Comments on the association of immatures of Hemerodromia (Diptera, Empididae) and Simulium (Diptera, Simuliidae), and first record of this association in the Atlantic Forest (Brazil).

PubMed

Sánchez Molina, Óscar; Gil-Azevedo, Leonardo Henrique

2016-11-01

Larvae of Empididae (Diptera) prey on black fly immatures and its pupae can be collected from pupal cases of Simuliidae (Diptera). The aim of our work was to report the second record of association between immatures of Empididae and Simuliidae in the Neotropical Region and the first for the Atlantic Forest (Rio de Janeiro, Brazil). We collected 4982 pupae and exuviae of Simulium Latreille, (Diptera, Simuliidae) and found three with a pupa of Hemerodromia Meigen (Diptera, Empididae) inside. This shows that the use of black flies cocoons by dance flies occurs at extremely low frequencies, which might explain why this association is so rarely recorded. Our results are relevant for a better comprehension of the predator-prey relationship between these families. Copyright © 2016 Elsevier B.V. All rights reserved.

Parental care compromises feeding in the pumpkinseed ( Lepomis gibbosus)

NASA Astrophysics Data System (ADS)

Zięba, G.; Dukowska, M.; Przybylski, M.; Fox, M. G.; Smith, C.

2018-04-01

Providing parental care is potentially costly. Costs can arise through elevated energy expenditure or from an increased risk of mortality. A cost of parental care can also occur because a parent is compromised in their ability to forage. We used pumpkinseed Lepomis gibbosus, a fish with an alternative male mating strategy, to test whether parental males differed in their feeding in comparison with females and cuckolder males. To address this question, we examined the stomach contents of female, cuckolder male, and parental male pumpkinseed during the breeding season over an entire diel cycle. We showed that parental males had a lower total weight of food in their stomachs in comparison with females, while cuckolder males did not. Parental males also had a lower weight and number of chironomids in their stomachs. The temporal pattern of feeding of parental males diverged from that of females, and they had a lower probability of pupal chironomids in their stomachs, which implies spatial segregation in foraging. Parental males had a greater probability of conspecific eggs in their stomachs than females, while the probability of egg cannibalism did not differ between cuckolder males and females. Overall, these finding meet predictions in accordance with an assumption that parental care and territoriality can compromise feeding.

Efficient isolation method for high-quality genomic DNA from cicada exuviae.

PubMed

Nguyen, Hoa Quynh; Kim, Ye Inn; Borzée, Amaël; Jang, Yikweon

2017-10-01

In recent years, animal ethics issues have led researchers to explore nondestructive methods to access materials for genetic studies. Cicada exuviae are among those materials because they are cast skins that individuals left after molt and are easily collected. In this study, we aim to identify the most efficient extraction method to obtain high quantity and quality of DNA from cicada exuviae. We compared relative DNA yield and purity of six extraction protocols, including both manual protocols and available commercial kits, extracting from four different exoskeleton parts. Furthermore, amplification and sequencing of genomic DNA were evaluated in terms of availability of sequencing sequence at the expected genomic size. Both the choice of protocol and exuvia part significantly affected DNA yield and purity. Only samples that were extracted using the PowerSoil DNA Isolation kit generated gel bands of expected size as well as successful sequencing results. The failed attempts to extract DNA using other protocols could be partially explained by a low DNA yield from cicada exuviae and partly by contamination with humic acids that exist in the soil where cicada nymphs reside before emergence, as shown by spectroscopic measurements. Genomic DNA extracted from cicada exuviae could provide valuable information for species identification, allowing the investigation of genetic diversity across consecutive broods, or spatiotemporal variation among various populations. Consequently, we hope to provide a simple method to acquire pure genomic DNA applicable for multiple research purposes.

Analysis of functions of the chitin deacetylase gene family in Tribolium castaneum.

PubMed

Arakane, Yasuyuki; Dixit, Radhika; Begum, Khurshida; Park, Yoonseong; Specht, Charles A; Merzendorfer, Hans; Kramer, Karl J; Muthukrishnan, Subbaratnam; Beeman, Richard W

2009-01-01

The expression profiles of nine genes encoding chitin deacetylase (CDA)-like proteins were studied during development and in various tissues of the red flour beetle, Tribolium castaneum, by RT-PCR. TcCDA1, TcCDA2 and TcCDA5 were expressed throughout all stages of development, while TcCDA6-9 were expressed predominantly during larval feeding stages. In situ hybridization experiments revealed that both TcCDA1 and TcCDA2 were expressed in epidermal cells. Polyclonal antibody to TcCDA1 detected an immunoreactive protein in larval tracheae. TcCDA6 through TcCDA9, which belong to a distinct subgroup of gut-specific CDAs, were transcribed in the cells lining the midgut, including epithelial cells. TcCDA3 was expressed in the thoracic muscles, whereas TcCDA4 was expressed in early imaginal appendages. To study the function(s) of individual TcCDA genes, double-stranded RNAs (dsRNA) specific for each gene were injected into insects at different developmental stages and the phenotypes were monitored. No visible phenotypic changes were observed after injection of dsRNAs for TcCDA3 to 9, whereas injection of dsRNAs for TcCDA1 or TcCDA2 affected all types of molts, including larval-larval, larval-pupal and pupal-adult. Insects treated with these dsRNAs could not shed the old cuticle and were trapped in their exuviae. Interestingly, unique and very dissimilar adult phenotypes were observed after injection of dsRNAs that specifically down-regulated either of the two alternatively spliced transcripts of TcCDA2, namely TcCDA2a or TcCDA2b. These results reveal functional specialization among T. castaneum CDA genes and splice variants.

Excretion of cadmium and zinc during moulting in the grasshopper Omocestus viridulus (Orthoptera)

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

Lindqvist, L.; Block, M.

1994-10-01

Nymphs of Omocestus viridulus (Orthoptera) were reared on grass leaves containing known amounts of [sup 109]Cd or [sup 65]Zn. After the animals molted to adults, contents of these metals were measured in the grasshoppers, in the cast of exuviae and in the feces produced during rearing. Dry weights of adult bodies and exuviae were lower for [sup 109]Cd-treated grasshoppers than for those given [sup 65]Zn. Exuviae accounted for only a minor part of the excreted [sup 109]Cd and [sup 65]Zn. The [sup 109]Cd was assimilated from food to a much smaller extent than was [sup 65]Zn. After 15 d ofmore » rearing, [approximately] 50% of the ingested [sup 65]Zn, but only 10% of the ingested [sup 109]Cd, remained in the grasshoppers. Because the amount of [sup 109]Cd in the grasshopper nymphs decreased with time, whereas that of the exuviae were constant, content in exuviae constituted a larger portion of the total content of [sup 109]Cd with increasing time between feeding of [sup 109]Cd and molting. For [sup 65]Zn there was no such trend.« less

[Inhibitory effect of turpentine oil on Aedes aegypti (Diptera:Culicidae) larvae growth].

PubMed

Leyva Silva, Maureen; Marquetti Fernández, Maria del Carmen; Tacoronte González, Juan E; Tiomno Tiomnovay, Olinka; Montada Dorta, Domingo

2010-01-01

in the fight for environmental protection, finding out alternative ways to control vectors that are important from the medical viewpoint is a must. Those plants having potent active principles and high chemical stability to act as pesticides can contribute to this end. to evaluate the possible inhibitory effect of photochemically-modified turpentine oil on Aedes aegypti larvae growth. Aedes aegypti larvae of an insecticide-sensitive strain from the insect breeding site located in the Institute of Tropical Medicine were used. During a week after the exposure to the lethal dose causing 90% mortality, the mortality indexes of larvae and pupas were recorded as well as the number of emerged adults and their sex in addition to adults stuck to the exuvias. high larval and pupal mortality was observed in the survivors to the lethal dose causing 90% mortality after one week of the exposure; mortality index was 39.46%. Larvae which managed to grow to become adults amounted to 60.54% of the surviving larvae. Female to male ratio was very similar in the control whereas the exposed group showed a higher number of male adults. On estimating the hatching inhibition percentage, it got 36.47%. the activity of turpentine oil as larvicide and Ae. aegypti growth inhibitor was demonstrated.

Disturbance caused by freshwater releases of different magnitude on the aquatic macroinvertebrate communities of two coastal lagoons

NASA Astrophysics Data System (ADS)

Cañedo-Argüelles, Miguel; Rieradevall, Maria

2010-06-01

The response of the aquatic macroinvertebrate communities to freshwater releases of different magnitude and persistence was investigated in two Mediterranean coastal lagoons (Ca l'Arana and Ricarda). The study was carried out during 14 months (June 2004-July 2005) in which different environmental variables and the macroinvertebrate communities associated with two different habitats, the Phragmites australis belt and the deep area of the lagoons, were sampled monthly. Additionally, potential colonizing sources were identified through the analysis of Chironomidae pupal exuviae. The initial response of the communities to the freshwater releases was similar, being characterized by a peak of opportunistic taxa (mainly Naididae), but the late response was different for each lagoon. In the Ca l'Arana, the magnitude of the freshwater release was higher (salinity dropped below five, which is the limit commonly established for most freshwater species) and its persistence was also higher, allowing the colonization of the lagoon by new insect taxa, which replaced the brackish water species. In the Ricarda, the salinity never dropped beyond five and pre-disturbance conditions were rapidly re-established. This, together with the acclimatizing mechanisms showed by the species Chironomus riparius and Hediste diversicolor, permitted the recovery of the pre-disturbance macroinvertebrate community.

Fossil chironomid d13C as a new proxy for past methanogenic contribution to benthic food-webs in lakes?

NASA Astrophysics Data System (ADS)

van Hardenbroek, M.; Heiri, O. M.; Grey, J.; Bodelier, P. L. E.; Lotter, A. F.

2009-04-01

Lake sediments are an important source of atmospheric methane. Methanogenic archaea in lake sediments produce 13C-depleted methane that is partly released to the water column and the atmosphere. Another part is utilized by methane oxidizing bacteria (MOB) that are an important food source for deposit-feeding chironomid larvae (Diptera: Chironomidae). If methane-derived carbon is a significant component of the chironomid diet this will lead to strongly negative d13C in the tissue and exoskeleton of chironomid larvae. Chironomid cuticles, especially the strongly sclerotized head capsules, are well preserved as fossils in lake sediments. If the relationship between modern methane fluxes in lakes and chironomid d13C can be established this would therefore provide an approach for estimating past methane fluxes based on d13C of fossil chironomid remains. Using culturing experiments we show that the stable carbon isotope signature of MOB and other food sources can be traced in chironomid muscle tissue as well as in the fossilizing exoskeleton. In addition we measured d13C in chironomid larval head capsules and other invertebrate remains from a range of surface and downcore sediment samples. Small intra-specific variability (-27.1 ± 0.08 permille) was measured in replicate samples of chironomid head capsules of Corynocera ambigua (n=7). d13C of chironomid head capsules from a several different taxa ranged from -28.0 to -25.8 permille, but in some instances we observed d13C values as low as -36.9 to -31.5 permille, suggesting that carbon from MOB can be successfully traced in fossil and subfossil chironomid remains. Our results demonstrate that the stable carbon isotope signature of MOB is incorporated into chironomid head capsules. Future research will focus on quantifying the relationship between methane fluxes, MOB, and head capsule d13C in order to reconstruct past methane fluxes based on the lake sediment record.

New Records and Range Extensions for Several Chironomid Genera from Lake Superior

EPA Science Inventory

Five genera of chironomids have been reported for the first time in Lake Superior. Chironomids are small flying insects with a sediment-dwelling aquatic larval stage. The chironomids were collected by scientists at the Mid-Continent Ecology Division as part of a research program ...

Oxygen Isotopes Archived in Subfossil Chironomids: Advancing a Promising Proxy for Lake Water Isotopes

NASA Astrophysics Data System (ADS)

Lasher, G. E.; Axford, Y.; Blair, N. E.

2017-12-01

Oxygen isotopes measured in subfossil chironomid head capsules (aquatic insect remains) in lake sediments are beginning to offer paleoclimate insights from previously under-studied areas of the world. Since the first published pilot study demonstrated the potential of chironomid δ18O to record lake water δ18O (Wooller et al., 2004), subsequent work has refined our understanding of this proxy: confirming via lab cultures that growth water controls head capsule δ18O (Wang et al., 2009), refining laboratory pretreatment protocols, and further validating the method by demonstrating strong agreement between carbonate and chironomid-derived paleo-isotope records (Verbruggen et al., 2009, 2010, 2011). However, outstanding questions remain, including the seasonality of chironomid growth, possible species-dependent vital effects, and diagenetic effects on the protein-chitin complex that comprise chironomid cuticles. To address some of these questions, we summarize available data from paired modern chironomid-lake water δ18O values from around the world and discuss climatic and environmental factors affecting chironomid isotopic signatures. We also present new data on the resistance of these subfossils to diagenesis and degradation throughout the late Quaternary using Fourier Transform Infrared Spectroscopy (FT-IR) and Pyrolysis Gas Chromatography Mass Spectrometry (Py-GC/MS) of chironomid remains up to >100,000 years old. As chironomids are nearly ubiquitous in lakes globally and, we argue, molecularly stable through glacial and interglacial cycles, this proxy has the potential to greatly expand the spatial and temporal resolution of Quaternary paleo-isotopes and thus climate records. In addition to reviewing and presenting new methodological advances, we also present applications of chironomid δ18O from millennial- to centennial-scale Holocene Greenland lake records.

Out with the garbage: the parasitic strategy of the mantisfly Plega hagenella mass-infesting colonies of the eusocial bee Melipona subnitida in northeastern Brazil.

PubMed

Maia-Silva, Camila; Hrncir, Michael; Koedam, Dirk; Machado, Renato Jose Pires; Imperatriz-Fonseca, Vera Lucia

2013-01-01

Between April and June of 2012 mantisflies (Plega hagenella) were found to be extensively parasitizing the nests of two groups of managed colonzies of eusocial stingless bees (Melipona subnitida) in the semi-arid region of northeastern Brazil. The mantisfly larvae developed inside closed brood cells of the bee comb, where each mantispid larva fed on the bee larva or pupa present in a single brood cell. Mature mantispid larvae pupated inside silken cocoons spun in place within their hosts' brood cells then emerged as pharate adults inside the bee colony. Pharate adults were never attacked and killed by host colony workers. Instead, colony workers picked up the pharates and removed them from the nest unharmed, treating them similar to the way that the general refuse is removed from the nest. Adult mantispids subsequently eclosed from their pupal exuviae outside the nest. Manipulative experiments showed that post-eclosion adult mantispids placed back within active bee colonies were quickly attacked and killed. These observations demonstrate that pharate and post-eclosion adults of P. hagenella are perceived differently by colony workers and that delayed adult eclosion is an important functional element in the parasitic life strategy of P. hagenella, allowing adults to escape without injury from the bee colonies they parasitize.

Out with the garbage: the parasitic strategy of the mantisfly Plega hagenella mass-infesting colonies of the eusocial bee Melipona subnitida in northeastern Brazil

NASA Astrophysics Data System (ADS)

Maia-Silva, Camila; Hrncir, Michael; Koedam, Dirk; Machado, Renato Jose Pires; Imperatriz-Fonseca, Vera Lucia

2013-01-01

Between April and June of 2012 mantisflies ( Plega hagenella) were found to be extensively parasitizing the nests of two groups of managed colonzies of eusocial stingless bees ( Melipona subnitida) in the semi-arid region of northeastern Brazil. The mantisfly larvae developed inside closed brood cells of the bee comb, where each mantispid larva fed on the bee larva or pupa present in a single brood cell. Mature mantispid larvae pupated inside silken cocoons spun in place within their hosts' brood cells then emerged as pharate adults inside the bee colony. Pharate adults were never attacked and killed by host colony workers. Instead, colony workers picked up the pharates and removed them from the nest unharmed, treating them similar to the way that the general refuse is removed from the nest. Adult mantispids subsequently eclosed from their pupal exuviae outside the nest. Manipulative experiments showed that post-eclosion adult mantispids placed back within active bee colonies were quickly attacked and killed. These observations demonstrate that pharate and post-eclosion adults of P. hagenella are perceived differently by colony workers and that delayed adult eclosion is an important functional element in the parasitic life strategy of P. hagenella, allowing adults to escape without injury from the bee colonies they parasitize.

Allergy to chironomid larvae (red migde larvae) in non professional handlers of fish food.

PubMed

Cabrerizo Ballesteros, S; de Barrio, M; Baeza, M L; Rubio Sotés, M

2006-01-01

Chironomids are insects which inhabit wetlands. In countries such as Sudan, The United States. Egypt and Japan they are the cause of serious environmental allergy. In Europe, and particularly in Spain, allergy to Chironomids is infrequent and has only been described in patients who handle Chironomid larvae which form part of certain fish foods. We report a case of hypersensitivity to the Chironomid Midge (Chironomus thummi thummi) in a 23-year-old patient who on two occasions, after being in contact with fishfood, suffered rash, rhinoconjunctivitis, dyspnea and dysphagia. A Prick test was carried out with the habitual pneumoallergens, Chironomid Midge extract (PBS: 1.3 mg/ml), Common Mosquito (Culex pipiens), Squid, Mussel, Prawn and Anisakis. Conjunctival provocation was also carried out with Chironomid Midge extract; detection of specific IgE for Chironomid Midge, Common Mosquito (Aedes comunis), Mussel, Squid, Shrimp, Anisakis, house dust and house mites by means of the CAP technique; detection of IgE by means of ELISA in response to Chironomid Midge, Aedes mosquito, Squid, Prawn, Mussel and Anisakis; ELISA-inhibition and Immunoblott-inhibition. The positive results of the cutaneous tests, the detection of specific IgE and conjunctival provocation confirmed the existence of an IgE-mediated mechanism. In our patient, the in vitro techniques demonstrated cross reactivity with the Common Mosquito. We report on a patient with a case history of rhinoconjunctivitis, rash, dyspnea, and dysphagia after handling fish food. The etiological agent was the Chironomid larvae. The sensitization of our patient has been demonstrated by means of in vivo and in vitro techniques.

[Toxicity and influencing factors of liquid chlorine on chironomid larvae].

PubMed

Sun, Xing-Bin; Cui, Fu-Yi; Zhang, Jin-Song; Guo, Zhao-Hai; Xu, Feng; Liu, Li-Jun

2005-09-01

The excessive propagation of Chironomid larvae (red worm) in the sedimentation tanks is a difficult problem for the normal function of waterworks. The toxic effect of liquid chlorine on the different instar larvae of Chironomid was studied using distilled water as test sample. Furthermore, the effect of pH value, organic matter content, ammonia nitrogen, and algae content on toxicity of liquid chlorine was observed. The results show that the tolerance of Chironomid larvae to liquid chlorine is strengthened with the increase in instar. The 24h semi-lethal concentration (LC50) of liquid chlorine to the 4th instar larvae of Chironomid is 3.39 mg/L. Low pH value and high algae content are helpful to improve the toxic effect of liquid chlorine to Chironomid larvae. In neutral water body, the increase in organic matter content results in the decrease in the death rate of Chironomid larvae. The toxicity of liquid chlorine differs greatly in different concentrations of ammonia nitrogen. The death rate of the 4th instar larvae of Chironomid in raw water is higher by contrast with that in sedimentation tanks water for 24h disposal with various amount of liquid chlorine.

The role of pH in structuring communities of Maine wetland macrophytes and chironomid larvae (Diptera)

USGS Publications Warehouse

Woodcock, T.S.; Longcore, J.R.; McAuley, D.G.; Mingo, T.M.; Bennatti, C.R.; Stromborg, K.L.

2005-01-01

Aquatic vascular plants, or macrophytes, are an important habitat component for many wetland organisms, and larvae of chironomid midges are ubiquitous components of wetland fauna. Many chironomids are primary consumers of algae and detritus and form an essential energetic link between allochthonous and autochthonous primary production and higher trophic levels, while others are predators and feed on smaller invertebrates. Live macrophytes serve mostly as habitat, whereas plant detritus serves as both habitat and as a food source. Assemblages of macrophytes and chironomid larvae were surveyed in ten Maine wetlands, five with low pH (5.5), and explained in terms of physical and chemical habitat variables. Macrophyte richness was significantly greater, and richness of chironomid larvae was lower, in low pH wetlands. There was no difference in chironomid abundance related to pH. However, community structure was related to pH, suggesting that competitive dominance of a few taxa was responsible for lower richness in low pH wetlands, whereas competition was weaker in high pH wetlands, making coexistence of more chironomid taxa possible. An examination of individual chironomid taxa by stepwise multiple regression showed that distribution of most taxa was controlled by water chemistry variables and macrophyte habit (i.e., floating, submergent).

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

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

Sieve efficiency in benthic sampling as related to chironomid head capsule width

USGS Publications Warehouse

Hudson, Patrick L.; Adams, Jean V.

1998-01-01

The width of the head capsule in chironomid larvae is the most important morphometric character controlling retention of specimens in sieving devices. Knowledge of the range in size of these widths within any chironomid community is fundamental to sampling and interpreting the resulting data. We present the head capsule widths of 30 species of chironomids and relate their size distribution to loss or retention in several experiments using graded sieve sizes. Based on our measurements and those found in the literature we found the head capsule width of fourth instars in half the chironomids species to be less than 350 I?m. Many species may never be collected with the commonly used U.S. Standard No. 30 sieve (589 I?m), and the No. 60 (246 I?m) screen appears to retain most species only qualitatively. We found 70 to 90% of the chironomid larvae and 19 to 34% of their biomass can pass through a No. 80 sieve (177 I?m). The implications of sieve loss and other factors affecting sieving efficiency are discussed.

Northern Russian chironomid-based modern summer temperature data set and inference models

NASA Astrophysics Data System (ADS)

Nazarova, Larisa; Self, Angela E.; Brooks, Stephen J.; van Hardenbroek, Maarten; Herzschuh, Ulrike; Diekmann, Bernhard

2015-11-01

West and East Siberian data sets and 55 new sites were merged based on the high taxonomic similarity, and the strong relationship between mean July air temperature and the distribution of chironomid taxa in both data sets compared with other environmental parameters. Multivariate statistical analysis of chironomid and environmental data from the combined data set consisting of 268 lakes, located in northern Russia, suggests that mean July air temperature explains the greatest amount of variance in chironomid distribution compared with other measured variables (latitude, longitude, altitude, water depth, lake surface area, pH, conductivity, mean January air temperature, mean July air temperature, and continentality). We established two robust inference models to reconstruct mean summer air temperatures from subfossil chironomids based on ecological and geographical approaches. The North Russian 2-component WA-PLS model (RMSEPJack = 1.35 °C, rJack2 = 0.87) can be recommended for application in palaeoclimatic studies in northern Russia. Based on distinctive chironomid fauna and climatic regimes of Kamchatka the Far East 2-component WAPLS model (RMSEPJack = 1.3 °C, rJack2 = 0.81) has potentially better applicability in Kamchatka.

Seasonality and weather conditions jointly drive flight activity patterns of aquatic and terrestrial chironomids.

PubMed

Vebrová, Lucie; van Nieuwenhuijzen, Andre; Kolář, Vojtěch; Boukal, David S

2018-06-19

Chironomids, a major invertebrate taxon in many standing freshwaters, rely on adult flight to reach new suitable sites, yet the impact of weather conditions on their flight activity is little understood. We investigated diel and seasonal flight activity patterns of aquatic and terrestrial chironomids in a reclaimed sandpit area and analysed how weather conditions and seasonality influenced their total abundance and species composition. Air temperature, relative humidity, wind speed, and air pressure significantly affected total flight activity of both groups, but not in the same way. We identified an intermediate temperature and humidity optimum for the flight activity of terrestrial chironomids, which contrasted with weaker, timescale-dependent relationships in aquatic species. Flight activity of both groups further declined with wind speed and increased with air pressure. Observed flight patterns also varied in time on both daily and seasonal scale. Flight activity of both groups peaked in the evenings after accounting for weather conditions but, surprisingly, aquatic and terrestrial chironomids used partly alternating time windows for dispersal during the season. This may be driven by different seasonal trends of key environmental variables in larval habitats and hence implies that species phenologies and conditions experienced by chironomid larvae (and probably other aquatic insects with short-lived adults) influence adult flight patterns more than weather conditions. Our results provide detailed insights into the drivers of chironomid flight activity and highlight the methodological challenges arising from the inherent collinearity of weather characteristics and their diurnal and seasonal cycles.

Common antigenic determinants of haemoglobin as basis of immunological cross-reactivity between chironomid species (Diptera, Chironomidae): studies with human and animal sera.

PubMed Central

Baur, X; Dewair, M; Haegele, K; Prelicz, H; Scholl, A; Tichy, H

1983-01-01

Chironomids, of which approximately 10,000 species exist, are reported to cause severe immediate type allergic diseases in man. In the present study, immunological cross-reactivity between 14 chironomid species from different continents was proven by RAST inhibition, double immunodiffusion and a new allergoprint technique, based upon PAGE separation of insect crude extracts. Using isolated chironomid haemoglobins and sera of sensitized persons, as well as rabbit antibodies against larval crude extract or against the haemoglobin fraction of Chironomus thummi, it could be proven that cross-reactivity derives at least predominantly from haemoglobin components with common antigenic determinants in the different species. Images Fig. 2 Fig. 7 Fig. 8 Fig. 9 PMID:6197219

Quaternary paleoecology of aquatic Diptera in tropical and Southern Hemisphere regions, with special reference to the Chironomidae

NASA Astrophysics Data System (ADS)

Verschuren, Dirk; Eggermont, Hilde

2006-08-01

Chironomid paleoecology in north-temperate regions has made tremendous progress over the past decade, but studies in tropical and Southern Hemisphere regions remain relatively scarce. Reasons for this imbalance are (1) incomplete taxonomic knowledge of chironomid faunas outside Europe and North America, (2) a scarcity of ecological data on local species and genera that might confer bio-indicator value to them, and (3) logistic difficulties hampering the lake surveying necessary to develop paleoenvironmental calibration data sets. Thus far, most chironomid paleoecology in tropical and Southern Hemisphere regions has relied on an indicator-species approach, combining autecological information on local species of which larval morphology is known with the traditional ecological typology of chironomid genera transferred from the Holarctic region. This paper reviews work accomplished to date in tropical and temperate South America, Australia, Africa, and New Zealand, including studies on various families of non-chironomid Diptera with diagnostic fossils. Research has focused mostly on late-Glacial and Holocene climate reconstruction, less on tracing past human disturbance of aquatic ecosystems and their drainage basins. Quantitative chironomid-based paleoenvironmental reconstruction has so far been done only in Australia and Africa. These studies compensated for the lack of traditional surface-sediment calibration data sets, nowadays often the main source of quantitative information on species ecological optima and tolerances, by maximally exploiting archival species-distribution data based on live collections of adult and/or larval midges. This stimulated efforts to achieve trustworthy species-level identification of fossil chironomid remains, and, as a result, the taxonomic resolution of paleoecological studies in Australia and Africa is higher on average than that achieved in European and North American studies.

Survival of Salmonella enterica in Freshwater and Sediments and Transmission by the Aquatic Midge Chironomus tentans (Chironomidae: Diptera)

PubMed Central

Moore, Barry C.; Martinez, Edward; Gay, John M.; Rice, Daniel H.

2003-01-01

Survival of a nalidixic acid-resistant strain of Salmonella enterica serovar Typhimurium mr-DT-104 in water and sediments was tested using artificially contaminated aquaria. Water samples remained culture positive for salmonella for up to 54 days. Sediment samples were culture positive up to 119 days. In addition, potential mechanisms for spreading salmonella in the environments by chironomid larvae and adults were tested. We evaluated the acquisition of mr-DT-104 by chironomids from contaminated aquatic sediments and subsequent spread to uncontaminated sediments. Larval chironomids raised in contaminated sediments became culture positive, and the bacteria were carried over to adults after emergence. Contamination of clean sediments by chironomid larvae was not demonstrated. These findings clearly suggest that mr-DT-104 serovar organisms can survive in aquatic sediments for at least several months. Uptake of salmonellae by chironomid larvae and adults suggests that they are possible vectors of mr-DT-104 in both aquatic and terrestrial environments, although the role of larval defecation in movement of bacteria to new sediments was not demonstrated. PMID:12902242

Annual Survey of Horsehair Worm Cysts in Northern Taiwan, with Notes on a Single Seasonal Infection Peak in Chironomid Larvae (Diptera: Chironomidae).

PubMed

Chiu, Ming-Chung; Huang, Chin-Gi; Wu, Wen-Jer; Shiao, Shiuh-Feng

2016-06-01

The life cycle of the freshwater horsehair worm typically includes a free-living phase (adult, egg, larva) and a multiple-host parasitic phase (aquatic paratenic host, terrestrial definitive host). Such a life cycle involving water and land can improve energy flow in riparian ecosystems; however, its temporal dynamics in nature have rarely been investigated. This study examined seasonal infection with cysts in larval Chironominae (Diptera: Chironomidae) in northern Taiwan. In the larval chironomids, cysts of 3 horsehair worm species were identified. The cysts of the dominant species were morphologically similar to those of Chordodes formosanus. Infection with these cysts increased suddenly and peaked 2 mo after the reproductive season of the adult horsehair worms. Although adult C. formosanus emerged several times in a year, only 1 distinct infection peak was detected in September in the chironomid larvae. Compared with the subfamily Chironominae, samples from the subfamilies Tanypodinae and Orthocladiinae were less parasitized. This indicates that the feeding behavior of the chironomid host likely affects horsehair worm cyst infections; however, bioconcentration in predatory chironomids was not detected.

Butterfly Wings Are Three-Dimensional: Pupal Cuticle Focal Spots and Their Associated Structures in Junonia Butterflies.

PubMed

Taira, Wataru; Otaki, Joji M

2016-01-01

Butterfly wing color patterns often contain eyespots, which are developmentally determined at the late larval and early pupal stages by organizing activities of focal cells that can later form eyespot foci. In the pupal stage, the focal position of a future eyespot is often marked by a focal spot, one of the pupal cuticle spots, on the pupal surface. Here, we examined the possible relationships of the pupal focal spots with the underneath pupal wing tissues and with the adult wing eyespots using Junonia butterflies. Large pupal focal spots were found in two species with large adult eyespots, J. orithya and J. almana, whereas only small pupal focal spots were found in a species with small adult eyespots, J. hedonia. The size of five pupal focal spots on a single wing was correlated with the size of the corresponding adult eyespots in J. orithya. A pupal focal spot was a three-dimensional bulge of cuticle surface, and the underside of the major pupal focal spot exhibited a hollowed cuticle in a pupal case. Cross sections of a pupal wing revealed that the cuticle layer shows a curvature at a focal spot, and a positional correlation was observed between the cuticle layer thickness and its corresponding cell layer thickness. Adult major eyespots of J. orithya and J. almana exhibited surface elevations and depressions that approximately correspond to the coloration within an eyespot. Our results suggest that a pupal focal spot is produced by the organizing activity of focal cells underneath the focal spot. Probably because the focal cell layer immediately underneath a focal spot is thicker than that of its surrounding areas, eyespots of adult butterfly wings are three-dimensionally constructed. The color-height relationship in adult eyespots might have an implication in the developmental signaling for determining the eyespot color patterns.

Butterfly Wings Are Three-Dimensional: Pupal Cuticle Focal Spots and Their Associated Structures in Junonia Butterflies

PubMed Central

Taira, Wataru; Otaki, Joji M.

2016-01-01

Butterfly wing color patterns often contain eyespots, which are developmentally determined at the late larval and early pupal stages by organizing activities of focal cells that can later form eyespot foci. In the pupal stage, the focal position of a future eyespot is often marked by a focal spot, one of the pupal cuticle spots, on the pupal surface. Here, we examined the possible relationships of the pupal focal spots with the underneath pupal wing tissues and with the adult wing eyespots using Junonia butterflies. Large pupal focal spots were found in two species with large adult eyespots, J. orithya and J. almana, whereas only small pupal focal spots were found in a species with small adult eyespots, J. hedonia. The size of five pupal focal spots on a single wing was correlated with the size of the corresponding adult eyespots in J. orithya. A pupal focal spot was a three-dimensional bulge of cuticle surface, and the underside of the major pupal focal spot exhibited a hollowed cuticle in a pupal case. Cross sections of a pupal wing revealed that the cuticle layer shows a curvature at a focal spot, and a positional correlation was observed between the cuticle layer thickness and its corresponding cell layer thickness. Adult major eyespots of J. orithya and J. almana exhibited surface elevations and depressions that approximately correspond to the coloration within an eyespot. Our results suggest that a pupal focal spot is produced by the organizing activity of focal cells underneath the focal spot. Probably because the focal cell layer immediately underneath a focal spot is thicker than that of its surrounding areas, eyespots of adult butterfly wings are three-dimensionally constructed. The color-height relationship in adult eyespots might have an implication in the developmental signaling for determining the eyespot color patterns. PMID:26731532

Chironomid midges (Diptera, chironomidae) show extremely small genome sizes.

PubMed

Cornette, Richard; Gusev, Oleg; Nakahara, Yuichi; Shimura, Sachiko; Kikawada, Takahiro; Okuda, Takashi

2015-06-01

Chironomid midges (Diptera; Chironomidae) are found in various environments from the high Arctic to the Antarctic, including temperate and tropical regions. In many freshwater habitats, members of this family are among the most abundant invertebrates. In the present study, the genome sizes of 25 chironomid species were determined by flow cytometry and the resulting C-values ranged from 0.07 to 0.20 pg DNA (i.e. from about 68 to 195 Mbp). These genome sizes were uniformly very small and included, to our knowledge, the smallest genome sizes recorded to date among insects. Small proportion of transposable elements and short intron sizes were suggested to contribute to the reduction of genome sizes in chironomids. We discuss about the possible developmental and physiological advantages of having a small genome size and about putative implications for the ecological success of the family Chironomidae.

Patterns in Benthic Biodiversity Link Lake Trophic Status to Structure and Potential Function of Three Large, Deep Lakes

PubMed Central

Hayford, Barbara L.; Caires, Andrea M.; Chandra, Sudeep; Girdner, Scott F.

2015-01-01

Relative to their scarcity, large, deep lakes support a large proportion of the world’s freshwater species. This biodiversity is threatened by human development and is in need of conservation. Direct comparison of biodiversity is the basis of biological monitoring for conservation but is difficult to conduct between large, insular ecosystems. The objective of our study was to conduct such a comparison of benthic biodiversity between three of the world’s largest lakes: Lake Tahoe, USA; Lake Hövsgöl, Mongolia; and Crater Lake, USA. We examined biodiversity of common benthic organism, the non-biting midges (Chironomidae) and determined lake trophic status using chironomid-based lake typology, tested whether community structure was similar between the three lakes despite geographic distance; and tested whether chironomid diversity would show significant variation within and between lakes. Typology analysis indicated that Lake Hövsgöl was ultra-oligotrophic, Crater Lake was oligotrophic, and Lake Tahoe was borderline oligotrophic/mesotrophic. These results were similar to traditional pelagic measures of lake trophic status for Lake Hövsgöl and Crater Lake but differed for Lake Tahoe, which has been designated as ultra-oligotrophic by traditional pelagic measures such as transparency found in the literature. Analysis of similarity showed that Lake Tahoe and Lake Hövsgöl chironomid communities were more similar to each other than either was to Crater Lake communities. Diversity varied between the three lakes and spatially within each lake. This research shows that chironomid communities from these large lakes were sensitive to trophic conditions. Chironomid communities were similar between the deep environments of Lake Hövsgöl and Lake Tahoe, indicating that chironomid communities from these lakes may be useful in comparing trophic state changes in large lakes. Spatial variation in Lake Tahoe’s diversity is indicative of differential response of chironomid communities to nutrient enrichment which may be an indication of changes in trophic state within and across habitats. PMID:25594516

RNA interference of chitin synthase genes inhibits chitin biosynthesis and affects larval performance in Leptinotarsa decemlineata (Say).

PubMed

Shi, Ji-Feng; Mu, Li-Li; Chen, Xu; Guo, Wen-Chao; Li, Guo-Qing

2016-01-01

Dietary introduction of bacterially expressed double-stranded RNA (dsRNA) has great potential for management of Leptinotarsa decemlineata . Identification of the most attractive candidate genes for RNA interference (RNAi) is the first step. In the present paper, three complete chitin synthase cDNA sequences ( LdChSAa , LdChSAb and LdChSB ) were cloned. LdChSAa and LdChSAb , two splicing variants of LdChSA gene, were highly expressed in ectodermally-derived epidermal cells forming epidermis, trachea, foregut and hindgut, whereas LdChSB was mainly transcribed in midgut cells. Feeding bacterially expressed ds ChSA (derived from a common fragment of LdChSAa and LdChSAb ), ds ChSAa , ds ChSAb and ds ChSB in the second- and fourth-instar larvae specifically knocked down their target mRNAs. RNAi of LdChSAa + LdChSAb and LdChSAa lowered chitin contents in whole body and integument samples, and thinned tracheal taenidia. The resulting larvae failed to ecdyse, pupate, or emerge as adults. Comparably, knockdown of LdChSAb mainly affected pupal-adult molting. The LdChSAb RNAi pupae did not completely shed the old larval exuviae, which caused failure of adult emergence. In contrast, silencing of LdChSB significantly reduced foliage consumption, decreased chitin content in midgut sample, damaged midgut peritrophic matrix, and retarded larval growth. As a result, the development of the LdChSB RNAi hypomorphs was arrested. Our data reveal that these LdChS s are among the effective candidate genes for an RNAi-based control strategy against L. decemlineata .

Wing geometry of Culex coronator (Diptera: Culicidae) from South and Southeast Brazil

PubMed Central

2014-01-01

Background The Coronator Group encompasses Culex coronator Dyar & Knab, Culex camposi Dyar, Culex covagarciai Forattini, Culex ousqua Dyar, Culex usquatissimus Dyar, Culex usquatus Dyar and Culex yojoae Strickman. Culex coronator has the largest geographic distribution, occurring in North, Central and South America. Moreover, it is a potential vector-borne mosquito species because females have been found naturally infected with several arboviruses, i.e., Saint Louis Encephalitis Virus, Venezuelan Equine Encephalitis Virus and West Nile Virus. Considering the epidemiological importance of Cx. coronator, we investigated the wing shape diversity of Cx. coronator from South and Southeast Brazil, a method to preliminarily estimate population diversity. Methods Field-collected immature stages of seven populations from a large geographical area in Brazil were maintained in the laboratory to obtain both females and males linked with pupal and/or larval exuviae. For each individual female, 18 landmarks of left wings were marked and digitalized. After Procrustes superimposition, discriminant analysis of shape was employed to quantify wing shape variation among populations. The isometric estimator centroid size was calculated to assess the overall wing size and allometry. Results Wing shape was polymorphic among populations of Cx. coronator. However, dissimilarities among populations were higher than those observed within each population, suggesting populational differentiation in Cx. coronator. Morphological distances between populations were not correlated to geographical distances, indicating that other factors may act on wing shape and thus, determining microevolutionary patterns in Cx. coronator. Despite the population differentiation, intrapopulational wing shape variability was equivalent among all seven populations. Conclusion The wing variability found in Cx. coronator populations brings to light a new biological problem to be investigated: the population genetics of Cx. coronator. Because of differences in the male genitalia, we also transferred Cx. yojoae to the Apicinus Subgroup. PMID:24721508

Convergent evolution of neuroendocrine control of phenotypic plasticity in pupal colour in butterflies

PubMed Central

Starnecker, G.; Hazel, W.

1999-01-01

Phenotypic plasticity in pupal colour occurs in three families of butterflies (the Nymphalidae, Papilionidae and Pieridae), typically in species whose pupation sites vary unpredictably in colour. In all species studied to date, larvae ready for pupation respond to environmental cues associated with the colour of their pupation sites and moult into cryptic light (yellow–green) or dark (brown–black) pupae. In nymphalids and pierids, pupal colour is controlled by a neuroendocrine factor, pupal melanization-reducing factor (PMRF), the release of which inhibits the melanization of the pupal cuticle resulting in light pupae. In contrast, the neuroendocrine factor controlling pupal colour in papilionid butterflies results in the production of brown pupae. PMRF was extracted from the ventral nerve chains of the peacock butterfly Inachis io (Nymphalidae) and black swallowtail butterfly Papilio polyxenes (Papilionidae). When injected into pre-pupae, the extracts resulted in yellow pupae in I. io but brown pupae in P. polyxenes. These results suggest that the same neuroendocrine factor controls the plasticity in pupal colour, but that plasticity in pupal colour in these species has evolved independently (convergently).

The effects of experimental lake acidification on the reproductive success of tree swallows

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

St. Louis, V.L.

1992-01-01

The effects of lake acidification on reproductive success of tree swallows (Tachycineta bicolor) breeding near experimentally acidified and unmanipulated reference lakes at the Experimental Lake Area (ELA) were studied. Tree swallows are aerial insectivores that commonly breed near water and forage on emergent insects. Predictions suggest that avian food abundance and quality may be altered due to acidification. Breeding swallows foraged on chironomids emerging at their nest-site lakes before searching for food elsewhere. Among the calcium-rich items consumed by the swallows, fish bones were most numerous, followed by crayfish exoskeleton, clam shell, and bird eggshell. We found significantly fewer calcium-richmore » items in the stomachs of nestlings from acid lakes than in those from reference lakes. Chironomid species were significantly more abundant in acid lakes, while the Chironominae were less numerous. Biomass of emerging chironomids either increased significantly following acidification, or was not different from that of reference lakes. Concentrations of Al, Ca, Mn, and Zn were on average higher in chironomids from a number of the acid lakes than in chironomids from reference lakes. Calcium concentrations in chironomids from the most acid lake were significantly lower, suggesting that Ca may be difficult to sequester at low pH levels. Hepatic concentrations of metallothioneins in tree swallow nestlings were negatively correlated with pH of the nest-site lake. Additive concentrations of Cu and Zn in the liver were correlated with liver MT concentrations, but Cd was not. Near acidified lakes, eggs were smaller in certain dimensions, hatching success was lower, certain nestling body characters were smaller, nestling wing length was shorter, and growth functions were different than near unmanipulated reference lakes. Clearly even non-aquatic organisms are affected by acidification of freshwater ecosystems.« less

Production dynamics and life cycle of dominant chironomids (diptera, chironomidae) in a subtropical stream in China: adaptation to variable flow conditions in summer and autumn

NASA Astrophysics Data System (ADS)

Yan, Yunjun; Li, Xiaoyu

2007-07-01

The production dynamics and trophic basis of 7 dominant species of chironomids were investigated in the area of a second-order river of the Hanjiang River basin, in central China from June 2003 to June 2004. The results showed that Tvetenia discoloripes was by far the most abundant chironomid, dominating the overall standing stock of the taxa. In terms of lif ecycle, Chaetocladius sp., Eukiefferiella potthasti and T. discoloripes developed 1 generation a year, whereas Microtendipes sp. and Pagastia sp. developed two, while Pentaneura sp. and Polypedilum sp. developed three. T. discoloripes was the most productive chironomid with 120.305 8 g/m2. a, Pentaneura sp. and E. potthasti had relatively high production values of >17 g/m2.a, and the rest were <10 g/m2.a. All the production temporal variation tended to follow biomass patterns. T. discoloripes, Chaetocladius sp. and Pagastia sp. concentrated most of their production in winter, whereas E. potthasti, Pentaneura sp. and Polypedilum sp. had relatively higher production throughout the year. Only Microtendipes sp. had a production that peaked in summer. The overlap in temporal distribution of production among the chironomid species was generally high (>0.5), especially for filter-collectors Microtendipes sp., Chaetocladius sp., Chaetocladius sp., T. discoloripes and Pagastia sp. All species except Pentaneura sp. consumed a large portion of amorphous detritus, constituting more than 90% of their diets, and contributing nearly 90% to their secondary production. All the 7 chironomids represent obvious adaptation to local highly variable climate in summer and autumn in life cycle pattern, production dynamics, and food type.

Changes in carbon sources fueling benthic secondary production over depth and time: coupling Chironomidae stable carbon isotopes to larval abundance.

PubMed

Frossard, Victor; Verneaux, Valérie; Millet, Laurent; Magny, Michel; Perga, Marie-Elodie

2015-06-01

Stable C isotope ratio (δ(13)C) values of chironomid remains (head capsules; HC) were used to infer changes in benthic C sources over the last 150 years for two French sub-Alpine lakes. The HCs were retrieved from a series of sediment cores from different depths. The HC δ(13)C values started to decrease with the onset of eutrophication. The HC δ(13)C temporal patterns varied among depths, which revealed spatial differences in the contribution of methanotrophic bacteria to the benthic secondary production. The estimates of the methane (CH4)-derived C contribution to chironomid biomass ranged from a few percent prior to the 1930s to up to 30 % in recent times. The chironomid fluxes increased concomitantly with changes in HC δ(13)C values before a drastic decrease due to the development of hypoxic conditions. The hypoxia reinforced the implication for CH4-derived C transfer to chironomid production. In Lake Annecy, the HC δ(13)C values were negatively correlated to total organic C (TOC) content in the sediment (Corg), whereas no relationship was found in Lake Bourget. In Lake Bourget, chironomid abundances reached their maximum with TOC contents between 1 and 1.5 % Corg, which could constitute a threshold for change in chironomid abundance and consequently for the integration of CH4-derived C into the lake food webs. Our results indicated that the CH4-derived C contribution to the benthic food webs occurred at different depths in these two large, deep lakes (deep waters and sublittoral zone), and that the trophic transfer of this C was promoted in sublittoral zones where O2 gradients were dynamic.

Silver bioaccumulation in chironomid larvae as a potential source for upper trophic levels: a study case from northern Patagonia.

PubMed

Williams, Natalia; Rizzo, Andrea; Arribére, María A; Suárez, Diego Añón; Guevara, Sergio Ribeiro

2018-01-01

Silver (Ag) is a pollutant of high concern in aquatic ecosystems, considered among the most toxic metallic ions. In lacustrine environments, contaminated sediments are a source of Ag for the food web. Chironomidae (Insecta: Diptera) are the most abundant, diverse, and representative insect groups in aquatic ecosystems. Chironomid larvae are closely associated to benthic substrates and link primary producers and secondary consumers. Given their trophic position and their life habits, these larvae can be considered the entry point for the transference of Ag, from the benthic deposit to the higher trophic levels of the food web. Previous studies in lakes from Nahuel Huapi National Park (Northern Patagonia) showed Ag enrichment over background levels (0.04-0.1 μg g -1 dry weight) both in biota (bivalves and fish liver) and sediments from sites near human settlements. The aim of this study was to analyze the role of chironomids in the transference of Ag from the benthic reservoir of Lake Moreno Oeste to the food web. The concentration of Ag in chironomid larvae tissue ranged from 0.1 to 1.5 μg g -1 dry weight, reaching a bioaccumulation factor up to 17 over substrates and depending on the associated substrate type, feeding habitats, larval stage, and season. The main Ag transfer to higher trophic levels by chironomids occurs in the littoral zone, mostly from larvae inhabiting submerged vegetation (Myriophyllum quitense) and sediment from vegetated zones. This study presents novel evidence of the doorway role played by chironomid larvae in Ag pathways from the sediments into food webs of freshwater ecosystems.

FAMILY CHIRONOMIDAE.

PubMed

Mendes, Humberto Fonseca; Pinho, Luiz Carlos

2016-06-14

Only 30 chironomid species distributed in 16 genera and three subfamilies are formally recorded to Colombia. Another 32 genera and two subfamilies have been recorded on larval stage, with no identification at species level. Many new records, genera and species are expected when focusing on systematics of chironomids from Colombia.

Pupal colour plasticity in a tropical butterfly, Mycalesis mineus (Nymphalidae: Satyrinae).

PubMed

Mayekar, Harshad Vijay; Kodandaramaiah, Ullasa

2017-01-01

Lepidopteran insects have provided excellent study systems for understanding adaptive phenotypic plasticity. Although there are a few well-studied examples of adult plasticity among tropical butterflies, our understanding of plasticity of larval and pupal stages is largely restricted to temperate butterflies. The environmental parameters inducing phenotypic plasticity and the selective pressures acting on phenotypes are likely to differ across tropical and temperate climate regimes. We tested the influence of relative humidity (RH), a prominent yet under-appreciated tropical climatic component, along with pupation substrate, larval development time, pupal sex and weight in determining pupal colour in the tropical satyrine butterfly Mycalesis mineus. Pupae of this butterfly are either brown or green or very rarely intermediate. Larvae were reared at high (85%) and low (60%) RH at a constant temperature. Proportions of green and brown pupae were expected to vary across low and high RH and pupation substrates in order to enhance crypsis. Brown pupae were more common at low RH than at high RH, as predicted, and developed faster than green pupae. Pupal colour was correlated with pupation substrate. Choice of pupation substrate differed across RH treatments. It is unclear whether pupal colour influences substrate selection or whether substrate influences pupal colour. Our study underscores the need for further work to understand the basis of pupal plasticity in tropical butterflies.

miR-11 regulates pupal size of Drosophila melanogaster via directly targeting Ras85D.

PubMed

Li, Yao; Li, Shengjie; Jin, Ping; Chen, Liming; Ma, Fei

2017-01-01

MicroRNAs play diverse roles in various physiological processes during Drosophila development. In the present study, we reported that miR-11 regulates pupal size during Drosophila metamorphosis via targeting Ras85D with the following evidences: pupal size was increased in the miR-11 deletion mutant; restoration of miR-11 in the miR-11 deletion mutant rescued the increased pupal size phenotype observed in the miR-11 deletion mutant; ectopic expression of miR-11 in brain insulin-producing cells (IPCs) and whole body shows consistent alteration of pupal size; Dilps and Ras85D expressions were negatively regulated by miR-11 in vivo; miR-11 targets Ras85D through directly binding to Ras85D 3'-untranslated region in vitro; removal of one copy of Ras85D in the miR-11 deletion mutant rescued the increased pupal size phenotype observed in the miR-11 deletion mutant. Thus, our current work provides a novel mechanism of pupal size determination by microRNAs during Drosophila melanogaster metamorphosis. Copyright © 2017 the American Physiological Society.

An Introduction to the Identification of Chironomid Larvae.

ERIC Educational Resources Information Center

Mason, William T., Jr.

This publication is an introductory guide to the identification of Chironomid (Midge) larvae. The larvae of these small flies are an important link in the food chain between algae and microinvertebrates. As a family, the larvae exhibit a wide range of tolerance to environmental factors such as amounts and types of pollutants. Much of this…

Calcium translocations during the moulting cycle of the semiterrestrial isopod Ligia hawaiiensis (Oniscidea, Crustacea).

PubMed

Ziegler, Andreas; Hagedorn, Monica; Ahearn, Gregory A; Carefoot, Thomas H

2007-01-01

Terrestrial isopods moult first the posterior and then the anterior half of the body. During the moulting cycle they retain a significant fraction of cuticular calcium partly by storing it in sternal CaCO(3) deposits. We analysed the calcium content in whole Ligia hawaiiensis and the calcium distribution between the posterior, the anterior ventral, and the anterior dorsal cuticle during four stages of the moulting cycle. The results indicate that: (1) overall, about 80% of the calcium is retained and 20% is lost with the exuviae, (2) in premoult 68% of the calcium in the posterior cuticle is resorbed (23% moved to the anterior ventral cuticle, 17% to the anterior dorsal cuticle, and the remaining 28% to internal tissues), (3) after the posterior moult 83% of the calcium in the anterior cuticle is shifted to the posterior cuticle and possibly to internal storage sites, (4) following the anterior moult up to 54% of the calcium in the posterior cuticle is resorbed and used to mineralise the new anterior cuticle. (45)Ca-uptake experiments suggest that up to 80% of calcium lost with the anterior exuviae may be regained after its ingestion. Whole body calcium of Ligia hawaiiensis is only 0.7 times that of the fully terrestrial isopods. These terrestrial species can retain only 48% of whole body calcium, suggesting that the amount of calcium that can be retained by shifting it between the anterior and posterior integument is limited. We propose that fully terrestrial Oniscidea rely to a larger degree on other calcium sources like internal stores and uptake from the ingested exuviae.

The sleeping chironomid: an insect survived 18 months of exposure to outer space

NASA Astrophysics Data System (ADS)

Gusev, Oleg; Sakashita, Tetsuya; Sychev, Vladimir; Novikova, Nataliya; Sugimoto, Manabu; Malyutina, Ludmila; Kikawada, Takahiro; Okuda, Takashi

Anhydrobiosis is an ametabolic state of life entered by an organism in response to desiccation. There are only few groups of higher invertebrates capable to survival complete water loss. An African chironomid Polypedilum vanderpalnki is the only anhydrobiotic insect. Larvae of this sleeping chironomid living in temporary pools in semi-arid areas on the African continent become completely desiccated upon drought, but can revive after water becomes available upon the next rain. Dry larvae can revive after several decades of anhydrobiosis and show cross-resistance to different environmental stresses, including temperature fluctuation, high doses of ionizing radiation and organic solvents. This enormous resistance of the sleeping chironomid to extreme environments points to the high probability of their survival and transfer across outer space and makes this species promising model organism for astrobiological studies. In period from 2005 to 2010 the sleeping chironomid was utilized as a model organism in experiments on resistance of resting stages of invertebrates to space environment both inside of ISS ("Aquarium" research program) and on the outer side of ISS ("Biorisk-2" and "EXPOSE-R" experiments) . In the present report we mainly focus on results of "Biorisk-2" experiment where there containers with anhydrobiotic larvae were continuously exposed to outer space environment. Container 1 (FC1) remained exposed to outer space for 405 days (from June 6, 2007 to July 15, 2008), Container 2 (FC2) for 566 days (from June 6, 2007 to December 23, 2008), and Container 3 (FC3) is expected to be returning to the Earth later this year. First analysis of the larvae from the first two containers FC1 and FC2 showed that the sleeping chironomid have succesfully survived the continous space exposure comparable with duration of interpanetary spaceflight and recovered both biomolecules and cells complexes upon rehydration

Using δ15N of Chironomidae as an index of nitrogen sources and processing within watersheds as part of EPA's National Aquatic Resource Surveys

NASA Astrophysics Data System (ADS)

Brooks, J. R.; Compton, J.; Herlihy, A.; Sobota, D. J.; Stoddard, J.; Weber, M.

2014-12-01

Nitrogen (N) removal in watersheds is an important regulating ecosystem service that can help reduce N pollution in the nation's waterways. However, processes that remove N such as denitrification are generally determined at point locations. Measures that integrate N processing within watersheds and over time would be particularly useful for assessing the degree of this vital service. Because most N removal processes isotopically enrich the N remaining, δ15N from basal food-chain organisms in aquatic ecosystems can provide information on watershed N processing. As part of EPA's National Aquatic Resource Surveys (NARS), we measured δ15N of Chironomidae in lakes, rivers and streams because these larval aquatic insects were found in abundance in almost every lake and stream in the U.S. Using information on nitrogen loading to the watershed, and total N concentrations within the water, we assessed when elevated chironomid δ15N would indicate N removal rather than possible enriched sources of N. Chironomid δ15N values ranged from -4 to +20 ‰, and were higher in rivers and streams than in lakes (median = 7.6 ‰ vs. 4.8 ‰, respectively), indicating that N was processed to a greater degree in lotic chironomids than in lentic ones. For both, δ15N increased with watershed-level agricultural land cover and N loading, and decreased as precipitation increased. In rivers and streams with high synthetic N loading, we found lower N concentrations in streams with higher chironomid δ15N values, suggesting greater N removal. At low levels of synthetic N loading, the pattern reversed, and streams with enriched chironomid δ15N had higher N concentrations, suggesting enriched sources such as manure or sewage. Our results indicate that chironomid δ15N values can provide valuable information about watershed-level N inputs and processing for national water quality monitoring efforts.

Quantitative Temperature Reconstructions from Holocene and Late Glacial Lake Sediments in the Tropical Andes using Chironomidae (non-biting midges)

NASA Astrophysics Data System (ADS)

Matthews-Bird, F.; Gosling, W. D.; Brooks, S. J.; Montoya, E.; Coe, A. L.

2014-12-01

Chironomidae (non-biting midges) is a family of two-winged aquatic insects of the order Diptera. They are globally distributed and one of the most diverse families within aquatic ecosystems. The insects are stenotopic, and the rapid turnover of species and their ability to colonise quickly favourable habitats means chironomids are extremely sensitive to environmental change, notably temperature. Through the development of quantitative temperature inference models chironomids have become important palaeoecological tools. Proxies capable of generating independent estimates of past climate are crucial to disentangling climate signals and ecosystem response in the palaeoecological record. This project has developed the first modern environmental calibration data set in order to use chironomids from the Tropical Andes as quantitative climate proxies. Using surface sediments from c. 60 lakes from Bolivia, Peru and Ecuador we have developed an inference model capable of reconstructing temperatures, with a prediction error of 1-2°C, from fossil assemblages. Here we present the first Lateglacial and Holocene chironomid-inferred temperature reconstructions from two sites in the tropical Andes. The first record, from a high elevation (4153 m asl) lake in the Bolivian Andes, shows persistently cool temperatures for the past 15 kyr, punctuated by warm episodes in the early Holocene (9-10 kyr BP). The chironomid-inferred Holocene temperature trends from a lake sediment record on the eastern Andean flank of Ecuador (1248 m asl) spanning the last 5 millennia are synchronous with temperature changes in the NGRIP ice core record. The temperature estimates suggest along the eastern flank of the Andes, at lower latitudes (~1°S), climate closely resemble the well-established fluctuations of the Northern Hemisphere for this time period. Late-glacial climate fluctuations across South America are still disputed with some palaeoecological records suggesting evidence for Younger Dryas like events. Estimates from quantitative climate proxies such as chironomids will help constrain these patterns and further our understanding of climate teleconnections on Quaternary timescales.

Morphological identification and COI barcodes of adult flies help determine species identities of chironomid larvae (Diptera, Chironomidae).

PubMed

Failla, A J; Vasquez, A A; Hudson, P; Fujimoto, M; Ram, J L

2016-02-01

Establishing reliable methods for the identification of benthic chironomid communities is important due to their significant contribution to biomass, ecology and the aquatic food web. Immature larval specimens are more difficult to identify to species level by traditional morphological methods than their fully developed adult counterparts, and few keys are available to identify the larval species. In order to develop molecular criteria to identify species of chironomid larvae, larval and adult chironomids from Western Lake Erie were subjected to both molecular and morphological taxonomic analysis. Mitochondrial cytochrome c oxidase I (COI) barcode sequences of 33 adults that were identified to species level by morphological methods were grouped with COI sequences of 189 larvae in a neighbor-joining taxon-ID tree. Most of these larvae could be identified only to genus level by morphological taxonomy (only 22 of the 189 sequenced larvae could be identified to species level). The taxon-ID tree of larval sequences had 45 operational taxonomic units (OTUs, defined as clusters with >97% identity or individual sequences differing from nearest neighbors by >3%; supported by analysis of all larval pairwise differences), of which seven could be identified to species or 'species group' level by larval morphology. Reference sequences from the GenBank and BOLD databases assigned six larval OTUs with presumptive species level identifications and confirmed one previously assigned species level identification. Sequences from morphologically identified adults in the present study grouped with and further classified the identity of 13 larval OTUs. The use of morphological identification and subsequent DNA barcoding of adult chironomids proved to be beneficial in revealing possible species level identifications of larval specimens. Sequence data from this study also contribute to currently inadequate public databases relevant to the Great Lakes region, while the neighbor-joining analysis reported here describes the application and confirmation of a useful tool that can accelerate identification and bioassessment of chironomid communities.

Morphological identification and COI barcodes of adult flies help determine species identities of chironomid larvae (Diptera, Chironomidae)

USGS Publications Warehouse

Failla, Andrew Joseph; Vasquez, Adrian Amelio; Hudson, Patrick L.; Fujimoto, Masanori; Ram, Jeffrey L.

2016-01-01

Establishing reliable methods for the identification of benthic chironomid communities is important due to their significant contribution to biomass, ecology and the aquatic food web. Immature larval specimens are more difficult to identify to species level by traditional morphological methods than their fully developed adult counterparts, and few keys are available to identify the larval species. In order to develop molecular criteria to identify species of chironomid larvae, larval and adult chironomids from Western Lake Erie were subjected to both molecular and morphological taxonomic analysis. Mitochondrial cytochrome c oxidase I (COI) barcode sequences of 33 adults that were identified to species level by morphological methods were grouped with COI sequences of 189 larvae in a neighbor-joining taxon-ID tree. Most of these larvae could be identified only to genus level by morphological taxonomy (only 22 of the 189 sequenced larvae could be identified to species level). The taxon-ID tree of larval sequences had 45 operational taxonomic units (OTUs, defined as clusters with >97% identity or individual sequences differing from nearest neighbors by >3%; supported by analysis of all larval pairwise differences), of which seven could be identified to species or ‘species group’ level by larval morphology. Reference sequences from the GenBank and BOLD databases assigned six larval OTUs with presumptive species level identifications and confirmed one previously assigned species level identification. Sequences from morphologically identified adults in the present study grouped with and further classified the identity of 13 larval OTUs. The use of morphological identification and subsequent DNA barcoding of adult chironomids proved to be beneficial in revealing possible species level identifications of larval specimens. Sequence data from this study also contribute to currently inadequate public databases relevant to the Great Lakes region, while the neighbor-joining analysis reported here describes the application and confirmation of a useful tool that can accelerate identification and bioassesment of chironomid communities.

Reconstruction of past methane availability in an Arctic Alaska wetland indicates climate influenced methane release during the past ~12,000 years

USGS Publications Warehouse

Wooller, Matthew J.; Pohlman, John W.; Gaglioti, Benjamin V.; Langdon, Peter; Jones, Miriam; Anthony, Katey M. Walter; Becker, Kevin W.; Hinrichs, Kai-Uwe; Elvert, Marcus

2012-01-01

Atmospheric contributions of methane from Arctic wetlands during the Holocene are dynamic and linked to climate oscillations. However, long-term records linking climate variability to methane availability in Arctic wetlands are lacking. We present a multi-proxy ~12,000 year paleoecological reconstruction of intermittent methane availability from a radiocarbon-dated sediment core (LQ-West) taken from a shallow tundra lake (Qalluuraq Lake) in Arctic Alaska. Specifically, stable carbon isotopic values of photosynthetic biomarkers and methane are utilized to estimate the proportional contribution of methane-derived carbon to lake-sediment-preserved benthic (chironomids) and pelagic (cladocerans) components over the last ~12,000 years. These results were compared to temperature, hydrologic, and habitat reconstructions from the same site using chironomid assemblage data, oxygen isotopes of chironomid head capsules, and radiocarbon ages of plant macrofossils. Cladoceran ephippia from ~4,000 cal year BP sediments have δ13C values that range from ~−39 to −31‰, suggesting peak methane carbon assimilation at that time. These low δ13C values coincide with an apparent decrease in effective moisture and development of a wetland that included Sphagnum subsecundum. Incorporation of methane-derived carbon by chironomids and cladocerans decreased from ~2,500 to 1,500 cal year BP, coinciding with a temperature decrease. Live-collected chironomids with a radiocarbon age of 1,640 cal year BP, and fossil chironomids from 1,500 cal year BP in the core illustrate that ‘old’ carbon has also contributed to the development of the aquatic ecosystem since ~1,500 cal year BP. The relatively low δ13C values of aquatic invertebrates (as low as −40.5‰) provide evidence of methane incorporation by lake invertebrates, and suggest intermittent climate-linked methane release from the lake throughout the Holocene.

Effects of Lumbriculus variegatus (Annelida, Oligochaete) bioturbation on zinc sediment chemistry and toxicity to the epi-benthic invertebrate Chironomus tepperi (Diptera: Chironomidae).

PubMed

Colombo, Valentina; Pettigrove, Vincent J; Hoffmann, Ary A; Golding, Lisa A

2016-09-01

Classical laboratory-based single-species sediment bioassays do not account for modifications to toxicity from bioturbation by benthic organisms which may impact predictions of contaminated sediment risk to biota in the field. This study aims to determine the effects of bioturbation on the toxicity of zinc measured in a standard laboratory bioassay conducted with chironomid larvae (Chironomus tepperi). The epi-benthic chironomid larvae were exposed to two different levels of sediment contamination (1600 and 1980 mg/kg of dry weight zinc) in the presence or absence of annelid worms (Lumbriculus variegatus) which are known to be tolerant to metal and to have a large impact on sediment properties through bioturbation. Chironomids had 5-6x higher survival in the presence of L. variegatus which shows that bioturbation had a beneficial effect on the chironomid larvae. Chemical analyses showed that bioturbation induced a flux of zinc from the pore water into the water column, thereby reducing the bioavailability of zinc in pore water to the chironomid larvae. This also suggested that pore water was the major exposure path for the chironomids to metals in sediment. During the study, annelid worms (Oligochaetes) produced a thin layer of faecal pellets at the sediment surface, a process known to: (i) create additional adsorption sites for zinc, thus reducing its availability, (ii) increase the microbial abundance that in turn could represent an additional food source for opportunistic C. tepperi larvae, and (iii) modify the microbial community's structure and alter the biogeochemical processes it governs thus indirectly impact zinc toxicity. This study represents a contribution in recognising bioturbating organisms as "ecological engineers" as they directly and indirectly influence metal bioavailability and impact other sediment-inhabiting species. This is significant and should be considered in risk assessment of zinc levels (and other metals) in contaminated sediment when extrapolating from laboratory studies to the field. Copyright © 2016 Elsevier Ltd. All rights reserved.

Holocene temperature variations at a high-altitude site in the Eastern Alps: a chironomid record from Schwarzsee ob Sölden, Austria

PubMed Central

Ilyashuk, Elena A.; Koinig, Karin A.; Heiri, Oliver; Ilyashuk, Boris P.; Psenner, Roland

2011-01-01

Few well-dated, quantitative Holocene temperature reconstructions exist from high-altitude sites in the Central Eastern Alps. Here, we present a chironomid-based quantitative reconstruction of mean July air temperatures (TJuly) throughout the Holocene for a remote high-mountain lake, Schwarzsee ob Sölden, situated above the treeline at 2796 m a.s.l. in the Austrian Alps. Applying a chironomid-temperature inference model developed from lakes of the Alpine region to a high-resolution chironomid record from the lake provides evidence for early Holocene (ca 10000–8600 cal yr BP) TJuly of up to 8.5 °C, i.e. >4 °C above the modern (1977–2006) mean July temperature. The reconstruction reveals the so-called ‘8.2-ka cold event’ centered at ca 8250–8000 cal yr BP with temperatures ca 3 °C below the early-Holocene thermal maximum. Rather warm (ca 6 °C) and productive conditions prevailed during ca 7900–4500 cal yr BP. The chironomid record suggests a climate transition between ca 5200 and 4500 cal yr BP to cooler TJuly. A distinct cooling trend is evident from ca 4500 until ca 2500 cal yr BP. Thereafter, the study site experienced its coldest conditions (around 4 °C or less) throughout the rest of the Holocene, with the exception of the warming trend during the late 20th century. Beside other factors, the Northern Hemisphere summer insolation seems to be the major driving force for the long-term trends in TJuly at high altitudes in the Eastern Alps. Due to the extreme location of the lake and the limited temperature range represented by the applied calibration data set, the chironomid-based temperature reconstruction fails to track phases of the late-Holocene climatic history with TJuly cooler than 4 °C. Further chironomid-based palaeoclimate model and down-core studies are required to address this problem, provide more realistic TJuly estimates from undisturbed high-altitude lakes in the Alps, and extract a reliable regional temperature signal. PMID:21317974

Pupal development of Ceratitis capitata (Diptera: Tephritidae) and Diachasmimorpha longicaudata (Hymenoptera: Braconidae) at different moisture values in four soil types.

PubMed

Bento, F de M M; Marques, R N; Costa, M L Z; Walder, J M M; Silva, A P; Parra, J R P

2010-08-01

This study aimed to evaluate adult emergence and duration of the pupal stage of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and emergence of the fruit fly parasitoid, Diachasmimorpha longicaudata (Ashmead), under different moisture conditions in four soil types, using soil water matric potential. Pupal stage duration in C. capitata was influenced differently for males and females. In females, only soil type affected pupal stage duration, which was longer in a clay soil. In males, pupal stage duration was individually influenced by moisture and soil type, with a reduction in pupal stage duration in a heavy clay soil and in a sandy clay, with longer duration in the clay soil. As matric potential decreased, duration of the pupal stage of C. capitata males increased, regardless of soil type. C. capitata emergence was affected by moisture, regardless of soil type, and was higher in drier soils. The emergence of D. longicaudata adults was individually influenced by soil type and moisture factors, and the number of emerged D. longicaudata adults was three times higher in sandy loam and lower in a heavy clay soil. Always, the number of emerged adults was higher at higher moisture conditions. C. capitata and D. longicaudata pupal development was affected by moisture and soil type, which may facilitate pest sampling and allow release areas for the parasitoid to be defined under field conditions.

Effects of summer drawdown on the fishes and larval chironomids in Beulah Reservoir, Oregon

USGS Publications Warehouse

Rose, Brien P.; Mesa, Matthew G.

2013-01-01

Summer drawdown of Beulah Reservoir, Oregon, could adversely affect fish and invertebrate production, limit sport fishing opportunities, and hinder the recovery of threatened species. To assess the impacts of drawdown, we sampled fish and Chironomidae larvae in Beulah Reservoir in the springs of 2006 to 2008. The reservoir was reduced to 68% of full pool in 2006 and to run-of-river level in 2007. From spring 2006 to spring 2007, the catch per unit effort (CPUE) of fyke nets decreased significantly for dace [Rhinichthys spp.] and northern pikeminnow [Ptychocheilus oregonensis], increased significantly for suckers [Catastomus spp.] and white crappies [Pomoxis nigromaculatus], and was similar for redside shiners [Richardsonius balteatus]. CPUE of gillnets either increased significantly or remained similar depending on genera, and the size structure of redside shiners, suckers, and white crappies changed appreciably. From 2007 to 2008, the CPUE of northern pikeminnow, redside shiners, suckers, and white crappies decreased significantly depending on gear and the size structure of most fishes changed. Springtime densities of chironomid larvae in the water column were significantly higher in 2006 than in 2008, but other comparisons were similar. The densities of benthic chironomids were significantly lower in substrates that were frequently dewatered compared to areas that were partially or usually not dewatered. Individuals from frequently dewatered areas were significantly smaller than those from other areas and the densities of benthic chironomids in 2008 were significantly lower than other years. Summer drawdown can reduce the catch and alter the size structure of fishes and chironomid larvae in Beulah Reservoir.

An evaluation of benthic community measures using laboratory-derived sediment effect concentrations

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

Dwyer, F.J.; Canfield, T.J.; Ingersoll, C.G.

1995-12-31

Sediment effect concentrations (SECs) are contaminant sediment concentrations which are frequently associated with sediment toxicity. Recently, a number of different SECs have been calculated from laboratory toxicity tests with field collected sediments using Chironomus tentans, Chironomus riparius, and Hyalella azteca. Toxicity endpoints included (depending upon species) lethality, growth and sexual maturation. The authors selected the Effect Range Median (ERM) calculated for 28-d Hyalella azteca as an SEC for evaluating six different benthic community measures as indicators of contaminated sediment. The benthic measures included: taxa richness, chironomid genera richness, percent chironomid deformity, chironomid biotic index, ratio of chironomids/oligochaetes, and oligochaete bioticmore » index. Benthic measures were obtained for 31 stations from the Great Lakes and 13 stations from Milltown Reservoir and Clark Fork River, MT. Each benthic measure was ranked from 1 to 100 and individual ranks and various combinations of ranks were plotted against the ratio of chemical concentration at the site/ERM calculated for that chemical (similar to a toxic unit approach) and the sum of the ERM ratios (sum of toxic units). Preliminary analysis indicates that, in general, benthic measures varied widely in relatively uncontaminated stations, confounding any underlying relationship that may have existed. The absence of chironomids, in areas with suitable habitat, seems to be indicative of grossly contaminated stations, but not an endpoint useful for discriminating stations with contaminant concentrations closer to the SEC. The usefulness of benthic measures as diagnostic tools for contaminated sediments and potential ways to improve these measures will be discussed.« less

The response of chironomidae (Diptera) to a long-term exclusion of terrestrial organic matter

Treesearch

Sally A. Entrekin; J. Bruce Wallace; Susan L. Eggert

2007-01-01

We examined the effects of a seven-year detrital exclusion on chironomid assemblages in an Appalachian headwater stream. We hypothesized that litter exclusion would lead to a reduction in all chironomids at both the subfamily and generic levels because organic matter serves as both food and habitat in these headwater streams. Tanytarsini total abundance and biomass...

Developing a chironomid training set for western South America (South-Central Chile): potential for quantitative temperature reconstructions

NASA Astrophysics Data System (ADS)

Araneda, A.; Larocque-Tobler, I.; Torrejon, F.; Grosjean, M.; Jana-Pinninghoff, P.; Ortega, C.; Urrutia, R.

2012-12-01

Quantitative climate reconstructions of the last two millennia are a fundamental issue in order to compare the current trends in climate observed nowadays. At global scale most of the climate reconstructions have been developed for the Northern Hemisphere, while for the Southern Hemisphere quantitative reconstructions are very rare and very limited geographically. The recognition of such disparity has generated among other research initiatives the LOTRED-SA Long-Term climate Reconstruction and Dynamics of (southern) South America, a collaborative, high-resolution multi-proxy approach within the framework of the IGBP-PAGES program. In this context our work presents the results of a 50-lakes training set in Central-Southern Chile developed with the aim to generate a basis for quantitative chironomid-inferred temperature reconstructions for this part of the continent. Chironomids (Insecta: Diptera) are aquatic insects that develop a great proportion of their life cycle as larvae in aquatic ecosystems. Several studies, developed mainly in the Northern Hemisphere, have proven their usefulness in reconstructing past climate due to the larvae's relationship to temperature. The training set developed here includes lakes located between 34 and 48 S, covering a broad temperature (as latitudinal) gradient. The surface (0-1 cm) sediment of each lake was sampled and chironomids, organic matter and nutrient were analyzed. Water analyses included the measurement of 10 variables (AirT, WBT, WST, N-tot, P-tot, Fe, Na, pH among others). In order to identify the most important variables explaining the highest variance in the chironomid assemblages, ordinations analyses were performed. A preliminary DCA analysis indicated, according to the length of gradients smaller than 3 STD, that a linear model was more appropriate for further analysis. Hence a RDA analysis was applied to the environmental and species data, indicating that the most important variables to determine chironomid assemblages are water temperature (WST) and organic matter (OM). The statistical performances of the first model evaluated for WST were relatively weak (r2boot = 0.46, RMSEP=0.79) compared with other models. Nevertheless, the results indicate that temperature is still an important predictor of chironomid distribution and that by increasing the number of lakes in the environmental gradient will further increase the predictive performance and contribute to climate reconstruction in the region. Funding for this research is from Fondecyt project No. 11080158 and from de cooperation project CONICYT-SER-01 and CJRP 1001 between Switzerland and Chile. Partial funding of Fondecyt projects 1120765 and 1120807, is also acknowledged.

Influence of media type and moisture on adult development and pupal mortality in Rhagoletis indifferens (Diptera:Tephritidae)

USDA-ARS?s Scientific Manuscript database

Adult emergence and pupal mortality of tephritid flies depend on soil type and/or moisture. In this study, the influence of media type and moisture on adult development and pupal mortality in western cherry fruit fly, Rhagoletis indifferens Curran, was assessed. Inside sealed containers, a higher ...

Why on the snow? Winter emergence strategies of snow-active Chironomidae (Diptera) in Poland.

PubMed

Soszyńska-Maj, Agnieszka; Paasivirta, Lauri; Giłka, Wojciech

2016-10-01

A long-term study of adult non-biting midges (Chironomidae) active in winter on the snow in mountain areas and lowlands in Poland yielded 35 species. The lowland and mountain communities differed significantly in their specific composition. The mountain assemblage was found to be more diverse and abundant, with a substantial contribution from the subfamily Diamesinae, whereas Orthocladiinae predominated in the lowlands. Orthocladius wetterensis Brundin was the most characteristic and superdominant species in the winter-active chironomid communities in both areas. Only a few specimens and species of snow-active chironomids were recorded in late autumn and early winter. The abundance of chironomids peaked in late February in the mountain and lowland areas with an additional peak in the mountain areas in early April. However, this second peak of activity consisted mainly of Orthocladiinae, as Diamesinae emerged earliest in the season. Most snow-active species emerged in mid- and late winter, but their seasonal patterns differed between the 2 regions as a result of the different species composition and the duration of snow cover in these regions. Spearman's rank correlation coefficient tests yielded positive results between each season and the number of chironomid individuals recorded in the mountain area. A positive correlation between air temperature, rising to +3.5 °C, and the number of specimens recorded on the snow in the mountain community was statistically significant. The winter emergence and mate-searching strategies of chironomids are discussed in the light of global warming, and a brief compilation of most important published data on the phenomena studied is provided. © 2015 Institute of Zoology, Chinese Academy of Sciences.

Holocene coastal paleoenvironmental record, Bay of Brest

NASA Astrophysics Data System (ADS)

Fernane, Assia; Gandouin, Emmanuel; Goslin, Jérôme; Penaud, Aurélie; Van Vliet lanoë, Brigitte

2013-04-01

Coastal areas are sensitive environments regarding the risk of submersion and the impact on biodiversity induced by salinity changes. These areas thus provide good palaeocecological archives to monitor palaeo sea level changes and the associated adaptation of different biological communities. The north-western coast of France has poorly been investigated regarding its Holocene palaeoecological signatures (Morzadec-Kerfourn, 1974; Naughton et al., 2007). Chironomids have been recognized to be an efficient tool for palaeoclimate and palaeosalinity reconstructions in lakes (Brooks, 2006), and more recently in river floodplains (Gandouin et al, 2006). In this study, environmental changes related to both climate processes and human disturbances, were reconstructed over the last 5000 years, based on pollen and chironomid assemblages from two coastal cores retrieved at Pors Milin (Brittany, NW France). The sedimentary sequences consist of terrestrial peaty layers interdigited with marine clastic deposits. The study area is composed by a sandy beach, truncating the peat, limited by a high sandy bar, and a back marsh developed at + 4 m NGF. Pollen and chironomid results reveal that anthropogenic factors would mainly control environmental changes that occurred in this sector. The disappearance of many chironomid taxa (inhabitants of main river channel) and the dramatic fall in diversity may have been induced by the development of the Merovingian forest clearance at Pors Milin. Indeed, we suggest that the development of agriculture, the river embankment and the draining of wetlands may explain the chironomid habitat loss and the subsequent fall of biodiversity. This change in faunal assemblages occurred synchronously with a decrease in the "arborean / non arborean" pollen ratio reflecting the land opening of the watershed. Several nitrophilous and anthropogenic pollen taxa reinforce our hypothesis concerning the development of agricultural and livestock farming activities at that time.

Pupal and Adult Parameters as Potential Indicators of Cottonwood Leaf Beetle (Coleoptera: Chrysomelidae) Fecundity and Longevity

Treesearch

David R. Coyle; Joel D. McMillin; Elwood R. Hart

1999-01-01

Cottonwood leaf beetle, Chrysomela scripta, pupae from a laboratory colony were weighed and monitored through adult emergence, oviposition, and mortality to determine if correlations existed between various pupal or adult parameters and fecundity or longevity. Forty-three female cottonwood leaf beetles were monitored. Pupal weight was not a good...

Proteomic identification of a potential sex biomarker for 2 fruit fly species at pupal stage

USDA-ARS?s Scientific Manuscript database

We collected brown and white pupae from rearing DTWP larvae on liquid diet and TSL strain from CDFA rearing facility respectively and daily and analyzed protein expression from pupal age 1-10 days old using 2D electrophoresis. In this report, two pupal color sexing strain [dorsalis translocation whi...

The potential association between menta deformities and trace elements in Chironomidae (Diptera) taken from a heavy metal contaminated river.

PubMed

Martinez, E A; Moore, B C; Schaumloffel, J; Dasgupta, N

2002-04-01

Elevated morphological deformity rates in Chironomidae larvae have been attributed to such pollutants as oil tars, pesticides, organochlorines, and heavy metals. The potential of chironomids as biological indicators of heavy metal contamination and bioavailability in a contaminated ecosystem was assessed. Chironomid larvae and river sediment were collected from the Coeur d' Alene River system, Idaho, USA, contaminated with heavy metals from mining activities. Chironomid larvae collected at contaminated sites exhibited mouthpart deformity proportions between 3.8 and 10.3% compared to the control site of 0.9%. As, Cd, Cu, Ni, Pb, and Zn were determined in both larvae and sediment samples. Significant correlation between metal concentrations and deformity rates were observed for all metals except Ni. The data also suggests that feeding habits may influence differences in pollution tolerance among genera.

Chironomids as indicators of natural and human impacts in a 700-yr record from the northern Patagonian Andes

NASA Astrophysics Data System (ADS)

Williams, Natalia; Rieradevall, Maria; Añón Suárez, Diego; Rizzo, Andrea; Daga, Romina; Ribeiro Guevara, Sergio; Arribére, María Angélica

2016-09-01

Chironomid communities were studied in a sediment core collected from Lake Moreno Oeste, located in Nahuel Huapi National Park. A major change in midge assemblages occurred at ∼AD 1760, which was characterized by a decrease of "cold taxa" including Polypedilum sp.2 and Dicrotendipes, and an increase of "warm taxa" including Apsectrotanypus and Polypedilum sp.1. These taxa are likely related to climatic conditions concurrent with the end of a cold period at ∼AD 1500-1700 and the beginning of a drying climate at ∼AD 1740-1900 in northern Patagonia. Coarse tephra layers had low midge diversity; however they did not disrupt the climatic trend as the community recovered rapidly after the event. Since AD 1910, after the increase in suburban housing, fish introduction, and the construction of a road, there was an increase in the relative abundances of taxa typically associated with the littoral zone, such as Parapsectrocladius, Riethia, Apsectrotanypus, and some Tanytarsini morphotypes. The main change in the chironomid community appears to be associated with long-term climate change. At the beginning of the 20th century, other site-specific environmental factors (catchment change and fish introduction) altered the chironomid assemblages, making it more difficult to understand the relative importance of each driver of assemblage change.

A chironomid-based reconstruction of summer temperatures in NW Iceland since AD 1650

NASA Astrophysics Data System (ADS)

Langdon, P. G.; Caseldine, C. J.; Croudace, I. W.; Jarvis, S.; Wastegård, S.; Crowford, T. C.

