Effects of habitat management on different feeding guilds of herbivorous insects in cacao agroforestry systems.

PubMed

Novais, Samuel M A; Macedo-Reis, Luiz E; DaRocha, Wesley D; Neves, Frederico S

2016-06-01

Human pressure on natural habitats increases the importance of agroforests for biodiversity conservation. The objective of this study was to evaluate the role of cacao traditional cultivation system (CTCS) on the conservation of the herbivorous insect community when compared with a monodominant rubber agroforest, a type of agricultural system for cacao cultivation. The insects were sampled in three habitats in Southeastern Bahia, Brazil: native forests, CTCS and rubber agroforests. In each habitat, 18 plots of 10 m2 were established, and the structural measures were collected and herbivorous insects were sampled with a Malaise/window trap. The diversity of folivorous decreased with the simplification of vegetation structure, but species composition was similar among habitats. In addition to a decrease in the availability of resources in monodominant rubber agroforests, the latex present in these systems have limited the occurrence of species that cannot circumvent latex toxicity. The diversity of sap-sucking insects was similar among habitats, but species composition was similar only in the CTCS and native forest, and it was different in the rubber agroforest. We observed turnover and a higher frequency of individuals of the family Psyllidae in the rubber agroforest. The biology and behavior of Psyllids and absence of natural enemies enable their diversity to increase when they are adapted to a new host. We observed a shift in the composition of xylophagous insects in the rubber agroforest compared to that in other habitats. Moreover, this agroforest has low species richness, but high individual abundance. Latex extraction is likely an important additional source of volatile compounds discharged into the environment, and it increases the attraction and recruitment of coleoborers to these sites. We concluded that CTCS has an herbivorous insect community with a structure similar to the community found in native forests of the region, and they present a more interesting conservation strategy when compared to rubber agroforests. We also emphasized the potential risk of local pest outbreaks in rubber agroforests for both the rubber and associated cacao trees.

Community shifts under climate change: mechanisms at multiple scales.

PubMed

Gornish, Elise S; Tylianakis, Jason M

2013-07-01

Processes that drive ecological dynamics differ across spatial scales. Therefore, the pathways through which plant communities and plant-insect relationships respond to changing environmental conditions are also expected to be scale-dependent. Furthermore, the processes that affect individual species or interactions at single sites may differ from those affecting communities across multiple sites. We reviewed and synthesized peer-reviewed literature to identify patterns in biotic or abiotic pathways underpinning changes in the composition and diversity of plant communities under three components of climate change (increasing temperature, CO2, and changes in precipitation) and how these differ across spatial scales. We also explored how these changes to plants affect plant-insect interactions. The relative frequency of biotic vs. abiotic pathways of climate effects at larger spatial scales often differ from those at smaller scales. Local-scale studies show variable responses to climate drivers, often driven by biotic factors. However, larger scale studies identify changes to species composition and/or reduced diversity as a result of abiotic factors. Differing pathways of climate effects can result from different responses of multiple species, habitat effects, and differing effects of invasions at local vs. regional to global scales. Plant community changes can affect higher trophic levels as a result of spatial or phenological mismatch, foliar quality changes, and plant abundance changes, though studies on plant-insect interactions at larger scales are rare. Climate-induced changes to plant communities will have considerable effects on community-scale trophic exchanges, which may differ from the responses of individual species or pairwise interactions.

Fragmentation and Management of Ethiopian Moist Evergreen Forest Drive Compositional Shifts of Insect Communities Visiting Wild Arabica Coffee Flowers

NASA Astrophysics Data System (ADS)

Berecha, Gezahegn; Aerts, Raf; Muys, Bart; Honnay, Olivier

2015-02-01

Coffea arabica is an indigenous understorey shrub of the moist evergreen Afromontane forest of SW Ethiopia. Coffee cultivation here occurs under different forest management intensities, ranging from almost no intervention in the `forest coffee' system to far-reaching interventions that include the removal of competing shrubs and selective thinning of the upper canopy in the `semi-forest coffee' system. We investigated whether increasing forest management intensity and fragmentation result in impacts upon potential coffee pollination services through examining shifts in insect communities that visit coffee flowers. Overall, we netted 2,976 insect individuals on C. arabica flowers, belonging to sixteen taxonomic groups, comprising 10 insect orders. Taxonomic richness of the flower-visiting insects significantly decreased and pollinator community changed with increasing forest management intensity and fragmentation. The relative abundance of honey bees significantly increased with increasing forest management intensity and fragmentation, likely resulting from the introduction of bee hives in the most intensively managed forests. The impoverishment of the insect communities through increased forest management intensity and fragmentation potentially decreases the resilience of the coffee production system as pollination increasingly relies on honey bees alone. This may negatively affect coffee productivity in the long term as global pollination services by managed honey bees are expected to decline under current climate change scenarios. Coffee agroforestry management practices should urgently integrate pollinator conservation measures.

Necrophilous Insect Dynamics at Small Vertebrate Carrion in a Temperate Eucalypt Woodland.

PubMed

Barton, Philip S; Evans, Maldwyn J; Pechal, Jennifer L; Benbow, M Eric

2017-07-01

Insects associated with carrion are critical to the decomposition process and nutrient cycling in ecosystems. Yet the communities of insects associated with carrion vary between locations, and detailed case studies are necessary for identifying differences and similarities among contrasting habitats. In this study, we examined temporal changes in the crawling insect community collected from rabbit carcasses placed in contrasting grassland and tree habitats in southeastern Australia. We collected 18,400 adult insects, including 22 species of fly, 57 species of beetle, and 37 species of ant. We found significant effects of habitat type and time, but not their interaction, on the composition of the entire insect community. Several ant species showed early and rapid colonization and highest abundances during early stages of decay, including Iridomyrmex purpureus (Smith, 1858) under trees, and Iridomyrmex rufoniger (Lowne, 1865) and Rhytidoponera metallica (Smith, 1858) in grassland. We found that most fly species showed highest abundance during active decay, but Chrysomya varipes (Macquart 1851) was more abundant under trees than in grassland during this time. Beetles peaked during active or advanced decay stages, with Saprinus and Omorgus the most abundant genera. Our study demonstrates that strong replication of contrasting environmental treatments can reveal new information on habitat preferences of important carrion insect species. The numerical dominance of ants early in decomposition has implications for insect community structure via potential competitive interactions with flies, and should be more rigorously examined in future carrion studies. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Sources of Variation in the Gut Microbial Community of Lycaeides melissa Caterpillars.

PubMed

Chaturvedi, Samridhi; Rego, Alexandre; Lucas, Lauren K; Gompert, Zachariah

2017-09-12

Microbes can mediate insect-plant interactions and have been implicated in major evolutionary transitions to herbivory. Whether microbes also play a role in more modest host shifts or expansions in herbivorous insects is less clear. Here we evaluate the potential for gut microbial communities to constrain or facilitate host plant use in the Melissa blue butterfly (Lycaeides melissa). We conducted a larval rearing experiment where caterpillars from two populations were fed plant tissue from two hosts. We used 16S rRNA sequencing to quantify the relative effects of sample type (frass versus whole caterpillar), diet (plant species), butterfly population and development (caterpillar age) on the composition and diversity of the caterpillar gut microbial communities, and secondly, to test for a relationship between microbial community and larval performance. Gut microbial communities varied over time (that is, with caterpillar age) and differed between frass and whole caterpillar samples. Diet (host plant) and butterfly population had much more limited effects on microbial communities. We found no evidence that gut microbe community composition was associated with caterpillar weight, and thus, our results provide no support for the hypothesis that variation in microbial community affects performance in L. melissa.

Effect of variable rates of daily sampling of fly larvae on decomposition and carrion insect community assembly: implications for forensic entomology field study protocols.

PubMed

Michaud, Jean-Philippe; Moreau, Gaétan

2013-07-01

Experimental protocols in forensic entomology successional field studies generally involve daily sampling of insects to document temporal changes in species composition on animal carcasses. One challenge with that method has been to adjust the sampling intensity to obtain the best representation of the community present without affecting the said community. To this date, little is known about how such investigator perturbations affect decomposition-related processes. Here, we investigated how different levels of daily sampling of fly eggs and fly larvae affected, over time, carcass decomposition rate and the carrion insect community. Results indicated that a daily sampling of <5% of the egg and larvae volumes present on a carcass, a sampling intensity believed to be consistent with current accepted practices in successional field studies, had little effect overall. Higher sampling intensities, however, slowed down carcass decomposition, affected the abundance of certain carrion insects, and caused an increase in the volume of eggs laid by dipterans. This study suggests that the carrion insect community not only has a limited resilience to recurrent perturbations but that a daily sampling intensity equal to or <5% of the egg and larvae volumes appears adequate to ensure that the system is representative of unsampled conditions. Hence we propose that this threshold be accepted as best practice in future forensic entomology successional field studies.

Seasonal Patterns of the Insect Community Structure in Urban Rain Pools of Temperate Argentina

PubMed Central

Fontanarrosa, M. Soledad; Collantes, Marta B.; Bachmann, Axel O.

2009-01-01

Temporary aquatic environments are widespread in the world, and although there are considerable regional differences in their type and method of formation they have many physical, chemical and biological properties in common. With the aim to increase knowledge of urban temporary pool fauna, the objectives of this work were to assess the seasonal patterns of species composition, richness, and diversity of the aquatic insect community inhabiting rain pools in urban temperate Argentina, and to identify the environmental variables associated to these patterns. Four temporary pools of an urban green space in Buenos Aires City were studied throughout a 1-year period. Eleven flood cycles with very varied hydroperiods and dry periods, mainly associated with rainfall, were identified. Insect species richness in these temporary urban pools, 86 taxa were documented, was found to be within the range reported for wild temporary water bodies of other regions of the world. The present results provide evidence for the existence of a clear link between habitat and community variability. Hydroperiod and seasonality were the main environmental factors involved in structuring the insect communities of the studied water bodies. Urban pools in green spaces have the potential to act to its dwellers like corridors through the urban matrix. Taking into account these characteristics and their accessibility, urban temporary pools can be considered as promising habitats for the study of ecological processes involving the insect community. PMID:19611261

Exotic weevil invasion increases floral herbivore community density, function, and impact on a native plant

USDA-ARS?s Scientific Manuscript database

Consumer communities are being re-arranged through unprecedented rates of human-mediated invasions and extinctions. Such changes in consumer composition and diversity potentially alter pressure and impact on resource populations. Although insect herbivore invasions are common, and exotic herbivores...

The Role of Small Woodland Remnants on Ground Dwelling Insect Conservation in Chaco Serrano, Central Argentina

PubMed Central

Moreno, María Laura; Fernández, María Guadalupe; Molina, Silvia Itati; Valladares, Graciela

2013-01-01

Many terrestrial ecosystems are changing due to extensive land use and habitat fragmentation, posing a major threat to biodiversity. In this study, the effects of patch size, isolation, and edge/interior localization on the ground dwelling insect communities in the Chaco Serrano woodland remnants in central Argentina were examined. Sampling was carried out in December 2003 and March 2004 in nine remnants (0.57 to 1000 hectares) using pitfall traps. In total, 7071 individuals representing 12 orders and 79 families were recorded. The taxonomic composition of these communities was linked to remnant size. Insect abundance increased (as did their richness, albeit marginally) as remnant area decreased, with no significant effects of isolation or edge/interior localization on abundance, richness, or diversity. No differential area effects were observed when abundance and richness of predators, scavengers, and herbivores were compared. Thus, ground insect communities in fragmented Chaco Serrano seem to respond mainly to patch level, rather than to within-patch (edge effects) or landscape (isolation) level variables. These results suggest that small Chaco Serrano remnants, by supporting larger ground-dwelling insect assemblages, may play an important role from a conservation viewpoint. PMID:23902409

The role of small woodland remnants on ground dwelling insect conservation in Chaco Serrano, Central Argentina.

PubMed

Moreno, María Laura; Fernández, María Guadalupe; Molina, Silvia Itati; Valladares, Graciela

2013-01-01

Many terrestrial ecosystems are changing due to extensive land use and habitat fragmentation, posing a major threat to biodiversity. In this study, the effects of patch size, isolation, and edge/interior localization on the ground dwelling insect communities in the Chaco Serrano woodland remnants in central Argentina were examined. Sampling was carried out in December 2003 and March 2004 in nine remnants (0.57 to 1000 hectares) using pitfall traps. In total, 7071 individuals representing 12 orders and 79 families were recorded. The taxonomic composition of these communities was linked to remnant size. Insect abundance increased (as did their richness, albeit marginally) as remnant area decreased, with no significant effects of isolation or edge/interior localization on abundance, richness, or diversity. No differential area effects were observed when abundance and richness of predators, scavengers, and herbivores were compared. Thus, ground insect communities in fragmented Chaco Serrano seem to respond mainly to patch level, rather than to within-patch (edge effects) or landscape (isolation) level variables. These results suggest that small Chaco Serrano remnants, by supporting larger ground-dwelling insect assemblages, may play an important role from a conservation viewpoint.

Seasonal necrophagous insect community assembly during vertebrate carrion decomposition.

PubMed

Benbow, M E; Lewis, A J; Tomberlin, J K; Pechal, J L

2013-03-01

Necrophagous invertebrates have been documented to be a predominant driver of vertebrate carrion decomposition; however, very little is understood about the assembly of these communities both within and among seasons. The objective of this study was to evaluate the seasonal differences in insect taxa composition, richness, and diversity on carrion over decomposition with the intention that such data will be useful for refining error estimates in forensic entomology. Sus scrofa (L.) carcasses (n = 3-6, depending on season) were placed in a forested habitat near Xenia, OH, during spring, summer, autumn, and winter. Taxon richness varied substantially among seasons but was generally lower (1-2 taxa) during early decomposition and increased (3-8 taxa) through intermediate stages of decomposition. Autumn and winter showed the highest richness during late decomposition. Overall, taxon richness was higher during active decay for all seasons. While invertebrate community composition was generally consistent among seasons, the relative abundance of five taxa significantly differed across seasons, demonstrating different source communities for colonization depending on the time of year. There were significantly distinct necrophagous insect communities for each stage of decomposition, and between summer and autumn and summer and winter, but the communities were similar between autumn and winter. Calliphoridae represented significant indicator taxa for summer and autumn but replaced by Coleoptera during winter. Here we demonstrated substantial variability in necrophagous communities and assembly on carrion over decomposition and among seasons. Recognizing this variation has important consequences for forensic entomology and future efforts to provide error rates for estimates of the postmortem interval using arthropod succession data as evidence during criminal investigations.

Species turnover drives β-diversity patterns across multiple spatial scales of plant-galling interactions in mountaintop grasslands.

PubMed

Coelho, Marcel Serra; Carneiro, Marco Antônio Alves; Branco, Cristina Alves; Borges, Rafael Augusto Xavier; Fernandes, Geraldo Wilson

2018-01-01

This study describes differences in species richness and composition of the assemblages of galling insects and their host plants at different spatial scales. Sampling was conducted along altitudinal gradients composed of campos rupestres and campos de altitude of two mountain complexes in southeastern Brazil: Espinhaço Range and Mantiqueira Range. The following hypotheses were tested: i) local and regional richness of host plants and galling insects are positively correlated; ii) beta diversity is the most important component of regional diversity of host plants and galling insects; and iii) Turnover is the main mechanism driving beta diversity of both host plants and galling insects. Local richness of galling insects and host plants increased with increasing regional richness of species, suggesting a pattern of unsaturated communities. The additive partition of regional richness (γ) into local and beta components shows that local richnesses (α) of species of galling insects and host plants are low relative to regional richness; the beta (β) component incorporates most of the regional richness. The multi-scale analysis of additive partitioning showed similar patterns for galling insects and host plants with the local component (α) incorporated a small part of regional richness. Beta diversity of galling insects and host plants were mainly the result of turnover, with little contribution from nesting. Although the species composition of galling insects and host plant species varied among sample sites, mountains and even mountain ranges, local richness remained relatively low. In this way, the addition of local habitats with different landscapes substantially affects regional richness. Each mountain contributes fundamentally to the composition of regional diversity of galling insects and host plants, and so the design of future conservation strategies should incorporate multiple scales.

Insect herbivory and plant adaptation in an early successional community.

PubMed

Agrawal, Anurag A; Hastings, Amy P; Fines, Daniel M; Bogdanowicz, Steve; Huber, Meret

2018-05-01

To address the role of insect herbivores in adaptation of plant populations and the persistence of selection through succession, we manipulated herbivory in a long-term field experiment. We suppressed insects in half of 16 plots over nine years and examined the genotypic structure and chemical defense of common dandelion (Taraxacum officinale), a naturally colonizing perennial apomictic plant. Insect suppression doubled dandelion abundance in the first few years, but had negligible effects thereafter. Using microsatellite DNA markers, we genotyped >2500 plants and demonstrate that insect suppression altered the genotypic composition of plots in both sampling years. Phenotypic and genotypic estimates of defensive terpenes and phenolics from the field plots allowed us to infer phenotypic plasticity and the response of dandelion populations to insect-mediated natural selection. The effects of insect suppression on plant chemistry were, indeed, driven both by plasticity and plant genotypic identity. In particular, di-phenolic inositol esters were more abundant in plots exposed to herbivory (due to the genotypic composition of the plots) and were also induced in response to herbivory. This field experiment thus demonstrates evolutionary sorting of plant genotypes in response to insect herbivores that was in same direction as the plastic defensive response within genotypes. © 2018 The Author(s). Evolution © 2018 The Society for the Study of Evolution.

The role of dead wood in maintaining arthropod diversity on the forest floor

Treesearch

James L. Hanula; Scott Horn; Dale D. Wade

2006-01-01

Dead wood is a major component of forests and contributes to overall diversity, primarily by supporting insects that feed directly on or in it. Further, a variety of organisms benefit by feeding on those insects. What is not well known is how or whether dead wood influences the composition of the arthropod community that is not solely dependent on it as a food...

Community analysis of microbial sharing and specialization in a Costa Rican ant-plant-hemipteran symbiosis.

PubMed

Pringle, Elizabeth G; Moreau, Corrie S

2017-03-15

Ants have long been renowned for their intimate mutualisms with trophobionts and plants and more recently appreciated for their widespread and diverse interactions with microbes. An open question in symbiosis research is the extent to which environmental influence, including the exchange of microbes between interacting macroorganisms, affects the composition and function of symbiotic microbial communities. Here we approached this question by investigating symbiosis within symbiosis. Ant-plant-hemipteran symbioses are hallmarks of tropical ecosystems that produce persistent close contact among the macroorganism partners, which then have substantial opportunity to exchange symbiotic microbes. We used metabarcoding and quantitative PCR to examine community structure of both bacteria and fungi in a Neotropical ant-plant-scale-insect symbiosis. Both phloem-feeding scale insects and honeydew-feeding ants make use of microbial symbionts to subsist on phloem-derived diets of suboptimal nutritional quality. Among the insects examined here, Cephalotes ants and pseudococcid scale insects had the most specialized bacterial symbionts, whereas Azteca ants appeared to consume or associate with more fungi than bacteria, and coccid scale insects were associated with unusually diverse bacterial communities. Despite these differences, we also identified apparent sharing of microbes among the macro-partners. How microbial exchanges affect the consumer-resource interactions that shape the evolution of ant-plant-hemipteran symbioses is an exciting question that awaits further research. © 2017 The Author(s).

Using dung beetles to evaluate the effects of urbanization on Atlantic Forest biodiversity.

PubMed

Korasaki, Vanesca; Lopes, José; Gardner Brown, George; Louzada, Julio

2013-06-01

We used dung beetles to evaluate the impact of urbanization on insect biodiversity in three Atlantic Forest fragments in Londrina, Paraná, Brazil. This study provides the first empirical evidence of the impact of urbanization on richness, abundance, composition and guild structure of dung beetle communities from the Brazilian Atlantic Forest. We evaluated the community aspects (abundance, richness, composition and food guilds) of dung beetles in fragments with different degrees of immersion in the urban matrix using pitfall traps with four alternative baits (rotten meat, rotten fish, pig dung and decaying banana). A total of 1 719 individuals were collected, belonging to 29 species from 11 genera and six Scarabaeinae tribes. The most urban-immersed fragment showed a higher species dominance and the beetle community captured on dung presented the greatest evenness. The beetle communities were distinct with respect to the fragments and feeding habits. Except for the dung beetle assemblage in the most urbanized forest fragment, all others exhibited contrasting differences in species composition attracted to each bait type. Our results clearly show that the degree of urbanization affects Atlantic Forest dung beetle communities and that the preservation of forest fragments inside the cities, even small ones, can provide refuges for Scarabaeinae. © 2012 The Authors Insect Science © 2012 Institute of Zoology, Chinese Academy of Sciences.

Land-use history alters contemporary insect herbivore community composition and decouples plant-herbivore relationships

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, Philip G.; Orrock, John L.

1. Past land use can create altered soil conditions and plant communities that persist for decades, although the effects of these altered conditions on consumers are rarely investigated. 2. Using a large-scale field study at 36 sites in longleaf pine (Pinus palustris) woodlands, we examined whether historic agricultural land use leads to differences in the abundance and community composition of insect herbivores (grasshoppers, families Acrididae and Tettigoniidae). 3. We measured the cover of six plant functional groups and several environmental variables to determine whether historic agricultural land use affects the relationships between plant cover or environmental conditions and grasshopper assemblages.more » 4. Land-use history had taxa-specific effects and interacted with herbaceous plant cover to alter grasshopper abundances, leading to significant changes in community composition. Abundance of most grasshopper taxa increased with herbaceous cover in woodlands with no history of agriculture, but there was no relationship in post-agricultural woodlands. We also found that grasshopper abundance was negatively correlated with leaf litter cover. Soil hardness was greater in post-agricultural sites (i.e. more compacted) and was associated with grasshopper community composition. Both herbaceous cover and leaf litter cover are influenced by fire frequency, suggesting a potential indirect role of fire on grasshopper assemblages. 5. Our results demonstrate that historic land use may create persistent differences in the composition of grasshopper assemblages, while contemporary disturbances (e.g. prescribed fire) may be important for determining the abundance of grasshoppers, largely through the effect of fire on plants and leaf litter. Therefore, our results suggest that changes in the contemporary management regimes (e.g. increasing prescribed fire) may not be sufficient to shift the structure of grasshopper communities in post-agricultural sites towards communities in nonagricultural habitats. Rather, repairing degraded soil conditions and restoring plant communities are likely necessary for restoring grasshopper assemblages in post-agricultural woodlands.« less

Land-use history alters contemporary insect herbivore community composition and decouples plant-herbivore relationships

DOE PAGES

Hahn, Philip G.; Orrock, John L.

2014-11-23

1. Past land use can create altered soil conditions and plant communities that persist for decades, although the effects of these altered conditions on consumers are rarely investigated. 2. Using a large-scale field study at 36 sites in longleaf pine (Pinus palustris) woodlands, we examined whether historic agricultural land use leads to differences in the abundance and community composition of insect herbivores (grasshoppers, families Acrididae and Tettigoniidae). 3. We measured the cover of six plant functional groups and several environmental variables to determine whether historic agricultural land use affects the relationships between plant cover or environmental conditions and grasshopper assemblages.more » 4. Land-use history had taxa-specific effects and interacted with herbaceous plant cover to alter grasshopper abundances, leading to significant changes in community composition. Abundance of most grasshopper taxa increased with herbaceous cover in woodlands with no history of agriculture, but there was no relationship in post-agricultural woodlands. We also found that grasshopper abundance was negatively correlated with leaf litter cover. Soil hardness was greater in post-agricultural sites (i.e. more compacted) and was associated with grasshopper community composition. Both herbaceous cover and leaf litter cover are influenced by fire frequency, suggesting a potential indirect role of fire on grasshopper assemblages. 5. Our results demonstrate that historic land use may create persistent differences in the composition of grasshopper assemblages, while contemporary disturbances (e.g. prescribed fire) may be important for determining the abundance of grasshoppers, largely through the effect of fire on plants and leaf litter. Therefore, our results suggest that changes in the contemporary management regimes (e.g. increasing prescribed fire) may not be sufficient to shift the structure of grasshopper communities in post-agricultural sites towards communities in nonagricultural habitats. Rather, repairing degraded soil conditions and restoring plant communities are likely necessary for restoring grasshopper assemblages in post-agricultural woodlands.« less

Resource specialists lead local insect community turnover associated with temperature - analysis of an 18-year full-seasonal record of moths and beetles.

PubMed

Thomsen, Philip Francis; Jørgensen, Peter Søgaard; Bruun, Hans Henrik; Pedersen, Jan; Riis-Nielsen, Torben; Jonko, Krzysztof; Słowińska, Iwona; Rahbek, Carsten; Karsholt, Ole

2016-01-01

Insect responses to recent climate change are well documented, but the role of resource specialization in determining species vulnerability remains poorly understood. Uncovering local ecological effects of temperature change with high-quality, standardized data provides an important first opportunity for predictions about responses of resource specialists, and long-term time series are essential in revealing these responses. Here, we investigate temperature-related changes in local insect communities, using a sampling site with more than a quarter-million records from two decades (1992-2009) of full-season, quantitative light trapping of 1543 species of moths and beetles. We investigated annual as well as long-term changes in fauna composition, abundance and phenology in a climate-related context using species temperature affinities and local temperature data. Finally, we explored these local changes in the context of dietary specialization. Across both moths and beetles, temperature affinity of specialists increased through net gain of hot-dwelling species and net loss of cold-dwelling species. The climate-related composition of generalists remained constant over time. We observed an increase in species richness of both groups. Furthermore, we observed divergent phenological responses between cold- and hot-dwelling species, advancing and delaying their relative abundance, respectively. Phenological advances were particularly pronounced in cold-adapted specialists. Our results suggest an important role of resource specialization in explaining the compositional and phenological responses of insect communities to local temperature increases. We propose that resource specialists in particular are affected by local temperature increase, leading to the distinct temperature-mediated turnover seen for this group. We suggest that the observed increase in species number could have been facilitated by dissimilar utilization of an expanded growing season by cold- and hot-adapted species, as indicated by their oppositely directed phenological responses. An especially pronounced advancement of cold-adapted specialists suggests that such phenological advances might help minimize further temperature-induced loss of resource specialists. Although limited to a single study site, our results suggest several local changes in the insect fauna in concordance with expected change of larger-scale temperature increases. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

Assessment of beetle diversity, community composition and potential threats to forestry using kairomone-baited traps.

PubMed

Olivier-Espejel, S; Hurley, B P; Garnas, J

2017-02-01

Traps designed to capture insects during normal movement/dispersal, or via attraction to non-specific (plant) volatile lures, yield by-catch that carries valuable information about patterns of community diversity and composition. In order to identify potential native/introduced pests and detect predictors of colonization of non-native pines, we examined beetle assemblages captured in intercept panel traps baited with kairomone lures used during a national monitoring of the woodwasp, Sirex noctilio, in Southern Africa. We identified 50 families and 436 morphospecies of beetles from nine sites sampled in both 2008 and 2009 and six areas in 2007 (trap catch pooled by region) across a latitudinal and elevational gradient. The most diverse groups were mainly those strongly associated with trees, known to include damaging pests. While native species dominated the samples in terms of richness, the dominant species was the introduced bark beetle Orthotomicus erosus (Curculionidae: Scolytinae) (22 ± 34 individuals/site). Four Scolytinae species without previous records in South Africa, namely Coccotrypes niger, Hypocryphalus robustus (formerly Hypocryphalus mangiferae), Hypothenemus birmanus and Xyleborus perforans, were captured in low abundances. Communities showed temporal stability within sites and strong biogeographic patterns across the landscape. The strongest single predictors of community composition were potential evaporation, latitude and maximum relative humidity, while the strongest multifactor model contained elevation, potential evaporation and maximum relative humidity. Temperature, land use variables and distance to natural areas did not significantly correlate with community composition. Non-phytophagous beetles were also captured and were highly diverse (32 families) perhaps representing important beneficial insects.

Metagenomic analysis of fungal diversity on strawberry plants and the effect of management practices on the fungal community structure of aerial organs

USDA-ARS?s Scientific Manuscript database

Metabarcoding, defined as Next Generation Sequencing (NGS) of amplicons of the ITS2 region (DNA barcode), was used to identify the composition of the fungal community on different strawberry organs i.e. leaves, flowers, and immature and mature fruits grown on a farm using disease and insect control ...

Microbial community assessment of mealworm larvae (Tenebrio molitor) and grasshoppers (Locusta migratoria migratorioides) sold for human consumption.

PubMed

Stoops, J; Crauwels, S; Waud, M; Claes, J; Lievens, B; Van Campenhout, L

2016-02-01

In Western countries, the popularity of edible insects as an alternative animal protein source is increasing. Nevertheless, there is a lack of profound insight into the microbial safety and shelf life of living insects sold for human consumption. The purpose of this study was to characterise the microflora of fresh edible mealworm larvae and grasshoppers in a quantitative and qualitative way. Therefore, culture-dependent analyses (the total viable aerobic count, Enterobacteriaceae, lactic acid bacteria, yeasts and moulds, and bacterial endospores) and next-generation sequencing (454amplicon pyrosequencing) were performed. High microbial counts were obtained for both insect species. Different insect batches resulted in quite similar microbial numbers, except for bacterial endospores. However, the bacterial community composition differed between both insect species. The most abundant operational taxonomic unit in mealworm larvae was Propionibacterium. Also members of the genera Haemophilus, Staphylococcus and Clostridium were found. Grasshoppers were mainly dominated by Weissella, Lactococcus and Yersinia/Rahnella. Overall, a variety of potential spoilage bacteria and food pathogens were characterised. The results of this study suggest that a processing step with a microbiocidal effect is required to avoid or minimize risks involved with the consumption of edible insects. Copyright © 2015 Elsevier Ltd. All rights reserved.

The bacterial community of entomophilic nematodes and host beetles.

PubMed

Koneru, Sneha L; Salinas, Heilly; Flores, Gilberto E; Hong, Ray L

2016-05-01

Insects form the most species-rich lineage of Eukaryotes and each is a potential host for organisms from multiple phyla, including fungi, protozoa, mites, bacteria and nematodes. In particular, beetles are known to be associated with distinct bacterial communities and entomophilic nematodes. While entomopathogenic nematodes require symbiotic bacteria to kill and reproduce inside their insect hosts, the microbial ecology that facilitates other types of nematode-insect associations is largely unknown. To illuminate detailed patterns of the tritrophic beetle-nematode-bacteria relationship, we surveyed the nematode infestation profiles of scarab beetles in the greater Los Angeles area over a five-year period and found distinct nematode infestation patterns for certain beetle hosts. Over a single season, we characterized the bacterial communities of beetles and their associated nematodes using high-throughput sequencing of the 16S rRNA gene. We found significant differences in bacterial community composition among the five prevalent beetle host species, independent of geographical origin. Anaerobes Synergistaceae and sulphate-reducing Desulfovibrionaceae were most abundant in Amblonoxia beetles, while Enterobacteriaceae and Lachnospiraceae were common in Cyclocephala beetles. Unlike entomopathogenic nematodes that carry bacterial symbionts, insect-associated nematodes do not alter the beetles' native bacterial communities, nor do their microbiomes differ according to nematode or beetle host species. The conservation of Diplogastrid nematodes associations with Melolonthinae beetles and sulphate-reducing bacteria suggests a possible link between beetle-bacterial communities and their associated nematodes. Our results establish a starting point towards understanding the dynamic interactions between soil macroinvertebrates and their microbiota in a highly accessible urban environment. © 2016 John Wiley & Sons Ltd.

Genetic variation in foundation species governs the dynamics of trophic interactions

PubMed Central

Valencia-Cuevas, Leticia; Mussali-Galante, Patricia; Cano-Santana, Zenón; Pujade-Villar, Juli; Equihua-Martínez, Armando

2018-01-01

Abstract Various studies have demonstrated that the foundation species genetic diversity can have direct effects that extend beyond the individual or population level, affecting the dependent communities. Additionally, these effects may be indirectly extended to higher trophic levels throughout the entire community. Quercus castanea is an oak species with characteristics of foundation species beyond presenting a wide geographical distribution and being a dominant element of Mexican temperate forests. In this study, we analyzed the influence of population (He) and individual (HL) genetic diversity of Q. castanea on its canopy endophagous insect community and associated parasitoids. Specifically, we studied the composition, richness (S) and density of leaf-mining moths (Lepidoptera: Tischeridae, Citheraniidae), gall-forming wasps (Hymenoptera: Cynipidae), and canopy parasitoids of Q. castanea. We sampled 120 trees belonging to six populations (20/site) through the previously recognized gradient of genetic diversity. In total, 22 endophagous insect species belonging to three orders (Hymenoptera, Lepidoptera, and Diptera) and 20 parasitoid species belonging to 13 families were identified. In general, we observed that the individual genetic diversity of the host plant (HL) has a significant positive effect on the S and density of the canopy endophagous insect communities. In contrast, He has a significant negative effect on the S of endophagous insects. Additionally, indirect effects of HL were observed, affecting the S and density of parasitoid insects. Our results suggest that genetic variation in foundation species can be one of the most important factors governing the dynamics of tritrophic interactions that involve oaks, herbivores, and parasitoids. PMID:29492034

Nutritional ecology of entomophagy in humans and other primates.

PubMed

Raubenheimer, David; Rothman, Jessica M

2013-01-01

Entomophagy is widespread among nonhuman primates and is common among many human communities. However, the extent and patterns of entomophagy vary substantially both in humans and nonhuman primates. Here we synthesize the literature to examine why humans and other primates eat insects and what accounts for the variation in the extent to which they do so. Variation in the availability of insects is clearly important, but less understood is the role of nutrients in entomophagy. We apply a multidimensional analytical approach, the right-angled mixture triangle, to published data on the macronutrient compositions of insects to address this. Results showed that insects eaten by humans spanned a wide range of protein-to-fat ratios but were generally nutrient dense, whereas insects with high protein-to-fat ratios were eaten by nonhuman primates. Although suggestive, our survey exposes a need for additional, standardized, data.

Gut microbiomes of mobile predators vary with landscape context and species identity.

PubMed

Tiede, Julia; Scherber, Christoph; Mutschler, James; McMahon, Katherine D; Gratton, Claudio

2017-10-01

Landscape context affects predator-prey interactions and predator diet composition, yet little is known about landscape effects on insect gut microbiomes, a determinant of physiology and condition. Here, we combine laboratory and field experiments to examine the effects of landscape context on the gut bacterial community and body condition of predatory insects. Under laboratory conditions, we found that prey diversity increased bacterial richness in insect guts. In the field, we studied the performance and gut microbiota of six predatory insect species along a landscape complexity gradient in two local habitat types (soybean fields vs. prairie). Insects from soy fields had richer gut bacteria and lower fat content than those from prairies, suggesting better feeding conditions in prairies. Species origin mediated landscape context effects, suggesting differences in foraging of exotic and native predators on a landscape scale. Overall, our study highlights complex interactions among gut microbiota, predator identity, and landscape context.

Variability of Bacterial Communities in the Moth Heliothis virescens Indicates Transient Association with the Host

PubMed Central

Staudacher, Heike; Kaltenpoth, Martin; Breeuwer, Johannes A. J.; Menken, Steph B. J.; Heckel, David G.; Groot, Astrid T.

2016-01-01

Microbes associated with insects can confer a wide range of ecologically relevant benefits to their hosts. Since insect-associated bacteria often increase the nutritive value of their hosts' diets, the study of bacterial communities is especially interesting in species that are important agricultural pests. We investigated the composition of bacterial communities in the noctuid moth Heliothis virescens and its variability in relation to developmental stage, diet and population (field and laboratory), using bacterial tag-encoded FLX pyrosequencing of 16S rRNA amplicons. In larvae, bacterial communities differed depending on the food plant on which they had been reared, although the within-group variation between biological replicates was high as well. Moreover, larvae originating from a field or laboratory population did not share any OTUs. Interestingly, Enterococcus sp. was found to be the dominant taxon in laboratory-reared larvae, but was completely absent from field larvae, indicating dramatic shifts in microbial community profiles upon cultivation of the moths in the laboratory. Furthermore, microbiota composition varied strongly across developmental stages in individuals of the field population, and we found no evidence for vertical transmission of bacteria from mothers to offspring. Since sample sizes in our study were small due to pooling of samples for sequencing, we cautiously conclude that the high variability in bacterial communities suggests a loose and temporary association of the identified bacteria with H. virescens. PMID:27139886

Microbial Community Functional Change during Vertebrate Carrion Decomposition

PubMed Central

Pechal, Jennifer L.; Crippen, Tawni L.; Tarone, Aaron M.; Lewis, Andrew J.; Tomberlin, Jeffery K.; Benbow, M. Eric

2013-01-01

Microorganisms play a critical role in the decomposition of organic matter, which contributes to energy and nutrient transformation in every ecosystem. Yet, little is known about the functional activity of epinecrotic microbial communities associated with carrion. The objective of this study was to provide a description of the carrion associated microbial community functional activity using differential carbon source use throughout decomposition over seasons, between years and when microbial communities were isolated from eukaryotic colonizers (e.g., necrophagous insects). Additionally, microbial communities were identified at the phyletic level using high throughput sequencing during a single study. We hypothesized that carrion microbial community functional profiles would change over the duration of decomposition, and that this change would depend on season, year and presence of necrophagous insect colonization. Biolog EcoPlates™ were used to measure the variation in epinecrotic microbial community function by the differential use of 29 carbon sources throughout vertebrate carrion decomposition. Pyrosequencing was used to describe the bacterial community composition in one experiment to identify key phyla associated with community functional changes. Overall, microbial functional activity increased throughout decomposition in spring, summer and winter while it decreased in autumn. Additionally, microbial functional activity was higher in 2011 when necrophagous arthropod colonizer effects were tested. There were inconsistent trends in the microbial function of communities isolated from remains colonized by necrophagous insects between 2010 and 2011, suggesting a greater need for a mechanistic understanding of the process. These data indicate that functional analyses can be implemented in carrion studies and will be important in understanding the influence of microbial communities on an essential ecosystem process, carrion decomposition. PMID:24265741

Habitat Re-Creation (Ecological Restoration) as a Strategy for Conserving Insect Communities in Highly Fragmented Landscapes

PubMed Central

Shuey, John A.

2013-01-01

Because of their vast diversity, measured by both numbers of species as well as life history traits, insects defy comprehensive conservation planning. Thus, almost all insect conservation efforts target individual species. However, serious insect conservation requires goals that are set at the faunal level and conservation success requires strategies that conserve intact communities. This task is complicated in agricultural landscapes by high levels of habitat fragmentation and isolation. In many regions, once widespread insect communities are now functionally trapped on islands of ecosystem remnants and subject to a variety of stressors associated with isolation, small population sizes and artificial population fragmentation. In fragmented landscapes ecological restoration can be an effective strategy for reducing localized insect extinction rates, but insects are seldom included in restoration design criteria. It is possible to incorporate a few simple conservation criteria into restoration designs that enhance impacts to entire insect communities. Restoration can be used as a strategy to address fragmentation threats to isolated insect communities if insect communities are incorporated at the onset of restoration planning. Fully incorporating insect communities into restoration designs may increase the cost of restoration two- to three-fold, but the benefits to biodiversity conservation and the ecological services provided by intact insect communities justify the cost. PMID:26462535

Habitat Re-Creation (Ecological Restoration) as a Strategy for Conserving Insect Communities in Highly Fragmented Landscapes.

PubMed

Shuey, John A

2013-12-05

Because of their vast diversity, measured by both numbers of species as well as life history traits, insects defy comprehensive conservation planning. Thus, almost all insect conservation efforts target individual species. However, serious insect conservation requires goals that are set at the faunal level and conservation success requires strategies that conserve intact communities. This task is complicated in agricultural landscapes by high levels of habitat fragmentation and isolation. In many regions, once widespread insect communities are now functionally trapped on islands of ecosystem remnants and subject to a variety of stressors associated with isolation, small population sizes and artificial population fragmentation. In fragmented landscapes ecological restoration can be an effective strategy for reducing localized insect extinction rates, but insects are seldom included in restoration design criteria. It is possible to incorporate a few simple conservation criteria into restoration designs that enhance impacts to entire insect communities. Restoration can be used as a strategy to address fragmentation threats to isolated insect communities if insect communities are incorporated at the onset of restoration planning. Fully incorporating insect communities into restoration designs may increase the cost of restoration two- to three-fold, but the benefits to biodiversity conservation and the ecological services provided by intact insect communities justify the cost.

Census of the bacterial community of the gypsy moth larval midgut by using culturing and culture-independent methods.

PubMed

Broderick, Nichole A; Raffa, Kenneth F; Goodman, Robert M; Handelsman, Jo

2004-01-01

Little is known about bacteria associated with Lepidoptera, the large group of mostly phytophagous insects comprising the moths and butterflies. We inventoried the larval midgut bacteria of a polyphagous foliivore, the gypsy moth (Lymantria dispar L.), whose gut is highly alkaline, by using traditional culturing and culture-independent methods. We also examined the effects of diet on microbial composition. Analysis of individual third-instar larvae revealed a high degree of similarity of microbial composition among insects fed on the same diet. DNA sequence analysis indicated that most of the PCR-amplified 16S rRNA genes belong to the gamma-Proteobacteria and low G+C gram-positive divisions and that the cultured members represented more than half of the phylotypes identified. Less frequently detected taxa included members of the alpha-Proteobacterium, Actinobacterium, and Cytophaga/Flexibacter/Bacteroides divisions. The 16S rRNA gene sequences from 7 of the 15 cultured organisms and 8 of the 9 sequences identified by PCR amplification diverged from previously reported bacterial sequences. The microbial composition of midguts differed substantially among larvae feeding on a sterilized artificial diet, aspen, larch, white oak, or willow. 16S rRNA analysis of cultured isolates indicated that an Enterococcus species and culture-independent analysis indicated that an Entbacter sp. were both present in all larvae, regardless of the feeding substrate; the sequences of these two phylotypes varied less than 1% among individual insects. These results provide the first comprehensive description of the microbial diversity of a lepidopteran midgut and demonstrate that the plant species in the diet influences the composition of the gut bacterial community.

Dietary and developmental shifts in butterfly-associated bacterial communities

PubMed Central

2018-01-01

Bacterial communities associated with insects can substantially influence host ecology, evolution and behaviour. Host diet is a key factor that shapes bacterial communities, but the impact of dietary transitions across insect development is poorly understood. We analysed bacterial communities of 12 butterfly species across different developmental stages, using amplicon sequencing of the 16S rRNA gene. Butterfly larvae typically consume leaves of a single host plant, whereas adults are more generalist nectar feeders. Thus, we expected bacterial communities to vary substantially across butterfly development. Surprisingly, only few species showed significant dietary and developmental transitions in bacterial communities, suggesting weak impacts of dietary transitions across butterfly development. On the other hand, bacterial communities were strongly influenced by butterfly species and family identity, potentially due to dietary and physiological variation across the host phylogeny. Larvae of most butterfly species largely mirrored bacterial community composition of their diets, suggesting passive acquisition rather than active selection. Overall, our results suggest that although butterflies harbour distinct microbiomes across taxonomic groups and dietary guilds, the dramatic dietary shifts that occur during development do not impose strong selection to maintain distinct bacterial communities across all butterfly hosts. PMID:29892359

Laboratory colonization stabilizes the naturally dynamic microbiome composition of field collected dermacentor andersoni ticks

USDA-ARS?s Scientific Manuscript database

Nearly a quarter of emerging infectious diseases in the last century were transmitted by arthropods. Although ticks and insects can carry pathogenic microorganisms, non-pathogenic microbes make up the majority of the microbial community. Currently, the majority of tick microbiome research has had a ...

Functional homogenization of flower visitor communities with urbanization.

PubMed

Deguines, Nicolas; Julliard, Romain; de Flores, Mathieu; Fontaine, Colin

2016-04-01

Land-use intensification and resulting habitat loss are put forward as the main causes of flower visitor decline. However, the impact of urbanization, the prime driver of land-use intensification in Europe, is poorly studied. In particular, our understanding of whether and how it affects the composition and functioning of flower visitor assemblages is scant, yet required to cope with increasing urbanization worldwide. Here, we use a nation-wide dataset of plant-flower visitor (Coleoptera, Diptera, Hymenoptera, Lepidoptera) interactions sampled by citizen scientists following a standardized protocol to assess macroecological changes in richness and composition of flower visitor communities with urbanization. We measured the community composition by quantifying the relative occurrence of generalist and specialist flower visitors based on their specialisation on flowering plant families. We show that urbanization is associated with reduced flower visitor richness and a shift in community composition toward generalist insects, indicating a modification of the functional composition of communities. These results suggest that urbanization affects not only the richness of flower visitor assemblages but may also cause their large-scale functional homogenization. Future research should focus on designing measures to reconcile urban development with flower visitor conservation.

Effect of rice husk biochar application to soil insect diversity on potato cultivation

NASA Astrophysics Data System (ADS)

Meilin, A.; Rubiana, R.

2018-02-01

High intensity of disease infection and the intensive use of fertilizers and pesticidescause saturated fertilizer and pesticide to the land. Remediation using biochar rice husk is one of the technology to decrease fertilizer and pesticide residue. The diversity of soil insects can be used as bioindicators because of their existence dependsg on soil structure and condition. This study was aimed to study the diversity and structure communities of soil insect in potatoes on difference husk rice biochar application. The sampling of soil insects was done on potato farmer’s land with four treatments i.e control (farmers’ technique), trichokompos without biochar, trichokompos + biochar with dose 1 ton/ha, and trichokompos + biochar with dose 2 ton / ha. At each point a single pitfall trap was installed for two nights and then it was taken for identification. The results showed that biochar application had significant effect on the number of soil insect species (P = 0.037). The soil insect species composition pattern also showed significant differences between the four treatments (R: 0.2306, Pvalue = 0.001). This mean that the application of biochar affects the number of insects species and plays a role in the formation of soil insect diversity beta patterns.

The bacterial composition within the Sarracenia purpurea model system: local scale differences and the relationship with the other members of the food web.

PubMed

Gray, Sarah M; Akob, Denise M; Green, Stefan J; Kostka, Joel E

2012-01-01

The leaves of the carnivorous pitcher plant, Sarracenia purpurea, contain a microscopic aquatic food web that is considered a model system in ecological research. The species identity of the intermediate and top trophic level of this food web, as well the detritivore midge, are highly similar across the native geographic range of S. purpurea and, in some cases, appear to have co-evolved with the plant. However, until recently, the identity, geographic variation, and diversity of the bacteria in the bottom trophic level of this food web have remained largely unknown. This study investigated bacterial community composition inside the leaves of S. purpurea to address: 1) variation in bacterial communities at the beginning of succession at the local scale in different areas of the plant's native geographic range (southern and mid-regional sites) and 2) the impacts of bacterial consumers and other members of the aquatic food web (i.e., insects) on bacterial community structure. Communities from six leaves (one leaf per plant) from New York and Florida study sites were analyzed using 16S ribosomal RNA gene cloning. Each pitcher within each site had a distinct community; however, there was more overlap in bacterial composition within each site than when communities were compared across sites. In contrast, the identity of protozoans and metazoans in this community were similar in species identity both within a site and between the two sites, but abundances differed. Our results indicate that, at least during the beginning of succession, there is no strong selection for bacterial taxa and that there is no core group of bacteria required by the plant to start the decomposition of trapped insects. Co-evolution between the plant and bacteria appears to not have occurred as it has for other members of this community.

The Bacterial Composition within the Sarracenia purpurea Model System: Local Scale Differences and the Relationship with the Other Members of the Food Web

PubMed Central

Gray, Sarah M.; Akob, Denise M.; Green, Stefan J.; Kostka, Joel E.

2012-01-01

The leaves of the carnivorous pitcher plant, Sarracenia purpurea, contain a microscopic aquatic food web that is considered a model system in ecological research. The species identity of the intermediate and top trophic level of this food web, as well the detritivore midge, are highly similar across the native geographic range of S. purpurea and, in some cases, appear to have co-evolved with the plant. However, until recently, the identity, geographic variation, and diversity of the bacteria in the bottom trophic level of this food web have remained largely unknown. This study investigated bacterial community composition inside the leaves of S. purpurea to address: 1) variation in bacterial communities at the beginning of succession at the local scale in different areas of the plant’s native geographic range (southern and mid-regional sites) and 2) the impacts of bacterial consumers and other members of the aquatic food web (i.e., insects) on bacterial community structure. Communities from six leaves (one leaf per plant) from New York and Florida study sites were analyzed using 16S ribosomal RNA gene cloning. Each pitcher within each site had a distinct community; however, there was more overlap in bacterial composition within each site than when communities were compared across sites. In contrast, the identity of protozoans and metazoans in this community were similar in species identity both within a site and between the two sites, but abundances differed. Our results indicate that, at least during the beginning of succession, there is no strong selection for bacterial taxa and that there is no core group of bacteria required by the plant to start the decomposition of trapped insects. Co-evolution between the plant and bacteria appears to not have occurred as it has for other members of this community. PMID:23227224

Do fire and insects interact in eastern forests?

Treesearch

Lynne K. Rieske-Kinney

2006-01-01

The increasing use of prescribed fire as a management strategy for manipulating forest-species composition generates questions regarding the effects on the arthropod community and the underlying processes in which arthropods play a dominant role, as well as its potential as a pest suppression strategy. Despite the apparent benefits of prescribed burning for...

DNA extraction protocols cause differences in 16S rRNA amplicon sequencing efficiency but not in community profile composition or structure

DOE PAGES

None

2014-12-01

The recent development of methods applying next-generation sequencing to microbial community characterization has led to the proliferation of these studies in a wide variety of sample types. Yet, variation in the physical properties of environmental samples demands that optimal DNA extraction techniques be explored for each new environment. The microbiota associated with many species of insects offer an extraction challenge as they are frequently surrounded by an armored exoskeleton, inhibiting disruption of the tissues within. In this study, we examine the efficacy of several commonly used protocols for extracting bacterial DNA from ants. While bacterial community composition recovered using Illuminamore » 16S rRNA amplicon sequencing was not detectably biased by any method, the quantity of bacterial DNA varied drastically, reducing the number of samples that could be amplified and sequenced. These results indicate that the concentration necessary for dependable sequencing is around 10,000 copies of target DNA per microliter. Exoskeletal pulverization and tissue digestion increased the reliability of extractions, suggesting that these steps should be included in any study of insect-associated microorganisms that relies on obtaining microbial DNA from intact body segments. Although laboratory and analysis techniques should be standardized across diverse sample types as much as possible, minimal modifications such as these will increase the number of environments in which bacterial communities can be successfully studied.« less

Risk assessment of salinity and turbidity in Victoria (Australia) to stream insects' community structure does not always protect functional traits.

PubMed

Kefford, Ben J; Schäfer, Ralf B; Metzeling, Leon

2012-01-15

Ecological risk assessments mostly consider measures of community composition (structure) across large spatial scales. These assessments, using species sensitivity distributions (SSDs) or the relative species retention (RSR), may not be protective of ecosystem functions and services at smaller spatial scales. Here we examine how changes in biological traits, as proxy for ecosystem functions/services, at a fine spatial scale relate to larger scale assessment of structure. We use functional traits of stream insect species in south-east Australia in two habitats (riffle and edge/pool). We find that the protection of community structure in terms of 95% of species over multiple sites against adverse effects of salinity (as electrical conductivity) and turbidity will mostly, but not always, protect traits at smaller scales. Considering different combinations of trait modalities, contaminants and habitat, a mean of 17.5% (range 0%-36.8) of cases would result in under-protection of trait modalities despite protecting species composition (in terms of Jaccard's Index). This under-protection of trait modalities is only because of the different spatial scales that community structure and the traits were considered. We recommend that where the protection of biological traits, ecosystem functions or ecosystem services from stressors is a management goal, protective targets should not be solely set using measures of community structure such as SSDs or RSR. To protect both structural and functional attributes separate risk assessments should be done. Copyright © 2011 Elsevier B.V. All rights reserved.

Responses of community-level plant-insect interactions to climate warming in a meadow steppe.

PubMed

Zhu, Hui; Zou, Xuehui; Wang, Deli; Wan, Shiqiang; Wang, Ling; Guo, Jixun

2015-12-21

Climate warming may disrupt trophic interactions, consequently influencing ecosystem functioning. Most studies have concentrated on the temperature-effects on plant-insect interactions at individual and population levels, with a particular emphasis on changes in phenology and distribution. Nevertheless, the available evidence from the community level is limited. A 3-year field manipulative experiment was performed to test potential responses of plant and insect communities, and plant-insect interactions, to elevated temperature in a meadow steppe. Warming increased the biomass of plant community and forbs, and decreased grass biomass, indicating a shift from grass-dominant to grass-forb mixed plant community. Reduced abundance of the insect community under warming, particularly the herbivorous insects, was attributed to lower abundance of Euchorthippus unicolor and a Cicadellidae species resulting from lower food availability and higher defensive herbivory. Lower herbivore abundance caused lower predator species richness because of reduced prey resources and contributed to an overall decrease in insect species richness. Interestingly, warming enhanced the positive relationship between insect and plant species richness, implying that the strength of the plant-insect interactions was altered by warming. Our results suggest that alterations to plant-insect interactions at a community level under climate warming in grasslands may be more important and complex than previously thought.

Convergent bacterial microbiotas in the fungal agricultural systems of insects.

PubMed

Aylward, Frank O; Suen, Garret; Biedermann, Peter H W; Adams, Aaron S; Scott, Jarrod J; Malfatti, Stephanie A; Glavina del Rio, Tijana; Tringe, Susannah G; Poulsen, Michael; Raffa, Kenneth F; Klepzig, Kier D; Currie, Cameron R

2014-11-18

The ability to cultivate food is an innovation that has produced some of the most successful ecological strategies on the planet. Although most well recognized in humans, where agriculture represents a defining feature of civilization, species of ants, beetles, and termites have also independently evolved symbioses with fungi that they cultivate for food. Despite occurring across divergent insect and fungal lineages, the fungivorous niches of these insects are remarkably similar, indicating convergent evolution toward this successful ecological strategy. Here, we characterize the microbiota of ants, beetles, and termites engaged in nutritional symbioses with fungi to define the bacterial groups associated with these prominent herbivores and forest pests. Using culture-independent techniques and the in silico reconstruction of 37 composite genomes of dominant community members, we demonstrate that different insect-fungal symbioses that collectively shape ecosystems worldwide have highly similar bacterial microbiotas comprised primarily of the genera Enterobacter, Rahnella, and Pseudomonas. Although these symbioses span three orders of insects and two phyla of fungi, we show that they are associated with bacteria sharing high whole-genome nucleotide identity. Due to the fine-scale correspondence of the bacterial microbiotas of insects engaged in fungal symbioses, our findings indicate that this represents an example of convergence of entire host-microbe complexes. The cultivation of fungi for food is a behavior that has evolved independently in ants, beetles, and termites and has enabled many species of these insects to become ecologically important and widely distributed herbivores and forest pests. Although the primary fungal cultivars of these insects have been studied for decades, comparatively little is known of their bacterial microbiota. In this study, we show that diverse fungus-growing insects are associated with a common bacterial community composed of the same dominant members. Furthermore, by demonstrating that many of these bacteria have high whole-genome similarity across distantly related insect hosts that reside thousands of miles apart, we show that these bacteria are an important and underappreciated feature of diverse fungus-growing insects. Because of the similarities in the agricultural lifestyles of these insects, this is an example of convergence between both the life histories of the host insects and their symbiotic microbiota. Copyright © 2014 Aylward et al.

A multivariate test of disease risk reveals conditions leading to disease amplification.

PubMed

Halliday, Fletcher W; Heckman, Robert W; Wilfahrt, Peter A; Mitchell, Charles E

2017-10-25

Theory predicts that increasing biodiversity will dilute the risk of infectious diseases under certain conditions and will amplify disease risk under others. Yet, few empirical studies demonstrate amplification. This contrast may occur because few studies have considered the multivariate nature of disease risk, which includes richness and abundance of parasites with different transmission modes. By combining a multivariate statistical model developed for biodiversity-ecosystem-multifunctionality with an extensive field manipulation of host (plant) richness, composition and resource supply to hosts, we reveal that (i) host richness alone could not explain most changes in disease risk, and (ii) shifting host composition allowed disease amplification, depending on parasite transmission mode. Specifically, as predicted from theory, the effect of host diversity on parasite abundance differed for microbes (more density-dependent transmission) and insects (more frequency-dependent transmission). Host diversity did not influence microbial parasite abundance, but nearly doubled insect parasite abundance, and this amplification effect was attributable to variation in host composition. Parasite richness was reduced by resource addition, but only in species-rich host communities. Overall, this study demonstrates that multiple drivers, related to both host community and parasite characteristics, can influence disease risk. Furthermore, it provides a framework for evaluating multivariate disease risk in other systems. © 2017 The Author(s).

A global comparison of Bactericera cockerelli (Hemiptera: Triozidae) microbial communities.

PubMed

Arp, Alex; Munyaneza, Joseph E; Crosslin, James M; Trumble, John; Bextine, Blake

2014-04-01

The potato psyllid (Bactericera cockerelli Sulc) is an economically important insect pest of solanaceous crops such as potato, tomato, pepper, and tobacco. Historically, the potato psyllid's range included central United States, Mexico, and California; more recently, populations of this insect have been reported in Central America, the Pacific Northwest, and New Zealand. Like most phytophagous insects, potato psyllids require symbiotic bacteria to compensate for nutritional deficiencies in their diet. Potato psyllids harbor the primary symbiont, Candidatus Carsonella ruddii, and may also harbor many secondary symbionts such as Wolbachia sp., Sodalis sp., Pseudomonas sp., and others. These secondary symbionts can have an effect on reproduction, nutrition, immune response, and resistances to heat or pesticides. To identify regional differences in potato psyllid bacterial symbionts, 454 pyrosequencing was performed using generic 16S rRNA gene primers. Analysis was performed using the Qiime 1.6.0 software suite, ARB Silva, and R. Operational taxonomic units were then grouped at 97% identity. Representative sequences were classified to genus using the ARB SILVA database. Potato psyllids collected in California contained a less diverse microbial community than those collected in the central United States and Central America. The crop variety, collection year, and haplotype did not seem to affect the microbial community in potato psyllids. The primary difference between psyllids in different regions was the presence and overall bacterial community composition of Candidatus Carsonella ruddii and Wolbachia.

Intrinsic and extrinsic drivers of succession: Effects of habitat age and season on an aquatic insect community.

PubMed

Murrell, Ebony G; Ives, Anthony R; Juliano, Steven A

2014-06-01

1. Classical studies of succession, largely dominated by plant community studies, focus on intrinsic drivers of change in community composition, such as interspecific competition and changes to the abiotic environment. They often do not consider extrinsic drivers of colonization, such as seasonal phenology, that can affect community change. 2. We investigated both intrinsic and extrinsic drivers of succession for dipteran communities that occupy ephemeral pools, such as those in artificial containers. By initiating communities at different times in the season and following them over time, we compared the relative importance of intrinsic (i.e., habitat age) vs. extrinsic (i.e., seasonal phenology) drivers of succession. 3. We placed water-filled artificial containers in a deciduous forest with 20 containers initiated in each of three months. Containers were sampled weekly to assess community composition. Repeated-measures mixed-effects analysis of community correspondence analysis (CA) scores enabled us to partition intrinsic and extrinsic effects on succession. Covariates of temperature and precipitation were also tested. 4. Community trajectories (as defined by CA) differed significantly with habitat age and season, indicating that both intrinsic and extrinsic effects influence succession patterns. Comparisons of AICcs showed that habitat age was more important than season for species composition. Temperature and precipitation did not explain composition changes beyond those explained by habitat age and season. 5. Quantification of relative strengths of intrinsic and extrinsic effects on succession in dipteran and other ephemeral communities enables us to disentangle processes that must be understood for predicting changes in community composition.

Potential impacts of global warming on the diversity and distribution of stream insects in South Korea.

PubMed

Li, Fengqing; Kwon, Yong-Su; Bae, Mi-Jung; Chung, Namil; Kwon, Tae-Sung; Park, Young-Seuk

2014-04-01

Globally, the East Asian monsoon region is one of the richest environments in terms of biodiversity. The region is undergoing rapid human development, yet its river ecosystems have not been well studied. Global warming represents a major challenge to the survival of species in this region and makes it necessary to assess and reduce the potential consequences of warming on species of conservation concern. We projected the effects of global warming on stream insect (Ephemeroptera, Odonata, Plecoptera, and Trichoptera [EOPT]) diversity and predicted the changes of geographical ranges for 121 species throughout South Korea. Plecoptera was the most sensitive (decrease of 71.4% in number of species from the 2000s through the 2080s) order, whereas Odonata benefited (increase of 66.7% in number of species from the 2000s through the 2080s) from the effects of global warming. The impact of global warming on stream insects was predicted to be minimal prior to the 2060s; however, by the 2080s, species extirpation of up to 20% in the highland areas and 2% in the lowland areas were predicted. The projected responses of stream insects under global warming indicated that species occupying specific habitats could undergo major reductions in habitat. Nevertheless, habitat of 33% of EOPT (including two-thirds of Odonata and one-third of Ephemeroptera, Plecoptera, and Trichoptera) was predicted to increase due to global warming. The community compositions predicted by generalized additive models varied over this century, and a large difference in community structure in the highland areas was predicted between the 2000s and the 2080s. However, stream insect communities, especially Odonata, Plecoptera, and Trichoptera, were predicted to become more homogenous under global warming. © 2013 Society for Conservation Biology.

Long-term experimental warming alters community composition of ascomycetes in Alaskan moist and dry arctic tundra.

PubMed

Semenova, Tatiana A; Morgado, Luis N; Welker, Jeffrey M; Walker, Marilyn D; Smets, Erik; Geml, József

2015-01-01

Arctic tundra regions have been responding to global warming with visible changes in plant community composition, including expansion of shrubs and declines in lichens and bryophytes. Even though it is well known that the majority of arctic plants are associated with their symbiotic fungi, how fungal community composition will be different with climate warming remains largely unknown. In this study, we addressed the effects of long-term (18 years) experimental warming on the community composition and taxonomic richness of soil ascomycetes in dry and moist tundra types. Using deep Ion Torrent sequencing, we quantified how OTU assemblage and richness of different orders of Ascomycota changed in response to summer warming. Experimental warming significantly altered ascomycete communities with stronger responses observed in the moist tundra compared with dry tundra. The proportion of several lichenized and moss-associated fungi decreased with warming, while the proportion of several plant and insect pathogens and saprotrophic species was higher in the warming treatment. The observed alterations in both taxonomic and ecological groups of ascomycetes are discussed in relation to previously reported warming-induced shifts in arctic plant communities, including decline in lichens and bryophytes and increase in coverage and biomass of shrubs. © 2014 John Wiley & Sons Ltd.

Can soil microbial diversity influence plant metabolites and life history traits of a rhizophagous insect? A demonstration in oilseed rape.

PubMed

Lachaise, Tom; Ourry, Morgane; Lebreton, Lionel; Guillerm-Erckelboudt, Anne-Yvonne; Linglin, Juliette; Paty, Chrystelle; Chaminade, Valérie; Marnet, Nathalie; Aubert, Julie; Poinsot, Denis; Cortesero, Anne-Marie; Mougel, Christophe

2017-12-01

Interactions between plants and phytophagous insects play an important part in shaping the biochemical composition of plants. Reciprocally plant metabolites can influence major life history traits in these insects and largely contribute to their fitness. Plant rhizospheric microorganisms are an important biotic factor modulating plant metabolites and adaptation to stress. While plant-insects or plant-microorganisms interactions and their consequences on the plant metabolite signature are well-documented, the impact of soil microbial communities on plant defenses against phytophagous insects remains poorly known. In this study, we used oilseed rape (Brassica napus) and the cabbage root fly (Delia radicum) as biological models to tackle this question. Even though D. radicum is a belowground herbivore as a larva, its adult life history traits depend on aboveground signals. We therefore tested whether soil microbial diversity influenced emergence rate and fitness but also fly oviposition behavior, and tried to link possible effects to modifications in leaf and root metabolites. Through a removal-recolonization experiment, 3 soil microbial modalities ("high," "medium," "low") were established and assessed through amplicon sequencing of 16S and 18S ribosomal RNA genes. The "medium" modality in the rhizosphere significantly improved insect development traits. Plant-microorganism interactions were marginally associated to modulations of root metabolites profiles, which could partly explain these results. We highlighted the potential role of plant-microbial interaction in plant defenses against Delia radicum. Rhizospheric microbial communities must be taken into account when analyzing plant defenses against herbivores, being either below or aboveground. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Floral Visitors of Three Asteraceae Species in a Xeric Environment in Central Mexico.

PubMed

Figueroa-Castro, Dulce María; González-Tochihuitl, Guadalupe; Rivas-Arancibia, Sombra Patricia; Castaño-Meneses, Gabriela

2016-12-01

We describe the spatial variation in the structure and composition of the communities of insects visiting the inflorescences of Flaveria ramosissima Klatt, Florestina pedata (Cav.) Cass., and Parthenium bipinnatifidum (Ort.) Rollins (Asteraceae) in a xeric environment in Central Mexico. Inflorescences of the three Asteraceae were visited by a total of 96 species of Hymenoptera, Diptera, Lepidoptera, Coleoptera, and Hemiptera. Total species richness of floral visitors to the three Asteraceae and total abundance of insects of Fl. pedata and P. bipinnatifidum did not differ between low and high vegetation cover sites. Total abundance of insects visiting the inflorescences of F. ramosissima and abundance of Hymenoptera in all three Asteraceae were higher at the low vegetation coverage (LVC) site than at the high vegetation coverage (HVC) one. Diversity of insects of Fl. pedata and P. bipinnatifidum was higher at the HVC site. However, in F. ramosissima diversity was higher at the LVC site. The communities of insects of each Asteraceae were dissimilar between sites. These differences can be attributed to variation in the abundance of Lepidophora (Diptera: Bombyliidae), Miridae (Hemiptera), Melyridae (Coleoptera), Tiphiidae (Hymenoptera), Myrmecocystus mexicanus Wesmael, and Dorymyrmex grandulus (Forel) (Hymenoptera: Formicidae). The first three insect groups were sensitive to LVC, high temperature, and low humidity, whereas the last three tolerated those same environmental conditions. Changes in temperature, humidity, and resources associated with vegetation coverage seem to differentially affect each species of floral visitors of the three Asteraceae species studied. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Microbial Community Dynamics during Rearing of Black Soldier Fly Larvae (Hermetia illucens) and Impact on Exploitation Potential.

PubMed

De Smet, Jeroen; Wynants, Enya; Cos, Paul; Van Campenhout, Leen

2018-05-01

The need to increase sustainability in agriculture, to ensure food security for the future generations, is leading to the emergence of industrial rearing facilities for insects. One promising species being industrially reared as an alternative protein source for animal feed and as a raw material for the chemical industry is the black soldier fly ( Hermetia illucens ). However, scientific knowledge toward the optimization of the productivity for this insect is scarce. One knowledge gap concerns the impact of the microbial community associated with H. illucens on the performance and health of this insect. In this review, the first steps in the characterization of the microbiota in H. illucens and the analysis of substrate-dependent dynamics in its composition are summarized and discussed. Furthermore, this review zooms in on the interactions between microorganisms and the insect during H. illucens development. Finally, attention is paid to how the microbiome research can lead to alternative valorization strategies for H. illucens , such as (i) the manipulation of the microbiota to optimize insect biomass production and (ii) the exploitation of the H. illucens -microbiota interplay for the discovery of new enzymes and novel antimicrobial strategies based on H. illucens immunity using either the whole organism or its molecules. The next decade promises to be extremely interesting for this research field and will see an emergence of the microbiological optimization of H. illucens as a sustainable insect for industrial rearing and the exploitation of its microbiome for novel biotechnological applications. Copyright © 2018 American Society for Microbiology.

Organic farming favours insect-pollinated over non-insect pollinated forbs in meadows and wheat fields.

PubMed

Batáry, Péter; Sutcliffe, Laura; Dormann, Carsten F; Tscharntke, Teja

2013-01-01

The aim of this study was to determine the relative effects of landscape-scale management intensity, local management intensity and edge effect on diversity patterns of insect-pollinated vs. non-insect pollinated forbs in meadows and wheat fields. Nine landscapes were selected differing in percent intensively used agricultural area (IAA), each with a pair of organic and conventional winter wheat fields and a pair of organic and conventional meadows. Within fields, forbs were surveyed at the edge and in the interior. Both diversity and cover of forbs were positively affected by organic management in meadows and wheat fields. This effect, however, differed significantly between pollination types for species richness in both agroecosystem types (i.e. wheat fields and meadows) and for cover in meadows. Thus, we show for the first time in a comprehensive analysis that insect-pollinated plants benefit more from organic management than non-insect pollinated plants regardless of agroecosystem type and landscape complexity. These benefits were more pronounced in meadows than wheat fields. Finally, the community composition of insect-pollinated and non-insect-pollinated forbs differed considerably between management types. In summary, our findings in both agroecosystem types indicate that organic management generally supports a higher species richness and cover of insect-pollinated plants, which is likely to be favourable for the density and diversity of bees and other pollinators.

Organic Farming Favours Insect-Pollinated over Non-Insect Pollinated Forbs in Meadows and Wheat Fields

PubMed Central

Batáry, Péter; Sutcliffe, Laura; Dormann, Carsten F.; Tscharntke, Teja

2013-01-01

The aim of this study was to determine the relative effects of landscape-scale management intensity, local management intensity and edge effect on diversity patterns of insect-pollinated vs. non-insect pollinated forbs in meadows and wheat fields. Nine landscapes were selected differing in percent intensively used agricultural area (IAA), each with a pair of organic and conventional winter wheat fields and a pair of organic and conventional meadows. Within fields, forbs were surveyed at the edge and in the interior. Both diversity and cover of forbs were positively affected by organic management in meadows and wheat fields. This effect, however, differed significantly between pollination types for species richness in both agroecosystem types (i.e. wheat fields and meadows) and for cover in meadows. Thus, we show for the first time in a comprehensive analysis that insect-pollinated plants benefit more from organic management than non-insect pollinated plants regardless of agroecosystem type and landscape complexity. These benefits were more pronounced in meadows than wheat fields. Finally, the community composition of insect-pollinated and non-insect-pollinated forbs differed considerably between management types. In summary, our findings in both agroecosystem types indicate that organic management generally supports a higher species richness and cover of insect-pollinated plants, which is likely to be favourable for the density and diversity of bees and other pollinators. PMID:23382979

Natural vegetation cover in the landscape and edge effects: differential responses of insect orders in a fragmented forest.

PubMed

González, Ezequiel; Salvo, Adriana; Valladares, Graciela

2017-10-01

Human activities have led to global simplification of ecosystems, among which Neotropical dry forests are some of the most threatened. Habitat loss as well as edge effects may affect insect communities. Here, we analyzed insects sampled with pan traps in 9 landscapes (at 5 scales, in 100-500 m diameter circles) comprising cultivated fields and Chaco Serrano forests, at overall community and taxonomic order level. In total 7043 specimens and 456 species of hexapods were captured, with abundance and richness being directly related to forest cover at 500 m and higher at edges in comparison with forest interior. Community composition also varied with forest cover and edge/interior location. Different responses were detected among the 8 dominant orders. Collembola, Hemiptera, and Orthoptera richness and/or abundance were positively related to forest cover at the larger scale, while Thysanoptera abundance increased with forest cover only at the edge. Hymenoptera abundance and richness were negatively related to forest cover at 100 m. Coleoptera, Diptera, and Hymenoptera were more diverse and abundant at the forest edge. The generally negative influence of forest loss on insect communities could have functional consequences for both natural and cultivated systems, and highlights the relevance of forest conservation. Higher diversity at the edges could result from the simultaneous presence of forest and matrix species, although "resource mapping" might be involved for orders that were richer and more abundant at edges. Adjacent crops could benefit from forest proximity since natural enemies and pollinators are well represented in the orders showing positive edge effects. © 2016 Institute of Zoology, Chinese Academy of Sciences.

Transgenes sustain epigeal insect biodiversity in diversified vegetable farm systems.

PubMed

Leslie, T W; Hoheisel, G A; Biddinger, D J; Rohr, J R; Fleischer, S J

2007-02-01

Many ecological studies have focused on the effects of transgenes in field crops, but few have considered multiple transgenes in diversified vegetable systems. We compared the epigeal, or soil surface-dwelling, communities of Coleoptera and Formicidae between transgenic and isoline vegetable systems consisting of sweet corn, potato, and acorn squash, with transgenic cultivars expressing Cry1(A)b, Cry3, or viral coat proteins. Vegetables were grown in replicated split plots over 2 yr with integrated pest management (IPM) standards defining insecticide use patterns. More than 77.6% of 11,925 insects from 1,512 pitfall traps were identified to species, and activity density was used to compare dominance distribution, species richness, and community composition. Measures of epigeal biodiversity were always equal in transgenic vegetables, which required fewer insecticide applications than their near isolines. There were no differences in species richness between transgenic and isoline treatments at the farm system and individual crop level. Dominance distributions were also similar between transgenic and isoline farming systems. Crop type, and not genotype, had a significant influence on Carabidae and Staphylinidae community composition in the first year, but there were no treatment effects in the second year, possibly because of homogenizing effects of crop rotations. Communities were more influenced by crop type, and possibly crop rotation, than by genotype. The heterogeneity of crops and rotations in diversified vegetable farms seems to aid in preserving epigeal biodiversity, which may be supplemented by reductions in insecticide use associated with transgenic cultivars.

Change in soil fungal community structure driven by a decline in ectomycorrhizal fungi following a mountain pine beetle (Dendroctonus ponderosae) outbreak.

PubMed

Pec, Gregory J; Karst, Justine; Taylor, D Lee; Cigan, Paul W; Erbilgin, Nadir; Cooke, Janice E K; Simard, Suzanne W; Cahill, James F

2017-01-01

Western North American landscapes are rapidly being transformed by forest die-off caused by mountain pine beetle (Dendroctonus ponderosae), with implications for plant and soil communities. The mechanisms that drive changes in soil community structure, particularly for the highly prevalent ectomycorrhizal fungi in pine forests, are complex and intertwined. Critical to enhancing understanding will be disentangling the relative importance of host tree mortality from changes in soil chemistry following tree death. Here, we used a recent bark beetle outbreak in lodgepole pine (Pinus contorta) forests of western Canada to test whether the effects of tree mortality altered the richness and composition of belowground fungal communities, including ectomycorrhizal and saprotrophic fungi. We also determined the effects of environmental factors (i.e. soil nutrients, moisture, and phenolics) and geographical distance, both of which can influence the richness and composition of soil fungi. The richness of both groups of soil fungi declined and the overall composition was altered by beetle-induced tree mortality. Soil nutrients, soil phenolics and geographical distance influenced the community structure of soil fungi; however, the relative importance of these factors differed between ectomycorrhizal and saprotrophic fungi. The independent effects of tree mortality, soil phenolics and geographical distance influenced the community composition of ectomycorrhizal fungi, while the community composition of saprotrophic fungi was weakly but significantly correlated with the geographical distance of plots. Taken together, our results indicate that both deterministic and stochastic processes structure soil fungal communities following landscape-scale insect outbreaks and reflect the independent roles tree mortality, soil chemistry and geographical distance play in regulating the community composition of soil fungi. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Inferring the effects of potential dispersal routes on the metacommunity structure of stream insects: as the crow flies, as the fish swims or as the fox runs?

PubMed

Kärnä, Olli-Matti; Grönroos, Mira; Antikainen, Harri; Hjort, Jan; Ilmonen, Jari; Paasivirta, Lauri; Heino, Jani

2015-09-01

1. Metacommunity research relies largely on proxies for inferring the effect of dispersal on local community structure. Overland and watercourse distances have been typically used as such proxies. A good proxy for dispersal should, however, take into account more complex landscape features that can affect an organism's movement and dispersal. The cost distance approach does just that, allowing determining the path of least resistance across a landscape. 2. Here, we examined the distance decay of assemblage similarity within a subarctic stream insect metacommunity. We tested whether overland, watercourse and cumulative cost distances performed differently as correlates of dissimilarity in assemblage composition between sites. We also investigated the effect of body size and dispersal mode on metacommunity organization. 3. We found that dissimilarities in assemblage composition correlated more strongly with environmental than physical distances between sites. Overland and watercourse distances showed similar correlations to assemblage dissimilarity between sites, being sometimes significantly correlated with biological variation of entire insect communities. In metacommunities deconstructed by body size or dispersal mode, contrary to our expectation, passive dispersers showed a slightly stronger correlation than active dispersers to environmental differences between sites, although passive dispersers also showed a stronger correlation than active dispersers to physical distances between sites. The strength of correlation between environmental distance and biological dissimilarity also varied slightly among the body size classes. 4. After controlling for environmental differences between sites, cumulative cost distances were slightly better correlates of biological dissimilarities than overland or watercourse distances between sites. However, quantitative differences in correlation coefficients were small between different physical distances. 5. Although environmental differences typically override physical distances as determinants of the composition of stream insect assemblages, correlations between environmental distances and biological dissimilarities are typically rather weak. This undetermined variation may be attributable to dispersal processes, which may be captured using better proxies for the process. We suggest that further modifying the measurement of cost distances may be a fruitful avenue, especially if complemented by more direct natural history information on insect dispersal behaviour and distances travelled by them. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

Impact of environmental manipulation for Anopheles pseudopunctipennis Theobald control on aquatic insect communities in southern Mexico.

PubMed

Bond, J G; Quiroz-Martínez, H; Rojas, J C; Valle, J; Ulloa, A; Williams, T

2007-06-01

Extraction of filamentous algae from river pools is highly effective for the control of Anophelespseudopunctipennis in southern Mexico. We determined the magnitude of changes to the aquatic insect community following single annual perturbations performed over two years. In 2001, algae were manually removed from all the pools in a 3 km long section of the River Coatán, Mexico, while an adjacent section was left as an untreated control. In 2002, the treatments of both zones were switched and algal extraction was repeated. The abundance of An. pseudopunctipennis larvae + pupae was dramatically reduced by this treatment and remained depressed for two to three months. A total of 11,922 aquatic insects from ten orders, 40 families, and 95 genera were collected in monthly samples taken over five months of each year. Algal extraction did not reduce the overall abundance of aquatic insects in river pools, but a greater abundance and a greater richness of taxa were observed in 2002 compared to the previous year. This was associated with reduced precipitation and river discharge in 2002 compared to 2001. Shannon diversity index values were significantly depressed following algal extraction for a period of three months, in both years, before returning to values similar to those of the control zone. However, differences between years were greater than differences between treatments within a particular year. When insects were classified by functional feeding group (FFG), no significant differences were detected in FFG densities between extraction and control zones over time in either year of the study. Similarly, percent model affinity index values were classified as "not impacted" by the extraction process. Discriminant function analysis identified two orders of insects (Diptera and Odonata), water temperature, dissolved oxygen and conductivity, and river volume (depth, width, and discharge) as being of significant value in defining control and treatment groups in both years. We conclude that habitat manipulation represents an effective and environmentally benign strategy for control of An. pseduopunctipennis. Variation in precipitation and river discharge between years was much more important in determining aquatic insect community composition than variation generated by the filamentous algal extraction treatment.

Ecological modules and roles of species in heathland plant-insect flower visitor networks.

