Odour maps in the brain of butterflies with divergent host-plant preferences.

PubMed

Carlsson, Mikael A; Bisch-Knaden, Sonja; Schäpers, Alexander; Mozuraitis, Raimondas; Hansson, Bill S; Janz, Niklas

2011-01-01

Butterflies are believed to use mainly visual cues when searching for food and oviposition sites despite that their olfactory system is morphologically similar to their nocturnal relatives, the moths. The olfactory ability in butterflies has, however, not been thoroughly investigated. Therefore, we performed the first study of odour representation in the primary olfactory centre, the antennal lobes, of butterflies. Host plant range is highly variable within the butterfly family Nymphalidae, with extreme specialists and wide generalists found even among closely related species. Here we measured odour evoked Ca(2+) activity in the antennal lobes of two nymphalid species with diverging host plant preferences, the specialist Aglais urticae and the generalist Polygonia c-album. The butterflies responded with stimulus-specific combinations of activated glomeruli to single plant-related compounds and to extracts of host and non-host plants. In general, responses were similar between the species. However, the specialist A. urticae responded more specifically to its preferred host plant, stinging nettle, than P. c-album. In addition, we found a species-specific difference both in correlation between responses to two common green leaf volatiles and the sensitivity to these compounds. Our results indicate that these butterflies have the ability to detect and to discriminate between different plant-related odorants.

Odour Maps in the Brain of Butterflies with Divergent Host-Plant Preferences

PubMed Central

Schäpers, Alexander; Mozuraitis, Raimondas; Hansson, Bill S.; Janz, Niklas

2011-01-01

Butterflies are believed to use mainly visual cues when searching for food and oviposition sites despite that their olfactory system is morphologically similar to their nocturnal relatives, the moths. The olfactory ability in butterflies has, however, not been thoroughly investigated. Therefore, we performed the first study of odour representation in the primary olfactory centre, the antennal lobes, of butterflies. Host plant range is highly variable within the butterfly family Nymphalidae, with extreme specialists and wide generalists found even among closely related species. Here we measured odour evoked Ca2+ activity in the antennal lobes of two nymphalid species with diverging host plant preferences, the specialist Aglais urticae and the generalist Polygonia c-album. The butterflies responded with stimulus-specific combinations of activated glomeruli to single plant-related compounds and to extracts of host and non-host plants. In general, responses were similar between the species. However, the specialist A. urticae responded more specifically to its preferred host plant, stinging nettle, than P. c-album. In addition, we found a species-specific difference both in correlation between responses to two common green leaf volatiles and the sensitivity to these compounds. Our results indicate that these butterflies have the ability to detect and to discriminate between different plant-related odorants. PMID:21901154

Organic photovoltaic cells utilizing ultrathin sensitizing layer

DOEpatents

Forrest, Stephen R [Ann Arbor, MI; Yang, Fan [Piscataway, NJ; Rand, Barry P [Somers, NY

2011-09-06

A photosensitive device includes a plurality of organic photoconductive materials disposed in a stack between a first electrode and a second electrode, including a first continuous layer of donor host material, a second continuous layer of acceptor host material, and at least one other organic photoconductive material disposed as a plurality of discontinuous islands between the first continuous layer and the second continuous layer. Each of these other photoconductive materials has an absorption spectra different from the donor host material and the acceptor host material. Preferably, each of the discontinuous islands consists essentially of a crystallite of the respective organic photoconductive material, and more preferably, the crystallites are nanocrystals.

Comparison of emerald ash borer preference for ash of different species, sun exposure, age, and stress treatments in relation to foliar volatiles and nutrition

Treesearch

Therese M. Poland; Deepa S. Pureswaran; Yigen Chen

2009-01-01

We investigated the host selection behavior and feeding preference of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) on six different species of ash including Manchurian ash (F...

Infection with an acanthocephalan manipulates an amphipod's reaction to a fish predator's odours.

PubMed

Baldauf, Sebastian A; Thünken, Timo; Frommen, Joachim G; Bakker, Theo C M; Heupel, Oliver; Kullmann, Harald

2007-01-01

Many parasites with complex life cycles increase the chances of reaching a final host by adapting strategies to manipulate their intermediate host's appearance, condition or behaviour. The acanthocephalan parasite Pomphorhynchus laevis uses freshwater amphipods as intermediate hosts before reaching sexual maturity in predatory fish. We performed a series of choice experiments with infected and uninfected Gammarus pulex in order to distinguish between the effects of visual and olfactory predator cues on parasite-induced changes in host behaviour. When both visual and olfactory cues, as well as only olfactory cues were offered, infected and uninfected G. pulex showed significantly different preferences for the predator or the non-predator side. Uninfected individuals significantly avoided predator odours while infected individuals significantly preferred the side with predator odours. When only visual contact with a predator was allowed, infected and uninfected gammarids behaved similarly and had no significant preference. Thus, we believe we show for the first time that P. laevis increases its chance to reach a final host by olfactory-triggered manipulation of the anti-predator behaviour of its intermediate host.

The use of olfactory and visual cues in host choice by the capsid bugs Lygus rugulipennis Poppius and Liocoris tripustulatus fabricius.

PubMed

Wynde, Fiona J H; Port, Gordon R

2012-01-01

Lygus rugulipennis Poppius and Liocoris tripustulatus Fabricius (Heteroptera: Miridae) are pests of glasshouse cucumber and sweet pepper crops respectively. L. rugulipennis has a wide range of foodplants, but L. tripustulatus is specialised with very few food plants. We report behavioural assessments to investigate whether either species exhibits a preference for salad over wild hosts, and whether the role of olfaction and vision in response to cues from host plants can be distinguished. Olfactory responses to leaves were tested in choice chambers. L. rugulipennis was presented nettle (wild host) and a salad leaf of cucumber or sweet pepper, where the salad leaves had higher nitrogen content. L. tripustulatus was tested with nettle and sweet pepper of two different nitrogen contents. Female L. rugulipennis spent more time on the cucumber salad host, and chose it first most often, but males showed no preference. Neither sex discriminated between sweet pepper or nettle leaves, but males made more first contacts with sweet pepper. Neither sex of L. tripustulatus discriminated between sweet pepper and nettle leaves when the sweet pepper had higher nitrogen. When the plant species contained equivalent nitrogen both sexes spent more time on nettle. There was no difference in first choice made by either sex. When visual stimuli were available, and leaves had equivalent nitrogen, L. rugulipennis showed no preference and L. tripustulatus preferred nettle leaves. We conclude that the generalist L. rugulipennis has the ability to use remote olfactory cues for host choice whereas the specialist L. tripustulatus relies mainly on contact chemosensory and gustatory cues.

The Use of Olfactory and Visual Cues in Host Choice by the Capsid Bugs Lygus rugulipennis Poppius and Liocoris tripustulatus Fabricius

PubMed Central

Wynde, Fiona J. H.; Port, Gordon R.

2012-01-01

Lygus rugulipennis Poppius and Liocoris tripustulatus Fabricius (Heteroptera: Miridae) are pests of glasshouse cucumber and sweet pepper crops respectively. L. rugulipennis has a wide range of foodplants, but L. tripustulatus is specialised with very few food plants. We report behavioural assessments to investigate whether either species exhibits a preference for salad over wild hosts, and whether the role of olfaction and vision in response to cues from host plants can be distinguished. Olfactory responses to leaves were tested in choice chambers. L. rugulipennis was presented nettle (wild host) and a salad leaf of cucumber or sweet pepper, where the salad leaves had higher nitrogen content. L. tripustulatus was tested with nettle and sweet pepper of two different nitrogen contents. Female L. rugulipennis spent more time on the cucumber salad host, and chose it first most often, but males showed no preference. Neither sex discriminated between sweet pepper or nettle leaves, but males made more first contacts with sweet pepper. Neither sex of L. tripustulatus discriminated between sweet pepper and nettle leaves when the sweet pepper had higher nitrogen. When the plant species contained equivalent nitrogen both sexes spent more time on nettle. There was no difference in first choice made by either sex. When visual stimuli were available, and leaves had equivalent nitrogen, L. rugulipennis showed no preference and L. tripustulatus preferred nettle leaves. We conclude that the generalist L. rugulipennis has the ability to use remote olfactory cues for host choice whereas the specialist L. tripustulatus relies mainly on contact chemosensory and gustatory cues. PMID:23226493

Leg structure explains host site preference in bat flies (Diptera: Streblidae) parasitizing neotropical bats (Chiroptera: Phyllostomidae).

PubMed

Hiller, Thomas; Honner, Benjamin; Page, Rachel A; Tschapka, Marco

2018-03-22

Bat flies (Streblidae) are diverse, obligate blood-feeding insects and probably the most conspicuous ectoparasites of bats. They show preferences for specific body regions on their host bat, which are reflected in behavioural characteristics. In this study, we corroborate the categorization of bat flies into three ecomorphological groups, focusing only on differences in hind leg morphology. As no detailed phylogeny of bat flies is available, it remains uncertain whether these morphological differences reflect the evolutionary history of bat flies or show convergent adaptations for the host habitat type. We show that the division of the host bat into three distinct habitats contributes to the avoidance of interspecific competition of bat fly species. Finally, we found evidence for density-dependent competition between species belonging to the same ecomorphological group.

Host Plant Adaptation in Drosophila mettleri Populations

PubMed Central

Castrezana, Sergio; Bono, Jeremy M.

2012-01-01

The process of local adaptation creates diversity among allopatric populations, and may eventually lead to speciation. Plant-feeding insect populations that specialize on different host species provide an excellent opportunity to evaluate the causes of ecological specialization and the subsequent consequences for diversity. In this study, we used geographically separated Drosophila mettleri populations that specialize on different host cacti to examine oviposition preference for and larval performance on an array of natural and non-natural hosts (eight total). We found evidence of local adaptation in performance on saguaro cactus (Carnegiea gigantea) for populations that are typically associated with this host, and to chemically divergent prickly pear species (Opuntia spp.) in a genetically isolated population on Santa Catalina Island. Moreover, each population exhibited reduced performance on the alternative host. This finding is consistent with trade-offs associated with adaptation to these chemically divergent hosts, although we also discuss alternative explanations for this pattern. For oviposition preference, Santa Catalina Island flies were more likely to oviposit on some prickly pear species, but all populations readily laid eggs on saguaro. Experiments with non-natural hosts suggest that factors such as ecological opportunity may play a more important role than host plant chemistry in explaining the lack of natural associations with some hosts. PMID:22493678

Host plant adaptation in Drosophila mettleri populations.

PubMed

Castrezana, Sergio; Bono, Jeremy M

2012-01-01

The process of local adaptation creates diversity among allopatric populations, and may eventually lead to speciation. Plant-feeding insect populations that specialize on different host species provide an excellent opportunity to evaluate the causes of ecological specialization and the subsequent consequences for diversity. In this study, we used geographically separated Drosophila mettleri populations that specialize on different host cacti to examine oviposition preference for and larval performance on an array of natural and non-natural hosts (eight total). We found evidence of local adaptation in performance on saguaro cactus (Carnegiea gigantea) for populations that are typically associated with this host, and to chemically divergent prickly pear species (Opuntia spp.) in a genetically isolated population on Santa Catalina Island. Moreover, each population exhibited reduced performance on the alternative host. This finding is consistent with trade-offs associated with adaptation to these chemically divergent hosts, although we also discuss alternative explanations for this pattern. For oviposition preference, Santa Catalina Island flies were more likely to oviposit on some prickly pear species, but all populations readily laid eggs on saguaro. Experiments with non-natural hosts suggest that factors such as ecological opportunity may play a more important role than host plant chemistry in explaining the lack of natural associations with some hosts.

Geographic mosaics of species' association: a definition and an example driven by plant-insect phenological synchrony.

PubMed

Singer, Michael C; McBride, Carolyn S

2012-12-01

Spatial mosaics occur in both evolutionary and ecological properties of species' interactions. Studies of these patterns have facilitated description and prediction of evolutionary responses of interacting species to each other and to changing environments. We propose seeking complementary understanding of community assembly and dynamics by studying ecological and mechanistic properties of mosaics. We define "species' association mosaics" as deviations from a null model in which spatial variation in the extent to which particular species interact ecologically is explained solely by variation in their densities. In extreme deviations from the null, a focal species interacts exclusively with different partners at different sites despite similar abundances of potential partners. We investigate this type of mosaic involving the butterfly Euphydryas editha and its hosts, the perennial Pedicularis semibarbata (Psem) and the ephemeral annual Collinsia torreyi (Ctor). A reciprocal transplant experiment showed that the proximate, mechanistic driver of the mosaic was variation in butterfly oviposition preference: the identity of the preferred host species depended on the site of origin of the insects, not that of the plants. In contrast, the evolutionary driver was phenological asynchrony between the insects and Ctor. Censuses showed that larvae hatching from eggs laid on Ctor would have suffered significantly greater mortality from host senescence at five sites where Ctor was avoided than at two sites where it was used. These differences among sites in phenological synchrony were caused by variation in life span of Ctor. At sites where Ctor was avoided, natural selection on host preference was stabilizing because Ctor life span was too short to accommodate the development time of most larvae. At sites where Ctor was used, selection on preference was also stabilizing because larvae lacked physiological adaptation to feed on Psem. These reciprocal forces of stabilizing selection formed a mosaic maintaining spatial variation in insect host preference that was the proximate cause of the species-association mosaic. In the Discussion, we examine the extent to which our findings hindcast an observed anthropogenic host shift by E. editha from Psem to Ctor. This example shows that elucidation of species-association mosaics can facilitate understanding of community evolution and dynamics.

Factors Influencing Host Plant Choice and Larval Performance in Bactericera cockerelli

PubMed Central

Prager, Sean M.; Esquivel, Isaac; Trumble, John T.

2014-01-01

Among the many topics of interest to ecologists studying associations between phytophagous insects and their host plants are the influence of natal host plant on future oviposition decisions and the mechanisms of generalist versus specialist host selection behavior. In this study, we examined the oviposition preferences, behavior and larval development of the tomato/potato psyllid, Bactericera cockerelli. By rearing psyllids with two distinct geographically-linked haplotypes on different host plants, we were able to examine the role of natal host plant and potential local adaptation on host plant usage. Choice bioassays among three host species demonstrated that psyllids from California had clear preferences that were influenced by natal plant. We further found that patterns in choice bioassays corresponded to observed feeding and movement responses. No-choice bioassays demonstrated that there is little to no association between development and host-plant choice for oviposition, while also indicating that host choice varies between haplotypes. These findings support the concept that mothers do not always choose oviposition sites optimally and also add support for the controversial Hopkins' host selection principle. PMID:24710468

The influence of learning on host plant preference in a significant phytopathogen vector, Diaphorina citri

USDA-ARS?s Scientific Manuscript database

Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri, vector ...

Parent–offspring conflicts, “optimal bad motherhood” and the “mother knows best” principles in insect herbivores colonizing novel host plants

PubMed Central

García-Robledo, Carlos; Horvitz, Carol C

2012-01-01

Specialization of insect herbivores to one or a few host plants stimulated the development of two hypotheses on how natural selection should shape oviposition preferences: The “mother knows best” principle suggests that females prefer to oviposit on hosts that increase offspring survival. The “optimal bad motherhood” principle predicts that females prefer to oviposit on hosts that increase their own longevity. In insects colonizing novel host plants, current theory predicts that initial preferences of insect herbivores should be maladaptive, leading to ecological traps. Ecological trap theory does not take into account the fact that insect lineages frequently switch hosts at both ecological and evolutionary time scales. Therefore, the behavior of insect herbivores facing novel hosts is also shaped by natural selection. Using a study system in which four Cephaloleia beetles are currently expanding their diets from native to exotic plants in the order Zingiberales, we determined if initial oviposition preferences are conservative, maladaptive, or follow the patterns predicted by the “mother knows best” or the “optimal bad motherhood” principles. Interactions with novel hosts generated parent–offspring conflicts. Larval survival was higher on native hosts. However, adult generally lived longer on novel hosts. In Cephaloleia beetles, oviposition preferences are usually associated with hosts that increase larval survival, female fecundity, and population growth. In most cases, Cephaloleia oviposition preferences follow the expectations of the “mothers knows best” principle. PMID:22957153

Analyzing the Differences and Preferences of Pathogenic and Nonpathogenic Prokaryote Species

NASA Astrophysics Data System (ADS)

Nolen, L.; Duong, K.; Heim, N. A.; Payne, J.

2015-12-01

A limited amount of knowledge exists on the large-scale characteristics and differences of pathogenic species in comparison to all prokaryotes. Pathogenic species, like other prokaryotes, have attributes specific to their environment and lifestyles. However, because they have evolved to coexist inside their hosts, the conditions they occupy may be more limited than those of non-pathogenic species. In this study we investigate the possibility of divergent evolution between pathogenic and non-pathogenic species by examining differences that may have evolved as a result of the need to adapt to their host. For this research we analyzed data collected from over 1900 prokaryotic species and performed t-tests using R to quantify potential differences in preferences. To examine the possible divergences from nonpathogenic bacteria, we focused on three variables: cell biovolume, preferred environmental pH, and preferred environmental temperature. We also looked at differences between pathogenic and nonpathogenic species belonging to the same phylum. Our results suggest a strong divergence in abiotic preferences between the two groups, with pathogens occupying a much smaller range of temperatures and pHs than their non-pathogenic counterparts. However, while the median biovolume is different when comparing pathogens and nonpathogens, we cannot conclude that the mean values are significantly different from each other. In addition, we found evidence of convergent evolution, as the temperature and pH preferences of pathogenic bacteria species from different phlya all approach the same values. Pathogenic species do not, however, all approach the same biovolume values, suggesting that specific pH and temperature preferences are more characteristic of pathogens than certain biovolumes.

Are adaptation costs necessary to build up a local adaptation pattern?