2011-05-01

Few studies currently exist that aim to validate a proxy chironomid-temperature reconstruction with instrumental temperature measurements. We used a reconstruction from a chironomid percentage abundance data set to produce quantitative summer temperature estimates since AD 1650 for NW Iceland through a transfer function approach, and validated the record against instrumental temperature measurements from Stykkishólmur in western Iceland. The core was dated through Pb-210, Cs-137 and tephra analyses (Hekla 1693) which produced a well-constrained dating model across the whole study period. Little catchment disturbance, as shown through geochemical (Itrax) and loss-on-ignition data, throughout the period further reinforce the premise that the chironomids were responding to temperature and not other catchment or within-lake variables. Particularly cold phases were identified between AD 1683-1710, AD 1765-1780 and AD 1890-1917, with relative drops in summer temperatures in the order of 1.5-2°C. The timing of these cold phases agree well with other evidence of cooler temperatures, notably increased extent of Little Ice Age (LIA) glaciers. Our evidence suggests that the magnitude of summer temperature cooling (1.5-2°C) was enough to force LIA Icelandic glaciers into their maximum Holocene extent, which is in accordance with previous modelling experiments for an Icelandic ice cap (Langjökull).

Spinosad: a biorational mosquito larvicide for use in car tires in southern Mexico

PubMed Central

2012-01-01

Background Car tires are important habitats for mosquito development because of the high density populations they can harbor and their presence in urban settings. Water in experimental tires was treated with one of three insecticides or an untreated control. Aquatic invertebrates were sampled at weekly intervals. Eggs, larval and pupal samples were laboratory-reared to estimate seasonal fluctuations in Aedes aegypti and Ae. albopictus abundance. Results Spinosad treatments at 1 or 5 ppm (mg a.i./liter) provided 6–8 weeks of effective control of Ae. aegypti, Ae. albopictus, Culex quinquefasiatus and Cx. coronator larvae, both in the dry season and the rainy season when mosquito populations increased markedly in southern Mexico. Spinosad continued to provide partial control of larvae for several weeks after initial recolonization of treated tires. The larvicidal performance of VectoBac 12AS (Bacillus thuringiensis var. israelensis) was relatively poor with one week of complete control of Aedes spp. larvae and no discernible control of Culex spp., whereas the duration of larvicidal activity of 1% temephos mineral-based granules was intermediate between those of VectoBac and spinosad treatments. Populations of chironomids, ostracods and Toxorhynchites theobaldi were generally reduced in spinosad and temephos treatments, but were similar in control and VectoBac treatments. Conclusion The present study is the first to report spinosad as an effective larvicide against Cx. coronator, which is currently invading the southern United States. These results substantiate the use of spinosad as a highly effective mosquito larvicide, even in habitats such as unused car tires that can represent prolific sources of adult mosquitoes. PMID:22608138

Paleolimnological assessment of the effects of lake acidification on Chironomidae (Diptera) assemblages in the Adirondack region of New York

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

Uutala, A.J.

1987-01-01

The stratigraphies of larval chironomid and Chaoborus (Diptera: Chironomidae and Chaoboridae) remains were determined for cores from five Adirondack lakes. Big Moose Lake, Deep Lake, Brook trout Lake and Upper Wallface Pond are currently acidic, while Windfall Pond is near neutral. Altered chironomid assemblages were evident in the four acidic lakes, and acid deposition was the most likely cause for the inferred changes. Declining pH was indicated beginning after 1950 in Big Moose L., after 1930 in Deep L. and Upper Wallface P., and after 1920 in Brook trout L. No recent pH change was inferred for Windfall P. Shiftsmore » in the chironomid assemblages were concordant with indications of declining pH inferred from analyses of cladocera, chrysophyte and diatom remains. The best indicators among the chironomid taxa were Heterotrissocladius changi, Micropsectra and Zavreliina, which tended to decline, and Salutschia cf. briani, Psectrocladius (Psectrocladius) and Tanytarsus, which tended to increase in abundance in response to increased acidity. Long-term presence of Chaoborus americanus in Deep L. and Upper Wallface P. indicated that fishes were probably never abundant in these lakes. Increases in the accumulation rates of C. americanus remains in Deep L. and Upper Wallface P. reflected the poor success and eventual halt of fish stocking in these lakes.« less

Use of chironomids (Diptera: Chironomidae) as bioindicators of contaminant stress: Biochemical, chromosomal and developmental measures

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

Ciborowski, J.J.H.; Cervi, L.; Sinasac, D.

1995-12-31

Sublethal environmental stresses produce effects ranging from subtle biochemical changes that protect an organism from damage, through developmental effects that interfere with growth and compromise fitness. Benthic chironomids live in intimate contact with the sediments to which most persistent chemicals are bound. Their short life cycle and unique developmental and genetic structure make them excellent candidates as biological indicators of stress. The authors evaluated the short and long-term responses of Chironomus riparius larvae to contaminants. To determine short-term stress responses, third and fourth instar Chironomus larvae were exposed to up to 1.5 {micro}L/g creosote or up to 100 {micro}g/g Cdmore » for 12 h. Creosote-exposed larvae exhibited proteins of a molecular weight consistent with production of heat shock proteins of the HSP 70 family. Exposure to Cd induced significant enlargement of Balbiani Rings of the 4th chromosome in chironomid salivary glands, indicative of increased transcription of RNA precursors to salivary mucoproteins. Chironomus larvae individually reared from second instar larvae at [Cd] up to 40 {micro}g/g sediment exhibited increased incidence of mentum deformities, and delayed development that resulted in larger size at pupation. Thus deformities are biologically relevant indicators of stress. Overall, the results confirm the potential of chironomids as relevant bioindicators of contaminant stress.« less

Spatial variation in incidence of mouthpart deformities in larval chironomids (Diptera) from western Lake Erie

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

Hudson, L.A.; Ciborowski, J.J.H.; Corkum, L.D.

1995-12-31

The major source of contaminants to the sediments of the western basin of Lake Erie is the Detroit River. In order to determine if contaminant levels are reflected in incidences of genotoxicity of benthic invertebrates, the authors examined larvae of chironomids for mouthpart (mentum) deformities. Sediment genotoxicity is indicated when incidence of deformities in susceptible genera exceeds 5%. Samples were collected from three locations along the contaminant gradient extending from the Detroit River along the main shipping channel of the western basin. A composite sample was taken from several central locations in the western basin. Chironomids were hand-picked from ponarmore » grab or box core samples. The heads were mounted, identified to genus and examined for mentum deformities (extra or missing teeth). Chironomus dominated all samples. The incidence of deformities ({+-}SE) in Chironomus was greatest in the Trenton Channel of the Detroit River (7.8 {+-} 2.2%, n = 153), declined to 5.2 {+-} 1.4% (n = 233) in the center of the basin and was the lowest off East Sister Island (1.9 {+-} 0.9%, n = 210). The incidence of deformities was 4.4 {+-} 0.8% (n = 610) at a reference site on the Canadian side of the Detroit River (Crystal Bay). The spatial pattern of chironomid mentum deformities suggests that sediment genotoxicity declines from west to east in western Lake Erie.« less

Is routine dengue vector surveillance in central Brazil able to accurately monitor the Aedes aegypti population? Results from a pupal productivity survey.

PubMed

Pilger, Daniel; Lenhart, Audrey; Manrique-Saide, Pablo; Siqueira, Joao Bosco; da Rocha, Welington Tristão; Kroeger, Axel

2011-09-01

To assess how well the Aedes aegypti infestation rapid survey, Levantamento Rapido de Indice para Aedes aegypti (LIRAa), is able to accurately estimate dengue vector densities and target the most important breeding sites in Goiania, Brazil. In February 2009, a pupal productivity survey was conducted in 2 districts of the city of Goiania, central Brazil. The results were compared to those of LIRAas conducted in the same districts during the months before and after the pupal productivity survey. In the pupal productivity survey, 2,024 houses were surveyed and 2,969 water-holding containers were inspected. Discarded small water containers most frequently contained immature Ae. aegypti. The most pupal-productive containers were elevated water tanks, roof gutters and water holding roofs. Combined, these three containers accounted for <40% of all positive containers but produced >70% of all pupae. In the two districts where the pupal productivity survey was conducted, the house indices were 5.1 and 4.6 and the Breteau indices were 5.9 and 6.0. In contrast, the two LIRAs conducted in the same two districts resulted in an average house index of 1.5 and Breteau index of 2.5, with discarded items identified as the most frequently infested container type. Both the LIRAa and the pupal productivity survey identified discarded items as being most frequently infested with immature stages of Ae. aegypti, but the pupal productivity survey showed that elevated containers produced the greatest proportion of Ae. aegypti pupae (a proxy measure of adult vector density) and that the values of the Stegomyia indices were substantially underestimated by LIRAa. Although both surveys differ considerably in terms of sampling method and manpower, in the case of this study the LIRAa did not accurately identify or target the containers that were the most important to adult mosquito production. © 2011 Blackwell Publishing Ltd.

Sexual dimorphism of bed bug (Cimex lectularis) attraction and aggregation responses to cuticular extracts from nymph exuviae

USDA-ARS?s Scientific Manuscript database

A large variety of releaser pheromones are used by insects to attract or disperse conspecifics, while group cohesion is often influenced by primer pheromones that induce behavioral or physiological changes. Differentiating the roles of such pheromones in insect taxa displaying intermediate levels of...

Total and methyl mercury contents and distribution characteristics in cicada, Cryptotympana atrata (Fabricius).

PubMed

Zheng, Dongmei; Zhang, Zhongsheng; Wang, Qichao

2010-06-01

Total and methyl mercury concentrations of cicada bodies, wings, and exuviae were investigated to study the mercury distribution characteristics. Results indicated that total and methyl mercury concentrations of cicada bodies were 2.64 mg/kg and 123.93 ng/g on average, respectively. In cicada tissues, total mercury concentrations were found to increase in the order of exuviae (0.50 mg/kg on average) < wings (0.98 mg/kg on average) < cicada bodies (2.64 mg/kg on average) and methyl mercury concentrations of cicada bodies were 123.93 ng/g on average and were the highest. Methyl mercury concentrations accounted for about 4.69% of total mercury in cicada bodies and most mercury was in inorganic forms in cicada. Sex differences of total mercury concentrations were significantly great (F = 8.433, p < 0.01) and total mercury concentrations of the males, which were 3.38 mg/kg on average, were much higher. Correlation analysis showed that neither total nor methyl mercury concentrations of cicada bodies was significantly related to the corresponding contents of soil (r = 0.0598, p > 0.05).

Determination of fluoxetine in Dermestes maculatus (Coleoptera: Dermestidae) by a spectrophotometric method.

PubMed

Zanetti, Noelia I; Ferrero, Adriana A; Centeno, Néstor D

2016-12-01

The aims of this study were to detect and quantify fluoxetine, an antidepressant, from entomological samples. Larvae, pupae and adults of Dermestes maculatus (Coleoptera, Dermestidae) were reared on pig muscle previously treated with fluoxetine. The concentration selected, 2000mg/kg, emulates a fluoxetine overdose lethal to humans and laboratory animals. Thirty larvae on the fourth and fifth stages, 50 adults and several exuviae were analyzed for fluoxetine content. Detection of fluoxetine was performed by UV spectrophotometry at 270 and 277nm. All developmental stages of D. maculatus and exuviae were positive for fluoxetine. We also quantified the drug and no significant differences were found either between the days or the stages in the general model, but at 277nm a tendency of the concentration to decrease with time was observed. Concentrations of fluoxetine at 277nm were almost equal or greater than those at 270nm. This is the first study to detect and quantify fluoxetine from entomological samples and, in particular, from D. maculatus beetles. Copyright © 2016 The Chartered Society of Forensic Sciences. Published by Elsevier Ireland Ltd. All rights reserved.

Non-linear feeding functional responses in the Greater Flamingo (Phoenicopterus roseus) predict immediate negative impact of wetland degradation on this flagship species

PubMed Central

Deville, Anne-Sophie; Grémillet, David; Gauthier-Clerc, Michel; Guillemain, Matthieu; Von Houwald, Friederike; Gardelli, Bruno; Béchet, Arnaud

2013-01-01

Accurate knowledge of the functional response of predators to prey density is essential for understanding food web dynamics, to parameterize mechanistic models of animal responses to environmental change, and for designing appropriate conservation measures. Greater flamingos (Phoenicopterus roseus), a flagship species of Mediterranean wetlands, primarily feed on Artemias (Artemia spp.) in commercial salt pans, an industry which may collapse for economic reasons. Flamingos also feed on alternative prey such as Chironomid larvae (e.g., Chironomid spp.) and rice seeds (Oryza sativa). However, the profitability of these food items for flamingos remains unknown. We determined the functional responses of flamingos feeding on Artemias, Chironomids, or rice. Experiments were conducted on 11 captive flamingos. For each food item, we offered different ranges of food densities, up to 13 times natural abundance. Video footage allowed estimating intake rates. Contrary to theoretical predictions for filter feeders, intake rates did not increase linearly with increasing food density (type I). Intake rates rather increased asymptotically with increasing food density (type II) or followed a sigmoid shape (type III). Hence, flamingos were not able to ingest food in direct proportion to their abundance, possibly because of unique bill structure resulting in limited filtering capabilities. Overall, flamingos foraged more efficiently on Artemias. When feeding on Chironomids, birds had lower instantaneous rates of food discovery and required more time to extract food from the sediment and ingest it, than when filtering Artemias from the water column. However, feeding on rice was energetically more profitable for flamingos than feeding on Artemias or Chironomids, explaining their attraction for rice fields. Crucially, we found that food densities required for flamingos to reach asymptotic intake rates are rarely met under natural conditions. This allows us to predict an immediate negative effect of any decrease in prey density upon flamingo foraging performance. PMID:23762525

Transcriptome Characterization Analysis of Bactrocera minax and New Insights into Its Pupal Diapause Development with Gene Expression Analysis

PubMed Central

Dong, Yongcheng; Desneux, Nicolas; Lei, Chaoliang; Niu, Changying

2014-01-01

Bactrocera minax is a major citrus pest distributed in China, Bhutan and India. The long pupal diapause duration of this fly is a major bottleneck for artificial rearing and underlying mechanisms remain unknown. Genetic information on B. minax transcriptome and gene expression profiles are needed to understand its pupal diapause. High-throughput RNA-seq technology was used to characterize the B. minax transcriptome and to identify differentially expressed genes during pupal diapause development. A total number of 52,519,948 reads were generated and assembled into 47,217 unigenes. 26,843 unigenes matched to proteins in the NCBI database using the BLAST search. Four digital gene expression (DGE) libraries were constructed for pupae at early diapause, late diapause, post-diapause and diapause terminated developmental status. 4,355 unigenes showing the differences expressed across four libraries revealed major shifts in cellular functions of cell proliferation, protein processing and export, metabolism and stress response in pupal diapause. When diapause was terminated by 20-hydroxyecdysone (20E), many genes involved in ribosome and metabolism were differentially expressed which may mediate diapause transition. The gene sets involved in protein and energy metabolisms varied throughout early-, late- and post-diapause. A total of 15 genes were selected to verify the DGE results through quantitative real-time PCR (qRT-PCR); qRT-PCR expression levels strongly correlated with the DGE data. The results provided the extensive sequence resources available for B. minax and increased our knowledge on its pupal diapause development and they shed new light on the possible mechanisms involved in pupal diapause in this species. PMID:25285037

Live Cell Imaging of Butterfly Pupal and Larval Wings In Vivo

PubMed Central

Ohno, Yoshikazu; Otaki, Joji M.

2015-01-01

Butterfly wing color patterns are determined during the late larval and early pupal stages. Characterization of wing epithelial cells at these stages is thus critical to understand how wing structures, including color patterns, are determined. Previously, we successfully recorded real-time in vivo images of developing butterfly wings over time at the tissue level. In this study, we employed similar in vivo fluorescent imaging techniques to visualize developing wing epithelial cells in the late larval and early pupal stages 1 hour post-pupation. Both larval and pupal epithelial cells were rich in mitochondria and intracellular networks of endoplasmic reticulum, suggesting high metabolic activities, likely in preparation for cellular division, polyploidization, and differentiation. Larval epithelial cells in the wing imaginal disk were relatively large horizontally and tightly packed, whereas pupal epithelial cells were smaller and relatively loosely packed. Furthermore, larval cells were flat, whereas pupal cells were vertically elongated as deep as 130 μm. In pupal cells, many endosome-like or autophagosome-like structures were present in the cellular periphery down to approximately 10 μm in depth, and extensive epidermal feet or filopodia-like processes were observed a few micrometers deep from the cellular surface. Cells were clustered or bundled from approximately 50 μm in depth to deeper levels. From 60 μm to 80 μm in depth, horizontal connections between these clusters were observed. The prospective eyespot and marginal focus areas were resistant to fluorescent dyes, likely because of their non-flat cone-like structures with a relatively thick cuticle. These in vivo images provide important information with which to understand processes of epithelial cell differentiation and color pattern determination in butterfly wings. PMID:26107809

Live Cell Imaging of Butterfly Pupal and Larval Wings In Vivo.

PubMed

Ohno, Yoshikazu; Otaki, Joji M

2015-01-01

Butterfly wing color patterns are determined during the late larval and early pupal stages. Characterization of wing epithelial cells at these stages is thus critical to understand how wing structures, including color patterns, are determined. Previously, we successfully recorded real-time in vivo images of developing butterfly wings over time at the tissue level. In this study, we employed similar in vivo fluorescent imaging techniques to visualize developing wing epithelial cells in the late larval and early pupal stages 1 hour post-pupation. Both larval and pupal epithelial cells were rich in mitochondria and intracellular networks of endoplasmic reticulum, suggesting high metabolic activities, likely in preparation for cellular division, polyploidization, and differentiation. Larval epithelial cells in the wing imaginal disk were relatively large horizontally and tightly packed, whereas pupal epithelial cells were smaller and relatively loosely packed. Furthermore, larval cells were flat, whereas pupal cells were vertically elongated as deep as 130 μm. In pupal cells, many endosome-like or autophagosome-like structures were present in the cellular periphery down to approximately 10 μm in depth, and extensive epidermal feet or filopodia-like processes were observed a few micrometers deep from the cellular surface. Cells were clustered or bundled from approximately 50 μm in depth to deeper levels. From 60 μm to 80 μm in depth, horizontal connections between these clusters were observed. The prospective eyespot and marginal focus areas were resistant to fluorescent dyes, likely because of their non-flat cone-like structures with a relatively thick cuticle. These in vivo images provide important information with which to understand processes of epithelial cell differentiation and color pattern determination in butterfly wings.

A pupal transcriptomic screen identifies Ral as a target of store-operated calcium entry in Drosophila neurons.

PubMed

Richhariya, Shlesha; Jayakumar, Siddharth; Abruzzi, Katharine; Rosbash, Michael; Hasan, Gaiti

2017-02-14

Transcriptional regulation by Store-operated Calcium Entry (SOCE) is well studied in non-excitable cells. However, the role of SOCE has been poorly documented in neuronal cells with more complicated calcium dynamics. Previous reports demonstrated a requirement for SOCE in neurons that regulate Drosophila flight bouts. We refine this requirement temporally to the early pupal stage and use RNA-sequencing to identify SOCE mediated gene expression changes in the developing Drosophila pupal nervous system. Down regulation of dStim, the endoplasmic reticular calcium sensor and a principal component of SOCE in the nervous system, altered the expression of 131 genes including Ral, a small GTPase. Disruption of Ral function in neurons impaired flight, whereas ectopic expression of Ral in SOCE-compromised neurons restored flight. Through live imaging of calcium transients from cultured pupal neurons, we confirmed that Ral does not participate in SOCE, but acts downstream of it. These results identify neuronal SOCE as a mechanism that regulates expression of specific genes during development of the pupal nervous system and emphasizes the relevance of SOCE-regulated gene expression to flight circuit maturation.

A chironomid-based record of temperature variability during the past 4000 years in northern China and its possible societal implications

NASA Astrophysics Data System (ADS)

Wang, Haipeng; Chen, Jianhui; Zhang, Shengda; Zhang, David D.; Wang, Zongli; Xu, Qinghai; Chen, Shengqian; Wang, Shijin; Kang, Shichang; Chen, Fahu

2018-03-01

Long-term, high-resolution temperature records which combine an unambiguous proxy and precise dating are rare in China. In addition, the societal implications of past temperature change on a regional scale have not been sufficiently assessed. Here, based on the modern relationship between chironomids and temperature, we use fossil chironomid assemblages in a precisely dated sediment core from Gonghai Lake to explore temperature variability during the past 4000 years in northern China. Subsequently, we address the possible regional societal implications of temperature change through a statistical analysis of the occurrence of wars. Our results show the following. (1) The mean annual temperature (TANN) was relatively high during 4000-2700 cal yr BP, decreased gradually during 2700-1270 cal yr BP and then fluctuated during the last 1270 years. (2) A cold event in the Period of Disunity, the Sui-Tang Warm Period (STWP), the Medieval Warm Period (MWP) and the Little Ice Age (LIA) can all be recognized in the paleotemperature record, as well as in many other temperature reconstructions in China. This suggests that our chironomid-inferred temperature record for the Gonghai Lake region is representative. (3) Local wars in Shanxi Province, documented in the historical literature during the past 2700 years, are statistically significantly correlated with changes in temperature, and the relationship is a good example of the potential societal implications of temperature change on a regional scale.

Bluegill growth as modified by plant density: an exploration of underlying mechanisms

USGS Publications Warehouse

Savino, Jacqueline F.; Marschall, Elizabeth A.; Stein, Roy A.

1992-01-01

Bluegill (Lepomis macrochira) growth varies inconsistently with plant density. In laboratory and field experiments, we explored mechanisms underlying bluegill growth as a function of plant and invertebrate density. In the laboratory, bluegills captured more chironomids (Chironomus riparius) than damselflies (Enallagma spp. and Ischnura spp.), but energy intake per time spent searching did not differ between damselfly and chironomid treatments. From laboratory data, we described prey encounter rates as functions of plant and invertebrate density. In Clark Lake, Ohio, we created 0.05-ha mesocosms of inshore vegetation to generate macrophyte densities of 125, 270, and 385 stems/m2 of Potamogeton and Ceratophyllum and added 46-mm bluegill (1/m2). In these mesocosms, invertebrate density increased as a function of macrophyte density. Combining this function with encounter rate functions derived from laboratory data, we predicted that bluegill growth should peak at a high macrophyte density, greater than 1000 stems/m2, even though growth should change only slightly beyond 100 stems/m2. Consistent with our predictions, bluegills did not grow differentially, nor did their use of different prey taxa differ, across macrophyte densities in the field. Bluegills preferred chironomid pupae, which were relatively few in numbers but vulnerable to predation, whereas more cryptic, chironomid larvae, which were associated with vegetation but were relatively abundant, were eaten as encountered. Bluegill avoided physid snails. Contrary to previous work, vegetation did not influence growth or diet of bluegill beyond relatively low densities owing to the interaction between capture probabilities and macroinvertebrate densities.

Modulation of cyclic CO(2) release in response to endogenous changes of metabolism during pupal development of Zophobas rugipes (Coleoptera: Tenebrionidae).

PubMed

Kaiser, Alexander; Hartzendorf, Sandra; Wobschall, Annabell; Hetz, Stefan K

2010-05-01

Understanding the mechanisms of gas exchange regulation in insects currently is a hot topic of insect physiology. Endogenous variation of metabolism during pupal development offers a great opportunity to study the regulation of respiratory patterns in insects. Here we show that metabolic rates during pupal development of the tenebrionid beetle Zophobas rugipes reveal a typical U-shaped curve and that, with the exception of 9-day-old pupae, the time between two bursts of CO(2) (interburst phase) was the only parameter of cyclic CO(2) gas exchange patterns that was adjusted to changing metabolic rates. The volume of CO(2) released in a burst was kept constant, suggesting a regulation for accumulation and release of a fixed amount of CO(2) throughout pupal development. We detected a variety of discontinuous and cyclic gas exchange patterns, which were not correlated with any periods of pupal development, suggesting a high among individual variability. An occasional occurrence of continuous CO(2) release patterns at low metabolic rates was very likely caused by single defective non-occluding spiracles. Copyright 2009 Elsevier Ltd. All rights reserved.

Rectal sac distention is induced by 20-hydroxyecdysone in the pupa of Bombyx mori.

PubMed

Suzuki, Takumi; Sakurai, Sho; Iwami, Masafumi

2009-03-01

Holometabolous insects do not excrete but store metabolic wastes during the pupal period. The waste is called meconium and is purged after adult emergence. Although the contents of meconium are well-studied, the developmental and physiological regulation of meconium accumulation is poorly understood. In Bombyx mori, meconium is accumulated in the rectal sac; thereby, the rectal sac distends at the late pupal stage. Here, we show that rectal sac distention occurs between 4 and 5 days after pupation. The distention is halted by brain-removal just after larval-pupal ecdysis but not by brain-removal 1 day after pupation. In the pupae, brain-removal just after ecdysis kept the hemolymph ecdysteroid titer low during early and mid-pupal stages. An injection of 20-hydroxyecdysone (20E) evoked the distention that was halted by brain-removal in a dose-dependent manner. Therefore, brain-removal caused the lack of ecdysteroid, and rectal sac distention did not appear in the brain-removed pupae because of the lack of ecdysteroid. We conclude that rectal sac distention is one of the developmental events regulated by 20E during the pupal period in B. mori.

Differential necrophoric behaviour of the ant Solenopsis invicta towards fungal-infected corpses of workers and pupae.

PubMed

Qiu, H-L; Lu, L-H; Shi, Q-X; Tu, C-C; Lin, T; He, Y-R

2015-10-01

Necrophoric behaviour is critical sanitation behaviour in social insects. However, little is known about the necrophoric responses of workers towards different developmental stages in a colony as well as its underlying mechanism. Here, we show that Solenopsis invicta workers display distinct necrophoric responses to corpses of workers and pupae. Corpses of workers killed by freezing (dead for <1 h) were carried to a refuse pile, but pupal corpses would take at least 1 day to elicit workers' necrophoric response. Metarhizium anisopliae-infected pupal corpses accelerated the necrophoric behaviour of resident workers, with 47.5% of unaffected corpses and 73.8% infected corpses discarded by 1 day post-treatment). We found that fungus-infected pupal corpses had a higher concentration of fatty acids (palmitic acid, oleic acid and linoleic acid) on their surface. We experimentally confirmed that linoleic and oleic acids would elicit a necrophoric response in workers. The appearance of linoleic and oleic acids appeared to be chemical signals involved in recognition of pupal corpses, and M. anisopliae infection could promote the accumulation of fatty acids on surface of pupal corpses resulting in accelerated necrophoric responses of workers.

A pupal transcriptomic screen identifies Ral as a target of store-operated calcium entry in Drosophila neurons

PubMed Central

Richhariya, Shlesha; Jayakumar, Siddharth; Abruzzi, Katharine; Rosbash, Michael; Hasan, Gaiti

2017-01-01

Transcriptional regulation by Store-operated Calcium Entry (SOCE) is well studied in non-excitable cells. However, the role of SOCE has been poorly documented in neuronal cells with more complicated calcium dynamics. Previous reports demonstrated a requirement for SOCE in neurons that regulate Drosophila flight bouts. We refine this requirement temporally to the early pupal stage and use RNA-sequencing to identify SOCE mediated gene expression changes in the developing Drosophila pupal nervous system. Down regulation of dStim, the endoplasmic reticular calcium sensor and a principal component of SOCE in the nervous system, altered the expression of 131 genes including Ral, a small GTPase. Disruption of Ral function in neurons impaired flight, whereas ectopic expression of Ral in SOCE-compromised neurons restored flight. Through live imaging of calcium transients from cultured pupal neurons, we confirmed that Ral does not participate in SOCE, but acts downstream of it. These results identify neuronal SOCE as a mechanism that regulates expression of specific genes during development of the pupal nervous system and emphasizes the relevance of SOCE-regulated gene expression to flight circuit maturation. PMID:28195208

Holocene Climate, Fire and Vegetation Change Inferred from Lacustrine Proxies in the Tropical Andes, Laguna Yanacocha, SE Peru

NASA Astrophysics Data System (ADS)

Axford, Y.; Isaacson, M.; Matthews-Bird, F.; Schellinger, G. C.; Carrio, C. L.; Kelly, M. A.; Lowell, T. V.; Beal, S. A., Jr.; Stroup, J. S.; Tapia, P. M.

2016-12-01

We present a 12,000-year long paleoenvironmental reconstruction from a small high-elevation lake in southeastern Peru. Climate and environmental change are inferred from chironomid species assemblages, charcoal abundance, size and morphology, and the abundance of some important pollen and spore types (Poaceae, Asteraceae, Isoetes). We employ a new chironomid training set developed for tropical South America (Matthews-Bird et al. 2016) to interpret shifts in chironomid assemblages. The sedimentary record from Yanacocha was first discussed by Beal et al. (2014), who reconstructed Hg deposition and measured metals, biogenic silica and loss-on-ignition through the Holocene. Additional downcore proxies are presented by Stroup et al. (this meeting). Yanacocha sits at 4910 m asl and less than 2 km from Quelccaya Ice Cap (QIC), but the lake's watershed has been topographically isolated from glacier meltwater since 12.3 ka. We compare our inferences from biological proxies with independent constraints on paleoclimate derived from published reconstructions of QIC fluctuations. Previous studies found that temperature was the primary driver of late Holocene fluctuations of QIC (e.g., Stroup et al. 2014), but records from the broader region indicate the Holocene also saw major changes in hydroclimate. Most modern precipitation at Yanacocha derives from the Amazon Basin to the east, and El Niño years are associated with drier conditions. Holocene sediments at Yanacocha likely thus record both changes in temperature and hydroclimate. Vegetation was sparse and no charcoal was preserved prior to 11.7 ka, whereas the early Holocene saw the highest overall pollen concentrations of the entire record and the onset of charcoal preservation. An increase in charcoal abundance, decrease in pollen concentrations, and shifts in vegetation and chironomid assemblages at Yanacocha suggest drier conditions from 9 to 3.5 ka, consistent with widespread regional evidence for early to middle Holocene aridity. One sample at 8.4 ka contains uniquely abundant charcoal, Poaceae and Asteraceae, possibly recording a brief (<500 yr) and uniquely dramatic dry event at that time. Shifts in chironomid assemblages, including a major shift centered on 1000 AD, indicate a variable climate through the late Holocene.

Assessing The Effects of Within-lake Variability of Fossil Assemblages On Quantitative Chironomid-inferred Temperature Reconstruction

NASA Astrophysics Data System (ADS)

Heiri, O.; Birks, H. J. B.; Brooks, S. J.; Velle, G.; Willassen, E.

An important aspect when applying organism-based palaeolimnological methods to sediment cores is the inherent variability of fossil assemblages within a lake basin. Subfossil chironomids in lake sediments have been used extensively to quantify past summer air and water temperatures. However, little is known on how heterogeneous fossil distribution affects these estimates. In an effort to assess this variability we took a total of 20 surface sediment samples each in three small and shallow (7-9 m wa- ter depth) Norwegian lakes. In every lake two transects of seven samples were taken from the centre of the lake towards the littoral and six samples in the deepest part of the lake basin. Although the fossil assemblages were generally very similar within a lake basin, there was - in all three lakes - a distinct shift in the abundances of chi- ronomid taxa towards the littoral (water depth explaining 10-18% of the total variance in the percentage data as assessed by a Detrended Canonical Correspondence Anal- ysis). When we applied to our data a quantitative chironomid-July air temperature transfer-function based on surface sediments from the deepest parts of 153 Norwegian lakes, the variability of reconstructed temperatures in our three study lakes was only slightly smaller in the 6 deep-water samples (standard deviations (SD) of 0.48, 0.52 and 0.58C) than in all the 20 samples (SD of 0.55, 0.56 and 0.59 C). Our results suggest that within-lake variability of subfossil chironomid assemblages can account for a significant part of the overall prediction error of the chironomid-July air tempera- ture model of 1.03C. Furthermore, the lack of a clear trend in inferred values towards the littoral and the similar standard deviation of the total samples as compared to the deep-water samples suggest that the Norwegian transfer-function, though calibrated on samples from the deepest part of the lake, may also be applicable to sediment cores from closer to the lake shore. It remains to be tested, however, if this holds true in deeper lakes than the ones sampled in our study.

Fossil Chironomidae (Insecta: Diptera) as Paleothermometers in the African Tropics

NASA Astrophysics Data System (ADS)

Eggermont, H.; Heiri, O.; Russell, J.; Vuille, M.; Audenaert, L.; Klaassen, G.; Verschuren, D.

2008-12-01

Reconstruction of Africa's temperature history from natural climate archives such as lake sediments is essential to amend the current scarcity of information on natural tropical climate and ecosystem variability. Chironomids are well-established paleothermometers in north-temperate/boreal regions, but their potential in tropical lakes has never before been assessed. We surveyed sub-fossil chironomid assemblages in surface sediments from 65 lakes and permanent pools in southwestern Uganda and central/southern Kenya, spanning elevations between 489 and 4575 m asl. Using various subsets of lakes and corresponding Surface-Water Temperatures (SWTemp) and Mean Annual Air Temperatures (MATemp), we developed a series of inference models for quantitative paleotemperature reconstruction. Models using both low-, mid- and high-elevation sites suffer to some extent from the small number of samples between 2500 and 3500 m asl, and from the presence of ecologically distinct but morphologically indistinguishable taxa. Models confined to mountain sites produce poorer error statistics, but are less prone to the biogeographical and taxonomic complexities associated with long climatic gradients. Overall, error statistics compare favourably with those of inference models developed for temperate regions, indicating that fossil assemblages of African Chironomidae can be valuable indicators of past temperature change. We subsequently used these models to evaluate whether high-elevation lakes in the Rwenzori Mountains (>3000 m asl) have been impacted by climate warming in recent centuries by comparing temperatures inferred from chironomid assemblages in modern sediments with those derived from chironomid assemblages in sediments deposited within or briefly after the Little Ice Age (1270-1850 AD). Depending on the model used, between 44 and 63% of the 16 lakes studied indicate significantly warmer temperatures in recent times (corresponding with an average MATemp rise of 0.88 ° C, and average SWTemp rise of 1.33 ° C), while all but one of the other lakes show temperature changes that are statistically insignificant. We conclude that chironomid communities in Rwenzori lakes adequately record past temperature changes, with potential for evaluating the impacts of past air temperature variation on the long-term dynamics of the Rwenzori glaciers.

The Tribolium chitin synthase genes TcCHS1 and TcCHS2 are specialized for synthesis of epidermal cuticle and midgut peritrophic matrix.

PubMed

Arakane, Y; Muthukrishnan, S; Kramer, K J; Specht, C A; Tomoyasu, Y; Lorenzen, M D; Kanost, M; Beeman, R W

2005-10-01

Functional analysis of the two chitin synthase genes, TcCHS1 and TcCHS2, in the red flour beetle, Tribolium castaneum, revealed unique and complementary roles for each gene. TcCHS1-specific RNA interference (RNAi) disrupted all three types of moult (larval-larval, larval-pupal and pupal-adult) and greatly reduced whole-body chitin content. Exon-specific RNAi showed that splice variant 8a of TcCHS1 was required for both the larval-pupal and pupal-adult moults, whereas splice variant 8b was required only for the latter. TcCHS2-specific RNAi had no effect on metamorphosis or on total body chitin content. However, RNAi-mediated down-regulation of TcCHS2, but not TcCHS1, led to cessation of feeding, a dramatic shrinkage in larval size and reduced chitin content in the midgut.

Pupal habitat productivity of Anopheles gambiae complex mosquitoes in a rural village in western Kenya.

PubMed

Mutuku, Francis M; Bayoh, M Nabie; Gimnig, John E; Vulule, John M; Kamau, Luna; Walker, Edward D; Kabiru, Ephantus; Hawley, William A

2006-01-01

The productivity of larval habitats of the malaria vector Anopheles gambiae for pupae (the stage preceding adult metamorphosis) is poorly known, yet adult emergence from habitats is the primary determinant of vector density. To assess it, we used absolute sampling methods in four studies involving daily sampling for 25 days in 6 habitat types in a village in western Kenya. Anopheles gambiae s.s. comprised 82.5% of emergent adults and Anopheles arabiensis the remainder. Pupal production occurred from a subset of habitats, primarily soil burrow pits, and was discontinuous in time, even when larvae occupied all habitats continuously. Habitat stability was positively associated with pupal productivity. In a dry season, pupal productivity was distributed between burrow pits and pools in streambeds. Overall, these data support the notion that source reduction measures against recognizably productive habitats would be a useful component of an integrated management program for An. gambiae in villages.

Stylet biogenesis in Bactericera cockerelli (Hemiptera: Triozidae).

PubMed

Cicero, Joseph M

2017-07-01

The discovery of 'Ca. Liberibacter solanacearum', causal agent of certain solanaceous and apiaceous crop diseases, inside the functional (intrastadial) and pharate stylet anatomy of the potato psyllid prompted elucidation of the mechanism of stylet replacement as a novel exit portal in the transmission pathway. In Hemiptera, presumptive (formative) stylets, secreted during consecutive pharate instars, replace functional stylets lost with the exuviae. In potato psyllids, each functional stylet has a hollow core filled with a cytology that extends out of the core to form a hemispherical aggregate of cells, the 'end-cap', somewhat resembling a golf ball on a tee. A tightly folded mass of extremely thin cells, the 'matrix', occurs inside the end-cap. Micrograph interpretations indicate that during the pharate stage, the end-cap apolyses from the core and 'deconstructs' to release and expand the matrix into a long, coiled tube, the 'atrium'. Cells that were in contact with the inner walls of the functional stylet core maintain their position at the apex of the tube, and secrete a new stylet, apex first, the growing length of which descends into the tube until completed. They then despool from the coils into their functional position as the exuviae is shed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Segmentally distributed metamorphic changes in neural circuits controlling abdominal bending in the hawk moth Manduca sexta.

PubMed

Lemon, W C; Levine, R B

1997-06-01

During the metamorphosis of Manduca sexta the larval nervous system is reorganized to allow the generation of behaviors that are specific to the pupal and adult stages. In some instances, metamorphic changes in neurons that persist from the larval stage are segment-specific and lead to expression of segment-specific behavior in later stages. At the larval-pupal transition, the larval abdominal bending behavior, which is distributed throughout the abdomen, changes to the pupal gin trap behavior which is restricted to three abdominal segments. This study suggests that the neural circuit that underlies larval bending undergoes segment specific modifications to produce the segmentally restricted gin trap behavior. We show, however, that non-gin trap segments go through a developmental change similar to that seen in gin trap segments. Pupal-specific motor patterns are produced by stimulation of sensory neurons in abdominal segments that do not have gin traps and cannot produce the gin trap behavior. In particular, sensory stimulation in non-gin trap pupal segments evokes a motor response that is faster than the larval response and that displays the triphasic contralateral-ipsilateral-contralateral activity pattern that is typical of the pupal gin trap behavior. Despite the alteration of reflex activity in all segments, developmental changes in sensory neuron morphology are restricted to those segments that form gin traps. In non-gin trap segments, persistent sensory neurons do not expand their terminal arbors, as do sensory neurons in gin trap segments, yet are capable of eliciting gin trap-like motor responses.

Observations of cocooned Hydrobaenus (Diptera: Chironomidae) larvae in Lake Michigan

USGS Publications Warehouse

Tucker, Taaja R.; Hudson, Patrick L.; Riley, Stephen

2016-01-01

Larvae of the family Chironomidae have developed a variety of ways to tolerate environmental stress, including the formation of cocoons, which allows larvae to avoid unfavorable temperature conditions, drought, or competition with other chironomids. Summer cocoon formation by younger instars of the genus Hydrobaenus Fries allows persistence through increased temperatures and/or intermittent dry periods in arid regions or temporary habitats, but this behavior was not observed in the Great Lakes until the current study. Cocoon-aestivating Hydrobaenus sp. larvae were found in benthic grab samples collected in 2010–2013 near Sleeping Bear Dunes National Lakeshore in northern Lake Michigan with densities up to 7329/m2. The aestivating species was identified as Hydrobaenus johannseni (Sublette, 1967), and the associated chironomid community was typical for an oligotrophic nearshore system. Hydrobaenus cocoon formation in the Great Lakes was likely previously unnoticed due to the discrepancies between the genus' life history and typical benthos sampling procedures which has consequences for describing chironomid communities where Hydrobaenus is present.

Survival in extreme environment by "preserve-expand-specialize" strategy: lessons from comparative genomics of an anhydrobiotic midge.

NASA Astrophysics Data System (ADS)

Gusev, Oleg; Sugimoto, Manabu; Novikova, Nataliya; Sychev, Vladimir; Okuda, Takashi; Kikawada, Takahiro

2012-07-01

Anhydrobiotic chironomid larvae of Polypedilum vanderplanki (Diptera) can withstand prolonged complete desiccation as well as other external stresses including ionizing radiation. Recent experiments showed that this insect is able to survive long-tern exposure to real outer space. At the same time, we found that dehydration causes alterations in chromatin structure and a severe fragmentation of nuclear DNA in the cells of the larvae despite successful anhydrobiosis. Analysis of several remote populations of the chironomid in Africa that desiccation-related DNA damage might be a driving genetic force for rapid radiation within the species. First results of ongoing genome project suggest that origin and evolution of anhydrobiosis in this single insect species related to rapid duplication of the genes, coding late embryogenesis abundant proteins (LEA) and other molecular agents directly involved in desiccation resistance in the cells. Analysis of genome-wide mRNA expression profiles in the larvae subjected to desiccation shows that joint-activity of large multiple-genes coding regions in the genome involved in control of anhydrobiosis-related molecular adaptations in the chironomid.

A DNA Barcode Library for Korean Chironomidae (Insecta: Diptera) and Indexes for Defining Barcode Gap

PubMed Central

Kim, Sungmin; Song, Kyo-Hong; Ree, Han-Il; Kim, Won

2012-01-01

Non-biting midges (Diptera: Chironomidae) are a diverse population that commonly causes respiratory allergies in humans. Chironomid larvae can be used to indicate freshwater pollution, but accurate identification on the basis of morphological characteristics is difficult. In this study, we constructed a mitochondrial cytochrome c oxidase subunit I (COI)-based DNA barcode library for Korean chironomids. This library consists of 211 specimens from 49 species, including adults and unidentified larvae. The interspecies and intraspecies COI sequence variations were analyzed. Sophisticated indexes were developed in order to properly evaluate indistinct barcode gaps that are created by insufficient sampling on both the interspecies and intraspecies levels and by variable mutation rates across taxa. In a variety of insect datasets, these indexes were useful for re-evaluating large barcode datasets and for defining COI barcode gaps. The COI-based DNA barcode library will provide a rapid and reliable tool for the molecular identification of Korean chironomid species. Furthermore, this reverse-taxonomic approach will be improved by the continuous addition of other speceis’ sequences to the library. PMID:22138764

Abridged pupa identification key to the common container-breeding mosquitoes in urban Southeast Asia.

PubMed

Bangs, Michael J; Focks, Dana A

2006-09-01

Pupal surveys have been advocated as an alternative or surrogate surveillance method for estimating densities of adult Aedes aegypti and Aedes albopictus. Usually, this survey strategy has required that collected pupae eclose to adults before attempting species identification. Using the pupal survey method in Yogyakarta, Indonesia, this rearing step was obviated with the pupal morphological key described herein for identifying preserved or live pupae. Examination of pupae for the identification of various container-inhabiting mosquito genera and target aedine species proved to be accurate and far less time-consuming and problematic than rearing pupae to adults.

Application of a frequency distribution method for determining instars of the beet armyworm (Lepidoptera: Noctuidae) from widths of cast head capsules

Treesearch

Y. Chen; S. J. Seybold

2013-01-01

Instar determination of field-collected insect larvae has generally been based on the analysis of head capsule width frequency distributions or bivariate plotting, but few studies have tested the validity of such methods. We used head capsules from exuviae of known instars of the beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae),...

Urban heat island effect on cicada densities in metropolitan Seoul.

PubMed

Nguyen, Hoa Q; Andersen, Desiree K; Kim, Yuseob; Jang, Yikweon

2018-01-01

Urban heat island (UHI) effect, the ubiquitous consequence of urbanization, is considered to play a major role in population expansion of numerous insects. Cryptotympana atrata and Hyalessa fuscata are the most abundant cicada species in the Korean Peninsula, where their population densities are higher in urban than in rural areas. We predicted a positive relationship between the UHI intensities and population densities of these two cicada species in metropolitan Seoul. To test this prediction, enumeration surveys of cicada exuviae densities were conducted in 36 localities located within and in the vicinity of metropolitan Seoul. Samples were collected in two consecutive periods from July to August 2015. The abundance of each species was estimated by two resource-weighted densities, one based on the total geographic area, and the other on the total number of trees. Multiple linear regression analyses were performed to identify factors critical for the prevalence of cicada species in the urban habitat. C. atrata and H. fuscata were major constituents of cicada species composition collected across all localities. Minimum temperature and sampling period were significant factors contributing to the variation in densities of both species, whereas other environmental factors related to urbanization were not significant. More cicada exuviae were collected in the second rather than in the first samplings, which matched the phenological pattern of cicadas in metropolitan Seoul. Cicada population densities increased measurably with the increase in temperature. Age of residential complex also exhibited a significantly positive correlation to H. fuscata densities, but not to C. atrata densities. Effects of temperature on cicada densities have been discerned from other environmental factors, as cicada densities increased measurably in tandem with elevated temperature. Several mechanisms may contribute to the abundance of cicadas in urban environments, such as higher fecundity of females, lower mortality rate of instars, decline in host plant quality, and local adaptation of organisms, but none of them were tested in the current study. In sum, results of the enumeration surveys of cicada exuviae support the hypothesis that the UHI effect underlies the population expansion of cicadas in metropolitan Seoul. Nevertheless, the underlying mechanisms for this remain untested.

An improved temporal formulation of pupal transpiration in Glossina.

PubMed

Childs, S J

2015-04-01

The temporal aspect of a model of pupal dehydration is improved upon. The observed dependence of pupal transpiration on time is attributed to an alternation between two, essential modes, for which the deposition of a thin, pupal skin inside the puparium and its subsequent demise are thought to be responsible. For each mode of transpiration, the results of the Bursell investigation into pupal dehydration are used as a rudimentary data set. These data are generalised to all temperatures and humidities by invoking the property of multiplicative separability. The problem, then, is that as the temperature varies with time, so does the metabolism and the developmental stages to which the model data pertain, must necessarily warp. The puparial-duration formula of Phelps and Burrows and Hargrove is exploited to facilitate a mapping between the constant-temperature time domain of the data and that of some, more general case at hand. The resulting, Glossina morsitans model is extrapolated to other species using their relative surface areas, their relative protected and unprotected transpiration rates and their different fourth instar excretions (drawing, to a lesser extent, from the data of Buxton and Lewis). In this way the problem of pupal dehydration is formulated as a series of integrals and the consequent survival can be predicted. The discovery of a distinct definition for hygrophilic species, within the formulation, prompts the investigation of the hypothetical effect of a two-day heat wave on pupae. This leads to the conclusion that the classification of species as hygrophilic, mesophilic and xerophilic is largely true only in so much as their third and fourth instars are and, possibly, the hours shortly before eclosion. Copyright © 2015 Elsevier Inc. All rights reserved.

Reconstruction of Holocene palaeoclimate and environment in the Khatanga region, Russian Arctic

NASA Astrophysics Data System (ADS)

Syrykh, Ludmila; Nazarova, Larisa

2016-04-01

Arctic regions are highly sensitive to changes in temperature and precipitation, and their Late Quaternary environmental history is very important for understanding of present and past climate trends. Though the timing of Holocene climate change is well established for wide parts of the Northern Hemisphere, suitable palaeoenvironmental records are still scarce in the Russian Siberian Arctic. Taimyr Peninsula (74oN, 100oE) is the northernmost part of Russia. Thus, this area is probably one of the most promising regions for the reconstruction of the Late Quaternary environment in dependence on changes in global and regional climate and the atmospheric circulation. (Andreev et al., 2004).The area is characterized by a continental climate with long, severe winters, and short summers. The modern temperatures are about 10-14oC in July, and - 32 to 34oC in January. Annual precipitation ranges from about 300-400 mm at low elevations to about 600-800 mm on the western slopes of the Putorana Plateau (Atlas Arktiki, 1985). The frost-free period is ca. 35 days. Almost all the territory is underlain by continues permafrost. Periglacial landscape is dominated by tundra and taiga vegetation. Aquatic organisms such as chironomids (Insecta: Diptera) are recognized as the best biological indicators for quantifying past changes in air temperature or lake chemistry (Letter et al., 1997; Brooks and Birks, 2000; Battarbee, 2000; Massaferro and Brooks, 2002; Solovieva et al., 2005). Chironomids belong to the most abundant group of fresh-water bottom-dwelling macroinvertebrates. Because of their short life cycle, chironomids quickly adapt to environmental changes and in global scale the distribution and abundance of chironomids are mostly limited by temperature (Walker and Mathewes, 1987; Warwick, 1989; Hann et al., 1992; Walker et al., 1992). Larval head capsules of chironomids preserved in lake sediment as subfossils are abundant, identifiable and serve as indicators of the environmental conditions in Quarternary Period and especially in Holocene (Smol et al., 2005; Nazarova et al., 2013). Main aim of our the research is to perform a high-resolution Holocene temperature reconstructions for Taymyr (the northern most region of Russian Arctic) using lake sediments from Chatanga region, and statistical chironomid-based inference models for estimation of mean July air temperature and water depth from lakes in north-eastern Russia. We performed a multy-proxy reconstruction of palaeoclimate and environment in the Holocene using a 132 cm sediment core covering 6 ka of sedimentation. Based of the chironomids analysis we performed a quantitative reconstruction of mean July air temperature in the Chatanga region (Taymyr Peninsula). Our investigation has shown that modern fauna is well represented along the whole sediment core. Dominating taxa along the core are cold stenotherms such as Chironomus anthracinus-type, Hydrobaenus lugubris-type and Tanytarsus lugens-type. Faunistic composition of lower part of the core (before 5 ka BP) is characteristic for a warmer conditions, which is in accordance with the earlier studies showing that mean summer temperatures may have been 2.5° to 5.0°C warmer than today in Taymyr peninsula between 9 and 4 ka BP. During the last 3500 years, our record suggests cooler conditions as elsewhere in the Russian arctic. This project was financed by DAAD "Mikhail Lomonosov Program"

The Vertical Dynamics of Larval Chironomids on Artificial Substrates in Lake Lido (Bogor, Indonesia)

PubMed Central

Wardiatno, Yusli; Krisanti, Majariana

2013-01-01

The composition and abundance of chironomid larval communities was studied on artificial substrates in Lido Lake, located in Bogor, West Java, Indonesia. The lake is organically enriched as a result of fish farming activity. Seventy two artificial substrates were deployed at three depths (2.0, 3.5 and 5.0 m) at two sites: a cage culture site and a non-cage culture site (control). Larval chironomid larvae were collected 7, 14, 28 and 56 days after the artificial substrates were deployed. In addition, selected physical and chemical parameters of the water were simultaneously measured. Three chironomid subfamilies, the Chironominae, Tanypodinae and Orthocladiinae, were found at both sites. At the cage culture site, both diversity and total abundance were significantly higher at the 2.0 and 3.5 m depths than at the 5.0 m depth, but this was not the case at the non-cage culture site. Based on pooling of the data from all depths, a Mann-Whitney U test showed that the non-cage culture site had a significantly higher diversity and total abundance than the cage culture site. Dissolved oxygen (DO) and turbidity showed significant differences between the 2.0 m depth and the 2 greater depths at the cage culture site, whereas none of the environmental parameters showed significant differences among the three depths at the non-cage culture site. A comparison of the environmental parameters at the same depth at the two sites showed significant differences in turbidity, pH and DO. A Spearman rank correlation analysis at the cage culture site showed that abundance and DO were positively correlated, whereas abundance and turbidity were negatively correlated. However, only pH was negatively correlated with abundance at the non-cage culture site. PMID:24575246

Examination of the genetic basis for sexual dimorphism in the Aedes aegypti (dengue vector mosquito) pupal brain

PubMed Central

2014-01-01

Background Most animal species exhibit sexually dimorphic behaviors, many of which are linked to reproduction. A number of these behaviors, including blood feeding in female mosquitoes, contribute to the global spread of vector-borne illnesses. However, knowledge concerning the genetic basis of sexually dimorphic traits is limited in any organism, including mosquitoes, especially with respect to differences in the developing nervous system. Methods Custom microarrays were used to examine global differences in female vs. male gene expression in the developing pupal head of the dengue vector mosquito, Aedes aegypti. The spatial expression patterns of a subset of differentially expressed transcripts were examined in the developing female vs. male pupal brain through in situ hybridization experiments. Small interfering RNA (siRNA)-mediated knockdown studies were used to assess the putative role of Doublesex, a terminal component of the sex determination pathway, in the regulation of sex-specific gene expression observed in the developing pupal brain. Results Transcripts (2,527), many of which were linked to proteolysis, the proteasome, metabolism, catabolic, and biosynthetic processes, ion transport, cell growth, and proliferation, were found to be differentially expressed in A. aegypti female vs. male pupal heads. Analysis of the spatial expression patterns for a subset of dimorphically expressed genes in the pupal brain validated the data set and also facilitated the identification of brain regions with dimorphic gene expression. In many cases, dimorphic gene expression localized to the optic lobe. Sex-specific differences in gene expression were also detected in the antennal lobe and mushroom body. siRNA-mediated gene targeting experiments demonstrated that Doublesex, a transcription factor with consensus binding sites located adjacent to many dimorphically expressed transcripts that function in neural development, is required for regulation of sex-specific gene expression in the developing A. aegypti brain. Conclusions These studies revealed sex-specific gene expression profiles in the developing A. aegypti pupal head and identified Doublesex as a key regulator of sexually dimorphic gene expression during mosquito neural development. PMID:25729562

Pupal development and pigmentation process of a polka-dotted fruit fly, Drosophila guttifera (Insecta, Diptera).

PubMed

Fukutomi, Yuichi; Matsumoto, Keiji; Agata, Kiyokazu; Funayama, Noriko; Koshikawa, Shigeyuki

2017-06-01

Various organisms have color patterns on their body surfaces, and these color patterns are thought to contribute to physiological regulation, communication with conspecifics, and signaling with the environment. An adult fly of Drosophila guttifera (Insecta: Diptera: Drosophilidae) has melanin pigmentation patterns on its body and wings. Though D. guttifera has been used for research into color pattern formation, how its pupal development proceeds and when the pigmentation starts have not been well studied. In this study, we defined the pupal stages of D. guttifera and measured the pigment content of wing spots from the pupal period to the period after eclosion. Using a transgenic line which carries eGFP connected with an enhancer of yellow, a gene necessary for melanin synthesis, we analyzed the timing at which the yellow enhancer starts to drive eGFP. We also analyzed the distribution of Yellow-producing cells, as indicated by the expression of eGFP during pupal and young adult periods. The results suggested that Yellow-producing cells were removed from wings within 3 h after eclosion, and wing pigmentation continued without epithelial cells. Furthermore, the results of vein cutting experiments showed that the transport of melanin precursors through veins was necessary for wing pigmentation. These results showed the importance of melanin precursors transported through veins and of extracellular factors which were secreted from epithelial cells and left in the cuticle.

Density-dependent effects of omnivorous stream crayfish on benthic trophic dynamics

USGS Publications Warehouse

Ludlam, J.P.; Banks, B. T.; Magoulick, Daniel D.

2015-01-01

Crayfish are abundant and important consumers in aquatic food webs and crayfish invasions have demonstrated strong effects of crayfish on multiple trophic levels. Density may be an important factor determining the role of omnivorous crayfish in benthic communities, especially if density alters the strength of trophic interactions. The effect of crayfish density on a simple benthic food web using ceramic tiles was examined in three treatments (crayfish exclusion cage, cage control (open to crayfish), and exposed ceramic tiles) in mesocosms stocked with 6, 12, or 18 crayfish·m-2. We hypothesized that at low densities crayfish consumption of herbivorous chironomids would increase algal abundance, but at high densities crayfish would reduce both periphyton and invertebrates. In the experiment, periphyton and chironomid abundance increased with declining crayfish biomass on day 30 but not day 15. The magnitude of crayfish effects on day 15 periphyton chlorophyll a abundance increased with crayfish biomass, but crayfish effects on day 30 periphyton chlorophyll a or chironomid biomass did not increase with crayfish biomass. In this experiment there was little evidence for a trophic cascade at low crayfish densities and strong omnivory by crayfish dominated trophic dynamics.

Reconstructing temperatures from lake sediments in northern Europe: what do the biological proxies really tell us?

NASA Astrophysics Data System (ADS)

Cunningham, Laura; Holmes, Naomi; Bigler, Christian; Dadal, Anna; Bergman, Jonas; Eriksson, Lars; Brooks, Stephen; Langdon, Pete; Caseldine, Chris

2010-05-01

Over the past two decades considerable effort has been devoted to quantitatively reconstructing temperatures from biological proxies preserved in lake sediments, via transfer functions. Such transfer functions typically consist of modern sediment samples, collected over a broad environmental gradient. Correlations between the biological communities and environmental parameters observed over these broad gradients are assumed to be equally valid temporally. The predictive ability of such spatially based transfer functions has traditionally been assessed by comparisons of measured and inferred temperatures within the calibration sets, with little validation against historical data. Although statistical techniques such as bootstrapping may improve error estimation, this approach remains partly a circular argument. This raises the question of how reliable such reconstructions are for inferring past changes in temperature? In order to address this question, we used transfer functions to reconstruct July temperatures from diatoms and chironomids from several locations across northern Europe. The transfer functions used showed good internal calibration statistics (r2 = 0.66 - 0.91). The diatom and chironomid inferred July air temperatures were compared to local observational records. As the sediment records were non-annual, all data were first smoothed using a 15 yr moving average filter. None of the five biologically-inferred temperature records were correlated with the local meteorological records. Furthermore, diatom inferred temperatures did not agree with chironomid inferred temperatures from the same cores from the same sites. In an attempt to understand this poor performance the biological proxy data was compressed using principal component analysis (PCA), and the PCA axes compared to the local meteorological data. These analyses clearly demonstrated that July temperatures were not correlated with the biological data at these locations. Some correlations were observed between the biological proxies and autumn and spring temperatures, although this varied slightly between sites and proxies. For example, chironomid data from Iceland was most strongly correlated with temperatures in February, March and April whilst in northern Sweden, the chironomid data was most strongly correlated with temperatures in March, April and May. It is suggested that the biological data at these sites may be responding to changes in the length of the ice-free period or hydrological regimes (including snow melt), rather than temperature per se. Our findings demonstrate the need to validate inferred temperatures against local meteorological data. Where such validation cannot be undertaken, inferred temperature reconstructions should be treated cautiously.

A liquid larval diet for rearing Bactrocera invadens and Ceratitis fasciventris (Diptera:Tephritidae)

USDA-ARS?s Scientific Manuscript database

Bactrocera invadens Drew, Tsuruta & White and Ceratitis fasciventris (Bezzi) are the major fruit fly pests of fruits and vegetables in Africa. The effects of two types of larval diet, liquid and solid (carrot based), on various quality control parameters (pupal recovery, pupal weight, adult emergenc...

Metabolic profiling and biological capacity of Pieris brassicae fed with kale (Brassica oleracea L. var. acephala).

PubMed

Ferreres, Federico; Fernandes, Fátima; Oliveira, Jorge M A; Valentão, Patrícia; Pereira, José A; Andrade, Paula B

2009-06-01

Phenolic and organic acid profiles of aqueous extracts from Pieris brassicae material and the host kale (Brassica oleracea L. var. acephala) leaves were determined by HPLC/UV-DAD/MS(n)-ESI and HPLC-UV, respectively. The identified phenolics included acylated and nonacylated flavonoid glycosides, hydroxycinnamic acyl gentiobiosides, and sulphate phenolics. Kale exhibited the highest content (11g/kg lyophilized extract), while no phenolics were identified in the butterflies or exuviae. Nine different organic acids were characterized in the materials, with kale showing the highest amount (112g/kg lyophilized extract). With the exception of the exuviae extract, the rest were screened for bioactivity. Using spectrophotometric microassays, all exhibited antiradical capacity against DPPH and NO in a concentration-dependent way, whereas only kale and excrement extracts were active against superoxide. All displayed activity on intestinal smooth muscle, albeit with distinct relaxation-contraction profiles. Larvae and butterfly extracts were more efficacious for intestinal relaxation than was kale extract, whereas excrement extract evoked only contractions, thus evidencing their different compositions. Collectively, these results show that P. brassicae sequesters and metabolizes kale's phenolic compounds. Moreover, the extract's bioactivities suggest that they may constitute an interesting source of bioactive compounds whose complex chemical structures preclude either synthesis or isolation.

Mud and silk in the dark: A new type of millipede moulting chamber and first observations on the maturation moult in the order Callipodida.

PubMed

Reboleira, Ana Sofia P S; Enghoff, Henrik

2016-05-01

The postembryonic development of millipedes includes a series of stadia separated by moults, a process known as anamorphosis. The moulting process and especially the moulting into maturity, i.e., with fully developed copulatory organs, remains unknown for most millipede species. We have kept specimens of Lusitanipus alternans (Verhoeff, 1893) in the laboratory for one year and studied its moulting process, including the first study of the maturation moult in the order Callipodida. Unlike the typical silk cocoon reported for other callipodidans, this species builds a new type of solid moulting chamber, using the available substrate reinforced by a silken web. We present the detailed ultrastructure of the moulting chamber and silk. It takes five days to build the moulting chamber and between 29 (female) and 35 (male) days to shed the exuviae. The male maturation moult is preceded by an evagination of a gonopodal sac between the 6th and 7th body rings, in which the gonopods are developed. Females evaginated completely their vulval sacs, retracting them after shedding the exuviae. Vulval sac size seems to increase with the progressive reduction of the second pair of legs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of pupal parasitoids as biological control agents of filth flies on equine facilities

USDA-ARS?s Scientific Manuscript database

House flies, Musca domestica L., and stable flies, Stomoxys calcitrans (L.), (Diptera: Muscidae), are common pests on horse farms. The use of pupal parasitoids as biological control agents for filth flies is becoming more popular on equine facilities; however, there is a lack of information on the e...

Low temperature stress during pupal development and its effects on adult performance in alfalfa leafcutting bees

USDA-ARS?s Scientific Manuscript database

Megachile rotundata develop in brood cells constructed in cavities by adult females. Pre-pupal bees diapause over winter and resume development as temperatures (Ta) increase in spring. While many insects are tolerant of suboptimal Ta in their overwintering stages, insects that initiate active develo...

Simplified pupal surveys of Aedes aegypti (L.) for entomologic surveillance and dengue control.

PubMed

Barrera, Roberto

2009-07-01

Pupal surveys of Aedes aegypti (L.) are useful indicators of risk for dengue transmission, although sample sizes for reliable estimations can be large. This study explores two methods for making pupal surveys more practical yet reliable and used data from 10 pupal surveys conducted in Puerto Rico during 2004-2008. The number of pupae per person for each sampling followed a negative binomial distribution, thus showing aggregation. One method found a common aggregation parameter (k) for the negative binomial distribution, a finding that enabled the application of a sequential sampling method requiring few samples to determine whether the number of pupae/person was above a vector density threshold for dengue transmission. A second approach used the finding that the mean number of pupae/person is correlated with the proportion of pupa-infested households and calculated equivalent threshold proportions of pupa-positive households. A sequential sampling program was also developed for this method to determine whether observed proportions of infested households were above threshold levels. These methods can be used to validate entomological thresholds for dengue transmission.

Changes in polyamine levels in various organs of Bombyx mori during its life cycle.

PubMed

Hamana, K; Matsuzaki, S; Inoue, K

1984-06-01

Polyamines in various organs of larval, pupal, and moth stages of Bombyx mori, were assayed by high-performance ion-exchange chromatography and paper and thin-layer chromatography. Putrescine and spermidine were especially abundant in the silk gland, gonads, mucous gland, and sucking stomach; spermine was also present in them, but at much lower concentrations. Both norspermidine and norspermine were detected in almost all organs examined, while their precursor 1,3-diaminopropane was found only in a limited number of organs. Low concentrations of sym-homospermidine were observed in the silk gland and ovary. Cadaverine content was particularly high in the mucous gland which contained diapause eggs and the sucking stomach. Diapause eggs contained much higher levels of cadaverine than non-diapause eggs. The concentrations of most polyamines in the silk glands remained rather constant during the larval stage, and decreased markedly at the pupal stage. Polyamines in gonads, in contrast, did not decrease at the pupal stage, but putrescine, diaminopropane, and norspermidine rather increased during the pupal and moth stages.

Sex-dependent effects of larval food stress on adult performance under semi-natural conditions: only a matter of size?

PubMed

Rosa, Elena; Saastamoinen, Marjo

2017-07-01

Organisms with complex life-cycles acquire essential nutrients as juveniles, and hence even a short-term food stress during development can impose serious fitness costs apparent in adults. We used the Glanville fritillary butterfly to investigate the effects of larval food stress on adult performance under semi-natural conditions in a population enclosure. We were specifically interested in whether the negative effects observed were due to body mass reduction only or whether additional effects unrelated to pupal mass were evident. The two sexes responded differently to the larval food stress. In females, larval food stress reduced pupal mass and reproductive performance. The reduced reproductive performance was partially mediated by pupal mass reduction. Food stressed females also had reduced within-patch mobility, and this effect was not dependent on pupal mass. Conversely, food stress had no effect on male pupal mass, suggesting a full compensation via prolonged development time. Nonetheless, food stressed males were less likely to sire any eggs, potentially due to changes in their territorial behavior, as indicated by food stress also increasing male within-patch mobility (i.e., patrolling behavior). When males did sire eggs, the offspring number and viability were unaffected by male food stress treatment. Viability was in general higher for offspring sired by lighter males. Our study highlights how compensatory mechanisms after larval food stress can act in a sex-specific manner and that the alteration in body mass is only partially responsible for the reduced adult performance observed.

Estimating dengue vector abundance in the wet and dry season: implications for targeted vector control in urban and peri-urban Asia

PubMed Central

Wai, Khin Thet; Arunachalam, Natarajan; Tana, Susilowati; Espino, Fe; Kittayapong, Pattamaporn; Abeyewickreme, W; Hapangama, Dilini; Tyagi, Brij Kishore; Htun, Pe Than; Koyadun, Surachart; Kroeger, Axel; Sommerfeld, Johannes; Petzold, Max

2012-01-01

Background Research has shown that the classical Stegomyia indices (or “larval indices”) of the dengue vector Aedes aegypti reflect the absence or presence of the vector but do not provide accurate measures of adult mosquito density. In contrast, pupal indices as collected in pupal productivity surveys are a much better proxy indicator for adult vector abundance. However, it is unknown when it is most optimal to conduct pupal productivity surveys, in the wet or in the dry season or in both, to inform control services about the most productive water container types and if this pattern varies among different ecological settings. Methods A multi-country study in randomly selected twelve to twenty urban and peri-urban neighborhoods (“clusters”) of six Asian countries, in which all water holding containers were examined for larvae and pupae of Aedes aegypti during the dry season and the wet season and their productivity was characterized by water container types. In addition, meteorological data and information on reported dengue cases were collected. Findings The study reconfirmed the association between rainfall and dengue cases (“dengue season”) and underlined the importance of determining through pupal productivity surveys the “most productive containers types”, responsible for the majority (>70%) of adult dengue vectors. The variety of productive container types was greater during the wet than during the dry season, but included practically all container types productive in the dry season. Container types producing pupae were usually different from those infested by larvae indicating that containers with larval infestations do not necessarily foster pupal development and thus the production of adult Aedes mosquitoes. Conclusion Pupal productivity surveys conducted during the wet season will identify almost all of the most productive container types for both the dry and wet seasons and will therefore facilitate cost-effective targeted interventions. PMID:23318235

The occurrence of the cicada Cicadatra persica on apple trees, Malus domestica, in Erneh, Syria.

PubMed

Dardar, Marah A; Belal, Hamzeh M R; Basheer, Abedlnabi M

2013-01-01

An infestation of Cicadatra persica KirKaldy (Hemiptera: Cicadidae) on apple trees, Malus domestica Borkhausen (Rosales: Rosaceae), was reported for the first time in the apple fruit orchards of Erneh, Syria. Nymphs, adults, exuvia, and exit holes in the soil were observed. The species was identified as C. persica based on morphological characters. Some biological observations and an acoustic analysis of the male's songs were also achieved.

Comparison of the olfactory preferences of four species of filth fly pupal parasitoid species (Hymenoptera: Pteromalidae) for hosts in equine and bovine manure

USDA-ARS?s Scientific Manuscript database

House flies (Musca domestica L.) and stable flies (Stomoxys calcitrans (L.)) (Diptera: Muscidae) are common pests in equine and cattle facilities. Pupal parasitoids primarily in the genera Spalangia and Muscidifurax (Hymenoptera: Pteromalidae) can be purchased for biological control of these flies. ...

A Venom Gland Extracellular Chitin-Binding-Like Protein from Pupal Endoparasitoid Wasps, Pteromalus Puparum, Selectively Binds Chitin

USDA-ARS?s Scientific Manuscript database

Chitin-binding proteins (CBPs) existed in various species and involved in different biology processes. In the present study, we cloned a full length cDNA of chitin-binding protein-like (PpCBP-like) from Pteromalus puparum, a pupal endoparasitoid of Pieris rapae. PpCBP-like encoded a 96 putative amin...

Distribution of larval and pupal stages of Simulium (Diptera: Simuliidae) flies in the Nilgiris hills of Tamil Nadu.

PubMed

Soundararajan, C; Nagarajan, K; Arul Prakash, M

2017-09-01

Endemicity of onchocerciasis (river blindness) in humans is linked to the location of Simulium spp. (black fly). The distribution of immature stages of Simulium in Sholur, Pykara, Gudalur, Coonoor and Kotagiri streams of the Nilgiris hills of Tamil Nadu was investigated during the months of May and July 2012. Out of these five streams, only Sholur was infested with larval and pupal stages of Simulium spp. Out of six plants collected from various water bodies, larval and pupal stages were found on the leaves and stems of an aquatic plant Nasturtium officinale and on the roots and leaves of Pennisetum glandulosum. The stages of Simulium were observed only during the summer month of May.

In situ protocol for butterfly pupal wings using riboprobes.

PubMed

Ramos, Diane; Monteiro, Antonia

2007-01-01

Here we present, in video format, a protocol for in situ hybridizations in pupal wings of the butterfly Bicyclus anynana using riboprobes. In situ hybridizations, a mainstay of developmental biology, are useful to study the spatial and temporal patterns of gene expression in developing tissues at the level of transcription. If antibodies that target the protein products of gene transcription have not yet been developed, and/or there are multiple gene copies of a particular protein in the genome that cannot be differentiated using available antibodies, in situs can be used instead. While an in situ technique for larval wing discs has been available to the butterfly community for several years, the current protocol has been optimized for the larger and more fragile pupal wings.

A multi-proxy paleolimnological reconstruction of Holocene climate conditions in the Great Basin, United States

NASA Astrophysics Data System (ADS)

Reinemann, Scott A.; Porinchu, David F.; Bloom, Amy M.; Mark, Bryan G.; Box, Jason E.

2009-11-01

A sediment core spanning ˜ 7000 cal yr BP recovered from Stella Lake, a small sub-alpine lake located in Great Basin National Park, Nevada, was analyzed for subfossil chironomids (non-biting midges), diatoms, and organic content (estimated by loss-on-ignition (LOI)). Subfossil chironomid analysis indicates that Stella Lake was characterized by a warm, middle Holocene, followed by a cool "Neoglacial" period, with the last two millennia characterized by a return to warmer conditions. Throughout the majority of the core the Stella Lake diatom-community composition is dominated by small, periphytic taxa which are suggestive of shallow, cool, alkaline, oligotrophic waters with extensive seasonal ice cover. A reconstruction of mean July air temperature (MJAT) was developed by applying a midge-based inference model for MJAT (two-component WA-PLS) consisting of 79 lakes and 54 midge taxa ( rjack2 = 0.55, RMSEP = 0.9°C). Comparison of the chironomid-inferred temperature record to existing regional paleoclimate reconstructions suggests that the midge-inferred temperatures correspond well to regional patterns. This multi-proxy record provides valuable insight into regional Holocene climate and environmental conditions by providing a quantitative reconstruction of peak Holocene warmth and aquatic ecosystem response to these changes in the Great Basin, a region projected to experience increased aridity and higher temperatures.

Mouthpart deformities in Chironomidae (Diptera) as bioindicators of heavy metals pollution in Shiroro Lake, Niger State, Nigeria.

PubMed

Arimoro, Francis O; Auta, Yohanna I; Odume, Oghenekaro N; Keke, Unique N; Mohammed, Adamu Z

2018-03-01

In this study, mouthpart deformities in Chironomid larvae (Diptera) were investigated in relation to sediment contamination in the Shiroro Lake in Nigeria. Metals and chironomids were sampled monthly at three stations (A-C) between August 2013 and January 2014. Across the stations, zinc ranged (3.9-75mg/g), manganese (1.29-1.65mg/g), lead (0.00-0.10mg/g), iron (101-168mg/g) and copper (0.13-0.17mg/g). The metal ions did not differ significantly (P > 0.05) between the sampling stations. However, zinc and iron ions were significantly different between the sampling seasons (P < 0.05). Thirteen chironomid species were recorded, with Chironomus sp., Polypedilum sp. and Ablabesmyia sp. dominating the assemblage structure. Mouthpart deformities were significantly higher at Station A compared with Station C, and seasonally significantly higher during dry season compared with wet season. Elevated incidences of deformity were recorded in Chironomus spp larvae as compared to other genera therefore for further studies in this region assessments should be based solely on Chironomus species and ignoring the rest. Strategies need to be developed to reduce the contaminations and the biological effects. Copyright © 2017 Elsevier Inc. All rights reserved.

Does Nature and Persistence of Substrate at a Mesohabitat Scale Matter for Chironomidae Assemblages? a Study of Two Perennial Mountain Streams in Patagonia, Argentina

PubMed Central

Epele, Luis Beltrán; Miserendino, María Laura; Brand, Cecilia

2012-01-01

Chironomid substrate—specific associations regarding the nature (organic—inorganic) and stability (stable—unstable) of different habitats were investigated at two low order Patagonian streams, during high and low water periods. Nant y Fall and Glyn rivers were visited twice (October 2007 and March 2008) and seven different habitat types were identified. A total of 60 samples were collected using a Surber sampler (0.09 m -2 and 250 µm) and a set of 23 environmental descriptors including physicochemical parameters and different fractions of particulate organic matter were assessed. 35 Chironomidae taxa were recorded with Orthocladiinae (20), Chironominae (7), and Podonominae (4) being the most well—represented subfamilies. Paratrichocladius sp. 1, Parapsectrocladius sp. 2, Parametriocnemus sp. 1, Pseudochironomus sp., and Rheotanytarsus sp. were the most abundant taxa. According to the relative preference index, at least 14 taxa showed strong affinity for a particular substrate. The structurally complex macrophyte Myriophyllum quitense supported 11 taxa compared with only five taxa found on the less complex Isoetes savatieri. Generally, stable substrates (boulders, cobbles, and rooted plants) supported significantly higher chironomids richness, abundance, and diversity than unstable ones (gravel—sand). Canonical correspondence analysis revealed that detritus (leaves, seeds, and biomass), macrophyte biomass, and secondarily hydraulic variables had high explanatory power on chironomids species composition and structure. This work suggests that more complex substrates showing persistence in the temporal dimension supported a diverse array of chironomids, meaning that the maintenance of natural habitat heterogeneity is essential for the community. Land—use practices having significant effects on ecological stream attributes such as increased turbidity, sediment deposition, and runoff patterns will alter assemblages. Understanding environmental associations of the Chironomidae assemblage at the habitat scale is significant for conservation purposes and for the management of low order streams in Patagonia. PMID:22947060

Diversity and structure of Chironomidae communities in relation to water quality differences in the Swartkops River

NASA Astrophysics Data System (ADS)

Odume, O. N.; Muller, W. J.

The Swartkops River is an important freshwater ecosystem in South Africa. But owing to its location, it suffers varying degrees of human induced impacts which include industrial and domestic effluent discharges, deforestation as well as agricultural land use which have negatively impacted on the water quality. Diversity and community composition of aquatic insects are frequently used to assess environmental water quality status. Chironomids occupy extremely varied biotopes. Their extraordinary ecological range and environmental sensitivity make them particularly useful for assessing and interpreting changes in water quality of aquatic ecosystems. The community structure of chironomid larvae was investigated at four sites in the Swartkops River and effects of different chemical and physical variables on their distribution were explored. Chironomid larvae were collected using the South African Scoring System version 5 (SASS5) protocol. A total of 26 taxa from four sampling sites in the Swartkops River were identified. Margalef’s species richness index, equitability, Shannon and Simpson diversity indices were highest at site 1 (reference site). The downstream sites contained 6-20 taxa compared to the 25 taxa at site 1. Site 1 was characterised by the subfamilies Orthocladiinae, Tanypodinae and the tribe Tanytarsini while the impacted sites were characterised by Orthocladiinae and Chironomini. Chironomus spp., Dirotendipes sp., Kiefferulus sp. and Tanypus sp. seemed to be tolerant to pollution, occurring in high abundance at sites 2, 3 and 4. In contrast, Polypedilum sp., Tanytarsus sp., Orthocladius sp., Cricotopus spp. and Ablabesmyia sp. appeared to be more sensitive taxa, being less common at the impacted sites (sites 2, 3 and 4). Five days biochemical oxygen demand, dissolved oxygen, electrical conductivity, orthophosphate-phosphorus and total inorganic nitrogen were among the important variables that determine the observed chironomid community structure. Results revealed that the family Chironomidae, identified to species or genus, can be use to assess environmental water quality status in South African freshwater ecosystems.

Effects of dam construction and increasing pollutants on the ecohydrological evolution of a shallow freshwater lake in the Yangtze floodplain.

PubMed

Zeng, Linghan; McGowan, Suzanne; Cao, Yanmin; Chen, Xu

2018-04-15

Large river-floodplain systems which provide a variety of societal, economic and biological benefits are undergoing extensive and intensive human disturbance. However, floodplain lakes responses to multiple stressors are poorly understood. The Yangtze River and its floodplain which provide water and food resources for more than 300 million people are an important region in China. Hydrological regulation as well as socio-economic development have brought profound negative influence on this ecologically important area. To improve understanding of decadal-scale responses of floodplain lakes to multiple stressors, lake sediment proxies including particle size, geochemical elements, diatoms and chironomids were analysed in a lead-210 dated core from Futou Lake. The analyses show that dams constructed in 1935 and the early 1970s stabilized hydrological conditions in Futou Lake and impeded the interaction with the Yangtze River, resulting in a decrease in major elements (e.g., Mg, Al, Fe) transported into the lake and an increase of macrophyte-related chironomids (C. sylvestris-type, P. penicillatus-type and Paratanytarsus sp.). After the late 1990s, further decreases in major elements and increases in median grain size are attributed to the erosion of the Yangtze riverbed and declining supply of major elements-enriched sediments from the upper Yangtze caused by the impoundment of the Three Gorges Dam. Chironomid and diatom assemblages indicate that hydrological stabilization caused by dam constructions stimulated the growth of macrophytes, which may be important in buffering against an ecosystem state change towards a phytoplankton-dominated and turbid state with ongoing eutrophication. However, a recent increase in Zn, TP and the emergence of eutrophic diatom and chironomid species indicate initial signs of water quality deterioration which may be related to the combined effects of hydrological stabilization and aquaculture. Over all, the sediment record from Futou Lake emphasizes the importance of interactions between hydrological change and pollutant loads in determining floodplain lake ecosystem state. Copyright © 2017 Elsevier B.V. All rights reserved.

Late Quaternary Environmental Changes Inferred from the stable Oxygen Isotope Composition of Aquatic Insects (Chironomidae: Diptera) and Stable Hydrogen Isotope Composition of bulk sediments from Idavain Lake, Southwest Alaska

NASA Astrophysics Data System (ADS)

Wang, Y.; Finney, B.; Wooller, M. J.

2007-12-01

Several techniques are available to examine the isotopic composition of historic lake waters, providing data that can subsequently be used to examine environmental changes. Recently-developed techniques are the stable oxygen isotope analysis of subfossil chironomid (Diptera: Chironomidae) head capsules (mostly chitin) preserved in lake sediments and stable hydrogen isotope analyses directly on bulk sediments. An advantage of using δ18O of chironomids is that the chitinous chironomid headcapsules preserve well in lake sediments, retaining the stable oxygen isotope signature of the lake in which they lived. An advantage of δD analyses of bulk sediments is that a sediment core can be analyzed relatively easily and when the %C (total organic carbon) and %H profiles correlate the data can be used to infer past δD changes of the organics in the sediments. We present results from these analyses of a lake sediment core from Idavain Lake (58°46'N, 155°57'W, 223m above sea level) in southwest Alaska in concert with other paleolimnological proxies, including δ15N, δ13C, LOI, magnetic susceptibility, organic content and opal concentrations for a better understanding of paleolimnological changes since deglaciation for the region. Our preliminilary result shows that downcore shifts of δ18O analyzed from chironomid head capsules coincide well with LOI and pollen changes. The δD of sediments and TOM showed large magnitude changes and reflected the relative lake level changes during the record. This study aim to test the correlation between stable isotope analyese on chiornomid head capsules, lake water, and bulk sediments. In the addition, our study will add to the relatively small database of paleoenvironmental reconstructions from terrestrial sites in Southwest Alaska.

Changing perspectives on the importance of urban phosphorus inputs as the cause of nutrient enrichment in Lough Neagh.

PubMed

Foy, R H; Lennox, S D; Gibson, C E

2003-07-01

The scale and chronology of the phosphorus (P) enrichment of Lough Neagh, a large hypertrophic lake, was assessed using, as enrichment proxies, published palaeocological studies on diatoms and chironomid head capsules preserved in the lake sediments and, from 1974, monitoring data from the lake and its inflowing rivers. Enrichment commenced in 1880, and the scale and chronology of the diatom and chironomid records were similar up to 1960, but in the 1960s, chironomid accumulation rates increased dramatically, whereas diatom rates remained unchanged. From subsequent lake monitoring, the absence of a diatom response after 1960 was attributed to silica limitation so that P could be considered as the driver of increased diatom production only up to 1960. Using a coefficient for the demand for P by diatoms of 4 microg P mg SiO(2)(-1), it was calculated that the increased diatom production between 1881 and 1961 required an increase in lake P of 26 microg P l(-1). This value is close to the predicted increase of 22.5 microg P l(-1) in the lake caused by inputs of P from sewage treatment works and septic tanks. There was no evidence that diffuse source P contributed to enrichment over this period. Enrichment up to 1960 appears modest in comparison to subsequent years. From 1961 to 1974, lake P was estimated to have increased by 62 microg P l(-1), but only 25 microg P l(-1) of this increase was attributable to greater loadings of P from urban and septic tank sources. The enrichment response of chironomids at this time was also much greater than expected from a regression-derived relationship between urban P inputs and chironomid accumulation rates suggesting additional sources of P. The larger than expected increase in lake P was attributed to the onset of a significant internal loading of P and the commencement of an increase in diffuse source loadings of P. River monitoring has shown that diffuse P has increased steadily since 1974, more than counterbalancing a 40% reduction in urban P loadings that has taken place since 1980. By the end of the 20th century urban sources contributed only 19.7% of inflow P to Lough Neagh but lake P was 145 microg P l(-1) compared to an estimated concentration of 20 microg P l(-1) in 1881. Failure to control diffuse P sources has therefore been instrumental in the continued increase of lake P in Lough Neagh.