PubMed

Dupont, Yoko L; Olesen, Jens M

2009-03-01

1. Co-existing plants and flower-visiting animals often form complex interaction networks. A long-standing question in ecology and evolutionary biology is how to detect nonrandom subsets (compartments, blocks, modules) of strongly interacting species within such networks. Here we use a network analytical approach to (i) detect modularity in pollination networks, (ii) investigate species composition of modules, and (iii) assess the stability of modules across sites. 2. Interactions between entomophilous plants and their flower-visitors were recorded throughout the flowering season at three heathland sites in Denmark, separated by >or= 10 km. Among sites, plant communities were similar, but composition of flower-visiting insect faunas differed. Visitation frequencies of visitor species were recorded as a measure of insect abundance. 3. Qualitative (presence-absence) interaction networks were tested for modularity. Modules were identified, and species classified into topological roles (peripherals, connectors, or hubs) using 'functional cartography by simulated annealing', a method recently developed by Guimerà & Amaral (2005a). 4. All networks were significantly modular. Each module consisted of 1-6 plant species and 18-54 insect species. Interactions aggregated around one or two hub plant species, which were largely identical at the three study sites. 5. Insect species were categorized in taxonomic groups, mostly at the level of orders. When weighted by visitation frequency, each module was dominated by one or few insect groups. This pattern was consistent across sites. 6. Our study adds support to the conclusion that certain plant species and flower-visitor groups are nonrandomly and repeatedly associated. Within a network, these strongly interacting subgroups of species may exert reciprocal selection pressures on each other. Thus, modules may be candidates for the long-sought key units of co-evolution.

The carnivorous pale pitcher plant harbors diverse, distinct, and time-dependent bacterial communities.

PubMed

Koopman, Margaret M; Fuselier, Danielle M; Hird, Sarah; Carstens, Bryan C

2010-03-01

The ability of American carnivorous pitcher plants (Sarracenia) to digest insect prey is facilitated by microbial associations. Knowledge of the details surrounding this interaction has been limited by our capability to characterize bacterial diversity in this system. To describe microbial diversity within and between pitchers of one species, Sarracenia alata, and to explore how these communities change over time as pitchers accumulate and digest insect prey, we collected and analyzed environmental sequence tag (454 pyrosequencing) and genomic fingerprint (automated ribosomal intergenic spacer analysis and terminal restriction fragment length polymorphism) data. Microbial richness associated with pitcher plant fluid is high; more than 1,000 unique phylogroups were identified across at least seven phyla and 50 families. We documented an increase in bacterial diversity and abundance with time and observed repeated changes in bacterial community composition. Pitchers from different plants harbored significantly more similar bacterial communities at a given time point than communities coming from the same genetic host over time. The microbial communities in pitcher plant fluid also differ significantly from those present in the surrounding soil. These findings indicate that the bacteria associated with pitcher plant leaves are far from random assemblages and represent an important step toward understanding this unique plant-microbe interaction.

Forest litter insect community succession in clearcuts of Norway spruce

Treesearch

Arturas Gedminas

2003-01-01

Insects are subjected to stress in fresh clearcuts due to changes in microclimate, vegetation, and trophic links. The objective of this study was to investigate succession in litter insect communities (most abundant by number of species and individuals of all clearcut insects).

How low can you go? Impacts of a low-flow disturbance on aquatic insect communities.

PubMed

Walters, Annika W; Post, David M

2011-01-01

The natural hydrology of streams and rivers is being extensively modified by human activities. Water diversion, dam construction, and climate change have the potential to increase the frequency and intensity of low-flow events. Flow is a dominant force structuring stream aquatic insect communities, but the impacts of water diversion are poorly understood. Here we report results of an experimental stream flow diversion designed to test how aquatic insect communities respond to a low-flow disturbance. We diverted 40% to 80% of the water in three replicate streams for three summers, leading to summer flow exceedance probabilities of up to 99.9%. Shifts in habitat availability appeared to be a major driver of aquatic insect community responses. Responses also varied by habitat type: total insect density decreased in riffle habitats, but there was no change in pool habitats. Overall, the total biomass of aquatic insects decreased sharply with lowered flow. Collector-filterers, collector-gatherers, and scrapers were especially susceptible, while predatory insects were more resistant. Despite extremely low flow levels, there was no shift in aquatic insect family richness. The experimental water withdrawal did not increase water temperature or decrease water quality, and some wetted habitat was always maintained, which likely prevented more severe impacts on aquatic insect communities.

Convergent bacterial microbiotas in the fungal agricultural systems of insects

DOE PAGES

Aylward, Frank O.; Suen, Garret; Biedermann, Peter H. W.; ...

2014-11-18

The ability to cultivate food is an innovation that has produced some of the most successful ecological strategies on the planet. Although most well recognized in humans, where agriculture represents a defining feature of civilization, species of ants, beetles, and termites have also independently evolved symbioses with fungi that they cultivate for food. Despite occurring across divergent insect and fungal lineages, the fungivorous niches of these insects are remarkably similar, indicating convergent evolution toward this successful ecological strategy. Here, we characterize the microbiota of ants, beetles, and termites engaged in nutritional symbioses with fungi to define the bacterial groups associatedmore » with these prominent herbivores and forest pests. Using culture-independent techniques and the in silico reconstruction of 37 composite genomes of dominant community members, we demonstrate that different insect-fungal symbioses that collectively shape ecosystems worldwide have highly similar bacterial microbiotas comprised primarily of the genera Enterobacter, Rahnella, and Pseudomonas. Although these symbioses span three orders of insects and two phyla of fungi, we show that they are associated with bacteria sharing high whole-genome nucleotide identity. Due to the fine-scale correspondence of the bacterial microbiotas of insects engaged in fungal symbioses, our findings indicate that this represents an example of convergence of entire host-microbe complexes.« less

Convergent bacterial microbiotas in the fungal agricultural systems of insects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aylward, Frank O.; Suen, Garret; Biedermann, Peter H. W.

The ability to cultivate food is an innovation that has produced some of the most successful ecological strategies on the planet. Although most well recognized in humans, where agriculture represents a defining feature of civilization, species of ants, beetles, and termites have also independently evolved symbioses with fungi that they cultivate for food. Despite occurring across divergent insect and fungal lineages, the fungivorous niches of these insects are remarkably similar, indicating convergent evolution toward this successful ecological strategy. Here, we characterize the microbiota of ants, beetles, and termites engaged in nutritional symbioses with fungi to define the bacterial groups associatedmore » with these prominent herbivores and forest pests. Using culture-independent techniques and the in silico reconstruction of 37 composite genomes of dominant community members, we demonstrate that different insect-fungal symbioses that collectively shape ecosystems worldwide have highly similar bacterial microbiotas comprised primarily of the genera Enterobacter, Rahnella, and Pseudomonas. Although these symbioses span three orders of insects and two phyla of fungi, we show that they are associated with bacteria sharing high whole-genome nucleotide identity. Due to the fine-scale correspondence of the bacterial microbiotas of insects engaged in fungal symbioses, our findings indicate that this represents an example of convergence of entire host-microbe complexes.« less

Patterns of vegetation and grasshopper community composition.

PubMed

Kemp, W P; Harvey, S J; O'Neill, K M

1990-06-01

A study was conducted to evaluate differences in rangeland grasshopper communities over environmental gradients in Gallatin Valley, Montana, USA. The concept of habitat type (Daubenmire 1966) was used as a basis for discriminating between groupings of patches based on vegetation. A total of 39 patches were selected that represented five recognized grassland habitat types (Mueggler and Stewart 1980), as well as two disturbed types (replanting within a known habitat type). Repeated sampling in 1988 of both the insect and plant communities yielded a total of 40 grasshopper (19 664 individuals) and 97 plant species. Detrended Correspondence Analysis (DCA) indicated that patch classifications based on presence and percent cover of plants were appropriate and showed good between-group (habitat type) separation for patches along gradients of precipitation/elevation and plant community complexity. Results from undisturbed habitats showed that plant and grasshopper species composition changed over observed environmental gradients and suggested that habitat type influenced not only species presence, but also relative abundance. Discussion is presented that relates results with patch-use and core and satellite species paradigms.

The Carnivorous Pale Pitcher Plant Harbors Diverse, Distinct, and Time-Dependent Bacterial Communities▿ †

PubMed Central

Koopman, Margaret M.; Fuselier, Danielle M.; Hird, Sarah; Carstens, Bryan C.

2010-01-01

The ability of American carnivorous pitcher plants (Sarracenia) to digest insect prey is facilitated by microbial associations. Knowledge of the details surrounding this interaction has been limited by our capability to characterize bacterial diversity in this system. To describe microbial diversity within and between pitchers of one species, Sarracenia alata, and to explore how these communities change over time as pitchers accumulate and digest insect prey, we collected and analyzed environmental sequence tag (454 pyrosequencing) and genomic fingerprint (automated ribosomal intergenic spacer analysis and terminal restriction fragment length polymorphism) data. Microbial richness associated with pitcher plant fluid is high; more than 1,000 unique phylogroups were identified across at least seven phyla and 50 families. We documented an increase in bacterial diversity and abundance with time and observed repeated changes in bacterial community composition. Pitchers from different plants harbored significantly more similar bacterial communities at a given time point than communities coming from the same genetic host over time. The microbial communities in pitcher plant fluid also differ significantly from those present in the surrounding soil. These findings indicate that the bacteria associated with pitcher plant leaves are far from random assemblages and represent an important step toward understanding this unique plant-microbe interaction. PMID:20097807

Potential use of bacterial community succession for estimating post-mortem interval as revealed by high-throughput sequencing

PubMed Central

Guo, Juanjuan; Fu, Xiaoliang; Liao, Huidan; Hu, Zhenyu; Long, Lingling; Yan, Weitao; Ding, Yanjun; Zha, Lagabaiyila; Guo, Yadong; Yan, Jie; Chang, Yunfeng; Cai, Jifeng

2016-01-01

Decomposition is a complex process involving the interaction of both biotic and abiotic factors. Microbes play a critical role in the process of carrion decomposition. In this study, we analysed bacterial communities from live rats and rat remains decomposed under natural conditions, or excluding sarcosaphagous insect interference, in China using Illumina MiSeq sequencing of 16S rRNA gene amplicons. A total of 1,394,842 high-quality sequences and 1,938 singleton operational taxonomic units were obtained. Bacterial communities showed notable variation in relative abundance and became more similar to each other across body sites during the decomposition process. As decomposition progressed, Proteobacteria (mostly Gammaproteobacteria) became the predominant phylum in both the buccal cavity and rectum, while Firmicutes and Bacteroidetes in the mouth and rectum, respectively, gradually decreased. In particular, the arrival and oviposition of sarcosaphagous insects had no obvious influence on bacterial taxa composition, but accelerated the loss of biomass. In contrast to the rectum, the microbial community structure in the buccal cavity of live rats differed considerably from that of rats immediately after death. Although this research indicates that bacterial communities can be used as a “microbial clock” for the estimation of post-mortem interval, further work is required to better understand this concept. PMID:27052375

Predator community composition is linked to soil carbon retention across a human land use gradient.

PubMed

Schmitz, Oswald J; Buchkowski, Robert W; Smith, Jeffrey R; Telthorst, Mark; Rosenblatt, Adam E

2017-05-01

Soil carbon (C) storage is a major component of the carbon cycle. Consensus holds that soil C uptake and storage is regulated by plant-microbe-soil interactions. However, the contribution of animals in aboveground food webs to this process has been overlooked. Using insights from prior long-term experimentation in an old-field ecosystem and mathematical modeling, we predicted that the amount of soil C retention within a field should increase with the proportion of active hunting predators comprising the aboveground community of active hunting and sit-and-wait predators. This comes about because predators with different hunting modes have different cascading effects on plants. Our test of the prediction revealed that the composition of the arthropod predator community and associated cascading effects on the plant community explained 41% of variation in soil C retention among 15 old fields across a human land use gradient. We also evaluated the potential for several other candidate factors to explain variation in soil C retention among fields, independent of among-field variation in the predator community. These included live plant biomass, insect herbivore community composition, soil arthropod decomposer community composition, degree of land use development around the fields, field age, and soil texture. None of these candidate variables significantly explained soil C retention among the fields. The study offers a generalizable understanding of the pathways through which arthropod predator community composition can contribute to old-field ecosystem carbon storage. This insight helps support ongoing efforts to understand and manage the effects of anthropogenic land use change on soil C storage. © 2017 by the Ecological Society of America.

Insects: A nutritional alternative

NASA Technical Reports Server (NTRS)

Dufour, P. A.

1981-01-01

Insects are considered as potential food sources in space. Types of insects consumed are discussed. Hazards of insect ingestion are considered. Insect reproduction, requirements, and raw materials conversion are discussed. Nutrition properties and composition of insects are considered. Preparation of insects as human food is discussed.

Understanding the role of wildland fire, insects, and disease in predicting climate change effects on whitebark pine: Simulating vegetation, disturbance, and climate dynamics in a northern Rocky Mountain landscape

Treesearch

Robert Keane; Rachel Loehman

2010-01-01

Climate changes are projected to profoundly influence vegetation patterns and community compositions, either directly through increased species mortality and shifts in species distributions, or indirectly through disturbance dynamics such as increased wildfire activity and extent, shifting fire regimes, and pathogenesis. High-elevation landscapes have been shown to be...

Vulnerability of stream community composition and function to projected thermal warming and hydrologic change across ecoregions in the western United States.

PubMed

Pyne, Matthew I; Poff, N LeRoy

2017-01-01

Shifts in biodiversity and ecological processes in stream ecosystems in response to rapid climate change will depend on how numerically and functionally dominant aquatic insect species respond to changes in stream temperature and hydrology. Across 253 minimally perturbed streams in eight ecoregions in the western USA, we modeled the distribution of 88 individual insect taxa in relation to existing combinations of maximum summer temperature, mean annual streamflow, and their interaction. We used a heat map approach along with downscaled general circulation model (GCM) projections of warming and streamflow change to estimate site-specific extirpation likelihood for each taxon, allowing estimation of whole-community change in streams across these ecoregions. Conservative climate change projections indicate a 30-40% loss of taxa in warmer, drier ecoregions and 10-20% loss in cooler, wetter ecoregions where taxa are relatively buffered from projected warming and hydrologic change. Differential vulnerability of taxa with key functional foraging roles in processing basal resources suggests that climate change has the potential to modify stream trophic structure and function (e.g., alter rates of detrital decomposition and algal consumption), particularly in warmer and drier ecoregions. We show that streamflow change is equally as important as warming in projected risk to stream community composition and that the relative threat posed by these two fundamental drivers varies across ecoregions according to projected gradients of temperature and hydrologic change. Results also suggest that direct human modification of streams through actions such as water abstraction is likely to further exacerbate loss of taxa and ecosystem alteration, especially in drying climates. Management actions to mitigate climate change impacts on stream ecosystems or to proactively adapt to them will require regional calibration, due to geographic variation in insect sensitivity and in exposure to projected thermal warming and hydrologic change. © 2016 John Wiley & Sons Ltd.

Gut microbiota of Tenebrio molitor and their response to environmental change.

PubMed

Jung, Jaejoon; Heo, Aram; Park, Yong Woo; Kim, Ye Ji; Koh, Hyelim; Park, Woojun

2014-07-01

A bacterial community analysis of the gut of Tenebrio molitor larvae was performed using pyrosequencing of the 16S rRNA gene. A predominance of genus Spiroplasma species in phylum Tenericutes was observed in the gut samples, but there was variation found in the community composition between T. molitor individuals. The gut bacteria community structure was not significantly affected by the presence of antibiotics or by the exposure of T. molitor larvae to a highly diverse soil bacteria community. A negative relationship was identified between bacterial diversity and ampicillin concentration; however, no negative relationship was identified with the addition of kanamycin. Ampicillin treatment resulted in a reduction in the bacterial community size, estimated using the 16S rRNA gene copy number. A detailed phylogenetic analysis indicated that the Spiroplasma-associated sequences originating from the T. molitor larvae were distinct from previously identified Spiroplasma type species, implying the presence of novel Spiroplasma species. Some Spiroplasma species are known to be insect pathogens; however, the T. molitor larvae did not experience any harmful effects arising from the presence of Spiroplasma species, indicating that Spiroplasma in the gut of T. molitor larvae do not act as a pathogen to the host. A comparison with the bacterial communities found in other insects (Apis and Solenopsis) showed that the Spiroplasma species found in this study were specific to T. molitor.

Weed manipulation for insect pest management in corn

NASA Astrophysics Data System (ADS)

Altieri, M. A.; Whitcomb, W. H.

1980-11-01

Populations of insect pests and associated predaceous arthropods were sampled by direct observation and other relative methods in simple and diversified corn habitats at two sites in north Florida during 1978 and 1979. Through various cultural manipulations, characteristic weed communities were established selectively in alternate rows within corn plots. Fall armyworm ( Spodoptera frugiperda J. E. Smith) incidence was consistently higher in the weed-free habitats than in the corn habitats containing natural weed complexes or selected weed associations. Corn earworm ( Heliothis zea Boddie) damage was similar in all weed-free and weedy treatments, suggesting that this insect is not affected greatly by weed diversity. Only the diversification of corn with a strip of soybean significantly reduced corn earworm damage. In one site, distance between plots was reduced. Because predators moved freely between habitats, it was difficult to identify between-treatment differences in the composition of predator communities. In the other site, increased distances between plots minimized such migrations, resulting in greater population densities and diversity of common foliage insect predators in the weed-manipulated corn systems than in the weed-free plots. Trophic relationships in the weedy habitats were more complex than food webs in monocultures. Predator diversity (measured as mean number of species per area) and predator density was higher in com plots surrounded by mature, complex vegetation than at those surrounded by annual crops. This suggests that diverse adjacent areas to crops provide refuge for predators, thus acting as colonization sources.

Interactive effects of large herbivores and plant diversity on insect abundance in a meadow steppe in China

Treesearch

Hui Zhu; Deli Wang; Qinfeng Guo; Jun Liu; Ling Wang

2015-01-01

The structure and dynamics of insect community in grasslands can be influenced by grazing management via altered characteristics of plant community. However, attempts to better understand the complex relationships among plants, insects, and large herbivores is still hampered largely by the interactive effects of plants, insects, and large grazers on each other. In this...

Response of native insect communities to invasive plants.

PubMed

Bezemer, T Martijn; Harvey, Jeffrey A; Cronin, James T

2014-01-01

Invasive plants can disrupt a range of trophic interactions in native communities. As a novel resource they can affect the performance of native insect herbivores and their natural enemies such as parasitoids and predators, and this can lead to host shifts of these herbivores and natural enemies. Through the release of volatile compounds, and by changing the chemical complexity of the habitat, invasive plants can also affect the behavior of native insects such as herbivores, parasitoids, and pollinators. Studies that compare insects on related native and invasive plants in invaded habitats show that the abundance of insect herbivores is often lower on invasive plants, but that damage levels are similar. The impact of invasive plants on the population dynamics of resident insect species has been rarely examined, but invasive plants can influence the spatial and temporal dynamics of native insect (meta)populations and communities, ultimately leading to changes at the landscape level.

Aboveground insect herbivory increases plant competitive asymmetry, while belowground herbivory mitigates the effect

PubMed Central

Strengbom, Joachim; Viketoft, Maria; Bommarco, Riccardo

2016-01-01

Insect herbivores can shift the composition of a plant community, but the mechanism underlying such shifts remains largely unexplored. A possibility is that insects alter the competitive symmetry between plant species. The effect of herbivory on competition likely depends on whether the plants are subjected to aboveground or belowground herbivory or both, and also depends on soil nitrogen levels. It is unclear how these biotic and abiotic factors interactively affect competition. In a greenhouse experiment, we measured competition between two coexisting grass species that respond differently to nitrogen deposition: Dactylis glomerata L., which is competitively favoured by nitrogen addition, and Festuca rubra L., which is competitively favoured on nitrogen-poor soils. We predicted: (1) that aboveground herbivory would reduce competitive asymmetry at high soil nitrogen by reducing the competitive advantage of D. glomerata; and (2), that belowground herbivory would relax competition at low soil nitrogen, by reducing the competitive advantage of F. rubra. Aboveground herbivory caused a 46% decrease in the competitive ability of F. rubra, and a 23% increase in that of D. glomerata, thus increasing competitive asymmetry, independently of soil nitrogen level. Belowground herbivory did not affect competitive symmetry, but the combined influence of above- and belowground herbivory was weaker than predicted from their individual effects. Belowground herbivory thus mitigated the increased competitive asymmetry caused by aboveground herbivory. D. glomerata remained competitively dominant after the cessation of aboveground herbivory, showing that the influence of herbivory continued beyond the feeding period. We showed that insect herbivory can strongly influence plant competitive interactions. In our experimental plant community, aboveground insect herbivory increased the risk of competitive exclusion of F. rubra. Belowground herbivory appeared to mitigate the influence of aboveground herbivory, and this mechanism may play a role for plant species coexistence. PMID:27069805

Aboveground insect herbivory increases plant competitive asymmetry, while belowground herbivory mitigates the effect.

PubMed

Borgström, Pernilla; Strengbom, Joachim; Viketoft, Maria; Bommarco, Riccardo

2016-01-01

Insect herbivores can shift the composition of a plant community, but the mechanism underlying such shifts remains largely unexplored. A possibility is that insects alter the competitive symmetry between plant species. The effect of herbivory on competition likely depends on whether the plants are subjected to aboveground or belowground herbivory or both, and also depends on soil nitrogen levels. It is unclear how these biotic and abiotic factors interactively affect competition. In a greenhouse experiment, we measured competition between two coexisting grass species that respond differently to nitrogen deposition: Dactylis glomerata L., which is competitively favoured by nitrogen addition, and Festuca rubra L., which is competitively favoured on nitrogen-poor soils. We predicted: (1) that aboveground herbivory would reduce competitive asymmetry at high soil nitrogen by reducing the competitive advantage of D. glomerata; and (2), that belowground herbivory would relax competition at low soil nitrogen, by reducing the competitive advantage of F. rubra. Aboveground herbivory caused a 46% decrease in the competitive ability of F. rubra, and a 23% increase in that of D. glomerata, thus increasing competitive asymmetry, independently of soil nitrogen level. Belowground herbivory did not affect competitive symmetry, but the combined influence of above- and belowground herbivory was weaker than predicted from their individual effects. Belowground herbivory thus mitigated the increased competitive asymmetry caused by aboveground herbivory. D. glomerata remained competitively dominant after the cessation of aboveground herbivory, showing that the influence of herbivory continued beyond the feeding period. We showed that insect herbivory can strongly influence plant competitive interactions. In our experimental plant community, aboveground insect herbivory increased the risk of competitive exclusion of F. rubra. Belowground herbivory appeared to mitigate the influence of aboveground herbivory, and this mechanism may play a role for plant species coexistence.

Plant volatiles induced by herbivore egg deposition affect insects of different trophic levels.

PubMed

Fatouros, Nina E; Lucas-Barbosa, Dani; Weldegergis, Berhane T; Pashalidou, Foteini G; van Loon, Joop J A; Dicke, Marcel; Harvey, Jeffrey A; Gols, Rieta; Huigens, Martinus E

2012-01-01

Plants release volatiles induced by herbivore feeding that may affect the diversity and composition of plant-associated arthropod communities. However, the specificity and role of plant volatiles induced during the early phase of attack, i.e. egg deposition by herbivorous insects, and their consequences on insects of different trophic levels remain poorly explored. In olfactometer and wind tunnel set-ups, we investigated behavioural responses of a specialist cabbage butterfly (Pieris brassicae) and two of its parasitic wasps (Trichogramma brassicae and Cotesia glomerata) to volatiles of a wild crucifer (Brassica nigra) induced by oviposition of the specialist butterfly and an additional generalist moth (Mamestra brassicae). Gravid butterflies were repelled by volatiles from plants induced by cabbage white butterfly eggs, probably as a means of avoiding competition, whereas both parasitic wasp species were attracted. In contrast, volatiles from plants induced by eggs of the generalist moth did neither repel nor attract any of the tested community members. Analysis of the plant's volatile metabolomic profile by gas chromatography-mass spectrometry and the structure of the plant-egg interface by scanning electron microscopy confirmed that the plant responds differently to egg deposition by the two lepidopteran species. Our findings imply that prior to actual feeding damage, egg deposition can induce specific plant responses that significantly influence various members of higher trophic levels.

Local environment rather than past climate determines community composition of mountain stream macroinvertebrates across Europe.

PubMed

Múrria, Cesc; Bonada, Núria; Vellend, Mark; Zamora-Muñoz, Carmen; Alba-Tercedor, Javier; Sainz-Cantero, Carmen Elisa; Garrido, Josefina; Acosta, Raul; El Alami, Majida; Barquín, Jose; Derka, Tomáš; Álvarez-Cabria, Mario; Sáinz-Bariain, Marta; Filipe, Ana F; Vogler, Alfried P

2017-11-01

Community assembly is determined by a combination of historical events and contemporary processes that are difficult to disentangle, but eco-evolutionary mechanisms may be uncovered by the joint analysis of species and genetic diversity across multiple sites. Mountain streams across Europe harbour highly diverse macroinvertebrate communities whose composition and turnover (replacement of taxa) among sites and regions remain poorly known. We studied whole-community biodiversity within and among six mountain regions along a latitudinal transect from Morocco to Scandinavia at three levels of taxonomic hierarchy: genus, species and haplotypes. Using DNA barcoding of four insect families (>3100 individuals, 118 species) across 62 streams, we found that measures of local and regional diversity and intraregional turnover generally declined slightly towards northern latitudes. However, at all hierarchical levels we found complete (haplotype) or high (species, genus) turnover among regions (and even among sites within regions), which counters the expectations of Pleistocene postglacial northward expansion from southern refugia. Species distributions were mostly correlated with environmental conditions, suggesting a strong role of lineage- or species-specific traits in determining local and latitudinal community composition, lineage diversification and phylogenetic community structure (e.g., loss of Coleoptera, but not Ephemeroptera, at northern sites). High intraspecific genetic structure within regions, even in northernmost sites, reflects species-specific dispersal and demographic histories and indicates postglacial migration from geographically scattered refugia, rather than from only southern areas. Overall, patterns were not strongly concordant across hierarchical levels, but consistent with the overriding influence of environmental factors determining community composition at the species and genus levels. © 2017 John Wiley & Sons Ltd.

Environmental and ecological factors that shape the gut bacterial communities of fish: a meta-analysis

PubMed Central

Sullam, Karen E.; Essinger, Steven D.; Lozupone, Catherine A.; O’Connor, Michael P.; Rosen, Gail L.; Knight, Rob; Kilham, Susan S.; Russell, Jacob A.

2013-01-01

Symbiotic bacteria often help their hosts acquire nutrients from their diet, showing trends of co-evolution and independent acquisition by hosts from the same trophic levels. While these trends hint at important roles for biotic factors, the effects of the abiotic environment on symbiotic community composition remain comparably understudied. In this investigation, we examined the influence of abiotic and biotic factors on the gut bacterial communities of fish from different taxa, trophic levels and habitats. Phylogenetic and statistical analyses of 25 16S rRNA libraries revealed that salinity, trophic level and possibly host phylogeny shape the composition of fish gut bacteria. When analysed alongside bacterial communities from other environments, fish gut communities typically clustered with gut communities from mammals and insects. Similar consideration of individual phylotypes (vs. communities) revealed evolutionary ties between fish gut microbes and symbionts of animals, as many of the bacteria from the guts of herbivorous fish were closely related to those from mammals. Our results indicate that fish harbour more specialized gut communities than previously recognized. They also highlight a trend of convergent acquisition of similar bacterial communities by fish and mammals, raising the possibility that fish were the first to evolve symbioses resembling those found among extant gut fermenting mammals. PMID:22486918

A comparison of the beetle (Coleoptera) fauna captured at two heights above the ground in a North American temperate deciduous forest

Treesearch

Michael D. Ulyshen; James L. Hanula

2007-01-01

We compared the beetle fauna captured in 12 pairs of flight intercept traps suspended at two different heights above the ground ($15 m and 0.5 m) in a temperate deciduous forest in the southeastern United States to better understand how the abundance, species richness, diversity and composition of insect communities differ among forest strata. A total of 15,012 beetle...

A comparison of the Beetle (Coleoptera) Fauna Captured at two heights above the ground in a North American temperate deciduous forest

Treesearch

Michael Ulyshen; James Hanula

2007-01-01

We compared the beetle fauna captured in 12 pairs of flight intercept traps suspended at two different heights above the ground ($15 m and 0.5 m) in a temperate deciduous forest in the southeastern United States to better understand how the abundance, species richness, diversity and composition of insect communities differ among forest strata. A total of 15,012 beetle...

Effect of investigator disturbance in experimental forensic entomology: succession and community composition.

PubMed

De Jong, G D; Hoback, W W

2006-06-01

Carrion insect succession studies have historically used repeated sampling of single or a few carcasses to produce data, either weighing the carcasses, removing a qualitative subsample of the fauna present, or both, on every visit over the course of decomposition and succession. This study, conducted in a set of related experimental hypotheses with two trials in a single season, investigated the effect that repeated sampling has on insect succession, determined by the number of taxa collected on each visit and by community composition. Each trial lasted at least 21 days, with daily visits on the first 14 days. Rat carcasses used in this study were all placed in the field on the same day, but then either sampled qualitatively on every visit (similar to most succession studies) or ignored until a given day of succession, when they were sampled qualitatively (a subsample) and then destructively sampled in their entirety. Carcasses sampled on every visit were in two groups: those from which only a sample of the fauna was taken and those from which a sample of fauna was taken and the carcass was weighed for biomass determination. Of the carcasses visited only once, the number of taxa in subsamples was compared to the actual number of taxa present when the carcass was destructively sampled to determine if the subsamples adequately represented the total carcass fauna. Data from the qualitative subsamples of those carcasses visited only once were also compared to data collected from carcasses that were sampled on every visit to investigate the effect of the repeated sampling. A total of 39 taxa were collected from carcasses during the study and the component taxa are discussed individually in relation to their role in succession. Number of taxa differed on only one visit between the qualitative subsamples and the actual number of taxa present, primarily because the organisms missed by the qualitative sampling were cryptic (hidden deep within body cavities) or rare (only represented by very few specimens). There were no differences discovered between number of taxa in qualitative subsamples from carcasses sampled repeatedly (with or without biomass determinations) and those sampled only a single time. Community composition differed considerably in later stages of decomposition, with disparate communities due primarily to small numbers of rare taxa. These results indicate that the methods used historically for community composition determination in experimental forensic entomology are generally adequate.

Outbreaks by canopy-feeding geometrid moth cause state-dependent shifts in understorey plant communities.

PubMed

Karlsen, Stein Rune; Jepsen, Jane Uhd; Odland, Arvid; Ims, Rolf Anker; Elvebakk, Arve

2013-11-01

The increased spread of insect outbreaks is among the most severe impacts of climate warming predicted for northern boreal forest ecosystems. Compound disturbances by insect herbivores can cause sharp transitions between vegetation states with implications for ecosystem productivity and climate feedbacks. By analysing vegetation plots prior to and immediately after a severe and widespread outbreak by geometrid moths in the birch forest-tundra ecotone, we document a shift in forest understorey community composition in response to the moth outbreak. Prior to the moth outbreak, the plots divided into two oligotrophic and one eutrophic plant community. The moth outbreak caused a vegetation state shift in the two oligotrophic communities, but only minor changes in the eutrophic community. In the spatially most widespread communities, oligotrophic dwarf shrub birch forest, dominance by the allelopathic dwarf shrub Empetrum nigrum ssp. hermaphroditum, was effectively broken and replaced by a community dominated by the graminoid Avenella flexuosa, in a manner qualitatively similar to the effect of wild fires in E. nigrum communities in coniferous boreal forest further south. As dominance by E. nigrum is associated with retrogressive succession the observed vegetation state shift has widespread implications for ecosystem productivity on a regional scale. Our findings reveal that the impact of moth outbreaks on the northern boreal birch forest system is highly initial-state dependent, and that the widespread oligotrophic communities have a low resistance to such disturbances. This provides a case for the notion that climate impacts on arctic and northern boreal vegetation may take place most abruptly when conveyed by changed dynamics of irruptive herbivores.

Inbreeding alters volatile signalling phenotypes and influences tri-trophic interactions in horsenettle (Solanum carolinense L.).

PubMed

Kariyat, Rupesh R; Mauck, Kerry E; De Moraes, Consuelo M; Stephenson, Andrew G; Mescher, Mark C

2012-04-01

The ecological consequences of inter-individual variation in plant volatile emissions remain largely unexplored. We examined the effects of inbreeding on constitutive and herbivore-induced volatile emissions in horsenettle (Solanum carolinense L.) and on the composition of the insect community attracted to herbivore-damaged and undamaged plants in the field. Inbred plants exhibited higher constitutive emissions, but weaker induction of volatiles following herbivory. Moreover, many individual compounds previously implicated in the recruitment of predators and parasitoids (e.g. terpenes) were induced relatively weakly (or not at all) in inbred plants. In trapping experiments, undamaged inbred plants attracted greater numbers of generalist insect herbivores than undamaged outcrossed plants. But inbred plants recruited fewer herbivore natural enemies (predators and parasitoids) when damaged. Taken together, these findings suggest that inbreeding depression negatively impacts the overall pattern of volatile emissions - increasing the apparency of undamaged plants to herbivores, while reducing the recruitment of predatory insects to herbivore-damaged plants. © 2012 Blackwell Publishing Ltd/CNRS.

A review and meta-analysis of the enemy release hypothesis in plant–herbivorous insect systems

PubMed Central

Meijer, Kim; Schilthuizen, Menno; Beukeboom, Leo

2016-01-01

A suggested mechanism for the success of introduced non-native species is the enemy release hypothesis (ERH). Many studies have tested the predictions of the ERH using the community approach (native and non-native species studied in the same habitat) or the biogeographical approach (species studied in their native and non-native range), but results are highly variable, possibly due to large variety of study systems incorporated. We therefore focused on one specific system: plants and their herbivorous insects. We performed a systematic review and compiled a large number (68) of datasets from studies comparing herbivorous insects on native and non-native plants using the community or biogeographical approach. We performed a meta-analysis to test the predictions from the ERH for insect diversity (number of species), insect load (number of individuals) and level of herbivory for both the community and biogeographical approach. For both the community and biogeographical approach insect diversity was significantly higher on native than on non-native plants. Insect load tended to be higher on native than non-native plants at the community approach only. Herbivory was not different between native and non-native plants at the community approach, while there was too little data available for testing the biogeographical approach. Our meta-analysis generally supports the predictions from the ERH for both the community and biogeographical approach, but also shows that the outcome is importantly determined by the response measured and approach applied. So far, very few studies apply both approaches simultaneously in a reciprocal manner while this is arguably the best way for testing the ERH. PMID:28028463

COASTAL WETLAND INSECT COMMUNITIES ALONG A TROPHIC GRADIENT IN GREEN BAY, LAKE MICHIGAN

EPA Science Inventory

Insects of Great Lakes coastal wetlands have received little attention in spite of their importance in food webs and sensitivity to anthropogenic stressors. We characterized insect communities from four coastal wetlands that spanned the length of a trophic gradient in Green Bay d...

Bacterial communities associated with the pitcher fluids of three Nepenthes (Nepenthaceae) pitcher plant species growing in the wild.

PubMed

Chou, Lee Yiung; Clarke, Charles M; Dykes, Gary A

2014-10-01

Nepenthes pitcher plants produce modified jug-shaped leaves to attract, trap and digest insect prey. We used 16S rDNA cloning and sequencing to compare bacterial communities in pitcher fluids of each of three species, namely Nepenthes ampullaria, Nepenthes gracilis and Nepenthes mirabilis, growing in the wild. In contrast to previous greenhouse-based studies, we found that both opened and unopened pitchers harbored bacterial DNA. Pitchers of N. mirabilis had higher bacterial diversity as compared to other Nepenthes species. The composition of the bacterial communities could be different between pitcher types for N. mirabilis (ANOSIM: R = 0.340, p < 0.05). Other Nepenthes species had similar bacterial composition between pitcher types. SIMPER showed that more than 50 % of the bacterial taxa identified from the open pitchers of N. mirabilis were not found in other groups. Our study suggests that bacteria in N. mirabilis are divided into native and nonnative groups.

Spillover from adjacent crop and forest habitats shapes carabid beetle assemblages in fragmented semi-natural grasslands.

PubMed

Schneider, Gudrun; Krauss, Jochen; Boetzl, Fabian A; Fritze, Michael-Andreas; Steffan-Dewenter, Ingolf

2016-12-01

Semi-natural grasslands in Europe are insect biodiversity hotspots and important source habitats delivering ecosystem services to adjacent agricultural land by species spillover. However, this spillover might also occur in the opposite direction, affecting the diversity of semi-natural grasslands. This opposite spillover has got little attention in scientific literature even though generalist species penetrating into the grasslands can affect local biotic interactions, community composition and the conservation value of grassland habitats. In this study, we examined spillover effects from two different adjacent habitat types on carabid beetle assemblages in 20 semi-natural calcareous grasslands. The grasslands were either adjacent to a cereal crop field or to a coniferous forest. We found distinct differences in carabid beetle assemblages in calcareous grasslands depending on adjacent habitat type. Species richness and activity density were higher, but the evenness was lower in calcareous grasslands adjacent to crop fields compared with calcareous grasslands adjacent to coniferous forests. Further, we found a strong spillover of carabid beetles from adjacent crop fields after crop harvest, which may result in transiently increased predation pressure and resource competition in calcareous grasslands. Our results highlight that species composition, diversity and presumably ecosystem functions within semi-natural habitats are affected by the type and management of surrounding habitats. This needs to be considered by nature conservation measures, which aim to protect the unique insect communities of semi-natural European grasslands.

Social Insects Dominate Eastern US Temperate Hardwood Forest Macroinvertebrate Communities in Warmer Regions

PubMed Central

King, Joshua R.; Warren, Robert J.; Bradford, Mark A.

2013-01-01

Earthworms, termites, and ants are common macroinvertebrates in terrestrial environments, although for most ecosystems data on their abundance and biomass is sparse. Quantifying their areal abundance is a critical first step in understanding their functional importance. We intensively sampled dead wood, litter, and soil in eastern US temperate hardwood forests at four sites, which span much of the latitudinal range of this ecosystem, to estimate the abundance and biomass m−2 of individuals in macroinvertebrate communities. Macroinvertebrates, other than ants and termites, differed only slightly among sites in total abundance and biomass and they were similar in ordinal composition. Termites and ants were the most abundant macroinvertebrates in dead wood, and ants were the most abundant in litter and soil. Ant abundance and biomass m−2 in the southernmost site (Florida) were among the highest values recorded for ants in any ecosystem. Ant and termite biomass and abundance varied greatly across the range, from <1% of the total macroinvertebrate abundance (in the northern sites) to >95% in the southern sites. Our data reveal a pronounced shift to eusocial insect dominance with decreasing latitude in a temperate ecosystem. The extraordinarily high social insect relative abundance outside of the tropics lends support to existing data suggesting that ants, along with termites, are globally the most abundant soil macroinvertebrates, and surpass the majority of other terrestrial animal (vertebrate and invertebrate) groups in biomass m−2. Our results provide a foundation for improving our understanding of the functional role of social insects in regulating ecosystem processes in temperate forest. PMID:24116079

A call to insect scientists: Challenges and opportunities of managing insect communities under climate change

USGS Publications Warehouse

Hellmann, Jessica J.; Grundel, Ralph; Hoving, Chris; Schuurman, Gregor W.

2016-01-01

As climate change moves insect systems into uncharted territory, more knowledge about insect dynamics and the factors that drive them could enable us to better manage and conserve insect communities. Climate change may also require us revisit insect management goals and strategies and lead to a new kind of scientific engagement in management decision-making. Here we make five key points about the role of insect science in aiding and crafting management decisions, and we illustrate those points with the monarch butterfly and the Karner blue butterfly, two species undergoing considerable change and facing new management dilemmas. Insect biology has a strong history of engagement in applied problems, and as the impacts of climate change increase, a reimagined ethic of entomology in service of broader society may emerge. We hope to motivate insect biologists to contribute time and effort toward solving the challenges of climate change.

Reconstructing the pollinator community and predicting seed set from hydrocarbon footprints on flowers.

PubMed

Witjes, Sebastian; Witsch, Kristian; Eltz, Thomas

2011-04-01

The measurement of insect visits to flowers is essential for basic and applied pollination ecology, but is often fraught with difficulty. Floral visitation is highly variable and observational studies are limited in scope due to the considerable time needed to acquire reliable data. Our study investigates whether the analysis of hydrocarbon residues (footprints) deposited by insects during flower visits allows the reconstruction of the visitor community and the prediction of seed set for large numbers of plants. In three consecutive years we recorded bumblebee visitation to wild plants of comfrey, Symphytum officinale, and later used gas chromatography/mass spectrometry (GC/MS) to quantify bumblebee-derived unsaturated hydrocarbons (UHCs) extracted from flowers. The UHCs washed from corollae were most similar to the tarsal UHC profile of the most abundant bumblebee species, Bombus pascuorum, in all 3 years. The species compositions of the bumblebee communities estimated from UHCs on flowers were also similar to those actually observed. There was a significant positive correlation between the observed number of visits by each of three bumblebee species (contributing 3-68% of the flower visits) and the estimated number of visits based on UHC profiles. Furthermore, significant correlations were obtained separately for workers and drones of two species. Seed set of comfrey plants was positively correlated with overall bumblebee visitation and the total amount of UHCs on flowers, suggesting the potential for pollen limitation. We suggest that quantifying cumulative footprint hydrocarbons provides a novel way to assess floral visitation by insects, and that this method can be used to predict seed set in pollen-limited plants.

Hypoxia and hypercarbia in endophagous insects: Larval position in the plant gas exchange network is key.

PubMed

Pincebourde, Sylvain; Casas, Jérôme

2016-01-01

Gas composition is an important component of any micro-environment. Insects, as the vast majority of living organisms, depend on O2 and CO2 concentrations in the air they breathe. Low O2 (hypoxia), and high CO2 (hypercarbia) levels can have a dramatic effect. For phytophagous insects that live within plant tissues (endophagous lifestyle), gas is exchanged between ambient air and the atmosphere within the insect habitat. The insect larva contributes to the modification of this environment by expiring CO2. Yet, knowledge on the gas exchange network in endophagous insects remains sparse. Our study identified mechanisms that modulate gas composition in the habitat of endophagous insects. Our aim was to show that the mere position of the insect larva within plant tissues could be used as a proxy for estimating risk of occurrence of hypoxia and hypercarbia, despite the widely diverse life history traits of these organisms. We developed a conceptual framework for a gas diffusion network determining gas composition in endophagous insect habitats. We applied this framework to mines, galls and insect tunnels (borers) by integrating the numerous obstacles along O2 and CO2 pathways. The nature and the direction of gas transfers depended on the physical structure of the insect habitat, the photosynthesis activity as well as stomatal behavior in plant tissues. We identified the insect larva position within the gas diffusion network as a predictor of risk exposure to hypoxia and hypercarbia. We ranked endophagous insect habitats in terms of risk of exposure to hypoxia and/or hypercarbia, from the more to the less risky as cambium mines>borer tunnels≫galls>bark mines>mines in aquatic plants>upper and lower surface mines. Furthermore, we showed that the photosynthetically active tissues likely assimilate larval CO2 produced. In addition, temperature of the microhabitat and atmospheric CO2 alter gas composition in the insect habitat. We predict that (i) hypoxia indirectly favors the evolution of cold-tolerant gallers, which do not perform well at high temperatures, and (ii) normoxia (ambient O2 level) in mines allows miners to develop at high temperatures. Little is known, however, about physiological and morphological adaptations to hypoxia and hypercarbia in endophagous insects. Endophagy strongly constrains the diffusion processes with cascading consequences on the evolutionary ecology of endophagous insects. Copyright © 2015 Elsevier Ltd. All rights reserved.

Plant Volatiles Induced by Herbivore Egg Deposition Affect Insects of Different Trophic Levels

PubMed Central

Fatouros, Nina E.; Lucas-Barbosa, Dani; Weldegergis, Berhane T.; Pashalidou, Foteini G.; van Loon, Joop J. A.; Dicke, Marcel; Harvey, Jeffrey A.; Gols, Rieta; Huigens, Martinus E.

2012-01-01

Plants release volatiles induced by herbivore feeding that may affect the diversity and composition of plant-associated arthropod communities. However, the specificity and role of plant volatiles induced during the early phase of attack, i.e. egg deposition by herbivorous insects, and their consequences on insects of different trophic levels remain poorly explored. In olfactometer and wind tunnel set-ups, we investigated behavioural responses of a specialist cabbage butterfly (Pieris brassicae) and two of its parasitic wasps (Trichogramma brassicae and Cotesia glomerata) to volatiles of a wild crucifer (Brassica nigra) induced by oviposition of the specialist butterfly and an additional generalist moth (Mamestra brassicae). Gravid butterflies were repelled by volatiles from plants induced by cabbage white butterfly eggs, probably as a means of avoiding competition, whereas both parasitic wasp species were attracted. In contrast, volatiles from plants induced by eggs of the generalist moth did neither repel nor attract any of the tested community members. Analysis of the plant’s volatile metabolomic profile by gas chromatography-mass spectrometry and the structure of the plant-egg interface by scanning electron microscopy confirmed that the plant responds differently to egg deposition by the two lepidopteran species. Our findings imply that prior to actual feeding damage, egg deposition can induce specific plant responses that significantly influence various members of higher trophic levels. PMID:22912893

Exploring the Leaf Beetle Fauna (Coleoptera: Chrysomelidae) of an Ecuadorian Mountain Forest Using DNA Barcoding.

PubMed

Thormann, Birthe; Ahrens, Dirk; Marín Armijos, Diego; Peters, Marcell K; Wagner, Thomas; Wägele, Johann W

2016-01-01

Tropical mountain forests are hotspots of biodiversity hosting a huge but little known diversity of insects that is endangered by habitat destruction and climate change. Therefore, rapid assessment approaches of insect diversity are urgently needed to complement slower traditional taxonomic approaches. We empirically compare different DNA-based species delimitation approaches for a rapid biodiversity assessment of hyperdiverse leaf beetle assemblages along an elevational gradient in southern Ecuador and explore their effect on species richness estimates. Based on a COI barcode data set of 674 leaf beetle specimens (Coleoptera: Chrysomelidae) of 266 morphospecies from three sample sites in the Podocarpus National Park, we employed statistical parsimony analysis, distance-based clustering, GMYC- and PTP-modelling to delimit species-like units and compared them to morphology-based (parataxonomic) species identifications. The four different approaches for DNA-based species delimitation revealed highly similar numbers of molecular operational taxonomic units (MOTUs) (n = 284-289). Estimated total species richness was considerably higher than the sampled amount, 414 for morphospecies (Chao2) and 469-481 for the different MOTU types. Assemblages at different elevational levels (1000 vs. 2000 m) had similar species numbers but a very distinct species composition for all delimitation methods. Most species were found only at one elevation while this turnover pattern was even more pronounced for DNA-based delimitation. Given the high congruence of DNA-based delimitation results, probably due to the sampling structure, our study suggests that when applied to species communities on a regionally limited level with high amount of rare species (i.e. ~50% singletons), the choice of species delimitation method can be of minor relevance for assessing species numbers and turnover in tropical insect communities. Therefore, DNA-based species delimitation is confirmed as a valuable tool for evaluating biodiversity of hyperdiverse insect communities, especially when exact taxonomic identifications are missing.

Exploring the Leaf Beetle Fauna (Coleoptera: Chrysomelidae) of an Ecuadorian Mountain Forest Using DNA Barcoding

PubMed Central

Thormann, Birthe; Ahrens, Dirk; Marín Armijos, Diego; Peters, Marcell K.; Wagner, Thomas; Wägele, Johann W.

2016-01-01

Background Tropical mountain forests are hotspots of biodiversity hosting a huge but little known diversity of insects that is endangered by habitat destruction and climate change. Therefore, rapid assessment approaches of insect diversity are urgently needed to complement slower traditional taxonomic approaches. We empirically compare different DNA-based species delimitation approaches for a rapid biodiversity assessment of hyperdiverse leaf beetle assemblages along an elevational gradient in southern Ecuador and explore their effect on species richness estimates. Methodology/Principal Findings Based on a COI barcode data set of 674 leaf beetle specimens (Coleoptera: Chrysomelidae) of 266 morphospecies from three sample sites in the Podocarpus National Park, we employed statistical parsimony analysis, distance-based clustering, GMYC- and PTP-modelling to delimit species-like units and compared them to morphology-based (parataxonomic) species identifications. The four different approaches for DNA-based species delimitation revealed highly similar numbers of molecular operational taxonomic units (MOTUs) (n = 284–289). Estimated total species richness was considerably higher than the sampled amount, 414 for morphospecies (Chao2) and 469–481 for the different MOTU types. Assemblages at different elevational levels (1000 vs. 2000 m) had similar species numbers but a very distinct species composition for all delimitation methods. Most species were found only at one elevation while this turnover pattern was even more pronounced for DNA-based delimitation. Conclusions/Significance Given the high congruence of DNA-based delimitation results, probably due to the sampling structure, our study suggests that when applied to species communities on a regionally limited level with high amount of rare species (i.e. ~50% singletons), the choice of species delimitation method can be of minor relevance for assessing species numbers and turnover in tropical insect communities. Therefore, DNA-based species delimitation is confirmed as a valuable tool for evaluating biodiversity of hyperdiverse insect communities, especially when exact taxonomic identifications are missing. PMID:26849826

Evidence for the persistence of food web structure after amphibian extirpation in a Neotropical stream.

PubMed

Barnum, Thomas R; Drake, John M; Colón-Gaud, Checo; Rugenski, Amanda T; Frauendorf, Therese C; Connelly, Scott; Kilham, Susan S; Whiles, Matt R; Lips, Karen R; Pringle, Catherine M

2015-08-01

Species losses are predicted to simplify food web structure, and disease-driven amphibian declines in Central America offer an opportunity to test this prediction. Assessment of insect community composition, combined with gut content analyses, was used to generate periphyton-insect food webs for a Panamanian stream, both pre- and post-amphibian decline. We then used network analysis to assess the effects of amphibian declines on food web structure. Although 48% of consumer taxa, including many insect taxa, were lost between pre- and post-amphibian decline sampling dates, connectance declined by less than 3%. We then quantified the resilience of food web structure by calculating the number of expected cascading extirpations from the loss of tadpoles. This analysis showed the expected effects of species loss on connectance and linkage density to be more than 60% and 40%, respectively, than were actually observed. Instead, new trophic linkages in the post-decline food web reorganized the food web topology, changing the identity of "hub" taxa, and consequently reducing the effects of amphibian declines on many food web attributes. Resilience of food web attributes was driven by a combination of changes in consumer diets, particularly those of insect predators, as well as the appearance of generalist insect consumers, suggesting that food web structure is maintained by factors independent of the original trophic linkages.

Investigating effects of surrounding landscape composition and complexity on populations of two polyphagous insect pest groups in Iowa soybean

NASA Astrophysics Data System (ADS)

Kuntz, Cody Daniel

The composition and complexity of agro-ecosystems are important factors influencing the population dynamics of insect pests. Understanding these interactions may improve our ability to predict the spatial occurrence of pest outbreaks, thereby informing scouting and management decisions. In 2012 and 2013, two concurrent studies were conducted to examine the relationship between landscapes surrounding Iowa soybean, Glycine max [L.] Merrill, fields and two polyphagous pest groups; Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), and stink bugs (Hemiptera: Pentatomidae). Population densities were monitored in soybean within simple and complex agricultural landscapes to determine the response of these pests to landscape complexity. Results revealed P. japonica populations were significantly greater in soybean fields within complex landscapes and were positively associated with area of uncultivated land. The specific compositions of surrounding landscapes were also analyzed to determine the landscape features that explain the greatest variation in P. japonica and stink bug population densities. Results suggested that the area of wooded and grass habitat around fields accounted for the greatest variation in P. japonica populations; however, no discernable relationships were observed with stink bug populations. Sampling also sought to survey the community of stink bugs present in Iowa soybean. The community was predominantly comprised of stink bugs in the genus Euschistus, comprising a combined 91.04% of all captures. Additional species included the green stink bug, Acrosternum hilare (Say) (4.48%); spined soldier bug, Podisus maculiventris (Say) (2.99%); and red shouldered stink bug, Thyanta custator accerra (McAtee) (1.49%). Future work will be needed to determine if the landscape effects on P. japonica in soybean reported here are representative of other similar polyphagous pests of soybean and if they extend to other host plants as well. Furthermore, additional comprehensive surveys will be needed to better characterize the existing community of stink bug species present in Iowa field crops.

Influence of fruit and invertebrate consumption on the gut microbiota of wild white-faced capuchins (Cebus capucinus).

PubMed

Mallott, Elizabeth K; Amato, Katherine R; Garber, Paul A; Malhi, Ripan S

2018-03-01

Invertebrate consumption is thought to be an integral part of early hominin diets, and many modern human populations regularly consume insects and other arthropods. This study examines the response of gut microbial community structure and function to changes in diet in wild white-faced capuchins (Cebus capucinus), a primate that incorporates a large proportion of invertebrates in its diet. The goal of the study is to better understand the role of both fruit and invertebrate prey consumption on shaping primate gut microbiomes. Fecal samples (n = 169) and dietary data were collected over 12 months. The V3-V5 region of microbial 16S rRNA genes was amplified and sequenced. The IM-TORNADO pipeline was used to analyze sequences. White-faced capuchin gut bacterial communities were characterized primarily by Firmicutes (41.6%) and Proteobacteria (39.2%). There was a significant relationship between the invertebrate diet composition of individual capuchins and their gut microbiome composition. However, there was no relationship between the fruit diet composition of individual capuchins and their gut microbiome composition, even when examining multiple timescales. The results of our study indicate that there is a stronger relationship between gut microbial community structure and invertebrate diet composition than between gut microbial community structure and fruit consumption. As invertebrates and other animal prey play an important role in the diet of many primates, these results give important insight into the role of faunivory in shaping the evolution of host-microbe interactions in primates. © 2018 Wiley Periodicals, Inc.

The indirect impact of long-term overbrowsing on insects in the Allegheny National Forest region of Pennsylvania

Treesearch

Michael J. Chips; Ellen H. Yerger; Arpad Hervanek; Tim Nuttle; Alex Royo; Jonathan N. Pruitt; Terrence P. McGlynn; Cynthia L. Riggall; Walter P. Carson

2015-01-01

Overbrowsing has created depauperate plant communities throughout the eastern deciduous forest. We hypothesized these low-diversity plant communities are associated with lower insect diversity. We compared insects inside and outside a 60-year-old fenced deer exclosure where plant species richness is 5x higher inside versus outside. We sampled aboveground and litter...

The Core Gut Microbiome of the American Cockroach, Periplaneta americana, Is Stable and Resilient to Dietary Shifts.

PubMed

Tinker, Kara A; Ottesen, Elizabeth A

2016-11-15

The omnivorous cockroach Periplaneta americana hosts a diverse hindgut microbiota encompassing hundreds of microbial species. In this study, we used 16S rRNA gene sequencing to examine the effect of diet on the composition of the P. americana hindgut microbial community. Results show that the hindgut microbiota of P. americana exhibit a highly stable core microbial community with low variance in compositions between individuals and minimal community change in response to dietary shifts. This core hindgut microbiome is shared between laboratory-hosted and wild-caught individuals, although wild-caught specimens exhibited a higher diversity of low-abundance microbes that were lost following extended cultivation under laboratory conditions. This taxonomic stability strongly contrasts with observations of the gut microbiota of mammals, which have been shown to be highly responsive to dietary change. A comparison of P. americana hindgut samples with human fecal samples indicated that the cockroach hindgut community exhibited higher alpha diversity but a substantially lower beta diversity than the human gut microbiome. This suggests that cockroaches have evolved unique mechanisms for establishing and maintaining a diverse and stable core microbiome. The gut microbiome plays an important role in the overall health of its host. A healthy gut microbiota typically assists with defense against pathogens and the digestion and absorption of nutrients from food, while dysbiosis of the gut microbiota has been associated with reduced health. In this study, we examined the composition and stability of the gut microbiota from the omnivorous cockroach Periplaneta americana. We found that P. americana hosts a diverse core gut microbiome that remains stable after drastic long-term changes in diet. While other insects, notably ant and bee species, have evolved mechanisms for maintaining a stable association with specific gut microbiota, these insects typically host low-diversity gut microbiomes and consume specialized diets. In contrast, P. americana hosts a gut microbiota that is highly species rich and consumes a diverse solid diet, suggesting that cockroaches have evolved unique mechanisms for developing and maintaining a stable gut microbiota. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Community Dynamics of Carrion Flies and their Parasitoids in Experimental Carcasses in Central Argentina

PubMed Central

Horenstein, Moira Battán; Salvo, Adriana

2012-01-01

Insects are the predominant group regarding both species richness and abundance that develop on carrion. Among them, the most important decomposers using carrion as a source of food for their development are the immature stages of the dipteran families Calliphoridae, Muscidae, and Sarcophagidae. The large numbers of their larvae in carcasses are attacked by a rich community of parasitoids, including species of Braconidae, Ichneumonidae, and Pteromalidae (Hymenoptera: Parasitica). The objective of this study was describing the temporal composition and dynamics of a parasitoid community in relation to their dipterans hosts in carrion in terms of number of species and specific composition, irrespective of the particular interactions between species in both trophic levels. Additionally, seasonality of the climate in the region was investigated as a factor structuring the studied communities. The experiments were undertaken in the south of Cordoba, Argentina during 2004 in a rural area. Two traps per season were placed separately approximately 300 m from each other in the study site. Each trap contained a domestic pig (Sus scrofa) of approximately 8 kg as bait. Samples were taken daily during the first four weeks and then every two or three days over the following weeks until the end of the experiment. The dipteran community was represented by 15 species in 6 families of the Calyptratae Diptera whereas parasitoids belonged to six families of the parasitic Apocrita Hymenoptera. Climatic seasonality was an important factor in determining the number of occurring species in the carcasses and community composition. The highest number of species was observed in the spring for both communities. PMID:22963038

The Role of Dead Wood in Maintaining Arthropod Diversity on the Forest Floor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanula, James L.; Horn, Scott; Wade, Dale D.

2006-08-01

Dead wood is a major component of forests and contributes to overall diversity, primarily by supporting insects that feed directly on or in it. Further, a variety of organisms benefit by feeding on those insects. What is not well known is how or whether dead wood influences the composition of the arthropod community that is not solely dependent on it as a food resource, or whether woody debris influences prey available to generalist predators. One group likely to be affected by dead wood is ground-dwelling arthropods. We studied the effect of adding large dead wood to unburned and frequently burnedmore » pine stands to determine if dead wood was used more when the litter and understory plant community are removed. We also studied the effect of annual removal of dead wood from large (10-ha) plots over a 5-year period on ground-dwelling arthropods. In related studies, we examined the relationships among an endangered woodpecker that forages for prey on live trees, its prey, and dead wood in the forest. Finally, the results of these and other studies show that dead wood can influence the abundance and diversity of the ground-dwelling arthropod community and of prey available to generalist predators not foraging directly on dead trees.« less

Floral polymorphism and the fitness implications of attracting pollinating and florivorous insects.

PubMed

de Jager, Marinus L; Ellis, Allan G

2014-01-01

Floral polymorphism is frequently attributed to pollinator-mediated selection. Multiple studies, however, have revealed the importance of non-pollinating visitors in floral evolution. Using the polymorphic annual daisy Ursinia calenduliflora, this study investigated the importance of different insect visitors, and their effects on fitness, in the maintenance of floral polymorphism. The spatial structure of a discrete floral polymorphism was characterized based on the presence/absence of anthocyanin floret spots in U. calenduliflora. A 3-year observational study was then conducted in polymorphic populations to investigate differences in visitation rates of dominant visitors to floral morphs. Experiments were performed to explore the floral preference of male and female Megapalpus capensis (the dominant insect visitor) and their effectiveness as pollinators. Next, floral damage by antagonistic florivores and the reproductive success of the two floral morphs were surveyed in multiple populations and years. Floral polymorphism in U. calenduliflora was structured spatially, as were insect visitation patterns. Megapalpus capensis males were the dominant visitors and exhibited strong preference for the spotted morph in natural and experimental observations. While this may indicate potential fitness benefits for the spotted morph, female fitness did not differ between floral morphs. However, as M. capensis males are very efficient at exporting U. calenduliflora pollen, their preference may likely increase the reproductive fitness of the spotted morph through male fitness components. The spotted morph, however, also suffered significantly greater costs due to ovule predation by florivores than the spotless morph. The results suggest that pollinators and florivores may potentially exert antagonistic selection that could contribute to the maintenance of floral polymorphism across the range of U. calenduliflora. The relative strength of selection imposed by each agent is potentially determined by insect community composition and abundance at each site, highlighting the importance of community context in the evolution of floral phenotypes.

Bacteriome from Pinus arizonica and P. durangensis: Diversity, Comparison of Assemblages, and Overlapping Degree with the Gut Bacterial Community of a Bark Beetle That Kills Pines.

PubMed

Gonzalez-Escobedo, Roman; Briones-Roblero, Carlos I; Pineda-Mendoza, Rosa M; Rivera-Orduña, Flor N; Zúñiga, Gerardo

2018-01-01

Symbioses between plants and microorganims have been fundamental in the evolution of both groups. The endophytic bacteria associated with conifers have been poorly studied in terms of diversity, ecology, and function. Coniferous trees of the genera Larix , Pseudotsugae , Picea and mainly Pinus , are hosts of many insects, including bark beetles and especially the Dendroctonus species. These insects colonize and kill these trees during their life cycle. Several bacteria detected in the gut and cuticle of these insects have been identified as endophytes in conifers. In this study, we characterized and compared the endophytic bacterial diversity in roots, phloem and bark of non-attacked saplings of Pinus arizonica and P. durangensis using 16S rRNA gene pyrosequencing. In addition, we evaluated the degree of taxonomic relatedness, and the association of metabolic function profiles of communities of endophytic bacteria and previously reported gut bacterial communities of D. rhizophagus ; a specialized bark beetle that colonizes and kills saplings of these pine species. Our results showed that both pine species share a similar endophytic community. A total of seven bacterial phyla, 14 classes, 26 orders, 43 families, and 51 genera were identified. Enterobacteriaceae was the most abundant family across all samples, followed by Acetobacteraceae and Acidobacteriaceae, which agree with previous studies performed in other pines and conifers. Endophytic communities and that of the insect gut were significantly different, however, the taxonomic relatedness of certain bacterial genera of pines and insect assemblages suggested that some bacteria from pine tissues might be the same as those in the insect gut. Lastly, the metabolic profile using PICRUSt showed there to be a positive association between communities of both pines and insect gut. This study represents the baseline into the knowledge of the endophytic bacterial communities of two of the major hosts affected by D. rhizophagus .

Oviposition of aquatic insects in a tropical high altitude stream.

PubMed

Rios-Touma, Blanca; Encalada, A C; Prat, N

2012-12-01

The persistence of aquatic insect populations in streams depends on the recruitment of larval populations from egg masses deposited by adults, especially after disturbance. However, recruitment of aquatic populations by oviposition is a process that remains unstudied in streams and rivers. The objectives of our study were to document flying and oviposition patterns of aquatic insects in a high altitude tropical stream during both dry and wet seasons. In particular we studied 1) richness and abundance of adult forms of aquatic insects flying and ovipositing; 2) number of eggs (oviposition pattern), egg mass identity, and morphology; and 3) substrate preferences by ovipositing females. We found 2,383 aquatic insects corresponding to 28 families, with dipterans representing 89% of total individuals collected. Adult insects had lower richness (28 taxa) than larval diversity (up to 52 taxa) and distinct community composition. Richness and relative abundance of most taxa (adults) were not significantly different between seasons, behaviors, diel period, or all three. During both sampling periods we found females with eggs in a total of 15 different families (13 in the dry season and 14 in the wet season). There were no significant differences in the proportion of females with eggs between seasons, diel periods, or different behaviors (flying versus ovipositing traps) of the different female taxa. Few types of egg masses were found in rocks at the stream during both seasons, and most egg masses found corresponded to families Baetidae and Chironomidae. Finally, we provide the first description of eggs masses (size, shape, color, and number of eggs per female) of gravid females (10 taxa) and those found in the stream substrate (six taxa) of Andean macroinvertebrates. This is the first study reporting oviposition, adult diversity, and oviposition patterns of aquatic insects in the Andean region.

The role of mites in insect-fungus associations

Treesearch

R. W. Hofstetter; J. C. Moser

2014-01-01

The interactions among insects, mites, and fungi are diverse and complex but poorly understood in most cases. Associations among insects, mites, and fungi span an almost incomprehensible array of ecological interactions and evolutionary histories. Insects and mites often share habitats and resources and thus interact within communities. Many mites and insects rely on...

Climate Change and Tritrophic Interactions: Will Modifications to Greenhouse Gas Emissions Increase the Vulnerability of Herbivorous Insects to Natural Enemies?

PubMed

Boullis, Antoine; Francis, Frederic; Verheggen, François J

2015-04-01

Insects are highly dependent on odor cues released into the environment to locate conspecifics or food sources. This mechanism is particularly important for insect predators that rely on kairomones released by their prey to detect them. In the context of climate change and, more specifically, modifications in the gas composition of the atmosphere, chemical communication-mediating interactions between phytophagous insect pests, their host plants, and their natural enemies is likely to be impacted. Several reports have indicated that modifications to plants caused by elevated carbon dioxide and ozone concentrations might indirectly affect insect herbivores, with community-level modifications to this group potentially having an indirect influence on higher trophic levels. The vulnerability of agricultural insect pests toward their natural enemies under elevated greenhouse gases concentrations has been frequently reported, but conflicting results have been obtained. This literature review shows that the higher levels of carbon dioxide, as predicted for the coming century, do not enhance the abundance or efficiency of natural enemies to locate hosts or prey in most published studies. Increased ozone levels lead to modifications in herbivore-induced volatile organic compounds (VOCs) released by damaged plants, which may impact the attractiveness of these herbivores to the third trophic level. Furthermore, other oxidative gases (such as SO2 and NO2) tend to reduce the abundance of natural enemies. The impact of changes in atmospheric gas emissions on plant-insect and insect-insect chemical communication has been under-documented, despite the significance of these mechanisms in tritrophic interactions. We conclude by suggesting some further prospects on this topic of research yet to be investigated. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A Poorly Known High-Latitude Parasitoid Wasp Community: Unexpected Diversity and Dramatic Changes through Time

PubMed Central

Boudreault, Caroline; Goulet, Henri; Hebert, Paul D. N.; Smith, Adam C.

2011-01-01

Climate change will have profound and unanticipated effects on species distributions. The pace and nature of this change is largely unstudied, especially for the most diverse elements of terrestrial communities – the arthropods – here we have only limited knowledge concerning the taxonomy and the ecology of these groups. Because Arctic ecosystems have already experienced significant increases in temperature over the past half century, shifts in community structure may already be in progress. Here we utilise collections of a particularly hyperdiverse insect group – parasitoid wasps (Hymenoptera; Braconidae; Microgastrinae) – at Churchill, Manitoba, Canada in the early and mid-twentieth century to compare the composition of the contemporary community to that present 50–70 years ago. Morphological and DNA barcoding results revealed the presence of 79 species of microgastrine wasps in collections from Churchill, but we estimate that 20% of the local fauna awaits detection. Species composition and diversity between the two time periods differ significantly; species that were most common in historic collections were not found in contemporary collections and vice versa. Using barcodes we compared these collections to others from across North America; contemporary Churchill species are most affiliated with more south-western collections, while historic collections were more affiliated with eastern collections. The past five decades has clearly seen a dramatic change of species composition within the area studied coincident with rising temperature. PMID:21897854

Macronutrient contributions of insects to the diets of hunter-gatherers: a geometric analysis.

PubMed

Raubenheimer, David; Rothman, Jessica M; Pontzer, Herman; Simpson, Stephen J

2014-06-01

We present a geometric model for examining the macronutrient contributions of insects in the diets of pre-agricultural humans, and relate the findings to some contemporary societies that regularly eat insects. The model integrates published data on the macronutrient composition of insects and other foods in the diets of humans, recommended human macronutrient intakes, and estimated macronutrient intakes to examine the assumption that insects provided to pre-agricultural humans an invertebrate equivalent of vertebrate-derived meats, serving primarily as a source of protein. Our analysis suggests that insects vary more widely in their macronutrient content than is likely to be the case for most wild vertebrate meats, spanning a broad range of protein, fat and carbohydrate concentrations. Potentially, therefore, in terms of their proportional macronutrient composition, insects could serve as equivalents not only of wild meat, but of a range of other foods including some shellfish, nuts, pulses, vegetables and even fruits. Furthermore, humans might systematically manipulate the composition of edible insects to meet specific needs through pre-ingestive processing, such as cooking and selective removal of body parts. We present data suggesting that in modern societies for which protein is the more limiting macronutrient, pre-ingestive processing of edible insects might serve to concentrate protein. It is likely, however, that the dietary significance of insects was different for Paleolithic hunter-gatherers who were more limited in non-protein energy. Our conclusions are constrained by available data, but highlight the need for further studies, and suggest that our model provides an integrative framework for conceiving these studies. Copyright © 2014 Elsevier Ltd. All rights reserved.

Are edible insects more or less 'healthy' than commonly consumed meats? A comparison using two nutrient profiling models developed to combat over- and undernutrition.

PubMed

Payne, C L R; Scarborough, P; Rayner, M; Nonaka, K

2016-03-01

Insects have been the subject of recent attention as a potentially environmentally sustainable and nutritious alternative to traditional protein sources. The purpose of this paper is to test the hypothesis that insects are nutritionally preferable to meat, using two evaluative tools that are designed to combat over- and under-nutrition. We selected 183 datalines of publicly available data on the nutrient composition of raw cuts and offal of three commonly consumed meats (beef, pork and chicken), and six commercially available insect species, for energy and 12 relevant nutrients. We applied two nutrient profiling tools to this data: The Ofcom model, which is used in the United Kingdom, and the Nutrient Value Score (NVS), which has been used in East Africa. We compared the median nutrient profile scores of different insect species and meat types using non-parametric tests and applied Bonferroni adjustments to assess for statistical significance in differences. Insect nutritional composition showed high diversity between species. According to the Ofcom model, no insects were significantly 'healthier' than meat products. The NVS assigned crickets, palm weevil larvae and mealworm a significantly healthier score than beef (P<0.001) and chicken (P<0.001). No insects were statistically less healthy than meat. Insect nutritional composition is highly diverse in comparison with commonly consumed meats. The food category 'insects' contains some foods that could potentially exacerbate diet-related public health problems related to over-nutrition, but may be effective in combating under-nutrition.

Air pollutants degrade floral scents and increase insect foraging times

NASA Astrophysics Data System (ADS)

Fuentes, Jose D.; Chamecki, Marcelo; Roulston, T.'ai; Chen, Bicheng; Pratt, Kenneth R.

2016-09-01

Flowers emit mixtures of scents that mediate plant-insect interactions such as attracting insect pollinators. Because of their volatile nature, however, floral scents readily react with ozone, nitrate radical, and hydroxyl radical. The result of such reactions is the degradation and the chemical modification of scent plumes downwind of floral sources. Large Eddy Simulations (LES) are developed to investigate dispersion and chemical degradation and modification of floral scents due to reactions with ozone, hydroxyl radical, and nitrate radical within the atmospheric surface layer. Impacts on foraging insects are investigated by utilizing a random walk model to simulate insect search behavior. Results indicate that even moderate air pollutant levels (e.g., ozone mixing ratios greater than 60 parts per billion on a per volume basis, ppbv) substantially degrade floral volatiles and alter the chemical composition of released floral scents. As a result, insect success rates of locating plumes of floral scents were reduced and foraging times increased in polluted air masses due to considerable degradation and changes in the composition of floral scents. Results also indicate that plant-pollinator interactions could be sensitive to changes in floral scent composition, especially if insects are unable to adapt to the modified scentscape. The increase in foraging time could have severe cascading and pernicious impacts on the fitness of foraging insects by reducing the time devoted to other necessary tasks.

Eco-evolutionary processes affecting plant-herbivore interactions during early community succession.

PubMed

Howard, Mia M; Kalske, Aino; Kessler, André

2018-06-01

The quality and outcome of organismal interactions are not only a function of genotypic composition of the interacting species, but also the surrounding environment. Both the strength and direction of natural selection on interacting populations vary with the community context, which itself is changed by these interactions. Here, we test for the role of interacting evolutionary and ecological processes in plant-herbivore interactions during early community succession in the tall goldenrod, Solidago altissima. We use surveys in a large-scale field experiment with repeated plots representing 6 years of early oldfield succession and reciprocal transplant common garden experiments to test for the relative importance of rapid evolution (genetic) and environmental changes (soil quality) in affecting mean plant resistance and growth phenotypes during community succession. While plant growth varied strongly with soil quality over the first 5 years of agricultural abandonment, plant secondary metabolism, and herbivore resistance varied minimally with the soil environment. Instead, mean composition and abundance of plant secondary compound bouquets differed between S. altissima plants from populations collected in communities in the first ("early") and sixth ("intermediate") years of oldfield succession, which was reflected in the feeding preference of the specialist herbivore, Trirhabda virgata, for early succession lines. Moreover, this preference was most pronounced on poorer quality, early succession soils. Overall, our data demonstrate that plant quality varies for insect herbivores during the course of early succession and this change is a combination of altered genotypic composition of the population and phenotypic plasticity in different soil environments.

Review of food composition data for edible insects.

PubMed

Nowak, Verena; Persijn, Diedelinde; Rittenschober, Doris; Charrondiere, U Ruth

2016-02-15

Edible insects are considered rich in protein and a variety of micronutrients, and are therefore seen as potential contributors to food security. However, the estimation of the insects' contribution to the nutrient intake is limited since data are absent in food composition tables and databases. Therefore, FAO/INFOODS collected and published analytical data from primary sources with sufficient quality in the Food Composition Database for Biodiversity (BioFoodComp). Data were compiled for 456 food entries on insects in different developmental stages. A total of 5734 data points were entered, most on minerals and trace elements (34.8%), proximates (24.5%), amino acids (15.3%) and (pro)vitamins (9.1%). Data analysis of Tenebrio molitor confirms its nutritive quality that can help to combat malnutrition. The collection of data will assist compilers to incorporate more insects into tables and databases, and to further improve nutrient intake estimations. Copyright © 2015 Food and Agriculture Organization of the United Nations. Published by Elsevier Ltd.. All rights reserved.

The Effect of Host-Plant Phylogenetic Isolation on Species Richness, Composition and Specialization of Insect Herbivores: A Comparison between Native and Exotic Hosts

PubMed Central

Grandez-Rios, Julio Miguel; Lima Bergamini, Leonardo; Santos de Araújo, Walter; Villalobos, Fabricio; Almeida-Neto, Mário

2015-01-01

Understanding the drivers of plant-insect interactions is still a key issue in terrestrial ecology. Here, we used 30 well-defined plant-herbivore assemblages to assess the effects of host plant phylogenetic isolation and origin (native vs. exotic) on the species richness, composition and specialization of the insect herbivore fauna on co-occurring plant species. We also tested for differences in such effects between assemblages composed exclusively of exophagous and endophagous herbivores. We found a consistent negative effect of the phylogenetic isolation of host plants on the richness, similarity and specialization of their insect herbivore faunas. Notably, except for Jaccard dissimilarity, the effect of phylogenetic isolation on the insect herbivore faunas did not vary between native and exotic plants. Our findings show that the phylogenetic isolation of host plants is a key factor that influences the richness, composition and specialization of their local herbivore faunas, regardless of the host plant origin. PMID:26379159

Multiple Ant Species Tending Lac Insect Kerria yunnanensis (Hemiptera: Kerriidae) Provide Asymmetric Protection against Parasitoids

PubMed Central

Li, Qiao; Hoffmann, Benjamin D.; Zhang, Wei

2014-01-01

This study investigated the effects of ant attendance on the parasitoid community and parasitism of lac insect Kerria yunnanensis aggregations in Yunnan province, China. We manipulated ant attendance to establish three treatments: (1) ant exclusion; (2) low ant attendance by several ant species; and (3) high ant attendance by Crematogaster macaoensis. Five parasitoid species were collected, with two species contributing 82.7 and 13.2% of total abundance respectively. Total parasitoid abundance was lowest in the February sample when K. yunnanensis was in its younger life stage, being significantly lower in the ant exclusion treatment. In April, all three treatments had significantly different parasitoid abundances, being highest in the ant exclusion treatment and the lowest in the high ant attendance treatment. When ants were present, there were strong negative relationships between total parasitoid abundance and ant abundance, with the relationships being dependent upon the ant species composition and abundance. The patterns of total parasitoid abundance were driven by the two most abundant parasitoid species. Parasitoid species richness did not differ among treatments or between sample times, however, multivariate analysis confirmed that overall parasitoid community structure differed significantly among treatments and between sample times, with the high ant attendance treatment differing most from the other two treatments. Interestingly the absence of ants did not result in increased parasitism from four of the five parasitoids. Ants in lac insect farming systems have a clear role for agricultural pest management. A full understanding of the asymmetric abilities of ants to influence parasitoid communities, and affect parasitism of hosts will require further experimental manipulation to assess the relative roles of 1) the abundance of each individual ant species on parasitoid access to hosts, 2) competition among parasitoids, and 3) the interaction between the first two factors. PMID:24887398

Tropical Rainforest and Human-Modified Landscapes Support Unique Butterfly Communities That Differ in Abundance and Diversity.

PubMed

Sambhu, Hemchandranauth; Northfield, Tobin; Nankishore, Alliea; Ansari, Abdullah; Turton, Stephen

2017-12-08

Tropical forests account for at least 50% of documented diversity, but anthropogenic activities are converting forests to agriculture and urban areas at an alarming rate, with potentially strong effects on insect abundance and diversity. However, the questions remain whether insect populations are uniformly affected by land conversion and if insect conservation can occur in agricultural margins and urban gardens. We compare butterfly populations in tropical secondary forests to those found in sugarcane and urban areas in coastal Guyana and evaluate the potential for particular butterfly communities to inhabit human-modified landscapes. Butterflies were sampled for 1 yr using fruit-baited traps in three separated geographical locations on the coast. We used nonmetric multidimensional scaling to assess differences in species assemblages and a generalized linear mixed model to evaluate abundance, species richness, evenness, and diversity. The secondary forests in all three locations supported higher butterfly abundance and diversity than other human-modified areas, although the magnitude of this effect varied by season and location. However, each land use supported its own type of butterfly community, as species composition was different across the three land uses. Sugarcane field margins and urban gardens supported populations of butterflies rarely found in our tropical secondary forest sites. Land management practices that encourage forest conservation along with butterfly-friendly activities in human settlements and agricultural areas could improve butterfly conservation. To this end, butterfly conservation in Guyana and other tropical landscapes would benefit from a shift from inadvertently to actively making the landscape attractive for butterflies. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Deterministic Assembly of Complex Bacterial Communities in Guts of Germ-Free Cockroaches

PubMed Central

Mikaelyan, Aram; Thompson, Claire L.; Hofer, Markus J.

2015-01-01

The gut microbiota of termites plays important roles in the symbiotic digestion of lignocellulose. However, the factors shaping the microbial community structure remain poorly understood. Because termites cannot be raised under axenic conditions, we established the closely related cockroach Shelfordella lateralis as a germ-free model to study microbial community assembly and host-microbe interactions. In this study, we determined the composition of the bacterial assemblages in cockroaches inoculated with the gut microbiota of termites and mice using pyrosequencing analysis of their 16S rRNA genes. Although the composition of the xenobiotic communities was influenced by the lineages present in the foreign inocula, their structure resembled that of conventional cockroaches. Bacterial taxa abundant in conventional cockroaches but rare in the foreign inocula, such as Dysgonomonas and Parabacteroides spp., were selectively enriched in the xenobiotic communities. Donor-specific taxa, such as endomicrobia or spirochete lineages restricted to the gut microbiota of termites, however, either were unable to colonize germ-free cockroaches or formed only small populations. The exposure of xenobiotic cockroaches to conventional adults restored their normal microbiota, which indicated that autochthonous lineages outcompete foreign ones. Our results provide experimental proof that the assembly of a complex gut microbiota in insects is deterministic. PMID:26655763

Composition of forage and grain from second-generation insect-protected corn MON 89034 is equivalent to that of conventional corn (Zea mays L.).