PubMed

Magalhães, Sara; Blanchet, Elodie; Egas, Martijn; Olivieri, Isabelle

2009-08-03

Ecological specialization is pervasive in phytophagous arthropods. In such specialization mode, limits to host range are imposed by trade-offs preventing adaptation to several hosts. The occurrence of such trade-offs is inferred by a pattern of local adaptation, i.e., a negative correlation between relative performance on different hosts. To establish a causal link between local adaptation and trade-offs, we performed experimental evolution of spider mites on cucumber, tomato and pepper, starting from a population adapted to cucumber. Spider mites adapted to each novel host within 15 generations and no further evolution was observed at generation 25. A pattern of local adaptation was found, as lines evolving on a novel host performed better on that host than lines evolving on other hosts. However, costs of adaptation were absent. Indeed, lines adapted to tomato had similar or higher performance on pepper than lines evolving on the ancestral host (which represent the initial performance of all lines) and the converse was also true, e.g. negatively correlated responses were not observed on the alternative novel host. Moreover, adapting to novel hosts did not result in decreased performance on the ancestral host. Adaptation did not modify host ranking, as all lines performed best on the ancestral host. Furthermore, mites from all lines preferred the ancestral to novel hosts. Mate choice experiments indicated that crosses between individuals from the same or from a different selection regime were equally likely, hence development of reproductive isolation among lines adapted to different hosts is unlikely. Therefore, performance and preference are not expected to impose limits to host range in our study species. Our results show that the evolution of a local adaptation pattern is not necessarily associated with the evolution of an adaptation cost.

A Locus in Drosophila sechellia Affecting Tolerance of a Host Plant Toxin

PubMed Central

Hungate, Eric A.; Earley, Eric J.; Boussy, Ian A.; Turissini, David A.; Ting, Chau-Ti; Moran, Jennifer R.; Wu, Mao-Lien; Wu, Chung-I; Jones, Corbin D.

2013-01-01

Many insects feed on only one or a few types of host. These host specialists often evolve a preference for chemical cues emanating from their host and develop mechanisms for circumventing their host’s defenses. Adaptations like these are central to evolutionary biology, yet our understanding of their genetics remains incomplete. Drosophila sechellia, an emerging model for the genetics of host specialization, is an island endemic that has adapted to chemical toxins present in the fruit of its host plant, Morinda citrifolia. Its sibling species, D. simulans, and many other Drosophila species do not tolerate these toxins and avoid the fruit. Earlier work found a region with a strong effect on tolerance to the major toxin, octanoic acid, on chromosome arm 3R. Using a novel assay, we narrowed this region to a small span near the centromere containing 18 genes, including three odorant binding proteins. It has been hypothesized that the evolution of host specialization is facilitated by genetic linkage between alleles contributing to host preference and alleles contributing to host usage, such as tolerance to secondary compounds. We tested this hypothesis by measuring the effect of this tolerance locus on host preference behavior. Our data were inconsistent with the linkage hypothesis, as flies bearing this tolerance region showed no increase in preference for media containing M. citrifolia toxins, which D. sechellia prefers. Thus, in contrast to some models for host preference, preference and tolerance are not tightly linked at this locus nor is increased tolerance per se sufficient to change preference. Our data are consistent with the previously proposed model that the evolution of D. sechellia as a M. citrifolia specialist occurred through a stepwise loss of aversion and gain of tolerance to M. citrifolia’s toxins. PMID:24037270

Some like it hot: factors impacting thermal preferences of two Ponto-Caspian amphipods Dikerogammarus villosus (Sovinsky, 1894) and Dikerogammarus haemobaphes (Eichwald, 1841).

PubMed

Rachalewski, Michał; Kobak, Jarosław; Szczerkowska-Majchrzak, Eliza; Bącela-Spychalska, Karolina

2018-01-01

Temperature is a crucial factor determining biology and ecology of poikilothermic animals. It often constitutes an important barrier for invasive species originating from different climate zones but, on the other hand, may facilitate the invasion process of animals with wide thermal preferences and high resistance to extreme temperatures. In our experimental study, we investigated the thermal behaviour of two Ponto-Caspian amphipod crustaceans- Dikerogammarus villosus and Dikerogammarus haemobaphes . Both species are known to live under a wide range of thermal conditions which may promote their invasion. Moreover, both these amphipods are hosts for microsporidian parasites which co-evolved with them within the Ponto-Caspian region and spread in European waters. As the presence of a parasite may influence the thermal preferences of its host, we expected to observe behavioural changes in infected individuals of the studied amphipods leading to (1) behavioural fever (selecting a warmer habitat) or (2) anapyrexia (selecting a colder habitat). The experiment ( N  = 20) was carried out for 30 min in a 100 cm. 20 cm from boths sides were not avaliable for amphipods long thermal gradient (0-40 °C), using 30 randomly selected adult amphipod individuals of one species. At the end of each trial, we checked the position of amphipods along the gradient and determined their sex and infection status (uninfected or infected by one of microsporidium species). D. villosus was infected with Cucumispora dikerogammari whereas D. haemobaphes was a host for C. dikerogammari , Dictyocoela muelleri or D. berillonum . Thermal preferences of amphipods depended on their species and sex. Females of D. villosus preferred warmer microhabitats (often much above 30 °C) than conspecific males and females of D. haemobaphes , whereas no significant differences were found among males of both species and both sexes of D. haemobaphes . Moreover, infected males of D. villosus stayed in warmer water more often than uninfected males of this species, selecting temperatures higher than 30 °C, which may be explained either as a behavioural fever constituting a defence mechanism of a host against the infection, or as a parasite manipulation of the host behaviour increasing the parasite fitness. On the other hand, none of the parasite species affected the thermal preferences of D. haemobaphes , including also C. dikerogammari , changing the behaviour of D. villosus . Our research presents the complexity of the thermal behaviour of studied amphipods and the evidence that microsporidia may trigger a change in temperature preferendum of their host species and those observations may be the result of different host-parasite coevolution time which may vary for the two host species (Poulin, 2010).

Host preference and host colonization of the Asian long-horned beetle, Anoplophora glabripennis (Coleoptera Cerambycidae), in Southern Europe.

PubMed

Faccoli, M; Favaro, R

2016-06-01

The Asian long-horned beetle (ALB), Anoplophora glabripennis (Motschulsky), is a highly polyphagous invasive pest with a broad range of host species, but showing relevant differences between infestation areas. Host preference and host colonization (female fecundity, egg and larval survival) were assessed in a population in Northern Italy by choice and no-choice experiments conducted in both field and laboratory conditions. During 5 years of field observations, ALB was found to infest seven genera of trees: Acer, Aesculus, Betula, Populus, Prunus, Salix and Ulmus. However, Acer, Betula, Ulmus and Salix resulted to be the preferred hosts corresponding to 97.5% (1112) of the 1140 infested trees. In both laboratory and field trials carried out on these four host genera, no-choice experiments recorded the highest host colonization of A. glabripennis on Acer trees, with the highest number of laid eggs and the lowest egg and larval mortality. Ulmus and Salix showed a lower number of laid eggs during laboratory choice test, but egg and larval mortality had mean values similar to Acer. On the contrary, despite the high number of Betula trees felled during the eradication plan carried out in the infestation area, this tree species showed the lowest beetle suitability in terms of number of laid eggs and insect survival. An overestimation of the number of infested Betula occurring during the tree survey may explain the discordance between high number of infested Betula and low beetle suitability. Instead, the large number of infested Acer recorded in the field was probably due to the high abundance of these trees occurring in parks and gardens within the infestation area and to the low adult dispersal of A. glabripennis. Overall, results from this study confirm that host species affects both beetle colonization and breeding performance. The study shows ALB host preference and host suitability varying between tree species, suggesting an ALB acceptance even of sub-optimal hosts.

Herbivore Oral Secreted Bacteria Trigger Distinct Defense Responses in Preferred and Non-Preferred Host Plants.

PubMed

Wang, Jie; Chung, Seung Ho; Peiffer, Michelle; Rosa, Cristina; Hoover, Kelli; Zeng, Rensen; Felton, Gary W

2016-06-01

Insect symbiotic bacteria affect host physiology and mediate plant-insect interactions, yet there are few clear examples of symbiotic bacteria regulating defense responses in different host plants. We hypothesized that plants would induce distinct defense responses to herbivore- associated bacteria. We evaluated whether preferred hosts (horsenettle) or non-preferred hosts (tomato) respond similarly to oral secretions (OS) from the false potato beetle (FPB, Leptinotarsa juncta), and whether the induced defense triggered by OS was due to the presence of symbiotic bacteria in OS. Both horsenettle and tomato damaged by antibiotic (AB) treated larvae showed higher polyphenol oxidase (PPO) activity than those damaged by non-AB treated larvae. In addition, application of OS from AB treated larvae induced higher PPO activity compared with OS from non-AB treated larvae or water treatment. False potato beetles harbor bacteria that may provide abundant cues that can be recognized by plants and thus mediate corresponding defense responses. Among all tested bacterial isolates, the genera Pantoea, Acinetobacter, Enterobacter, and Serratia were found to suppress PPO activity in tomato, while only Pantoea sp. among these four isolates was observed to suppress PPO activity in horsenettle. The distinct PPO suppression caused by symbiotic bacteria in different plants was similar to the pattern of induced defense-related gene expression. Pantoea inoculated FPB suppressed JA-responsive genes and triggered a SA-responsive gene in both tomato and horsenettle. However, Enterobacter inoculated FPB eliminated JA-regulated gene expression and elevated SA-regulated gene expression in tomato, but did not show evident effects on the expression levels of horsenettle defense-related genes. These results indicate that suppression of plant defenses by the bacteria found in the oral secretions of herbivores may be a more widespread phenomenon than previously indicated.

The influence of prior experience on preference and performance of a cryptoparasitoid Scleroderma guani (Hymenoptera: Bethylidae) on beetle hosts

Treesearch

Li Li; Daniel R. Miller; Jianghua Sun

2010-01-01

1. Numerous studies have reported the effects of learning or experience on parasitoid host preference and location. However, the integration of pre-imaginal and adult experiences on the subsequent host preference and adult/offspring performance has been rarely tested in host–parasite interactions. 2. We present direct evidence that theses two kinds of experiences...

The Effects of Bean Leafroll Virus on Life History Traits and Host Selection Behavior of Specialized Pea Aphid (Acyrthosiphon pisum, Hemiptera: Aphididae) Genotypes.

PubMed

Davis, T S; Wu, Y; Eigenbrode, S D

2017-02-01

Intraspecific specialization by insect herbivores on different host plant species contributes to the formation of genetically distinct "host races," but the effects of plant virus infection on interactions between specialized herbivores and their host plants have barely been investigated. Using three genetically and phenotypically divergent pea aphid clones (Acyrthosiphon pisum L.) adapted to either pea (Pisum sativum L.) or alfalfa (Medicago sativa L.), we tested how infection of these hosts by an insect-borne phytovirus (Bean leafroll virus; BLRV) affects aphid performance and preference. Four important findings emerged: 1) mean aphid survival rate and intrinsic rate of population growth (Rm) were increased by 15% and 14%, respectively, for aphids feeding on plants infected with BLRV; 2) 34% of variance in survival rate was attributable to clone × host plant interactions; 3) a three-way aphid clone × host plant species × virus treatment significantly affected intrinsic rates of population growth; and 4) each clone exhibited a preference for either pea or alfalfa when choosing between noninfected host plants, but for two of the three clones tested these preferences were modestly reduced when selecting among virus-infected host plants. Our studies show that colonizing BLRV-infected hosts increased A. pisum survival and rates of population growth, confirming that the virus benefits A. pisum. BLRV transmission affected aphid discrimination of host plant species in a genotype-specific fashion, and we detected three unique "virus-association phenotypes," with potential consequences for patterns of host plant use by aphid populations and crop virus epidemiology. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Brucella Genetic Variability in Wildlife Marine Mammals Populations Relates to Host Preference and Ocean Distribution

PubMed Central

Suárez-Esquivel, Marcela; Baker, Kate S.; Ruiz-Villalobos, Nazareth; Hernández-Mora, Gabriela; Barquero-Calvo, Elías; González-Barrientos, Rocío; Castillo-Zeledón, Amanda; Jiménez-Rojas, César; Chacón-Díaz, Carlos; Cloeckaert, Axel; Chaves-Olarte, Esteban; Thomson, Nicholas R.; Moreno, Edgardo

2017-01-01

Abstract Intracellular bacterial pathogens probably arose when their ancestor adapted from a free-living environment to an intracellular one, leading to clonal bacteria with smaller genomes and less sources of genetic plasticity. Still, this plasticity is needed to respond to the challenges posed by the host. Members of the Brucella genus are facultative-extracellular intracellular bacteria responsible for causing brucellosis in a variety of mammals. The various species keep different host preferences, virulence, and zoonotic potential despite having 97–99% similarity at genome level. Here, we describe elements of genetic variation in Brucella ceti isolated from wildlife dolphins inhabiting the Pacific Ocean and the Mediterranean Sea. Comparison with isolates obtained from marine mammals from the Atlantic Ocean and the broader Brucella genus showed distinctive traits according to oceanic distribution and preferred host. Marine mammal isolates display genetic variability, represented by an important number of IS711 elements as well as specific IS711 and SNPs genomic distribution clustering patterns. Extensive pseudogenization was found among isolates from marine mammals as compared with terrestrial ones, causing degradation in pathways related to energy, transport of metabolites, and regulation/transcription. Brucella ceti isolates infecting particularly dolphin hosts, showed further degradation of metabolite transport pathways as well as pathways related to cell wall/membrane/envelope biogenesis and motility. Thus, gene loss through pseudogenization is a source of genetic variation in Brucella, which in turn, relates to adaptation to different hosts. This is relevant to understand the natural history of bacterial diseases, their zoonotic potential, and the impact of human interventions such as domestication. PMID:28854602

Oviposition Preference of Pea Weevil, Bruchus pisorum L. Among Host and Non-host Plants and its Implication for Pest Management

PubMed Central

Mendesil, Esayas; Rämert, Birgitta; Marttila, Salla; Hillbur, Ylva; Anderson, Peter

2016-01-01

The pea weevil, Bruchus pisorum L. is a major insect pest of field pea, Pisum sativum L. worldwide and current control practices mainly depend on the use of chemical insecticides that can cause adverse effects on environment and human health. Insecticides are also unaffordable by many small-scale farmers in developing countries, which highlights the need for investigating plant resistance traits and to develop alternative pest management strategies. The aim of this study was to determine oviposition preference of pea weevil among P. sativum genotypes with different level of resistance (Adet, 32410-1 and 235899-1) and the non-host leguminous plants wild pea (Pisum fulvum Sibth. et Sm.) and grass pea (Lathyrus sativus L.), in no-choice and dual-choice tests. Pod thickness and micromorphological traits of the pods were also examined. In the no-choice tests significantly more eggs were laid on the susceptible genotype Adet than on the other genotypes. Very few eggs were laid on P. fulvum and L. sativus. In the dual-choice experiments Adet was preferred by the females for oviposition. Furthermore, combinations of Adet with either 235899-1 or non-host plants significantly reduced the total number of eggs laid by the weevil in the dual-choice tests. Female pea weevils were also found to discriminate between host and non-host plants during oviposition. The neoplasm (Np) formation on 235899-1 pods was negatively correlated with oviposition by pea weevil. Pod wall thickness and trichomes might have influenced oviposition preference of the weevils. These results on oviposition behavior of the weevils can be used in developing alternative pest management strategies such as trap cropping using highly attractive genotype and intercropping with the non-host plants. PMID:26779220

Do mothers really know best? Complexities in testing the preference-performance hypothesis in polyphagous frugivorous fruit flies.

PubMed

Birke, A; Aluja, M

2017-12-04

The preference-performance hypothesis (PPH) has widely been used to explain host exploitation patterns by phytophagous insects. However, this hypothesis often fails in the case of polyphagous species when compared with specialists. One explanation, validated by the information-processing hypothesis (IPH), considers that polyphagous insects are unable to process a large array of cues, which hinders females from distinguishing between high- and low- quality hosts. Here we analyzed Anastrepha ludens female host preference and offspring performance, and tested if neuronal limitations could possibly play a role in the incapacity of the polyphagous A. ludens to make 'accurate decisions' and therefore partially explain mismatches related to PPH. Results testing the PPH by correlating female preference to six naturally occurring hosts and its offspring outcomes show that A. ludens females oviposited greater proportions of eggs on fruit according to hierarchical preferences. Infestation level was low in white sapote, the preferential and seemingly putative ancestral host, likely due to sapote defence mechanisms. Pupal weight and adult size were lower when A. ludens larvae developed in guava (conditional host that was artificially infested) and peach, a lower ranked host compared with 'Marsh' grapefruit, white sapote, and 'Manila' mango (three preferred hosts). Larvae reared in 'Manzano' pepper, a low-ranked host, performed better than in peach and guava. Results testing the IPH, show that polyphagous A. ludens females were less accurate when discerning between a non natural host (guava) when compared with a preferred, natural host (grapefruit): error rate was significantly higher, number of oviposited fruit in a 6-h period was extremely low, time searching and ovipositing took longer, and pupae recovery was extremely low. Our findings indicate that both hypotheses tested are complementary and help better understand host use by A. ludens. However, we also discuss the complexity of polyphagy considering other factors such as plant resistance/defence mechanisms which are not fully addressed in both theories tested.

Attraction of some scolytids and associated beetles to the host volatiles α-pinene and ethanol

Treesearch

Leif Martin Schroeder

1991-01-01

Several scolytid species are known to use host volatiles such as monoterpenes and the degradation product, ethanol, when searching for suitable host material. The release rates of terpenes and ethanol and the proportions in which they are released can be expected to differ depending on the breeding substrate preferences of the various scolytid species. The aim of this...