Composition of the Essential Oil of Salvia ballotiflora (Lamiaceae) and Its Insecticidal Activity.

PubMed

Cárdenas-Ortega, Norma Cecilia; González-Chávez, Marco Martín; Figueroa-Brito, Rodolfo; Flores-Macías, Antonio; Romo-Asunción, Diana; Martínez-González, Diana Elizabeth; Pérez-Moreno, Víctor; Ramos-López, Miguel Angel

2015-05-05

Essential oils can be used as an alternative to using synthetic insecticides for pest management. Therefore, the insectistatic and insecticidal activities of the essential oil of aerial parts of Salvia ballotiflora (Lamiaceae) were tested against the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae). The results demonstrated insecticidal and insectistatical activities against this insect pest with concentrations at 80 µg·mL(-1) resulting in 20% larval viability and 10% pupal viability. The larval viability fifty (LV50) corresponded to a concentration of 128.8 µg·mL(-1). This oil also increased the duration of the larval phase by 5.5 days and reduced the pupal weight by 29.2% withrespect to the control. The GC-MS analysis of the essential oil of S. ballotiflora showed its main components to be caryophyllene oxide (15.97%), and β-caryophyllene (12.74%), which showed insecticidal and insectistatical activities against S. frugiperda. The insecticidal activity of β-caryophyllene began at 80 µg·mL(-1), giving a larval viability of 25% and viability pupal of 20%. The insectistatic activity also started at 80 µg·mL(-1) reducing the pupal weight by 22.1% with respect to control. Caryophyllene oxide showed insecticidal activity at 80 µg·mL(-1) giving a larval viability of 35% and viability pupal of 20%.The insectistatic activity started at 400 µg·mL(-1) and increased the larval phase by 8.8% days with respect to control. The LV50 values for these compounds were 153.1 and 146.5 µg·mL(-1), respectively.

Effects of pathogen exposure on life history variation in the gypsy moth (Lymantria dispar)

PubMed Central

Páez, David J.; Fleming-Davies, Arietta E.; Dwyer, Greg

2015-01-01

Investment in host defenses against pathogens may lead to tradeoffs with host fecundity. When such tradeoffs arise from genetic correlations, rates of phenotypic change by natural selection may be affected. However, genetic correlations between host survival and fecundity are rarely quantified. To understand tradeoffs between immune responses to baculovirus exposure and fecundity in the gypsy moth (Lymantria dispar), we estimated genetic correlations between survival probability and traits related to fecundity, such as pupal weight. In addition, we tested whether different virus isolates have different effects on male and female pupal weight. To estimate genetic correlations, we exposed individuals of known relatedness to a single baculovirus isolate. To then evaluate the effect of virus isolate on pupal weight, we exposed a single gypsy moth strain to 16 baculovirus isolates. We found a negative genetic correlation between survival and pupal weight. In addition, virus exposure caused late-pupating females to be identical in weight to males, whereas unexposed females were 2–3 times as large as unexposed males. Finally, we found that female pupal weight is a quadratic function of host mortality across virus isolates, which is likely due to tradeoffs and compensatory growth processes acting at high and low mortality levels, respectively. Overall, our results suggest that fecundity costs may strongly affect the response to selection for disease resistance. In nature, baculoviruses contribute to the regulation of gypsy moth outbreaks, as pathogens often do in forest-defoliating insects. We therefore argue that tradeoffs between host life-history traits may help explain outbreak dynamics. PMID:26201381

A Holocene temperature reconstruction from northern New Zealand: a test of North Atlantic Holocene climate patterns as a global template

NASA Astrophysics Data System (ADS)

van den Bos, Valerie; Rees, Andrew; Newnham, Rewi; Augustinus, Paul

2017-04-01

Holocene climate variability has been well defined in the North Atlantic (Walker et al., 2012), but the global extent of this climate change stratigraphy is debatable. If the North Atlantic serves as a global template for Holocene climate, then New Zealand (NZ) is ideally positioned to test this assertion, as it is distal from the northern drivers. Additionally, it is one of the few landmasses in the Southern Hemisphere that is influenced by both sub-tropical and extra-tropical climatic regimes, which may be more important controls in the southern mid-latitudes. Although much work has been done to characterise the Holocene in NZ using pollen, most of these records lack the resolution or sensitivity to determine whether abrupt or short-lived events occurred. The NZ-INTIMATE climate event stratigraphy lacks a type section for the Holocene (Alloway et al., 2007). Records from northern NZ typically show little change, other than a possible early Holocene warming. Here, we present a combined pollen and chironomid temperature reconstruction from Lake Pupuke (northern NZ), the first of its kind in NZ that covers the entire Holocene. By comparing mean annual temperatures reconstructed from fossil pollen and mean summer temperatures inferred from chironomid remains, we can assess changes in seasonality. Mean summer temperature was reconstructed from the chironomid record using a weighted averaging partial least squares (WA-PLS) model (n comp = 2, r2booth = 0.77, RMSEP = 1.4°C) developed from an expanded version of Dieffenbacher-Krall et al. (2007)'s chironomid training set. Preliminary results show evidence for cool summers during the early Holocene as well as around the period of the Little Ice Age as defined in the North Atlantic region. These and other climate patterns determined from the Pupuke chironomid and pollen records will be compared with other evidence from northern New Zealand and with the North Atlantic record of Holocene climate variability. References: Alloway, B.V., Lowe, D.J., Barrell, D.J.A., Newnham, R.M., Almond, P.C., Augustinus, P.C., Bertler, N.A.N., Carter, L., Litchfield, N.J., McGlone, M.S., Shulmeister, J., Vandergoes, M.J., Williams, P.W., and NZ-INTIMATE members. 2007. Towards a climate event stratigraphy for New Zealand over the past 30 000 years (NZ-INTIMATE project). Journal of Quaternary Science, 22, 9-35. Dieffenbacher-Krall, A.C., Vandergoes, M.J., Denton, G.H. 2007. An inference model for mean summer air temperatures in the Southern Alps, New Zealand, using subfossil chironomids. Quaternary Science Reviews, 26, 2587-2504. Walker, M.J.C., Berkelhammer, M., Björck, S., Cwynar, L.C., Fisher, D.A., Long, A.J., Lowe, D.J., Newnham, R.M., Rasmussen, S.O., Weiss, H. 2012. Formal subdivision of the Holocene Series/Epoch: a discussion paper by a working group of INTIMATE (Integration of ice-core, marine and terrestrial records) and the Subcommission on Quaternary Stratigraphy (International Commission on Stratigraphy). Journal of Quaternary Science, 27, 649-659.

Anhydrobiosis vs. aging: comparative genomics of protein repair L-isoaspartyl methyltransferases in the sleeping chironomid. .

NASA Astrophysics Data System (ADS)

Gusev, Oleg; Kikawada, Takahiro; Shagimardanova, Elena; Suetsugu, Yoshitaka; Ayupov, Rustam

Origin of anhydrobiosis in the larvae of the sleeping chironomid Polypedilum vanderplanki represents unique example of set of evolutionary events in a single species, resulted in acquiring new ability allowing survival in extremely changeable environment. Complex comparative analysis of the genome of P. vanderplanki resulted in discovery of a set of features, including existence of the set of unique clusters of genes contributing in desiccation resistance. Surprisingly, in several cases, the genes mainly contributing to the formation of the molecular shield in the larvae are sleeping chironomid-specific and have no homology with genes from other insects, including P. nubifer - a chironomid from the same genus. Protein L-isoaspartyl methyltransferase (PIMT) acts on proteins that have been non-enzymatically damaged due to age, and partially restores aspartic residues, extending life of the polypeptides. PIMT a highly conserved enzyme present in nearly all eukaryotes, and microorganisms mostly in a single copy (or in a few isoforms in certain plants and some bacteria). While conducting a comparative analysis of the genomes of two chironomid midge species different in their ability to stand complete water loss, we have noticed that structure and number of PIMT-coding genes in the desiccation resistant (anhydrobiotic) midge (Polypedilum vanderplanki, Pv) is different from those of the common desiccation-sensitive midge (Polypedilum nubifer, Pn) and the rest of insects. Both species have a clear orthologous PIMT shared by all insects. At the same time, in contrast to Pn which has only one PIMT gene (PnPimt-1), the Pv genome contains 12 additional genes paralogous to Pimt1 (PvPimt-2-12) presumably coding functional PIMT proteins, which are arranged in a single cluster. Remarkably, PvPimt-1 location in the Pv is different from the rest of Pimt-like genes. PvPimt-1 gene is ubiquitously expressed during the life cycle, but expression of the PvPimt2-12 is limited to the eggs and larval stages. Finally, the expression of Pimt1 gene in both chironomids was not changed in response to desiccation, while the clustered PvPimt2-12 showed strong up-regulation in response to water loss and other abiotic stresses. The abundance of PvPimt2-12 mRNAs was maximal in anhydrobiotic larvae, and it resembles the case of plant seeds where accumulation of PIMT provides additional protection for proteins during long dry storage. Predicted proteins of PvPimT2-12 contain conservative L-isoaspartyl methyltransferase functional domain. At the same time the length and structure of N- and C- terminals of the predicted proteins show significant variation, suggesting different substrate preferences or other specific properties of different Pv-PIMT Furthermore, the multi-member family in Pv is the first observation of drastic expansion and evolution of Pimt genes in general, and particularly in a single insect species. This work was supported by Russian Foundation for Basic Research (No. 12-08-33157 mol_a_ved and No. 14-04-01657_A).

Redescription of Four Oriental Species of Culex (Culiciomyia) and the Description of a New Species from Thailand (Diptera: Culicidae)

DTIC Science & Technology

1977-01-01

Holotype d (05670-6) with associated pupal and larval skins and genitalia slide, rock pool, inside a cave; Chiang Dao, Chiang Mai , THAI- LAND, 11 December...from Chiang Mai , Thailand. Material examined. 104 16 d, 21 9, 45 L; 37 individual rearings (17 larval, 20 pupal). THAILAND. Chiang Mai : Chiang Dao

The Occurrence of the Cicada Cicadatra persica on Apple Trees, Malus domestica, in Erneh, Syria

PubMed Central

Dardar, Marah A.; Belal, Hamzeh M.R.; Basheer, Abedlnabi M.

2013-01-01

An infestation of Cicadatra persica KirKaldy (Hemiptera: Cicadidae) on apple trees, Malus domestica Borkhausen (Rosales: Rosaceae), was reported for the first time in the apple fruit orchards of Erneh, Syria. Nymphs, adults, exuvia, and exit holes in the soil were observed. The species was identified as C. persica based on morphological characters. Some biological observations and an acoustic analysis of the male's songs were also achieved. PMID:23909877

Mineral in skeletal elements of the terrestrial crustacean Porcellio scaber: SRμCT of function related distribution and changes during the moult cycle.

PubMed

Ziegler, Andreas; Neues, Frank; Janáček, Jiří; Beckmann, Felix; Epple, Matthias

2017-01-01

Terrestrial isopods moult first the posterior and then the anterior half of the body, allowing for storage and recycling of CaCO 3 . We used synchrotron-radiation microtomography to estimate mineral content within skeletal segments in sequential moulting stages of Porcellio scaber. The results suggest that all examined cuticular segments contribute to storage and recycling, however, to varying extents. The mineral within the hepatopancreas after moult suggests an uptake of mineral from the ingested exuviae. The total maximum loss of mineral was 46% for the anterior and 43% for the posterior cuticle. The time course of resorption of mineral and mineralisation of the new cuticle suggests storage and recycling of mineral in the posterior and anterior cuticle. The mineral in the anterior pereiopods decreases by 25% only. P. scaber has long legs and can run fast; therefore, a less mineralised and thus lightweight cuticle in pereiopods likely serves to lower energy consumption during escape behaviour. Differential demineralisation occurs in the head cuticle, in which the cornea of the complex eyes remains completely mineralised. The partes incisivae of the mandibles are mineralised before the old cuticle is demineralised and shed. Probably, this enables the animal to ingest the old exuviae after each half moult. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pupal vibratory signals of a group-living beetle that deter larvae

PubMed Central

Kojima, Wataru; Ishikawa, Yukio; Takanashi, Takuma

2012-01-01

Pupae of some insects produce sounds or vibrations, but the function of the sounds/vibrations has not been clarified in most cases. Recently, we found vibratory communication between pupae and larvae of a group-living beetle Trypoxylus dichotoma, which live in humus soil. The vibratory signals produced by pupae were shown to deter approaching larvae, thereby protecting themselves. In the present study, we tested our hypothesis that pupal signals are mimics of vibratory noises associated with foraging of moles, the most common predators of T. dichotoma. Mole vibrations played back in laboratory experiments deterred larval approaches in the same way as pupal signals. These findings suggest that to deter conspecific larvae, pupae of T. dichotoma may have exploited a preexisting response of larvae to predator vibrations by emitting deceptive signals. PMID:22896788

Aedes aegypti pupal/demographic surveys in southern Mexico: consistency and practicality.

PubMed

Arredondo-Jiménez, J I; Valdez-Delgado, K M

2006-04-01

In interventions aimed at the control of the immature stages of Aedes aegypti (L.), the principal vector of the dengue viruses, attempts are often made to treat or manage all larval habitats in households. When there are resource-constraints, however, a concentration of effort on the types of container that produce the most pupae may be required. Identification of these 'key' container types requires surveys of the immature stages and particularly - since these give the best estimates of the numbers of adults produced - of the numbers of pupae in local containers. Although there has been no clearly defined or standardized protocol for the sampling of Ae. aegypti pupae for many years, a methodology for 'pupal/demographic' surveys, which may allow the risk of dengue outbreaks in a given setting to be estimated, has been recently described. The consistency and practicality of using such surveys has now been investigated in three cities in the Mexican state of Chiapas, Mexico. Using a combination of 'quadrat'- and transect-sampling methods, 600 houses in each city were each sampled twice. Containers within each study household were searched for pupae and larvae. Although 107,297 containers, belonging to 26 categories, were observed, only 16,032 were found to contain water and 96% and 92% of these 'wet' containers contained no pupae and no third- or fourth-instar larvae, respectively. Although the random 'quadrat' sampling gave similar results to sampling along transects, there were statistically significant differences in the numbers of pupae according to container type and locality. The most important containers for pupal production were found to be large cement wash basins, which were present in almost every household investigated and from which 84% (10,257/12,271) of all pupae were collected. A focus on this class of container could serve as the basis of a targeted intervention strategy. When traditional Stegomyia indices were calculated they appeared to be correlated with the assessments of pupal abundance. The methodology for pupal/demographic surveys appears to be practical and to give consistent results, although it remains to be seen if monitoring of pupal productivity can adequately reflect the impact of vector-control interventions.

The influence of late-stage pupal irradiation and increased irradiated: un-irradiated male ratio on mating competitiveness of the malaria mosquito Anopheles arabiensis Patton.

PubMed

Helinski, M E H; Knols, B G J

2009-06-01

Competitiveness of released males in genetic control programmes is of critical importance. In this paper, we explored two scenarios to compensate for the loss of mating competitiveness after pupal stage irradiation in males of the malaria mosquito Anopheles arabiensis. First, competition experiments with a higher ratio of irradiated versus un-irradiated males were performed. Second, pupae were irradiated just prior to emergence and male mating competitiveness was determined. Males were irradiated in the pupal stage with a partially or fully-sterilizing dose of 70 or 120 Gy, respectively. Pupae were irradiated aged 20-26 h (young) as routinely performed, or the pupal stage was artificially prolonged by cooling and pupae were irradiated aged 42-48 h (old). Irradiated males competed at a ratio of 3:1:1 to un-irradiated males for mates in a large cage design. At the 3:1 ratio, the number of females inseminated by males irradiated with 70 Gy as young pupae was similar to the number inseminated by un-irradiated males for the majority of the replicates. At 120 Gy, significantly fewer females were inseminated by irradiated than by un-irradiated males. The irradiation of older pupae did not result in a significantly improved male mating competitiveness compared to the irradiation of young pupae. Our findings indicate that the loss of competitiveness after pupal stage irradiation can be compensated for by a threefold increase of irradiated males, but only for the partially-sterilizing dose. In addition, cooling might be a useful tool to facilitate handling processes of large numbers of mosquitoes in genetic control programmes.

Tri-trophic interactions between Bt cotton, the herbivore Aphis gossypii Glover (Homoptera: Aphididae), and the predator Chrysopa pallens (Rambur) (Neuroptera: Chrysopidae).

PubMed

Guo, Jian-Ying; Wan, Fang-Hao; Dong, Liang; Lövei, Gábor L; Han, Zhao-Jun

2008-02-01

Tri-trophic impacts of transgenic Bacillus thuringiensis (Bt) cotton GK12 and NuCOTN 99B were studied using a predator, the great lacewing Chrysopa pallens (Rambur), and its prey, the cotton aphid Aphis gossypii Glover, in laboratory feeding experiments. The parental nontransgenic cotton cultivar of GK12 was used as control. The predator was fed with uniform (aphids from a single cultivar) or mixed prey (aphids from the three cotton cultivars provided on alternate days). Mortality and development of the immature stages, pupal body mass, adult sex ratio, fecundity, and egg viability of C. pallens were measured. When fed GK12-originated aphid prey, pupal body mass of C. pallens was significantly higher than that of the control, more females emerged, and these females laid significantly more eggs. Other parameters were not impacted. Females emerging from larvae maintained on NuCOTN 99B-originated prey laid fewer eggs than those maintained on GK12. Other measurements did not differ significantly between the two Bt cotton cultivars. Compared with the control, mixed feeding significantly prolonged pupal development time and increased pupal body mass and percentage of females but did not affect other parameters. These results indicate that C. pallens is sensitive to aphid prey from different cotton cultivars. Transgenic Bt cotton GK12-originated aphid prey has no adverse impact on survival, development, and fecundity of C. pallens. Between the two Bt cotton cultivars, NuCOTN 99B-originated aphid prey provided to C. pallens in the larval stage may lower female fecundity. Mixed feeding of C. pallens with the two Bt cotton-originated prey and non-Bt prey may have some adverse impacts on pupal development.

Teratogenic versus mutagenic abnormalities in chironomid larvae exposed to zinc and lead.

PubMed

Martinez, Edward A; Moore, Barry C; Schaumloffel, John; Dasgupta, Nairanjana

2004-08-01

Before chironomid mouthpart deformities can be utilized as indicators of aquatic metal pollution with certainty, it must first be established that deformities are teratogenic and not mutagenic. A laboratory experiment was conducted to assess this question using Zn and Pb as causative agents. Parent populations were reared in sediments spiked with zinc (Zn) or lead (Pb) and their resulting offspring (F1 generation) were reared in clean sediments. The proportions of mouthpart deformities in C. tentans larvae were compared via logistic regression, accounting for time of exposure, between parent and offspring populations. Results indicate that 14% of chironomids from Zn-spiked sediment contained deformed menta and/or mandibles. However, the F1-Zn generation displayed a deformity of 1.7%. Larvae reared in Pb-spiked sediments displayed a deformity frequency of 9% and the F1 generations (F1-Pb a and F1-Pb b) had deformity proportion of 7 and 6%, respectively. We concluded that the deformities caused by Zn stress were morphological because the resulting F1 deformity frequencies declined to control levels. However, deformities caused by Pb appear to be genetic since F1 deformity percentages did not differ from the parent deformity frequency. Because larvae reared in Zn- and Pb-spiked sediments were larger than larvae reared in uncontaminated sediments, we could not conclude that Zn and Pb in the sediments stunted the development of C. tentans.

Contrasting responses to long-term climate change of carbon flows to benthic consumers in two different sized lakes in the Baltic area.

NASA Astrophysics Data System (ADS)

Belle, Simon; Freiberg, Rene; Poska, Anneli; Agasild, Helen; Alliksaar, Tiiu; Tõnno, Ilmar

2018-05-01

The study of lake sediments and archived biological remains is a promising approach to better understand the impacts of climate change on aquatic ecosystems. Small lakes have been shown to be strongly sensitive to past climate change, but similar information is lacking for large lakes. By identifying responses to climate change of carbon flows through benthic food web in two different sized lakes, we aimed to understand how lake morphometry can mediate the effects of climate change. We reconstructed the dynamics of phytoplankton community composition and carbon resources sustaining chironomid biomass during the Holocene from the combined analysis of sedimentary pigment quantification and carbon stable isotopic composition of subfossil chironomid head capsules (δ13CHC) in a large lake in the Baltic area (Estonia). Our results showed that chironomid biomass in the large lake was mainly sustained by phytoplankton, with no significant relationship between δ13CHC values and temperature fluctuations. We suggest that lake morphometry (including distance of the sampling zone to the shoreline, and lake volume for primary producers) mediates the effects of climate change, making large lakes less sensitive to climate change. Complementary studies are needed to better understand differences in organic matter dynamics in different sized lakes and to characterize the response of the aquatic carbon cycle to past climate change.

Near Infrared Imaging As a Method of Studying Tsetse Fly (Diptera: Glossinidae) Pupal Development

PubMed Central

Moran, Zelda R.; Parker, Andrew G.

2016-01-01

Abstract Near infrared (NIR) photography and video was investigated as a method for observing and recording intrapuparial development in the tsetse fly Glossina palpalis gambiensis and other Muscomorpha (Cyclorrhapha) Diptera. We showed that NIR light passes through the puparium, permitting images of the true pupae and pharate adult to be captured. Various wavelengths of NIR light from 880 to 1060 nm were compared to study the development of tsetse fly pupae from larviposition to emergence, using time-lapse videos and photographs. This study was carried out to advance our understanding of tsetse pupal development, specifically with the goal of improving a sorting technique which could separate male from female tsetse flies several days before emergence. Separation of the sexes at this stage is highly desirable for operational tsetse sterile insect technique control programmes, as it would permit the easy retention of females for the colony while allowing the males to be handled, irradiated and shipped in the pupal stage when they are less sensitive to vibration. In addition, it presents a new methodology for studying the pupal stage of many coarctate insects for many applications. NIR imaging permits observation of living pupae, allowing the entire development process to be observed without disruption. PMID:27402791

Host availability affects the interaction between pupal parasitoid Coptera haywardi (Hymenoptera: Diiapridae) and larval-pupal parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae).

PubMed

Montoya, P; Gálvez, C; Díaz-Fleischer, F

2018-02-12

The use of multiple species in biological control programmes is controversial when interactions among them are not fully understood. We determined the response of the pupal parasitoid Coptera haywardi (Oglobin) to different availability of Anastrepha ludens (Loew) pupae previously parasitized or not by larval-pupal Diachasmimorpha longicaudata (Ashmead). The two types of pupae were exposed at different ages and proportions to different numbers of C. haywardi females for 48 h. The performance of C. haywardi adults emerging from parasitized and unparasitized pupae was measured. Coptera haywardi prefers to attack unparasitized A. ludens pupae rather than pupae parasitized by D. longicaudata. However, when the availability of unparasitized pupae was low or the number of foraging females was high, C. haywardi competed against early immature stages of the D. longicaudata, or hyperparasitized, feeding directly on the advanced-immature developmental stages of the early acting species. Adults of C. haywardi emerging as hyperparasitoids were no different in size, fecundity and longevity from those emerging as primary parasitoids. Our data suggest that simultaneous use of these species in augmentative biological control projects may be feasible but should be carefully planned in order to avoid any detrimental effect of its interaction.

Multi-proxy evidence for climate-driven changes in arctic lakes from northern Russia over the Holocene.

NASA Astrophysics Data System (ADS)

Self, Angela; Brooks, Stephen; Jones, Vivienne; Solovieva, Nadia; McGowan, Suzanne; Rosén, Peter; Parrott, Emily; Seppä, Heikki; Salonen, Sakari

2010-05-01

Average arctic temperatures have increased at almost twice the rate of the rest of the world over the last 100 years and climate projections suggest this trend is likely to continue resulting in an additional warming of 2 - 3°C in annual mean air temperatures by 2050. Freshwater ecosystems occupy a substantial area of the terrestrial environment in the Arctic and are particularly sensitive to temperature increases which may lead to profound changes in catchment characteristics, permafrost, hydrology and nutrient availability. Therefore it is important to understand how past changes in climate have affected these ecosystems. In this paper we present one of the first quantitative multi-proxy climate records from arctic Siberia. The affect of early - mid Holocene and recent climate change on arctic lakes in northern Russia were investigated in multi-proxy studies. The past climate was reconstructed using chironomid inference models to estimate mean July air temperatures and trends in continentality. Stable isotopes and LOI were analysed to infer past changes in sediment organic matter. Near-infrared spectroscopy (NIRS) and/or diatoms were used to infer changes in lake water total organic carbon and algal pigments and/or diatoms were used to infer changes in productivity and light penetration in the lake. Analyses of a sediment core from a tundra lake (Lake Kharinei) in north-eastern European Russia show significant assemblage changes in diatoms, chironomids and pigments, which coincide with climate-driven vegetation shifts from open birch forest to spruce forest and then to tundra over the Holocene. During the open birch phase of the late Glacial - early Holocene, chironomid-inferred reconstructions suggest that the climate was approximately 1 - 3°C warmer and more continental than present. Isotopic analyses indicate a productive environment receiving a significant input of organic material from terrestrial plants into the lake. Both diatoms and NIRS-TOC also suggest that the lake water was relatively high in TOC. Spruce forest became established within the catchment during the early - mid Holocene, which appears to have stimulated algal production. Throughout this period July air temperatures are inferred to have gradually declined to present-day values and the climate became more maritime. From ca. 4000 cal yrs BP July air temperatures remained stable but continentality increased leading to a shorter ice-free period. The pollen and macrofossil record indicates a transition to tundra vegetation ca 3000 cal yr BP which coincides with major changes in pigments, chironomids and diatoms. High resolution reconstruction of climate variability over the last 200 years from two tundra lakes on the Putoran Plateau, western Siberia, suggest that mean July air temperatures warmed by approximately 0.5°C between ca 1820 - 1980 and have remained relatively stable over the last 30 years. However major compositional changes in the chironomid and diatom assemblages have occurred within the last 125 - 50 years. Since the 1970s increases in the instrumental June temperature record and a chironomid-inferred shift to a more maritime climate have been accompanied by increases in diatom accumulation rates together with an increase in within-lake productivity and a trend towards increased algal productivity (as highlighted by stable isotope analysis). The synchronicity of the changes suggests the biota may be responding to lengthening of the ice-free period and related limnological changes. The changes in these Russian lakes corroborate results from Europe and Arctic Canada and indicate a circumpolar pattern of climate-driven regime change in arctic lakes in the last 100 years.

Reconstruction of full glacial environments and summer temperatures from Lago della Costa, a refugial site in Northern Italy

NASA Astrophysics Data System (ADS)

Samartin, Stéphanie; Heiri, Oliver; Kaltenrieder, Petra; Kühl, Norbert; Tinner, Willy

2016-07-01

Vegetation and climate during the last ice age and the Last Glacial Maximum (LGM, ∼23,000-19,000 cal BP) were considerably different than during the current interglacial (Holocene). Cold climatic conditions and growing ice-sheets during the last glaciation radically reduced forest extent in Europe to a restricted number of so-called ;refugia;, mostly located in the southern part of the continent. On the basis of paleobotanical analyses the Euganian Hills (Colli Euganei) in northeastern Italy have previously been proposed as one of the northernmost refugia of temperate trees (e.g. deciduous Quercus, Tilia, Ulmus, Fraxinus excelsior, Acer, Abies alba, Fagus sylvatica, Carpinus and Castanea) in Europe. In this study we provide the first quantitative, vegetation independent summer air temperature reconstruction for Northern Italy spanning the time ∼31,000-17,000 cal yr BP, which covers the coldest periods of the last glacial, including the LGM and Heinrich stadials 1 to 3. Chironomids preserved in a lake sediment core from Lago della Costa (7m a.s.l.), a small lake at the south-eastern edge of the Euganean Hills, allowed quantitative reconstruction of Full and Late Glacial summer air temperatures using a combined Swiss-Norwegian temperature inference model based on chironomid assemblages from 274 lakes. Chironomid and pollen evidence from Lago della Costa derives from finely stratified autochthonous organic gyttja sediments, which excludes major sediment mixing or reworking. After reconstructing paleo-temperatures, we address the question whether climate conditions were warm enough to permit the local survival of temperate tree species during the LGM and whether local expansions and pollen-inferred contractions of temperate tree taxa coincided with chironomid-inferred climatic changes. Our results suggest that chironomids at Lago della Costa have responded to major climatic fluctuations such as temperature decreases during the LGM and Heinrich stadials. The vegetation of the Euganean Hills shows responses to these climatic oscillations although the effects of temperature changes were probably also strongly influenced by changes in humidity. Reconstructed July air temperatures at Lago della Costa never fell below 10-13 °C (error range of reconstruction ∼ ±1.5-1.6 °C), which is considerably above the limit considered necessary for forest growth (8-10 °C). Instead rather mild climatic conditions prevailed ∼31,000-17,000 cal yr BP with average summer temperatures between ∼12 and 16 °C, which most likely allowed survival of temperate tree taxa in the warmest (and moistest) microhabitats of the Euganean Hills during the LGM. Only assuming local survival is it possible to explain the repeated expansions and collapses of temperate trees at Lago della Costa which faithfully accompanied the climatic oscillations.

Quantitative estimates of Mid- to late Holocene Climate Variability in northeastern Siberia inferred from chironomids in lake sediments

NASA Astrophysics Data System (ADS)

Nazarova, Larisa; Diekmann, Bernhard; Pestrjakova, Ludmila; Herzschuh, Ulrike; Subetto, Dmitry

2010-05-01

Yakutia (Russia, northeastern part of Eurasia) represents one of Earths most extreme climatic settings in the world with deep-reaching frozen ground and a semiarid continental climate with highest seasonal temperature contrasts in the northern hemisphere. The amplitude of temperature variations around the year sometimes exceeds 100oC. There are few examples of quantitative palaeoecological studies in Siberia and these data have to be tested by quantitative studies from other sites in this region, inferred from different proxies and using regional calibration datasets and temperature models that are still lacking. Chironomid midges (Insecta, Diptera, Chironomidae) have been widely used to reconstruct past climate variability in many areas of Western Europe and North America. A chironomid-mean July air temperature inference model has been developed, based on a modern calibration set of 200 lakes sampled along a transect from 110° to 159° E and 61° to73° N in northern Russia. The inference model was applied to sediment cores from 2 lakes in the Central Yakutia in order to reconstruct past July air temperatures. The lacustrine records span mid- to late Holocene. The downcore variability in the chironomid assemblages and the composition of organic matter give evidence of climate-driven and interrelated changes in biological productivity, lacustrine trophic states, and lake-level fluctuations. Three phases of the climate development in Central Yakutia can be derived from the geochemical composition of the lake cores and according to the inferred from chironomid assemblages mean July air ToC. Content of organic matters reached maximal values in the period between 7000-4500 yBP. Sedimentation rate is especially high, numerous molluscs shells are found in sediments. All this along with the reconstructed air temperature confirmed that Mid Holocene optimum in Central Yakutia took place in this period with the maximal temperatures up to 4oC above present day ToC. Strong faunistic changes take place after 4500 yBP. Temperature reconstruction has shown that around 4500 ka BP air temperature went down up to 2oC below modern temperature. These observations confirm end of Holocene climate optimum at this time. The lake status record reveals a long-term trend towards lake-level lowering in the course of climate deterioration after 4.2 cal. ka BP and reduced evaporation as well as progressive sediment infill. This long-term trend is overprinted by short-term fluctuations at centennial time scales with high lake levels and decreased biological productivity during cool climate spells with reduced evaporation, as also observed in modern thermokarst lakes of Central Yakutia.

Chironomid record of Late Quaternary climatic and environmental changes from two sites in Central Asia (Tuva Republic, Russia)—local, regional or global causes?

NASA Astrophysics Data System (ADS)

Ilyashuk, Boris P.; Ilyashuk, Elena A.

2007-03-01

Sediment cores from two mountain lakes (Lake Grusha at 2413 m a.s.l. and Ak-Khol at 2204 m a.s.l.) situated in the Tuva Republic (southern Siberia, Russia), just north of Mongolia, were studied for chironomid fossils in order to infer post-glacial climatic changes and to investigate responses of the lake ecosystems to these changes. The results show that chironomids are responding both to temperature and to changing lake depth, which is regarded as a sensitive proxy of regional effective moisture. The post-glacial history of this mountain region in Central Asia can be divided into seven successive climatic phases: the progressive warming during the last glacial-interglacial transition (ca 15.8-14.6 cal kyr BP), the warm and moist Bølling-Allerød-like interval (ca 14.6-13.1 cal kyr BP), the cool and dry Younger Dryas-like event (ca 13.1-12.1 cal kyr BP), warmer and wetter conditions during ca 12.1-8.5 cal kyr BP, a warm and dry phase ca 8.5-5.9 cal kyr BP, cold and wet conditions during ca 5.9-1.8 cal kyr BP, as well as cold and dry climate within the last 1800 years. The chironomid records reveal patterns of climatic variability during the Late-glacial and Holocene, which can be correlated with abrupt climatic events in the North Atlantic and the Asian monsoon-dominated regimes. Apparently, the water balance of the studied lakes is controlled by the interrelation between the dominant westerly system and the changing influence of the summer monsoon, as well as the influence of alpine glacier meltwater supply. It is possible that monsoon tracks could have reached the southwest Tuva, resulting in an increase in precipitation at ca 14.6-13.1 and ca 12.1-8.5 cal kyr BP, whereas cyclonic westerlies from the North Atlantic were likely responsible for considerable moisture transport accompanying the global Neoglacial cooling at ca 5.9-1.8 cal kyr BP. These events suggest the changes of the regional pattern of atmospheric circulation, which could be in turn induced by the global climatic shifts. Some discrepancies compared with other reconstructions from Central Asia may be associated with regional (spatial) differences between the changing predominant circulation mechanisms and with local differences in uplift and descent of air masses within the complicated mountain landscape. In this paper, we also discuss the possibilities and perspectives for using chironomids in reconstructions of past temperatures and climate-induced changes in water depth of lakes in Central Asia.

Drosophila arginine methyltransferase 1 (DART1) is an ecdysone receptor co-repressor

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

Kimura, Shuhei; Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574; Sawatsubashi, Shun

2008-07-11

Histone arginine methylation is an epigenetic marker that regulates gene expression by defining the chromatin state. Arginine methyltransferases, therefore, serve as transcriptional co-regulators. However, unlike other transcriptional co-regulators, the physiological roles of arginine methyltransferases are poorly understood. Drosophila arginine methyltransferase 1 (DART1), the mammalian PRMT1 homologue, methylates the arginine residue of histone H4 (H4R3me2). Disruption of DART1 in Drosophila by imprecise P-element excision resulted in low viability during metamorphosis in the pupal stages. In the pupal stage, an ecdysone hormone signal is critical for developmental progression. DART1 interacted with the nuclear ecdysone receptor (EcR) in a ligand-dependent manner, and co-repressedmore » EcR in intact flies. These findings suggest that DART1, a histone arginine methyltransferase, is a co-repressor of EcR that is indispensable for normal pupal development in the intact fly.« less

Supercritical Carbon Dioxide Extraction of the Oak Silkworm (Antheraea pernyi) Pupal Oil: Process Optimization and Composition Determination

PubMed Central

Pan, Wen-Juan; Liao, Ai-Mei; Zhang, Jian-Guo; Dong, Zeng; Wei, Zhao-Jun

2012-01-01

Supercritical carbon dioxide (SC-CO2) extraction of oil from oak silkworm pupae was performed in the present research. Response surface methodology (RSM) was applied to optimize the parameters of SC-CO2 extraction, including extraction pressure, temperature, time and CO2 flow rate on the yield of oak silkworm pupal oil (OSPO). The optimal extraction condition for oil yield within the experimental range of the variables researched was at 28.03 MPa, 1.83 h, 35.31 °C and 20.26 L/h as flow rate of CO2. Under this condition, the oil yield was predicted to be 26.18%. The oak silkworm pupal oil contains eight fatty acids, and is rich in unsaturated fatty acids and α-linolenic acid (ALA), accounting for 77.29% and 34.27% in the total oil respectively. PMID:22408458

Holocene Climate in Northwest Greenland Inferred from Oxygen Isotopes of Preserved Aquatic Organic Material

NASA Astrophysics Data System (ADS)

Lasher, G. E.; Axford, Y.; McFarlin, J. M.; Kelly, M. A.; Osterberg, E. C.; Farnsworth, L. B.; Kotecki, P.

2015-12-01

Oxygen isotopes of paleo lake-water archived in subfossil aquatic organic material offer new insights into Arctic Holocene climate history. Here we present new constraints on the timing and magnitude of Holocene climate change in NW Greenland inferred from δ18O of chironomid head capsules, Cladocera ephippia, and aquatic macrophytes. δ18O of chironomids from surface sediments of multiple lakes in the region show consistent enrichment relative to lake-water (-18 to -22 ‰), on the order of 23 ‰. Lake-water δ18O collected during the summer of 2014 is comparable to modern and historical seasonal local meteoric water, and landscape position suggests dominantly precipitation inputs. Sediment cores recovered from two small, non-glacial lakes in 2014 near Thule Air Base capture continuous 7.7 kyr and 10.4 kyr records. δ18O of chironomids and macrophytes from Secret Lake decreases after 6 ka by 3 ‰ into the Neoglacial. Early Holocene values from Wax Lips Lake (informal name) are 3 to 4 ‰ higher than modern and decrease to the present, except for a large negative excursion ~5 ka. This is contemporaneous with a major change in stratigraphy and the hypothesized transient incursion of a regional, ice-dammed glacial lake system. At both lakes, declining δ18O from the early/middle to late Holocene is clearly recorded in multiple aquatic materials and is greater in magnitude than the mid to late Holocene changes in δ18O of the nearest ice core records (Agassiz and Camp Century, ~2 ‰). The temperature change of 4 to 6 °C inferred from this new δ18O approach is also larger than, but within the error of, chironomid assemblage based temperatures from Wax Lips Lake by McFarlin et al. (this meeting). This may indicate larger temperature changes at the ice sheet's margin than inferred from high-elevation ice core sites and/or some overprinting by enhanced evaporation of lake-water in the warmer climate of the early Holocene.

Five Additional New Species of Uranotaenia from Southeast Asia (Diptera: Culicidae)

DTIC Science & Technology

1970-09-01

as holotype, C. Diraphat; 1 male, 2 females, 3 larval skins, 3 pupal skins ( CM133), Suan Mayao, Doi Sutep, Chiang Mai , THAILAND, 28 September 1963...SMRL; 3 females, 3 pupal skins, 3 larval skins, 4 larvae (05668), Doi Sutep, Chiang Mai , THAILAND, 10 December 1969, K. Mongkolpanya; 1 female...CM137), Huey Kheo, Doi Sutep, Chiang Mui, THAILAND, 1 October 1963, S. Esah; 2 larvae (05674)) Ban Tham, Chieng Dao, Chiang Mai , THAILAND, 11 December

Near Infrared Imaging As a Method of Studying Tsetse Fly (Diptera: Glossinidae) Pupal Development.

PubMed

Moran, Zelda R; Parker, Andrew G

2016-01-01

Near infrared (NIR) photography and video was investigated as a method for observing and recording intrapuparial development in the tsetse fly Glossina palpalis gambiensis and other Muscomorpha (Cyclorrhapha) Diptera. We showed that NIR light passes through the puparium, permitting images of the true pupae and pharate adult to be captured. Various wavelengths of NIR light from 880 to 1060 nm were compared to study the development of tsetse fly pupae from larviposition to emergence, using time-lapse videos and photographs. This study was carried out to advance our understanding of tsetse pupal development, specifically with the goal of improving a sorting technique which could separate male from female tsetse flies several days before emergence. Separation of the sexes at this stage is highly desirable for operational tsetse sterile insect technique control programmes, as it would permit the easy retention of females for the colony while allowing the males to be handled, irradiated and shipped in the pupal stage when they are less sensitive to vibration. In addition, it presents a new methodology for studying the pupal stage of many coarctate insects for many applications. NIR imaging permits observation of living pupae, allowing the entire development process to be observed without disruption. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America.

Zebra mussel effects on benthic invertebrates: physical or biotic?

USGS Publications Warehouse

Botts, P. Silver; Patterson, Benjamin A.; Schloesser, Don W.

1996-01-01

In soft sediments, Dreissena spp. create firm substrate in the form of aggregates of living mussels (druses) that roll free on the sediments. Druses provide physical structure which increases habitat heterogeneity, and the mussels increase benthic organic matter through the production of pseudofeces and feces. Descriptive and experimental studies were used to determine: 1) whether the density of benthic invertebrates in soft sediments increased in the presence of druses, and 2) whether the invertebrate assemblage responded to the physical structure provided by a druse or to some biotic effect associated with the presence of living mussels. In core samples collected biweekly during summer in Presque Isle Bay, Erie, Pennsylvania, amphipods, chironomids, oligochaetes, turbellarians, and hydrozoans were significantly more abundant in sand with druses than in bare sand. When mesh bags containing either a living druse, non-living druse, or no druse were incubated in the bay for 33 d, we found that chironomids were significantly more abundant in treatments with living druses than with non-living druses, and in treatments with non-living druses than with no druse; turbellarians, amphipods, and hydrozoans were significantly more abundant in treatments with living or non-living druses than with no druse; oligochaetes showed no significant differences among treatments. This study demonstrates that most taxa of benthic invertebrates in soft substrate respond specifically to the physical structure associated with aggregates of mussel shells, but further study is needed to examine chironomid responses to some biotic effect dependent on the presence of living mussels.

Evidence for early postglacial warming in Mount Field National Park, Tasmania

NASA Astrophysics Data System (ADS)

Rees, Andrew B. H.; Cwynar, Les C.

2010-02-01

Situated between the Western Pacific Warm Pool to the north and Antarctica to the south, Tasmania is an ideal location to study both postglacial and Holocene paleoclimates. Few well-dated, quantitative temperature reconstructions exist for the region so that important questions about the occurrence and magnitude of events, such as the Antarctic Cold Reversal and Younger Dryas, in Tasmania remain unanswered. Here, we provide chironomid-based reconstructions of temperature of the warmest quarter (TWARM) for two small subalpine lakes, Eagle and Platypus Tarns, Mount Field National Park. Shortly after deglaciation, TWARM reached modern values by approximately 15 000 cal a BP and remained high until 13 000 cal a BP after which temperatures began to cool steadily, reaching a minimum by 11 100-10 000 cal a BP. These results are consistent with sea surface temperature (SST) reconstructions from south of Tasmania but are in stark contrast to temperature inferences drawn from vegetation reconstructions based on pollen data that indicate cool initial temperatures followed by a broad warm period between 11 600-6800 cal a BP (10 000-6000 14C a BP). The chironomid record broadly matches the summer insolation curve whereas the vegetation record and associated climate inferences mirror winter insolation. The Antarctic Cold Reversal and Younger Dryas cold events are not evident in the chironomid-inferred temperatures, but the Antarctic Cold Reversal is evident in the loss-on-ignition curves.

People’s Republic of China Scientific Abstracts, Number 197

DTIC Science & Technology

1978-08-10

Chinese Academy of Sciences TITLE: "Characteristics of the DNA from Pupal Gonads of Bombyx Mori L.1*» SOURCE: Peking K’UN-CH’UNG HSUEH-PAO [ACTA...some fundamental properties of the DNA from the pupal gonada of Bombyx mori L. The results are as follows: The peak of u.v. absorption of the testicular...pest populations, especially by means of using their natural enemies and changing the spatial structures of their habitats ; (4) use of descrip

Insect acetyl-CoA carboxylase: activity during the larval, pupal and adult stages of insect development.

PubMed

Goldring, J P; Read, J S

1993-12-01

1. The activity of the lipogenic enzyme, acetyl-CoA carboxylase, was investigated in four insect species; Bombyx mori (Lepidoptera), Tenebrio molitor (Coleoptera), Glossina morsitans and Sarcophaga nodosa (Diptera). 2. Acetyl-CoA carboxylase activity in larval, pupal and adult forms was compared with the saponifiable lipid mass at each stage of the life-cycle, and found to follow similar patterns except for Tenebrio molitor. 3. The results are examined in relation to known metabolic requirements for each insect.

Additional Descriptions of Three Species of Culex (Eumelanomyia) with the Description of a New Species from Peninsular Malaysia (Diptera: Culicidae)

DTIC Science & Technology

1977-01-01

ded from Sabah. Material examined: 11 d, 5 9, 2 L; 2 individual rearings (1 pupal, 1 larval). MALAYSIA. Peninsukv Malaysia-Selangor: Kuala Langat ...swamp, from Tanjong Rabok, Kuala Langat Forest Reserve, Richard Garcia and John Jeffery, collectors. BIONOMICS. All specimens of sim@eieornis from...pupal and larval skins (Collection No. E9-713 and PR9-18) from Tan- jong Rabok, Kuala Langat , Forest Reserve, SeZangor, 19 July 1969, Ahmad Abdul Hamid

Effects of in situ climate warming on monarch caterpillar (Danaus plexippus) development.

PubMed

Lemoine, Nathan P; Capdevielle, Jillian N; Parker, John D

2015-01-01

Climate warming will fundamentally alter basic life history strategies of many ectothermic insects. In the lab, rising temperatures increase growth rates of lepidopteran larvae but also reduce final pupal mass and increase mortality. Using in situ field warming experiments on their natural host plants, we assessed the impact of climate warming on development of monarch (Danaus plexippus) larvae. Monarchs were reared on Asclepias tuberosa grown under 'Ambient' and 'Warmed' conditions. We quantified time to pupation, final pupal mass, and survivorship. Warming significantly decreased time to pupation, such that an increase of 1 °C corresponded to a 0.5 day decrease in pupation time. In contrast, survivorship and pupal mass were not affected by warming. Our results indicate that climate warming will speed the developmental rate of monarchs, influencing their ecological and evolutionary dynamics. However, the effects of climate warming on larval development in other monarch populations and at different times of year should be investigated.

Comparative efficacy of existing surveillance tools for Aedes aegypti in Western Kenya.

PubMed

Yalwala, Sancto; Clark, Jeffrey; Oullo, David; Ngonga, Daniel; Abuom, David; Wanja, Elizabeth; Bast, Joshua

2015-12-01

All traditional surveillance techniques for Aedes aegypti have been developed for the cosmopolitan domestic subspecies Ae. aegypti aegypti, and not the sylvatic subspecies, Ae. aegypti formosus. The predominant form in Western Kenya is Ae. aegypti formosus that is rarely associated with human habitations but is linked to transmission of sylvatic dengue virus strains. We compared five surveillance methods for their effectiveness in sampling Ae. aegypti formosus with the goal of determining a sustainable surveillance strategy in Kenya. The methods included larval and pupal surveys, oviposition trapping, BG-Sentinel trapping, resting boxes, and backpack aspirations. Larval and pupal surveys collected the highest number of Ae. aegypti formosus (51.3%), followed by oviposition traps (45.7%), BG-Sentinel traps (3.0%), and zero collected with either backpack aspiration or resting box collections. No Ae. aegypti formosus larvae or pupae were found indoors. The results indicate that oviposition traps and outdoor larval and pupal surveys were better surveillance methods for Ae. aegypti formosus in Western Kenya. © 2015 The Society for Vector Ecology.

Larval cannibalism and pupal defense against cannibalism in two species of tenebrionid beetles.

PubMed

Ichikawa, Toshio; Kurauchi, Toshiaki

2009-08-01

Cannibalism of pupae by larvae has been documented In many species of Insects, but the features of larval cannibalism and pupal defensive mechanisms against larval cannibalism have been largely Ignored. Pupae of tenebrionld beetles rotate their abdominal segments in a circular motion in response to the tactile stimulation of appendages, including legs, antennae, maxillary pulps, and wings. When the pupal abdominal rotation responses of Tenebrio molitor and Zophobas atratus were completely blocked by transecting the ventral nerve cord (VNC) of the pupae, the appendages of the paralytic pupae became initial, major targets for attack by larval cannibals. The majority of 20 paralytic pupae was cannibalized by 100 larvae within 6 h, and almost all the pupae were killed within 2-3 days. In contrast, only a few pupae of Z. atratus and several pupae of T. molitor were cannibalized when the VNC was Intact. The abdominal rotation response of the pupae thus functions as an effective defense against larval cannibalism.

Toxicity of cadmium and lead on tropical midge larvae, Chironomus kiiensis Tokunaga and Chironomus javanus Kieffer (Diptera: Chironomidae)

PubMed Central

Ebau, Warrin; Rawi, Che Salmah Md; Din, Zubir; Al-Shami, Salman Abdo

2012-01-01

Objective To investigate the acute toxicity of cadmium and lead on larvae of two tropical Chironomid species, Chironomus kiiensis (C. kiiensis) Tokunaga and Chironomus javanus (C. javanus) Kieffer. Methods Different larval instars (first-fourth) were exposed using a static non-replacement testing procedures to various concentrations of cadmium and lead. Results In general, younger larvae (first and second instars) of both species were more sensitive to both metals than older larvae (third and forth instars). The toxic effects of the metals on C. kiiensis and C. javanus were influenced by the age of the larvae (first to fourth instars), types of metals (cadmium or lead) and duration of larval exposure (24, 48, 72 and 96 h) to the metals. Conclusions Cadmium was more toxic to the chironomids than lead and C. javanus was significantly more sensitive to both metals than C. kiiensis (P<0.05). PMID:23569984

Control of chironamics in milkfish (Chanos chanos) ponds with Abate (Temephos) insecticide

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

Tsai, S.C.

Larval chironomids (Chironomus longilobus (Kieffer) are serious competitors with milkfish Chanos chanos (Forskal) for benthic algae in commercial milkfish ponds in Taiwan. Chironomid larvae were effectively killed with temephos (Abate, 0, 0, 0', 0'-tetramethyl 0, 0'-thiodi-p-phenylene phosphorothioate) 50% emulsifiable concentrate when it was diluted 1:2,000 with seawater and applied to milkfish ponds to establish a concentration of 0.050 mg/liter of the active ingredient. This treatment did not harm milkfish and benthic algae. Residues found in the edible portions of milkfish after seven applications of Abate 50% emulsifiable concentrate ranged from 0.02 to 0.08 mg/kg, well below the 1.0 mg/liter approvedmore » by the World Health Organization for presence in human drinking water. The acute toxicity of Abate 50% emulsifiable concentrate to 13 other species of aquatic animals was determined in the laboratory.« less

Induction of the cellular stress response in Chironomus (Diptera)

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

Pardalis, G.; Hudson, L.A.; Ciborowski, J.J.H.

1995-12-31

The accumulation of stress or heat shock proteins is involved in the protection and defense of a cell from environmentally induced damage. Under stressful conditions, cytoplasmic stress protein 70 migrates to the nucleus where it assists in the restoration of the nucleolar function. The authors have demonstrated a dose-response relationship between incidence of decreased nucleolar size in chironomid salivary glands and degree of sediment contamination. Reduced nucleolar size is indicative of reduced nucleolar function. The relationship between nucleolus size and stress protein accumulation is being explored. They are conducting experiments on chironomids to characterize the response elicited by heat shockmore » and PAH exposure in the laboratory to determine if the simultaneous action of more than one stressor can significantly alter the stress response. Simultaneous studies are being conducted to validate these biomarkers in mesocosm caging experiments. Aspects of the response will be useful as biomarkers of general stress.« less

Irrigation and fertilization effects on Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Damage levels and pupal weight in an intensively-managed pine plantation.

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

Coyle, David, R.; Nowak, John, T.; Fettig, Christopher, J.

2003-10-01

The widespread application of intensive forest management practices throughout the southeastern U.S. has increased loblolly pine, Pinus taeda L., yields and shortened conventional rotation lengths. Fluctuations in Nantucket pine tip moth, Rhyacionia frustrana (Comstock), population density and subsequent damage levels have been linked to variations in management intensity. We examined the effects of two practices, irrigation and fertilization, on R. frustrana damage levels and pupal weights in an intensively-managed P. taeda plantation in South Carolina. Trees received intensive weed control and one of the following treatments; irrigation only. fertilization only, irrigation + fertilization, or control. Mean whole-tree tip moth damagemore » levels ranged from <1 to 48% during this study. Damage levels differed significantly among treatments in two tip moth generations in 2001, but not 2000. Pupal weight was significantly heavier in fertilization compared to the irrigation treatment in 2000, but no significant differences were observed in 2001. Tree diameter. height. and aboveground volume were significantly greater in the irrigation + fertilization than in the irrigation treatment after two growing seasons. Our data suggest that intensive management practices that include irrigation and fertilization do not consistently increase R. frustrana damage levels and pupal weights as is commonly believed. However, tip moth suppression efforts in areas adjacent to our study may have partially reduced the potential impacts of R. frustrana on this experiment.« less

Pupal productivity & nutrient reserves of Aedes mosquitoes breeding in sewage drains & other habitats of Kolkata, India: Implications for habitat expansion & vector management.

PubMed

Banerjee, Soumyajit; Mohan, Sushree; Saha, Nabaneeta; Mohanty, Siba Prasad; Saha, Goutam K; Aditya, Gautam

2015-12-01

The quality of breeding sites is reflected through the pupal productivity and the life history traits of Aedes mosquitoes. Using nutrient reserves and pupal productivity of Aedes as indicators, the larval habitats including sewage drains were characterized to highlight the habitat expansion and vector management. The pupae and adults collected from the containers and sewage drains were characterized in terms of biomass and nutrient reserves and the data were subjected to three way factorial ANOVA. Discriminant function analyses were performed to highlight the differences among the habitats for sustenance of Aedes mosquitoes. Survey of larval habitats from the study area revealed significant differences (P<0.05) in the pupal productivity of Aedes among the habitats and months. Despite sewage drains being comparatively less utilized for breeding, the pupae were of higher biomass with corresponding adults having longer wings in contrast to other habitats. The nutrient reserve of the adults emerging from pupae of sewage drains was significantly higher (P<0.05), compared to other habitats, as reflected through the discriminant function analysis. The present results showed that for both Ae. aegypti and Ae. albopictus, sewage drains were equally congenial habitat as were plastic, porcelain and earthen habitats. Availability of Aedes immature in sewage drains poses increased risk of dengue, and thus vector control programme should consider inclusion of sewage drains as breeding habitat of dengue vector mosquitoes.

Molecular characterization of prophenoloxidase-1 (PPO1) and the inhibitory effect of kojic acid on phenoloxidase (PO) activity and on the development of Zeugodacus tau (Walker) (Diptera: Tephritidae).

PubMed

Zhang, H-H; Luo, M-J; Zhang, Q-W; Cai, P-M; Idrees, A; Ji, Q-E; Yang, J-Q; Chen, J-H

2018-06-22

Phenoloxidase (PO) plays a key role in melanin biosynthesis during insect development. Here, we isolated the 2310-bp full-length cDNA of PPO1 from Zeugodacus tau, a destructive horticultural pest. qRT-polymerase chain reaction showed that the ZtPPO1 transcripts were highly expressed during larval-prepupal transition and in the haemolymph. When the larvae were fed a 1.66% kojic acid (KA)-containing diet, the levels of the ZtPPO1 transcripts significantly increased by 2.79- and 3.39-fold in the whole larvae and cuticles, respectively, while the corresponding PO activity was significantly reduced; in addition, the larval and pupal durations were significantly prolonged; pupal weights were lowered; and abnormal phenotypes were observed. An in vitro inhibition experiment indicated that KA was an effective competitive inhibitor of PO in Z. tau. Additionally, the functional analysis showed that 20E could significantly up-regulate the expression of ZtPPO1, induce lower pupal weight, and advance pupation. Knockdown of the ZtPPO1 gene by RNAi significantly decreased mRNA levels after 24 h and led to low pupation rates and incomplete pupae with abnormal phenotypes during the larval-pupal interim period. These results proved that PO is important for the normal growth of Z. tau and that KA can disrupt the development of this pest insect.

Molecular identification and functional characterisation of uncoupling protein 4 in larva and pupa fat body mitochondria from the beetle Zophobas atratus.

PubMed

Slocinska, Malgorzata; Antos-Krzeminska, Nina; Rosinski, Grzegorz; Jarmuszkiewicz, Wieslawa

2012-08-01

Uncoupling protein 4 (UCP4) is a member of the UCP subfamily that mediates mitochondrial uncoupling, and sequence alignment predicts the existence of UCP4 in several insects. The present study demonstrates the first molecular identification of a partial Zophobas atratus UCP4-coding sequence and the functional characterisation of ZaUCP4 in the mitochondria of larval and pupal fat bodies of the beetle. ZaUCP4 shows a high similarity to predicted insect UCP4 isoforms and known mammalian UCP4s, both at the nucleotide and amino acid sequence levels. Bioenergetic studies clearly demonstrate UCP function in mitochondria from larval and pupal fat bodies. In non-phosphorylating mitochondria, ZaUCP activity was stimulated by palmitic acid and inhibited by the purine nucleotide GTP. In phosphorylating mitochondria, ZaUCP4 activity decreased the yield of oxidative phosphorylation. ZaUCP4 was immunodetected with antibodies raised against human UCP4 as a single 36-kDa band. A lower expression of ZaUCP4 at the level of mRNA and protein and a decreased ZaUCP4 activity were observed in the Z. atratus pupal fat body compared with the larval fat body. The different expression patterns and activity of ZaUCP4 during the larval-pupal transformation indicates an important physiological role for UCP4 in insect fat body development and function during insect metamorphosis. Copyright © 2012 Elsevier Inc. All rights reserved.

CELLULAR AND SECRETORY PROTEINS OF THE SALIVARY GLANDS OF SCIARA COPROPHILA DURING THE LARVAL-PUPAL TRANSFORMATION

PubMed Central

Been, Anita C.; Rasch, Ellen M.

1972-01-01

The cellular and secretory proteins of the salivary gland of Sciara coprophila during the stages of the larval-pupal transformation were examined by electrophoresis in 0.6 mm sheets of polyacrylamide gel with both SDS-continuous and discontinuous buffer systems. After SDS-electrophoresis, all electrophoretograms of both reduced and nonreduced proteins from single glands stained with Coomassie brilliant blue revealed a pattern containing the same 25 bands during the stages of the larval-pupal transformation. With the staining procedures used in this study, qualitative increases and decreases were detected in existing proteins and enzymes. There was no evidence, however, for the appearance of new protein species that could be correlated with the onset of either pupation or gland histolysis. Electrophoretograms of reduced samples of anterior versus posterior gland parts indicated that no protein in the basic pattern of 25 bands was unique to either the anterior or posterior gland part. Electrophoretograms of reduced samples of secretion collected from either actively feeding or "cocoon"-building animals showed an electrophoretic pattern containing up to six of the 25 protein fractions detected in salivary gland samples, with varied amounts of these same six proteins in electrophoretograms of secretion samples from a given stage. Zymograms of non-specific esterases in salivary gland samples revealed a progressive increase in the amount of esterase reaction produce in one major band and some decrease in the second major band during later stages of the larval-pupal transformation. PMID:4116523

Effects of mining activities on heavy metal concentrations in water, sediment, and macroinvertebrates in different reaches of the Pilcomayo River, South America.

PubMed

Smolders, A J P; Lock, R A C; Van der Velde, G; Medina Hoyos, R I; Roelofs, J G M

2003-04-01

From 1997 until 1999 the extent and the ecological effects of zinc, copper, lead, and cadmium pollution were studied in different reaches of the South American Pilcomayo River. A comparison of metal concentrations in water, sediment, and chironomid larvae, as well as the diversity of macroinvertebrate species, was made between sites near the origin of the Pilcomayo River, with hardly any mining activities, sites in the Potosí region, with intensive mining, and sites located 500 km or further downstream of Potosí, in the Chaco plain. Samples were also collected in an unpolluted river (Cachi Mayu River) and in the Tarapaya River, which is strongly contaminated by mine tailings (1000 tons a day). The upper parts of the Pilcomayo River are strongly affected by the release of mine tailings from the Potosí mines where mean concentrations of lead, cadmium, copper, and zinc in water, filtered water, sediment, and chironomid larvae were up to a thousand times higher than the local background levels. The diversity of the benthic macroinvertebrate community was strongly reduced in the contaminated parts; 97% of the benthic macroinvertebrates consisted of chironomid larvae. The degree of contamination in the lower reaches of the river, however, was fairly low because of sedimentation processes and the strong dilution of mine tailings with enormous amounts of clean sediment from erosion processes. Analysis of sediment cores from the Ibibobo floodplain, however, reveal an increase of the heavy metal concentrations in the lower reaches since the introduction of the contaminating flotation process in the mine industry in 1985.

Feeding ecology of Gila boraxobius (Osteichthyes: Cyprindae) endemic to a thermal lake in southeastern Oregon

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

Williams, J.E.; Williams, C.D.

1980-06-30

Gila boraxobius is a dwarf species of cyprinid endemic to a thermal lake in southeastern Oregon. Despite a relatively depauperate fauna and flora in the lake, 24 food items were found in intestines of G. boraxobius. Ten of the 24 foods, including six insects, were of terrestrial origin. The relative importance of food items fluctuated seasonally. Diatoms, chironomid larvae, microcrustaceans, and dipteran adults were the primary foods during spring. In summer, diatoms decreased and terrestrial insects increased in importance. During autumn important foods were terrestrial insects, chironomid larvae, and diatoms. Diatoms and microcrustaceans increased in importance during winter. Chironomid larvaemore » were of importance in winter, when the importance of terrestrial food items decreased substantially. Similar food habits were observed between juveniles and adults, except that adults consumed more gastropods and diatoms and juveniles consumed more copepods and terrestrial insects. Gila boraxobius feeds opportunistically with individuals commonly containing mostly one food item. Fish typically feed by picking foods from soft bottom sediments or from rocks. However, fish will feed throughout the water column or on the surface if food is abundant there. Gila boraxobius feeds throughout the day, with a peak in feeding activity just after sunset. A daily ration of 11.1 percent body weight was calculated for the species during June. A comparison of food habits among G. boraxobius and populations of G. alvordensis during the summer shows that all are opportunistic in feeding, but that G. boraxobius relies more heavily on terrestrial foods.« less

Distribution of polychlorinated biphenyls in an urban riparian zone affected by wastewater treatment plant effluent and the transfer to terrestrial compartment by invertebrates.

PubMed

Yu, Junchao; Wang, Thanh; Han, Shanlong; Wang, Pu; Zhang, Qinghua; Jiang, Guibin

2013-10-01

In this study, we investigated the distribution of polychlorinated biphenyls (PCBs) in a riparian zone affected by the effluent from a wastewater treatment plant (WWTP). River water, sediment, aquatic invertebrates and samples from the surrounding terrestrial compartment such as soil, reed plants and several land based invertebrates were collected. A relatively narrow range of δ(13)C values was found among most invertebrates (except butterflies, grasshoppers), indicating a similar energy source. The highest concentration of total PCBs was observed in zooplankton (151.1 ng/g lipid weight), and soil dwelling invertebrates showed higher concentrations than phytophagous insects at the riparian zone. The endobenthic oligochaete Tubifex tubifex (54.28 ng/g lw) might be a useful bioindicator of WWTP derived PCBs contamination. High bioaccumulation factors (BAFs) were observed in collected aquatic invertebrates, although the biota-sediment/soil accumulation factors (BSAF) remained relatively low. Emerging aquatic insects such as chironomids could carry waterborne PCBs to the terrestrial compartment via their lifecycles. The estimated annual flux of PCBs for chironomids ranged from 0.66 to 265 ng⋅m(-2)⋅y(-1). Although a high prevalence of PCB-11 and PCB-28 was found for most aquatic based samples in this riparian zone, the mid-chlorinated congeners (e.g. PCB-153 and PCB-138) became predominant among chironomids and dragonflies as well as soil dwelling invertebrates, which might suggest a selective biodriven transfer of different PCB congeners. Copyright © 2013 Elsevier B.V. All rights reserved.

Draft Test Guideline: Chironomid Sediment Toxicity Test

EPA Pesticide Factsheets

The following draft test guideline is part of a series of test guidelines that have been developed by EPA for use in the testing of pesticides and toxic substances, and the development of test data for submission to the Agency for review.

20-Hydroxyecdysone (20E) Primary Response Gene E93 Modulates 20E Signaling to Promote Bombyx Larval-Pupal Metamorphosis*

PubMed Central

Liu, Xi; Dai, Fangyin; Guo, Enen; Li, Kang; Ma, Li; Tian, Ling; Cao, Yang; Zhang, Guozheng; Palli, Subba R.; Li, Sheng

2015-01-01

As revealed in a previous microarray study to identify genes regulated by 20-hydroxyecdysone (20E) and juvenile hormone (JH) in the silkworm, Bombyx mori, E93 expression in the fat body was markedly low prior to the wandering stage but abundant during larval-pupal metamorphosis. Induced by 20E and suppressed by JH, E93 expression follows this developmental profile in multiple silkworm alleles. The reduction of E93 expression by RNAi disrupted 20E signaling and the 20E-induced autophagy, caspase activity, and cell dissociation in the fat body. Reducing E93 expression also decreased the expression of the 20E-induced pupal-specific cuticle protein genes and prevented growth and differentiation of the wing discs. Importantly, the two HTH domains in E93 are critical for inducing the expression of a subset of 20E response genes, including EcR, USP, E74, Br-C, and Atg1. By contrast, the LLQHLL and PLDLSAK motifs in E93 inhibit its transcriptional activity. E93 binds to the EcR-USP complex via a physical association with USP through its LLQHLL motif; and this association is enhanced by 20E-induced EcR-USP interaction, which attenuates the transcriptional activity of E93. E93 acts through the two HTH domains to bind to GAGA-containing motifs present in the Atg1 promoter region for inducing gene expression. In conclusion, E93 transcriptionally modulates 20E signaling to promote Bombyx larval-pupal metamorphosis. PMID:26378227

20-Hydroxyecdysone (20E) Primary Response Gene E93 Modulates 20E Signaling to Promote Bombyx Larval-Pupal Metamorphosis.

PubMed

Liu, Xi; Dai, Fangyin; Guo, Enen; Li, Kang; Ma, Li; Tian, Ling; Cao, Yang; Zhang, Guozheng; Palli, Subba R; Li, Sheng

2015-11-06

As revealed in a previous microarray study to identify genes regulated by 20-hydroxyecdysone (20E) and juvenile hormone (JH) in the silkworm, Bombyx mori, E93 expression in the fat body was markedly low prior to the wandering stage but abundant during larval-pupal metamorphosis. Induced by 20E and suppressed by JH, E93 expression follows this developmental profile in multiple silkworm alleles. The reduction of E93 expression by RNAi disrupted 20E signaling and the 20E-induced autophagy, caspase activity, and cell dissociation in the fat body. Reducing E93 expression also decreased the expression of the 20E-induced pupal-specific cuticle protein genes and prevented growth and differentiation of the wing discs. Importantly, the two HTH domains in E93 are critical for inducing the expression of a subset of 20E response genes, including EcR, USP, E74, Br-C, and Atg1. By contrast, the LLQHLL and PLDLSAK motifs in E93 inhibit its transcriptional activity. E93 binds to the EcR-USP complex via a physical association with USP through its LLQHLL motif; and this association is enhanced by 20E-induced EcR-USP interaction, which attenuates the transcriptional activity of E93. E93 acts through the two HTH domains to bind to GAGA-containing motifs present in the Atg1 promoter region for inducing gene expression. In conclusion, E93 transcriptionally modulates 20E signaling to promote Bombyx larval-pupal metamorphosis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Phenoloxidase activity among developmental stages and pupal cell types of the ground beetle Carabus (Chaetocarabus) lefebvrei (Coleoptera, Carabidae).

PubMed

Giglio, Anita; Giulianini, Piero Giulio

2013-04-01

In ecological immunology is of great importance the study of the immune defense plasticity as response to a variable environment. In holometabolous insects the fitness of each developmental stage depends on the capacity to mount a response (i.e. physiological, behavioral) under environmental pressure. The immune response is a highly dynamic trait closely related to the ecology of organism and the variation in the expression of an immune system component may affect another fitness relevant trait of organism (i.e. growth, reproduction). The present research quantified immune function (total and differential number of hemocytes, phagocytosis in vivo and activity of phenoloxidase) in the pupal stage of Carabus (Chaetocarabus) lefebvrei. Moreover, the cellular and humoral immune function was compared across the larval, pupal and adult stages to evaluate the changes in immunocompetence across the developmental stages. Four types of circulating hemocytes were characterized via transmission electron microscopy in the pupal stage: prohemocytes, plasmatocytes, granulocytes and oenocytoids. The artificial non-self-challenge treatments performed in vivo have shown that plasmatocytes and granulocytes are responsible for phagocytosis. The level of active phenoloxidase increases with the degree of pigmentation of the cuticle in each stage. In C. lefebvrei, there are different strategies in term of immune response to enhance the fitness of each life stage. The results have shown that the variation in speed and specificity of immune function across the developmental stages is correlated with differences in infection risk, life expectancy and biological function of the life cycle. Copyright © 2013 Elsevier Ltd. All rights reserved.

Patterns of Aedes aegypti (Diptera: Culicidae) Infestation and Container Productivity Measured Using Pupal and Stegomyia Indices in Northern Argentina

PubMed Central

Garelli, F. M.; Espinosa, M. O.; Weinberg, D.; Coto, H. D.; Gaspe, M. S.; Gürtler, R. E.

2011-01-01

A citywide control program of Aedes aegypti (L.) (Diptera: Culicidae) mainly based on the use of larvicides reduced infestations but failed to achieve the desired target levels in Clorinda, northeastern Argentina, over 5 yr of interventions. To understand the underlying causes of persistent infestations and to develop new control tactics adapted to the local context, we conducted two pupal surveys in a large neighborhood with ≈2,500 houses and recorded several variables for every container inspected in fall and spring 2007. In total, 4,076 lots and 4,267 containers were inspected over both surveys, and 8,391 Ae. aegypti pupae were collected. Large tanks used for potable water storage were the most abundant and the most productive type of container, accounting for 65–84% of all the pupae collected. Therefore, large tanks were key containers and candidates for improved targeted interventions. Multivariate analysis showed that containers located in the yard, at low sun exposure, unlidded, filled with rain water, and holding polluted water were all more likely to be infested by larvae or pupae. When only infested containers were considered, productivity of pupae was most closely associated with large tanks and rain water. A stochastic simulation model was developed to calculate the expected correlations between pupal and Stegomyia indices according to the characteristics of the distribution of larvae and pupae per container and the spatial scale at which the indices were computed. The correlation between pupal and Stegomyia indices is expected to increase as infestation levels decline. PMID:19769052

Milkweed Matters: Monarch Butterfly (Lepidoptera: Nymphalidae) Survival and Development on Nine Midwestern Milkweed Species

PubMed Central

Pocius, V M; Debinski, D M; Pleasants, J M; Bidne, K G; Hellmich, R L; Brower, L P

2017-01-01

Abstract The population of monarch butterflies east of the Rocky Mountains has experienced a significant decline over the past 20 yr. In order to increase monarch numbers in the breeding range, habitat restoration that includes planting milkweed plants is essential. Milkweeds in the genus Asclepias and Cynanchum are the only host plants for larval monarch butterflies in North America, but larval performance and survival across nine milkweeds native to the Midwest is not well documented. We examined development and survival of monarchs from first-instar larval stages to adulthood on nine milkweed species native to Iowa. The milkweeds included Asclepias exaltata (poke milkweed) (Gentianales: Apocynaceae), Asclepias hirtella (tall green milkweed) (Gentianales: Apocynaceae), Asclepias incarnata (swamp milkweed) (Gentianales: Apocynaceae), Asclepias speciosa (showy milkweed) (Gentianales: Apocynaceae), Asclepias sullivantii (prairie milkweed) (Gentianales: Apocynaceae), Asclepias syriaca (common milkweed) (Gentianales: Apocynaceae), Asclepias tuberosa (butterfly milkweed) (Gentianales: Apocynaceae), Asclepias verticillata (whorled milkweed) (Gentianales: Apocynaceae), and Cynanchum laeve (honey vine milkweed) (Gentianales: Apocynaceae). In greenhouse experiments, fewer larvae that fed on Asclepias hirtella and Asclepias sullivantii reached adulthood compared with larvae that fed on the other milkweed species. Monarch pupal width and adult dry mass differed among milkweeds, but larval duration (days), pupal duration (days), pupal mass, pupal length, and adult wet mass were not significantly different. Both the absolute and relative adult lipids were different among milkweed treatments; these differences are not fully explained by differences in adult dry mass. Monarch butterflies can survive on all nine milkweed species, but the expected survival probability varied from 30 to 75% among the nine milkweed species. PMID:28961914

Mating competitiveness of male Anopheles arabiensis mosquitoes irradiated with a partially or fully sterilizing dose in small and large laboratory cages.

PubMed

Helinski, M E H; Knols, B G J

2008-07-01

Male mating competitiveness is a crucial parameter in many genetic control programs including the sterile insect technique (SIT). We evaluated competitiveness of male Anopheles arabiensis Patton as a function of three experimental variables: (1) small or large cages for mating, (2) the effects of either a partially sterilizing (70 Gy) or fully sterilizing (120 Gy) dose, and (3) pupal or adult irradiation. Irradiated males competed for females with an equal number of unirradiated males. Competitiveness was determined by measuring hatch rates of individually laid egg batches. In small cages, pupal irradiation with the high dose resulted in the lowest competitiveness, whereas adult irradiation with the low dose gave the highest, with the latter males being equal in competitiveness to unirradiated males. In the large cage, reduced competitiveness of males irradiated in the pupal stage was more pronounced compared with the small cage; the males irradiated as adults at both doses performed similarly to unirradiated males. Unexpectedly, males irradiated with the high dose performed better in a large cage than in a small one. A high proportion of intermediate hatch rates was observed for eggs collected in the large cage experiments with males irradiated at the pupal stage. It is concluded that irradiation of adult An. arabiensis with the partially sterilizing dose results in the highest competitiveness for both cage designs. Cage size affected competitiveness for some treatments; therefore, competitiveness determined in laboratory experiments must be confirmed by releases into simulated field conditions. The protocols described are readily transferable to evaluate male competitiveness for other genetic control techniques.

Natural variability in Drosophila larval and pupal NaCl tolerance.

PubMed

Riedl, Craig A L; Oster, Sara; Busto, Macarena; Mackay, Trudy F C; Sokolowski, Marla B

2016-05-01

The regulation of NaCl is essential for the maintenance of cellular tonicity and functionality, and excessive salt exposure has many adverse effects. The fruit fly, Drosophila melanogaster, is a good osmoregulator and some strains can survive on media with very low or high NaCl content. Previous analyses of mutant alleles have implicated various stress signaling cascades in NaCl sensitivity or tolerance; however, the genes influencing natural variability of NaCl tolerance remain for the most part unknown. Here, we use two approaches to investigate natural variation in D. melanogaster NaCl tolerance. We describe four D. melanogaster lines that were selected for different degrees of NaCl tolerance, and present data on their survival, development, and pupation position when raised on varying NaCl concentrations. After finding evidence for natural variation in salt tolerance, we present the results of Quantitative Trait Loci (QTL) mapping of natural variation in larval and pupal NaCl tolerance, and identify different genomic regions associated with NaCl tolerance during larval and pupal development. Copyright © 2016 Elsevier Ltd. All rights reserved.

Magnetic Resonance Imaging of Alimentary Tract Development in Manduca sexta

PubMed Central

Rowland, Ian J.; Goodman, Walter G.

2016-01-01

Non-invasive 3D magnetic resonance imaging techniques were used to investigate metamorphosis of the alimentary tract of Manduca sexta from the larval to the adult stage. The larval midgut contracts in volume immediately following cessation of feeding and then greatly enlarges during the late pharate pupal period. Magnetic resonance imaging revealed that the foregut and hindgut of the pharate pupa undergo ecdysis considerably earlier than the external exoskeleton. Expansion of air sacs in the early pupa and development of flight muscles several days later appear to orient the midgut into its adult position in the abdomen. The crop, an adult auxiliary storage organ, begins development as a dorsal outgrowth of the foregut. This coincides with a reported increase in pupal ecdysteroid titers. An outgrowth of the hindgut, the rectal sac, appears several days later and continues to expand until it nearly fills the dorsal half of the abdominal cavity. This development correlates with a second rise in pupal ecdysteroid titers. In the pharate pupa, the presence of paramagnetic species renders the silk glands hyperintense. PMID:27280776

Reed beds may facilitate transfer of tributyltin from aquatic to terrestrial ecosystems through insect vectors in the Archipelago Sea, SW Finland.

PubMed

Lilley, Thomas M; Meierjohann, Axel; Ruokolainen, Lasse; Peltonen, Jani; Vesterinen, Eero; Kronberg, Leif; Nikinmaa, Mikko

2012-08-01

Due to their adsorptive behavior, organotin compounds (OTCs), such as tributyltin (TBT), are accumulated in aquatic sediments. They resist biodegradation and, despite a ban in 2008, are a potential source for future exposure. Sediment OTCs have mostly been measured from sites of known high concentrations such as ports, shipping lanes, and marine dredging waste sites. The possible flow of OTCs from marine to terrestrial ecosystems, however, has not been studied. In the present study, the authors assessed whether sediments in common reed beds (Phragmites australis) accumulate TBT and whether chironomid (Diptera: Chironomidae) communities developing in reed-bed sediments act as vectors in the transfer of TBT from aquatic to terrestrial ecosystems in the Airisto channel, Archipelago Sea. The authors also investigated whether distance from the only known source and depth and TBT concentration of the adjacent shipping lane affect reed-bed concentrations. Thirty-six sites along the Airisto channel were sampled at 2-km intervals with triplicate samples from reed beds and the adjacent shipping lane for sediment and seven reed-bed sites for chironomids, and these were analyzed with an solid phase extraction liquid chromatography tamdem mass spectrometry method. The closer to the source the sample site was, the higher the measured TBT concentrations were; and the deeper the shipping lane, the lower the concentration of TBT in reed-bed sediments. The chironomid TBT concentrations correlated with reed-bed sediment TBT concentrations and showed evidence of accumulation. Therefore, TBT may be transferred, through the food web, from aquatic to terrestrial ecosystems relatively close to a source through ecosystem boundaries, such as common reed beds, which are areas of high insect biomass production in the Archipelago Sea. Copyright © 2012 SETAC.

Chironomid oxygen isotope record of mid- to late Holocene climate evolution from southern Spitsbergen

NASA Astrophysics Data System (ADS)

Arppe, Laura; Kurki, Eija; Wooller, Matthew; Luoto, Tomi; Zajączkowski, Marek; Ojala, Antti

2017-04-01

The oxygen isotope composition of head capsule chitin of chironomid larvae picked from a sediment core covering the past 5500 years from lake Svartvatnet in southern Spitsbergen was used to reconstruct the isotopic composition of oxygen in lake water (δ18Olw) and local precipitation. Consistent with the gradual cooling of climate over the Neoglacial period, the δ18Olw record displays a gentle decreasing trend over the study period. The Svartvatnet δ18Olwrecord shows a maximum at ca. 1900-1800 cal BP, consistent with the timing of the Roman Warm Period, and three negative excursions increasing in intensity towards the present-day at 3400-3200, 1250-1100 and 350-50 cal BP, which are tentatively linked to multidecadal periods of low solar activity amplified by oceanic and atmospheric feedbacks. The time period of the Little Ice Age shows a two-step decrease in δ18Olwvalues, with a remarkable, 8-9‰ drop at 350-50 cal BP construed to predominantly represent significantly decreased winter temperatures during a period of increased seasonal differences and extended sea ice cover inducing changes in moisture source regions. Similarity of the trends between the δ18Olwrecord and a July-T reconstruction based on chironomid assemblages (Luoto et al., in review) from the same core suggests that air temperature exerts a significant control over the δ18Olwvalues, but the record is most likely influenced by changes in sea ice extent and possibly the seasonal distribution of precipitation. Reference: Luoto TP, Ojala A, Brooks S et al. Synchronized proxy-based temperature reconstructions reveal mid-to late Holocene climate oscillations in High Arctic Svalbard. Journal of Quaternary Science, submitted.

Two faces of agricultural intensification hanging over aquatic biodiversity: The case of chironomid diversity from farm ponds vs. natural wetlands in a coastal region

NASA Astrophysics Data System (ADS)

Fenoy, Encarnación; Casas, J. Jesús

2015-05-01

Increasing agricultural land use and intensification have given rise to the loss and eutrophication of coastal wetlands worldwide. In Mediterranean coastal regions, irrigated agriculture, in turn, has prompted the proliferation of farm ponds which might compensate for wetland loss and degradation if their management regimen results are compatible with biodiversity conservation. Here, we studied regional (γ-), local (α-) and interlocal (β-) diversities of chironomids in coastal wetlands and irrigation ponds from a Mediterranean region, to determine the contribution of each habitat type to regional diversity, and to disentangle which environmental factors, anthropogenic or natural, contributed most to explain diversity patterns. Regional diversity was slightly, but still significantly, higher in natural wetlands than in farm ponds, which can be attributed to the significantly higher β-diversity in natural wetlands, since, despite the much larger surface area of wetlands, both habitat types did not differ in local diversity (α-diversity). In both habitats, however, the contribution of β-diversity to regional diversity was higher compared to that of α-diversity, and the component 'spatial species turnover' exceeded that of the component 'nestedness' of β-diversity. This, together with an outstanding assemblage complementarity (approx. 50%) between habitat types, emphasizes the vital contribution of farm ponds, together with natural wetlands, to regional diversity. Despite the higher salinity and eutrophication of natural wetlands that tended to reduce diversity in chironomid assemblages, their more heterogeneous shore line likely compensated somewhat for such negative effects. Unlike wetlands, the homogeneous and unvegetated shore of farm ponds, in conjunction with their intensive management, probably induced adverse effects on local and interlocal diversity. Specific recommendations are given in this regards to mitigate impacts and improve the value of both habitats for biodiversity conservation.

Riethia manauara n. sp., an Amazonian Chironomid (Diptera: Chironomidae) from Brazil.

PubMed

Neubern, C S O; Trivinho-Strixino, S; da Silva, Fabio L

2011-10-01

One new species of Riethia Kieffer, Riethia manauara n. sp., is described and figured as male, pupa and larva. The generic diagnosis for pupae and larvae are emended. The specimens were collected from water systems in the Amazon Rainforest in northern Brazil.