PubMed

Drury, Suzanne M; Reynolds, Tracey L; Ridley, William P; Bogdanova, Natalia; Riordan, Susan; Nemeth, Margaret A; Sorbet, Roy; Trujillo, William A; Breeze, Matthew L

2008-06-25

Insect-protected corn hybrids containing Cry insecticidal proteins derived from Bacillus thuringiensis have protection from target pests and provide effective management of insect resistance. MON 89034 hybrids have been developed that produce both the Cry1A.105 and Cry2Ab2 proteins, which provide two independent modes of insecticidal action against the European corn borer ( Ostrinia nubilalis ) and other lepidopteran insect pests of corn. The composition of MON 89034 corn was compared to conventional corn by measuring proximates, fiber, and minerals in forage and by measuring proximates, fiber, amino acids, fatty acids, vitamins, minerals, antinutrients, and secondary metabolites in grain collected from 10 replicated field sites across the United States and Argentina during the 2004-2005 growing seasons. Analyses established that the forage and grain from MON 89034 are compositionally comparable to the control corn hybrid and conventional corn reference hybrids. These findings support the conclusion that MON 89034 is compositionally equivalent to conventional corn hybrids.

Death Becomes Them: Bacterial Community Dynamics and Stilbene Antibiotic Production in Cadavers of Galleria mellonella Killed by Heterorhabditis and Photorhabdus spp.

PubMed Central

Wollenberg, Amanda C.; Slough, Greg; Hoinville, Megan E.

2016-01-01

ABSTRACT Insect larvae killed by entomopathogenic nematodes are thought to contain bacterial communities dominated by a single bacterial genus, that of the nematode's bacterial symbiont. In this study, we used next-generation sequencing to profile bacterial community dynamics in greater wax moth (Galleria mellonella) larvae cadavers killed by Heterorhabditis nematodes and their Photorhabdus symbionts. We found that, although Photorhabdus strains did initially displace an Enterococcus-dominated community present in uninfected G. mellonella insect larvae, the cadaver community was not static. Twelve days postinfection, Photorhabdus shared the cadaver with Stenotrophomonas species. Consistent with this result, Stenotrophomonas strains isolated from infected cadavers were resistant to Photorhabdus-mediated toxicity in solid coculture assays. We isolated and characterized a Photorhabdus-produced antibiotic from G. mellonella cadavers, produced it synthetically, and demonstrated that both the natural and synthetic compounds decreased G. mellonella-associated Enterococcus growth, but not Stenotrophomonas growth, in vitro. Finally, we showed that the Stenotrophomonas strains described here negatively affected Photorhabdus growth in vitro. Our results add an important dimension to a broader understanding of Heterorhabditis-Photorhabdus biology and also demonstrate that interspecific bacterial competition likely characterizes even a theoretically monoxenic environment, such as a Heterorhabditis-Photorhabdus-parasitized insect cadaver. IMPORTANCE Understanding, and eventually manipulating, both human and environmental health depends on a complete accounting of the forces that act on and shape microbial communities. One of these underlying forces is hypothesized to be resource competition. A resource that has received little attention in the general microbiological literature, but likely has ecological and evolutionary importance, is dead/decaying multicellular organisms. Metazoan cadavers, including those of insects, are ephemeral and nutrient-rich environments, where resource competition might shape interspecific macrobiotic and microbiotic interactions. This study is the first to use a next-generation sequencing approach to study the community dynamics of bacteria within a model insect cadaver system: insect larvae parasitized by entomopathogenic nematodes and their bacterial symbionts. By integrating bioinformatic, biochemical, and classic in vitro microbiological approaches, we have provided mechanistic insight into how antibiotic-mediated bacterial interactions may shape community dynamics within insect cadavers. PMID:27451445

Influence of hydrological regime and land cover on traits and potential export capacity of adult aquatic insects from river channels.

PubMed

Greenwood, M J; Booker, D J

2016-02-01

Despite many studies highlighting the widespread occurrence and effects of resource movement between ecosystems, comparatively little is known about how anthropogenic alterations to ecosystems affect the strength, direction and importance of such fluxes. Hydrological regime and riparian land use cause well-documented changes in riverine larval invertebrate communities. Using a dataset from 66 sites collected over 20 years, we showed that such effects led to spatial and temporal differences in the density and type of larvae with winged adults within a river reach, altering the size and composition of the source pool from which adult aquatic insects can emerge. Mean annual larval densities varied 33-fold and the temporal range varied more than 20-fold between sites, associated with the hydrological regime and land cover and antecedent high and low flows, respectively. Densities of larvae with winged adults were greater in sites that had more algal coverage, agricultural land use, seasonally predictable flow regimes and faster water velocities. More interestingly, by influencing larval communities, riparian land use and the magnitude and frequency of high and low flows affected the size structure, dispersal ability and longevity of adults available to emerge from river reaches, potentially influencing the spatial extent and type of terrestrial consumers supported by aquatic prey. This suggests that anthropogenic alterations to land use or river flows will have both spatial and temporal effects on the flux and potential availability of adult aquatic insects to terrestrial consumers in many rivers.

Chemical composition of ground pearl (Eurhizococcus colombianus) cysts.

PubMed

Quiñones, Winston; Vicente, Bernardo; Torres, Fernando; Archbold, Rosendo; Murillo, Walter; Londoño, Martha; Echeverri, Fernando

2008-01-29

Ground pearl (Eurhizococcus colombianus) is a crop pest in Colombia, with special impact on fig, grass, rubus and tomato plants. The insect is resistant to external insecticide application because it produces a thick waxy shell that isolates it from the environment. The composition of this shell was determined by NMR and MS as a triglyceride, whose fatty acid is transformed into other products with the metamorphosis of the insect. Additionally, several enzymatic inhibitors were assayed to control the insect with negative results.

Defining the Insect Pollinator Community Found in Iowa Corn and Soybean Fields: Implications for Pollinator Conservation.

PubMed

Wheelock, M J; Rey, K P; O'Neal, M E

2016-10-01

Although corn (Zea mays L.) and soybeans (Glycine max L.) do not require pollination, they offer floral resources used by insect pollinators. We asked if a similar community of insect pollinators visits these crops in central Iowa, a landscape dominated by corn and soybean production. We used modified pan traps (i.e., bee bowls) in both corn and soybean fields during anthesis and used nonmetric multidimensional scaling (NMS) to compare the communities found in the two crops. Summed across both crops, 6,704 individual insects were captured representing at least 60 species, morphospecies, or higher-level taxa. Thirty-four species were collected in both crops, 19 collected only in corn and seven were collected only in soybean. The most abundant taxa were Lasioglossum [Dialictus] spp., Agapostemon virescens Cresson, Melissodes bimaculata (Lepeletier), and Toxomerus marginatus (Say), which accounted for 65% of the insect pollinators collected from both crops. Although social bees (Apis mellifera L. and Bombus spp.) were found in both crops, they accounted for only 0.5% of all insects captured. The NMS analysis revealed a shared community of pollinators composed of mostly solitary, ground nesting bees. Many of these species have been found in other crop fields throughout North America. Although corn and soybean are grown in landscapes that are often highly disturbed, these data suggest that a community of pollinators can persist within them. We suggest approaches to conserving this community based on partnering with activities that aim to lessen the environmental impact of annual crop production. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Herbivorous insect response to group selection cutting in a southeastern bottomland hardwood forest.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael D. Ulyshen; James L. Hanula; Scott Horn

2005-04-01

ABSTRACT Malaise and pitfall traps were used to sample herbivorous insects in canopy gaps created by group-selection cutting in a bottomland hardwood forest in South Carolina. The traps were placed at the centers, edges, and in the forest adjacent to gaps of different sizes (0.13, 0.26, and 0.50 ha) and ages (1 and 7 yr old) during four sampling periods in 2001. Overall, the abundance and species richness of insect herbivores were greater at the centers of young gaps than at the edge of young gaps or in the forest surrounding young gaps. There were no differences in abundance ormore » species richness among old gap locations (i.e., centers, edges, and forest), and we collected significantly more insects in young gaps than old gaps. The insect communities in old gaps were more similar to the forests surrounding them than young gap communities were to their respective forest locations, but the insect communities in the two forests locations (surrounding young and old gaps) had the highest percent similarity of all. Although both abundance and richness increased in the centers of young gaps with increasing gap size, these differences were not significant.Weattribute the increased numbers of herbivorous insects to the greater abundance of herbaceous plants available in young gaps.« less

Detection of Inter- and Intra-Specific Competition in the Insect Communities of British Trees: A Practical Exercise in Community Ecology.

ERIC Educational Resources Information Center

Putman, R. J.

1984-01-01

Describes an activity (suitable for high school or college) in which the effects of competition in the structuring of ecological communities are examined. The exercise also offers an introduction into species diversity; more advanced classes may be encouraged to seek reasons for differences in insect diversity on different trees. (Author/JN)

Flood Control Minnesota River, Minnesota, Minnesota, Mankato-North Mankato-Le Hillier, Design Memorandum Number 8. Part I. Location Study and Draft Supplement II to the Final Environmental Impact Statement for Bridge Relocations. Chicago and Northwestern Transportation Company Bridges Over the Blue Earth River between Mankato and Le Hillier.

DTIC Science & Technology

1981-04-01

230.4-1Cc) (2)) The composition of the biological community was sampled in the study area. The insect association is generally representative of a warm...be considered in discharge determination (40 CFR 230.5(a)) (1) Impacts on chemical, physical, and biological integrity of acuatic ecosystem (40 CFR

Phylogenetic composition of host plant communities drives plant-herbivore food web structure.

PubMed

Volf, Martin; Pyszko, Petr; Abe, Tomokazu; Libra, Martin; Kotásková, Nela; Šigut, Martin; Kumar, Rajesh; Kaman, Ondřej; Butterill, Philip T; Šipoš, Jan; Abe, Haruka; Fukushima, Hiroaki; Drozd, Pavel; Kamata, Naoto; Murakami, Masashi; Novotny, Vojtech

2017-05-01

Insects tend to feed on related hosts. The phylogenetic composition of host plant communities thus plays a prominent role in determining insect specialization, food web structure, and diversity. Previous studies showed a high preference of insect herbivores for congeneric and confamilial hosts suggesting that some levels of host plant relationships may play more prominent role that others. We aim to quantify the effects of host phylogeny on the structure of quantitative plant-herbivore food webs. Further, we identify specific patterns in three insect guilds with different life histories and discuss the role of host plant phylogeny in maintaining their diversity. We studied herbivore assemblages in three temperate forests in Japan and the Czech Republic. Sampling from a canopy crane, a cherry picker and felled trees allowed a complete census of plant-herbivore interactions within three 0·1 ha plots for leaf chewing larvae, miners, and gallers. We analyzed the effects of host phylogeny by comparing the observed food webs with randomized models of host selection. Larval leaf chewers exhibited high generality at all three sites, whereas gallers and miners were almost exclusively monophagous. Leaf chewer generality dropped rapidly when older host lineages (5-80 myr) were collated into a single lineage but only decreased slightly when the most closely related congeneric hosts were collated. This shows that leaf chewer generality has been maintained by feeding on confamilial hosts while only a few herbivores were shared between more distant plant lineages and, surprisingly, between some congeneric hosts. In contrast, miner and galler generality was maintained mainly by the terminal nodes of the host phylogeny and dropped immediately after collating congeneric hosts into single lineages. We show that not all levels of host plant phylogeny are equal in their effect on structuring plant-herbivore food webs. In the case of generalist guilds, it is the phylogeny of deeper plant lineages that drives the food web structure whereas the terminal relationships play minor roles. In contrast, the specialization and abundance of monophagous guilds are affected mainly by the terminal parts of the plant phylogeny and do not generally reflect deeper host phylogeny. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Spatial variation in the community of insects associated with the flowers of Pachycereus weberi (Caryophyllales: Cactaceae).

PubMed

Figueroa-Castro, Dulce María; Valverde, Pedro Luis; Vite, Fernando; Carrillo-Ruiz, Hortensia

2014-08-01

The positive relationship between productivity and species diversity is well-known. Insect communities associated with the flowers of Cactaceae species represent an interesting system to explore the productivity-diversity relationship because branches facing the equator receive more photosynthetically active radiation and have higher productivity. Thus, flowers with contrasting orientations within an individual, and even within a single branch, might differ in productivity. Therefore, higher abundance, species richness, and diversity are expected for the insect communities associated with south-facing flowers. This hypothesis was tested in Pachycereus weberi (J.M. Coulter) Backeberg (Cactaceae). Insects within flowers with contrasting orientations were collected and its abundance, richness, and diversity were estimated. We also asked if insects prefer big flowers. Thus, flower volume was estimated and regression analyses were conducted to test if there is a positive relationship between flower size and insect abundance. Flower orientation did not affect species richness. However, species abundance and diversity were different in flowers with contrasting orientations. In general, species abundance was higher in flowers facing southwards than in north-facing flowers. On the contrary, species diversity was higher in north-facing flowers. Abundance of Coleoptera was explained by flower volume in south-facing flowers. Contrary to our hypothesis, total diversity was greater in the less productive oriented flowers. Three possible explanations are discussed to explain the low diversity found in the highly productive, south-facing flowers. Our study provides evidence for the effects of productivity on the structure of insect communities at a very small-scale.

Host plant species determines symbiotic bacterial community mediating suppression of plant defenses

USDA-ARS?s Scientific Manuscript database

Herbivore associated bacteria are vital mediators of plant and insect interactions. Host plants play an important role in shaping the gut bacterial community of insects. Colorado potato beetles (CPB; Leptinotarsa decemlineata) use several Solanum plants as hosts in their natural environment. We prev...

A 2-Year Field Study Shows Little Evidence That the Long-Term Planting of Transgenic Insect-Resistant Cotton Affects the Community Structure of Soil Nematodes

PubMed Central

Li, Xiaogang; Liu, Biao

2013-01-01

Transgenic insect-resistant cotton has been released into the environment for more than a decade in China to effectively control the cotton bollworm (Helicoverpa armigera) and other Lepidoptera. Because of concerns about undesirable ecological side-effects of transgenic crops, it is important to monitor the potential environmental impact of transgenic insect-resistant cotton after commercial release. Our 2-year study included 1 cotton field where non-transgenic cotton had been planted continuously and 2 other cotton fields where transgenic insect-resistant cotton had been planted for different lengths of time since 1997 and since 2002. In 2 consecutive years (2009 and 2010), we took soil samples from 3 cotton fields at 4 different growth stages (seedling, budding, boll-forming and boll-opening stages), collected soil nematodes from soil with the sugar flotation and centrifugation method and identified the soil nematodes to the genus level. The generic composition, individual densities and diversity indices of the soil nematodes did not differ significantly between the 2 transgenic cotton fields and the non-transgenic cotton field, but significant seasonal variation was found in the individual densities of the principal trophic groups and in the diversity indices of the nematodes in all 3 cotton fields. The study used a comparative perspective to monitor the impact of transgenic insect-resistant cotton grown in typical ‘real world’ conditions. The results of the study suggested that more than 10 years of cultivation of transgenic insect-resistant cotton had no significant effects–adverse or otherwise–on soil nematodes. This study provides a theoretical basis for ongoing environmental impact monitoring of transgenic plants. PMID:23613899

Ant-caterpillar antagonism at the community level: interhabitat variation of tritrophic interactions in a neotropical savanna.

PubMed

Sendoya, Sebastián F; Oliveira, Paulo S

2015-03-01

Ant foraging on foliage can substantially affect how phytophagous insects use host plants and represents a high predation risk for caterpillars, which are important folivores. Ant-plant-herbivore interactions are especially pervasive in cerrado savanna due to continuous ant visitation to liquid food sources on foliage (extrafloral nectaries, insect honeydew). While searching for liquid rewards on plants, aggressive ants frequently attack or kill insect herbivores, decreasing their numbers. Because ants vary in diet and aggressiveness, their effect on herbivores also varies. Additionally, the differential occurrence of ant attractants (plant and insect exudates) on foliage produces variable levels of ant foraging within local floras and among localities. Here, we investigate how variation of ant communities and of traits among host plant species (presence or absence of ant attractants) can change the effect of carnivores (predatory ants) on herbivore communities (caterpillars) in a cerrado savanna landscape. We sampled caterpillars and foliage-foraging ants in four cerrado localities (70-460 km apart). We found that: (i) caterpillar infestation was negatively related with ant visitation to plants; (ii) this relationship depended on local ant abundance and species composition, and on local preference by ants for plants with liquid attractants; (iii) this was not related to local plant richness or plant size; (iv) the relationship between the presence of ant attractants and caterpillar abundance varied among sites from negative to neutral; and (v) caterpillars feeding on plants with ant attractants are more resistant to ant predation than those feeding on plants lacking attractants. Liquid food on foliage mediates host plant quality for lepidopterans by promoting generalized ant-caterpillar antagonism. Our study in cerrado shows that the negative effects of generalist predatory ants on herbivores are detectable at a community level, affecting patterns of abundance and host plant use by lepidopterans. The magnitude of ant-induced effects on caterpillar occurrence across the cerrado landscape may depend on how ants use plants locally and how they respond to liquid food on plants at different habitats. This study enhances the relevance of plant-ant and ant-herbivore interactions in cerrado and highlights the importance of a tritrophic perspective in this ant-rich environment. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

Microbial ecology of the salmon necrobiome: evidence salmon carrion decomposition influences aquatic and terrestrial insect microbiomes.

PubMed

Pechal, Jennifer L; Benbow, M Eric

2016-05-01

Carrion decomposition is driven by complex relationships that affect necrobiome community (i.e. all organisms and their genes associated with a dead animal) interactions, such as insect species arrival time to carrion and microbial succession. Little is understood about how microbial communities interact with invertebrates at the aquatic-terrestrial habitat interface. The first objective of the study was to characterize internal microbial communities using high-throughput sequencing of 16S rRNA gene amplicons for aquatic insects (three mayfly species) in streams with salmon carcasses compared with those in streams without salmon carcasses. The second objective was to assess the epinecrotic microbial communities of decomposing salmon carcasses (Oncorhynchus keta) compared with those of terrestrial necrophagous insects (Calliphora terraenovae larvae and adults) associated with the carcasses. There was a significant difference in the internal microbiomes of mayflies collected in salmon carcass-bearing streams and in non-carcass streams, while the developmental stage of blow flies was the governing factor in structuring necrophagous insect internal microbiota. Furthermore, the necrophagous internal microbiome was influenced by the resource on which the larvae developed, and changes in the adult microbiome varied temporally. Overall, these carrion subsidy-driven networks respond to resource pulses with bottom-up effects on consumer microbial structure, as revealed by shifting communities over space and time. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

Stiffness distribution in insect cuticle: a continuous or a discontinuous profile?

PubMed

Rajabi, H; Jafarpour, M; Darvizeh, A; Dirks, J-H; Gorb, S N

2017-07-01

Insect cuticle is a biological composite with a high degree of complexity in terms of both architecture and material composition. Given the complex morphology of many insect body parts, finite-element (FE) models play an important role in the analysis and interpretation of biomechanical measurements, taken by either macroscopic or nanoscopic techniques. Many previous studies show that the interpretation of nanoindentation measurements of this layered composite material is very challenging. To develop accurate FE models, it is of particular interest to understand more about the variations in the stiffness through the thickness of the cuticle. Considering the difficulties of making direct measurements, in this study, we use the FE method to analyse previously published data and address this issue numerically. For this purpose, sets of continuous or discontinuous stiffness profiles through the thickness of the cuticle were mathematically described. The obtained profiles were assigned to models developed based on the cuticle of three insect species with different geometries and layer configurations. The models were then used to simulate the mechanical behaviour of insect cuticles subjected to nanoindentation experiments. Our results show that FE models with discontinuous exponential stiffness gradients along their thickness were able to predict the stress and deformation states in insect cuticle very well. Our results further suggest that, for more accurate measurements and interpretation of nanoindentation test data, the ratio of the indentation depth to cuticle thickness should be limited to 7% rather than the traditional '10% rule'. The results of this study thus might be useful to provide a deeper insight into the biomechanical consequences of the distinct material distribution in insect cuticle and also to form a basis for more realistic modelling of this complex natural composite. © 2017 The Author(s).

Ecosystem Resilience and Limitations Revealed by Soil Bacterial Community Dynamics in a Bark Beetle-Impacted Forest

DOE PAGES

Mikkelson, Kristin M.; Brouillard, Brent M.; Bokman, Chelsea M.; ...

2017-12-05

ABSTRACT Forested ecosystems throughout the world are experiencing increases in the incidence and magnitude of insect-induced tree mortality with large ecologic ramifications. Interestingly, correlations between water quality and the extent of tree mortality in Colorado montane ecosystems suggest compensatory effects from adjacent live vegetation that mute responses in less severely impacted forests. To this end, we investigated whether the composition of the soil bacterial community and associated functionality beneath beetle-killed lodgepole pine was influenced by the extent of surrounding tree mortality. The most pronounced changes were observed in the potentially active bacterial community, where alpha diversity increased in concert withmore » surrounding tree mortality until mortality exceeded a tipping point of ~30 to 40%, after which diversity stabilized and decreased. Community structure also clustered in association with the extent of surrounding tree mortality with compositional trends best explained by differences in NH 4 + concentrations and C/N ratios. C/N ratios, which were lower in soils under beetle-killed trees, further correlated with the relative abundance of putative nitrifiers and exoenzyme activity. Collectively, the response of soil microorganisms that drive heterotrophic respiration and decay supports observations of broader macroscale threshold effects on water quality in heavily infested forests and could be utilized as a predictive mechanism during analogous ecosystem disruptions. IMPORTANCE Forests around the world are succumbing to insect infestation with repercussions for local soil biogeochemistry and downstream water quality and quantity. This study utilized microbial community dynamics to address why we are observing watershed scale biogeochemical impacts from forest mortality in some impacted areas but not others. Through a unique “tree-centric” approach, we were able to delineate plots with various tree mortality levels within the same watershed to see if surviving surrounding vegetation altered microbial and biogeochemical responses. Our results suggest that forests with lower overall tree mortality levels are able to maintain “normal” ecosystem function, as the bacterial community appears resistant to tree death. However, surrounding tree mortality influences this mitigating effect with various linear and threshold responses whereupon the bacterial community and its function are altered. Our study lends insight into how microscale responses propagate upward into larger-scale observations, which may be useful for future predictions during analogous disruptions.« less

Ecosystem Resilience and Limitations Revealed by Soil Bacterial Community Dynamics in a Bark Beetle-Impacted Forest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mikkelson, Kristin M.; Brouillard, Brent M.; Bokman, Chelsea M.

ABSTRACT Forested ecosystems throughout the world are experiencing increases in the incidence and magnitude of insect-induced tree mortality with large ecologic ramifications. Interestingly, correlations between water quality and the extent of tree mortality in Colorado montane ecosystems suggest compensatory effects from adjacent live vegetation that mute responses in less severely impacted forests. To this end, we investigated whether the composition of the soil bacterial community and associated functionality beneath beetle-killed lodgepole pine was influenced by the extent of surrounding tree mortality. The most pronounced changes were observed in the potentially active bacterial community, where alpha diversity increased in concert withmore » surrounding tree mortality until mortality exceeded a tipping point of ~30 to 40%, after which diversity stabilized and decreased. Community structure also clustered in association with the extent of surrounding tree mortality with compositional trends best explained by differences in NH 4 + concentrations and C/N ratios. C/N ratios, which were lower in soils under beetle-killed trees, further correlated with the relative abundance of putative nitrifiers and exoenzyme activity. Collectively, the response of soil microorganisms that drive heterotrophic respiration and decay supports observations of broader macroscale threshold effects on water quality in heavily infested forests and could be utilized as a predictive mechanism during analogous ecosystem disruptions. IMPORTANCE Forests around the world are succumbing to insect infestation with repercussions for local soil biogeochemistry and downstream water quality and quantity. This study utilized microbial community dynamics to address why we are observing watershed scale biogeochemical impacts from forest mortality in some impacted areas but not others. Through a unique “tree-centric” approach, we were able to delineate plots with various tree mortality levels within the same watershed to see if surviving surrounding vegetation altered microbial and biogeochemical responses. Our results suggest that forests with lower overall tree mortality levels are able to maintain “normal” ecosystem function, as the bacterial community appears resistant to tree death. However, surrounding tree mortality influences this mitigating effect with various linear and threshold responses whereupon the bacterial community and its function are altered. Our study lends insight into how microscale responses propagate upward into larger-scale observations, which may be useful for future predictions during analogous disruptions.« less

Ecosystem Resilience and Limitations Revealed by Soil Bacterial Community Dynamics in a Bark Beetle-Impacted Forest.

PubMed

Mikkelson, Kristin M; Brouillard, Brent M; Bokman, Chelsea M; Sharp, Jonathan O

2017-12-05

Forested ecosystems throughout the world are experiencing increases in the incidence and magnitude of insect-induced tree mortality with large ecologic ramifications. Interestingly, correlations between water quality and the extent of tree mortality in Colorado montane ecosystems suggest compensatory effects from adjacent live vegetation that mute responses in less severely impacted forests. To this end, we investigated whether the composition of the soil bacterial community and associated functionality beneath beetle-killed lodgepole pine was influenced by the extent of surrounding tree mortality. The most pronounced changes were observed in the potentially active bacterial community, where alpha diversity increased in concert with surrounding tree mortality until mortality exceeded a tipping point of ~30 to 40%, after which diversity stabilized and decreased. Community structure also clustered in association with the extent of surrounding tree mortality with compositional trends best explained by differences in NH 4 + concentrations and C/N ratios. C/N ratios, which were lower in soils under beetle-killed trees, further correlated with the relative abundance of putative nitrifiers and exoenzyme activity. Collectively, the response of soil microorganisms that drive heterotrophic respiration and decay supports observations of broader macroscale threshold effects on water quality in heavily infested forests and could be utilized as a predictive mechanism during analogous ecosystem disruptions. IMPORTANCE Forests around the world are succumbing to insect infestation with repercussions for local soil biogeochemistry and downstream water quality and quantity. This study utilized microbial community dynamics to address why we are observing watershed scale biogeochemical impacts from forest mortality in some impacted areas but not others. Through a unique "tree-centric" approach, we were able to delineate plots with various tree mortality levels within the same watershed to see if surviving surrounding vegetation altered microbial and biogeochemical responses. Our results suggest that forests with lower overall tree mortality levels are able to maintain "normal" ecosystem function, as the bacterial community appears resistant to tree death. However, surrounding tree mortality influences this mitigating effect with various linear and threshold responses whereupon the bacterial community and its function are altered. Our study lends insight into how microscale responses propagate upward into larger-scale observations, which may be useful for future predictions during analogous disruptions. Copyright © 2017 Mikkelson et al.

Agricultural applications of insect ecological genomics

USDA-ARS?s Scientific Manuscript database

Agricultural entomology is poised to benefit from the application of ecological genomics, in particular the fields of biofuels generation and pest insect control. Metagenomic methods can characterize microbial communities of termites, wood-boring beetles and other insects, and transcriptomic approa...

Cellulolytic Streptomyces Strains Associated with Herbivorous Insects Share a Phylogenetically Linked Capacity To Degrade Lignocellulose

PubMed Central

Book, Adam J.; Lewin, Gina R.; McDonald, Bradon R.; Takasuka, Taichi E.; Doering, Drew T.; Adams, Aaron S.; Blodgett, Joshua A. V.; Clardy, Jon; Raffa, Kenneth F.; Fox, Brian G.

2014-01-01

Actinobacteria in the genus Streptomyces are critical players in microbial communities that decompose complex carbohydrates in the soil, and these bacteria have recently been implicated in the deconstruction of plant polysaccharides for some herbivorous insects. Despite the importance of Streptomyces to carbon cycling, the extent of their plant biomass-degrading ability remains largely unknown. In this study, we compared four strains of Streptomyces isolated from insect herbivores that attack pine trees: DpondAA-B6 (SDPB6) from the mountain pine beetle, SPB74 from the southern pine beetle, and SirexAA-E (SACTE) and SirexAA-G from the woodwasp, Sirex noctilio. Biochemical analysis of secreted enzymes demonstrated that only two of these strains, SACTE and SDPB6, were efficient at degrading plant biomass. Genomic analyses indicated that SACTE and SDPB6 are closely related and that they share similar compositions of carbohydrate-active enzymes. Genome-wide proteomic and transcriptomic analyses revealed that the major exocellulases (GH6 and GH48), lytic polysaccharide monooxygenases (AA10), and mannanases (GH5) were conserved and secreted by both organisms, while the secreted endocellulases (GH5 and GH9 versus GH9 and GH12) were from diverged enzyme families. Together, these data identify two phylogenetically related insect-associated Streptomyces strains with high biomass-degrading activity and characterize key enzymatic similarities and differences used by these organisms to deconstruct plant biomass. PMID:24837391

Matrix Intensification Alters Avian Functional Group Composition in Adjacent Rainforest Fragments

PubMed Central

Deikumah, Justus P.; McAlpine, Clive A.; Maron, Martine

2013-01-01

Conversion of farmland land-use matrices to surface mining is an increasing threat to the habitat quality of forest remnants and their constituent biota, with consequences for ecosystem functionality. We evaluated the effects of matrix type on bird community composition and the abundance and evenness within avian functional groups in south-west Ghana. We hypothesized that surface mining near remnants may result in a shift in functional composition of avifaunal communities, potentially disrupting ecological processes within tropical forest ecosystems. Matrix intensification and proximity to the remnant edge strongly influenced the abundance of members of several functional guilds. Obligate frugivores, strict terrestrial insectivores, lower and upper strata birds, and insect gleaners were most negatively affected by adjacent mining matrices, suggesting certain ecosystem processes such as seed dispersal may be disrupted by landscape change in this region. Evenness of these functional guilds was also lower in remnants adjacent to surface mining, regardless of the distance from remnant edge, with the exception of strict terrestrial insectivores. These shifts suggest matrix intensification can influence avian functional group composition and related ecosystem-level processes in adjacent forest remnants. The management of matrix habitat quality near and within mine concessions is important for improving efforts to preserveavian biodiversity in landscapes undergoing intensification such as through increased surface mining. PMID:24058634

Matrix intensification alters avian functional group composition in adjacent rainforest fragments.

PubMed

Deikumah, Justus P; McAlpine, Clive A; Maron, Martine

2013-01-01

Conversion of farmland land-use matrices to surface mining is an increasing threat to the habitat quality of forest remnants and their constituent biota, with consequences for ecosystem functionality. We evaluated the effects of matrix type on bird community composition and the abundance and evenness within avian functional groups in south-west Ghana. We hypothesized that surface mining near remnants may result in a shift in functional composition of avifaunal communities, potentially disrupting ecological processes within tropical forest ecosystems. Matrix intensification and proximity to the remnant edge strongly influenced the abundance of members of several functional guilds. Obligate frugivores, strict terrestrial insectivores, lower and upper strata birds, and insect gleaners were most negatively affected by adjacent mining matrices, suggesting certain ecosystem processes such as seed dispersal may be disrupted by landscape change in this region. Evenness of these functional guilds was also lower in remnants adjacent to surface mining, regardless of the distance from remnant edge, with the exception of strict terrestrial insectivores. These shifts suggest matrix intensification can influence avian functional group composition and related ecosystem-level processes in adjacent forest remnants. The management of matrix habitat quality near and within mine concessions is important for improving efforts to preserveavian biodiversity in landscapes undergoing intensification such as through increased surface mining.

Ecosystem Resilience and Limitations Revealed by Soil Bacterial Community Dynamics in a Bark Beetle-Impacted Forest

PubMed Central

Brouillard, Brent M.; Bokman, Chelsea M.; Sharp, Jonathan O.

2017-01-01

ABSTRACT Forested ecosystems throughout the world are experiencing increases in the incidence and magnitude of insect-induced tree mortality with large ecologic ramifications. Interestingly, correlations between water quality and the extent of tree mortality in Colorado montane ecosystems suggest compensatory effects from adjacent live vegetation that mute responses in less severely impacted forests. To this end, we investigated whether the composition of the soil bacterial community and associated functionality beneath beetle-killed lodgepole pine was influenced by the extent of surrounding tree mortality. The most pronounced changes were observed in the potentially active bacterial community, where alpha diversity increased in concert with surrounding tree mortality until mortality exceeded a tipping point of ~30 to 40%, after which diversity stabilized and decreased. Community structure also clustered in association with the extent of surrounding tree mortality with compositional trends best explained by differences in NH4+ concentrations and C/N ratios. C/N ratios, which were lower in soils under beetle-killed trees, further correlated with the relative abundance of putative nitrifiers and exoenzyme activity. Collectively, the response of soil microorganisms that drive heterotrophic respiration and decay supports observations of broader macroscale threshold effects on water quality in heavily infested forests and could be utilized as a predictive mechanism during analogous ecosystem disruptions. PMID:29208740

Bacterial Community Composition Associated with Chironomid Egg Masses

PubMed Central

Senderovich, Yigal; Halpern, Malka

2012-01-01

Chironomids (Diptera: Chironomidae) are the most widely distributed and often the most abundant insect in freshwater. They undergo a complete metamorphosis of four life stages, of which the egg, larva, and pupae are aquatic and the adult is terrestrial. Chironomid egg masses were found to be natural reservoirs of Vibrio cholerae and Aeromonas species. To expand the knowledge of the endogenous bacterial community associated with chironomid egg masses, denaturing gradient gel electrophoresis and clone analysis of 16S rRNA gene libraries were used in this study. Bacterial community composition associated with chironomid egg masses was found to be stable among different sampling periods. Cloned libraries of egg masses revealed that about 40% of the clones were related to bacteria known to degrade various toxicants. These findings were further supported when bacterial species that showed resistance to different toxic metals were isolated from egg masses and larval samples. Chironomids are found under a wide range of water conditions and are able to survive pollutants. However, little is known about their protective mechanisms under these conditions. Chironomid egg masses are inhabited by a stable endogenous bacterial community, which may potentially play a role in protecting chironomids from toxicants in polluted environments. Further study is needed to support this hypothesis. PMID:23461272

Lessons from Studying Insect Symbioses

PubMed Central

Douglas, Angela E.

2011-01-01

As for mammals, insect health is strongly influenced by the composition and activities of resident microorganisms. However, the microbiota of insects is generally less diverse than that of mammals, allowing microbial function in insects to be coupled to individual, identified microbial species. This trait of insect symbioses facilitates our understanding of the mechanisms that promote insect-microbial coexistence and the processes by which the microbiota affect insect wellbeing. As a result, insects are potentially ideal models to study various aspects of interactions between the host and its resident microorganisms that are impractical or unfeasible in mammals and to generate hypotheses for subsequent testing in mammalian models. PMID:22018236

Survey for potential insect biological control agents of Ligustrum sinense (Scrophulariales: Oleaceae) in China.

Treesearch

Y-Z Zhang; J.L. Hanula; J. Sun

2008-01-01

A systematic survey of Chinese privet foliage, stems, seeds, and roots for associated phytophagous insects was conducted in China during 2005 and 2006 in order to establish basic information about the insect communities that Chinese privet harbors and to evaluate the abundance and damage caused by these insects. A total of 170...

Effects of predatory ants within and across ecosystems in bromeliad food webs.

PubMed

Gonçalves, Ana Z; Srivastava, Diane S; Oliveira, Paulo S; Romero, Gustavo Q

2017-07-01

Predation is one of the most fundamental ecological processes affecting biotic communities. Terrestrial predators that live at ecosystem boundaries may alter the diversity of terrestrial organisms, but they may also have cross-ecosystem cascading effects when they feed on organisms with complex life cycles (i.e. organisms that shift from aquatic juvenile stages to terrestrial adult stages) or inhibit female oviposition in the aquatic environment. The predatory ant Odontomachus hastatus establishes its colonies among roots of Vriesea procera, an epiphytic bromeliad species with water-filled tanks that shelters many terrestrial and aquatic organisms. Ants may impact terrestrial communities and deter adult insects from ovipositing in the water of bromeliads via consumptive and non-consumptive effects. Ants do not forage within the aquatic environment; thus, they may be more efficient predators on terrestrial organisms. Therefore, we predict that ants will have stronger effects on terrestrial than aquatic food webs. However, such effects may also be site contingent and depend on the local composition of food webs. To test our hypothesis, we surveyed bromeliads with and without O. hastatus colonies from three different coastal field sites in the Atlantic Forest of southeast Brazil, and quantified the effect of this predatory ant on the composition, density and richness of aquatic and terrestrial metazoans found in these bromeliads. We found that ants changed the composition and reduced the overall density of aquatic and terrestrial metazoans in bromeliad ecosystems. However, effects of ants on species diversity were contingent on site. In general terms, the effects of the ant on aquatic and terrestrial metazoan communities were similar in strength and magnitude. Ants reduced the density of virtually all aquatic functional groups, especially detritivore insects as well as metazoans that reach bromeliads through phoresy on the skin of terrestrial animals (i.e. Ostracoda and Helobdella sp.). Our results suggest that the cross-ecosystem effect of this terrestrial predator on the aquatic metazoans was at least as strong as its within-ecosystem effect on the terrestrial ecosystem, and demonstrates that the same predator can simultaneously initiate cascades in multiple ecosystems. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

Vertical stratification of beetles (Coleoptera) and flies (Diptera) in temperate forest canopies.

PubMed

Maguire, Dorothy Y; Robert, Katleen; Brochu, Kristen; Larrivée, Maxim; Buddle, Christopher M; Wheeler, Terry A

2014-02-01

Forest canopies support high arthropod biodiversity, but in temperate canopies, little is known about the spatial distribution of these arthropods. This is an important first step toward understanding ecological roles of insects in temperate canopies. The objective of this study was to assess differences in the species composition of two dominant and diverse taxa (Diptera and Coleoptera) along a vertical gradient in temperate deciduous forest canopies. Five sugar maple trees from each of three deciduous forest sites in southern Quebec were sampled using a combination of window and trunk traps placed in three vertical strata (understory, mid-canopy, and upper-canopy) for three sampling periods throughout the summer. Coleoptera species richness and abundance did not differ between canopy heights, but more specimens and species of Diptera were collected in the upper-canopy. Community composition of Coleoptera and Diptera varied significantly by trap height. Window traps collected more specimens and species of Coleoptera than trunk traps, although both trap types should be used to maximize representation of the entire Coleoptera community. There were no differences in abundance, diversity, or composition of Diptera collected between trap types. Our data confirm the relevance of sampling all strata in a forest when studying canopy arthropod biodiversity.

Plant Insecticidal Toxins in Ecological Networks

PubMed Central

Ibanez, Sébastien; Gallet, Christiane; Després, Laurence

2012-01-01

Plant secondary metabolites play a key role in plant-insect interactions, whether constitutive or induced, C- or N-based. Anti-herbivore defences against insects can act as repellents, deterrents, growth inhibitors or cause direct mortality. In turn, insects have evolved a variety of strategies to act against plant toxins, e.g., avoidance, excretion, sequestration and degradation of the toxin, eventually leading to a co-evolutionary arms race between insects and plants and to co-diversification. Anti-herbivore defences also negatively impact mutualistic partners, possibly leading to an ecological cost of toxin production. However, in other cases toxins can also be used by plants involved in mutualistic interactions to exclude inadequate partners and to modify the cost/benefit ratio of mutualism to their advantage. When considering the whole community, toxins have an effect at many trophic levels. Aposematic insects sequester toxins to defend themselves against predators. Depending on the ecological context, toxins can either increase insects’ vulnerability to parasitoids and entomopathogens or protect them, eventually leading to self-medication. We conclude that studying the community-level impacts of plant toxins can provide new insights into the synthesis between community and evolutionary ecology. PMID:22606374

Neotropical Amphibian Declines Affect Stream Ecosystem Properties

NASA Astrophysics Data System (ADS)

Connelly, S.; Pringle, C. M.; Bixby, R. J.; Whiles, M. R.; Lips, K. R.; Brenes, R.; Colon-Gaud, J. C.; Kilham, S.; Hunte-Brown, M.

2005-05-01

Global declines of amphibians are well documented, yet effects of these dramatic losses on ecosystem structure and function are poorly understood. As part of a larger collaborative project, we compared two upland Panamanian streams. Both streams are biologically and geologically similar; however, one stream (Fortuna) has recently experienced almost complete extirpation of stream-dwelling frogs, while the other (Cope) still has intact populations. We experimentally excluded tadpoles from localized areas in each stream. We then compared chlorophyll a, algal community composition, ash-free dry mass (AFDM), inorganic matter, and insect assemblages in control and exclusion areas. Additionally, we sampled the natural substrate of both streams monthly for chlorophyll a, algal community composition, AFDM, and inorganic matter. At Cope, chlorophyll a, AFDM, and inorganic matter were greater in areas where tadpoles were excluded than in their presence. Numbers of dominant algal species (e.g., Nupela praecipua and Eunotia siolii) were greater in the exclusion versus control treatments. Monthly sampling of natural substrate indicated higher chlorophyll a and AFDM at Cope compared to Fortuna. Our data suggest that stream-dwelling anuran larvae have significant impacts on algal communities. These results also have implications for predicting the relevance of short-term experimental manipulations to long-term, whole-stream processes.

Evolutionary escalation: the bat-moth arms race.

PubMed

Ter Hofstede, Hannah M; Ratcliffe, John M

2016-06-01

Echolocation in bats and high-frequency hearing in their insect prey make bats and insects an ideal system for studying the sensory ecology and neuroethology of predator-prey interactions. Here, we review the evolutionary history of bats and eared insects, focusing on the insect order Lepidoptera, and consider the evidence for antipredator adaptations and predator counter-adaptations. Ears evolved in a remarkable number of body locations across insects, with the original selection pressure for ears differing between groups. Although cause and effect are difficult to determine, correlations between hearing and life history strategies in moths provide evidence for how these two variables influence each other. We consider life history variables such as size, sex, circadian and seasonal activity patterns, geographic range and the composition of sympatric bat communities. We also review hypotheses on the neural basis for anti-predator behaviours (such as evasive flight and sound production) in moths. It is assumed that these prey adaptations would select for counter-adaptations in predatory bats. We suggest two levels of support for classifying bat traits as counter-adaptations: traits that allow bats to eat more eared prey than expected based on their availability in the environment provide a low level of support for counter-adaptations, whereas traits that have no other plausible explanation for their origination and maintenance than capturing defended prey constitute a high level of support. Specific predator counter-adaptations include calling at frequencies outside the sensitivity range of most eared prey, changing the pattern and frequency of echolocation calls during prey pursuit, and quiet, or 'stealth', echolocation. © 2016. Published by The Company of Biologists Ltd.

[Ecological fitness of transgenic GAFP cotton and its effects on the field insect community.

PubMed

Luo, Jun Yu; Zhang, Shuai; Zhu, Xiang Zhen; Lu, Li Min; Wang, Chun Yi; Li, Chun Hua; Zhang, Li Juan; Wang, Li; Cui, Jin Jie

2016-11-18

The ecological fitness of transgenic cotton and its effects on the insect communities in cotton fields is one of the key aspects of the evaluation of the environmental safety of transgenic cotton. New transgenic GAFP (Gastrodia anti-fungal protein) cotton and its parental varieties were used in this study to explore their ecological fitness and their effects on insect community infield in Anyang, Henan Province in 2013 and 2014. The results showed that there was no significant difference in dry mass for transgenic cotton leaves compared to that of parental cotton. Specific leaf areas of transgenic cotton were lowered obviously at seedling stage, while enhanced significantly at budding, flowering and bolling stages relative to parental cotton. The plant height of transgenic cotton was lowered only at seedling stage, and no significant difference was showed between the two cultivars at budding, flowering and bolling stages. No significant differences were discovered on plant branch numbers, bud numbers and falling numbers between the transgenic cotton and control material in any of the four key stages during the cotton growth. However, the number of bolls per plant for transgenic cotton was lower than that of the control cotton at the bolling stage. In the 2nd, 3rd, and 4th generation of cotton bollworm (Helicoverpa armigera), the mortality rate of cotton bollworm and beet armyworm (Spodoptera exigua) of transgenic cotton had no significant difference with parental cotton. Compared to parental cotton, total individuals of insect community, pest sub-communities and enemy sub-communities in transgenic cotton field didn't show any significant difference. The above results showed that after the GAFP gene was imported into cotton, the cotton growth was enhanced significantly, while the whole yield component traits and the insect community in the field were not significantly changed. Our study on the competition of new transgenic cotton and survival of transgenic cotton insect communities in cotton field would provide the theoretical basis for the evaluation of new transgenic cotton and environmental safety, and accumulate scientific data for environmental safety evaluation of the transgenic cotton.

Survey of phytophagous insects and foliar pathogens in China for a biocontrol perspective on kudzu, Pueraria montana var. lobata (Willd.) Maesen and S. Almeida (Fabaceae)

Treesearch

Jiang-Hua Sun; Zhu-Dong Liu; Ping Cai; David Orr; Judith Hough-Goldstein

2006-01-01

A three-year survey of kudzu foliage, seed, stems, and roots for associated phytophagous insects was conducted to establish basic information about the insect communities that kudzu harbors in China and to assess the abundance, diversity and damage caused by these insects. Diseases of kudzu were also surveyed in southern China. A total of 116 phytophagous insect...

Interspecific competition influences the organization of a diverse sessile insect community

NASA Astrophysics Data System (ADS)

Cornelissen, Tatiana; de Carvalho Guimarães, Carla Daniele; Rodrigues Viana, João Paulo; Silva, Bárbara

2013-10-01

Interspecific competition has played a major role in determining the effects of species interactions in terrestrial communities and the perception of its role on shaping population dynamics and community structure has changed throughout the years. In this study, we evaluated the existence of interspecific competition in the herbivore community of the dioecious plant Baccharis pseudomyriocephala (Asteraceae), which holds a diverse community of gall-forming insects. Sixty plants were studied and gall richness and abundance among plants were evaluated. To address whether a plant already occupied by a gall species is preferred or avoided by another gall species, null models were used for all 60 plants combined and for male and female plants separately. Our results have shown that the 11 species of gall-formers found on B. pseudomyriocephala co-occur less than expected by chance alone, indicating that interspecific competition might be an important force structuring the insect community in this tropical host plant, regardless of plant gender.

Baseline assessment of fish communities, benthic macroinvertebrate communities, and stream habitat and land use, Big Thicket National Preserve, Texas, 1999-2001

USGS Publications Warehouse

Moring, J. Bruce

2003-01-01

The Big Thicket National Preserve comprises 39,300 hectares in the form of nine preserve units connected by four stream corridor units (with two more corridor units proposed) distributed over the lower Neches and Trinity River Basins of southeastern Texas. Fish and benthic macroinvertebrate data were collected at 15 stream sites (reaches) in the preserve during 1999–2001 for a baseline assessment and a comparison of communities among stream reaches. The fish communities in the preserve were dominated by minnows (family Cyprinidae) and sunfishes (family Centrarchidae). Reaches with smaller channel sizes generally had higher fish species richness than the larger reaches in the Neches River and Pine Island Bayou units of the preserve. Fish communities in geographically adjacent reaches were most similar in overall community structure. The blue sucker, listed by the State as a threatened species, was collected in only one reach—a Neches River reach a few miles downstream from the Steinhagen Lake Dam. Riffle beetles (family Elmidae) and midges (family Chironomidae) dominated the aquatic insect communities at the 14 reaches sampled for aquatic insects in the preserve. The Ephemeroptera, Plecoptera and Trichoptera (EPT) Index, an index sensitive to water-quality degradation, was smallest at the Little Pine Island Bayou near Beaumont reach that is in a State 303(d)-listed stream segment on Little Pine Island Bayou. Trophic structure of the aquatic insect communities is consistent with the river continuum concept with shredder and scraper insect taxa more abundant in reaches with smaller stream channels and filter feeders more abundant in reaches with larger channels. Aquatic insect community metrics were not significantly correlated to any of the stream-habitat or land-use explanatory variables. The percentage of 1990s urban land use in the drainage areas upstream from 12 bioassessment reaches were negatively correlated to the reach structure index, which indicates less stable habitat for aquatic biota.

Forest habitat conservation in Africa using commercially important insects.

PubMed

Raina, Suresh Kumar; Kioko, Esther; Zethner, Ole; Wren, Susie

2011-01-01

African forests, which host some of the world's richest biodiversity, are rapidly diminishing. The loss of flora and fauna includes economically and socially important insects. Honey bees and silk moths, grouped under commercial insects, are the source for insect-based enterprises that provide income to forest-edge communities to manage the ecosystem. However, to date, research output does not adequately quantify the impact of such enterprises on buffering forest ecosystems and communities from climate change effects. Although diseases/pests of honey bees and silk moths in Africa have risen to epidemic levels, there is a dearth of practical research that can be utilized in developing effective control mechanisms that support the proliferation of these commercial insects as pollinators of agricultural and forest ecosystems. This review highlights the critical role of commercial insects within the environmental complexity of African forest ecosystems, in modern agroindustry, and with respect to its potential contribution to poverty alleviation and pollination services. It identifies significant research gaps that exist in understanding how insects can be utilized as ecosystem health indicators and nurtured as integral tools for important socioeconomic and industrial gains.

Nutritional composition and safety aspects of edible insects.

PubMed

Rumpold, Birgit A; Schlüter, Oliver K

2013-05-01

Insects, a traditional food in many parts of the world, are highly nutritious and especially rich in proteins and thus represent a potential food and protein source. A compilation of 236 nutrient compositions in addition to amino acid spectra and fatty acid compositions as well as mineral and vitamin contents of various edible insects as derived from literature is given and the risks and benefits of entomophagy are discussed. Although the data were subject to a large variation, it could be concluded that many edible insects provide satisfactorily with energy and protein, meet amino acid requirements for humans, are high in MUFA and/or PUFA, and rich in several micronutrients such as copper, iron, magnesium, manganese, phosphorous, selenium, and zinc as well as riboflavin, pantothenic acid, biotin, and in some cases folic acid. Liabilities of entomophagy include the possible content of allergenic and toxic substances as well as antinutrients and the presence of pathogens. More data are required for a thorough assessment of the nutritional potential of edible insects and proper processing and decontamination methods have to be developed to ensure food safety. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phenotypic responses to microbial volatiles render a mold fungus more susceptible to insect damage.

PubMed

Caballero Ortiz, Silvia; Trienens, Monika; Pfohl, Katharina; Karlovsky, Petr; Holighaus, Gerrit; Rohlfs, Marko

2018-04-01

In decomposer systems, fungi show diverse phenotypic responses to volatile organic compounds of microbial origin (volatiles). The mechanisms underlying such responses and their consequences for the performance and ecological success of fungi in a multitrophic community context have rarely been tested explicitly. We used a laboratory-based approach in which we investigated a tripartite yeast-mold-insect model decomposer system to understand the possible influence of yeast-borne volatiles on the ability of a chemically defended mold fungus to resist insect damage. The volatile-exposed mold phenotype (1) did not exhibit protein kinase A-dependent morphological differentiation, (2) was more susceptible to insect foraging activity, and (3) had reduced insecticidal properties. Additionally, the volatile-exposed phenotype was strongly impaired in secondary metabolite formation and unable to activate "chemical defense" genes upon insect damage. These results suggest that volatiles can be ecologically important factors that affect the chemical-based combative abilities of fungi against insect antagonists and, consequently, the structure and dynamics of decomposer communities.

Local structuring factors of invertebrate communities in ephemeral freshwater rock pools and the influence of more permanent water bodies in the region

USGS Publications Warehouse

Jocque, M.; Graham, T.; Brendonck, L.

2007-01-01

We used three isolated clusters of small ephemeral rock pools on a sandstone flat in Utah to test the importance of local structuring processes on aquatic invertebrate communities. In the three clusters we characterized all ephemeral rock pools (total: 27) for their morphometry, and monitored their water quality, hydrology and community assemblage during a full hydrocycle. In each cluster we also sampled a set of more permanent interconnected freshwater systems positioned in a wash, draining the water from each cluster of rock pools. This design allowed additional testing for the potential role of more permanent water bodies in the region as source populations for the active dispersers and the effect on the community structure in the rock pools. Species richness and community composition in the rock pools correlated with level of permanence and the ammonia concentration. The length of the rock pool inundation cycle shaped community structure, most probably by inhibiting colonization by some taxa (e.g. tadpoles and insect larvae) through developmental constraints. The gradient in ammonia concentrations probably reflects differences in primary production. The more permanent water bodies in each wash differed both environmentally and in community composition from the connected set of rock pools. A limited set of active dispersers was observed in the rock pools. Our findings indicate that aquatic invertebrate communities in the ephemeral rock pools are mainly structured through habitat permanence, possibly linked with biotic interactions and primary production. ?? 2007 Springer Science+Business Media B.V.

New Insights into the Microbiota of Moth Pests.

PubMed

Mereghetti, Valeria; Chouaia, Bessem; Montagna, Matteo

2017-11-18

In recent years, next generation sequencing (NGS) technologies have helped to improve our understanding of the bacterial communities associated with insects, shedding light on their wide taxonomic and functional diversity. To date, little is known about the microbiota of lepidopterans, which includes some of the most damaging agricultural and forest pests worldwide. Studying their microbiota could help us better understand their ecology and offer insights into developing new pest control strategies. In this paper, we review the literature pertaining to the microbiota of lepidopterans with a focus on pests, and highlight potential recurrent patterns regarding microbiota structure and composition.

New Insights into the Microbiota of Moth Pests

PubMed Central

Mereghetti, Valeria; Chouaia, Bessem

2017-01-01

In recent years, next generation sequencing (NGS) technologies have helped to improve our understanding of the bacterial communities associated with insects, shedding light on their wide taxonomic and functional diversity. To date, little is known about the microbiota of lepidopterans, which includes some of the most damaging agricultural and forest pests worldwide. Studying their microbiota could help us better understand their ecology and offer insights into developing new pest control strategies. In this paper, we review the literature pertaining to the microbiota of lepidopterans with a focus on pests, and highlight potential recurrent patterns regarding microbiota structure and composition. PMID:29156569

Needle terpenoid composition of Pinus halepensis (Mill.) Trees infested by the scale insect Marchalina hellenica (Genn.) in Greece

Treesearch

Athanassios Gallis; Carlos Arrabal; Aristotle C. Papageorgiou; Maria C. Garcia-Vallejo

2012-01-01

Needle terpenoid composition was determined by using GLC-MS in Pinus halepensis (Mill.) trees that were infested and not infested by the scale insect Marchalina hellenica. The study area was within the Forest National Park of the Cape Sounion, southern Attica region, Greece. A total of 43 compounds, 32 of which were identified...

VARIATION IN GROWTH, LIPID CLASS AND FATTY ACID COMPOSITION OF THE MUD CRAB, RHITHROPANOPEUS HARRISII (GOULD) DURING LARVAL DEVELOPMENT FOLLOWING EXPOSURE TO AN INSECT JUVENILE HORMONE ANALOG (FENOXYCARB(R))

EPA Science Inventory

This study examines the effects of fenoxycarb?, an insect juvenile hormone (JH) analog, on larval growth, and lipid class and fatty acid composition in first crabs of the mud crab Rhithropanopeus harrisii reared through total larval development in nominal water concentrations fr...

VARIATION IN GROWTH, LIPID CLASS AND FATTY ACID COMPOSITION OF THE MUD CRAB, RHITHROPANOPEUS HARRISII (GOULD) DURING LARVAL DEVELOPMENT FOLLOWING EXPOSURE TO AN INSECT JUVENILE HORMONE ANALOG (FENOXYCARB)

EPA Science Inventory

This study examines the effects of fenoxycarb?, an insect juvenile hormone analog, on larval growth, and lipid class and fatty acid composition in first crabs of the mud crab Rhithropanopeus harrisii reared through total larval development in nominal water concentrations from 1 ...

Large-scale patterns of insect and disease activity in the Conterminous United States and Alaska from the National Insect and Disease Detection Survey Database, 2007 and 2008

Treesearch

Kevin M. Potter

2012-01-01

Analyzing patterns of forest pest infestation is necessary for monitoring the health of forested ecosystems because of the impacts that insects and diseases can have on forest structure, composition, biodiversity, and species distributions (Castello and others 1995). In particular, introduced nonnative insects and diseases can extensively damage the diversity, ecology...

Microbial Brokers of Insect-Plant Interactions Revisited

PubMed Central

Douglas, Angela E

2013-01-01

Recent advances in sequencing methods have transformed the field of microbial ecology, making it possible to determine the composition and functional capabilities of uncultured microorganisms. These technologies have been instrumental in the recognition that resident microorganisms can have profound effects on the phenotype and fitness of their animal hosts by modulating the animal signaling networks that regulate growth, development, behavior, etc. Against this backdrop, this review assesses the impact of microorganisms on insect-plant interactions, in the context of the hypothesis that microorganisms are biochemical brokers of plant utilization by insects. There is now overwhelming evidence for a microbial role in insect utilization of certain plant diets with an extremely low or unbalanced nutrient content. Specifically, microorganisms enable insect utilization of plant sap by synthesizing essential amino acids. They also can broker insect utilization of plant products of extremely high lignocellulose content, by enzymatic breakdown of complex plant polysaccharides, nitrogen fixation, and sterol synthesis. However, the experimental evidence for microbial-mediated detoxification of plant allelochemicals is limited. The significance of microorganisms as brokers of plant utilization by insects is predicted to vary, possibly widely, as a result of potentially complex interactions between the composition of the microbiota and the diet and insect developmental age or genotype. For every insect species feeding on plant material, the role of resident microbiota as biochemical brokers of plant utilization is a testable hypothesis. PMID:23793897

Ecological Value of Native Plant Cultivars Versus Wild-Type Native Plants for Promoting Hemipteran Diversity in Suburban Areas.

PubMed

Poythress, J C; Affolter, James M

2018-04-14

Because of concerns over recent declines in overall biodiversity in suburban areas, homeowners are attempting to improve the ecological functioning of their landscapes by incorporating native plants. Native plants are important for supporting native herbivorous insects, but it is unknown whether the native plants that are commercially available, typically cultivated varieties (cultivars) of a single genotype, are equally effective as food sources as the local, wild-type plants. We compared the hemipteran communities feeding on cultivars and wild-propagated plants for four species of native perennials commonly used as ornamentals. Of 65 hemipteran species collected, 35 exhibited a preference for some plant species over others, indicating a high degree of host-plant specialization. Moreover, the insect community associated with cultivars was distinct from the insect community associated with wild-type plants for each plant species, with three to four insect species accounting for most of the observed difference. Total insect abundance and insect biomass differed between cultivars and wild-propagated plants, but the direction of the difference changed over time and was not consistent among plant species. Species richness and a diversity index (the Q statistic) did not differ between cultivars and wild-type plants. These data suggest that abundance and diversity of hemipteran insects does not depend on the source of the plant material per se, but rather on the particular characteristics of cultivars that distinguish them from the wild type.

Insect symbionts in food webs

PubMed Central

Henry, Lee M.

2016-01-01

Recent research has shown that the bacterial endosymbionts of insects are abundant and diverse, and that they have numerous different effects on their hosts' biology. Here we explore how insect endosymbionts might affect the structure and dynamics of insect communities. Using the obligate and facultative symbionts of aphids as an example, we find that there are multiple ways that symbiont presence might affect food web structure. Many symbionts are now known to help their hosts escape or resist natural enemy attack, and others can allow their hosts to withstand abiotic stress or affect host plant use. In addition to the direct effect of symbionts on aphid phenotypes there may be indirect effects mediated through trophic and non-trophic community interactions. We believe that by using data from barcoding studies to identify bacterial symbionts, this extra, microbial dimension to insect food webs can be better elucidated. This article is part of the themed issue ‘From DNA barcodes to biomes’. PMID:27481779

Influence of large woody debris on stream insect communities and benthic detritus

Treesearch

A. Dennis Lemly; Robert H. Hilderbrand

2000-01-01

We examined the extent to which benthic detritus loadings and the functional feeding group structure of stream insect communities respond to channel modifications produced by experimental addition of large woody debris (LWD, entire logs) to Stony Creek, VA. Benthic detritus loadings per sample did not change after LWD additions, but large increases in pool habitats...

[Distribution and species composition of hyporheic macroinvertebrates in a mountain stream].

PubMed

Zhang, Yue-wei; Yuan, Xing-zhong; Liu, Hong; Ren, Hai-qing; Deng, Wei; Wang, Xiao-feng

2015-09-01

Hyporheic macroinvertebrates are an important component of stream ecosystem. The composition and distribution of the hyporheic macroinvertebrates were investigated using artificial substrates in the upper reaches of Heishuitan River in August, December 2013 and April 2014. The results indicated that a total of 27 microinvertbrate species were identified in all three seasons. In summer, 22 species were identified, accounting for 81.8% of aquatic insects. 16 species were identified both in winter and spring, accounting for 75.0% and 62.5% of aquatic insects, respectively. The density of macroinvertebrate assemblage was significantly lower in summer than in winter and spring, and was the highest in spring. The biomass of macroinvertebrate assemblage was significantly higher in winter than in summer and spring, and was the lowest in summer. Species richness, Shannon index and Pielou index all had no significant difference among the three seasons. The density and richness of macroinvertebrates decreased with bed depth, and the maximum invertebrate density was found within the top 20 cm of the stream bed. Collector-filterer and collector-gatherer were the dominant functional feeding group in all three seasons. The community structure and temporal-spatial distribution of macroinvertebrates were determined by interactions and life history strategy of macroinvertebrates, and physical-chemical factors of hyporheic zone.

Cotton production in the presence of Helicoverpa armigera (Hb.) in Central Greece.

PubMed

Stavridis, D G; Gliatis, A; Deligeorgidis, P N; Giatropoulos, C; Giatropoulos, A; Deligeorgidis, N P; Ipsilandis, C G

2008-11-01

The present study was conducted in 10 different communities of prefecture of Larissa, one of the main cotton-productive areas of Greece. Monitoring of Helicoverpa armigera lasted four years from 2002 to 2005. The monitoring system included four locations within each community and three traps in each location. Traps were of the funnel type, a reusable injection-moulded kind of plastic trap. Pheromone was z-11-hexadecenyl aldehyde 0.36% w/w. Insecticide (Vapona) was used for all the four years, but for years 2003 and 2004 double traps were used additionally, without the presence of insecticide (only with pheromone). Traps containing a pheromone and an insecticide had significantly greater number of insects trapped than those containing no insecticide. Fluctuation of insect population was different from year to year. Correlations on data between years (insect populations and cotton production across all communities) revealed that, when cotton production was low, the number of adult male insects of H. armigera captured in pheromone traps was high (r = -0.69). There were no statistically significant correlations between cotton production and number of trapped insects when data from all communities (across the four years) were used. Local conditions within each area have been proved important and these results were completely different compared to data concerning specific years. Prediction models must be used for average estimations within great areas that include data from many locations.

Improved annotation of the insect vector of citrus greening disease: Biocuration by a diverse genomics community

USDA-ARS?s Scientific Manuscript database

The Asian citrus psyllid (Diaphorina citri Kuwayama) is the insect vector of the bacterium Candidatus Liberibacter asiaticus (CLas), the pathogen associated with citrus Huanglongbing (HLB, citrus greening). HLB threatens citrus production worldwide. Suppression or reduction of the insect vector usin...

An Insect Herbivore Microbiome with High Plant Biomass-Degrading Capacity

PubMed Central

Suen, Garret; Scott, Jarrod J.; Aylward, Frank O.; Adams, Sandra M.; Tringe, Susannah G.; Pinto-Tomás, Adrián A.; Foster, Clifton E.; Pauly, Markus; Weimer, Paul J.; Barry, Kerrie W.; Goodwin, Lynne A.; Bouffard, Pascal; Li, Lewyn; Osterberger, Jolene; Harkins, Timothy T.; Slater, Steven C.; Donohue, Timothy J.; Currie, Cameron R.

2010-01-01

Herbivores can gain indirect access to recalcitrant carbon present in plant cell walls through symbiotic associations with lignocellulolytic microbes. A paradigmatic example is the leaf-cutter ant (Tribe: Attini), which uses fresh leaves to cultivate a fungus for food in specialized gardens. Using a combination of sugar composition analyses, metagenomics, and whole-genome sequencing, we reveal that the fungus garden microbiome of leaf-cutter ants is composed of a diverse community of bacteria with high plant biomass-degrading capacity. Comparison of this microbiome's predicted carbohydrate-degrading enzyme profile with other metagenomes shows closest similarity to the bovine rumen, indicating evolutionary convergence of plant biomass degrading potential between two important herbivorous animals. Genomic and physiological characterization of two dominant bacteria in the fungus garden microbiome provides evidence of their capacity to degrade cellulose. Given the recent interest in cellulosic biofuels, understanding how large-scale and rapid plant biomass degradation occurs in a highly evolved insect herbivore is of particular relevance for bioenergy. PMID:20885794

Small bait traps as accurate predictors of dipteran early colonizers in forensic studies

PubMed Central

Farinha, Ana; Dourado, Catarina G.; Centeio, Neiva; Oliveira, Ana Rita; Dias, Deodália; Rebelo, Maria Teresa

2014-01-01

Abstract Insect carrion communities vary among habitats and over time. Concerning the dipteran early colonizers of carrion, the use of small bait traps should be accurate because the odors emitted from meat baits should contain many of the volatile organic compounds emitted from the freshly dead mammals. In addition, this kind of trap is easy to replicate and set in position in a given habitat. In the present study, small bait preferences of early Diptera carrion colonizers were examined in an urban biotope. Specifically, three baits were compared (pork muscle, pork liver, and fish flavored cat food) in respect to the number of specimens and species captured and the presence or absence of oviposition at high and low environmental temperatures. A total of 2371 specimens were trapped, primarily belonging to three insect orders, Diptera, Coleoptera, and Hymenoptera. Diptera was the predominant order, with blowflies (Calliphoridae) being the most representative family, followed by filth flies (Muscidae). The pork muscle bait was responsible for the highest number of captures and the highest diversity. The community of Diptera collected with the most efficient bait, pork muscle, was compared with the carrion communities reported in the literature from the Iberian Peninsula. Similar taxonomic species composition was found regarding Calliphoridae species. A specimen from all species morphologically identified were also identified at a molecular level using the cytochrome c oxidase I (COI) barcode region, and the sequences were submitted to online databases. PMID:25373224

Terpenoids in plant and arbuscular mycorrhiza-reinforced defence against herbivorous insects

PubMed Central

Sharma, Esha; Anand, Garima

2017-01-01

Background Plants, though sessile, employ various strategies to defend themselves against herbivorous insects and convey signals of an impending herbivore attack to other plant(s). Strategies include the production of volatiles that include terpenoids and the formation of symbiotic associations with fungi, such as arbuscular mycorrhiza (AM). This constitutes a two-pronged above-ground/below-ground attack–defence strategy against insect herbivores. Scope Terpenoids represent an important constituent of herbivore-induced plant volatiles that deter herbivores and/or attract their predators. Terpenoids serve as airborne signals that can induce defence responses in systemic undamaged parts of the plant and also prime defence responses in neighbouring plants. Colonization of roots by AM fungi is known to influence secondary metabolism in plants; this includes alteration of the concentration and composition of terpenoids, which can boost both direct and indirect plant defence against herbivorous insects. Enhanced nutrient uptake facilitated by AM, changes in plant morphology and physiology and increased transcription levels of certain genes involved in the terpenoid biosynthesis pathway result in alterations in plant terpenoid profiles. The common mycorrhizal networks of external hyphae have added a dimension to the two-pronged plant defence strategy. These act as conduits to transfer defence signals and terpenoids. Conclusion Improved understanding of the roles of terpenoids in plant and AM defences against herbivory and of interplant signalling in natural communities has significant implications for sustainable management of pests in agricultural ecosystems. PMID:28087662

An estimated 400-800 million tons of prey are annually killed by the global spider community.

PubMed

Nyffeler, Martin; Birkhofer, Klaus

2017-04-01

Spiders have been suspected to be one of the most important groups of natural enemies of insects worldwide. To document the impact of the global spider community as insect predators, we present estimates of the biomass of annually killed insect prey. Our estimates assessed with two different methods suggest that the annual prey kill of the global spider community is in the range of 400-800 million metric tons (fresh weight), with insects and collembolans composing >90% of the captured prey. This equals approximately 1‰ of the global terrestrial net primary production. Spiders associated with forests and grasslands account for >95% of the annual prey kill of the global spider community, whereas spiders in other habitats are rather insignificant contributors over a full year. The spider communities associated with annual crops contribute less than 2% to the global annual prey kill. This, however, can be partly explained by the fact that annual crop fields are "disturbed habitats" with a low buildup of spider biomass and that agrobiont spiders often only kill prey over short time periods in a year. Our estimates are supported by the published results of exclusion experiments, showing that the number of herbivorous/detritivorous insects and collembolans increased significantly after spider removal from experimental plots. The presented estimates of the global annual prey kill and the relative contribution of spider predation in different biomes improve the general understanding of spider ecology and provide a first assessment of the global impact of this very important predator group.

An estimated 400-800 million tons of prey are annually killed by the global spider community

NASA Astrophysics Data System (ADS)

Nyffeler, Martin; Birkhofer, Klaus

2017-04-01

Spiders have been suspected to be one of the most important groups of natural enemies of insects worldwide. To document the impact of the global spider community as insect predators, we present estimates of the biomass of annually killed insect prey. Our estimates assessed with two different methods suggest that the annual prey kill of the global spider community is in the range of 400-800 million metric tons (fresh weight), with insects and collembolans composing >90% of the captured prey. This equals approximately 1‰ of the global terrestrial net primary production. Spiders associated with forests and grasslands account for >95% of the annual prey kill of the global spider community, whereas spiders in other habitats are rather insignificant contributors over a full year. The spider communities associated with annual crops contribute less than 2% to the global annual prey kill. This, however, can be partly explained by the fact that annual crop fields are "disturbed habitats" with a low buildup of spider biomass and that agrobiont spiders often only kill prey over short time periods in a year. Our estimates are supported by the published results of exclusion experiments, showing that the number of herbivorous/detritivorous insects and collembolans increased significantly after spider removal from experimental plots. The presented estimates of the global annual prey kill and the relative contribution of spider predation in different biomes improve the general understanding of spider ecology and provide a first assessment of the global impact of this very important predator group.

Harnessing Host-Vector Microbiome for Sustainable Plant Disease Management of Phloem-Limited Bacteria.

PubMed

Trivedi, Pankaj; Trivedi, Chanda; Grinyer, Jasmine; Anderson, Ian C; Singh, Brajesh K

2016-01-01

Plant health and productivity is strongly influenced by their intimate interaction with deleterious and beneficial organisms, including microbes, and insects. Of the various plant diseases, insect-vectored diseases are of particular interest, including those caused by obligate parasites affecting plant phloem such as Candidatus ( Ca .) Phytoplasma species and several species of Ca. Liberibacter. Recent studies on plant-microbe and plant-insect interactions of these pathogens have demonstrated that plant-microbe-insect interactions have far reaching consequences for the functioning and evolution of the organisms involved. These interactions take place within complex pathosystems and are shaped by a myriad of biotic and abiotic factors. However, our current understanding of these processes and their implications for the establishment and spread of insect-borne diseases remains limited. This article highlights the molecular, ecological, and evolutionary aspects of interactions among insects, plants, and their associated microbial communities with a focus on insect vectored and phloem-limited pathogens belonging to Ca. Phytoplasma and Ca. Liberibacter species. We propose that innovative and interdisciplinary research aimed at linking scales from the cellular to the community level will be vital for increasing our understanding of the mechanisms underpinning plant-insect-microbe interactions. Examination of such interactions could lead us to applied solutions for sustainable disease and pest management.

Colour constancy in insects.

PubMed

Chittka, Lars; Faruq, Samia; Skorupski, Peter; Werner, Annette

2014-06-01

Colour constancy is the perceptual phenomenon that the colour of an object appears largely unchanged, even if the spectral composition of the illuminating light changes. Colour constancy has been found in all insect species so far tested. Especially the pollinating insects offer a remarkable opportunity to study the ecological significance of colour constancy since they spend much of their adult lives identifying and choosing between colour targets (flowers) under continuously changing ambient lighting conditions. In bees, whose colour vision is best studied among the insects, the compensation provided by colour constancy is only partial and its efficiency depends on the area of colour space. There is no evidence for complete 'discounting' of the illuminant in bees, and the spectral composition of the light can itself be used as adaptive information. In patchy illumination, bees adjust their spatial foraging to minimise transitions between variously illuminated zones. Modelling allows the quantification of the adaptive benefits of various colour constancy mechanisms in the economy of nature. We also discuss the neural mechanisms and cognitive operations that might underpin colour constancy in insects.

Fatty Acid Composition of Novel Host Jack Pine Do Not Prevent Host Acceptance and Colonization by the Invasive Mountain Pine Beetle and Its Symbiotic Fungus

PubMed Central

Ishangulyyeva, Guncha; Najar, Ahmed; Curtis, Jonathan M.

2016-01-01

Fatty acids are major components of plant lipids and can affect growth and development of insect herbivores. Despite a large literature examining the roles of fatty acids in conifers, relatively few studies have tested the effects of fatty acids on insect herbivores and their microbial symbionts. Particularly, whether fatty acids can affect the suitability of conifers for insect herbivores has never been studied before. Thus, we evaluated if composition of fatty acids impede or facilitate colonization of jack pine (Pinus banksiana) by the invasive mountain pine beetle (Dendroctonus ponderosae) and its symbiotic fungus (Grosmannia clavigera). This is the first study to examine the effects of tree fatty acids on any bark beetle species and its symbiotic fungus. In a novel bioassay, we found that plant tissues (hosts and non-host) amended with synthetic fatty acids at concentrations representative of jack pine were compatible with beetle larvae. Likewise, G. clavigera grew in media amended with lipid fractions or synthetic fatty acids at concentrations present in jack pine. In contrast, fatty acids and lipid composition of a non-host were not suitable for the beetle larvae or the fungus. Apparently, concentrations of individual, rather than total, fatty acids determined the suitability of jack pine. Furthermore, sampling of host and non-host tree species across Canada demonstrated that the composition of jack pine fatty acids was similar to the different populations of beetle’s historical hosts. These results demonstrate that fatty acids composition compatible with insect herbivores and their microbial symbionts can be important factor defining host suitability to invasive insects. PMID:27583820

Drought sensitivity predicts habitat size sensitivity in an aquatic ecosystem.

PubMed

Amundrud, Sarah L; Srivastava, Diane S

2015-07-01

Species and trophic richness often increase with habitat size. Although many ecological processes have been evoked to explain both patterns, the environmental stress associated with small habitats has rarely been considered. We propose that larger habitats may be species rich simply because their environmental conditions are within the fundamental niche of more species; larger habitats may also have more trophic levels if traits of predators render them vulnerable to environmental stress. We test this hypothesis using the aquatic insect larvae in water-filled bromeliads. In bromeliads, the probability of desiccation is greatest in small plants. For the 10 most common bromeliad insect taxa, we ask whether differences in drought tolerance and regional abundances between taxa predict community and trophic composition over a gradient of bromeliad size. First, we used bromeliad survey data to calculate the mean habitat size of occurrence of each taxon. Comparing the observed mean habitat size of occurrence to that expected from random species assembly based on differences in their regional abundances allowed us to obtain habitat size sensitivity indices (as Z scores) for the various insect taxa. Second, we obtained drought sensitivity indices by subjecting individual insects to drought and measuring the effects on relative growth rates in a mesocosm experiment. We found that drought sensitivity strongly, predicts habitat size sensitivity in bromeliad insects. However, an increase in trophic richness with habitat size could not be explained by an increased sensitivity of predators to drought, but rather by sampling effects, as predators were rare compared to lower trophic levels. This finding suggests that physiological tolerance to environmental stress can be relevant in explaining the universal increase in species with habitat size.

Global compositional variation among native and non-native regional insect assemblages emphasizes the importance of pathways

Treesearch

Andrew M. Liebhold; Takehiko Yamanaka; Alain Roques; Sylvie Augustin; Steven L. Chown; Eckehard G. Brockerhoff; Petr Pysek

2016-01-01

Insects are among the world's most ecologically and economically important invasive species. Here we assemble inventories of native and nonnative species from 20 world regions and contrast relative numbers among these species assemblages. Multivariate ordination indicates that the distribution of species among insect orders is completely different between native...

Sinergia sostenida: las polillas y el Dr. Wolcott

Treesearch

Frank H. Wadsworth

2007-01-01

The synergy between an insect colony and a curious entomologist is described. Together they determine the relative preference of insects to over 80 woody species. The relationship between wood resistance and insect attacks and wood density and chemical composition of wood is also determined. Finally, a series of chemicals is tested to increase wood resistance to attack...

Aquatic insect community of lake, Phulbari anua in Cachar, Assam.

PubMed

Gupta, Susmita; Narzary, Rupali

2013-05-01

An investigation on the water quality and aquatic insect community of an oxbow lake (Phulbari anua) of south Assam, North-East India was carried out during February to April, 2010. Aquatic insect community of the oxbow lake was represented by 9 species belonging to 9 families and 4 orders during the study period. Order Ephemeroptera and Hemiptera were found to be dominant. Record of 5 species and 5 families from the order Hemiptera showed that this is the largest order in terms of aquatic insect diversity of the lake. Computation of dominance status of different species of aquatic insects of the lake based on Engelmann's Scale revealed that Anisops lundbladiana and Cloeon sp. were eudominant in the system. The Shannon- Weiner's Diversity Index (H') and Shannon evenness values (J') were found to range from 0.3-0.69 and 0.53 -0.97, respectively indicating perturbation of the system. Again in terms of physico-chemical properties of water the lake is in a satisfactory condition where all the parameters are well within the range of IS 10500. The DO values were found to range from 6.8 to 14.8 mgl(-1). Free CO2 fluctuated from 1 to 4.98 mgl(-1) and nitrate in water ranged from 0.4 to 2.1 mgl(-1). Margalef's water quality index values of most of the samplings also indicated clean water condition of the lake. Correlation coefficient analyses of the environmental variables, aquatic insect diversity and density of the lake revealed that aquatic insect diversity of the lake is mainly governed by dissolved oxygen, nitrate, and free carbon dioxide.

Distributional patterns in an insect community inhabiting a sandy beach of Uruguay

NASA Astrophysics Data System (ADS)

Mourglia, Virginia; González-Vainer, Patricia; Defeo, Omar

2015-12-01

Most studies of sandy beach macrofauna have been restricted to semiterrestrial species and do not include insects when providing species richness and abundance estimates. Particularly, spatio-temporal patterns of community structure of the entomofauna inhabiting these ecosystems have been scarcely documented. This study assessed spatio-temporal distributional patterns of the night active entomofauna on a beach-dune system of Uruguay, including variations in species richness, abundance and diversity, and their relationship with environmental factors. A deconstructive taxonomic analysis was also performed, considering richness and abundance patterns separately for the most abundant insect Orders (Hymenoptera and Coleoptera) to better understand the factors which drive their patterns. We found clear temporal and across-shore patterns in the insect community inhabiting a land-ocean interface, which matched spatiotemporal variations in the environment. Abundance and species richness were highest in spring and summer, concurrently with high temperatures and low values of sediment moisture and compaction. Multivariate ordinations showed two well-defined species groups, which separated summer, autumn and spring samples from winter ones. Generalized Linear Models allowed us to describe a clear segregation in space of the most important orders of the insect community, with specific preferences for the terrestrial (Hymenoptera) and beach (Coleoptera) fringes. Hymenoptera preferred the dune zone, characterized by high elevation and low sand moisture and compaction levels, whereas Coleoptera preferred gentle slopes and fine and humid sands of the beach. Our results suggest that beach and dune ecosystems operate as two separate components in regard to their physical and biological features. The high values of species richness and abundance of insects reveal that this group has a more significant ecological role than that originally considered so far in sandy beach ecology.