The whole genome sequence of the Mediterranean fruit fly, Ceratitis capitata (Wiedmann), reveals insights into the biology and adaptive evolution of a highly invasive pest species

USDA-ARS?s Scientific Manuscript database

The Mediterranean fruit fly is one of the most destructive agricultural pests throughout the world due to its broad host plant range that includes more than 260 different fruits, flowers, vegetables, and nuts. Host preferences vary in different regions of the world, which can be associated with its ...

Host preference, population growth and injuries assessment of Polyphagotarsonemus latus (banks) (ACARI: Tarsonemidae) on Capsicum annuum L. Genotypes.

PubMed

Breda, M O; de Oliveira, J V; Esteves Filho, A B; Barbosa, D R S; de Santana, M F

2016-10-01

Despite the continued efforts on the search for different genotypes, Capsicum annuum (L.) is quite susceptible to attack by pest arthropods, especially the broad mite Polyphagotarsonemus latus Banks. Thus, the host preference, population growth and the injuries assessment of P. latus was studied on six C. annuum genotypes used in Brazil (Atlantis, California Wonder, Impact, Palloma, Rubia and Tendence). Host preference was accessed in choice tests, pairing the several genotypes, and the population growth was observed through non-choice tests in laboratory. The injuries assessments were evaluated in the greenhouse, comparing the injury level among the six genotypes. The results indicate that California Wonder and Palloma genotypes were more preferred by P. latus, and Impact and Tendence were less preferred. P. latus presented positive population growth rates (ri) on all the genotypes, however, Palloma and California Wonder showed the highest values of population growth rate (ri = 0.344 and ri = 0.340, respectively), while Impact had the lowest value (ri = 0.281). All the evaluated C. annuum genotypes showed low tolerance to P. latus and exhibited several injuries, but there was no statistical difference between them. California Wonder had the highest average number of mites/leaf (57.15), while Impact and Tendence obtained the lowest values (36.67 and 35.12, respectively) at the end of the evaluation period. The total average of injuries notes at the end of the bioassay did not differ between the genotypes. The number of mites/leaf was growing for the injury scale to the note 3.0, but when the injury scale approached the note 4.0, there was observed a decrease in the number of mites/leaf for all the genotypes.

Looking for a similar partner: host plants shape mating preferences of herbivorous insects by altering their contact pheromones.

PubMed

Geiselhardt, Sven; Otte, Tobias; Hilker, Monika

2012-09-01

The role of phenotypical plasticity in ecological speciation and the evolution of sexual isolation remains largely unknown. We investigated whether or not divergent host plant use in an herbivorous insect causes assortative mating by phenotypically altering traits involved in mate recognition. We found that males of the mustard leaf beetle Phaedon cochleariae preferred to mate with females that were reared on the same plant species to females provided with a different plant species, based on divergent cuticular hydrocarbon profiles that serve as contact pheromones. The cuticular hydrocarbon phenotypes of the beetles were host plant specific and changed within 2 weeks after a shift to a novel host plant species. We suggest that plant-induced phenotypic divergence in mate recognition cues may act as an early barrier to gene flow between herbivorous insect populations on alternative host species, preceding genetic divergence and thus, promoting ecological speciation. © 2012 Blackwell Publishing Ltd/CNRS.

Geographic variation in feeding preference of a generalist herbivore: the importance of seaweed chemical defenses.

PubMed

McCarty, Amanda T; Sotka, Erik E

2013-08-01

The ecological impacts of generalist herbivores depend on feeding preferences, which can vary across and within herbivore species. Among mesoherbivores, geographic variation in host use can occur because host plants have a more restricted geographic distribution than does the herbivore, or there is local evolution in host preference, or both. We tested the role of local evolution using the marine amphipod Ampithoe longimana by rearing multiple amphipod populations from three regions (subtropical Florida, warm-temperate North Carolina and cold-temperate New England) and assaying their feeding preferences toward ten seaweeds that occur in some but not all regions. Six of the ten seaweeds produce anti-herbivore secondary metabolites, and we detected geographic variation in feeding preference toward five (Dictyota menstrualis, Dictyota ciliolata, Fucus distichus, Chondrus crispus and Padina gymnospora, but not Caulerpa sertularioides). Amphipod populations that co-occur with a chemically-rich seaweed tended to have stronger feeding preferences for that seaweed, relative to populations that do not co-occur with the seaweed. A direct test indicated that geographic variation in feeding preference toward one seaweed (D. ciliolata) is mediated by feeding tolerance for lipophilic secondary metabolites. Among the four seaweeds that produce no known secondary metabolites (Acanthophora, Ectocarpus, Gracilaria and Hincksia/Feldmannia spp.), we detected no geographic variation in feeding preference. Thus, populations are more likely to evolve greater feeding preferences for local hosts when those hosts produce secondary metabolites. Microevolution of feeding behaviors of generalist marine consumers likely depends on the availability and identity of local hosts and the strength of their chemical defenses.

Brucella Genetic Variability in Wildlife Marine Mammals Populations Relates to Host Preference and Ocean Distribution.

PubMed

Suárez-Esquivel, Marcela; Baker, Kate S; Ruiz-Villalobos, Nazareth; Hernández-Mora, Gabriela; Barquero-Calvo, Elías; González-Barrientos, Rocío; Castillo-Zeledón, Amanda; Jiménez-Rojas, César; Chacón-Díaz, Carlos; Cloeckaert, Axel; Chaves-Olarte, Esteban; Thomson, Nicholas R; Moreno, Edgardo; Guzmán-Verri, Caterina

2017-07-01

Intracellular bacterial pathogens probably arose when their ancestor adapted from a free-living environment to an intracellular one, leading to clonal bacteria with smaller genomes and less sources of genetic plasticity. Still, this plasticity is needed to respond to the challenges posed by the host. Members of the Brucella genus are facultative-extracellular intracellular bacteria responsible for causing brucellosis in a variety of mammals. The various species keep different host preferences, virulence, and zoonotic potential despite having 97-99% similarity at genome level. Here, we describe elements of genetic variation in Brucella ceti isolated from wildlife dolphins inhabiting the Pacific Ocean and the Mediterranean Sea. Comparison with isolates obtained from marine mammals from the Atlantic Ocean and the broader Brucella genus showed distinctive traits according to oceanic distribution and preferred host. Marine mammal isolates display genetic variability, represented by an important number of IS711 elements as well as specific IS711 and SNPs genomic distribution clustering patterns. Extensive pseudogenization was found among isolates from marine mammals as compared with terrestrial ones, causing degradation in pathways related to energy, transport of metabolites, and regulation/transcription. Brucella ceti isolates infecting particularly dolphin hosts, showed further degradation of metabolite transport pathways as well as pathways related to cell wall/membrane/envelope biogenesis and motility. Thus, gene loss through pseudogenization is a source of genetic variation in Brucella, which in turn, relates to adaptation to different hosts. This is relevant to understand the natural history of bacterial diseases, their zoonotic potential, and the impact of human interventions such as domestication. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Undetected Infection by Maize Bushy Stunt Phytoplasma Enhances Host-Plant Preference to Dalbulus maidis (Hemiptera: Cicadellidae).

PubMed

García Gonzalez, Javier; Giraldo Jaramillo, Marisol; Roberto Spotti Lopes, João

2018-04-05

Vector-borne plant pathogenic bacteria can induce changes in infected plants favoring the insect vector behavior and biology. The study aimed to determine the effect of maize bushy stunt phytoplasma (MBSP) postinoculation period on the host plant preference and transmission efficiency by the corn leafhopper, Dalbulus maidis DeLong & Wolcott, 1923 (Hemiptera: Cicadellidae). In a series of choice tests, D. maidis preference was measured as settling and oviposition on healthy maize plants versus infected maize plants showing early disease symptoms, advanced symptoms, or no symptoms. Finally, transmission efficiency of D. maidis was measured when the vector previously acquired the phytoplasma from asymptomatic source plants at different postinoculation periods. D. maidis adults preferred to settle and to oviposit on healthy than on symptomatic infected plants with advanced disease symptoms, and preferred asymptomatic plants over symptomatic ones. MBSP transmission by D. maidis was positively correlated with the postinoculation period of the source plant. Results suggest an MBSP modulation for D. maidis preference on asymptomatic infected maize plants in the early stages of the crop, allowing the pathogen an undetected transmission.

Parasitic nematode Meloidogyne incognita interactions with different Capsicum annum cultivars reveal the chemical constituents modulating root herbiovry

USDA-ARS?s Scientific Manuscript database

Plant volatile signatures are often used as cues by herbivores to locate their preferred hosts. Here, we report on the volatile organic compounds used by the subterranean root-knot nematode (RKN) Meloidogyne incognita for host location. We compared responses of infective second stage juveniles (J2s)...

Fatty acid-producing hosts

DOEpatents

Pfleger, Brian F; Lennen, Rebecca M

2013-12-31

Described are hosts for overproducing a fatty acid product such as a fatty acid. The hosts include an exogenous nucleic acid encoding a thioesterase and, optionally, an exogenous nucleic acid encoding an acetyl-CoA carboxylase, wherein an acyl-CoA synthetase in the hosts are functionally delected. The hosts prefereably include the nucleic acid encoding the thioesterase at an intermediate copy number. The hosts are preferably recominantly stable and growth-competent at 37.degree. C. Methods of producing a fatty acid product comprising culturing such hosts at 37.degree. C. are also described.

Cockroach Oothecal Parasitoid, Evania appendigaster (Hymenoptera: Evaniidae) Exhibits Oviposition Preference Towards Oothecal Age Most Vulnerable to Host Cannibalism.

PubMed

Tee, Hui-Siang; Lee, Chow-Yang

2017-12-05

Many female parasitoid wasps optimize host selection to balance the benefits of high-quality hosts and the costs of predator- or hyperparasitoid-induced mortality risks to maximize their fitness. Cannibalism exists in many insect species and affects survival of parasitoid larvae developing in or on parasitized hosts. However, little is known about how parasitoid wasps resolve the fitness consequence of host cannibalism-induced mortality risk during host selection. We examined the effect of oothecal age on cannibalism in the American cockroach Periplaneta americana (L.) (Dictyoptera: Blattidae) and its effect on host age selection and fitness of its oothecal parasitoid Evania appendigaster (L.) (Hymenoptera: Evaniidae). P. americana differentially cannibalized 1-d-old (30‒60%) versus 10- to 40-d-old oothecae (<9%). However, parasitoid females did not avoid but still preferred to parasitize 1-d-old (45%) over 10- to 40-d-old oothecae (1.6‒20%). The parasitism rate was greater and the handling time was shorter on 1-d-old compared to older oothecae. For parasitoid progeny emerging from different-aged oothecae, regression analysis showed that development time increased and body size (measured as hind tibia length) and longevity decreased with oothecal age. These results demonstrate that reduced parasitoid progeny survival due to host cannibalism did not change the parasitoid's oviposition preference for newly laid oothecae, and that E. appendigaster females traded progeny survival for fitness gains for themselves and their progeny. © 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.

Why do horseflies need polarization vision for host detection? Polarization helps tabanid flies to select sunlit dark host animals from the dark patches of the visual environment

PubMed Central

Szörényi, Tamás; Pereszlényi, Ádám; Gerics, Balázs; Hegedüs, Ramón; Barta, András

2017-01-01

Horseflies (Tabanidae) are polarotactic, being attracted to linearly polarized light when searching for water or host animals. Although it is well known that horseflies prefer sunlit dark and strongly polarizing hosts, the reason for this preference is unknown. According to our hypothesis, horseflies use their polarization sensitivity to look for targets with higher degrees of polarization in their optical environment, which as a result facilitates detection of sunlit dark host animals. In this work, we tested this hypothesis. Using imaging polarimetry, we measured the reflection–polarization patterns of a dark host model and a living black cow under various illumination conditions and with different vegetation backgrounds. We focused on the intensity and degree of polarization of light originating from dark patches of vegetation and the dark model/cow. We compared the chances of successful host selection based on either intensity or degree of polarization of the target and the combination of these two parameters. We show that the use of polarization information considerably increases the effectiveness of visual detection of dark host animals even in front of sunny–shady–patchy vegetation. Differentiation between a weakly polarizing, shady (dark) vegetation region and a sunlit, highly polarizing dark host animal increases the efficiency of host search by horseflies. PMID:29291065

Why do horseflies need polarization vision for host detection? Polarization helps tabanid flies to select sunlit dark host animals from the dark patches of the visual environment.

PubMed

Horváth, Gábor; Szörényi, Tamás; Pereszlényi, Ádám; Gerics, Balázs; Hegedüs, Ramón; Barta, András; Åkesson, Susanne

2017-11-01

Horseflies (Tabanidae) are polarotactic, being attracted to linearly polarized light when searching for water or host animals. Although it is well known that horseflies prefer sunlit dark and strongly polarizing hosts, the reason for this preference is unknown. According to our hypothesis, horseflies use their polarization sensitivity to look for targets with higher degrees of polarization in their optical environment, which as a result facilitates detection of sunlit dark host animals. In this work, we tested this hypothesis. Using imaging polarimetry, we measured the reflection-polarization patterns of a dark host model and a living black cow under various illumination conditions and with different vegetation backgrounds. We focused on the intensity and degree of polarization of light originating from dark patches of vegetation and the dark model/cow. We compared the chances of successful host selection based on either intensity or degree of polarization of the target and the combination of these two parameters. We show that the use of polarization information considerably increases the effectiveness of visual detection of dark host animals even in front of sunny-shady-patchy vegetation. Differentiation between a weakly polarizing, shady (dark) vegetation region and a sunlit, highly polarizing dark host animal increases the efficiency of host search by horseflies.

Performances of survival, feeding behavior, and gene expression in aphids reveal their different fitness to host alteration

PubMed Central

Lu, Hong; Yang, Pengcheng; Xu, Yongyu; Luo, Lan; Zhu, Junjie; Cui, Na; Kang, Le; Cui, Feng

2016-01-01

Insect populations feeding on different plant species are under selection pressure to adapt to these differences. A study integrating elements of the ecology, behavior, and gene expression of aphids on different host plants has not yet been well-explored. The present study explores the relationship between host fitness and survival, feeding behavior, and salivary gland gene expression of a pea (Pisum sativum) host race of Acyrthosiphon pisum feeding on a common host Vicia faba and on three genetically-related hosts (Vicia villosa, Medicago truncatula, and Medicago sativa). Life table data indicated that aphids on non-favored hosts exhibited small size, low reproduction rate, slow population increase and individual development, and long lifespan. Electrical penetration graph results showed that the aphids spent significantly less time in passive ingestion of phloem sap on all non-preferred host plants before acclimation. After a period of acclimation on M. truncatula and V. villosa, pea host race individuals showed improved feeding behavior. No individuals of the pea host race completed its life history on M. sativa. Interestingly, the number of host-specific differentially-expressed salivary gland genes was negatively correlated with the fitness of aphids on this host plant. This study provided important cues in host plant specialization in aphids. PMID:26758247

The influence of climatic niche preferences on the population genetic structure of a mistletoe species complex.

PubMed

Ramírez-Barahona, Santiago; González, Clementina; González-Rodríguez, Antonio; Ornelas, Juan Francisco

2017-06-01

The prevalent view on genetic structuring in parasitic plants is that host-race formation is caused by varying degrees of host specificity. However, the relative importance of ecological niche divergence and host specificity to population differentiation remains poorly understood. We evaluated the factors associated with population differentiation in mistletoes of the Psittacanthus schiedeanus complex (Loranthaceae) in Mexico. We used genetic data from chloroplast sequences and nuclear microsatellites to study population genetic structure and tested its association with host preferences and climatic niche variables. Pairwise genetic differentiation was associated with environmental and host preferences, independent of geography. However, environmental predictors appeared to be more important than host preferences to explain genetic structure, supporting the hypothesis that the occurrence of the parasite is largely determined by its own climatic niche and, to a lesser degree, by host specificity. Genetic structure is significant within this mistletoe species complex, but the processes associated with this structure appear to be more complex than previously thought. Although host specificity was not supported as the major determinant of population differentiation, we consider this to be part of a more comprehensive ecological model of mistletoe host-race formation that incorporates the effects of climatic niche evolution. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Parasitic wasp females are attracted to blends of host-induced plant volatiles: do qualitative and quantitative differences in the blend matter?

PubMed Central

Uefune, Masayoshi; Kugimiya, Soichi; Ozawa, Rika; Takabayashi, Junji

2013-01-01

Naïve Cotesia vestalis wasps, parasitoids of diamondback moth (DBM) larvae, are attracted to a synthetic blend (Blend A) of host-induced plant volatiles composed of sabinene, n-heptanal, α-pinene, and ( Z)-3-hexenyl acetate, in a ratio of 1.8:1.3:2.0:3.0. We studied whether qualitative (adding ( R)-limonene: Blend B) or quantitative changes (changing ratios: Blend C) to Blend A affected the olfactory response of C. vestalis in the background of intact komatsuna plant volatiles. Naïve wasps showed equal preference to Blends A and B and Blends A and C in two-choice tests. Wasps with oviposition experience in the presence of Blend B preferred Blend B over Blend A, while wasps that had oviposited without a volatile blend showed no preference between the two. Likewise, wasps that had starvation experience in the presence of Blend B preferred Blend A over Blend B, while wasps that had starved without a volatile blend showed no preference between the two. Wasps that had oviposition experience either with or without Blend A showed equal preferences between Blends C and A. However, wasps that had starvation experience in the presence of Blend A preferred Blend C over Blend A, while those that starved without a volatile blend showed equal preferences between the two. By manipulating quality and quantity of the synthetic attractants, we showed to what extent C. vestalis could discriminate/learn slight differences between blends that were all, in principle, attractive. PMID:24358892

Does sex-biased dispersal account for the lack of geographic and host-associated differentiation in introduced populations of an aphid parasitoid?