Spider-mediated flux of PCBs from contaminated sediments to terrestrial ecosystems and potential risks to arachnivorous birds

EPA Science Inventory

We investigated aquatic insect utilization and PCB exposure in riparian spiders at the Lake Hartwell superfund site (Clemson, SC , USA). We sampled sediments, adult chironomids, terrestrial insects, riparian spiders (Tetragnathidae, Araneidae, and Mecynogea lemniscata), and upla...

Molecular mechanism underlying juvenile hormone-mediated repression of precocious larval-adult metamorphosis.

PubMed

Kayukawa, Takumi; Jouraku, Akiya; Ito, Yuka; Shinoda, Tetsuro

2017-01-31

Juvenile hormone (JH) represses precocious metamorphosis of larval to pupal and adult transitions in holometabolous insects. The early JH-inducible gene Krüppel homolog 1 (Kr-h1) plays a key role in the repression of metamorphosis as a mediator of JH action. Previous studies demonstrated that Kr-h1 inhibits precocious larval-pupal transition in immature larva via direct transcriptional repression of the pupal specifier Broad-Complex (BR-C). JH was recently reported to repress the adult specifier gene Ecdysone-induced protein 93F (E93); however, its mechanism of action remains unclear. Here, we found that JH suppressed ecdysone-inducible E93 expression in the epidermis of the silkworm Bombyx mori and in a B. mori cell line. Reporter assays in the cell line revealed that the JH-dependent suppression was mediated by Kr-h1. Genome-wide ChIP-seq analysis identified a consensus Kr-h1 binding site (KBS, 14 bp) located in the E93 promoter region, and EMSA confirmed that Kr-h1 directly binds to the KBS. Moreover, we identified a C-terminal conserved domain in Kr-h1 essential for the transcriptional repression of E93 Based on these results, we propose a mechanism in which JH-inducible Kr-h1 directly binds to the KBS site upstream of the E93 locus to repress its transcription in a cell-autonomous manner, thereby preventing larva from bypassing the pupal stage and progressing to precocious adult development. These findings help to elucidate the molecular mechanisms regulating the metamorphic genetic network, including the functional significance of Kr-h1, BR-C, and E93 in holometabolous insect metamorphosis.

Observations on the Biology of Afrotropical Hesperiidae (Lepidoptera). Part 5. Hesperiinae incertae sedis: Dicotyledon Feeders.

PubMed

Cock, Matthew J; Congdon, T Colin E

2013-01-01

Partial life histories of 24 Hesperiinae incertae sedis that feed on Dicotyledons are described and illustrated. The genera dealt with are: Acada, Acleros, Andronymus, Fresna, Gorgyra, Melphinyet, Meza, Paronymus, Parosmodes, Platylesches, and Teniorhinus. The food plants of Gorgyra (mainly Connaraceae), Melphinyet (Euphorbiaceae) and Platylesches (Chrysobalanaceae) stand out as clearly distinct from those of the other six genera, which share one or two food plant fam-ilies with each other. Thus four genera include Fabaceae in their food plants, two include Sapindaceae, two include Com-bretaceae, and Andronymus includes all three. Ova are only reported for five genera, but they do point to some significant differences: Gorgyra, Parosmodes and Platylesches are different from each other, and different from Acleros and Andro-nymus. The features of the caterpillars do not indicate clear patterns. The pupal shelters point to Parosmodes and Mel-phinyet showing some affinity and certainly differ from all others. Acleros and Andronymus have similar pupal shelters, and in common with Meza (dicotyledon-feeding species) and Fresna, the pupal chamber is not closed and the pupa rests on the leaf upper surface. The pupae of Gorgyra differ from all others. The pupae of Acleros and Andronymus have their colouring in common, probably reflecting their very similar pupal shelters. Similarly the pupae and shelters of Meza (di-cotyledon-feeding species) and Fresna seem analogous. The other pupae, hidden in their shelters are less differentiated, although the completely wax-free shelter of Acada is superficially different. We conclude that the likeliest scenario is that in the Afrotropical Region members of the Hesperiinae incertae sedis have made the switch from monocotyledons to di-cotyledons several times, and then radiated.

Efficacy of indigenous entomopathogenic nematodes (Rhabditida: Heterorhabditidae, Steinernematidae), from Rio Grande do Sul Brazil, against Anastrephafraterculus (Wied.) (Diptera: Tephritidae) in peach orchards.

PubMed

Barbosa-Negrisoli, Carla R C; Garcia, Mauro S; Dolinski, Claudia; Negrisoli, Aldomario S; Bernardi, Daniel; Nava, Dori Edson

2009-09-01

Laboratory, greenhouse, and field experiments were performed with the objective of selecting efficient indigenous strains of entomopathogenic nematodes (EPNs) from Rio Grande do Sul (RS) state, Brazil, for controlling the South American fruit fly, Anastrepha fraterculus (Wied.). Laboratory experiments were conducted in 24 well-plates filled with sterile sand and one insect per well. In greenhouse experiments, plastic trays filled with soil collected from the field were used, while in field experiments, holes were made in soil under the edge of peach tree canopies. Among 19 EPN strains tested, Heterorhabditis bacteriophora Poinar RS88 and Steinernema riobrave Cabanillas, Poinar, & Raulston RS59 resulted in higher A. fraterculus larval (pre-pupal) and pupal mortality, with LD(90) of 1630, 457 and 2851, 423 infective juveniles (IJs)/cm(2), respectively. Greenhouse experiments showed no differences in pupal mortality at 250 and 500IJs/cm(2) of either nematode. In the field, H. bacteriophora RS88 and S. riobravae RS59 sprayed individually over natural and artificially infested fruit (250IJs/cm(2)) resulted in A. fraterculus larval mortality of 51.3%, 28.1% and 20%, 24.3%, respectively. There was no significant difference in A. fraterculus pupal mortality sprayed with an aqueous suspension of either nematode; however, when using infected insect cadavers, H. bacteriophora RS88 was more efficient than S. riobrave RS59. Our results showed that H. bacteriophora RS88 was more virulent to insect larvae, with an efficient host search inside the infested fruit and control of pupae in the soil after being applied by aqueous suspension or infected cadavers.

Milkweed Matters: Monarch Butterfly (Lepidoptera: Nymphalidae) Survival and Development on Nine Midwestern Milkweed Species.

PubMed

Pocius, V M; Debinski, D M; Pleasants, J M; Bidne, K G; Hellmich, R L; Brower, L P

2017-10-01

The population of monarch butterflies east of the Rocky Mountains has experienced a significant decline over the past 20 yr. In order to increase monarch numbers in the breeding range, habitat restoration that includes planting milkweed plants is essential. Milkweeds in the genus Asclepias and Cynanchum are the only host plants for larval monarch butterflies in North America, but larval performance and survival across nine milkweeds native to the Midwest is not well documented. We examined development and survival of monarchs from first-instar larval stages to adulthood on nine milkweed species native to Iowa. The milkweeds included Asclepias exaltata (poke milkweed) (Gentianales: Apocynaceae), Asclepias hirtella (tall green milkweed) (Gentianales: Apocynaceae), Asclepias incarnata (swamp milkweed) (Gentianales: Apocynaceae), Asclepias speciosa (showy milkweed) (Gentianales: Apocynaceae), Asclepias sullivantii (prairie milkweed) (Gentianales: Apocynaceae), Asclepias syriaca (common milkweed) (Gentianales: Apocynaceae), Asclepias tuberosa (butterfly milkweed) (Gentianales: Apocynaceae), Asclepias verticillata (whorled milkweed) (Gentianales: Apocynaceae), and Cynanchum laeve (honey vine milkweed) (Gentianales: Apocynaceae). In greenhouse experiments, fewer larvae that fed on Asclepias hirtella and Asclepias sullivantii reached adulthood compared with larvae that fed on the other milkweed species. Monarch pupal width and adult dry mass differed among milkweeds, but larval duration (days), pupal duration (days), pupal mass, pupal length, and adult wet mass were not significantly different. Both the absolute and relative adult lipids were different among milkweed treatments; these differences are not fully explained by differences in adult dry mass. Monarch butterflies can survive on all nine milkweed species, but the expected survival probability varied from 30 to 75% among the nine milkweed species. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America.

Pupal-productivity surveys to identify the key container habitats of Aedes aegypti (L.) in Barranquilla, the principal seaport of Colombia.

PubMed

Romero-Vivas, C M E; Arango-Padilla, P; Falconar, A K I

2006-04-01

Surveys were conducted in three neighbourhoods of Barranquilla, the main seaport of Colombia, to identify, using counts of pupae in water containers during the wet and dry seasons, the most productive Aedes aegypti breeding sites. Overall, 3,433 premises were investigated in the wet season and 3,563 in the dry, representing, respectively, 82.3% and 84.6% of the total numbers of premises in the study areas. Despite a reasonably reliable supply of piped water, there were still some large storage containers for domestic water (cement ground tanks and plastic, metal and cement drums) in the area. Although such containers represented only 1.8%-16.3% of the total number of containers observed, they contributed 72.0%-78.2% and 65.0%-95.8% of the total Ae. aegypti pupal population in the three study neighbourhoods during the wet and dry seasons, respectively. In contrast, bottles represented 23.0%-88.9% of the total number of containers but produced no more than 0.1% of the total Ae aegypti pupal populations in these neighbourhoods. Other containers (tyres, vases, 'other discarded' and 'other used') generally produced only low numbers of pupae. In some settings, however, containers in the 'other discarded' category could contribute up to 19% of the total pupal population, and in one survey of one neighbourhood a single container in this category held 9.1% of all the pupae collected. These results, from a city where dengue fever is endemic, will help to focus local campaigns for Ae. aegypti source-reduction on the most productive categories of container.

Genetic link between Cabeza, a Drosophila homologue of Fused in Sarcoma (FUS), and the EGFR signaling pathway

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

Shimamura, Mai; Kyotani, Akane; Insect Biomedical Research Center, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585

2014-08-01

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease that causes progressive muscular weakness. Fused in Sarcoma (FUS) that has been identified in familial ALS is an RNA binding protein that is normally localized in the nucleus. However, its function in vivo is not fully understood. Drosophila has Cabeza (Caz) as a FUS homologue and specific knockdown of Caz in the eye imaginal disc and pupal retina using a GMR-GAL4 driver was here found to induce an abnormal morphology of the adult compound eyes, a rough eye phenotype. This was partially suppressed by expression of the apoptosis inhibitor P35. Knockdownmore » of Caz exerted no apparent effect on differentiation of photoreceptor cells. However, immunostaining with an antibody to Cut that marks cone cells revealed fusion of these and ommatidia of pupal retinae. These results indicate that Caz knockdown induces apoptosis and also inhibits differentiation of cone cells, resulting in abnormal eye morphology in adults. Mutation in EGFR pathway-related genes, such as rhomboid-1, rhomboid-3 and mirror suppressed the rough eye phenotype induced by Caz knockdown. Moreover, the rhomboid-1 mutation rescued the fusion of cone cells and ommatidia observed in Caz knockdown flies. The results suggest that Caz negatively regulates the EGFR signaling pathway required for determination of cone cell fate in Drosophila. - Highlights: • Knockdown of Cabeza induced rough eye phenotype. • Knockdown of Cabeza induced fusion of cone cells in pupal retinae. • Knockdown of Cabeza induced apoptosis in pupal retinae. • Mutation in EGFR pathway-related genes suppressed the rough eye phenotype. • Cabeza may negatively regulate the EGFR pathway.« less

NEW RECORDS AND RANGE EXTENSIONS FOR SEVERAL CHIRONOMID GENERA IN LAKE SUPERIOR

EPA Science Inventory

Recent USEPA investigations of Lake Superior benthos in Minnesota, Wisconsin, and Michigan waters have resulted in the discovery of six uncommon genera of Chironomidae. Five new records of genera for Lake Superior and five significant Nearctic range extensions are reported. New r...

Metabolism and antioxidant defense in the larval chironomid Tanytarsus minutipalpus: adjustments to diel variations in the extreme conditions of Lake Magadi

PubMed Central

Wood, Chris M.; Bergman, Harold L.; Johannsson, Ora E.; Laurent, Pierre; Chevalier, Claudine; Kisipan, Mosiany L.; Kavembe, Geraldine D.; Papah, Michael B.; Brix, Kevin V.; De Boeck, Gudrun; Maina, John N.; Ojoo, Rodi O.; Bianchini, Adalto

2017-01-01

ABSTRACT Insect larvae are reported to be a major component of the simple but highly productive trophic web found in Lake Magadi (Kenya, Africa), which is considered to be one of the most extreme aquatic environments on Earth. Previous studies show that fish must display biochemical and physiological adjustments to thrive under the extreme conditions of the lake. However, information for invertebrates is lacking. In the present study, the occurrence of the larval chironomid Tanytarsus minutipalpus is reported in Lake Magadi for the first time. Additionally, changes in larval metabolism and antioxidant defense correlated with diel variations in the extremely hostile environmental conditions of the lake are described. Wide variations in water temperature (20.2-29.3°C) and dissolved oxygen content (3.2-18.6 mg O2 l−1) were observed at different times of day, without significant change in water pH (10.0±0.03). Temperature and dissolved oxygen were higher at 13:00 h (29.3±0.4°C and 18.6±1.0 mg O2 l−1) and 19:00 h (29.3±0.8°C and 16.2±1.6 mg O2 l−1) and lower at 01:00 h (21.1±0.1°C and 10.7±0.03 mg O2 l−1) and 07:00 h (20.2±0.4°C and 3.2±0.7 mg O2 l−1). Significant and parallel increases in parameters related to metabolism (cholinesterase, glucose, cholesterol, urea, creatinine and hemoglobin) and the antioxidant system (SOD, GPx, GR, GSH and GSSG) were observed in larvae collected at 13:00 h. In contrast, no significant changes were observed in pro-oxidants (ROS and NO), TOSC and oxidative damage parameters (LPO and DNA damage). Therefore, the observed increases in temperature and dissolved O2 content in Lake Magadi were associated with changes in the antioxidant system of T. minutipalpus larvae. Adjustments performed by the chironomid larvae were efficient in maintaining body homeostasis, as well as protecting biomolecules against oxidative damage, so that oxidative stress did not occur. GSH-GSSG and GPx-GR systems appeared to play an essential role in the adjustments displayed by the chironomid larvae during the diel changes in the extreme conditions of Lake Magadi. PMID:27895051

The role of photo-electric properties of silk cocoon membrane in pupal metamorphosis: A natural solar cell

PubMed Central

Tulachan, Brindan; Srivastava, Shivansh; Kusurkar, Tejas Sanjeev; Sethy, Niroj Kumar; Bhargava, Kalpana; Singh, Sushil Kumar; Philip, Deepu; Bajpai, Alok; Das, Mainak

2016-01-01

Silkworm metamorphosis is governed by the intrinsic and extrinsic factors. One key intrinsic factor is the temporal electrical firing of the neuro-secretory cells of the dormant pupae residing inside the silk cocoon membrane (SCM). Extrinsic factors are environmental like temperature, humidity and light. The firing pattern of the cells is a function of the environmental factors that eventually controls the pupal development. How does the nervous organization of the dormant pupae sense the environment even while enclosed inside the cocoon shell? We propose that the SCM does this by capturing the incident light and converting it to electricity in addition to translating the variation in temperature and humidity as an electrical signal. The light to electricity conversion is more pronounced with ultraviolet (UV) frequency. We discovered that a UV sensitive fluorescent quercetin derivative that is present on the SCM and pupal body surface is responsible for generating the observed photo current. Based on these results, we propose an equivalent circuit model of the SCM where an overall electrical output transfers the weather information to pupae, directing its growth. We further discuss the implication of this electrical energy conversion and its utility for consumable electricity. PMID:26907586

The role of photo-electric properties of silk cocoon membrane in pupal metamorphosis: A natural solar cell.

PubMed

Tulachan, Brindan; Srivastava, Shivansh; Kusurkar, Tejas Sanjeev; Sethy, Niroj Kumar; Bhargava, Kalpana; Singh, Sushil Kumar; Philip, Deepu; Bajpai, Alok; Das, Mainak

2016-02-24

Silkworm metamorphosis is governed by the intrinsic and extrinsic factors. One key intrinsic factor is the temporal electrical firing of the neuro-secretory cells of the dormant pupae residing inside the silk cocoon membrane (SCM). Extrinsic factors are environmental like temperature, humidity and light. The firing pattern of the cells is a function of the environmental factors that eventually controls the pupal development. How does the nervous organization of the dormant pupae sense the environment even while enclosed inside the cocoon shell? We propose that the SCM does this by capturing the incident light and converting it to electricity in addition to translating the variation in temperature and humidity as an electrical signal. The light to electricity conversion is more pronounced with ultraviolet (UV) frequency. We discovered that a UV sensitive fluorescent quercetin derivative that is present on the SCM and pupal body surface is responsible for generating the observed photo current. Based on these results, we propose an equivalent circuit model of the SCM where an overall electrical output transfers the weather information to pupae, directing its growth. We further discuss the implication of this electrical energy conversion and its utility for consumable electricity.

Are adult life history traits in oriental fruit moth affected by a mild pupal heat stress?

PubMed

Zheng, Jincheng; Cheng, Xiongbin; Hoffmann, Ary A; Zhang, Bo; Ma, Chun-Sen

2017-10-01

Thermal stress at one life stage can affect fitness at a later stage in ectotherms with complex life cycles. Most relevant studies have focused on extreme stress levels, but here we also show substantial fitness effects in a moth when pupae are exposed to a relatively mild and sublethal heat stress. We consider the impact of a 35°C heat stress of 2h in three geographically separate populations of the oriental fruit moth (OFM, Grapholita molesta) from northern, middle and southern China. Heat stress negatively affected fecundity but increased adult heat resistance and adult longevity. Fitness effects were mostly consistent across populations but there were also some population differences. In the Shenyang population from northern China, there was a hormetic effect of heat on female longevity not evident in the other populations. Adults from all populations had higher LT 50 s due to heat stress after pupal exposure to the sublethal stress. These results highlight that the pupal stage is a particularly sensitive window for development and they have implications for seasonal adaptation in uncertain environments as well as changes in pest dynamics under climate warming. Copyright © 2017 Elsevier Ltd. All rights reserved.

Summer time predation on the obligatory off-host stage of an invasive ectoparasite.

PubMed

Kaunisto, Sirpa; Raunismaa, Ilkka; Kortet, Raine; Ylönen, Hannu

2016-12-01

Predation can regulate populations and strongly affect invasion success of novel prey. The deer ked (Lipoptena cervi; Linnaeus 1758) is an invasive ectoparasite of cervids that spends a long period of its life cycle outside the host. Prior to this study, virtually nothing was known about natural summer time predation on the deer ked. We aimed to evaluate the magnitude of summer time predation on L. cervi pupae in different habitats and to identify potential predators. We conducted a set of field experiments, where we exposed L. cervi pupae to various ground-dwelling vertebrate and invertebrate predators. The loss of pupae was monitored for different predator guilds. Three habitats of the moose, the main host species, were studied: (1) moist heath forest; (2) dry, logged heath forest; and (3) moist meadow. The results indicate notable summer time predation on L. cervi pupae, and the pupal predation varied within and between habitats, being lowest in the meadow habitat. We found a positive correlation between pupal loss and abundance of the common lizard (Zootoca vivipara), harvestmen (Opiliones), ground spiders (Gnaphosidae) and Formicinae-ants. We conclude that summer time predation during the pupal phase can have a notable local importance for the L. cervi abundance.

Larva of Palaemnema brasiliensis Machado (Odonata: Platystictidae), from Amazonas, Brazil.

PubMed

Neiss, Ulisses Gaspar; Hamada, Neusa

2016-02-09

The larva of Palaemnema brasiliensis Machado, 2009 is described and illustrated based on last-instar larvae and exuviae of reared larvae collected in a blackwater stream in Barcelos and Presidente Figueiredo municipalities, Amazonas state, Brazil. The larva of P. brasiliensis can be distinguished from the two South American species of the genus with described larvae (P. clementia Selys and P. mutans Calvert), mainly by presence of a single obtuse cusp on the labial palp, the presence and configuration of setae in the caudal lamellae, and the proportional length of terminal filaments of the caudal lamellae. The family is recorded here for the first time in Brazilian state of Amazonas.

Environmental Quality of Upper Honey Creek: A Preliminary Assessment.

DTIC Science & Technology

1981-01-01

chironomid pupae and " Plecoptera ", which consisted of stoneflies that were too damaged for further identification. Adult and larval beetles were...11 bbei amie1 13 15 32 153 22 leopoda (mow bugs) Aselluet (forbeal) 12 3 oapoda (crayfish) ftocabue acutus acutug Plecoptera (stoneflies) 3 1 1

Aquatic ecosystem responses to Holocene climate change and biome development in boreal, central Asia

NASA Astrophysics Data System (ADS)

Mackay, Anson W.; Bezrukova, Elena V.; Leng, Melanie J.; Meaney, Miriam; Nunes, Ana; Piotrowska, Natalia; Self, Angela; Shchetnikov, Alexander; Shilland, Ewan; Tarasov, Pavel; Wang, Luo; White, Dustin

2012-05-01

Boreal ecosystems are highly vulnerable to climate change, and severe ecological impacts in the near future are virtually certain to occur. We undertook a multiproxy study on an alpine lake (ESM-1) at the modern tree-line in boreal, southern Siberia. Steppe and tundra biomes were extensive in eastern Sayan landscapes during the early Holocene. Boreal forest quickly expanded by 9.1 ka BP, and dominated the landscape until c 0.7 ka BP, when the greatest period of compositional turnover occurred. At this time, alpine meadow landscape expanded and Picea obovata colonised new habitats along river valleys and lake shorelines, because of prevailing cool, moist conditions. During the early Holocene, chironomid assemblages were dominated by cold stenotherms. Diatoms for much of the Holocene were dominated by alkaliphilous, fragilarioid taxa, up until 0.2 ka BP, when epiphytic species expanded, indicative of increased habitat availability. C/N mass ratios ranged between 9.5 and 13.5 (11.1-15.8 C/N atomic ratios), indicative of algal communities dominating organic matter contributions to bottom sediments with small, persistent contributions from vascular plants. However, δ13C values increased steadily from -34.9‰ during the early Holocene (9.3 ka BP) to -24.8‰ by 0.6 ka BP. This large shift in magnitude may be due to a number of factors, including increasing within-lake productivity, increasing disequilibrium between the isotopic balance of the lake with the atmosphere as the lake became isotopically ‘mature’, and declining soil respiration linked to small, but distinct retreat in forest biomes. The influence of climatic variables on landscape vegetation was assessed using redundancy analysis (RDA), a linear, direct ordination technique. Changes in July insolation at 60 °N significantly explained over one-fifth of the variation in species composition, while changes in estimates of northern hemisphere temperature and ice-rafted debris events in the North Atlantic were also significant, but considerably less important. The potential importance of climate and biome development (tundra, steppe, cold deciduous forest and taiga) on different trophic levels (i.e. chironomid and diatom communities) in lake ESM-1 was also assessed using RDA. Climate predictors had a more significant influence on Holocene chironomid assemblages, especially July insolation at 60 °N, estimates of regional precipitation and estimates of northern hemisphere temperature, while only the development of the taiga biome had a significant impact on these primary consumers. Diatom communities also had a small, but significant influence on Holocene chironomid populations, perhaps linked to variation in faunal feeding strategies. In contrast, climatic and biome predictors explained similar amounts of variation in the Holocene diatom assemblage (approximately 20% each), while chironomids themselves as predictors explained just under 7% of diatom variation. Lake acidity was inferred using a diatom inference model. Results suggest that after deglaciation, the lake did not undergo a process of gradual acidification, most likely due to the presence of continuous permafrost and low levels of precipitation, preventing base cations and dissolved organic carbon entering the lake (except for the period between 1.7 and 0.7 ka BP). We conclude that lakes in continental, boreal regions undergo different models of lake ontogeny than oceanic boreal regions. Unlike other regions discussed, climate is a more important driver of ecosystem change than catchment changes. We also demonstrate that the start of the period coincident with the onset of the Little Ice Age resulted in important thresholds crossed in catchment vegetation and aquatic communities.

The impact of the Cyanamid Canada Co. discharges to benthic invertebrates in the Welland River in Niagara falls, Canada.

PubMed

Dickman, M; Rygiel, G

1993-06-01

: In 1986, the International Joint Commission (IJC) recommended that the Niagara River watershed should be declared an Area of Concern (AOC). This IJC recommendation was ratified by the 4 signatories of the Great Lakes Water Quality Agreement. In order to delist an AOC, it is necessary to locate any areas of impairment within the watershed and carry out remediation projects that permit uses that were previously impaired. To this end we attempted to determine whether or not the sediments at 7 study sites near the Cyanamid Canada (Chemical) Co. were contaminated at levels that would result in the impairment of the natural biota which inhabit the watershed.The Cyanamid Canada (Chemical) Co. discharges ammonia wastes, cyanide, arsenic and a variety of heavy metals into treatment systems which ultimately discharge to the Welland River, the major Canadian tributary to the Niagara River. This portion of the Welland River near the factory was designated a Provincially significant (Class one) wetlands by the Ontario Ministry of Natural Resources. In 1986, the mean discharge to a creek from Cyanamid Canada Co. was 27,342 m(3) per day (MOE, 1987). Similar discharge volumes occurred in 1989. In 1991, the total discharge was 25,000 m(3) per day (MOE, 1991).The majority of the benthic invertebrates collected from the study area were pollution tolerant taxa (e.g., sludge worms constituted 68% of all the organisms collected). The lowest chironomid densities were observed at stations 1, 2, and 4, which were the only stations situated close to Cyanamid's discharge pipes. The absence, of clams and mayflies which burrow to greater depths than do chironomids and sludge worms, probably reflects the inability of the deeper dwelling burrowers to tolerate the contaminants which we recorded at these 3 stations. The absence of all crustaceans from these same 3 stations (stations 1, 2 and 4) when coupled with their low biotic diversity and the elevated heavy metal concentrations in the sediments were cause for concern. In addition, stations 2 and 4 displayed the highest frequency of chironomid mentum deformities.Stations 1 and 2 were located near a pipe which was one of Cyanamid Canada Company's major discharge point sources to the Welland River until a court order in 1980 stopped the company from discharging toxic material to the Welland River via that pipe. Elevated levels of cobalt (10 times above background), molybdenum (6 times above background), nickel (8 times above back-ground), tungsten (284 times above background) and zinc (20 times above background) near the abandoned discharge pipe were correlated with the presence of pollution tolerant chironomid taxa such as Polypedilum and Procladius. The highest sludge worm densities were also observed at the abandoned pipe site which was the only site where oily wastes were found in the sediments.Among the 1,275 chironomids taken from the seven Cyanamid Canada stations, the great majority were pollution tolerant taxa. The low biotic diversity and the presence of considerable numbers of pollution tolerant benthic macroinvertebrates in combination with the chemical evidence of pollutants in the sediments near many of these Cyanamid discharge sites were reasons for classifying these sites as 'impaired' as defined by the International Joint Commission.

The effect of shade on the container index and pupal productivity of the mosquitoes Aedes aegypti and Culex pipiens breeding in artificial containers.

PubMed

Vezzani, D; Albicócco, A P

2009-03-01

The aim of this study was to assess whether certain attributes of larval breeding sites are correlated with pupal productivity (i.e. numbers of pupae collected per sampling period), so that these could be used as the focus for control measures to enhance control efficiency. Therefore, the objectives were to identify the months of highest pupal productivity of Aedes aegypti (L.) and Culex pipiens L. (Diptera: Culicidae) in an urban temperate cemetery in Argentina where artificial containers of < 6 L (flower vases) were the predominant breeding habitats, to compare various measures of the productivity of sunlit and shaded containers and to determine whether the composition of the containers affected pupal productivity. Over a period of 9 months, 200 randomly chosen water-filled containers (100 sunlit and 100 shaded), out of approximately 3738 containers present (approximately 54% in shade), were examined each month within a cemetery (5 ha) in Buenos Aires (October 2006 to June 2007). In total, 3440 immatures of Cx pipiens and 1974 of Ae. aegypti were collected. The larvae : pupae ratio was 10 times greater for the former, indicating that larval mortality was greater for Cx pipiens. Both mosquito species showed a higher container index (CI) in shaded than in sunlit containers (Ae. aegypti: 12.8% vs. 6.9% [chi(2) = 17.6, P < 0.001]; Cx pipiens: 6.3% vs. 1.8% [chi(2) = 24, P < 0.001]). However, the number and the density of immatures per infested container and the number of pupae per pupa-positive container did not differ significantly between sunlit and shaded containers for either species. Therefore, the overall relative productivity of pupae per ha of Ae. aegypti and Cx pipiens was 2.3 and 1.8 times greater, respectively, in shaded than in sunlit areas as a result of the greater CIs of containers in shaded areas. Neither the CI nor the number of immatures per infested container differed significantly among container types of different materials in either lighting condition. The maximum CI and total pupal counts occurred in March for Ae. aegypti and in January and February for Cx pipiens. The estimated peak abundance of pupae in the whole cemetery reached a total of approximately 4388 in the middle of March for Ae. aegypti and approximately 1059 in the middle of January for Cx pipiens. Spearman's correlations between monthly total productivity and monthly CI were significant at P < 0.001 for Ae. aegypti (r(s) = 0.975) and P < 0.01 for Cx pipiens (r(s) = 0.869). Our findings indicate that the efficacy of control campaigns against the two most important mosquito vectors in temperate Argentina could be improved by targeting containers in shaded areas, with maximum effort during species-specific times of year when pupal productivity is at its peak.

Insulin-like molecules in the beetle Tenebrio molitor.

PubMed

Sevala, V M; Sevala, V L; Loughton, B G

1993-07-01

Immunocytochemical staining of the nervous system of larva, pupa, and adult stage of Tenebrio molitor with anti-insulin serum demonstrated insulin-like peptides in the protocerebrum, corpora allata, and suboesophageal ganglion. During pupal development, marked changes in staining intensity of the protocerebral cells were detected. The staining pattern suggests release of insulin-like peptides early on day 0 and again on day 3 of the stadium. Injections of anti-insulin at these times caused significant delays in the timing of pupal/adult ecdysis. An immunoblot of haemolymph from day-3 pupae revealed a 6.5-kDa insulin-like molecule. These results suggest that the prothoracicotropic hormone of T. molitor is an insulin-like molecule.

Contrasting response of stream detritivores to long-term nutrient enrichment

Treesearch

W.F. Cross; B.R. Johnson; J.R. Wallace; A.D. Rosemond

2005-01-01

We examined growth and production responses of two dominant stream detritivores (chironomids and Tallaperla spp. stoneflies) at opposite ends of the "slow-fast" life-history continuum and with distinct feeding characteristics (i.e., consumption of fine particulate organic matter vs. leaf litter) to a 2-yr experimental nutrient enrichment of...

Thalassomya gutae sp. n., a new marine chironomid (Diptera: Chironomidae: Telmatogetoninae) from the Brazilian coast.

PubMed

De Oliveira, Caroline Silva Neubern; Da Silva, Fabio Laurindo; Trivinho-Strixino, Susana

2013-01-01

One new species of Thalassomya Schiner, 1856 (Diptera: Chironomidae: Telmatogetoninae), T. gutae sp. n. is described and figured as male, pupa and larva. The specimen was collected in the marine zone between tidemarks, in southeastern Brazilian coast and is the first species of this genus recorded to Brazil.

Spatial and temporal variation in invertebrate consumer diets in forested and herbaceous wetlands

Treesearch

Alani N. Taylor; Darold P. Batzer

2010-01-01

Macroinvertebrates have important functional roles in wetland ecosystems, but these roles are not always well understood. This study assessed which foods invertebrate consumers assimilate within a set of wetland habitats. During 2006 and 2007, non-Tanypodinae chironomid larvae and select crustaceans (Crangonyx amphipods, Caecidotea isopods, Simocephalus cladocerans)...

OBSERVATIONS ON THE 10-DAY CHIRONOMUS TENTANS SURVIVAL AND GROWTH BIOASSAY IN EVALUATING GREAT LAKES SEDIMENTS

EPA Science Inventory

A 10-day bioassay with larval chironomids (Chironomus tentans) was used to evaluate sediment samples from harbors at Michigan City, IN, St. Joseph, MI, Grand Haven, MI and Toledo, OH for toxicity, based on the endpoints of survival, dry weight, and growth. Larval responses in se...

Life without water: cross-resistance of anhydrobiotic cell line to abiotic stresses

NASA Astrophysics Data System (ADS)

Gusev, Oleg

2016-07-01

Anhydrobiosis is an intriguing phenomenon of natural ability of some organisms to resist water loss. The larvae of Polypedilum vanderplanki, the sleeping chironomid is the largest and most complex anhydrobionts known to date. The larvae showed ability to survive variety of abiotic stresses, including outer space environment. Recently cell line (Pv11) derived from the embryonic mass of the chironomid was established. Initially sensitive to desiccation cells, are capable to "induced" anhydrobiosis, when the resistance to desiccation can be developed by pre-treatment of the cells with trehalose followed by quick desiccation. We have further conducted complex analysis of the whole genome transcription response of Pv11 cells to different abiotic stresses, including oxidative stress and irradiation. Comparative analysis showed that the gene set, responsible for formation of desiccation resistance (ARID regions in the genome) is also activated in response to other types of stresses and likely to contribute to general enhancing of the resistance of the cells to harsh environment. We have further demonstrated that the cells are able to protect recombinant proteins from harmful effect of desiccation

Species traits and environmental conditions govern the relationship between biodiversity effects across trophic levels

USGS Publications Warehouse

Spooner, D.E.; Vaughn, C.C.; Galbraith, H.S.

2012-01-01

Changing environments can have divergent effects on biodiversity-ecosystem function relationships at alternating trophic levels. Freshwater mussels fertilize stream foodwebs through nutrient excretion, and mussel species-specific excretion rates depend on environmental conditions. We asked how differences in mussel diversity in varying environments influence the dynamics between primary producers and consumers. We conducted field experiments manipulating mussel richness under summer (low flow, high temperature) and fall (moderate flow and temperature) conditions, measured nutrient limitation, algal biomass and grazing chironomid abundance, and analyzed the data with non-transgressive overyielding and tripartite biodiversity partitioning analyses. Algal biomass and chironomid abundance were best explained by trait-independent complementarity among mussel species, but the relationship between biodiversity effects across trophic levels (algae and grazers) depended on seasonal differences in mussel species' trait expression (nutrient excretion and activity level). Both species identity and overall diversity effects were related to the magnitude of nutrient limitation. Our results demonstrate that biodiversity of a resource-provisioning (nutrients and habitat) group of species influences foodweb dynamics and that understanding species traits and environmental context are important for interpreting biodiversity experiments. ?? 2011 Springer-Verlag.

Species sorting, apparent neutrality and lasting priority effects: palaeoecological lessons from an inherently dynamic natural ecosystem

NASA Astrophysics Data System (ADS)

Mergeay, J.; De Meester, L.; Verschuren, D.

2009-04-01

To assess the influence of long-term temporal processes in community assembly, we reconstructed the community changes of two dominant components of freshwater food webs, planktonic Daphnia water fleas and benthic chironomid midge larvae, in a fluctuating tropical lake through eight cycles of major lake-level fluctuation spanning 1800 years. Our results show a highly unpredictable pattern of community assembly in Daphnia, akin to neutrality, but largely dictated by long-lasting priority effects. These priority effects were likely caused by rapid population growth of resident species during lake refilling from a standing stock in a deep crater refuge, thereby pre-empting niche space for new immigrants. Contrastingly, chironomid larvae showed a more classical species sorting response to long-term environmental change, with more limited contribution of stochastic temporal processes. Overall our study emphasizes the importance of temporal processes and niche pre-emption in metacommunity ecology, and suggests a important role for mass effects in time. It also emphasizes the value of paleoecological research to improve understanding of ecological processes in natural ecosystems.

Comparative genome sequencing reveals genomic signature of extreme desiccation tolerance in the anhydrobiotic midge

PubMed Central

Gusev, Oleg; Suetsugu, Yoshitaka; Cornette, Richard; Kawashima, Takeshi; Logacheva, Maria D.; Kondrashov, Alexey S.; Penin, Aleksey A.; Hatanaka, Rie; Kikuta, Shingo; Shimura, Sachiko; Kanamori, Hiroyuki; Katayose, Yuichi; Matsumoto, Takashi; Shagimardanova, Elena; Alexeev, Dmitry; Govorun, Vadim; Wisecaver, Jennifer; Mikheyev, Alexander; Koyanagi, Ryo; Fujie, Manabu; Nishiyama, Tomoaki; Shigenobu, Shuji; Shibata, Tomoko F.; Golygina, Veronika; Hasebe, Mitsuyasu; Okuda, Takashi; Satoh, Nori; Kikawada, Takahiro

2014-01-01

Anhydrobiosis represents an extreme example of tolerance adaptation to water loss, where an organism can survive in an ametabolic state until water returns. Here we report the first comparative analysis examining the genomic background of extreme desiccation tolerance, which is exclusively found in larvae of the only anhydrobiotic insect, Polypedilum vanderplanki. We compare the genomes of P. vanderplanki and a congeneric desiccation-sensitive midge P. nubifer. We determine that the genome of the anhydrobiotic species specifically contains clusters of multi-copy genes with products that act as molecular shields. In addition, the genome possesses several groups of genes with high similarity to known protective proteins. However, these genes are located in distinct paralogous clusters in the genome apart from the classical orthologues of the corresponding genes shared by both chironomids and other insects. The transcripts of these clustered paralogues contribute to a large majority of the mRNA pool in the desiccating larvae and most likely define successful anhydrobiosis. Comparison of expression patterns of orthologues between two chironomid species provides evidence for the existence of desiccation-specific gene expression systems in P. vanderplanki. PMID:25216354

Immature Stages of Spodoptera eridania (Lepidoptera: Noctuidae): Developmental Parameters and Host Plants

PubMed Central

Montezano, Débora Goulart; Specht, Alexandre; Sosa–Gómez, Daniel Ricardo; Roque–Specht, Vânia Ferreira; de Barros, Neiva Monteiro

2014-01-01

Abstract This study aimed to detail the temporal and morphological parameters of the immature stages of southern armyworm Spodoptera eridania (Stoll, 1782) with larvae feed on artificial diet, under controlled conditions (25 ± 1°C, 70 ± 10% relative humidity and 14-h photophase) and gather information about their larval host plants. The viability of the egg, larval, pupal, and prepupal stages was 97.82, 93.62, 96.42, and 97.03%, respectively. The average duration of the egg, larval, pupal, and pre–pupal stages was 4.00, 16.18, 1.58, and 9.17 d, respectively. During the larval stage, 43.44% of females passed through seven instars, observing that the female’s development was significant slower than males. The female larvae that developed through six and seven instars exhibited a mean growth rate of 1.52 and 1.44, respectively. Female pupae were significantly larger, exhibiting faster development than males. The rearing method proved to be adequate, providing more detailed observations of the biological cycle, especially at the larval stage, and resulting in an overall survival of almost 85%. Two hundred two plant species belonging to 58 families are listed as natural hosts for S. eridania , mainly including Asteraceae, Fabaceae, Solanaceae, Poaceae, Amaranthaceae, and Malvaceae. PMID:25525103

Egg production and oviposition in the tobacco budworm: effect of age at mating

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

Proshold, F.I.; Karpenko, C.P.; Graham, C.K.

1982-01-01

Female tobacco budworms, Heliothis virescens (F.) (Lepidoptera: Noctuidae), that emerged in the laboratory contained no mature eggs, although ooecyte development had proceeded as far as yolk deposition in the ultimate egg of each ovariole. After 18 h, ca. one mature egg per ovariole was present. If the females subsequently remained unmated, maturation of additional eggs was curvilinear with age and leveled off at ca. 500 eggs per female at 120 h. If the females mated, there was an inverse relationship between egg production and age mated; maximal production occurred when females mated the first night postemergence (ca. 30 h), andmore » production then diminished until females mating at 5 days or more laid only slightly more eggs than virgin females. However, there was also a direct relationship between length of life and age of mating. Females that mated at 1 or 2 days showed a signficant correlation between numbers of eggs produced and longevity and between numbers of eggs and pupal weight. Virgin females and females that mated at 3 days showed a significant correlation between eggs and longevity but not between eggs and pupal weight. There was no significant correlation between eggs and pupal weight or longevity for females that mated at 5 days or later.« less

Transcriptomic and metabolomic profiles of Chinese citrus fly, Bactrocera minax (Diptera: Tephritidae), along with pupal development provide insight into diapause program

PubMed Central

Fan, Huan; Xiong, Ke-Cai; Liu, Ying-Hong

2017-01-01

The Chinese citrus fly, Bactrocera minax (Enderlein), is a devastating citrus pest in Asia. This univoltine insect enters obligatory pupal diapause in each generation, while little is known about the course and the molecular mechanisms of diapause. In this study, the course of diapause was determined by measuring the respiratory rate throughout the pupal stage. In addition, the variation of transcriptomic and metabolomic profiles of pupae at five developmental stages (pre-, early-, middle-, late-, and post-diapause) were evaluated by next-generation sequencing technology and 1H nuclear magnetic resonance spectroscopy (NMR), respectively. A total of 4,808 genes were significantly altered in ten pairwise comparisons, representing major shifts in metabolism and signal transduction as well as endocrine system and digestive system. Gene expression profiles were validated by qRT-PCR analysis. In addition, 48 metabolites were identified and quantified by 1H NMR. Nine of which significantly contributed to the variation in the metabolomic profiles, especially proline and trehalose. Moreover, the samples collected within diapause maintenance (early-, middle-, and late-diapause) only exhibited marginal transcriptomic and metabolomic variation with each other. These findings greatly improve our understanding of B. minax diapause and lay the foundation for further pertinent studies. PMID:28704500

Nutritional and non-nutritional food components modulate phenotypic variation but not physiological trade-offs in an insect.

PubMed

Pascacio-Villafán, Carlos; Williams, Trevor; Birke, Andrea; Aluja, Martín

2016-07-12

Our understanding of how food modulates animal phenotypes and mediate trade-offs between life-history traits has benefited greatly from the study of combinations of nutritional and non-nutritional food components, such as plant secondary metabolites. We used a fruit fly pest, Anastrepha ludens, to examine phenotypic variation across larval, pupal and adult stages as a function of larval food with varying nutrient balance and content of chlorogenic acid, a secondary metabolite. Larval insects that fed on carbohydrate-biased diets relative to protein exhibited longer larval and pupal developmental periods, were often heavier as pupae and resisted desiccation and starvation for longer periods in the adult stage than insects fed on highly protein-biased diets. Except for a potential conflict between pupal development time and adult desiccation and starvation resistance, we did not detect physiological trade-offs mediated by the nutritional balance in larval food. Chlorogenic acid affected A. ludens development in a concentration and nutrient-dependent manner. Nutrients and host plant secondary metabolites in the larval diet induced changes in A. ludens phenotype and could influence fruit fly ecological interactions. We provide a unique experimental and modelling approach useful in generating predictive models of life history traits in a variety of organisms.

Nutritional and non-nutritional food components modulate phenotypic variation but not physiological trade-offs in an insect

PubMed Central

Pascacio-Villafán, Carlos; Williams, Trevor; Birke, Andrea; Aluja, Martín

2016-01-01

Our understanding of how food modulates animal phenotypes and mediate trade-offs between life-history traits has benefited greatly from the study of combinations of nutritional and non-nutritional food components, such as plant secondary metabolites. We used a fruit fly pest, Anastrepha ludens, to examine phenotypic variation across larval, pupal and adult stages as a function of larval food with varying nutrient balance and content of chlorogenic acid, a secondary metabolite. Larval insects that fed on carbohydrate-biased diets relative to protein exhibited longer larval and pupal developmental periods, were often heavier as pupae and resisted desiccation and starvation for longer periods in the adult stage than insects fed on highly protein-biased diets. Except for a potential conflict between pupal development time and adult desiccation and starvation resistance, we did not detect physiological trade-offs mediated by the nutritional balance in larval food. Chlorogenic acid affected A. ludens development in a concentration and nutrient-dependent manner. Nutrients and host plant secondary metabolites in the larval diet induced changes in A. ludens phenotype and could influence fruit fly ecological interactions. We provide a unique experimental and modelling approach useful in generating predictive models of life history traits in a variety of organisms. PMID:27406923

Description of Rhagoletis cerasi (Diptera: Tephritidae) Pupal Developmental Stages: Indications of Prolonged Diapause

PubMed Central

Papanastasiou, Stella A.; Papadopoulos, Nikos T.

2014-01-01

Abstract The European cherry fruit fly, Rhagoletis cerasi (L.) (Diptera: Tephritidae), is the key pest of sweet and sour cherries in many European countries and west Asia. It is a univoltine species of the west Palaearctic zone that undergoes obligatory pupal diapause. In this study, the development of R. cerasi pupae that were brought to an optimum temperature for postdiapause development following a long chilling period is described. The six most representative developmental stages within the puparium are illustrated, and the developmental progression among the stages after the end of the chilling period is quantified. Within 20 d postchilling, there was a gradual progress from stage I to pharate adult. However, ∼30% of the pupae remained at the transitional stage II, after 20 d at 25°C (optimum temperature for development). This suggests that a proportion of pupae remain at an intermediate developmental stage for an extended period of time that goes beyond 20 d postchilling. The pupal stage II might be related to diapause termination and responsiveness to environmental cues. It may also define the time before developmental progress to pharate adult. This finding agrees with previous studies proposing that a number of R. cerasi pupae undergo prolonged diapause, though the morphological characteristics of these pupae have never been described before. PMID:25399427

Chemically mediated group formation in soil-dwelling larvae and pupae of the beetle Trypoxylus dichotomus

NASA Astrophysics Data System (ADS)

Kojima, Wataru; Ishikawa, Yukio; Takanashi, Takuma

2014-09-01

Many insects form groups through interactions among individuals, and these are often mediated by chemical, acoustic, or visual cues and signals. In spite of the diversity of soil-dwelling insects, their aggregation behaviour has not been examined as extensively as that of aboveground species. We investigated the aggregation mechanisms of larvae of the Japanese rhinoceros beetle Trypoxylus dichotomus, which live in groups in humus soil. In two-choice laboratory tests, 2nd- and 3rd-instar larvae gathered at conspecific larvae irrespective of the kinship. The ablation of maxillae, which bear chemosensilla, abolished aggregation behaviour. Intact larvae also exhibited aggregation behaviour towards a larval homogenate. These results suggest that larval aggregation is mediated by chemical cues. We also demonstrated that the mature larvae of T. dichotomus built their pupal cells close to a mesh bag containing a conspecific pupal cell, which indicated that larvae utilize chemical cues emanating from these cells to select the pupation site. Thus, the larvae of T. dichotomus may use chemical cues from the conspecifics in two different contexts, i.e. larval aggregation and pupation site selection. Using conspecific cues, larvae may be able to choose suitable locations for foraging or building pupal cells. The results of the present study highlight the importance of chemical information in belowground ecology.

Aspartate Decarboxylase is Required for a Normal Pupa Pigmentation Pattern in the Silkworm, Bombyx mori.

PubMed

Dai, Fangyin; Qiao, Liang; Cao, Cun; Liu, Xiaofan; Tong, Xiaoling; He, Songzhen; Hu, Hai; Zhang, Li; Wu, Songyuan; Tan, Duan; Xiang, Zhonghuai; Lu, Cheng

2015-06-16

The pigmentation pattern of Lepidoptera varies greatly in different development stages. To date, the effects of key genes in the melanin metabolism pathway on larval and adult body color are distinct, yet the effects on pupal pigmentation remains unclear. In the silkworm, Bombyx mori, the black pupa (bp) mutant is only specifically melanized at the pupal stage. Using positional cloning, we found that a mutation in the Aspartate decarboxylase gene (BmADC) is causative in the bp mutant. In the bp mutant, a SINE-like transposon with a length of 493 bp was detected ~2.2 kb upstream of the transcriptional start site of BmADC. This insertion causes a sharp reduction in BmADC transcript levels in bp mutants, leading to deficiency of β-alanine and N-β-alanyl dopamine (NBAD), but accumulation of dopamine. Following injection of β-alanine into bp mutants, the color pattern was reverted that of the wild-type silkworms. Additionally, melanic pupae resulting from knock-down of BmADC in the wild-type strain were obtained. These findings show that BmADC plays a crucial role in melanin metabolism and in the pigmentation pattern of the silkworm pupal stage. Finally, this study contributes to a better understanding of pupa pigmentation patterns in Lepidoptera.

Aspartate Decarboxylase is Required for a Normal Pupa Pigmentation Pattern in the Silkworm, Bombyx mori

PubMed Central

Dai, Fangyin; Qiao, Liang; Cao, Cun; Liu, Xiaofan; Tong, Xiaoling; He, Songzhen; Hu, Hai; Zhang, Li; Wu, Songyuan; Tan, Duan; Xiang, Zhonghuai; Lu, Cheng

2015-01-01

The pigmentation pattern of Lepidoptera varies greatly in different development stages. To date, the effects of key genes in the melanin metabolism pathway on larval and adult body color are distinct, yet the effects on pupal pigmentation remains unclear. In the silkworm, Bombyx mori, the black pupa (bp) mutant is only specifically melanized at the pupal stage. Using positional cloning, we found that a mutation in the Aspartate decarboxylase gene (BmADC) is causative in the bp mutant. In the bp mutant, a SINE-like transposon with a length of 493 bp was detected ~2.2 kb upstream of the transcriptional start site of BmADC. This insertion causes a sharp reduction in BmADC transcript levels in bp mutants, leading to deficiency of β-alanine and N-β-alanyl dopamine (NBAD), but accumulation of dopamine. Following injection of β-alanine into bp mutants, the color pattern was reverted that of the wild-type silkworms. Additionally, melanic pupae resulting from knock-down of BmADC in the wild-type strain were obtained. These findings show that BmADC plays a crucial role in melanin metabolism and in the pigmentation pattern of the silkworm pupal stage. Finally, this study contributes to a better understanding of pupa pigmentation patterns in Lepidoptera. PMID:26077025

Large-scale identification of differentially expressed genes during pupa development reveals solute carrier gene is essential for pupal pigmentation in Chilo suppressalis.

PubMed

Sun, Yang; Huang, Shuijin; Wang, Shuping; Guo, Dianhao; Ge, Chang; Xiao, Huamei; Jie, Wencai; Yang, Qiupu; Teng, Xiaolu; Li, Fei

2017-04-01

Insects undergo metamorphosis, involving an abrupt change in body structure through cell growth and differentiation. Rice stem stripped borer (SSB), Chilo suppressalis, is one of the most destructive rice pests. However, little is known about the regulation mechanism of metamorphosis development in this notorious insect pest. Here, we studied the expression of 22,197 SSB genes at seven time points during pupa development with a customized microarray, identifying 622 differentially expressed genes (DEG) during pupa development. Gene ontology (GO) analysis of these DEGs indicated that the genes related to substance metabolism were highly expressed in the early pupa, which participate in the physiological processes of larval tissue disintegration at these stages. In comparison, highly expressed genes in the late pupal stages were mainly associated with substance biosynthesis, consistent with adult organ formation at these stages. There were 27 solute carrier (SLC) genes that were highly expressed during pupa development. We knocked down SLC22A3 at the prepupal stage, demonstrating that silencing SLC22A3 induced a deficiency in pupa stiffness and pigmentation. The RNAi-treated individuals had white and soft pupa, suggesting that this gene has an essential role in pupal development. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemically mediated group formation in soil-dwelling larvae and pupae of the beetle Trypoxylus dichotomus.

PubMed

Kojima, Wataru; Ishikawa, Yukio; Takanashi, Takuma

2014-09-01

Many insects form groups through interactions among individuals, and these are often mediated by chemical, acoustic, or visual cues and signals. In spite of the diversity of soil-dwelling insects, their aggregation behaviour has not been examined as extensively as that of aboveground species. We investigated the aggregation mechanisms of larvae of the Japanese rhinoceros beetle Trypoxylus dichotomus, which live in groups in humus soil. In two-choice laboratory tests, 2nd- and 3rd-instar larvae gathered at conspecific larvae irrespective of the kinship. The ablation of maxillae, which bear chemosensilla, abolished aggregation behaviour. Intact larvae also exhibited aggregation behaviour towards a larval homogenate. These results suggest that larval aggregation is mediated by chemical cues. We also demonstrated that the mature larvae of T. dichotomus built their pupal cells close to a mesh bag containing a conspecific pupal cell, which indicated that larvae utilize chemical cues emanating from these cells to select the pupation site. Thus, the larvae of T. dichotomus may use chemical cues from the conspecifics in two different contexts, i.e. larval aggregation and pupation site selection. Using conspecific cues, larvae may be able to choose suitable locations for foraging or building pupal cells. The results of the present study highlight the importance of chemical information in belowground ecology.

Holocene temperature shifts around Greenland: Paleolimnological approaches to quantifying past warmth and documenting its consequences

NASA Astrophysics Data System (ADS)

Axford, Y.; Lasher, G. E.; McFarlin, J. M.; Francis, D. R.; Kelly, M. A.; Langdon, P. G.; Levy, L.; Osburn, M. R.; Osterberg, E. C.

2015-12-01

Insolation-driven warmth across the Arctic during the early to middle Holocene (the Holocene Thermal Maximum, or HTM) represents a geologically accessible analog for future warming and its impacts. Improved constraints on the magnitude and seasonality of HTM warmth around Greenland's margins can advance the use of paleoclimate data to test and improve climate and ice sheet models. Here we present an overview of our recent efforts to reconstruct climate through the Holocene around the margins of the Greenland Ice Sheet using multiple proxies in lake sediments. We use insect (chironomid) assemblages to derive quantitative estimates of Holocene temperatures at sites with minimal soil and vegetation development near the eastern, northwestern and western margins of the ice sheet. Our chironomid-based temperature reconstructions consistently imply HTM July air temperatures 3 to 4.5 °C warmer than the pre-industrial late Holocene in these sectors of Greenland. The timing of reconstructed peak warmth differs between sites, with onset varying from ~10 ka to ~6.5 ka, but in good agreement with glacial geology and other evidence from each region. Our reconstructed temperature anomalies are larger than those typically inferred from annually-integrated indicators from the ice sheet itself, but comparable to the few other quantitative summer temperature estimates available from beyond the ice sheet on Greenland. Additional records are needed to confirm the magnitude of HTM warmth and to better define its seasonality and spatial pattern. To provide independent constraints on paleotemperatures and to elucidate additional aspects of Holocene paleoclimate, we are also employing oxygen isotopes of chironomid remains and other aquatic organic materials, and molecular organic proxies, in parallel (see Lasher et al. and McFarlin et al., this meeting). Combined with glacial geologic evidence, these multi-proxy records elucidate diverse aspects of HTM climate around Greenland - including temperature, hydroclimate, and the response of Greenland's glaciers to past climate change.

Multi-scale approach to the environmental factors effects on spatio-temporal variability of Chironomus salinarius (Diptera: Chironomidae) in a French coastal lagoon

NASA Astrophysics Data System (ADS)

Cartier, V.; Claret, C.; Garnier, R.; Fayolle, S.; Franquet, E.

2010-03-01

The complexity of the relationships between environmental factors and organisms can be revealed by sampling designs which consider the contribution to variability of different temporal and spatial scales, compared to total variability. From a management perspective, a multi-scale approach can lead to time-saving. Identifying environmental patterns that help maintain patchy distribution is fundamental in studying coastal lagoons, transition zones between continental and marine waters characterised by great environmental variability on spatial and temporal scales. They often present organic enrichment inducing decreased species richness and increased densities of opportunist species like C hironomus salinarius, a common species that tends to swarm and thus constitutes a nuisance for human populations. This species is dominant in the Bolmon lagoon, a French Mediterranean coastal lagoon under eutrophication. Our objective was to quantify variability due to both spatial and temporal scales and identify the contribution of different environmental factors to this variability. The population of C. salinarius was sampled from June 2007 to June 2008 every two months at 12 sites located in two areas of the Bolmon lagoon, at two different depths, with three sites per area-depth combination. Environmental factors (temperature, dissolved oxygen both in sediment and under water surface, sediment organic matter content and grain size) and microbial activities (i.e. hydrolase activities) were also considered as explanatory factors of chironomid densities and distribution. ANOVA analysis reveals significant spatial differences regarding the distribution of chironomid larvae for the area and the depth scales and their interaction. The spatial effect is also revealed for dissolved oxygen (water), salinity and fine particles (area scale), and for water column depth. All factors but water column depth show a temporal effect. Spearman's correlations highlight the seasonal effect (temperature, dissolved oxygen in sediment and water) as well as the effect of microbial activities on chironomid larvae. Our results show that a multi-scale approach identifies patchy distribution, even when there is relative environmental homogeneity.

Anhydrobiosis-Associated Nuclear DNA Damage and Repair in the Sleeping Chironomid: Linkage with Radioresistance

PubMed Central

Vanyagina, Veronica; Malutina, Ludmila; Cornette, Richard; Sakashita, Tetsuya; Hamada, Nobuyuki; Kikawada, Takahiro; Kobayashi, Yasuhiko; Okuda, Takashi

2010-01-01

Anhydrobiotic chironomid larvae can withstand prolonged complete desiccation as well as other external stresses including ionizing radiation. To understand the cross-tolerance mechanism, we have analyzed the structural changes in the nuclear DNA using transmission electron microscopy and DNA comet assays in relation to anhydrobiosis and radiation. We found that dehydration causes alterations in chromatin structure and a severe fragmentation of nuclear DNA in the cells of the larvae despite successful anhydrobiosis. Furthermore, while the larvae had restored physiological activity within an hour following rehydration, nuclear DNA restoration typically took 72 to 96 h. The DNA fragmentation level and the recovery of DNA integrity in the rehydrated larvae after anhydrobiosis were similar to those of hydrated larvae irradiated with 70 Gy of high-linear energy transfer (LET) ions (4He). In contrast, low-LET radiation (gamma-rays) of the same dose caused less initial damage to the larvae, and DNA was completely repaired within within 24 h. The expression of genes encoding the DNA repair enzymes occurred upon entering anhydrobiosis and exposure to high- and low-LET radiations, indicative of DNA damage that includes double-strand breaks and their subsequent repair. The expression of antioxidant enzymes-coding genes was also elevated in the anhydrobiotic and the gamma-ray-irradiated larvae that probably functions to reduce the negative effect of reactive oxygen species upon exposure to these stresses. Indeed the mature antioxidant proteins accumulated in the dry larvae and the total activity of antioxidants increased by a 3–4 fold in association with anhydrobiosis. We conclude that one of the factors explaining the relationship between radioresistance and the ability to undergo anhydrobiosis in the sleeping chironomid could be an adaptation to desiccation-inflicted nuclear DNA damage. There were also similarities in the molecular response of the larvae to damage caused by desiccation and ionizing radiation. PMID:21103355

Real-Time In Vivo Imaging of Butterfly Wing Development: Revealing the Cellular Dynamics of the Pupal Wing Tissue

PubMed Central

Iwata, Masaki; Ohno, Yoshikazu; Otaki, Joji M.

2014-01-01

Butterfly wings are covered with regularly arranged single-colored scales that are formed at the pupal stage. Understanding pupal wing development is therefore crucial to understand wing color pattern formation. Here, we successfully employed real-time in vivo imaging techniques to observe pupal hindwing development over time in the blue pansy butterfly, Junonia orithya. A transparent sheet of epithelial cells that were not yet regularly arranged was observed immediately after pupation. Bright-field imaging and autofluorescent imaging revealed free-moving hemocytes and tracheal branches of a crinoid-like structure underneath the epithelium. The wing tissue gradually became gray-white, epithelial cells were arranged regularly, and hemocytes disappeared, except in the bordering lacuna, after which scales grew. The dynamics of the epithelial cells and scale growth were also confirmed by fluorescent imaging. Fluorescent in vivo staining further revealed that these cells harbored many mitochondria at the surface of the epithelium. Organizing centers for the border symmetry system were apparent immediately after pupation, exhibiting a relatively dark optical character following treatment with fluorescent dyes, as well as in autofluorescent images. The wing tissue exhibited slow and low-frequency contraction pulses with a cycle of approximately 10 to 20 minutes, mainly occurring at 2 to 3 days postpupation. The pulses gradually became slower and weaker and eventually stopped. The wing tissue area became larger after contraction, which also coincided with an increase in the autofluorescence intensity that might have been caused by scale growth. Examination of the pattern of color development revealed that the black pigment was first deposited in patches in the central areas of an eyespot black ring and a parafocal element. These results of live in vivo imaging that covered wide wing area for a long time can serve as a foundation for studying the cellular dynamics of living wing tissues in butterflies. PMID:24586829

Ecological, biological and social dimensions of dengue vector breeding in five urban settings of Latin America: a multi-country study.

PubMed

Quintero, Juliana; Brochero, Helena; Manrique-Saide, Pablo; Barrera-Pérez, Mario; Basso, César; Romero, Sonnia; Caprara, Andrea; De Lima Cunha, Jane Cris; Beltrán-Ayala, Efraín; Mitchell-Foster, Kendra; Kroeger, Axel; Sommerfeld, Johannnes; Petzold, Max

2014-01-21

Dengue is an increasingly important public health problem in most Latin American countries and more cost-effective ways of reducing dengue vector densities to prevent transmission are in demand by vector control programs. This multi-centre study attempted to identify key factors associated with vector breeding and development as a basis for improving targeted intervention strategies. In each of 5 participant cities in Mexico, Colombia, Ecuador, Brazil and Uruguay, 20 clusters were randomly selected by grid sampling to incorporate 100 contiguous households, non-residential private buildings (businesses) and public spaces. Standardized household surveys, cluster background surveys and entomological surveys specifically targeted to obtain pupal indices for Aedes aegypti, were conducted in the dry and wet seasons. The study clusters included mainly urban low-middle class populations with satisfactory infrastructure and -except for Uruguay- favourable climatic conditions for dengue vector development. Household knowledge about dengue and "dengue mosquitoes" was widespread, mainly through mass media, but there was less awareness around interventions to reduce vector densities. Vector production (measured through pupal indices) was favoured when water containers were outdoor, uncovered, unused (even in Colombia and Ecuador where the large tanks used for household water storage and washing were predominantly productive) and -particularly during the dry season- rainwater filled. Larval infestation did not reflect productive container types. All productive container types, including those important in the dry season, were identified by pupal surveys executed during the rainy season. A number of findings are relevant for improving vector control: 1) there is a need for complementing larval surveys with occasional pupal surveys (to be conducted during the wet season) for identifying and subsequently targeting productive container types; 2) the need to raise public awareness about useful and effective interventions in productive container types specific to their area; and 3) the motivation for control services that-according to this and similar studies in Asia- dedicated, targeted vector management can make a difference in terms of reducing vector abundance.

The angiotensin-converting enzyme (ACE) gene family of Bombyx mori.

PubMed

Yan, Hai-Yan; Mita, Kazuei; Zhao, Xia; Tanaka, Yoshikazu; Moriyama, Minoru; Wang, Huabin; Iwanaga, Masashi; Kawasaki, Hideki

2017-04-15

We previously reported regarding an ecdysone-inducible angiotensin-converting enzyme (ACE) gene. We found another four ACE genes in the Bombyx genome. The present study was undertaken to clarify the evolutionally changed function of the ACE of Bombyx mori. Core regions of deduced amino acid sequences of ACE genes were compared with those of other insect ACE genes. Five Bombyx genes have the conserved Zn 2+ -binding-site motif (HEXXH); however, BmAcer4 has only one and BmAcer3 has no catalytic ligand. BmAcer1 and BmAcer2 were expressed in several organs. BmAcer3 was expressed in testes, and BmAcer4 and BmAcer5 were expressed in compound eyes; however, the transcription levels of these three genes were very low. Quantitative RT-PCR and Western analysis were conducted to determine the tissue distribution and developmental expression of BmAcer1and BmAcer2. Transcripts of BmAcer1 and BmAcer2 were found in the reproductive organs during the larval and pupal stages. BmAcer1 was dominant in fat bodies during the feeding stage and showed high expression in the epidermis, wing discs, and pupal wing tissues after the wandering stage. Its expression patterns in epidermis, wing discs, and wing tissues resembled the hemolymph ecdysteroid titer in the larval and pupal stages. Acer1 was observed in the hemolymph at all stages, appearing to be the source of it are fat bodies, wings, and epidermis, and functioning after being secreted into the hemolymph. BmAcer2 was abundant in the midgut during the feeding stage and after the wandering stage and in silk glands after the pupal stage. We conclude that the evolution of BmAcer occurred through duplication, and, thereafter, functional diversification developed. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of winter cold duration on spring phenology of the orange tip butterfly, Anthocharis cardamines.

PubMed

Stålhandske, Sandra; Lehmann, Philipp; Pruisscher, Peter; Leimar, Olof

2015-12-01

The effect of spring temperature on spring phenology is well understood in a wide range of taxa. However, studies on how winter conditions may affect spring phenology are underrepresented. Previous work on Anthocharis cardamines (orange tip butterfly) has shown population-specific reaction norms of spring development in relation to spring temperature and a speeding up of post-winter development with longer winter durations. In this experiment, we examined the effects of a greater and ecologically relevant range of winter durations on post-winter pupal development of A. cardamines of two populations from the United Kingdom and two from Sweden. By analyzing pupal weight loss and metabolic rate, we were able to separate the overall post-winter pupal development into diapause duration and post-diapause development. We found differences in the duration of cold needed to break diapause among populations, with the southern UK population requiring a shorter duration than the other populations. We also found that the overall post-winter pupal development time, following removal from winter cold, was negatively related to cold duration, through a combined effect of cold duration on diapause duration and on post-diapause development time. Longer cold durations also lead to higher population synchrony in hatching. For current winter durations in the field, the A. cardamines population of southern UK could have a reduced development rate and lower synchrony in emergence because of short winters. With future climate change, this might become an issue also for other populations. Differences in winter conditions in the field among these four populations are large enough to have driven local adaptation of characteristics controlling spring phenology in response to winter duration. The observed phenology of these populations depends on a combination of winter and spring temperatures; thus, both must be taken into account for accurate predictions of phenology.

Real-time in vivo imaging of butterfly wing development: revealing the cellular dynamics of the pupal wing tissue.

PubMed

Iwata, Masaki; Ohno, Yoshikazu; Otaki, Joji M

2014-01-01

Butterfly wings are covered with regularly arranged single-colored scales that are formed at the pupal stage. Understanding pupal wing development is therefore crucial to understand wing color pattern formation. Here, we successfully employed real-time in vivo imaging techniques to observe pupal hindwing development over time in the blue pansy butterfly, Junonia orithya. A transparent sheet of epithelial cells that were not yet regularly arranged was observed immediately after pupation. Bright-field imaging and autofluorescent imaging revealed free-moving hemocytes and tracheal branches of a crinoid-like structure underneath the epithelium. The wing tissue gradually became gray-white, epithelial cells were arranged regularly, and hemocytes disappeared, except in the bordering lacuna, after which scales grew. The dynamics of the epithelial cells and scale growth were also confirmed by fluorescent imaging. Fluorescent in vivo staining further revealed that these cells harbored many mitochondria at the surface of the epithelium. Organizing centers for the border symmetry system were apparent immediately after pupation, exhibiting a relatively dark optical character following treatment with fluorescent dyes, as well as in autofluorescent images. The wing tissue exhibited slow and low-frequency contraction pulses with a cycle of approximately 10 to 20 minutes, mainly occurring at 2 to 3 days postpupation. The pulses gradually became slower and weaker and eventually stopped. The wing tissue area became larger after contraction, which also coincided with an increase in the autofluorescence intensity that might have been caused by scale growth. Examination of the pattern of color development revealed that the black pigment was first deposited in patches in the central areas of an eyespot black ring and a parafocal element. These results of live in vivo imaging that covered wide wing area for a long time can serve as a foundation for studying the cellular dynamics of living wing tissues in butterflies.

Insect-Based Holocene (and Last Interglacial?) Paleothermometry from the E and NW Greenland Ice Sheet Margins: A Fly's-Eye View of Warmth on Greenland

NASA Astrophysics Data System (ADS)

Axford, Y.; Bigl, M.; Carrio, C.; Corbett, L. B.; Francis, D. R.; Hall, B. L.; Kelly, M. A.; Levy, L.; Lowell, T. V.; Osterberg, E. C.; Richter, N.; Roy, E.; Schellinger, G. C.

2013-12-01

Here we present new paleotemperature reconstructions based upon insect (Chironomidae) assemblages and other proxies from lake sediment cores recovered in east Greenland at ~71° N near Scoresby Sund and in northwest Greenland at ~77° N near Thule/Qaanaaq. In east Greenland, Last Chance Lake (informal name) is a small, non-glacial lake situated ~90 km east of the Greenland Ice Sheet margin. The lake preserves a sedimentary record of the entire Holocene (Levy et al. 2013). Chironomids from Last Chance Lake record cold summer temperatures (and establishment of a cold-climate fauna including abundant Oliveridia and Pseudodiamesa) during the late Holocene, preceded by summer temperatures estimated to have been 3 to 6°C warmer during the first half of the Holocene (when summer insolation forcing was greater than today). In northwest Greenland, Delta Sø and Wax Lips Lake (informal name) both preserve Holocene sediments. Here we discuss the late Holocene chironomid record from Delta Sø, whereas from Wax Lips Lake (a small, non-glacial lake situated ~2 km west of the ice sheet margin) we present a longer sedimentary and biostratigraphic record. The deeper portions of cores from Wax Lips Lake yield pre-Holocene and nonfinite radiocarbon ages, suggesting that this lake preserves sediments predating the Last Glacial Maximum. Abundant chironomids in the pre-glacial sediments appear to record interglacial conditions, and we infer that these sediments may date to the Last Interglacial (Eemian). The preservation of in situ Last Interglacial lacustrine sediments so close to the modern ice sheet margin suggests a minimally erosive glacierization style throughout the last glacial period, like that inferred for other Arctic locales such as on Baffin Island (Briner et al. 2007), ~750 km southwest of our study site. Our study sites are situated nearby key ice core sites (including NEEM, Camp Century, Agassiz and Renland) and very close to the ice sheet margin. These chironomid records therefore provide opportunities to compare climate inferences based upon ice core data and reconstructed ice margin histories with independent, biologically based estimates of air temperatures for the Holocene and possibly the Last Interglacial. Briner, J.P., Axford, Y., Forman, S.L., Miller, G.H., and Wolfe, A.P. 2007. Multiple generations of interglacial lake sediment preserved beneath the Laurentide Ice Sheet. Geology 35, 887-890. Levy, L.B., Kelly, M.A., Lowell, T.V., Hall, B.L., Hempel, L.A., Honsaker, W.M., Lusas, A.R., Howley, J.A., Axford, Y.L., 2013. Holocene fluctuations of Bregne ice cap, Scoresby Sund, east Greenland: a proxy for climate along the Greenland Ice Sheet margin. In press, Quaternary Science Reviews.

Quantitative summer and winter temperature reconstructions from pollen and chironomid data in the Baltic-Belarus area

NASA Astrophysics Data System (ADS)

Veski, Siim; Seppä, Heikki; Stančikaitė, Migle; Zernitskaya, Valentina; Reitalu, Triin; Gryguc, Gražyna; Heinsalu, Atko; Stivrins, Normunds; Amon, Leeli; Vassiljev, Jüri; Heiri, Oliver

2015-04-01

Quantitative reconstructions based on fossil pollen and chironomids are widely used and useful for long-term climate variability estimations. The Lateglacial and early Holocene period (15-8 ka BP) in the Baltic-Belarus (BB) area between 60°-51° N was characterized by sudden shifts in climate due to various climate forcings affecting the climate of the northern hemisphere and North Atlantic, including the proximity of receding ice sheets. Climate variations in BB during the LG were eminent as the southern part of the region was ice free during the Last Glacial Maximum over 19 ka BP, whereas northern Estonia became ice free no sooner than 13 ka BP. New pollen based reconstructions of summer (May-to-August) and winter (December-to-February) temperatures between 15-8 ka BP along a S-N transect in the BB area display trends in temporal and spatial changes in climate variability. These results are completed by two chironomid-based July mean temperature reconstructions (Heiri et al. 2014). The magnitude of change compared with modern temperatures was more prominent in the northern part of BB area than in the southern part. The 4 °C winter and 2 °C summer warming at the start of GI-1 was delayed in the BB area and Lateglacial maximum temperatures were reached at ca 13.6 ka BP, being 4 °C colder than the modern mean. The Younger Dryas cooling in the area was 5 °C colder than present as inferred by all proxies (Veski et al. in press). In addition, our analyses show an early Holocene divergence in winter temperature trends with modern values reaching 1 ka earlier (10 ka BP) in southern BB compared to the northern part of the region (9 ka BP). Heiri, O., Brooks, S.J., Renssen, H., Bedford, A., Hazekamp, M., Ilyashuk, B., Jeffers, E.S., Lang, B., Kirilova, E., Kuiper, S., Millet, L., Samartin, S., Toth, M., Verbruggen, F., Watson, J.E., van Asch, N., Lammertsma, E., Amon, L., Birks, H.H., Birks, J.B., Mortensen, M.F., Hoek, W.Z., Magyari, E., Muñoz Sobrino, C., Seppä, H., Tinner, W., Tonkov, S., Veski, S., Lotter, A.F., 2014. Validation of climate model-inferred regional temperature change for late-glacial Europe. Nature Communications 5:4914, doi: 10.1038/ncomms5914 Veski, S., Seppä, H., Stančikaitė, M., Zernitskaya, V., Reitalu, T., Gryguc, G., Heinsalu, A., Stivrins, N., Amon, L., Vassiljev, J., Heiri, O. (in press). Quantitative summer and winter temperature reconstructions from pollen and chironomid data between 15 and 8 ka BP in the Baltic-Belarus area. Quaternary International. doi: 10.1016/j.quaint.2014.10.059

Insect-Based Holocene (and Last Interglacial?) Paleothermometry from the E and NW Greenland Ice Sheet Margins: A Fly's-Eye View of Warmth on Greenland

NASA Astrophysics Data System (ADS)

Axford, Y.; Bigl, M.; Carrio, C.; Corbett, L. B.; Francis, D. R.; Hall, B. L.; Kelly, M. A.; Levy, L.; Lowell, T. V.; Osterberg, E. C.; Richter, N.; Roy, E.; Schellinger, G. C.

2011-12-01

Here we present new paleotemperature reconstructions based upon insect (Chironomidae) assemblages and other proxies from lake sediment cores recovered in east Greenland at ~71° N near Scoresby Sund and in northwest Greenland at ~77° N near Thule/Qaanaaq. In east Greenland, Last Chance Lake (informal name) is a small, non-glacial lake situated ~90 km east of the Greenland Ice Sheet margin. The lake preserves a sedimentary record of the entire Holocene (Levy et al. 2013). Chironomids from Last Chance Lake record cold summer temperatures (and establishment of a cold-climate fauna including abundant Oliveridia and Pseudodiamesa) during the late Holocene, preceded by summer temperatures estimated to have been 3 to 6°C warmer during the first half of the Holocene (when summer insolation forcing was greater than today). In northwest Greenland, Delta Sø and Wax Lips Lake (informal name) both preserve Holocene sediments. Here we discuss the late Holocene chironomid record from Delta Sø, whereas from Wax Lips Lake (a small, non-glacial lake situated ~2 km west of the ice sheet margin) we present a longer sedimentary and biostratigraphic record. The deeper portions of cores from Wax Lips Lake yield pre-Holocene and nonfinite radiocarbon ages, suggesting that this lake preserves sediments predating the Last Glacial Maximum. Abundant chironomids in the pre-glacial sediments appear to record interglacial conditions, and we infer that these sediments may date to the Last Interglacial (Eemian). The preservation of in situ Last Interglacial lacustrine sediments so close to the modern ice sheet margin suggests a minimally erosive glacierization style throughout the last glacial period, like that inferred for other Arctic locales such as on Baffin Island (Briner et al. 2007), ~750 km southwest of our study site. Our study sites are situated nearby key ice core sites (including NEEM, Camp Century, Agassiz and Renland) and very close to the ice sheet margin. These chironomid records therefore provide opportunities to compare climate inferences based upon ice core data and reconstructed ice margin histories with independent, biologically based estimates of air temperatures for the Holocene and possibly the Last Interglacial. Briner, J.P., Axford, Y., Forman, S.L., Miller, G.H., and Wolfe, A.P. 2007. Multiple generations of interglacial lake sediment preserved beneath the Laurentide Ice Sheet. Geology 35, 887-890. Levy, L.B., Kelly, M.A., Lowell, T.V., Hall, B.L., Hempel, L.A., Honsaker, W.M., Lusas, A.R., Howley, J.A., Axford, Y.L., 2013. Holocene fluctuations of Bregne ice cap, Scoresby Sund, east Greenland: a proxy for climate along the Greenland Ice Sheet margin. In press, Quaternary Science Reviews.

Effects of seasonality and resource limitation on organic matter turnover by Chironomidae (Diptera) in southern Appalachian headwater streams

Treesearch

Angela Romito; Susan Eggert; Jeffrey Diez; J. Wallace

2010-01-01

Despite their high abundance, secondary production, and known reliance on detrital material, the role of chironomids (Diptera) in fine particulate organic matter (FPOM) dynamics has not been well quantified. We conducted field trials using fluorescent pigment markers to estimate seasonal rates of consumption, annual secondary production, assimilation efficiency (AE),...

Simulium (Gomphostilbia) merapiense sp. nov. (Diptera: Simuliidae) from Java, Indonesia.

PubMed

Takaoka, Hiroyuki; Sofian-Azirun, Mohd; Ya'cob, Zubaidah; Chen, Chee Dhang; Low, Van Lun; Zaid, Adnan

2016-01-01

Simulium (Gomphostilbia) merapiense sp. nov. is described based on females, males, pupae, and mature larvae from Yagyakarta, Java, Indonesia. This new species is placed in the Simulium epistum species-group, and is characterized by the pupal gill with eight short filaments all arising at the same level from a short stalk, somewhat enlarged basal fenestra, entirely bare pupal head and thoracic integument, and small and short larval postgenal cleft. These characters rarely are found in the subgenus. Taxonomic notes are given to separate this new species from related species of the S. epistum species-group. © 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.

Effects of neem oil (Azadirachta indica A. Juss) on the replacement of the midgut epithelium in the lacewing Ceraeochrysa claveri during larval-pupal metamorphosis.

PubMed

Scudeler, Elton Luiz; Padovani, Carlos Roberto; Santos, Daniela Carvalho Dos

2014-06-01

Larvae of the lacewing Ceraeochrysa claveri were fed on eggs of Diatraeasaccharalis treated with neem oil at concentrations of 0.5%, 1% and 2% throughout the larval period. Pupae obtained from treated larvae were used in the study at five days after the completion of cocoon spinning to investigate the effects of neem oil on the replacement of the midgut epithelium during the larval-pupal transition. We observed that the old larval epithelium was shed into the midgut lumen and transformed into the yellow body. Old cells from the yellow body were destroyed by apoptosis and autophagy and were not affected by neem oil. However, neem oil did affect the new pupal epithelium. Cells from treated pupae showed cellular injuries such as a loss of microvilli, cytoplasmic vacuolization, an increase of glycogen stores, deformation of the rough endoplasmic reticulum and dilation of the perinuclear space. Additionally, the neem oil treatment resulted in the release of cytoplasmic protrusions, rupture of the plasma membrane and leakage of cellular debris into the midgut lumen, characteristics of cell death by necrosis. The results indicate that neem oil ingestion affects the replacement of midgut epithelium, causing cytotoxic effects that can alter the organism's physiology due to extensive cellular injuries. Copyright © 2014 Elsevier GmbH. All rights reserved.

Midgut morphological changes and autophagy during metamorphosis in sand flies.

PubMed

Malta, Juliana; Heerman, Matthew; Weng, Ju Lin; Fernandes, Kenner M; Martins, Gustavo Ferreira; Ramalho-Ortigão, Marcelo

2017-06-01

During metamorphosis, holometabolous insects undergo significant remodeling of their midgut and become able to cope with changes in dietary requirements between larval and adult stages. At this stage, insects must be able to manage and recycle available food resources in order to develop fully into adults, especially when no nutrients are acquired from the environment. Autophagy has been previously suggested to play a crucial role during metamorphosis of the mosquito. Here, we investigate the overall morphological changes of the midgut of the sand fly during metamorphosis and assess the expression profiles of the autophagy-related genes ATG1, ATG6, and ATG8, which are associated with various steps of the autophagic process. Morphological changes in the midgut start during the fourth larval instar, with epithelial degeneration followed by remodeling via the differentiation of regenerative cells in pre-pupal and pupal stages. The changes in the midgut epithelium are paired with the up-regulation of ATG1, ATG6 and ATG8 during the larva-adult transition. Vein, a putative epidermal growth factor involved in regulating epithelial midgut regeneration, is also up-regulated. Autophagy has further been confirmed in sand flies via the presence of autophagosomes residing within the cytoplasmic compartment of the pupal stages. An understanding of the underlying mechanisms of this process should aid the future management of this neglected tropical vector.

Description of Rhagoletis cerasi (Diptera: Tephritidae) pupal developmental stages: indications of prolonged diapause.

PubMed

Papanastasiou, Stella A; Papadopoulos, Nikos T

2014-01-01

The European cherry fruit fly, Rhagoletis cerasi (L.) (Diptera: Tephritidae), is the key pest of sweet and sour cherries in many European countries and west Asia. It is a univoltine species of the west Palaearctic zone that undergoes obligatory pupal diapause. In this study, the development of R. cerasi pupae that were brought to an optimum temperature for postdiapause development following a long chilling period is described. The six most representative developmental stages within the puparium are illustrated, and the developmental progression among the stages after the end of the chilling period is quantified. Within 20 d postchilling, there was a gradual progress from stage I to pharate adult. However, ∼30% of the pupae remained at the transitional stage II, after 20 d at 25°C (optimum temperature for development). This suggests that a proportion of pupae remain at an intermediate developmental stage for an extended period of time that goes beyond 20 d postchilling. The pupal stage II might be related to diapause termination and responsiveness to environmental cues. It may also define the time before developmental progress to pharate adult. This finding agrees with previous studies proposing that a number of R. cerasi pupae undergo prolonged diapause, though the morphological characteristics of these pupae have never been described before. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

Brain development in the yellow fever mosquito Aedes aegypti: a comparative immunocytochemical analysis using cross-reacting antibodies from Drosophila melanogaster.