Molecular Ecological Basis of Grasshopper (Oedaleus asiaticus) Phenotypic Plasticity under Environmental Selection

PubMed Central

Qin, Xinghu; Hao, Kun; Ma, Jingchuan; Huang, Xunbing; Tu, Xiongbing; Ali, Md. Panna; Pittendrigh, Barry R.; Cao, Guangchun; Wang, Guangjun; Nong, Xiangqun; Whitman, Douglas W.; Zhang, Zehua

2017-01-01

While ecological adaptation in insects can be reflected by plasticity of phenotype, determining the causes and molecular mechanisms for phenotypic plasticity (PP) remains a crucial and still difficult question in ecology, especially where control of insect pests is involved. Oedaleus asiaticus is one of the most dominant pests in the Inner Mongolia steppe and represents an excellent system to study phenotypic plasticity. To better understand ecological factors affecting grasshopper phenotypic plasticity and its molecular control, we conducted a full transcriptional screening of O. asiaticus grasshoppers reared in four different grassland patches in Inner Mongolia. Grasshoppers showed different degrees of PP associated with unique gene expressions and different habitat plant community compositions. Grasshopper performance variables were susceptible to habitat environment conditions and closely associated with plant architectures. Intriguingly, eco-transcriptome analysis revealed five potential candidate genes playing important roles in grasshopper performance, with gene expression closely relating to PP and plant community factors. By linking the grasshopper performances to gene profiles and ecological factors using canonical regression, we first demonstrated the eco-transcriptomic architecture (ETA) of grasshopper phenotypic traits (ETAGPTs). ETAGPTs revealed plant food type, plant density, coverage, and height were the main ecological factors influencing PP, while insect cuticle protein (ICP), negative elongation factor A (NELFA), and lactase-phlorizin hydrolase (LCT) were the key genes associated with PP. Our study gives a clear picture of gene-environment interaction in the formation and maintenance of PP and enriches our understanding of the transcriptional events underlying molecular control of rapid phenotypic plasticity associated with environmental variability. The findings of this study may also provide new targets for pest control and highlight the significance of ecological management practice on grassland conservation. PMID:29066978

Effect of Pet Insects on the Psychological Health of Community-Dwelling Elderly People: A Single-Blinded, Randomized, Controlled Trial.

PubMed

Ko, Hae-Jin; Youn, Chang-Ho; Kim, Seong-Hyun; Kim, So-Yun

2016-01-01

There is evidence that animal-assisted therapy has positive effects on mental health, especially in elderly people. Caring for insects is easy, relatively inexpensive, and does not require much space. The aim of this 8-week randomized, controlled, single-blinded study was to investigate the effect of pet insects on the psychological health of community-dwelling elderly people. Elderly subjects (≥65 years old) attending a community center in Daegu, Korea, were enrolled in the study between April and May 2014 and randomized at a 1:1 ratio to receive insect therapy and health advice or only health advice. The insect group received 5 crickets in a cage with sufficient fodder and a detailed instruction manual. At baseline and at 8 weeks, all subjects underwent psychometric tests via a direct interview [Beck Anxiety Inventory, Geriatric Depression Scale (GDS-15), Mini-Mental State Examination (MMSE), 36-Item Short Form Health Survey, Insomnia Severity Index, Fatigue Severity Scale, and Brief Encounter Psychosocial Instrument] and laboratory analyses of inflammatory and oxidative stress markers (erythrocyte sedimentation rate, high-sensitivity C-reactive protein, biological antioxidant potential, and derivatives of reactive oxygen metabolites). The insect-caring (n = 46) and control (n = 48) groups did not differ in baseline characteristics. The insect-caring group had significantly lower GDS-15 scores at week 8 (3.20 vs. 4.90, p = 0.004) and, after adjustment for baseline values, a significantly greater change in GDS-15 scores relative to baseline (-1.12 vs. 0.20, p = 0.011). They also had a significantly greater change in MMSE scores relative to baseline (1.13 vs. 0.31, p = 0.045). The two groups did not differ in terms of other psychometric and laboratory tests. No serious risks or adverse events were reported. Caring for insects, which is cost-effective and safe, was associated with a small to medium positive effect on depression and cognitive function in community-dwelling elderly people. © 2015 S. Karger AG, Basel.

Variation in gut microbial communities and its association with pathogen infection in wild bumble bees (Bombus)

PubMed Central

Cariveau, Daniel P; Elijah Powell, J; Koch, Hauke; Winfree, Rachael; Moran, Nancy A

2014-01-01

Bacterial gut symbiont communities are critical for the health of many insect species. However, little is known about how microbial communities vary among host species or how they respond to anthropogenic disturbances. Bacterial communities that differ in richness or composition may vary in their ability to provide nutrients or defenses. We used deep sequencing to investigate gut microbiota of three species in the genus Bombus (bumble bees). Bombus are among the most economically and ecologically important non-managed pollinators. Some species have experienced dramatic declines, probably due to pathogens and land-use change. We examined variation within and across bee species and between semi-natural and conventional agricultural habitats. We categorized as ‘core bacteria' any operational taxonomic units (OTUs) with closest hits to sequences previously found exclusively or primarily in the guts of honey bees and bumble bees (genera Apis and Bombus). Microbial community composition differed among bee species. Richness, defined as number of bacterial OTUs, was highest for B. bimaculatus and B. impatiens. For B. bimaculatus, this was due to high richness of non-core bacteria. We found little effect of habitat on microbial communities. Richness of non-core bacteria was negatively associated with bacterial abundance in individual bees, possibly due to deeper sampling of non-core bacteria in bees with low populations of core bacteria. Infection by the gut parasite Crithidia was negatively associated with abundance of the core bacterium Gilliamella and positively associated with richness of non-core bacteria. Our results indicate that Bombus species have distinctive gut communities, and community-level variation is associated with pathogen infection. PMID:24763369

Before the 'Big Chill': Patterns of plant-insect associations from the Neogene of Iceland

NASA Astrophysics Data System (ADS)

Wappler, Torsten; Grímsson, Friðgeir

2016-07-01

Iceland is the only known terrestrial place in the subarctic North Atlantic providing a fairly continuous sedimentary and plant fossil record over the past 15 million years. While the basic palaeobotanical framework of this pattern has been well established during the last decade, less attention has been paid to the abundant insect traces on fossil leaves/leaflets. Here, we assess the diversity and frequency of insect herbivory on 4349 fossil angiosperm leaves/leaflets from six plant-bearing sedimentary formations exposed at 18 localities. By combining analyses of environmental factors, species interactions, ecology, biogeography, and the geological history, our results demonstrate how patterns of herbivory have changed over time in relation to temperature fluctuations that profoundly influenced levels of insect-mediated damage diversity and frequency. In addition, higher structural complexity, particularly the establishment of species-rich herb layer communities seems to have positively influenced the structure of insect communities in early late Miocene palaeoforests of Iceland.

Radiocesium Transfer in Forest Insect Communities after the Fukushima Dai-ichi Nuclear Power Plant Accident.

PubMed

Ishii, Yumiko; Hayashi, Seiji; Takamura, Noriko

2017-01-01

To understand radiocesium transfer in the forest insect food web, we investigated the activity concentrations of radiocesium in forest insects in the Fukushima and Ibaraki Prefectures approximately 1.5-2.5 years after the Fukushima Dai-ichi Nuclear Power Plant. We analyzed 34 species of insects sampled from 4 orders and 4 feeding functional groups (herbivore, carnivore, omnivore, and detritivore) from three sites in each prefecture. 137Cs activity concentrations were lowest in herbivorous species and were especially high in detritivorous and omnivorous species that feed on forest litter and fungi. Radiocesium activity concentrations in any given species reflected the degree of contamination of that species' primary food sources since radiocesium activity concentrations were found to be the lowest in leaves and grass and the highest in litter, bark, and fungi. This study confirmed that litter and other highly contaminated forest components such as fungi, decaying wood, bryophytes, and lichens serve as sources of 137Cs transfer into the forest insect community.

Radiocesium Transfer in Forest Insect Communities after the Fukushima Dai-ichi Nuclear Power Plant Accident

PubMed Central

Hayashi, Seiji; Takamura, Noriko

2017-01-01

To understand radiocesium transfer in the forest insect food web, we investigated the activity concentrations of radiocesium in forest insects in the Fukushima and Ibaraki Prefectures approximately 1.5–2.5 years after the Fukushima Dai-ichi Nuclear Power Plant. We analyzed 34 species of insects sampled from 4 orders and 4 feeding functional groups (herbivore, carnivore, omnivore, and detritivore) from three sites in each prefecture. 137Cs activity concentrations were lowest in herbivorous species and were especially high in detritivorous and omnivorous species that feed on forest litter and fungi. Radiocesium activity concentrations in any given species reflected the degree of contamination of that species’ primary food sources since radiocesium activity concentrations were found to be the lowest in leaves and grass and the highest in litter, bark, and fungi. This study confirmed that litter and other highly contaminated forest components such as fungi, decaying wood, bryophytes, and lichens serve as sources of 137Cs transfer into the forest insect community. PMID:28125745

Changes in aquatic insect emergence in response to whole-lake experimental manipulations of introduced trout

Treesearch

Karen L. Pope; Jonah Piovia-Scott; Sharon P. Lawler

2009-01-01

1. Insects emerging from mountain lakes provide an important food source for many terrestrial predators. The amount of insect subsidy that emerges from lakes is influenced by predator composition, but predator effects could be ameliorated by greater habitat complexity. We conducted a replicated whole-lake experiment to test the effects of introduced fish...

Interspecific interactions in phytophagous insects revisited: a quantitative assessment of competition theory.

PubMed

Kaplan, Ian; Denno, Robert F

2007-10-01

The importance of interspecific competition is a highly controversial and unresolved issue for community ecology in general, and for phytophagous insects in particular. Recent advancements, however, in our understanding of indirect (plant- and enemy-mediated) interactions challenge the historical paradigms of competition. Thus, in the context of this rapidly developing field, we re-evaluate the evidence for interspecific competition in phytophagous insects using a meta-analysis of published studies. Our analysis is specifically designed to test the assumptions underlying traditional competition theory, namely that competitive interactions are symmetrical, necessitate spatial and temporal co-occurrence, and increase in intensity as the density, phylogenetic similarity, and niche overlap of competing species increase. Despite finding frequent evidence for competition, we found very little evidence that plant-feeding insects conform to theoretical predictions for interspecific competition. Interactions were highly asymmetrical, similar in magnitude within vs. between feeding guilds (chewers vs. sap-feeders), and were unaffected by the quantity of resources removed (% defoliation). There was mixed support for the effects of phylogeny, spatial/temporal separation, and the relative strength of intra- vs. interspecific competition. Clearly, a new paradigm that accounts for indirect interactions and facilitation is required to describe how interspecific competition contributes to the organization of phytophagous insect communities, and perhaps to other plant and animal communities as well.

Microbial secondary metabolites and their impacts on insect symbioses.

PubMed

Klassen, Jonathan L

2014-10-01

All insects host communities of microbes that interact both with the insect and each other. Secondary metabolites are understood to mediate many of these interactions, although examples having robust genetic, chemical and/or ecological evidence are relatively rare. Here, I review secondary metabolites mediating community interactions in the beewolf, entomopathogenic nematode and fungus-growing ant symbioses, using the logic of Koch's postulates to emphasize well-validated symbiotic functions mediated by these metabolites. I especially highlight how these interaction networks are structured by both ecological and evolutionary processes, and how selection acting on secondary metabolite production can be multidimensional. Copyright © 2014 Elsevier Inc. All rights reserved.

Microbial ecology-based methods to characterize the bacterial communities of non-model insects.

PubMed

Prosdocimi, Erica M; Mapelli, Francesca; Gonella, Elena; Borin, Sara; Crotti, Elena

2015-12-01

Among the animals of the Kingdom Animalia, insects are unparalleled for their widespread diffusion, diversity and number of occupied ecological niches. In recent years they have raised researcher interest not only because of their importance as human and agricultural pests, disease vectors and as useful breeding species (e.g. honeybee and silkworm), but also because of their suitability as animal models. It is now fully recognized that microorganisms form symbiotic relationships with insects, influencing their survival, fitness, development, mating habits and the immune system and other aspects of the biology and ecology of the insect host. Thus, any research aimed at deepening the knowledge of any given insect species (perhaps species of applied interest or species emerging as novel pests or vectors) must consider the characterization of the associated microbiome. The present review critically examines the microbiology and molecular ecology techniques that can be applied to the taxonomical and functional analysis of the microbiome of non-model insects. Our goal is to provide an overview of current approaches and methods addressing the ecology and functions of microorganisms and microbiomes associated with insects. Our focus is on operational details, aiming to provide a concise guide to currently available advanced techniques, in an effort to extend insect microbiome research beyond simple descriptions of microbial communities. Copyright © 2015 Elsevier B.V. All rights reserved.

Intraspecific chemical diversity among neighbouring plants correlates positively with plant size and herbivore load but negatively with herbivore damage.

PubMed

Bustos-Segura, Carlos; Poelman, Erik H; Reichelt, Michael; Gershenzon, Jonathan; Gols, Rieta

2017-01-01

Intraspecific plant diversity can modify the properties of associated arthropod communities and plant fitness. However, it is not well understood which plant traits determine these ecological effects. We explored the effect of intraspecific chemical diversity among neighbouring plants on the associated invertebrate community and plant traits. In a common garden experiment, intraspecific diversity among neighbouring plants was manipulated using three plant populations of wild cabbage that differ in foliar glucosinolates. Plants were larger, harboured more herbivores, but were less damaged when plant diversity was increased. Glucosinolate concentration differentially correlated with generalist and specialist herbivore abundance. Glucosinolate composition correlated with plant damage, while in polycultures, variation in glucosinolate concentrations among neighbouring plants correlated positively with herbivore diversity and negatively with plant damage levels. The results suggest that intraspecific variation in secondary chemistry among neighbouring plants is important in determining the structure of the associated insect community and positively affects plant performance. © 2016 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Harnessing Host-Vector Microbiome for Sustainable Plant Disease Management of Phloem-Limited Bacteria

PubMed Central

Trivedi, Pankaj; Trivedi, Chanda; Grinyer, Jasmine; Anderson, Ian C.; Singh, Brajesh K.

2016-01-01

Plant health and productivity is strongly influenced by their intimate interaction with deleterious and beneficial organisms, including microbes, and insects. Of the various plant diseases, insect-vectored diseases are of particular interest, including those caused by obligate parasites affecting plant phloem such as Candidatus (Ca.) Phytoplasma species and several species of Ca. Liberibacter. Recent studies on plant–microbe and plant–insect interactions of these pathogens have demonstrated that plant–microbe–insect interactions have far reaching consequences for the functioning and evolution of the organisms involved. These interactions take place within complex pathosystems and are shaped by a myriad of biotic and abiotic factors. However, our current understanding of these processes and their implications for the establishment and spread of insect-borne diseases remains limited. This article highlights the molecular, ecological, and evolutionary aspects of interactions among insects, plants, and their associated microbial communities with a focus on insect vectored and phloem-limited pathogens belonging to Ca. Phytoplasma and Ca. Liberibacter species. We propose that innovative and interdisciplinary research aimed at linking scales from the cellular to the community level will be vital for increasing our understanding of the mechanisms underpinning plant–insect–microbe interactions. Examination of such interactions could lead us to applied solutions for sustainable disease and pest management. PMID:27746788

Competition with wind-pollinated plant species alters floral traits of insect-pollinated plant species

PubMed Central

Flacher, Floriane; Raynaud, Xavier; Hansart, Amandine; Motard, Eric; Dajoz, Isabelle

2015-01-01

Plant traits related to attractiveness to pollinators (e.g. flowers and nectar) can be sensitive to abiotic or biotic conditions. Soil nutrient availability, as well as interactions among insect-pollinated plants species, can induce changes in flower and nectar production. However, further investigations are needed to determine the impact of interactions between insect-pollinated species and abiotically pollinated species on such floral traits, especially floral rewards. We carried out a pot experiment in which three insect-pollinated plant species were grown in binary mixtures with four wind-pollinated plant species, differing in their competitive ability. Along the flowering period, we measured floral traits of the insect-pollinated species involved in attractiveness to pollinators (i.e. floral display size, flower size, daily and total 1) flower production, 2) nectar volume, 3) amount of sucrose allocated to nectar). Final plant biomass was measured to quantify competitive interactions. For two out of three insect-pollinated species, we found that the presence of a wind-pollinated species can negatively impact floral traits involved in attractiveness to pollinators. This effect was stronger with wind-pollinated species that induced stronger competitive interactions. These results stress the importance of studying the whole plant community (and not just the insect-pollinated plant community) when working on plant-pollinator interactions. PMID:26335409

Conversion from long-term cultivated wheat field to Jerusalem artichoke plantation changed soil fungal communities

NASA Astrophysics Data System (ADS)

Zhou, Xingang; Zhang, Jianhui; Gao, Danmei; Gao, Huan; Guo, Meiyu; Li, Li; Zhao, Mengliang; Wu, Fengzhi

2017-01-01

Understanding soil microbial communities in agroecosystems has the potential to contribute to the improvement of agricultural productivity and sustainability. Effects of conversion from long-term wheat plantation to Jerusalem artichoke (JA) plantation on soil fungal communities were determined by amplicon sequencing of total fungal ITS regions. Quantitative PCR and PCR-denaturing gradient gel electrophoresis were also used to analyze total fungal and Trichoderma spp. ITS regions and Fusarium spp. Ef1α genes. Results showed that soil organic carbon was higher in the first cropping of JA and Olsen P was lower in the third cropping of JA. Plantation conversion changed soil total fungal and Fusarium but not Trichoderma spp. community structures and compositions. The third cropping of JA had the lowest total fungal community diversity and Fusarium spp. community abundance, but had the highest total fungal and Trichoderma spp. community abundances. The relative abundances of potential fungal pathogens of wheat were higher in the wheat field. Fungal taxa with plant growth promoting, plant pathogen or insect antagonistic potentials were enriched in the first and second cropping of JA. Overall, short-term conversion from wheat to JA plantation changed soil fungal communities, which is related to changes in soil organic carbon and Olsen P contents.

Conversion from long-term cultivated wheat field to Jerusalem artichoke plantation changed soil fungal communities

PubMed Central

Zhou, Xingang; Zhang, Jianhui; Gao, Danmei; Gao, Huan; Guo, Meiyu; Li, Li; Zhao, Mengliang; Wu, Fengzhi

2017-01-01

Understanding soil microbial communities in agroecosystems has the potential to contribute to the improvement of agricultural productivity and sustainability. Effects of conversion from long-term wheat plantation to Jerusalem artichoke (JA) plantation on soil fungal communities were determined by amplicon sequencing of total fungal ITS regions. Quantitative PCR and PCR-denaturing gradient gel electrophoresis were also used to analyze total fungal and Trichoderma spp. ITS regions and Fusarium spp. Ef1α genes. Results showed that soil organic carbon was higher in the first cropping of JA and Olsen P was lower in the third cropping of JA. Plantation conversion changed soil total fungal and Fusarium but not Trichoderma spp. community structures and compositions. The third cropping of JA had the lowest total fungal community diversity and Fusarium spp. community abundance, but had the highest total fungal and Trichoderma spp. community abundances. The relative abundances of potential fungal pathogens of wheat were higher in the wheat field. Fungal taxa with plant growth promoting, plant pathogen or insect antagonistic potentials were enriched in the first and second cropping of JA. Overall, short-term conversion from wheat to JA plantation changed soil fungal communities, which is related to changes in soil organic carbon and Olsen P contents. PMID:28134269

Microbial community structure in the gut of the New Zealand insect Auckland tree weta (Hemideina thoracica).

PubMed

Waite, David W; Dsouza, Melissa; Biswas, Kristi; Ward, Darren F; Deines, Peter; Taylor, Michael W

2015-05-01

The endemic New Zealand weta is an enigmatic insect. Although the insect is well known by its distinctive name, considerable size, and morphology, many basic aspects of weta biology remain unknown. Here, we employed cultivation-independent enumeration techniques and rRNA gene sequencing to investigate the gut microbiota of the Auckland tree weta (Hemideina thoracica). Fluorescence in situ hybridisation performed on different sections of the gut revealed a bacterial community of fluctuating density, while rRNA gene-targeted amplicon pyrosequencing revealed the presence of a microbial community containing high bacterial diversity, but an apparent absence of archaea. Bacteria were further studied using full-length 16S rRNA gene sequences, with statistical testing of bacterial community membership against publicly available termite- and cockroach-derived sequences, revealing that the weta gut microbiota is similar to that of cockroaches. These data represent the first analysis of the weta microbiota and provide initial insights into the potential function of these microorganisms.

Characterization of the gut bacterial community in Manduca sexta and effect of antibiotics on bacterial diversity and nematode reproduction.

PubMed

van der Hoeven, Ransome; Betrabet, Geeta; Forst, Steven

2008-09-01

The tobacco hornworm, Manduca sexta, is a model lepidopteran insect used to study the pathogenic and mutualistic phases of entomopathogenic nematodes (EPNs) and their bacterial symbionts. While intestinal microbial communities could potentially compete with the EPN and its bacterial partner for nutrient resources of the insect, the microbial gut community had not been characterized previously. Here, we show that the midgut of M. sexta raised on an artificial diet contained mostly Gram-positive cocci and coryneforms including Staphylococcus, Pediococcus, Micrococcus and Corynebacterium. Major perturbation in the gut community was observed on addition of antibiotics to the diet. Paenibacillus and several Proteobacteria such as Methylobacterium, Sphingomonas and Acinetobacter were primary genera identified under these conditions. Furthermore, the reproduction of the nematode Steinernema carpocapsae was less efficient, and the level of nematode colonization by its symbiont Xenorhabdus nematophila reduced, in insects reared on a diet containing antibiotics. The effect of antibiotics and perturbation of gut microbiota on nematode reproduction is discussed.

Ecological risk assessment for residual coal fly ash at Watts Bar Reservoir, Tennessee: Limited alteration of riverine-reservoir benthic invertebrate community following dredging of ash-contaminated sediment.

PubMed

Buys, David J; Stojak, Amber R; Stiteler, William; Baker, Tyler F

2015-01-01

Benthic invertebrate communities were assessed after the December 2008 release of approximately 4.1 million m(3) coal fly ash from a disposal dredge cell at the Tennessee Valley Authority (TVA) Kingston Fossil Plant on Watts Bar Reservoir in Roane County, Tennessee, USA. Released ash filled the adjacent embayments and the main channel of the Emory River, migrating into reaches of the Emory, Clinch, and Tennessee Rivers. Dredging was completed in summer 2010, and the benthic community sampling was conducted in December 2010. This study is part of a series that supported an Ecological Risk Assessment for the Kingston site. Benthic invertebrate communities were sampled at transects spread across approximately 20 miles of river that includes both riverine and reservoirlike conditions. Community composition was assessed on a grab sample and transect basis across multiple cross-channel transects to gain an understanding of the response of the benthic community to a fly ash release of this magnitude. This assessment used invertebrate community metrics, similarity analysis, geospatial statistics, and correlations with sediment chemistry and habitat. The community composition was reflective of a reservoir system, with dominant taxa being insect larva, bivalves, and aquatic worms. Most community metric results were similar for ash-impacted areas and upstream reference areas. Variation in the benthic community was correlated more with habitat than with sediment chemistry or residual ash. Other studies have reported that a benthic community can take several years to a decade to recover from ash or ash-related constituents. Although released ash undoubtedly had some initial impacts on the benthic community in this study, the severity of these effects appears to be limited to the initial smothering of the organisms followed by a rapid response and the initial start of recovery postdredging. © 2014 SETAC.

Large-scale patterns of insect and disease activity in the conterminous United States and Alaska from the National Insect and Disease Detection Survey Database, 2010

Treesearch

Kevin M. Potter; Jeanine L. Paschke

2013-01-01

Analyzing patterns of forest pest infestations, diseases occurrences, forest declines and related biotic stress factors is necessary to monitor the health of forested ecosystems and their potential impacts on forest structure, composition, biodiversity, and species distributions (Castello and others 1995). Introduced nonnative insects and diseases, in particular, can...

Large-scale patterns of insect and disease activity in the conterminous United States and Alaska from the national insect and disease detection survey, 2009

Treesearch

Kevin M. Potter

2013-01-01

Analyzing patterns of forest pest infestation, disease occurrences, forest declines, and related biotic stress factors is necessary to monitor the health of forested ecosystems and their potential impacts on forest structure, composition, biodiversity, and species distributions (Castello and others 1995). Introduced nonnative insects and diseases, in particular, can...

Development of an aggressive bark beetle on novel hosts: Implications for outbreaks in an invaded range

Treesearch

Derek W. Rosenberger; Robert C. Venette; Brian H. Aukema; Jörg Müller

2018-01-01

Some subcortical insects have devastating effects on native tree communities in new ranges, despite benign interactions with their historical hosts. Examples of how insects, aggressive in their native habitat might respond in novel host environs are less common. One aggressive tree-killing insect undergoing a dramatic range shift is the mountain pine beetle (...

Historical and projected interactions between climate change and insect voltinism in a multivoltine species

Treesearch

Patrick C. Tobin; Sudha Nagarkatti; Greg Loeb; Michael C. Saunders

2008-01-01

Climate change can cause major changes to the dynamics of individual species and to those communities in which they interact. One effect of increasing temperatures is on insect voltinism, with the logical assumption that increases in surface temperatures would permit multivoltine species to increase the number of generations per year. Though insect development is...

Estimating Pre-treatment Variation in the Oak Leaf-chewing Insect Fauna of the Missouri Ozark Forest Ecosystem Project (MOFEP)

Treesearch

Robert J. Marquis; Josiane Le Corff

1997-01-01

We describe spatial and temporal variation in the insect herbivore communities associated with the MOFEP, prior to application of contrasting cutting regimes. No pre-treatment differences were found in total insect density on either black (Quercus velutina) or white oak (Q. alba) during 1993-1995. There was great seasonal...

Bacterial community diversity and variation in spray water sources and the tomato fruit surface.

PubMed

Telias, Adriana; White, James R; Pahl, Donna M; Ottesen, Andrea R; Walsh, Christopher S

2011-04-21

Tomato (Solanum lycopersicum) consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water) when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production. The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant. Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an important step forward towards the development of science-based metrics for Good Agricultural Practices.

In Vitro Iron Availability from Insects and Sirloin Beef.

PubMed

Latunde-Dada, Gladys O; Yang, Wenge; Vera Aviles, Mayra

2016-11-09

Interest in the consumption of insects (entomophagy) as an alternative environmentally sustainable source of protein in the diet of humans has recently witnessed a surge. Knowledge of the nutrient composition and, in particular, the bioavailability of minerals from insects is currently sparse. This study evaluated the availability of Fe, Ca, Cu, Mg, Mn, and Zn from four commonly eaten insects and compared these to sirloin beef. Soluble iron from the samples was measured by inductively coupled plasma optical emission spectrometry (ICP-OES). Iron bioavailability was determined using an in vitro simulated peptic-pancreatic digestion, followed by measurement of ferritin (a surrogate marker for iron absorption) in Caco-2 cells. Cricket and sirloin beef had comparably higher levels of Fe, Ca, and Mn than grasshopper, meal, and buffalo worms. However, iron solubility was significantly higher from the insect samples than from beef. The complementation of whole-wheat flour with insect or beef protein resulted in overall decreases in mineral content and iron solubility in the composite mixtures. Collectively, the data show that grasshopper, cricket, and mealworms contain significantly higher chemically available Ca, Cu, Mg, Mn, and Zn than sirloin. However, buffalo worms and sirloin exhibited higher iron bioavailability comparable to that of FeSO 4 . Commonly consumed insect species could be excellent sources of bioavailable iron and could provide the platform for an alternative strategy for increased mineral intake in the diets of humans.

Higher-level phylogeny of paraneopteran insects inferred from mitochondrial genome sequences

PubMed Central

Li, Hu; Shao, Renfu; Song, Nan; Song, Fan; Jiang, Pei; Li, Zhihong; Cai, Wanzhi

2015-01-01

Mitochondrial (mt) genome data have been proven to be informative for animal phylogenetic studies but may also suffer from systematic errors, due to the effects of accelerated substitution rate and compositional heterogeneity. We analyzed the mt genomes of 25 insect species from the four paraneopteran orders, aiming to better understand how accelerated substitution rate and compositional heterogeneity affect the inferences of the higher-level phylogeny of this diverse group of hemimetabolous insects. We found substantial heterogeneity in base composition and contrasting rates in nucleotide substitution among these paraneopteran insects, which complicate the inference of higher-level phylogeny. The phylogenies inferred with concatenated sequences of mt genes using maximum likelihood and Bayesian methods and homogeneous models failed to recover Psocodea and Hemiptera as monophyletic groups but grouped, instead, the taxa that had accelerated substitution rates together, including Sternorrhyncha (a suborder of Hemiptera), Thysanoptera, Phthiraptera and Liposcelididae (a family of Psocoptera). Bayesian inference with nucleotide sequences and heterogeneous models (CAT and CAT + GTR), however, recovered Psocodea, Thysanoptera and Hemiptera each as a monophyletic group. Within Psocodea, Liposcelididae is more closely related to Phthiraptera than to other species of Psocoptera. Furthermore, Thysanoptera was recovered as the sister group to Hemiptera. PMID:25704094

Using Next-Generation Sequencing to Contrast the Diet and Explore Pest-Reduction Services of Sympatric Bird Species in Macadamia Orchards in Australia.

PubMed

Crisol-Martínez, Eduardo; Moreno-Moyano, Laura T; Wormington, Kevin R; Brown, Philip H; Stanley, Dragana

2016-01-01

Worldwide, avian communities inhabiting agro-ecosystems are threatened as a consequence of agricultural intensification. Unravelling their ecological role is essential to focus conservation efforts. Dietary analysis can elucidate bird-insect interactions and expose avian pest-reduction services, thus supporting avian conservation. In this study, we used next-generation sequencing to analyse the dietary arthropod contents of 11 sympatric bird species foraging in macadamia orchards in eastern Australia. Across all species and based on arthropod DNA sequence similarities ≥98% with records in the Barcode of Life Database, 257 operational taxonomy units were assigned to 8 orders, 40 families, 90 genera and 89 species. These taxa included 15 insect pests, 5 of which were macadamia pests. Among the latter group, Nezara viridula (Pentatomidae; green vegetable bug), considered a major pest, was present in 23% of all faecal samples collected. Results also showed that resource partitioning in this system is low, as most bird species shared large proportion of their diets by feeding primarily on lepidopteran, dipteran and arachnids. Dietary composition differed between some species, most likely because of differences in foraging behaviour. Overall, this study reached a level of taxonomic resolution never achieved before in the studied species, thus contributing to a significant improvement in the avian ecological knowledge. Our results showed that bird communities prey upon economically important pests in macadamia orchards. This study set a precedent by exploring avian pest-reduction services using next-generation sequencing, which could contribute to the conservation of avian communities and their natural habitats in agricultural systems.

Using Next-Generation Sequencing to Contrast the Diet and Explore Pest-Reduction Services of Sympatric Bird Species in Macadamia Orchards in Australia

PubMed Central

Crisol-Martínez, Eduardo; Moreno-Moyano, Laura T.; Wormington, Kevin R.; Brown, Philip H.; Stanley, Dragana

2016-01-01

Worldwide, avian communities inhabiting agro-ecosystems are threatened as a consequence of agricultural intensification. Unravelling their ecological role is essential to focus conservation efforts. Dietary analysis can elucidate bird-insect interactions and expose avian pest-reduction services, thus supporting avian conservation. In this study, we used next-generation sequencing to analyse the dietary arthropod contents of 11 sympatric bird species foraging in macadamia orchards in eastern Australia. Across all species and based on arthropod DNA sequence similarities ≥98% with records in the Barcode of Life Database, 257 operational taxonomy units were assigned to 8 orders, 40 families, 90 genera and 89 species. These taxa included 15 insect pests, 5 of which were macadamia pests. Among the latter group, Nezara viridula (Pentatomidae; green vegetable bug), considered a major pest, was present in 23% of all faecal samples collected. Results also showed that resource partitioning in this system is low, as most bird species shared large proportion of their diets by feeding primarily on lepidopteran, dipteran and arachnids. Dietary composition differed between some species, most likely because of differences in foraging behaviour. Overall, this study reached a level of taxonomic resolution never achieved before in the studied species, thus contributing to a significant improvement in the avian ecological knowledge. Our results showed that bird communities prey upon economically important pests in macadamia orchards. This study set a precedent by exploring avian pest-reduction services using next-generation sequencing, which could contribute to the conservation of avian communities and their natural habitats in agricultural systems. PMID:26930484

Exploring the Influence of Differentiated Nutrition Information on Consumers' Mental Models Regarding Foods from Edible Insects: A Means-End Chain Analysis.

PubMed

Pambo, Kennedy O; Okello, Julius J; Mbeche, Robert M; Kinyuru, John N

2017-01-01

This study used a field experiment and means-end chain analysis to examine the effects of positive and perceived negative nutrition information on the households' motivations to consume insect-based foods. It used a random sample of households drawn from rural communities in Kenya. The study found that provision of nutrition information on benefits of edible insects and perceived negative aspects of insect-based foods influences participants' perceptions of insect-based foods and hence acceptance. We also found that tasting real products influenced the nature of mental constructs. The results provide marketers of edible insects with potential marketing messages for promotion.

Spider diversity in coffee agroecosystems: the influence of agricultural intensification and aggressive ants.

PubMed

Marín, Linda; Perfecto, Ivette

2013-04-01

Spiders are a very diverse group of invertebrate predators found in agroecosystems and natural systems. However, spider distribution, abundance, and eventually their ecological function in ecosystems can be influenced by abiotic and biotic factors such as agricultural intensification and dominant ants. Here we explore the influence of both agricultural intensification and the dominant arboreal ant Azteca instabilis on the spider community in coffee agroecosystems in southern Mexico. To measure the influence of the arboreal ant Azteca instabilis (F. Smith) on the spider community inhabiting the coffee layer of coffee agroecosystems, spiders were collected from coffee plants that were and were not patrolled by the ant in sites differing in agricultural intensification. For 2008, generalized linear mixed models showed that spider diversity was affected positively by agricultural intensification but not by the ant. However, results suggested that some spider species were associated with A. instabilis. Therefore, in 2009 we concentrated our research on the effect of A. instabilis on spider diversity and composition. For 2009, generalized linear mixed models show that spider richness and abundance per plant were significantly higher in the presence of A. instabilis. In addition, analyses of visual counts of insects and sticky traps data show that more resources were present in plants patrolled by the ant. The positive effect of A. instabilis on spiders seems to be caused by at least two mechanisms: high abundance of insects and protection against predators.

Effects of an increase in population of sika deer on beetle communities in deciduous forests.

PubMed

Iida, Taichi; Soga, Masashi; Koike, Shinsuke

2016-01-01

The overabundance of large herbivores is now recognized as a serious ecological problem. However, the resulting ecological consequences remain poorly understood. The ecological effects of an increase in sika deer, Cervus nippon Temminck (Cervidae), on three insect groups of beetles was investigated: ground beetles (Carabidae), carrion beetles (Silphidae), and dung beetles (Scarabaeidae and Geotrupidae) on Nakanoshima Island, Hokkaido, northern Japan. We collected beetles on Nakanoshima Island (experimental site) and lakeshore areas (control site) and compared the species richness, abundance, diversity index, and community composition of beetles between the sites. Results showed that although both species diversity and abundance of carabid beetles were significantly higher at the lakeshore site, those of dung and carrion beetles were higher at the island site. It was additionally observed that abundance of larger carabid beetles was higher at the lakeshore site, whereas that of small-sized carabid beetles did not differ between the lakeshore and island sites. For dung beetles, abundance of smaller species was higher at the island site, whereas that of large species did not differ between the lakeshore and island sites. Abundance of two body sizes (small and large) of carrion beetles were both higher at the island site. Overall, the findings of this study demonstrated that an increase in deer population altered the insect assemblages at an island scale, suggesting further changes in ecosystem functions and services in this region.

Leaf quality and insect herbivory in model tropical plant communities after long-term exposure to elevated atmospheric CO2.

PubMed

Arnone, J A; Zaller, J G; Körner, Ch; Ziegler, C; Zandt, H

1995-09-01

Results from laboratory feeding experiments have shown that elevated atmospheric carbon dioxide can affect interactions between plants and insect herbivores, primarily through changes in leaf nutritional quality occurring at elevated CO 2 . Very few data are available on insect herbivory in plant communities where insects can choose among species and positions in the canopy in which to feed. Our objectives were to determine the extent to which CO 2 -induced changes in plant communities and leaf nutritional quality may affect herbivory at the level of the entire canopy. We introduced equivalent populations of fourth instar Spodoptera eridania, a lepidopteran generalist, to complex model ecosystems containing seven species of moist tropical plants maintained under low mineral nutrient supply. Larvae were allowed to feed freely for 14 days, by which time they had reached the seventh instar. Prior to larval introductions, plant communities had been continuously exposed to either 340 μl CO 2 l -1 or to 610 μl CO 2 l -1 for 1.5 years. No major shifts in leaf nutritional quality [concentrations of N, total non-structural carbohydrates (TNC), sugar, and starch; ratios of: C/N, TNC/N, sugar/N, starch/N; leaf toughness] were observed between CO 2 treatments for any of the species. Furthermore, no correlations were observed between these measures of leaf quality and leaf biomass consumption. Total leaf area and biomass of all plant communities were similar when caterpillars were introduced. However, leaf biomass of some species was slightly greater-and for other species slightly less (e.g. Cecropia peltata)-in communities exposed to elevated CO 2 . Larvae showed the strongest preference for C. peltata leaves, the plant species that was least abundant in all communites, and fed relatively little on plants species which were more abundant. Thus, our results indicate that leaf tissue quality, as described by these parameters, is not necessarily affected by elevated CO 2 under relatively low nutrient conditions. Hence, the potential importance of CO 2 -induced shifts in leaf nutritional quality, as determinants of herbivory, may be overestimated for many plant communities growing on nutrient-poor sites if estimates are based on traditional laboratory feeding studies. Finally, slight shifts in the abundance of leaf tissue of various species occurring under elevated CO 2 will probably not significantly affect herbivory by generalist insects. However, generalist insect herbivores appear to become more dependent on less-preferred plant species in cases where elevated CO 2 results in reduced availability of leaves of a favoured plant species, and this greater dependency may eventually affect insect populations adversely.

The protective role of endogenous bacterial communities in chironomid egg masses and larvae

PubMed Central

Senderovich, Yigal; Halpern, Malka

2013-01-01

Insects of the family Chironomidae, also known as chironomids, are distributed worldwide in a variety of water habitats. These insects display a wide range of tolerance toward metals and organic pollutions. Bacterial species known for their ability to degrade toxicants were identified from chironomid egg masses, leading to the hypothesis that bacteria may contribute to the survival of chironomids in polluted environments. To gain a better understanding of the bacterial communities that inhabit chironomids, the endogenous bacteria of egg masses and larvae were studied by 454-pyrosequencing. The microbial community of the egg masses was distinct from that of the larval stage, most likely due to the presence of one dominant bacterial Firmicutes taxon, which consisted of 28% of the total sequence reads from the larvae. This taxon may be an insect symbiont. The bacterial communities of both the egg masses and the larvae were found to include operational taxonomic units, which were closely related to species known as toxicant degraders. Furthermore, various bacterial species with the ability to detoxify metals were isolated from egg masses and larvae. Koch-like postulates were applied to demonstrate that chironomid endogenous bacterial species protect the insect from toxic heavy metals. We conclude that chironomids, which are considered pollution tolerant, are inhabited by stable endogenous bacterial communities that have a role in protecting their hosts from toxicants. This phenomenon, in which bacteria enable the continued existence of their host in hostile environments, may not be restricted only to chironomids. PMID:23804150

Linking Insects with Crustacea: Physiology of the Pancrustacea: An Introduction to the Symposium.

PubMed

Tamone, Sherry L; Harrison, Jon F

2015-11-01

Insects and crustaceans represent critical, dominant animal groups (by biomass and species number) in terrestrial and aquatic systems, respectively. Insects (hexapods) and crustaceans are historically grouped under separate taxonomic classes within the Phylum Arthropoda, and the research communities studying hexapods and crustaceans are quite distinct. More recently, the hexapods have been shown to be evolutionarily derived from basal crustaceans, and the clade Pancrustacea recognizes this relationship. This recent evolutionary perspective, and the fact that the Society for Integrative and Comparative Biology has strong communities in both invertebrate biology and insect physiology, provides the motivation for this symposium. Speakers in this symposium were selected because of their expertise in a particular field of insect or crustacean physiology, and paired in such a way as to provide a comparative view of the state of the current research in their respective fields. Presenters discussed what aspects of the physiological system are clearly conserved across insects and crustaceans and how cross-talk between researchers utilizing insects and crustaceans can fertilize understanding of such conserved systems. Speakers were also asked to identify strategies that would enable improved understanding of the evolution of physiological systems of the terrestrial insects from the aquatic crustaceans. The following collection of articles describes multiple recent advances in our understanding of Pancrustacean physiology. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

The molecular basis of bacterial-insect symbiosis.

PubMed

Douglas, Angela E

2014-11-25

Insects provide experimentally tractable and cost-effective model systems to investigate the molecular basis of animal-bacterial interactions. Recent research is revealing the central role of the insect innate immune system, especially anti-microbial peptides and reactive oxygen species, in regulating the abundance and composition of the microbiota in various insects, including Drosophila and the mosquitoes Aedes and Anopheles. Interactions between the immune system and microbiota are, however, bidirectional with evidence that members of the resident microbiota can promote immune function, conferring resistance to pathogens and parasites by both activation of immune effectors and production of toxins. Antagonistic and mutualistic interactions among bacteria have also been implicated as determinants of the microbiota composition, including exclusion of pathogens, but the molecular mechanisms are largely unknown. Some bacteria are crucial for insect nutrition, through provisioning of specific nutrients (e.g., B vitamins, essential amino acids) and modulation of the insect nutritional sensing and signaling pathways (e.g., insulin signaling) that regulate nutrient allocation, especially to lipid and other energy reserves. A key challenge for future research is to identify the molecular interaction between specific bacterial effectors and animal receptors, as well as to determine how these interactions translate into microbiota-dependent signaling, metabolism, and immune function in the host. Copyright © 2014. Published by Elsevier Ltd.

Profiling Hyporheic Microbial Community Nitrogen Cycle and Carbohydrate Active Enzyme Gene Abundances across Seasons

NASA Astrophysics Data System (ADS)

Nelson, W. C.; Graham, E.; Stegen, J.

2016-12-01

The hyporheic zone (HZ) is the permanently inundated sediment layer between a surface channel and adjacent groundwater-saturated sediments. It has been hypothesized to play a major role in macronutrient (C, N, P) cycling in rivers. The correlation between community taxonomic composition dynamics and functional gene representation is poorly understood for hyporheic communities. To explore how microbial communities respond to temporal changes in environmental conditions, metagenomes were derived from communities captured in sterile sandpacks deployed within the HZ of the Columbia River. HMM databases were used to enumerate protein families present. Functional classification of reads allowed a general assessment of community function over time, while targeted assembly of specific genes enabled investigation of the diversity of organisms encoding these functions. Preliminary analysis of nitrogen cycle pathways shows most gene families examined to have quite steady representation across seasons, with most observed changes being less than an order of magnitude. Analysis of ammonia oxidation genes showed bacterial ammonia oxidizers (AOB) to be stably present across the year, while the archaeal amoA gene increased in late summer, peaking sharply in November, mirroring results from 16S rRNA amplicon analysis which showed an increase in Thaumarcheal OTUs during that same period. Most glycosyl hydrolase GH families had low representation. Highly abundant classes of GH included the GH94 (beta-glucosidase), GH95 (1-2-alpha-L-fucosidase) and GH103 (lytic transglycosylase) families, suggesting activity on plant, fungus and insect polysaccharides and peptidoglycans. Further work is investigating the taxonomy of the sequences identified, to determine how changes in the community composition contribute to the stable gene family profiles observed. These results are intended to work towards a greater understanding of the role of species diversity and functional redundancy in the dynamics of community composition in response to changes in environmental conditions and stochastic processes. In addition, it will serve as a foundation enabling modeling of generalized microbial function in the hyporheic zone, improving our ability to predict fluxes of carbon and nitrogen through riverine systems.

Land-use legacies and present fire regimes interact to mediate herbivory by altering the neighboring plant community

DOE PAGES

Hahn, Philip G.; Orrock, John L.

2014-10-03

Past and present human activities, such as historic agriculture and fire suppression, are widespread and can create depauperate plant communities. Although many studies show that herbivory on focal plants depends on the density of herbivores or the composition of the surrounding plant community, it is unclear whether anthropogenic changes to plant communities alter herbivory. We tested the hypothesis that human activities that alter the plant community lead to subsequent changes in herbivory. At 20 sites distributed across 80 300 hectares, we conducted a field experiment that manipulated insect herbivore access (full exclosures and pseudo-exclosures) to four focal plant species inmore » longleaf pine woodlands with diff erent land-use histories (post-agricultural sites or non-agricultural sites) and degrees of fi re frequency (frequent and infrequent). Plant cover, particularly herbaceous cover, was lower in post-agricultural and fi re suppressed woodlands. Density of the dominant insect herbivore at our site (grasshoppers) was positively related to plant cover. Herbivore access reduced biomass of the palatable forb Solidago odora in frequently burned post-agricultural sites and in infrequently burned non-agricultural woodlands and increased mortality of another forb (Pityopsis graminifolia ), but did not aff ect two other less palatable species ( Schizachyrium scoparium and Tephrosia virginiana ). Herbivory on S. odora exhibited a hump-shaped response to plant cover, with low herbivory at low and high levels of plant cover. Herbivore density had a weak negative effect on herbivory. These findings suggest that changes in plant cover related to past and present human activities can modify damage rates on focal S. odora plants by altering grasshopper foraging behavior rather than by altering local grasshopper density. The resulting changes in herbivory may have the potential to limit natural recovery or restoration eff orts by reducing the establishment or performance of palatable plant species.« less

Land-use legacies and present fire regimes interact to mediate herbivory by altering the neighboring plant community

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hahn, Philip G.; Orrock, John L.

Past and present human activities, such as historic agriculture and fire suppression, are widespread and can create depauperate plant communities. Although many studies show that herbivory on focal plants depends on the density of herbivores or the composition of the surrounding plant community, it is unclear whether anthropogenic changes to plant communities alter herbivory. We tested the hypothesis that human activities that alter the plant community lead to subsequent changes in herbivory. At 20 sites distributed across 80 300 hectares, we conducted a field experiment that manipulated insect herbivore access (full exclosures and pseudo-exclosures) to four focal plant species inmore » longleaf pine woodlands with diff erent land-use histories (post-agricultural sites or non-agricultural sites) and degrees of fi re frequency (frequent and infrequent). Plant cover, particularly herbaceous cover, was lower in post-agricultural and fi re suppressed woodlands. Density of the dominant insect herbivore at our site (grasshoppers) was positively related to plant cover. Herbivore access reduced biomass of the palatable forb Solidago odora in frequently burned post-agricultural sites and in infrequently burned non-agricultural woodlands and increased mortality of another forb (Pityopsis graminifolia ), but did not aff ect two other less palatable species ( Schizachyrium scoparium and Tephrosia virginiana ). Herbivory on S. odora exhibited a hump-shaped response to plant cover, with low herbivory at low and high levels of plant cover. Herbivore density had a weak negative effect on herbivory. These findings suggest that changes in plant cover related to past and present human activities can modify damage rates on focal S. odora plants by altering grasshopper foraging behavior rather than by altering local grasshopper density. The resulting changes in herbivory may have the potential to limit natural recovery or restoration eff orts by reducing the establishment or performance of palatable plant species.« less

Identification of metabolically active bacteria in the gut of the generalist Spodoptera littoralis via DNA stable isotope probing using 13C-glucose.

PubMed

Shao, Yongqi; Arias-Cordero, Erika M; Boland, Wilhelm

2013-11-13

Guts of most insects are inhabited by complex communities of symbiotic nonpathogenic bacteria. Within such microbial communities it is possible to identify commensal or mutualistic bacteria species. The latter ones, have been observed to serve multiple functions to the insect, i.e. helping in insect reproduction(1), boosting the immune response(2), pheromone production(3), as well as nutrition, including the synthesis of essential amino acids(4,) among others.     Due to the importance of these associations, many efforts have been made to characterize the communities down to the individual members. However, most of these efforts were either based on cultivation methods or relied on the generation of 16S rRNA gene fragments which were sequenced for final identification. Unfortunately, these approaches only identified the bacterial species present in the gut and provided no information on the metabolic activity of the microorganisms. To characterize the metabolically active bacterial species in the gut of an insect, we used stable isotope probing (SIP) in vivo employing (13)C-glucose as a universal substrate. This is a promising culture-free technique that allows the linkage of microbial phylogenies to their particular metabolic activity. This is possible by tracking stable, isotope labeled atoms from substrates into microbial biomarkers, such as DNA and RNA(5). The incorporation of (13)C isotopes into DNA increases the density of the labeled DNA compared to the unlabeled ((12)C) one. In the end, the (13)C-labeled DNA or RNA is separated by density-gradient ultracentrifugation from the (12)C-unlabeled similar one(6). Subsequent molecular analysis of the separated nucleic acid isotopomers provides the connection between metabolic activity and identity of the species. Here, we present the protocol used to characterize the metabolically active bacteria in the gut of a generalist insect (our model system), Spodoptera littoralis (Lepidoptera, Noctuidae). The phylogenetic analysis of the DNA was done using pyrosequencing, which allowed high resolution and precision in the identification of insect gut bacterial community. As main substrate, (13)C-labeled glucose was used in the experiments. The substrate was fed to the insects using an artificial diet.

Influence of Habitat and Land Use on the Assemblages of Ephemeroptera, Plecoptera, and Trichoptera in Neotropical Streams

PubMed Central

do Amaral, Pedro Henrique Monteiro; da Silveira, Lidimara Souza; Rosa, Beatriz Figueiraujo Jabour Vescovi; de Oliveira, Vívian Campos; Alves, Roberto da Gama

2015-01-01

Insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) are often used to assess the conditions of aquatic environments, but few studies have examined the differences in these communities between riffles and pools. Our objective was to test whether riffles shelter greater richness and abundance of EPT, as well as to assess the sensitivity of these insects for detecting impacts from different land uses in streams in southeastern Brazil. Samples were collected in the dry season of 2012 with a Surber sampler in riffles and pools of nine streams (forest, pasture, and urban areas). Principal component analysis distinguished the streams according to different land uses as a function of percentage of plant cover and water oxygenation level and showed partial distinction between riffles and pools as a function of current speed and percentage of ultrafine sand. Detrended correspondence analysis indicated the distinction in EPT composition between riffles and pools, except in urban streams. The results of this study confirm the expected differences in the EPT fauna structure between riffles and pools, especially in forest and pasture environments. The individual metrics of riffle and pool assemblages showed significantly different responses to land use. Therefore, we suggest individual sampling of riffles and pools, since the metrics of these assemblages’ insects can differ between these habitats and influence the results of assessments in low-order streams. PMID:25989807

Recovery of aquatic insect-mediated methylmercury flux from ponds following drying disturbance.

PubMed

Chumchal, Matthew M; Drenner, Ray W; Greenhill, Frank M; Kennedy, James H; Courville, Ashlyn E; Gober, Charlie A A; Lossau, Luke O

2017-08-01

Small ponds exist across a permanence gradient, and pond permanence is hypothesized to be a primary determinant of insect community structure and insect-mediated methylmercury (MeHg) flux from ponds to the surrounding terrestrial landscape. The present study describes the first experiment examining the recovery of insect-mediated MeHg flux following a drying disturbance that converted permanent ponds with insectivorous fish to semipermanent ponds without fish. Floating emergence traps were used to collect emergent insects for 10 wk in the spring and summer from 5 ponds with fish (permanent) and 5 ponds that were drained to remove fish, dried, and refilled with water (semipermanent). During the 73-d period after semipermanent ponds were refilled, total MeHg flux from semipermanent ponds was not significantly different than total MeHg flux from permanent ponds, indicating that insect-mediated MeHg flux had rapidly recovered in semipermanent ponds following the drying disturbance. Methylmercury fluxes from dragonflies (Odonata: Anisoptera) and phantom midges (Diptera: Chaoboridae) were significantly greater from newly refilled semipermanent ponds than permanent ponds, but the MeHg fluxes from the other 8 emergent insect taxa did not differ between treatments. The present study demonstrates the impact of drying disturbance and the effect of community structure on the cross-system transport of contaminants from aquatic to terrestrial ecosystems. Environ Toxicol Chem 2017;36:1986-1990. © 2017 SETAC. © 2017 SETAC.

Aquatic insect assemblages associated with subalpine stream segment types in relict glaciated headwaters

USGS Publications Warehouse

Kubo, Joshua S.; Torgersen, Christian E.; Bolton, Susan M.; Weekes, Anne A.; Gara, Robert I.

2013-01-01

1. Aquatic habitats and biotic assemblages in subalpine headwaters are sensitive to climate and human impacts. Understanding biotic responses to such perturbations and the contribution of high-elevation headwaters to riverine biodiversity requires the assessment of assemblage composition among habitat types. We compared aquatic insect assemblages among headwater stream segment types in relict glaciated subalpine basins in Mt. Rainier National Park, Washington, USA. 2. Aquatic insects were collected during summer and autumn in three headwater basins. In each basin, three different stream segment types were sampled: colluvial groundwater sources, alluvial lake inlets, and cascade-bedrock lake outlets. Ward's hierarchical cluster analysis revealed high β diversity in aquatic insect assemblages, and non-metric multidimensional scaling indicated that spatial and temporal patterns in assemblage composition differed among headwater stream segment types. Aquatic insect assemblages showed more fidelity to stream segment types than to individual basins, and the principal environmental variables associated with assemblage structure were temperature and substrate. 3. Indicator species analyses identified specific aquatic insects associated with each stream segment type. Several rare and potentially endemic aquatic insect taxa were present, including the recently described species, Lednia borealis (Baumann and Kondratieff). 4. Our results indicate that aquatic insect assemblages in relict glaciated subalpine headwaters were strongly differentiated among stream segment types. These results illustrate the contribution of headwaters to riverine biodiversity and emphasise the importance of these habitats for monitoring biotic responses to climate change. Monitoring biotic assemblages in high-elevation headwaters is needed to prevent the potential loss of unique and sensitive biota.

Little effects of reduced-impact logging on insect communities in eastern Amazonia.

PubMed

Nogueira, Denis Silva; Calvão, Lenize Batista; de Assis Montag, Luciano Fogaça; Juen, Leandro; De Marco, Paulo

2016-07-01

Selective logging has become a major source of threats to tropical forest, bringing challenges for both ecologists and managers to develop low-impact forestry. Reduced-impact logging (RIL) is a prominent activity accounting for such forestry practices to prevent strong forest disturbances. Our aims were to evaluate the effects of RIL on insect communities of forested streams from Eastern Amazon and to test the hypothesis of negative effects of RIL on species richness, abundance, and functional feeding groups of aquatic insect assemblages. Neither of the evaluated metrics of the studied assemblages were negatively affected by RIL. Environmental metrics, such as substrate heterogeneity, woody canopy cover, and hill slope height, varied more among RIL streams than in reference streams, indicating a gradient according to logging impacts, and are suitable candidates to monitor RIL impacts in Amazonian streams. In addition, the PHI index also varied among REF and RIL, according to age class and year of logging, which could reflect trends to recover the forest structure after logging in a time frame of only 10 years. We conclude that RIL impacts have not had detrimental impacts on insect communities, but have changed little of the environmental conditions, especially of the riparian vegetation around streams.

Aquatic macroinvertebrates associated with Eichhornia azurea (Swartz) Kunth and relationships with abiotic factors in marginal lentic ecosystems (São Paulo, Brazil).

PubMed

Silva, C V; Henry, R

2013-02-01

Marginal lakes are characterised by their having high biological diversity due to the presence of aquatic macrophytes in their coastal zones, providing habitats for refuge and food for animal community members. Among the fauna components associated with macrophytes, aquatic macroinvertebrates are important because they are an energy source for predators and fish. In six lakes and two different seasons (March and August 2009), the ecological attributes of aquatic macroinvertebrate community associated with Eichhornia azurea were compared and the controlling environmental factors were identified. Since the attributes of macroinvertebrate community are strictly associated with abiotic variables of each distinct habitat, our hypothesis was that each site associated with the same floating aquatic macrophyte (E. azurea) should have a typical composition and density of organisms. We identified 50 taxa of macroinvertebrates, with greater taxa richness for aquatic insects (37 taxa) divided into eight orders; the order Diptera being the most abundant in the two study periods. On the other hand, higher values of total taxa richness were recorded in August. Dissolved oxygen and pH presented the greatest number of significant positive correlations with the different taxa. The animals most frequently collected in the six lakes in March and August 2009 were Hirudinea, Oligochaeta, Hydrachnidae, Conchostraca, Ostracoda, Noteridae, Ceratopogonidae, Chironomidae, Culicidae, Caenidae, Pleidae, Aeshnidae, Libellulidae, Coenagrionidae and Nematoda. Only densities of Trichoptera, Ostracoda and Conchostraca presented the highest significant differences between lakes in both study periods and considering the composition of macroinvertebrates no significant differences were registered for macroinvertebrate composition.

Detectability of landscape effects on recolonization increases with regional population density

PubMed Central

Liman, Anna-Sara; Dalin, Peter; Björkman, Christer

2015-01-01

Variation in population size over time can influence our ability to identify landscape-moderated differences in community assembly. To date, however, most studies at the landscape scale only cover snapshots in time, thereby overlooking the temporal dynamics of populations and communities. In this paper, we present data that illustrate how temporal variation in population density at a regional scale can influence landscape-moderated variation in recolonization and population buildup in disturbed habitat patches. Four common insect species, two omnivores and two herbivores, were monitored over 8 years in 10 willow short-rotation coppice bio-energy stands with a four-year disturbance regime (coppice cycle). The population densities in these regularly disturbed stands were compared to densities in 17 undisturbed natural Salix cinerea (grey willow) stands in the same region. A time series approach was used, utilizing the natural variation between years to statistically model recolonization as a function of landscape composition under two different levels of regional density. Landscape composition, i.e. relative amount of forest vs. open agricultural habitats, largely determined the density of re-colonizing populations following willow coppicing in three of the four species. However, the impact of landscape composition was not detectable in years with low regional density. Our results illustrate that landscape-moderated recolonization can change over time and that considering the temporal dynamics of populations may be crucial when designing and evaluating studies at landscape level. PMID:26257881

Detectability of landscape effects on recolonization increases with regional population density.

PubMed

Liman, Anna-Sara; Dalin, Peter; Björkman, Christer

2015-07-01

Variation in population size over time can influence our ability to identify landscape-moderated differences in community assembly. To date, however, most studies at the landscape scale only cover snapshots in time, thereby overlooking the temporal dynamics of populations and communities. In this paper, we present data that illustrate how temporal variation in population density at a regional scale can influence landscape-moderated variation in recolonization and population buildup in disturbed habitat patches. Four common insect species, two omnivores and two herbivores, were monitored over 8 years in 10 willow short-rotation coppice bio-energy stands with a four-year disturbance regime (coppice cycle). The population densities in these regularly disturbed stands were compared to densities in 17 undisturbed natural Salix cinerea (grey willow) stands in the same region. A time series approach was used, utilizing the natural variation between years to statistically model recolonization as a function of landscape composition under two different levels of regional density. Landscape composition, i.e. relative amount of forest vs. open agricultural habitats, largely determined the density of re-colonizing populations following willow coppicing in three of the four species. However, the impact of landscape composition was not detectable in years with low regional density. Our results illustrate that landscape-moderated recolonization can change over time and that considering the temporal dynamics of populations may be crucial when designing and evaluating studies at landscape level.

A Distinctive and Host-Restricted Gut Microbiota in Populations of a Cactophilic Drosophila Species.

PubMed

Martinson, Vincent G; Carpinteyro-Ponce, Javier; Moran, Nancy A; Markow, Therese A

2017-12-01

Almost all animals possess gut microbial communities, but the nature of these communities varies immensely. For example, in social bees and mammals, the composition is relatively constant within species and is dominated by specialist bacteria that do not live elsewhere; in laboratory studies and field surveys of Drosophila melanogaster , however, gut communities consist of bacteria that are ingested with food and that vary widely among individuals and localities. We addressed whether an ecological specialist in its natural habitat has a microbiota dominated by gut specialists or by environmental bacteria. Drosophila nigrospiracula is a species that is endemic to the Sonoran Desert and is restricted to decaying tissues of two giant columnar cacti, Pachycereus pringlei (cardón cactus) and Carnegiea gigantea (saguaro cactus). We found that the D. nigrospiracula microbiota differs strikingly from that of the cactus tissue on which the flies feed. The most abundant bacteria in the flies are rare or completely absent in the cactus tissue and are consistently abundant in flies from different cacti and localities. Several of these fly-associated bacterial groups, such as the bacterial order Orbales and the genera Serpens and Dysgonomonas , have been identified in prior surveys of insects from the orders Hymenoptera, Coleoptera, Lepidoptera, and Diptera, including several Drosophila species. Although the functions of these bacterial groups are mostly unexplored, Orbales species studied in bees are known to break down plant polysaccharides and use the resulting sugars. Thus, these bacterial groups appear to be specialized to the insect gut environment, where they may colonize through direct host-to-host transmission in natural settings. IMPORTANCE Flies in the genus Drosophila have become laboratory models for microbiota research, yet the bacteria commonly used in these experiments are rarely found in wild-caught flies and instead represent bacteria also present in the food. This study shows that an ecologically specialized Drosophila species possesses a distinctive microbiome, composed of bacterial types absent from the flies' natural food but widespread in other wild-caught insects. This study highlights the importance of fieldwork-informed microbiota research. Copyright © 2017 American Society for Microbiology.

A Distinctive and Host-Restricted Gut Microbiota in Populations of a Cactophilic Drosophila Species

PubMed Central

Carpinteyro-Ponce, Javier

2017-01-01

ABSTRACT Almost all animals possess gut microbial communities, but the nature of these communities varies immensely. For example, in social bees and mammals, the composition is relatively constant within species and is dominated by specialist bacteria that do not live elsewhere; in laboratory studies and field surveys of Drosophila melanogaster, however, gut communities consist of bacteria that are ingested with food and that vary widely among individuals and localities. We addressed whether an ecological specialist in its natural habitat has a microbiota dominated by gut specialists or by environmental bacteria. Drosophila nigrospiracula is a species that is endemic to the Sonoran Desert and is restricted to decaying tissues of two giant columnar cacti, Pachycereus pringlei (cardón cactus) and Carnegiea gigantea (saguaro cactus). We found that the D. nigrospiracula microbiota differs strikingly from that of the cactus tissue on which the flies feed. The most abundant bacteria in the flies are rare or completely absent in the cactus tissue and are consistently abundant in flies from different cacti and localities. Several of these fly-associated bacterial groups, such as the bacterial order Orbales and the genera Serpens and Dysgonomonas, have been identified in prior surveys of insects from the orders Hymenoptera, Coleoptera, Lepidoptera, and Diptera, including several Drosophila species. Although the functions of these bacterial groups are mostly unexplored, Orbales species studied in bees are known to break down plant polysaccharides and use the resulting sugars. Thus, these bacterial groups appear to be specialized to the insect gut environment, where they may colonize through direct host-to-host transmission in natural settings. IMPORTANCE Flies in the genus Drosophila have become laboratory models for microbiota research, yet the bacteria commonly used in these experiments are rarely found in wild-caught flies and instead represent bacteria also present in the food. This study shows that an ecologically specialized Drosophila species possesses a distinctive microbiome, composed of bacterial types absent from the flies' natural food but widespread in other wild-caught insects. This study highlights the importance of fieldwork-informed microbiota research. PMID:28939605

Revealing hidden insect-fungus interactions; moderately specialized, modular and anti-nested detritivore networks.

PubMed

Jacobsen, Rannveig M; Sverdrup-Thygeson, Anne; Kauserud, Håvard; Birkemoe, Tone

2018-04-11

Ecological networks are composed of interacting communities that influence ecosystem structure and function. Fungi are the driving force for ecosystem processes such as decomposition and carbon sequestration in terrestrial habitats, and are strongly influenced by interactions with invertebrates. Yet, interactions in detritivore communities have rarely been considered from a network perspective. In the present study, we analyse the interaction networks between three functional guilds of fungi and insects sampled from dead wood. Using DNA metabarcoding to identify fungi, we reveal a diversity of interactions differing in specificity in the detritivore networks, involving three guilds of fungi. Plant pathogenic fungi were relatively unspecialized in their interactions with insects inhabiting dead wood, while interactions between the insects and wood-decay fungi exhibited the highest degree of specialization, which was similar to estimates for animal-mediated seed dispersal networks in previous studies. The low degree of specialization for insect symbiont fungi was unexpected. In general, the pooled insect-fungus networks were significantly more specialized, more modular and less nested than randomized networks. Thus, the detritivore networks had an unusual anti-nested structure. Future studies might corroborate whether this is a common aspect of networks based on interactions with fungi, possibly owing to their often intense competition for substrate. © 2018 The Author(s).

Insights into the structure of plant-insect communities: Specialism and generalism in a regional set of non-pollinating fig wasp communities

NASA Astrophysics Data System (ADS)

Farache, F. H. A.; Cruaud, A.; Rasplus, J.-Y.; Cerezini, M. T.; Rattis, L.; Kjellberg, F.; Pereira, R. A. S.

2018-07-01

Insects show a multitude of symbiotic interactions that may vary in degree of specialization and structure. Gall-inducing insects and their parasitoids are thought to be relatively specialized organisms, but despite their ecological importance, the organization and structure of the interactions they establish with their hosts has seldom been investigated in tropical communities. Non-pollinating fig wasps (NPFW) are particularly interesting organisms for the study of ecological networks because most species strictly develop their offspring within fig inflorescences, and show a multitude of life history strategies. They can be gall-makers, cleptoparasites or parasitoids of pollinating or of other non-pollinating fig wasps. Here we analysed a set of non-pollinating fig wasp communities associated with six species of Ficus section Americanae over a wide area. This allowed us to investigate patterns of specialization in a diverse community composed of monophagous and polyphagous species. We observed that most NPFW species were cleptoparasites and parasitoids, colonizing figs several days after oviposition by pollinators. Most species that occurred in more than one host were much more abundant in a single preferential host, suggesting specialization. The food web established between wasps and figs shows structural properties that are typical of specific antagonistic relationships, especially of endophagous insect networks. Two species that occurred in all available hosts were highly abundant in the network, suggesting that in some cases generalized species can be more competitive than strict specialists. The Neotropical and, to a lesser extent, Afrotropical NPFW communities seem to be more generalized than other NPFW communities. However, evidence of host sharing in the Old World is quite limited, since most studies have focused on particular taxonomic groups (genera) of wasps instead of sampling the whole NPFW community. Moreover, the lack of quantitative information in previous studies prevents us from detecting patterns of host preferences in polyphagous species.

Biogenic volatile organic compounds in the Earth system.

PubMed

Laothawornkitkul, Jullada; Taylor, Jane E; Paul, Nigel D; Hewitt, C Nicholas

2009-01-01

Biogenic volatile organic compounds produced by plants are involved in plant growth, development, reproduction and defence. They also function as communication media within plant communities, between plants and between plants and insects. Because of the high chemical reactivity of many of these compounds, coupled with their large mass emission rates from vegetation into the atmosphere, they have significant effects on the chemical composition and physical characteristics of the atmosphere. Hence, biogenic volatile organic compounds mediate the relationship between the biosphere and the atmosphere. Alteration of this relationship by anthropogenically driven changes to the environment, including global climate change, may perturb these interactions and may lead to adverse and hard-to-predict consequences for the Earth system.

Nutritional and antinutritional composition of the five species of aquatic edible insects consumed in Manipur, India

PubMed Central

Shantibala, T.; Lokeshwari, R. K.; Debaraj, H.

2014-01-01

Abstract The people living in Manipur have a distinct identity, culture, and food habits. They have a prototype culture of eating insects. In our study, the nutritive contents of five potentially-edible aquatic insects, Lethocerus indicus (Lepeletier and Serville) (Hemiptera: Belostomatidae), Laccotrephes maculatus (F.) (Nepidae), Hydrophilus olivaceous (F.) (Coleoptera: Dytiscidae), Cybister tripunctatus (Olivier), and Crocothemis servilia (Drury) (Odonata: Libellulidae), were analyzed to inform consumers about the nutritional quality of the insects and the suggested quantity of their intake. A good amount of protein content and high gross energy was recorded among the insects. The results showed high levels of sodium, calcium, and magnesium present in the insects, indicating that they are a good source of minerals. Antinutritional properties of these insects were below 0.52%, which is a non-toxic level. Aquatic insects, such as C. tripunctatus , also possesses strong antioxidant activity (110 µg/mL). Therefore, these insects can play a major role in food security, health, and environment management. It is essential to cultivate edible insects to maintain their population sustainability. PMID:25373161

Patterns of species richness and diversity of insects associated with cucurbit fruits in the southern part of Cameroon.

PubMed

Mokam, Didi Gaëlle; Djiéto-Lordon, Champlain; Bilong Bilong, Charles-Félix

2014-01-01

Patterns of species diversity and community structure of insects associated with fruits of domesticated cucurbits were investigated from January 2009 to 2011 in three localities from two agroecological zones in the southern part of Cameroon. Rarefaction curves combined with nonparametric estimators of species richness were used to extrapolate species richness beyond our own data. Sampling efforts of over 92% were reached in each of the three study localities. Data collected revealed a total of 66 insect morphospecies belonging to 37 families and five orders, identified from a set of 57,510 insects. The orders Diptera (especially Tephritidae and Lonchaeidae) and Hymenoptera (mainly Braconidae and Eulophidae) were the most important, in terms of both abundance and species richness on the one hand, and effects on agronomic performance on the other. Values for both the species diversity (Shannon and Simpson) and the species richness indices (Margalef and Berger-Parker) calculated showed that the insect communities were species-rich but dominated, all to a similar extent, by five main species (including four fruit fly species and one parasitoid). Species abundance distributions in these communities ranged from the Zipf-Mandelbrot to Mandelbrot models. The communities are structured as tritrophic networks, including cucurbit fruits, fruit-feeding species (fruit flies) and carnivorous species (parasitoids). Within the guild of the parasitoids, about 30% of species, despite their low abundance, may potentially be of use in biological control of important pests. Our field data contribute in important ways to basic knowledge of biodiversity patterns in agrosystems and constitute baseline data for the planned implementation of biological control in Integrated Pest Management. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

Priority effects of early successional insects influence late successional fungi in dead wood.

PubMed

Jacobsen, Rannveig Margrete; Birkemoe, Tone; Sverdrup-Thygeson, Anne

2015-11-01

Community assembly is an integral process in all ecosystems, producing patterns of species distributions, biodiversity, and ecosystem functioning. Environmental filters and colonization history govern the assembly process, but their relative importance varies depending on the study system. Dead wood decomposition is a slow process, allowing decomposer communities to develop within a slowly changing substrate for decades. Despite this, there are few long-term studies of priority effects from colonization history in this ecosystem. In this study, we investigate the importance of insects in early succession of dead wood on the fungal community present one decade later. Sixty aspen trees were killed in two study landscapes, each tree producing one aspen high stump and log. Insects were sampled with flight interception traps during the first 4 years after tree death, and fungal fruiting bodies were registered in year twelve. We found positive priority effects of two fungivorous beetles, the sap beetle Glischrochilus quadripunctatus and the round fungus beetle Agathidium nigripenne, on the Artist's bracket (Ganoderma applanatum) and a positive priority effect of wood-boring beetles on the ascomycete Yellow fairy cup (Bisporella citrina). The Aspen bracket (Phellinus tremulae) did not respond to insects in early succession of the dead wood. Our results suggest that early successional insects can have significant, long-lasting effects on the late successional fungal community in dead wood. Also, the effect can be specific, with one fungus species depending on one or a few fungivorous beetle species. This has implications for decomposition and biodiversity in dead wood, as loss of early colonizing beetles may also affect the successional pathways they seem to initiate.

A 454 Survey Reveals the Community Composition and Core Microbiome of the Common Bed Bug (Cimex lectularius) across an Urban Landscape

PubMed Central

Meriweather, Matthew; Matthews, Sara; Rio, Rita; Baucom, Regina S.

2013-01-01

Elucidating the spatial dynamic and core constituents of the microbial communities found in association with arthropod hosts is of crucial importance for insects that may vector human or agricultural pathogens. The hematophagous Cimex lectularius (Hemiptera: Cimicidae), known as the human bed bug, has made a recent resurgence in North America, as well as worldwide, potentially owing to increased travel, climate change and resistance to insecticides. A comprehensive survey of the bed bug microbiome has not been performed to date, nor has an assessment of the spatial dynamics of its microbiome. Here we present a survey of internal and external bed bug microbial communities by amplifying the V4–V6 hypervariable region of the 16S rDNA gene region followed by 454 Titanium sequencing using 31 individuals from eight distinct collection locations obtained from residences in Cincinnati, OH. Across all samples, 97% of the microbial community is made up of two dominant OTUs, previously identified as the α-proteobacterium Wolbachia and an unnamed γ-proteobacterium from the Enterobacteriaceae. Microbial communities varied among host locations for measures of community diversity and exhibited structure according to collection location. This broad survey represents the most in-depth assessment, to date, of the microbes that associate with bed bugs. PMID:23585900

A 454 survey reveals the community composition and core microbiome of the common bed bug (Cimex lectularius) across an Urban Landscape.

PubMed

Meriweather, Matthew; Matthews, Sara; Rio, Rita; Baucom, Regina S

2013-01-01

Elucidating the spatial dynamic and core constituents of the microbial communities found in association with arthropod hosts is of crucial importance for insects that may vector human or agricultural pathogens. The hematophagous Cimex lectularius (Hemiptera: Cimicidae), known as the human bed bug, has made a recent resurgence in North America, as well as worldwide, potentially owing to increased travel, climate change and resistance to insecticides. A comprehensive survey of the bed bug microbiome has not been performed to date, nor has an assessment of the spatial dynamics of its microbiome. Here we present a survey of internal and external bed bug microbial communities by amplifying the V4-V6 hypervariable region of the 16S rDNA gene region followed by 454 Titanium sequencing using 31 individuals from eight distinct collection locations obtained from residences in Cincinnati, OH. Across all samples, 97% of the microbial community is made up of two dominant OTUs, previously identified as the α-proteobacterium Wolbachia and an unnamed γ-proteobacterium from the Enterobacteriaceae. Microbial communities varied among host locations for measures of community diversity and exhibited structure according to collection location. This broad survey represents the most in-depth assessment, to date, of the microbes that associate with bed bugs.

Wolbachia infection complexity among insects in the tropical rice-field community.

PubMed

Kittayapong, P; Jamnongluk, W; Thipaksorn, A; Milne, J R; Sindhusake, C

2003-04-01

Wolbachia are a group of intracellular bacteria that cause reproductive alterations in their arthropod hosts. Widely discordant host and Wolbachia phylogenies indicate that horizontal transmission of these bacteria among species sometimes occurs. A likely means of horizontal transfer is through the feeding relations of organisms within communities. Feeding interactions among insects within the rice-field insect community have been well documented in the past. Here, we present the results of a polymerase chain reaction-based survey and phylogenetic analysis of Wolbachia strains in the rice-field insect community of Thailand. Our field survey indicated that 49 of 209 (23.4%) rice-field insect species were infected with Wolbachia. Of the 49 infected species, 27 were members of two feeding complexes: (i) a group of 13 hoppers preyed on by 2 mirid species and parasitized by a fly species, and (ii) 2 lepidopteran pests parasitized by 9 wasp species. Wolbachia strains found in three hoppers, Recilia dorsalis, Nephotettix malayanus and Nisia nervosa, the two mirid predators, Cyrtorhinus lividipennis and Tytthus chinensis, and the fly parasitoid, Tomosvaryella subvirescens, were all in the same Wolbachia clade. In the second complex, the two lepidopteran pests, Cnaphalocrocis medinalis and Scirpophaga incertulas, were both infected with Wolbachia from the same clade, as was the parasitoid Tropobracon schoenobii. However, none of the other infected parasitoid species in this feeding complex was infected by Wolbachia from this clade. Mean (+/- SD) genetic distance of Wolbachia wsp sequences among interacting species pairs of the hopper feeding complex (0.118 +/- 0.091 nucleotide sequence differences), but not for the other two complexes, was significantly smaller than that between noninteracting species pairs (0.162 +/- 0.079 nucleotide sequence differences). Our results suggest that some feeding complexes, such as the hopper complex described here, could be an important means by which Wolbachia spreads among species within arthropod communities.

Colors of attraction: Modeling insect flight to light behavior.

PubMed

Donners, Maurice; van Grunsven, Roy H A; Groenendijk, Dick; van Langevelde, Frank; Bikker, Jan Willem; Longcore, Travis; Veenendaal, Elmar

2018-06-26

Light sources attract nocturnal flying insects, but some lamps attract more insects than others. The relation between the properties of a light source and the number of attracted insects is, however, poorly understood. We developed a model to quantify the attractiveness of light sources based on the spectral output. This model is fitted using data from field experiments that compare a large number of different light sources. We validated this model using two additional datasets, one for all insects and one excluding the numerous Diptera. Our model facilitates the development and application of light sources that attract fewer insects without the need for extensive field tests and it can be used to correct for spectral composition when formulating hypotheses on the ecological impact of artificial light. In addition, we present a tool allowing the conversion of the spectral output of light sources to their relative insect attraction based on this model. © 2018 Wiley Periodicals, Inc.

Variation in pollen-donor composition among pollinators in an entomophilous tree species, Castanea crenata, revealed by single-pollen genotyping.

PubMed

Hasegawa, Yoichi; Suyama, Yoshihisa; Seiwa, Kenji

2015-01-01

In plants, reproductive success is largely determined by the composition of pollen (i.e., self-pollen and outcross-pollen from near and distant pollen-donors) transported as a result of pollinator foraging behavior (e.g., pollen carryover). However, little evidence is available on how and to what extent the pollen carryover affects the pollen-donor composition and on which insect taxa are effective outcross-pollen transporters under field conditions. In this study, we explored roles of foraging behavior of insect pollinators on pollen-donor composition and subsequent reproductive success in a woody plant. We performed paternity analyses based on microsatellite genotyping of individual pollen grains found on diurnal pollinators (i.e., bumblebee, small bee, fly, small beetle, and honeybee) visiting Castanea crenata trees. The outcross-pollen rate was highest in bumblebees (66%), followed by small bees (35%), flies (31%), and small beetles (18%). The effective number of pollen donors, representing pollen carryover, was greater in bumblebees (9.71) than in flies (3.40), small bees (3.32), and small beetles (3.06). The high percentages of pollen from outside the plot on bumblebees (65.4%) and flies (71.2%) compared to small bees (35.3%) and small beetles (13.5%) demonstrated their longer pollen dispersal distances. All of the diurnal insects carried outcross-pollen grains for long distances via pollen carryover. This fact suggests that a wide range of insect taxa are potential outcross-pollen transporters for the self-incompatible C. crenata.

Mesoherbivores affect grasshopper communities in a megaherbivore-dominated South African savannah.