PubMed Central

Zepeda-Paulo, Francisca; Lavandero, Blas; Mahéo, Frédérique; Dion, Emilie; Outreman, Yannick; Simon, Jean-Christophe; Figueroa, Christian C

2015-01-01

Host recognition and use in female parasitoids strongly relies on host fidelity, a plastic behavior which can significantly restrict the host preferences of parasitoids, thus reducing the gene flow between parasitoid populations attacking different insect hosts. However, the effect of migrant males on the genetic differentiation of populations has been frequently ignored in parasitoids, despite its known impact on gene flow between populations. Hence, we studied the extent of gene flow mediated by female and male parasitoids by assessing sibship relationships among parasitoids within and between populations, and its impact on geographic and host-associated differentiation in the aphid parasitoid Aphidius ervi. We report evidences of a high gene flow among parasitoid populations on different aphid hosts and geographic locations. The high gene flow among parasitoid populations was found to be largely male mediated, suggested by significant differences in the distribution of full-sib and paternal half-sib dyads of parasitoid populations. PMID:26078852

Different patterns of oviposition learning in two closely related ectoparasitoid wasps with contrasting reproductive strategies

NASA Astrophysics Data System (ADS)

Sasakawa, Kôji; Uchijima, Kenta; Shibao, Harunobu; Shimada, Masakazu

2013-02-01

Many parasitoid wasps learn host-associated cues and use them in subsequent host-searching behavior. This associative learning, namely "oviposition learning," has been investigated in many studies. However, few studies have compared multiple species, and no comparative study has previously been conducted on ectoparasitoid species. We compared the effects of oviposition learning on host preference and offspring sex ratio in two closely related ectoparasitoid wasps with contrasting reproductive strategies, Anisopteromalus calandrae (r-strategist) and its sibling species (K-strategist). Using two bruchine hosts, Callosobruchus chinensis and Callosobruchus maculatus larvae infesting the cowpea Vigna unguiculata, oviposition choice experiments were performed at high and low host densities. In both species, no conspicuous effect on the offspring sex ratio was detected, but effects on host preference were found to differ between the species. In A. calandrae, the effects were detected only at high host density, suggesting that oviposition learning plays a role in host discrimination from a short distance but not from a long distance. In the sibling species, those effects were not detected in any of the cases, suggesting the absence of oviposition learning. These results are compatible with those of previous comparative studies of endoparasitoid wasps in that few lifetime oviposition experiences and/or low reward per foraging decision result in low or absent oviposition learning ability. This finding may indicate that ecological traits contributing to learning ability are similar between endoparasitoid and ectoparasitoid wasps. Thus, our species comparison of ectoparasitoids provides another model system for investigating learning and memory dynamics in parasitoid wasps.

Premating isolation is determined by larval rearing substrates in cactophilic Drosophila mojavensis. IX. Host plant and population specific epicuticular hydrocarbon expression influences mate choice and sexual selection.

PubMed

Havens, J A; Etges, W J

2013-03-01

Sexual signals in cactophilic Drosophila mojavensis include cuticular hydrocarbons (CHCs), contact pheromones that mediate female discrimination of males during courtship. CHCs, along with male courtship songs, cause premating isolation between diverged populations, and are influenced by genotype × environment interactions caused by different host cacti. CHC profiles of mated and unmated adult flies from a Baja California and a mainland Mexico population of D. mojavensis reared on two host cacti were assayed to test the hypothesis that male CHCs mediate within-population female discrimination of males. In multiple choice courtship trials, mated and unmated males differed in CHC profiles, indicating that females prefer males with particular blends of CHCs. Mated and unmated females significantly differed in CHC profiles as well. Adults in the choice trials had CHC profiles that were significantly different from those in pair-mated adults from no-choice trials revealing an influence of sexual selection. Females preferred different male CHC blends in each population, but the influence of host cactus on CHC variation was significant only in the mainland population indicating population-specific plasticity in CHCs. Different groups of CHCs mediated female choice-based sexual selection in each population suggesting that geographical and ecological divergence has the potential to promote divergence in mate communication systems. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

Disentangling the visual cues used by a jumping spider to locate its microhabitat.

PubMed

Tedore, Cynthia; Johnsen, Sönke

2016-08-01

Many arthropod species have evolved to thrive only on the leaves of a particular species of plant, which they must be capable of finding in order to survive accidental displacement, developmental transitions or the changing of the seasons. A number of studies have tested whether such species select leaves to land or oviposit on based on their color, shape or size. Unfortunately, many studies did not control for correlates of these characters, such as the brightness of different colors, the areas of different shapes, and the level of ambient illumination in the vicinity of different sizes of leaves. In the present study, we tested for leaf color, shape and size preferences in a leaf-dwelling jumping spider (Lyssomanes viridis) with known summer and winter host plants, while controlling for these correlates. First, color preferences were tested outdoors under the natural illumination of their forest habitat. Lyssomanes viridis did not prefer to perch on a green substrate compared with various shades of gray, but did prefer the second darkest shade of gray we presented them with. Of the green and gray substrates, this shade of gray's integrated photon flux (350-700 nm), viewed from below, i.e. the spider's perspective in the arena, was the most similar to that of real leaves. This relationship also held when we weighted the transmitted photon flux by the jumping spiders' green photopigment spectral sensitivity. Spiders did not prefer the star-like leaf shape of their summer host plant, Liquidambar styraciflua, to a green circle of the same area. When given a choice between a L. styraciflua leaf-shaped stimulus that was half the area of an otherwise identical alternative, spiders preferred the larger stimulus. However, placing a neutral density filter over the side of the experimental arena with the smaller stimulus abolished this preference, with spiders then being more likely to choose the side of the arena with the smaller stimulus. In conclusion, L. viridis appears to use ambient illumination and possibly perceived leaf brightness but not leaf shape or color to locate its microhabitat. This calls for a careful re-examination of which visual cues a variety of arthropods are actually attending to when they search for their preferred host species or microhabitat. © 2016. Published by The Company of Biologists Ltd.

Low offspring survival in mountain pine beetle infesting the resistant Great Basin bristlecone pine supports the preference-performance hypothesis.

PubMed

Eidson, Erika L; Mock, Karen E; Bentz, Barbara J

2018-01-01

The preference-performance hypothesis states that ovipositing phytophagous insects will select host plants that are well-suited for their offspring and avoid host plants that do not support offspring performance (survival, development and fitness). The mountain pine beetle (Dendroctonus ponderosae), a native insect herbivore in western North America, can successfully attack and reproduce in most species of Pinus throughout its native range. However, mountain pine beetles avoid attacking Great Basin bristlecone pine (Pinus longaeva), despite recent climate-driven increases in mountain pine beetle populations at the high elevations where Great Basin bristlecone pine grows. Low preference for a potential host plant species may not persist if the plant supports favorable insect offspring performance, and Great Basin bristlecone pine suitability for mountain pine beetle offspring performance is unclear. We infested cut bolts of Great Basin bristlecone pine and two susceptible host tree species, limber (P. flexilis) and lodgepole (P. contorta) pines with adult mountain pine beetles and compared offspring performance. To investigate the potential for variation in offspring performance among mountain pine beetles from different areas, we tested beetles from geographically-separated populations within and outside the current range of Great Basin bristlecone pine. Although mountain pine beetles constructed galleries and laid viable eggs in all three tree species, extremely few offspring emerged from Great Basin bristlecone pine, regardless of the beetle population. Our observed low offspring performance in Great Basin bristlecone pine corresponds with previously documented low mountain pine beetle attack preference. A low preference-low performance relationship suggests that Great Basin bristlecone pine resistance to mountain pine beetle is likely to be retained through climate-driven high-elevation mountain pine beetle outbreaks.

Low offspring survival in mountain pine beetle infesting the resistant Great Basin bristlecone pine supports the preference-performance hypothesis

PubMed Central

Mock, Karen E.; Bentz, Barbara J.

2018-01-01

The preference-performance hypothesis states that ovipositing phytophagous insects will select host plants that are well-suited for their offspring and avoid host plants that do not support offspring performance (survival, development and fitness). The mountain pine beetle (Dendroctonus ponderosae), a native insect herbivore in western North America, can successfully attack and reproduce in most species of Pinus throughout its native range. However, mountain pine beetles avoid attacking Great Basin bristlecone pine (Pinus longaeva), despite recent climate-driven increases in mountain pine beetle populations at the high elevations where Great Basin bristlecone pine grows. Low preference for a potential host plant species may not persist if the plant supports favorable insect offspring performance, and Great Basin bristlecone pine suitability for mountain pine beetle offspring performance is unclear. We infested cut bolts of Great Basin bristlecone pine and two susceptible host tree species, limber (P. flexilis) and lodgepole (P. contorta) pines with adult mountain pine beetles and compared offspring performance. To investigate the potential for variation in offspring performance among mountain pine beetles from different areas, we tested beetles from geographically-separated populations within and outside the current range of Great Basin bristlecone pine. Although mountain pine beetles constructed galleries and laid viable eggs in all three tree species, extremely few offspring emerged from Great Basin bristlecone pine, regardless of the beetle population. Our observed low offspring performance in Great Basin bristlecone pine corresponds with previously documented low mountain pine beetle attack preference. A low preference-low performance relationship suggests that Great Basin bristlecone pine resistance to mountain pine beetle is likely to be retained through climate-driven high-elevation mountain pine beetle outbreaks. PMID:29715269

Habitat preference and the evolution of sympatric intersterility groups in the Heterbasidion annosum species complex

Treesearch

M. Garbelotto; W.J. Otrosina; F.W. Cobb; T.D. Bruns

1998-01-01

Populations of the basidiomycete Heterobasidion annosum display varying degrees, of intersterility and differential host specialization. At least three intersterility groups have been formally described, each characterized by a range of "preferred" hosts. It has been hypothesized that processes of host-pathogen compatibility may have been...

Host plant, temperature, and photoperiod effects on ovipositional preference of Frankliniella occidentalis and Frankliniella fusca (Thysanoptera: Thripidae).

PubMed

Chaisuekul, C; Riley, D G

2005-12-01

Host plant effects of tomato, Lycopersicon esculentum Mill., and chickweed, Stellaria media (L.) Vill., foliage infected and uninfected with Tomato spotted wilt virus (family Bunyaviridae, genus Tospovirus, TSWV) on the ovipositional preferences of western flower thrips, Frankliniella occidentalis (Pergande), and tobacco thrips, Frankliniella fusca (Hinds), were investigated for whole plants in the greenhouse. In addition, the preference for leaf disks from the same host plants was investigated under a range of temperatures, 15-30 degrees C at a photoperiod of 12:12 (L:D) h, and at three photoperiods, 6:18, 12:12, and 18:6, at 20 degrees C in no-choice and choice studies conducted in growth chambers. In a choice test, F. fusca oviposited significantly more eggs per whole plant foliage over a 7-d period than F. occidentalis by an average ratio of 3:1 over both tomato and chickweed. The optimum temperature for oviposition of F. occidentalis and F. fusca was 24.5 and 24.9 degrees C, respectively. Both species laid significantly more eggs under the longest daylight hours tested, 18:6, in the choice study. Temperature and photoperiod did not significantly interact in terms of thrips ovipositional preference. Ovipositional preference for chickweed or tomato foliage was different for each thrips species in the choice and no-choice tests. However, both thrips species laid significantly more eggs per square centimeter of leaf area in chickweed than in tomato in the whole plant choice test.

Brucella

USDA-ARS?s Scientific Manuscript database

The genus Brucella encompasses a group of gram negative bacteria that survive almost exclusively in infected hosts with preference for localization in intracellular compartments of cells. The genus has traditionally been divided into species based on microbe characteristics and host preference, bu...

Brucella

USDA-ARS?s Scientific Manuscript database

Brucella are intracellular pathogens that cause reproductive losses in animals and zoonotic infections in people. Although named by preferred host species, members of the Brucella genus are capable of infecting multiple species. In preferred hosts, clinical symptoms are generally minimal whereas m...

Relationship of host recurrence in fungi to rates of tropical leaf decomposition

Treesearch

Mirna E. Santanaa; JeanD. Lodgeb; Patricia Lebowc

2004-01-01

Here we explore the significance of fungal diversity on ecosystem processes by testing whether microfungal ‘preferences’ for (i.e., host recurrence) different tropical leaf species increases the rate of decomposition. We used pairwise combinations of girradiated litter of five tree species with cultures of two dominant microfungi derived from each plant in a microcosm...

Relationship of host recurrence in fungi to rates of tropical leaf decomposition

Treesearch

Mirna E. Santana; D. Jean Lodge; Patricia Lebow

2005-01-01

Here we explore the significance of fungal diversity on ecosystem processes by testing whether microfungal ‘preferences’ for (i.e., host recurrence) different tropical leaf species increases the rate of decomposition. We used pairwise combinations of [gamma]-irradiated litter of five tree species with cultures of two dominant microfungi derived from each plant in a...

Experience-induced habituation and preference towards non-host plant odors in ovipositing females of a moth.

PubMed

Wang, Hua; Guo, Wen-Fei; Zhang, Peng-Jun; Wu, Zhi-Yi; Liu, Shu-Sheng

2008-03-01

In phytophagous insects, experience can increase positive responses towards non-host plant extracts or induce oviposition on non-host plants, but the underlying chemical and behavioral mechanisms are poorly understood. By using the diamondback moth, Plutella xylostella, its host plant Chinese cabbage, and a non-host plant Chrysanthemum morifolium, as a model system, we observed the experience-altered olfactory responses of ovipositing females towards volatiles of the non-host plant, volatiles of pure chemicals (p-cymene and alpha-terpinene) found in the non-host plant, and volatiles of host plants treated with these chemicals. We assessed the experience-altered oviposition preference towards host plants treated with p-cymene. Naive females showed aversion to the odors of the non-host plant, the pure chemicals, and the pure chemical-treated host plants. In contrast, experienced females either became attracted by these non-host odors or were no longer repelled by these odors. Similarly, naive females laid a significantly lower proportion of eggs on pure chemical-treated host plants than on untreated host plants, but experienced females laid a similar or higher proportion of eggs on pure chemical-treated host plants compared to untreated host plants. Chemical analysis indicated that application of the non-host pure chemicals on Chinese cabbage induced emissions of volatiles by this host plant. We conclude that induced preference for previously repellent compounds is a major mechanism that leads to behavioral changes of this moth towards non-host plants or their extracts.

Genome-wide analysis of codon usage bias in Ebolavirus.

PubMed

Cristina, Juan; Moreno, Pilar; Moratorio, Gonzalo; Musto, Héctor

2015-01-22

Ebola virus (EBOV) is a member of the family Filoviridae and its genome consists of a 19-kb, single-stranded, negative sense RNA. EBOV is subdivided into five distinct species with different pathogenicities, being Zaire ebolavirus (ZEBOV) the most lethal species. The interplay of codon usage among viruses and their hosts is expected to affect overall viral survival, fitness, evasion from host's immune system and evolution. In the present study, we performed comprehensive analyses of codon usage and composition of ZEBOV. Effective number of codons (ENC) indicates that the overall codon usage among ZEBOV strains is slightly biased. Different codon preferences in ZEBOV genes in relation to codon usage of human genes were found. Highly preferred codons are all A-ending triplets, which strongly suggests that mutational bias is a main force shaping codon usage in ZEBOV. Dinucleotide composition also plays a role in the overall pattern of ZEBOV codon usage. ZEBOV does not seem to use the most abundant tRNAs present in the human cells for most of their preferred codons. Copyright © 2014 Elsevier B.V. All rights reserved.

Method for gas bubble and void control and removal from metals

DOEpatents

Van Siclen, Clinton D.; Wright, Richard N.

1996-01-01

A method for enhancing the diffusion of gas bubbles or voids attached to impurity precipitates, and biasing their direction of migration out of the host metal (or metal alloy) by applying a temperature gradient across the host metal (or metal alloy). In the preferred embodiment of the present invention, the impurity metal is insoluble in the host metal and has a melting point lower than the melting point of the host material. Also, preferably the impurity metal is lead or indium and the host metal is aluminum or a metal alloy.

Genetics of host plant use and life history in the comma butterfly across Europe: varying modes of inheritance as a potential reproductive barrier.

PubMed

Nygren, G H; Nylin, S; Stefanescu, C

2006-11-01

Comma butterflies (Nymphalidae: Polygonia c-album L.) from one Belgian site and three Spanish sites were crossed with butterflies from a Swedish population in order to investigate inheritance of female host plant choice, egg mass and larval growth rate. We found three different modes of inheritance for the three investigated traits. In line with earlier results from crosses between Swedish and English populations, the results regarding female oviposition preference (choice between Urtica dioica and Salix caprea) showed X-linked inheritance to be of importance for the variation between Sweden and the other sites. Egg mass and growth rate did not show any sex-linked inheritance. Egg mass differences between populations seem to be controlled mainly by additive autosomal genes, as hybrids showed intermediate values. The growth rates of both hybrid types following reciprocal crossings were similar to each other but consistently higher than for the two source populations, suggesting a nonadditive mode of inheritance which is not sex-linked. The different modes of inheritance for host plant preference vs. important life history traits are likely to result in hybrids with unfit combinations of traits. This type of potential reproductive barrier based on multiple ecologically important traits deserves more attention, as it should be a common situation for instance in the early stages of population divergence in host plant usage, facilitating ecological speciation.

Leaf Quality and the Host Preferences of Gypsy Moth in the Northern Deciduous Forest

Treesearch

Martin J.  Lechowicz

1983-01-01

Both gypsy morh host preferences and the foliage characteristics thaL have been implicated as factors in host selection were monitored from 1979 to 1982 in a Quercus-Acer-Ostrya forest near Montreal, Quebec. The preliminary analyses of these data suggest the hypothesis that gypsy moth larvae preferentially attack trees that have high sugar:tannin...

Echinostoma trivolvis (Digenea: Echinostomatidae) second intermediate host preference matches host suitability.