PubMed

Mysore, Keshava; Flister, Susanne; Müller, Pie; Rodrigues, Veronica; Reichert, Heinrich

2011-12-01

Considerable effort has been directed towards understanding the organization and function of peripheral and central nervous system of disease vector mosquitoes such as Aedes aegypti. To date, all of these investigations have been carried out on adults but none of the studies addressed the development of the nervous system during the larval and pupal stages in mosquitoes. Here, we first screen a set of 30 antibodies, which have been used to study brain development in Drosophila, and identify 13 of them cross-reacting and labeling epitopes in the developing brain of Aedes. We then use the identified antibodies in immunolabeling studies to characterize general neuroanatomical features of the developing brain and compare them with the well-studied model system, Drosophila melanogaster, in larval, pupal, and adult stages. Furthermore, we use immunolabeling to document the development of specific components of the Aedes brain, namely the optic lobes, the subesophageal neuropil, and serotonergic system of the subesophageal neuropil in more detail. Our study reveals prominent differences in the developing brain in the larval stage as compared to the pupal (and adult) stage of Aedes. The results also uncover interesting similarities and marked differences in brain development of Aedes as compared to Drosophila. Taken together, this investigation forms the basis for future cellular and molecular investigations of brain development in this important disease vector. © Springer-Verlag 2011

Immature stages of Spodoptera eridania (Lepidoptera: Noctuidae): developmental parameters and host plants.

PubMed

Montezano, Débora Goulart; Specht, Alexandre; Sosa-Gómez, Daniel Ricardo; Roque-Specht, Vânia Ferreira; de Barros, Neiva Monteiro

2014-01-01

This study aimed to detail the temporal and morphological parameters of the immature stages of southern armyworm Spodoptera eridania (Stoll, 1782) with larvae feed on artificial diet, under controlled conditions (25 ± 1°C, 70 ± 10% relative humidity and 14-h photophase) and gather information about their larval host plants. The viability of the egg, larval, pupal, and prepupal stages was 97.82, 93.62, 96.42, and 97.03%, respectively. The average duration of the egg, larval, pupal, and pre-pupal stages was 4.00, 16.18, 1.58, and 9.17 d, respectively. During the larval stage, 43.44% of females passed through seven instars, observing that the female's development was significant slower than males. The female larvae that developed through six and seven instars exhibited a mean growth rate of 1.52 and 1.44, respectively. Female pupae were significantly larger, exhibiting faster development than males. The rearing method proved to be adequate, providing more detailed observations of the biological cycle, especially at the larval stage, and resulting in an overall survival of almost 85%. Two hundred two plant species belonging to 58 families are listed as natural hosts for S. eridania, mainly including Asteraceae, Fabaceae, Solanaceae, Poaceae, Amaranthaceae, and Malvaceae. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

Comparative diets of subyearling Atlantic salmon and subyearling coho salmon in Lake Ontario tributaries

USGS Publications Warehouse

Johnson, James H.; Ringler, Neil H.

2016-01-01

Restoration of Atlantic salmon (Salmo salar) in Lake Ontario could potentially be negatively affected by the presence of non-native salmonids that are naturalized in the basin. Coho salmon (Oncorhynchus kisutch) have been spawning successfully in Lake Ontario tributaries for over 40 years and their juveniles will reside in streams with juvenile Atlantic salmon for one year. This study sought to examine interspecific diet associations between these species, and to compare diets to the composition of the benthos and drift in three Lake Ontario tributaries. Aquatic insects, mainly ephemeropterans and chironomids were the major prey consumed by subyearling Atlantic salmon whereas terrestrial invertebrates made up only 3.7% of the diet. Ephemeropterans and chironomids were the primary aquatic taxa consumed by subyearling coho salmon but, as a group, terrestrial invertebrates (41.8%) were the major prey. In sympatry, Atlantic salmon fed more actively from the benthos whereas the diet of coho salmon was more similar to the drift. The different feeding pattern of each species resulted in low interspecific diet similarity. There is likely little competition between these species for food in Lake Ontario tributaries as juveniles.

Trophic relationships, feeding habits and seasonal dietary changes in an intertidal rockpool fish assemblage in the Gulf of Cadiz (NE Atlantic)

NASA Astrophysics Data System (ADS)

Compaire, Jesus C.; Cabrera, Remedios; Gómez-Cama, Carmen; Soriguer, Milagrosa C.

2016-06-01

This paper describes the use of resources and diet of nine resident fish species in the rocky intertidal zone of the Gulf of Cadiz and examines whether their populations are affected by trophic competition. A stomach content analysis of the nine species revealed that only one was herbivorous (Parablennius sanguinolentus), while the rest were mainly carnivorous (Gobius bucchichi, Gobius cobitis, Gobius paganellus, Zebrus zebrus, Salaria pavo, Lepadogaster lepadogaster, Scorpaena porcus and Tripterygion tripteronotum). The most frequently consumed prey were amphipods, isopods, polychaetes, decapods, chironomids, tanaidaceans, gastropods, copepods, cumaceans and ostracods. In most species, the occurrence of polychaetes and molluscs was higher in the cold season, whereas that of isopods, decapods, chironomids and fish increased in the warm season. In general, larger specimens consumed larger prey, with an increase in the occurrence of isopods, decapods and fish. An analysis of trophic niche breadth defined G. cobitis as generalist, G. bucchichi as opportunist and S. porcus as specialist, whereas the values obtained for the other species did not indicate a clearly defined strategy. Low diet overlap values and the segregation observed in several analyses indicated an adequate distribution of resources.

Bioturbation enhances the aerobic respiration of lake sediments in warming lakes.

PubMed

Baranov, Viktor; Lewandowski, Jörg; Krause, Stefan

2016-08-01

While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m(2) was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming. © 2016 The Authors.

Diel drift of Chironomidae larvae in a pristine Idaho mountain stream

USGS Publications Warehouse

Tilley, L.J.

1989-01-01

Simultaneous hourly net collections in a meadow and canyon reach of a mountain stream determined diel and spatial abundances of drifting Chironomidae larvae. Sixty-one taxa were identified to the lowest practical level, 52 in the meadow and 41 in the canyon. Orthocladiinae was the most abundant subfamily with 32 taxa and a 24 h mean density of 294 individuals 100 m-3 (meadow) and 26 taxa and a mean of 648 individuals 100 m-3 (canyon). Chironominae was the second most abundant subfamily. Nonchironomid invertebrates at both sites and total Chironomidae larvae (meadow) were predominantly night-drifting. Parakiefferiella and Psectrocladius were day-drifting (meadow) whereas 8 other chironomid taxa (meadow) and 2 taxa (canyon) were night-drifting. All others were aperiodic or too rare to test periodicity, Stempellinella cf brevis Edwards exhibited catastrophic drift in the canyon only. The different drift patterns between sites is attributed to greater loss of streambed habitat in the canyon compared to the meadow as streamflow decreased. Consequent crowding of chironomid larvae in the canyon caused catastrophic drift or interfered with drift periodicty. This study adds to knowledge of Chironomidae drift and shows influences on drift of hydrologic and geomorphic conditions. ?? 1989 Kluwer Academic Publishers.

Bioturbation enhances the aerobic respiration of lake sediments in warming lakes

PubMed Central

Krause, Stefan

2016-01-01

While lakes occupy less than 2% of the total surface of the Earth, they play a substantial role in global biogeochemical cycles. For instance, shallow lakes are important sites of carbon metabolism. Aerobic respiration is one of the important drivers of the carbon metabolism in lakes. In this context, bioturbation impacts of benthic animals (biological reworking of sediment matrix and ventilation of the sediment) on sediment aerobic respiration have previously been underestimated. Biological activity is likely to change over the course of a year due to seasonal changes of water temperatures. This study uses microcosm experiments to investigate how the impact of bioturbation (by Diptera, Chironomidae larvae) on lake sediment respiration changes when temperatures increase. While at 5°C, respiration in sediments with and without chironomids did not differ, at 30°C sediment respiration in microcosms with 2000 chironomids per m2 was 4.9 times higher than in uninhabited sediments. Our results indicate that lake water temperature increases could significantly enhance lake sediment respiration, which allows us to better understand seasonal changes in lake respiration and carbon metabolism as well as the potential impacts of global warming. PMID:27484649

On the bioavailability of trace metals in surface sediments: a combined geochemical and biological approach.

PubMed

Roosa, Stéphanie; Prygiel, Emilie; Lesven, Ludovic; Wattiez, Ruddy; Gillan, David; Ferrari, Benoît J D; Criquet, Justine; Billon, Gabriel

2016-06-01

The bioavailability of metals was estimated in three river sediments (Sensée, Scarpe, and Deûle Rivers) impacted by different levels of Cu, Cd, Pb, and Zn (Northern France). For that, a combination of geochemistry and biological responses (bacteria and chironomids) was used. The results obtained illustrate the complexity of the notion of "bioavailability." Indeed, geochemical indexes suggested a low toxicity, even in surface sediments with high concentrations of total metals and a predicted severe effect levels for the organisms. This was also suggested by the abundance of total bacteria as determined by DAPI counts, with high bacterial cell numbers even in contaminated areas. However, a fraction of metals may be bioavailable as it was shown for chironomid larvae which were able to accumulate an important quantity of metals in surface sediments within just a few days.We concluded that (1) the best approach to estimate bioavailability in the selected sediments is a combination of geochemical and biological approaches and that (2) the sediments in the Deûle and Scarpe Rivers are highly contaminated and may impact bacterial populations but also benthic invertebrates.

Diel feeding ecology of Slimy Sculpin in a tributary to Skaneateles Lake, New York

USGS Publications Warehouse

Chalupnicki, Marc A.; Johnson, James H.

2016-01-01

Interactions among the benthic community are typically overlooked but play an important role in fish community dynamics. We examined the diel feeding ecology of Slimy Sculpin (Cottus cognatus) from Grout Brook, a tributary to Skaneateles Lake. Of the six time periods examined, Slimy Sculpin consumed the least during the nighttime (2400 h and 0400 h). Chironomids were the major prey consumed during all time periods except for 2400 h when ephemeropterans were the major prey consumed. There was a moderate preference by Slimy Sculpin for food from the benthos (0.59 ± 0.06) with Diptera (Chironomids), Ephemeroptera (Baetidae), and Trichoptera (Brachycentridae) representing the major taxa. Slimy Sculpin appear to be opportunistic feeders selecting what is most available in the brook. Index of fullness was variable and averaged 1.15% across the diel cycle. Daily ration was measured as a function of fish dry body weight and ranged from 0.12 to 0.22. Estimates of daily consumption ranged from 0.007% to 4.0% of body weight, which corresponds to reports for other species. These findings have application in gauging the relative importance of Slimy Sculpin in streams where highly valued salmonid species also occur.

The effect of nitrogen loading on a brackish estuarine faunal community: A stable isotope approach

USGS Publications Warehouse

Keats, R.A.; Osher, L.J.; Neckles, H.A.

2004-01-01

Coastal ecosystems worldwide face increased nutrient enrichment from shoreline and watershed development and atmospheric pollution. We investigated the response of the faunal community of a small microtidal estuary dominated by Ruppia maritima (widgeon grass) in Maine, United States, to increased nitrogen loading using an in situ mesocosm enrichment experiment. Community response was characterized by assessing quantitative shifts in macroin-vertebrate community composition and identifying changes in food web structure using stable carbon and nitrogen isotope ratios of producers and consumers. The community was dominated by brackish water invertebrates including midge larvae, oligochaetes, damselfly larvae, amphipods, and ostracods. Experimental nutrient additions resulted in significantly lower densities of herbivorous chironomids and predatory damselflies and greater densities of deposit feeding oligochaetes. Grazing midge larvae (Chironomidae: Dicrotendipes, Cricotopus) consumed epiphytic algae under both natural and enriched conditions. Deposit feeding Chironomus was dependent on allochthonous sources of detritus under natural conditions and exhibited a shift to autochthonous sources of detritus under enriched conditions. Predatory Enallagma primarily consumed grazing chironomids under all but the highest loading conditions. Experimental nutrient loading resulted in an increase in generalist deposit feeders dependent on autochthonous sources of detritus.

Looking into the puparium: Micro-CT visualization of the internal morphological changes during metamorphosis of the blow fly, Calliphora vicina, with the first quantitative analysis of organ development in cyclorrhaphous dipterans.

PubMed

Martín-Vega, Daniel; Simonsen, Thomas J; Hall, Martin J R

2017-05-01

Metamorphosis of cyclorrhaphous flies takes place inside a barrel-like puparium, formed by the shrinking, hardening and darkening of the third-instar larval cuticle. The opacity of this structure hampers the visualization of the morphological changes occurring inside and therefore a full understanding of the metamorphosis process. Here, we use micro-computed tomography (micro-CT) to describe the internal morphological changes that occur during metamorphosis of the blow fly, Calliphora vicina Robineau-Desvoidy 1830 (Diptera: Calliphoridae) at a greater temporal resolution than anything hitherto published. The morphological changes were documented at 10% intervals of the total intra-puparial period, and down to 2.5% intervals during the first 20% interval, when the most dramatic morphological changes occur. Moreover, the development of an internal gas bubble, which plays an essential role during early metamorphosis, was further investigated with X-ray images and micro-CT virtual sections. The origin of this gas bubble has been largely unknown, but micro-CT virtual sections show that it is connected to one of the main tracheal trunks. Micro-CT virtual sections also provided enough resolution for determining the completion of the larval-pupal and pupal-adult apolyses, thus enabling an accurate timing of the different intra-puparial life stages. The prepupal, pupal, and pharate adult stages last for 7.5%, 22.5%, and 70% of the total intra-puparial development, respectively. Furthermore, we provide for the first time quantitative data on the development of two organ systems of the blow fly: the alimentary canal and the indirect flight muscles. There is a significant and negative correlation between the volume of the indirect flight muscles and the pre-helicoidal region of the midgut during metamorphosis. The latter occupies a large portion of the thorax during the pupal stage but narrows progressively as the indirect flight muscles increase in volume during the development of the pharate adult. © 2017 The Authors Journal of Morphology Published by Wiley Periodicals, Inc.

Ecological, biological and social dimensions of dengue vector breeding in five urban settings of Latin America: a multi-country study

PubMed Central

2014-01-01

Background Dengue is an increasingly important public health problem in most Latin American countries and more cost-effective ways of reducing dengue vector densities to prevent transmission are in demand by vector control programs. This multi-centre study attempted to identify key factors associated with vector breeding and development as a basis for improving targeted intervention strategies. Methods In each of 5 participant cities in Mexico, Colombia, Ecuador, Brazil and Uruguay, 20 clusters were randomly selected by grid sampling to incorporate 100 contiguous households, non-residential private buildings (businesses) and public spaces. Standardized household surveys, cluster background surveys and entomological surveys specifically targeted to obtain pupal indices for Aedes aegypti, were conducted in the dry and wet seasons. Results The study clusters included mainly urban low-middle class populations with satisfactory infrastructure and –except for Uruguay- favourable climatic conditions for dengue vector development. Household knowledge about dengue and “dengue mosquitoes” was widespread, mainly through mass media, but there was less awareness around interventions to reduce vector densities. Vector production (measured through pupal indices) was favoured when water containers were outdoor, uncovered, unused (even in Colombia and Ecuador where the large tanks used for household water storage and washing were predominantly productive) and –particularly during the dry season- rainwater filled. Larval infestation did not reflect productive container types. All productive container types, including those important in the dry season, were identified by pupal surveys executed during the rainy season. Conclusions A number of findings are relevant for improving vector control: 1) there is a need for complementing larval surveys with occasional pupal surveys (to be conducted during the wet season) for identifying and subsequently targeting productive container types; 2) the need to raise public awareness about useful and effective interventions in productive container types specific to their area; and 3) the motivation for control services that-according to this and similar studies in Asia- dedicated, targeted vector management can make a difference in terms of reducing vector abundance. PMID:24447796

Reconstruction of Centennial and Millennial-scale Climate and Environmental Variability during the Holocene in the Central Canadian Arctic

NASA Astrophysics Data System (ADS)

Rolland, N.; Porinchu, D.; MacDonald, G.; Moser, K.

2007-12-01

The Arctic and sub-Arctic regions are experiencing dramatic changes in surface temperature, sea-ice extent, glacial melt, river discharge, soil carbon storage and snow cover. According to the IPCC high latitude regions are expected to warm between 4°C and 7°C over the next 100 years. The magnitude of warming and the rate at which it occurs will dwarf any previous warming episodes experienced by latitude regions over the last 11,000 years. It is critical that we improve our understanding of how the Arctic and sub-Arctic regions responded to past periods of warming, especially in light of the changes these regions will be experiencing over the next 100 years. One of the lines of evidence increasingly utilized in multi-proxy paleolimnological research is the Chironomidae (Insecta: Diptera). Also known as non-biting midge flies, chironomids are ubiquitous, frequently the most abundant insects found in freshwater ecosystems and very sensitive to environmental conditions. This research uses Chironomidae to quantitatively characterize climate and environmental conditions of the continental interior of Arctic Canada during the Holocene. Spanning four major vegetation zones (boreal forest, forest-tundra, birch tundra and herb tundra), the surface samples of 80 lakes recovered from the central Canadian Arctic were used to assess the relationship of 22 environmental variables with the chironomid distribution. Redundancy analysis (RDA) identified four variables, total Kjeldahl nitrogen (TKN), pH, summer surface water temperature (SSWT) and depth, which best explain the variance in the distribution of chironomids within these ecoregions. In order to provide new quantitative estimates of SSWT, a 1-component weighted average partial least square (WA-PLS) model was developed (r2jack = 0.76, RMSEP = 1.42°C) and applied downcore in two low arctic continental Nunavut lakes located approximately 50 km and 200 km north of modern treeline. This robust midge-inferred temperature reconstruction of the Holocene thermal conditions will then be compared with previous research describing vegetation development in this region. This study provides new and important data which helps to further resolve millennial and centennial-scale climate variability in the central Canadian Arctic during the Holocene.

Effects of Didymosphenia geminata massive growth on stream communities: Smaller organisms and simplified food web structure

PubMed Central

Gomà, Joan; Prat, Narcís

2018-01-01

This study aims to contribute to the understanding of the impact of Didymosphenia geminata massive growths upon river ecosystem communities’ composition and functioning. This is the first study to jointly consider the taxonomic composition and functional structure of diatom and macroinvertebrate assemblages in order to determine changes in community structure, and the food web alterations associated with this invasive alga. This study was carried out in the Lumbreras River (Ebro Basin, La Rioja, Northern Spain), which has been affected by a considerable massive growth of D. geminata since 2011. The study shows a profound alteration in both the river community composition and in the food web structure at the sites affected by the massive growth, which is primarily due to the alteration of the environmental conditions, thus demonstrating that D. geminata has an important role as an ecosystem engineer in the river. Thick filamentous mats impede the movement of large invertebrates—especially those that move and feed up on it—and favor small, opportunistic, herbivorous organisms, mainly chironomids, that are capable of moving between filaments and are aided by the absence of large trophic competitors and predators -prey release effect-. Only small predators, such as hydra, are capable of surviving in the new environment, as they are favored by the increase in chironomids, a source of food, and by the reduction in both their own predators and other midge predators -mesopredator release-. This change in the top-down control affects the diatom community, since chironomids may feed on large diatoms, increasing the proportion of small diatoms in the substrate. The survival of small and fast-growing pioneer diatoms is also favored by the mesh of filaments, which offers them a new habitat for colonization. Simultaneously, D. geminata causes a significant reduction in the number of diatoms with similar ecological requirements (those attached to the substrate). Overall, D. geminata creates a community dominated by small organisms that is clearly different from the existing communities in the same stream where there is an absence of massive growths. PMID:29494699

Evidence of Regional Warming during the 20th Century in Alpine and Subalpine Lakes in the Western United States

NASA Astrophysics Data System (ADS)

Porinchu, D.; Reinemann, S.; Potito, A.; Moser, K.; MacDonald, G.; Munroe, J.; Mark, B.; Box, J.

2007-12-01

Subfossil midge analyses have been used to develop high-resolution (sub-decadal) reconstructions of 20th century temperature change in the Sierra Nevada, CA with success. Expansion of this earlier work to additional sites in the western United States suggests that a widespread increase in lake water temperatures has occurred in this region during the late 20th and early 21st centuries. Inference models for summer surface water temperature (SSWT) were developed combining midge abundance data from 56 lakes in the eastern Sierra Nevada, California, with subfossil midge remains from the Uinta Mountains, UT. The newly merged Sierra Nevada-Uinta Mountains calibration set contains a greater diversity of chironomid assemblages and spans a wider SSWT range than the previously published Sierra Nevada calibration set. The lakes in the merged calibration set spanned elevation, depth, and SSWT temperature ranges of 900 m, 12.7 m, and 11.3 °C, respectively. A robust inference model for SSWT (3-component WA-PLS), based on 90 lakes, had a high coefficient of determination (r2jack = 0.66) and a low RMSEP (1.4 °C). The midge-based SSWT inference model was applied to subfossil chironomid remains extracted from well-dated sediment sequences recovered from alpine and subalpine lakes in the Sierra Nevada, CA, Snake Range, NV and Uinta Mountains, UT. A close correspondence exists between the chironomid-inferred temperature profiles for the 20th and 21st centuries and mean July or summer temperatures measured at nearby meteorological stations. Application of this midge-based SSWT inference model to other intact, late Quaternary sedimentary sequences found in subalpine and alpine lakes in the Great Basin will help resolve the impact of late Quaternary and recent climate change in this region, improve our understanding of regional climate and aquatic ecosystem variability, and can be used to monitor the effects of climate change on aquatic ecosystems and establish 'baseline' conditions against which future biotic changes can be compared.

Transcriptome Analysis and Discovery of Genes Relevant to Development in Bradysia odoriphaga at Three Developmental Stages.

PubMed

Gao, Huanhuan; Zhai, Yifan; Wang, Wenbo; Chen, Hao; Zhou, Xianhong; Zhuang, Qianying; Yu, Yi; Li, Rumei

2016-01-01

Bradysia odoriphaga (Diptera: Sciaridae) is the most important pest of Chinese chive (Allium tuberosum) in Asia; however, the molecular genetics are poorly understood. To explore the molecular biological mechanism of development, Illumina sequencing and de novo assembly were performed in the third-instar, fourth-instar, and pupal B. odoriphaga. The study resulted in 16.2 Gb of clean data and 47,578 unigenes (≥125 bp) contained in 7,632,430 contigs, 46.21% of which were annotated from non-redundant protein (NR), Gene Ontology (GO), Clusters of Orthologous Groups (COG), Eukaryotic Orthologous Groups (KOG), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. It was found that 19.67% of unigenes matched the homologous species mainly, including Aedes aegypti, Culex quinquefasciatus, Ceratitis capitata, and Anopheles gambiae. According to differentially expressed gene (DEG) analysis, 143, 490, and 309 DEGs were annotated as involved in the developmental process in the GO database respectively, in the comparisons of third-instar and fourth-instar larvae, third-instar larvae and pupae, and fourth-instar larvae and pupae. Twenty-five genes were closely related to these processes, including developmental process, reproduction process, and reproductive organs development and programmed cell death (PCD). The information of unigenes assembled in B. odoriphaga through transcriptome and DEG analyses could provide a detailed genetic basis and regulated information for elaborating the developmental mechanism from the larval, pre-pupal to pupal stages of B. odoriphaga.

Impact of aquatic insect life stage and emergence strategy on sensitivity to esfenvalerate exposure.

PubMed

Palmquist, Katherine R; Jepson, Paul C; Jenkins, Jeffrey J

2008-08-01

We investigated the impact of aquatic insect life stage and emergence strategy on sensitivity to esfenvalerate, a synthetic pyrethroid insecticide, using field-collected Brachycentrus americanus Banks (Trichoptera: Brachycentridae) and Cinygmula reticulata McDunnough (Ephemeroptera: Heptageniidae) insects. Final-instar C. reticulata emergence was observed for one week following three environmentally relevant, 48-h esfenvalerate exposures (0.005, 0.01, and 0.015 microg/L). Emergence was significantly depressed following exposure to esfenvalerate and resulted from an increase in nymph mortality during the emergence process. This experiment was duplicated for late-instar C. reticulata nymphs, which were similar in size to the final-instar nymphs but were not near emergence. Late-instar C. reticulata mayflies were approximately fivefold less sensitive to esfenvalerate exposures as gauged by one-week mortality rates. Brachycentrus americanus pupal mortality was significantly increased over that in controls following 48-h esfenvalerate exposures of 0.1 and 0.2 microg/L. These response concentrations correlated closely with those for case-abandonment rates of fourth-instar B. americanus larvae (a sublethal effect of esfenvalerate exposure). Pupal mortality rates were approximately 16-fold higher than those observed in larvae. Adult female egg weight as a percentage of total body weight was significantly decreased following pupal esfenvalerate exposures of 0.05, 0.1, and 0.2 microg/L. These findings suggest that exposure to esfenvalerate may impair hemimetabolous insect emergence behaviors and may decrease fecundity in holometabolous aquatic insects.

Knockout silkworms reveal a dispensable role for juvenile hormones in holometabolous life cycle

PubMed Central

Daimon, Takaaki; Uchibori, Miwa; Nakao, Hajime; Sezutsu, Hideki; Shinoda, Tetsuro

2015-01-01

Insect juvenile hormones (JHs) prevent precocious metamorphosis and allow larvae to undergo multiple rounds of status quo molts. However, the roles of JHs during the embryonic and very early larval stages have not been fully understood. We generated and characterized knockout silkworms (Bombyx mori) with null mutations in JH biosynthesis or JH receptor genes using genome-editing tools. We found that embryonic growth and morphogenesis are largely independent of JHs in Bombyx and that, even in the absence of JHs or JH signaling, pupal characters are not formed in first- or second-instar larvae, and precocious metamorphosis is induced after the second instar at the earliest. We also show by mosaic analysis that a pupal specifier gene broad, which is dramatically up-regulated in the late stage of the last larval instar, is essential for pupal commitment in the epidermis. Importantly, the mRNA expression level of broad, which is thought to be repressed by JHs, remained at very low basal levels during the early larval instars of JH-deficient or JH signaling-deficient knockouts. Therefore, our study suggests that the long-accepted paradigm that JHs maintain the juvenile status throughout larval life should be revised because the larval status can be maintained by a JH-independent mechanism in very early larval instars. We propose that the lack of competence for metamorphosis during the early larval stages may result from the absence of an unidentified broad-inducing factor, i.e., a competence factor. PMID:26195792

Productivity and population density estimates of the dengue vector mosquito Aedes aegypti (Stegomyia aegypti) in Australia.

PubMed

Williams, C R; Johnson, P H; Ball, T S; Ritchie, S A

2013-09-01

New mosquito control strategies centred on the modifying of populations require knowledge of existing population densities at release sites and an understanding of breeding site ecology. Using a quantitative pupal survey method, we investigated production of the dengue vector Aedes aegypti (L.) (Stegomyia aegypti) (Diptera: Culicidae) in Cairns, Queensland, Australia, and found that garden accoutrements represented the most common container type. Deliberately placed 'sentinel' containers were set at seven houses and sampled for pupae over 10 weeks during the wet season. Pupal production was approximately constant; tyres and buckets represented the most productive container types. Sentinel tyres produced the largest female mosquitoes, but were relatively rare in the field survey. We then used field-collected data to make estimates of per premises population density using three different approaches. Estimates of female Ae. aegypti abundance per premises made using the container-inhabiting mosquito simulation (CIMSiM) model [95% confidence interval (CI) 18.5-29.1 females] concorded reasonably well with estimates obtained using a standing crop calculation based on pupal collections (95% CI 8.8-22.5) and using BG-Sentinel traps and a sampling rate correction factor (95% CI 6.2-35.2). By first describing local Ae. aegypti productivity, we were able to compare three separate population density estimates which provided similar results. We anticipate that this will provide researchers and health officials with several tools with which to make estimates of population densities. © 2012 The Royal Entomological Society.

Effect of two solanaceous plants on developmental and population parameters of the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae).

PubMed

Pereyra, Patricia C; Sánchez, Norma E

2006-01-01

Tuta absoluta (Meyrick) is an important tomato pest that also feeds on other host-plants from the Solanceae family. We studied the effect of two cultivated plants, tomato (Lycopersicum esculentum Mill.) and potato Solanum tuberosum L. on the development and populational parameters of T. absoluta related with host-plant suitability. Larval developmental time, pupal weight, mean fecundity and an index of host-plant quality (IPQ = pupal weight / frass weight) were estimated. Age-specific survivorship and fecundity life tables were constructed in the laboratory to evaluate the following populational parameters: net reproductive rate (Ro), intrinsic rate of increase (r) and generation time (T). Larval developmental time was shorter and pupal weight was higher (P < 0.0001) for larvae reared on tomato (P < 0.0001). Mean fecundity was not significantly different on both plants (P = 0.07) and food quality of host-plant was higher for tomato (P = 0.02). Mean population parameters on tomato were: Ro = 48.92; T = 27.98, r = 0.14; and on potato: Ro = 14.43; T = 32.35, r = 0.08. Although results showed that tomato was a more suitable host-plant and had a better nutritional quality than potato, when T. absoluta fed on potato the potential population increase requires attention. Under appropriate climatic conditions, spatial and temporal coincidence between crop and pest, T. absoluta could become a pest for the potato crop.

The marginal band system in nymphalid butterfly wings.

PubMed

Taira, Wataru; Kinjo, Seira; Otaki, Joji M

2015-01-01

Butterfly wing color patterns are highly complex and diverse, but they are believed to be derived from the nymphalid groundplan, which is composed of several color pattern systems. Among these pattern systems, the marginal band system, including marginal and submarginal bands, has rarely been studied. Here, we examined the color pattern diversity of the marginal band system among nymphalid butterflies. Marginal and submarginal bands are usually expressed as a pair of linear bands aligned with the wing margin. However, a submarginal band can be expressed as a broken band, an elongated oval, or a single dot. The marginal focus, usually a white dot at the middle of a wing compartment along the wing edge, corresponds to the pupal edge spot, one of the pupal cuticle spots that signify the locations of color pattern organizing centers. A marginal band can be expressed as a semicircle, an elongated oval, or a pair of eyespot-like structures, which suggest the organizing activity of the marginal focus. Physical damage at the pupal edge spot leads to distal dislocation of the submarginal band in Junonia almana and in Vanessa indica, suggesting that the marginal focus functions as an organizing center for the marginal band system. Taken together, we conclude that the marginal band system is developmentally equivalent to other symmetry systems. Additionally, the marginal band is likely a core element and the submarginal band a paracore element of the marginal band system, and both bands are primarily specified by the marginal focus organizing center.

Knockout silkworms reveal a dispensable role for juvenile hormones in holometabolous life cycle.

PubMed

Daimon, Takaaki; Uchibori, Miwa; Nakao, Hajime; Sezutsu, Hideki; Shinoda, Tetsuro

2015-08-04

Insect juvenile hormones (JHs) prevent precocious metamorphosis and allow larvae to undergo multiple rounds of status quo molts. However, the roles of JHs during the embryonic and very early larval stages have not been fully understood. We generated and characterized knockout silkworms (Bombyx mori) with null mutations in JH biosynthesis or JH receptor genes using genome-editing tools. We found that embryonic growth and morphogenesis are largely independent of JHs in Bombyx and that, even in the absence of JHs or JH signaling, pupal characters are not formed in first- or second-instar larvae, and precocious metamorphosis is induced after the second instar at the earliest. We also show by mosaic analysis that a pupal specifier gene broad, which is dramatically up-regulated in the late stage of the last larval instar, is essential for pupal commitment in the epidermis. Importantly, the mRNA expression level of broad, which is thought to be repressed by JHs, remained at very low basal levels during the early larval instars of JH-deficient or JH signaling-deficient knockouts. Therefore, our study suggests that the long-accepted paradigm that JHs maintain the juvenile status throughout larval life should be revised because the larval status can be maintained by a JH-independent mechanism in very early larval instars. We propose that the lack of competence for metamorphosis during the early larval stages may result from the absence of an unidentified broad-inducing factor, i.e., a competence factor.

Redescription of the pupa of Culex salinarius Coquillett and comparison with Culex nigripalpus Theobald.

PubMed

Darsie, Richard F; Day, Jonathan F

2006-09-01

The pupa of Culex salinarius is redescribed with updated chaetotaxal nomenclature and a full illustration. The pupal chaetotaxy of Cx. salinarius and the similar species Culex nigripalpus is compared.

Identifying taxonomic and functional surrogates for spring biodiversity conservation.

PubMed

Jyväsjärvi, Jussi; Virtanen, Risto; Ilmonen, Jari; Paasivirta, Lauri; Muotka, Timo

2018-02-27

Surrogate approaches are widely used to estimate overall taxonomic diversity for conservation planning. Surrogate taxa are frequently selected based on rarity or charisma, whereas selection through statistical modeling has been applied rarely. We used boosted-regression-tree models (BRT) fitted to biological data from 165 springs to identify bryophyte and invertebrate surrogates for taxonomic and functional diversity of boreal springs. We focused on these 2 groups because they are well known and abundant in most boreal springs. The best indicators of taxonomic versus functional diversity differed. The bryophyte Bryum weigelii and the chironomid larva Paratrichocladius skirwithensis best indicated taxonomic diversity, whereas the isopod Asellus aquaticus and the chironomid Macropelopia spp. were the best surrogates of functional diversity. In a scoring algorithm for priority-site selection, taxonomic surrogates performed only slightly better than random selection for all spring-dwelling taxa, but they were very effective in representing spring specialists, providing a distinct improvement over random solutions. However, the surrogates for taxonomic diversity represented functional diversity poorly and vice versa. When combined with cross-taxon complementarity analyses, surrogate selection based on statistical modeling provides a promising approach for identifying groundwater-dependent ecosystems of special conservation value, a key requirement of the EU Water Framework Directive. © 2018 Society for Conservation Biology.

Chironomid-based reconstructions of summer air temperature from lake deposits in Lyndon Stream, New Zealand spanning the MIS 3/2 transition

NASA Astrophysics Data System (ADS)

Woodward, C. A.; Shulmeister, J.

2007-01-01

We present chironomid-based temperature reconstructions from lake sediments deposited between ca 26,600 cal yr BP and 24,500 cal yr BP from Lyndon Stream, South Island, New Zealand. Summer (February mean) temperatures averaged 1 °C cooler, with a maximum inferred cooling of 3.7 °C. These estimates corroborate macrofossil and beetle-based temperature inferences from the same site and suggest climate amelioration (an interstadial) at this time. Other records from the New Zealand region also show a large degree of variability during the late Otiran glacial sequence (34,000-18,000 cal yr BP) including a phase of warming at the MIS 2/3 transition and a maximum cooling that did not occur until the global LGM (ca 20,000 cal yr BP). The very moderate cooling identified here at the MIS 2/3 transition confirms and enhances the long-standing discrepancy in New Zealand records between pollen and other proxies. Low abundances (<20%) of canopy tree pollen in records from late MIS 3 to the end of MIS 2 cannot be explained by the minor (<5 °C) cooling inferred from this and other studies unless other environmental parameters are considered. Further work is required to address this critical issue.

Food of young-of-the-year lake trout (Salvelinus namaycush) in Presque Isle Harbor, Lake Superior

USGS Publications Warehouse

Swedberg, Donald V.; Peck, James W.

1984-01-01

The food habits of young lake trout (Salvelinus namaycush) were studied by examining the digestive tracts of 293 young-of-the-year collected in Presque Isle Harbor, Lake Superior. Lake trout in the 25 to 27-mm length range started to eat food organisms before all of their yolk material was absorbed. Organisms consumed by the 25 to 27-mm young-of-the-year included Chironomidae, Copepoda (Harpacticoida, Calanoida, Cyclopoida), and Cladocerea (Daphnia spp., Bosmina sp., Chydorus sp.). Chironomid pupae and chironomid larvae accounted for 74% and 5%, respectively, of the total volume of food eaten by the young lake trout in Presque Isle Harbor. Although copepods, cladocerans, and mysids were present in many stomachs, their contribution to the total volume of food was only 15%. Some lake trout in the 32 to 54-mm length range had consumed fry of sculpin (Cottus spp.) or rainbow smelt (Osmerus mordax), but the overall contribution of fish fry to the total volume of food was only 4% (frequency of occurrence, 10%). The lake trout in Presque Isle Harbor fed heavily on planktonic organisms, sparingly on benthic organisms, and were opportunistic feeders that appeared to prey on whatever forage organisms were available in the shallow nearshore waters.

Prey preferences of aquatic insects: potential implications for the regulation of wetland mosquitoes.

PubMed

Saha, N; Aditya, G; Saha, G K

2014-03-01

Wetlands are potential sites for mosquito breeding and are thus important in the context of public health. The use of chemical and microbial controls is constrained in wetlands in view of their potential impact on the diverse biota. Biological control using generalist aquatic insects can be effective, provided a preference for mosquito larvae is exhibited. The mosquito prey preferences of water bugs and larvae of odonate species were evaluated using chironomid larvae, fish fingerlings and tadpoles as alternative prey. Manly's selectivity (αi ) values with 95% confidence intervals (CIs) were estimated to judge prey preference patterns. Multivariate analysis of variance (manova) and standardized canonical coefficients were used to test the effects of density on prey selectivity. The αi values indicated a significant preference (P < 0.05) in all of the insect predators tested for mosquito larvae over the alternative prey as a density-dependent function. On a comparative scale, chironomid larvae had the highest impact as alternative prey. In a multiple-prey experiment, predators showed a similar pattern of preference for mosquito larvae over alternative prey, reflecting a significant (P < 0.05) niche overlap. The results suggest that, in a laboratory setting, these insect predators can effectively reduce mosquito density in the presence of multiple alternative prey. © 2013 The Royal Entomological Society.

Madicolous Chironomidae from the Brazilian Atlantic Forest: a checklist with notes on altitudinal distributions (Diptera, Insecta)

PubMed Central

Shimabukuro, Erika Mayumi; Trivinho-Strixino, Susana

2018-01-01

Abstract Thin layers of water running over rocky surfaces are characteristic of madicolous habitats, which harbor a peculiar Chironomidae community. However, information on the identity, distribution, and ecology of madicolous chironomids in the Neotropical region are still sparse. The main purpose of this research is to reveal and contribute to the ecology of madicolous Chironomidae species, especially regarding their altitudinal distribution in the Atlantic Forest. Sampling was performed using our own designed emergence traps deployed from 0 to 2700 m a.s.l. in 70 sites in three mountains in southeastern Brazil. Sixty taxa of chironomids were collected and identified, of which only 22 are known to science. Most of the species showed a wider distribution than previously known, both in terms of geographic and altitudinal ranges, while others showed significant association with particular altitudinal bands (as evidenced by the indicator species analysis). Atlantic Forest mountainous regions are known to harbor one of the richest fauna in the world and have been suffering from several types of environmental impacts, including climate change, which will especially affect taxa living in specialized habitats. The narrow range of tolerance to environmental conditions verified for mountain species, and the fact that many of them are rare and endemic, make the conservation efforts in these areas indispensable. PMID:29706784

A revised annotated checklist of the Chironomidae (Insecta: Diptera) of the southeastern United States

USGS Publications Warehouse

Caldwell, Broughton A.; Hudson, Patrick L.; Lenat, David R.; Smith, David

1997-01-01

A revised annotated checklist for the chironomid midges (Diptera: Chironomidae) of the southeastern United States is presented that includes the states of Alabama, Florida, Georgia, North Carolina, South Carolina, and Tennessee. Much of the information concerns occurrence and habitat preference records based upon the authors' data, as well as published and unpublished data. Some information is also presented that includes aspects of biology, habitat preference, bibliographic sources, and nomenclatorial changes. Based upon the present work, the chironomid fauna of the southeastern states is comprised of 189 genera (172 described, 17 informally or unofficially described) and 754 species (505 described, 17 informally or unofficially described, 33 that are assumed for generic or subgeneric presence only, 197 estimated species, and 2 species groups). Several new species synonyms and generic placements are recognized. Thirty-eight genera known from the Nearctic region remain unknown from the southeastern states. Diversity of species was greatest in the subfamily Chironominae, considering named as well as unnamed and estimated species. There were no significant changes in overall regional distribution patterns of subfamilies or habitat preferences form that which has been previously reported. The greatest totals for regional records, habitat types, and state occurrences were the Coastal Plain (378), streams (271), and North Carolina (373), respectively.

Mercury bioaccumulation in aquatic biota along a salinity gradient in the Saint John River estuary.

PubMed

Reinhart, Bethany L; Kidd, Karen A; Curry, R Allen; O'Driscoll, Nelson J; Pavey, Scott A

2018-06-01

Although estuaries are critical habitats for many aquatic species, the spatial trends of toxic methylmercury (MeHg) in biota from fresh to marine waters are poorly understood. Our objective was to determine if MeHg concentrations in biota changed along a salinity gradient in an estuary. Fourspine Stickleback (Apeltes quadracus), invertebrates (snails, amphipods, and chironomids), sediments, and water were collected from ten sites along the Saint John River estuary, New Brunswick, Canada in 2015 and 2016, with salinities ranging from 0.06 to 6.96. Total mercury (proxy for MeHg) was measured in whole fish and MeHg was measured in a subset of fish, pooled invertebrates, sediments, and water. Stable sulfur (δ 34 S), carbon (δ 13 C), and nitrogen (δ 15 N) isotope values were measured to assess energy sources (S, C) and relative trophic level (N). There were increases in biotic δ 13 C and δ 34 S from fresh to more saline sites and these measures were correlated with salinity. Though aqueous MeHg was higher at the freshwater than more saline sites, only chironomid MeHg increased significantly with salinity. In the Saint John River estuary, there was little evidence that MeHg and its associated risks increased along a salinity gradient. Copyright © 2018. Published by Elsevier B.V.

Additions to the aquatic diptera (Chaoboridae, Chironomidae, Culicidae, Tabanidae, Tipulidae) fauna of the White River National Wildlife Refuge, Arkansas

USGS Publications Warehouse

Chordas, Stephen W.; Hudson, Patrick L.; Chapman, Eric G.

2004-01-01

The dipteran fauna of Arkansas is generally poorly known. A previous study of the Aquatic macroinvertebrates of the White River National Wildlife Refuge, the largest refuge in Arkansas, reported only 12 diptera taxa out of 219 taxa collected (Chordas et al., 1996). Most of the dipterans from this study were identified only to the family level. The family Chironomidae is a large, diverse group and was predicted to be much more diverse in the refuge than indicated by previous studies. In this study, Chironomidae were targeted, with other aquatic or semiaquatic dipterans also retained, in collections designed to better define the dipteran fauna of the White River National Wildlife Refuge. Adult dipterans were collected from 22 sites within the refuge using sweep-nets, two types of blacklight traps, and lighted fan traps in June of 2001. Specimens from previous studies were retrieved and identified to the lowest possible taxonomic level. A total of 4,917 specimens representing 122 taxa was collected. The 122 taxa were comprised of the following: two chaoborids, 83 chironomids, 15 culicids, nine tabanids, and 13 tipulids. Of these, 46 species are new state records for Arkansas. Nine undescribed species of chironomids were collected, and eight species records represent significant range extensions.

Life-cycle changes and zinc shortage in cadmium-tolerant midges, Chironomus riparius (Diptera), reared in the absence of cadmium

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

Postma, J.F.; Mol, S.; Larsen, H.

1995-01-01

Adaptation to selected metals is known to modify life-cycle characteristics of some invertebrates and can modify the response to other metals. The reverse process, i.e., adaptation to nonpolluted conditions in a metal-tolerant strain, was studied here for a cadmium-tolerant population of the midge Chironomus riparius to detect whether this backward adaptation followed the same lines. It appeared that cadmium-tolerant populations, reared in the absence of cadmium, continued to suffer from high mortality rates and lowered larval growth rates and reproductive success. Also, some cadmium-tolerant populations accumulated more zinc than did nontolerant populations. Successive experiments in which both cadmium-tolerant and nontolerantmore » populations were exposed to zinc indicated that the reduced growth rate and reproduction were a direct consequence of zinc shortage in tolerant midges reared in the absence of cadmium. Mortality among cadmium-tolerant midges was, however, not lowered by zinc exposure and, judged by their high mortality rates, these midges were even more sensitive to zinc than were nontolerant chironomids. It was concluded that cadmium-tolerant chironomid populations recovering from prolonged exposure are affected by an increased need for zinc as well as by an increased mortality rate as a direct consequence of their earlier adaptation process.« less

A new rhabdiasid nematode, Chabirenia cayennensis n. g., n. sp., parasitic in the glands of the buccal mucosa of a South American saurian.

PubMed

Lhermitte-Vallarino, N; Bain, O; Deharo, E; Bertani, S; Voza, T; Attout, T; Gaucher, P

2005-10-01

Chabirenia cayennensis n. g., n. sp. (Nematoda: Rhabdiasidae) is described from the teiid lizard Ameiva ameiva. A total of 139 worms were recovered, all females, from the mucous glands of the buccal cavity. The worm has a free-living phase in a homogonic life-cycle. Infective larvae are enclosed in a sheath with chequered ornamentation and composed of two exuviae. The new genus is distinct from the five known genera of the family, Pneumonema Johnston, 1916, Acanthorhabdias Pereira, 1927, Entomelas Travassos, 1930, Rhabdias Stiles and Hassall, 1905 and Neoentomelas Hasagawa, 1989, in the following characters: helical habitus, longitudinal cuticular crests, very tiny buccal cavity without thick walls and three oesophageal onchia. Several characters of this new rhabdiasid suggest the Strongylida.

A Critically Endangered new dragonfly species from Morocco: Onychogomphus boudoti sp. nov. (Odonata: Gomphidae).

PubMed

Ferreira, Sónia; Velo-Antón, Guillermo; Brochard, Christophe; Vieira, Cristiana; Alves, Paulo Célio; Thompson, David J; Watts, Phillip C; Brito, José Carlos

2014-08-25

Both sexes of Onychogomphus boudoti sp. nov. Ferreira (Odonata: Anisoptera: Gomphidae) and exuviae are described and illustrated from a single locality in Morocco. This newly discovered species differs markedly from other Onychogomphus species by the morphology of the male epiproct and the female vulvar scale. It is genetically distinct in the mitochondrial DNA and the nuclear PRMT gene from all other Western Palaearctic Onychogomphus species. The known distribution of the new species is confined to a small stream with unusual habitat characteristics in the vicinity of Khenifra, in the Middle Atlas, where it experiences low population size and limited genetic diversity. We suggest listing this species both locally and globally as "Critically Endangered" [CR (B1, B2 + abiii)] following the IUCN Red List Categories and Criteria. 

Modelling developmental changes in the carbon and nitrogen budgets of larval brachyuran crabs

NASA Astrophysics Data System (ADS)

Anger, K.

1990-03-01

The uptake and partitioning of nutritional carbon (C) and nitrogen (N) were studied during the complete larval development of a brachyuran crab, Hyas araneus, reared under constant conditions in the laboratory. Biochemical and physiological data were published in a foregoing paper, and complete budgets of C and N were now constructed from these data. Regression equations describing rates of feeding ( F), growth ( G), respiration ( R), and ammonia excretion ( U) as functions of time during individual larval moult cycles were inserted in a simulation model, in order to analyse time-dependent (i.e. developmental) patterns of variation in these parameters as well as in bioenergetic efficiencies. Absolute daily feeding rates ( F; per individual) as well as carbon and nitrogen-specific rates ( F/C, F/N) are in general maximum in early, and minimum in late stages of individual larval moult cycles (postmoult and premoult, respectively). Early crab zoeae may ingest equivalents of up to ca 40% body C and 30% body N per day, respectively, whereas megalopa larvae usually eat less than 10%. Also growth rates ( G; G/C, G/N) reveal decreasing tendencies both during individual moult cycles and, on the average, in subsequent instars. Conversion of C and N data to lipid and protein, respectively, suggests that in all larval instars there is initially an increase in the lipid: protein ratio. Protein, however, remains clearly the predominant biochemical constituent in larval biomass. The absolute and specific values of respiration ( R; R/C) and excretion ( U; U/N) vary only little during the course of individual moult cycles. Thus, their significance in relation to G increases within the C and N budgets, and net growth efficiency ( K 2) decreases concurrently. Also gross growth and assimilation efficiency ( K 2; A/F) are, in general, maximum in early stages of the moult cycle (postmoult). Biochemical data suggest that lipid utilization efficiency is particularly high in early moult cycle stages, whereas protein utilization efficiency is higher in later stages. Only the zoea II appears to accumulate lipid from food constantly with a higher conversion efficiency than protein. The cumulative C and N budgets show in subsequent larval instars conspicuously increasing figures in all of their parameters. F and G increase to a particularly high extent from the first to the second zoeal instar, whereas R, U, exuvia production ( G E), and total assimilation ( A) reveal a greater increase from the zoea II to the megalopa. Respiratory, excretory, and exuvial losses increase in subsequent larval instars at higher rates than tissue growth and, hence, K 2 decreases in the same order. In the C budget, K 2 values of 0.63 (zoea I). 0.56 (zoea II), and 0.29 (megalopa) were calculated (or: 0.56, 0.46, and 0.16 after subtraction of exuviae). In the N budget, corresponding values of 0.76, 0.66, and 0.45 (or: 0.72, 0.62, 0.38 without exuviae) were obtained. Also K 1 decreases slightly in subsequent instars, whereas A/F reveals rather an increasing tendency, at least from the zoeal instars to the megalopa. Changes in the uptake and partitioning of matter in crab larvae are discussed in relation to developmental events and changes in life style before metamorphosis.

Impact of small mammal predators on gypsy moth

Treesearch

Joseph S. Elkinton; Harvey R. Smith; Andrew M. Liebhold

1991-01-01

Research in western Massachusetts, on Cape Cod, and on Bryant Mountain in Vermont conducted over the past decade has confirmed the importance of mortality during the late larval and pupal stages to gypsy moth population dynamics.

Two New Species of the Simulium (Simulium) variegatum Species-Group of Black Flies (Diptera: Simuliidae) From Thailand.

PubMed

Takaoka, Hiroyuki; Srisuka, Wichai; Saeung, Atiporn

2017-09-01

Two new species of black flies, Simulium (Simulium) srisukai and S. (S.) kiewmaepanense, are described from specimens collected in Thailand. Both species are assigned to the Simulium variegatum species-group of the subgenus Simulium (Simulium) Latreille. They are characterized by the darkened female femora and tibiae and six inflated pupal gill filaments, and the darkened female tibiae and six ordinary thread-like pupal gill filaments, respectively. Taxonomic notes are given to separate these new species from 10 related species among the group. These new species represent the third and fourth species of the S. variegatum species-group from Thailand. © 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 Version of Record, first published online May 15, 2017 with fixed content and layout in compliance with Art. 8.1.3.2 ICZN.

Nuclear magnetic resonance microscopy of the development of the parasitoid wasp Venturia canescens within its host moth Plodia interpunctella.

PubMed

Chudek, J A; Crook, A M; Hubbard, S F; Hunter, G

1996-01-01

Nuclear magnetic resonance microscopy was used to image the parasitoid wasp Venturia canescens (Hymenoptera: Ichneumonidae) within larval and pupal instars of its host, the Indian meal moth, Plodia interpunctella (Lepidoptera: Pyralidae). The images were obtained using gradient-echo and chemical shift selective pulse sequences and clearly showed the location and shapes of the parasitoid as it developed from the L1 larva to a pupal stage within the host. The digestive, nervous, and tracheal systems of the host were identified and changes were observed as the host underwent metamorphosis. Destruction of the host tissues by the parasitoid was visible. It was found that the parasitoid first ate the fat body and digestive system of the host, allowing the host to continue to grow, and only progressed to the vital organs when its own development had neared pupation.

Chemical investigations of volatile kairomones produced by Hyphantria cunea (Drury), a host of the parasitoid Chouioia cunea Yang.

PubMed

Zhu, G; Pan, L; Zhao, Y; Zhang, X; Wang, F; Yu, Y; Fan, W; Liu, Q; Zhang, S; Li, M

2017-04-01

In tritrophic 'plants-herbivores-natural enemies' systems, there are relatively few reports concerning the role(s) of kairomones in pupal parasitism. Chouioia cunea Yang (Hymenoptera: Eulophidae), an endoparasitic chalcid wasp, parasitizes pupae of the fall webworm (Hyphantria cunea Drury). The role of host-related kairomones was investigated using electroantennogram (EAG) and behavioral techniques. Chemicals from some host stages (pupae) and host by-products (frass), induced arrestment behavior of female parasitoids, while chemicals from prepupae, were inactive. Gas chromatography-mass spectrometry analysis of volatiles collected from pupae, frass and prepupae using solid-phase microextration revealed seven compounds with carbon chain lengths ranging from C4 to C20. All of the chemicals elicited significant EAG responses in C. cunea. Y-tube olfactometer bioassays demonstrated a significant positive response of mated female C. cunea to 1-dodecene. These data provide a better understanding of the host location mechanisms of pupal parasitoid.

Selection and Suitability of an Artificial Diet for Tuta absoluta (Lepidoptera: Gelechiidae) Based on Physical and Chemical Characteristics

PubMed Central

Parra, J. R. P.

2017-01-01

Tuta absoluta (Meyrick, 1917) is a key tomato pest in South America and, recently, in Europe and Africa. To develop efficient control methods for this pest, adequate rearing protocols are desirable. As an alternative to tomato leaves (natural diet), we evaluated four artificial diets. Biological traits including larval and pupal viability and development time, pupal weight and deformations were assessed. Additionally, the optimum container size and larval density were evaluated. The diet based on casein, wheat germ and cellulose allowed the best development of T. absoluta, showing higher viability and no negative effects on larval instars and pupal weight. The best container was a glass tube measuring Ø 1 × h 6 cm, topped with waterproof cotton, with a density of three larvae. To evaluate the suitability of this diet, T. absoluta was reared during eight generations and life-table parameters were estimated for the F1, F3, F6, and F8 generations. The total viability (egg–adult) increased over the generations, reaching 75% in the eighth generation. Based on life-table estimations no differences among generations were found. The net reproductive rate (Ro) was higher than 40, the intrinsic rate of increase (rm) ranged between 0.08 and 0.11, the finite rate of increase (λ) was 1.1, the mean generation time (T) have a maximum of 44 d and doubling time ranged from 5.89–8.32 generations. These results indicated that a diet based on casein, wheat germ and cellulose was suitable for T. absoluta rearing in laboratory conditions. PMID:28042106

Side-Effects of Glyphosate to the Parasitoid Telenomus remus Nixon (Hymenoptera: Platygastridae).

PubMed

Stecca, C S; Bueno, A F; Pasini, A; Silva, D M; Andrade, K; Filho, D M Z

2016-04-01

The aim of this study was to compare the side-effects of glyphosate to the parasitoid Telenomus remus Nixon (Hymenoptera: Platygastridae) when parasitoids were exposed to this chemical at the pupal (inside host eggs) and adult stages. Bioassays were conducted under laboratory conditions according to the International Organization for Biological Control (IOBC) standard methods for testing side-effects of pesticides to egg parasitoids. Different glyphosate-based pesticides (Roundup Original®, Roundup Ready®, Roundup Transorb®, Roundup WG®, and Zapp Qi®) were tested at the same acid equivalent concentration. Treatments were classified following the IOBC toxicity categories as (1) harmless, (2) slightly harmful, (3) moderately harmful, and (4) harmful. When tested against T. remus adults, Roundup Original®, Roundup Ready®, Roundup Transorb®, and Roundup WG® reduced parasitism 2 days after parasitoid emergence, being classified as slightly harmful. Differently, when tested against T. remus pupae, all tested glyphosate-based products did not differ in their lethal effect and therefore did not reduce T. remus adult emergence or parasitism capacity, being classified as harmless. However, differences on sublethal toxicity were found. Parasitism of individuals emerging from parasitized eggs sprayed at the pupal stage of T. remus with Zapp Qi® was lower compared to control, but parasitism was still higher than 66%, and therefore, Zapp Qi® was still classified as harmless. In conclusion, all tested glyphosate-based products can be used in agriculture without negative impact to T. remus as none was classified as harmful or moderately harmful to this parasitoid when exposure occurred at the pupal or adult stages.

Global Metabolomic Analyses of the Hemolymph and Brain during the Initiation, Maintenance, and Termination of Pupal Diapause in the Cotton Bollworm, Helicoverpa armigera

PubMed Central

Lu, Yu-Xuan; Zhang, Qi; Xu, Wei-Hua

2014-01-01

A strategy known as diapause (developmental arrest) has evolved in insects to increase their survival rate under harsh environmental conditions. Diapause causes a dramatic reduction in the metabolic rate and drastically extends lifespan. However, little is known about the mechanisms underlying the metabolic changes involved. Using gas chromatography-mass spectrometry, we compared the changes in the metabolite levels in the brain and hemolymph of nondiapause- and diapause-destined cotton bollworm, Helicoverpa armigera, during the initiation, maintenance, and termination of pupal diapause. A total of 55 metabolites in the hemolymph and 52 metabolites in the brain were detected. Of these metabolites, 21 and 12 metabolite levels were altered in the diapause pupal hemolymph and brain, respectively. During diapause initiation and maintenance, the number of metabolites with increased levels in the hemolymph of the diapausing pupae is far greater than the number in the nondiapause pupae. These increased metabolites function as an energy source, metabolic intermediates, and cryoprotectants. The number of metabolites with decreased levels in the brain of diapausing pupae is far greater than the number in the nondiapause pupae. Low metabolite levels are likely to directly or indirectly repress the brain metabolic activity. During diapause termination, most of the metabolite levels in the hemolymph of the diapausing pupae rapidly decrease because they function as energy and metabolic sources that promote pupa-adult development. In conclusion, the metabolites with altered levels in the hemolymph and brain serve as energy and metabolic resources and help to maintain a low brain metabolic activity during diapause. PMID:24926789

Does targeting key-containers effectively reduce Aedes aegypti population density?

PubMed

Maciel-de-Freitas, Rafael; Lourenço-de-Oliveira, Ricardo

2011-08-01

The elimination of Aedes aegypti breeding sites has been broadly adopted worldwide to keep vector population density below a critical threshold. We observed the effectiveness of targeting the most productive containers on adult A. aegypti females density, which was evaluated weekly. Adult mosquitoes were collected weekly over 55 weeks and pupal surveys were done in intervals of 4 months to determine container productivity and guidelines for interventions. Pupal surveys indicated that water tanks (72% of pupae in first survey) and metal drums (30.7% of pupae in second survey) were the most productive container types. We observed a dramatic but short-term decrease in weekly adult female A. aegypti density after covering 733 water tanks with nylon net. A long-term decrease in female adult population density was achieved only when we covered both water tanks and metal drums. Overall, pupae abundance and pupae standing crop diminished after netting water tanks and metal drums. Pupae per person, per hectare and per house decreased gradually between the first and the third pupal surveys, suggesting that targeting the most productive container types (water tanks and metal drums) produced a reduction in adult population density and infestation levels. Overall, targeting the most productive container types caused the adult mosquito density to decrease over time, supporting the assumption that this intervention is an effective tool for dengue control. However, this effect was observed only when both water tanks and metal drums were covered, possibly due to the functional similarity between these container types, which are large, often shaded, perennial water storage containers. © 2011 Blackwell Publishing Ltd.

Native range assessment of classical biological control agents: impact of inundative releases as pre-introduction evaluation.

PubMed

Jenner, W H; Mason, P G; Cappuccino, N; Kuhlmann, U

2010-08-01

Diadromus pulchellus Wesmael (Hymenoptera: Ichneumonidae) is a pupal parasitoid under consideration for introduction into Canada for the control of the invasive leek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae). Since study of the parasitoid outside of quarantine was not permitted in Canada at the time of this project, we assessed its efficacy via field trials in its native range in central Europe. This was done by simulating introductory releases that would eventually take place in Canada when a permit for release is obtained. In 2007 and 2008, experimental leek plots were artificially infested with pest larvae to mimic the higher pest densities common in Canada. Based on a preliminary experiment showing that leek moth pupae were suitable for parasitism up to 5-6 days after pupation, D. pulchellus adults were mass-released into the field plots when the first host cocoons were observed. The laboratory-reared agents reproduced successfully in all trials and radically reduced leek moth survival. Taking into account background parasitism caused by naturally occurring D. pulchellus, the released agents parasitized at least 15.8%, 43.9%, 48.1% and 58.8% of the available hosts in the four release trials. When this significant contribution to leek moth mortality is added to previously published life tables, in which pupal parasitism was absent, the total pupal mortality increases from 60.1% to 76.7%. This study demonstrates how field trials involving environmental manipulation in an agent's native range can yield predictions of the agent's field efficacy once introduced into a novel area.

Spontaneous long-range calcium waves in developing butterfly wings.

PubMed

Ohno, Yoshikazu; Otaki, Joji M

2015-03-25

Butterfly wing color patterns emerge as the result of a regular arrangement of scales produced by epithelial scale cells at the pupal stage. These color patterns and scale arrangements are coordinated throughout the wing. However, the mechanism by which the development of scale cells is controlled across the entire wing remains elusive. In the present study, we used pupal wings of the blue pansy butterfly, Junonia orithya, which has distinct eyespots, to examine the possible involvement of Ca(2+) waves in wing development. Here, we demonstrate that the developing pupal wing tissue of the blue pansy butterfly displayed spontaneous low-frequency Ca(2+) waves in vivo that propagated slowly over long distances. Some waves appeared to be released from the immediate peripheries of the prospective eyespot and discal spot, though it was often difficult to identify the specific origins of these waves. Physical damage, which is known to induce ectopic eyespots, led to the radiation of Ca(2+) waves from the immediate periphery of the damaged site. Thapsigargin, which is a specific inhibitor of Ca(2+)-ATPases in the endoplasmic reticulum, induced an acute increase in cytoplasmic Ca(2+) levels and halted the spontaneous Ca(2+) waves. Additionally, thapsigargin-treated wings showed incomplete scale development as well as other scale and color pattern abnormalities. We identified a novel form of Ca(2+) waves, spontaneous low-frequency slow waves, which travel over exceptionally long distances. Our results suggest that spontaneous Ca(2+) waves play a critical role in the coordinated development of scale arrangements and possibly in color pattern formation in butterflies.

Effect of temperature on life history traits during immature development of Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) from Córdoba city, Argentina.

PubMed

Grech, Marta G; Sartor, Paolo D; Almirón, Walter R; Ludueña-Almeida, Francisco F

2015-06-01

We investigated how ambient temperature under fluctuating conditions affects the larval-pupal immature traits of Aedes aegypti and Culex quinquefasciatus mosquitoes from Córdoba city, Argentina, and established each species development threshold and physiological time. Based on life tables, three cohorts of each mosquito species were reared in the laboratory under small fluctuating temperatures conditions of 15.2±1.7°C, 17.9±1.6°C, 21.6±0.7°C and 25.3±0.4°C for Ae. aegypti, and 16.6±1.7°C, 18.7±1.7°C and 25.2±0.3°C for Cx. quinquefasciatus. Immature development time and survival values, and also thermal development threshold and physiological time were estimated. Development times of all larval and pupal stages of Ae. aegypti and Cx. quinquefasciatus were significantly affected by the rearing temperatures, decreasing when temperature increased. Mean Ae. aegypti total (larva+pupa) development time ranged from 21.9 to 8.6 days, at 15.2 and 25.3°C, whereas, for Cx. quinquefasciatus varied between 23.5 to 9.2 days at 16.6 and 25.2°C, respectively. Larval and pupal survival of both species was affected by different rearing temperatures, increasing in general as temperature increased. For Ae. aegypti the total immature survival ranged from 26% at 15.2°C to 92% at 21.6°C; however, temperature did not have significant effect on this variable. The total immature survival of Cx. quinquefasciatus was significantly and positively affected by temperatures, ranging from 32 to 88%, at 16.6 and 25.2°C. The temperature development threshold and the physiological time estimated for Ae. aegypti and Cx. quinquefasciatus were 11.11°C and 93.74 degree-days, and 10.96°C and 136.87 degree-days, respectively. The results of the present study showed that temperature significantly affects the larval-pupal immature traits of these mosquito species of sanitary importance, from the central region of Argentina. All the parameters recorded are useful for the development of mosquito management models. Copyright © 2015 Elsevier B.V. All rights reserved.

Supraoptimal temperatures influence the range dynamics of a non-native insect

Treesearch

Patrick C. Tobin; David R. Gray; Andrew M. Liebhold

2014-01-01

Aim. To examine the relationship between the range dynamics of the nonnative species Lymantria dispar (L.) and supraoptimal temperatures during its larval and pupal period. Location. West Virginia and Virginia, United States, North America. Methods. We linked the...

Inferring late-Holocene climate in the Ecuadorian Andes using a chironomid-based temperature inference model

NASA Astrophysics Data System (ADS)

Matthews-Bird, Frazer; Brooks, Stephen J.; Holden, Philip B.; Montoya, Encarni; Gosling, William D.

2016-06-01

Presented here is the first chironomid calibration data set for tropical South America. Surface sediments were collected from 59 lakes across Bolivia (15 lakes), Peru (32 lakes), and Ecuador (12 lakes) between 2004 and 2013 over an altitudinal gradient from 150 m above sea level (a.s.l) to 4655 m a.s.l, between 0-17° S and 64-78° W. The study sites cover a mean annual temperature (MAT) gradient of 25 °C. In total, 55 chironomid taxa were identified in the 59 calibration data set lakes. When used as a single explanatory variable, MAT explains 12.9 % of the variance (λ1/λ2 = 1.431). Two inference models were developed using weighted averaging (WA) and Bayesian methods. The best-performing model using conventional statistical methods was a WA (inverse) model (R2jack = 0.890; RMSEPjack = 2.404 °C, RMSEP - root mean squared error of prediction; mean biasjack = -0.017 °C; max biasjack = 4.665 °C). The Bayesian method produced a model with R2jack = 0.909, RMSEPjack = 2.373 °C, mean biasjack = 0.598 °C, and max biasjack = 3.158 °C. Both models were used to infer past temperatures from a ca. 3000-year record from the tropical Andes of Ecuador, Laguna Pindo. Inferred temperatures fluctuated around modern-day conditions but showed significant departures at certain intervals (ca. 1600 cal yr BP; ca. 3000-2500 cal yr BP). Both methods (WA and Bayesian) showed similar patterns of temperature variability; however, the magnitude of fluctuations differed. In general the WA method was more variable and often underestimated Holocene temperatures (by ca. -7 ± 2.5 °C relative to the modern period). The Bayesian method provided temperature anomaly estimates for cool periods that lay within the expected range of the Holocene (ca. -3 ± 3.4 °C). The error associated with both reconstructions is consistent with a constant temperature of 20 °C for the past 3000 years. We would caution, however, against an over-interpretation at this stage. The reconstruction can only currently be deemed qualitative and requires more research before quantitative estimates can be generated with confidence. Increasing the number, and spread, of lakes in the calibration data set would enable the detection of smaller climate signals.

Larva and pupa of Ctesias (s. str.) serra (Fabricius, 1792) with remarks on biology and economic importance, and larval comparison of co-occurring genera (Coleoptera, Dermestidae).

PubMed

Kadej, Marcin

2018-01-01

Updated descriptions of the last larval instar (based on the larvae and exuviae) and first detailed description of the pupa of Ctesias (s. str.) serra (Fabricius, 1792) (Coleoptera: Dermestidae) are presented. Several morphological characters of C. serra larvae are documented: antenna, epipharynx, mandible, maxilla, ligula, labial palpi, spicisetae, hastisetae, terga, frons, foreleg, and condition of the antecostal suture. The paper is fully illustrated and includes some important additions to extend notes for this species available in the references. Summarised data about biology, economic importance, and distribution of C. serra are also provided. The comparison of larval characteristics for some of the genera of Dermestidae co-occurring with Ctesias is presented. A key for identification of these genera is also provided.

Biological control of livestock pests : Parasitoids

USDA-ARS?s Scientific Manuscript database

House flies, Musca domestica L., and stable flies, Stomoxys calcitrans (L.), are common pests on livestock, poultry, and equine facilities. Biological control of filth flies with pupal parasitoids can be used in conjunction with other control methods as part of an integrated fly management program. ...

Investigation of heavy metals release from sediment with bioturbation/bioirrigation.

PubMed

He, Yi; Men, Bin; Yang, Xiaofang; Li, Yaxuan; Xu, Hui; Wang, Dongsheng

2017-10-01

Bioturbation/bioirrigation can affect the remobilization of metals from sediments. In this study, experiments were performed to examine the effect of bioturbation/bioirrigation by different organisms on cadmium (Cd), copper (Cu), zinc (Zn) and lead (Pb) releasing from the spiked sediment. The diffusive gradient in thin films technique (DGT) revealed that at the end of exposure time, the labile heavy metals concentrations in the pore water for all metal and organisms combinations except Cu and chironomid larvae were much lower than that in the control group. However, the concentrations of heavy metals detected by the DGT were virtually indistinguishable among the treatments with tubificid, chironomid larvae and loach. The correlation analysis of heavy metals with iron (Fe) and manganese (Mn) suggested that Cd, Zn and Pb were most likely bound as Fe-Mn oxidation form in the pore water, but Cu was in other forms. After 28 d of exposure, bioturbation/bioirrigation produced a significant release of particulate heavy metals into the overlying water, especially in the treatment with loach. The bioturbation/bioirrigation impact on the Pb remobilization was less than the other three heavy metals. The effects of bioturbaiton/bioirrigation on the heavy metals remobilization in the sediment were complex that with studying the heavy metals remobilization in the sediment and water interface, the biological indicators should be recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

Late Quaternary paleoclimate of western Alaska inferred from fossil chironomids and its relation to vegetation histories

USGS Publications Warehouse

Kurek, Joshua; Cwynar, Les C.; Ager, Thomas A.; Abbott, Mark B.; Edwards, Mary E.

2009-01-01

Fossil Chironomidae assemblages (with a few Chaoboridae and Ceratopogonidae) from Zagoskin and Burial Lakes in western Alaska provide quantitative reconstructions of mean July air temperatures for periods of the late-middle Wisconsin (~39,000-34,000 cal yr B.P.) to the present. Inferred temperatures are compared with previously analyzed pollen data from each site summarized here by indirect ordination. Paleotemperature trends reveal substantial differences in the timing of climatic warming following the late Wisconsin at each site, although chronological uncertainty exists. Zagoskin Lake shows early warming beginning at about 21,000 cal yr B.P., whereas warming at Burial Lake begins ~4000 years later. Summer climates during the last glacial maximum (LGM) were on average ~3.5C° below the modern temperatures at each site. Major shifts in vegetation occurred from ~19,000 to 10,000 cal yr B.P. at Zagoskin Lake and from ~17,000 to 10,000 cal yr B.P. at Burial Lake. Vegetation shifts followed climatic warming, when temperatures neared modern values. Both sites provide evidence of an early postglacial thermal maximum at ~12,300 cal yr B.P. These chironomid records, combined with other insect-based climatic reconstructions from Beringia, indicate that during the LGM: (1) greater continentality likely influenced regions adjacent to the Bering Land Bridge and (2) summer climates were, at times, not dominated by severe cold.

A model to understand the confounding effects of natural sediments in toxicity tests with Chironomus riparius.

PubMed

Péry, Alexandre R; Sulmon, Vanessa; Mons, Raphaël; Flammarion, Patrick; Lagadic, Laurent; Garric, Jeanne

2003-10-01

Recently, we built a model to link feeding input with growth, emergence, and reproduction of the midge Chironomus riparius exposed to an artificial sandy sediment. This model is based on assumptions about both feeding behavior and use of energy. Here, we show how it can be used for toxicity tests with natural sediments to understand and model the influence of sediment characteristics. We measured growth, emergence, and reproduction of chironomids exposed in beakers to four unpolluted natural sediments and three feeding conditions (no feeding, 0.2 mg Tetramin/larva/d, and 1.4 mg Tetramin/larva/d) and compared the results with data obtained on our artificial sandy sediment. Sediment characteristics had lower influence on growth than feeding level, but their influence could not be neglected. First, we could distinguish between sandy sediments and other sediments. This difference resulted in a significant delay of about 18 h in the growth curves. Second, in case of food limitation, chironomids could use the organic materials in the sediment, provided that the C:N ratio of the sediment was less than 14. Our model proved to be able to incorporate those two phenomena. As for reproduction, we observed a better reproduction (measured in number of eggs per mass) for natural sediments than for artificial sediments. We showed that this difference could be due to the lipid content of the natural sediments.

Coexistence of Fish Species in a Large Lowland River: Food Niche Partitioning between Small-Sized Percids, Cyprinids and Sticklebacks in Submersed Macrophytes

PubMed Central

Dukowska, Małgorzata; Grzybkowska, Maria

2014-01-01

In the spring and summer of each year, large patches of submersed aquatic macrophytes overgrow the bottom of the alluvial Warta River downstream of a large dam reservoir owing to water management practices. Environmental variables, macroinvertebrates (zoobenthos and epiphytic fauna, zooplankton) and fish abundance and biomass were assessed at this biologically productive habitat to learn intraseasonal dynamics of food types, and their occurrence in the gut contents of small-sized roach, dace, perch, ruffe and three-spined stickleback. Gut fullness coefficient, niche breadth and niche overlap indicated how the fishes coexist in the macrophytes. Chironomidae dominated in the diet of the percids. However, ruffe consumed mostly benthic chironomids, while perch epiphytic chironomids and zooplankton. The diet of dace resembled that in fast flowing water although this rheophilic species occurred at unusual density there. The generalist roach displayed the lowest gut fullness coefficient values and widest niche breadth; consequently, intraspecific rather than interspecific competition decided the fate of roach. Three-spined stickleback differed from the other fishes by consuming epiphytic simuliids and fish eggs. The diet overlap between fishes reaching higher gut fullness coefficient values was rather low when the food associated with the submersed aquatic macrophytes was most abundant; this is congruent with the niche overlap hypothesis that maximal tolerable niche overlap can be higher in less intensely competitive conditions. PMID:25365420

Variation in responses to spawning Pacific salmon among three south-eastern Alaska streams

USGS Publications Warehouse

Chaloner, D.T.; Lamberti, G.A.; Merritt, R.W.; Mitchell, N.L.; Ostrom, P.H.; Wipfli, M.S.

2004-01-01

1. Pacific salmon are thought to stimulate the productivity of the fresh waters in which they spawn by fertilising them with marine-derived nutrients (MDN). We compared the influence of salmon spawners on surface streamwater chemistry and benthic biota among three southeastern Alaska streams. Within each stream, reaches up- and downstream of barriers to salmon migration were sampled during or soon after spawners entered the streams. 2. Within streams, concentrations of dissolved ammonium and soluble reactive phosphorus (SRP), abundance of epilithon (chlorophyll a and ash-free dry mass) and biomass of chironomids were significantly higher in reaches with salmon spawners. In contrast, biomass of the mayflies Epeorus spp. and Rhithrogena spp. was significantly higher in reaches lacking spawners. 3. Among streams, significant differences were found in concentrations of dissolved ammonium, dissolved organic carbon, nitrate and SRP, abundance of epilithon, and the biomass of chironomids and Rhithrogena. These differences did not appear to reflect differences among streams in spawner density, nor the changes in water chemistry resulting from salmon spawners. 4. Our results suggest that the 'enrichment' effect of salmon spawners (e.g. increased streamwater nutrient concentrations) was balanced by other concurrent effects of spawners on streams (e.g. sediment disturbance). Furthermore, the collective effect of spawners on lotic ecosystems is likely to be constrained by conditions unique to individual streams, such as temperature, background water chemistry and light attenuation.

Feeding ecology of lake whitefish larvae in eastern Lake Ontario

USGS Publications Warehouse

Johnson, James H.; McKenna, James E.; Chalupnicki, Marc A.; Wallbridge, Tim; Chiavelli, Rich

2009-01-01

We examined the feeding ecology of larval lake whitefish (Coregonus clupeaformis) in Chaumont Bay, Lake Ontario, during April and May 2004-2006. Larvae were collected with towed ichthyoplankton nets offshore and with larval seines along the shoreline. Larval feeding periodicity was examined from collections made at 4-h intervals over one 24-h period in 2005. Inter-annual variation in diet composition (% dry weight) was low, as was spatial variation among collection sites within the bay. Copepods (81.4%), primarily cyclopoids (59.1%), were the primary prey of larvae over the 3-year period. Cladocerans (8.1%; mainly daphnids, 6.7%) and chironomids (7.3%) were the other major prey consumed. Larvae did not exhibit a preference for any specific prey taxa. Food consumption of lake whitefish larvae was significantly lower at night (i.e., 2400 and 0400 h). Substantial variation in diet composition occurred over the 24-h diel study. For the 24-h period, copepods were the major prey consumed (50.4%) and their contribution in the diet ranged from 29.3% (0400 h) to 85.9% (1200 h). Chironomids made up 33.4% of the diel diet, ranging from 8.0% (0800 h) to 69.9% (0400 h). Diel variation in the diet composition of lake whitefish larvae may require samples taken at several intervals over a 24-h period to gain adequate representation of their feeding ecology.

Development of A-type allatostatin immunoreactivity in antennal lobe neurons of the sphinx moth Manduca sexta.

PubMed

Utz, Sandra; Schachtner, Joachim

2005-04-01

The antennal lobe (AL) of the sphinx moth Manduca sexta is a well-established model system for studying mechanisms of neuronal development. To understand whether neuropeptides are suited to playing a role during AL development, we have studied the cellular localization and temporal expression pattern of neuropeptides of the A-type allatostatin family. Based on morphology and developmental appearance, we distinguished four types of AST-A-immunoreactive cell types. The majority of the cells were local interneurons of the AL (type Ia) which acquired AST-A immunostaining in a complex pattern consisting of three rising (RI-RIII) and two declining phases (DI, DII). Type Ib neurons consisted of two local neurons with large cell bodies not appearing before 7/8 days after pupal ecdysis (P7/P8). Types II and III neurons accounted for single centrifugal neurons, with type II neurons present in the larva and disappearing in the early pupa. The type III neuron did not appear before P7/P8. RI and RII coincided with the rises of the ecdysteroid hemolymph titer. Artificially shifting the pupal 20-hydroxyecdysone (20E) peak to an earlier developmental time point resulted in the precocious appearance of AST-A immunostaining in types Ia, Ib, and III neurons. This result supports the hypothesis that the pupal rise in 20E plays a role in AST-A expression during AL development. Because of their early appearance in newly forming glomeruli, AST-A-immunoreactive fibers could be involved in glomerulus formation. Diffuse AST-A labeling during early AL development is discussed as a possible signal providing information for ingrowing olfactory receptor neurons.

Identification of Drosophila melanogaster yellow-f and yellow-f2 proteins as dopachrome-conversion enzymes.

PubMed Central

Han, Qian; Fang, Jianmin; Ding, Haizhen; Johnson, Jody K; Christensen, Bruce M; Li, Jianyong

2002-01-01

This study describes the identification of Drosophila yellow-f and yellow-f2 as dopachrome-conversion enzymes responsible for catalysing the conversion of dopachrome into 5,6-dihydroxyindole in the melanization pathway. Drosophila yellow -y gene and yellow -b, -c, -f and -f2 genes were expressed in an insect cell/baculovirus expression system and their corresponding recombinant proteins were screened for dopachrome-conversion enzyme activity. Among the yellow and yellow -related genes, the yellow -f and yellow -f2 genes were identified as the genes coding for Drosophila dopachrome-conversion enzyme based on the high activity of their recombinant proteins in catalysing the production of 5,6-dihydroxyindole from dopachrome. Both yellow-f and yellow-f2 are capable of mediating a decarboxylative structural rearrangement of dopachrome, as well as an isomerization/tautomerization of dopamine chrome and dopa methyl ester chrome. Northern hybridization revealed the transcription of yellow -f in larvae and pupae, but a high abundance of mRNA was observed in later larval and early pupal stages. In contrast, yellow-f2 transcripts were present at all stages, but high abundance of its mRNA was observed in later-stage pupae and adults. These data indicate that yellow-f and yellow-f2 complement each other during Drosophila development and that the yellow-f is involved in larval and pupal melanization, and yellow-f2 plays a major role in melanization reactions in Drosophila during later pupal and adult development. Results from this study provide the groundwork towards a better understanding of the physiological roles of the Drosophila yellow gene family. PMID:12164780

[Effects of pomegranate varieties on the development and fecundity of Assara inouei Yamanaka (Lepidoptera: Pyralidae)].

PubMed

He, Chao; Shen, Deng Rong; Yin, Li Hong; Li, Xi Liang; He, Jian Cai; Yuan, Sheng Yong; Tian, Xue Jun

2017-03-18

Assara inouei Yanmanaka is an important pest of pomegranate fruits in Yunnan Province. To examine the effects of different pomegranate varieties on the development and reproduction of A. inouei, the biological characteristics, such as the developmental duration, the survival rate and reproduction of this pest feeding on five pomegranate varieties including Tianlvzi, Houpitianshazi, Tianguangyan, Suanlvzi and Suanshazi were observed respectively, and the life table parameters were established under the laboratory conditions of (25±1) ℃, RH (70±10)% and a photoperiod of 15 L:9 D. The results showed that there were no significant differences in the egg stage, larval stage, pupal stage, the longevity of male adults, generation duration form egg to adult and egg hatch rate among the five varieties. There were significant differences in the pre-pupal stage, the longevity of female adults, larval survival, pupation, eclosion and total survival rates, the number of eggs laid per female as well as male and female pupal mass among the five varieties, and all of which except the larval survival were higher on Suanlvzi, followed by Houpitianshazi, but there was no significant difference between these two varieties. The results of life table showed the net reproduction rate, the intrinsic rate of increase and finite rate of increase of the Suanlvzi population were the highest. There were no significant differences in the mean generation time among the five varieties, but significant difference was observed in the population doubling time, which was the shortest on Suanlvzi population. The development and reproduction of A. inouei were better on the Suanlvzi and Houpitianshazi among the five varieties.

[Estimation of Aedes aegypti (L.) (Diptera: Culicidae) productivity in households and public spaces in a dengue endemic city in Colombia].

PubMed

Alcalá, Lucas; Quintero, Juliana; González-Uribe, Catalina; Brochero, Helena

2015-01-01

Aedes aegypti is a vector for the dengue virus in Colombia. Its productivity can be estimated using pupal counts. To determine Ae. aegypti productivity in households and public spaces in Girardot (Colombia) during both wet and dry seasons. The amount of Ae. aegypti pupae was evaluated in 20 randomly selected clusters in Girardot, each consisting of 100 households and public spaces. Inspections were performed during the rainy (February-May, 2011), and dry (August-September, 2011) seasons. House, container, Breteau, person and hectare pupae indices were estimated. During the rainy season households contributed 94% to the total number of pupae (n=7,098) while only 6% (n=482) were found in public spaces. In the dry season, 98% (n=9,138) of pupae were found in households and 2% (n=223), in public spaces. Low water-storage tanks and tanks for washing purposes provided >87% of pupae in households, whereas jars, tires and sinks contained most pupae in public spaces. High pupal densities were observed in public spaces during the rainy season and in streets and schools in the dry season. There were no significant differences in the index per person (rainy season=1.0; dry season=1.3) or per hectare (rainy season=0.96, dry season=0.45) between seasons. High Ae. aegypti pupal densities were found inside households in low water-storage tanks and tanks for washing purposes during both the dry and rainy seasons. Public spaces provided more aquatic habitats during the rainy season. Vector control strategies targeting these containers could allow a more rational use of resources and increase efficiency.