PubMed

van der Plas, Fons; Olff, Han

2014-06-01

African savannahs are among the few places on earth where diverse communities of mega- and meso-sized ungulate grazers dominate ecosystem functioning. Less conspicuous, but even more diverse, are the communities of herbivorous insects such as grasshoppers, which share the same food. Various studies investigated the community assembly of these groups separately, but it is poorly known how ungulate communities shape grasshopper communities. Here, we investigated how ungulate species of different body size alter grasshopper communities in a South African savannah. White rhino is the most abundant vertebrate herbivore in our study site. Other common mesoherbivores include buffalo, zebra and impala. We hypothesized that white rhinos would have greater impact than mesoherbivores on grasshopper communities. Using 10-year-old exclosures, at eight sites we compared the effects of ungulates on grasshopper communities in three nested treatments: (i) unfenced plots ('control plots') with all vertebrate herbivores present, (ii) plots with a low cable fence, excluding white rhino ('megaherbivore exclosures'), and (iii) plots with tall fences, excluding all herbivores larger than rodents ('complete ungulate exclosures'). In each plot, we collected data of vegetation structure, grass and grasshopper community composition. Complete ungulate exclosures contained 30% taller vegetation than megaherbivore exclosures and they were dominated by different grass and grasshopper species. Grasshoppers in complete ungulate exclosures were on average 3.5 mm longer than grasshoppers in megaherbivore exclosures, possibly due to changes in plant communities or vegetation structure. We conclude that surprisingly, in this megaherbivore hotspot, mesoherbivores, instead of megaherbivores, most strongly affect grasshopper communities.

Forest Management Intensity Affects Aquatic Communities in Artificial Tree Holes.

PubMed

Petermann, Jana S; Rohland, Anja; Sichardt, Nora; Lade, Peggy; Guidetti, Brenda; Weisser, Wolfgang W; Gossner, Martin M

2016-01-01

Forest management could potentially affect organisms in all forest habitats. However, aquatic communities in water-filled tree-holes may be especially sensitive because of small population sizes, the risk of drought and potential dispersal limitation. We set up artificial tree holes in forest stands subject to different management intensities in two regions in Germany and assessed the influence of local environmental properties (tree-hole opening type, tree diameter, water volume and water temperature) as well as regional drivers (forest management intensity, tree-hole density) on tree-hole insect communities (not considering other organisms such as nematodes or rotifers), detritus content, oxygen and nutrient concentrations. In addition, we compared data from artificial tree holes with data from natural tree holes in the same area to evaluate the methodological approach of using tree-hole analogues. We found that forest management had strong effects on communities in artificial tree holes in both regions and across the season. Abundance and species richness declined, community composition shifted and detritus content declined with increasing forest management intensity. Environmental variables, such as tree-hole density and tree diameter partly explained these changes. However, dispersal limitation, indicated by effects of tree-hole density, generally showed rather weak impacts on communities. Artificial tree holes had higher water temperatures (on average 2°C higher) and oxygen concentrations (on average 25% higher) than natural tree holes. The abundance of organisms was higher but species richness was lower in artificial tree holes. Community composition differed between artificial and natural tree holes. Negative management effects were detectable in both tree-hole systems, despite their abiotic and biotic differences. Our results indicate that forest management has substantial and pervasive effects on tree-hole communities and may alter their structure and functioning. We furthermore conclude that artificial tree-hole analogues represent a useful experimental alternative to test effects of changes in forest management on natural communities.

Forest Management Intensity Affects Aquatic Communities in Artificial Tree Holes

PubMed Central

Petermann, Jana S.; Rohland, Anja; Sichardt, Nora; Lade, Peggy; Guidetti, Brenda; Weisser, Wolfgang W.; Gossner, Martin M.

2016-01-01

Forest management could potentially affect organisms in all forest habitats. However, aquatic communities in water-filled tree-holes may be especially sensitive because of small population sizes, the risk of drought and potential dispersal limitation. We set up artificial tree holes in forest stands subject to different management intensities in two regions in Germany and assessed the influence of local environmental properties (tree-hole opening type, tree diameter, water volume and water temperature) as well as regional drivers (forest management intensity, tree-hole density) on tree-hole insect communities (not considering other organisms such as nematodes or rotifers), detritus content, oxygen and nutrient concentrations. In addition, we compared data from artificial tree holes with data from natural tree holes in the same area to evaluate the methodological approach of using tree-hole analogues. We found that forest management had strong effects on communities in artificial tree holes in both regions and across the season. Abundance and species richness declined, community composition shifted and detritus content declined with increasing forest management intensity. Environmental variables, such as tree-hole density and tree diameter partly explained these changes. However, dispersal limitation, indicated by effects of tree-hole density, generally showed rather weak impacts on communities. Artificial tree holes had higher water temperatures (on average 2°C higher) and oxygen concentrations (on average 25% higher) than natural tree holes. The abundance of organisms was higher but species richness was lower in artificial tree holes. Community composition differed between artificial and natural tree holes. Negative management effects were detectable in both tree-hole systems, despite their abiotic and biotic differences. Our results indicate that forest management has substantial and pervasive effects on tree-hole communities and may alter their structure and functioning. We furthermore conclude that artificial tree-hole analogues represent a useful experimental alternative to test effects of changes in forest management on natural communities. PMID:27187741

Hessian fly - associated bacteria: transmission, essentiality, and composition

USDA-ARS?s Scientific Manuscript database

Plant-feeding insects have been recently found to use microbes to manipulate host plants. Gall midges are one of the largest groups of insects that manipulate host plants extensively. In this study, we systematically analyzed for the first time bacteria associated with the Hessian fly (HF, Mayetio...

A phylogenetic community approach for studying termite communities in a West African savannah.

PubMed

Hausberger, Barbara; Korb, Judith

2015-10-01

Termites play fundamental roles in tropical ecosystems, and mound-building species in particular are crucial in enhancing species diversity, from plants to mammals. However, it is still unclear which factors govern the occurrence and assembly of termite communities. A phylogenetic community approach and null models of species assembly were used to examine structuring processes associated with termite community assembly in a pristine savannah. Overall, we did not find evidence for a strong influence of interspecific competition or environmental filtering in structuring these communities. However, the presence of a single species, the mound-building termite Macrotermes bellicosus, left a strong signal on structuring and led to clustered communities of more closely related species. Hence, this species changes the assembly rules for a whole community. Our results show the fundamental importance of a single insect species for community processes, suggesting that more attention to insect species is warranted when developing conservation strategies. © 2015 The Author(s).

Improved annotation of the insect vector of citrus greening disease: biocuration by a diverse genomics community

PubMed Central

Hosmani, Prashant S.; Villalobos-Ayala, Krystal; Miller, Sherry; Shippy, Teresa; Flores, Mirella; Rosendale, Andrew; Cordola, Chris; Bell, Tracey; Mann, Hannah; DeAvila, Gabe; DeAvila, Daniel; Moore, Zachary; Buller, Kyle; Ciolkevich, Kathryn; Nandyal, Samantha; Mahoney, Robert; Van Voorhis, Joshua; Dunlevy, Megan; Farrow, David; Hunter, David; Morgan, Taylar; Shore, Kayla; Guzman, Victoria; Izsak, Allison; Dixon, Danielle E.; Cridge, Andrew; Cano, Liliana; Cao, Xiaolong; Jiang, Haobo; Leng, Nan; Johnson, Shannon; Cantarel, Brandi L.; Richards, Stephen; English, Adam; Shatters, Robert G.; Childers, Chris; Chen, Mei-Ju; Hunter, Wayne; Cilia, Michelle; Mueller, Lukas A.; Munoz-Torres, Monica; Nelson, David; Poelchau, Monica F.; Benoit, Joshua B.; Wiersma-Koch, Helen; D’Elia, Tom; Brown, Susan J.

2017-01-01

Abstract The Asian citrus psyllid (Diaphorina citri Kuwayama) is the insect vector of the bacterium Candidatus Liberibacter asiaticus (CLas), the pathogen associated with citrus Huanglongbing (HLB, citrus greening). HLB threatens citrus production worldwide. Suppression or reduction of the insect vector using chemical insecticides has been the primary method to inhibit the spread of citrus greening disease. Accurate structural and functional annotation of the Asian citrus psyllid genome, as well as a clear understanding of the interactions between the insect and CLas, are required for development of new molecular-based HLB control methods. A draft assembly of the D. citri genome has been generated and annotated with automated pipelines. However, knowledge transfer from well-curated reference genomes such as that of Drosophila melanogaster to newly sequenced ones is challenging due to the complexity and diversity of insect genomes. To identify and improve gene models as potential targets for pest control, we manually curated several gene families with a focus on genes that have key functional roles in D. citri biology and CLas interactions. This community effort produced 530 manually curated gene models across developmental, physiological, RNAi regulatory and immunity-related pathways. As previously shown in the pea aphid, RNAi machinery genes putatively involved in the microRNA pathway have been specifically duplicated. A comprehensive transcriptome enabled us to identify a number of gene families that are either missing or misassembled in the draft genome. In order to develop biocuration as a training experience, we included undergraduate and graduate students from multiple institutions, as well as experienced annotators from the insect genomics research community. The resulting gene set (OGS v1.0) combines both automatically predicted and manually curated gene models. Database URL: https://citrusgreening.org/ PMID:29220441

A preliminary study on the insect fauna of Al-Baha Province, Saudi Arabia, with descriptions of two new species

PubMed Central

El-Hawagry, Magdi S.; Khalil, Mohammed W.; Sharaf, Mostafa R.; Hassan H. Fadl; Aldawood, Abdulrahman S.

2013-01-01

Abstract A preliminary study was carried out on the insect fauna of Al-Baha Province, south-western part of Saudi Arabia. A total number of 582 species and subspecies (few identified only to the genus level) belonging to 129 families and representing 17 orders were recorded. Two of these species are described as new, namely: Monomorium sarawatensis Sharaf & Aldawood, sp. n. [Formicidae, Hymenoptera] and Anthrax alruqibi El-Hawagry sp. n. [Bombyliidae, Diptera]. Another eight species are recorded for the first time in Saudi Arabia, namely: Xiphoceriana arabica (Uvarov, 1922) [Pamphagidae, Orthoptera], Pyrgomorpha conica (Olivier, 1791) [Pyrgomorphidae, Orthoptera], Catopsilia florella (Fabricius, 1775) [Pieridae, Lepidoptera], Anthrax chionanthrax (Bezzi, 1926) [Bombyliidae, Diptera], Spogostylum near tripunctatum Pallas in Wiedemann, 1818 [Bombyliidae, Diptera], Cononedys dichromatopa (Bezzi, 1925) [Bombyliidae, Diptera], Mydas sp. [Mydidae, Diptera], and Hippobosca equina Linnaeus, 1758 [Hippoboscidae, Diptera]. Al-Baha Province is divided by huge and steep Rocky Mountains into two main sectors, a lowland coastal plain at the west, known as “Tihama”, and a mountainous area with an elevation of 1500 to 2450 m above sea level at the east, known as “Al-Sarat or Al-Sarah” which form a part of Al-Sarawat Mountains range. Insect species richness in the two sectors (Tihama and Al-Sarah) was compared, and the results showed that each of the two sectors of Al-Baha Province has a unique insect community. The study generally concluded that the insect faunal composition in Al-Baha Province has an Afrotropical flavor, with the Afrotropical elements predominant, and a closer affiliation to the Afrotropical region than to the Palearctic region or the Eremic zone. Consequently, we tend to agree with those biogeographers who consider that parts of the Arabian Peninsula, including Al-Baha Province, should be included in the Afrotropical region rather than in the Palaearctic region or the Eremic zone. PMID:23794807

Structural differences in gut bacteria communities in developmental stages of natural populations of Lutzomyia evansi from Colombia's Caribbean coast.

PubMed

Vivero, Rafael José; Jaramillo, Natalia Gil; Cadavid-Restrepo, Gloria; Soto, Sandra I Uribe; Herrera, Claudia Ximena Moreno

2016-09-13

Lutzomyia evansi, a phlebotomine insect endemic to Colombia's Caribbean coast, is considered to be the main vector of visceral and cutaneous leishmaniasis in the region. Although insects of this species can harbor pathogenic and non-pathogenic microorganisms in their intestinal microbiota, there is little information available about the diversity of gut bacteria present in Lutzomyia evansi. In this study, conventional microbiological methods and molecular tools were used to assess the composition of bacterial communities associated with Lutzomyia evansi guts in immature and adult stages of natural populations from the department of Sucre (Caribbean coast of Colombia). Sand flies were collected from two locations (peri-urban and jungle biotype) in the Department of Sucre (Caribbean coast of Colombia). A total of 752 Lutzomyia evansi intestines were dissected. In this study, 125 bacterial strains were isolated from different culture media (LB Agar, MacConkey Agar). Different methods were used for bacterial identification, including ribosomal intergenic spacer analysis (RISA) and analysis of the 16S rRNA and gyrB gene sequences. The genetic profiles of the bacterial populations were generated and temporal temperature gradient gel electrophoresis (TTGE) was used to compare them with total gut DNA. We also used PCR and DNA sequence analysis to determine the presence of Wolbachia endosymbiont bacteria and Leishmania parasites. The culture-dependent technique showed that the dominant intestinal bacteria isolated belong to Acinetobacter, Enterobacter, Pseudomonas, Ochrobactrum, Shinella and Paenibacillus in the larval stage; Lysobacter, Microbacterium, Streptomyces, Bacillus and Rummeliibacillus in the pupal stage; and Staphylococcus, Streptomyces, Brevibacterium, Acinetobacter, Enterobacter and Pantoea in the adult stage. Statistical analysis revealed significant differences between the fingerprint patterns of the PCR-TTGE bands in bacterial communities from immature and adult stages. Additionally, differences were found in bacterial community structure in fed females, unfed females, males and larvae. The intestinal bacteria detected by PCR-TTGE were Enterobacter cloacae and Bacillus thuringiensis, which were present in different life stages of Lu. evansi, and Burkholderia cenocepacia and Bacillus gibsonii, which were detected only in the larval stage. Wolbachia and Leishmania were not detected in gut samples of Lutzomyia evansi. The analyses conducted using microbiological and molecular approaches indicated significant variations in the bacterial communities associated with the gut of Lu. evansi, depending on the developmental stage and food source. We propose that these elements affect microbial diversity in L. evansi guts and may in turn influence pathogen transmission to humans bitten by this insect.

Bacterial Symbionts in Lepidoptera: Their Diversity, Transmission, and Impact on the Host

PubMed Central

Paniagua Voirol, Luis R.; Frago, Enric; Kaltenpoth, Martin; Hilker, Monika; Fatouros, Nina E.

2018-01-01

The insect’s microbiota is well acknowledged as a “hidden” player influencing essential insect traits. The gut microbiome of butterflies and moths (Lepidoptera) has been shown to be highly variable between and within species, resulting in a controversy on the functional relevance of gut microbes in this insect order. Here, we aim to (i) review current knowledge on the composition of gut microbial communities across Lepidoptera and (ii) elucidate the drivers of the variability in the lepidopteran gut microbiome and provide an overview on (iii) routes of transfer and (iv) the putative functions of microbes in Lepidoptera. To find out whether Lepidopterans possess a core gut microbiome, we compared studies of the microbiome from 30 lepidopteran species. Gut bacteria of the Enterobacteriaceae, Bacillaceae, and Pseudomonadaceae families were the most widespread across species, with Pseudomonas, Bacillus, Staphylococcus, Enterobacter, and Enterococcus being the most common genera. Several studies indicate that habitat, food plant, and age of the host insect can greatly impact the gut microbiome, which contributes to digestion, detoxification, or defense against natural enemies. We mainly focus on the gut microbiome, but we also include some examples of intracellular endosymbionts. These symbionts are present across a broad range of insect taxa and are known to exert different effects on their host, mostly including nutrition and reproductive manipulation. Only two intracellular bacteria genera (Wolbachia and Spiroplasma) have been reported to colonize reproductive tissues of Lepidoptera, affecting their host’s reproduction. We explore routes of transmission of both gut microbiota and intracellular symbionts and have found that these microbes may be horizontally transmitted through the host plant, but also vertically via the egg stage. More detailed knowledge about the functions and plasticity of the microbiome in Lepidoptera may provide novel leads for the control of lepidopteran pest species. PMID:29636736

Increasing evidence that bats actively forage at wind turbines

PubMed Central

Foo, Cecily F.; Bennett, Victoria J.; Korstian, Jennifer M.; Schildt, Alison J.; Williams, Dean A.

2017-01-01

Although the ultimate causes of high bat fatalities at wind farms are not well understood, several lines of evidence suggest that bats are attracted to wind turbines. One hypothesis is that bats would be attracted to turbines as a foraging resource if the insects that bats prey upon are commonly present on and around the turbine towers. To investigate the role that foraging activity may play in bat fatalities, we conducted a series of surveys at a wind farm in the southern Great Plains of the US from 2011–2016. From acoustic monitoring we recorded foraging activity, including feeding buzzes indicative of prey capture, in the immediate vicinity of turbine towers from all six bat species known to be present at this site. From insect surveys we found Lepidoptera, Coleoptera, and Orthoptera in consistently high proportions over several years suggesting that food resources for bats were consistently available at wind turbines. We used DNA barcoding techniques to assess bat diet composition of (1) stomach contents from 47 eastern red bat (Lasiurus borealis) and 24 hoary bat (Lasiurus cinereus) carcasses collected in fatality searches, and (2) fecal pellets from 23 eastern red bats that were found on turbine towers, transformers, and tower doors. We found that the majority of the eastern red bat and hoary bat stomachs, the two bat species most commonly found in fatality searches at this site, were full or partially full, indicating that the bats were likely killed while foraging. Although Lepidoptera and Orthoptera dominated the diets of these two bat species, both consumed a range of prey items with individual bats having from one to six insect species in their stomachs at the time of death. The prey items identified from eastern red bat fecal pellets showed similar results. A comparison of the turbine insect community to the diet analysis results revealed that the most abundant insects at wind turbines, including terrestrial insects such as crickets and several important crop pests, were also commonly eaten by eastern red and hoary bats. Collectively, these findings suggest that bats are actively foraging around wind turbines and that measures to minimize bat fatalities should be broadly implemented at wind facilities. PMID:29114441

Increasing evidence that bats actively forage at wind turbines.

PubMed

Foo, Cecily F; Bennett, Victoria J; Hale, Amanda M; Korstian, Jennifer M; Schildt, Alison J; Williams, Dean A

2017-01-01

Although the ultimate causes of high bat fatalities at wind farms are not well understood, several lines of evidence suggest that bats are attracted to wind turbines. One hypothesis is that bats would be attracted to turbines as a foraging resource if the insects that bats prey upon are commonly present on and around the turbine towers. To investigate the role that foraging activity may play in bat fatalities, we conducted a series of surveys at a wind farm in the southern Great Plains of the US from 2011-2016. From acoustic monitoring we recorded foraging activity, including feeding buzzes indicative of prey capture, in the immediate vicinity of turbine towers from all six bat species known to be present at this site. From insect surveys we found Lepidoptera, Coleoptera, and Orthoptera in consistently high proportions over several years suggesting that food resources for bats were consistently available at wind turbines. We used DNA barcoding techniques to assess bat diet composition of (1) stomach contents from 47 eastern red bat ( Lasiurus borealis ) and 24 hoary bat ( Lasiurus cinereus ) carcasses collected in fatality searches, and (2) fecal pellets from 23 eastern red bats that were found on turbine towers, transformers, and tower doors. We found that the majority of the eastern red bat and hoary bat stomachs, the two bat species most commonly found in fatality searches at this site, were full or partially full, indicating that the bats were likely killed while foraging. Although Lepidoptera and Orthoptera dominated the diets of these two bat species, both consumed a range of prey items with individual bats having from one to six insect species in their stomachs at the time of death. The prey items identified from eastern red bat fecal pellets showed similar results. A comparison of the turbine insect community to the diet analysis results revealed that the most abundant insects at wind turbines, including terrestrial insects such as crickets and several important crop pests, were also commonly eaten by eastern red and hoary bats. Collectively, these findings suggest that bats are actively foraging around wind turbines and that measures to minimize bat fatalities should be broadly implemented at wind facilities.

Insect herbivores change the outcome of plant competition through both inter- and intraspecific processes.

PubMed

Kim, Tania N; Underwood, Nora; Inouye, Brian D

2013-08-01

Insect herbivores can affect plant abundance and community composition, and theory suggests that herbivores influence plant communities by altering interspecific interactions among plants. Because the outcome of interspecific interactions is influenced by the per capita competitive ability of plants, density dependence, and intrinsic rates of increase, measuring herbivore effects on all these processes is necessary to understand the mechanisms by which herbivores influence plant communities. We fit alternative competition models to data from a response surface experiment conducted over four years to examine how herbivores affected the outcome of competition between two perennial plants, Solidago altissima and Solanum carolinense. Within a growing season, herbivores reduced S. carolinense plant size but did not affect the size of S. altissima, which exhibited compensatory growth. Across seasons, herbivores did not affect S. carolinense density or biomass but reduced both the density and population growth of S. altissima. The best-fit models indicated that the effects of herbivores varied with year. In some years, herbivores increased the per capita competitive effect of S. altissima on S. carolinense; in other years, herbivores influenced the intrinsic rate of increase of S. altissima. We examined possible herbivore effects on the longer-term outcome of competition (over the time scale of a typical old-field habitat), using simulations based on the best-fit models. In the absence of herbivores, plant coexistence was observed. In the presence of herbivores, S. carolinense was excluded by S. altissima in 72.3% of the simulations. We demonstrate that herbivores can influence the outcome of competition through changes in both per capita competitive effects and intrinsic rates of increase. We discuss the implications of these results for ecological succession and biocontrol.

Formation of Mesoherpetobionts Communities on a Reclamated Coal Open Pit Dump

NASA Astrophysics Data System (ADS)

Luzyanin, Sergey; Eremeeva, Natalya

2017-11-01

The structure of the mesoherpetobionts arthropod communities of the reclamated dump of the Krasnobrodsky coal pit (Kemerovo region, Russia) has been studied. It was established that the pioneer grouping of mesoherpetobionts arthropod represented by classes of Chilopoda, Arachnida and Insecta-Ectognatha has been formed on the dump for two years after the soil deposition. From the Arachnida, the species of the order Aranei are the most active in the stocking of the dumps. From the class Chilopoda, the species of Lithobiomorpha appear the first on the dump. Insects from the following three orders, Heteroptera, Hymenoptera and especially Coleoptera take the main part in the expansion of dumps and the formation of primary communities. Among the Coleoptera, the beetles of the family of Carabidae (44 species, dynamic density 22.9 specimens/10 trapped per day) dominate. From them, small or medium-sized species are mainly involved in stocking the dumps. There are significant differences in the complexes of ground dump carabid beetles in comparison with the control group, differing in species composition of dominant species, species richness and species diversity parameters

Toxicological characteristics of edible insects in China: A historical review.

PubMed

Gao, Yu; Wang, Di; Xu, Meng-Lei; Shi, Shu-Sen; Xiong, Jin-Feng

2018-04-10

Edible insects are ideal food sources, which contain important nutrients and health-promoting compounds. With a rapid development of industrial insect farming, insect-derived food is a novel and emerging food industry. Edible insects have been traditionally consumed in various communities, while continuously gaining relevance in today's society; however, they currently remain underutilized. Although there are a large number of literature on edible insects, these literature primarily focus on the nutritional value edible insects. The toxicity assessment data of edible insects remain incomprehensive, especially for the new national standard that is currently in effect; and many data and conclusions are not accurately specified/reported. Therefore, we performed a literature review and summarized the data on the toxicological assessment of edible insects in China. The review first describes the research progress on safety toxicological assessment, and then offers references regarding the development of 34 edible insect species in China. These data can be a platform for the development of future toxicological assessment strategies, which can be carried out by a multidisciplinary team, possibly consisting of food engineers, agronomists, farmers, and so on, to improve the acceptability of edible insects. Copyright © 2018 Elsevier Ltd. All rights reserved.

The effects of crop intensification on the diversity of native pollinator communities

USDA-ARS?s Scientific Manuscript database

Recent increases in agricultural conversion are leading to a decline in native grasslands and natural resources critical for beneficial insects. However, little is known regarding how these regional changes are affecting pollinator diversity. Insect pollinators were collected at 12 locations in Broo...

Making Connections with Insect Royalty.

ERIC Educational Resources Information Center

Hobbie, Ann

2000-01-01

Describes a one-month sixth grade class activity with monarch butterflies called Monarch in the Classroom. Students learn about insects, especially the class material butterflies, including their life cycle, eating habits, migration, and how they overwinter. The lesson plan covers sorting animals, focusing on features, analyzing the community for…

Effects of weed cover composition on insect pest and natural enemy abundance in a field of Dracaena marginata (Asparagales: Asparagaceae) in Costa Rica.

PubMed

Sadof, Clifford S; Linkimer, Mildred; Hidalgo, Eduardo; Casanoves, Fernando; Gibson, Kevin; Benjamin, Tamara J

2014-04-01

Weeds and their influence on pest and natural enemy populations were studied on a commercial ornamental farm during 2009 in the Atlantic Zone of Costa Rica. A baseline survey of the entire production plot was conducted in February, along a 5 by 5 m grid to characterize and map initial weed communities of plants, cicadellids, katydids, and armored scales. In total, 50 plant species from 21 families were found. Seven weed treatments were established to determine how weed manipulations would affect communities of our targeted pests and natural enemies. These treatments were selected based on reported effects of specific weed cover on herbivorous insects and natural enemies, or by their use by growers as a cover crop. Treatments ranged from weed-free to being completely covered with endemic species of weeds. Although some weed treatments changed pest abundances, responses differed among arthropod pests, with the strongest effects observed for Caldwelliola and Empoasca leafhoppers. Removal of all weeds increased the abundance of Empoasca, whereas leaving mostly cyperacaeous weeds increased the abundance of Caldwelliola. Weed manipulations had no effect on the abundance of katydid and scale populations. No weed treatment reduced the abundance of all three of the target pests. Differential responses of the two leafhopper species to the same weed treatments support hypotheses, suggesting that noncrop plants can alter the abundance of pests through their effects on arthropod host finding and acceptance, as well as their impacts on natural enemies.

Bat and bird diversity along independent gradients of latitude and tree composition in European forests.

PubMed

Charbonnier, Yohan M; Barbaro, Luc; Barnagaud, Jean-Yves; Ampoorter, Evy; Nezan, Julien; Verheyen, Kris; Jactel, Hervé

2016-10-01

Species assemblages are shaped by local and continental-scale processes that are seldom investigated together, due to the lack of surveys along independent gradients of latitude and habitat types. Our study investigated changes in the effects of forest composition and structure on bat and bird diversity across Europe. We compared the taxonomic and functional diversity of bat and bird assemblages in 209 mature forest plots spread along gradients of forest composition and vertical structure, replicated in 6 regions spanning from the Mediterranean to the boreal biomes. Species richness and functional evenness of both bat and bird communities were affected by the interactions between latitude and forest composition and structure. Bat and bird species richness increased with broadleaved tree cover in temperate and especially in boreal regions but not in the Mediterranean where they increased with conifer abundance. Bat species richness was lower in forests with smaller trees and denser understorey only in northern regions. Bird species richness was not affected by forest structure. Bird functional evenness increased in younger and denser forests. Bat functional evenness was also influenced by interactions between latitude and understorey structure, increasing in temperate forests but decreasing in the Mediterranean. Covariation between bat and bird abundances also shifted across Europe, from negative in southern forests to positive in northern forests. Our results suggest that community assembly processes in bats and birds of European forests are predominantly driven by abundance and accessibility of feeding resources, i.e., insect prey, and their changes across both forest types and latitudes.

Stable Isotope Systematics in Grasshopper Assemblages Along an Elevation Gradient, Colorado

NASA Astrophysics Data System (ADS)

Kohn, M. J.; Evans, S.; Dean, J.; Nufio, C.

2012-12-01

Insects comprise over three quarters of all animal species, yet studies of body water isotopic composition are limited to only the cockroach, the hoverfly, and chironomid flies. These studies suggest that oxygen and hydrogen isotopic compositions in body water are primarily controlled by dietary water sources, with modification from respiratory and metabolic processes. In particular, outward diffusion of isotopically depleted water vapor through insect spiracles at low humidity enriches residual body water in 18O and 2H (D). Stable isotope compositions (δ18O and δD) also respond to gradients in elevation and humidity, but these influences remain poorly understood. In this study, we measured grasshopper body water and local vegetation isotopic compositions along an elevation gradient in Colorado to evaluate three hypotheses: 1) Insect body water isotopic composition is directly related to food source water composition 2) Water vapor transport alters body water isotopic compositions relative to original diet sources, and 3) Elevation gradients influence isotopic compositions in insect body water. Thirty-five species of grasshopper were collected from 14 locations in Colorado grasslands, ranging in elevation from 450 to 800 meters (n=131). Body water was distilled from previously frozen grasshopper specimens using a vacuum extraction line, furnaces (90 °C), and liquid nitrogen traps. Water samples were then analyzed for δ18O and δD on an LGR Liquid Water Isotope Analyzer, housed in the Department of Geosciences, Boise State University. Grasshopper body water isotopic compositions show wide variation, with values ranging between -76.64‰ to +42.82‰ in δD and -3.06‰ to +26.78‰ in δ18O. Precipitation δ18O values over the entire Earth excluding the poles vary by approximately 30‰, comparable to the total range measured in our single study area. Most grasshopper values deviate from the global meteoric water line relating δ18O and δD in precipitation, consistent with evaporative enrichment in food (plants) due to plant transpiration. However, grasshopper body water from any given location is further enriched in 18O and D relative to food. Isotopic values decrease slightly with increasing elevation, but some specific grasshopper species appear more sensitive to elevation. Overall, evaporative enrichment of 18O and D in this relatively dry environment appears the strongest factors influencing grasshopper compositions.

Functional Process Zones Characterizing Aquatic Insect Communities in Streams of the Brazilian Cerrado.

PubMed

Godoy, B S; Simião-Ferreira, J; Lodi, S; Oliveira, L G

2016-04-01

Stream ecology studies see to understand ecological dynamics in lotic systems. The characterization of streams into Functional Process Zones (FPZ) has been currently debated in stream ecology because aquatic communities respond to functional processes of river segments. Therefore, we tested if different functional process zones have different number of genera and trophic structure using the aquatic insect community of Neotropical streams. We also assessed whether using physical and chemical variables may complement the approach of using FPZ to model communities of aquatic insects in Cerrado streams. This study was conducted in 101 streams or rivers from the central region of the state of Goiás, Brazil. We grouped the streams into six FPZ associated to size of the river system, presence of riparian forest, and riverbed heterogeneity. We used Bayesian models to compare number of genera and relative frequency of the feeding groups between FPZs. Streams classified in different FPZs had a different number of genera, and the largest and best preserved rivers had an average of four additional genera. Trophic structure exhibited low variability among FPZs, with little difference both in the number of genera and in abundance. Using functional process zones in Cerrado streams yielded good results for Ephemeroptera, Plecoptera, and Trichoptera communities. Thus, species distribution and community structure in the river basin account for functional processes and not necessarily for the position of the community along a longitudinal dimension of the lotic system.

Insect Gut Bacterial Diversity Determined by Environmental Habitat, Diet, Developmental Stage, and Phylogeny of Host

PubMed Central

Yun, Ji-Hyun; Roh, Seong Woon; Whon, Tae Woong; Jung, Mi-Ja; Kim, Min-Soo; Park, Doo-Sang; Yoon, Changmann; Nam, Young-Do; Kim, Yun-Ji; Choi, Jung-Hye; Kim, Joon-Yong; Shin, Na-Ri; Kim, Sung-Hee; Lee, Won-Jae

2014-01-01

Insects are the most abundant animals on Earth, and the microbiota within their guts play important roles by engaging in beneficial and pathological interactions with these hosts. In this study, we comprehensively characterized insect-associated gut bacteria of 305 individuals belonging to 218 species in 21 taxonomic orders, using 454 pyrosequencing of 16S rRNA genes. In total, 174,374 sequence reads were obtained, identifying 9,301 bacterial operational taxonomic units (OTUs) at the 3% distance level from all samples, with an average of 84.3 (±97.7) OTUs per sample. The insect gut microbiota were dominated by Proteobacteria (62.1% of the total reads, including 14.1% Wolbachia sequences) and Firmicutes (20.7%). Significant differences were found in the relative abundances of anaerobes in insects and were classified according to the criteria of host environmental habitat, diet, developmental stage, and phylogeny. Gut bacterial diversity was significantly higher in omnivorous insects than in stenophagous (carnivorous and herbivorous) insects. This insect-order-spanning investigation of the gut microbiota provides insights into the relationships between insects and their gut bacterial communities. PMID:24928884

Same host-plant, different sterols: variation in sterol metabolism in an insect herbivore community.

PubMed

Janson, Eric M; Grebenok, Robert J; Behmer, Spencer T; Abbot, Patrick

2009-11-01

Insects lack the ability to synthesize sterols de novo, which are required as cell membrane inserts and as precursors for steroid hormones. Herbivorous insects typically utilize cholesterol as their primary sterol. However, plants rarely contain cholesterol, and herbivorous insects must, therefore, produce cholesterol by metabolizing plant sterols. Previous studies have shown that insects generally display diversity in phytosterol metabolism. Despite the biological importance of sterols, there has been no investigation of their metabolism in a naturally occurring herbivorous insect community. Therefore, we determined the neutral sterol profile of Solidago altissima L., six taxonomically and ecologically diverse herbivorous insect associates, and the fungal symbiont of one herbivore. Our results demonstrated that S. altissima contained Delta(7)-sterols (spinasterol, 22-dihydrospinasterol, avenasterol, and 24-epifungisterol), and that 85% of the sterol pool existed in a conjugated form. Despite feeding on a shared host plant, we observed significant variation among herbivores in terms of their qualitative tissue sterol profiles and significant variation in the cholesterol content. Cholesterol was absent in two dipteran gall-formers and present at extremely low levels in a beetle. Cholesterol content was highly variable in three hemipteran phloem feeders; even species of the same genus showed substantial differences in their cholesterol contents. The fungal ectosymbiont of a dipteran gall former contained primarily ergosterol and two ergosterol precursors. The larvae and pupae of the symbiotic gall-former lacked phytosterols, phytosterol metabolites, or cholesterol, instead containing an ergosterol metabolite in addition to unmetabolized ergosterol and erogsterol precursors, thus demonstrating the crucial role that a fungal symbiont plays in their nutritional ecology. These data are discussed in the context of sterol physiology and metabolism in insects, and the potential ecological and evolutionary implications.

Variation in Pollen-Donor Composition among Pollinators in an Entomophilous Tree Species, Castanea crenata, Revealed by Single-Pollen Genotyping

PubMed Central

Hasegawa, Yoichi; Suyama, Yoshihisa; Seiwa, Kenji

2015-01-01

Background In plants, reproductive success is largely determined by the composition of pollen (i.e., self-pollen and outcross-pollen from near and distant pollen-donors) transported as a result of pollinator foraging behavior (e.g., pollen carryover). However, little evidence is available on how and to what extent the pollen carryover affects the pollen-donor composition and on which insect taxa are effective outcross-pollen transporters under field conditions. In this study, we explored roles of foraging behavior of insect pollinators on pollen-donor composition and subsequent reproductive success in a woody plant. Methods We performed paternity analyses based on microsatellite genotyping of individual pollen grains found on diurnal pollinators (i.e., bumblebee, small bee, fly, small beetle, and honeybee) visiting Castanea crenata trees. Results The outcross-pollen rate was highest in bumblebees (66%), followed by small bees (35%), flies (31%), and small beetles (18%). The effective number of pollen donors, representing pollen carryover, was greater in bumblebees (9.71) than in flies (3.40), small bees (3.32), and small beetles (3.06). The high percentages of pollen from outside the plot on bumblebees (65.4%) and flies (71.2%) compared to small bees (35.3%) and small beetles (13.5%) demonstrated their longer pollen dispersal distances. Conclusions All of the diurnal insects carried outcross-pollen grains for long distances via pollen carryover. This fact suggests that a wide range of insect taxa are potential outcross-pollen transporters for the self-incompatible C. crenata. PMID:25793619

Herbivore species richness, composition and community structure mediate predator richness effects and top-down control of herbivore biomass.

PubMed

Wilby, Andrew; Orwin, Kate H

2013-08-01

Changes in predator species richness can have important consequences for ecosystem functioning at multiple trophic levels, but these effects are variable and depend on the ecological context in addition to the properties of predators themselves. Here, we report an experimental study to test how species identity, community attributes, and community structure at the herbivore level moderate the effects of predator richness on ecosystem functioning. Using mesocosms containing predatory insects and aphid prey, we independently manipulated species richness at both predator and herbivore trophic levels. Community structure was also manipulated by changing the distribution of herbivore species across two plant species. Predator species richness and herbivore species richness were found to negatively interact to influence predator biomass accumulation, an effect which is hypothesised to be due to the breakdown of functional complementarity among predators in species-rich herbivore assemblages. The strength of predator suppression of herbivore biomass decreased as herbivore species richness and distribution across host plants increased, and positive predator richness effects on herbivore biomass suppression were only observed in herbivore assemblages of relatively low productivity. In summary, the study shows that the species richness, productivity and host plant distribution of prey communities can all moderate the general influence of predators and the emergence of predator species richness effects on ecosystem functioning.

Nonrandom Composition of Flower Colors in a Plant Community: Mutually Different Co-Flowering Natives and Disturbance by Aliens

PubMed Central

Makino, Takashi T.; Yokoyama, Jun

2015-01-01

When pollinators use flower color to locate food sources, a distinct color can serve as a reproductive barrier against co-flowering species. This anti-interference function of flower color may result in a community assembly of plant species displaying mutually different flower colors. However, such color dispersion is not ubiquitous, suggesting a variable selection across communities and existence of some opposing factors. We conducted a 30-week study in a plant community and measured the floral reflectances of 244 species. The reflectances were evaluated in insect color spaces (bees, swallowtails, and flies), and the dispersion was compared with random expectations. We found that co-existing colors were overdispersed for each analyzed pollinator type, and this overdispersion was statistically significant for bees. Furthermore, we showed that exclusion of 32 aliens from the analysis significantly increased the color dispersion of native flowers in every color space. This result indicated that aliens disturbed a native plant–pollinator network via similarly colored flowers. Our results demonstrate the masking effects of aliens in the detection of color dispersion of native flowers and that variations in pollinator vision yield different outcomes. Our results also support the hypothesis that co-flowering species are one of the drivers of color diversification and affect the community assembly. PMID:26650121

Impact of Stand Management Practices on Beetle Diversity

Treesearch

Stephen P. Cook

2004-01-01

Abstract - Insects are useful indicators of change within ecosystems because of their abundance, richness and functional importance. Stand management practices impact the insect community within a forest. Therefore, the objective of the project is to determine the impact of various stand management practices on the diversity of beetles within...

Estimating benthic secondary production from aquatic insect emergence in streams affected by mountaintop removal coal mining, West Virginia USA

EPA Science Inventory

Mountaintop removal and valley fill (MTR/VF) coal mining recountours the Appalachian landscape, buries headwater stream channels, and degrades downstream water quality. The goal of this study was to compare benthic community production estimates, based on seasonal insect emergen...

Colonization, succession, and nutrition of macrobenthic assemblages in a restored wetland at Tijuana Estuary, California

NASA Astrophysics Data System (ADS)

Moseman, Serena M.; Levin, Lisa A.; Currin, Carolyn; Forder, Charlotte

2004-08-01

Modes of colonization, the successional trajectory, and trophic recovery of a macrofaunal community were analyzed over 19 months in the Friendship marsh, a 20-acre restored wetland in Tijuana Estuary, California. Traditional techniques for quantifying macrofaunal communities were combined with emerging stable isotopic approaches for evaluation of trophic recovery, making comparisons with a nearby natural Spartina foliosa habitat. Life history-based predictions successfully identified major colonization modes, although most taxa employed a variety of tactics for colonizing the restored marsh. The presence of S. foliosa did not seem to affect macrofaunal colonization or succession at the scale of this study. However, soil organic matter content in the restored marsh was positively correlated with insect densities, and high initial salinities may have limited the success of early colonists. Total macrofaunal densities recovered to natural marsh levels after 14 months and diversity, measured as species richness and the Shannon index ( H'), was comparable to the natural marsh by 19 months. Some compositional disparities between the natural and created communities persisted after 19 months, including lower percentages of surface-feeding polychaetes ( Polydora spp.) and higher percentages of dipteran insects and turbellarians in the Friendship marsh. As surficial structural similarity of infaunal communities between the Friendship and natural habitat was achieved, isotopic analyses revealed a simultaneous trajectory towards recovery of trophic structure. Enriched δ 13C signatures of benthic microalgae and infauna, observed in the restored marsh shortly after establishment compared to natural Spartina habitat, recovered after 19 months. However, the depletion in δ 15N signatures of macrofauna in the Friendship marsh indicated consumption of microalgae, particularly nitrogen-fixing cyanobacteria, while macroalgae and Spartina made a larger contribution to macrofaunal diets in the natural habitat. Future successional studies must continue to develop and employ novel combinations of techniques for evaluating structural and functional recovery of disturbed and created habitats.

Invasive pests—insects and diseases

Treesearch

Donald A. Duerr; Paul A. Mistretta

2013-01-01

Key FindingsNonnative pest species have increasing impacts in the South regardless of climate change, patterns of land ownership, or changes in the composition of vegetation.“New” nonnative invasive insects and diseases will have serious impacts on southern forests over the next 50 years. Some species such as emerald ash borer...

Annual variation in decomposition and insect succession at a periurban area of central Iberian Peninsula.

PubMed

Díaz-Aranda, Luisa M; Martín-Vega, Daniel; Gómez-Gómez, Aída; Cifrián, Blanca; Baz, Arturo

2018-05-01

The variation in decomposition and insect succession among the four seasons of one year was studied for the first time in a periurban area of central Spain. During the winter trial, the carcasses showed corification, a cadaveric preservation phenomenon which apparently leaded to a significant delay in decomposition processes. The composition of the insect fauna breeding on carcasses changed significantly between trials. Active decay was mainly driven by Calliphoridae (Diptera) larvae in every season except in winter trial, when larvae of Thanatophilus species (Coleoptera: Silphidae) were the main consumers of soft tissues. Advanced decay was characterized by the occurrence of Dermestidae, Silphidae, Cleridae, Nitidulidae (Coleoptera) and Piophilidae (Diptera) larvae. Differences in the species composition in comparison with other regions of the Iberian Peninsula were also observed. The current paper provides baseline and preliminary information on the insect succession on carrion in central Spain, as well as a starting point for further research on forensic entomology in this region. Copyright © 2018 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Impacts of Insect Herbivores on Plant Populations.

PubMed

Myers, Judith H; Sarfraz, Rana M

2017-01-31

Apparent feeding damage by insects on plants is often slight. Thus, the influences of insect herbivores on plant populations are likely minor. The role of insects on host-plant populations can be elucidated via several methods: stage-structured life tables of plant populations manipulated by herbivore exclusion and seed-addition experiments, tests of the enemy release hypothesis, studies of the effects of accidentally and intentionally introduced insect herbivores, and observations of the impacts of insect species that show outbreak population dynamics. These approaches demonstrate that some, but not all, insect herbivores influence plant population densities. At times, insect-feeding damage kills plants, but more often, it reduces plant size, growth, and seed production. Plant populations for which seed germination is site limited will not respond at the population level to reduced seed production. Insect herbivores can influence rare plant species and need to be considered in conservation programs. Alterations due to climate change in the distributions of insect herbivores indicate the possibility of new influences on host plants. Long-term studies are required to show if density-related insect behavior stabilizes plant populations or if environmental variation drives most temporal fluctuations in plant densities. Finally, insects can influence plant populations and communities through changing the diversity of nonhost species, modifying nutrient fluxes, and rejuvenating over mature forests.

Trophic Interactions in Louisiana Salt Marshes: Combining Stomach Content, Stable Isotope, and Fatty Acid Approaches

NASA Astrophysics Data System (ADS)

Lopez-Duarte, P. C.; Able, K.; Fodrie, J.; McCann, M. J.; Melara, S.; Noji, C.; Olin, J.; Pincin, J.; Plank, K.; Polito, M. J.; Jensen, O.

2016-02-01

Multiple studies conducted over five years since the 2010 Macondo oil spill in the Gulf of Mexico indicate that oil impacts vary widely among taxonomic groups. For instance, fishes inhabiting the marsh surface show no clear differences in either community composition or population characteristics between oiled and unoiled sites, despite clear evidence of physiological impacts on individual fish. In contrast, marsh insects and spiders are sensitive to the effects of hydrocarbons. Both insects and spiders are components of the marsh food web and represent an important trophic link between marsh plants and higher trophic levels. Because differences in oil impacts throughout the marsh food web have the potential to significantly alter food webs and energy flow pathways and reduce food web resilience, our goal is to quantify differences in marsh food webs between oiled and unoiled sites to test the hypothesis that oiling has resulted in simpler and less resilient food webs. Diets and food web connections were quantified through a combination of stomach content, stable isotope, and fatty acid analysis. The combination of these three techniques provides a more robust approach to quantifying trophic relationships than any of these methods alone. Stomach content analysis provides a detailed snapshot of diets, while fatty acid and stable isotopes reflect diets averaged over weeks to months. Initial results focus on samples collected in May 2015 from a range of terrestrial and aquatic consumer species, including insects, mollusks, crustaceans, and piscivorous fishes.

Influence of habitat and land use on the assemblages of ephemeroptera, plecoptera, and trichoptera in neotropical streams.

PubMed

Amaral, Pedro Henrique Monteiro do; Silveira, Lidimara Souza da; Rosa, Beatriz Figueiraujo Jabour Vescovi; Oliveira, Vívian Campos de; Alves, Roberto da Gama

2015-01-01

Insects of the orders Ephemeroptera, Plecoptera, and Trichoptera (EPT) are often used to assess the conditions of aquatic environments, but few studies have examined the differences in these communities between riffles and pools. Our objective was to test whether riffles shelter greater richness and abundance of EPT, as well as to assess the sensitivity of these insects for detecting impacts from different land uses in streams in southeastern Brazil. Samples were collected in the dry season of 2012 with a Surber sampler in riffles and pools of nine streams (forest, pasture, and urban areas). Principal component analysis distinguished the streams according to different land uses as a function of percentage of plant cover and water oxygenation level and showed partial distinction between riffles and pools as a function of current speed and percentage of ultrafine sand. Detrended correspondence analysis indicated the distinction in EPT composition between riffles and pools, except in urban streams. The results of this study confirm the expected differences in the EPT fauna structure between riffles and pools, especially in forest and pasture environments. The individual metrics of riffle and pool assemblages showed significantly different responses to land use. Therefore, we suggest individual sampling of riffles and pools, since the metrics of these assemblages' insects can differ between these habitats and influence the results of assessments in low-order streams. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

Purification, composition, and physical properties of a thermal hysteresis "antifreeze" protein from larvae of the beetle, Tenebrio molitor.

PubMed

Tomchaney, A P; Morris, J P; Kang, S H; Duman, J G

1982-02-16

Proteins which produce a thermal hysteresis (difference between the freezing and melting points) in aqueous solution are well-known for their antifreeze activity in polar marine fishes. Much less is known about the biology and biochemistry of similar antifreeze proteins found in certain insects. A thermal hysteresis protein was purified from cold acclimated larvae of the beetle, Tenebrio molitor, by using ethanol fractionation, DEAE ion-exchange chromatography, gel filtration, and high-pressure liquid chromatography. The purified protein had a molecular mass of 17 000 daltons and its N terminus was lysine. The amino acid composition of the antifreeze protein contained more hydrophilic amino acids than the fish antifreezes. This is consistent with the compositions of previously purified insect thermal hysteresis proteins. However, the percentage of hydrophilic amino acids in this Tenebrio antifreeze protein was considerably less than that of other insect thermal hysteresis proteins. The freezing point depressing activity of the Tenebrio antifreeze was less than that of fish proteins and glycoproteins at low protein concentrations but was greater at high protein concentrations.

Extraction and characterization of gelatin from two edible Sudanese insects and its applications in ice cream making.

PubMed

Mariod, Abdalbasit Adam; Fadul, Hadia

2015-07-01

Three methods were used for extraction of gelatin from two insects, melon bug (Coridius viduatus) and sorghum bug (Agonoscelis versicoloratus versicoloratus). Extraction of insect gelatin using hot water gave higher yield reached up to 3.0%, followed by mild acid extraction which gave 1.5% and distilled water extraction which gave only 1.0%, respectively. The obtained gelatins were characterized by FTIR and the spectra of insect's gelatin seem to be similar when compared with commercial gelatin. Amide II bands of gelatins from melon and sorghum bug appeared around at 1542-1537 cm(-1). Slight differences in the amino acid composition of gelatin extracted from the two insects were observed. Ice cream was made by using 0.5% insect's gelatin and compared with that made using 0.5% commercial gelatin as stabilizing agent. The properties of the obtained ice cream produced using insects gelatin were significantly different when compared with that made using commercial gelatin. © The Author(s) 2014.

Reprint of "Stable hydrogen and carbon isotopic compositions of long-chain (C21-C33) n-alkanes and n-alkenes in insects"

NASA Astrophysics Data System (ADS)

Chikaraishi, Yoshito; Kaneko, Masanori; Ohkouchi, Naohiko

2013-06-01

We report the molecular and stable isotopic (δD and δ13C) compositions of long-chain n-alkanes in common insects including the cabbage butterfly, swallowtail, wasp, hornet, grasshopper, and ladybug. Insect n-alkanes are potential candidates of the contamination of soil and sedimentary n-alkanes that are believed to be derived from vascular plant waxes. Long-chain n-alkanes (range C21-33; maximum C23-C29) are found to be abundant in the insects (31-781 μg/dry g), with a carbon preference index (CPI) of 5.1-31.5 and an average chain length (ACL) of 24.9-29.3. The isotopic compositions (mean ± 1σ, n = 33) of the n-alkanes are -195 ± 16‰ for hydrogen and -30.6 ± 2.4‰ for carbon. The insect n-alkanes are depleted in D by approximately 30-40‰ compared with wax n-alkanes from C3 (-155 ± 25‰) and C4 vascular plants (-167 ± 13‰), whereas their δ13C values fall between those of C3 (-36.2 ± 2.4‰) and C4 plants (-20.3 ± 2.4‰). Thus, the contribution of insect-derived n-alkanes to soil and sediment could potentially shift δD records of n-alkanes toward more negative values and potentially muddle the assumed original C3/C4 balance in the δ13C records of the soil and sedimentary n-alkanes. n-Alkenes are also found in three insects (swallowtail, wasp and hornet). They are more depleted in D relative to the same carbon numbered n-alkanes (δDn-alkene - δDn-alkane = -17 ± 16‰), but the δ13C values are almost identical to those of the n-alkanes (δ13Cn-alkene - δ13Cn-alkane = 0.1 ± 0.2‰). These results suggest that these n-alkenes are desaturated products of the same carbon numbered n-alkanes.

Stable hydrogen and carbon isotopic compositions of long-chain (C21-C33) n-alkanes and n-alkenes in insects

NASA Astrophysics Data System (ADS)

Chikaraishi, Yoshito; Kaneko, Masanori; Ohkouchi, Naohiko

2012-10-01

We report the molecular and stable isotopic (δD and δ13C) compositions of long-chain n-alkanes in common insects including the cabbage butterfly, swallowtail, wasp, hornet, grasshopper, and ladybug. Insect n-alkanes are potential candidates of the contamination of soil and sedimentary n-alkanes that are believed to be derived from vascular plant waxes. Long-chain n-alkanes (range C21-33; maximum C23-C29) are found to be abundant in the insects (31-781 μg/dry g), with a carbon preference index (CPI) of 5.1-31.5 and an average chain length (ACL) of 24.9-29.3. The isotopic compositions (mean ± 1σ, n = 33) of the n-alkanes are -195 ± 16‰ for hydrogen and -30.6 ± 2.4‰ for carbon. The insect n-alkanes are depleted in D by approximately 30-40‰ compared with wax n-alkanes from C3 (-155 ± 25‰) and C4 vascular plants (-167 ± 13‰), whereas their δ13C values fall between those of C3 (-36.2 ± 2.4‰) and C4 plants (-20.3 ± 2.4‰). Thus, the contribution of insect-derived n-alkanes to soil and sediment could potentially shift δD records of n-alkanes toward more negative values and potentially muddle the assumed original C3/C4 balance in the δ13C records of the soil and sedimentary n-alkanes. n-Alkenes are also found in three insects (swallowtail, wasp and hornet). They are more depleted in D relative to the same carbon numbered n-alkanes (δDn-alkene - δDn-alkane = -17 ± 16‰), but the δ13C values are almost identical to those of the n-alkanes (δ13Cn-alkene - δ13Cn-alkane = 0.1 ± 0.2‰). These results suggest that these n-alkenes are desaturated products of the same carbon numbered n-alkanes.

Long-term deer exclosure alters soil properties, plant traits, understory plant community and insect herbivory, but not the functional relationships among them.

PubMed

Stephan, Jörg G; Pourazari, Fereshteh; Tattersdill, Kristina; Kobayashi, Takuya; Nishizawa, Keita; De Long, Jonathan R

2017-07-01

Evidence of the indirect effects of increasing global deer populations on other trophic levels is increasing. However, it remains unknown if excluding deer alters ecosystem functional relationships. We investigated how sika deer exclosure after 18 years changed soil conditions, the understory plant community, the traits of a dominant understory plant (Sasa palmata), herbivory by three insect-feeding guilds, and the functional relationships between these properties. Deer absence decreased understory plant diversity, but increased soil organic matter and ammonium concentrations. When deer were absent, S. palmata plants grew taller, with more, larger, and tougher leaves with higher polyphenol concentrations. Deer absence led to higher leaf area consumed by all insect guilds, but lower insect herbivory per plant due to increased resource abundance (i.e., a dilution effect). This indicates that deer presence strengthened insect herbivory per plant, while in deer absence plants compensated losses with growth. Because plant defenses increased in the absence of deer, higher insect abundances in deer absence may have outweighed lower consumption rates. A path model revealed that the functional relationships between the measured properties were similar between deer absence versus presence. Taken together, deer altered the abiotic and biotic environment, thereby changing insect herbivory, which might impact upon nutrient cycling and primary productivity. These results provide evidence that deer can alter interactions between trophic levels, but that functional relationships between certain ecosystem components may remain constant. These findings highlight the need to consider how increasing global deer populations can have cascade effects that might alter ecosystem dynamics.

Difficulties in relating Cd concentrations in the predatory insect Chaoborus to those of its prey in nature

USGS Publications Warehouse

Croteau, M.-N.; Hare, L.; Tessier, A.

2003-01-01

Because Chaoborus larvae take up most of their cadmium (Cd) from food, we tested the hypothesis that Cd concentrations in this insect are directly related to those in their planktonic prey. We measured Cd in Chaoborus and in Zooplankton collected from 24 eastern Canadian lakes varying widely in their Cd concentrations. Cd concentrations in the predator were not correlated with those in bulk zooplankton, whether separated into size fractions liable to be eaten by Chaoborus or not. In highly acidic lakes, Cd concentrations in Chaoborus did not respond to increases in zooplankton Cd because of either competition between H and Cd ions at Cd absorption sites in the predator's gut or differences in prey community composition between highly acidic and circumneutral lakes. Relationships between Cd in Chaoborus and in its potential prey were stronger when we used Cd concentrations for specific crustacean taxa in a mechanistic model. We conclude that predictive relationships between metal concentrations in predators and their prey are likely to be strongest if the subset of prey consumed by the predator has been characterized and if this information is used in a bioaccumulation model.

Bacterial community diversity and variation in spray water sources and the tomato fruit surface

PubMed Central

2011-01-01

Background Tomato (Solanum lycopersicum) consumption has been one of the most common causes of produce-associated salmonellosis in the United States. Contamination may originate from animal waste, insects, soil or water. Current guidelines for fresh tomato production recommend the use of potable water for applications coming in direct contact with the fruit, but due to high demand, water from other sources is frequently used. We sought to describe the overall bacterial diversity on the surface of tomato fruit and the effect of two different water sources (ground and surface water) when used for direct crop applications by generating a 454-pyrosequencing 16S rRNA dataset of these different environments. This study represents the first in depth characterization of bacterial communities in the tomato fruit surface and the water sources commonly used in commercial vegetable production. Results The two water sources tested had a significantly different bacterial composition. Proteobacteria was predominant in groundwater samples, whereas in the significantly more diverse surface water, abundant phyla also included Firmicutes, Actinobacteria and Verrucomicrobia. The fruit surface bacterial communities on tomatoes sprayed with both water sources could not be differentiated using various statistical methods. Both fruit surface environments had a high representation of Gammaproteobacteria, and within this class the genera Pantoea and Enterobacter were the most abundant. Conclusions Despite the major differences observed in the bacterial composition of ground and surface water, the season long use of these very different water sources did not have a significant impact on the bacterial composition of the tomato fruit surface. This study has provided the first next-generation sequencing database describing the bacterial communities living in the fruit surface of a tomato crop under two different spray water regimes, and therefore represents an important step forward towards the development of science-based metrics for Good Agricultural Practices. PMID:21510867

Atmospheric oxygen level and the evolution of insect body size.

PubMed

Harrison, Jon F; Kaiser, Alexander; VandenBrooks, John M

2010-07-07

Insects are small relative to vertebrates, possibly owing to limitations or costs associated with their blind-ended tracheal respiratory system. The giant insects of the late Palaeozoic occurred when atmospheric PO(2) (aPO(2)) was hyperoxic, supporting a role for oxygen in the evolution of insect body size. The paucity of the insect fossil record and the complex interactions between atmospheric oxygen level, organisms and their communities makes it impossible to definitively accept or reject the historical oxygen-size link, and multiple alternative hypotheses exist. However, a variety of recent empirical findings support a link between oxygen and insect size, including: (i) most insects develop smaller body sizes in hypoxia, and some develop and evolve larger sizes in hyperoxia; (ii) insects developmentally and evolutionarily reduce their proportional investment in the tracheal system when living in higher aPO(2), suggesting that there are significant costs associated with tracheal system structure and function; and (iii) larger insects invest more of their body in the tracheal system, potentially leading to greater effects of aPO(2) on larger insects. Together, these provide a wealth of plausible mechanisms by which tracheal oxygen delivery may be centrally involved in setting the relatively small size of insects and for hyperoxia-enabled Palaeozoic gigantism.

An endoparasitoid Cretaceous fly and the evolution of parasitoidism.

PubMed

Zhang, Qingqing; Zhang, Junfeng; Feng, Yitao; Zhang, Haichun; Wang, Bo

2016-02-01

Parasitoidism is a key innovation in insect evolution, and parasitoid insects, nowadays, play a significant role in structuring ecological communities. Despite their diversity and ecological impact, little is known about the early evolution and ecology of parasitoid insects, especially parasitoid true flies (Diptera). Here, we describe a bizarre fly, Zhenia xiai gen. et sp. nov., from Late Cretaceous Burmese amber (about 99 million years old) that represents the latest occurrence of the family Eremochaetidae. Z. xiai is an endoparasitoid insect as evidenced by a highly developed, hypodermic-like ovipositor formed by abdominal tergites VIII + IX that was used for injecting eggs into hosts and enlarged tridactylous claws supposedly for clasping hosts. Our results suggest that eremochaetids are among the earliest definite records of parasitoid insects. Our findings reveal an unexpected morphological specialization of flies and broaden our understanding of the evolution and diversity of ancient parasitoid insects.

Sterile-Insect Methods for Control of Mosquito-Borne Diseases: An Analysis

PubMed Central

Benedict, Mark; Bellini, Romeo; Clark, Gary G.; Dame, David A.; Service, Mike W.; Dobson, Stephen L.

2010-01-01

Abstract Effective vector control, and more specifically mosquito control, is a complex and difficult problem, as illustrated by the continuing prevalence (and spread) of mosquito-transmitted diseases. The sterile insect technique and similar methods control certain agricultural insect pest populations in a species-specific, environmentally sound, and effective manner; there is increased interest in applying this approach to vector control. Such an approach, like all others in use and development, is not a one-size-fits-all solution, and will be more appropriate in some situations than others. In addition, the proposed release of pest insects, and more so genetically modified pest insects, is bound to raise questions in the general public and the scientific community as to such a method's efficacy, safety, and sustainability. This article attempts to address these concerns and indicate where sterile-insect methods are likely to be useful for vector control. PMID:19725763

An endoparasitoid Cretaceous fly and the evolution of parasitoidism

NASA Astrophysics Data System (ADS)

Zhang, Qingqing; Zhang, Junfeng; Feng, Yitao; Zhang, Haichun; Wang, Bo

2016-02-01

Parasitoidism is a key innovation in insect evolution, and parasitoid insects, nowadays, play a significant role in structuring ecological communities. Despite their diversity and ecological impact, little is known about the early evolution and ecology of parasitoid insects, especially parasitoid true flies (Diptera). Here, we describe a bizarre fly, Zhenia xiai gen. et sp. nov., from Late Cretaceous Burmese amber (about 99 million years old) that represents the latest occurrence of the family Eremochaetidae. Z. xiai is an endoparasitoid insect as evidenced by a highly developed, hypodermic-like ovipositor formed by abdominal tergites VIII + IX that was used for injecting eggs into hosts and enlarged tridactylous claws supposedly for clasping hosts. Our results suggest that eremochaetids are among the earliest definite records of parasitoid insects. Our findings reveal an unexpected morphological specialization of flies and broaden our understanding of the evolution and diversity of ancient parasitoid insects.

Imaging and Laser Spectroscopy Investigation of Insect Wings

NASA Astrophysics Data System (ADS)

Shiver, Tegan; Lawhead, Carlos; Anderson, Josiah; Cooper, Nathan; Ujj, Laszlo; Pall Life Sciences Collaboration

2014-03-01

Measuring the surface morphology and chemical composition of insect wings is important to understand the extreme mechanical properties and the biophysical functionalities of the wings. We have measured the image of the membrane of the cicada (genus Tibicen) wing with the help of Scanning Electron Microscopy (SEM). The results confirm the existing periodic structure of the wing measured previously. The SEM imaging can be used to measure the surface morphology of any insect species wings. The physical surface structure of the cicada wing is an example of a new class of biomaterials that can kill bacteria on contact. In order to identify the chemical composition of the wing, we have measured the vibrational spectra of the wing's membrane (Raman and CARS). The measured spectra are consistent with the original assumption that the wing membrane is composed of protein, wax, and chitin. The results of these studies can be used to make artificial materials in the future.

Metamorphosis of a butterfly-associated bacterial community.

PubMed

Hammer, Tobin J; McMillan, W Owen; Fierer, Noah

2014-01-01

Butterflies are charismatic insects that have long been a focus of biological research. They are also habitats for microorganisms, yet these microbial symbionts are little-studied, despite their likely importance to butterfly ecology and evolution. In particular, the diversity and composition of the microbial communities inhabiting adult butterflies remain uncharacterized, and it is unknown how the larval (caterpillar) and adult microbiota compare. To address these knowledge gaps, we used Illumina sequencing of 16S rRNA genes from internal bacterial communities associated with multiple life stages of the neotropical butterfly Heliconius erato. We found that the leaf-chewing larvae and nectar- and pollen-feeding adults of H. erato contain markedly distinct bacterial communities, a pattern presumably rooted in their distinct diets. Larvae and adult butterflies host relatively small and similar numbers of bacterial phylotypes, but few are common to both stages. The larval microbiota clearly simplifies and reorganizes during metamorphosis; thus, structural changes in a butterfly's bacterial community parallel those in its own morphology. We furthermore identify specific bacterial taxa that may mediate larval and adult feeding biology in Heliconius and other butterflies. Although male and female Heliconius adults differ in reproductive physiology and degree of pollen feeding, bacterial communities associated with H. erato are not sexually dimorphic. Lastly, we show that captive and wild individuals host different microbiota, a finding that may have important implications for the relevance of experimental studies using captive butterflies.

Metamorphosis of a Butterfly-Associated Bacterial Community

PubMed Central

Hammer, Tobin J.; McMillan, W. Owen; Fierer, Noah

2014-01-01

Butterflies are charismatic insects that have long been a focus of biological research. They are also habitats for microorganisms, yet these microbial symbionts are little-studied, despite their likely importance to butterfly ecology and evolution. In particular, the diversity and composition of the microbial communities inhabiting adult butterflies remain uncharacterized, and it is unknown how the larval (caterpillar) and adult microbiota compare. To address these knowledge gaps, we used Illumina sequencing of 16S rRNA genes from internal bacterial communities associated with multiple life stages of the neotropical butterfly Heliconius erato. We found that the leaf-chewing larvae and nectar- and pollen-feeding adults of H. erato contain markedly distinct bacterial communities, a pattern presumably rooted in their distinct diets. Larvae and adult butterflies host relatively small and similar numbers of bacterial phylotypes, but few are common to both stages. The larval microbiota clearly simplifies and reorganizes during metamorphosis; thus, structural changes in a butterfly's bacterial community parallel those in its own morphology. We furthermore identify specific bacterial taxa that may mediate larval and adult feeding biology in Heliconius and other butterflies. Although male and female Heliconius adults differ in reproductive physiology and degree of pollen feeding, bacterial communities associated with H. erato are not sexually dimorphic. Lastly, we show that captive and wild individuals host different microbiota, a finding that may have important implications for the relevance of experimental studies using captive butterflies. PMID:24466308

Effects of shelterwood management on flower-visiting insects and their floral resources

Treesearch

Jessica E. Fultz

2005-01-01

Habitat alteration can affect pollinating-insect community structure, decreasing the efficiency of pollinators on which many agricultural and natural ecosystems rely. Within the Tenderfoot Creek Experimental Forest (TCEF), located in the Little Belt Mountains of Central Montana, two different types of silvicultural techniques, even and group shelterwood, were applied...

Exotic forest insects and residential property values

Treesearch

Thomas P. Holmes; Elizabeth A. Murphy; Kathleen P. Bell

2006-01-01

This paper presents a case study of the economic damages to homeowners in a northern New Jersey community due to an exotic forest insect-the hemlock woolly adelgid. Hedonic property value methods are used to estimate the effect of hemlock health on property values. A statistically significant relationship between hemlock health and residential property values is...

Analyzing the movement of an invasive weevil (Polydrusus sericeus) using stable Isotopes

Treesearch

Joanne Lund; Paula Marquardt; William Jr. Mattson

2010-01-01

To better understand the response of insect populations to increasing CO2 and O3, we used ratios of stable carbon isotopes (d 13C) to trace the movement of an invasive insect in mixed tree communities grown under different air quality conditions. Polydrusus sericeus is a non-native...

Impacts of insect biological control on soil N transformations in Tamarix-invaded ecosystems in the Great Basin, USA

USDA-ARS?s Scientific Manuscript database

Understanding the impacts of insect biological control of Tamarix spp. on soil nitrogen (N) transformations is important because changes to N supply could alter plant community succession. We investigated short-term and longer-term impacts of herbivory by the northern tamarisk beetle (Diorhabda cari...

Impacts of insect biological control on soil N transformations in Tamarix-invaded ecosystems in the Great Basin

USDA-ARS?s Scientific Manuscript database

Understanding the impacts of insect biological control of Tamarix spp. on soil nitrogen (N) transformations is important because changes to N supply could alter plant community succession. We investigated short-term and longer-term impacts of herbivory by the northern tamarisk beetle (Diorhabda cari...

Within gut physiochemical variation does not correspond to distinct resident fungal and bacterial communities in the tree-killing xylophage, Anolophora glabripennis

USDA-ARS?s Scientific Manuscript database

Insect guts harbor diverse microbial assemblages that can be influenced by multiple factors, including gut physiology and interactions by the host with its environment. The Asian longhorned beetle (ALB; Anoplophora glabripennis) is an invasive tree–killing insect, which harbors a diverse consortium ...

Can Landscape-scale management influence insect outbreak dynamics? A natural experiment for eastern spruce budworm

Treesearch

Brian R. Sturtevant; V. Quinn; L.E. Robert; D. Kneeshaw; P. James; M.-J. Fortin; P. Wolter; P. Townsend; B. Cooke; D. Anderson

2010-01-01

The balance of evidence suggests forest insect outbreaks today are more damaging than ever because of changes in forest composition and structure induced by fire suppression and post-harvest proliferation of tree species intolerant to herbivory. We hypothesized that landscape connectivity of acceptable host trees increases defoliator population connectivity, altering...

Invasions by two non-native insects alter regional forest species composition and successional trajectories

Treesearch

Randall S. Morin; Andrew M. Liebhold

2015-01-01

While invasions of individual non-native phytophagous insect species are known to affect growth and mortality of host trees, little is known about how multiple invasions combine to alter forest dynamics over large regions. In this study we integrate geographical data describing historical invasion spread of the hemlock woolly adelgid, Adelges tsugae...

Spread of beech bark disease in the eastern United States and its relationship to regional forest composition

Treesearch

Randall S. Morin; Andrew M. Liebhold; Patrick C. Tobin; Kurt W. Gottschalk; Eugene Luzader

2007-01-01

Beech bark disease (BBD) is an insect-fungus complex involving the beech scale insect (Cryptococcus fagisuga Lind.) and one of two canker fungi. Beech scale was introduced to Halifax, Nova Scotia around 1890, presumably with the fungus Neonectria coccinea var. faginata Lohm. The disease has subsequently spread...

Capturing community context of human response to forest disturbance by insects: a multi-method assessment

Treesearch

Hua Qin; Courtney G. Flint

2010-01-01

The socioeconomic and environmental features of local places (community context) influence the relationship between humans and their physical environment. In times of environmental disturbance, this community context is expected to influence human perceptual and behavioral responses. Residents from nine Colorado communities experiencing a large outbreak of mountain...

Community structure of aquatic insects in the karstic Jadro River in Croatia.

PubMed

Rađa, Biljana; Santić, Mate

2014-04-19

This study focused on the aquatic insect community in the longitudinal gradient and temporal scales of the Jadro River. The river was sampled for a period of ten years (2000- 2010), four times per year through the various seasons, along the river course. Sampling stations were selected in the upper, middle, and downstream parts of the river. A total of 21,852 specimens of aquatic insects belonging to six orders were obtained. The species determination confirmed 27 different species in the river. The data were analyzed by the multivariate methodologies of correspondence analysis and cluster analysis (unweighted pair group method with arithmetic mean) using the similarity index of Morosita for all ten years. Canonical correspondence analysis was applied to the data to check which of the mesured physicochemical variables significantly explained community variation. According to those data, significant variables for the upper station were water temperature and dissolved oxygen, and chlorides was the significant variable for the lower stations. This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.

Regulation of Hydrolytic Enzyme Activity in Aquatic Microbial Communities Hosted by Carnivorous Pitcher Plants.

PubMed

Young, Erica B; Sielicki, Jessica; Grothjan, Jacob J

2018-04-20

Carnivorous pitcher plants Sarracenia purpurea host diverse eukaryotic and bacterial communities which aid in insect prey digestion, but little is known about the functional processes mediated by the microbial communities. This study aimed to connect pitcher community diversity with functional nutrient transformation processes, identifying bacterial taxa, and measuring regulation of hydrolytic enzyme activity in response to prey and alternative nutrient sources. Genetic analysis identified diverse bacterial taxa known to produce hydrolytic enzyme activities. Chitinase, protease, and phosphatase activities were measured using fluorometric assays. Enzyme activity in field pitchers was positively correlated with bacterial abundance, and activity was suppressed by antibiotics suggesting predominantly bacterial sources of chitinase and protease activity. Fungi, algae, and rotifers observed could also contribute enzyme activity, but fresh insect prey released minimal chitinase activity. Activity of chitinase and proteases was upregulated in response to insect additions, and phosphatase activity was suppressed by phosphate additions. Particulate organic P in prey was broken down, appearing as increasing dissolved organic and inorganic P pools within 14 days. Chitinase and protease were not significantly suppressed by availability of dissolved organic substrates, though organic C and N stimulated bacterial growth, resulting in elevated enzyme activity. This comprehensive field and experimental study show that pitcher plant microbial communities dynamically regulate hydrolytic enzyme activity, to digest prey nutrients to simpler forms, mediating biogeochemical nutrient transformations and release of nutrients for microbial and host plant uptake.

Honeybee nutrition is linked to landscape composition

PubMed Central

Donkersley, Philip; Rhodes, Glenn; Pickup, Roger W; Jones, Kevin C; Wilson, Kenneth

2014-01-01

Declines in insect pollinators in Europe have been linked to changes in land use. Pollinator nutrition is dependent on floral resources (i.e., nectar and pollen), which are linked to landscape composition. Here, we present a stratified analysis of the nutritional composition of beebread in managed honeybee hives with a view to examining potential sources of variation in its nutritional composition. Specifically, we tested the hypothesis that beebread composition correlates with local land use and therefore available floral resources. The results demonstrated that the starch, lipid, and moisture contents of beebread are all highly conserved across hives, whereas levels of protein and nonreducing sugar increased as the year progressed, reducing sugars, however, decreased during the first half of the year and then increased toward the end. Local land use around hives was quantified using data from the Countryside Survey 2007 Land Cover Map. Bee-bread protein content was negatively correlated with increasing levels of arable and horticultural farmland surrounding hives and positively correlated with the cover of natural grasslands and broadleaf woodlands. Reducing sugar content was also positively correlated with the amount of broad-leaved woodland in a 3 Km² radius from the hives. Previous studies on a range of invertebrates, including honeybees, indicate that dietary protein intake may have a major impact on correlates of fitness, including longevity and immune function. The finding that beebread protein content correlates with land use suggests that landscape composition may impact on insect pollinator well-being and provides a link between landscape and the nutritional ecology of socially foraging insects in a way not previously considered. PMID:25505544

Composition of an avian guild in spatially structured habitats supports a competition–colonization trade-off

PubMed Central

Rodríguez, Alejandro; Jansson, Gunnar; Andrén, Henrik

2007-01-01

Assuming better colonization abilities of inferior competitors, the competition–colonization trade-off (CCTO) is one of the hypotheses that explains spatial variation of species composition in fragmented habitats. Whereas this mechanism may structure some plant and insect communities, ecologists have failed to document its operation in other natural systems, and its generality has been questioned. We combined fieldwork and published data to study the composition of a guild of passerines (Parus cristatus, Parus montanus, Parus ater and Regulus regulus) inhabiting 10 landscapes that differed in the amount of forest habitat. The species were ordered in a stable, well-defined competitive hierarchy, and the dispersal ability of each species was inversely correlated with its position in this hierarchy. In functionally continuous landscapes, superior competitors occupied most fragments and all guild members commonly occurred. The relative incidences of superior and inferior competitors were reversed, and differences amplified, in landscapes where patches were physically (distance) or functionally (matrix hardness) isolated. We found little support for two competing hypotheses, namely reduced habitat quality in isolated patches and lower abundance of a keystone predator (Glaucidium passerinum) in fragmented landscapes. We concluded that the CCTO offered the most probable explanation for variation in the composition of the Parus guild across landscapes. PMID:17389222

Composition of an avian guild in spatially structured habitats supports a competition-colonization trade-off.

PubMed

Rodríguez, Alejandro; Jansson, Gunnar; Andrén, Henrik

2007-06-07

Assuming better colonization abilities of inferior competitors, the competition-colonization trade-off (CCTO) is one of the hypotheses that explains spatial variation of species composition in fragmented habitats. Whereas this mechanism may structure some plant and insect communities, ecologists have failed to document its operation in other natural systems, and its generality has been questioned. We combined fieldwork and published data to study the composition of a guild of passerines (Parus cristatus, Parus montanus, Parus ater and Regulus regulus) inhabiting 10 landscapes that differed in the amount of forest habitat. The species were ordered in a stable, well-defined competitive hierarchy, and the dispersal ability of each species was inversely correlated with its position in this hierarchy. In functionally continuous landscapes, superior competitors occupied most fragments and all guild members commonly occurred. The relative incidences of superior and inferior competitors were reversed, and differences amplified, in landscapes where patches were physically (distance) or functionally (matrix hardness) isolated. We found little support for two competing hypotheses, namely reduced habitat quality in isolated patches and lower abundance of a keystone predator (Glaucidium passerinum) in fragmented landscapes. We concluded that the CCTO offered the most probable explanation for variation in the composition of the Parus guild across landscapes.

Nutritional contributions of insects to primate diets: implications for primate evolution.

PubMed

Rothman, Jessica M; Raubenheimer, David; Bryer, Margaret A H; Takahashi, Maressa; Gilbert, Christopher C

2014-06-01

Insects and other invertebrates form a portion of many living and extinct primate diets. We review the nutritional profiles of insects in comparison with other dietary items, and discuss insect nutrients in relation to the nutritional needs of living primates. We find that insects are incorporated into some primate diets as staple foods whereby they are the majority of food intake. They can also be incorporated as complements to other foods in the diet, providing protein in a diet otherwise dominated by gums and/or fruits, or be incorporated as supplements to likely provide an essential nutrient that is not available in the typical diet. During times when they are very abundant, such as in insect outbreaks, insects can serve as replacements to the usual foods eaten by primates. Nutritionally, insects are high in protein and fat compared with typical dietary items like fruit and vegetation. However, insects are small in size and for larger primates (>1 kg) it is usually nutritionally profitable only to consume insects when they are available in large quantities. In small quantities, they may serve to provide important vitamins and fatty acids typically unavailable in primate diets. In a brief analysis, we found that soft-bodied insects are higher in fat though similar in chitin and protein than hard-bodied insects. In the fossil record, primates can be defined as soft- or hard-bodied insect feeders based on dental morphology. The differences in the nutritional composition of insects may have implications for understanding early primate evolution and ecology. Copyright © 2014 Elsevier Ltd. All rights reserved.

Remote sensing of forest insect disturbances: Current state and future directions

NASA Astrophysics Data System (ADS)

Senf, Cornelius; Seidl, Rupert; Hostert, Patrick

2017-08-01

Insect disturbance are important agents of change in forest ecosystems around the globe, yet their spatial and temporal distribution and dynamics are not well understood. Remote sensing has gained much attention in mapping and understanding insect outbreak dynamics. Consequently, we here review the current literature on the remote sensing of insect disturbances. We suggest to group studies into three insect types: bark beetles, broadleaved defoliators, and coniferous defoliators. By so doing, we systematically compare the sensors and methods used for mapping insect disturbances within and across insect types. Results suggest that there are substantial differences between methods used for mapping bark beetles and defoliators, and between methods used for mapping broadleaved and coniferous defoliators. Following from this, we highlight approaches that are particularly suited for each insect type. Finally, we conclude by highlighting future research directions for remote sensing of insect disturbances. In particular, we suggest to: 1) Separate insect disturbances from other agents; 2) Extend the spatial and temporal domain of analysis; 3) Make use of dense time series; 4) Operationalize near-real time monitoring of insect disturbances; 5) Identify insect disturbances in the context of coupled human-natural systems; and 6) Improve reference data for assessing insect disturbances. Since the remote sensing of insect disturbances has gained much interest beyond the remote sensing community recently, the future developments identified here will help integrating remote sensing products into operational forest management. Furthermore, an improved spatiotemporal quantification of insect disturbances will support an inclusion of these processes into regional to global ecosystem models.

Remote sensing of forest insect disturbances: Current state and future directions.

PubMed

Senf, Cornelius; Seidl, Rupert; Hostert, Patrick

2017-08-01

Insect disturbance are important agents of change in forest ecosystems around the globe, yet their spatial and temporal distribution and dynamics are not well understood. Remote sensing has gained much attention in mapping and understanding insect outbreak dynamics. Consequently, we here review the current literature on the remote sensing of insect disturbances. We suggest to group studies into three insect types: bark beetles, broadleaved defoliators, and coniferous defoliators. By so doing, we systematically compare the sensors and methods used for mapping insect disturbances within and across insect types. Results suggest that there are substantial differences between methods used for mapping bark beetles and defoliators, and between methods used for mapping broadleaved and coniferous defoliators. Following from this, we highlight approaches that are particularly suited for each insect type. Finally, we conclude by highlighting future research directions for remote sensing of insect disturbances. In particular, we suggest to: 1) Separate insect disturbances from other agents; 2) Extend the spatial and temporal domain of analysis; 3) Make use of dense time series; 4) Operationalize near-real time monitoring of insect disturbances; 5) Identify insect disturbances in the context of coupled human-natural systems; and 6) Improve reference data for assessing insect disturbances. Since the remote sensing of insect disturbances has gained much interest beyond the remote sensing community recently, the future developments identified here will help integrating remote sensing products into operational forest management. Furthermore, an improved spatiotemporal quantification of insect disturbances will support an inclusion of these processes into regional to global ecosystem models.