PubMed

Wojdak, Jeremy M; Clay, Letitia; Moore, Sadé; Williams, Taylore; Belden, Lisa K

2013-02-01

Many trematodes infect a single mollusk species as their first intermediate host, and then infect a variety of second intermediate host species. Determining the factors that shape host specificity is an important step towards understanding trematode infection dynamics. Toward this end, we studied two pond snails (Physa gyrina and Helisoma trivolvis) that can be infected as second intermediate hosts by the trematode Echinostoma trivolvis lineage a (ETa). We performed laboratory preference trials with ETa cercariae in the presence of both snail species and also characterized host suitability by quantifying encystment and excystment success for each host species alone. We tested the prediction that trematodes might preferentially infect species other than their obligate first intermediate host (in this case, H. trivolvis) as second intermediate hosts to avoid potentially greater host mortality associated with residing in first intermediate hosts. In our experiments, ETa had roughly equivalent encystment success in Helisoma and Physa snails, but greater excystment success in Physa, when offered each species in isolation. Also, the presence of the symbiotic oligochaete Chaetogaster limnaei in a subset of Helisoma snails reduced encystment success in those individuals. When both hosts were present, we found dramatically reduced infection prevalence and intensity in Helisoma-ETa cercariae strongly preferred Physa. Thus, the presence of either an alternative host, or a predator of free-living parasites, offered protection for Helisoma snails from E. trivolvis lineage a infection.

Host Range and Selectivity of the Hemiparasitic Plant Thesium chinense (Santalaceae)

PubMed Central

Suetsugu, Kenji; Kawakita, Atsushi; Kato, Makoto

2008-01-01

Background and Aims Thesium chinense is a hemiparasitic plant that is common in grassland habitats of eastern Asia. Although the physiology of Thesium has been well studied in attempts to control its weedy habit, there have been few ecological investigations of its parasitic life history. Thesium chinense is thought to parasitize species of Poaceae, but evidence remains circumstantial. Methods A vegetation survey was conducted to test whether any plant species occurs significantly more often in plots with T. chinense than expected. In addition, haustorial connections were examined directly by excavating the roots and post-attachment host selectivity was evaluated by comparing the observed numbers of haustoria on different hosts against those expected according to the relative below-ground biomass. Haustorium sizes were also compared among host species. Key Results Only two of the 38 species recorded, Lespedeza juncea and Eragrostis curvula, occurred more often in plots with Thesium than expected. In contrast to this, T. chinense parasitized 22 plant species in 11 families, corresponding to 57·9 % of plant species found at the study site. Haustoria were non-randomly distributed among host species, suggesting that there is some post-attachment host selectivity. Thesium chinense generally preferred the Poaceae, although haustoria formed on the Fabaceae were larger than those on other hosts. Conclusions This is the first quantitative investigation of the host range and selectivity of hemiparasitic plants of the Santalales. The preference for Fabaceae as hosts may be linked to the greater nutrient availability in these nitrogen-fixing plants. PMID:18492736

Adaptability of mitosporic stage in Sphaerodes mycoparasitica towards its mycoparasitic-polyphagous lifestyle.

PubMed

Vujanovic, Vladimir; Kim, Seon Hwa

2017-01-01

Sphaerodes mycoparasitica Vuj. is a Fusarium-specific mycoparasite. Some recent discoveries recognize its biotrophic polyphagous lifestyle as an interesting biocontrol property against a broad spectrum of mycotoxigenic Fusarium hosts. Secondary metabolites such as mycotoxins produced by Fusarium spp. may play an important role in the signaling process, allowing an early mycoparasite-host recognition. A multiple-paper-disc assay has been conducted to test S. mycoparasitica hyphal adaptability to filtrates of 12 Fusarium spp. This study shows that shifts of adapted and nonadapted hyphal migration towards different Fusarium-host filtrates may partly explain S. mycoparasitica polyphagous lifestyle, and its adaptability depending on host preference or compatibility. In terms of host compatibility, the current findings suggest that S. mycoparasitica tends to prefer native Fusarium hosts more related to its origin and propose that the mycoparasite could possess diphasic interactions such as biotrophic-attraction and antagonistic-inhibition relationships based on relative radial growth. This implies that the mycoparasite may use a group of mycotoxins produced by specific Fusarium spp. as an adaptive selective mechanism that facilitates a parasite-host recognition and further successful mycoparasitism. In particular, relative polarity or hydrophilicity/hydrophobicity of mycotoxins may be related to solubility and absorption properties in hyphae of the mycoparasite. Taken together, the studies of host compatibility and adaptability depending on host filtrates will aid in understanding complex mechanisms of S. mycoparasitica, as a promising model organism for a specific biotrophic mycoparasite to enhance and improve biocontrol efficacy against Fusaria.

Differential Colonization Dynamics of Cucurbit Hosts by Erwinia tracheiphila.

PubMed

Vrisman, Cláudio M; Deblais, Loïc; Rajashekara, Gireesh; Miller, Sally A

2016-07-01

Bacterial wilt is one of the most destructive diseases of cucurbits in the Midwestern and Northeastern United States. Although the disease has been studied since 1900, host colonization dynamics remain unclear. Cucumis- and Cucurbita-derived strains exhibit host preference for the cucurbit genus from which they were isolated. We constructed a bioluminescent strain of Erwinia tracheiphila (TedCu10-BL#9) and colonization of different cucurbit hosts was monitored. At the second-true-leaf stage, Cucumis melo plants were inoculated with TedCu10-BL#9 via wounded leaves, stems, and roots. Daily monitoring of colonization showed bioluminescent bacteria in the inoculated leaf and petiole beginning 1 day postinoculation (DPI). The bacteria spread to roots via the stem by 2 DPI, reached the plant extremities 4 DPI, and the plant wilted 6 DPI. However, Cucurbita plants inoculated with TedCu10-BL#9 did not wilt, even at 35 DPI. Bioluminescent bacteria were detected 6 DPI in the main stem of squash and pumpkin plants, which harbored approximately 10(4) and 10(1) CFU/g, respectively, of TedCu10-BL#9 without symptoms. Although significantly less systemic plant colonization was observed in nonpreferred host Cucurbita plants compared with preferred hosts, the mechanism of tolerance of Cucurbita plants to E. tracheiphila strains from Cucumis remains unknown.

orco mutant mosquitoes lose strong preference for humans and are not repelled by volatile DEET.

PubMed

DeGennaro, Matthew; McBride, Carolyn S; Seeholzer, Laura; Nakagawa, Takao; Dennis, Emily J; Goldman, Chloe; Jasinskiene, Nijole; James, Anthony A; Vosshall, Leslie B

2013-06-27

Female mosquitoes of some species are generalists and will blood-feed on a variety of vertebrate hosts, whereas others display marked host preference. Anopheles gambiae and Aedes aegypti have evolved a strong preference for humans, making them dangerously efficient vectors of malaria and Dengue haemorrhagic fever. Specific host odours probably drive this strong preference because other attractive cues, including body heat and exhaled carbon dioxide (CO2), are common to all warm-blooded hosts. Insects sense odours via several chemosensory receptor families, including the odorant receptors (ORs), membrane proteins that form heteromeric odour-gated ion channels comprising a variable ligand-selective subunit and an obligate co-receptor called Orco (ref. 6). Here we use zinc-finger nucleases to generate targeted mutations in the orco gene of A. aegypti to examine the contribution of Orco and the odorant receptor pathway to mosquito host selection and sensitivity to the insect repellent DEET (N,N-diethyl-meta-toluamide). orco mutant olfactory sensory neurons have greatly reduced spontaneous activity and lack odour-evoked responses. Behaviourally, orco mutant mosquitoes have severely reduced attraction to honey, an odour cue related to floral nectar, and do not respond to human scent in the absence of CO2. However, in the presence of CO2, female orco mutant mosquitoes retain strong attraction to both human and animal hosts, but no longer strongly prefer humans. orco mutant females are attracted to human hosts even in the presence of DEET, but are repelled upon contact, indicating that olfactory- and contact-mediated effects of DEET are mechanistically distinct. We conclude that the odorant receptor pathway is crucial for an anthropophilic vector mosquito to discriminate human from non-human hosts and to be effectively repelled by volatile DEET.

Lack of preference for infective faeces in Hymenolepis diminuta-infected beetles (Tenebrio molitor).

PubMed

Shea, John F

2007-09-01

The beetle-tapeworm life cycle provides a convenient system to study how host behaviour influences the probability of re-infection because initial and secondary infections can be tracked. The beetle, Tenebrio molitor, is infected with the tapeworm Hymenolepis diminuta when it ingests rat faeces containing tapeworm eggs, which upon hatching undergo five morphologically distinct stages while developing inside the beetle. In a series of preference trials, both individual and groups of previously infected beetles were exposed to baits of infective (faeces with eggs) and uninfective faeces. Beetles did not differ in the amount of time spent or in the number of occurrences at each bait type, suggesting that infected beetles show no preference for infective faeces. This may be a host adaptation to avoid further infection, parasite manipulation to avoid competition for host resources, or both. Further, once infected, beetles are no more or no less likely to become re-infected than uninfected beetles. An analysis of the mean and variance of infection suggests that some individuals are highly susceptible to and some are highly resistant to infection, with males being more variable than females. This could explain the higher load of cysticercoids observed in males.

Do flower color and floral scent of silene species affect host preference of Hadena bicruris, a seed-eating pollinator, under field conditions?

PubMed

Page, Paul; Favre, Adrien; Schiestl, Florian P; Karrenberg, Sophie

2014-01-01

Specialization in plant-insect interactions is an important driver of evolutionary divergence; yet, plant traits mediating such interactions are poorly understood. In this study, we investigated how flower color and floral scent are related to seed predation by a seed-eating pollinator. We used field-transplanted recombinant F2 hybrids between Silene latifolia and S. dioica that are the preferred and alternative hosts of the moth Hadena bicruris and crosses within these species for comparison. We scored seed predation and flower color and analyzed floral scent. Pinker S. dioica-like flowers and emission of α-pinene decreased the odds of seed predation while emission of benzyl acetate and 6-methyl-5-hepten-2-one increased the odds of seed predation. Emission of these compounds did not differ significantly between the two Silene species. Our results suggest that flower color plays an important role in the specific interaction of H. bicruris with its preferred host S. latifolia. The compounds α-pinene, benzyl acetate and 6-methyl-5-hepten-2-one could represent non-specific deterrents and attractants to ovipositing moths. Alternatively, emission of these compounds could be related to herbivory or pathogen attack and act as a signal for host quality. This would weaken the predictability of the plant's costs and benefits of the interaction and act to maintain an imperfect degree of specialization.

Do Flower Color and Floral Scent of Silene Species affect Host Preference of Hadena bicruris, a Seed-Eating Pollinator, under Field Conditions?

PubMed Central

Page, Paul; Favre, Adrien; Schiestl, Florian P.; Karrenberg, Sophie

2014-01-01

Specialization in plant–insect interactions is an important driver of evolutionary divergence; yet, plant traits mediating such interactions are poorly understood. In this study, we investigated how flower color and floral scent are related to seed predation by a seed-eating pollinator. We used field-transplanted recombinant F2 hybrids between Silene latifolia and S. dioica that are the preferred and alternative hosts of the moth Hadena bicruris and crosses within these species for comparison. We scored seed predation and flower color and analyzed floral scent. Pinker S. dioica-like flowers and emission of α-pinene decreased the odds of seed predation while emission of benzyl acetate and 6-methyl-5-hepten-2-one increased the odds of seed predation. Emission of these compounds did not differ significantly between the two Silene species. Our results suggest that flower color plays an important role in the specific interaction of H. bicruris with its preferred host S. latifolia. The compounds α-pinene, benzyl acetate and 6-methyl-5-hepten-2-one could represent non-specific deterrents and attractants to ovipositing moths. Alternatively, emission of these compounds could be related to herbivory or pathogen attack and act as a signal for host quality. This would weaken the predictability of the plant's costs and benefits of the interaction and act to maintain an imperfect degree of specialization. PMID:24905986

Metabolite exchange between microbiome members produces compounds that influence Drosophila behavior

PubMed Central

Fischer, Caleb N; Trautman, Eric P; Crawford, Jason M; Stabb, Eric V; Handelsman, Jo; Broderick, Nichole A

2017-01-01

Animals host multi-species microbial communities (microbiomes) whose properties may result from inter-species interactions; however, current understanding of host-microbiome interactions derives mostly from studies in which elucidation of microbe-microbe interactions is difficult. In exploring how Drosophila melanogaster acquires its microbiome, we found that a microbial community influences Drosophila olfactory and egg-laying behaviors differently than individual members. Drosophila prefers a Saccharomyces-Acetobacter co-culture to the same microorganisms grown individually and then mixed, a response mainly due to the conserved olfactory receptor, Or42b. Acetobacter metabolism of Saccharomyces-derived ethanol was necessary, and acetate and its metabolic derivatives were sufficient, for co-culture preference. Preference correlated with three emergent co-culture properties: ethanol catabolism, a distinct volatile profile, and yeast population decline. Egg-laying preference provided a context-dependent fitness benefit to larvae. We describe a molecular mechanism by which a microbial community affects animal behavior. Our results support a model whereby emergent metabolites signal a beneficial multispecies microbiome. DOI: http://dx.doi.org/10.7554/eLife.18855.001 PMID:28068220

Parasite Removal, but Not Herbivory, Deters Future Parasite Attachment on Tomato

PubMed Central

Tjiurutue, Muvari Connie; Palmer-Young, Evan C.; Adler, Lynn S.

2016-01-01

Plants face many antagonistic interactions that occur sequentially. Often, plants employ defense strategies in response to the initial damage that are highly specific and can affect interactions with subsequent antagonists. In addition to herbivores and pathogens, plants face attacks by parasitic plants, but we know little about how prior herbivory compared to prior parasite attachment affects subsequent host interactions. If host plants can respond adaptively to these different damage types, we predict that prior parasitism would have a greater deterrent effect on subsequent parasites than would prior herbivory. To test the effects of prior parasitism and prior herbivory on subsequent parasitic dodder (Cuscuta spp.) preference, we conducted two separate greenhouse studies with tomato hosts (Solanum lycopersicum). In the first experiment, we tested the effects of previous dodder attachment on subsequent dodder preference on tomato hosts using three treatments: control plants that had no previous dodder attachment; dodder-removed plants that had an initial dodder seedling attached, removed and left in the same pot to simulate parasite death; and dodder-continuous plants with an initial dodder seedling that remained attached. In the second experiment, we tested the effects of previous caterpillar damage (Spodoptera exigua) and mechanical damage on future dodder attachment on tomato hosts. Dodder attached most slowly to tomato hosts that had dodder plants previously attached and then removed, compared to control plants or plants with continuous dodder attachment. In contrast, herbivory did not affect subsequent dodder attachment rate. These results indicate that dodder preference depended on the identity and the outcome of the initial attack, suggesting that early-season interactions have the potential for profound impacts on subsequent community dynamics. PMID:27529694

Host Preferences of Gypsy Moth on a New Frontier of Infestation

Treesearch

David A. Gansner; Owen W. Herrick; Owen W. Herrick

1985-01-01

Knowing what gypsy moth likes to eat can aid forest managers in making cost-effective control decisions. A recent 5-year study of defoliation in central Pennsylvania gives an up-to-date index of host species preferences. Chestnut oak is the most preferred species. Following in relatively close order are the other oaks and aspen. Hardwood species that rank low on the...

Pasteuria spp.: Systematics and Phylogeny of These Bacterial Parasites of Phytopathogenic Nematodes.

PubMed

Preston, J F; Dickson, D W; Maruniak, J E; Nong, G; Brito, J A; Schmidt, L M; Giblin-Davis, R M

2003-06-01

Pasteuria spp. include endospore-forming bacterial pathogens of cladoceran crustaceans and plant-parasitic nematodes. Propagation of these nematode pathogens requires attachment of soilborne endospores to nematode hosts, infection, growth, sporulation, and release of endospores to repeat the cycle of infection and propagation. The ability of these bacteria to suppress the levels of plant-parasitic nematodes in the field has made them particularly promising candidates for biocontrol of nematode diseases of plants. Genes encoding 16S ribosomal RNA have been sequenced for the cladoceran (water flea) parasite and type species, Pasteuria ramosa, and for Pasteuria spp. isolated from root-knot (Meloidogyne arenaria race 1 and Meloidogyne sp.), soybean cyst (Heterodera glycines), and sting (Belonolaimus longicaudatus) nematodes. These have provided a phylogenetic basis for their designation to a distinct clade within the family Alicyclobacillaceae of the gram-positive endospore-forming bacteria. Two apparent biotypes of P. penetrans demonstrating a host preference for different Meloidogyne spp. showed identical 16S rDNA sequences, suggesting host-recognition evolves within a given species. The sequences of genes encoding sporulation transcription factors, sigE and sigF, from P. penetrans biotype P-20 show different phylogenetic relationships to other endospore-forming bacteria, supporting their application to further discriminate Pasteuria spp. and biotypes. Distribution of an adhesin-associated epitope on polypeptides from different Pasteuria isolates provides an immunochemical approach to differentiate species and biotypes with specific host preferences. Application of bioinformatics to genomic data, as well as further characterization of the biochemical basis for host recognition, will facilitate development of Pasteuria spp. as benign alternatives to chemical nematicides.

Method for gas bubble and void control and removal from metals

DOEpatents

Siclen, C.D. Van; Wright, R.N.

1996-02-06

A method is described for enhancing the diffusion of gas bubbles or voids attached to impurity precipitates, and biasing their direction of migration out of the host metal (or metal alloy) by applying a temperature gradient across the host metal (or metal alloy). In the preferred embodiment of the present invention, the impurity metal is insoluble in the host metal and has a melting point lower than the melting point of the host material. Also, preferably the impurity metal is lead or indium and the host metal is aluminum or a metal alloy. 2 figs.