Ecological links between water storage behaviors and Aedes aegypti production: implications for dengue vector control in variable climates.

PubMed

Padmanabha, H; Soto, E; Mosquera, M; Lord, C C; Lounibos, L P

2010-08-01

Understanding linkages between household behavior and Aedes aegypti (L.) larval ecology is essential for community-based dengue mitigation. Here we associate water storage behaviors with the rate of A. aegypti pupal production in three dengue-endemic Colombian cities with different mean temperatures. Qualitative, semi-structured interviews and pupal counts were conducted over a 7-15-day period in 235 households containing a water storage vessel infested with larvae. Emptying vessels more often than every 7 days strongly reduced pupal production in all three cities. Emptying every 7-15 days reduced production by a similar magnitude as emptying <7 days in Armenia (21.9 degrees C), has a threefold smaller reduction as compared to <7 days in Bucaramanga (23.9 degrees C), and did not reduce production in Barranquilla (29.0 degrees C). Lidding vessels reduced mosquito production and was most feasible in Barranquilla because of container structure. Vessel emptying strongly correlated with usage in Barranquilla, where many households stored water in case of interruptions in piped service rather than for regular use. In the cooler cities, >90% of households regularly used stored water for washing clothes, generating a weaker correlation between emptying and usage. Emptying was less frequent in the households surveyed in the dry season in all three cities. These results show that A. aegypti production and human behaviors are coupled in a temperature-dependent manner. In addition to biological effects on aquatic stages, climate change may impact A. aegypti production through human behavioral adaptations. Vector control programs should account for geographic variation in temperature and water usage behaviors in designing targeted interventions.

Effects of inbreeding and temperature stress on life history and immune function in a butterfly.

PubMed

Franke, K; Fischer, K

2013-03-01

Theory predicts that inbreeding depression should be more pronounced under environmental stress due to an increase in the expression of recessive deleterious alleles. If so, inbred populations may be especially vulnerable to environmental change. Against this background, we here investigate effects of inbreeding, temperature stress and its interactions with inbreeding in the tropical butterfly Bicyclus anynana. We use a full-factorial design with three levels of inbreeding (F = 0/0.25/0.38) and three temperature treatments (2 h exposure to 1, 27 or 39 °C). Despite using relatively low levels of inbreeding significant inbreeding depression was found in pupal mass, pupal time, thorax mass, abdomen fat content, egg hatching success and fecundity. However, stress resistance traits (heat tolerance, immune function) were not affected by inbreeding and interactions with temperature treatments were virtually absent. We thus found no support for an increased sensitivity of inbred individuals to environmental stress, and suspect that such patterns are restricted to harsher conditions. Our temperature treatments evidently imposed stress, significantly reducing longevity, fecundity, egg hatching success and haemocyte numbers, while fat content, protein content and lysozyme activity remained unaffected. Males and females differed in all traits measured except pupal time, protein content and phenoloxidase (PO) activity. Correlation analyses revealed, among others, a trade-off between PO and lysozyme activity, and negative correlations between fat content and several other traits. We stress that more data are needed on the effects of inbreeding, temperature variation and sexual differences on insect immune function before more general conclusions can be drawn. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

Water Level Flux in Household Containers in Vietnam - A Key Determinant of Aedes aegypti Population Dynamics

PubMed Central

Jeffery, Jason A. L.; Clements, Archie C. A.; Nguyen, Yen Thi; Nguyen, Le Hoang; Tran, Son Hai; Le, Nghia Trung; Vu, Nam Sinh; Ryan, Peter A.; Kay, Brian H.

2012-01-01

We examined changes in the abundance of immature Aedes aegypti at the household and water storage container level during the dry-season (June-July, 2008) in Tri Nguyen village, central Vietnam. We conducted quantitative immature mosquito surveys of 171 containers in the same 41 households, with replacement of samples, every two days during a 29-day period. We developed multi-level mixed effects regression models to investigate container and household variability in pupal abundance. The percentage of houses that were positive for I/II instars, III/IV instars and pupae during any one survey ranged from 19.5–43.9%, 48.8–75.6% and 17.1–53.7%, respectively. The mean numbers of Ae. aegypti pupae per house ranged between 1.9–12.6 over the study period. Estimates of absolute pupal abundance were highly variable over the 29-day period despite relatively stable weather conditions. Most variability in pupal abundance occurred at the container rather than the household level. A key determinant of Ae. aegypti production was the frequent filling of the containers with water, which caused asynchronous hatching of Ae. aegypti eggs and development of cohorts of immatures. We calculated the probability of the water volume of a large container (>500L) increasing or decreasing by ≥20% to be 0.05 and 0.07 per day, respectively, and for small containers (<500L) to be 0.11 and 0.13 per day, respectively. These human water-management behaviors are important determinants of Ae. aegypti production during the dry season. This has implications for choosing a suitable Wolbachia strain for release as it appears that prolonged egg desiccation does not occur in this village. PMID:22911683

The Occurrence of the Holometabolous Pupal Stage Requires the Interaction between E93, Krüppel-Homolog 1 and Broad-Complex

PubMed Central

Ureña, Enric; Chafino, Silvia; Manjón, Cristina; Franch-Marro, Xavier; Martín, David

2016-01-01

Complete metamorphosis (Holometaboly) is a key innovation that underlies the spectacular success of holometabolous insects. Phylogenetic analyses indicate that Holometabola form a monophyletic group that evolved from ancestors exhibiting hemimetabolous development (Hemimetaboly). However, the nature of the changes underlying this crucial transition, including the occurrence of the holometabolan-specific pupal stage, is poorly understood. Using the holometabolous beetle Tribolium castaneum as a model insect, here we show that the transient up-regulation of the anti-metamorphic Krüppel-homolog 1 (TcKr-h1) gene at the end of the last larval instar is critical in the formation of the pupa. We find that depletion of this specific TcKr-h1 peak leads to the precocious up-regulation of the adult-specifier factor TcE93 and, hence, to a direct transformation of the larva into the adult form, bypassing the pupal stage. Moreover, we also find that the TcKr-h1-dependent repression of TcE93 is critical to allow the strong up-regulation of Broad-complex (TcBr-C), a key transcription factor that regulates the correct formation of the pupa in holometabolous insects. Notably, we show that the genetic interaction between Kr-h1 and E93 is also present in the penultimate nymphal instar of the hemimetabolous insect Blattella germanica, suggesting that the evolution of the pupa has been facilitated by the co-option of regulatory mechanisms present in hemimetabolan metamorphosis. Our findings, therefore, contribute to the molecular understanding of insect metamorphosis, and indicate the evolutionary conservation of the genetic circuitry that controls hemimetabolan and holometabolan metamorphosis, thereby shedding light on the evolution of complete metamorphosis. PMID:27135810

No impact of transgenic nptII-leafy Pinus radiata (Pinales: Pinaceae) on Pseudocoremia suavis (Lepidoptera: Geometridae) or its endoparasitoid Meteorus pulchricornis (Hymenoptera: Braconidae).

PubMed

Burgess, E P J; Barraclough, E I; Kean, A M; Walter, C; Malone, L A

2011-10-01

To investigate the biosafety to insects of transgenic Pinus radiata D. Don containing the antibiotic resistance marker gene nptII and the reproductive control gene leafy, bioassays were conducted with an endemic lepidopteran pest of New Zealand plantation pine forests and a hymenopteran endoparasitoid. Larvae of the common forest looper, Pseudocoremia suavis (Butler), were fed from hatching on P. radiata needles from either one of two nptII-leafy transgenic clones, or an isogenic unmodified control line. For both unparasitized P. suavis and those parasitized by Meteorus pulchricornis (Wesmael), consuming transgenic versus control pine had no impact on larval growth rate or mass at any age, larval duration, survival, pupation or successful emergence as an adult. Total larval duration was 1 d (3%) longer in larvae fed nptII-2 than nptII-1, but this difference was considered trivial and neither differed from the control. In unparasitized P. suavis larvae, pine type consumed did not affect rate of pupation or adult emergence, pupal mass, or pupal duration. Pine type had no effect on the duration or survival of M. pulchricornis larval or pupal stages, mass of cocoons, stage at which they died, adult emergence, or fecundity. Parasitism by M. pulchricornis reduced P. suavis larval growth rate, increased the duration of the third larval stadium, and resulted in the death of all host larvae before pupation. The lack of impact of an exclusive diet of nptII-leafy transgenic pines on the life history of P. suavis and M. pulchricornis suggests that transgenic plantation pines expressing nptII are unlikely to affect insect populations in the field.

Effects of MON810 Bt field corn on adult emergence of Helicoverpa zea (Lepidoptera: Noctuidae).

PubMed

Horner, T A; Dively, G P; Herbert, D A

2003-06-01

A 3-yr study (1996-1998) was conducted to evaluate the effects of MON810 Bt corn on Helicoverpa zea (Boddie) emergence and to determine whether delayed larval development as a result of Bt intoxication results in higher levels of diapause induction and pupal mortality. In the 1997 study, there was no difference in prepupal mortality between corn types, although significantly more prepupae from Bt plots than from non-Bt plots died in emergence buckets before constructing pupal chambers in 1998. In all years, significantly fewer moths emerged from prepupae collected from Bt plots, suggesting that effects of the expressed Cry1Ab extended to the prepupal and pupal stages. Late plantings of corn showed the greatest reductions in moth emergence from Bt corn because environmental conditions were more conducive to trigger diapause at the time H. zea was developing in these plantings. This was supported by a significantly greater proportion of diapausing pupae remaining in the ground in the late plantings of both Bt and non-Bt corn. For April and early May plantings, larval feeding on Bt corn delayed the time to pupation, although there was no significant difference in moth emergence between corn types for those larvae that successfully pupated. Although Bt expression had less impact on the proportion of moths emerging, the actual number of moths emerging from Bt corn was significantly reduced because fewer larvae reached pupation. Delays in adult emergence, along with significant reductions in adult emergence from MON810 Bt corn, should reduce the rates of colonization in soybean and other late host crops but may also result in asynchrony of mating between individuals emerging from Bt and non-Bt corn. This, in turn, may contribute to the evolution of resistance to Bt corn.

Quantifying the harmful potential of ten essential oils on immature Trichogramma pretiosum stages.

PubMed

Parreira, Douglas Silva; Alcántara-de la Cruz, Ricardo; Leite, Germano Leão Demolin; Ramalho, Francisco de Souza; Zanuncio, José Cola; Serrão, José Eduardo

2018-05-01

The use of chemical insecticides and non-selective natural products authorized for use in organic farming may reduce the effectiveness of egg parasitoids. The side-effects of ten plant essential oils on immature stages of Trichogramma pretiosum were evaluated. Carapa guianensis, Origanum vulgare and Zingiber officinalle during the F 1 generation, and Azadirachtin and Mentha piperita in the F 2 generation were slightly harmful (class II: 30-79%) to the emergence of this parasitoid. All essential oils affected the longevity of females of the F 1 and F 2 generations. Thymus vulgaris and Z. officinalle were the oils most harmful to female longevity. Carapa guianensis proved slightly harmful (class II: 30-79%) to parasitism in the F 1 generation when applied during the egg-larval and pre-pupal stages and O. vulgare in the F 1 generation in the pre-pupal stage alone, of this parasitoid. The sex ratio was lower than 0.5 during the pre-pupal stage of the F 1 generation with Azadirachtin, C. guianensis, O. vulgare, Piper nigrum and Syzigium aromaticum, but this parameter was not affected for the other biological stages of T. pretiosum in the F 1 and F 2 generations. The Azadirachtin, C. guianensis, M. piperita, O. vulgare, T. vulgaris and Z. officinalle oils revealed a mild toxic effect to the immature stages of T. pretiosum and, therefore, it should be used according to patterns of ecological selectivity. Allium sativum and Citrus sinensis essential oils were not harmful to T. pretiosum, and can be used in Integrated Pest Management. Copyright © 2018 Elsevier Ltd. All rights reserved.

Targeting a Hidden Enemy: Pyriproxyfen Autodissemination Strategy for the Control of the Container Mosquito Aedes albopictus in Cryptic Habitats

PubMed Central

Suman, Devi Shankar; Wang, Yi; Unlu, Isik; Williges, Eric; Williams, Gregory M.; Gaugler, Randy

2016-01-01

Background The Asian tiger mosquito, Aedes albopictus, is a vector of dengue, Chikungunya, and Zika viruses. This mosquito inhabits a wide range of artificial water-holding containers in urban and suburban areas making it difficult to control. We tested the hypothesis that female-driven autodissemination of an insect growth regulator could penetrate cryptic oviposition habitats difficult to treat with conventional insecticidal sprays. Methodology Oviposition preferences of Ae. albopictus females for open and cryptic cups were tested in semi-field experiments. Two conventional larvicidal sprayers were tested to determine droplet penetration and larvicidal efficacy in open and cryptic habitats using Bacillus thuringiensis var. israelensis (Bti) in the field. Finally, the efficacy of pyriproxyfen autodissemination stations was assessed in cryptic and open cups in residential areas during 2013 and 2014. Principal Findings Gravid females strongly preferred cryptic (53.1±12.9 eggs/cup) over open (10.3±4.3 eggs/cup) cups for oviposition. Cryptic cups showed limited droplet penetration and produced 0.1–0.3% larval mortality with a conventional backpack and low-volume sprays of Bti. The autodissemination stations effectively contaminated these cryptic cups (59.3–84.6%) and produced 29.7–40.8% pupal mortality during 2013–2014. Significant pupal mortality was also observed in open cups. Conclusions The autodissemination station effectively exploits the oviposition behavior of wild gravid females to deliver pyriproxyfen to targeted oviposition habitats. Although the pupal mortality in cryptic cups was relatively lower than expected for the effective vector control. Autodissemination approach may be a suitable supporting tool to manage Ae. albopictus immatures in the cryptic habitats those are less accessible to conventional larvicidal sprays. PMID:28033379

Inhibition of the growth and development of mosquito larvae of Culex quinquefasciatus (Diptera: Culicidae) treated with extract from leaves of Pseudocalymma alliaceum (Bignonaceae).

PubMed

Granados-Echegoyen, Carlos; Pérez-Pacheco, Rafael; Soto-Hernández, Marcos; Ruiz-Vega, Jaime; Lagunez-Rivera, Luicita; Alonso-Hernandez, Nancy; Gato-Armas, Rene

2014-08-01

To determine larvicidal activity of the essential oil, hydrolat and botanical extracts derived from leaves of Pseudocalymma alliaceum on mosquito larvae of Culex quinquefasciatus. Groups of twenty larvae were used in the larvicidal assays. The mortality, relative growth rate, the larval and pupal duration and viability was estimated. The essential oil was analyzed by solid phase microextraction using gas chromatography coupled to mass spectrometry. Essential oil at 800 ppm showed larvicidal activity at 24 h with lethal values of LC50 and LC90 of 267.33 and 493.63 ppm. The hydrolat at 20% and 10% on 2nd stage larvae showed 100% effectiveness after 24 h. The aqueous extract at 10% had a relative growth index of 0.58, while the ethanolic and methanolic extract obtained values of 0.76 and 0.70 and control reached 0.99. Larvae treated with 10% of methanol, ethanol and aqueous extract showed a reduction in larval duration of 5.00, 2.20 and 4.35 days; ethanol extract at 1% provoke decrease of 2.40 days in the development and exhibited an increment of 3.30 days when treated with 0.01%. Aqueous, ethanol and methanol extracts at 10% reduced in 6.15, 3.42 and 5.57 days pupal development. The main compounds were diallyl disulfide (50.05%), diallyl sulfide (11.77%) and trisulfide di-2-propenyl (10.37%). The study demonstrated for the first time, the larvicidal activity of the essential oil and hydrolat of Pseudocalymma alliaceum; aqueous, ethanol and methanol extracts inhibited the normal growth and development of mosquito larvae, prolonging and delaying larval and pupal duration. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Suppression of Laccase 2 severely impairs cuticle tanning and pathogen resistance during the pupal metamorphosis of Anopheles sinensis (Diptera: Culicidae).

PubMed

Du, Ming-Hui; Yan, Zheng-Wen; Hao, You-Jin; Yan, Zhen-Tian; Si, Feng-Ling; Chen, Bin; Qiao, Liang

2017-04-04

Phenol oxidases (POs) catalyze the oxidation of dopa and dopamine to melanin, which is crucial for cuticle formation and innate immune maintenance in insects. Although, Laccase 2, a member of the PO family, has been reported to be a requirement for melanin-mediated cuticle tanning in the development stages of some insects, whether it participates in cuticle construction and other physiological processes during the metamorphosis of mosquito pupae is unclear. The association between the phenotype and the expression profile of Anopheles sinensis Laccase 2 (AsLac2) was assessed from pupation to adult eclosion. Individuals showing an expression deficiency of AsLac2 that was produced by RNAi and their phenotypic defects and physiological characterizations were compared in detail with the controls. During the dominant expression period, knockdown of AsLac2 in pupae caused the cuticle to be unpigmented, and produced thin and very soft cuticles, which further impeded the eclosion rate of adults as well as their fitness. Moreover, melanization immune responses in the pupae were sharply decreased, leading to poor resistance to microorganism infection. Both the high conservation among Laccase 2 homologs and a very similar genomic synteny of the neighborhood in Anopheles genus implies a conservative function in the pupal stage. To our knowledge, this is the first study to report the serious phenotypic defects in mosquito pupae caused by the dysfunction of Laccase 2. Our findings strongly suggest that Laccase 2 is crucial for Anopheles cuticle construction and melanization immune responses to pathogen infections during pupal metamorphosis. This irreplaceability provides valuable information on the application of Lacccase 2 and/or other key genes in the melanin metabolism pathway for developing mosquito control strategies.

Spruce budworm weight and fecundity: means, frequency distributions, and correlations for two populations (Lepidoptera: tortricidae)

Treesearch

Nancy Lorimer; Leah S. Bauer

1983-01-01

Pupal weights and fecundities of spruce budworm from Minnesota had different means, coefficients of variation, and frequency distributions than spruce budworm from New Hampshire. The two variables were correlated in one of the populations but not the other.

Thermal performance of two indigenous pupal parasitoids attacking the invasive Drosophila suzukii (Diptera: Drosophilidae)

USDA-ARS?s Scientific Manuscript database

Pachycrepoideus vindemiae (Rondani) and Trichopria drosophilae (Perkins) are among a few indigenous parasitoids attacking the invasive Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) in North America. Both parasitoid species occur in California, whereas only P. vindemiae has been reported fr...

Competition between the filth fly parasitoids Muscidifurax raptor and M. raptorellus (Hymenoptera: Pteromalidae)

USDA-ARS?s Scientific Manuscript database

Competition bioassays were conducted with the filth fly pupal parasitoids Muscidurax raptor (Girault & Sanders) and M. raptorellus (Kogan & Legner) (Hymenoptera: Pteromalidae) with house fly Musca domestica L. (Diptera: Muscidae) hosts at different host densities. Assays were conducted by varying e...

Interplay of cell dynamics and epithelial tension during morphogenesis of the Drosophila pupal wing

PubMed Central

Etournay, Raphaël; Popović, Marko; Merkel, Matthias; Nandi, Amitabha; Blasse, Corinna; Aigouy, Benoît; Brandl, Holger; Myers, Gene; Salbreux, Guillaume; Jülicher, Frank; Eaton, Suzanne

2015-01-01

How tissue shape emerges from the collective mechanical properties and behavior of individual cells is not understood. We combine experiment and theory to study this problem in the developing wing epithelium of Drosophila. At pupal stages, the wing-hinge contraction contributes to anisotropic tissue flows that reshape the wing blade. Here, we quantitatively account for this wing-blade shape change on the basis of cell divisions, cell rearrangements and cell shape changes. We show that cells both generate and respond to epithelial stresses during this process, and that the nature of this interplay specifies the pattern of junctional network remodeling that changes wing shape. We show that patterned constraints exerted on the tissue by the extracellular matrix are key to force the tissue into the right shape. We present a continuum mechanical model that quantitatively describes the relationship between epithelial stresses and cell dynamics, and how their interplay reshapes the wing. DOI: http://dx.doi.org/10.7554/eLife.07090.001 PMID:26102528

Host suitability of Phaseolus lunata for Trichoplusia ni (lepidoptera: noctuidae) in controlled carbon dioxide atmospheres

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

Osbrink, W.L.A.; Trumble, J.T.; Wagner, R.E.

1987-06-01

Elevated atmospheric carbon dioxide (CO/sub 2/) levels of 1000 parts per million (ppm) significantly increased consumption of foliage by Trichoplusia ni (Huebner) and significantly enhanced growth of Phaseolus lunata L. when compared with ambient levels of 340 ppm. Mean pupal weight was less under treatments with elevated atmospheric CO/sub 2/ under a high fertilization regime, but larval survival and percent nitrogen content of pupae were not affected by level of CO/sub 2/ treatments at high, medium, or low fertilizer rates. Regardless of CO/sub 2/ concentration, larval survival and pupal weight were reduced in absence of fertilizer. Nitrogen and protein consumptionmore » increased with fertilization rate. Because percent leaf area of plants consumed by T. ni larvae was not affected by CO/sub 2/ concentration, this study suggests that increased plant growth resulting from elevated atmospheric CO/sub 2/ may benefit the plant proportionately more than the insect.« less

Exogenous JH and ecdysteroid applications alter initiation of polydnaviral replication in an endoparasitoid wasp, Cotesia plutellae (Braconidae: Hymenoptera).

PubMed

Park, Bokri; Kim, Yonggyun

2011-06-01

Polydnaviruses are a group of double-stranded DNA viruses and are symbiotically associated with some ichneumonoid wasps. As proviruses, the replication of polydnaviruses occurs in the female reproductive organ at the pupal stage. This study analyzed the effects of two developmental hormones, juvenile hormone (JH) and ecdysteroid, on the viral replication of Cotesia plutellae bracovirus (CpBV). All 23 CpBV segments identified contained a conserved excision/rejoining site ('AGCTTT') from their proviral segments. Using quantitative real-time PCR based on this excision/rejoining site marker, initiation of CpBV replication was determined to have occurred on day 4 on the pupal stage. Pyriproxyfen, a JH agonist, significantly inhibited adult emergence of C. plutellae, whereas RH5992, an ecdysteroid agonist, had no inhibitory effect. Although RH5992 had no effect dose on adult development, it significantly accelerated viral replication. The results of immunoblotting assays against viral coat proteins support the effects of the hormone agonists on viral replication.

Reproductive potential of Spodoptera eridania (Stoll) (Lepidoptera: Noctuidae) in the laboratory: effect of multiple couples and the size.

PubMed

Specht, A; Montezano, D G; Sosa-Gómez, D R; Paula-Moraes, S V; Roque-Specht, V F; Barros, N M

2016-06-01

This study aimed to evaluate the effect of keeping three couples in the same cage, and the size of adults emerged from small, medium-sized and large pupae (278.67 mg; 333.20 mg and 381.58 mg, respectively), on the reproductive potential of S. eridania (Stoll, 1782) adults, under controlled conditions (25 ± 1 °C, 70% RH and 14 hour photophase). We evaluated the survival, number of copulations, fecundity and fertility of the adult females. The survival of females from these different pupal sizes did not differ statistically, but the survival of males from large pupae was statistically shorter than from small pupae. Fecundity differed significantly and correlated positively with size. The number of effective copulations (espematophores) and fertility did not vary significantly with pupal size. Our results emphasize the importance of indicating the number of copulations and the size of the insects when reproductive parameters are compared.

A whole genome screening and RNA interference identify a juvenile hormone esterase-like gene of the diamondback moth, Plutella xylostella.

PubMed

Gu, Xiaojun; Kumar, Sunil; Kim, Eunjin; Kim, Yonggyun

2015-09-01

Juvenile hormone (JH) plays a crucial role in preventing precocious metamorphosis and stimulating reproduction. Thus, its hemolymph titer should be under a tight control. As a negative controller, juvenile hormone esterase (JHE) performs a rapid breakdown of residual JH in the hemolymph during last instar to induce a larval-to-pupal metamorphosis. A whole genome of the diamondback moth (DBM), Plutella xylostella, has been annotated and proposed 11 JHE candidates. Sequence analysis using conserved motifs commonly found in other JHEs proposed a putative JHE (Px004817). Px004817 (64.61 kDa, pI=5.28) exhibited a characteristic JHE expression pattern by showing high peak at the early last instar, at which JHE enzyme activity was also at a maximal level. RNA interference of Px004817 reduced JHE activity and interrupted pupal development with a significant increase of larval period. This study identifies Px004817 as a JHE-like gene of P. xylostella. Copyright © 2015 Elsevier Ltd. All rights reserved.

Irradiation for quarantine control of the invasive light brown apple moth, Epiphyas

USDA-ARS?s Scientific Manuscript database

The effects of irradiation on egg, larval, and pupal development, and adult reproduction in light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), were examined. Eggs, neonates, early instars, late instars, early pupae and late pupae were irradiated at target doses of 60, ...

Bed Bug Detection: Current Technologies and Future Directions

PubMed Central

Vaidyanathan, Rajeev; Feldlaufer, Mark F.

2013-01-01

Technologies to detect bed bugs have not kept pace with their global resurgence. Early detection is critical to prevent infestations from spreading. Detection based exclusively on bites is inadequate, because reactions to insect bites are non-specific and often misdiagnosed. Visual inspections are commonly used and depend on identifying live bugs, exuviae, or fecal droplets. Visual inspections are inexpensive, but they are time-consuming and unreliable when only a few bugs are present. Use of a dog to detect bed bugs is gaining in popularity, but it can be expensive, may unintentionally advertise a bed bug problem, and is not foolproof. Passive monitors mimic natural harborages; they are discreet and typically use an adhesive to trap bugs. Active monitors generate carbon dioxide, heat, a pheromone, or a combination to attract bed bugs to a trap. New technologies using DNA analysis, mass spectrometry, and electronic noses are innovative but impractical and expensive for widespread use. PMID:23553226

Effect of exposure time on mass-rearing production of the olive fruit fly parasitoid, Psyttalia lounsburyi (Hymenoptera: Braconidae)

USDA-ARS?s Scientific Manuscript database

Classical biological control programs rely on mass-production of high quality beneficial insects for subsequent releases into the field. Psyttalia lounsburyi (Silvestri) (Hymenoptera: Braconidae) is a koinobiont larval-pupal endoparasitoid of tephritid flies that is being reared to support a classic...

Inhibition of eicosanoid signaling leads to increased lipid peroxidation in a host/parasitoid system

USDA-ARS?s Scientific Manuscript database

We posed the hypothesis that eicosanoids act in reduction of oxidative stress in insects. Here we report that inhibiting eicosanoid biosynthesis throughout the larval, pupal and adult life led to major alterations on some oxidative and antioxidative parameters of the greater wax moth, Galleria mello...

Suitability of a liquid larval diet for rearing the Philippines fruit fly Bactrocera philippinensis (Diptera:Tephritidae)

USDA-ARS?s Scientific Manuscript database

A liquid larval diet as an artificial rearing medium was successfully tested for the Philippines fruit fly Bactrocera philippinensis Drew & Hancock. The biological parameters studied were pupal weight, adult emergence and fliers, sex ratio, fecundity and fertility. The insects performed most satisfa...

Toxicity and physiological effect of quercetin on generalist herbivore, Spodoptera litura Fab. and a non-target earthworm Eisenia fetida Savigny

USDA-ARS?s Scientific Manuscript database

A novel flavonoid, quercetin, was isolated from Euphorbia hirta L., a medicinal plant using chromatography techniques including: Thin-layer chromatography, Column chromatography, Nuclear magnetic resonance spectroscopy. Toxicity to larval of Spodoptera litura analyze pupal weight, survival rate, fec...

Mortality and reproductive effects of ingested spinosad on adult bollworm

USDA-ARS?s Scientific Manuscript database

Bollworm adults (Lepidoptera: Noctuidae) upon emergence from their pupal cells actively seek and feed on plant exudates before they disperse and reproduce on suitable host plants. This nocturnal behavior of the bollworm may be exploited as a pest management strategy for suppression of the insect. Th...

Parasitoids of the Southern Pine Beetle

Treesearch

C. Wayne Berisford

2011-01-01

Hymenopterous parasitoids make up a significant portion of the natural enemy complex associated with the southern pine beetle (SPB). Collectively, parasitoids can affect the growth of individual SPB infestations and area populations by reducing the survival rates of developing SPB larval/pupal broods. A substantial body of information on parasitoids has been...

Persistence of two Salmonella enterica ser. Montevideo strains throughout horn fly (Diptera: Muscidae) larval and pupal development

USDA-ARS?s Scientific Manuscript database

Strains of Salmonella enterica can be subdivided into clades that differ in their composition of genes, including those that influence microbial ecology and bacterial transmission. Salmonella serovar Montevideo strains 1110 and 304, representatives of two different clades, were used throughout this ...

The direct and indirect effects of a glyphosate-based herbicide and nutrients on Chironomidae (Diptera) emerging from small wetlands.

PubMed

Baker, Leanne F; Mudge, Joseph F; Houlahan, Jeff E; Thompson, Dean G; Kidd, Karen A

2014-09-01

Laboratory and mesocosm experiments have demonstrated that some glyphosate-based herbicides can have negative effects on benthic invertebrate species. Although these herbicides are among the most widely used in agriculture, there have been few multiple-stressor, natural system-based investigations of the impacts of glyphosate-based herbicides in combination with fertilizers on the emergence patterns of chironomids from wetlands. Using a replicated, split-wetland experiment, the authors examined the effects of 2 nominal concentrations (2.88 mg acid equivalents/L and 0.21 mg acid equivalents/L) of the glyphosate herbicide Roundup WeatherMax, alone or in combination with nutrient additions, on the emergence of Chironomidae (Diptera) before and after herbicide-induced damage to macrophytes. There were no direct effects of treatment on the structure of the Chironomidae community or on the overall emergence rates. However, after macrophyte cover declined as a result of herbicide application, there were statistically significant increases in emergence in all but the highest herbicide treatment, which had also received no nutrients. There was a negative relationship between chironomid abundance and macrophyte cover on the treated sides of wetlands. Fertilizer application did not appear to compound the effects of the herbicide treatments. Although direct toxicity of Roundup WeatherMax was not apparent, the authors observed longer-term impacts, suggesting that the indirect effects of this herbicide deserve more consideration when assessing the ecological risk of using herbicides in proximity to wetlands. © 2014 SETAC.

Late Quaternary paleoclimate of western Alaska inferred from fossil chironomids and its relation to vegetation histories

NASA Astrophysics Data System (ADS)

Kurek, Joshua; Cwynar, Les C.; Ager, Thomas A.; Abbott, Mark B.; Edwards, Mary E.

2009-05-01

Fossil Chironomidae assemblages (with a few Chaoboridae and Ceratopogonidae) from Zagoskin and Burial Lakes in western Alaska provide quantitative reconstructions of mean July air temperatures for periods of the late-middle Wisconsin (˜39,000-34,000 cal yr B.P.) to the present. Inferred temperatures are compared with previously analyzed pollen data from each site summarized here by indirect ordination. Paleotemperature trends reveal substantial differences in the timing of climatic warming following the late Wisconsin at each site, although chronological uncertainty exists. Zagoskin Lake shows early warming beginning at about 21,000 cal yr B.P., whereas warming at Burial Lake begins ˜4000 years later. Summer climates during the last glacial maximum (LGM) were on average ˜3.5 °C below the modern temperatures at each site. Major shifts in vegetation occurred from ˜19,000 to 10,000 cal yr B.P. at Zagoskin Lake and from ˜17,000 to 10,000 cal yr B.P. at Burial Lake. Vegetation shifts followed climatic warming, when temperatures neared modern values. Both sites provide evidence of an early postglacial thermal maximum at ˜12,300 cal yr B.P. These chironomid records, combined with other insect-based climatic reconstructions from Beringia, indicate that during the LGM: (1) greater continentality likely influenced regions adjacent to the Bering Land Bridge and (2) summer climates were, at times, not dominated by severe cold.

Chironomidae bloodworms larvae as aquatic amphibian food.

PubMed

Fard, Mojdeh Sharifian; Pasmans, Frank; Adriaensen, Connie; Laing, Gijs Du; Janssens, Geert Paul Jules; Martel, An

2014-01-01

Different species of chironomids larvae (Diptera: Chironomidae) so-called bloodworms are widely distributed in the sediments of all types of freshwater habitats and considered as an important food source for amphibians. In our study, three species of Chironomidae (Baeotendipes noctivagus, Benthalia dissidens, and Chironomus riparius) were identified in 23 samples of larvae from Belgium, Poland, Russia, and Ukraine provided by a distributor in Belgium. We evaluated the suitability of these samples as amphibian food based on four different aspects: the likelihood of amphibian pathogens spreading, risk of heavy metal accumulation in amphibians, nutritive value, and risk of spreading of zoonotic bacteria (Salmonella, Campylobacter, and ESBL producing Enterobacteriaceae). We found neither zoonotic bacteria nor the amphibian pathogens Ranavirus and Batrachochytrium dendrobatidis in these samples. Our data showed that among the five heavy metals tested (Hg, Cu, Cd, Pb, and Zn), the excess level of Pb in two samples and low content of Zn in four samples implicated potential risk of Pb accumulation and Zn inadequacy. Proximate nutritional analysis revealed that, chironomidae larvae are consistently high in protein but more variable in lipid content. Accordingly, variations in the lipid: protein ratio can affect the amount and pathway of energy supply to the amphibians. Our study indicated although environmentally-collected chironomids larvae may not be vectors of specific pathogens, they can be associated with nutritional imbalances and may also result in Pb bioaccumulation and Zn inadequacy in amphibians. Chironomidae larvae may thus not be recommended as single diet item for amphibians. © 2014 Wiley Periodicals, Inc.

Spider-mediated flux of PCBs from contaminated sediments to terrestrial ecosystems and potential risks to arachnivorous birds

USGS Publications Warehouse

Walters, D.M.; Mills, M.A.; Fritz, K.M.; Raikow, D.F.

2010-01-01

We investigated aquatic insect utilization and PCB exposure in riparian spiders at the Lake Hartwell Superfund site (Clemson, SC). We sampled sediments, adult chironomids, terrestrial insects, riparian spiders (Tetragnathidae, Araneidae, and Mecynogea lemniscata), and upland spiders (Araneidae) along a sediment contamination gradient. Stable isotopes (?13C, ? 15N) indicated that riparian spiders primarily consumed aquatic insects whereas upland spiders consumed terrestrial insects. PCBs in chironomids (mean 1240 ng/g among sites) were 2 orders of magnitude higher than terrestrial insects (15.2 ng/g), similar to differences between riparian (820?2012 ng/g) and upland spiders (30 ng/g). Riparian spider PCBs were positively correlated with sediment concentrations for all taxa (r2 = 0.44?0.87). We calculated spider-based wildlife values (WVs, the minimum spider PCB concentrations causing physiologically significant doses in consumers) to assess exposure risks for arachnivorous birds. Spider concentrations exceeded WVs for most birds at heavily contaminated sites and were ?14-fold higher for the most sensitive species (chickadee nestlings, Poecile spp.). Spiders are abundant and ubiquitous in riparian habitats, where they depend on aquatic insect prey. These traits, along with the high degree of spatial correlation between spider and sediment concentrations we observed, suggest that they are model indicator species for monitoring contaminated sediment sites and assessing risks associated with contaminant flux into terrestrial ecosystems. ?? This article not subject to U.S. Copyright. Published 2009 by the American Chemical Society.

Sinks and sources: Assessing microplastic abundance in river sediment and deposit feeders in an Austral temperate urban river system.

PubMed

Nel, Holly A; Dalu, Tatenda; Wasserman, Ryan J

2018-01-15

Microplastics are important novel pollutants in freshwaters but their behaviour in river sediments is poorly understood due to the large amounts of coloured dissolved organic matter that impede sample processing. The present study aimed to 1.) estimate the microplastic pollution dynamics in an urban river system experiencing temporal differences in river flow, and 2.) investigate the potential use of chironomids as indicators of microplastic pollution levels in degraded freshwater environments. Microplastic levels were estimated from sediment and Chironomus spp. larvae collected from various sites along the Bloukrans River system, in the Eastern Cape South Africa during the summer and winter season. River flow, water depth, channel width, substrate embeddedness and sediment organic matter were simultaneously collected from each site. The winter season was characterised by elevated microplastic abundances, likely as a result of lower energy and increased sediment deposition associated with reduced river flow. In addition, results showed that particle distribution may be governed by various other external factors, such as substrate type and sediment organic matter. The study further highlighted that deposit feeders associated with the benthic river habitats, namely Chironomus spp. ingest microplastics and that the seasonal differences in sediment microplastic dynamics were reflected in chironomid microplastic abundance. There was a positive, though weakly significant relationship between deposit feeders and sediment suggesting that deposit feeders such as Chironomus spp. larvae could serve as an important indicator of microplastic loads within freshwater ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

Diet, feeding patterns, and prey selection of subyearling Atlantic salmon (Salmo salar) and subyearling chinook salmon (Oncorhynchus tshawytscha) in a tributary of Lake Ontario

USGS Publications Warehouse

Johnson, J. H.; Nash, K. J.; Chiavelli, R. A.; DiRado, J. A.; Mackey, G. E.; Knight, J. R.; Diaz, A. R.

2017-01-01

Since juvenile Atlantic salmon (Salmo salar) and Chinook salmon (Oncorhynchus tshawytscha) occupy a similar habitat in Lake Ontario tributaries, we sought to determine the degree of diet similarity between these species in order to assess the potential for interspecific competition. Atlantic salmon, an historically important but currently extirpated component of the Lake Ontario fish community, are the focus of a bi-national restoration effort. Presently this effort includes the release of hatchery produced juvenile Atlantic salmon in Lake Ontario tributaries. These same tributaries support substantial numbers of naturally reproduced juvenile Pacific salmonids including Chinook salmon. Subyearling Atlantic salmon and subyearling Chinook salmon had significantly different diets during each of the three time periods examined. Atlantic salmon fed slightly more from the benthos than from the drift and consumed mainly chirononmids (47.0%) and ephemeropterans (21.1%). The diet of subyearling Chinook salmon was more closely associated with the drift and consisted mainly of chironomids (60.2%) and terrestrial invertebrates (16.0%). Low diet similarity between subyearling Atlantic salmon and subyearling Chinook salmon likely minimizes competitive interactions for food between these species in Lake Ontario tributaries. However, the availability of small prey such as chironomids which comprise over 50% of the diet of each species, soon after emergence, could constitute a short term resource limitation. To our knowledge this is the first study of interspecific diet associations between these two important salmonid species.

Rock glacier outflows may adversely affect lakes: lessons from the past and present of two neighboring water bodies in a crystalline-rock watershed.

PubMed

Ilyashuk, Boris P; Ilyashuk, Elena A; Psenner, Roland; Tessadri, Richard; Koinig, Karin A

2014-06-03

Despite the fact that rock glaciers are one of the most common geomorphological expressions of mountain permafrost, the impacts of their solute fluxes on lakes still remain largely obscure. We examined water and sediment chemistry, and biota of two neighboring water bodies with and without a rock glacier in their catchments in the European Alps. Paleolimnological techniques were applied to track long-term temporal trends in the ecotoxicological state of the water bodies and to establish their baseline conditions. We show that the active rock glacier in the mineralized catchment of Lake Rasass (RAS) represents a potent source of acid rock drainage that results in enormous concentrations of metals in water, sediment, and biota of RAS. The incidence of morphological abnormalities in the RAS population of Pseudodiamesa nivosa, a chironomid midge, is as high as that recorded in chironomid populations inhabiting sites heavily contaminated by trace metals of anthropogenic origin. The incidence of morphological deformities in P. nivosa of ∼70% persisted in RAS during the last 2.5 millennia and was ∼40% in the early Holocene. The formation of RAS at the toe of the rock glacier most probably began at the onset of acidic drainage in the freshly deglaciated area. The present adverse conditions are not unprecedented in the lake's history and cannot be associated exclusively with enhanced thawing of the rock glacier in recent years.

Seasonal Variation, Export Dynamics and Consumption of Freshwater Invertebrates in an Estuarine Environment

NASA Astrophysics Data System (ADS)

Williams, D. D.; Williams, N. E.

1998-03-01

In the Aber Estuary, North Wales, significant numbers of freshwater benthic invertebrates occurred in the tidal freshwater area. Distinct seasonal patterns were observed in their longitudinal zonation which appeared to be unrelated to variations in tidal inundation. The December extension downstream of freshwater taxa is hypothesized to be in response to decreasing water temperatures. In April, larvae/nymphs of the Trichoptera (caddisflies), Ephemeroptera (mayflies) and Plecoptera (stoneflies) ranged as far as a site inundated by 80·9% of all high tides, and larval Elmidae and Chironomidae (midges) occurred at the most marine site (inundated twice daily by all high tides). In July, with the exception of the Chironomidae, the range of most aquatic insects had contracted to the upper estuary. Although, in general, densities of aquatic insects decreased towards the lower estuary, significant densities persisted there. For example, maxima of 3514 chironomid larvae and 48 caddisfly larvae m -2were recorded at the 80·9% inundation site. An estimated 31×10 6freshwater invertebrates (weighing 62·6 kg), per annum, passed from fresh water into salt water across any given transect along the estuary. In comparison, the annual influx of invertebrates carried upstream by incoming tides was estimated to be 1·9×10 6(6·2%; weighing 2·5 kg). Predominant in the downstream drift were the larvae/nymphs and/or pupae of chironomids, mayflies, stoneflies and caddisflies. The ' reverse ' drift comprised mainly copepods, ostracods, amphipods and oligochaetes. Mites and the brackishwater amphipod Gammarus zaddachicommonly moved in both directions. Highest drift densities occurred in July, whereas the lowest densities occurred in late autumn and winter. Multiple regression analysis showed no relationship between total drift or ' reverse ' drift densities and any of the measured environmental variables. Many of the freshwater invertebrates appeared not to die upon passing into tidal sections but resumed a benthic existence by virtue of varying degrees of salt tolerance. Of the three fish species common in the estuary, eel, common goby and flounder, the last two preyed measurably on freshwater taxa. Whereas gobies tended to be opportunistic feeders, depending on the section of estuary that they occupied, flounder were more restricted to the upper estuary where they fed selectively on chironomid larvae. On the latter diet, between March and September, the mean wet weight of flounders increased by more than 100 times (from 5 to 540 mg). Gobies were more numerous in the estuary from September to February, and although they ate insects their primary prey was G. zaddachi.

Effects of temperature on Anoplophora glabripennis (Coleoptera: Cerambycidae) larvae and pupae

Treesearch

M.A. Keena; P.M. Moore

2010-01-01

Developmental thresholds, degree-days for development, larval weights, and head capsule widths for each larval instar and the pupal stage of Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae) were studied at eight constant temperatures (5, 10, 15, 20, 25, 30, 35, and 40ºC) for two source populations (Ravenswood, Chicago, IL [...

Pupation behavior and larval and pupal biocontrol of Drosophila suzukii in the field

USDA-ARS?s Scientific Manuscript database

Drosophila suzukii is a worldwide pest of fruit crops. Biological control may play an important role in D. suzukii IPM, and suppressing populations in unmanaged areas. While predation has been observed in the field, nothing is known about the potential for natural enemies to reduce D. suzukii popula...

A Florida defoliator found: Nystalea ebalea (Lepidoptera: Notodontidae) feeding on Brazilian peppertree

USDA-ARS?s Scientific Manuscript database

A species of Notodontidae, Nystalea ebalea was discovered feeding on leaflets of the invasive weed Schinus terebinthifolius in south Florida. The larvae of this species have generally 5 instars and require 20-22 d to reach the pupal stage. Discovery of wild populations of this Neotropical species in...

Performance of gypsy moth larvae on hosts from the Deep South: survival, development and host preferences

Treesearch

C. Wayne Berisford; Todd J. Lanigan; Michael E. Montgomery

1991-01-01

Survival, development time and pupal weights of gypsy moth, Lymantria dispar L., which had fed on southern tree hosts were determined. Five species of oaks, Quercus spp.; sweetgum, Liquidambar styracflua L.; and river birch, Betula nigra L., were found to be acceptable hosts. Survival and...

Description of immature stages of Scymnus (Neopullus) sinuanodulus Yu and Yao (Coleoptera: Coccinellidae) with notes on life history

Treesearch

Wenhua Lu; Phetsamon Souphanya; Michael E. Montgomery

2002-01-01

We describe for the first time immature stages of the Scymnus subgenus Neopullus; namely the egg, larval (4 instars), and pupal stages of Scymnus (Neopullus) sinuanodulus Yu and Yao (Coleoptera: Coccinellidae), which is indigenous to China. This lady beetle was imported to...

Attraction of the bark beetle parasitoid Roptrocerus xylophagorum (Hymenoptera: Pteromalidae) to host-associated olfactory cues

Treesearch

Brian T. Sullivan; Eva M. Pettersson; Katja C. Seltmann; C. Wayne Berisford

2000-01-01

Studies were conducted to identify host location cues used by Roptrocerus xylophagorum (Ratzeburg), a larval/pupal parasitoid of bark beetles. In Y-tube olfactometer bioassays, female R. xylophagorum were attracted to infested bark (i.e., phloem, cambium, and outer corky bark tissues) removed from bolts of loblolly pine,...

Postharvest irradiation treatment for quarantine control of the invasive Lobesia botrana (Lepidoptera: Tortricidae)

USDA-ARS?s Scientific Manuscript database

The effects of irradiation on egg, larval, and pupal development in European grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae), were examined. Eggs, neonates, third instars, fifth instars, and early and late stage pupae were irradiated at target doses of 50, 100, 150, or 200 Gy or left untr...

Micro-computed tomography of pupal metamorphosis in the solitary bee Megachile rotundata

USDA-ARS?s Scientific Manuscript database

Insect metamorphosis involves a complex change in form and function, but most of these changes are internal and treated as a black box. In this study, we examined development of the solitary bee, Megachile rotundata, using micro-computed tomography (µCT) and digital volume analysis. We describe deve...

Pupal deposition and ecology of bat flies (Diptera: Streblidae): Trichobius sp. (caecus group) in a Mexican cave habitat.

PubMed

Dittmar, Katharina; Dick, Carl W; Patterson, Bruce D; Whiting, Michael F; Gruwell, Matthew E

2009-04-01

We studied the deposition of pupae of the winged bat fly Trichobius sp. (caecus group; Diptera), an ectoparasite of Natalus stramineus (Chiroptera, Natalidae), in a natural cave in Tamaulipas, Mexico. For the first time, we show a strong spatial segregation of populations of a streblid bat fly at different stages of development. Using molecular techniques we were able to match developmental stages to adults. Only 5 pupae were present in the main bat roosts. The overwhelming majority occurred exclusively in the bat flyway passages at a considerable distance from roosting bats. Pupal density corresponded positively with the average flight height of bats in the cave passage. Taken together, observations suggest that these ectoparasites must actively seek out their hosts by moving onto passing or roosting bats. The scarceness of pupae in the main roost may be dictated by environmental constraints for their development. The estimated population of viable pupae far exceeds the population of imagoes on the bats, and predation on adults by spiders is common.

Deceptive vibratory communication: pupae of a beetle exploit the freeze response of larvae to protect themselves.

PubMed

Kojima, Wataru; Ishikawa, Yukio; Takanashi, Takuma

2012-10-23

It is argued that animal signals may have evolved so as to manipulate the response of receivers in a way that increases the fitness of the signallers. In deceptive communication, receivers incur costs by responding to false signals. Recently, we reported that pupae of the soil-inhabiting Japanese rhinoceros beetle Trypoxylus dichotoma produce vibratory signals to deter burrowing larvae, thereby protecting themselves. In the present study, monitoring of vibrations associated with larval movement revealed that T. dichotoma larvae remained motionless for ca 10 min when pupal vibratory signals were played back transiently (freeze response). Furthermore, pupal signals of T. dichotoma elicited a freeze response in three other scarabaeid species, whose pupae do not produce vibratory signals. This indicates that the freeze response to certain types of vibration evolved before the divergence of these species and has been evolutionarily conserved, presumably because of the fitness advantage in avoiding predators. Pupae of T. dichotoma have probably exploited pre-existing anti-predator responses of conspecific larvae to protect themselves by emitting deceptive vibratory signals.

Temperature-dependent Development of Parasarcophaga similis (Meade 1876) and its Significance in Estimating Postmortem Interval.

PubMed

Yang, Lijun; Wang, Yu; Li, Liangliang; Wang, Jiangfeng; Wang, Min; Zhang, Yingna; Chu, Jun; Liu, Kun; Hou, Yiding; Tao, Luyang

2017-09-01

Flesh flies are commonly found insects on decaying corpses that appears slightly later than blowflies, and their development patterns are significant indicators for minimum postmortem interval (PMI min ) estimation. In this study, the flesh fly Parasarcophaga similis (Meade 1876) was reared at nine constant temperatures ranging from 15°C to 35°C to examine indicators for estimating their age. We generated three development models, including isomorphen diagram, isomegalen diagram, and thermal summation model. Larval body length at different rearing temperatures was fit into an L = a + bT + cT 2 + dT 3 equation with which the relationship between the larval body length (L) and the time after larviposition (T) was confirmed. The pupal stage was categorized into 13 substages according to intrapuparial morphological changes, and a detailed table was generated of the pupal developmental stages at five rearing temperatures, 15°C, 20°C, 25°C, 30°C, and 35°C. This study provides fundamental data in supporting P. similis as an indicator for PMI min estimation. © 2017 American Academy of Forensic Sciences.

Functional characterization of the vitellogenin promoter in the silkworm, Bombyx mori.

PubMed

Xu, J; Wang, Y Q; Li, Z Q; Ling, L; Zeng, B S; You, L; Chen, Y Z; Aslam, A F M; Huang, Y P; Tan, A J

2014-10-01

Genetic transformation and genome editing technologies have been successfully established in the lepidopteran insect model, the domesticated silkworm, Bombyx mori, providing great potential for functional genomics and practical applications. However, the current lack of cis-regulatory elements in B. mori gene manipulation research limits further exploitation in functional gene analysis. In the present study, we characterized a B. mori endogenous promoter, Bmvgp, which is a 798-bp DNA sequence adjacent to the 5'-end of the vitellogenin gene (Bmvg). PiggyBac-based transgenic analysis shows that Bmvgp precisely directs expression of a reporter gene, enhanced green fluorescent protein (EGFP), in a sex-, tissue- and stage-specific manner. In transgenic animals, EGFP expression can be detected in the female fat body from larval-pupal ecdysis to the following pupal and adult stage. Furthermore, in vitro and in vivo experiments revealed that EGFP expression can be activated by 20-hydroxyecdysone, which is consistent with endogenous Bmvg expression. These data indicate that Bmvgp is an effective endogenous cis-regulatory element in B. mori. © 2014 The Royal Entomological Society.

Phytoextract-induced developmental deformities in malaria vector.

PubMed

Sharma, Preeti; Mohan, Lalit; Srivastava, C N

2006-09-01

Larvicidal potential of petroleum ether (Pee), carbon tetrachloride (Cte) and methanol extract (Mee) of Artemisia annua, Chenopodium album and Sonchus oleraceus was observed against malaria vector, Anopheles stephensi Liston. The Pee of A. annua with LC50 16.85 ppm after 24 h and 11.45 ppm after 48 h of treatment was found most effective, followed by Cte of A. annua and Ch. album, Pee of Ch. album and Mee of A. annua. However, no significant larvicidal activity was observed in Mee of Ch. album and all the three extracts of S. oleraceous. The Pee of A. annua was further investigated for its effect on the metamorphosis and the development of the malaria vector. It influenced the early life cycle of An. stephensi by reducing the percentage of hatching, larval, pupal and adult emergence and also lengthening the larval and pupal periods. The growth index was also reduced significantly. As the extract has remarkable effect on the metamorphosis and high larvicidal potential, it could, therefore, be used as an effective biocontrol agent against the highly nuisant malaria vector.

EcR expression in the prothoracicotropic hormone-producing neurosecretory cells of the Bombyx mori brain.

PubMed

Hossain, Monwar; Shimizu, Sakiko; Fujiwara, Haruhiko; Sakurai, Sho; Iwami, Masafumi

2006-08-01

The steroid hormone 20-hydroxyecdysone (20E) initiates insect molting and metamorphosis through binding with a heterodimer of two nuclear receptors, the ecdysone receptor (EcR) and ultraspiracle (USP). Expression of the specific isoforms EcR-A and EcR-B1 governs steroid-induced responses in the developing cells of the silkworm Bombyx mori. Here, analysis of EcR-A and EcR-B1 expression during larval-pupal development showed that both genes were up-regulated by 20E in the B. mori brain. Whole-mount in situ hybridization and immunohistochemistry revealed that EcR-A and EcR-B1 mRNAs and proteins were exclusively located in two pairs of lateral neurosecretory cells in the larval brain known as the prothoracicotropic hormone (PTTH)- producing cells (PTPCs). In the pupal brain, EcR-A and EcR-B1 expression was detected in tritocerebral cells and optic lobe cells in addition to PTPCs. As PTTH controls ecdysone secretion by the prothoracic gland, these results indicate that 20E-responsive PTPCs are the master cells of insect metamorphosis.

Microwave-assisted extraction of silkworm pupal oil and evaluation of its fatty acid composition, physicochemical properties and antioxidant activities.

PubMed

Hu, Bin; Li, Cheng; Zhang, Zhiqing; Zhao, Qing; Zhu, Yadong; Su, Zhao; Chen, Yizi

2017-09-15

Microwave-assisted extraction (MAE) of oil from silkworm pupae was firstly performed in the present research. The response surface methodology was applied to optimize the parameters for MAE. The yield of oil by MAE was 30.16% under optimal conditions of a mixed solvent consisting of ethanol and n-hexane (1:1, v/v), microwave power (360W), liquid to solid ratio (7.5/1mL/g), microwave time (29min). Moreover, oil extracted by MAE was quantitatively (yield) and qualitatively (fatty acid profile) similar to those obtained using Soxhlet extraction (SE), but oil extracted by MAE exhibited favourable physicochemical properties and oxidation stability. Additionally, oil extracted by MAE had a higher content of total phenolic, and it showed stronger antioxidant activities. Scanning electron microscopy revealed that microwave technique efficiently promoted the release of oil by breaking down the cell structure of silkworm pupae. Therefore, MAE can be an effective method for the silkworm pupal oil extraction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sublethal effects of insecticides used in soybean on the parasitoid Trichogramma pretiosum.

PubMed

de Paiva, Ana Clara Ribeiro; Beloti, Vitor Hugo; Yamamoto, Pedro Takao

2018-05-01

To control crop pests, parasitoid wasps of the genus Trichogramma are one alternative to the use of insecticides. Since a wide variety of agrochemicals may be applied to the same crops, it is essential to assess the selectivity of insecticides used for pest control on Trichogramma pretiosum. Information on which insecticides are less harmful to T. pretiosum can improve biological control using this insect, an important tactic in IPM programs for field crops. This study aimed to determine the effects of insecticides on the pupal stage and on the parasitism capacity of T. pretiosum. Lambda-cyhalothrin + thiamethoxam were slightly harmful and chlorpyriphos was moderately harmful to the pupal stage, while acephate, chlorfenapyr and flubendiamide, although considered innocuous, affected the succeeding generations of wasps, with low emergence of F 1 . Chlorfenapyr, chlorpyriphos and lambda-cyhalothrin + thiamethoxam reduced the parasitism, and acephate had a deleterious effect on the generation that contacted the insecticide residue. For an effective IPM program, it is important to apply selective insecticides. Further studies are needed to determine the selectivity of these insecticides under field conditions.

A contribution to the systematics of Australasian Tanytarsini (Diptera: Chironomidae): first descriptions from New Caledonia.

PubMed

Giłka, Wojciech; Dobosz, Roland

2015-06-26

First specific records of chironomids of the tribe Tanytarsini from New Caledonia based on detailed descriptions of new species are presented. Cladotanytarsus (Cladotanytarsus) stylifer sp. nov. and its closest relatives, i.a. Cladotanytarsus (C.) isigacedeus (Sasa et Suzuki, 2000), comb. nov., known from males bearing extraordinarily elongate hypopygial anal points are diagnosed. Paratanytarsus mirificus sp. nov. is described as adult male with unique structure of its hypopygium and shortened antennae. Diagnostic description of Tanytarsus fuscithorax Skuse, 1889 is also complemented.

Assessing streamflow characteristics as limiting factors on benthic invertebrate assemblages in streams across the western United States

USGS Publications Warehouse

Konrad, C.P.; Brasher, A.M.D.; May, J.T.

2008-01-01

4. Relative abundance of Plecoptera, richness of non-insect taxa and relative abundance of intolerant taxa were associated with multiple streamflow metrics. Metrics of sensitive taxa (Ephemeroptera, Plecoptera and Trichoptera), and intolerant taxa generally had ceilings associated with flow metrics while metrics of tolerant taxa, non-insects, dominance and chironomids generally had floors. Broader characteristics of invertebrate assemblages such as abundance and richness had fewer limits, but these limits were nonetheless associated with a broad range of streamflow characteristics.

Bacterial Larvicide, Bacillus thuringiensis israelensis Strain AM 65-52 Water Dispersible Granule Formulation Impacts Both Dengue Vector, Aedes aegypti (L.) Population Density and Disease Transmission in Cambodia

PubMed Central

Socheat, Doung

2016-01-01

A multi-phased study was conducted in Cambodia from 2005–2011 to measure the impact of larviciding with the bacterial larvicide, Bacillus thuringiensis israelensis (Bti), a water dispersible granule (WG) formulation on the vector, Aedes aegypti (L.) and the epidemiology. In our studies, all in-use containers were treated at 8 g/1000 L, including smaller containers and animal feeders which were found to contribute 23% of Ae aegypti pupae. The treated waters were subjected to routine water exchange activities. Pupal production was suppressed by an average 91% for 8 weeks. Pupal numbers continued to remain significantly lower than the untreated commune (UTC) for 13 weeks post treatment in the peak dengue vector season (p<0.05). Suppression of pupal production was supported by very low adult numbers in the treated commune. An average 70% of the household harbored 0–5 Ae aegypti mosquitoes per home for 8 weeks post treatment, but in the same period of time >50% of the household in the UTC harbored ≥11 mosquitoes per home. The adult population continued to remain at significantly much lower numbers in the Bti treated commune than in the UTC for 10–12 weeks post treatment (p<0.05). In 2011, a pilot operational program was evaluated in Kandal Province, a temephos resistant site. It was concluded that 2 cycles of Bti treatment in the 6 months monsoon season with complete coverage of the target districts achieved an overall dengue case reduction of 48% in the 6 treated districts compared to the previous year, 2010. Five untreated districts in the same province had an overwhelming increase of 352% of dengue cases during the same period of time. The larvicide efficacy, treatment of all in-use containers at the start of the monsoon season, together with treatment coverage of entire districts interrupted disease transmission in the temephos resistant province. PMID:27627758

Ecological Modeling of Aedes aegypti (L.) Pupal Production in Rural Kamphaeng Phet, Thailand

PubMed Central

Aldstadt, Jared; Koenraadt, Constantianus J. M.; Fansiri, Thanyalak; Kijchalao, Udom; Richardson, Jason; Jones, James W.; Scott, Thomas W.

2011-01-01

Background Aedes aegypti (L.) is the primary vector of dengue, the most important arboviral infection globally. Until an effective vaccine is licensed and rigorously administered, Ae. aegypti control remains the principal tool in preventing and curtailing dengue transmission. Accurate predictions of vector populations are required to assess control methods and develop effective population reduction strategies. Ae. aegypti develops primarily in artificial water holding containers. Release recapture studies indicate that most adult Ae. aegypti do not disperse over long distances. We expect, therefore, that containers in an area of high development site density are more likely to be oviposition sites and to be more frequently used as oviposition sites than containers that are relatively isolated from other development sites. After accounting for individual container characteristics, containers more frequently used as oviposition sites are likely to produce adult mosquitoes consistently and at a higher rate. To this point, most studies of Ae. aegypti populations ignore the spatial density of larval development sites. Methodology Pupal surveys were carried out from 2004 to 2007 in rural Kamphaeng Phet, Thailand. In total, 84,840 samples of water holding containers were used to estimate model parameters. Regression modeling was used to assess the effect of larval development site density, access to piped water, and seasonal variation on container productivity. A varying-coefficients model was employed to account for the large differences in productivity between container types. A two-part modeling structure, called a hurdle model, accounts for the large number of zeroes and overdispersion present in pupal population counts. Findings The number of suitable larval development sites and their density in the environment were the primary determinants of the distribution and abundance of Ae. aegypti pupae. The productivity of most container types increased significantly as habitat density increased. An ecological approach, accounting for development site density, is appropriate for predicting Ae. aegypti population levels and developing efficient vector control programs. PMID:21267055

Bacterial Larvicide, Bacillus thuringiensis israelensis Strain AM 65-52 Water Dispersible Granule Formulation Impacts Both Dengue Vector, Aedes aegypti (L.) Population Density and Disease Transmission in Cambodia.

PubMed

Setha, To; Chantha, Ngan; Benjamin, Seleena; Socheat, Doung

2016-09-01

A multi-phased study was conducted in Cambodia from 2005-2011 to measure the impact of larviciding with the bacterial larvicide, Bacillus thuringiensis israelensis (Bti), a water dispersible granule (WG) formulation on the vector, Aedes aegypti (L.) and the epidemiology. In our studies, all in-use containers were treated at 8 g/1000 L, including smaller containers and animal feeders which were found to contribute 23% of Ae aegypti pupae. The treated waters were subjected to routine water exchange activities. Pupal production was suppressed by an average 91% for 8 weeks. Pupal numbers continued to remain significantly lower than the untreated commune (UTC) for 13 weeks post treatment in the peak dengue vector season (p<0.05). Suppression of pupal production was supported by very low adult numbers in the treated commune. An average 70% of the household harbored 0-5 Ae aegypti mosquitoes per home for 8 weeks post treatment, but in the same period of time >50% of the household in the UTC harbored ≥11 mosquitoes per home. The adult population continued to remain at significantly much lower numbers in the Bti treated commune than in the UTC for 10-12 weeks post treatment (p<0.05). In 2011, a pilot operational program was evaluated in Kandal Province, a temephos resistant site. It was concluded that 2 cycles of Bti treatment in the 6 months monsoon season with complete coverage of the target districts achieved an overall dengue case reduction of 48% in the 6 treated districts compared to the previous year, 2010. Five untreated districts in the same province had an overwhelming increase of 352% of dengue cases during the same period of time. The larvicide efficacy, treatment of all in-use containers at the start of the monsoon season, together with treatment coverage of entire districts interrupted disease transmission in the temephos resistant province.

Baculovirus-mediated gene transfer in butterfly wings in vivo: an efficient expression system with an anti-gp64 antibody.

PubMed

Dhungel, Bidur; Ohno, Yoshikazu; Matayoshi, Rie; Otaki, Joji M

2013-03-25

Candidate genes for color pattern formation in butterfly wings have been known based on gene expression patterns since the 1990s, but their functions remain elusive due to a lack of a functional assay. Several methods of transferring and expressing a foreign gene in butterfly wings have been reported, but they have suffered from low success rates or low expression levels. Here, we developed a simple, practical method to efficiently deliver and express a foreign gene using baculovirus-mediated gene transfer in butterfly wings in vivo. A recombinant baculovirus containing a gene for green fluorescent protein (GFP) was injected into pupae of the blue pansy butterfly Junonia orithya (Nymphalidae). GFP fluorescence was detected in the pupal wings and other body parts of the injected individuals three to five days post-injection at various degrees of fluorescence. We obtained a high GFP expression rate at relatively high virus titers, but it was associated with pupal death before color pattern formation in wings. To reduce the high mortality rate caused by the baculovirus treatment, we administered an anti-gp64 antibody, which was raised against baculovirus coat protein gp64, to infected pupae after the baculovirus injection. This treatment greatly reduced the mortality rate of the infected pupae. GFP fluorescence was observed in pupal and adult wings and other body parts of the antibody-treated individuals at various degrees of fluorescence. Importantly, we obtained completely developed wings with a normal color pattern, in which fluorescent signals originated directly from scales or the basal membrane after the removal of scales. GFP fluorescence in wing tissues spatially coincided with anti-GFP antibody staining, confirming that the fluorescent signals originated from the expressed GFP molecules. Our baculovirus-mediated gene transfer system with an anti-gp64 antibody is reasonably efficient, and it can be an invaluable tool to transfer, express, and functionally examine foreign genes in butterfly wings and also in other non-model insect systems.

Assessment of a liquid larval diet for rearing Dacus and Bactrocera species (Diptera:Tephritidae), in Western Africa

USDA-ARS?s Scientific Manuscript database

The fruit fly larval diet formulations developed by USDA-ARS were used in this study to compare with other artificial and natural diet to rear two Dacus species. The evaluation was based on the parameters of egg hatch, pupal production, adult emergence, flight ability, and productivity. This study s...

Development of neuropeptide analogs capable of traversing the integument: A case study using diapause hormone analogs in Helicoverpa zea

USDA-ARS?s Scientific Manuscript database

Diapause hormone and its analogs terminate pupal diapause in H. zea when injected, but if such agents are to be used as effective diapause disruptors it will be essential to develop simple techniques for administering active compounds that can exert their effect by penetrating the insect epidermis. ...

Effect of host decoys on the ability of the parasitoids Muscidifurax raptor and Spalangia cameroni to parasitize house fly (Diptera: Muscidae) puparia

USDA-ARS?s Scientific Manuscript database

The pteromalid pupal parasitoids Muscidifurax raptor Girault and Sanders and Spalangia cameroni Perkins (Hymenoptera: Pteromalidae) are commonly released on livestock farms for management of house flies (Diptera: Muscidae). To be effective, parasitoids must be able to locate live host puparia in co...

Helicopter Propwash Dislodges Few Spruce Budworms

Treesearch

Daniel T. Jennings; Mark W. Houseweart; Mark W. Houseweart

1986-01-01

Propwash treatments from a low-flying Bell 47-G2 helicopter dislodged few spruce budworm larvae and pupae from host balsam-fir trees. After propwash treatments, both larval-pupal densities on branch samples and in drop-tray collections near the ground were not significantly different between treated and control plots. Significantly more larvae were found in the lower...

Pupal abnormalities among laboratory-reared gypsy moths

Treesearch

Richard W. Hansen

1991-01-01

Gypsy moth cohorts from 10 near-wild strains (one to six previous generations in culture), six wild strains (field-collected egg masses), and the standard "New Jersey" lab strain (34th and 35th generation in culture) were reared on Otis wheat germ-based artificial diet, in a constant environment. Rearings were begun with newly-hatched first instars; pupae...

Diapause hormone in the Helicoverpa/Heliothis complex: a review of gene expression, peptide structure and activity, analog and antagonist development, and the receptor

USDA-ARS?s Scientific Manuscript database

This review summarizes recent studies focusing on diapause hormone (DH) in the Helicoverpa/Heliothis complex of agricultural pests. Moths in this complex overwinter in pupal diapause, a form of developmental arrest used to circumvent unfavorable seasons. DH was originally reported in the silkmoth ...

Irrigation and Fertilization Effects on Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Damage Levels and Pupal Weight in an Intensively-Managed Pine Plantation

Treesearch

David R. Coyle; John T. Nowak; Christopher J. Fettig

2003-01-01

The widespread application of intensive forest management practices throughout the southeastern U.S. has increased loblolly pine, pinus taeda L., yields and shortened conventional rotation lengths. Fluctuations in Nantucket pine tip moth, Rhyacionia frustrana (Comstock), population density and subsequent damage levels have been...

Aphanogmus sp. (Hymenoptera: Ceraphronidae): a hyperparasitoid of the coffee berry borer parasitoid Prorops nasuta (Hymenoptera: Bethylidae) in Kenya

USDA-ARS?s Scientific Manuscript database

This is the first report of a hyperparasitod of the primary parasitoid of the coffee berry borer Prorops nasuta Waterston (Hymenoptera: Bethylidae). Aphanogmus sp is a gregarious ectoparasitoid of larval and pupal stages of P. nasuta, which was found in coffee berry samples collected on the ground o...

The Early Stages of Pedaliodes poesia (Hewitson, 1862) in Eastern Ecuador (Lepidoptera: Satyrinae: Pronophilina)

PubMed Central

Greeney, Harold F.; Pyrcz, Tomasz W.; DeVries, Philip J.; Dyer, Lee A.

2009-01-01

We describe the immature stages Pedaliodes poesia Hewitson, 1862 from northeastern Ecuador. Chusquea scandens (Poaceae, Bambusoidea) is the larval food plant. Eggs are laid singly or in pairs on the bottom side of host plant leaves. The duration of the egg, larval, and pupal stages, combined, is 99–107 days. PMID:19619029

Molecular cloning and functional characterization of the diapause hormone receptor in the corn earworm Helicoverpa zea

USDA-ARS?s Scientific Manuscript database

The diapause hormone (DH) in the heliothine moth has shown its activity in termination of pupal diapause, while the orthology in the silkworm is known to induce embryonic diapause. In the current study, we cloned the diapause hormone receptor from the corn earworm Helicoverpa zea (HzDHr) and tested ...

Holocene Climate Reconstructions from Lake Water Oxygen Isotopes in NW and SW Greenland

NASA Astrophysics Data System (ADS)

Lasher, G. E.; Axford, Y.; McFarlin, J. M.; Kelly, M. A.; Osterberg, E. C.; Berkelhammer, M. B.; Berman, K.; Kotecki, P.; Gawin, B.

2016-12-01

Reconstructions of stable isotopes of precipitation (SIP) from currently unglaciated parts of Greenland can help elucidate spatial patterns of past climate shifts in this climatically important and complex region. We have developed a 7700-year record of lake water δ18O from a small non-glacial lake in NW Greenland (near Thule Air Base), inferred from the δ18O of subfossil chironomid (insect) head capsules and aquatic mosses. Lake water δ18O remains constant from 8 ka until 4 ka and then declines by 2.5 ‰ to the present, representing a +2.5 to 5.5 °C Holocene Thermal Maximum temperature anomaly for this region. For comparison, two new sediment records from hydrologically connected lakes south of Nuuk in SW Greenland record 8500 years of lake water δ18O, also inferred from δ18O of chironomids. At the time cores were collected during the summer in 2014 and 2015, all lakes reflected SIP and exhibited minimal evaporation influence. Historical monitoring of stable isotopes of precipitation from Thule Air Base and Grønnedal in south Greenland suggest the controls on SIP differ greatly between our two study sites, as would be predicted based upon the strongly Arctic (in the NW) versus North Atlantic (in the SW) atmospheric and marine influences at the two sites. Interpretation of Holocene climate from these two contrasting sites will be discussed. These climate records from the same proxy allow us to compare millennial scale Holocene climate responses to northern hemisphere solar insolation trends in two different climate regimes of Greenland.

Application of non-lethal stable isotope analysis to assess feeding patterns of juvenile pallid sturgeon Scaphirhynchus albus: a comparison of tissue types and sample preservation methods

USGS Publications Warehouse

Andvik, R.T.; VanDeHey, J.A.; Fincel, M.J.; French, William E.; Bertrand, K.N.; Chipps, Steven R.; Klumb, Robert A.; Graeb, B.D.S.

2010-01-01

Traditional techniques for stable isotope analysis (SIA) generally require sacrificing animals to collect tissue samples; this can be problematic when studying diets of endangered species such as the pallid sturgeon Scaphirhynchus albus. Our objectives were to (i) determine if pectoral fin tissue (non-lethal) could be a substitute for muscle tissue (lethal) in SIA of juvenile pallid sturgeon, and (ii) evaluate the influence of preservation techniques on stable isotope values. In the laboratory, individual juvenile pallid sturgeon were held for up to 186 day and fed chironomids, fish, or a commercially available pellet diet. Significant, positive relationships (r² ≥ 0.8) were observed between fin and muscle tissues for both δ15N and δ13C; in all samples isotopes were enriched in fins compared to muscle tissue. Chironomid and fish based diets of juvenile pallid sturgeon were distinguishable for fast growing fish (0.3 mm day−1) using stable δ15N and δ13C isotopes. Frozen and preserved fin tissue δ15N isotopes were strongly related (r2 = 0.89) but δ13C isotopes were weakly related (r2 = 0.16). Therefore, freezing is recommended for preservation of fin clips to avoid the confounding effect of enrichment by ethanol. This study demonstrates the utility of a non-lethal technique to assess time integrated food habits of juvenile pallid sturgeon and should be applicable to other threatened or endangered species.

Effects of pulse and press drying disturbance on benthic stream communities

USGS Publications Warehouse

Lynch, Dustin T.; Magoulick, Daniel D.

2016-01-01

Natural disturbance is an integral component of most ecosystems and occurs in 3 different forms: pulse, press, and ramp. In lotic ecosystems, seasonal drought is a major form of disturbance, particularly in intermittent headwater streams, which often are reduced to pools that serve as refuges for biota. We used simulated intermittent stream pools to compare the effects of control, pulse, and press drying on growth and survival in 3 fish species (Lepomis megalotis, Campostoma anomalum, and Etheostoma spectabile) commonly found together in drought-prone streams in the Ozark Highlands, USA. We also compared effects on benthic community structure, including periphyton and chironomid density and sediment in deep (permanently watered) and shallow (intermittently dewatered) habitat. Only one species, L. megalotis, showed a significant reduction in length and mass growth in press drying compared with control treatments. Drying and type of drying had no effect on survival of any fish species. Drying and type of drying had strong overall effects on periphyton growth in shallow habitats, where ash-free dry mass decreased and the autotrophic index (the ratio of chlorophyll a to total biomass) increased significantly in drying relative to control and in press relative to pulse treatments. Drying negatively affected sediment accumulation in shallow habitat and chironomid density in deep habitat. Drying in intermittent streams has species-dependent effects on fish growth and benthic structure, and pulse and press drying differ in their effects on periphyton in these systems. These effects may have important consequences in seasonally drying streams as anthropogenic influence on stream drying increases.

Environmental conditions and biotic interactions influence ecosystem structure and function in a drying stream

USGS Publications Warehouse

Ludlam, J.P.; Magoulick, D.D.

2010-01-01

Benthic consumers influence stream ecosystem structure and function, but these interactions depend on environmental context. We experimentally quantified the effects of central stoneroller minnows (Campostoma anomalum (Rafinesque) and Meek's crayfish (Orconectes meeki meeki (Faxon)) on benthic communities using electric exclusion quadrats in Little Mulberry Creek before (June) and during (August) seasonal stream drying. Unglazed ceramic tiles were deployed in June and August to measure periphyton and invertebrate abundance, and leafpack decomposition and primary production were also measured in August. Relationships between stoneroller and crayfish density and the size of consumer effects were evaluated with multiple linear regression models. Average chlorophyll a abundance was greater on exposed than exclusion tiles in August, but not in June. Sediment dry mass, periphyton ash-free dry mass (AFDM), and chironomid densities on tiles did not differ among treatments in either period. Leaf packs decayed faster in exposed than exclusion treatments (kexposed = 0.038 ?? 0.013, kexclusion = 0.007 ?? 0.002), but consumer effects were stronger in some pools than others. Leafpack invertebrate biomass and abundance and tile primary productivity did not differ among treatments. Consumer effects on chlorophyll a were related to crayfish and stoneroller density, and effects on chironomid density were related to stoneroller density. These results contrast with a previous exclusion experiment in Little Mulberry Creek that demonstrated strong consumer effects. The influence of stream drying on consumer effects appears to have been reduced by strong spates, underscoring the importance of conducting multi-year studies to determine the magnitude of variability in ecological interactions. ?? US Government: USGS 2010.

Teratogenic and genotoxic responses of larval Chironomus (Diptera) to contaminated sediments

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

Hudson, L.A.; Muir, K.; Ciborowski, J.J.H.

1994-12-31

Sediment-associated contaminants can produce developmental or genotoxic stresses independently of their cytotoxic effects. In the laboratory, the authors exposed Chironomus larvae to mixtures of polluted (either Detroit R., MI, or cadmium or benzo-[a]-pyrene-spiked) sediment diluted with uncontaminated, formulated sediment. Second-instar Chironomus nr. salinarius were grown to 4th star in water filled 1-L jars containing 300 mL of contaminated:formulated sediment mixture in ratios of 1:0, 1:1, 1:3, 1:7, 1:15 or 0:1. Surviving larvae were preserved in Carnoy`s solution. Each larva`s head was slide-mounted and examined for deformities of the mentum. Polytene chromosome preparations were made from salivary glands of the samemore » animals using acid fuschin staining and examined for reduced relative size of the nuclear organizer (NO) indicative of inhibition of RNA synthesis activity. Incidence of chironomid deformities from control (0:1) sediments ({plus_minus}I SE) was 7.9 {plus_minus} 1.6% (N = 268): 4.0 {plus_minus} 1.5% of 178 control larvae examined displayed NO reduction. Incidence of mentum deformities and of NO reduction increased linearly with each doubling of Detroit R. concentration at 1:0 for deformities; 12.2 {plus_minus} 3.5% (N = 149) for NO reductions. Reduction of NO in a larva was unrelated to mentum condition, indicating that these are independent responses to contaminant stress. Equivalent results were obtained for exposure to single-compound sediments. This is the first documentation of controlled dose-response effects of contaminants on chironomid deformities.« less

Efficiency of selection methods for increased ratio of pupal-larval to adult-larval weight gains in Tribolium.

PubMed

Campo, J L; Cobos, P

1994-01-12

Four lines of Tribolium castaneum were selected in each of three replicates for increased ratio of (pupal-larval) to (adult-larval) weight gains, using selection for increased (pupal-larval) weight gain (PL), selection for decreased (adult-larval) weight gain (AL), direct selection for the ratio (R) and linear selection index of larval, pupal and adult weights (I), respectively, for four generations. Linear index was calculated with economic weights of m(2) -m(3) , m(3) -m(1) and m(1) -m(2) , respectively, with m(1) , m(2) and m(3) being the means for larval, pupal and adult weights. Selection to increase the ratio is considered to be a method to maximize the mean response in (adult-larval) weight while controlling the response in (pupal-adult) weight, and as a form of antagonistic selection to increase the weight gain during a given age period relative to the gain at another age period. Larval, pupal and adult weights were measured at 14, 21 and 28 days after adult emergence, respectively. The selected proportion was 20 % in all lines. The response observed for the ratio differed significantly among lines (p < 0.01), with the I and AL lines having the greatest responses. Line R was less effective in improving the objective of selection, while line PL appeared to be inappropriate. The observed responses for the numerator and denominator weight gains were positive in line PL, and negative in the AL, R and I lines. All lines apart from line PL decreased the (adult-larval) weight, holding (pupal-adult) weight constant. Larval weight showed the greatest influence on the response for the objective of selection. The results for this greater than 1 ratio are compared with results of others for smaller than 1 ratios, in which indirect selection for increased numerator is the more efficient alternative to the selection index. ZUSAMMENFASSUNG: Effizienz Selektionsverfahren zur Verbesserung des Quotienten der Gewichtsentwicklung zwischen Puppe/Larve und Käfer/Larve bei Tribolium. In den jeweils drei Versuchsserien zur Erhöhung des Quotienten (Gewicht von Puppe-Larve/Gewicht von Käfer-Larve) wurden vier Versuchsreihen von Tribolium castaneum untersucht: die Versuchsreihe PL wurde gewählt um die Differenz (Puppengewicht-Larvengewicht) zu erhöhen, die Versuchsreihe AL wurde gewählt um die Differenz (Käfergewicht-Larvengewicht) zu reduzieren, die Versuchsreihe R wurde direkt für den Koeffizienten gewählt und die Auswahl der Versuchsreihe I erfolgte über einen linearen Index, errechnet aus dem Gewicht von Larven, Puppen und Käfern über vier Generationen. Der lineare Index wurde berechnet aus den Gewichten von (m(2) -m(3) ), (m(3) -m(1) ) bzw. (m(1) -m(2) ), wobei m(1) , m(2) und m(3) die Mittelwerte für das Gewicht von Larven, Puppen bzw. Käfern sind. Die Auswahl zur Erhöhung des Quotienten ist eine Methode zur Maximierung des Durchschnittsgewichtsverhältnisses Käfer/Larve, sowie eine antagonische Auswahlform zur Erhöhung der Gewichtszunahme während einer bestimmten Wachstumsperiode im Vergleich zur Gewichtszunahme während einer anderen Wachstumsperiode. Das Selektionsverhältnis belief sich auf 20%. Die beim Quotienten beobachtete Antwort wies bedeutende Unterschiede zwischen Versuchsreihen auf (p < 0.01), wobei die höchsten Antworten bei den Versuchsreihen I und AL beobachtet wurden. Versuchsreihe R war am wenigsten effektiv, während Versuchsreihe PL nicht geeignet schien, das Auswahlziel zu verbessern. Die bei Nenner und Zähler beobachteten Antworten waren positiv bei der Versuchsreihe PL und negativ bei den anderen drei Versuchsreihen. Die Ergebnisse für diesen Quotient größer als 1 wurden mit denen anderer Versuche für Quotienten kleiner als 1 verglichen, bei denen die Auswahl zur Erhöhung des Zählers die effizienteste Alternative zum Auswahlindex ist. RESUMEN: Eficiencia de métodos de selección para incrementar el cociente entre la ganancia en peso de pupa-peso de larva y la ganancia en peso de adulto-peso de larva en Tribolium Cuatro líneas de Tribolium castaneum fueron seleccionadas en cada una de tres repeticiones para incrementar el cociente (peso de pupa-peso de larva)/(peso de adulto-peso de larva); la línea PL fue seleccionada para aumentar la diferencia (peso de pupa-pesp de larva), la línea AL fue seleccionada para disminuir la diferencia (peso de adulto-peso de larva), fa línea R fue seleccionada directamente para el cociente, y la línea I fue seleccionada por medio de un índice lineal basado en los pesos de larva, pupa y adulto, durante cuatro generaciones. El índice lineal se calculó con pesos económicos de (m(2) -m(3) ), (m(3) -m(1) ), y (m(1) -m(2) ) respectivamentee, siendo m(1) , m(2) , y m(3) los valores medios para el peso de larva, pupa y adulto. La selección para aumentar el cociente indicado es un método para maximizar la respuesta en (peso de adulto-peso de larva) controlando al tiempo la respuesta en (peso de pupa-peso de adulto), y es una forma de selección antagónica para aumentar la ganancia de peso durante un periodo de edad en relación con la ganancia en peso durante otro periodo. La proporción de selección due el 20 %. La respuesta observada en el cociente difería significativamente entre lineas (p < 0.01), teniendo las líneas I y AL las mayores respuestas. La línea R fue menos efectiva, mientras que la línea PL parecía inapropiada para mejorar el objetiyo de selección. Las respuestas observadas en el denominador y en el numerador fueron positivas en la línea PL, y negativas en las otras tres líneas. Los resultados para este cociente mayor que 1 se comparan con los de otros experimentos para cocientes menores que 1, en los que la selección para incrementar el numerador es la alternativa más eficiente al índice de selección. 1994 Blackwell Verlag GmbH.