Feedbacks between community assembly and habitat selection shape variation in local colonization

USGS Publications Warehouse

Kraus, J.M.; Vonesh, J.R.

2010-01-01

1. Non-consumptive effects of predators are increasingly recognized as important drivers of community assembly and structure. Specifically, habitat selection responses to top predators during colonization and oviposition can lead to large differences in aquatic community structure, composition and diversity. 2. These differences among communities due to predators may develop as communities assemble, potentially altering the relative quality of predator vs. predator-free habitats through time. If so, community assembly would be expected to modify the subsequent behavioural responses of colonists to habitats containing top predators. Here, we test this hypothesis by manipulating community assembly and the presence of fish in experimental ponds and measuring their independent and combined effects on patterns of colonization by insects and amphibians. 3. Assembly modified habitat selection of dytscid beetles and hylid frogs by decreasing or even reversing avoidance of pools containing blue-spotted sunfish (Enneacanthus gloriosus). However, not all habitat selection responses to fish depended on assembly history. Hydrophilid beetles and mosquitoes avoided fish while chironomids were attracted to fish pools, regardless of assembly history. 4. Our results show that community assembly causes taxa-dependent feedbacks that can modify avoidance of habitats containing a top predator. Thus, non-consumptive effects of a top predator on community structure change as communities assemble and effects of competitors and other predators combine with the direct effects of top predators to shape colonization. 5. This work reinforces the importance of habitat selection for community assembly in aquatic systems, while illustrating the range of factors that may influence colonization rates and resulting community structure. Directly manipulating communities both during colonization and post-colonization is critical for elucidating how sequential processes interact to shape communities.

Seasonal and annual variations in the pollination efficiency of a pollinator community of Dictamnus albus L.

PubMed

Fisogni, A; Rossi, M; Sgolastra, F; Bortolotti, L; Bogo, G; de Manincor, N; Quaranta, M; Galloni, M

2016-05-01

The interplay between insect and plant traits outlines the patterns of pollen transfer and the subsequent plant reproductive fitness. We studied the factors that affect the pollination efficiency of a pollinator community of Dictamnus albus L. by evaluating insect behaviour and morphological characteristics in relation to flowering phenology. In order to extrapolate the pollinator importance of single taxa and of the whole pollinator guild, we calculated an index distinguishing between potential (PPI) and realized (RPI) pollinator importance. Although the pollinator species spectrum appeared rather constant, we found high intra- and inter-annual variability of pollinator frequency and importance within the insect community. Flower visitation rate strictly depended on insect abundance and on the overlap between their flying period and flower blooming. All the pollinators visited flowers from the bottom to the top of the racemes, excluding intra-plant geitonogamous pollination, and most of them showed high pollen fidelity. Only medium large-sized bees could contact the upward bending stiles while feeding on nectar, highlighting a specialisation of the plant towards bigger pollinators. Moreover, we found evidence of functional specialisation, since all pollinators were restricted to a single taxonomic group (order: Hymenoptera; superfamily: Apoidea). Both the PPI and RPI indices indicate Habropoda tarsata as the most important pollinator of D. albus. Following hand cross-pollination experiments we revealed the presence of pollination limitation in 1 of the 3 years of field study. We discuss this result in relation to flowering abundance and to possible mismatches of phenological periods between plants and insects. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

Insect-Specific Virus Discovery: Significance for the Arbovirus Community

PubMed Central

Bolling, Bethany G.; Weaver, Scott C.; Tesh, Robert B.; Vasilakis, Nikos

2015-01-01

Arthropod-borne viruses (arboviruses), especially those transmitted by mosquitoes, are a significant cause of morbidity and mortality in humans and animals worldwide. Recent discoveries indicate that mosquitoes are naturally infected with a wide range of other viruses, many within taxa occupied by arboviruses that are considered insect-specific. Over the past ten years there has been a dramatic increase in the literature describing novel insect-specific virus detection in mosquitoes, which has provided new insights about viral diversity and evolution, including that of arboviruses. It has also raised questions about what effects the mosquito virome has on arbovirus transmission. Additionally, the discovery of these new viruses has generated interest in their potential use as biological control agents as well as novel vaccine platforms. The arbovirus community will benefit from the growing database of knowledge concerning these newly described viral endosymbionts, as their impacts will likely be far reaching. PMID:26378568

Environmental and habitat drivers of relative abundance for a suite of azteca-attacking Pseudacteon phorid flies.

PubMed

Reese, Katlynd M; Philpott, Stacy M

2012-10-01

Phoridae (Diptera) have widespread impacts on insect communities by limiting host ant behavior. However, phorid-ant interactions may vary with habitat or environmental conditions. Three Pseudacteon species parasitize Azteca instabilis Fr. Smith, a common ant in coffee agroecosystems, and limit A. instabilis foraging, indirectly benefiting other insects. However, little is known about how phorid abundance, behavior, and effects change with environmental conditions. In shaded coffee systems, coffee (Coffea arabica L.) grows under a range of shade conditions and management changes affect species interactions. For example, Pseudacteon spp. more strongly limit A. instabilis foraging in low-shade coffee habitats. We sampled relative abundance of three phorid species around A. instabilis nests in three coffee habitats varying in shade management during dry and wet seasons. We measured canopy cover, tree richness, tree density, leaf litter depth, and number of nearby trees with A. instabilis to determine whether these habitat factors correlate with phorid abundance. P. laciniosus Brown was the most abundant phorid in both seasons. Phorid relative abundance did not differ by habitat, but did differ by season. P. laciniosus accounted for a higher proportion of phorids in the wet season (91.4%) than in the dry season (78.9%), and P. planidorsalis Brown accounted for a larger percent in the dry season (21.1%) than in the wet season (7.3%). Phorid composition did not differ with habitat type, and none of the measured environmental variables correlated with changes in phorid composition. Thus, phorids in coffee agroecosystems respond to large seasonal differences, but not differences between coffee habitats.

Insects on flowers

PubMed Central

Wardhaugh, Carl W.; Stork, Nigel E.; Edwards, Will; Grimbacher, Peter S.

2013-01-01

Insect biodiversity peaks in tropical rainforest environments where a large but as yet unknown proportion of species are found in the canopy. While there has been a proliferation of insect biodiversity research undertaken in the rainforest canopy, most studies focus solely on insects that inhabit the foliage. In a recent paper, we examined the distribution of canopy insects across five microhabitats (mature leaves, new leaves, flowers, fruit and suspended dead wood) in an Australian tropical rainforest, showing that the density (per dry weight gram of microhabitat) of insects on flowers were ten to ten thousand times higher than on the leaves. Flowers also supported a much higher number of species than expected based on their contribution to total forest biomass. Elsewhere we show that most of these beetle species were specialized to flowers with little overlap in species composition between different canopy microhabitats. Here we expand our discussion of the implications of our results with respect to specialization and the generation of insect biodiversity in the rainforest canopy. Lastly, we identify future directions for research into the biodiversity and specialization of flower-visitors in complex tropical rainforests. PMID:23802039

Forensic entomology: applications and limitations.

PubMed

Amendt, J; Richards, C S; Campobasso, C P; Zehner, R; Hall, M J R

2011-12-01

Forensic entomology is the science of collecting and analysing insect evidence to aid in forensic investigations. Its main application is in the determination of the minimum time since death in cases of suspicious death, either by estimating the age of the oldest necrophagous insects that developed on the corpse, or by analysing the insect species composition on the corpse. In addition, toxicological and molecular examinations of these insects may help reveal the cause of death or even the identity of a victim, by associating a larva with its last meal, for example, in cases where insect evidence is left at a scene after human remains have been deliberately removed. Some fly species can develop not only on corpses but on living bodies too, causing myiasis. Analysis of larvae in such cases can demonstrate the period of neglect of humans or animals. Without the appropriate professional collection of insect evidence, an accurate and convincing presentation of such evidence in court will be hampered or even impossible. The present paper describes the principles and methods of forensic entomology and the optimal techniques for collecting insect evidence.

Insects and related arthropods associated with greenleaf manzanita in montane chaparral communities of northeastern California

Treesearch

Michael A. Valenti; George T. Ferrell; Alan A. Berryman

1997-01-01

Specimens representing 19 orders and 169 arthropod families (mostly insects) were collected from greenleaf manzanita brushfields in northeastern California and identified to species whenever possible. More than500 taxa below the family level were inventoried, and each listing includes relative frequency of encounter, life stages collected, and dominant role in the...

The role of gut bacteria in Schmallenberg virus transmission by Culicoides biting midges

USDA-ARS?s Scientific Manuscript database

When an arbo-virus enters a vector it will first enter the gut system of this insect before entering cells of the insect body. Once in the gut-system, arbo-viruses and gut microbiota can interact with each other. We wondered if different gut bacterial communities could influence virus infection of b...

[Advances of forensic entomology in China].

PubMed

Lan, Ling-mei; Liao, Zhi-gang; Chen, Yao-qing; Yao, Yue; Li, Jian-bo; Li, Mao-yang; Cai, Ji-feng

2006-12-01

Forensic entomology is a branch of forensic medicine, which applies studies of insects and arthropods to getting evidence for court and has an analogous advantage in the estimation of the postmortem interval (PMI) and other questions of forensic relevance. The paper expounds its definition and contents and reviews some progress of the studies in some aspects in China such as the constitution and succession of insect community on the different cadavers, the applications of morphological features of insects and the technology of analysis of deoxyribonucleic acid (DNA) in forensic entomology, and forensic entomological toxicology etc.

Disentangling Environmental and Anthropogenic Impacts on the Distribution of Unintentionally Introduced Invasive Alien Insects in Mainland China

PubMed Central

Zhao, Cai-Yun; Xu, Jing; Liu, Xiao-Yan

2017-01-01

Abstract Globalization increases the opportunities for unintentionally introduced invasive alien species, especially for insects, and most of these species could damage ecosystems and cause economic loss in China. In this study, we analyzed drivers of the distribution of unintentionally introduced invasive alien insects. Based on the number of unintentionally introduced invasive alien insects and their presence/absence records in each province in mainland China, regression trees were built to elucidate the roles of environmental and anthropogenic factors on the number distribution and similarity of species composition of these insects. Classification and regression trees indicated climatic suitability (the mean temperature in January) and human economic activity (sum of total freight) are primary drivers for the number distribution pattern of unintentionally introduced invasive alien insects at provincial scale, while only environmental factors (the mean January temperature, the annual precipitation and the areas of provinces) significantly affect the similarity of them based on the multivariate regression trees. PMID:28973576

Gut Bacterial Community of the Xylophagous Cockroaches Cryptocercus punctulatus and Parasphaeria boleiriana

PubMed Central

Berlanga, Mercedes; Llorens, Carlos; Comas, Jaume; Guerrero, Ricardo

2016-01-01

Cryptocercus punctulatus and Parasphaeria boleiriana are two distantly related xylophagous and subsocial cockroaches. Cryptocercus is related to termites. Xylophagous cockroaches and termites are excellent model organisms for studying the symbiotic relationship between the insect and their microbiota. In this study, high-throughput 454 pyrosequencing of 16S rRNA was used to investigate the diversity of metagenomic gut communities of C. punctulatus and P. boleiriana, and thereby to identify possible shifts in symbiont allegiances during cockroaches evolution. Our results revealed that the hindgut prokaryotic communities of both xylophagous cockroaches are dominated by members of four Bacteria phyla: Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria. Other identified phyla were Spirochaetes, Planctomycetes, candidatus Saccharibacteria (formerly TM7), and Acidobacteria, each of which represented 1–2% of the total population detected. Community similarity based on phylogenetic relatedness by unweighted UniFrac analyses indicated that the composition of the bacterial community in the two species was significantly different (P < 0.05). Phylogenetic analysis based on the characterized clusters of Bacteroidetes, Spirochaetes, and Deltaproteobacteria showed that many OTUs present in both cockroach species clustered with sequences previously described in termites and other cockroaches, but not with those from other animals or environments. These results suggest that, during their evolution, those cockroaches conserved several bacterial communities from the microbiota of a common ancestor. The ecological stability of those microbial communities may imply the important functional role for the survival of the host of providing nutrients in appropriate quantities and balance. PMID:27054320

Convergence in mycorrhizal fungal communities due to drought, plant competition, parasitism, and susceptibility to herbivory: consequences for fungi and host plants.

PubMed

Gehring, Catherine A; Mueller, Rebecca C; Haskins, Kristin E; Rubow, Tine K; Whitham, Thomas G

2014-01-01

Plants and mycorrhizal fungi influence each other's abundance, diversity, and distribution. How other biotic interactions affect the mycorrhizal symbiosis is less well understood. Likewise, we know little about the effects of climate change on the fungal component of the symbiosis or its function. We synthesized our long-term studies on the influence of plant parasites, insect herbivores, competing trees, and drought on the ectomycorrhizal fungal communities associated with a foundation tree species of the southwestern United States, pinyon pine (Pinus edulis), and described how these changes feed back to affect host plant performance. We found that drought and all three of the biotic interactions studied resulted in similar shifts in ectomycorrhizal fungal community composition, demonstrating a convergence of the community towards dominance by a few closely related fungal taxa. Ectomycorrhizal fungi responded similarly to each of these stressors resulting in a predictable trajectory of community disassembly, consistent with ecological theory. Although we predicted that the fungal communities associated with trees stressed by drought, herbivory, competition, and parasitism would be poor mutualists, we found the opposite pattern in field studies. Our results suggest that climate change and the increased importance of herbivores, competitors, and parasites that can be associated with it, may ultimately lead to reductions in ectomycorrhizal fungal diversity, but that the remaining fungal community may be beneficial to host trees under the current climate and the warmer, drier climate predicted for the future.

Climate warming and agricultural stressors interact to determine stream macroinvertebrate community dynamics.

PubMed

Piggott, Jeremy J; Townsend, Colin R; Matthaei, Christoph D

2015-05-01

Global climate change is likely to modify the ecological consequences of currently acting stressors, but potentially important interactions between climate warming and land-use related stressors remain largely unknown. Agriculture affects streams and rivers worldwide, including via nutrient enrichment and increased fine sediment input. We manipulated nutrients (simulating agricultural run-off) and deposited fine sediment (simulating agricultural erosion) (two levels each) and water temperature (eight levels, 0-6°C above ambient) simultaneously in 128 streamside mesocosms to determine the individual and combined effects of the three stressors on macroinvertebrate community dynamics (community composition and body size structure of benthic, drift and insect emergence assemblages). All three stressors had pervasive individual effects, but in combination often produced additive or antagonistic outcomes. Changes in benthic community composition showed a complex interplay among habitat quality (with or without sediment), resource availability (with or without nutrient enrichment) and the behavioural/physiological tendency to drift or emerge as temperature rose. The presence of sediment and raised temperature both resulted in a community of smaller organisms. Deposited fine sediment strongly increased the propensity to drift. Stressor effects were most prominent in the benthic assemblage, frequently reflected by opposite patterns in individuals quitting the benthos (in terms of their propensity to drift or emerge). Of particular importance is that community measures of stream health routinely used around the world (taxon richness, EPT richness and diversity) all showed complex three-way interactions, with either a consistently stronger temperature response or a reversal of its direction when one or both agricultural stressors were also in operation. The negative effects of added fine sediment, which were often stronger at raised temperatures, suggest that streams already impacted by high sediment loads may be further degraded under a warming climate. However, the degree to which this will occur may also depend on in-stream nutrient conditions. © 2015 John Wiley & Sons Ltd.

Chemical composition, insecticidal and insect repellent activity of Schinus molle L. leaf and fruit essential oils against Trogoderma granarium and Tribolium castaneum.

PubMed

Abdel-Sattar, Essam; Zaitoun, Ahmed A; Farag, Mohamed A; Gayed, Sabah H El; Harraz, Fathalla M H

2010-02-01

Fruit and leaf essential oils of Schinus molle showed insect repellent and insecticidal activity against Trogoderma granarium and Tribolium castaneum. In these oils, 65 components were identified by GC-MS analysis. Hydrocarbons dominated the oil composition with monoterpenes occurring in the largest amounts in fruits and leaves, 80.43 and 74.84%, respectively. p-Cymene was identified as a major component in both oils. The high yield and efficacy of S. molle essential oil against T. granarium and T. castaneum suggest that it may provide leads for active insecticidal agents.

Identification of the cuticular lipid composition of the Western Flower Thrips Frankliniella occidentalis.

PubMed

Gołebiowski, Marek; Maliński, Edmund; Nawrot, Jan; Szafranek, Janusz; Stepnowski, Piotr

2007-06-01

The Western Flower Thrips Frankliniella occidentalis effectively resists many insecticides, but it can be controlled by the use of bioinsecticides such as entomopathogenic fungi. The epicuticular chemistry of these insects is therefore of great interest, and accordingly, the cuticular lipid composition of F. occidentalis was analysed. It was found that the cuticular lipids of both the adult and larval stages of F. occidentalis consist of two groups of compounds--hydrocarbons and free fatty acids. The same hydrocarbon pattern was found in both adults and larvae, with the exception of n-hentriacontane, which was detected only in adult insects. The following homologous series were identified: n-alkanes from C-25 to C-29 (31) with the marked dominance of odd numbers of carbon atoms, 3-methylalkanes with 26 and 28 carbon atoms, and branched monomethylalkanes (branched at C-9, -11, -13 and -15) with 26, 28 and 30 carbon atoms. The chemical composition of the free fatty acids consists of two homologous series: saturated (C(14:0), C(16:0), C(18:0)) and unsaturated fatty acids (C(16:1) and C(18:1)). This analysis confirmed the lack of potential inhibitors of entomopathogenic fungi in the cuticular lipids of this insect species.

Temporal dynamics of the arthropod community in pear orchards intercropped with aromatic plants.

PubMed

Beizhou, Song; Jie, Zhang; Jinghui, Hu; Hongying, Wu; Yun, Kong; Yuncong, Yao

2011-09-01

Increasing attention has been paid to enhancing biological control through habitat management in agricultural systems for enhanced pest management. Pest management benefits can be realised by intercropping, which can increase natural enemy abundance and, in turn, reduce pest abundance. In this study, the composition and temporal dynamics of arthropod communities in pear orchards when intercropped with aromatic plants were investigated, and the effectiveness and applicability of aromatic plants as intercrops for enhancing insect control were assessed. When compared with natural grasses or clean tillage, intercropping significantly reduced pest abundance and increased the ratio of natural enemies to pests. Intercropping also shortened the occurrence duration and depressed the incidence peak in annual dynamics curves of the pest subcommunity and the arthropod community, mainly because of the repellent effects of aromatic plants. Equally important, intercropping significantly reduced the numbers of major pests, such as Psylla chinensis, Aphis citricola and Pseudococcus comstocki, while their incidence period was delayed to varying degrees, and the numbers of their dominant natural enemies (Coccinella septempunctata, Phytoseiulus persimilis and Chrysoperla sinica) increased. Intercropping with aromatic plants led to a considerable improvement in arthropod pest management by enhancing the activity of the beneficial arthropod community within the pear orchard ecosystem. Copyright © 2011 Society of Chemical Industry.

Insect sex determination: it all evolves around transformer.

PubMed

Verhulst, Eveline C; van de Zande, Louis; Beukeboom, Leo W

2010-08-01

Insects exhibit a variety of sex determining mechanisms including male or female heterogamety and haplodiploidy. The primary signal that starts sex determination is processed by a cascade of genes ending with the conserved switch doublesex that controls sexual differentiation. Transformer is the doublesex splicing regulator and has been found in all examined insects, indicating its ancestral function as a sex-determining gene. Despite this conserved function, the variation in transformer nucleotide sequence, amino acid composition and protein structure can accommodate a multitude of upstream sex determining signals. Transformer regulation of doublesex and its taxonomic distribution indicate that the doublesex-transformer axis is conserved among all insects and that transformer is the key gene around which variation in sex determining mechanisms has evolved.

Influence of Surface Properties and Impact Conditions on Adhesion of Insect Residues

NASA Technical Reports Server (NTRS)

Wohl, Christopher J.; Smith, Joseph G.; Connell, John W.; Siochi, Emilie J.; Doss, Jereme R.; Shanahan, Michelle H.; Penner, Ronald K.

2015-01-01

Insect residues can cause premature transition to turbulent flow on laminar flow airfoils. Engineered surfaces that mitigate the adhesion of insect residues provide, therefore, a route to more efficient aerodynamics and reduced fuel burn rates. Areal coverage and heights of residues depend not only on surface properties, but also on impact conditions. We report high speed photography of fruit fly impacts at different angles of inclination on a rigid aluminum surface, optical microscopy and profilometry, and contact angle goniometry to support the design of engineered surfaces. For the polyurethane and epoxy coatings studied, some of which exhibited superhydrophobicity, it was determined that impact angle and surface compositions play critical roles in the efficacy of these surfaces to reduce insect residue adhesion.

Effectiveness of Winkler Litter Extraction and Pitfall Traps in Sampling Ant Communities and Functional Groups in a Temperate Forest.

PubMed

Mahon, Michael B; Campbell, Kaitlin U; Crist, Thomas O

2017-06-01

Selection of proper sampling methods for measuring a community of interest is essential whether the study goals are to conduct a species inventory, environmental monitoring, or a manipulative experiment. Insect diversity studies often employ multiple collection methods at the expense of researcher time and funding. Ants (Formicidae) are widely used in environmental monitoring owing to their sensitivity to ecosystem changes. When sampling ant communities, two passive techniques are recommended in combination: pitfall traps and Winkler litter extraction. These recommendations are often based on studies from highly diverse tropical regions or when a species inventory is the goal. Studies in temperate regions often focus on measuring consistent community response along gradients of disturbance or among management regimes; therefore, multiple sampling methods may be unnecessary. We compared the effectiveness of pitfalls and Winkler litter extraction in an eastern temperate forest for measuring ant species richness, composition, and occurrence of ant functional groups in response to experimental manipulations of two key forest ecosystem drivers, white-tailed deer and an invasive shrub (Amur honeysuckle). We found no significant effect of sampling method on the outcome of the ecological experiment; however, we found differences between the two sampling methods in the resulting ant species richness and functional group occurrence. Litter samples approximated the overall combined species richness and composition, but pitfalls were better at sampling large-bodied (Camponotus) species. We conclude that employing both methods is essential only for species inventories or monitoring ants in the Cold-climate Specialists functional group. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Combining Taxonomic and Functional Approaches to Unravel the Spatial Distribution of an Amazonian Butterfly Community.

PubMed

Graça, Márlon B; Morais, José W; Franklin, Elizabeth; Pequeno, Pedro A C L; Souza, Jorge L P; Bueno, Anderson Saldanha

2016-04-01

This study investigated the spatial distribution of an Amazonian fruit-feeding butterfly assemblage by linking species taxonomic and functional approaches. We hypothesized that: 1) vegetation richness (i.e., resources) and abundance of insectivorous birds (i.e., predators) should drive changes in butterfly taxonomic composition, 2) larval diet breadth should decrease with increase of plant species richness, 3) small-sized adults should be favored by higher abundance of birds, and 4) communities with eyespot markings should be able to exploit areas with higher predation pressure. Fruit-feeding butterflies were sampled with bait traps and insect nets across 25 km(2) of an Amazonian ombrophilous forest in Brazil. We measured larval diet breadth, adult body size, and wing marking of all butterflies. Our results showed that plant species richness explained most of the variation in butterfly taxonomic turnover. Also, community average diet breadth decreased with increase of plant species richness, which supports our expectations. In contrast, community average body size increased with the abundance of birds, refuting our hypothesis. We detected no influence of environmental gradients on the occurrence of species with eyespot markings. The association between butterfly taxonomic and functional composition points to a mediator role of the functional traits in the environmental filtering of butterflies. The incorporation of the functional approach into the analyses allowed for the detection of relationships that were not observed using a strictly taxonomic perspective and provided an extra insight into comprehending the potential adaptive strategies of butterflies. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Composition of entomopathogenic fungus and method of production and application for insect control

USDA-ARS?s Scientific Manuscript database

Microsclerotia of entomopathogenic fungi including Metarhizium and Lecanicillium species are produced using various production methods such as liquid culture fermentation. These microsclerotia can be dried with various agronomic carriers to produce viable, microsclerotia-containing compositions with...

Responses of aquatic insects to Cu and Zn in stream microcosms: understanding differences between single species tests and field responses.

PubMed

Clements, William H; Cadmus, Pete; Brinkman, Stephen F

2013-07-02

Field surveys of metal-contaminated streams suggest that some aquatic insects, particularly mayflies (Ephemeroptera) and stoneflies (Plecoptera), are highly sensitive to metals. However, results of single species toxicity tests indicate these organisms are quite tolerant, with LC50 values often several orders of magnitude greater than those obtained using standard test organisms (e.g., cladocerans and fathead minnows). Reconciling these differences is a critical research need, particularly since water quality criteria for metals are based primarily on results of single species toxicity tests. In this research we provide evidence based on community-level microcosm experiments to support the hypothesis that some aquatic insects are highly sensitive to metals. We present results of three experiments that quantified effects of Cu and Zn, alone and in combination, on stream insect communities. EC50 values, defined as the metal concentration that reduced abundance of aquatic insects by 50%, were several orders of magnitude lower than previously published values obtained from single species tests. We hypothesize that the short duration of laboratory toxicity tests and the failure to evaluate effects of metals on sensitive early life stages are the primary factors responsible for unrealistically high LC50 values in the literature. We also observed that Cu alone was significantly more toxic to aquatic insects than the combination of Cu and Zn, despite the fact that exposure concentrations represented theoretically similar toxicity levels. Our results suggest that water quality criteria for Zn were protective of most aquatic insects, whereas Cu was highly toxic to some species at concentrations near water quality criteria. Because of the functional significance of aquatic insects in stream ecosystems and their well-established importance as indicators of water quality, reconciling differences between field and laboratory responses and understanding the mechanisms responsible for variation in sensitivity among metals and metal mixtures is of critical importance.

Untangling the primary drivers of pinyon monoterpene production and emissions under predicted drought

NASA Astrophysics Data System (ADS)

Trowbridge, A. M.; Adams, H. D.; Breshears, D. D.; Monson, R. K.

2012-04-01

Climate and insect herbivory have important consequences for plant function, atmospheric composition, and the functioning of ecosystems and ecological communities. Within the last decade, pinyon-juniper woodlands throughout the southwestern U.S. have suffered large-scale mortality, especially of pinyon pine, due to drought and associated insect outbreaks. While much research has focused on the primary metabolic mechanisms underlying pinyon's sensitivity to drought, there remains a gap in our knowledge concerning how the resulting shift in carbon allocation toward plant secondary compounds, particularly monoterpenes, affects atmospheric process and ecological interactions. Monoterpenes are the principal constituents of pinyon resin. Because of their large global emission rates and effect on atmospheric chemistry, particularly ozone creation, identifying controls over emissions and sensitivities to environmental change is critical for global emission models. Furthermore, monoterpenes are known to impact insect behavior and act as defense compounds against herbivores, contributing to insect population fluctuations either directly through toxicity, or indirectly by influencing parasitism susceptibility. Pinyon mortality events are thought to be exacerbated by their susceptibility to herbivores resulting from weakened secondary chemical defenses, but the impact of current and predicted drought on the chemical defense status of pinyons and subsequent atmospheric and ecological consequences remain unknown. A field study was developed to examine the impact of seasonality and climate, particularly drought, on pinyon pine physiology and chemistry in the context of tiger moth (Lophocampa ingens) herbivory in pinyon-juniper woodlands. We demonstrate the importance of geography and seasonality, particularly mid-summer drought and late summer monsoons, in driving physiology and monoterpene concentrations and emissions. Emission rates significantly decreased throughout the summer and increased with a release from drought stress. Pinyons with past herbivore damage emitted significantly higher levels of monoterepenes (P<0.05), suggesting an interactive effect between herbivory and drought. Furthermore, neither temperature nor foliar monoterpene concentrations predicted emission rates, a result most likely due to the composite physiological response to both drought and insect herbivory. To tease apart the primary drivers of monoterpene emissions under drought stress, we developed a manipulative study by transplanting pinyons into a desert environment and increasing mean annual temperature by ~4 °C. We then measured pinyon physiology and monoterpene composition and emissions under different water and temperature regimes. Similar to our previous study, we saw that monoterpene emissions decreased with water availability across our treatments (P<0.05), with a 60% decrease in emissions from well-watered to drought stressed trees. While monoterpene emission rates early in the growing season in the native habitat were correlated with foliar concentrations and temperature, they were more constrained by water availability in transplanted trees as the growing season progressed. A possible explanation for these results could be that, unlike temperate species, semi-arid trees are physiologically more sensitive to water availability; therefore, we determined specific drought stress level and water potential thresholds at which this decoupling of temperature-dependent monoterpene emissions occurs. These results have led to the development of hypotheses about the consequences of future shifts in monoterpene concentrations and emissions due to drought affecting herbivore species interactions, outbreaks, and atmospheric processes.

Resilience of Alaska's Boreal Forest to Climatic Change

NASA Technical Reports Server (NTRS)

Chapin, F. S., III; McGuire, A. D.; Ruess, R. W.; Hollingsworth, T. N.; Mack, M. C.; Johnstone, J. F.; Kasischke, E. S.; Euskirchen, E. S.; Jones, J. B.; Jorgenson, M. T.;

Resilience of Alaska’s boreal forest to climatic change

USGS Publications Warehouse

Chapin, F.S.; McGuire, A. David; Ruess, Roger W.; Hollingsworth, Teresa N.; Mack, M.C.; Johnstone, J.F.; Kasischke, E.S.; Euskirchen, E.S.; Jones, J.B.; Jorgenson, M.T.; Kielland, K.; Kofinas, G.; Turetsky, M.R.; Yarie, J.; Lloyd, A.H.; Taylor, D.L.

2010-01-01

This paper assesses the resilience of Alaska’s boreal forest system to rapid climatic change. Recent warming is associated with reduced growth of dominant tree species, plant disease and insect outbreaks, warming and thawing of permafrost, drying of lakes, increased wildfire extent, increased postfire recruitment of deciduous trees, and reduced safety of hunters traveling on river ice. These changes have modified key structural features, feedbacks, and interactions in the boreal forest, including reduced effects of upland permafrost on regional hydrology, expansion of boreal forest into tundra, and amplification of climate warming because of reduced albedo (shorter winter season) and carbon release from wildfires. Other temperature-sensitive processes for which no trends have been detected include composition of plant and microbial communities, long-term landscape-scale change in carbon stocks, stream discharge, mammalian population dynamics, and river access and subsistence opportunities for rural indigenous communities. Projections of continued warming suggest that Alaska’s boreal forest will undergo significant functional and structural changes within the next few decades that are unprecedented in the last 6000 years. The impact of these social–ecological changes will depend in part on the extent of landscape reorganization between uplands and lowlands and on policies regulating subsistence opportunities for rural communities.

Functional symbiosis and communication in microbial ecosystems. The case of wood-eating termites and cockroaches.

PubMed

Berlanga, Mercedes

2015-09-01

Animal hosts typically have strong specificity for microbial symbionts and their functions. The symbiotic relationships have enhanced the limited metabolic networks of most eukaryotes by contributing several prokaryotic metabolic capabilities, such as methanogenesis, chemolithoautotrophy, nitrogen assimilation, etc. This review will examine the characteristics that determine bacterial "fidelity" to certain groups of animals (e.g., xylophagous insects, such as termites and cockroaches) over generations and throughout evolution. The hindgut bacteria of wood-feeding termites and cockroaches belong to several phyla, including Proteobacteria, especially Deltaproteobacteria, Bacteroidetes, Firmicutes, Actinomycetes, Spirochetes, Verrucomicrobia, and Actinobacteria, as detected by 16S rRNA. Termites effectively feed on many types of lignocelluloses assisted by their gut microbial symbionts. Although the community structures differ between the hosts (termites and cockroaches), with changes in the relative abundances of particular bacterial taxa, the composition of the bacterial community could reflect at least in part the host evolution in that the microbiota may derive from the microbiota of a common ancestor. Therefore, factors other than host phylogeny, such as diet could have had strong influence in shaping the bacterial community structure. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

Phytochemical diversity drives plant–insect community diversity

PubMed Central

Richards, Lora A.; Dyer, Lee A.; Forister, Matthew L.; Smilanich, Angela M.; Dodson, Craig D.; Leonard, Michael D.; Jeffrey, Christopher S.

2015-01-01

What are the ecological causes and consequences of variation in phytochemical diversity within and between plant taxa? Despite decades of natural products discovery by organic chemists and research by chemical ecologists, our understanding of phytochemically mediated ecological processes in natural communities has been restricted to studies of either broad classes of compounds or a small number of well-characterized molecules. Until now, no studies have assessed the ecological causes or consequences of rigorously quantified phytochemical diversity across taxa in natural systems. Consequently, hypotheses that attempt to explain variation in phytochemical diversity among plants remain largely untested. We use spectral data from crude plant extracts to characterize phytochemical diversity in a suite of co-occurring plants in the tropical genus Piper (Piperaceae). In combination with 20 years of data focused on Piper-associated insects, we find that phytochemical diversity has a direct and positive effect on the diversity of herbivores but also reduces overall herbivore damage. Elevated chemical diversity is associated with more specialized assemblages of herbivores, and the cascading positive effect of phytochemistry on herbivore enemies is stronger as herbivore diet breadth narrows. These results are consistent with traditional hypotheses that predict positive associations between plant chemical diversity, insect herbivore diversity, and trophic specialization. It is clear from these results that high phytochemical diversity not only enhances the diversity of plant-associated insects but also contributes to the ecological predominance of specialized insect herbivores. PMID:26283384

Trophic Interactions Between Insects and Stream-Associated Amphibians in Steep, Cobble-Bottom Streams of the Pacific Coast of North America

PubMed Central

Atwood, Trisha; Richardson, John S.

2012-01-01

Two native, stream-associated amphibians are found in coastal streams of the west coast of North America, the tailed frog and the coastal giant salamander, and each interacts with stream insects in contrasting ways. For tailed frogs, their tadpoles are the primary life stage found in steep streams and they consume biofilm from rock surfaces, which can have trophic and non-trophic effects on stream insects. By virtue of their size the tadpoles are relatively insensitive to stream insect larvae, and tadpoles are capable of depleting biofilm levels directly (exploitative competition), and may also “bulldoze” insect larvae from the surfaces of stones (interference competition). Coastal giant salamander larvae, and sometimes adults, are found in small streams where they prey primarily on stream insects, as well as other small prey. This predator-prey interaction with stream insects does not appear to result in differences in the stream invertebrate community between streams with and without salamander larvae. These two examples illustrate the potential for trophic and non-trophic interactions between stream-associated amphibians and stream insects, and also highlights the need for further research in these systems. PMID:26466536

The lepidoptera as predictable communities of herbivores: a test of niche assembly using the moth communities of Morgan-Monroe State Forest

Treesearch

Keith S. Summerville; Michael R. Saunders; Jamie L. Lane

2013-01-01

The response of forest insect communities to disturbances such as timber harvest likely will depend on the underlying ecological assembly rules that affect community structure. Two competing hypotheses are niche assembly, which seeks to demonstrate significant species-environment correlations, and dispersal-assembly, which seeks to demonstrate spatial autocorrelation...

Growth performance and feed conversion efficiency of three edible mealworm species (Coleoptera: Tenebrionidae) on diets composed of organic by-products.

PubMed

van Broekhoven, Sarah; Oonincx, Dennis G A B; van Huis, Arnold; van Loon, Joop J A

2015-02-01

Insects receive increasing attention as an alternative protein-rich food source for humans. Producing edible insects on diets composed of organic by-products could increase sustainability. In addition, insect growth rate and body composition, and hence nutritional quality, can be altered by diet. Three edible mealworm species Tenebrio molitor L., Zophobas atratus Fab. and Alphitobius diaperinus Panzer were grown on diets composed of organic by-products originating from beer brewing, bread/cookie baking, potato processing and bioethanol production. Experimental diets differed with respect to protein and starch content. Larval growth and survival was monitored. Moreover, effects of dietary composition on feed conversion efficiency and mealworm crude protein and fatty acid profile were assessed. Diet affected mealworm development and feed conversion efficiency such that diets high in yeast-derived protein appear favourable, compared to diets used by commercial breeders, with respect to shortening larval development time, reducing mortality and increasing weight gain. Diet also affected the chemical composition of mealworms. Larval protein content was stable on diets that differed 2-3-fold in protein content, whereas dietary fat did have an effect on larval fat content and fatty acid profile. However, larval fatty acid profile did not necessarily follow the same trend as dietary fatty acid composition. Diets that allowed for fast larval growth and low mortality in this study led to a comparable or less favourable n6/n3 fatty acid ratio compared to control diets used by commercial breeders. In conclusion, the mealworm species used in this study can be grown successfully on diets composed of organic by-products. Diet composition did not influence larval protein content, but did alter larval fat composition to a certain extent. Copyright © 2015 Elsevier Ltd. All rights reserved.

Made for Each Other: Ascomycete Yeasts and Insects.

PubMed

Blackwell, Meredith

2017-06-01

Fungi and insects live together in the same habitats, and many species of both groups rely on each other for success. Insects, the most successful animals on Earth, cannot produce sterols, essential vitamins, and many enzymes; fungi, often yeast-like in growth form, make up for these deficits. Fungi, however, require constantly replenished substrates because they consume the previous ones, and insects, sometimes lured by volatile fungal compounds, carry fungi directly to a similar, but fresh, habitat. Yeasts associated with insects include Ascomycota (Saccharomycotina, Pezizomycotina) and a few Basidiomycota. Beetles, homopterans, and flies are important associates of fungi, and in turn the insects carry yeasts in pits, specialized external pouches, and modified gut pockets. Some yeasts undergo sexual reproduction within the insect gut, where the genetic diversity of the population is increased, while others, well suited to their stable environment, may never mate. The range of interactions extends from dispersal of yeasts on the surface of insects (e.g., cactus- Drosophila -yeast and ephemeral flower communities, ambrosia beetles, yeasts with holdfasts) to extremely specialized associations of organisms that can no longer exist independently, as in the case of yeast-like symbionts of planthoppers. In a few cases yeast-like fungus-insect associations threaten butterflies and other species with extinction. Technical advances improve discovery and identification of the fungi but also inform our understanding of the evolution of yeast-insect symbioses, although there is much more to learn.

Effects of CO{sub 2} and NO{sub 3}{sup -} availability on deciduous trees: Phytochemistry and insect performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kinney, K.K.; Lindroth, R.L.; Jung, S.M.

1997-01-01

Increasing concentrations of atmospheric CO{sub 2} will interact with other environmental factors to influence the physiology and ecology of trees. This research evaluated how plant phytochemical responses to enriched atmospheric CO{sub 2} are affected by the availability of soil nitrate (NO{sub 3}{sup -}) and how these chemical changes alter performance of a tree-feeding folivore. Seedlings of three deciduous tree species were grown in ambient or elevated CO{sub 2} in combination with low or high soil NO{sub 3}{sup -} availability. Lymantria dispar larvae were reared on foliage (aspen and maple). Concentrations of nitrogen and soluble protein decreased, whereas concentrations of starch,more » condensed tannins, and ellagitannins increased, in response to elevated CO{sub 2} and/or low NO{sub 3}{sup -}. Responses of simple carbohydrates and phenolic glycosides were variable absolute (net) changes in foliar C:N ratios were greatest for aspen and least for oak, whereas relative changes were greatest for maple and least for aspen. Elevated CO{sub 2} treatments had little effect on gypsy moth development time, growth rate, or larval mass. Larvae reared on aspen foliage grown under elevated CO{sub 2} exhibited increased consumption but decreased conversion efficiencies. Gypsy moth responses to NO{sub 3}{sup -} were strongly host specific. The magnitude of insect response elicited by resource-mediated shifts in host chemistry will depend on how levels of compounds with specific importance to insect fitness are affected. Relatively few true interactions occured between carbon and nitrogen availability and insect performance. Tree species frequently interacted with CO{sub 2} and/or NO{sub 3}{sup -} availability to affect both parameters. The effects of elevated atmospheric CO{sub 2} on terrestrial plant communities will depend on species composition and soil nutrient availability. 54 refs., 9 figs., 4 tabs.« less

The potential use of bacterial community succession in forensics as described by high throughput metagenomic sequencing

USDA-ARS?s Scientific Manuscript database

Decomposition studies primarily focus on the gross observable data that can be seen with the naked eye, such as insects or vertebrate scavengers, with little regard for what might be occurring at the microorganism community level. Here we document the 'necrobiome' or the community of species associ...

Effects of Insect Protein Supplementation during Resistance Training on Changes in Muscle Mass and Strength in Young Men.

PubMed

Vangsoe, Mathias T; Joergensen, Malte S; Heckmann, Lars-Henrik L; Hansen, Mette

2018-03-10

During prolonged resistance training, protein supplementation is known to promote morphological changes; however, no previous training studies have tested the effect of insect protein isolate in a human trial. The aim of this study was to investigate the potential effect of insect protein as a dietary supplement to increase muscle hypertrophy and strength gains during prolonged resistance training in young men. Eighteen healthy young men performed resistance training four day/week for eight weeks. Subjects were block randomized into two groups consuming either an insect protein isolate or isocaloric carbohydrate supplementation within 1 h after training and pre-sleep on training days. Strength and body composition were measured before and after intervention to detect adaptions to the resistance training. Three-day weighed dietary records were completed before and during intervention. Fat- and bone- free mass (FBFM) improved significantly in both groups (Mean (95% confidence interval (CI))), control group (Con): (2.5 kg (1.5, 3.5) p < 0.01), protein group (Pro): (2.7 kg (1.6, 3.8) p < 0.01) from pre- to post-. Leg and bench press one repetition maximum (1 RM) improved by Con: (42.0 kg (32.0, 52.0) p < 0.01) and (13.8 kg (10.3, 17.2) p < 0.01), Pro: (36.6 kg (27.3, 45.8) p < 0.01) and (8.1 kg (4.5, 11.8) p < 0.01), respectively. No significant differences in body composition and muscle strength improvements were found between groups. In young healthy men, insect protein supplementation did not improve adaptations to eight weeks of resistance training in comparison to carbohydrate supplementation. A high habitual protein intake in both Con and Pro may partly explain our observation of no superior effect of insect protein supplementation.

Effects of Insect Protein Supplementation during Resistance Training on Changes in Muscle Mass and Strength in Young Men

PubMed Central

Vangsoe, Mathias T.; Joergensen, Malte S.

2018-01-01

During prolonged resistance training, protein supplementation is known to promote morphological changes; however, no previous training studies have tested the effect of insect protein isolate in a human trial. The aim of this study was to investigate the potential effect of insect protein as a dietary supplement to increase muscle hypertrophy and strength gains during prolonged resistance training in young men. Eighteen healthy young men performed resistance training four day/week for eight weeks. Subjects were block randomized into two groups consuming either an insect protein isolate or isocaloric carbohydrate supplementation within 1 h after training and pre-sleep on training days. Strength and body composition were measured before and after intervention to detect adaptions to the resistance training. Three-day weighed dietary records were completed before and during intervention. Fat- and bone- free mass (FBFM) improved significantly in both groups (Mean (95% confidence interval (CI))), control group (Con): (2.5 kg (1.5, 3.5) p < 0.01), protein group (Pro): (2.7 kg (1.6, 3.8) p < 0.01) from pre- to post- leg and bench press one repetition maximum (1 RM) improved by Con: (42.0 kg (32.0, 52.0) p < 0.01) and (13.8 kg (10.3, 17.2) p < 0.01), Pro: (36.6 kg (27.3, 45.8) p < 0.01) and (8.1 kg (4.5, 11.8) p < 0.01), respectively. No significant differences in body composition and muscle strength improvements were found between groups. In young healthy men, insect protein supplementation did not improve adaptations to eight weeks of resistance training in comparison to carbohydrate supplementation. A high habitual protein intake in both Con and Pro may partly explain our observation of no superior effect of insect protein supplementation. PMID:29534456

A comparative analysis reveals weak relationships between ecological factors and beta diversity of stream insect metacommunities at two spatial levels.

PubMed

Heino, Jani; Melo, Adriano S; Bini, Luis Mauricio; Altermatt, Florian; Al-Shami, Salman A; Angeler, David G; Bonada, Núria; Brand, Cecilia; Callisto, Marcos; Cottenie, Karl; Dangles, Olivier; Dudgeon, David; Encalada, Andrea; Göthe, Emma; Grönroos, Mira; Hamada, Neusa; Jacobsen, Dean; Landeiro, Victor L; Ligeiro, Raphael; Martins, Renato T; Miserendino, María Laura; Md Rawi, Che Salmah; Rodrigues, Marciel E; Roque, Fabio de Oliveira; Sandin, Leonard; Schmera, Denes; Sgarbi, Luciano F; Simaika, John P; Siqueira, Tadeu; Thompson, Ross M; Townsend, Colin R

2015-03-01

The hypotheses that beta diversity should increase with decreasing latitude and increase with spatial extent of a region have rarely been tested based on a comparative analysis of multiple datasets, and no such study has focused on stream insects. We first assessed how well variability in beta diversity of stream insect metacommunities is predicted by insect group, latitude, spatial extent, altitudinal range, and dataset properties across multiple drainage basins throughout the world. Second, we assessed the relative roles of environmental and spatial factors in driving variation in assemblage composition within each drainage basin. Our analyses were based on a dataset of 95 stream insect metacommunities from 31 drainage basins distributed around the world. We used dissimilarity-based indices to quantify beta diversity for each metacommunity and, subsequently, regressed beta diversity on insect group, latitude, spatial extent, altitudinal range, and dataset properties (e.g., number of sites and percentage of presences). Within each metacommunity, we used a combination of spatial eigenfunction analyses and partial redundancy analysis to partition variation in assemblage structure into environmental, shared, spatial, and unexplained fractions. We found that dataset properties were more important predictors of beta diversity than ecological and geographical factors across multiple drainage basins. In the within-basin analyses, environmental and spatial variables were generally poor predictors of variation in assemblage composition. Our results revealed deviation from general biodiversity patterns because beta diversity did not show the expected decreasing trend with latitude. Our results also call for reconsideration of just how predictable stream assemblages are along ecological gradients, with implications for environmental assessment and conservation decisions. Our findings may also be applicable to other dynamic systems where predictability is low.

Thermographic analysis of waveguide-irradiated insect pupae

NASA Astrophysics Data System (ADS)

Olsen, Richard G.; Hammer, Wayne C.

1982-01-01

Pupae of the insect Tenebrio molitor L. were thermographically imaged during waveguide irradiation through longitudinal slots. T. molitor pupae have been subjects of microwave-induced teratology for a number of years, but until now the smallness of the insect has prevented detailed dosimetry. High-resolution thermographic imaging equipment was used to obtain the magnitude and spatial distribution of absorbed microwave energy at three frequencies, 1.3, 5.95, and 10 GHz. The detail of the thermal images obtained is sufficient to show the differential heating of structures as small as a single insect leg. Results show that the electrical properties of the head, thorax, and abdomen are sufficiently different to seriously impair the usefulness of any theoretical dosimetric model of homogeneous composition. Some general features of correlation with a slab model in waveguide are given.

Bed bug dermatitis, description of two cases in Rio de Janeiro, Brazil.

PubMed

Bernardes Filho, Fred; Quaresma, Maria Victória; Avelleira, João Carlos Regazzi; Azulay, David Rubem; Azulay-Abulafia, Luna; Bastos, Amanda Queiroz; Gonçalves, Teresa Cristina Monte

2015-01-01

Bed bugs are hematophagous insects which due to their morphological and biological characteristics are able to easily adapt themselves to human households. The authors describe two cases of dermatitis caused by bed bug bites in the city of Rio de Janeiro, Brazil. Patients presented linear lesions in the usual "breakfast, lunch and dinner" arrangement, suggesting this diagnosis. A visit to their dwellings showed infestation of insects identified as Cimex hemipterus. The knowledge of these insects by the dermatological community will contribute to an accurate diagnosis as well as subsidize the dissemination of information aiming for prevention.

Bed bug dermatitis, description of two cases in Rio de Janeiro, Brazil*

PubMed Central

Bernardes, Fred; Quaresma, Maria Victória; Avelleira, João Carlos Regazzi; Azulay, David Rubem; Azulay-Abulafia, Luna; Bastos, Amanda Queiroz; Gonçalves, Teresa Cristina Monte

2015-01-01

Bed bugs are hematophagous insects which due to their morphological and biological characteristics are able to easily adapt themselves to human households. The authors describe two cases of dermatitis caused by bed bug bites in the city of Rio de Janeiro, Brazil. Patients presented linear lesions in the usual "breakfast, lunch and dinner" arrangement, suggesting this diagnosis. A visit to their dwellings showed infestation of insects identified as Cimex hemipterus. The knowledge of these insects by the dermatological community will contribute to an accurate diagnosis as well as subsidize the dissemination of information aiming for prevention. PMID:25830996

Social insect genomes exhibit dramatic evolution in gene composition and regulation while preserving regulatory features linked to sociality

PubMed Central

Simola, Daniel F.; Wissler, Lothar; Donahue, Greg; Waterhouse, Robert M.; Helmkampf, Martin; Roux, Julien; Nygaard, Sanne; Glastad, Karl M.; Hagen, Darren E.; Viljakainen, Lumi; Reese, Justin T.; Hunt, Brendan G.; Graur, Dan; Elhaik, Eran; Kriventseva, Evgenia V.; Wen, Jiayu; Parker, Brian J.; Cash, Elizabeth; Privman, Eyal; Childers, Christopher P.; Muñoz-Torres, Monica C.; Boomsma, Jacobus J.; Bornberg-Bauer, Erich; Currie, Cameron R.; Elsik, Christine G.; Suen, Garret; Goodisman, Michael A.D.; Keller, Laurent; Liebig, Jürgen; Rawls, Alan; Reinberg, Danny; Smith, Chris D.; Smith, Chris R.; Tsutsui, Neil; Wurm, Yannick; Zdobnov, Evgeny M.; Berger, Shelley L.; Gadau, Jürgen

2013-01-01

Genomes of eusocial insects code for dramatic examples of phenotypic plasticity and social organization. We compared the genomes of seven ants, the honeybee, and various solitary insects to examine whether eusocial lineages share distinct features of genomic organization. Each ant lineage contains ∼4000 novel genes, but only 64 of these genes are conserved among all seven ants. Many gene families have been expanded in ants, notably those involved in chemical communication (e.g., desaturases and odorant receptors). Alignment of the ant genomes revealed reduced purifying selection compared with Drosophila without significantly reduced synteny. Correspondingly, ant genomes exhibit dramatic divergence of noncoding regulatory elements; however, extant conserved regions are enriched for novel noncoding RNAs and transcription factor–binding sites. Comparison of orthologous gene promoters between eusocial and solitary species revealed significant regulatory evolution in both cis (e.g., Creb) and trans (e.g., fork head) for nearly 2000 genes, many of which exhibit phenotypic plasticity. Our results emphasize that genomic changes can occur remarkably fast in ants, because two recently diverged leaf-cutter ant species exhibit faster accumulation of species-specific genes and greater divergence in regulatory elements compared with other ants or Drosophila. Thus, while the “socio-genomes” of ants and the honeybee are broadly characterized by a pervasive pattern of divergence in gene composition and regulation, they preserve lineage-specific regulatory features linked to eusociality. We propose that changes in gene regulation played a key role in the origins of insect eusociality, whereas changes in gene composition were more relevant for lineage-specific eusocial adaptations. PMID:23636946

Are the metabolomic responses to folivory of closely related plant species linked to macroevolutionary and plant-folivore coevolutionary processes?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rivas-Ubach, Albert; Hódar, José A.; Sardans, Jordi

The debate whether the coevolution of plants and insects or macroevolutionary processes (phylogeny) is the main driver determining the arsenal of molecular defensive compounds of plants remains unresolved. Attacks by herbivorous insects affect not only the composition of defensive compounds in plants but the entire metabolome (the set of molecular metabolites), including defensive compounds. Metabolomes are the final products of genotypes and are directly affected by macroevolutionary processes, so closely related species should have similar metabolomic compositions and may respond in similar ways to attacks by folivores. We analyzed the elemental compositions and metabolomes of needles from Pinus pinaster, P.more » nigra and P. sylvestris to determine if these closely related Pinus species with different coevolutionary histories with the caterpillars of the processionary moth respond similarly to attacks by this lepidopteran. All pines had different metabolomes and metabolic responses to herbivorous attack. The metabolomic variation among the pine species and the responses to folivory reflected their macroevolutionary relationships, with P. pinaster having the most divergent metabolome. The concentrations of phenolic metabolites were generally not higher in the attacked trees, which had lower concentrations of terpenes, suggesting that herbivores avoid individuals with high concentrations of terpenes. Our results suggest that macroevolutionary history plays important roles in the metabolomic responses of these pine species to folivory, but plant-insect coevolution probably constrains those responses. Combinations of different evolutionary factors and trade-offs are likely responsible for the different responses of each species to folivory, which is not necessarily exclusively linked to plant-insect coevolution.« less

Insects on flowers: The unexpectedly high biodiversity of flower-visiting beetles in a tropical rainforest canopy.

PubMed

Wardhaugh, Carl W; Stork, Nigel E; Edwards, Will; Grimbacher, Peter S

2013-01-01

Insect biodiversity peaks in tropical rainforest environments where a large but as yet unknown proportion of species are found in the canopy. While there has been a proliferation of insect biodiversity research undertaken in the rainforest canopy, most studies focus solely on insects that inhabit the foliage. In a recent paper, we examined the distribution of canopy insects across five microhabitats (mature leaves, new leaves, flowers, fruit and suspended dead wood) in an Australian tropical rainforest, showing that the density (per dry weight gram of microhabitat) of insects on flowers were ten to ten thousand times higher than on the leaves. Flowers also supported a much higher number of species than expected based on their contribution to total forest biomass. Elsewhere we show that most of these beetle species were specialized to flowers with little overlap in species composition between different canopy microhabitats. Here we expand our discussion of the implications of our results with respect to specialization and the generation of insect biodiversity in the rainforest canopy. Lastly, we identify future directions for research into the biodiversity and specialization of flower-visitors in complex tropical rainforests.

Traditional consumption of and rearing edible insects in Africa, Asia and Europe.

PubMed

Raheem, Dele; Carrascosa, Conrado; Oluwole, Oluwatoyin Bolanle; Nieuwland, Maaike; Saraiva, Ariana; Millán, Rafael; Raposo, António

2018-02-15

The traditional consumption of edible insects is common in one third of the world's population, mostly in Latin America, Africa and Asia. There are over one thousand identified species of insects eaten in some stage of their life cycle; and they play important roles in ensuring food security. The most common way to collect insects are from the wild, which is seasonal with limited availability and has an increasing demand resulting in a disruption to the ecosystem. There is a growing interest shown in rearing insects for commercial purposes, and an industrial scale production will be required to ensure steady supplies. Industrial production will need to take into account the living environment of insects, the nutritional composition of their feed and the overall efficiency of the production system. We provide a short overview on the consumption of and rearing insects in Africa, Asia and Europe. For Africa, a snapshot is given for Nigeria, Ghana, Central African Republic, Kenya and Uganda, while the following countries are reported for Asia: China, Japan, Lao People's Democratic Republic, Thailand and Vietnam. In addition, a list of insect species with the highest potential for food and feed in the European Union is provided with some reference to The Netherlands and Finland. The review concludes that there is need to better understand the rearing and farming procedures that will yield high quality edible insects in Africa, Asia and Europe.

Molecular Signatures of Nicotinoid-Pathogen Synergy in the Termite Gut

PubMed Central

Sen, Ruchira; Raychoudhury, Rhitoban; Cai, Yunpeng; Sun, Yijun; Lietze, Verena-Ulrike; Peterson, Brittany F.; Scharf, Michael E.; Boucias, Drion G.

2015-01-01

Previous studies in lower termites revealed unexpected synergies between nicotinoid insecticides and fungal entomopathogens. The present study investigated molecular mechanisms of nicotinoid-pathogen synergy in the lower termite Reticulitermes flavipes, using the nicotinoid, imidacloprid, in combination with fungal and bacterial entomopathogens. Particular focus was placed on metatranscriptome composition and microbial dynamics in the symbiont-rich termite gut, which houses diverse mixes of protists and bacteria. cDNA microarrays containing a mix of host and protist symbiont oligonucleotides were used to simultaneously assess termite and protist gene expression. Five treatments were compared that included single challenges with sublethal doses of fungi (Metharizium anisopliae), bacteria (Serratia marcescens) or imidacloprid, and dual challenges with fungi + imidacloprid or bacteria + imidacloprid. Our findings point towards protist dysbiosis and compromised social behavior, rather than suppression of stereotypical immune defense mechanisms, as the dominant factors underlying nicotinoid-pathogen synergy in termites. Also, greater impacts observed for the fungal pathogen than for the bacterial pathogen suggest that the rich bacterial symbiont community in the R. flavipes gut (>5000 species-level phylotypes) exists in an ecological balance that effectively excludes exogenous bacterial pathogens. These findings significantly advance our understanding of antimicrobial defenses in this important eusocial insect group, as well as provide novel insights into how nicotinoids can exert deleterious effects on social insect colonies. PMID:25837376

Studying the Effects of Hardwood Stand Modifications, Periodic Flooding, and Fire on Insect and Disease Communities in the Lower Mississippi River Ecosystem.

Treesearch

E.T. Nebeker; Theodor D. Leininger; J.S. Meadows

1998-01-01

Abstract - The relationship between stand modification and pest organisms (insects and diseases) has been noted in general with few specific studies to evaluate this relationship in the southern hardwoods. As a prerequisite to making the best improvement cut prescription, it is essential to have a perspective on thinning impacts that at present can...

Exoskeletons across the Pancrustacea: Comparative Morphology, Physiology, Biochemistry and Genetics.

PubMed

Roer, Robert; Abehsera, Shai; Sagi, Amir

2015-11-01

The exoskeletons of pancrustaceans, as typified by decapod crustaceans and insects, demonstrate a high degree of similarity with respect to histology, ultrastructure, function, and composition. The cuticular envelope in insects and the outer epicuticle in crustaceans both serve as the primary barrier to permeability of the exoskeleton, preventing loss of water and ions to the external medium. Prior to and following ecdysis, there is a sequence of expression and synthesis of different proteins by the cuticular epithelium for incorporation into the pre-exuvial and post-exuvial procuticle of insects and the exocuticle and endocuticle of crustaceans. Both exhibit regional differences in cuticular composition, e.g., the articular (intersegmental) membranes of insects and the arthrodial (joint) membranes of crustaceans. The primary difference between these cuticles is the ability to mineralize. Crustaceans' cuticles express a unique suite of proteins that provide for the nucleation and deposition of calcium carbonate. Orthologs of genes discussed in the present review were mined from a recently completed cuticular transcriptome of the crayfish, Cherax quadricarinatus, providing new insights into the nature of these proteins. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

Diversity of insect galls associated with coastal shrub vegetation in Rio de Janeiro, Brazil.

PubMed

Carvalho-Fernandes, Sheila P; Ascendino, Sharlene; Maia, Valéria C; Couri, Márcia S

2016-09-01

Surveys in the coastal sandy plains (restingas) of Rio de Janeiro have shown a great richness of galls. We investigated the galling insects in two preserved restingas areas of Rio de Janeiro state: Parque Estadual da Costa do Sol and Reserva Particular do Patrimônio Natural Fazenda Caruara. The collections were done each two months, from June 2011 to May 2012. We investigated 38 points during 45 minutes each per collection. The galls were taken to the laboratory for rearing the insects. A total number of 151 insect galls were found in 82 plant species distributed into 34 botanic families. Most of the galls occurred on leaves and the plant families with the highest richness of galls were Myrtaceae and Fabaceae. All the six insect orders with galling species were found in this survey, where Cecidomyiidae (Diptera) was the main galler group. Hymenoptera and Thysanoptera were found as parasitoids and inquilines in 29 galls. The richness of galls in the surveyed areas reveals the importance of restinga for the composition and diversity of gall-inducing insect fauna.

Disentangling Environmental and Anthropogenic Impacts on the Distribution of Unintentionally Introduced Invasive Alien Insects in Mainland China.

PubMed

Zhao, Cai-Yun; Li, Jun-Sheng; Xu, Jing; Liu, Xiao-Yan

2017-05-01

Globalization increases the opportunities for unintentionally introduced invasive alien species, especially for insects, and most of these species could damage ecosystems and cause economic loss in China. In this study, we analyzed drivers of the distribution of unintentionally introduced invasive alien insects. Based on the number of unintentionally introduced invasive alien insects and their presence/absence records in each province in mainland China, regression trees were built to elucidate the roles of environmental and anthropogenic factors on the number distribution and similarity of species composition of these insects. Classification and regression trees indicated climatic suitability (the mean temperature in January) and human economic activity (sum of total freight) are primary drivers for the number distribution pattern of unintentionally introduced invasive alien insects at provincial scale, while only environmental factors (the mean January temperature, the annual precipitation and the areas of provinces) significantly affect the similarity of them based on the multivariate regression trees. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Mechanical and structural characterization of the poroviscoelastic properties of natural and synthetic biocomposites

NASA Astrophysics Data System (ADS)

Hayot, Celine M.

Rubber-like insect cuticle is a light fibrous composite which exhibits great deformability and long range elasticity due to the presence of a large amount of the elastomeric protein resilin. The presence of resilin in specific locations in the insect body leads to the assumption that its main function is loss-free storage of energy. The composition of the cuticle reveals the presence of a resilin matrix in which chitin fibers are embedded. Nanoindentation testing was used to study the differences in the mechanical properties of the structure between genders and wing morphs of the sand field cricket, Gryllus firmus. The results provide insight into the structure-function relations associated with the properties of insect rubber-like cuticle from different morphs and genders. An understanding of this relationship is of great importance if synthetic bio-inspired loss-free composites are to be manufactured. Inspired by the rubber-like cuticle, a synthetic composite was made of the elastomeric protein elastin in which polycaprolactone fibers were embedded. Nanoindentation testing was used to investigate the differences in the mechanical properties of the synthetic rubber-like composite between materials crosslinked for different time periods (2, 4, and 6 hours). Furthermore, the characterization of the viscoelastic properties of the synthetic composite by nanoindentation reveals the composite crosslinked for 4 hours as an optimized strain energy storage material when employed at low frequency load cycles. Also, investigating the microstructure of the synthetic composite shows the presence of pores which, under deformation, are responsible for the generation of a simultaneous mechanical response to viscoelasticity which is known as poroelasticity. Thus in this dissertation a methodology is developed to decouple the viscoelastic and the poroelastic behavior by combining the nanoindentation technique with finite element simulations. With this approach, it is possible to quantify measurements of the poroviscoelastic properties of these rubber-like composites. Such techniques are expected to find broader applications for quantifying the influence of crosslinking density and environmental factors on the nanoscale mechanical properties of many other similar composites.

Galling Insects of the Brazilian Páramos: Species Richness and Composition Along High-Altitude Grasslands.

PubMed

Coelho, Marcel S; Carneiro, Marco Antônio Alves; Branco, Cristina A; Borges, Rafael Augusto Xavier; Fernandes, G Wilson

2017-12-08

In this work, we investigated the factors that determine the distribution of galling insects in high-altitude grasslands, locally called 'campos de altitude' of Mantiqueira Range and tested whether 1) richness of galling insects decreases with altitude, 2) galling insect richness increases with plant richness, 3) variation in galling insect diversity is predominantly a consequence of its β component, and 4) turnover is the main mechanism driving the beta diversity of both galling insects and plants. Galling insect richness did not exhibit a negative relationship with altitude, but it did increase with plant richness. The additive partition of regional richness (γ) into its local and beta components showed that local diversity (α) of galling insects and plants was relatively low in relation to regional diversity; the β component incorporated most of the regional diversity. This pattern was also found in the multiscale analysis of the additive partition for galling insects and plants. The beta diversity of galling insects and plants was driven predominantly by the process of turnover and minimally by nesting. The results reported here point out that the spatial distribution of galling insects is best explained by historical factors, such as the distribution of genera and species of key host plants, as well as their relation to habitat, than ecological effects such as hygrothermal stress - here represented by altitude. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

SPATIAL AGGREGATION IN A FOREST FLOOR INSECT DEPENDS ON SEASONAL CONGREGATION AND SCATTERING EFFECTS OF PREDATORS

EPA Science Inventory

Spatial aggregations arising from gregarious behavior are common in nature and have important implications for population dynamics, community stability, and conservation. However, the translation of aggregation behaviors into emergent properties of populations and communities de...

Cryptic biodiversity in streams - a comparison of macroinvertebrate communities based on morphological and DNA barcode identifications

EPA Science Inventory

Aquatic ecologists and entomologists have long known that species-level identifications were difficult, if not impossible, for many larval macroinvertebrates collected in streams. This study describes macroinvertebrate (primarily insect) communities from five coastal streams dist...

IPM of specialty crops and community gardens in north Florida

USDA-ARS?s Scientific Manuscript database

Insect pests post serious challenges to specialty crops (vegetables, fruits and nut crops) and community gardens in North Florida. The major vegetable pests include silverleaf whitefly, Bemisia argentifolii; the green peach aphid, Myzus persicae; southeastern green stinkbug, Nezara viridula; brown s...

Direct and indirect responses of tallgrass prairie butterflies to prescribed burning

USGS Publications Warehouse

Vogel, Jennifer A.; Koford, Rolf R.; Debinski, Diane M.

2010-01-01

Fire is an important tool in the conservation and restoration of tallgrass prairie ecosystems. We investigated how both the vegetation composition and butterfly community of tallgrass prairie remnants changed in relation to the elapsed time (in months) since prescribed fire. Butterfly richness and butterfly abundance were positively correlated with the time since burn. Habitat-specialist butterfly richness recovery time was greater than 70 months post-fire and habitat-specialist butterfly abundance recovery time was approximately 50 months post-fire. Thus, recovery times for butterfly populations after prescribed fires in our study were potentially longer than those previously reported. We used Path Analysis to evaluate the relative contributions of the direct effect of time since fire and the indirect effects of time since fire through changes in vegetation composition on butterfly abundance. Path models highlighted the importance of the indirect effects of fire on habitat features, such as increases in the cover of bare ground. Because fire return intervals on managed prairie remnants are often less than 5 years, information on recovery times for habitat-specialist insect species are of great importance. ?? 2010 Springer Science+Business Media B.V.

Assessment of knowledge and usage custom of traditional insect/mosquito repellent plants in Addis Zemen Town, South Gonder, North Western Ethiopia.

PubMed

Karunamoorthi, Kaliyaperumal; Mulelam, Adane; Wassie, Fentahun

2009-01-12

A cross-sectional descriptive study was carried out to assess the knowledge and usage custom of traditional insect/mosquitoes repellent plants among the inhabitants in Addis Zemen Town, Ethiopia. Stratified, systematic random sampling was used for selection of 393 households from the total of 5161 households. One adult from each household was interviewed. The ethnobotonical survey was carried out during the period February 2007 to March 2007. Data analysis was carried out using SPSS, version 9.0. Range and mean were analysed and appropriate tables, graphs and percentage were displayed. Level of significance also determined by using 95% of confidence intervals and p-value. Overall, 97.2% of the respondents had ample knowledge and usage custom concerning traditional insect/mosquito repellent plants. Application of smoke (91.55%) was one of the most commonly well-known methods amongst local community by burning the plant parts such as leaves, stems and roots. Leaves were used by 90.2% for the application smoke. Knowledge and usage custom of traditional insect/mosquito repellent plants had significantly associated with sex (p=0.013) and lower income of respondents (p=0.002). In spite of this, knowledge and usage custom had no significant association with age and educational status. Furthermore, the survey also indicated that most commonly known traditional insect/mosquito repellent plants were Woira*(1) (Olea europaea) 44%, Tinjut* (Ostostegia integrifolia) 39%, Neem* (Azadirachta indica) 14.1%, Wogert* (Silene macroserene) 1.4%, and Kebercho* (Echinops sp.) 1.1%. Indigenous traditional insect/mosquito repellent plants have been used by local hamlet since ancient times for various medicinal purposes. Besides, they are not toxic like existing modern synthetic chemical repellents. Therefore, the traditional use of repellent plants should be encouraged and promoted among the local community.

Shifting stream planform state decreases stream productivity yet increases riparian animal production.

PubMed

Venarsky, Michael P; Walters, David M; Hall, Robert O; Livers, Bridget; Wohl, Ellen

2018-05-01

In the Colorado Front Range (USA), disturbance history dictates stream planform. Undisturbed, old-growth streams have multiple channels and large amounts of wood and depositional habitat. Disturbed streams (wildfires and logging < 200 years ago) are single-channeled with mostly erosional habitat. We tested how these opposing stream states influenced organic matter, benthic macroinvertebrate secondary production, emerging aquatic insect flux, and riparian spider biomass. Organic matter and macroinvertebrate production did not differ among sites per unit area (m -2 ), but values were 2 ×-21 × higher in undisturbed reaches per unit of stream valley (m -1 valley) because total stream area was higher in undisturbed reaches. Insect emergence was similar among streams at the per unit area and per unit of stream valley. However, rescaling insect emergence to per meter of stream bank showed that the emerging insect biomass reaching the stream bank was lower in undisturbed sites because multi-channel reaches had 3 × more stream bank than single-channel reaches. Riparian spider biomass followed the same pattern as emerging aquatic insects, and we attribute this to bottom-up limitation caused by the multi-channeled undisturbed sites diluting prey quantity (emerging insects) reaching the stream bank (riparian spider habitat). These results show that historic landscape disturbances continue to influence stream and riparian communities in the Colorado Front Range. However, these legacy effects are only weakly influencing habitat-specific function and instead are primarily influencing stream-riparian community productivity by dictating both stream planform (total stream area, total stream bank length) and the proportional distribution of specific habitat types (pools vs riffles).

Shifting stream planform state decreases stream productivity yet increases riparian animal production

USGS Publications Warehouse

Venarsky, Michael P.; Walters, David M.; Hall, Robert O.; Livers, Bridget; Wohl, Ellen

2018-01-01

In the Colorado Front Range (USA), disturbance history dictates stream planform. Undisturbed, old-growth streams have multiple channels and large amounts of wood and depositional habitat. Disturbed streams (wildfires and logging < 200 years ago) are single-channeled with mostly erosional habitat. We tested how these opposing stream states influenced organic matter, benthic macroinvertebrate secondary production, emerging aquatic insect flux, and riparian spider biomass. Organic matter and macroinvertebrate production did not differ among sites per unit area (m−2), but values were 2 ×–21 × higher in undisturbed reaches per unit of stream valley (m−1 valley) because total stream area was higher in undisturbed reaches. Insect emergence was similar among streams at the per unit area and per unit of stream valley. However, rescaling insect emergence to per meter of stream bank showed that the emerging insect biomass reaching the stream bank was lower in undisturbed sites because multi-channel reaches had 3 × more stream bank than single-channel reaches. Riparian spider biomass followed the same pattern as emerging aquatic insects, and we attribute this to bottom-up limitation caused by the multi-channeled undisturbed sites diluting prey quantity (emerging insects) reaching the stream bank (riparian spider habitat). These results show that historic landscape disturbances continue to influence stream and riparian communities in the Colorado Front Range. However, these legacy effects are only weakly influencing habitat-specific function and instead are primarily influencing stream–riparian community productivity by dictating both stream planform (total stream area, total stream bank length) and the proportional distribution of specific habitat types (pools vs riffles).

Spatiotemporal diversity, structure and trophic guilds of insect assemblages in a semi-arid Sabkha ecosystem

PubMed Central

Menasria, Taha; Neffar, Souad; Chafaa, Smail; Bradai, Lyès; Chaibi, Rachid; Mekahlia, Mohamed Nacer; Bendjoudi, Djamel; Si Bachir, Abdelkrim

2015-01-01

The current study highlights some knowledge on the diversity and structure of insect communities and trophic groups living in Sabkha Djendli (semi-arid area of Northeastern Algeria). The entomofauna was monthly sampled from March to November 2006 using pitfall traps at eight sites located at the vicinity of the Sabkha. Structural and diversity parameters (species richness, Shannon index, evenness) were measured for both insect orders and trophic guilds. The canonical correspondence analysis (CCA) was applied to determine how vegetation parameters (species richness and cover) influence spatial and seasonal fluctuations of insect assemblages. The catches totalled 434 insect individuals classified into 75 species, 62 genera, 31 families and 7 orders, of which Coleoptera and Hymenoptera were the most abundant and constant over seasons and study stations. Spring and autumn presented the highest values of diversity parameters. Individual-based Chao-1 species richness estimator indicated 126 species for the total individuals captured in the Sabkha. Based on catch abundances, the structure of functional trophic groups was predators (37.3%), saprophages (26.7%), phytophages (20.5%), polyphages (10.8%), coprophages (4.6%); whereas in terms of numbers of species, they can be classified as phytophages (40%), predators (25.3%), polyphages (13.3%), saprophages (12%), coprophages (9.3%). The CCA demonstrated that phytophages and saprophages as well as Coleoptera and Orthoptera were positively correlated with the two parameters of vegetation, especially in spring and summer. While the abundance of coprophages was positively correlated with species richness of plants, polyphage density was positively associated with vegetation cover. The insect community showed high taxonomic and functional diversity that is closely related to diversity and vegetation cover in different stations of the wetland and seasons. PMID:25825682

Edible insects in China: Utilization and prospects.

PubMed

Feng, Ying; Chen, Xiao-Ming; Zhao, Min; He, Zhao; Sun, Long; Wang, Cheng-Ye; Ding, Wei-Feng

2018-04-01

The use of edible insects has a long history in China, where they have been consumed for more than 2000 years. In general, the level of acceptance is high for the consumption of insects in China. Many studies on edible insects have been conducted in the last 20 years, and the scope of the research includes the culture of entomophagy and the identification, nutritional value, farming and breeding of edible insects, in addition to food production and safety. Currently, 324 species of insects from 11 orders are documented that are either edible or associated with entomophagy in China, which include the common edible species, some less commonly consumed species and some medicinal insects. However, only approximately 10 to 20 types of insects are regularly consumed. The nutritional values for 174 species are available in China, including edible, feed and medicinal species. Although the nutritional values vary among species, all the insects examined contain protein, fat, vitamins and minerals at levels that meet human nutritional requirements. Edible insects were, and continue to be, consumed by different ethnic groups in many parts of China. People directly consume insects or food products made from insects. The processing of products from insect protein powder, oil and chitin, and the development of healthcare foods has been studied in China. People also consume insects indirectly by eating livestock that were fed insects, which may be a more acceptable pathway to use insects in human diets. Although limited, the data on the food safety of insects indicate that insects are safe for food or feed. Incidences of allergic reactions after consuming silkworm pupae, cicadas and crickets have been reported in China. Insect farming is a unique breeding industry in rural China and is a source of income for local people. Insects are reared and bred for human food, medicine and animal feed using two approaches in China: the insects are either fully domesticated and reared completely in captivity or are partially raised in captivity, and the insect habitat is manipulated to increase production. Depending on the type of relationship the insect has with humans, plants and the environment, different farming strategies are used. The social and scientific communities must work together to promote the use of insects as food and feed. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Baseline assessment of instream and riparian-zone biological resources on the Rio Grande in and near Big Bend National Park, Texas

USGS Publications Warehouse

Moring, James Bruce

2002-01-01

Five study sites, and a sampling reach within each site, were established on the Rio Grande in and near Big Bend National Park in 1999 to provide the National Park Service with data and information on the status of stream habitat, fish communities, and benthic macroinvertebrates. Differences in stream-habitat conditions and riparian vegetation reflect differences in surface geology among the five sampling reaches. In the most upstream reach, Colorado Canyon, where igneous rock predominates, streambed material is larger; and riparian vegetation is less diverse and not as dense as in the four other, mostly limestone reaches. Eighteen species of fish and a total of 474 individuals were collected among the five reaches; 348 of the 474 were minnows. The most fish species (15) were collected at the Santa Elena reach and the fewest species (9) at the Colorado Canyon and Johnson Ranch reaches. The fish community at Colorado Canyon was least like the fish communities at the four other reaches. Fish trophic structure reflected fish-community structure among the five reaches. Invertivores made up at least 60 percent of the trophic structure at all reaches except Colorado Canyon. Piscivores dominated the trophic structure at Colorado Canyon. At the four other reaches, piscivores were the smallest trophic group. Eighty percent of the benthic macroinvertebrate taxa collected were aquatic insects. Two species of blackfly were the most frequently collected invertebrate taxon. Net-spinning caddisflies were common at all reaches except Santa Elena. The aquatic-insect community at the Boquillas reach was least similar to the aquatic-insect community at the other reaches.

In Vivo Isotopic Labeling of Symbiotic Bacteria Involved in Cellulose Degradation and Nitrogen Recycling within the Gut of the Forest Cockchafer (Melolontha hippocastani).

PubMed

Alonso-Pernas, Pol; Bartram, Stefan; Arias-Cordero, Erika M; Novoselov, Alexey L; Halty-deLeon, Lorena; Shao, Yongqi; Boland, Wilhelm

2017-01-01

The guts of insects harbor symbiotic bacterial communities. However, due to their complexity, it is challenging to relate a specific symbiotic phylotype to its corresponding function. In the present study, we focused on the forest cockchafer ( Melolontha hippocastani ), a phytophagous insect with a dual life cycle, consisting of a root-feeding larval stage and a leaf-feeding adult stage. By combining in vivo stable isotope probing (SIP) with 13 C cellulose and 15 N urea as trophic links, with Illumina MiSeq (Illumina-SIP), we unraveled bacterial networks processing recalcitrant dietary components and recycling nitrogenous waste. The bacterial communities behind these processes change between larval and adult stages. In 13 C cellulose-fed insects, the bacterial families Lachnospiraceae and Enterobacteriaceae were isotopically labeled in larvae and adults, respectively. In 15 N urea-fed insects, the genera Burkholderia and Parabacteroides were isotopically labeled in larvae and adults, respectively. Additionally, the PICRUSt-predicted metagenome suggested a possible ability to degrade hemicellulose and to produce amino acids of, respectively, 13 C cellulose- and 15 N urea labeled bacteria. The incorporation of 15 N from ingested urea back into the insect body was confirmed, in larvae and adults, by isotope ratio mass spectrometry (IRMS). Besides highlighting key bacterial symbionts of the gut of M. hippocastani , this study provides example on how Illumina-SIP with multiple trophic links can be used to target microorganisms embracing different roles within an environment.

Size effects on insect hovering aerodynamics: an integrated computational study.

PubMed

Liu, H; Aono, H

2009-03-01

Hovering is a miracle of insects that is observed for all sizes of flying insects. Sizing effect in insect hovering on flapping-wing aerodynamics is of interest to both the micro-air-vehicle (MAV) community and also of importance to comparative morphologists. In this study, we present an integrated computational study of such size effects on insect hovering aerodynamics, which is performed using a biology-inspired dynamic flight simulator that integrates the modelling of realistic wing-body morphology, the modelling of flapping-wing and body kinematics and an in-house Navier-Stokes solver. Results of four typical insect hovering flights including a hawkmoth, a honeybee, a fruit fly and a thrips, over a wide range of Reynolds numbers from O(10(4)) to O(10(1)) are presented, which demonstrate the feasibility of the present integrated computational methods in quantitatively modelling and evaluating the unsteady aerodynamics in insect flapping flight. Our results based on realistically modelling of insect hovering therefore offer an integrated understanding of the near-field vortex dynamics, the far-field wake and downwash structures, and their correlation with the force production in terms of sizing and Reynolds number as well as wing kinematics. Our results not only give an integrated interpretation on the similarity and discrepancy of the near- and far-field vortex structures in insect hovering but also demonstrate that our methods can be an effective tool in the MAVs design.

Effects of fire retardant chemical and fire suppressant foam on shrub steppe vegetation in northern Nevada

USGS Publications Warehouse

Larson, Diane L.; Newton, Wesley E.; Anderson, Patrick J.; Stein, Steven J.