Early-Season Host Switching in Adelphocoris spp. (Hemiptera: Miridae) of Differing Host Breadth

PubMed Central

Pan, Hongsheng; Lu, Yanhui; Wyckhuys, Kris A. G.

2013-01-01

The mirid bugs Adelphocoris suturalis (Jakovlev), Adelphocoris lineolatus (Goeze) and Adelphocoris fasciaticollis (Reuter) (Hemiptera: Miridae) are common pests of several agricultural crops. These three species have vastly different geographical distributions, phenologies and abundances, all of which are linked to their reliance on local plants. Previous work has shown notable differences in Adelphocoris spp. host use for overwintering. In this study, we assessed the extent to which each of the Adelphocoris spp. relies on some of its major overwinter hosts for spring development. Over the course of four consecutive years (2009–2012), we conducted population surveys on 77 different plant species from 39 families. During the spring, A. fasciaticollis used the broadest range of hosts, as it was found on 35 plant species, followed by A. suturalis (15 species) and A. lineolatus (7 species). Abundances of the species greatly differed between host plants, with A. fasciaticollis reaching the highest abundance on Chinese date (Ziziphus jujuba Mill.), whereas both A. suturalis and A. lineolatus preferred alfalfa (Medicago sativa L.). The host breadths of the three Adelphocoris spp. differed greatly between subsequent spring and winter seasons. The generalist species exhibited the least host fidelity, with A. suturalis and A. lineolatus using 8 of 22 and 4 of 12 overwinter host species for spring development, respectively. By contrast, the comparative specialist A. fasciaticollis relied on 9 of its 11 overwinter plants as early-season hosts. We highlight important seasonal changes in host breadth and interspecific differences in the extent of host switching behavior between the winter and spring seasons. These findings benefit our understanding of the evolutionary interactions between mirid bugs and their host plants and can be used to guide early-season population management. PMID:23527069

Host specificity of Argulus coregoni (Crustacea: Branchiura) increases at maturation.

PubMed

Mikheev, V N; Pasternak, A F; Valtonen, E T

2007-11-01

We tested the hypothesis that host specificity in ectoparasites does not depend exclusively on the features of the host but also on surrounding habitats, using 2 fish ectoparasites, Argulus coregoni and A. foliaceus (Crustacea: Branchiura), occurring sympatrically in Finnish lakes. Although these parasites are considered to be of low specificity, we found that the larger of the 2 species, A. coregoni developed a pronounced preference for salmonid hosts at the beginning of maturation (defined by the presence of copulating specimens). Argulus foliaceus infects a much wider range of fish hosts. We showed that specialization of A. coregoni on salmonids does not necessarily result from incompatibility with other fishes, but could instead reflect higher sensitivity of oxygen depletion compared with A. foliaceus. Adult A. coregoni may meet these demands by attaching to salmonids, the typical inhabitants of well-aerated waters. Young parasites of both species showed little host specificity and attached mainly to fishes with higher body reflectivity. In host choice experiments, A. coregoni of 4-5 mm length preferred salmonids (rainbow trout) to cyprinids (roach) irrespective of the type of fish host, on which it had been previously grown in the laboratory. We suggest that such an innate ontogenetic shift in host preference maintains the major part of the parasite population on its principal host, ensuring successful reproduction within suitable habitats.

Dynamics of glucosinolate-myrosinase system during Plutella xylostella interaction to a novel host Lepidium latifolium L.

PubMed

Kaur, Tarandeep; Bhat, Rohini; Khajuria, Manu; Vyas, Ruchika; Kumari, Anika; Nadda, Gireesh; Vishwakarma, Ram; Vyas, Dhiraj

2016-09-01

Plutella xylostella L. is a notorious pest of cruciferous crops causing worldwide losses of $4-5 billion per year. Developing classical biological control to this pest include an introduction of host plants that act as natural enemies showing deviation from the preference-performance regimen in the evolutionary ecology of plant-insect interactions. The present study was designed to understand the role of glucosinolate-myrosinase system during P. xylostella interactions with a novel host. Adult moth preference and larval performance study were conducted on a novel host Lepidium latifolium L. (LL) that has high sinigrin content and was compared with its laboratory host Arabidopsis thaliana (AT). The glucosinolate-myrosinase system was studied in a time course experiment during larval feeding in choice and no-choice experiments. Adult moths visit and prefers LL over AT for oviposition. Conversely, LL leaves were not preferred and proved detrimental for P. xylostella larvae. Aliphatic and indolic glucosinolates were found to decrease significantly (p≤0.05) in AT during initial 12h of P. xylostella challenge, whereas, they were not affected in LL. Also, MYB transcription factor expression and myrosinase activity in LL do not suggest a typical host response to a specialist insect. This preference-performance mismatch of P. xylostella on LL mediated by glucosinolate pattern suggests that this novel plant could be utilized in P. xylostella management. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Modulation of Host Learning in Aedes aegypti Mosquitoes.

PubMed

Vinauger, Clément; Lahondère, Chloé; Wolff, Gabriella H; Locke, Lauren T; Liaw, Jessica E; Parrish, Jay Z; Akbari, Omar S; Dickinson, Michael H; Riffell, Jeffrey A

2018-02-05

How mosquitoes determine which individuals to bite has important epidemiological consequences. This choice is not random; most mosquitoes specialize in one or a few vertebrate host species, and some individuals in a host population are preferred over others. Mosquitoes will also blood feed from other hosts when their preferred is no longer abundant, but the mechanisms mediating these shifts between hosts, and preferences for certain individuals within a host species, remain unclear. Here, we show that olfactory learning may contribute to Aedes aegypti mosquito biting preferences and host shifts. Training and testing to scents of humans and other host species showed that mosquitoes can aversively learn the scent of specific humans and single odorants and learn to avoid the scent of rats (but not chickens). Using pharmacological interventions, RNAi, and CRISPR gene editing, we found that modification of the dopamine-1 receptor suppressed their learning abilities. We further show through combined electrophysiological and behavioral recordings from tethered flying mosquitoes that these odors evoke changes in both behavior and antennal lobe (AL) neuronal responses and that dopamine strongly modulates odor-evoked responses in AL neurons. Not only do these results provide direct experimental evidence that olfactory learning in mosquitoes can play an epidemiological role, but collectively, they also provide neuroanatomical and functional demonstration of the role of dopamine in mediating this learning-induced plasticity, for the first time in a disease vector insect. Copyright © 2017 Elsevier Ltd. All rights reserved.

The consequences of alternating diet on performance and food preferences of a specialist leaf beetle.

PubMed

Tremmel, Martin; Müller, Caroline

2013-08-01

The food quality of a given host plant tissue will influence the performance and may also affect the preference behavior of herbivorous animals. As nutrient contents and defense metabolite concentrations can vary significantly between different parts of a plant and change over time, herbivores are potentially confronted with diet differing in quality even when feeding on a single plant individual. Here we investigated to what extent feeding exclusively either on young or old, mature leaves of Brassica rapa or on a mixed diet of young and old leaves offered in alternating order affects the larval performance, food consumption, and the host preference behavior of adult mustard leaf beetles, Phaedon cochleariae. Analyzing different leaf quality traits, we found lower water contents, no changes in C:N ratio but more than threefold higher glucosinolate concentrations in young compared to old leaves. Individuals reared on mixed diet performed as well as animals reared on young leaves. Thus, compared to animals feeding exclusively on highly nutritious young leaves, diet-mixing individuals may balance the lower nutrient intake by a dilution of adverse secondary metabolites. Alternatively, they may integrate over the variation in their food, using a previously assimilated resource for growth at times of scarcity. Animals reared on old leaves grew less and had a prolonged larval developmental time, although they showed increased consumption indicating compensatory feeding. Additionally, we found that experience with a certain diet affected the preference behavior. Whereas individuals reared exclusively on young leaves preferred young over old leaves for feeding and oviposition, we did not find any preferences by animals reared exclusively on old leaves or by females reared on alternating diet. Thus, in contrast to positive feedbacks for animals reared on young leaves, an integrative growth of diet-mixing individuals potentially leads to a lack of feedback during development. Taken together, our results suggest that different diet regimes can lead to comparable performance of mustard leaf beetles but experienced feedbacks may differ and thus convey distinct diet preferences. Copyright © 2013 Elsevier Ltd. All rights reserved.

Host shift and speciation in a coral-feeding nudibranch

PubMed Central

Faucci, Anuschka; Toonen, Robert J; Hadfield, Michael G

2006-01-01

While the role of host preference in ecological speciation has been investigated extensively in terrestrial systems, very little is known in marine environments. Host preference combined with mate choice on the preferred host can lead to population subdivision and adaptation leading to host shifts. We use a phylogenetic approach based on two mitochondrial genetic markers to disentangle the taxonomic status and to investigate the role of host specificity in the speciation of the nudibranch genus Phestilla (Gastropoda, Opisthobranchia) from Guam, Palau and Hawaii. Species of the genus Phestilla complete their life cycle almost entirely on their specific host coral (species of Porites, Goniopora and Tubastrea). They reproduce on their host coral and their planktonic larvae require a host-specific chemical cue to metamorphose and settle onto their host. The phylogenetic trees of the combined cytochrome oxidase I and ribosomal 16S gene sequences clarify the relationship among species of Phestilla identifying most of the nominal species as monophyletic clades. We found a possible case of host shift from Porites to Goniopora and Tubastrea in sympatric Phestilla spp. This represents one of the first documented cases of host shift as a mechanism underlying speciation in a marine invertebrate. Furthermore, we found highly divergent clades within Phestilla sp. 1 and Phestilla minor (8.1–11.1%), suggesting cryptic speciation. The presence of a strong phylogenetic signal for the coral host confirms that the tight link between species of Phestilla and their host coral probably played an important role in speciation within this genus. PMID:17134995

Host-seeking activity and avian host preferences of mosquitoes associated with West Nile virus transmission in the northeastern U.S.A.

USGS Publications Warehouse

Suom, Channsotha; Ginsberg, Howard S.; Bernick, Andrew; Klein, Coby; Buckley, P.A.; Salvatore, Christa; LeBrun, Roger A.

2010-01-01

Mosquito host-seeking activity was studied using a custom-designed trap to explore: (1) at which time interval of the night adult mosquito abatement would be most effective, and (2) if there exists an avian-specific host-seeking preference. Overnight trials using traps baited with dry ice showed that Aedes taeniorhynchus (Wiedemann) was most active at dusk and was then captured throughout the night. In contrast, Culex spp. (Cx. pipiens (Linnaeus) and Cx. restuans (Theobald) delayed most activity until about two h after dusk and were then captured through the night. This pattern suggests that management activities directed at adult Culex spp. would be most effective if initiated well after sunset. Mosquito capture rates in traps baited with birds in net bags were significantly greater than those with empty net bags, indicating that mosquitoes were attracted to the birds and not incidentally being sucked in by the custom trap's strong fan motor (Wilcoxon matched-pairs signed-ranks test, n = 24, t = 30, p 2 = 0.21, p = 0.02). Trials with paired traps that contained different native bird species showed that Gray Catbirds, Dumatella carolinensis, attracted more mosquitoes than the heavier Northern Cardinals, Cardinalis cardinalis (paired samples t-test, t = 2.58, df = 7, p = 0.04). However, attractiveness did not differ substantially among bird species, and Gray Catbirds did not attract more mosquitoes than all other birds combined as a group. American Robins, Turdus migratorius (n = 4) were comparable in attractiveness to other bird species, but not enough American Robins were captured for a comprehensive study of mosquito avian preference.

Positive feedback between mycorrhizal fungi and plants influences plant invasion success and resistance to invasion.

PubMed

Zhang, Qian; Yang, Ruyi; Tang, Jianjun; Yang, Haishui; Hu, Shuijin; Chen, Xin

2010-08-24

Negative or positive feedback between arbuscular mycorrhizal fungi (AMF) and host plants can contribute to plant species interactions, but how this feedback affects plant invasion or resistance to invasion is not well known. Here we tested how alterations in AMF community induced by an invasive plant species generate feedback to the invasive plant itself and affect subsequent interactions between the invasive species and its native neighbors. We first examined the effects of the invasive forb Solidago canadensis L. on AMF communities comprising five different AMF species. We then examined the effects of the altered AMF community on mutualisms formed with the native legume forb species Kummerowia striata (Thunb.) Schindl. and on the interaction between the invasive and native plants. The host preferences of the five AMF were also assessed to test whether the AMF form preferred mutualistic relations with the invasive and/or the native species. We found that S. canadensis altered AMF spore composition by increasing one AMF species (Glomus geosporum) while reducing Glomus mosseae, which is the dominant species in the field. The host preference test showed that S. canadensis had promoted the abundance of AMF species (G. geosporum) that most promoted its own growth. As a consequence, the altered AMF community enhanced the competitiveness of invasive S. canadensis at the expense of K. striata. Our results demonstrate that the invasive S. canadensis alters soil AMF community composition because of fungal-host preference. This change in the composition of the AMF community generates positive feedback to the invasive S. canadensis itself and decreases AM associations with native K. striata, thereby making the native K. striata less dominant.

Site preference of alloying elements in DO22-Ni3V phase: Phase-field and first-principles study

NASA Astrophysics Data System (ADS)

Zhang, Ding-Ni; Shangguan, Qian-Qian; Liu, Fu; Zhang, Ming-Yi

2015-07-01

Site preference of alloying elements in DO22-Ni3V phase was investigated using phase-field and first-principles method. The concentrations of alloying elements on sublattices of DO22-Ni3V phase were quantitatively studied using phase-field model based on microscopic diffusion equations. The phase-field computation results demonstrate that the concentration differences of alloying elements on the NiI and NiII site are attributed to the coordination environment difference. Host atoms Ni and substitutional ternary additions Al prefer to occupy NiI site. Antisite atoms V show site preference on the NiII site. Further reason of site preference of alloying elements on the two different Ni sites were studied using first-principles method to calculate the electronic structure of DO22-Ni3V phase. Calculation of density of states, orbitals population and charge population of the optimized Ni3V structure found that the electronic structures of NiI and NiII sites are different. Electronic structure difference, which is caused by coordination environment difference, is the essential reason for site selectivity behaviors of alloying elements on NiI and NiII sites.

Interspecific and host-related gene expression patterns in nematode-trapping fungi.

PubMed

Andersson, Karl-Magnus; Kumar, Dharmendra; Bentzer, Johan; Friman, Eva; Ahrén, Dag; Tunlid, Anders

2014-11-11

Nematode-trapping fungi are soil-living fungi that capture and kill nematodes using special hyphal structures called traps. They display a large diversity of trapping mechanisms and differ in their host preferences. To provide insights into the genetic basis for this variation, we compared the transcriptome expressed by three species of nematode-trapping fungi (Arthrobotrys oligospora, Monacrosporium cionopagum and Arthrobotrys dactyloides, which use adhesive nets, adhesive branches or constricting rings, respectively, to trap nematodes) during infection of two different plant-pathogenic nematode hosts (the root knot nematode Meloidogyne hapla and the sugar beet cyst nematode Heterodera schachtii). The divergence in gene expression between the fungi was significantly larger than that related to the nematode species being infected. Transcripts predicted to encode secreted proteins and proteins with unknown function (orphans) were overrepresented among the highly expressed transcripts in all fungi. Genes that were highly expressed in all fungi encoded endopeptidases, such as subtilisins and aspartic proteases; cell-surface proteins containing the carbohydrate-binding domain WSC; stress response proteins; membrane transporters; transcription factors; and transcripts containing the Ricin-B lectin domain. Differentially expressed transcripts among the fungal species encoded various lectins, such as the fungal fruit-body lectin and the D-mannose binding lectin; transcription factors; cell-signaling components; proteins containing a WSC domain; and proteins containing a DUF3129 domain. A small set of transcripts were differentially expressed in infections of different host nematodes, including peptidases, WSC domain proteins, tyrosinases, and small secreted proteins with unknown function. This is the first study on the variation of infection-related gene expression patterns in nematode-trapping fungi infecting different host species. A better understanding of these patterns will facilitate the improvements of these fungi in biological control programs, by providing molecular markers for screening programs and candidates for genetic manipulations of virulence and host preferences.

Volatiles associated with preferred and nonpreferred hosts of the nantucket pine tip moth, Rhyacionia frustrana

Treesearch

Christopher Asaro; Brian T. Sullivan; M.J. Dalusky; C. Wayne Berisford

2004-01-01

Ovipositing female Nantucket pine tip moth, Rhyacionia frustrana, prefer loblolly pine, Pinus taeda L., to slash pine, Pinus elliottii Englem. except during the first spring following planting of seedlings. Host discrimination by R. frustrana increases as seedlings develop, suggesting that...