Could the bug Triatoma sherlocki be vectoring Chagas disease in small mining communities in Bahia, Brazil?

PubMed

Almeida, C E; Folly-Ramos, E; Peterson, A T; Lima-Neiva, V; Gumiel, M; Duarte, R; Lima, M M; Locks, M; Beltrão, M; Costa, J

2009-12-01

Searches for Chagas disease vectors were performed at the type locality from which Triatoma sherlocki Papa et al. (Hemiptera: Reduviidae: Triatominae) was described in the municipality of Gentio do Ouro, in the state of Bahia, Brazil, and in a small artisan quarry-mining community approximately 13 km distant in a remote area of the same municipality. The latter site represents a new locality record for this species. Adults, nymphs and exuviae of T. sherlocki were found in 21% of human dwellings, indicating that the species is in the process of domiciliation. Prevalence of Trypanosoma cruzi infection in collected bugs was 10.8%. Simple predictive approaches based on environmental similarity were used to identify additional sites likely suitable for this species. The approach successfully predicted an additional five sites for the species in surrounding landscapes. Ecological and entomological indicators were combined to discuss whether this scenario likely represents an isolated case or an emerging public health problem.

Seven 365-Million-Year-Old Trilobites Moulting within a Nautiloid Conch

NASA Astrophysics Data System (ADS)

Zong, Rui-Wen; Fan, Ruo-Ying; Gong, Yi-Ming

2016-10-01

A nautiloid conch containing many disarticulated exoskeletons of Omegops cornelius (Phacopidae, Trilobita) was found in the Upper Devonian Hongguleleng Formation of the northwestern margin of the Junggar Basin, NW China. The similar number of cephala, thoraces and pygidia, unbroken thoraces, explicit exuviae, and lack of other macrofossils in the conch, indicate that at least seven individual trilobites had moulted within the nautiloid living chamber, using the vacant chamber of a dead nautiloid as a communal place for ecdysis. This exuvial strategy manifests cryptic behaviour of trilobites, which may have resulted from the adaptive evolution induced by powerful predation pressure, unstable marine environments, and competition pressure of organisms occupying the same ecological niche in the Devonian period. The unusual presence of several trilobites moulting within a nautiloid conch is possibly associated with social behaviours in face of a serious crisis. New materials in this study open a window for understanding the survival strategy of marine benthic organisms, especially predator-prey interactions and the behavioural ecology of trilobites in the middle Palaeozoic.

Tardigrades from Nahuel Huapi National Park (Argentina, South America) with descriptions of two new Macrobiotidae species.

PubMed

Roszkowska, Milena; Stec, Daniel; Ciobanu, Daniel Adrian; Kaczmarek, Łukasz

2016-04-21

In 31 samples of mosses and lichens collected in the Argentinean province of Río Negro, 657 tardigrades, 53 exuviae and 219 free-laid eggs were found. In total, 20 species were identified: Diphascon chilenense, Dip. mitrense, Echiniscus bigranulatus, Ech. corrugicaudatus, Ech. merokensis merokensis, Ech. testudo, Hebesuncus mollispinus, Hypsibius convergens, Macrobiotus cf. anderssoni, Mac. andinus, Mac. kazmierskii, Mac. patagonicus, Mesobiotus szeptyckii, Mes. pseudoblocki sp. nov., Milnesium argentinum, Mil. beatae, Mil. brachyungue, Mil. granulatum, Mopsechiniscus granulosus, Minibiotus pseudostellarus sp. nov. Of the two new species, Mesobiotus pseudoblocki sp. nov. is most similar to Mes. blocki, but it differs mainly by the lack of dentate lunules, smaller eggs and presence of reticular design on egg processes. Minibiotus pseudostellarus sp. nov. is most similar to Min. constellatus, Min. eichhorni, Min. sidereus or Min. vinciguerrae, but it differs from them by the presence of 'pseudo-star'-shaped pores in the dorsal cuticle instead of fully developed 'stars' and by other morphometric characters.

Stenochironomus munteanpurin sp. n., a new leaf-mining species from Brazil (Diptera: Chironomidae).

PubMed

Amora, Gizelle; Hamada, Neusa; Pinho, Luiz C

2018-02-21

Stenochironomus munteanpurin sp. n. is described and illustrated in all life stages, except eggs, from Brazil. The male is very similar to Stenochironomus quadrinotatus Borkent, 1984 due to same overall pattern of pigmentation. The new species can be distinguished from the other related species principally in immature stages: larva with labral lamella arranged in two groups with one or two conical-shaped teeth, spicules of pecten epipharyngis arranged in a row, unequal and irregularly distributed sizes, SI bifurcated, SII pinnate, SIII pinnate setae and, larval exuviae is compacted; pupa with shagreens being in all TI, less number of hooklets in TII, TVII without shagreens and presence of shagreen in conjunctive III/IV and IV/V. Adult male is very similar to the one of S. quadrinotatus but can be distinguished by combination of the TIX with more than 25 setae medially and phallapodeme curved anteriorly. The new species were collected in the following Brazilian states: Rio de Janeiro, Santa Catarina, Bahia and Acre.

Gynacantha dryadula sp. nov. from the Guiana Shield (Odonata, Anisoptera: Aeshnidae).

PubMed

Neiss, Ulisses Gaspar; Marmels, Jürg DE

2017-04-20

The new species is described and illustrated on the basis of two reared, subteneral males from Brazil, their larval exuviae, a mature male from French Guiana, a mature female from Venezuela, and a mature female from Surinam. One of the Brazilian males is the holotype (BRAZIL, Amazonas State, Manaus, Reserva Florestal Ducke, BR 174-km 26, trail to Acará creek, 02º55'47"S, 59º58'22"W, 0.7 m elevation, deposited in INPA). The new species (total length 50-54 mm) differs from other small species of same genus by color pattern of thorax, middle and hind tibiae dark with external (dorsal) yellow streak, male cercus with truncated tip lacking apical spine, and male epiproct reaching or slightly surpassing midlength of cercus. The larva, besides of its small size (28-31 mm), has an epiproct with well-developed and slightly diverging apical spines and an unusually long paraproct.

The potential for trichogramma releases to suppress tip moth populations in pine plantations

Treesearch

David B. Orr; Charles P.-C Suh; Michael Philip; Kenneth W. McCravy; Gary L. DeBarr

1999-01-01

Because the Nantucket pine tip moth is a native pest, augmentation (mass-release) of native natural enemies may be the most promising method of tip moth biocontrol. The tip moth has several important egg, larval, and pupal parasitoids. Egg parasitoids are most effective as biocontrol agents because they eliminate the host before it reaches a damaging stage....

Three New Species of the Genus Tripteroides, Subgenus Tripteroides Giles (Diptera: Culicidae)

DTIC Science & Technology

1968-12-01

termi- nalia and legs mounted; #NY 123-11 from Khaoyai. Five specimens came from Chiang Mai : #T-2195-10L and #T-2123-1P from Doi Sutep; #T-2413-lP...examined. The Thailand material contained 1 whole larva and 17 males with 9 associated larval and pupal skins from Chiang Mai ; 3 males, 2 with

Heat stress but not inbreeding affects offensive sperm competitiveness in Callosobruchus maculatus

PubMed Central

Lieshout, Emile; Tomkins, Joseph L; Simmons, Leigh W

2013-01-01

Environmental and genetic stress have well-known detrimental effects on ejaculate quality, but their concomitant effect on male fitness remains poorly understood. We used competitive fertilization assays to expose the effects of stress on offensive sperm competitive ability in the beetle Callosobruchus maculatus, a species where ejaculates make up more than 5% of male body mass. To examine the effects of environmental and genetic stress, males derived from outcrosses or sib matings were heat shocked at 50°C for 50 min during the pupal stage, while their siblings were maintained at a standard rearing temperature of 28°C. Heat-shocked males achieved only half the offensive paternity success of their siblings. While this population exhibited inbreeding depression in body size, sperm competitiveness was unaffected by inbreeding, nor did the effect of heat shock stress on sperm competitiveness depend on inbreeding status. In contrast, pupal emergence success was increased by 34% among heat-stressed individuals, regardless of their inbreeding status. Heat-shocked males' ejaculate size was 19% reduced, but they exhibited 25% increased mating duration in single mating trials. Our results highlight both the importance of stress in postcopulatory sexual selection, and the variability among stressors in affecting male fitness. PMID:24101978

FGF signaling supports Drosophila fertility by regulating development of ovarian muscle tissues

PubMed Central

Irizarry, Jihyun; Stathopoulos, Angelike

2015-01-01

The thisbe (ths) gene encodes a Drosophila fibroblast growth factor (FGF), and mutant females are viable but sterile suggesting a link between FGF signaling and fertility. Ovaries exhibit abnormal morphology including lack of epithelial sheaths, muscle tissues that surround ovarioles. Here we investigated how FGF influences Drosophila ovary morphogenesis and identified several roles. Heartless (Htl) FGF receptor was found expressed within somatic cells at the larval and pupal stages, and phenotypes were uncovered using RNAi. Differentiation of terminal filament cells was affected, but this effect did not alter ovariole number. In addition, proliferation of epithelial sheath progenitors, the apical cells, was decreased in both htl and ths mutants, while ectopic expression of the Ths ligand led to these cells’ over-proliferation suggesting that FGF signaling supports ovarian muscle sheath formation by controlling apical cell number in the developing gonad. Additionally, live imaging of adult ovaries was used to show that htl RNAi mutants, hypomorphic mutants in which epithelial sheaths are present, exhibit abnormal muscle contractions. Collectively, our results demonstrate that proper formation of ovarian muscle tissues is regulated by FGF signaling in the larval and pupal stages through control of apical cell proliferation and is required to support fertility. PMID:25958090

Dual-treatment autodissemination station with enhanced transfer of an insect growth regulator to mosquito oviposition sites.

PubMed

Wang, Yi; Suman, Devi S; Bertrand, Jacques; Dong, Limin; Gaugler, Randy

2014-08-01

The Asian tiger mosquito, Aedes albopictus (Skuse), transmits important arboviral diseases and displaces native species. This peridomestic mosquito deposits eggs in natural and artificial containers. Container larval habitats tend to be cryptic and, therefore, difficult to reach by conventional insecticide treatments. We have developed an autodissemination station that transfers the insect growth regulator, pyriproxyfen, from the station to oviposition sites. Mosquitoes visiting the station become contaminated with an oil sticker followed by pyriproxyfen powder before exiting. In a room (31 m(3) ) bioassay a single station consistently achieved 100% Ae. albopictus pupal mortality against 10 oviposition containers. In a greenhouse (200 m(3) ) assay with two stations and 12 oviposition cups, 91.7% of the cups had been contaminated as shown, and 57.1% pupal mortality was recorded. Pyriproxyfen transfer was also detected by visualizing mosquito 'tarsal prints' using a fluorescent dye. The oil and pyriproxyfen powder dual-treatment station enhanced autodissemination efficacy by increasing toxicant attachment and retention on contaminated females. The autodissemination station offers a targeted, less environmentally damaging approach to manage cryptic container species. © 2013 Society of Chemical Industry.

Yorkie Facilitates Organ Growth and Metamorphosis in Bombyx.

PubMed

Liu, Shumin; Zhang, Panli; Song, Hong-Sheng; Qi, Hai-Sheng; Wei, Zhao-Jun; Zhang, Guozheng; Zhan, Shuai; Liu, Zhihong; Li, Sheng

2016-01-01

The Hippo pathway, which was identified from genetic screens in the fruit fly, Drosophila melanogaster, has a major size-control function in animals. All key components of the Hippo pathway, including the transcriptional coactivator Yorkie that is the most critical substrate and downstream effector of the Hippo kinase cassette, are found in the silkworm, Bombyx mori. As revealed by microarray and quantitative real-time PCR, expression of Hippo pathway genes is particularly enriched in several mitotic tissues, including the ovary, testis, and wing disc. Developmental profiles of Hippo pathway genes are generally similar (with the exception of Yorkie) within each organ, but vary greatly in different tissues showing nearly opposing expression patterns in the wing disc and the posterior silk gland (PSG) on day 2 of the prepupal stage. Importantly, the reduction of Yorkie expression by RNAi downregulated Yorkie target genes in the ovary, decreased egg number, and delayed larval-pupal-adult metamorphosis. In contrast, baculovirus-mediated Yorkie(CA) overexpression upregulated Yorkie target genes in the PSG, increased PSG size, and accelerated larval-pupal metamorphosis. Together the results show that Yorkie potentially facilitates organ growth and metamorphosis, and suggest that the evolutionarily conserved Hippo pathway is critical for size control, particularly for PSG growth, in the silkworm.

Heat stress but not inbreeding affects offensive sperm competitiveness in Callosobruchus maculatus.

PubMed

Lieshout, Emile; Tomkins, Joseph L; Simmons, Leigh W

2013-09-01

Environmental and genetic stress have well-known detrimental effects on ejaculate quality, but their concomitant effect on male fitness remains poorly understood. We used competitive fertilization assays to expose the effects of stress on offensive sperm competitive ability in the beetle Callosobruchus maculatus, a species where ejaculates make up more than 5% of male body mass. To examine the effects of environmental and genetic stress, males derived from outcrosses or sib matings were heat shocked at 50°C for 50 min during the pupal stage, while their siblings were maintained at a standard rearing temperature of 28°C. Heat-shocked males achieved only half the offensive paternity success of their siblings. While this population exhibited inbreeding depression in body size, sperm competitiveness was unaffected by inbreeding, nor did the effect of heat shock stress on sperm competitiveness depend on inbreeding status. In contrast, pupal emergence success was increased by 34% among heat-stressed individuals, regardless of their inbreeding status. Heat-shocked males' ejaculate size was 19% reduced, but they exhibited 25% increased mating duration in single mating trials. Our results highlight both the importance of stress in postcopulatory sexual selection, and the variability among stressors in affecting male fitness.

Efficiency of vibrational sounding in parasitoid host location depends on substrate density.

PubMed

Fischer, S; Samietz, J; Dorn, S

2003-10-01

Parasitoids of concealed hosts have to drill through a substrate with their ovipositor for successful parasitization. Hymenopteran species in this drill-and-sting guild locate immobile pupal hosts by vibrational sounding, i.e., echolocation on solid substrate. Although this host location strategy is assumed to be common among the Orussidae and Ichneumonidae there is no information yet whether it is adapted to characteristics of the host microhabitat. This study examined the effect of substrate density on responsiveness and host location efficiency in two pupal parasitoids, Pimpla turionellae and Xanthopimpla stemmator (Hymenoptera: Ichneumonidae), with different host-niche specialization and corresponding ovipositor morphology. Location and frequency of ovipositor insertions were scored on cylindrical plant stem models of various densities. Substrate density had a significant negative effect on responsiveness, number of ovipositor insertions, and host location precision in both species. The more niche-specific species X. stemmator showed a higher host location precision and insertion activity. We could show that vibrational sounding is obviously adapted to the host microhabitat of the parasitoid species using this host location strategy. We suggest the attenuation of pulses during vibrational sounding as the energetically costly limiting factor for this adaptation.

Pupal melanization is associated with higher fitness in Spodoptera exigua

PubMed Central

Liu, Sisi; Wang, Mo; Li, Xianchun

2015-01-01

Melanism has long been thought to be a habitat adaptation with a fitness cost. Here we reported a homozygous melanic strain (SEM) of Spodoptera exigua (Hübner) (Insecta: Lepidoptera: Noctuidae) established with black pupae spontaneously occurring within a typical laboratory population (SEW). The melanization is expressed globally, and only in the pupal stage. After pupation, the melanic SEM pupae gradually accumulate melanin to become completely black within 6 hours, whereas the wild-type SEW pupae gradually turn yellow-brown. The melanic SEM strain exhibits faster development in all life stages, heavier pupa weight, more mating time, higher fecundity, and accordingly, higher net reproductive rate and population trend index. While no reproductive isolation was observed between the SEM and SEW strains, the mating times per female of the reciprocal crosses and the SEM intracrosses were significantly higher than those of the SEW intracrosses. This represents a rare case of melanization that has fitness gains, rather than costs. Analysis of the life-history traits of this case and 14 previously reported cases of insect melanism indicate that none of melanization origin, stage, space and variation type determining whether melanism will cause fitness gain or cost. PMID:26039886

Antibiosis in Soybean Genotypes and the Resistance Levels to Spodoptera eridania (Cramer) (Lepidoptera: Noctuidae).

PubMed

Souza, B H S; Silva, A G; Janini, J C; Boica Júnior, A L

2014-12-01

The southern armyworm (SAW) Spodoptera eridania (Cramer) is one of the most common armyworm species defoliating soybeans. Preliminary screening trials have indicated that some soybean genotypes exhibit resistance to SAW. Therefore, in this study, we evaluated the development of SAW larvae fed on ten soybean genotypes in order to identify genotypes with antibiosis-type resistance. Neonate SAW larvae were daily fed with young leaves collected from plants at the vegetative growth stages V4-V5. Larval development and survival were recorded. Genotypes PI 227687 and PI 227682 delayed larval, pupal, and larva-adult development and yielded larvae with the lowest weight and survival and pupae with the lowest weight. Genotypes IAC 100 and DM 339 also negatively affected larval and pupal development and larval survival but at a lower level. Based on our results, the soybean lines PI 227687 and PI 227682 could be used as sources of genes for soybean breeding programs aiming to develop high yield, SAW-resistant cultivars. Moreover, further trials must be carried out under field conditions to validate if the commercial cultivars IAC 100 and DM 339, which expressed moderate levels of antibiosis-type resistance in the laboratory, are effective in suppressing SAW larvae populations.

Acute, sublethal, and combination effects of azadirachtin and Bacillus thuringiensis on the cotton bollworm, Helicoverpa armigera

PubMed Central

Abedi, Zahra; Saber, Moosa; Vojoudi, Samad; Mahdavi, Vahid; Parsaeyan, Ehsan

2014-01-01

Abstract The cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a polyphagous and cosmopolitan insect pest that causes damage to various plants. In this study, the lethal and sublethal effects of azadirachtin and Bacillus thuringiensis Berliner sub sp . kurstaki (Bacillales: Bacillaceae) were evaluated on third instar H. armigera under laboratory conditions. The LC50 values of azadirachtin and Bt were 12.95 and 96.8 µg a.i./mL, respectively. A total mortality of 56.7% was caused on third instar larvae when LC20 values of the insecticides were applied in combination with each other. The LT50 values of azadirachtin and Bt were 4.8 and 3.6 days, respectively. The results of the sublethal study showed that the application of LC30 value of azadirachtin and Bt reduced the larval and pupal weight and increased larval and pupal duration of H. armigera . The longevity and fecundity of female adults were affected significantly by the insecticides. Female fecundity was reduced by the treatments, respectively. The lowest adult emergence ratio and pupation ratio were observed in the azadirachtin treatment. The results indicated that both insecticides have high potential for controlling of the pest. PMID:25373177

Hormonal control of GTP cyclohydrolase I gene expression and enzyme activity during color pattern development in wings of Precis coenia.

PubMed

Sawada, H; Nakagoshi, M; Reinhardt, R K; Ziegler, I; Koch, P B

2002-06-01

Color patterns of butterfly wings are composed of single color points represented by each scale. In the case of Precis coenia, at the end of pupal development, different types of pigments are synthesized sequentially in the differently colored scales beginning with white (pterins) followed by red (ommatins) and then black (melanin). In order to explain how formation of these different colors is regulated, we examined the expression of an mRNA-encoding guanosine triphosphate-cyclohydrolase I (GTP-CH I; EC 3.5.4.16), the first key enzyme in the biosynthesis of pteridines, during pigment formation in the wings of P. coenia. The strongest positive signal was recognized around pigment formation one day before butterfly emergence. This GTP-CH I gene expression is paralleled by GTP-CH I enzyme activity measured in wing extracts. We also investigated the effect of 20-hydroxyecdysone on the expression of GTP-CH I mRNA and the enzyme activity during color formation. The results strongly suggest that the onset and duration of the expression of a GTP-CH I mRNA is triggered by a declining ecdysteroid hormone titer during late pupal development.

Substrate effects on pupation and adult emergence of Hermetia illucens (Diptera: Stratiomyidae).

PubMed

Holmes, L A; Vanlaerhoven, S L; Tomberlin, J K

2013-04-01

Black soldier flies, Hermetia illucens (L.) (Diptera: Stratiomyidae), are of particular interest for their applications in waste management. Feeding on decaying organic waste, black soldier flies successfully reduce manure in confined animal feeding operations of poultry, swine, and cattle. To optimize waste conversion in confined animal feeding operations and landfill facilities, it is imperative to optimize black soldier fly development. Unfortunately, black soldier flies only convert waste during their larval feeding stages and therefore it is of interest to optimize the nonfeeding stages of development, specifically, the postfeeding and pupal stages. The time spent in these stages is thought to be determined by the pupation substrate encountered by the postfeeding larvae. The objective of this study was to determine the effect different pupation substrates have on postfeeding development time, pupation time, and adult emergence success. Five pupation substrates were compared: wood shavings, potting soil, topsoil, sand, and nothing. Postfeeding larvae took longer to reach pupation in the absence of a pupation substrate, although reaching pupation in the shortest time in potting soil and wood shavings. The time spent in the pupal stage was shortest in the absence of a pupation substrate. However, fewer adults emerged when a pupation substrate was not provided.

Polypedilum nubifer, a Chironomid Midge (Diptera: Chironomidae) new to Florida that has nuisance potential

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

Jacobsen, R.E.; Perry, S.A.

2007-03-15

We document the first record of Polypedilum nubifer in Pan-America. This eurytopic species often reaches severe nuisance population sizes in Australia, Asia, and Hawaii in warm, shallow, eutrophic waters subject to drying. A large population was discovered in newly-constructed infiltration basins and neighboring marshes along the eastern boundary of Everglades National Park. Presently, this population appears minimally invasive to Park marshes and is far removed from urban areas. However, we anticipate this species could disperse and attain nuisance population sizes in suitable urban and agricultural habitats in south Florida. (author)

Temporal and spatial assessment of water quality, physical habitat, and benthic communities in an impaired agricultural stream in California's San Joaquin Valley.

PubMed

Hall, Lenwood W; Killen, William D

2005-01-01

The goal of this study was to characterize and discuss the relationships among water quality, physical habitat, and benthic community data collected annually over a three-year period (2000--2002) in an impaired agricultural stream (Orestimba Creek) in California's San Joaquin River watershed. Conductivity, pH, and turbidity were the most important water quality conditions influencing the various benthic metrics. Significantly higher flow conditions and lower dissolved oxygen values were reported in Orestimba Creek in 2001; increased turbidity conditions were reported in 2002. Channel alteration, riparian buffer, sediment deposition, and channel flow were the most important physical habitat metrics influencing the various benthic metrics. Higher total physical habitat scores were reported in 2001 when compared with 2002. The most dominant benthic taxa collected during all three years of sampling were oligochaetes and chironomids. Oligochaetes are found in stressful environments while chironomids can be either sensitive or tolerant to environmental stressors depending on the species. Populations of both daphnids and the exotic clam Corbicula were reported to increase over time. Both of these taxa are generally tolerant to most types of environmental degradation. The exception is that daphnids are highly sensitive to organophosphate insecticides. The % filterers increased over time, which suggests an increase in environmental disturbance. The % collectors decreased from 2000 to 2002, which suggests an improvement in environmental conditions. The presence of approximately 100 taxa in Orestimba Creek during each of the three years of sampling implies that benthic communities in this stream are fairly diverse, considering their ephemeral environment, but without a clear definition of benthic community expectations based on established referenc conditions it is unknown if this water body is actually impaired.

High diet overlap between native small-bodied fishes and nonnative fathead minnow in the Colorado River, Grand Canyon, Arizona

USGS Publications Warehouse

Seegert, Sarah E. Zahn; Rosi-Marshall, Emma J.; Baxter, Colden V.; Kennedy, Theodore A.; Hall, Robert O.; Cross, Wyatt F.

2014-01-01

River regulation may mediate the interactions among native and nonnative species, potentially favoring nonnative species and contributing to the decline of native populations. We examined food resource use and diet overlap among small-bodied fishes in the Grand Canyon section of the Colorado River as a first step in evaluating potential resource competition. We compared the diets of the predominant small-bodied fishes (native Speckled Dace Rhinichthys osculus, juvenile Flannelmouth Sucker Catostomus latipinnis, and juvenile Bluehead Sucker C. discobolus, and nonnative Fathead Minnow Pimephales promelas) across seasons at four sites downstream of Glen Canyon Dam using nonmetric multidimensional scaling and Schoener's similarity index. The diets of these fishes included diatoms, amorphous detritus, aquatic invertebrates (especially simuliid and chironomid larvae), terrestrial invertebrates, and terrestrial vegetation. Diets varied with season and were affected by high turbidity. Fish consumed more amorphous detritus and terrestrial vegetation during the summer monsoon season (July–September), when turbidity was higher. The diets of all species overlapped, but there was large variation in the degree of overlap. The diets of juvenile suckers and Fathead Minnows were most similar, while Speckled Dace had relatively distinct diets. The differences took the form of higher proportions of diatoms and amorphous detritus in the diets of Bluehead Suckers and Fathead Minnows and higher proportions of simuliids and chironomids in those of Speckled Dace. If food resources are or become limiting, diet overlap suggests that competition may occur among native and nonnative species, which could have implications for the population dynamics of these fishes and for the management of the Colorado River ecosystem in Grand Canyon.

Changes in the deep-water benthos of eastern Lake Erie between 1979 and 1993

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

Dermott, R.; Kerec, D.

1995-06-01

In order to examine changes of the benthic community and benthic biomass as a result of mussel colonization, a survey of the deep-water benthic fauna in eastern Lake Erie was repeated in 1993 using the same sites and methods as in a 1979 survey. During 1979, the community beyond 30 m was dominated by oligochaete worms and the burrowing amphipod Diporeia, which represented 50 and 40% of the total benthic biomass respectively. By 1993, quagga mussels (Dreissena bugensis) formed over 90% of the benthic biomass. Mussels were present at all 13 sites. Densities of individuals >2 mm in length averagedmore » 3,241 mussels m{sup -2}. Of these mussels, 97% were quagga mussels. Total density of all sizes retained on a 180 {mu}m sieve averaged 34,800 mussels m{sup -2} but total biomass decreased from 1.58 to 0.98 g m{sup -2}. The density of the amphipod Diporeia was reduced from 1,844 in 1979 to 218 m{sup -2} in 1993. While present at all sites during 1979, Diporeia remained common only at two sites and were absent at 8 of the 13 sites in 1993. The native fingernail clams, Pisidium spp., were reduced from 327 to 82 m{sup -2}. No significant reduction occurred in the worm and chironomid populations, however the dry biomass of the chironomids was reduced from 0.07 to 0.0008 g m{sup -2}. These reductions may be due to competition with the mussels for freshly settling algae. The meiofauna, which included small nematodes, ostracods, and harpacticoids retained on a 180 {mu}m sieve, all increased in density. Perhaps they benefited from an increase in the detritus deposited as pseudofeces around the mussels.« less

Assessing dimethoate contamination in temperate and tropical climates: potential use of biomarkers in bioassays with two chironomid species.

PubMed

Domingues, Inês; Guilhermino, Lúcia; Soares, Amadeu M V M; Nogueira, António J A

2007-08-01

This study was conducted to investigate the potential use of biomarkers in bioassays with chironomids to assess contamination by pesticides in temperate and tropical climates. Two species of midge were studied, the widespread Chironomus riparius and the tropical Kiefferulus calligaster (Kieffer, 1911). Preliminary studies included investigations of the effects of temperature on larval development and the influence of larval age on normal variability of cholinesterase (ChE) and glutathione S-transferase (GST) activities and protein content. In the second phase, the influence of two abiotic factors particularly important in tropical conditions (temperature and oxygen concentration) and of the organophosphorous (OP) insecticide dimethoate on biochemical and conventional endpoints was investigated. Results showed that K. calligaster is morphologically and physiologically similar to C. riparius and for both, the time of larval development decreases with the increase of temperature. Moreover, 3rd and 4th instars appeared to be the most suitable for biomarkers determinations. ChE activity seems to be valuable biomarker regarding temperature and dissolved oxygen (DO) variations, while some caution should be taken when using GST as an environmental biomarker, since it shows some dependence of these parameters. C. riparius was more sensitive to dimethoate than K. calligaster suggesting that the use of bioassays with the former species in tropical conditions may overestimate the toxicity of OP pesticides to autochthonous species. When testing sub-lethal effects of dimethoate to C. riparius, ChE activity showed to be a very sensitive parameter detecting significant effects at the lowest concentration that caused emergence delay of larvae, suggesting that it is an ecologically relevant parameter.

Chironomus group classification according to the mapping of polytene chromosomes

NASA Astrophysics Data System (ADS)

Salleh, Syafinaz; Kutty, Ahmad Abas

2013-11-01

Chironomus is one of the important genera in Chironomidae family since they are widely diverse and abundance in aquatic ecosystem. Since Chironomus is very diverse, taxonomic work on this genus is very difficult and incomplete. Objective of this study is to form group classification of Chironomus according to the polytene chromosome mapping. The specific characteristics of polytene chromosomes in the salivary gland appeared to be particularly promising for taxonomic diagnosis of chironomid species. Chironomid larvae were collected from pristine sites at Sg. Langat and cultured in laboratory to reach fourth instar stage. The salivary glands were removed from larvae and chromosomes were stained with aceto orcein. Results showed that polytene chromosomes of Chironomus comprise of three long metacentric or submetacentric arms (BF, CD and AE arms) and one short acrocentric (G arm). In regards to nucleolar organizing region (NOR), Balbiani ring (BR), puffings and chromosome rearrangement, a number of four groups of different banding patterns were found. Two groups called as G group A and B have common NOR on arm BF and BR on arm G. However, group A has rearrangement pattern on arm CD and not in group B. This makes group B separated from group A. Another two groups called as groups C and D do not have common NOR on arm BF and also BR on arm G. Groups C and D were separated using arms G and arm AE. At arm G, only group C rearrangement pattern at unit 23c whereas group D was found to have large NOR at arm G and as well as arm AE, only group D has rearrangement pattern at unit 12c. This study indicates that chromosome arrangement could aid in revealing Chironomus diversity.

Biological and genetic characteristics of Glyptotendipes tokunagai (Diptera: Chironomidae) on the basis of successive rearing of forty-two generations over seven years under laboratory conditions.

PubMed

Baek, Min Jeong; Yoon, Tae Joong; Kang, Hyo Jeong; Bae, Yeon Jae

2014-10-01

Members of the nonbiting midge family Chironomidae have been used worldwide as water-quality indicators or toxicity test organisms. The purpose of this study was to establish the chironomid Glyptotendipes tokunagai Sasa as a new test species by conducting successive rearing under laboratory conditions. We monitored biological and genetic aspects of >42 successive generations over 7 yr, and also compared the development of the 39th generation with the fourth generation under five constant temperatures of 15, 20, 25, 30, and 35°C. We observed that the number of eggs in an egg mass and the adult body sizes decreased rapidly in the early generations, and thereafter tended to stabilize from the fifth generation to the 42nd generation. In all generations, the mean hatching rate was >75%. Males were predominant in the early generations, but the sex ratio increased to 0.5 (ranged 0.24-0.61) in later generations. The genetic divergence of the reared generations, analyzed by using the mitochondrial cytochrome c oxidase subunit I gene, decreased from 0.0049 to 0.0004 as the generations progressed. In comparison with the fourth generation, the mortality and developmental time of the 39th generation were generally greater, and the adult body sizes were generally smaller. The estimated low developmental threshold temperatures of eggs, male larvae to male adults, and female larvae to female adults were 9.6, 11.3, and 9.7°C, respectively. The optimal rearing temperature was determined to be 25°C. This is the first record of domesticated rearing of a wild chironomid species under laboratory conditions for >7 yr.

Diet and habitat use by age-0 deepwater sculpins in northern Lake Huron, Michigan and the Detroit River

USGS Publications Warehouse

Roseman, Edward F.

2014-01-01

Deepwater sculpins (Myoxocephalus thompsonii) are an important link in deepwater benthic foodwebs of the Great Lakes. Little information exists about deepwater sculpin spawning habits and early life history ecology due to difficulty in sampling deep offshore habitats. Larval and age-0 deepwater sculpins collected in northern Lake Huron and the Detroit River during 2007 were used to improve our understanding of their habitat use, diet, age, and growth. Peak larval density reached 8.4/1000 m3 in the Detroit River during April and was higher than that in Lake Huron. Offshore bottom trawls at DeTour and Hammond Bay first collected benthic age-0 deepwater sculpins in early September when fish were ≥ 25 mm TL. Otolith analysis revealed that hatch dates for pelagic larvae occurred during late March and larvae remained pelagic for 40 to 60 days. Diet of pelagic larvae (10–21 mm TL) was dominated by calanoid copepods at all sample locations. Diets of benthic age-0 fish varied by location and depth: Mysis and chironomids were prevalent in fish from Hammond Bay and the 91 m site at DeTour, but only chironomids were found in fish from the 37 m DeTour site. This work showed that nearshore epilimnetic sites were important for pelagic larvae and an ontogenetic shift from pelagic planktivore to benthivore occurred at about 25 mm TL in late summer. Age analysis showed that larvae remained pelagic long enough to be transported through the St. Clair–Detroit River system, Lake Erie, and the Niagara River, potentially contributing to populations in Lake Ontario.

Diversity of Non-Biting Midge Larvae Assemblages in the Jacuí River Basin, Brazil

PubMed Central

Floss, Elzira Cecília Serafini; Kotzian, Carla Bender; Spies, Márcia Regina; Secretti, Elisangela

2012-01-01

The richness and composition of a mountain-river chironomid larvae assemblage in the Jacuí River basin, Brazil were studied, and compared with other riverine non-biting midge larvae assemblages previously studied in the country. Additionally, the influence of some regional-scale environmental characteristics on the spatial distribution of these assemblages was tested. The specimens were collected at 12 sites in the middle course of the Jacuí River basin (in the state of Rio Grande do Sul) between April 2000 and May 2002. Around 100 taxa were recorded. The dominant taxa belonged to the genera Rheotanytarsus, Cricotopus, Polypedilum, and Pseudochironomus. Twenty-two rare taxa were found, representing 22% of the total of taxa inventoried. Fourteen genera (Aedokritus, Axarus, Endotribelos, Kiefferulus, Manoa, Oukuriella, Phaenopsectra, Stenochironomus, Xenochironomus, Xestochironomus, Cardiocladius, Metriocnemus, Paracladius, and Rheocricotopus) represent new occurrences in Rio Grande do Sul. The similarity analysis of the chironomid larvae assemblages inventoried in 32 regions of Brazil indicated five groups with similarity higher than 50%. The groups, when the effects of spatial autocorrelation were removed, displayed a weak positive correlation between the assemblage composition and the aquatic system or hydraulic conditions and the hydrographic basin, and a weak negative correlation in relation to the biome. The altitude showed no correlation with the composition of the assemblage. The relatively high richness of the region surveyed in relation to other Brazilian regions corroborates some tendencies already noted in other parts of the world, such as: i) lotic systems may constitute an exception to the rule that diversity is greater in tropical regions, ii) regions of transitional relief may contain the greatest richness of Chironomidae, and iii) in rivers, the group might have its spatial distribution influenced to a greater extent by local environmental characteristics than by regional ones. PMID:23451870

Food resource partitioning by nine sympatric darter species

USGS Publications Warehouse

van Snik, Gray E.; Boltz, J.M.; Kellogg, K.A.; Stauffer, J.R.

1997-01-01

We compared the diets among members of the diverse darter community of French Creek, Pennsylvania, in relation to seasonal prey availability, feeding ontogeny, and sex. Prey taxa and size attributes were characterized for nine syntopic darter species; taxon, size, and availability of macroinvertebrate prey were also analyzed from Surber samples. In general, darters fed opportunistically on immature insects; few taxa were consumed in greater proportions than they were found in the environment. Some variation in diet composition was expressed, however, among different life stages and species. Juvenile darters consumed smaller prey and more chironomids than did adults. Etheostoma blennioides and E. zonale consumed the fewest taxa (2-3), whereas E. maculatum, E. variatum, and Percina evides bad the most diverse diets (7-10 taxa). Etheostoma maculatum, E. flabellare, E. variatum, and P. evides consumed larger prey (1-13 mm in standard length), whereas E. blennioides, E. caeruleum, E. camurum, E. tippecanoe, and E. zonale rarely consumed prey longer than 6 mm. Percina evides fed on larger prey, fewer chironomids, and more fish eggs than Etheostoma species. Females consumed more prey than males and overlapped less in diet composition with males during the spawning season than afterwards. Fish diets did not seem related to habitat use. Greater trophic partitioning was observed in April, when prey resources were scarce, than in July, when prey were abundant. Darter species fed opportunistically when prey were dense, whereas they partitioned food resources mainly through the prey size dimension when prey were less abundant. The divergence of darter diets during a period of low food availability may be attributed to interspecific competition. Alternatively, the greater abundance of large prey in April may have facilitated better prey size selectivity, resulting in less overlap among darter species.

20th century human pressures drive reductions in deepwater oxygen leading to losses of benthic methane-based food webs

NASA Astrophysics Data System (ADS)

Belle, Simon; Millet, Laurent; Verneaux, Valérie; Lami, Andrea; David, Etienne; Murgia, Laurie; Parent, Claire; Musazzi, Simona; Gauthier, Emilie; Bichet, Vincent; Magny, Michel

2016-04-01

Freshwater lakes play a key role in the global carbon cycle as sinks (organic carbon sequestration) and sources (greenhouse gas emissions). Understanding the carbon cycle response to environmental changes is becoming a crucial challenge in the context of global warming and the preponderance of human pressures. We reconstructed the long-term (1500 years) evolution of trophic functioning of the benthic food web, based on methanotrophic ancient DNA and chironomid isotope analyses). In addition, human land use is also reconstructed in three different lakes (eastern France, Jura Mountains). Our findings confirm that the benthic food web can be highly dependent on methane-derived carbon (up to 50% of the chironomid biomass) and reveal that the activation of this process can correspond to a natural functioning or be a consequence of anthropic perturbation. The studied lakes also showed a similar temporal evolution over the last century with the disappearance of the profundal aquatic insects (Chironomidae, Diptera), considered as keystone for the whole lake food web (e.g., coupling benthic-pelagic), inducing a potential collapse in the transfer of methane to top consumers. This functional state, also called the dead zone expansion, was caused by the change in human land-use occurring at the beginning of the 20th century. The strong modification of agro-pastoral practices (e.g., fertilization practices, intensive grazing, and sewage effluent) modified the influx of nutrients (by diffuse and/or point-source inputs) and induced a significant increase in the trophic status and organic matter sedimentation to reach unprecedented values. Further studies should be planned to assess dead zone expansion and, according to the regime shift theory, to provide environmental tipping points for sustainable resource management.

No association between the use of Bti for mosquito control and the dynamics of non-target aquatic invertebrates in French coastal and continental wetlands.

PubMed

Lagadic, Laurent; Schäfer, Ralf B; Roucaute, Marc; Szöcs, Eduard; Chouin, Sébastien; de Maupeou, Jérôme; Duchet, Claire; Franquet, Evelyne; Le Hunsec, Benoit; Bertrand, Céline; Fayolle, Stéphanie; Francés, Benoît; Rozier, Yves; Foussadier, Rémi; Santoni, Jean-Baptiste; Lagneau, Christophe

2016-05-15

The environmental safety of Bacillus thuringiensis subsp. israelensis (Bti) is still controversial, mainly because most of the previous field studies on its undesired effects were spatially limited and did not address the relationship between community similarity and application time and frequency. No general statement can therefore be drawn on the usage conditions of Bti that insure protection of non-target organisms. The present study was conducted in eight sites distributed over the main geographical sectors where mosquito control is implemented in mainland France and Corsica. Changes in non-target aquatic invertebrates were followed at elapsed time after repeated applications of two Bti formulations (VectoBac® WDG or 12AS) up to four consecutive years. We examined the influence of both larvicide treatments and environmental variables on community dynamics and dissimilarity between treated and control areas. As it can be argued that chironomids are the most vulnerable group of non-target invertebrates, we scrutinised potential Bti-related effects on the dynamics of their community. The use of VectoBac® WDG and 12AS in coastal and continental wetlands had no immediate or long-term detectable effect on the taxonomic structure and taxa abundance of non-target aquatic invertebrate communities, including chironomids. This applied to the main habitats where mosquito larvae occur, regardless of their geographic location. Flooding, whose frequency and duration depend on local meteorological and hydrological conditions, was identified as the main environmental driver of invertebrate community dynamics. Our findings add support to the environmental safety of currently available Bti formulations when following recommended application rates and best mosquito control practices. Copyright © 2016 Elsevier B.V. All rights reserved.

Assessing sediments from Upper Mississippi River navigational pools using a benthic invertebrate community evaluation and the sediment quality triad approach

USGS Publications Warehouse

Canfield, T.J.; Brunson, E.L.; Dwyer, F.J.; Ingersoll, C.G.; Kemble, N.E.

1998-01-01

Benthic invertebrate samples were collected from 23 pools in the Upper Mississippi River (UMR) and from one station in the Saint Croix River (SCR) as part of a study to assess the effects of the extensive flooding of 1993 on sediment contamination in the UMR system. Sediment contaminants of concern included both organic and inorganic compounds. Oligochaetes and chironomids constituted over 80% of the total abundance in samples from 14 of 23 pools in the UMR and SCR samples. Fingernail clams comprised a large portion of the community in three of 23 UMR pools and exceeded abundances of 1,000/m2 in five of 23 pools. Total abundance ranged from 250/m2 in samples from pool 1 to 22,389/m2 in samples from pool 19. Abundance values are comparable with levels previously reported in the literature for the UMR. Overall frequency of chironomid mouthpart deformities was 3% (range 0-13%), which is comparable to reported incidence of deformities in uncontaminated sediments previously evaluated. Sediment contamination was generally low in the UMR pools and the SCR site. Correlations between benthic measures and sediment chemistry and other abiotic parameters exhibited few significant or strong correlations. The sediment quality triad (Triad) approach was used to evaluate data from laboratory toxicity tests, sediment chemistry, and benthic community analyses; it showed that 88% of the samples were not scored as impacted based on sediment toxicity, chemistry, and benthic measures. Benthic invertebrate distributions and community structure within the UMR in the samples evaluated in the present study were most likely controlled by factors independent of contaminant concentrations in the sediments.

Diet of the eastern mudminnow (Umbra pygmaea DeKay) from two geographically distinct populations within the North American native range

USGS Publications Warehouse

Panek, Frank M.; Weis, Judith S.

2013-01-01

Umbra pygmaea (Eastern Mudminnow) is a freshwater species common in Atlantic slope coastal lowlands from southern New York to northern Florida and is typical of slow-moving, mud-bottomed, and highly vegetated streams, swamps, and small ponds. We examined its seasonal food habits at the Great Swamp National Wildlife Refuge (NWR), NJ and at the Croatan National Forest, NC. A total of 147 Eastern Mudminnow from 35–112 mm TL and 190 Eastern Mudminnow from 22–89 mm TL were examined from these sites, respectively. At both locations, we found it to be a bottom-feeding generalist that consumes cladocerans, ostracods, chironomid larvae, coleopteran larvae, and other insects and crustaceans. Ostracods were most common in the diet at the Great Swamp NWR and occurred in 62% ± 2.5% of the stomachs with food. At Croatan National Forest, chironomid larvae were most common and occurred in 66.7% ± 15.8% of the stomachs. There were no statistically significant differences in diet composition between the sites during the winter, summer, and fall. However, when compared on an annual basis, Jaccard’s Index (θJ = 0.636, P = 0.05) suggested that the diet at the two study sites was significantly different. While we identified the same major food groups at both locations, the utilization of these food groups varied seasonally. Detritus was a major stomach content at both locations throughout the year. We also documented cannibalism during the summer season at both locations. The seasonal diet of the Eastern Mudminnow was similar to that of Umbra limi (Central Mudminnow) and Umbra krameri (European Mudminnow). Our findings here are the first quantitative examinations of seasonal differences in the diet of the Eastern Mudminnow within its native North American range.

Systematics and biogeography of the Gondwanan Orthocladiinae (Diptera: Chironomidae).

PubMed

Krosch, M N; Baker, A M; Mather, P B; Cranston, P S

2011-05-01

Restrictions to effective dispersal and gene flow caused by the fragmentation of ancient supercontinents are considered to have driven diversification and speciation on disjunct landmasses globally. Investigating the role that these processes have played in the development of diversity within and among taxa is crucial to understanding the origins and evolution of regional biotas. Within the chironomid (non-biting midge) subfamily Orthocladiinae (Diptera: Chironomidae), a group of genera that are distributed across the austral continents (Australia, New Zealand, South America) have been proposed to represent a relict Gondwanan clade. We used a molecular approach to resolve relationships among taxa with the aim to determine the relative roles that vicariance and dispersal may have played in the evolution of this group. Continental biotas did not form monophyletic groups, in accordance with expectations given existing morphological evidence. Patterns of phylogenetic relationships among taxa did not accord with expected patterns based on the geological sequence of break-up of the Gondwanan supercontinent. Likewise, divergence time estimates, particularly for New Zealand taxa, largely post-dated continental fragmentation and implied instead that several transoceanic dispersal events may have occurred post-vicariance. Passive dispersal of gravid female chironomid adults is the most likely mechanism for transoceanic movement, potentially facilitated by West Wind Drift or anti-cyclone fronts. Estimated timings of divergence among Australian and South American Botryocladius, on the other hand, were congruent with the proposed ages of separation of the two continents from Antarctica. Taken together, these data suggest that a complex relationship between both vicariance and dispersal may explain the evolution of this group. The sampling regime we implemented here was the most intensive yet performed for austral members of the Orthocladiinae and unsurprisingly revealed several novel taxa that will require formal description. Copyright © 2011 Elsevier Inc. All rights reserved.

Morphological and transcriptional response of an anhydrobiotic insect to ionizing radiation and desiccation: steps forward in understanding molecular background of extreme radioresistance in higher eukaryotes

NASA Astrophysics Data System (ADS)

Gusev, Oleg; Novikova, Nataliya; Sychev, Vladimir; Okuda, Takashi; Kikawada, Takahiro; Sakashita, Tetsuya; Mukae, Kyosuke

2012-07-01

Life in extreme or drastically changing environments in many cases leads to evolutionary evolvement of mechanisms of cross-resistance to different abiotic stresses, often never actually faced by the organism in its natural habitat. Larvae of the sleeping chironomidPolypedilum vanderplanki (Diptera) are able to resist complete desiccation and in the dry form survive under excess of various abiotic stresses, including exposure to space environment. One of the most intriguing features of the anhydrobiotic larvae is resistance to extremely high doses of different types of ionizing radiation. To understand the cross-tolerance mechanism, we have analyzed the structural changes in the nuclear DNA using transmission electron microscopy and DNA comet assays in relation to anhydrobiosis and radiation. We find that dehydration causes alterations in chromatin structure and a severe fragmentation of nuclear DNA in the cells of the larvae despite successful anhydrobiosis. The DNA fragmentation level and the recovery of DNA integrity in the rehydrated after anhydrobiosis larvae were similar to those of hydrated larvae irradiated with 70 Gy of high-linear energy transfer (LET) ions (4He+). In comparison, low-LET radiation (gamma rays) of the same dose causes less initial damage to the larvae, and recovery of DNA repair is complete within 24 h. Genome-wide analysis of mRNA expression in the larvae revealed that a large group of genes (including antioxidants, anhydrobiosis-specific biomolecules and protein-reparation enzymes) showed a similar patterns of activity in response to both desiccation and ionizing radiation. We conclude that t one of the factors explaining the relationship between the resistance to ionizing radiation and the ability to undergo anhydrobiosis in the sleeping chironomid would be an adaptation to desiccation-inflicted proteins and nuclear DNA damage.

Diversity of non-biting midge larvae assemblages in the Jacuí River basin, Brazil.

PubMed

Floss, Elzira Cecília Serafini; Kotzian, Carla Bender; Spies, Márcia Regina; Secretti, Elisangela

2012-01-01

The richness and composition of a mountain-river chironomid larvae assemblage in the Jacuí River basin, Brazil were studied, and compared with other riverine non-biting midge larvae assemblages previously studied in the country. Additionally, the influence of some regional-scale environmental characteristics on the spatial distribution of these assemblages was tested. The specimens were collected at 12 sites in the middle course of the Jacuí River basin (in the state of Rio Grande do Sul) between April 2000 and May 2002. Around 100 taxa were recorded. The dominant taxa belonged to the genera Rheotanytarsus, Cricotopus, Polypedilum, and Pseudochironomus. Twenty-two rare taxa were found, representing 22% of the total of taxa inventoried. Fourteen genera (Aedokritus, Axarus, Endotribelos, Kiefferulus, Manoa, Oukuriella, Phaenopsectra, Stenochironomus, Xenochironomus, Xestochironomus, Cardiocladius, Metriocnemus, Paracladius, and Rheocricotopus) represent new occurrences in Rio Grande do Sul. The similarity analysis of the chironomid larvae assemblages inventoried in 32 regions of Brazil indicated five groups with similarity higher than 50%. The groups, when the effects of spatial autocorrelation were removed, displayed a weak positive correlation between the assemblage composition and the aquatic system or hydraulic conditions and the hydrographic basin, and a weak negative correlation in relation to the biome. The altitude showed no correlation with the composition of the assemblage. The relatively high richness of the region surveyed in relation to other Brazilian regions corroborates some tendencies already noted in other parts of the world, such as: i) lotic systems may constitute an exception to the rule that diversity is greater in tropical regions, ii) regions of transitional relief may contain the greatest richness of Chironomidae, and iii) in rivers, the group might have its spatial distribution influenced to a greater extent by local environmental characteristics than by regional ones.

Seasonal Changes in Adult Longevity and Pupal Weight of the Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) with Implications for Interpreting Pheromone Trap Catch

Treesearch

Christopher Asaro; C. Wayne Berisford

2001-01-01

Pheromone trap catches of the Nantucket pine tip moth, Rhyacionia frustrana (Corn-stock), are often much higher during the first generation as compared with later generations, regardless of population density or damage levels. One hypothesis proposed to explain this phenomenon is reduced adult longevity during summer due to high temperatures. In this...

First Descriptions of Immature Stages of the Weevils Bagous elegans , B. aliciae , and B. lutulosus

PubMed Central

Gosik, Rafał; Wanat, Marek

2014-01-01

Abstract Last-instar larvae of Bagous elegans (F.), Bagous aliciae Cmoluch, and Bagous lutulosus (Gyllenhal), and the pupa of B . elegans , are described and illustrated for the first time. Biology of these species is analyzed in association with larval morphology and feeding habits. Overall larval and pupal morphological diagnoses of the genus Bagous are updated. PMID:25347832

Preliminary results on predation of gypsy moth pupae during a period of latency in Slovakia

Treesearch

Marek Turcani; Andrew M. Liebhold; Michael McManus; J& #250; lius Novotn& #253

2003-01-01

Predation of gypsy moth pupae was studied from 2000 -2003 in Slovakia. Predation on artificially reared pupae was recorded and linear regression was used to test the hypothesis that predation follows a type II vs. type III functional response. The role of pupal predation in gypsy moth population dynamics was also investigated. The relative importance of predation of...

Evaluation of the Mating Competitiveness of the Adult Oriental Fruit Fly Reared as Larvae in Liquid vs. Those Raised on Standard Wheat-based Diets

USDA-ARS?s Scientific Manuscript database

Three strains (standard lab, DTWP pupal color sexing strain and wild strain) of adult oriental fruit flies, which were reared as larvae on a liquid diet, mill feed diet (Tanaka’s diet), or natural host fruit diet, were evaluated for mating competitiveness in both indoor and outdoor Boller’s mating c...

Development of the teneral adult Anoplophora glabripennis (Coleoptera: Cerambycidae): time to initiate and completely bore out of maple wood

Treesearch

V. Sanchez; M.A. Keena

2013-01-01

Anoplophora glabripennis (Motschulsky) is an introduced invasive pest with the potential to devastate hardwood forests in North America. Using artificial pupal chambers, we documented the time required by teneral adults at three temperatures (20, 25, and 30°C), 60-80% RH, and a photoperiod of 16:8 (L:D) h to initiate boring after eclosion...

Simulium (Phosterodoros) penobscotensis, a new species of black fly (Diptera: Simuliidae) from Maine, U.S.A.

Treesearch

Edward L. Snoddy; Leah S. Bauer

1978-01-01

A new species of black fly, Simulium penobscotensis, is described from tributaries of the Penobscot River, Maine, U.S.A. This species is a major late-season biting pest of man. Adults are similar to other members of the subgenus Phosterodoros, but the larvae and pupae are quite distinct. The pupal cocoon is unique because it has a...

Biology and reproductive parameters of the brown lygodium moth, Neomusotima conspurcatalis - a new biological control agent of Old World climbing fern in Florida

USDA-ARS?s Scientific Manuscript database

The average duration of the egg, larval and pupal stage of Neomusotima conspurcatalis (Lepidoptera: Crambidae) at 25oC was 7, 10, and 5 days respectively. Larvae generally molted through five instars. The sex ratio was male-biased, averaging 1:0.8 (':'). Both sexes emerged at the same time. Female m...

Arylalkylamine N-acetyltransferase 1 gene (TcAANAT1) is required for cuticle morphology and pigmentation of the adult red flour beetle, Tribolium castaneum.

PubMed

Noh, Mi Young; Koo, Bonwoo; Kramer, Karl J; Muthukrishnan, Subbaratnam; Arakane, Yasuyuki

2016-12-01

In the insect cuticle tanning pathway (sclerotization and pigmentation), the enzyme arylalkylamine N-acetyltransferase (AANAT) catalyzes the acetylation of dopamine to form N-acetyldopamine (NADA), which is one of the major precursors for quinone-mediated tanning. In this study we characterized and investigated the function of TcAANAT1 in cuticle pigmentation of the red flour beetle, Tribolium castaneum. We isolated a full length TcAANAT1 cDNA that encodes a protein of 256 amino acid residues with a predicted GCN5-related acetyltransferase domain containing an acetyl-CoA binding motif. TcAANAT1 transcripts were detected at all stages of development with lowest expressions at the embryonic and pharate pupal stages. We expressed and purified the encoded recombinant TcAANAT1 protein (rTcAANAT1) that exhibited highest activity at slightly basic pH values (for example, pH 7.5 to 8.5 using dopamine as the substrate). In addition, rTcAANAT1 acts on a wide range of substrates including tryptamine, octopamine and norepinephrine with similar substrate affinities with K m values in the range of 0.05-0.11 mM except for tyramine (K m  = 0.56 mM). Loss of function of TcAANAT1 caused by RNAi had no effect on larval and pupal development. The tanning of pupal setae, gin traps and urogomphi proceeded normally. However, the resulting adults (∼70%) exhibited a roughened exoskeletal surface, separated elytra and improperly folded hindwings. The body wall, elytra and veins of the hindwing of the mature adults were significantly darker than those of control insects probably due to the accumulation of dopamine melanin. A dark pigmentation surrounding the bristles located on the inter-veins of the elytron was evident primarily because of the underlying darkly pigmented trabeculae that partition the dorsal and ventral layers of the elytron. These results support the hypothesis that TcAANAT1 acetylates dopamine and plays a role in development of the morphology and pigmentation of T. castaneum adult cuticle. Copyright © 2016 Elsevier Ltd. All rights reserved.

Pupal productivity in rainy and dry seasons: findings from the impact survey of a randomised controlled trial of dengue prevention in Guerrero, Mexico.

PubMed

Jiménez-Alejo, Abel; Morales-Pérez, Arcadio; Nava-Aguilera, Elizabeth; Flores-Moreno, Miguel; Apreza-Aguilar, Sinahí; Carranza-Alcaraz, Wilhelm; Cortés-Guzmán, Antonio Juan; Fernández-Salas, Ildefonso; Ledogar, Robert J; Cockcroft, Anne; Andersson, Neil

2017-05-30

The follow-up survey of a cluster-randomised controlled trial of evidence-based community mobilisation for dengue control in Nicaragua and Mexico included entomological information from the 2012 rainy and dry seasons. We used data from the Mexican arm of the trial to assess the impact of the community action on pupal production of the dengue vector Aedes aegypti in both rainy and dry seasons. Trained field workers inspected household water containers in 90 clusters and collected any pupae or larvae present for entomological examination. We calculated indices of pupae per person and pupae per household, and traditional entomological indices of container index, household index and Breteau index, and compared these between rainy and dry seasons and between intervention and control clusters, using a cluster t-test to test significance of differences. In 11,933 houses in the rainy season, we inspected 40,323 containers and found 7070 Aedes aegypti pupae. In the dry season, we inspected 43,461 containers and counted 6552 pupae. All pupae and entomological indices were lower in the intervention clusters (IC) than in control clusters (CC) in both the rainy season (RS) and the dry season (DS): pupae per container 0.12 IC and 0.24 CC in RS, and 0.10 IC and 0.20 CC in DS; pupae per household 0.46 IC and 0.82 CC in RS, and 0.41 IC and 0.83 CC in DS; pupae per person 0.11 IC and 0.19 CC in RS, and 0.10 IC and 0.20 CC in DS; household index 16% IC and 21% CC in RS, and 12.1% IC and 17.9% CC in DS; container index 7.5% IC and 11.5% CC in RS, and 4.6% IC and 7.1% CC in DS; Breteau index 27% IC and 36% CC in RS, and 19% IC and 29% CC in DS. All differences between the intervention and control clusters were statistically significant, taking into account clustering. The trial intervention led to significant decreases in pupal and conventional entomological indices in both rainy and dry seasons. ISRCTN27581154 .

Looking into the puparium: Micro‐CT visualization of the internal morphological changes during metamorphosis of the blow fly, Calliphora vicina, with the first quantitative analysis of organ development in cyclorrhaphous dipterans

PubMed Central

Simonsen, Thomas J.; Hall, Martin J. R.

2017-01-01

Abstract Metamorphosis of cyclorrhaphous flies takes place inside a barrel‐like puparium, formed by the shrinking, hardening and darkening of the third‐instar larval cuticle. The opacity of this structure hampers the visualization of the morphological changes occurring inside and therefore a full understanding of the metamorphosis process. Here, we use micro‐computed tomography (micro‐CT) to describe the internal morphological changes that occur during metamorphosis of the blow fly, Calliphora vicina Robineau‐Desvoidy 1830 (Diptera: Calliphoridae) at a greater temporal resolution than anything hitherto published. The morphological changes were documented at 10% intervals of the total intra‐puparial period, and down to 2.5% intervals during the first 20% interval, when the most dramatic morphological changes occur. Moreover, the development of an internal gas bubble, which plays an essential role during early metamorphosis, was further investigated with X‐ray images and micro‐CT virtual sections. The origin of this gas bubble has been largely unknown, but micro‐CT virtual sections show that it is connected to one of the main tracheal trunks. Micro‐CT virtual sections also provided enough resolution for determining the completion of the larval‐pupal and pupal‐adult apolyses, thus enabling an accurate timing of the different intra‐puparial life stages. The prepupal, pupal, and pharate adult stages last for 7.5%, 22.5%, and 70% of the total intra‐puparial development, respectively. Furthermore, we provide for the first time quantitative data on the development of two organ systems of the blow fly: the alimentary canal and the indirect flight muscles. There is a significant and negative correlation between the volume of the indirect flight muscles and the pre‐helicoidal region of the midgut during metamorphosis. The latter occupies a large portion of the thorax during the pupal stage but narrows progressively as the indirect flight muscles increase in volume during the development of the pharate adult. PMID:28182298

Baculovirus-mediated gene transfer in butterfly wings in vivo: an efficient expression system with an anti-gp64 antibody

PubMed Central

2013-01-01

Background Candidate genes for color pattern formation in butterfly wings have been known based on gene expression patterns since the 1990s, but their functions remain elusive due to a lack of a functional assay. Several methods of transferring and expressing a foreign gene in butterfly wings have been reported, but they have suffered from low success rates or low expression levels. Here, we developed a simple, practical method to efficiently deliver and express a foreign gene using baculovirus-mediated gene transfer in butterfly wings in vivo. Results A recombinant baculovirus containing a gene for green fluorescent protein (GFP) was injected into pupae of the blue pansy butterfly Junonia orithya (Nymphalidae). GFP fluorescence was detected in the pupal wings and other body parts of the injected individuals three to five days post-injection at various degrees of fluorescence. We obtained a high GFP expression rate at relatively high virus titers, but it was associated with pupal death before color pattern formation in wings. To reduce the high mortality rate caused by the baculovirus treatment, we administered an anti-gp64 antibody, which was raised against baculovirus coat protein gp64, to infected pupae after the baculovirus injection. This treatment greatly reduced the mortality rate of the infected pupae. GFP fluorescence was observed in pupal and adult wings and other body parts of the antibody-treated individuals at various degrees of fluorescence. Importantly, we obtained completely developed wings with a normal color pattern, in which fluorescent signals originated directly from scales or the basal membrane after the removal of scales. GFP fluorescence in wing tissues spatially coincided with anti-GFP antibody staining, confirming that the fluorescent signals originated from the expressed GFP molecules. Conclusions Our baculovirus-mediated gene transfer system with an anti-gp64 antibody is reasonably efficient, and it can be an invaluable tool to transfer, express, and functionally examine foreign genes in butterfly wings and also in other non-model insect systems. PMID:23522444

MicroRNA expression profiling during the life cycle of the silkworm (Bombyx mori)

PubMed Central

Liu, Shiping; Zhang, Liang; Li, Qibin; Zhao, Ping; Duan, Jun; Cheng, Daojun; Xiang, Zhonghuai; Xia, Qingyou

2009-01-01

Background MicroRNAs (miRNAs) are expressed by a wide range of eukaryotic organisms, and function in diverse biological processes. Numerous miRNAs have been identified in Bombyx mori, but the temporal expression profiles of miRNAs corresponding to each stage transition over the entire life cycle of the silkworm remain to be established. To obtain a comprehensive overview of the correlation between miRNA expression and stage transitions, we performed a whole-life test and subsequent stage-by-stage examinations on nearly one hundred miRNAs in the silkworm. Results Our results show that miRNAs display a wide variety of expression profiles over the whole life of the silkworm, including continuous expression from embryo to adult (miR-184), up-regulation over the entire life cycle (let-7 and miR-100), down-regulation over the entire life cycle (miR-124), expression associated with embryogenesis (miR-29 and miR-92), up-regulation from early 3rd instar to pupa (miR-275), and complementary pulses in expression between miR-34b and miR-275. Stage-by-stage examinations revealed further expression patterns, such as emergence at specific time-points during embryogenesis and up-regulation of miRNA groups in late embryos (miR-1 and bantam), expression associated with stage transition between instar and molt larval stages (miR-34b), expression associated with silk gland growth and spinning activity (miR-274), continuous high expression from the spinning larval to pupal and adult stages (miR-252 and miR-31a), a coordinate expression trough in day 3 pupae of both sexes (miR-10b and miR-281), up-regulation in pupal metamorphosis of both sexes (miR-29b), and down-regulation in pupal metamorphosis of both sexes (miR-275). Conclusion We present the full-scale expression profiles of miRNAs throughout the life cycle of Bombyx mori. The whole-life expression profile was further investigated via stage-by-stage analysis. Our data provide an important resource for more detailed functional analysis of miRNAs in this animal. PMID:19785751

MicroRNA expression profiling during the life cycle of the silkworm (Bombyx mori).

PubMed

Liu, Shiping; Zhang, Liang; Li, Qibin; Zhao, Ping; Duan, Jun; Cheng, Daojun; Xiang, Zhonghuai; Xia, Qingyou

2009-09-28

MicroRNAs (miRNAs) are expressed by a wide range of eukaryotic organisms, and function in diverse biological processes. Numerous miRNAs have been identified in Bombyx mori, but the temporal expression profiles of miRNAs corresponding to each stage transition over the entire life cycle of the silkworm remain to be established. To obtain a comprehensive overview of the correlation between miRNA expression and stage transitions, we performed a whole-life test and subsequent stage-by-stage examinations on nearly one hundred miRNAs in the silkworm. Our results show that miRNAs display a wide variety of expression profiles over the whole life of the silkworm, including continuous expression from embryo to adult (miR-184), up-regulation over the entire life cycle (let-7 and miR-100), down-regulation over the entire life cycle (miR-124), expression associated with embryogenesis (miR-29 and miR-92), up-regulation from early 3rd instar to pupa (miR-275), and complementary pulses in expression between miR-34b and miR-275. Stage-by-stage examinations revealed further expression patterns, such as emergence at specific time-points during embryogenesis and up-regulation of miRNA groups in late embryos (miR-1 and bantam), expression associated with stage transition between instar and molt larval stages (miR-34b), expression associated with silk gland growth and spinning activity (miR-274), continuous high expression from the spinning larval to pupal and adult stages (miR-252 and miR-31a), a coordinate expression trough in day 3 pupae of both sexes (miR-10b and miR-281), up-regulation in pupal metamorphosis of both sexes (miR-29b), and down-regulation in pupal metamorphosis of both sexes (miR-275). We present the full-scale expression profiles of miRNAs throughout the life cycle of Bombyx mori. The whole-life expression profile was further investigated via stage-by-stage analysis. Our data provide an important resource for more detailed functional analysis of miRNAs in this animal.

Insect growth regulatory activity of Vitex trifolia and Vitex agnus-castus essential oils against Spilosoma obliqua.

PubMed

Tandon, Shishir; Mittal, Ashutosh K; Pant, A K

2008-06-01

Essential oils of Vitex trifolia and Vitex agnus-castus were evaluated against Vth instar larvae of Spilosoma obliqua, when applied topically on the dorsal side of mesothoracic region, for insect growth regulatory activity. This treatment caused extended larval period and pupal period, increase in larval mortality and adult deformity and decrease in adult emergence, fecundity of female and egg fertility of test insect.

Simulium hiroyukii, a new species of the subgenus Gomphostilbia (Diptera: Simuliidae) from Mount Murud, Sarawak, Malaysia.

PubMed

Ya'cob, Zubaidah; Takaoka, Hiroyuki; Sofian-Azirun, Mohd

2015-01-20

Simulium (Gomphostilbia) hiroyukii is described based on females, males, pupae and larvae collected in Mount Murud, Sarawak, Malaysia. This new species is assigned to the Simulium darjeelingense species-group of the subgenus Gomphostilbia, and is characterized by the darkened fore coxae and the pupal gill with eight long filaments, of which middle and dorsal triplets have elongated primary and secondary stalks, respectively. 

Label-free imaging of Drosophila in vivo by coherent anti-Stokes Raman scattering and two-photon excitation autofluorescence microscopy

NASA Astrophysics Data System (ADS)

Chien, Cheng-Hao; Chen, Wei-Wen; Wu, June-Tai; Chang, Ta-Chau

2011-01-01

Drosophila is one of the most valuable model organisms for studying genetics and developmental biology. The fat body in Drosophila, which is analogous to the liver and adipose tissue in human, stores lipids that act as an energy source during its development. At the early stages of metamorphosis, the fat body remodeling occurs involving the dissociation of the fat body into individual fat cells. Here we introduce a combination of coherent anti-Stokes Raman scattering (CARS) and two-photon excitation autofluorescence (TPE-F) microscopy to achieve label-free imaging of Drosophila in vivo at larval and pupal stages. The strong CARS signal from lipids allows direct imaging of the larval fat body and pupal fat cells. In addition, the use of TPE-F microscopy allows the observation of other internal organs in the larva and autofluorescent globules in fat cells. During the dissociation of the fat body, the findings of the degradation of lipid droplets and an increase in autofluorescent globules indicate the consumption of lipids and the recruitment of proteins in fat cells. Through in vivo imaging and direct monitoring, CARS microscopy may help elucidate how metamorphosis is regulated and study the lipid metabolism in Drosophila.

Plant Fertilization Interacts with Life History: Variation in Stoichiometry and Performance in Nettle-Feeding Butterflies

PubMed Central

Audusseau, Hélène; Kolb, Gundula; Janz, Niklas

2015-01-01

Variation in food stoichiometry affects individual performance and population dynamics, but it is also likely that species with different life histories should differ in their sensitivity to food stoichiometry. To address this question, we investigated the ability of the three nettle-feeding butterflies (Aglais urticae, Polygonia c-album, and Aglais io) to respond adaptively to induced variation in plant stoichiometry in terms of larval performance. We hypothesized that variation in larval performance between plant fertilization treatments should be functionally linked to species differences in host plant specificity. We found species-specific differences in larval performance between plant fertilization treatments that could not be explained by nutrient limitation. We showed a clear evidence of a positive correlation between food stoichiometry and development time to pupal stage and pupal mass in A. urticae. The other two species showed a more complex response. Our results partly supported our prediction that host plant specificity affects larval sensitivity to food stoichiometry. However, we suggest that most of the differences observed may instead be explained by differences in voltinism (number of generations per year). We believe that the potential of some species to respond adaptively to variation in plant nutrient content needs further attention in the face of increased eutrophication due to nutrient leakage from human activities. PMID:25932628

Plant fertilization interacts with life history: variation in stoichiometry and performance in nettle-feeding butterflies.

PubMed

Audusseau, Hélène; Kolb, Gundula; Janz, Niklas

2015-01-01

Variation in food stoichiometry affects individual performance and population dynamics, but it is also likely that species with different life histories should differ in their sensitivity to food stoichiometry. To address this question, we investigated the ability of the three nettle-feeding butterflies (Aglais urticae, Polygonia c-album, and Aglais io) to respond adaptively to induced variation in plant stoichiometry in terms of larval performance. We hypothesized that variation in larval performance between plant fertilization treatments should be functionally linked to species differences in host plant specificity. We found species-specific differences in larval performance between plant fertilization treatments that could not be explained by nutrient limitation. We showed a clear evidence of a positive correlation between food stoichiometry and development time to pupal stage and pupal mass in A. urticae. The other two species showed a more complex response. Our results partly supported our prediction that host plant specificity affects larval sensitivity to food stoichiometry. However, we suggest that most of the differences observed may instead be explained by differences in voltinism (number of generations per year). We believe that the potential of some species to respond adaptively to variation in plant nutrient content needs further attention in the face of increased eutrophication due to nutrient leakage from human activities.

Influence of Pupation Substrate on Mass Production and Fitness of Adult Anastrepha obliqua Macquart (Diptera: Tephritidae) for Sterile Insect Technique Application.

PubMed

Aceituno-Medina, Marysol; Rivera-Ciprian, José Pedro; Hernández, Emilio

2017-12-05

Tephritid mass-rearing systems require an artificial substrate for pupation. Pupation substrate characteristics influence the quality of insects produced. Coconut fiber, as an alternative to the conventional pupation substrate vermiculite, was evaluated for Anastrepha obliqua Macquart (Diptera: Tephritidae) pupation behavior (pupation patterns, distribution, respiration rate, and pupal weight) and adult fitness (adult eclosion time, flight ability, and male mating competitiveness). Pupation percentage at 24 h, pupal weight, and flight ability were not significantly affected by substrate type. Adult eclosion levels of 50% were reached at 29.7 and 41.6 h for coconut fiber and vermiculite, respectively. Pupae distribution patterns differed between substrates because the larval aggregation level was reduced during the pupation process in coconut fiber. The pupae aggregation was three times greater in vermiculite than in coconut fiber. A higher respiratory rate in the last days of pupation and adult eclosion were recorded in the insects maintained in coconut fiber. Coconut fiber suitability as a pupation substrate for quality mass production of pupae and its implications for sterile insect technique are discussed. © The Author(s) 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.

Imaging the Drosophila retina: zwitterionic buffers PIPES and HEPES induce morphological artifacts in tissue fixation.

PubMed

Nie, Jing; Mahato, Simpla; Zelhof, Andrew C

2015-02-03

Tissue fixation is crucial for preserving the morphology of biological structures and cytological details to prevent postmortem degradation and autolysis. Improper fixation conditions could lead to artifacts and thus incorrect conclusions in immunofluorescence or histology experiments. To resolve reported structural anomalies with respect to Drosophila photoreceptor cell organization we developed and utilized a combination of live imaging and fixed samples to investigate the exact biogenesis and to identify the underlying source for the reported discrepancies in structure. We found that piperazine-N,N'-bis(ethanesulfonic acid) (PIPES) and 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), two zwitterionic buffers commonly used in tissue fixation, can cause severe lumen and cell morphological defects in Drosophila pupal and adult retina; the inter-rhabdomeral lumen becomes dilated and the photoreceptor cells are significantly reduced in size. Correspondingly, the localization pattern of Eyes shut (EYS), a luminal protein, is severely altered. In contrast, tissues fixed in the phosphate buffered saline (PBS) buffer results in lumen and cell morphologies that are consistent with live imaging. We suggest that PIPES and HEPES buffers should be utilized with caution for fixation when examining the interplay between cells and their extracellular environment, especially in Drosophila pupal and adult retina research.

Prolonged pupal dormancy is associated with significant fitness cost for adults of Rhagoletis cerasi (Diptera: Tephritidae).

PubMed

Moraiti, Cleopatra A; Nakas, Christos T; Papadopoulos, Nikos T

2012-08-01

In temperate areas, dormancy (diapause and/or quiescence) enables herbivorous insect species to persist and thrive by synchronizing growth and reproduction with the seasonal phenology of their host plants. Within-population variability in dormancy increases survival chances under unpredictable environmental changes. However, prolonged dormancy may be costly, incurring trade-offs in important adult fitness traits such as life span and reproduction. We used the European cherry fruit fly, Rhagoletis cerasi, a stenophagous, univoltine species that overwinters in the pupal stage for usually one or more years to test the hypotheses that prolonged dormancy of pupae has trade-offs with body size, survival and reproduction of the resulting adults. We used two geographically isolated populations of R. cerasi to compare the demographic traits of adults obtained from pupae subjected to one or two cycles of warm-cold periods (annual and prolonged dormancy respectively). Regardless of population, adults from pupae that experienced prolonged dormancy were larger than counterparts emerging within 1year. Prolonged dormancy did not affect adult longevity but both lifetime fecundity and oviposition were significantly decreased. Extension of the life cycle of some individuals in R. cerasi populations in association with prolonged dormancy is likely a bet-hedging strategy. Copyright © 2012 Elsevier Ltd. All rights reserved.

Leg deformation during imaginal ecdysis in the downy emerald, Cordulia aenea (Odonata, Corduliidae).

PubMed

Frantsevich, Leonid; Frantsevich, Ludmilla

2018-04-01

A dragonfly larva migrates from the water to the shore, perches on a plant stem and grasps it with strongly flexed legs. Adult legs inside the larval exoskeleton fit to the larval legs joint-to-joint. The adult emerges with stretched legs. During the molt, an imaginal leg must follow all the angles in exuvial joints. In turn, larval apodemes are withdrawn from imaginal legs. We visualized transient shapes of the imaginal legs by the instant fixation of insects at different moments of the molt, photographed isolated exuvial legs with the imaginal legs inside and then removed the exuvial sheath. Instant shapes of the imaginal tibia show sharp intrapodomere bends copying the angle in the larval femoro-tibial joint. The site of bending shifts distad during the molt. This is possible if the imaginal leg is pliable. The same problem of leg squeezing is also common in hemimetabolous insects as well as in other arthropods, whereas holometabolous insects overcome problems of a tight confinement either by using leg pliability in other ways but not squeezing (cyclorrhaphan flies, mosquitoes) or by pulling hardened legs out without change of their pupal zigzag configuration (moths, ants, honey bees). The pupal legs are not intended to grasp any external substrate. Copyright © 2018 Elsevier GmbH. All rights reserved.

Lethal and sublethal effects of chlorantraniliprole on Spodoptera cosmioides (Lepidoptera: Noctuidae).

PubMed

Lutz, Alejandra L; Bertolaccini, Isabel; Scotta, Roberto R; Curis, María C; Favaro, María A; Fernandez, Laura N; Sánchez, Daniel E

2018-05-16

Spodoptera cosmioides (Walker, 1858) population has increased in Bt soybean crops in Argentina. As there are no registered products for its control, the recommended insecticides for S. frugiperda are used. The aim of this study was therefore to determine the lethal concentration (LC) and sublethal effects of chlorantraniliprole on the biological and reproductive functions of S. cosmioides, an emerging soybean pest in Argentina. An ingestion toxicity bioassay showed that chlorantraniliprole was active against larvae of the second instar, and after 48 h exposure LC50 was 0.054 μg/ml H2O. In the study of sublethal effect, chlorantraniliprole induced changes in the life cycle of exposed S. cosmioides, which required more time to complete all stages of development (larval, pupal and adult stages). Pupal weight was also higher in larvae exposed to sublethal concentrations of chlorantraniliprole. Adult fecundity was decreased: the number of eggs laid by each adult female moth, as compared to control females, was two (LC 15 ) and eight (LC 30 ) times smaller. These results indicate that chlorantraniliprole has toxicity against S. cosmioides larvae. Sublethal effects on the biological and reproductive performance of this species can help optimize integrated pest management programs. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Ecdysis period and rate deviations of dengue mosquito vector, Aedes aegypti reared in different artificial water-holding containers.

PubMed

Almanzor, Beatriz Louise J; Ho, Howell T; Carvajal, Thaddeus M

2016-03-01

Artificial water-holding containers (AWHCs) have been well-documented in many Aedes aegypti studies for dengue surveillance and developmental research. Hence, we investigated the role of different AHWCs on the development and ecdysis period of Ae. aegypti dengue vector, a container breeding mosquito. Nine types of AWHCs, namely glass, polystyrene foam, rubber, steel, porcelain, plastic, aluminum, clay and concrete, were chosen for the study. All AWHCs were subjected to the developmental assay for an observation period of 10 days. Regression and hazard analyses were employed to the developmental stages and the characteristics of the AWHCs. The observations revealed that Ae. aegypti development is fastest in glass and polystyrene containers while slowest in concrete containers. Moreover, pupal ecdysis appears to be the most affected by the characteristics of the AWHCs based on regression and hazard analyses. Characteristics of the container that can regulate water temperature seem to be the driving force with regards to the slow or fast development of Ae. aegypti, more notably in pupal ecdysis. The results of the study further strengthen our understanding on the dynamics of Ae. aegypti's developmental biology to different characteristics of artificial water containers. This, in turn, would aid in devising vector control strategies against dengue especially in endemic areas.

Yorkie Facilitates Organ Growth and Metamorphosis in Bombyx

PubMed Central

Liu, Shumin; Zhang, Panli; Song, Hong-Sheng; Qi, Hai-Sheng; Wei, Zhao-Jun; Zhang, Guozheng; Zhan, Shuai; Liu, Zhihong; Li, Sheng

2016-01-01

The Hippo pathway, which was identified from genetic screens in the fruit fly, Drosophila melanogaster, has a major size-control function in animals. All key components of the Hippo pathway, including the transcriptional coactivator Yorkie that is the most critical substrate and downstream effector of the Hippo kinase cassette, are found in the silkworm, Bombyx mori. As revealed by microarray and quantitative real-time PCR, expression of Hippo pathway genes is particularly enriched in several mitotic tissues, including the ovary, testis, and wing disc. Developmental profiles of Hippo pathway genes are generally similar (with the exception of Yorkie) within each organ, but vary greatly in different tissues showing nearly opposing expression patterns in the wing disc and the posterior silk gland (PSG) on day 2 of the prepupal stage. Importantly, the reduction of Yorkie expression by RNAi downregulated Yorkie target genes in the ovary, decreased egg number, and delayed larval-pupal-adult metamorphosis. In contrast, baculovirus-mediated YorkieCA overexpression upregulated Yorkie target genes in the PSG, increased PSG size, and accelerated larval-pupal metamorphosis. Together the results show that Yorkie potentially facilitates organ growth and metamorphosis, and suggest that the evolutionarily conserved Hippo pathway is critical for size control, particularly for PSG growth, in the silkworm. PMID:27489496

Summer diapause induced by high temperatures in the oriental tobacco budworm: ecological adaptation to hot summers.

PubMed

Liu, Zhudong; Xin, Yucui; Zhang, Yanan; Fan, Jianting; Sun, Jianghua

2016-06-07

Summer diapause in Helicoverpa assulta (Hübner), which prolongs the pupal stage, particularly in males, is induced by high temperatures. In the laboratory, 3(rd)-, 4(th)-, 6(th)-instar and prepupal larvae were exposed to high temperatures - 33 and 35 °C with a photoperiod of LD16:8 - until pupation to induce summer diapause. The results showed that the incidence of summer diapause was influenced by temperature, stage exposed, and sex. The higher the temperature, the more often summer diapause was attained. Sixth-instar and prepupal larvae were the sensitive stages for summer diapause induction. H. assulta summer-diapausing pupae needed diapause development to resume development when temperatures became favorable. Furthermore, both body mass and energy storage capacity (lipid and glycogen) were significantly affected by diapause rather than sex, and were significantly higher in summer-diapausing pupae than in non-diapausing pupae. In addition, the body mass loss and respiration rate showed that the rate of metabolism in the summer-diapausing pupae was consistently lower than in non-diapausing pupae, which were significantly affected by diapause and pupal age. We conclude that summer diapause in H. assulta is a true diapause, and H. assulta has evolved mechanisms to accumulate energy storage and to lower its metabolism to adapt to hot summers.

Further Screening of Entomopathogenic Fungi and Nematodes as Control Agents for Drosophila suzukii.

PubMed

Cuthbertson, Andrew G S; Audsley, Neil

2016-06-09

Drosophila suzukii populations remain low in the UK. To date, there have been no reports of widespread damage. Previous research demonstrated that various species of entomopathogenic fungi and nematodes could potentially suppress D. suzukii population development under laboratory trials. However, none of the given species was concluded to be specifically efficient in suppressing D. suzukii. Therefore, there is a need to screen further species to determine their efficacy. The following entomopathogenic agents were evaluated for their potential to act as control agents for D. suzukii: Metarhizium anisopliae; Isaria fumosorosea; a non-commercial coded fungal product (Coded B); Steinernema feltiae, S. carpocapsae, S. kraussei and Heterorhabditis bacteriophora. The fungi were screened for efficacy against the fly on fruit while the nematodes were evaluated for the potential to be applied as soil drenches targeting larvae and pupal life-stages. All three fungi species screened reduced D. suzukii populations developing from infested berries. Isaria fumosorosea significantly (p < 0.001) reduced population development of D. suzukii from infested berries. All nematodes significantly reduced adult emergence from pupal cases compared to the water control. Larvae proved more susceptible to nematode infection. Heterorhabditis bacteriophora proved the best from the four nematodes investigated; readily emerging from punctured larvae and causing 95% mortality. The potential of the entomopathogens to suppress D. suzukii populations is discussed.