1999-01-01

The objectives of this study were to determine the effects of fire retardantchemical (Phos-Chek G75-F*) and fire suppressant foam (Silv-Ex) application,alone and in combination with fire, on Great Basin shrub steppe vegetation. Wemeasured growth, resprouting, flowering, and incidence of galling insects onChrysothamnus viscidiflorusandArtemisia tridentata. These characteristics were notaffected by any chemical treatment. We measured community characteristics,including species richness, evenness, and diversity, and number of stems ofwoody and herbaceous plants in riparian and upland plots. Of these characteristics, only species richness and number ofstems/m2 clearly responded to the chemicaltreatments, and the response was modified by fire. In general, speciesrichness declined, especially after Phos-Chek application. However, by the endof the growing season, species richness did not differ between treated andcontrol plots. Acanonical variate analysis suggested that burning had agreater influence on community composition than did the chemical treatments.In general, riparian areas showed more significant responses to the treatmentsthan did upland areas, and June applications produced greater changes inspecies richness and stem density than did July applications.

Seasonal Occurrence of Key Arthropod Pests and Beneficial Insects in Michigan High Tunnel and Field Grown Raspberries.

PubMed

Leach, Heather; Isaacs, Rufus

2018-06-06

Berry crops are increasingly produced in high tunnels, which provide growers with the opportunity to extend their production season. This is particularly beneficial for the northern region of the United States with short and unpredictable growing seasons and where rainfall limits fruit quality. However, little is known about the effect of high tunnels on the community of pests, natural enemies, or pollinators, especially in berry crops, and there are few reports of the insect community in raspberries in this region. We compared the abundance of these insects during two growing seasons in field-grown and tunnel-grown floricane and primocane producing raspberries through direct observation and trapping at five sites in southwestern and central Michigan. We found eight key pests, including spotted wing Drosophila, leafhoppers, and thrips, and seven key natural enemies including parasitoid wasps, spiders, and lacewings, that were common across all sites. Pest populations were up to 6.6 times higher in tunnels, and pests typical of greenhouse systems became more dominant in this environment. Natural enemies observed on plants under tunnels were also more abundant than in the field, but this trend was reversed for natural enemies trapped on yellow sticky cards. There was also a reduction of both honey bees and wild bees under the high tunnels, which was balanced by use of commercial bumble bees. These data not only provide much-needed information on the phenology of the insect community on raspberry plantings, they also highlight the entomological implications of protected raspberry culture.

Aphid-parasitoid community structure on genetically modified wheat.

PubMed

von Burg, Simone; van Veen, Frank J F; Álvarez-Alfageme, Fernando; Romeis, Jörg

2011-06-23

Since the introduction of genetically modified (GM) plants, one of the main concerns has been their potential effect on non-target insects. Many studies have looked at GM plant effects on single non-target herbivore species or on simple herbivore-natural enemy food chains. Agro-ecosystems, however, are characterized by numerous insect species which are involved in complex interactions, forming food webs. In this study, we looked at transgenic disease-resistant wheat (Triticum aestivum) and its effect on aphid-parasitoid food webs. We hypothesized that the GM of the wheat lines directly or indirectly affect aphids and that these effects cascade up to change the structure of the associated food webs. Over 2 years, we studied different experimental wheat lines under semi-field conditions. We constructed quantitative food webs to compare their properties on GM lines with the properties on corresponding non-transgenic controls. We found significant effects of the different wheat lines on insect community structure up to the fourth trophic level. However, the observed effects were inconsistent between study years and the variation between wheat varieties was as big as between GM plants and their controls. This suggests that the impact of our powdery mildew-resistant GM wheat plants on food web structure may be negligible and potential ecological effects on non-target insects limited.

Ubiquity of Insect-Derived Nitrogen Transfer to Plants by Endophytic Insect-Pathogenic Fungi: an Additional Branch of the Soil Nitrogen Cycle

PubMed Central

Behie, Scott W.

2014-01-01

The study of symbiotic nitrogen transfer in soil has largely focused on nitrogen-fixing bacteria. Vascular plants can lose a substantial amount of their nitrogen through insect herbivory. Previously, we showed that plants were able to reacquire nitrogen from insects through a partnership with the endophytic, insect-pathogenic fungus Metarhizium robertsii. That is, the endophytic capability and insect pathogenicity of M. robertsii are coupled so that the fungus acts as a conduit to provide insect-derived nitrogen to plant hosts. Here, we assess the ubiquity of this nitrogen transfer in five Metarhizium species representing those with broad (M. robertsii, M. brunneum, and M. guizhouense) and narrower insect host ranges (M. acridum and M. flavoviride), as well as the insect-pathogenic fungi Beauveria bassiana and Lecanicillium lecanii. Insects were injected with 15N-labeled nitrogen, and we tracked the incorporation of 15N into two dicots, haricot bean (Phaseolus vulgaris) and soybean (Glycine max), and two monocots, switchgrass (Panicum virgatum) and wheat (Triticum aestivum), in the presence of these fungi in soil microcosms. All Metarhizium species and B. bassiana but not L. lecanii showed the capacity to transfer nitrogen to plants, although to various degrees. Endophytic association by these fungi increased overall plant productivity. We also showed that in the field, where microbial competition is potentially high, M. robertsii was able to transfer insect-derived nitrogen to plants. Metarhizium spp. and B. bassiana have a worldwide distribution with high soil abundance and may play an important role in the ecological cycling of insect nitrogen back to plant communities. PMID:24334669

Changes in base composition bias of nuclear and mitochondrial genes in lice (Insecta: Psocodea).

PubMed

Yoshizawa, Kazunori; Johnson, Kevin P

2013-12-01

While it is well known that changes in the general processes of molecular evolution have occurred on a variety of timescales, the mechanisms underlying these changes are less well understood. Parasitic lice ("Phthiraptera") and their close relatives (infraorder Nanopsocetae of the insect order Psocodea) are a group of insects well known for their unusual features of molecular evolution. We examined changes in base composition across parasitic lice and bark lice. We identified substantial differences in percent GC content between the clade comprising parasitic lice plus closely related bark lice (=Nanopsocetae) versus all other bark lice. These changes occurred for both nuclear and mitochondrial protein coding and ribosomal RNA genes, often in the same direction. To evaluate whether correlations in base composition change also occurred within lineages, we used phylogenetically controlled comparisons, and in this case few significant correlations were identified. Examining more constrained sites (first/second codon positions and rRNA) revealed that, in comparison to the other bark lice, the GC content of parasitic lice and close relatives tended towards 50 % either up from less than 50 % GC or down from greater than 50 % GC. In contrast, less constrained sites (third codon positions) in both nuclear and mitochondrial genes showed less of a consistent change of base composition in parasitic lice and very close relatives. We conclude that relaxed selection on this group of insects is a potential explanation of the change in base composition for both mitochondrial and nuclear genes, which could lead to nucleotide frequencies closer to random expectation (i.e., 50 % GC) in the absence of any mutation bias. Evidence suggests this relaxed selection arose once in the non-parasitic common ancestor of Phthiraptera + Nanopsocetae and is not directly related to the evolution of the parasitism in lice.

An analytical model assessing the potential threat to natural habitats from insect resistance transgenes: continuous transgene input

PubMed Central

Kelly, Colleen K; Bowler, Michael; Breden, Felix

2006-01-01

The potential effects of ‘escape’ of genetically modified material (transgenes) into natural communities is a major concern in their use. These effects may be limited in the first instance by limiting the proportion of transgene-carrying plants in the natural community. We previously presented an analytical model of the ecological processes governing the relative abundance and persistence of insect resistance (IR) transgenes in a natural community. In that paper, we illustrated the case in which the transgene is input into the community in a single season using data from oilseed rape (OSR) and its known herbivore, Plutella macropennis. We found that the transgene is unlikely to have a great impact on the natural community. Here, we extend the model for repeated input of crop pollen carrying the transgene. We show the model output, again using OSR, for continuous input of the transgene over 10 years, the projected commercial lifetime of a transgene without associated undesirable agronomic effects. Our results do not change our original conclusion that the IR transgene need not have a large impact on the natural community and our suggestions for assessing and mitigating any threat still stand. PMID:17148386

Contrasting effects of invasive plants in plant-pollinator networks.

PubMed

Bartomeus, Ignasi; Vilà, Montserrat; Santamaría, Luís

2008-04-01

The structural organization of mutualism networks, typified by interspecific positive interactions, is important to maintain community diversity. However, there is little information available about the effect of introduced species on the structure of such networks. We compared uninvaded and invaded ecological communities, to examine how two species of invasive plants with large and showy flowers (Carpobrotus affine acinaciformis and Opuntia stricta) affect the structure of Mediterranean plant-pollinator networks. To attribute differences in pollination to the direct presence of the invasive species, areas were surveyed that contained similar native plant species cover, diversity and floral composition, with or without the invaders. Both invasive plant species received significantly more pollinator visits than any native species and invaders interacted strongly with pollinators. Overall, the pollinator community richness was similar in invaded and uninvaded plots, and only a few generalist pollinators visited invasive species exclusively. Invasive plants acted as pollination super generalists. The two species studied were visited by 43% and 31% of the total insect taxa in the community, respectively, suggesting they play a central role in the plant-pollinator networks. Carpobrotus and Opuntia had contrasting effects on pollinator visitation rates to native plants: Carpobrotus facilitated the visit of pollinators to native species, whereas Opuntia competed for pollinators with native species, increasing the nestedness of the plant-pollinator network. These results indicate that the introduction of a new species to a community can have important consequences for the structure of the plant-pollinator network.

Keystone nonconsumptive effects within a diverse predator community.

PubMed

Meadows, Amanda J; Owen, Jeb P; Snyder, William E

2017-12-01

The number of prey killed by diverse predator communities is determined by complementarity and interference among predators, and by traits of particular predator species. However, it is less clear how predators' nonconsumptive effects (NCEs) scale with increasing predator biodiversity. We examined NCEs exerted on Culex mosquitoes by a diverse community of aquatic predators. In the field, mosquito larvae co-occurred with differing densities and species compositions of mesopredator insects; top predator dragonfly naiads were present in roughly half of surveyed water bodies. We reproduced these predator community features in artificial ponds, exposing mosquito larvae to predator cues and measuring resulting effects on mosquito traits throughout development. Nonconsumptive effects of various combinations of mesopredator species reduced the survival of mosquito larvae to pupation, and reduced the size and longevity of adult mosquitoes that later emerged from the water. Intriguingly, adding single dragonfly naiads to ponds restored survivorship of larval mosquitoes to levels seen in the absence of predators, and further decreased adult mosquito longevity compared with mosquitoes emerging from mesopredator treatments. Behavioral observations revealed that mosquito larvae regularly deployed "diving" escape behavior in the presence of the mesopredators, but not when a dragonfly naiad was also present. This suggests that dragonflies may have relaxed NCEs of the mesopredators by causing mosquitoes to abandon energetically costly diving. Our study demonstrates that adding one individual of a functionally unique species can substantially alter community-wide NCEs of predators on prey. For pathogen vectors like mosquitoes, this could in turn influence disease dynamics.

Two gut community enterotypes recur in diverse bumblebee species

USDA-ARS?s Scientific Manuscript database

Pollinating insects are key to the evolutionary and ecological success of flowering plants and enable much of the diversity in the human diet. Gut microbial communities likely impact pollinators in diverse ways, from nutrition to defense against disease. Honeybees and bumblebees harbor a simple yet ...

Genetics, development and composition of the insect head--a beetle's view.

PubMed

Posnien, Nico; Schinko, Johannes B; Kittelmann, Sebastian; Bucher, Gregor

2010-11-01

Many questions regarding evolution and ontogeny of the insect head remain open. Likewise, the genetic basis of insect head development is poorly understood. Recently, the investigation of gene expression data and the analysis of patterning gene function have revived interest in insect head development. Here, we argue that the red flour beetle Tribolium castaneum is a well suited model organism to spearhead research with respect to the genetic control of insect head development. We review recent molecular data and discuss its bearing on early development and morphogenesis of the head. We present a novel hypothesis on the ontogenetic origin of insect head sutures and review recent insights into the question on the origin of the labrum. Further, we argue that the study of developmental genes may identify the elusive anterior non-segmental region and present some evidence in favor of its existence. With respect to the question of evolution of patterning we show that the head Anlagen of the fruit fly Drosophila melanogaster and Tribolium differ considerably and we review profound differences of their genetic regulation. Finally, we discuss which insect model species might help us to answer the open questions concerning the genetic regulation of head development and its evolution. Copyright © 2010 Elsevier Ltd. All rights reserved.

Revised age of deglaciation of Lake Emma based on new radiocarbon and macrofossil analyses

USGS Publications Warehouse

Elias, S.A.; Carrara, P.E.; Toolin, L.J.; Jull, A.J.T.

1991-01-01

Previous radiocarbon ages of detrital moss fragments in basal organic sediments of Lake Emma indicated that extensive deglaciation of the San Juan Mountains occurred prior to 14,900 yr B.P. (Carrara et al., 1984). Paleoecological analyses of insect and plant macrofossils from these basal sediments cast doubt on the reliability of the radiocarbon ages. Subsequent accelerator radiocarbon dates of insect fossils and wood fragments indicate an early Holocene age, rather than a late Pleistocene age, for the basal sediments of Lake Emma. These new radiocarbon ages suggest that by at least 10,000 yr B.P. deglaciation of the San Juan Mountains was complete. The insect and plant macrofossils from the basal organic sediments indicate a higher-than-present treeline during the early Holocene. The insect assemblages consisted of about 30% bark beetles, which contrasts markedly with the composition of insects from modern lake sediments and modern specimens collected in the Lake Emma cirque, in which bark beetles comprise only about 3% of the assemblages. In addition, in the fossil assemblages there were a number of flightless insect species (not subject to upslope transport by wind) indicative of coniferous forest environments. These insects were likewise absent in the modern assemblage. ?? 1991.

Different effects of variation in Xanthium strumarium L. (Compositae) on two insect seed predators.

PubMed

Hare, J Daniel; Futuyma, Douglas J

1978-01-01

To determine the relative importance of variation in several plant characters on susceptibility to herbivores, we examined patterns of seed predation by two monophagous insect species and patterns of variation in ten populations of the cocklebur, Xanthium strumarium. Multiple regression analysis disclosed that one seed predator was most influenced by plant chemical variation, the other was significantly influenced by both chemical and morphological variation, but variation in yet another character, general burr size, was most important in conferring resistance to both insects simultaneously. The plant populations differed most in this character. Although many of the plant characters were correlated with each other, those important in determining susceptibility to each insect species were uncorrelated and independent of those conferring resistance to both insects simultaneously.These results imply that ecological similar herbivores may be influenced by different aspects of plant variation, and that predictions of evolutionary responses of local plant populations to herbivory may require knowledge of the structure of local herbivore communities and the dynamics of their establishment.

Effects of fish density and river fertilization on algal standing stocks, invertebrates communities, and fish production in an Arctic River

USGS Publications Warehouse

Deegan, Linda A.; Peterson, B.J.; Golden, H.; McIvor, C.C.; Miller, M.C.

1997-01-01

This study examined the relative importance of bottom-up and top-down controls of an arctic stream food web by simultaneous manipulation of the top predator and nutrient availability. We created a two-step trophic system (algae to insects) by removal of the top predator (Arctic grayling, Thymallus arcticus) in fertilized and control stream reaches. Fish abundance was also increased 10 times to examine the effect of high fish density on stream ecosystem dynamics and fish. We measured the response of epilithic algae, benthic and drifting insects, and fish to nutrient enrichment and to changes in fish density. Insect grazers had little effect on algae and fish had little effect on insects. In both the control and fertilized reaches, fish growth, energy storage, and reproductive response of females declined with increased fish density. Fish growth and energy storage were more closely correlated with per capita insect availability than with per capita algal standing stock

The nutrient value of Imbrasia belina Lepidoptera: Saturnidae (madora).

PubMed

Onigbinde, A O; Adamolekun, B

1998-05-01

To determine the pattern of consumption of Imbrasia belina (madora) and other edible insects and also compare the nutrient values of madora larvae and two of its variants (Anaphe venata and Cirina forda) to those of some conventional sources of protein. University of Zimbabwe. 100 workers who admitted to a history of entomophagy. Popularity score of madora compared with those of other edible insects and approximate compositions of nutrients in the larvae compared with standard proteins. Most respondents (65%) were introduced to entomophagy by their parents. Termites were the most frequently consumed, followed by madora. More respondents ate insects because of their perceived nutritional value than because of their relative availability. There was no association of entomophagy with significant side effects. The protein, fat and mineral contents of the larvae were superior to those of beef and chicken. There were no major differences in the nutrient composition of the three Lepidoptera variants. The high nutrient value and low cost of these larvae make them an important protein supplement, especially for people in the low income group.

Investigation of Surface Enhanced Coherent Raman Scattering on Nano-patterned Insect Wings

NASA Astrophysics Data System (ADS)

Ujj, Laszlo; Lawhead, Carlos

2015-03-01

Many insect wings (cicadas, butterflies, mosquitos) poses nano-patterned surface structure. Characterization of surface morphology and chemical composition of insect wings is important to understand the extreme mechanical properties and the biophysical functionalities of the wings. We have measured the image of the membrane of a cicada's wing with the help of Scanning Electron Microscopy (SEM). The results confirm the existing periodic structure of the wing measured previously. In order to identify the chemical composition of the wing, we have deposited silver nanoparticles on it and applied Coherent anti-Stokes Raman Spectroscopy to measure the vibrational spectra of the molecules comprising the wing for the first time. The measured spectra are consistent with the original assumption that the wing membrane is composed of protein, wax, and chitin. The results of these studies can be used to measure other nano-patterned surfaces and to make artificial materials in the future. Authors grateful for financial support from the Department of Physics of the College of Sciences Engineering and Health of UWF and the Pall Corporation for SEM imaging.

Patterns of Diversity and Abundance of Carrion Insect Assemblages in the Natural Park “Hoces del Río Riaza” (Central Spain)

PubMed Central

Baz, Arturo; Cifrián, Blanca; Martín-Vega, Daniel

2014-01-01

Abstract The patterns of diversity and abundance of the carrion insect species in the different habitats of the Natural Park “Hoces del Río Riaza” (central Spain) were studied with the use of carrion-baited traps. Representativeness of the inventories was assessed with the calculation of randomized species richness curves and nonparametric estimators. Coleoptera families, Silphidae and Dermestidae, and Diptera families, Calliphoridae and Muscidae, were dominant in every sampling habitat, but differences in the patterns of diversity and abundance were found. Lusitanian oakwood and riparian forest were the most diverse habitats with high abundance of saprophagous species, whereas more open (i.e., exposed to continuous sunlight during the day) habitats showed lower diversity values and a different species composition and distribution of species abundance, favoring thermophilous species and necrophagous species with high tolerance to different environmental conditions. Differences in the bioclimatical features of the sampled habitats are suggested to explain the composition and diversity of the carrion insect assemblages in different environments. PMID:25368080

Endophytic bacterial community living in roots of healthy and 'Candidatus Phytoplasma mali'-infected apple (Malus domestica, Borkh.) trees.

PubMed

Bulgari, Daniela; Bozkurt, Adem I; Casati, Paola; Cağlayan, Kadriye; Quaglino, Fabio; Bianco, Piero A

2012-11-01

'Candidatus Phytoplasma mali', the causal agent of apple proliferation (AP) disease, is a quarantine pathogen controlled by chemical treatments against insect vectors and eradication of diseased plants. In accordance with the European Community guidelines, novel strategies should be developed for sustainable management of plant diseases by using resistance inducers (e.g. endophytes). A basic point for the success of this approach is the study of endophytic bacteria associated with plants. In the present work, endophytic bacteria living in healthy and 'Ca. Phytoplasma mali'-infected apple trees were described by cultivation-dependent and independent methods. 16S rDNA sequence analysis showed the presence of the groups Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, Chlamydiae, and Firmicutes. In detail, library analyses underscored 24 and 17 operational taxonomic units (OTUs) in healthy and infected roots, respectively, with a dominance of Betaproteobacteria. Moreover, differences in OTUs number and in CFU/g suggested that phytoplasmas could modify the composition of endophytic bacterial communities associated with infected plants. Intriguingly, the combination of culturing methods and cloning analysis allowed the identification of endophytic bacteria (e.g. Bacillus, Pseudomonas, and Burkholderia) that have been reported as biocontrol agents. Future research will investigate the capability of these bacteria to control 'Ca. Phytoplasma mali' in order to develop sustainable approaches for managing AP.

Genetic diversity and distribution patterns of host insects of Caterpillar Fungus Ophiocordyceps sinensis in the Qinghai-Tibet Plateau.

PubMed

Quan, Qing-Mei; Chen, Ling-Ling; Wang, Xi; Li, Shan; Yang, Xiao-Ling; Zhu, Yun-Guo; Wang, Mu; Cheng, Zhou

2014-01-01

The caterpillar fungus Ophiocordyceps sinensis is one of the most valuable medicinal fungi in the world, and it requires host insects in family Hepialidae (Lepidoptera) to complete its life cycle. However, the genetic diversity and phylogeographic structures of the host insects remain to be explored. We analyzed the genetic diversity and temporal and spatial distribution patterns of genetic variation of the host insects throughout the O. sinensis distribution. Abundant haplotype and nucleotide diversity mainly existed in the areas of Nyingchi, ShangriLa, and around the edge of the Qinghai-Tibet Plateau, where are considered as the diversity center or micro-refuges of the host insects of O. sinensis. However, there was little genetic variation among host insects from 72.1% of all populations, indicating that the host species composition might be relatively simple in large-scale O. sinensis populations. All host insects are monophyletic except for those from four O. sinensis populations around Qinghai Lake. Significant phylogeographic structure (NST>GST, P<0.05) was revealed for the monophyletic host insects, and the three major phylogenetic groups corresponded with specific geographical areas. The divergence of most host insects was estimated to have occurred at ca. 3.7 Ma, shortly before the rapid uplift of the QTP. The geographical distribution and star-like network of the haplotypes implied that most host insects were derived from the relicts of a once-widespread host that subsequently became fragmented. Neutrality tests, mismatch distribution analysis, and expansion time estimation confirmed that most host insects presented recent demographic expansions that began ca. 0.118 Ma in the late Pleistocene. Therefore, the genetic diversity and distribution of the present-day insects should be attributed to effects of the Qinghai-Tibet Plateau uplift and glacial advance/retreat cycles during the Quaternary ice age. These results provide valuable information to guide the protection and sustainable use of these host insects as well as O. sinensis.

Evolutionary Ecology of Multitrophic Interactions between Plants, Insect Herbivores and Entomopathogens.

PubMed

Shikano, Ikkei

2017-06-01

Plants play an important role in the interactions between insect herbivores and their pathogens. Since the seminal review by Cory and Hoover (2006) on plant-mediated effects on insect-pathogen interactions, considerable progress has been made in understanding the complexity of these tritrophic interactions. Increasing interest in the areas of nutritional and ecological immunology over the last decade have revealed that plant primary and secondary metabolites can influence the outcomes of insect-pathogen interactions by altering insect immune functioning and physical barriers to pathogen entry. Some insects use plant secondary chemicals and nutrients to prevent infections (prophylactic medication) and medicate to limit the severity of infections (therapeutic medication). Recent findings suggest that there may be selectable plant traits that enhance entomopathogen efficacy, suggesting that entomopathogens could potentially impose selection pressure on plant traits that improve both pathogen and plant fitness. Moreover, plants in nature are inhabited by diverse communities of microbes, in addition to entomopathogens, some of which can trigger immune responses in insect herbivores. Plants are also shared by numerous other herbivorous arthropods with different modes of feeding that can trigger different defensive responses in plants. Some insect symbionts and gut microbes can degrade ingested defensive phytochemicals and be orally secreted onto wounded plant tissue during herbivory to alter plant defenses. Since non-entomopathogenic microbes and other arthropods are likely to influence the outcomes of plant-insect-entomopathogen interactions, I discuss a need to consider these multitrophic interactions within the greater web of species interactions.

Engineered Surfaces for Mitigation of Insect Residue Adhesion

NASA Technical Reports Server (NTRS)

Siochi, Emilie J.; Smith, Joseph G.; Wohl, Christopher J.; Gardner, J. M.; Penner, Ronald K.; Connell, John W.

2013-01-01

Maintenance of laminar flow under operational flight conditions is being investigated under NASA s Environmentally Responsible Aviation (ERA) Program. Among the challenges with natural laminar flow is the accretion of residues from insect impacts incurred during takeoff or landing. Depending on air speed, temperature, and wing structure, the critical residue height for laminar flow disruption can be as low as 4 microns near the leading edge. In this study, engineered surfaces designed to minimize insect residue adhesion were examined. The coatings studied included chemical compositions containing functional groups typically associated with abhesive (non-stick) surfaces. To reduce surface contact by liquids and enhance abhesion, the engineered surfaces consisted of these coatings doped with particulate additives to generate random surface topography, as well as coatings applied to laser ablated surfaces having precision patterned topographies. Performance evaluation of these surfaces included contact angle goniometry of pristine coatings and profilometry of surfaces after insect impacts were incurred in laboratory scale tests, wind tunnel tests and flight tests. The results illustrate the complexity of designing antifouling surfaces for effective insect contamination mitigation under dynamic conditions and suggest that superhydrophobic surfaces may not be the most effective solution for preventing insect contamination on aircraft wing leading edges.

Seasonal bat activity related to insect emergence at three temperate lakes.

PubMed

Salvarina, Ioanna; Gravier, Dorian; Rothhaupt, Karl-Otto

2018-04-01

Knowledge of aquatic food resources entering terrestrial systems is important for food web studies and conservation planning. Bats, among other terrestrial consumers, often profit from aquatic insect emergence and their activity might be closely related to such events. However, there is a lack of studies which monitor bat activity simultaneously with aquatic insect emergence, especially from lakes. Thus, our aim was to understand the relationship between insect emergence and bat activity, and investigate whether there is a general spatial or seasonal pattern at lakeshores. We assessed whole-night bat activity using acoustic monitoring and caught emerging and aerial flying insects at three different lakes through three seasons. We predicted that insect availability and seasonality explain the variation in bat activity, independent of the lake size and characteristics. Spatial (between lakes) differences of bat activity were stronger than temporal (seasonal) differences. Bat activity did not always correlate to insect emergence, probably because other factors, such as habitat characteristics, or bats' energy requirements, play an important role as well. Aerial flying insects explained bat activity better than the emerged aquatic insects in the lake with lowest insect emergence. Bats were active throughout the night with some activity peaks, and the pattern of their activity also differed among lakes and seasons. Lakes are important habitats for bats, as they support diverse bat communities and activity throughout the night and the year when bats are active. Our study highlights that there are spatial and temporal differences in bat activity and its hourly nocturnal pattern, that should be considered when investigating aquatic-terrestrial interactions or designing conservation and monitoring plans.

Multidimensional approaches for studying plant defence against insects: from ecology to omics and synthetic biology.

PubMed

Barah, Pankaj; Bones, Atle M

2015-02-01

The biggest challenge for modern biology is to integrate multidisciplinary approaches towards understanding the organizational and functional complexity of biological systems at different hierarchies, starting from the subcellular molecular mechanisms (microscopic) to the functional interactions of ecological communities (macroscopic). The plant-insect interaction is a good model for this purpose with the availability of an enormous amount of information at the molecular and the ecosystem levels. Changing global climatic conditions are abruptly resetting plant-insect interactions. Integration of discretely located heterogeneous information from the ecosystem to genes and pathways will be an advantage to understand the complexity of plant-insect interactions. This review will present the recent developments in omics-based high-throughput experimental approaches, with particular emphasis on studying plant defence responses against insect attack. The review highlights the importance of using integrative systems approaches to study plant-insect interactions from the macroscopic to the microscopic level. We analyse the current efforts in generating, integrating and modelling multiomics data to understand plant-insect interaction at a systems level. As a future prospect, we highlight the growing interest in utilizing the synthetic biology platform for engineering insect-resistant plants. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Indicators: Zooplankton

EPA Pesticide Factsheets

Zooplankton are small, free-floating aquatic microorganisms including crustaceans, rotifers, open water insect larvae, and aquatic mites. The zooplankton community is composed of both primary consumers and secondary consumers.

Light Color Attraction and Dietary Sugar Composition for Several Mosquito (Diptera: Culicidae) Species Found in North Central Florida

DTIC Science & Technology

1998-07-02

Niwot, CO. Koptur, S. 1992. Extrafloral nectar-mediated interactions between insects and plants , pp. 81-129. In E. A. Bemays [ed.]. Insect- Plant ...Standards- . .■ 45 Results and Discussion 45 Ecological Significance ofHoneydew in Mosquito Diet 46 Sugar Feeding Field Observations 48 4...of combined standards (ca. 0.1%) for common sugars associated with plants . Multiple peaks of the same sugar are anomeric forms .35 2-2

Wild Herbivore Grazing Enhances Insect Diversity over Livestock Grazing in an African Grassland System

PubMed Central

Roets, Francois; Samways, Michael J.

2016-01-01

Southern Africa’s grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural grazing dynamics, which could have an impact on the long-term value of ENs for insects. Here we compared dung beetle, butterfly and grasshopper diversity in ENs across a landscape mosaic of timber plantations, where 1) wild megaherbivores were maintained, 2) in ENs where these herbivores were replaced by livestock and, 3) in a nearby World Heritage PA which retained its natural complement of megaherbivores. Sites in the PA far from any plantation were similar in composition to those in the wild grazed EN. Presence of the wild grazers improved the alpha- and beta-diversity of all focal insect taxa when compared to domestic grazing. Furthermore, species composition shows significant differences between the two grazing systems indicating that an assemblage of native large mammals facilitates insect diversity conservation. We support the maintenance or introduction of large native mammals in ENs or similar conservation areas in production landscapes to simulate the ecological conditions and natural heterogeneity in nearby PAs. PMID:27783685

Wild Herbivore Grazing Enhances Insect Diversity over Livestock Grazing in an African Grassland System.

PubMed

Pryke, James S; Roets, Francois; Samways, Michael J

2016-01-01

Southern Africa's grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural grazing dynamics, which could have an impact on the long-term value of ENs for insects. Here we compared dung beetle, butterfly and grasshopper diversity in ENs across a landscape mosaic of timber plantations, where 1) wild megaherbivores were maintained, 2) in ENs where these herbivores were replaced by livestock and, 3) in a nearby World Heritage PA which retained its natural complement of megaherbivores. Sites in the PA far from any plantation were similar in composition to those in the wild grazed EN. Presence of the wild grazers improved the alpha- and beta-diversity of all focal insect taxa when compared to domestic grazing. Furthermore, species composition shows significant differences between the two grazing systems indicating that an assemblage of native large mammals facilitates insect diversity conservation. We support the maintenance or introduction of large native mammals in ENs or similar conservation areas in production landscapes to simulate the ecological conditions and natural heterogeneity in nearby PAs.

Metacommunity ecology meets biogeography: effects of geographical region, spatial dynamics and environmental filtering on community structure in aquatic organisms.

PubMed

Heino, Jani; Soininen, Janne; Alahuhta, Janne; Lappalainen, Jyrki; Virtanen, Risto

2017-01-01

Metacommunity patterns and underlying processes in aquatic organisms have typically been studied within a drainage basin. We examined variation in the composition of six freshwater organismal groups across various drainage basins in Finland. We first modelled spatial structures within each drainage basin using Moran eigenvector maps. Second, we partitioned variation in community structure among three groups of predictors using constrained ordination: (1) local environmental variables, (2) spatial variables, and (3) dummy variable drainage basin identity. Third, we examined turnover and nestedness components of multiple-site beta diversity, and tested the best fit patterns of our datasets using the "elements of metacommunity structure" analysis. Our results showed that basin identity and local environmental variables were significant predictors of community structure, whereas within-basin spatial effects were typically negligible. In half of the organismal groups (diatoms, bryophytes, zooplankton), basin identity was a slightly better predictor of community structure than local environmental variables, whereas the opposite was true for the remaining three organismal groups (insects, macrophytes, fish). Both pure basin and local environmental fractions were, however, significant after accounting for the effects of the other predictor variable sets. All organismal groups exhibited high levels of beta diversity, which was mostly attributable to the turnover component. Our results showed consistent Clementsian-type metacommunity structures, suggesting that subgroups of species responded similarly to environmental factors or drainage basin limits. We conclude that aquatic communities across large scales are mostly determined by environmental and basin effects, which leads to high beta diversity and prevalence of Clementsian community types.

Beyond 16S rRNA Community Profiling: Intra-Species Diversity in the Gut Microbiota

PubMed Central

Ellegaard, Kirsten M.; Engel, Philipp

2016-01-01

Interactions with microbes affect many aspects of animal biology, including immune system development, nutrition and health. In vertebrates, the gut microbiota is dominated by a small subset of phyla, but the species composition within these phyla is typically not conserved. Moreover, several recent studies have shown that bacterial species in the gut are composed of a multitude of strains, which frequently co-exist in their host, and may be host-specific. However, since the study of intra-species diversity is challenging, particularly in the setting of complex, host-associated microbial communities, our current understanding of the distribution, evolution and functional relevance of intra-species diversity in the gut is scarce. In order to unravel how genomic diversity translates into phenotypic diversity, community analyses going beyond 16S rRNA profiling, in combination with experimental approaches, are needed. Recently, the honeybee has emerged as a promising model for studying gut bacterial communities, particularly in terms of strain-level diversity. Unlike most other invertebrates, the honeybee gut is colonized by a remarkably consistent and specific core microbiota, which is dominated by only eight bacterial species. As for the vertebrate gut microbiota, these species are composed of highly diverse strains suggesting that similar evolutionary forces shape gut community structures in vertebrates and social insects. In this review, we outline current knowledge on the evolution and functional relevance of strain diversity within the gut microbiota, including recent insights gained from mammals and other animals such as the honeybee. We discuss methodological approaches and propose possible future avenues for studying strain diversity in complex bacterial communities. PMID:27708630

Beyond 16S rRNA Community Profiling: Intra-Species Diversity in the Gut Microbiota.

PubMed

Ellegaard, Kirsten M; Engel, Philipp

2016-01-01

Interactions with microbes affect many aspects of animal biology, including immune system development, nutrition and health. In vertebrates, the gut microbiota is dominated by a small subset of phyla, but the species composition within these phyla is typically not conserved. Moreover, several recent studies have shown that bacterial species in the gut are composed of a multitude of strains, which frequently co-exist in their host, and may be host-specific. However, since the study of intra-species diversity is challenging, particularly in the setting of complex, host-associated microbial communities, our current understanding of the distribution, evolution and functional relevance of intra-species diversity in the gut is scarce. In order to unravel how genomic diversity translates into phenotypic diversity, community analyses going beyond 16S rRNA profiling, in combination with experimental approaches, are needed. Recently, the honeybee has emerged as a promising model for studying gut bacterial communities, particularly in terms of strain-level diversity. Unlike most other invertebrates, the honeybee gut is colonized by a remarkably consistent and specific core microbiota, which is dominated by only eight bacterial species. As for the vertebrate gut microbiota, these species are composed of highly diverse strains suggesting that similar evolutionary forces shape gut community structures in vertebrates and social insects. In this review, we outline current knowledge on the evolution and functional relevance of strain diversity within the gut microbiota, including recent insights gained from mammals and other animals such as the honeybee. We discuss methodological approaches and propose possible future avenues for studying strain diversity in complex bacterial communities.

Seasonal Blowfly Distribution and Abundance in Fragmented Landscapes. Is It Useful in Forensic Inference about Where a Corpse Has Been Decaying?

PubMed Central

Zabala, Jabi; Díaz, Beatriz; Saloña-Bordas, Marta I.

2014-01-01

Blowflies are insects of forensic interest as they may indicate characteristics of the environment where a body has been laying prior to the discovery. In order to estimate changes in community related to landscape and to assess if blowfly species can be used as indicators of the landscape where a corpse has been decaying, we studied the blowfly community and how it is affected by landscape in a 7,000 km2 region during a whole year. Using baited traps deployed monthly we collected 28,507 individuals of 10 calliphorid species, 7 of them well represented and distributed in the study area. Multiple Analysis of Variance found changes in abundance between seasons in the 7 analyzed species, and changes related to land use in 4 of them (Calliphora vomitoria, Lucilia ampullacea, L. caesar and L. illustris). Generalised Linear Model analyses of abundance of these species compared with landscape descriptors at different scales found only a clear significant relationship between summer abundance of C. vomitoria and distance to urban areas and degree of urbanisation. This relationship explained more deviance when considering the landscape composition at larger geographical scales (up to 2,500 m around sampling site). For the other species, no clear relationship between land uses and abundance was found, and therefore observed changes in their abundance patterns could be the result of other variables, probably small changes in temperature. Our results suggest that blowfly community composition cannot be used to infer in what kind of landscape a corpse has decayed, at least in highly fragmented habitats, the only exception being the summer abundance of C. vomitoria. PMID:24918607

Aquatic insect community structure under the influence of small dams in a stream of the Mogi-Guaçu river basin, state of São Paulo.

PubMed

Saulino, H H L; Corbi, J J; Trivinho-Strixino, S

2014-02-01

The fragmentation of lotic systems caused by construction of dams has modified many aquatic communities. The objective of this study was to analyse changes in the aquatic insect community structure by discontinuity of habitat created by dams along the Ribeirão das Anhumas, a sub-basin of the Mogi-Guaçu River (state of São Paulo, Brazil). Entomofauna collection was carried out in 10 segments upstream and downstream of five dams along the longitudinal profile of the stream, with a quick sampling method using a D net (mesh 250 mm) with 2 minutes of sampling effort. The insects were sorted and identified to the lowest possible taxonomic level and analysed by the Shannon diversity index, β diversity, richness estimated by rarefaction curves and relative participation of functional feeding groups. The results showed a slight reduction in diversity in the downstream segments, as well as along the longitudinal profile of the stream. However, there were no significant differences in abundance and richness between the upstream and downstream segments, indicating that the dams did not influence these variables. Differences were observed in the functional feeding groups along the longitudinal profile. Predator and gatherer insects were dominant in all segments analysed. The feeding group of shredders was more abundant in the segment DSIII with the participation of Marilia Müller (Odontoceridae - Trichoptera), although we observed a decrease of shredders and scrapers with the decrease of the canopy cover reducing values of β diversity in the continuum of Ribeirão das Anhumas. This result demonstrated the importance of the conservation of the riparian vegetation in order to maintain the integrity of the stream.

Aboveground Whitefly Infestation-Mediated Reshaping of the Root Microbiota.

PubMed

Kong, Hyun G; Kim, Byung K; Song, Geun C; Lee, Soohyun; Ryu, Choong-Min

2016-01-01

Plants respond to various types of herbivore and pathogen attack using well-developed defensive machinery designed for self-protection. Infestation from phloem-sucking insects such as whitefly and aphid on plant leaves was previously shown to influence both the saprophytic and pathogenic bacterial community in the plant rhizosphere. However, the modulation of the root microbial community by plants following insect infestation has been largely unexplored. Only limited studies of culture-dependent bacterial diversity caused by whitefly and aphid have been conducted. In this study, to obtain a complete picture of the belowground microbiome community, we performed high-speed and high-throughput next-generation sequencing. We sampled the rhizosphere soils of pepper seedlings at 0, 1, and 2 weeks after whitefly infestation versus the water control. We amplified a partial 16S ribosomal RNA gene (V1-V3 region) by polymerase chain reaction with specific primers. Our analysis revealed that whitefly infestation reshaped the overall microbiota structure compared to that of the control rhizosphere, even after 1 week of infestation. Examination of the relative abundance distributions of microbes demonstrated that whitefly infestation shifted the proteobacterial groups at week 2. Intriguingly, the population of Pseudomonadales of the class Gammaproteobacteria significantly increased after 2 weeks of whitefly infestation, and the fluorescent Pseudomonas spp. recruited to the rhizosphere were confirmed to exhibit insect-killing capacity. Additionally, three taxa, including Caulobacteraceae, Enterobacteriaceae, and Flavobacteriaceae, and three genera, including Achromobacter, Janthinobacterium, and Stenotrophomonas, were the most abundant bacterial groups in the whitefly infested plant rhizosphere. Our results indicate that whitefly infestation leads to the recruitment of specific groups of rhizosphere bacteria by the plant, which confer beneficial traits to the host plant. This study provides a new framework for investigating how aboveground insect feeding modulates the belowground microbiome.

Characteristics of modern pollen rain and the relationship to vegetation in sagebrush-steppe environments of Montana, USA

NASA Astrophysics Data System (ADS)

Briles, C.; Bryant, V.

2010-12-01

Variations in pollen production and dispersal characteristics among plant species complicate our ability to determine direct relationships between deposited pollen and actual vegetation. In order to better understand modern pollen-vegetation relationships, we analyzed pollen from 61 samples taken from sagebrush-steppe environments across Montana and compared them with the actual vegetation composition at each site. We also determined to what degree sagebrush-steppe communities can be geographically distinguished from one another based on their pollen signature. Pollen preservation was good, especially in wetter environments, with pollen degradataion ranging from 4-15%. Diploxylon Pinus was the primary contributor to the pollen rain, even in plots where pine trees did not occur or were several kilometers from the plot. Artemisia and grass pollen are underrepresented in the soils samples, while Chenopodiaceae and Juniperus pollen are overrepresented when compared to actual vegetation composition. Insect-pollinated species are present only in very minor amounts in the soil samples, even though some (e.g., Brassica) are abundant in the plots. In general, pollen spectra show significant differences between regions, however, within each region the individual spectra are not statistically significant from one another. An understanding of modern pollen-vegetation relationships and the palynological “fingerprint” of sagebrush-steppe communities aid in climatic and ecological interpretations of fossil pollen assemblages. The data also provide important control samples for forensics studies that use pollen to geolocate an object or person to a crime scene.

Emergence flux declines disproportionately to larval density along a stream metals gradient

USGS Publications Warehouse

Schmidt, Travis S.; Kraus, Johanna M.; Walters, David M.; Wanty, Richard B.

2013-01-01

Effects of contaminants on adult aquatic insect emergence are less well understood than effects on insect larvae. We compared responses of larval density and adult emergence along a metal contamination gradient. Nonlinear threshold responses were generally observed for larvae and emergers. Larval densities decreased significantly at low metal concentrations but precipitously at concentrations of metal mixtures above aquatic life criteria (Cumulative Criterion Accumulation Ratio (CCAR) ≥ 1). In contrast, adult emergence declined precipitously at low metal concentrations (CCAR ≤ 1), followed by a modest decline above this threshold. Adult emergence was a more sensitive indicator of the effect of low metals concentrations on aquatic insect communities compared to larvae, presumably because emergence is limited by a combination of larval survival and other factors limiting successful emergence. Thus effects of exposure to larvae are not manifest until later in life (during metamorphosis and emergence). This loss in emergence reduces prey subsidies to riparian communities at concentrations considered safe for aquatic life. Our results also challenge the widely held assumption that adult emergence is a constant proportion of larval densities in all streams.

Carryover effects of larval exposure to different environmental bacteria drive adult trait variation in a mosquito vector

PubMed Central

Dickson, Laura B.; Jiolle, Davy; Minard, Guillaume; Moltini-Conclois, Isabelle; Volant, Stevenn; Ghozlane, Amine; Bouchier, Christiane; Ayala, Diego; Paupy, Christophe; Moro, Claire Valiente; Lambrechts, Louis

2017-01-01

Conditions experienced during larval development of holometabolous insects can affect adult traits, but whether differences in the bacterial communities of larval development sites contribute to variation in the ability of insect vectors to transmit human pathogens is unknown. We addressed this question in the mosquito Aedes aegypti, a major arbovirus vector breeding in both sylvatic and domestic habitats in Sub-Saharan Africa. Targeted metagenomics revealed differing bacterial communities in the water of natural breeding sites in Gabon. Experimental exposure to different native bacterial isolates during larval development resulted in significant differences in pupation rate and adult body size but not life span. Larval exposure to an Enterobacteriaceae isolate resulted in decreased antibacterial activity in adult hemolymph and reduced dengue virus dissemination titer. Together, these data provide the proof of concept that larval exposure to different bacteria can drive variation in adult traits underlying vectorial capacity. Our study establishes a functional link between larval ecology, environmental microbes, and adult phenotypic variation in a holometabolous insect vector. PMID:28835919

Secondary production of benthic insects in three cold-desert streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaines, W.L.

1987-07-01

Aquatic insect production was studied in three cold-desert streams in eastern Washington (Douglas Creek, Snively Springs, and Rattlesnake Springs). The size-frequency method was applied to individual taxa to estimate total insect production. production was also assessed for functional groups and trophic levels in each stream. Optioservus sp. (riffle beetles) and Baetis sp. (mayflies) accounted for 72% of the total insect numbers and 50% of the total biomass in Douglas Creek. Baetis sp. accounted for 42% of the total insect numbers and 25% of the total biomass in Snively Springs. Simulium sp. (blackflies) and Baetis sp. comprised 74% of the totalmore » insect numbers and 55% of the total biomass in Rattlesnake Springs. Grazer-scrapers (49%) and collectors (48%) were the most abundant functional groups in Douglas Creek. Collectors were the most abundant functional group in Snively Springs and Rattlesnake Springs. Herbivores and detritivores were the most abundant trophic level in Snively Springs and Rattlesnake Springs. Dipterans (midges and blackflies) were the most productive taxa within the study streams, accounting for 40% to 70% of the total community production. Production by collectors and detritivores was the highest of all functional groups and trophic levels in all study streams.« less

Self-assembled carbon nanotube honeycomb networks using a butterfly wing template as a multifunctional nanobiohybrid.

PubMed

Miyako, Eijiro; Sugino, Takushi; Okazaki, Toshiya; Bianco, Alberto; Yudasaka, Masako; Iijima, Sumio

2013-10-22

Insect wings have many unique and complex nano/microstructures that are presently beyond the capabilities of any current technology to reproduce them artificially. In particular, Morpho butterflies are an attractive type of insect because their multifunctional wings are composed of nano/microstructures. In this paper, we show that carbon nanotube-containing composite adopts honeycomb-shaped networks when simply self-assembled on Morpho butterfly wings used as a template. The unique nano/microstructure of the composites exhibits multifunctionalities such as laser-triggered remote-heating, high electrical conductivity, and repetitive DNA amplification. Our present study highlights the important progress that has been made toward the development of smart nanobiomaterials for various applications such as digital diagnosis, soft wearable electronic devices, photosensors, and photovoltaic cells.

Spring succession of necrophilous insects on wildlife carcasses in Louisiana.

PubMed

Watson, E J; Carlton, C E

2003-05-01

Seven fresh animal carcasses were monitored throughout decomposition in a mixed flatwood forest in East Baton Rouge Parish, LA from 1 April to 1 July 1999. Succession patterns of necrophilous insects were documented for the following: one Louisiana black bear (threatened species), two white-tailed deer, two alligators, and two swine as the experimental reference. Our results suggest variation in the species composition of necrophilous insects among animal carcass types. A total of 93 arthropod species, from 46 families and three classes, were manually collected from the seven carcasses. Only 19 insect species were collected on all four animal types and were represented by eight families: Coleoptera: Histeridae, Nitidulidae, Silphidae, Staphylinidae; Diptera: Calliphoridae, Muscidae, Piophilidae, Sepsidae. Eleven of the 46 families were not collected at either alligator site but were observed at bear, deer, and swine carrion: Coleoptera: Cleridae, Dermestidae, Geotrupidae, Scarabaeidae; Diptera: Micropezidae, Sarcophagidae, Syrphidae; Hymenoptera: Apidae; Lepidoptera: Nymphalidae; and Odonata: Libellulidae. Residency and succession patterns of necrophilous insects are presented for each animal type with particular emphasis on selected fly (Calliphoridae, Muscidae, Piophilidae, Stratiomyidae) and beetle species (Cleridae, Dermestidae, Histeridae, Nitidulidae, Silphidae, Staphylinidae).

Helicoverpa zea (Lepidoptera: Noctuidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) Responses to Sorghum bicolor (Poales: Poaceae) Tissues From Lowered Lignin Lines

PubMed Central

Dowd, Patrick F.; Sattler, Scott E.

2015-01-01

The presence of lignin within biomass impedes the production of liquid fuels. Plants with altered lignin content and composition are more amenable to lignocellulosic conversion to ethanol and other biofuels but may be more susceptible to insect damage where lignin is an important resistance factor. However, reduced lignin lines of switchgrasses still retained insect resistance in prior studies. Therefore, we hypothesized that sorghum lines with lowered lignin content will also retain insect resistance. Sorghum excised leaves and stalk pith Sorghum bicolor (L.) Moench (Poales: Poaceae) from near isogenic brown midrib (bmr) 6 and 12 mutants lines, which have lowered lignin content and increased lignocellulosic ethanol conversion efficiency, were examined for insect resistance relative to wild-type (normal BTx623). Greenhouse and growth chamber grown plant tissues were fed to first-instar larvae of corn earworms, Helicoverpa zea (Boddie) and fall armyworms Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), two sorghum major pests. Younger bmr leaves had significantly greater feeding damage in some assays than wild-type leaves, but older bmr6 leaves generally had significantly less damage than wild-type leaves. Caterpillars feeding on the bmr6 leaves often weighed significantly less than those feeding on wild-type leaves, especially in the S. frugiperda assays. Larvae fed the pith from bmr stalks had significantly higher mortality compared with those larvae fed on wild-type pith, which suggested that bmr pith was more toxic. Thus, reducing lignin content or changing subunit composition of bioenergy grasses does not necessarily increase their susceptibility to insects and may result in increased resistance, which would contribute to sustainable production. PMID:25601946

Stem nematode counteracts plant resistance of aphids in alfalfa, Medicago sativa.

PubMed

Ramirez, Ricardo A; Spears, Lori R

2014-10-01

Plants are exploited by a diverse community of insect herbivores and phytopathogens that interact indirectly through plant-mediated interactions. Generally, plants are thought to respond to insects and pathogens through different defensive signaling pathways. As plants are selected for resistance to one phytophagous organism type (insect vs. pathogen) in managed systems, it is not clear how this selection may affect community interactions. This study examined the effect of nematode-resistant varieties on aphid (Acyrthosiphon pisum) suppression, and then determined how infection by the stem nematode, Ditylenchus dipsaci, mediated ecological effects on aphids and on plant defense proteins. Four alfalfa (Medicago sativa) varieties were selected with resistance to nematodes only (+,-), aphids only (-,+), nematodes and aphids (+,+), and susceptibility to nematodes and aphids (-,-). Field and greenhouse experiments were conducted to isolate the effect of nematode infection and aphid abundance on each variety. We found that varieties resistant to nematode, regardless of aphid resistance, had the lowest aphid counts, suggesting possible cross-resistance. Aphid abundance, however, increased when plants were exposed to nematodes. Resistant varieties were associated with elevated saponins but these compounds were not affected by insect or pathogen feeding. Concentrations of peroxidases and trypsin inhibitors, however, were increased in nematode resistant varieties when exposed to nematodes and aphids, respectively. The patterns of plant defense were variable, and a combination of resistance traits and changes in nutrient availability may drive positive interactions between nematodes and aphids aboveground.

i5k | National Agricultural Library

Science.gov Websites

genome browser, and the Apollo manual curation service. Over 50 arthropod genomes are now part of the i5k (done by Dan Hughes at Baylor) with manual annotations by the research community (done via Web Apollo with manual annotations by the research community (via the Apollo manual annotation software). insects

Diversity and phenology of the generalist predator community in apple orchards of Central Washington State (insecta, araneae)

USDA-ARS?s Scientific Manuscript database

Predatory insects and spiders were collected from apple orchards in two geographic regions of Central Washington State to assess seasonal phenology and diversity of the generalist predator community. Arthropods were collected from orchard canopy every 3-7 d over two growing seasons (March-October) ...

Longevity-modulating effects of symbiosis: insights from Drosophila-Wolbachia interaction.

PubMed

Maistrenko, Oleksandr M; Serga, Svitlana V; Vaiserman, Alexander M; Kozeretska, Iryna A

2016-11-01

Microbial communities are known to significantly affect various fitness components and survival of their insect hosts, including Drosophila. The composition of symbiotic microbiota has been shown to change with the host's aging. It is unclear whether these changes are caused by the aging process or, vice versa, they affect the host's aging and longevity. Recent findings indicate that fitness and lifespan of Drosophila are affected by endosymbiotic bacteria Wolbachia. These effects, however, are inconsistent and have been reported both to extend and shorten longevity. The main molecular pathways underlying the lifespan-modulating effects of Wolbachia remain unclear, however insulin/insulin-like growth factor, immune deficiency, ecdysteroid synthesis and signaling and c-Jun N-terminal kinase pathways as well as heat shock protein synthesis and autophagy have been proposed to play a role. Here we revise the current evidence that elucidates the impact of Wolbachia endosymbionts on the aging processes in Drosophila.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suen, Garret; Barry, Kerrie; Goodwin, Lynne

Herbivores can gain indirect access to recalcitrant carbon present in plant cell walls through symbiotic associations with lignocellulolytic microbes. A paradigmatic example is the leaf-cutter ant (Tribe: Attini), which uses fresh leaves to cultivate a fungus for food in specialized gardens. Using a combination of sugar composition analyses, metagenomics, and whole-genome sequencing, we reveal that the fungus garden microbiome of leaf-cutter ants is composed of a diverse community of bacteria with high plant biomass-degrading capacity. Comparison of this microbiome?s predicted carbohydrate-degrading enzyme profile with other metagenomes shows closest similarity to the bovine rumen, indicating evolutionary convergence of plant biomass degradingmore » potential between two important herbivorous animals. Genomic and physiological characterization of two dominant bacteria in the fungus garden microbiome provides evidence of their capacity to degrade cellulose. Given the recent interest in cellulosic biofuels, understanding how large-scale and rapid plant biomass degradation occurs in a highly evolved insect herbivore is of particular relevance for bioenergy.« less

Mixed genotype transmission bodies and virions contribute to the maintenance of diversity in an insect virus

PubMed Central

Clavijo, Gabriel; Williams, Trevor; Muñoz, Delia; Caballero, Primitivo; López-Ferber, Miguel

2010-01-01

An insect nucleopolyhedrovirus naturally survives as a mixture of at least nine genotypes. Infection by multiple genotypes results in the production of virus occlusion bodies (OBs) with greater pathogenicity than those of any genotype alone. We tested the hypothesis that each OB contains a genotypically diverse population of virions. Few insects died following inoculation with an experimental two-genotype mixture at a dose of one OB per insect, but a high proportion of multiple infections were observed (50%), which differed significantly from the frequencies predicted by a non-associated transmission model in which genotypes are segregated into distinct OBs. By contrast, insects that consumed multiple OBs experienced higher mortality and infection frequencies did not differ significantly from those of the non-associated model. Inoculation with genotypically complex wild-type OBs indicated that genotypes tend to be transmitted in association, rather than as independent entities, irrespective of dose. To examine the hypothesis that virions may themselves be genotypically heterogeneous, cell culture plaques derived from individual virions were analysed to reveal that one-third of virions was of mixed genotype, irrespective of the genotypic composition of the OBs. We conclude that co-occlusion of genotypically distinct virions in each OB is an adaptive mechanism that favours the maintenance of virus diversity during insect-to-insect transmission. PMID:19939845

Reconstructing community assembly in time and space reveals enemy escape in a Western Palearctic insect community.

PubMed

Stone, Graham N; Lohse, Konrad; Nicholls, James A; Fuentes-Utrilla, Pablo; Sinclair, Frazer; Schönrogge, Karsten; Csóka, György; Melika, George; Nieves-Aldrey, Jose-Luis; Pujade-Villar, Juli; Tavakoli, Majide; Askew, Richard R; Hickerson, Michael J

2012-03-20

How geographically widespread biological communities assemble remains a major question in ecology. Do parallel population histories allow sustained interactions (such as host-parasite or plant-pollinator) among species, or do discordant histories necessarily interrupt them? Though few empirical data exist, these issues are central to our understanding of multispecies evolutionary dynamics. Here we use hierarchical approximate Bayesian analysis of DNA sequence data for 12 herbivores and 19 parasitoids to reconstruct the assembly of an insect community spanning the Western Palearctic and assess the support for alternative host tracking and ecological sorting hypotheses. We show that assembly occurred primarily by delayed host tracking from a shared eastern origin. Herbivores escaped their enemies for millennia before parasitoid pursuit restored initial associations, with generalist parasitoids no better able to track their hosts than specialists. In contrast, ecological sorting played only a minor role. Substantial turnover in host-parasitoid associations means that coevolution must have been diffuse, probably contributing to the parasitoid generalism seen in this and similar systems. Reintegration of parasitoids after host escape shows these communities to have been unsaturated throughout their history, arguing against major roles for parasitoid niche evolution or competition during community assembly. Copyright © 2012 Elsevier Ltd. All rights reserved.

Host plant species determines symbiotic bacterial community mediating suppression of plant defenses

PubMed Central

Chung, Seung Ho; Scully, Erin D.; Peiffer, Michelle; Geib, Scott M.; Rosa, Cristina; Hoover, Kelli; Felton, Gary W.

2017-01-01

Herbivore associated bacteria are vital mediators of plant and insect interactions. Host plants play an important role in shaping the gut bacterial community of insects. Colorado potato beetles (CPB; Leptinotarsa decemlineata) use several Solanum plants as hosts in their natural environment. We previously showed that symbiotic gut bacteria from CPB larvae suppressed jasmonate (JA)-induced defenses in tomato. However, little is known about how changes in the bacterial community may be involved in the manipulation of induced defenses in wild and cultivated Solanum plants of CPB. Here, we examined suppression of JA-mediated defense in wild and cultivated hosts of CPB by chemical elicitors and their symbiotic bacteria. Furthermore, we investigated associations between the gut bacterial community and suppression of plant defenses using 16 S rRNA amplicon sequencing. Symbiotic bacteria decreased plant defenses in all Solanum hosts and there were different gut bacterial communities in CPB fed on different host plants. When larvae were reared on different hosts, defense suppression differed among host plants. These results demonstrate that host plants influence herbivore gut bacterial communities and consequently affect the herbivore’s ability to manipulate JA-mediated plant defenses. Thus, the presence of symbiotic bacteria that suppress plant defenses might help CPB adapt to host plants. PMID:28045052

Host plant species determines symbiotic bacterial community mediating suppression of plant defenses.

PubMed

Chung, Seung Ho; Scully, Erin D; Peiffer, Michelle; Geib, Scott M; Rosa, Cristina; Hoover, Kelli; Felton, Gary W

2017-01-03

Herbivore associated bacteria are vital mediators of plant and insect interactions. Host plants play an important role in shaping the gut bacterial community of insects. Colorado potato beetles (CPB; Leptinotarsa decemlineata) use several Solanum plants as hosts in their natural environment. We previously showed that symbiotic gut bacteria from CPB larvae suppressed jasmonate (JA)-induced defenses in tomato. However, little is known about how changes in the bacterial community may be involved in the manipulation of induced defenses in wild and cultivated Solanum plants of CPB. Here, we examined suppression of JA-mediated defense in wild and cultivated hosts of CPB by chemical elicitors and their symbiotic bacteria. Furthermore, we investigated associations between the gut bacterial community and suppression of plant defenses using 16 S rRNA amplicon sequencing. Symbiotic bacteria decreased plant defenses in all Solanum hosts and there were different gut bacterial communities in CPB fed on different host plants. When larvae were reared on different hosts, defense suppression differed among host plants. These results demonstrate that host plants influence herbivore gut bacterial communities and consequently affect the herbivore's ability to manipulate JA-mediated plant defenses. Thus, the presence of symbiotic bacteria that suppress plant defenses might help CPB adapt to host plants.

Community structure of aquatic insects in the Esparza River, Costa Rica.

PubMed

Herrera-Vásquez, Jonathan

2009-01-01

This study focused on the structure of the aquatic insect community in spatial and temporal scales in the Esparza River. The river was sampled for one full year throughout 2007. During the dry season low flow months, five sampling points were selected in two different habitats (currents and pools), with five replicates per sample site. During the wet season with peak rain, only the data in the "current habitat" were sampled at each site. Specimens present in the different substrates were collected and preserved in situ. A nested ANOVA was then applied to the data to determine richness and density as the response variables. The variations in temporal and spatial scales were analyzed using width, depth and discharge of the river, and then analyzed using a nested ANOVA. Only a correlation of 51% similarity in richness was found, while in spatial scale, richness showed significant variation between sampling sites, but not between habitats. However, the temporal scale showed significant differences between habitats. Density showed differences between sites and habitats during the dry season in the spatial scale, while in the temporal scale significant variation was found between sampling sites. Width varied between habitats during the dry season, but not between sampling points. Depth showed differences between sampling sites and season. This work studies the importance of community structure of aquatic insects in rivers, and its relevance for the quality of water in rivers and streams.

Host-symbiont co-speciation and reductive genome evolution in gut symbiotic bacteria of acanthosomatid stinkbugs

PubMed Central

Kikuchi, Yoshitomo; Hosokawa, Takahiro; Nikoh, Naruo; Meng, Xian-Ying; Kamagata, Yoichi; Fukatsu, Takema

2009-01-01

Background Host-symbiont co-speciation and reductive genome evolution have been commonly observed among obligate endocellular insect symbionts, while such examples have rarely been identified among extracellular ones, the only case reported being from gut symbiotic bacteria of stinkbugs of the family Plataspidae. Considering that gut symbiotic communities are vulnerable to invasion of foreign microbes, gut symbiotic associations have been thought to be evolutionarily not stable. Stinkbugs of the family Acanthosomatidae harbor a bacterial symbiont in the midgut crypts, the lumen of which is completely sealed off from the midgut main tract, thereby retaining the symbiont in the isolated cryptic cavities. We investigated histological, ecological, phylogenetic, and genomic aspects of the unique gut symbiosis of the acanthosomatid stinkbugs. Results Phylogenetic analyses showed that the acanthosomatid symbionts constitute a distinct clade in the γ-Proteobacteria, whose sister groups are the obligate endocellular symbionts of aphids Buchnera and the obligate gut symbionts of plataspid stinkbugs Ishikawaella. In addition to the midgut crypts, the symbionts were located in a pair of peculiar lubricating organs associated with the female ovipositor, by which the symbionts are vertically transmitted via egg surface contamination. The symbionts were detected not from ovaries but from deposited eggs, and surface sterilization of eggs resulted in symbiont-free hatchlings. The symbiont-free insects suffered retarded growth, high mortality, and abnormal morphology, suggesting important biological roles of the symbiont for the host insects. The symbiont phylogeny was generally concordant with the host phylogeny, indicating host-symbiont co-speciation over evolutionary time despite the extracellular association. Meanwhile, some local host-symbiont phylogenetic discrepancies were found, suggesting occasional horizontal symbiont transfers across the host lineages. The symbionts exhibited AT-biased nucleotide composition, accelerated molecular evolution, and reduced genome size, as has been observed in obligate endocellular insect symbionts. Conclusion Comprehensive studies of the acanthosomatid bacterial symbiosis provide new insights into the genomic evolution of extracellular symbiotic bacteria: host-symbiont co-speciation and drastic genome reduction can occur not only in endocellular symbiotic associations but also in extracellular ones. We suggest that many more such cases might be discovered in future surveys. PMID:19146674

Evolutionary patchwork of an insecticidal toxin shared between plant-associated pseudomonads and the insect pathogens Photorhabdus and Xenorhabdus.

PubMed

Ruffner, Beat; Péchy-Tarr, Maria; Höfte, Monica; Bloemberg, Guido; Grunder, Jürg; Keel, Christoph; Maurhofer, Monika

2015-08-16

Root-colonizing fluorescent pseudomonads are known for their excellent abilities to protect plants against soil-borne fungal pathogens. Some of these bacteria produce an insecticidal toxin (Fit) suggesting that they may exploit insect hosts as a secondary niche. However, the ecological relevance of insect toxicity and the mechanisms driving the evolution of toxin production remain puzzling. Screening a large collection of plant-associated pseudomonads for insecticidal activity and presence of the Fit toxin revealed that Fit is highly indicative of insecticidal activity and predicts that Pseudomonas protegens and P. chlororaphis are exclusive Fit producers. A comparative evolutionary analysis of Fit toxin-producing Pseudomonas including the insect-pathogenic bacteria Photorhabdus and Xenorhadus, which produce the Fit related Mcf toxin, showed that fit genes are part of a dynamic genomic region with substantial presence/absence polymorphism and local variation in GC base composition. The patchy distribution and phylogenetic incongruence of fit genes indicate that the Fit cluster evolved via horizontal transfer, followed by functional integration of vertically transmitted genes, generating a unique Pseudomonas-specific insect toxin cluster. Our findings suggest that multiple independent evolutionary events led to formation of at least three versions of the Mcf/Fit toxin highlighting the dynamic nature of insect toxin evolution.

A field test of the effect of spiked ivermectin concentrations on the biodiversity of coprophagous dung insects in Switzerland.

PubMed

Jochmann, Ralf; Lipkow, Erhard; Blanckenhorn, Wolf U

2016-08-01

Veterinary medical product residues can cause severe damage in the dung ecosystem. Depending on the manner of application and the time after treatment, the excreted concentration of a given pharmaceutical varies. The popular anthelmintic drug ivermectin can be applied to livestock in several different ways and is fecally excreted over a period of days to months after application. In a field experiment replicated in summer and autumn, the authors mixed 6 ivermectin concentrations plus a null control into fresh cow dung to assess the reaction of the dung insect community. Taxon richness of the insect dung fauna emerging from the dung, but not Hill diversity ((1) D) or the total number of individuals (abundance), decreased as ivermectin concentration increased. Corresponding declines in the number of emerging insects were found for most larger brachyceran flies and hymenopteran parasitoids, but not for most smaller nematoceran flies or beetles (except Hydrophilidae). Parallel pitfall traps recovered all major dung organism groups that emerged from the experimental dung, although at times in vastly different numbers. Ivermectin generally did not change the attractiveness of dung: differences in emergence therefore reflect differences in survival of coprophagous offspring of colonizing insects. Because sample size was limited to 6 replicates, the authors generally recommend more than 10 (seasonal) replicates and also testing higher concentrations than used in the present study as positive controls in future studies. Results accord with parallel experiments in which the substance was applied and passed through the cow's digestive system. In principle, therefore, the authors' experimental design is suitable for such higher-tier field tests of the response of the entire dung community to pharmaceutical residues, at least for ivermectin. Environ Toxicol Chem 2016;35:1947-1952. © 2015 SETAC. © 2015 SETAC.

Context-dependency of arbuscular mycorrhizal fungi on plant-insect interactions in an agroecosystem

PubMed Central

Barber, Nicholas A.; Kiers, E. Toby; Hazzard, Ruth V.; Adler, Lynn S.

2013-01-01

Plants interact with a variety of other community members that have the potential to indirectly influence each other through a shared host plant. Arbuscular mycorrhizal fungi (AMF) are generally considered plant mutualists because of their generally positive effects on plant nutrient status and growth. AMF may also have important indirect effects on plants by altering interactions with other community members. By influencing plant traits, AMF can modify aboveground interactions with both mutualists, such as pollinators, and antagonists, such as herbivores. Because herbivory and pollination can dramatically influence plant fitness, comprehensive assessment of plant–AMF interactions should include these indirect effects. To determine how AMF affect plant–insect interactions, we grew Cucumis sativus (Cucurbitaceae) under five AMF inoculum treatments and control. We measured plant growth, floral production, flower size, and foliar nutrient content of half the plants, and transferred the other half to a field setting to measure pollinator and herbivore preference of wild insects. Mycorrhizal treatment had no effect on plant biomass or floral traits but significantly affected leaf nutrients, pollinator behavior, and herbivore attack. Although total pollinator visitation did not vary with AMF treatment, pollinators exhibited taxon-specific responses, with honey bees, bumble bees, and Lepidoptera all responding differently to AMF treatments. Flower number and size were unaffected by treatments, suggesting that differences in pollinator preference were driven by other floral traits. Mycorrhizae influenced leaf K and Na, but these differences in leaf nutrients did not correspond to variation in herbivore attack. Overall, we found that AMF indirectly influence both antagonistic and mutualistic insects, but impacts depend on the identity of both the fungal partner and the interacting insect, underscoring the context-dependency of plant–AMF interactions. PMID:24046771

Instar- and host-associated differentiation of bacterial communities in the Mediterranean fruit fly Ceratitis capitata

PubMed Central

Campolo, Orlando; Medina, Raul F.; Palmeri, Vincenzo

2018-01-01

Microorganisms are acknowledged for their role in shaping insects’ evolution, life history and ecology. Previous studies have shown that microbial communities harbored within insects vary through ontogenetic development and among insects feeding on different host-plant species. In this study, we characterized the bacterial microbiota of the highly polyphagous Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), at different instars and when feeding on different host-plant species. Our results show that the bacterial microbiota hosted within the Mediterranean fruit fly differs among instars and host-plant species. Most of the bacteria harbored by the Mediterranean fruit fly belong to the phylum Proteobacteria, including genera of Alphaproteobacteria such as Acetobacter and Gluconobacter; Betaprotobacteria such as Burkholderia and Gammaproteobacteria such as Pseudomonas. PMID:29518170

An evaluation of lipid metabolism in the insect trypanosomatid Herpetomonas muscarum uncovers a pathway for the uptake of extracellular insect lipoproteins.

PubMed

Kluck, George; Régis, Karla C; De Cicco, Nuccia N T; Silva-Cardoso, Lívia; Pereira, Miria G; Fampa, Patrícia; Chagas-Lima, Alessandra C; Romeiro, Alexandre; Cunha-Silva, Narcisa L; Atella, Georgia C

2018-04-01

Lipid uptake and metabolism by trypanosomatid parasites from vertebrate host blood have been well established in the literature. However, there is a lack of knowledge regarding the same aspects concerning the parasites that cross the hemolymph of their invertebrate hosts. We have investigated the lipid composition and metabolism of the insect trypanosomatid Herpetomonas muscarum by 3 H- palmitic acid and phosphate ( 32 Pi) and the parasite interaction with Lipophorin (Lp) the main lipid carrying protein of insect hemolymph. Gas chromatography-mass spectrometry (GC-MS) analyses were used to identify the fatty acids and sterols composition of H.muscarum. Furthermore, we investigated the Lp binding site in the plasma membrane of parasite by Immunolocalization. We showed that H. muscarum incorporated 3H-palmitic acid and inorganic phosphate (32Pi) which were readily used as precursor molecules of lipid biosynthetic pathways. Furthermore, H. muscarum was able to take up both protein and lipid moieties of Lp which could be used as nutrient sources. Moreover, we have also demonstrated for the first time the presence of a Lp binding site in the membrane of a parasite. Such results point out the role of describing the metabolic pathways of trypanosomatids in order to provide a better understanding of parasite-host interaction peculiarities. Such studies may enhance the potential form the identification of novel chemotherapeutic targets in harmful parasites. Copyright © 2017 Elsevier B.V. All rights reserved.

Diversity of arthropod community in transgenic poplar-cotton ecosystems.

PubMed

Zhang, D J; Lu, Z Y; Liu, J X; Li, C L; Yang, M S

2015-12-02

Poplar-cotton agro-ecosystems are the main agricultural planting modes of plain cotton fields in China. Here, we performed a systematic survey of the diversity and population of arthropod communities in four different combination of poplar-cotton eco-systems, including I) non-transgenic poplar and non-transgenic cotton fields; II) non-transgenic poplar and transgenic cotton fields [Bacillus thuringiensis (Bt) cotton]; III) Bt transgenic poplar (high insect resistant strain Pb29) and non-transgenic cotton; and IV) transgenic poplar and transgenic cotton fields, over a period of 3 years. Based on the statistical methods used to investigate community ecology, the effects of transgenic ecosystems on the whole structure of the arthropod community, on the structure of arthropods in the nutritive layer, and on the similarity of arthropod communities were evaluated. The main results were as follows: the transgenic poplar-cotton ecosystem has a stronger inhibitory effect on insect pests and has no impact on the structure of the arthropod community, and therefore, maintains the diversity of the arthropod community. The character index of the community indicated that the structure of the arthropod community of the transgenic poplar-cotton ecosystem was better than that of the poplar-cotton ecosystem, and that system IV had the best structure. As for the abundance of nutritional classes, the transgenic poplar-cotton ecosystem was also better than that of the non-transgenic poplar-cotton ecosystem. The cluster analysis and similarity of arthropod communities between the four different transgenic poplar-cotton ecosystems illustrated that the structure of the arthropod community excelled in the small sample of the transgenic poplar-cotton ecosystems.

Composition and Longitudinal Patterns of Aquatic Insect Emergence in Small Rivers of Palawan Island, the Philippines

NASA Astrophysics Data System (ADS)

Freitag, Hendrik

2004-09-01

This study presents the first emergence trap samples from streams in the Philippines and Greater Sunda. Aquatic insect emergence from two small rivers and longitudinal patterns including estuaries are compared. A decline of total emergence towards estuaries was observed, affecting all major orders. Diptera, namely Chironomidae, dominated all sites. High abundances in Ceratopogonidae, Odonata, and Coleoptera were found, compared to other emergence studies from tropical and temperate latitudes. Ephemeroptera displayed a highly variable contribution to the emergence from Palawan as well as in other comparative studies either supported by the appropriate conditions for certain functional groups or limited by environmental variables such as pH. Trichoptera are likely to tolerate a wider range of environmental conditions and they are consequently able to fill further niches where Ephemeroptera are under-represented. Except for scarce abundances of Plecoptera observed in this and other studies from the tropics, no substantial differences in emergence composition at order level existed between temperate and tropical rivers, however, with a remarkable local variation. Components of riparian and non-aquatic insects and non-emergent fauna contributing to the collections are discussed based on trap features. (

Bacterial diversity of the American sand fly Lutzomyia intermedia using high-throughput metagenomic sequencing.

PubMed

Monteiro, Carolina Cunha; Villegas, Luis Eduardo Martinez; Campolina, Thais Bonifácio; Pires, Ana Clara Machado Araújo; Miranda, Jose Carlos; Pimenta, Paulo Filemon Paolucci; Secundino, Nagila Francinete Costa

2016-08-31

Parasites of the genus Leishmania cause a broad spectrum of diseases, collectively known as leishmaniasis, in humans worldwide. American cutaneous leishmaniasis is a neglected disease transmitted by sand fly vectors including Lutzomyia intermedia, a proven vector. The female sand fly can acquire or deliver Leishmania spp. parasites while feeding on a blood meal, which is required for nutrition, egg development and survival. The microbiota composition and abundance varies by food source, life stages and physiological conditions. The sand fly microbiota can affect parasite life-cycle in the vector. We performed a metagenomic analysis for microbiota composition and abundance in Lu. intermedia, from an endemic area in Brazil. The adult insects were collected using CDC light traps, morphologically identified, carefully sterilized, dissected under a microscope and the females separated into groups according to their physiological condition: (i) absence of blood meal (unfed = UN); (ii) presence of blood meal (blood-fed = BF); and (iii) presence of developed ovaries (gravid = GR). Then, they were processed for metagenomics with Illumina Hiseq Sequencing in order to be sequence analyzed and to obtain the taxonomic profiles of the microbiota. Bacterial metagenomic analysis revealed differences in microbiota composition based upon the distinct physiological stages of the adult insect. Sequence identification revealed two phyla (Proteobacteria and Actinobacteria), 11 families and 15 genera; 87 % of the bacteria were Gram-negative, while only one family and two genera were identified as Gram-positive. The genera Ochrobactrum, Bradyrhizobium and Pseudomonas were found across all of the groups. The metagenomic analysis revealed that the microbiota of the Lu. intermedia female sand flies are distinct under specific physiological conditions and consist of 15 bacterial genera. The Ochrobactrum, Bradyrhizobium and Pseudomonas were the common genera. Our results detailing the constituents of Lu. intermedia native microbiota contribute to the knowledge regarding the bacterial community in an important sand fly vector and allow for further studies to better understand how the microbiota interacts with vectors of human parasites and to develop tools for biological control.

Bacterial Community and PHB-Accumulating Bacteria Associated with the Wall and Specialized Niches of the Hindgut of the Forest Cockchafer (Melolontha hippocastani).

PubMed

Alonso-Pernas, Pol; Arias-Cordero, Erika; Novoselov, Alexey; Ebert, Christina; Rybak, Jürgen; Kaltenpoth, Martin; Westermann, Martin; Neugebauer, Ute; Boland, Wilhelm

2017-01-01

A characterization of the bacterial community of the hindgut wall of two larval and the adult stages of the forest cockchafer ( Melolontha hippocastani ) was carried out using amplicon sequencing of the 16S rRNA gene fragment. We found that, in second-instar larvae, Caulobacteraceae and Pseudomonadaceae showed the highest relative abundances, while in third-instar larvae, the dominant families were Porphyromonadaceae and Bacteroidales-related. In adults, an increase of the relative abundance of Bacteroidetes, Proteobacteria (γ- and δ- classes) and the family Enterococcaceae (Firmicutes) was observed. This suggests that the composition of the hindgut wall community may depend on the insect's life stage. Additionally, specialized bacterial niches hitherto very poorly described in the literature were spotted at both sides of the distal part of the hindgut chamber. We named these structures "pockets." Amplicon sequencing of the 16S rRNA gene fragment revealed that the pockets contained a different bacterial community than the surrounding hindgut wall, dominated by Alcaligenaceae and Micrococcaceae-related families. Poly-β-hydroxybutyrate (PHB) accumulation in the pocket was suggested in isolated Achromobacter sp. by Nile Blue staining, and confirmed by gas chromatography-mass spectrometry analysis (GC-MS) on cultured bacterial mass and whole pocket tissue. Raman micro-spectroscopy allowed to visualize the spatial distribution of PHB accumulating bacteria within the pocket tissue. The presence of this polymer might play a role in the colonization of these specialized niches.

Seasonal Abundance and Natural Inoculativity of Insect Vectors of Xylella fastidiosa in Oklahoma Tree Nurseries and Vineyards.

PubMed

Overall, Lisa M; Rebek, Eric J

2015-12-01

Xylella fastidiosa is the causative agent of diseases of perennial plants including peach, plum, elm, oak, pecan, and grape. This bacterial pathogen is transmitted by xylem-feeding insects. In recent years, Pierce's disease of grape has been detected in 10 counties in central and northeastern Oklahoma, prompting further investigation of the disease epidemiology in this state. We surveyed vineyards and tree nurseries in Oklahoma for potential insect vectors to determine species composition, infectivity, and natural inoculativity of commonly captured insect vectors. Yellow sticky cards were used to sample insect fauna at each location. Insects were removed from sticky cards and screened for X. fastidiosa using immunocapture-PCR to determine their infectivity. A second objective was to test the natural inoculativity of insect vectors that are found in vineyards. Graphocephala versuta (Say), Graphocephala coccinea (Forster), Paraulacizes irrorata (F.), Oncometopia orbona (F.), Cuerna costalis (F.), and Entylia carinata Germar were collected from vineyards and taken back to the lab to determine their natural inoculativity. Immunocapture-PCR was used to test plant and insect samples for presence of X. fastidiosa. The three most frequently captured species from vineyards and tree nurseries were G. versuta, Clastoptera xanthocephala Germar, and O. orbona. Of those insects screened for X. fastidiosa, 2.4% tested positive for the bacterium. Field-collected G. versuta were inoculative to both ragweed and alfalfa. Following a 7-d inoculation access period, a higher percentage of alfalfa became infected than ragweed. Results from this study provide insight into the epidemiology of X. fastidiosa in Oklahoma. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Direct and indirect effects of light pollution on the performance of an herbivorous insect.