Female fecundity variation affects reproducibility of experiments on host plant preference and acceptance in a phytophagous insect

PubMed Central

Schäpers, Alexander; Petrén, Hampus; Wheat, Christopher W.; Wiklund, Christer

2017-01-01

Reproducibility is a scientific cornerstone. Many recent studies, however, describe a reproducibility crisis and call for assessments of reproducibility across scientific domains. Here, we explore the reproducibility of a classic ecological experiment—that of assessing female host plant preference and acceptance in phytophagous insects, a group in which host specialization is a key driver of diversification. We exposed multiple cohorts of Pieris napi butterflies from the same population to traditional host acceptance and preference tests on three Brassicaceae host species. Whereas the host plant rank order was highly reproducible, the propensity to oviposit on low-ranked hosts varied significantly even among cohorts exposed to similar conditions. Much variation could be attributed to among-cohort variation in female fecundity, a trait strongly correlated both to female size and to the size of the nuptial gift a female receives during mating. Small males provide small spermatophores, and in our experiment small females that mated with small males had a disproportionally low propensity to oviposit on low-ranked hosts. Hence, our results provide empirical support to the theoretical prediction that female host utilization is strongly affected by non-genetic, environmental variation, and that such variation can affect the reproducibility of ecological experiments even under seemingly identical conditions. PMID:28202813

Expression differences in Aphidius ervi (Hymenoptera: Braconidae) females reared on different aphid host species

PubMed Central

Legeai, Fabrice; Gonzalez-Gonzalez, Angelica; Lavandero, Blas; Simon, Jean-Christophe

2017-01-01

The molecular mechanisms that allow generalist parasitoids to exploit many, often very distinct hosts are practically unknown. The wasp Aphidius ervi, a generalist koinobiont parasitoid of aphids, was introduced from Europe into Chile in the late 1970s to control agriculturally important aphid species. A recent study showed significant differences in host preference and host acceptance (infectivity) depending on the host A. ervi were reared on. In contrast, no genetic differentiation between A. ervi populations parasitizing different aphid species and aphids of the same species reared on different host plants was found in Chile. Additionally, the same study did not find any fitness effects in A. ervi if offspring were reared on a different host as their mothers. Here, we determined the effect of aphid host species (Sitobion avenae versus Acyrthosiphon pisum reared on two different host plants alfalfa and pea) on the transcriptome of adult A. ervi females. We found a large number of differentially expressed genes (between host species: head: 2,765; body: 1,216; within the same aphid host species reared on different host plants: alfalfa versus pea: head 593; body 222). As expected, the transcriptomes from parasitoids reared on the same host species (pea aphid) but originating from different host plants (pea versus alfalfa) were more similar to each other than the transcriptomes of parasitoids reared on a different aphid host and host plant (head: 648 and 1,524 transcripts; body: 566 and 428 transcripts). We found several differentially expressed odorant binding proteins and olfactory receptor proteins in particular, when we compared parasitoids from different host species. Additionally, we found differentially expressed genes involved in neuronal growth and development as well as signaling pathways. These results point towards a significant rewiring of the transcriptome of A. ervi depending on aphid-plant complex where parasitoids develop, even if different biotypes of a certain aphid host species (A. pisum) are reared on the same host plant. This difference seems to persist even after the different wasp populations were reared on the same aphid host in the laboratory for more than 50 generations. This indicates that either the imprinting process is very persistent or there is enough genetic/allelic variation between A. ervi populations. The role of distinct molecular mechanisms is discussed in terms of the formation of host fidelity. PMID:28852588

Halide ions complex and deprotonate dipicolinamides and isophthalamides: assessment by mass spectrometry and UV-visible spectroscopy.

PubMed

Carasel, I Alexandru; Yamnitz, Carl R; Winter, Rudolph K; Gokel, George W

2010-12-03

The F(-), Cl(-), and Br(-) binding selectivity of bis(p-nitroanilide)s of dipicolinic and isophthalic acids was studied by using competitive electrospray mass spectrometry and UV-Visible spectroscopy. Both hosts prefer binding Cl(-) over either F(-) or Br(-). Host deprotonation was observed to some extent in all experiments in which the host was exposed to halide ions. When F(-) was present, host deprotonation was often the major process, whereas little deprotonation was observed by Cl(-) or Br(-), which preferred complexation. A solution of either host changed color when mixed with a F(-), H(2)PO(4)(-), di- or triphenylacetate solution.

Host-Related Olfactory Behavior in a Fruit-Piercing Moth (Lepidoptera: Erebidae) in Far Eastern Russia

PubMed Central

Zaspel, Jennifer M.; Kononenko, Vladimir S.; Ignell, Rickard; Hill, Sharon R.

2016-01-01

The host preference of the economically important fruit piercing moth, Calyptra lata (Butler 1881), was studied when exposed to different fruits and the odors of those fruits in enclosed feeding assays and in a two-choice olfactometer. The fruits consisted of three ripe and locally available types: raspberries, cherries and plums. Moths were released in cages with the ripened fruit and observed for any feeding events, which were then documented. Moths fed on both raspberries and cherries, but not on plums. To test the role of olfactory cues in fruit preference, male moths were released singly in the two choice olfactometer, with one type of fruit odor released in one arm and background control air in the other. The behavior of the moths was recorded on video. Parameters scored were 1) time to take off, 2) flight duration and 3) total time to source contact. The moths showed a significant preference for raspberry odor, exhibited a neutral response to cherry odor and significantly avoided the odor of plums. These results indicate that Calyptra lata demonstrates selective polyphagic feeding behavior and uses olfactory cues from both preferred and non-preferred fruits to detect and locate potential food sources. The possible implications for pest control are discussed. PMID:27324579

Chilli thrips, Scirtothrips dorsalis: A potential threat to cotton production in the USA

USDA-ARS?s Scientific Manuscript database

Several greenhouse studies including host preference, age specific abundance, within plant distribution and seasonal abundance of a newly introduced thrips pest, Scirtothrips dorsalis Hood, were conducted to evaluate its pest status on cotton. Cotton was found to be the most preferred host among the...

Susceptibility to Plasmodium liver stage infection is altered by hepatocyte polyploidy.

PubMed

Austin, Laura S; Kaushansky, Alexis; Kappe, Stefan H I

2014-05-01

Plasmodium parasites infect hepatocytes of their mammalian hosts and undergo obligate liver stage development. The specific host cell attributes that are important for liver infection remain largely unknown. Several host signalling pathways are perturbed in infected hepatocytes, some of which are important in the generation of hepatocyte polyploidy. To test the functional consequence of polyploidy on liver infection, we infected hepatocytes with the rodent malaria parasite Plasmodium yoelii both in vitro and in vivo and examined the ploidy of infected and uninfected hepatocytes by flow cytometry. In both hepatoma cell lines and in the mouse liver, the fraction of polyploid cells was higher in the infected cell population than in the uninfected cell population. When the data were reanalysed by comparing the extent of Plasmodium infection within each ploidy subset, we found that infection rates were elevated in more highly polyploid cells and lower in diploid cells. Furthermore, we found that the parasite's preference for host cells with high ploidy is conserved among rodent malaria species and the human malaria parasite Plasmodium falciparum. This parasite preference for host cells of high ploidy cannot be explained by differences in hepatocyte size or DNA replication. We conclude that Plasmodium preferentially infects and develops in polyploid hepatocytes. © 2014 John Wiley & Sons Ltd.

Susceptibility to Plasmodium liver stage infection is altered by hepatocyte polyploidy

PubMed Central

Austin, Laura S.; Kaushansky, Alexis; Kappe, Stefan H.I.

2014-01-01

Summary Plasmodium parasites infect hepatocytes of their mammalian hosts and within undergo obligate liver stage development. The specific host cell attributes that are important for liver infection remain largely unknown. Several host signaling pathways are perturbed in infected hepatocytes, some of which are important in the generation of hepatocyte polyploidy. To test the functional consequence of polyploidy in liver infection, we infected hepatocytes with the rodent malaria parasite Plasmodium yoelii both in vitro and in vivo and examined the ploidy of infected and uninfected hepatocytes by flow cytometry. In both hepatoma cell lines and in the mouse liver, the fraction of polyploid cells was higher in the infected cell population than in the uninfected cell population. When the data were reanalyzed by comparing the extent of Plasmodium infection within each ploidy subset, we found that infection rates were elevated in more highly polyploid cells and lower in diploid cells. Furthermore, we found that the parasite’s preference for host cells with high ploidy is conserved among rodent malaria species and the human malaria parasite Plasmodium falciparum. This parasite preference for host cells of high ploidy cannot be explained by differences in hepatocyte size or DNA replication. We conclude that Plasmodium preferentially infects and develops in polyploid hepatocytes. PMID:24612025

Plum pox virus accumulates mutations in different genome parts during a long-term maintenance in Prunus host plants and passage in Nicotiana benthamiana.

PubMed

Vozárová, Z; Kamencayová, M; Glasa, M; Subr, Z

2013-01-01

Plum pox virus (PPV) isolates of the strain PPV-M prevalently infect peaches under natural conditions in Middle Europe. Comparison of complete genome sequences obtained from subisolates of a PPV-M isolate maintained experimentally over a 6-year period in different Prunus host species and passaged in Nicotiana benthamiana was performed with the aim to highlight the mutations potentially connected with the virus-host adaptation. The results showed that the lowest number of non-silent mutations was accumulated in PPV-M maintained in peach (original host species), approximately two times higher diversity was recorded in plum, apricot and N. benthamiana, indicating the genetic determination of the PPV host preference. The sequence variability of Prunus subisolates was distributed more or less evenly along the PPV genome and no amino acid motif could be outlined as responsible for the host adaptation. In N. benthamiana the mutations were accumulated notably in the P1 and P3 genes indicating their non-essentiality in the infection of this experimental host plant.

Host choice in a bivoltine bee: how sensory constraints shape innate foraging behaviors.

PubMed

Milet-Pinheiro, Paulo; Herz, Kerstin; Dötterl, Stefan; Ayasse, Manfred

2016-04-11

Many insects have multiple generations per year and cohorts emerging in different seasons may evolve their own phenotypes if they are subjected to different selection regimes. The bivoltine bee Andrena bicolor is reported to be polylectic and oligolectic (on Campanula) in the spring and summer generations, respectively. Neurological constraints are assumed to govern pollen diet in bees. However, evidence comes predominantly from studies with oligolectic bees. We have investigated how sensory constraints influence the innate foraging behavior of A. bicolor and have tested whether bees of different generations evolved behavioral and sensory polyphenism to cope better with the host flowers available in nature when they are active. Behavioral and sensory polyphenisms were tested in choice assays and electroantennographic analyses, respectively. In the bioassays, we found that females of both generations (1) displayed a similar innate relative reliance on visual and olfactory floral cues irrespective of the host plants tested; (2) did not prefer floral cues of Campanula to those of Taraxacum (or vice versa) and (3) did not display an innate preference for yellow and lilac colors. In the electroantennographic analyses, we found that bees of both generations responded to the same set of compounds. Overall, we did not detect seasonal polyphenism in any trait examined. The finding that bees of both generations are not sensory constrained to visit a specific host flower, which is in strict contrast to results from studies with oligolectic bees, suggest that also bees of the second generation have a flexibility in innate foraging behavior and that this is an adaptive trait in A. bicolor. We discuss the significance of our findings in context of the natural history of A. bicolor and in the broader context of host-range evolution in bees.

Mancae of the parasitic cymothoid isopod, Anilocra apogonae: early life history, host-specificity, and effect on growth and survival of preferred young cardinal fishes

NASA Astrophysics Data System (ADS)

Fogelman, R. M.; Grutter, A. S.

2008-09-01

Juvenile parasitic cymothoid isopods (mancae) can injure or kill fishes, yet few studies have investigated their biology. While the definitive host of the adult cymothoids is usually a single host from a particular fish species, mancae may use so-called optional intermediate hosts before settling on the definitive host. Little, however, is known about these early interactions. The cymothoid isopod, Anilocra apogonae, infests the definitive host, Cheilodipterus quinquelineatus. This study examined their host preference among potential optional intermediate hosts. Their effect on the growth and mortality of the young of three apogonid fishes, including the definitive host, was investigated. The number of mancae produced per brood was positively correlated with female length. When given a choice of intermediate hosts, significantly more mancae attached to Apogon trimaculatus (Apogonidae) than to Apogon nigrofasciatus. When presented with Ap. trimaculatus and Pomacentrus amboinensis (Pomacentridae), mancae only attached to Ap. trimaculatus suggesting that mancae may show a taxonomic affiliation with preferred hosts. Mancae fed on all three apogonid species, with C. quinquelineatus being fed on earlier than Ap. trimaculatus and Ap. nigrofasciatus. Mancae feeding frequency, adjusted for fish survival, was lowest on C. quinquelineatus and highest on Ap. trimaculatus. Infested apogonids had reduced growth and increased mortality compared with uninfested fish. A. apogonae mancae can use several species of young apogonid fishes as optional intermediate hosts. Via reduced growth and increased mortality, mancae have the potential to negatively influence definitive host populations and also other young species of apogonid fishes.

Ecological and Genetic Differences between Cacopsylla melanoneura (Hemiptera, Psyllidae) Populations Reveal Species Host Plant Preference

PubMed Central

Malagnini, Valeria; Pedrazzoli, Federico; Papetti, Chiara; Cainelli, Christian; Zasso, Rosaly; Gualandri, Valeria; Pozzebon, Alberto; Ioriatti, Claudio

2013-01-01

The psyllid Cacopsylla melanoneura is considered one of the vectors of ‘Candidatus Phytoplasma mali’, the causal agent of apple proliferation disease. In Northern Italy, overwintered C. melanoneura adults reach apple and hawthorn around the end of January. Nymph development takes place between March and the end of April. The new generation adults migrate onto conifers around mid-June and come back to the host plant species after overwintering. In this study we investigated behavioural differences, genetic differentiation and gene flow between samples of C. melanoneura collected from the two different host plants. Further analyses were performed on some samples collected from conifers. To assess the ecological differences, host-switching experiments were conducted on C. melanoneura samples collected from apple and hawthorn. Furthermore, the genetic structure of the samples was studied by genotyping microsatellite markers. The examined C. melanoneura samples performed better on their native host plant species. This was verified in terms of oviposition and development of the offspring. Data resulting from microsatellite analysis indicated a low, but statistically significant difference between collected-from-apple and hawthorn samples. In conclusion, both ecological and genetic results indicate a differentiation between C. melanoneura samples associated with the two host plants. PMID:23874980

Host selection and feeding preference of Agrilus planipennis (Coleoptera: Buprestidae) on ash (Fraxinus spp.)

Treesearch

Deepa S. Pureswaran; Therese M. Poland

2009-01-01

We studied the host selection behavior and feeding preference of the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae). A. planipennis is an exotic forest insect pest native to Asia that was discovered in North America in 2002 and is causing widespread mortality of ash trees (Fraxinus spp...

The sampling characteristics of electivity indices.

PubMed

Lechowicz, Martin J

1982-01-01

Electivity indices measure the utilization of food types (r) in relation to their abundance or availability in the environment (p). Foods that constitute a larger proportion of the diet than of the available foods are considered preferred; conversely those proportionately underrepresented in the diet are avoided. A food is eaten at random if its proportion in the diet equals its proportion in the environment. A family of electivity indices stemming from Ivlev's (1961) classic monograph exist and differ only in the particular algorithm used to calculate electivity from r and p.For each available index I graphed the values of electivity as contours for all combinations of r and p. These graphs are compared to illustrate the strengths and weaknesses of each index on the basis of the following criteria: 1) the value of the index when r=p for a food, 2) the symmetry of the electivity value as feeding deviates from random, 3) the possible range of index values, 4) the linearity of changes in electivity over the full range of r and p, 5) the sensitivity of the index to sampling errors, 6) the statistical testability of the electivity, and 7) the stability of the electivity value for a food type that changes relative abundance or occurs in combination with different food types. No one index ideally satisfies all the criteria.The host preferences of gypsy moth, Lymantria dispar, feeding on tree foliage in an undisturbed deciduous forest in southwestern Quebec, Canada were used to compare the available indices: Ivlev's electivity, E; Ivlev's forage ratio, E'; Jacob's modified electivity, D; Jacob's modified forage ratio, log Q; Chesson's alpha; Strauss' linear index, L; and Vanderploeg and Scavia's relativized electivity, E * . The electivity values calculated by each index differ one from another; host trees shown as preferred by one index will frequently appear avoided according to an alternative index. The rank order electivities for the 19 available host trees, however, are remarkably similar for all but Strauss' linear index, L. Populus grandidentata, Quercus rubra, Ostrya virginiana, and Amelanchier were the most preferred host trees in the sampled forest; Prunus serotina, Acer pensylvanicum, A. rubrum, Betula lutea, and Fraxinus americana were most avoided. The use of Vanderploeg and Scavia's E * index is recommended.

Infracommunity dynamics of chiggers (Trombiculidae) parasitic on a rodent.

PubMed

Barnard, Karlien; Krasnov, Boris R; Goff, Lee; Matthee, Sonja

2015-11-01

We studied the structure of chigger mite (Trombiculidae) communities parasitic on a South African rodent, Rhabdomys pumilio. We aimed to determine whether: (a) different chigger species differ in preferences for certain body areas of a host and (b) chigger assemblages among body areas of the same host individual, are structured and if so, whether the structure of these assemblages is aggregative or segregative. Rhabdomys pumilio is parasitized by seven chigger species belonging to six genera. The three most abundant species (Leptotrombidium sp. nr. muridium, Schoutedenichia sp. and Neoschoengastia sp. A) displayed a non-random distribution across the host body, with the two most abundant species (L. sp. nr. muridium and Schoutedenichia sp.) significantly associated with the tail area. In addition, whenever non-randomness of chigger co-occurrence in the same body area was recorded, it indicated positive but not negative co-occurrences of different species. This might be due to similarity of chigger species in resource needs and strategies to avoid host defence efforts.

Thermo-orientation and the movement of feather-feeding lice on hosts.

PubMed

Harbison, Christopher W; Boughton, Rachel M

2014-08-01

Temperature variation on the host is known to influence ectoparasite distributions. Ectoparasites may also use temperature gradients between host regions when moving on the host; however, tests are rare. Feather-feeding wing lice (Phthiraptera: Ischnocera) spend the majority of their time on the flight feathers of their avian hosts where they insert their bodies between feather barbs to escape host preening. However, because wing lice feed on downy abdominal feathers, they must repeatedly migrate between the flight feathers and body regions of their hosts. We performed a series of experiments that tested thermo-orientation in wing lice and evaluated its potential use during louse migrations between host regions. We found that wing lice can rapidly and accurately locate nearby heat targets that approximate host temperatures (37 C), demonstrating a capacity for directed thermo-orientation. We next tested the preference of wing lice for temperatures found along migration routes between bird flight feathers and their body regions. Wing lice could distinguish between temperatures found within distinct bird regions, and lice that had recently fed preferred the cooler temperatures (32 C), similar to those within bird flight feathers where they typically reside. However, when starved for 18-20 hr, wing lice shifted their preferences toward temperatures typical of bird body regions where they feed (36 C), demonstrating an ability to use thermal cues when moving between bird regions. We discuss the use of thermal cues during louse migration and microhabitat selection, as well as other potential impacts of thermo-orientation on host-parasite interactions.