Effects of Aqueous Extracts of Copaifera langsdorffii (Fabaceae) on the Growth and Reproduction of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae).

PubMed

Sâmia, R R; de Oliveira, R L; Moscardini, V F; Carvalho, G A

2016-10-01

Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is considered a pest of maize crops throughout the Western Hemisphere. We report on the effects of aqueous extracts of leaves and bark of Copaifera langsdorffii (Fabaceae) on the biology of S. frugiperda, as an alternative source of natural bioactive molecules for the sustainable management of this pest. Second instars were sprayed with aqueous extracts prepared with 5% (w/v) plant material and/or fed on an artificial diet containing extracts at a concentration equivalent to 0.25% (w/v) for 17 days. Both leaf and bark extracts of C. langsdorffii significantly reduced S. frugiperda food intake, feces, and larval weight and caused a delay in larval development. Additionally, C. langsdorffii-based extracts increased the oviposition period; induced morphological changes in the eggs, including deformation of the corium and malformation of the micropylar and aeropylar regions; and reduced egg viability. But, aqueous extracts of C. langsdorffii exhibited no negative effects on larval and pupal survival, duration of the pupal stage, survival of pupae, sex ratio, longevity, duration of pre-oviposition period, and female fecundity. Aqueous extracts of leaves and bark of C. langsdorffii are promising alternatives for the control of S. frugiperda in maize crops.

Developmental and Digestive Flexibilities in the Midgut of a Polyphagous Pest, the Cotton Bollworm, Helicoverpa armigera

PubMed Central

Sarate, P.J.; Tamhane, V.A.; Kotkar, H.M.; Ratnakaran, N.; Susan, N.; Gupta, V.S.; Giri, A.P.

2012-01-01

Developmental patterns and survival of the cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), a polyphagous insect pest, have been studied with reference to the effect of diet on major gut digestive enzymes (amylases, proteases, and lipases). Significant correlations between nutritional quality of the diet and larval and pupal mass were observed when H. armigera larvae were fed on various host plants viz. legumes (chickpea and pigeonpea), vegetables (tomato and okra), flowers (rose and marigold), and cereals (sorghum and maize). Larvae fed on diets rich in proteins and/or carbohydrates (pigeonpea, chickpea, maize, and sorghum) showed higher larval mass and developed more rapidly than larvae fed on diets with low protein and carbohydrate content (rose, marigold, okra, and tomato). Low calorific value diets like rose and marigold resulted in higher mortality (25–35%) of H. armigera. Even with highly varying development efficiency and larval/pupal survival rates, H. armigera populations feeding on different diets completed their life cycles. Digestive enzymes of H. armigera displayed variable expression levels and were found to be regulated on the basis of macromolecular composition of the diet. Post—ingestive adaptations operating at the gut level, in the form of controlled release of digestive enzymes, might be a key factor contributing to the physiological plasticity in H. armigera. PMID:22954360

Natural enemies of Atta vollenweideri (Hymenoptera: Formicidae) leaf-cutter ants negatively affected by synthetic pesticides, chlorpyrifos and fipronil.

PubMed

Guillade, Andrea C; Folgarait, Patricia J

2014-02-01

In southern South America, Ada vollenweideri Forel (Hymenoptera: Formicidae) is a significant pest of several crops and forestry, also considered to reduce the carrying capacity of pastures. The most usual control method used in Latin America is the application of synthetic pesticides, mainly chlorpyrifos and fipronil. However, no studies have assessed the effects of these agrochemicals on natural enemies of ants. We aimed to evaluate the efficiency of these pesticides on leaf-cutter ants' control and to test their effect on phorid fly parasitoids. Chlorpyrifos failed to exert complete control over ant colonies in the field and was gravely detrimental to specific parasitoids, reducing their percentage of parasitism, pupal survivorship, and adult longevity. Fipronil, however, exerted complete control over the treated colonies. Laboratory tests using both pesticides, either on ants from foraging trails or on pupariae, showed that chlorpyrifos and fipronil decreased larval and pupal survivorship, as well as adult longevity of parasitoids, in comparison to controls. In conclusion, these pesticides will likely affect parasitoids with regard to their reproductive capacity, leading to the decreased levels of natural parasitism observed in the field after treatments. We discuss why neither pesticide should be taken into account for integrated pest management programs.

Angiotensin-converting enzyme in Spodoptera littoralis: molecular characterization, expression and activity profile during development.

PubMed

Lemeire, Els; Vanholme, Bartel; Van Leeuwen, Thomas; Van Camp, John; Smagghe, Guy

2008-02-01

The characterization of the full-length angiotensin-converting enzyme (ACE) cDNA sequence of the lepidopteran Spodoptera littoralis is reported in this study. The predicted open reading frame encodes a 647 amino acids long protein (SlACE) and shows 63.6% identity with the Bombyx mori ACE sequence. A 3D-model, consisting of 26 alpha-helices and three beta-sheets, was predicted for the sequence. SlACE expression was studied in the embryonic, larval and pupal stages of S. littoralis and in different tissues of the last larval stage by reverse-transcribed PCR. This revealed that the gene is expressed throughout the life cycle and especially in brain, gut and fat body tissue of the last stage. These results are in agreement with a role of ACE in the metabolism of neuropeptides and gut hormones. In addition, ACE activity has been studied in more detail during development, making use of a fluorescent assay. High ACE peptidase activity coincides with every transition state, from embryo to larva, from larva to larva and from larva to pupa. A peak value in activity occurs during the early pupal stage. These results indicate the importance of SlACE during metamorphosis and reveal the high correlation of ACE activity with the insect's development, which is regulated by growth and developmental hormones.

Time-measurement-regulating peptide PIN may alter a timer conformation of Time Interval Measuring Enzyme (TIME).

PubMed

Ti, Xiaonan; Tani, Naoki; Isobe, Minoru; Kai, Hidenori

2006-05-01

The TIME (Time Interval Measuring Enzyme) ATPase measures time intervals in accordance with diapause development, which indispensably requires cold for resumption of embryonic development in the silkworm (Bombyx mori). The PIN (Peptidyl Inhibitory Needle) peptide regulates the time measurement function of TIME. In the present study we investigated the interaction between TIME and PIN in order to address the mechanism of diapause development. When TIME was isolated from eggs later than 12 days after oviposition, transient bursts of ATPase activity occurred 18h after isolation of TIME, and the younger the eggs and pupal ovaries from which TIME was isolated, the earlier the bursts of ATPase activity appeared. However, no interval-timer activation of ATPase occurred in ovaries earlier than 6 days after pupation. Similar patterns of ATPase activity occurred in test tubes after mixing TIME with PIN. The shorter the time PIN was mixed with TIME, the earlier the ATPase activity appeared. The timer may be built into the protein conformation of TIME, and PIN (which is present in ovaries beginning 6 days after pupation) appears able to alter this timer conformation through pupal stages to laid eggs. We discuss the possible mechanism of diapause development in relation to the timer mechanism of TIME.

The predatory mite Neoseiulus womersleyi (Acari: Phytoseiidae) follows extracts of trails left by the two-spotted spider mite Tetranychus urticae (Acari: Tetranychidae).

PubMed

Shinmen, Tsubasa; Yano, Shuichi; Osakabe, Mh

2010-10-01

As it walks, the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) spins a trail of silk threads, that is followed by the predatory mite, Neoseiulus womersleyi Schicha (Acari: Phytoseiidae). Starved adult female N. womersleyi followed T. urticae trails laid down by five T. urticae females but did not follow a trail of one T. urticae female, suggesting that the amount of spun threads and their chemical components should correlate positively with the number of T. urticae individuals. To examine whether chemical components of T. urticae trails are responsible for the predatory mite's trail following, we collected separate T. urticae threads from the exuviae and eggs, and then washed the threads with methanol to separate chemical components from physical attributes of the threads. Female N. womersleyi did not follow T. urticae trails that had been washed with methanol but contained physical residues, but they did follow the direction to which the methanol extracts of the T. urticae trails was applied. These results suggest that the predatory mite follows chemical, not physical, attributes of T. urticae trails.

Feeding ecology of arctic-nesting sandpipers during spring migration through the prairie pothole region

USGS Publications Warehouse

Eldridge, J.L.; Krapu, G.L.; Johnson, D.H.

2009-01-01

We evaluated food habits of 4 species of spring-migrant calidrid sandpipers in the Prairie Pothole Region (PPR) of North Dakota. Sandpipers foraged in several wetland classes and fed primarily on aquatic dipterans, mostly larvae, and the midge family Chironomidae was the primary food eaten. Larger sandpiper species foraged in deeper water and took larger larvae than did smaller sandpipers. The diverse wetland habitats that migrant shorebirds use in the PPR suggest a landscape-level approach be applied to wetland conservation efforts. We recommend that managers use livestock grazing and other tools, where applicable, to keep shallow, freshwater wetlands from becoming choked with emergent vegetation limiting chironomid production and preventing shorebird use.

An agent-based model of tsetse fly response to seasonal climatic drivers: Assessing the impact on sleeping sickness transmission rates.

PubMed

Alderton, Simon; Macleod, Ewan T; Anderson, Neil E; Palmer, Gwen; Machila, Noreen; Simuunza, Martin; Welburn, Susan C; Atkinson, Peter M

2018-02-01

This paper presents the development of an agent-based model (ABM) to incorporate climatic drivers which affect tsetse fly (G. m. morsitans) population dynamics, and ultimately disease transmission. The model was used to gain a greater understanding of how tsetse populations fluctuate seasonally, and investigate any response observed in Trypanosoma brucei rhodesiense human African trypanosomiasis (rHAT) disease transmission, with a view to gaining a greater understanding of disease dynamics. Such an understanding is essential for the development of appropriate, well-targeted mitigation strategies in the future. The ABM was developed to model rHAT incidence at a fine spatial scale along a 75 km transect in the Luangwa Valley, Zambia. The model incorporates climatic factors that affect pupal mortality, pupal development, birth rate, and death rate. In combination with fine scale demographic data such as ethnicity, age and gender for the human population in the region, as well as an animal census and a sample of daily routines, we create a detailed, plausible simulation model to explore tsetse population and disease transmission dynamics. The seasonally-driven model suggests that the number of infections reported annually in the simulation is likely to be a reasonable representation of reality, taking into account the high levels of under-detection observed. Similar infection rates were observed in human (0.355 per 1000 person-years (SE = 0.013)), and cattle (0.281 per 1000 cattle-years (SE = 0.025)) populations, likely due to the sparsity of cattle close to the tsetse interface. The model suggests that immigrant tribes and school children are at greatest risk of infection, a result that derives from the bottom-up nature of the ABM and conditioning on multiple constraints. This result could not be inferred using alternative population-level modelling approaches. In producing a model which models the tsetse population at a very fine resolution, we were able to analyse and evaluate specific elements of the output, such as pupal development and the progression of the teneral population, allowing the development of our understanding of the tsetse population as a whole. This is an important step in the production of a more accurate transmission model for rHAT which can, in turn, help us to gain a greater understanding of the transmission system as a whole.

Genes involved in thoracic exoskeleton formation during the pupal-to-adult molt in a social insect model, Apis mellifera.

PubMed

Soares, Michelle Prioli Miranda; Barchuk, Angel Roberto; Simões, Ana Carolina Quirino; Dos Santos Cristino, Alexandre; de Paula Freitas, Flávia Cristina; Canhos, Luísa Lange; Bitondi, Márcia Maria Gentile

2013-08-28

The insect exoskeleton provides shape, waterproofing, and locomotion via attached somatic muscles. The exoskeleton is renewed during molting, a process regulated by ecdysteroid hormones. The holometabolous pupa transforms into an adult during the imaginal molt, when the epidermis synthe3sizes the definitive exoskeleton that then differentiates progressively. An important issue in insect development concerns how the exoskeletal regions are constructed to provide their morphological, physiological and mechanical functions. We used whole-genome oligonucleotide microarrays to screen for genes involved in exoskeletal formation in the honeybee thoracic dorsum. Our analysis included three sampling times during the pupal-to-adult molt, i.e., before, during and after the ecdysteroid-induced apolysis that triggers synthesis of the adult exoskeleton. Gene ontology annotation based on orthologous relationships with Drosophila melanogaster genes placed the honeybee differentially expressed genes (DEGs) into distinct categories of Biological Process and Molecular Function, depending on developmental time, revealing the functional elements required for adult exoskeleton formation. Of the 1,253 unique DEGs, 547 were upregulated in the thoracic dorsum after apolysis, suggesting induction by the ecdysteroid pulse. The upregulated gene set included 20 of the 47 cuticular protein (CP) genes that were previously identified in the honeybee genome, and three novel putative CP genes that do not belong to a known CP family. In situ hybridization showed that two of the novel genes were abundantly expressed in the epidermis during adult exoskeleton formation, strongly implicating them as genuine CP genes. Conserved sequence motifs identified the CP genes as members of the CPR, Tweedle, Apidermin, CPF, CPLCP1 and Analogous-to-Peritrophins families. Furthermore, 28 of the 36 muscle-related DEGs were upregulated during the de novo formation of striated fibers attached to the exoskeleton. A search for cis-regulatory motifs in the 5'-untranslated region of the DEGs revealed potential binding sites for known transcription factors. Construction of a regulatory network showed that various upregulated CP- and muscle-related genes (15 and 21 genes, respectively) share common elements, suggesting co-regulation during thoracic exoskeleton formation. These findings help reveal molecular aspects of rigid thoracic exoskeleton formation during the ecdysteroid-coordinated pupal-to-adult molt in the honeybee.

The Simulium nigritarse subgroup (Diptera: Simuliidae) in Uganda: New species and country records.

PubMed

Krüger, Andreas

2016-06-07

Amongst blackfly samples from western Uganda three different morphospecies of the Simulium (Nevermannia) nigritarse Coquillett subgroup were identified. Of these, S. perforatum Fain & Dujardin showed the widest distribution and is reported from Uganda for the first time. In addition, two new species are described: S. bwambanum sp. nov. and S. itwariense sp. nov. Diagnostic characters are the different structures of the pupal cocoon, the configurations of the gill filaments and adult colour features.

Evaluation of Aedes Aegypti Presence and Abundance in Septic Tanks and Their Impacts on Dengue Transmission

DTIC Science & Technology

2009-03-10

problem was further compounded by the public’s incomplete understanding regarding the importance of Ae. aegypti. Many of the individuals surveyed ... survey of the community may identify the significant sources of pupae and help direct subsequent reduction efforts.59 A final point to consider...mosquitoes (all species), but as previously mentioned, they have not been shown to reduce the burden of disease. In contrast, pupal survey results and source

Genetic Interaction of Centrosomin and Bazooka in Apical Domain Regulation in Drosophila Photoreceptor

PubMed Central

Chen, Geng; Rogers, Alicia K.; League, Garrett P.; Nam, Sang-Chul

2011-01-01

Background Cell polarity genes including Crumbs (Crb) and Par complexes are essential for controlling photoreceptor morphogenesis. Among the Crb and Par complexes, Bazooka (Baz, Par-3 homolog) acts as a nodal component for other cell polarity proteins. Therefore, finding other genes interacting with Baz will help us to understand the cell polarity genes' role in photoreceptor morphogenesis. Methodology/Principal Findings Here, we have found a genetic interaction between baz and centrosomin (cnn). Cnn is a core protein for centrosome which is a major microtubule-organizing center. We analyzed the effect of the cnn mutation on developing eyes to determine its role in photoreceptor morphogenesis. We found that Cnn is dispensable for retinal differentiation in eye imaginal discs during the larval stage. However, photoreceptors deficient in Cnn display dramatic morphogenesis defects including the mislocalization of Crumbs (Crb) and Bazooka (Baz) during mid-stage pupal eye development, suggesting that Cnn is specifically required for photoreceptor morphogenesis during pupal eye development. This role of Cnn in apical domain modulation was further supported by Cnn's gain-of-function phenotype. Cnn overexpression in photoreceptors caused the expansion of the apical Crb membrane domain, Baz and adherens junctions (AJs). Conclusions/Significance These results strongly suggest that the interaction of Baz and Cnn is essential for apical domain and AJ modulation during photoreceptor morphogenesis, but not for the initial photoreceptor differentiation in the Drosophila photoreceptor. PMID:21253601

Five new species of the Simulium decuplum subgroup of the Simulium (Gomphostilbia) batoense species-group (Diptera: Simuliidae) from Thailand and their phylogenetic relationships.

PubMed

Takaoka, Hiroyuki; Srisuka, Wichai; Van Lun Low; Saeung, Atiporn

2018-06-01

Five new species of black flies, Simulium (Gomphostilbia) chiangraiense, S. (G.) huaikaeoense, S. (G.) khaokhoense, S. (G.) maeklangense, and S. (G.) pamiangense, are described based on adults, pupae and mature larvae from Thailand. These five species are similar to one another and are placed in the S. decuplum subgroup of the S. batoense species-group by having the male fore coxae darkened, ventral plate flat and transverse; pupal gill with 10 short filaments; and larval postgenal cleft deep approaching or reaching the posterior margin of the hypostoma. Simulium (G.) chiangraiense sp. nov. and S. (G.) pamiangense sp. nov. differ from the three other new species by the much longer pupal gill filaments and darkened dorsal surface of abdominal segments 1 and 2. Taxonomic notes are provided to distinguish these five new species from five other related species. The phylogenetic positions of these new species in the S. decuplum subgroup are presented based on the mitochondrial COI gene. Simulium (G.) pamiangense sp. nov. and S. (G.) huaikaeoense sp. nov. are highly similar to each other genetically, showing a sister relationship, though they are clearly different morphologically. On the contrary, S. (G.) khaokhoense sp. nov. is distantly positioned from S. (G.) huaikaeoense nov., though it is almost indistinguishable morphologically from the latter. Copyright © 2018 Elsevier B.V. All rights reserved.

Adenanthera pavonina trypsin inhibitor retard growth of Anagasta kuehniella (Lepidoptera: Pyralidae).

PubMed

Macedo, Maria Lígia Rodrigues; Durigan, Roberta Aparecida; da Silva, Desiree Soares; Marangoni, Sérgio; Freire, Maria das Graças Machado; Parra, José Roberto Postali

2010-04-01

Anagasta kuehniella is a polyphagous pest that feeds on a wide variety of stored products. The possible roles suggested for seed proteinase inhibitors include the function as a part of the plant defensive system against pest via inhibition of their proteolytic enzymes. In this study, a trypsin inhibitor (ApTI) was purified from Adenanthera pavonina seed and was tested for insect growth regulatory effect. The chronic ingestion of ApTI did result in a significant reduction in larval survival and weight. Larval and pupal developmental time of larvae fed on ApTI diet at 1% was significantly longer; the larval period was extended by 5 days and pupal period was 10 days longer, therefore delaying by up to 20 days and resulting in a prolonged period of development from larva to adult. As a result, the ApTI diet emergence rate was only 28% while the emergence rate of control larvae was 80%. The percentage of surviving adults (%S) decreased to 62%. The fourth instar larvae reared on a diet containing 1% ApTI showed a decrease in tryptic activity of gut and that no novel proteolytic form resistant to ApTI was induced. In addition, the tryptic activity in ApTI -fed larvae was sensitive to ApTI. These results suggest that ApTI have a potential antimetabolic effect when ingested by A. kuehniella. (c) 2010 Wiley Periodicals, Inc.

The parasitoids of the asparagus miner (Diptera: Agromyzidae): field parasitism and the influence of food resources on life history.

PubMed

Morrison, William R; Gibson, Gary A P; Szendrei, Zsofia

2014-12-01

The goals of this study were to identify pupal parasitoids of the asparagus miner, Ophiomyia simplex Loew (Diptera: Agromyzidae), and examine the effect of different diets and floral resources on the lifespan of adult asparagus miners and their parasitoids. We also measured the effect of parasitism on stem damage caused by the asparagus miner. The identity and abundance of the parasitoids of the asparagus miner were determined in asparagus fields in Michigan from weekly asparagus miner pupal collections during the 2010-2013 seasons. Twelve species of hymenopterous parasitoids were reared from asparagus miner pupae, including Chorebus rondanii (Giard) (Ichneumonoidea: Braconidae), 10 species in three families of Chalcidoidea, and one species of Bethylidae (Chrysidoidea), that represent new host records for the asparagus miner. C. rondanii and Thinodytes cephalon (Walker) (Pteromalidae) were the most common parasitoids. The effects of different diets and flowers on the lifespan of the pest and parasitoid adults were also evaluated. Buckwheat resulted in the shortest life span for the asparagus miner, whereas Riddell's goldenrod significantly increased its lifespan relative to the control. Parasitoid lifespan was doubled when individuals were fed sugar-rich diets. In the field, parasitoids preferred stems that contained more pupae and damage. The two most commonly reared parasitoids should be considered as targets for future conservation biological control efforts of the asparagus miner.

Real-time analysis of Drosophila post-embryonic haemocyte behaviour.

PubMed

Sampson, Christopher J; Williams, Michael J

2012-01-01

The larval stage of the model organism Drosophila is frequently used to study host-pathogen interactions. During embryogenesis the cellular arm of the immune response, consisting of macrophage-like cells known as plasmatocytes, is extremely motile and functions to phagocytise pathogens and apoptotic bodies, as well as produce extracellular matrix. The cellular branch of the larval (post-embryonic) innate immune system consists of three cell types--plasmatocytes, crystal cells and lamellocytes--which are involved in the phagocytosis, encapsulation and melanisation of invading pathogens. Post-embryonic haemocyte motility is poorly understood thus further characterisation is required, for the purpose of standardisation. In order to examine post-embryonic haemocyte cytoskeletal dynamics or migration, the most commonly used system is in vitro cell lines. The current study employs an ex vivo system (an adaptation of in vitro cell incubation using primary cells), in which primary larval or pre-pupal haemocytes are isolated for short term analysis, in order to discover various aspects of their behaviour during events requiring cytoskeleton dynamics. The ex vivo method allows for real-time analysis and manipulation of primary post-embryonic haemocytes. This technique was used to characterise, and potentially standardised, larval and pre-pupal haemocyte cytoskeleton dynamics, assayed on different extracellular matrices. Using this method it was determined that, while larval haemocytes are unable to migrate, haemocytes recovered from pre-pupae are capable of migration.

Effects of juvenile hormone (JH) analog insecticides on larval development and JH esterase activity in two spodopterans.

PubMed

El-Sheikh, El-Sayed A; Kamita, Shizuo G; Hammock, Bruce D

2016-03-01

Juvenile hormone analog (JHA) insecticides are biological and structural mimics of JH, a key insect developmental hormone. Toxic and anti-developmental effects of the JHA insecticides methoprene, fenoxycarb, and pyriproxyfen were investigated on the larval and pupal stages of Spodoptera littoralis and Spodoptera frugiperda. Bioassays showed that fenoxycarb has the highest toxicity and fastest speed of kill in 2nd instar S. littoralis. All three JHAs affected the development of 6th instar (i.e., final instar) and pupal S. frugiperda. JH esterase (JHE) is a critical enzyme that helps to regulate JH levels during insect development. JHE activity in the last instar S. littoralis and S. frugiperda was 11 and 23 nmol min(-1) ml(-1) hemolymph, respectively. Methoprene and pyriproxyfen showed poor inhibition of JHE activity from these insects, whereas fenoxycarb showed stronger inhibition. The inhibitory activity of fenoxycarb, however, was more than 1000-fold lower than that of OTFP, a highly potent inhibitor of JHEs. Surprisingly, topical application of methoprene, fenoxycarb or pyriproxyfen on 6th instars of S. littoralis and S. frugiperda prevented the dramatic reduction in JHE activity that was found in control insects. Our findings suggest that JHAs may function as JH agonists that play a disruptive role or a hormonal replacement role in S. littoralis and S. frugiperda. Copyright © 2015 Elsevier B.V. All rights reserved.

Summer diapause induced by high temperatures in the oriental tobacco budworm: ecological adaptation to hot summers

PubMed Central

Liu, Zhudong; Xin, Yucui; Zhang, Yanan; Fan, Jianting; Sun, Jianghua

2016-01-01

Summer diapause in Helicoverpa assulta (Hübner), which prolongs the pupal stage, particularly in males, is induced by high temperatures. In the laboratory, 3rd-, 4th-, 6th-instar and prepupal larvae were exposed to high temperatures – 33 and 35 °C with a photoperiod of LD16:8 – until pupation to induce summer diapause. The results showed that the incidence of summer diapause was influenced by temperature, stage exposed, and sex. The higher the temperature, the more often summer diapause was attained. Sixth-instar and prepupal larvae were the sensitive stages for summer diapause induction. H. assulta summer-diapausing pupae needed diapause development to resume development when temperatures became favorable. Furthermore, both body mass and energy storage capacity (lipid and glycogen) were significantly affected by diapause rather than sex, and were significantly higher in summer-diapausing pupae than in non-diapausing pupae. In addition, the body mass loss and respiration rate showed that the rate of metabolism in the summer-diapausing pupae was consistently lower than in non-diapausing pupae, which were significantly affected by diapause and pupal age. We conclude that summer diapause in H. assulta is a true diapause, and H. assulta has evolved mechanisms to accumulate energy storage and to lower its metabolism to adapt to hot summers. PMID:27271223

Development of quality control procedures for mass produced and released Bactrocera Philippinensis (Diptera: Tephritidae) for sterile insect technique programs

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

Resilva, S.; Obra, G.; Zamora, N.

Quality control procedures for Bactrocera philippinensis Drew and Hancock 1994 (Diptera: Tephritidae) used in sterile insect technique (SIT) programs were established in the mass rearing facility at the Philippine Nuclear Research Institute. Basic studies on pupal irradiation, holding/packaging systems, shipping procedures, longevity, sterility studies, and pupal eye color determination in relation to physiological development at different temperature regimes were investigated. These studies will provide baseline data for the development of quality control protocols for an expansion of B. philippinensis field programs with an SIT component in the future. (author) [Spanish] Los procedimientos de control de calidad para Bactrocera philippinensis Drewmore » y Hancock 1994 (Diptera: Tephritidae) usados en programas de la tecnica de insecto esteril (TIE) fueron establecidos en la facilidad de cria en masa del Instituto Filipino de Investigacion Nuclear. Estudios basicos sobre la irradiacion de las pupas, sistemas de almacenaje/empaque, procedimientos del envio, longevidad, estudios de esterilidad y la determinacion del color de ojo de la pupa en relacion con el desarrollo fisiologico en regimenes diferentes de temperatura fueron investigados. Estos estudios proveeran una linea de informacion basica para el desarrollo de protocolos de control de calidad para una expansion de los programas de campo para B. philippinensis con un componente de TIS en el futuro. (author)« less

Further Screening of Entomopathogenic Fungi and Nematodes as Control Agents for Drosophila suzukii

PubMed Central

Cuthbertson, Andrew G. S.; Audsley, Neil

2016-01-01

Drosophila suzukii populations remain low in the UK. To date, there have been no reports of widespread damage. Previous research demonstrated that various species of entomopathogenic fungi and nematodes could potentially suppress D. suzukii population development under laboratory trials. However, none of the given species was concluded to be specifically efficient in suppressing D. suzukii. Therefore, there is a need to screen further species to determine their efficacy. The following entomopathogenic agents were evaluated for their potential to act as control agents for D. suzukii: Metarhizium anisopliae; Isaria fumosorosea; a non-commercial coded fungal product (Coded B); Steinernema feltiae, S. carpocapsae, S. kraussei and Heterorhabditis bacteriophora. The fungi were screened for efficacy against the fly on fruit while the nematodes were evaluated for the potential to be applied as soil drenches targeting larvae and pupal life-stages. All three fungi species screened reduced D. suzukii populations developing from infested berries. Isaria fumosorosea significantly (p < 0.001) reduced population development of D. suzukii from infested berries. All nematodes significantly reduced adult emergence from pupal cases compared to the water control. Larvae proved more susceptible to nematode infection. Heterorhabditis bacteriophora proved the best from the four nematodes investigated; readily emerging from punctured larvae and causing 95% mortality. The potential of the entomopathogens to suppress D. suzukii populations is discussed. PMID:27294962

Acute, sublethal, and combination effects of azadirachtin and Bacillus thuringiensis on the cotton bollworm, Helicoverpa armigera.

PubMed

Abedi, Zahra; Saber, Moosa; Vojoudi, Samad; Mahdavi, Vahid; Parsaeyan, Ehsan

2014-02-26

The cotton bollworm, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a polyphagous and cosmopolitan insect pest that causes damage to various plants. In this study, the lethal and sublethal effects of azadirachtin and Bacillus thuringiensis Berliner sub sp . kurstaki (Bacillales: Bacillaceae) were evaluated on third instar H. armigera under laboratory conditions. The LC50 values of azadirachtin and Bt were 12.95 and 96.8 µg a.i./mL, respectively. A total mortality of 56.7% was caused on third instar larvae when LC20 values of the insecticides were applied in combination with each other. The LT50 values of azadirachtin and Bt were 4.8 and 3.6 days, respectively. The results of the sublethal study showed that the application of LC30 value of azadirachtin and Bt reduced the larval and pupal weight and increased larval and pupal duration of H. armigera. The longevity and fecundity of female adults were affected significantly by the insecticides. Female fecundity was reduced by the treatments, respectively. The lowest adult emergence ratio and pupation ratio were observed in the azadirachtin treatment. The results indicated that both insecticides have high potential for controlling of the pest. 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.

Unique Temporal Expression of Triplicated Long-Wavelength Opsins in Developing Butterfly Eyes

PubMed Central

Arikawa, Kentaro; Iwanaga, Tomoyuki; Wakakuwa, Motohiro; Kinoshita, Michiyo

2017-01-01

Following gene duplication events, the expression patterns of the resulting gene copies can often diverge both spatially and temporally. Here we report on gene duplicates that are expressed in distinct but overlapping patterns, and which exhibit temporally divergent expression. Butterflies have sophisticated color vision and spectrally complex eyes, typically with three types of heterogeneous ommatidia. The eyes of the butterfly Papilio xuthus express two green- and one red-absorbing visual pigment, which came about via gene duplication events, in addition to one ultraviolet (UV)- and one blue-absorbing visual pigment. We localized mRNAs encoding opsins of these visual pigments in developing eye disks throughout the pupal stage. The mRNAs of the UV and blue opsin are expressed early in pupal development (pd), specifying the type of the ommatidium in which they appear. Red sensitive photoreceptors first express a green opsin mRNA, which is replaced later by the red opsin mRNA. Broadband photoreceptors (that coexpress the green and red opsins) first express the green opsin mRNA, later change to red opsin mRNA and finally re-express the green opsin mRNA in addition to the red mRNA. Such a unique temporal and spatial expression pattern of opsin mRNAs may reflect the evolution of visual pigments and provide clues toward understanding how the spectrally complex eyes of butterflies evolved. PMID:29238294

Exploitation of the Medfly Gut Microbiota for the Enhancement of Sterile Insect Technique: Use of Enterobacter sp. in Larval Diet-Based Probiotic Applications

PubMed Central

Papadopoulos, Nikos T.; Abd-Alla, Adly M. M.; Cáceres, Carlos; Bourtzis, Kostas

2015-01-01

The Mediterranean fruit fly (medfly), Ceratitis capitata, is a pest of worldwide substantial economic importance, as well as a Tephritidae model for sterile insect technique (SIT) applications. The latter is partially due to the development and utilization of genetic sexing strains (GSS) for this species, such as the Vienna 8 strain, which is currently used in mass rearing facilities worldwide. Improving the performance of such a strain both in mass rearing facilities and in the field could significantly enhance the efficacy of SIT and reduce operational costs. Recent studies have suggested that the manipulation of gut symbionts can have a significant positive effect on the overall fitness of insect strains. We used culture-based approaches to isolate and characterize gut-associated bacterial species of the Vienna 8 strain under mass rearing conditions. We also exploited one of the isolated bacterial species, Enterobacter sp., as dietary supplement (probiotic) to the larval diet, and we assessed its effects on fitness parameters under the standard operating procedures used in SIT operational programs. Probiotic application of Enterobacter sp. resulted in improvement of both pupal and adult productivity, as well as reduced rearing duration, particularly for males, without affecting pupal weight, sex ratio, male mating competitiveness, flight ability and longevity under starvation. PMID:26325068

20-Hydroxyecdysone stimulates nuclear accumulation of BmNep1, a nuclear ribosome biogenesis-related protein in the silkworm, Bombyx mori.

PubMed

Ji, M-M; Liu, A-Q; Sima, Y-H; Xu, S-Q

2016-10-01

The pathway of communication between endocrine hormones and ribosome biogenesis critical for physiological adaptation is largely unknown. Nucleolar essential protein 1 (Nep1) is an essential gene for ribosome biogenesis and is functionally conserved in many in vertebrate and invertebrate species. In this study, we cloned Bombyx mori Nep1 (BmNep1) due to its high expression in silk glands of silkworms on day 3 of the fifth instar. We found that BmNep1 mRNA and protein levels were upregulated in silk glands during fourth-instar ecdysis and larval-pupal metamorphosis. By immunoprecipitation with the anti-BmNep1 antibody and liquid chromatography-tandem mass spectrometry analyses, it was shown that BmNep1 probably interacts with proteins related to ribosome structure formation. Immunohistochemistry, biochemical fractionation and immunocytochemistry revealed that BmNep1 is localized to the nuclei in Bombyx cells. Using BmN cells originally derived from ovaries, we demonstrated that 20-hydroxyecdysone (20E) induced BmNep1 expression and stimulated nuclear accumulation of BmNep1. Under physiological conditions, BmNep1 was also upregulated in ovaries during larval-pupal metamorphosis. Overall, our results indicate that the endocrine hormone 20E facilitates nuclear accumulation of BmNep1, which is involved in nuclear ribosome biogenesis in Bombyx. © 2016 The Royal Entomological Society.

Effects of tea saponin on growth and development, nutritional indicators, and hormone titers in diamondback moths feeding on different host plant species.

PubMed

Cai, Hongjiao; Bai, Yan; Wei, Hui; Lin, Shuo; Chen, Yixin; Tian, Houjun; Gu, Xiaojun; Murugan, Kadarkarai

2016-07-01

The diamondback moth (DBM) is an important worldwide pest. This insect has been studied for several decades; however, its control remains problematic. Numerous chemical insecticides have become ineffective and chemical residues constitute an important problem. In the present study, we determined the mortality of 3rd instar DBM larvae feeding on three different host plant species and exposed to various concentrations of tea saponin (TS). In addition, we evaluated growth and development parameters, nutritional indicators, and juvenile hormone (JH) and molting hormone (MH) titers in 2nd instar larvae exposed to LC20 and LC50 doses of TS. We found that treatment of DBM larvae with LC20 and LC50 doses of TS led to lower growth rates, decreased feed consumption, reduced frass production, lower pupal weights, reduced percentage pupation, slower adult emergence percentages, and diminished fecundity, but prolonged durations of the larval and pupal periods. The efficiency of conversion of ingested and digested food increased, but the approximate digestibility did not differ significantly between treatments and controls. JH and MH titers were higher after TS treatment; these increases varied according to the host species and TS concentration. Our results indicate that TS represents a potential new alternative insecticide based on its natural origin, low cost, and minimum environmental impact. Copyright © 2016 Elsevier B.V. All rights reserved.

Induction of resistance of corn plants to Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae) by application of silicon and gibberellic acid.

PubMed

Alvarenga, R; Moraes, J C; Auad, A M; Coelho, M; Nascimento, A M

2017-08-01

The aim of this study was to evaluate the effects of silicon application and administration of the phytohormone gibberellic acid on resistance of the corn plants to the fall armyworm (FAW), Spodoptera frugiperda, and their vegetative characteristics. We evaluated larval and pupal duration, survival and biomass, and adult longevity, malformation and fecundity of S. frugiperda after feeding on plant matter treated with silicon and/or gibberellic acid. The feeding preference of FAW first-instar larvae, the total leaf area consumed by the insects, and the vegetative parameters of corn plants were also evaluated. No significant differences were observed in the measured parameters of larval and pupal stages of S. frugiperda in response to silicon or gibberellic acid. In adult stage insects, the number of eggs per female was significantly reduced in insects derived from larvae fed plants treated with silicon or gibberellic acid. In a non-preference test, 48 h after release, caterpillars preferred control untreated plants and consumed less matter from plants that had received hormonal treatment (gibberellic acid). Gibberellic acid also altered the vegetative characteristics of plants, by increasing their height, shoot fresh and dry mass, and silicon content. We conclude that gibberellic acid can alter the vegetative characteristics and silicon uptake of corn plants, leading to a reduction in their consumption by S. frugiperda larvae and a decrease in female insect oviposition.

Gas-exchange patterns of Mediterranean fruit fly Pupae (Diptera: Tephritidae): A tool to forecast developmental stage

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

Nestel, D.; Nemny-Lavy, E.; Alchanatis, V.

The pattern of gas-exchange (CO{sub 2} emission) was investigated for developing Mediterranean fruit fly (medfly) Ceratitis capitata (Wiedemann) pupae incubated at different temperatures. This study was undertaken to explore the usefulness of gas-exchange systems in the determination of physiological age in developing pupae that are mass produced for sterile insect technique projects. The rate of CO{sub 2} emission was measured in a closed flow-through system connected to commercial infrared gas analysis equipment. Metabolic activity (rate of CO{sub 2} emission) was related to pupal eye-color, which is the current technique used to determine physiological age. Eye-color was characterized digitally with 3more » variables (Hue, Saturation and Intensity), and color separated by discriminant analysis. The rate of CO{sub 2} emission throughout pupal development followed a U-shape, with high levels of emission during pupariation, pupal transformation and final pharate adult stages. Temperature affected the development time of pupae, but not the basic CO{sub 2} emission patterns during development. In all temperatures, rates of CO{sub 2} emission 1 and 2 d before adult emergence were very similar. After mid larval-adult transition (e.g., phanerocephalic pupa), digital eye-color was significantly correlated with CO{sub 2} emission. Results support the suggestion that gas-exchange should be explored further as a system to determine pupal physiological age in mass production of fruit flies. (author) [Spanish] En el presente estudio se investigaron los patrones de intercambio gaseoso (emision de CO{sub 2}) en pupas de la mosca de las frutas del Mediterraneo (Ceratitis capitata Wiedemann) incubadas a diferentes temperaturas. El estudio fue realizado con la finalidad de explorar la utilizacion de sistemas de intercambio gaseoso en la determinacion de la edad fisiologica de pupas durante su produccion masiva en proyectos de mosca esteril. La proporcion de emision de CO{sub 2} fue medido en un sistema cerrado de 'flujo a traves del sistema' conectado a un detector infrarrojo de gases. La actividad metabolica de la pupa (emision de CO{sub 2}) fue contrastado al color del ojo de la pupa en desarrollo, que constituye la actual tecnica de determinacion de la edad fisiologica. El color de ojos en pupa fue determinado digitalmente, usando tres variables (Tendencia, Saturacion e Intensidad). Los colores fueron separados utilizando el analisis discriminatorio. Los patrones de emision de CO{sub 2} durante el desarrollo de la pupa sugieren una tendencia de U: una alta actividad metabolica durante la fase inicial de pupacion y transformacion y durante la fase final del adulto. La temperatura de incubacion afecto el tiempo de desarrollo pero no el patron basico de actividad metabolica. La proporcion de emision de CO{sub 2} uno y dos dias antes de la emergencia del adulto fue muy similar para pupas mantenidas en las diversas temperaturas. El color digital del ojo de la pupa se correlaciono significativamente con los patrones de emision de CO{sub 2} detectados a partir de la fase media de la transformacion de larva a adulto. Los resultados soportan la utilizacion de sistemas de intercambio gaseoso como un sistema auxiliar para la determinacion de la edad fisiologica en cria masiva de moscas de la fruta. (author)« less

Recovery of three arctic stream reaches from experimental nutrient enrichment

USGS Publications Warehouse

Benstead, J.P.; Green, A.C.; Deegan, Linda A.; Peterson, B.J.; Slavik, K.; Bowden, W.B.; Hershey, A.E.

2007-01-01

1. Nutrient enrichment and resulting eutrophication is a widespread anthropogenic influence on freshwater ecosystems, but recovery from nutrient enrichment is poorly understood, especially in stream environments. We examined multi-year patterns in community recovery from experimental low-concentration nutrient enrichment (N + P or P only) in three reaches of two Arctic tundra streams (Kuparuk River and Oksrukuyik Creek) on the North Slope of Alaska (U.S.A.). 2. Rates of recovery varied among community components and depended on duration of enrichment (2-13 consecutive growing seasons). Biomass of epilithic algae returned to reference levels rapidly (within 2 years), regardless of nutrients added or enrichment duration. Aquatic bryophyte cover, which increased greatly in the Kuparuk River only after long-term enrichment (8 years), took 8 years of recovery to approach reference levels, after storms had scoured most remnant moss in the recovering reach. 3. Multi-year persistence of bryophytes in the Kuparuk River appeared to prevent recovery of insect populations that had either been positively (e.g. the mayfly Ephemerella, most chironomid midge taxa) or negatively (e.g. the tube-building chironomid Orthocladius rivulorum) affected by this shift in dominant primary producer. These lags in recovery (of >3 years) were probably driven by the persistent effect of bryophytes on physical benthic habitat. 4. Summer growth rates of Arctic grayling (both adults and young-of-year) in Oksrukuyik Creek (fertilised for 6 years with no bryophyte colonisation), which were consistently increased by nutrient addition, returned to reference rates within 1-2 years. 5. Rates of recovery of these virtually pristine Arctic stream ecosystems from low-level nutrient enrichment appeared to be controlled largely by duration of enrichment, mediated through physical habitat shifts caused by eventual bryophyte colonisation, and subsequent physical disturbance that removed bryophytes. Nutrient enrichment of oligotrophic Arctic stream ecosystems caused by climate change or local anthropogenic activity may have dramatic and persistent consequences if it results in the colonisation of long-lived primary producers that alter physical habitat. ?? 2007 The Authors.

Wind effects on prey availability: How northward migrating waders use brackish and hypersaline lagoons in the sivash, Ukraine

NASA Astrophysics Data System (ADS)

Verkuil, Yvonne; Koolhaas, Anita; Van Der Winden, Jan

Large numbers of waders migrating northward in spring use the Sivash, a large system of shallow, brackish and hypersaline lagoons in the Black Sea and Azov Sea region (Ukraine). The bottoms of these lagoons are often uncovered by the wind. Hence, for waders the time and space available for feeding depend on wind conditions. In hypersaline lagoons the benthic and pelagic fauna was very poor, consisting mainly of chironomid larvae (0.19 g AFDM·m -2) and brine shrimps Artemia salina, respectively. Brine shrimp abundance was correlated with salinity, wind force, wind direction and water depth. Dunlin Calidris alpina and curlew sandpiper Calidris ferruginea were the only species feeding on brine shrimp. As brine shrimp densities are higher in deeper water, smaller waders such as broad-billed sandpipers Limicola falcinellus are too short-legged to reach exploitable densities of brine shrimp. In brackish lagoons the benthic and pelagic fauna was rich, consisting of polychaetes, bivalves, gastropods, chironomid larvae, isopods and amphipods (8.9 to 30.5 g AFDM·m -2), but there were no brine shrimps. Prey biomass increased with the distance from the coast, being highest on the site that was most frequently inundated. Dunlin, broad-billed sandpiper and grey plover Pluvialis squatarola were the most abundant birds in the brackish lagoon. Due to the effects of wind-tides only a small area was usually available as a feeding site. Gammarus insensibilis was the alternative prey resource in the water layer, and their density varied with wind direction in the same way as brine shrimp. Curlew sandpipers and dunlins in the hypersaline lagoons and broad-billed sandpipers in the brackish lagoons often changed feeding sites, probably following the variation in prey availability. Only because of the large size and variety of lagoons are waders in the Sivash always able to find good feeding sites.

Laboratory and field investigations of pestiferous Chironomidae (Diptera) in some man-made wetlands in central Florida, USA.

PubMed

Ali, Arshad; Leckel, Robert J; Jahan, Nusrad; Al-Shami, Salman A; Rawi, Che Salmah Md

2009-03-01

A 1-year larval and adult population survey of pestiferous chironomids was conducted in 4 man-made wetlands in a resort area of central Florida, USA. Benthic samples were randomly collected from each wetland at least once every month. Geocoordinates, water depth, and physical composition of substrates at each larval sample location were noted. Adult midge populations were sampled weekly around the wetlands by employing 10 New Jersey light traps permanently placed in the area. Chironominae and Tanypodinae midges occurred in the larval and adult samples; a few Orthocladiinae were also taken. Among Chironominae, Chironomini (mostly Polypedilum spp., Cryptochironomus spp., Glyptotendipes paripes, and Goeldichironomus carus) and Tanytarsini (mostly Tanytarsus spp.), and some other Chironomidae were recorded. Tanypodinae were quantitatively not important. Monthly mean number of total adults per trap-night ranged from 23 in February to 211 in October. Annual mean larval density and range of total chironomids in the study wetlands amounted to 1,128/m2, range: 0-12,332/m2. The total larvae were most abundant in May. Tanytarsus spp. and Polypedilum spp. were numerically the most predominant spatially as well as temporally. Mean water depth at the sampled locations was 1.83 m (range: <1-8.75 m); 47% of the total collected larvae occurred at <1-m water depth and 53% at >1-m-deep water. Of all sampled locations, substrates such as sand, mixed substrates, and muck were respectively encountered at 656, 371, and 299 locations. The predominance of sand and mixed substrates was conducive to supporting the numerically dominant Tanytarsus spp. and Polypedilum spp. In laboratory bioassays, Tanytarsus spp., Polypedilum spp., Glyptotendipes paripes, and Goeldichironomus carus were highly susceptible to temephos, as well as to s-methoprene. Bacillus thuringiensis serovar. israelensis was most effective against Tanytarsus spp. and least against Goeldichironomus carus.

Reconstruction of Holocene environmental changes in Southern Kurils (North-Western Pacific) based on palaeolake sediment proxies from Shikotan Island

NASA Astrophysics Data System (ADS)

Nazarova, Larisa; Grebennikova, Tatiana A.; Razjigaeva, Nadezhda G.; Ganzey, Larisa A.; Belyanina, Nina I.; Arslanov, Khikmat A.; Kaistrenko, Victor M.; Gorbunov, Aleksey O.; Kharlamov, Andrey A.; Rudaya, Natalia; Palagushkina, Olga; Biskaborn, Boris K.; Diekmann, Bernhard

2017-12-01

We investigated a well-dated sediment section of a palaeolake situated in the coastal zone of Shikotan Island (Lesser Kurils) for organic sediment-geochemistry and biotic components (diatoms, chironomids, pollen) in order to provide a reconstruction of the palaeoenvironmental changes and palaeo-events (tsunamis, sea-level fluctuations and landslides) in Holocene. During the ca 8000 years of sedimentation the changes in organic sediment-geochemistry and in composition of the diatoms and chironomids as well as the shifts in composition of terrestrial vegetation suggest that the period until ca 5800 cal yr BP was characterized by a warm and humid climate (corresponds to middle Holocene optimum) with climate cooling thereafter. A warm period reconstructed from ca 900 to at least ca 580 cal yr BP corresponds to a transition to a Nara-Heian-Kamakura warm stage and can be correlated to a Medieval Warm Period. After 580 cal yr PB, the lake gradually dried out and climatic signals could not be obtained from the declining lacustrine biological communities, but the increasing role of spruce and disappearance of the oak from the vegetation give evidences of the climate cooling that can be correlated with the LIA. The marine regression stages at the investigated site are identified for ca 6200-5900 (at the end of the middle Holocene transgression), ca 5500-5100 (Middle Jomon regression or Kemigawa regression), and ca 1070-360 cal yr BP (at the end of Heian transgression). The lithological structure of sediments and the diatom compositions give evidences for the multiple tsunami events of different strengths in the Island. Most remarkable of them can be dated at around ca 7000, 6460, 5750, 4800, 950 cal yr BP. The new results help to understand the Holocene environmental history of the Southern Kurils as a part of the Kuril-Kamchatka and Aleutian Marginal Sea-Island Arc Systems in the North-Western Pacific region.

Small ecosystem engineers as important regulators of lake's sediment respiration.

NASA Astrophysics Data System (ADS)

Baranov, Victor; Lewandowski, Joerg; Krause, Stefan; Romeijn, Paul

2016-04-01

Although shallow lakes are covering only about 1.5% of the land surface of the Earth, they are responsible for sequestration of carbon amounts similar or even larger than those sequestered in all marine sediments. One of the most important drivers of the carbon sequestration in lakes is sediment respiration. Especially in shallow lakes, bioturbation, i.e. the biogenic reworking of the sediment matrix and the transport of fluids within the sediment, severely impacts on sediment respiration. Widespread freshwater bioturbators such as chironomid larvae (Diptera, Chironomidae) are building tubes in the sediment and actively pump water through their burrows (ventilation). In the present work we study how different organism densities and temperatures (5-30°C) impact on respiration rates. In a microcosm experiment the bioreactive resazurin/resorufin smart tracer system was applied for quantifying the impacts of different densities of Chironomidae (Diptera) larvae (0, 1000, 2000 larvae/m2) on sediment respiration. Tracer transformation rates (and sediment respiration) were correlated with larval densities with highest transformation rates occurring in microcosms with highest larval densities. Respiration differences between defaunated sediment and sediment with 1000 and 2000 larvae per m2 was insignificant at 5 °C, and was progressively increasing with rising temperatures. At 30 °C respiration rates of sediment with 2000 larvae per m2 was 4.8 times higher than those of defaunated sediment. We interpret this as an effect of temperature on larval metabolic and locomotory activity. Furthermore, bacterial communities are benefiting from the combination of the high water temperatures and bioirrigation as bacterial community are able to maintain high metabolic rates due to oxygen supplied by bioirrigation. In the context of global climate change that means that chironomid ecosystem engineering activity will have a profound and increasing impact on lake sediment respiration and carbon sequestration due to a warming world.

Evidence for Isostatic Emergence and Holocene Environmental Change Recorded in Chironomid Assemblages and Sediment Composition of Coastal Lake T1 in SW Greenland

NASA Astrophysics Data System (ADS)

Berman, K.; Axford, Y.; Lasher, G. E.

2017-12-01

Multi-proxy analysis of a coastal lake in southwest Greenland near Nuuk provides evidence for regional environmental changes, including the timing of isostatic rebound and the temperature history of the area. T1 (informal name) is a small lake 50 km south of Nuuk, at 17.5 m elevation and currently isolated from glacial meltwater drainage. The lake's sediment record begins approximately 9500 cal years BP, when the site was submerged beneath sea level due to glacial isostatic depression following the Last Glacial Maximum. The record captures the transition of the environment from a submerged, glacially-influenced marine site to a non-glacially fed (and initially meromictic) freshwater lake 8600 cal years BP. Magnetic susceptibility, a proxy for sediment minerogenic content, decreased rapidly from 9500 to 8600 years BP, before abruptly stabilizing and remaining relatively low and steady for the rest of the record. The transition to a lacustrine environment was characterized by a rapid and relatively simultaneous increase in primary productivity (inferred from biogenic silica concentrations) and shift towards terrestrial versus marine sources of organic matter (inferred from carbon:nitrogen ratios and nitrogen isotopes) between 8700 and 8400 years BP. Together, these proxies and the presence of marine shells below the transition provide robust evidence for the transition from a marine environment to a freshwater lake in response to regional postglacial isostatic rebound. Within the Holocene, measures of bulk sediment composition (e.g., biogenic silica, loss-on-ignition and magnetic susceptibility) are relatively stable. Chironomid (Insecta: Diptera: Chironomidae) assemblages, which in some environments are quantitative proxies for summer temperature changes, show species-level shifts within the Holocene that will be interpreted in this presentation alongside indicators of landscape change including carbon:nitrogen ratios, bulk sediment spectral reflectance and bulk sediment elemental composition from scanning XRF.

Zebra mussel beds: an effective feeding ground for Ponto-Caspian gobies or suitable shelter for their prey?

PubMed

Kobak, Jarosław; Poznańska, Małgorzata; Jermacz, Łukasz; Kakareko, Tomasz; Prądzynski, Daniel; Łodygowska, Małgorzata; Montowska, Karolina; Bącela-Spychalska, Karolina

2016-01-01

Aggregations of the Ponto-Caspian invasive zebra mussel ( Dreissena polymorpha ) constitute a suitable habitat for macroinvertebrates, considerably increasing their abundance and providing effective antipredator protection. Thus, the overall effect of a mussel bed on particular predator species may vary from positive to negative, depending on both prey density increase and predator ability to prey in a structurally complex habitat. Alien Ponto-Caspian goby fish are likely to be facilitated when introduced into new areas by zebra mussels, provided that they are capable of utilizing mussel beds as habitat and feeding grounds. We ran laboratory experiments to find which prey (chironomid larvae) densities (from ca. 500 to 2,000 individuals m -2 ) in a mussel bed make it a more beneficial feeding ground for the racer goby Babka gymnotrachelus (RG) and western tubenose goby Proterorhinus semilunaris (WTG) compared to sandy and stone substrata (containing the basic prey density of 500 ind. m -2 ). Moreover, we checked how food availability affects habitat selection by fish. Mussel beds became more suitable for fish than alternative mineral substrata when food abundance was at least two times higher (1,000 vs. 500 ind. m -2 ), regardless of fish size and species. WTG was associated with mussel beds regardless of its size and prey density, whereas RG switched to this habitat when it became a better feeding ground than alternative substrata. Larger RG exhibited a stronger affinity for mussels than small individuals. WTG fed more efficiently from a mussel bed at high food abundances than RG. A literature review has shown that increasing chironomid density, which in our study was sufficient to make a mussel habitat an attractive feeding ground for the gobies, is commonly observed in mussel beds in the field. Therefore, we conclude that zebra mussels may positively affect the alien goby species and are likely to facilitate their establishment in novel areas, contributing to an invasional meltdown in the Ponto-Caspian invasive community.

Rock glaciers in crystalline catchments: Hidden permafrost-related threats to alpine headwater lakes.

PubMed

Ilyashuk, Boris P; Ilyashuk, Elena A; Psenner, Roland; Tessadri, Richard; Koinig, Karin A

2018-04-01

A global warming-induced transition from glacial to periglacial processes has been identified in mountainous regions around the world. Degrading permafrost in pristine periglacial environments can produce acid rock drainage (ARD) and cause severe ecological damage in areas underlain by sulfide-bearing bedrock. Limnological and paleolimnological approaches were used to assess and compare ARDs generated by rock glaciers, a typical landform of the mountain permafrost domain, and their effects on alpine headwater lakes with similar morphometric features and underlying bedrock geology, but characterized by different intensities of frost action in their catchments during the year. We argue that ARD and its effects on lakes are more severe in the alpine periglacial belt with mean annual air temperatures (MAAT) between -2°C and +3°C, where groundwater persists in the liquid phase for most of the year, in contrast to ARD in the periglacial belt where frost action dominates (MAAT < -2°C). The findings clearly suggest that the ambient air temperature is an important factor affecting the ARD production in alpine periglacial environments. Applying the paleoecological analysis of morphological abnormalities in chironomids through the past millennium, we tested and rejected the hypothesis that unfavorable conditions for aquatic life in the ARD-stressed lakes are largely related to the temperature increase over recent decades, responsible for the enhanced release of ARD contaminants. Our results indicate that the ARDs generated in the catchments are of a long-lasting nature and the frequency of chironomid morphological deformities was significantly higher during the Little Ice Age (LIA) than during pre- or post-LIA periods, suggesting that lower water temperatures may increase the adverse impacts of ARD on aquatic invertebrates. This highlights that temperature-mediated modulations of the metabolism and life cycle of aquatic organisms should be considered when reconstructing long-term trends in the ecotoxicological state of lakes. © 2017 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Impacts of drought and crayfish invasion on stream ecosystem structure and function

USGS Publications Warehouse

Magoulick, Daniel D.

2014-01-01

Drought and seasonal drying can be important disturbance events in many small streams, leading to intermittent or isolated habitats. Many small streams contain crayfish populations that are often keystone or dominant species in these systems. I conducted an experiment in stream mesocosms to examine the effects of drought and potential ecological redundancy of a native and invasive crayfish species. I examined the effects of drought (drought or control) and crayfish presence (none, native crayfish Orconectes eupunctus or invasive crayfish Orconectes neglectus) on stream mesocosm structure and function (leaf breakdown, community metabolism, periphyton, sediment and chironomid densities) in a fully factorial design. Each mesocosm contained a deep and shallow section, and drought treatments had surface water present (5-cm depth) in deep sections where tiles and leaf packs were placed. Drought and crayfish presence did not interact for any response variable. Drought significantly reduced leaf breakdown, and crayfish presence significantly increased leaf breakdown. However, the native and invasive crayfish species did not differ significantly in their effects on leaf breakdown. Drought significantly reduced primary production and community respiration overall, whereas crayfish presence did not significantly affect primary production and community respiration. Neither drought nor crayfish presence significantly affected periphyton overall. However, drought significantly reduced autotrophic index (AI), and crayfish presence increased AI. Inorganic sediment and chironomid density were not affected by drought, but both were significantly reduced by crayfish presence. O. eupunctus reduced AI and sediment more than O. neglectus did. Neither drought nor crayfish species significantly affected crayfish growth or survival. Drought can have strong effects on ecosystem function, but weaker effects on benthic structure. Crayfish can have strong effects on ecosystem structure and function regardless of drought. In stream mesocosms, native and invasive crayfish species appeared largely ecologically redundant, although subtle differences in crayfish effects could cascade throughout the food web, and further research is needed to address this question. 

The cell biology of Drosophila wing metamorphosis in vitro.

PubMed

Milner, Martin J; Muir, Jonathan

1987-03-01

We have examined the metamorphosis of the wing imaginal disc of Drosophila during culture in vitro in the continuous presence of 20-hydroxy ecdysone (0.1 μg/ ml). We find that the sequence of cellular changes in the wing blade during culture closely match those occurring in situ, involving two periods at which the dorsal and ventral surfaces are joined only by cell processes containing trans-alar microtubule arrays. Good pupal and imaginal cuticle secretion is found in this system.

The effect of phorate on wetland macroinvertebrates

USGS Publications Warehouse

Dieter, Charles D.; Flake, Lester D.; Duffy, Walter G.

1996-01-01

The effects of phorate, an organophosphorus insecticide, on aquatic macroinvertebrates was studied in littoral mesocosms in South Dakota wetlands. In 1991 and 1992, four mesocosms were constructed in each of three wetlands. In each wetland, one mesocosm was a reference and phorate concentrations of 1.2, 2.4, and 4.8 kg/ha were applied to treatment mesocosms. Phorate caused mortality to amphipods and chironomids throughout the study. Leeches and snails were resistant to phorate. Few living macroinvertebrates were present in mesocosms after phorate treatment and populations recovered only slightly after 1 month. Macroinvertebrate taxa that were sensitive to phorate included: Odonata, Hemiptera, Culicidae, Heliidae, Ephemeroptera, Acarina, Coleoptera, Stratio-myidae, and Hydracarina. Taxa that were tolerant to phorate included: Hirudinea, Gastropoda, Oligochaeta, and Ostracoda.

Unusual larval habitats and life history of chironomid (Diptera) genera

USGS Publications Warehouse

Hudson, Patrick L.

1987-01-01

Ninety-three genera, representing all subfamilies of Chironomidae, are organized into 9 categories of unusual habitats or life history including hygropetric, riparian (bank, floodplain, upland), hyporheic, symbiotic, and intertidal; others live in water held in plants or mine into unusual substrates. In riparian zones precise location of optimum habitat is difficult to determine as is definition of habitat within the continuum from shoreline to upland areas. The ecological importance of the riparian group appears to lie in its processing of coarse particulate matter along the floodplain of streams and rivers. All riparian genera are zoogeographically useful and can be used in reconstructing evolutionary dispersal pathways because they are adapted to unique habits that have remained largely undisturbed by human activities.

The Splice Isoforms of the Drosophila Ecdysis Triggering Hormone Receptor Have Developmentally Distinct Roles

PubMed Central

Diao, Feici; Mena, Wilson; Shi, Jonathan; Park, Dongkook; Diao, Fengqiu; Taghert, Paul; Ewer, John; White, Benjamin H.

2016-01-01

To grow, insects must periodically shed their exoskeletons. This process, called ecdysis, is initiated by the endocrine release of Ecdysis Trigger Hormone (ETH) and has been extensively studied as a model for understanding the hormonal control of behavior. Understanding how ETH regulates ecdysis behavior, however, has been impeded by limited knowledge of the hormone’s neuronal targets. An alternatively spliced gene encoding a G-protein-coupled receptor (ETHR) that is activated by ETH has been identified, and several lines of evidence support a role in ecdysis for its A-isoform. The function of a second ETHR isoform (ETHRB) remains unknown. Here we use the recently introduced “Trojan exon” technique to simultaneously mutate the ETHR gene and gain genetic access to the neurons that express its two isoforms. We show that ETHRA and ETHRB are expressed in largely distinct subsets of neurons and that ETHRA- but not ETHRB-expressing neurons are required for ecdysis at all developmental stages. However, both genetic and neuronal manipulations indicate an essential role for ETHRB at pupal and adult, but not larval, ecdysis. We also identify several functionally important subsets of ETHR-expressing neurons including one that coexpresses the peptide Leucokinin and regulates fluid balance to facilitate ecdysis at the pupal stage. The general strategy presented here of using a receptor gene as an entry point for genetic and neuronal manipulations should be useful in establishing patterns of functional connectivity in other hormonally regulated networks. PMID:26534952

Prospecting of popcorn hybrids for resistance to fall armyworm.

PubMed

Crubelati-Mulati, N C S; Scapim, C A; Albuquerque, F A; Amaral Junior, A T; Vivas, M; Rodovalho, M A

2014-08-26

The fall armyworm, Spodoptera frugiperda, is the pest that causes the greatest economic losses for both common corn and popcorn crops, and the use of resistant plant genotypes is an important tool for integrated pest management. The goal of the present study was to evaluate the damage caused by S. frugiperda on single-cross popcorn hybrids under field conditions with natural infestation as well as to study the effect of 11 popcorn hybrids on the S. frugiperda life cycle under laboratory conditions. A completely randomized block design with 4 replicates was used for the field experiment, and a completely randomized design with 10 replicates was used for the laboratory experiment. In the field experiment, the damage caused by fall armyworm, grain yield, and popping expansion were quantified, and a diallel analysis was performed to select the best hybrids. For the laboratory experiment, caterpillars were obtained from laboratory cultures kept on an artificial diet and were fed with leaves from the 11 hybrids. Hybrids P7.0 x P9.4, P7.1 x P9.6, P7.2.0 x P9.3, P7.4.0 x P9.1 and P7.4.1 x P9.4 exhibited negative specific combining ability for injury by fall armyworm and positive specific combining ability for yield and popping expansion. In the laboratory experiment, the hybrids influenced the mean larval stage duration, mean larval mass, final larval mass, pupal stage duration, mean pupal mass, and adult longevity.

Isolation and characterization of Nylanderia fulva virus 1, a positive-sense, single-stranded RNA virus infecting the tawny crazy ant, Nylanderia fulva

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

Valles, Steven M., E-mail: steven.valles@ars.usda.gov; Oi, David H.; Becnel, James J.

We report the discovery of Nylanderia fulva virus 1 (NfV-1), the first virus identified and characterized from the ant, Nylanderia fulva. The NfV-1 genome (GenBank accession KX024775) is 10,881 nucleotides in length, encoding one large open reading frame (ORF). Helicase, protease, RNA-dependent RNA polymerase, and jelly-roll capsid protein domains were recognized within the polyprotein. Phylogenetic analysis placed NfV-1 in an unclassified clade of viruses. Electron microscopic examination of negatively stained samples revealed particles with icosahedral symmetry with a diameter of 28.7±1.1 nm. The virus was detected by RT-PCR in larval, pupal, worker and queen developmental stages. However, the replicative strandmore » of NfV-1 was only detected in larvae. Vertical transmission did not appear to occur, but horizontal transmission was facile. The inter-colonial field prevalence of NfV-1 was 52±35% with some local infections reaching 100%. NfV-1 was not detected in limited samples of other Nylanderia species or closely related ant species. - Highlights: • A new positive-strand RNA virus was discovered in the ant, Nylanderia fulva. • The Nylanderia fulva virus 1 genome was comprised of 10,881 nucleotides. • NfV-1 was detected in larval, pupal, queen and worker ants, but not eggs. • Replication of NfV-1 appeared to be limited to the larval stage.« less

Cardiac optogenetic pacing in drosophila melanogaster using red-shifted opsins (Conference Presentation)

NASA Astrophysics Data System (ADS)

Men, Jing; Li, Airong; Jerwick, Jason; Tanzi, Rudolph E.; Zhou, Chao

2017-02-01

Electrical pacing is the current gold standard for investigation of mammalian cardiac electrical conduction systems as well as for treatment of certain cardiac pathologies. However, this method requires an invasive surgical procedure to implant the pacing electrodes. Recently, optogenetic pacing has been developed as an alternative, non-invasive method for heartbeat pacing in animals. It induces heartbeats by shining pulsed light on transgene-generated microbial opsins which in turn activate light gated ion channels in animal hearts. However, commonly used opsins, such as channelrhodopsin-2 (ChR2), require short light wavelength stimulation (475 nm), which is strongly absorbed and scattered by tissue. Here, we expressed recently engineered red-shifted opsins, ReaChR and CsChrimson, in the heart of a well-developed animal model, Drosophila melanogaster, for the first time. Optogenetic pacing was successfully conducted in both ReaChR and CsChrimson flies at their larval, pupal, and adult stages using 617 nm excitation light pulse, enabling a much deeper tissue penetration compared to blue stimulation light. A customized high speed and ultrahigh resolution OCM system was used to non-invasively monitor the heartbeat pacing in Drosophila. Compared to previous studies on optogenetic pacing of Drosophila, higher penetration depth of optogenetic excitation light was achieved in opaque late pupal flies. Lower stimulating power density is needed for excitation at each developmental stage of both groups, which improves the safety of this technique for heart rhythm studies.

Juvenile hormone counteracts the bHLH-PAS transcription factors MET and GCE to prevent caspase-dependent programmed cell death in Drosophila.

PubMed

Liu, Ying; Sheng, Zhentao; Liu, Hanhan; Wen, Di; He, Qianyu; Wang, Sheng; Shao, Wei; Jiang, Rong-Jing; An, Shiheng; Sun, Yaning; Bendena, William G; Wang, Jian; Gilbert, Lawrence I; Wilson, Thomas G; Song, Qisheng; Li, Sheng

2009-06-01

Juvenile hormone (JH) regulates many developmental and physiological events in insects, but its molecular mechanism remains conjectural. Here we report that genetic ablation of the corpus allatum cells of the Drosophila ring gland (the JH source) resulted in JH deficiency, pupal lethality and precocious and enhanced programmed cell death (PCD) of the larval fat body. In the fat body of the JH-deficient animals, Dronc and Drice, two caspase genes that are crucial for PCD induced by the molting hormone 20-hydroxyecdysone (20E), were significantly upregulated. These results demonstrated that JH antagonizes 20E-induced PCD by restricting the mRNA levels of Dronc and Drice. The antagonizing effect of JH on 20E-induced PCD in the fat body was further confirmed in the JH-deficient animals by 20E treatment and RNA interference of the 20E receptor EcR. Moreover, MET and GCE, the bHLH-PAS transcription factors involved in JH action, were shown to induce PCD by upregulating Dronc and Drice. In the Met- and gce-deficient animals, Dronc and Drice were downregulated, whereas in the Met-overexpression fat body, Dronc and Drice were significantly upregulated leading to precocious and enhanced PCD, and this upregulation could be suppressed by application of the JH agonist methoprene. For the first time, we demonstrate that JH counteracts MET and GCE to prevent caspase-dependent PCD in controlling fat body remodeling and larval-pupal metamorphosis in Drosophila.

Mixture-amount design and response surface modeling to assess the effects of flavonoids and phenolic acids on developmental performance of Anastrepha ludens.

PubMed

Pascacio-Villafán, Carlos; Lapointe, Stephen; Williams, Trevor; Sivinski, John; Niedz, Randall; Aluja, Martín

2014-03-01

Host plant resistance to insect attack and expansion of insect pests to novel hosts may to be modulated by phenolic compounds in host plants. Many studies have evaluated the role of phenolics in host plant resistance and the effect of phenolics on herbivore performance, but few studies have tested the joint effect of several compounds. Here, we used mixture-amount experimental design and response surface modeling to study the effects of a variety of phenolic compounds on the development and survival of Mexican fruit fly (Anastrepha ludens [Loew]), a notorious polyphagous pest of fruit crops that is likely to expand its distribution range under climate change scenarios. (+)- Catechin, phloridzin, rutin, chlorogenic acid, and p-coumaric acid were added individually or in mixtures at different concentrations to a laboratory diet used to rear individuals of A. ludens. No effect was observed with any mixture or concentration on percent pupation, pupal weight, adult emergence, or survival from neonate larvae to adults. Larval weight, larval and pupal developmental time, and the prevalence of adult deformities were affected by particular mixtures and concentrations of the compounds tested. We suggest that some combinations/concentrations of phenolic compounds could contribute to the management of A. ludens. We also highlight the importance of testing mixtures of plant secondary compounds when exploring their effects upon insect herbivore performance, and we show that mixture-amount design is a useful tool for this type of experiments.

Comparative life tables of leek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae), in its native range.

PubMed

Jenner, W H; Kuhlmann, U; Mason, P G; Cappuccino, N

2010-02-01

Leek moth, Acrolepiopsis assectella (Zeller) (Lepidoptera: Acrolepiidae), is an invasive alien species in eastern Canada, the larvae of which mine the green tissues of Allium spp. This study was designed to construct and analyse life tables for leek moth within its native range. Stage-specific mortality rates were estimated for the third leek moth generation at three sites in Switzerland from 2004 to 2006 to identify some of the principle factors that inhibit leek moth population growth in areas of low pest density. The contribution of natural enemies to leek moth mortality was measured by comparing mortality on caged and uncaged leeks. Total pre-imaginal mortality on uncaged plants was 99.6%, 99.1% and 96.4% in 2004, 2005 and 2006, respectively. Variation in mortality was greater among years than among sites. Total larval mortality was greater than that in the eggs and pupae. This was due largely to the high mortality (up to 83.3%) of neonates during the brief period between egg hatch and establishment of the feeding mine. Leek moth pupal mortality was significantly greater on uncaged than on caged leeks, indicating an impact by natural enemies, and this pattern was consistent over all three years of study. In contrast, the other life stages did not show consistently higher mortality rates on uncaged plants. This observation suggests that the pupal stage may be particularly vulnerable to natural enemies and, therefore, may be the best target for classical biological control in Canada.

FGF /FGFR Signal Induces Trachea Extension in the Drosophila Visual System

PubMed Central

Chu, Wei-Chen; Lee, Yuan-Ming; Henry Sun, Yi

2013-01-01

The Drosophila compound eye is a large sensory organ that places a high demand on oxygen supplied by the tracheal system. Although the development and function of the Drosophila visual system has been extensively studied, the development and contribution of its tracheal system has not been systematically examined. To address this issue, we studied the tracheal patterns and developmental process in the Drosophila visual system. We found that the retinal tracheae are derived from air sacs in the head, and the ingrowth of retinal trachea begin at mid-pupal stage. The tracheal development has three stages. First, the air sacs form near the optic lobe in 42-47% of pupal development (pd). Second, in 47-52% pd, air sacs extend branches along the base of the retina following a posterior-to-anterior direction and further form the tracheal network under the fenestrated membrane (TNUFM). Third, the TNUFM extend fine branches into the retina following a proximal-to-distal direction after 60% pd. Furthermore, we found that the trachea extension in both retina and TNUFM are dependent on the FGF(Bnl)/FGFR(Btl) signaling. Our results also provided strong evidence that the photoreceptors are the source of the Bnl ligand to guide the trachea ingrowth. Our work is the first systematic study of the tracheal development in the visual system, and also the first study demonstrating the interactions of two well-studied systems: the eye and trachea. PMID:23991208

Life history data on the fly parasitoids Aleochara nigra Kraatz and A. asiatica Kraatz (Coleoptera: Staphylinidae), and their potential application in forensic entomology.

PubMed

Lin, Shou-Wang; Shiao, Shiuh-Feng

2013-10-10

Knowledge of the developmental time of the immature stages of necrophagous flies has been the main tool for estimating minimum post-mortem intervals (min PMIs) in forensic entomology. Many parasitic insects can alter the development of immature stages of flies and thus affect min PMI estimates. The larvae of most species of Aleochara rove beetles are ectoparasitoids of the pupae of cyclorrhapha flies. Among them, some species that parasitise necrophagous flies may have forensic importance. Two Taiwanese Aleochara species, A. nigra and A. asiatica, which visit carrion sites were studied herein. All five necrophagous (Hemipyrellia ligurriens, Lucilia cuprina, Chrysomya megacephala, C. rufifacies and sarcophagid sp.) and one non-necrophagous fly species (Bactrocera dorsalis) we examined have the potential to be parasitised by these two Aleochara species, but differences among the acceptability and suitability of these hosts to rove beetle species suggested that rove beetles may prefer specific hosts. Each stage of the beetle life history was recorded to estimate developmental durations at six different temperatures. The larval stage together with the pupal stage of both beetle species was longer than the pupal stages of their hosts, implying the possibility of elongating the min PMI estimation. In addition, the host weight and larval duration of these two Aleochara beetles were positively correlated; thus, potential applications can be expected when using parasitised fly pupae in min PMI estimations. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Low-Temperature Stress during Capped Brood Stage Increases Pupal Mortality, Misorientation and Adult Mortality in Honey Bees

PubMed Central

Wang, Qing; Xu, Xinjian; Zhu, Xiangjie; Chen, Lin; Zhou, Shujing; Huang, Zachary Y.; Zhou, Bingfeng

2016-01-01

Honey bees (Apis mellifera) are key pollinators, playing a vital role in ecosystem maintenance and stability of crop yields. Recently, reduced honey bee survival has attracted intensive attention. Among all other honey bee stresses, temperature is a fundamental ecological factor that has been shown to affect honey bee survival. Yet, the impact of low temperature stress during capped brood on brood mortality has not been systematically investigated. In addition, little was known about how low temperature exposure during capped brood affects subsequent adult longevity. In this study, capped worker broods at 12 different developmental stages were exposed to 20°C for 12, 24, 36, 48, 60, 72, 84 and 96 hours, followed by incubation at 35°C until emergence. We found that longer durations of low temperature during capped brood led to higher mortality, higher incidences of misorientation inside cells and shorter worker longevity. Capped brood as prepupae and near emergence were more sensitive to low-temperature exposure, while capped larvae and mid-pupal stages showed the highest resistance to low-temperature stress. Our results suggest that prepupae and pupae prior to eclosion are the most sensitive stages to low temperature stress, as they are to other stresses, presumably due to many physiological changes related to metamorphosis happening during these two stages. Understanding how low-temperature stress affects honey bee physiology and longevity can improve honey bee management strategies. PMID:27149383

Does Tribolium brevicornis Cuticular Chemistry Deter Cannibalism and Predation of Pupae?

PubMed Central

Alabi, T; Dean, J; Michaud, JP; Verheggen, F; Lognay, G; Haubruge, E

2011-01-01

The cuticular hydrocarbons of insects are species-specific and often function as semiochemicals. The activity of Tribolium brevicornis cuticular hydrocarbons as feeding deterrents that ostensibly function to prevent pupal cannibalism and predation was evaluated. The cuticular hydrocarbons of T. brevicornis pupae were characterized and flour disk bioassays conducted with individual and combined extract components incorporated into artificial diets on which Tribolium adults fed for six days. Feeding by T. brevicornis and T. castaneum on flour disks containing cuticular extracts of T. brevicornis pupae resulted in reduced consumption and weight loss relative to feeding on control flour disks. In both cases, feeding deterrence indices exceeded 80% suggesting that T. brevicornis cuticular hydrocarbons could function to deter cannibalism and predation of pupae by larvae and adult beetles. Sixteen different cuticular hydrocarbons were identified in T. brevicornis pupal extracts. Eight of the commercially available linear alkanes were tested individually in feeding trials with eight Tribolium species. One compound (C28) significantly reduced the amount of food consumed by three species compared to control disks, whereas the compounds C25, C26, and C27 elicited increased feeding in some species. Four other compounds had no effect on consumption for any species. When four hydrocarbon mixtures were tested for synergistic deterrence on T. brevicornis and T. castaneum, none significantly influenced consumption. Our results indicate that the cuticular chemistry of T. brevicornis pupae could serve to deter predation by conspecific and congeneric beetles. PMID:22224957

Bar represses dPax2 and decapentaplegic to regulate cell fate and morphogenetic cell death in Drosophila eye.

PubMed

Kang, Jongkyun; Yeom, Eunbyul; Lim, Janghoo; Choi, Kwang-Wook

2014-01-01

The coordinated regulation of cell fate and cell survival is crucial for normal pattern formation in developing organisms. In Drosophila compound eye development, crystalline arrays of hexagonal ommatidia are established by precise assembly of diverse cell types, including the photoreceptor cells, cone cells and interommatidial (IOM) pigment cells. The molecular basis for controlling the number of cone and IOM pigment cells during ommatidial pattern formation is not well understood. Here we present evidence that BarH1 and BarH2 homeobox genes are essential for eye patterning by inhibiting excess cone cell differentiation and promoting programmed death of IOM cells. Specifically, we show that loss of Bar from the undifferentiated retinal precursor cells leads to ectopic expression of Prospero and dPax2, two transcription factors essential for cone cell specification, resulting in excess cone cell differentiation. We also show that loss of Bar causes ectopic expression of the TGFβ homolog Decapentaplegic (Dpp) posterior to the morphogenetic furrow in the larval eye imaginal disc. The ectopic Dpp expression is not responsible for the formation of excess cone cells in Bar loss-of-function mutant eyes. Instead, it causes reduction in IOM cell death in the pupal stage by antagonizing the function of pro-apoptotic gene reaper. Taken together, this study suggests a novel regulatory mechanism in the control of developmental cell death in which the repression of Dpp by Bar in larval eye disc is essential for IOM cell death in pupal retina.

Development of the Drosophila entero-endocrine lineage and its specification by the Notch signaling pathway

PubMed Central

Takashima, Shigeo; Adams, Katrina L.; Ortiz, Paola A.; Ying, Chong T.; Moridzadeh, Rameen; Younossi-Hartenstein, Amelia; Hartenstein, Volker

2013-01-01

In this paper we have investigated the developmental-genetic steps that shape the entero-endocrine system of Drosophila melanogaster from the embryo to the adult. The process starts in the endoderm of the early embryo where precursors of endocrine cells and enterocytes of the larval midgut, as well as progenitors of the adult midgut, are specified by a Notch signaling-dependent mechanism. In a second step that occurs during the late larval period, enterocytes and endocrine cells of a transient pupal midgut are selected from within the clusters of adult midgut progenitors. As in the embryo, activation of the Notch pathway triggers enterocyte differentiation, and inhibits cells from further proliferation or choosing the endocrine fate. The third step of entero-endocrine cell development takes place at a mid-pupal stage. Before this time point, the epithelial layer destined to become the adult midgut is devoid of endocrine cells. However, precursors of the intestinal midgut stem cells (pISCs) are already present. After an initial phase of symmetric divisions which causes an increase in their own population size, pISCs start to spin off cells that become postmitotic and express the endocrine fate marker, Prospero. Activation of Notch in pISCs forces these cells into an enterocyte fate. Loss of Notch function causes an increase in the proliferatory activity of pISCs, as well as a higher ratio of Prospero-positive cells. PMID:21382366

Developmental and hormone-induced changes of mitochondrial electron transport chain enzyme activities during the last instar larval development of maize stem borer, Chilo partellus (Lepidoptera: Crambidae).

PubMed

VenkatRao, V; Chaitanya, R K; Naresh Kumar, D; Bramhaiah, M; Dutta-Gupta, A

2016-12-01

The energy demand for structural remodelling in holometabolous insects is met by cellular mitochondria. Developmental and hormone-induced changes in the mitochondrial respiratory activity during insect metamorphosis are not well documented. The present study investigates activities of enzymes of mitochondrial electron transport chain (ETC) namely, NADH:ubiquinone oxidoreductase or complex I, Succinate: ubiquinone oxidoreductase or complex II, Ubiquinol:ferricytochrome c oxidoreductase or complex III, cytochrome c oxidase or complex IV and F 1 F 0 ATPase (ATPase), during Chilo partellus development. Further, the effect of juvenile hormone (JH) analog, methoprene, and brain and corpora-allata-corpora-cardiaca (CC-CA) homogenates that represent neurohormones, on the ETC enzyme activities was monitored. The enzymatic activities increased from penultimate to last larval stage and thereafter declined during pupal development with an exception of ATPase which showed high enzyme activity during last larval and pupal stages compared to the penultimate stage. JH analog, methoprene differentially modulated ETC enzyme activities. It stimulated complex I and IV enzyme activities, but did not alter the activities of complex II, III and ATPase. On the other hand, brain homogenate declined the ATPase activity while the injected CC-CA homogenate stimulated complex I and IV enzyme activities. Cumulatively, the present study is the first to show that mitochondrial ETC enzyme system is under hormone control, particularly of JH and neurohormones during insect development. Copyright © 2015 Elsevier Inc. All rights reserved.

Molting and cuticle deposition in the subterranean trichoniscid Titanethes albus (Crustacea, Isopoda)

PubMed Central

Vittori, Miloš; Kostanjšek, Rok; Žnidaršič, Nada; Štrus, Jasna

2012-01-01

Abstract Terrestrial isopods are a suitable group for the study of cuticle synthesis and calcium dynamics because they molt frequently and have evolved means to store calcium during molt. Little data is currently available on molting in Synocheta and subterranean isopods. We studied the molting dynamics in the subterranean trichoniscid Titanethes albus under laboratory conditions and performed a microscopic investigation of sternal CaCO3 deposits and the tergal epithelium during molt in this species. In accordance with its lower metabolic rate, molting in the laboratory is roughly 2–3 times less frequent in Titanethes albus than would be expected for an epigean isopod under similar conditions. Animals assumed characteristic postures following the molt of each body half and did not consume the posterior exuviae after posterior molt. The structure of sternal calcium deposits and the ultrastructural characteristics of the epidermis during cuticle formation in Titanethes albus are similar to those described in representatives of Ligiidae. During the deposition of the exocuticle, the apical plasma membrane of epidermal cells forms finger-like extensions and numerous invaginations. In the ecdysial space of individuals in late premolt we observed cellular extensions surrounded by bundles of tubules. PMID:22536097