PubMed

Grenis, Kylee; Murphy, Shannon M

2018-02-09

Light pollution is a global disturbance with resounding impacts on a wide variety of organisms, but our understanding of these impacts is restricted to relatively few higher vertebrate species. We tested the direct effects of light pollution on herbivore performance as well as indirect effects mediated by host plant quality. We found that artificial light from streetlights alters plant toughness. Additionally, we found evidence of both direct and indirect effects of light pollution on the performance of an herbivorous insect, which indicates that streetlights can have cascading impacts on multiple trophic levels. Our novel findings suggest that light pollution can alter plant-insect interactions and thus may have important community-wide consequences. © 2018 Institute of Zoology, Chinese Academy of Sciences.

Antagonistic interactions between garden yeasts and microfungal garden pathogens of leaf-cutting ants.

PubMed

Rodrigues, Andre; Cable, Rachel N; Mueller, Ulrich G; Bacci, Maurício; Pagnocca, Fernando C

2009-10-01

We investigate the diversity of yeasts isolated in gardens of the leafcutter ant Atta texana. Repeated sampling of gardens from four nests over a 1-year time period showed that gardens contain a diverse assemblage of yeasts. The yeast community in gardens consisted mostly of yeasts associated with plants or soil, but community composition changed between sampling periods. In order to understand the potential disease-suppressing roles of the garden yeasts, we screened isolates for antagonistic effects against known microfungal garden contaminants. In vitro assays revealed that yeasts inhibited the mycelial growth of two strains of Escovopsis (a specialized attine garden parasite), Syncephalastrum racemosum (a fungus often growing in gardens of leafcutter lab nests), and the insect pathogen Beauveria bassiana. These garden yeasts add to the growing list of disease-suppressing microbes in attine nests that may contribute synergistically, together with actinomycetes and Burkholderia bacteria, to protect the gardens and the ants against diseases. Additionally, we suggest that garden immunity against problem fungi may therefore derive not only from the presence of disease-suppressing Pseudonocardia actinomycetes, but from an enrichment of multiple disease-suppressing microorganisms in the garden matrix.

Macrofaunal Succession and Community Structure in Salicornia Marshes of Southern California

NASA Astrophysics Data System (ADS)

Talley, T. S.; Levin, L. A.

1999-11-01

Lack of basic understanding of ecosystem structure and function forms a major impediment to successful conservation of coastal ecosystems. This paper provides a description of the fauna and examines faunal succession in Salicornia -vegetated sediments of southern California. Environmental attributes (vegetation and sediment properties) and macrofaunal (animals ≥0·3 mm) community structure were examined in sediments of five natural, southern California Salicornia spp. marshes (Tijuana Estuary, San Diego Bay, Mission Bay, Upper Newport Bay and Anaheim Bay) and in created Salicornia marshes 16 months to 10 years in age, located within four of the bays. Oligochaetes and insects were the dominant taxa in both natural (71 to 98% of total fauna) and created (91 to 97%) marshes. In San Diego, Newport and Anaheim Bays, macrofaunal densities were generally higher in the created marshes (88 000 to 290 000 ind m -2) than in their natural counterparts (26 000 to 50 000 ind m -2). In the youngest system, Mission Bay, the reverse was true (natural: 113 000 vs created: 28 000 ind m -2). Similar species numbers were recorded from the created and adjacent natural marshes. Insects, especially chironomids, dolichopodids, and heleids, as well as the naidid oligochaete, Paranais litoralis, characterize early successional stages. Enchytraeid and tubificid oligochaetes reflect later succession evident in natural and older created marshes. Sediment organic matter (both combustible and below-ground plant biomass) was the environmental variable most commonly associated with densities of various macrofaunal taxa. These relationships were generally negative in the natural marshes and positive in the created marshes. Within-bay comparisons of macrofauna from natural Salicornia- vs Spartina -vegetated habitat in San Diego and Mission Bays revealed lower macrofaunal density (San Diego Bay only), proportionally fewer oligochaetes and more insects, and no differences in species richness in the Salicornia habitat. The oldest created Salicornia marsh (San Diego Bay) exhibited an assemblage intermediate in composition between those of the natural Salicornia- and Spartina- vegetated marshes. These results suggest: (a) faunal recovery following Salicornia marsh creation can require 10 or more years, (b) high macrofaunal variability among bays requires marsh creation reference site selection from within the same bay, and (c) Spartina -based research should not be used for Salicornia marsh management decisions.

Geographic variation in bacterial communities associated with the red turpentine beetle (Coleoptera: Curculionidae)

Treesearch

Aaron S. Adams; Sandye M. Adams; Cameron R. Currie; Nancy E. Gillette; Kenneth F. Raffa

2010-01-01

Bacterial communities are known to play important roles in insect life histories, yet their consistency or variation across populations is poorly understood. Bacteria associated with the bark beetle Dendroctonus valens LeConte from eight populations, ranging from Wisconsin to Oregon, were evaluated and compared. We used the culture-independent technique of denaturing...

The i5k Workspace@NAL – enabling genomic data access, visualization, and curation for the i5k community

USDA-ARS?s Scientific Manuscript database

The 5,000 arthropod genomes initiative (i5k) has tasked itself with coordinating the sequencing of 5,000 insect or related arthropod genomes. The resulting influx of data, mostly from small research groups or communities with little bioinformatics experience, will require visualization, disseminatio...

Insectivory versus piscivory in Black Terns: Implications for food provisioning and growth of chicks

USGS Publications Warehouse

Gilbert, A.T.; Servello, F.A.

2005-01-01

The Black Tern (Chlidonias niger) is known for insectivory in their breeding range, but they are piscivorous in winter and feed some fish to chicks. Fish have potentially high value for chick provisioning because of their larger mass, but the relative value of fish and insect diets for chick growth is unknown. In 1999-2000, we documented use of fish and insects for provisioning chicks at four Black Tern colonies in Maine and examined chick growth rates at two colonies (Douglas Pond and Carlton Pond) that differed in fish and insect use. Deliveries of fish and insects to broods were documented using video cameras and observations from blinds, while concurrently measuring chick growth in nest enclosures. Fish use was substantial (>25% of deliveries) at three of four colonies. Fish comprised 29% of items and 56% of metabolizable energy delivered to chicks at Douglas Pond compared to 13% of items and 22% of metabolizeable energy at Carlton Pond. Food delivery rate was inversely related to the proportion of large fish. In brood diets at Douglas and Carlton Ponds and increased with brood age at Carlton Pond only, apparently due to high insect use. Chick growth rate did not vary with respect to fish and insect composition of diets. It is concluded that adults were able to raise chicks through age 12 d at comparable growth rates with insect-or fish-dominated diets. Use of fish may be more energy efficient for adults, and the capability to use both fish and insects may reduce potential variability in food availability during the breeding season.

Bull Trout Forage Investigations in Beulah Reservoir, Oregon - Annual Report for 2006

USGS Publications Warehouse

Rose, Brien P.; Mesa, Mathew G.

2009-01-01

Beulah Reservoir on the north fork of the Malheur River in northeastern Oregon provides irrigation water to nearby farms and ranches and supports an adfluvial population of bull trout (Salvelinus confluentus), which are listed as threatened under the Endangered Species Act. Water management in Beulah Reservoir results in seasonal and annual fluctuations of water volume that may affect forage availability for bull trout. Because no minimum pool requirements currently exist, the reservoir is occasionally reduced to run-of-river levels, which may decimate forage fish populations and ultimately affect bull trout. We sampled fish and aquatic insects in Beulah Reservoir in the spring, before the annual drawdown of 2006, and afterward, in the late fall. We also collected samples 1.5 years after the reservoir was dewatered for three consecutive summers. Overall, the moderate drawdown of 2006 (32 percent of full pool) did not drastically alter the fish community in Beulah Reservoir. We did document, however, decreases in abundance and sizes of chironomids in areas of the reservoir that were frequently dewatered, increased catch rates of fish with gillnets, and decreases in population estimates for smaller fishes after drawdown. In 2006, after the dewaterings of 2002-04, species composition was similar to that prior to the dewaterings, but the size distributions of most species were biased toward small juvenile or subyearling fishes and larger fishes were rare. Our results indicate that repeated reservoir drawdown reduces aquatic insect forage for bull trout and probably affects forage fish populations at least temporarily. The high catch rates of juvenile fishes 1.5 years after consecutive dewaterings suggests good reproductive success for any remaining adult fish, and shows that the fish community in Beulah Reservoir is resilient to such disturbances. There is, however, a period of time after serious drawdowns before significant numbers of juvenile fishes start to appear in the reservoir. Because Beulah Reservoir experiences a wide variety of drawdown scenarios in consecutive years, the forage fish community may never reach a state of equilibrium.

Linking agricultural practices, mycorrhizal fungi, and traits mediating plant-insect interactions.

PubMed

Barber, Nicholas A; Kiers, E Toby; Theis, Nina; Hazzard, Ruth V; Adler, Lynn S

2013-10-01

Agricultural management has profound effects on soil communities. Activities such as fertilizer inputs can modify the composition of arbuscular mycorrhizal fungi (AMF) communities, which form important symbioses with the roots of most crop plants. Intensive conventional agricultural management may select for less mutualistic AMF with reduced benefits to host plants compared to organic management, but these differences are poorly understood. AMF are generally evaluated based on their direct growth effects on plants. However, mycorrhizal colonization also may alter plant traits such as tissue nutrients, defensive chemistry, or floral traits, which mediate important plant-insect interactions like herbivory and pollination. To determine the effect of AMF from different farming practices on plant performance and traits that putatively mediate species interactions, we performed a greenhouse study by inoculating Cucumis sativus (cucumber, Cucurbitaceae) with AMF from conventional farms, organic farms, and a commercial AMF inoculum. We measured growth and a suite of plant traits hypothesized to be important predictors of herbivore resistance and pollinator attraction. Several leaf and root traits and flower production were significantly affected by AMF inoculum. Both conventional and organic AMF reduced leaf P content but increased Na content compared to control and commercial AMF. Leaf defenses were unaffected by AMF treatments, but conventional AMF increased root cucurbitacin C, the primary defensive chemical of C. sativus, compared to organic AMF. These effects may have important consequences for herbivore preference and population dynamics. AMF from both organic and conventional farms decreased flower production relative to commercial and control treatments, which may reduce pollinator attraction and plant reproduction. AMF from both farm types also reduced seed germination, but effects on plant growth were limited. Our results suggest that studies only considering AMF effects on growth may overlook changes in plant traits that have the potential to influence interactions, and hence yield, on farms. Given the effects of AMF on plant traits documented here, and the great importance of both herbivores and pollinators to wild and cultivated plants, we advocate for comprehensive assessments of mycorrhizal effects in complex community contexts, with the aim of incorporating multispecies interactions both above and below the soil surface.

Protein quality of insects as potential ingredients for dog and cat foods.

PubMed

Bosch, Guido; Zhang, Sheng; Oonincx, Dennis G A B; Hendriks, Wouter H

2014-01-01

Insects have been proposed as a high-quality, efficient and sustainable dietary protein source. The present study evaluated the protein quality of a selection of insect species. Insect substrates were housefly pupae, adult house cricket, yellow mealworm larvae, lesser mealworm larvae, Morio worm larvae, black soldier fly larvae and pupae, six spot roach, death's head cockroach and Argentinean cockroach. Reference substrates were poultry meat meal, fish meal and soyabean meal. Substrates were analysed for DM, N, crude fat, ash and amino acid (AA) contents and for in vitro digestibility of organic matter (OM) and N. The nutrient composition, AA scores as well as in vitro OM and N digestibility varied considerably between insect substrates. For the AA score, the first limiting AA for most substrates was the combined requirement for Met and Cys. The pupae of the housefly and black soldier fly were high in protein and had high AA scores but were less digestible than other insect substrates. The protein content and AA score of house crickets were high and similar to that of fish meal; however, in vitro N digestibility was higher. The cockroaches were relatively high in protein but the indispensable AA contents, AA scores and the in vitro digestibility values were relatively low. In addition to the indices of protein quality, other aspects such as efficiency of conversion of organic side streams, feasibility of mass-production, product safety and pet owner perception are important for future dog and cat food application of insects as alternative protein source.

First survey of forensically important insects from human corpses in Shiraz, Iran.

PubMed

Moemenbellah-Fard, Mohammad D; Keshavarzi, Davood; Fereidooni, Mehran; Soltani, Aboozar

2018-02-01

The presence of insects on human cadavers has potential judicial value in medicolegal cases. This research emphasized the important role of insects in postmortem decomposition. It was conducted to investigate the composition and abundance of insects from human corpses during autopsies in legal medicine. It was implemented in the city of Shiraz, south Iran. Insects associated with human corpses were carefully collected and put into labelled vials. They were then identified using valid taxonomic keys. Fifteen outdoor (67%) and indoor discovered cadavers were examined. All but one was covered at the time of discovery. From these several species of entomofauna played important roles in the minimum postmortem interval (minPMI) estimate. Insects included the orders of Diptera and Coleoptera. Overall, 14 different species of arthropods were identified. Within Diptera, 2 families of Sarcophagidae and Calliphoridae were present in 73% of the cases with Calliphora vicina Robineau-Desvoidy and Chrysomya albiceps Wiedemann accounting for about half of the cases. The latter family members, Calliphoridae, were more frequently (52%) collected in autumn and winter. Only 4/15 outdoor cadavers had beetles. Four species of Coleopterans; namely Dermestes frischii Kugelann, Nitidula flavomaculata Rossi, Creophilus maxillosus Linnaeus and Saprinus chalcites Illiger; were recorded for the first time from 3 corpses in Iran. The presence and diversity of different insects on human corpses could contribute to the advancement of forensic entomology knowledge and the refined estimates of minPMI in medicolegal cases. Copyright © 2017. Published by Elsevier Ltd.

The Evolution of Stomach Acidity and Its Relevance to the Human Microbiome

PubMed Central

Beasley, DeAnna E.; Koltz, Amanda M.; Lambert, Joanna E.; Fierer, Noah; Dunn, Rob R.

2015-01-01

Gastric acidity is likely a key factor shaping the diversity and composition of microbial communities found in the vertebrate gut. We conducted a systematic review to test the hypothesis that a key role of the vertebrate stomach is to maintain the gut microbial community by filtering out novel microbial taxa before they pass into the intestines. We propose that species feeding either on carrion or on organisms that are close phylogenetic relatives should require the most restrictive filter (measured as high stomach acidity) as protection from foreign microbes. Conversely, species feeding on a lower trophic level or on food that is distantly related to them (e.g. herbivores) should require the least restrictive filter, as the risk of pathogen exposure is lower. Comparisons of stomach acidity across trophic groups in mammal and bird taxa show that scavengers and carnivores have significantly higher stomach acidities compared to herbivores or carnivores feeding on phylogenetically distant prey such as insects or fish. In addition, we find when stomach acidity varies within species either naturally (with age) or in treatments such as bariatric surgery, the effects on gut bacterial pathogens and communities are in line with our hypothesis that the stomach acts as an ecological filter. Together these results highlight the importance of including measurements of gastric pH when investigating gut microbial dynamics within and across species. PMID:26222383

The Evolution of Stomach Acidity and Its Relevance to the Human Microbiome.

PubMed

Beasley, DeAnna E; Koltz, Amanda M; Lambert, Joanna E; Fierer, Noah; Dunn, Rob R

2015-01-01

Gastric acidity is likely a key factor shaping the diversity and composition of microbial communities found in the vertebrate gut. We conducted a systematic review to test the hypothesis that a key role of the vertebrate stomach is to maintain the gut microbial community by filtering out novel microbial taxa before they pass into the intestines. We propose that species feeding either on carrion or on organisms that are close phylogenetic relatives should require the most restrictive filter (measured as high stomach acidity) as protection from foreign microbes. Conversely, species feeding on a lower trophic level or on food that is distantly related to them (e.g. herbivores) should require the least restrictive filter, as the risk of pathogen exposure is lower. Comparisons of stomach acidity across trophic groups in mammal and bird taxa show that scavengers and carnivores have significantly higher stomach acidities compared to herbivores or carnivores feeding on phylogenetically distant prey such as insects or fish. In addition, we find when stomach acidity varies within species either naturally (with age) or in treatments such as bariatric surgery, the effects on gut bacterial pathogens and communities are in line with our hypothesis that the stomach acts as an ecological filter. Together these results highlight the importance of including measurements of gastric pH when investigating gut microbial dynamics within and across species.

Temporal Statistics of Natural Image Sequences Generated by Movements with Insect Flight Characteristics

PubMed Central

Schwegmann, Alexander; Lindemann, Jens Peter; Egelhaaf, Martin

2014-01-01

Many flying insects, such as flies, wasps and bees, pursue a saccadic flight and gaze strategy. This behavioral strategy is thought to separate the translational and rotational components of self-motion and, thereby, to reduce the computational efforts to extract information about the environment from the retinal image flow. Because of the distinguishing dynamic features of this active flight and gaze strategy of insects, the present study analyzes systematically the spatiotemporal statistics of image sequences generated during saccades and intersaccadic intervals in cluttered natural environments. We show that, in general, rotational movements with saccade-like dynamics elicit fluctuations and overall changes in brightness, contrast and spatial frequency of up to two orders of magnitude larger than translational movements at velocities that are characteristic of insects. Distinct changes in image parameters during translations are only caused by nearby objects. Image analysis based on larger patches in the visual field reveals smaller fluctuations in brightness and spatial frequency composition compared to small patches. The temporal structure and extent of these changes in image parameters define the temporal constraints imposed on signal processing performed by the insect visual system under behavioral conditions in natural environments. PMID:25340761

Fungal Community Associated with Dactylopius (Hemiptera: Coccoidea: Dactylopiidae) and Its Role in Uric Acid Metabolism

PubMed Central

Vera-Ponce de León, Arturo; Sanchez-Flores, Alejandro; Rosenblueth, Mónica; Martínez-Romero, Esperanza

2016-01-01

We studied fungal species associated with the carmine cochineal Dactylopius coccus and other non-domesticated Dactylopius species using culture-dependent and -independent methods. Thirty seven fungi were isolated in various culture media from insect males and females from different developmental stages and Dactylopius species. 26S rRNA genes and ITS sequences, from cultured fungal isolates revealed different species of Cryptococcus, Rhodotorula, Debaryomyces, Trametes, and Penicillium, which are genera newly associated with Dactylopius. Uric acid (UA) and uricase activity were detected in tissues extracts from different insect developmental stages. However, accumulation of high UA levels and low uricase activities were found only after antifungal treatments, suggesting an important role of fungal species in its metabolism. Additionally, uricolytic fungal isolates were identified and characterized that presumably are involved in nitrogen recycling metabolism. After metagenomic analyses from D. coccus gut and hemolymph DNA and from two published data sets, we confirmed the presence of fungal genes involved in UA catabolism, suggesting that fungi help in the nitrogen recycling process in Dactylopius by uricolysis. All these results show the importance of fungal communities in scale insects such as Dactylopius. PMID:27446001

Needle oils of three pine species and species hybrids

Treesearch

Robert Z. Callaham

1956-01-01

The composition and characteristics of the needle oils of western pines may provide criteria for distinguishing pine hybrids and may help explain why some needle-feeding insects select certain pine species as hosts.

Macroinvertebrate communities evaluated prior to and following a channel restoration project in Silver Creek, Blaine County, Idaho, 2001-16

USGS Publications Warehouse

MacCoy, Dorene E.; Short, Terry M.

2017-11-22

The U.S. Geological Survey, in cooperation with Blaine County and The Nature Conservancy, evaluated the status of macroinvertebrate communities prior to and following a channel restoration project in Silver Creek, Blaine County, Idaho. The objective of the evaluation was to determine whether 2014 remediation efforts to restore natural channel conditions in an impounded area of Silver Creek caused declines in local macroinvertebrate communities. Starting in 2001 and ending in 2016, macroinvertebrates were sampled every 3 years at two long-term trend sites and sampled seasonally (spring, summer, and autumn) in 2013, 2015, and 2016 at seven synoptic sites. Trend-site communities were collected from natural stream-bottom substrates to represent locally established macroinvertebrate assemblages. Synoptic site communities were sampled using artificial (multi-plate) substrates to represent recently colonized (4–6 weeks) assemblages. Statistical summaries of spatial and temporal patterns in macroinvertebrate taxonomic composition at both trend and synoptic sites were completed.The potential effect of the restoration project on resident macroinvertebrate populations was determined by comparing the following community assemblage metrics:Total taxonomic richness (taxa richness);Total macroinvertebrate abundance (total abundance);Ephemeroptera, Plecoptera, Trichoptera (EPT) richness;EPT abundance;Simpson’s diversity; andSimpson’s evenness for periods prior to and following restoration.A significant decrease in one or more metric values in the period following stream channel restoration was the basis for determining impairment to the macroinvertebrate communities in Silver Creek.Comparison of pre-restoration (2001–13) and post‑restoration (2016) macroinvertebrate community composition at trend sites determined that no significant decreases occurred in any metric parameter for communities sampled in 2016. Taxa and EPT richness of colonized assemblages at synoptic sites increased significantly from pre-restoration in 2013 to post-restoration in 2015 and 2016. Similarly, total and EPT abundances at synoptic sites showed non-significant increases from 2013 to 2015 and 2016. Significant seasonal differences in macroinvertebrate assemblages were apparent at synoptic site locations and likely reflected typical life-history patterns of increased insect emergence and development in the late spring and early summer months. Taxa and EPT richness were each significantly higher in spring and summer than in autumn, and total abundances were significantly higher in spring than in summer and autumn. No significant differences in community diversity or evenness of colonized communities were noted at synoptic site locations between pre- and post-restoration years or among seasons. Select community-metric results from the trend- and synoptic‑site sampling indicated that the Silver Creek restoration effort in 2014 did not result in a significant decline in resident macroinvertebrate communities.

Effects of below-ground insects, mycorrhizal fungi and soil fertility on the establishment of Vicia in grassland communities.

PubMed

Ganade, G; Brown, V K

1997-02-01

 The effects of, and interactions between, insect root feeders, vesicular-arbuscular mycorrhizal fungi and soil fertility on the establishment, growth and reproduction of Vicia sativa and V. hirsuta (Fabaceae) were investigated in an early-successional grassland community. Seeds of both species were sown into plots where soil insecticide (Dursban 5G), soil fungicide (Rovral) and soil fertiliser (NPK) were applied in a factorial randomised block design. Fertiliser addition reduced growth, longevity and reproduction of both Vicia species, due to the commonly recorded increase in the competitive advantage of the non-nitrogen-fixing species when nitrogen is added to the plant community. However, in plots where fertiliser was not applied, a reduction in root feeders and mycorrhizal infection led to an increase in seedling establishment and fruit production of V. sativa, and to an increase in flower production for both Vicia species. The interaction between all three soil treatments explained much of the variation in growth and longevity of V. sativa. Plants grew larger and survived longer in plots where natural levels of mycorrhizal infection and root feeders were low compared with plots where all the treatments were applied. This suggests that, although soil nutrient availability was a strong determinant of the performance of these two leguminous species, at natural levels of soil fertility biotic factors acting in the soil, such as mycorrhizal fungi and soil-dwelling insects, were important in shaping the competitive interactions between the two Vicia species and the plant community. Our results indicate that non-additive interactions between ecological factors in the soil environment may strongly affect plant performance.

The rainy season increases the abundance and richness of the aquatic insect community in a Neotropical reservoir.

PubMed

Santana, H S; Silva, L C F; Pereira, C L; Simião-Ferreira, J; Angelini, R

2015-01-01

Alterations in aquatic systems and changes in water levels, whether due to rains or dam-mediated control can cause changes in community structure, forcing the community to readjust to the new environment. This study tested the hypothesis that there is an increase in the richness and abundance of aquatic insects during the rainy season in the Serra da Mesa Reservoir, with the premise that increasing the reservoir level provides greater external material input and habitat diversity, and, therefore, conditions that promote colonization by more species. We used the paired t test to test the differences in richness, beta diversity, and abundance, and a Non-metric Multidimensional Scaling (NMDS) was performed to identify patterns in the community under study. Additionally, Pearson correlations were analyzed between the richness, abundance, and beta diversity and the level of the reservoir. We collected 35,028 aquatic insect larvae (9,513 in dry period and 25,515 in the rainy season), predominantly of the Chironomidae family, followed by orders Ephemeroptera, Trichoptera, and Odonata. Among the 33 families collected, only 12 occurred in the dry season, while all occurred in the rainy season. These families are common in lentic environments, and the dominance of Chironomidae was associated with its fast colonization, their behavior of living at high densities and the great tolerance to low levels of oxygen in the environment. The hypothesis was confirmed, as the richness, beta diversity, and abundance were positively affected by the increase in water levels due to the rainy season, which most likely led to greater external material input, greater heterogeneity of habitat, and better conditions for colonization by several families.

Use of large-scale acoustic monitoring to assess anthropogenic pressures on Orthoptera communities.

PubMed

Penone, Caterina; Le Viol, Isabelle; Pellissier, Vincent; Julien, Jean-François; Bas, Yves; Kerbiriou, Christian

2013-10-01

Biodiversity monitoring at large spatial and temporal scales is greatly needed in the context of global changes. Although insects are a species-rich group and are important for ecosystem functioning, they have been largely neglected in conservation studies and policies, mainly due to technical and methodological constraints. Sound detection, a nondestructive method, is easily applied within a citizen-science framework and could be an interesting solution for insect monitoring. However, it has not yet been tested at a large scale. We assessed the value of a citizen-science program in which Orthoptera species (Tettigoniidae) were monitored acoustically along roads. We used Bayesian model-averaging analyses to test whether we could detect widely known patterns of anthropogenic effects on insects, such as the negative effects of urbanization or intensive agriculture on Orthoptera populations and communities. We also examined site-abundance correlations between years and estimated the biases in species detection to evaluate and improve the protocol. Urbanization and intensive agricultural landscapes negatively affected Orthoptera species richness, diversity, and abundance. This finding is consistent with results of previous studies of Orthoptera, vertebrates, carabids, and butterflies. The average mass of communities decreased as urbanization increased. The dispersal ability of communities increased as the percentage of agricultural land and, to a lesser extent, urban area increased. Despite changes in abundances over time, we found significant correlations between yearly abundances. We identified biases linked to the protocol (e.g., car speed or temperature) that can be accounted for ease in analyses. We argue that acoustic monitoring of Orthoptera along roads offers several advantages for assessing Orthoptera biodiversity at large spatial and temporal extents, particularly in a citizen science framework. © 2013 Society for Conservation Biology.

Solid Phase Micro-extraction (SPME) with In Situ Transesterification: An Easy Method for the Detection of Non-volatile Fatty Acid Derivatives on the Insect Cuticle.

PubMed

Kühbandner, Stephan; Ruther, Joachim

2015-06-01

Triacylglycerides (TAGs) and other non-volatile fatty acid derivatives (NFADs) occur in large amounts in the internal tissues of insects, but their presence on the insect cuticle is controversially discussed. Most studies investigating cuticular lipids of insects involve solvent extraction, which implies the risk of extracting lipids from internal tissues. Here, we present a new method that overcomes this problem. The method employs solid phase micro-extraction (SPME) to sample NFADs by rubbing the SPME fiber over the insect cuticle. Subsequently, the sampled NFADs are transesterified in situ with trimethyl sulfonium hydroxide (TMSH) into more volatile fatty acid methyl esters (FAMEs), which can be analyzed by standard GC/MS. We performed two types of control experiments to enable significant conclusions: (1) to rule out contamination of the GC/MS system with NFADs, and (2) to exclude the presence of free fatty acids on the insect cuticle, which would also furnish FAMEs after TMSH treatment, and thus might simulate the presence of NFADs. In combination with these two essential control experiments, the described SPME technique can be used to detect TAGs and/or other NFADs on the insect cuticle. We analyzed six insect species from four insect orders with our method and compared the results with conventional solvent extraction followed by ex situ transesterification. Several fatty acids typically found as constituents of TAGs were detected by the SPME method on the cuticle of all species analyzed. A comparison of the two methods revealed differences in the fatty acid compositions of the samples. Saturated fatty acids showed by trend higher relative abundances when sampled with the SPME method, while several minor FAMEs were detected only in the solvent extracts. Our study suggests that TAGs and maybe other NFADs are far more common on the insect cuticle than usually thought.

Evaluation of hazardous chemicals in edible insects and insect-based food intended for human consumption.

PubMed

Poma, Giulia; Cuykx, Matthias; Amato, Elvio; Calaprice, Chiara; Focant, Jean Francois; Covaci, Adrian

2017-02-01

Due to the rapid increase in world population, the waste of food and resources, and non-sustainable food production practices, the use of alternative food sources is currently strongly promoted. In this perspective, insects may represent a valuable alternative to main animal food sources due to their nutritional value and sustainable production. However, edible insects may be perceived as an unappealing food source and are indeed rarely consumed in developed countries. The food safety of edible insects can thus contribute to the process of acceptance of insects as an alternative food source, changing the perception of developed countries regarding entomophagy. In the present study, the levels of organic contaminants (i.e. flame retardants, PCBs, DDT, dioxin compounds, pesticides) and metals (As, Cd, Co, Cr, Cu, Ni, Pb, Sn, Zn) were investigated in composite samples of several species of edible insects (greater wax moth, migratory locust, mealworm beetle, buffalo worm) and four insect-based food items currently commercialized in Belgium. The organic chemical mass fractions were relatively low (PCBs: 27-2065 pg/g ww; OCPs: 46-368 pg/g ww; BFRs: up to 36 pg/g ww; PFRs 783-23800 pg/g ww; dioxin compounds: up to 0.25 pg WHO-TEQ/g ww) and were generally lower than those measured in common animal products. The untargeted screening analysis revealed the presence of vinyltoluene, tributylphosphate (present in 75% of the samples), and pirimiphos-methyl (identified in 50% of the samples). The levels of Cu and Zn in insects were similar to those measured in meat and fish in other studies, whereas As, Co, Cr, Pb, Sn levels were relatively low in all samples (<0.03 mg/kg ww). Our results support the possibility to consume these insect species with no additional hazards in comparison to the more commonly consumed animal products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Assessment of streamside management zones for conserving benthic macroinvertebrate communities following timber harvest in eastern Kentucky headwater catchments

Treesearch

Joshua Adkins; Christopher Barton; Scott Grubbs; Jeffrey Stringer; Randy Kolka

2016-01-01

Headwater streams generally comprise the majority of stream area in a watershed and can have a strong influence on downstream food webs. Our objective was to determine the effect of altering streamside management zone (SMZ) configurations on headwater aquatic insect communities. Timber harvests were implemented within six watersheds in eastern Kentucky. The SMZ...

Seasonal dynamics of microbial community composition and function in oak canopy and open grassland soils

USGS Publications Warehouse

Waldrop, M.P.; Firestone, M.K.

2006-01-01

Soil microbial communities are closely associated with aboveground plant communities, with multiple potential drivers of this relationship. Plants can affect available soil carbon, temperature, and water content, which each have the potential to affect microbial community composition and function. These same variables change seasonally, and thus plant control on microbial community composition may be modulated or overshadowed by annual climatic patterns. We examined microbial community composition, C cycling processes, and environmental data in California annual grassland soils from beneath oak canopies and in open grassland areas to distinguish factors controlling microbial community composition and function seasonally and in association with the two plant overstory communities. Every 3 months for up to 2 years, we monitored microbial community composition using phospholipid fatty acid (PLFA) analysis, microbial biomass, respiration rates, microbial enzyme activities, and the activity of microbial groups using isotope labeling of PLFA biomarkers (13C-PLFA) . Distinct microbial communities were associated with oak canopy soils and open grassland soils and microbial communities displayed seasonal patterns from year to year. The effects of plant species and seasonal climate on microbial community composition were similar in magnitude. In this Mediterranean ecosystem, plant control of microbial community composition was primarily due to effects on soil water content, whereas the changes in microbial community composition seasonally appeared to be due, in large part, to soil temperature. Available soil carbon was not a significant control on microbial community composition. Microbial community composition (PLFA) and 13C-PLFA ordination values were strongly related to intra-annual variability in soil enzyme activities and soil respiration, but microbial biomass was not. In this Mediterranean climate, soil microclimate appeared to be the master variable controlling microbial community composition and function. ?? 2006 Springer Science+Business Media, Inc.

Detecting insect pollinator declines on regional and global scales

USGS Publications Warehouse

Lubuhn, Gretchen; Droege, Sam; Connor, Edward F.; Gemmill-Herren, Barbara; Potts, Simon G.; Minckley, Robert L.; Griswold, Terry; Jean, Robert; Kula, Emanuel; Roubik, David W.; Cane, Jim; Wright, Karen W.; Frankie, Gordon; Parker, Frank

2013-01-01

Recently there has been considerable concern about declines in bee communities in agricultural and natural habitats. The value of pollination to agriculture, provided primarily by bees, is >$200 billion/year worldwide, and in natural ecosystems it is thought to be even greater. However, no monitoring program exists to accurately detect declines in abundance of insect pollinators; thus, it is difficult to quantify the status of bee communities or estimate the extent of declines. We used data from 11 multiyear studies of bee communities to devise a program to monitor pollinators at regional, national, or international scales. In these studies, 7 different methods for sampling bees were used and bees were sampled on 3 different continents. We estimated that a monitoring program with 200-250 sampling locations each sampled twice over 5 years would provide sufficient power to detect small (2-5%) annual declines in the number of species and in total abundance and would cost U.S.$2,000,000. To detect declines as small as 1% annually over the same period would require >300 sampling locations. Given the role of pollinators in food security and ecosystem function, we recommend establishment of integrated regional and international monitoring programs to detect changes in pollinator communities.

Using biodynamic models to reconcile differences between laboratory toxicity tests and field biomonitoring with aquatic insects

USGS Publications Warehouse

Buchwalter, D.B.; Cain, D.J.; Clements, W.H.; Luoma, S.N.

2007-01-01

Aquatic insects often dominate lotic ecosystems, yet these organisms are under-represented in trace metal toxicity databases. Furthermore, toxicity data for aquatic insects do not appear to reflect their actual sensitivities to metals in nature, because the concentrations required to elicit toxicity in the laboratory are considerably higher than those found to impact insect communities in the field. New approaches are therefore needed to better understand how and why insects are differentially susceptible to metal exposures. Biodynamic modeling is a powerful tool for understanding interspecific differences in trace metal bioaccumulation. Because bioaccumulation alone does not necessarily correlate with toxicity, we combined biokinetic parameters associated with dissolved cadmium exposures with studies of the subcellular compartmentalization of accumulated Cd. This combination of physiological traits allowed us to make predictions of susceptibility differences to dissolved Cd in three aquatic insect taxa: Ephemerella excrucians, Rhithrogena morrisoni, and Rhyacophila sp. We compared these predictions with long-term field monitoring data and toxicity tests with closely related taxa: Ephemerella infrequens, Rhithrogena hageni, and Rhyacophila brunea. Kinetic parameters allowed us to estimate steady-state concentrations, the time required to reach steady state, and the concentrations of Cd projected to be in potentially toxic compartments for different species. Species-specific physiological traits identified using biodynamic models provided a means for better understanding why toxicity assays with insects have failed to provide meaningful estimates for metal concentrations that would be expected to be protective in nature. ?? 2007 American Chemical Society.

[Comparison between transgenic insect-resistant cotton expressing Cry1Ac protein and its parental variety in rhizospheric fungal diversity].

PubMed

Pan, Jian-Gang; Jiao, Hai-Hua; Bai, Zhi-Hui; Qi, Hong-Yan; Ma, An-Zhou; Zhuang, Guo-qiang; Zhang, Hong-xun

2014-11-01

The dynamics of rhizospheric fungal diversity and biomass at different sampling stages associated with two transgenic insectresistant cottons expressing Cry1Ac protein and their control varieties were studied under greenhouse conditions, followed by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) and quantitative real-time polymerase chain reaction (Q-PCR), in order to evaluate the ecological security of planting transgenic cotton expressing Cry1Ac protein. The results indicated that the fungal superior bands in rhizosphere of transgenic Bt cotton were similar with that of control cotton at four sampling stages, the more obvious difference in the blurred bands among transgenic Bt cotton, JM20 and SHIYUAN321 was detected. The rhizospheric fungal biomass of transgenic Bt cotton SGK321 was significantly lower than that of its parental control cotton at seedling stage, while the slight decrease in fungal biomass of transgenic Bt cotton XP188 was detected at boll forming stage, the ill-defined decrease, even growing tendency in two transgenic Bt cottons was detected at other stages. However, the difference of rhizospheric fungal community compositions and biomass was not only existed between transgenic cotton and its control, but also between SHIYUAN321 and JM20, and the same phenomenon was also detected between transgenic Bt cotton SGK321 and XP188. Hence, Bt protein is not the only incentive resulting in the difference in fungal community composition and diversity, the decrease in biomass between transgenic cotton and untransgenic cotton, different cotton varieties has an effect on them.

The effect of remnant forest on insect successional response in tropical fire-impacted peatland: A bi-taxa comparison.

PubMed

Neoh, Kok-Boon; Bong, Lee-Jin; Muhammad, Ahmad; Itoh, Masayuki; Kozan, Osamu; Takematsu, Yoko; Yoshimura, Tsuyoshi

2017-01-01

Fire has become a common feature in tropical drained peatlands, and it may have detrimental impacts on the overall biodiversity of the forest ecosystem. We investigated the effect of fire on termite and ant assemblages and the importance of remnant forest in restoring species diversity in fire-impacted tropical peat swamp forests. The species loss of both termites and ants was as high as 50% in some fire-impacted peats compared to remnant forests, but in most cases the species richness for termites and ants was statistically equal along the land uses surveyed. However, a pronounced difference in functional group composition of termites was detected. In particular, sites close to remnant forests contained two additional termite feeding groups so that they shared a similar composition structure with remnant forests but were significantly different from sites distant from remnant forests. In general, ants were resilient to fire, and the similarity index showed a high degree of similarity among ant communities in all land uses surveyed. The Shannon diversity index for termites and ants decreased with increasing distance from the remnant forests and level of ecological degradation. Peat vegetation variables and ecological degradation were important in shaping termite and ant communities in the tropical peatlands, but their relative importance was not significant in fire-impacted peats regardless of distance from the remnant forests. This study highlights the importance of remnant forests as a biodiversity repository and natural buffer that can enhance species diversity and recolonization of forest-adapted species.

The effect of remnant forest on insect successional response in tropical fire-impacted peatland: A bi-taxa comparison

PubMed Central

Neoh, Kok-Boon; Bong, Lee-Jin; Muhammad, Ahmad; Itoh, Masayuki; Kozan, Osamu; Takematsu, Yoko; Yoshimura, Tsuyoshi

2017-01-01

Fire has become a common feature in tropical drained peatlands, and it may have detrimental impacts on the overall biodiversity of the forest ecosystem. We investigated the effect of fire on termite and ant assemblages and the importance of remnant forest in restoring species diversity in fire-impacted tropical peat swamp forests. The species loss of both termites and ants was as high as 50% in some fire-impacted peats compared to remnant forests, but in most cases the species richness for termites and ants was statistically equal along the land uses surveyed. However, a pronounced difference in functional group composition of termites was detected. In particular, sites close to remnant forests contained two additional termite feeding groups so that they shared a similar composition structure with remnant forests but were significantly different from sites distant from remnant forests. In general, ants were resilient to fire, and the similarity index showed a high degree of similarity among ant communities in all land uses surveyed. The Shannon diversity index for termites and ants decreased with increasing distance from the remnant forests and level of ecological degradation. Peat vegetation variables and ecological degradation were important in shaping termite and ant communities in the tropical peatlands, but their relative importance was not significant in fire-impacted peats regardless of distance from the remnant forests. This study highlights the importance of remnant forests as a biodiversity repository and natural buffer that can enhance species diversity and recolonization of forest-adapted species. PMID:28334021

Utilization of organic residues using heterotrophic microalgae and insects.

PubMed

Pleissner, Daniel; Rumpold, Birgit A

2018-02-01

Various organic residues occur globally in the form of straw, wood, green biomass, food waste, feces, manure etc. Other utilization strategies apart from anaerobic digestion, composting and incineration are needed to make use of the whole potential of organic residues as sources of various value added compounds. This review compares the cultivation of heterotrophic microalgae and insects using organic residues as nutrient sources and illuminates their potential with regard to biomass production, productivity and yield, and utilization strategies of produced biomasses. Furthermore, cultivation processes as well as advantages and disadvantages of utilization processes are identified and discussed. It was shown that both heterotrophic algae and insects are able to reduce a sufficient amount of organic residues by converting it into biomass. The biomass composition of both organisms is similar which allows similar utilization strategies in food and feed, chemicals and materials productions. Even though insect is the more complex organism, biomass production can be carried out using simple equipment without sterilization and hydrolysis of organic residues. Contrarily, heterotrophic microalgae require a pretreatment of organic residues in form of sterilization and in most cases hydrolysis. Interestingly, the volumetric productivity of insect biomass exceeds the productivity of algal biomass. Despite legal restrictions, it is expected that microalgae and insects will find application as alternative food and feed sources in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial Structure of the Mormon Cricket Gut Microbiome and its Predicted Contribution to Nutrition and Immune Function

PubMed Central

Smith, Chad C.; Srygley, Robert B.; Healy, Frank; Swaminath, Karthikeyan; Mueller, Ulrich G.

2017-01-01

The gut microbiome of insects plays an important role in their ecology and evolution, participating in nutrient acquisition, immunity, and behavior. Microbial community structure within the gut is heavily influenced by differences among gut regions in morphology and physiology, which determine the niches available for microbes to colonize. We present a high-resolution analysis of the structure of the gut microbiome in the Mormon cricket Anabrus simplex, an insect known for its periodic outbreaks in the western United States and nutrition-dependent mating system. The Mormon cricket microbiome was dominated by 11 taxa from the Lactobacillaceae, Enterobacteriaceae, and Streptococcaceae. While most of these were represented in all gut regions, there were marked differences in their relative abundance, with lactic-acid bacteria (Lactobacillaceae) more common in the foregut and midgut and enteric (Enterobacteriaceae) bacteria more common in the hindgut. Differences in community structure were driven by variation in the relative prevalence of three groups: a Lactobacillus in the foregut, Pediococcus lactic-acid bacteria in the midgut, and Pantoea agglomerans, an enteric bacterium, in the hindgut. These taxa have been shown to have beneficial effects on their hosts in insects and other animals by improving nutrition, increasing resistance to pathogens, and modulating social behavior. Using PICRUSt to predict gene content from our 16S rRNA sequences, we found enzymes that participate in carbohydrate metabolism and pathogen defense in other orthopterans. These were predominately represented in the hindgut and midgut, the most important sites for nutrition and pathogen defense. Phylogenetic analysis of 16S rRNA sequences from cultured isolates indicated low levels of divergence from sequences derived from plants and other insects, suggesting that these bacteria are likely to be exchanged between Mormon crickets and the environment. Our study shows strong spatial variation in microbiome community structure, which influences predicted gene content and thus the potential of the microbiome to influence host function. PMID:28553263

Do Native Insects and Associated Fungi Limit Non-Native Woodwasp, Sirex noctilio, Survival in a Newly Invaded Environment?

PubMed Central

Haavik, Laurel J.; Dodds, Kevin J.; Allison, Jeremy D.

2015-01-01

Sirex noctilio F. (Hymenoptera: Siricidae) is an introduced pest of pines (Pinus spp.) in several countries in the Southern Hemisphere. Although S. noctilio is established in North America (first discovered in 2004), it has not been a destructive pest there so far, where forest communities more closely resemble those in its native Eurasian range—where it is not a pest. To investigate the influence of the existing community of associated insects (competitors + natural enemies) and fungi (vectored by insects) on S. noctilio survival in North America, we examined stage-specific mortality factors and their relative importance, generating life tables drawn from experimentally-manipulated and natural cohorts of Sirex spp. (mostly S. noctilio, but some native S. nigricornis F.). For both natural and experimentally-manipulated cohorts, factors which acted during the earliest Sirex life stages, most likely tree resistance and/or competition among fungal associates, were paramount in dictating woodwasp survival. Experimentally-manipulated life tables revealed that protection from the community of associates resulted in a significantly, and substantially larger (>15x) S. noctilio F1 generation than exposure to it. Seventy percent of generation mortality in the exposed cohort was due to tree resistance or unknown causes early in larval development, which could have included competition among other bark- or wood-inhabiting insects and/or their fungal associates. Only 46% of generation mortality in the protected cohort was due to tree resistance and/or unknown causes. Parasitoids, particularly endoparasitoids (Ibalia spp.), showed limited ability to control S. noctilio, and reduced the experimentally-established cohort by only 11%, and natural cohorts an average of 3.4%. The relative importance of tree resistance vs. competition with bark- and wood-borers in reducing S. noctilio survival remains unclear. Tree resistance and/or competition likely contribute more than natural enemies in maintaining the S. noctilio population in North America below damaging levels. PMID:26447845

Long-term priority effects among insects and fungi colonizing decaying wood.

PubMed

Weslien, Jan; Djupström, Line B; Schroeder, Martin; Widenfalk, Olof

2011-11-01

1. Priority effects have been hypothesized to have long-lasting impact on community structure in natural ecosystems. Long-term studies of priority effects in natural ecosystems are however sparse, especially in terrestrial ecosystems. 2. Wood decay is a slow process involving a high diversity of insect and fungus species. Species interactions that drive change in communities of insects and fungi during wood decay are poorly understood because of a lack of sufficient long-term studies. 3. In this paper, we followed the colonization and succession of wood-living insects and fungi on cut trees during 15 years, from tree death and onwards, in a boreal forest landscape. We test the long-term priority effects hypothesis that the identity and abundance of species that colonize first affect the colonization success of later-arriving species. We also hypothesize that species interact in both facilitative and inhibitory ways, which ultimately affect habitat quality for a red-listed late-succession beetle species. 4. Possible causal associations between species were explored by path analysis. The results indicate that one bark beetle species, Hylurgops palliatus, and one wood-borer species, Monochamus sutor, which colonized the wood during the first year after cutting, influenced the occurrence of a rare, wood-living beetle, Peltis grossa, that started to emerge from the stumps about 10 years later. The positive effects of Hylurgops palliatus and negative effects of M. sutor were largely mediated through the wood-decaying fungus species Fomitopsis pinicola. 5. The study shows that variable priority effects may have long-lasting impact on community assembly in decaying wood. The study also exemplifies new possibilities for managing populations of threatened species by exploring links between early, well-understood species guilds and late, more poorly understood species guilds. © 2011 The Authors. Journal of Animal Ecology © 2011 British Ecological Society.

Host and Symbiont Jointly Control Gut Microbiota during Complete Metamorphosis

PubMed Central

Johnston, Paul R.; Rolff, Jens

2015-01-01

Holometabolous insects undergo a radical anatomical re-organisation during metamorphosis. This poses a developmental challenge: the host must replace the larval gut but at the same time retain symbiotic gut microbes and avoid infection by opportunistic pathogens. By manipulating host immunity and bacterial competitive ability, we study how the host Galleria mellonella and the symbiotic bacterium Enterococcus mundtii interact to manage the composition of the microbiota during metamorphosis. Disenabling one or both symbiotic partners alters the composition of the gut microbiota, which incurs fitness costs: adult hosts with a gut microbiota dominated by pathogens such as Serratia and Staphylococcus die early. Our results reveal an interaction that guarantees the safe passage of the symbiont through metamorphosis and benefits the resulting adult host. Host-symbiont “conspiracies” as described here are almost certainly widespread in holometobolous insects including many disease vectors. PMID:26544881

The Gut Microbiome of the Vector Lutzomyia longipalpis Is Essential for Survival of Leishmania infantum.

PubMed

Kelly, Patrick H; Bahr, Sarah M; Serafim, Tiago D; Ajami, Nadim J; Petrosino, Joseph F; Meneses, Claudio; Kirby, John R; Valenzuela, Jesus G; Kamhawi, Shaden; Wilson, Mary E

2017-01-17

The vector-borne disease leishmaniasis, caused by Leishmania species protozoa, is transmitted to humans by phlebotomine sand flies. Development of Leishmania to infective metacyclic promastigotes in the insect gut, a process termed metacyclogenesis, is an essential prerequisite for transmission. Based on the hypothesis that vector gut microbiota influence the development of virulent parasites, we sequenced midgut microbiomes in the sand fly Lutzomyia longipalpis with or without Leishmania infantum infection. Sucrose-fed sand flies contained a highly diverse, stable midgut microbiome. Blood feeding caused a decrease in microbial richness that eventually recovered. However, bacterial richness progressively decreased in L. infantum-infected sand flies. Acetobacteraceae spp. became dominant and numbers of Pseudomonadaceae spp. diminished coordinately as the parasite underwent metacyclogenesis and parasite numbers increased. Importantly, antibiotic-mediated perturbation of the midgut microbiome rendered sand flies unable to support parasite growth and metacyclogenesis. Together, these data suggest that the sand fly midgut microbiome is a critical factor for Leishmania growth and differentiation to its infective state prior to disease transmission. Leishmania infantum, a parasitic protozoan causing fatal visceral leishmaniasis, is transmitted to humans through the bite of the sand fly Lutzomyia longipalpis Development of the parasite to its virulent metacyclic state occurs in the sand fly gut. In this study, the microbiota within the Lu. longipalpis midgut was delineated by 16S ribosomal DNA (rDNA) sequencing, revealing a highly diverse community composition that lost diversity as parasites developed to their metacyclic state and increased in abundance in infected flies. Perturbing sand fly gut microbiota with an antibiotic cocktail, which alone had no effect on either the parasite or the fly, arrested both the development of virulent parasites and parasite expansion. These findings indicate the importance of bacterial commensals within the insect vector for the development of virulent pathogens, and raise the possibility that impairing the microbial composition within the vector might represent a novel approach to control of vector-borne diseases. Copyright © 2017 Kelly et al.

The Comet assay in insects--Status, prospects and benefits for science.

PubMed

Augustyniak, Maria; Gladysz, Marcin; Dziewięcka, Marta

2016-01-01

The Comet assay has been recently adapted to investigate DNA damage in insects. The first reports of its use in Drosophila melanogaster appeared in 2002. Since then, the interest in the application of the Comet assay to studies of insects has been rapidly increasing. Many authors see substantial potential in the use of the Comet assay in D. melanogaster for medical toxicology studies. This application could allow the testing of drugs and result in an understanding of the mechanisms of action of toxins, which could significantly influence the limited research that has been performed on vertebrates. The possible perspectives and benefits for science are considered in this review. In the last decade, the use of the Comet assay has been described in insects other than D. melanogaster. Specifically, methods to prepare a cell suspension from insect tissues, which is a difficult task, were analyzed and compared in detail. Furthermore, attention was paid to any differences and modifications in the research protocols, such as the buffer composition and electrophoresis conditions. Various scientific fields in addition to toxicological and ecotoxicological research were considered. We expect the Comet assay to be used in environmental risk assessments and to improve our understanding of many important phenomena of insect life, such as metamorphosis, molting, diapause and quiescence. The use of this method to study species that are of key importance to humans, such as pests and beneficial insects, appears to be highly probable and very promising. The use of the Comet assay for DNA stability testing in insects will most likely rapidly increase in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

Codon bias and gene ontology in holometabolous and hemimetabolous insects.

PubMed

Carlini, David B; Makowski, Matthew

2015-12-01

The relationship between preferred codon use (PCU), developmental mode, and gene ontology (GO) was investigated in a sample of nine insect species with sequenced genomes. These species were selected to represent two distinct modes of insect development, holometabolism and hemimetabolism, with an aim toward determining whether the differences in developmental timing concomitant with developmental mode would be mirrored by differences in PCU in their developmental genes. We hypothesized that the developmental genes of holometabolous insects should be under greater selective pressure for efficient translation, manifest as increased PCU, than those of hemimetabolous insects because holometabolism requires abundant protein expression over shorter time intervals than hemimetabolism, where proteins are required more uniformly in time. Preferred codon sets were defined for each species, from which the frequency of PCU for each gene was obtained. Although there were substantial differences in the genomic base composition of holometabolous and hemimetabolous insects, both groups exhibited a general preference for GC-ending codons, with the former group having higher PCU averaged across all genes. For each species, the biological process GO term for each gene was assigned that of its Drosophila homolog(s), and PCU was calculated for each GO term category. The top two GO term categories for PCU enrichment in the holometabolous insects were anatomical structure development and cell differentiation. The increased PCU in the developmental genes of holometabolous insects may reflect a general strategy to maximize the protein production of genes expressed in bursts over short time periods, e.g., heat shock proteins. J. Exp. Zool. (Mol. Dev. Evol.) 324B: 686-698, 2015. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

[Effects of grazing on the composition of soil animals and their decomposition function to Stipa grandis litter in Inner Mongolia typical steppe, China.

PubMed

Yang, Zhi Min; Hasitamier; Liu, Xin Min

2016-09-01

Grazing has been considered to be an important factor determining the composition of soil animals and decomposition of leaf litter in grassland ecosystem. Sampling plots were selected in ungrazed grassland, grazed grassland and sandy land. Litter bags were used to compare the changes of physicochemical properties of Stipa grandis litter and the composition of soil fauna in the process of the litter decomposition in Baiyinxile, Inner Mongolia, since 2010 to 2012. A total number of 67056 soil animals were captured, belonging to five phyla and eight classes, including 23 families of mites and 19 families of insects. After 780 days' decomposition, the loss of the organic matter of S. grandis litter was from 92.5% to 40.0% in the ungrazed grassland, and to 41.3% in the grazed grassland, with no significant difference observed. However, there was a significant difference (P<0.05) between the ratio of litter residues of the ungrazed grassland (50.0%) and that of the grazed grassland (23.0%). The abundance of soil animals in the residual litters was significantly decreased in the grazed grassland compared to the ungrazed grassland. When the litter was moved into the sandy land, the decomposition rate of organic matter in the residual litter was not significant changed but the ratio of litter residue declined significantly, and the composition of mite community in the resi-dual litter changed significantly. Our results illustrated that grazing activity could affect the composition and abundance of soil fauna in temperate grassland, but slightly influenced the decomposition of organic matter. Therefore, soil animals had relatively weak direct effects on the decomposition of litter in this semi-arid region.

The Gut Commensal Microbiome of Drosophila melanogaster Is Modified by the Endosymbiont Wolbachia

PubMed Central

Fast, Eva M.; Guo, Rong; Vaisman, Natalie; Ortiz, Luis; Bybee, Joanna; Slatko, Barton E.

2017-01-01

ABSTRACT Endosymbiotic Wolbachia bacteria and the gut microbiome have independently been shown to affect several aspects of insect biology, including reproduction, development, life span, stem cell activity, and resistance to human pathogens, in insect vectors. This work shows that Wolbachia bacteria, which reside mainly in the fly germline, affect the microbial species present in the fly gut in a lab-reared strain. Drosophila melanogaster hosts two main genera of commensal bacteria—Acetobacter and Lactobacillus. Wolbachia-infected flies have significantly reduced titers of Acetobacter. Sampling of the microbiome of axenic flies fed with equal proportions of both bacteria shows that the presence of Wolbachia bacteria is a significant determinant of the composition of the microbiome throughout fly development. However, this effect is host genotype dependent. To investigate the mechanism of microbiome modulation, the effect of Wolbachia bacteria on Imd and reactive oxygen species pathways, the main regulators of immune response in the fly gut, was measured. The presence of Wolbachia bacteria does not induce significant changes in the expression of the genes for the effector molecules in either pathway. Furthermore, microbiome modulation is not due to direct interaction between Wolbachia bacteria and gut microbes. Confocal analysis shows that Wolbachia bacteria are absent from the gut lumen. These results indicate that the mechanistic basis of the modulation of composition of the microbiome by Wolbachia bacteria is more complex than a direct bacterial interaction or the effect of Wolbachia bacteria on fly immunity. The findings reported here highlight the importance of considering the composition of the gut microbiome and host genetic background during Wolbachia-induced phenotypic studies and when formulating microbe-based disease vector control strategies. IMPORTANCE Wolbachia bacteria are intracellular bacteria present in the microbiome of a large fraction of insects and parasitic nematodes. They can block mosquitos’ ability to transmit several infectious disease-causing pathogens, including Zika, dengue, chikungunya, and West Nile viruses and malaria parasites. Certain extracellular bacteria present in the gut lumen of these insects can also block pathogen transmission. However, our understanding of interactions between Wolbachia and gut bacteria and how they influence each other is limited. Here we show that the presence of Wolbachia strain wMel changes the composition of gut commensal bacteria in the fruit fly. Our findings implicate interactions between bacterial species as a key factor in determining the overall composition of the microbiome and thus reveal new paradigms to consider in the development of disease control strategies. PMID:28932814

The Gut Commensal Microbiome of Drosophila melanogaster Is Modified by the Endosymbiont Wolbachia.

PubMed

Simhadri, Rama K; Fast, Eva M; Guo, Rong; Schultz, Michaela J; Vaisman, Natalie; Ortiz, Luis; Bybee, Joanna; Slatko, Barton E; Frydman, Horacio M

2017-01-01

Endosymbiotic Wolbachia bacteria and the gut microbiome have independently been shown to affect several aspects of insect biology, including reproduction, development, life span, stem cell activity, and resistance to human pathogens, in insect vectors. This work shows that Wolbachia bacteria, which reside mainly in the fly germline, affect the microbial species present in the fly gut in a lab-reared strain. Drosophila melanogaster hosts two main genera of commensal bacteria- Acetobacter and Lactobacillus . Wolbachia -infected flies have significantly reduced titers of Acetobacter . Sampling of the microbiome of axenic flies fed with equal proportions of both bacteria shows that the presence of Wolbachia bacteria is a significant determinant of the composition of the microbiome throughout fly development. However, this effect is host genotype dependent. To investigate the mechanism of microbiome modulation, the effect of Wolbachia bacteria on Imd and reactive oxygen species pathways, the main regulators of immune response in the fly gut, was measured. The presence of Wolbachia bacteria does not induce significant changes in the expression of the genes for the effector molecules in either pathway. Furthermore, microbiome modulation is not due to direct interaction between Wolbachia bacteria and gut microbes. Confocal analysis shows that Wolbachia bacteria are absent from the gut lumen. These results indicate that the mechanistic basis of the modulation of composition of the microbiome by Wolbachia bacteria is more complex than a direct bacterial interaction or the effect of Wolbachia bacteria on fly immunity. The findings reported here highlight the importance of considering the composition of the gut microbiome and host genetic background during Wolbachia -induced phenotypic studies and when formulating microbe-based disease vector control strategies. IMPORTANCE Wolbachia bacteria are intracellular bacteria present in the microbiome of a large fraction of insects and parasitic nematodes. They can block mosquitos' ability to transmit several infectious disease-causing pathogens, including Zika, dengue, chikungunya, and West Nile viruses and malaria parasites. Certain extracellular bacteria present in the gut lumen of these insects can also block pathogen transmission. However, our understanding of interactions between Wolbachia and gut bacteria and how they influence each other is limited. Here we show that the presence of Wolbachia strain w Mel changes the composition of gut commensal bacteria in the fruit fly. Our findings implicate interactions between bacterial species as a key factor in determining the overall composition of the microbiome and thus reveal new paradigms to consider in the development of disease control strategies.

A Physiological and Behavioral Mechanism for Leaf Herbivore-Induced Systemic Root Resistance1[OPEN

PubMed Central

Erb, Matthias; Robert, Christelle A.M.; Marti, Guillaume; Lu, Jing; Doyen, Gwladys R.; Villard, Neil; Barrière, Yves; Wolfender, Jean-Luc; Turlings, Ted C.J.

2015-01-01

Indirect plant-mediated interactions between herbivores are important drivers of community composition in terrestrial ecosystems. Among the most striking examples are the strong indirect interactions between spatially separated leaf- and root-feeding insects sharing a host plant. Although leaf feeders generally reduce the performance of root herbivores, little is known about the underlying systemic changes in root physiology and the associated behavioral responses of the root feeders. We investigated the consequences of maize (Zea mays) leaf infestation by Spodoptera littoralis caterpillars for the root-feeding larvae of the beetle Diabrotica virgifera virgifera, a major pest of maize. D. virgifera strongly avoided leaf-infested plants by recognizing systemic changes in soluble root components. The avoidance response occurred within 12 h and was induced by real and mimicked herbivory, but not wounding alone. Roots of leaf-infested plants showed altered patterns in soluble free and soluble conjugated phenolic acids. Biochemical inhibition and genetic manipulation of phenolic acid biosynthesis led to a complete disappearance of the avoidance response of D. virgifera. Furthermore, bioactivity-guided fractionation revealed a direct link between the avoidance response of D. virgifera and changes in soluble conjugated phenolic acids in the roots of leaf-attacked plants. Our study provides a physiological mechanism for a behavioral pattern that explains the negative effect of leaf attack on a root-feeding insect. Furthermore, it opens up the possibility to control D. virgifera in the field by genetically mimicking leaf herbivore-induced changes in root phenylpropanoid patterns. PMID:26430225

What mediates tree mortality during drought in the southern Sierra Nevada?

USGS Publications Warehouse

Paz-Kagan, Tarin; Brodrick, Philip; Vaughn, Nicholas R.; Das, Adrian J.; Stephenson, Nathan L.; Nydick, Koren R.; Asner, Gregory P.

2017-01-01

Severe drought has the potential to cause selective mortality within a forest, thereby inducing shifts in forest species composition. The southern Sierra Nevada foothills and mountains of California have experienced extensive forest dieback due to drought stress and insect outbreak. We used high-fidelity imaging spectroscopy (HiFIS) and light detection and ranging (LiDAR) from the Carnegie Airborne Observatory (CAO) to estimate the effect of forest dieback on species composition in response to drought stress in Sequoia National Park. Our aims were: (1) to quantify site-specific conditions that mediate tree mortality along an elevation gradient in the southern Sierra Nevada Mountains; (2) to assess where mortality events have a greater probability of occurring; and (3) to estimate which tree species have a greater likelihood of mortality along the elevation gradient. A series of statistical models were generated to classify species composition and identify tree mortality, and the influences of different environmental factors were spatially quantified and analyzed to assess where mortality events have a greater likelihood of occurring. A higher probability of mortality was observed in the lower portion of the elevation gradient, on southwest and west-facing slopes, in areas with shallow soils, on shallower slopes, and at greater distances from water. All of these factors are related to site water balance throughout the landscape. Our results also suggest that mortality is species-specific along the elevation gradient, mainly affecting Pinus ponderosa and Pinus lambertiana at lower elevations. Selective mortality within the forest may drive long-term shifts in community composition along the elevation gradient.

What mediates tree mortality during drought in the southern Sierra Nevada?

PubMed

Paz-Kagan, Tarin; Brodrick, Philip G; Vaughn, Nicholas R; Das, Adrian J; Stephenson, Nathan L; Nydick, Koren R; Asner, Gregory P

2017-12-01

Severe drought has the potential to cause selective mortality within a forest, thereby inducing shifts in forest species composition. The southern Sierra Nevada foothills and mountains of California have experienced extensive forest dieback due to drought stress and insect outbreak. We used high-fidelity imaging spectroscopy (HiFIS) and light detection and ranging (LiDAR) from the Carnegie Airborne Observatory (CAO) to estimate the effect of forest dieback on species composition in response to drought stress in Sequoia National Park. Our aims were (1) to quantify site-specific conditions that mediate tree mortality along an elevation gradient in the southern Sierra Nevada Mountains, (2) to assess where mortality events have a greater probability of occurring, and (3) to estimate which tree species have a greater likelihood of mortality along the elevation gradient. A series of statistical models were generated to classify species composition and identify tree mortality, and the influences of different environmental factors were spatially quantified and analyzed to assess where mortality events have a greater likelihood of occurring. A higher probability of mortality was observed in the lower portion of the elevation gradient, on southwest- and west-facing slopes, in areas with shallow soils, on shallower slopes, and at greater distances from water. All of these factors are related to site water balance throughout the landscape. Our results also suggest that mortality is species-specific along the elevation gradient, mainly affecting Pinus ponderosa and Pinus lambertiana at lower elevations. Selective mortality within the forest may drive long-term shifts in community composition along the elevation gradient. © 2017 by the Ecological Society of America.

Functional invertebrate prey groups reflect dietary responses to phenology and farming activity and pest control services in three sympatric species of aerially foraging insectivorous birds.

PubMed

Orłowski, Grzegorz; Karg, Jerzy; Karg, Grzegorz

2014-01-01

Farming activity severely impacts the invertebrate food resources of farmland birds, with direct mortality to populations of above-ground arthropods thorough mechanical damage during crop harvests. In this study we assessed the effects of phenological periods, including the timing of harvest, on the composition and biomass of prey consumed by three species of aerial insectivorous birds. Common Swifts Apus apus, Barn Swallows Hirundo rustica and House Martins Delichon urbica breed sympatrically and most of their diet is obtained from agricultural sources of invertebrate prey, especially from oil-seed rape crops. We categorized invertebrate prey into six functional groups, including oil-seed rape pests; pests of other arable crops; other crop-provisioned taxa; coprophilous taxa; and taxa living in non-crop and mixed crop/non-crop habitats. Seasonality impacted functional groups differently, but the general direction of change (increase/decrease) of all groups was consistent as indexed by prey composition of the three aerial insectivores studied here. After the oil-seed rape crop harvest (mid July), all three species exhibited a dietary shift from oil-seed rape insect pests to other aerial invertebrate prey groups. However, Common Switfts also consumed a relative large quantity of oil-seed rape insect pests in the late summer (August), suggesting that they could reduce pest insect emigration beyond the host plant/crop. Since these aerially foraging insectivorous birds operate in specific conditions and feed on specific pest resources unavailable to foliage/ground foraging avian predators, our results suggest that in some crops like oil-seed rape cultivations, the potential integration of the insectivory of aerial foraging birds into pest management schemes might provide economic benefits. We advise further research into the origin of airborne insects and the role of aerial insectivores as agents of the biological control of crop insect pests, especially the determination of depredation rates and the cascading effects of insectivory on crop damage and yield.

Helicoverpa zea (Lepidoptera: Noctuidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) Responses to Sorghum bicolor (Poales: Poaceae) Tissues From Lowered Lignin Lines.

PubMed

Dowd, Patrick F; Sattler, Scott E

2015-01-01

The presence of lignin within biomass impedes the production of liquid fuels. Plants with altered lignin content and composition are more amenable to lignocellulosic conversion to ethanol and other biofuels but may be more susceptible to insect damage where lignin is an important resistance factor. However, reduced lignin lines of switchgrasses still retained insect resistance in prior studies. Therefore, we hypothesized that sorghum lines with lowered lignin content will also retain insect resistance. Sorghum excised leaves and stalk pith Sorghum bicolor (L.) Moench (Poales: Poaceae) from near isogenic brown midrib (bmr) 6 and 12 mutants lines, which have lowered lignin content and increased lignocellulosic ethanol conversion efficiency, were examined for insect resistance relative to wild-type (normal BTx623). Greenhouse and growth chamber grown plant tissues were fed to first-instar larvae of corn earworms, Helicoverpa zea (Boddie) and fall armyworms Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), two sorghum major pests. Younger bmr leaves had significantly greater feeding damage in some assays than wild-type leaves, but older bmr6 leaves generally had significantly less damage than wild-type leaves. Caterpillars feeding on the bmr6 leaves often weighed significantly less than those feeding on wild-type leaves, especially in the S. frugiperda assays. Larvae fed the pith from bmr stalks had significantly higher mortality compared with those larvae fed on wild-type pith, which suggested that bmr pith was more toxic. Thus, reducing lignin content or changing subunit composition of bioenergy grasses does not necessarily increase their susceptibility to insects and may result in increased resistance, which would contribute to sustainable production. Published by Oxford University Press on behalf of the Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

Language of plants: Where is the word?

PubMed

Šimpraga, Maja; Takabayashi, Junji; Holopainen, Jarmo K

2016-04-01

Plants emit biogenic volatile organic compounds (BVOCs) causing transcriptomic, metabolomic and behavioral responses in receiver organisms. Volatiles involved in such responses are often called "plant language". Arthropods having sensitive chemoreceptors can recognize language released by plants. Insect herbivores, pollinators and natural enemies respond to composition of volatiles from plants with specialized receptors responding to different types of compounds. In contrast, the mechanism of how plants "hear" volatiles has remained obscured. In a plant-plant communication, several individually emitted compounds are known to prime defense response in receiver plants with a specific manner according to the chemical structure of each volatile compound. Further, composition and ratio of volatile compounds in the plant-released plume is important in plant-insect and plant-plant interactions mediated by plant volatiles. Studies on volatile-mediated plant-plant signaling indicate that the signaling distances are rather short, usually not longer than one meter. Volatile communication from plants to insects such as pollinators could be across distances of hundreds of meters. As many of the herbivore induced VOCs have rather short atmospheric life times, we suggest that in long-distant communications with plant volatiles, reaction products in the original emitted compounds may have additional information value of the distance to emission source together with the original plant-emitted compounds. © 2015 Institute of Botany, Chinese Academy of Sciences.

Omega-3 long-chain polyunsaturated fatty acids support aerial insectivore performance more than food quantity.

PubMed

Twining, Cornelia W; Brenna, J Thomas; Lawrence, Peter; Shipley, J Ryan; Tollefson, Troy N; Winkler, David W

2016-09-27

Once-abundant aerial insectivores, such as the Tree Swallow (Tachycineta bicolor), have declined steadily in the past several decades, making it imperative to understand all aspects of their ecology. Aerial insectivores forage on a mixture of aquatic and terrestrial insects that differ in fatty acid composition, specifically long-chain omega-3 polyunsaturated fatty acid (LCPUFA) content. Aquatic insects contain high levels of both LCPUFA and their precursor omega-3 PUFA, alpha-linolenic acid (ALA), whereas terrestrial insects contain much lower levels of both. We manipulated both the quantity and quality of food for Tree Swallow chicks in a full factorial design. Diets were either high-LCPUFA or low in LCPUFA but high in ALA, allowing us to separate the effects of direct LCPUFA in diet from the ability of Tree Swallows to convert their precursor, ALA, into LCPUFA. We found that fatty acid composition was more important for Tree Swallow chick performance than food quantity. On high-LCPUFA diets, chicks grew faster, were in better condition, and had greater immunocompetence and lower basal metabolic rates compared with chicks on both low LCPUFA diets. Increasing the quantity of high-LCPUFA diets resulted in improvements to all metrics of performance while increasing the quantity of low-LCPUFA diets only resulted in greater immunocompetence and lower metabolic rates. Chicks preferentially retained LCPUFA in brain and muscle when both food quantity and LCPUFA were limited. Our work suggests that fatty acid composition is an important dimension of aerial insectivore nutritional ecology and reinforces the importance of high-quality aquatic habitat for these declining birds.

Genotyping of Trypanosoma cruzi in a hyper-endemic area of Colombia reveals an overlap among domestic and sylvatic cycles of Chagas disease

PubMed Central

2014-01-01

Background Chagas disease is a neglected illness caused by the Trypanosoma cruzi parasite, which widely affects American communities. This study attempted to identify T. cruzi genotypes circulating in four indigenous communities of the Sierra Nevada of Santa Marta, Colombia, to investigate parasite transmission dynamics in these communities. In addition, some epidemiological variables to determine the risk factors for infection with this parasite, such as the prevalence of T. cruzi infection, the triatomine species, and the domestic and sylvatic mammals that act as vectors and reservoirs of the parasite in the domestic, peridomestic and sylvatic cycles, were examined. Methods We developed a prospective study to identify the main risk factors associated with T. cruzi infection in the region. The T. cruzi prevalence was determined by ELISA, IFA and PCR. Triatomines species and both domestic and sylvatic mammals from all communities were captured and sampled. To analyze parasite transmission dynamics in these four communities, eight DNA parasite probes were generated from insect and reservoir samples, and a DNA blot analysis were carried out. Results Serological studies revealed 37% prevalence in the four communities, and Kasakumake was the most endemic region, containing approximately 70% seropositives. Moreover, the molecular diagnosis showed a high correlation between the serological data and the T. cruzi circulating in the patients’ blood. A total of 464 triatomine insects were collected in domestic, peridomestic and sylvatic environments, and these insects belonged to five different species; Rhodnius prolixus and Triatoma dimidiata were the two more important species transmitting the parasite. After studying the eco-epidemiological factors in these four communities, the most important risk factors for infection with the parasite were determined. These risk factors are a high infection rate of people and domestic animals, the construction materials of the houses, the presence of infected triatomines inside the human dwellings, the proximity between houses and a sylvatic environment with several triatomine species and wild animals. Finally, the molecular characterization of T. cruzi showed the presence of three haplotypes and complex T. cruzi mixed infections in all reservoirs. Conclusions Active transmission of T. cruzi is present in four indigenous communities of the Sierra Nevada de Santa Marta with overlap between the domestic and the sylvatic transmission cycles of Chagas disease. PMID:24656115

Anti-mosquito plants as an alternative or incremental method for malaria vector control among rural communities of Bagamoyo District, Tanzania.

PubMed

Innocent, Ester; Hassanali, Ahmed; Kisinza, William Nw; Mutalemwa, Prince Pp; Magesa, Stephen; Kayombo, Edmund

2014-07-11

Plants represent one of the most accessible resources available for mosquito control by communities in Tanzania. However, no documented statistics exist for their contribution in the management of mosquitoes and other insects except through verbal and some publications. This study aimed at assessing communities' knowledge, attitudes and practices of using plants as an alternative method for mosquito control among selected communities in a malaria-prone area in Tanzania. Questionnaires were administered to 202 respondents from four villages of Bagamoyo District, Pwani Region, in Tanzania followed by participatory rural appraisal with village health workers. Secondary data collection for plants mentioned by the communities was undertaken using different search engines such as googlescholar, PubMED and NAPRALERT. Results showed about 40.3% of respondents used plants to manage insects, including mosquitoes. A broad profile of plants are used, including "mwarobaini" (Azadirachta indica) (22.5%), "mtopetope" (Annona spp) (20.8%), "mchungwa/mlimau" (Citrus spp) (8.3%), "mvumbashi/uvumbati" (Ocimum spp) (7.4%), "mkorosho" (Anacadium occidentale) (7.1%), "mwembe" (5.4%) (Mangifera indica), "mpera" (4.1%) (Psidium spp) and "maganda ya nazi" (4.1%) (Cocos nucifera). Majority of respondents collected these plants from the wild (54.2%), farms (28.9%) and/or home gardens (6%). The roles played by these plants in fighting mosquitoes is reflected by the majority that deploy them with or without bed-nets (p > 0.55) or insecticidal sprays (p >0.22). Most respondents were aware that mosquitoes transmit malaria (90.6%) while few respondents associated elephantiasis/hydrocele (46.5%) and yellow fever (24.3%) with mosquitoes. Most of the ethnobotanical uses mentioned by the communities were consistent with scientific information gathered from the literature, except for Psidium guajava, which is reported for the first time in insect control. This survey has indicated some knowledge gap among community members in managing mosquito vectors using plant. The communities need a basic health education and sensitization for effective exploitation of this valuable tool for reducing mosquitoes and associated disease burdens. On the other hand, the government of Tanzania should strengthen advocacy of botanical pesticides development, registration and regulation for public health benefits because they are source of pest control tools people rely on them.

Aboveground and belowground arthropods experience different relative influences of stochastic versus deterministic community assembly processes following disturbance

PubMed Central

Martinez, Alexander S.; Faist, Akasha M.

2016-01-01

Background Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces. Methods Using a disturbance gradient along a 5-year chronosequence of insect-induced tree mortality in a subalpine forest of the southern Rocky Mountains, Colorado, USA, we examined changes in community structure and relative influences of deterministic and stochastic processes in the assembly of aboveground (surface and litter-active species) and belowground (species active in organic and mineral soil layers) arthropod communities. Arthropods were sampled for all years of the chronosequence via pitfall traps (aboveground community) and modified Winkler funnels (belowground community) and sorted to morphospecies. Community structure of both communities were assessed via comparisons of morphospecies abundance, diversity, and composition. Assembly processes were inferred from a mixture of linear models and matrix correlations testing for community associations with environmental properties, and from null-deviation models comparing observed vs. expected levels of species turnover (Beta diversity) among samples. Results Tree mortality altered community structure in both aboveground and belowground arthropod communities, but null models suggested that aboveground communities experienced greater relative influences of deterministic processes, while the relative influence of stochastic processes increased for belowground communities. Additionally, Mantel tests and linear regression models revealed significant associations between the aboveground arthropod communities and vegetation and soil properties, but no significant association among belowground arthropod communities and environmental factors. Discussion Our results suggest context-dependent influences of stochastic and deterministic community assembly processes across different fractions of a spatially co-occurring ground-dwelling arthropod community following disturbance. This variation in assembly may be linked to contrasting ecological strategies and dispersal rates within above- and below-ground communities. Our findings add to a growing body of evidence indicating concurrent influences of stochastic and deterministic processes in community assembly, and highlight the need to consider potential variation across different fractions of biotic communities when testing community ecology theory and considering conservation strategies. PMID:27761333

Species richness in natural and disturbed habitats: Asteraceae and Flower-head insects (Tephritidae: Diptera).

PubMed

Diniz, Soraia; Prado, Paulo I; Lewinsohn, Thomas M

2010-01-01

Anthropogenic changes in the landscape result in an environmental mosaic with serious consequences for biodiversity. The aim of the present study was to assess the effects of the anthropogenic changes on Asteraceae richness and abundance, and to evaluate the consequences for the richness of Tephritidae assemblages in five sampling sites, with three sampled habitats in each: cerrado (Brazilian savanna), eucalyptus stands and pasture. Sampling was carried out in 15 random transects (cerrados and one pasture) and in 30 transects (eucalyptus stands and the remaining pastures). Composition, species richness and insect abundance in each habitat type was estimated by sampling the flower heads for each species of host plant, collected by four people for 1h. Differences in mean abundance of plant population between habitats and sites were tested by two-way ANOVA. Differences in plant species richness between habitats and sites and effects of habitat, site and host plant richness on insect richness were tested using a generalized linear model with Poisson errors. Within each sampling site, cerrados showed higher species richness of Asteraceae than pastures and eucalyptus stands. There were also significant differences in plant richness among sites. Mean population abundance values were significantly different among habitats, but not among sites. Increased host plant richness led to significant insect species richness. There were no additional significant effects of habitat on insect richness. Therefore, anthropogenic alterations in landscape determined the impoverishment of plant assemblages and therefore of insect assemblages, because of the positive relationship between host plant richness and insect richness.

Comparison of Techniques for Sampling Adult Necrophilous Insects From Pig Carcasses.

PubMed

Cruise, Angela; Hatano, Eduardo; Watson, David W; Schal, Coby

2018-02-06

Studies of the pre-colonization interval and mechanisms driving necrophilous insect ecological succession depend on effective sampling of adult insects and knowledge of their diel and successional activity patterns. The number of insects trapped, their diversity, and diel periodicity were compared with four sampling methods on neonate pigs. Sampling method, time of day and decomposition age of the pigs significantly affected the number of insects sampled from pigs. We also found significant interactions of sampling method and decomposition day, time of sampling and decomposition day. No single method was superior to the other methods during all three decomposition days. Sampling times after noon yielded the largest samples during the first 2 d of decomposition. On day 3 of decomposition however, all sampling times were equally effective. Therefore, to maximize insect collections from neonate pigs, the method used to sample must vary by decomposition day. The suction trap collected the most species-rich samples, but sticky trap samples were the most diverse, when both species richness and evenness were factored into a Shannon diversity index. Repeated sampling during the noon to 18:00 hours period was most effective to obtain the maximum diversity of trapped insects. The integration of multiple sampling techniques would most effectively sample the necrophilous insect community. However, because all four tested methods were deficient at sampling beetle species, future work should focus on optimizing the most promising methods, alone or in combinations, and incorporate hand-collections of beetles. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Population-wide changes in pinyon-juniper woodlands caused by drought in the American Southwest: Effects on structure, composition, and distribution

Treesearch

John D. Shaw

2006-01-01

A complex of drought, insects, and disease caused widespread mortality in the pinyon-juniper forest types of the American Southwest in recent years. Data from 14,929 plots spanning 25 years and representing over 25 million hectares were analyzed to characterize effects of drought-related mortality on the structure, composition, and distribution of pinyon and juniper...