Density-dependent sex ratio and sex-specific preference for host traits in parasitic bat flies.

PubMed

Szentiványi, Tamara; Vincze, Orsolya; Estók, Péter

2017-08-29

Deviation of sex ratios from unity in wild animal populations has recently been demonstrated to be far more prevalent than previously thought. Ectoparasites are prominent examples of this bias, given that their sex ratios vary from strongly female- to strongly male-biased both among hosts and at the metapopulation level. To date our knowledge is very limited on how and why these biased sex ratios develop. It was suggested that sex ratio and sex-specific aggregation of ectoparasites might be shaped by the ecology, behaviour and physiology of both hosts and their parasites. Here we investigate a highly specialised, hematophagous bat fly species with strong potential to move between hosts, arguably limited inbreeding effects, off-host developmental stages and extended parental care. We collected a total of 796 Nycteribia kolenatii bat flies from 147 individual bats using fumigation and subsequently determined their sex. We report a balanced sex ratio at the metapopulation level and a highly variable sex ratio among infrapopulations ranging from 100% male to 100% female. We show that infrapopulation sex ratio is not random and is highly correlated with infrapopulation size. Sex ratio is highly male biased in small and highly female biased in large infrapopulations. We show that this pattern is most probably the result of sex-specific preference in bat flies for host traits, most likely combined with a higher mobility of males. We demonstrate that female bat flies exert a strong preference for high host body condition and female hosts, while the distribution of males is more even. Our results suggest that locally biased sex ratios can develop due to sex-specific habitat preference of parasites. Moreover, it is apparent that the sex of both hosts and parasites need to be accounted for when a better understanding of host-parasite systems is targeted.

Museum specimens reveal loss of pollen host plants as key factor driving wild bee decline in The Netherlands.

PubMed

Scheper, Jeroen; Reemer, Menno; van Kats, Ruud; Ozinga, Wim A; van der Linden, Giel T J; Schaminée, Joop H J; Siepel, Henk; Kleijn, David

2014-12-09

Evidence for declining populations of both wild and managed bees has raised concern about a potential global pollination crisis. Strategies to mitigate bee loss generally aim to enhance floral resources. However, we do not really know whether loss of preferred floral resources is the key driver of bee decline because accurate assessment of host plant preferences is difficult, particularly for species that have become rare. Here we examine whether population trends of wild bees in The Netherlands can be explained by trends in host plants, and how this relates to other factors such as climate change. We determined host plant preference of bee species using pollen loads on specimens in entomological collections that were collected before the onset of their decline, and used atlas data to quantify population trends of bee species and their host plants. We show that decline of preferred host plant species was one of two main factors associated with bee decline. Bee body size, the other main factor, was negatively related to population trend, which, because larger bee species have larger pollen requirements than smaller species, may also point toward food limitation as a key factor driving wild bee loss. Diet breadth and other potential factors such as length of flight period or climate change sensitivity were not important in explaining twentieth century bee population trends. These results highlight the species-specific nature of wild bee decline and indicate that mitigation strategies will only be effective if they target the specific host plants of declining species.

Museum specimens reveal loss of pollen host plants as key factor driving wild bee decline in The Netherlands

PubMed Central

Scheper, Jeroen; Reemer, Menno; van Kats, Ruud; Ozinga, Wim A.; van der Linden, Giel T. J.; Schaminée, Joop H. J.; Siepel, Henk; Kleijn, David

2014-01-01

Evidence for declining populations of both wild and managed bees has raised concern about a potential global pollination crisis. Strategies to mitigate bee loss generally aim to enhance floral resources. However, we do not really know whether loss of preferred floral resources is the key driver of bee decline because accurate assessment of host plant preferences is difficult, particularly for species that have become rare. Here we examine whether population trends of wild bees in The Netherlands can be explained by trends in host plants, and how this relates to other factors such as climate change. We determined host plant preference of bee species using pollen loads on specimens in entomological collections that were collected before the onset of their decline, and used atlas data to quantify population trends of bee species and their host plants. We show that decline of preferred host plant species was one of two main factors associated with bee decline. Bee body size, the other main factor, was negatively related to population trend, which, because larger bee species have larger pollen requirements than smaller species, may also point toward food limitation as a key factor driving wild bee loss. Diet breadth and other potential factors such as length of flight period or climate change sensitivity were not important in explaining twentieth century bee population trends. These results highlight the species-specific nature of wild bee decline and indicate that mitigation strategies will only be effective if they target the specific host plants of declining species. PMID:25422416

Ability of a Generalist Seed Beetle to Colonize an Exotic Host: Effects of Host Plant Origin and Oviposition Host.

PubMed

Amarillo-Suárez, A; Repizo, A; Robles, J; Diaz, J; Bustamante, S

2017-08-01

The colonization of an exotic species by native herbivores is more likely to occur if that herbivore is a generalist. There is little information on the life-history mechanisms used by native generalist insects to colonize exotic hosts and how these mechanisms are affected by host properties. We examined the ability of the generalist seed beetle Stator limbatus Horn to colonize an exotic species. We compared its host preference, acceptability, performance, and egg size when ovipositing and developing on two native (Pithecellobium dulce (Roxb.) Benth and Senegalia riparia (Kunth)) and one exotic legume species (Leucaena leucocephala (Lam.)). We also analyzed the seed chemistry. We found that females recognize the exotic species as an unfavorable host for larval development and that they delayed oviposition and laid fewer and larger eggs on the exotic species than on the native species. Survivorship on the exotic host was 0%. Additionally, seeds of the native species contain five chemical compounds that are absent in the exotic species, and the exotic species contains three sterols, which are absent in the native legumes. Genetically based differences between beetles adapted to different hosts, plastic responses toward new hosts, and chemical differences among seeds are important in host colonization and recognition of the exotic host. In conclusion, the generalist nature of S. limbatus does not influence its ability to colonize L. leucocephala. Explanations for the colonization of exotic hosts by generalist native species and for the success of invasive species must be complemented with studies measuring local adaptation and plasticity.

Development of defoliating insects and their preferences for host plants under varying temperatures in a subtropical evergreen forest in eastern China

NASA Astrophysics Data System (ADS)

Jing, Jun; Xia, Lingdan; Li, Kai

2017-06-01

The aim of this work was to understand the development of defoliating insects and their preferences for host plants under varying temperatures in a subtropical evergreen broad-leaved forest in China. We measured the main developmental parameters of three typical defoliating insects (i.e., Ourapteryx ebuleata szechuana, Biston marginata, and Euproctis angulata) and their preferences for five host plants at temperatures from 16°C to 31°C at 3°C intervals in the Tiantong National Forest Research station in eastern China. The results showed the following. 1) An appropriate rise in temperature increases the survival rate with an increase in the number of offspring. The developmental durations for these three insects were shortened, and pupal weight increased with an increase in temperature. 2) A shift in the preference for host plants for these three insects was observedat elevated temperatures. They all preferred to feed on Schima superba and Castanopsis sclerophylla at elevated temperatures, showing an opposite response to the other three plants. The daily leaf consumption of the three insects was positively correlated with their feeding preference, with more leaves being consumed from the plants they preferred. 3) For O. ebuleata szechuana larvae, daily leaf consumption initially increased and then decreased with increasing temperatures. In contrast, Biston marginata and Euproctis angulata larvae consumed more leaves at elevated temperatures. The feeding preferences of O. ebuleata szechuana and Biston marginata were more sensitive to changing temperatures than that of Euproctis angulata laevae. We concluded that increased numbers of offspring and generations, pupal weights, and a shift in preference to two plants for these three defoliating insects might lead to severe damage to these two plants which would enhance the fragmentation and decrease the stability of the forest communities under changing temperatures. Meanwhile, the variations in the responses of defoliating insects to the changing temperatures should be taken into consideration for the pest management of forests to adapt to the changing climate.

Evolutionary responses to climate change in parasitic systems.

PubMed

Chaianunporn, Thotsapol; Hovestadt, Thomas

2015-08-01

Species may respond to climate change in many ecological and evolutionary ways. In this simulation study, we focus on the concurrent evolution of three traits in response to climate change, namely dispersal probability, temperature tolerance (or niche width), and temperature preference (optimal habitat). More specifically, we consider evolutionary responses in host species involved in different types of interaction, that is parasitism or commensalism, and for low or high costs of a temperature tolerance-fertility trade-off (cost of generalization). We find that host species potentially evolve all three traits simultaneously in response to increasing temperature but that the evolutionary response interacts and may be compensatory depending on the conditions. The evolutionary adjustment of temperature preference is slower in the parasitism than in commensalism scenario. Parasitism, in turn, selects for higher temperature tolerance and increased dispersal. High costs for temperature tolerance (i.e. generalization) restrict evolution of tolerance and thus lead to a faster response in temperature preference than that observed under low costs. These results emphasize the possible role of biotic interactions and the importance of 'multidimensional' evolutionary responses to climate change. © 2015 John Wiley & Sons Ltd.

Disruption of Vector Host Preference with Plant Volatiles May Reduce Spread of Insect-Transmitted Plant Pathogens.

PubMed

Martini, Xavier; Willett, Denis S; Kuhns, Emily H; Stelinski, Lukasz L

2016-05-01

Plant pathogens can manipulate the odor of their host; the odor of an infected plant is often attractive to the plant pathogen vector. It has been suggested that this odor-mediated manipulation attracts vectors and may contribute to spread of disease; however, this requires further broad demonstration among vector-pathogen systems. In addition, disruption of this indirect chemical communication between the pathogen and the vector has not been attempted. We present a model that demonstrates how a phytophathogen (Candidatus Liberibacter asiaticus) can increase its spread by indirectly manipulating the behavior of its vector (Asian citrus psyllid, Diaphorina citri Kuwayama). The model indicates that when vectors are attracted to pathogen-infected hosts, the proportion of infected vectors increases, as well as, the proportion of infected hosts. Additionally, the peak of infected host populations occurs earlier as compared with controls. These changes in disease dynamics were more important during scenarios with higher vector mortality. Subsequently, we conducted a series of experiments to disrupt the behavior of the Asian citrus psyllid. To do so, we exposed the vector to methyl salicylate, the major compound released following host infection with the pathogen. We observed that during exposure or after pre-exposure to methyl salicylate, the host preference can be altered; indeed, the Asian citrus psyllids were unable to select infected hosts over uninfected counterparts. We suggest mechanisms to explain these interactions and potential applications of disrupting herbivore host preference with plant volatiles for sustainable management of insect vectors.

Host choice and human blood index of Anopheles pseudopunctipennis in a village of the Andean valleys of Bolivia

PubMed Central

Lardeux, Frédéric; Loayza, Paola; Bouchité, Bernard; Chavez, Tamara

2007-01-01

Background The Human Blood Index (HBI, proportion of bloodmeals of a mosquito population obtained from man) is relevant to epidemiological assessment and to the modification of measures to interrupt malaria transmission since the vectorial capacity of the vector varies as the square of the HBI. Anopheles pseudopunctipennis is a main malaria vector in South America. Unfortunately, few data exist concerning HBI values in its range of distribution and none from Bolivia where this species is considered as an important malaria vector in the central Andes. Methods The host choice of An. pseudopunctipennis has been studied in Mataral, a characteristic village of the central Andes of Bolivia. Mosquito host feeding preference experiments (equal accessibility to host in homogenous environment) were monitored using baited mosquito nets in latin square designs. Host feeding selection experiments (natural feeding pattern in heterogeneous environment) was measured by bloodmeal analysis, using ELISA to determine the origin of blood. Mosquito bloodmeals were collected on various occasions, using various techniques in a variety of sampling sites. A survey of the possible blood sources has also been carried out in the village. Data were analysed with the forage ratio method. Results An. pseudopunctipennis chooses amongst hosts. Sheep, goats, donkeys and humans are the preferred hosts, while dogs, pigs and chicken are rarely bitten. An. pseudopunctipennis has an opportunistic behaviour, in particular within the preferred hosts. The HBI in Mataral is ≈40% and in the central Andes, may range from 30–50%, in accordance to other findings. A high proportion of mixed meals were encountered (8%), and cryptic meals are likely more numerous. There was no difference amongst the HBI from parous and nulliparous mosquitoes. Conclusion Forage ratio analysis is a powerful tool to interpret mosquito host choices. However, refinements in sampling strategies are still needed to derive accurate and precise HBIs that could be computed to compare or follow epidemiological situations. The low antropophily of An. pseudopunctipennis, associated with changing environmental conditions, leads to unstable malaria (Plasmodium vivax) transmission in the central Andes. The opportunistic behaviour of this vector may be used to attract mosquitoes to insecticide. Zooprophylaxis is a promising alternative control strategy. PMID:17241459

Low offspring survival in mountain pine beetle infesting the resistant Great Basin bristlecone pine supports the preference-performance hypothesis

Treesearch

Erika L. Eidson; Karen E. Mock; Barbara J. Bentz

2018-01-01

The preference-performance hypothesis states that ovipositing phytophagous insects will select host plants that are well-suited for their offspring and avoid host plants that do not support offspring performance (survival, development and fitness). The mountain pine beetle (Dendroctonus ponderosae), a native insect herbivore in western North America, can successfully...

Heritability of and strong single gene (Pgi) effects on life-history traits in the Glanville fritillary butterfly.

PubMed

Klemme, I; Hanski, I

2009-09-01

We estimated broad-sense heritabilities (H(2)) of 13 female and seven male life-history traits of the Glanville fritillary butterfly (Melitaea cinxia) under semi-natural conditions in a large outdoor population cage. The analysis was based on full-sib families collected as young larvae in the field and reared under common garden conditions. We found significant genetic variance in female lifespan, fecundity, number of matings and host-plant preference as well as in male body mass and mobility. Apart from host-plant preference, female traits that were more strongly correlated with lifetime reproductive success (LRS; measured as total number of eggs laid) had higher H(2). LRS itself exhibited significant heritability. Host-plant preference had very high H(2), consistent with a previously reported genetically determined geographical cline in host-plant preference in the study area. Lifespan and egg hatching rate were significantly associated with a SNP in the coding region of the Pgi gene, for which there is previous evidence for balancing selection. Selection on Pgi, which furthermore shows spatial and temporal variation, may maintain genetic variance in fitness-related life-history traits. In contrast, we found no strong evidence for life-history trade-offs.

Comparisons of host specificity in feather louse genera (Insecta: Phthiraptera: Philopteridae) parasitizing gulls (Aves: Laridae: Larus).

PubMed

Yamagishi, Ayaka; Yao, Izumi; Johnson, Kevin P; Yoshizawa, Kazunori

2014-06-01

Data from gene sequences and morphological structures were collected for the gull feather lice, Saemundssonia lari, Quadraceps punctatus, and Q. ornatus, parasitizing Larus crassirostris and L. schistisagus. Saemundssonia lari was collected from both gull species, and no detectable morphological and genetic differences were found between lice collected from the two different hosts. In contrast, Q. punctatus was only collected from L. crassirostris, whereas Q. ornatus was only collected from L. schistisagus. The two Quadraceps species were genetically highly divergent, and body-size differences corresponding to the gull's body size (Harrison's rule) were also detected between them. Both Quadraceps species were collected from the interbarb of the remex or rectrix, and a match in body size between the louse and the interbarb space may be important in escape from host preening defenses. In contrast, Saemundssonia is a head louse, inhabiting the finer feathers of the head and neck, which the bird cannot preen. A close match to host body size may be less important for lice in the head microhabitat. The differences in the pattern of host-specificity between Saemundssonia and Quadraceps on the two focal host species of this study were probably due to their different microhabitat preferences. More broadly, comparisons of the gene sequences of S. lari and Q. punctatus to those from other gull hosts showed that genetically almost undifferentiated populations of both species were distributed on wide range of gull species. Frequent interspecific hybridization of gulls is one possible factor that may allow these lice to maintain gene flow across multiple host species.

Host preferences of tabanid flies based on identification of blood meals by ELISA.

PubMed

Muzari, M O; Burgess, G W; Skerratt, L F; Jones, R E; Duran, T L

2010-12-15

Tabanid flies in Australia are potential vectors of the parasite Trypanosoma evansi which causes the animal disease surra. It is endemic to most of south-east Asia and could enter Australia, but evaluation of the potential impact of a surra incursion requires identification of the major hosts of Australian tabanids. This study investigated the natural pattern of feeding and host preference by tabanid flies of Townsville, north Queensland by identification of ingested blood in trap-caught tabanids using ELISA. The assays were developed for identification of horse, cow, macropod and pig blood meals. Macropods were the most frequent food source for each of six major tabanid species in the area. This did not vary with location for one species, Tabanus pallipennis, despite macropod densities being lower than other hosts such as cattle and horses in some locations. Feeding patterns on other hosts generally depended on availability and density of animals. All tabanid species fed on at least three of the host species tested and mixed meals were also commonly encountered, suggesting a level of opportunistic feeding in addition to a preference for macropods. Some of the blood meals detected were possibly from previous gonotrophic cycles. The results indicate that all tabanid species examined could potentially transmit surra and all the host types investigated could be affected, but macropods face the highest transmission risk. Copyright © 2010 Elsevier B.V. All rights reserved.

Physical objects as vehicles of cultural transmission: maintaining harmony and uniqueness through colored geometric patterns.

PubMed

Ishii, Keiko; Miyamoto, Yuri; Rule, Nicholas O; Toriyama, Rie

2014-02-01

We examined how cultural values of harmony and uniqueness are represented and maintained through physical media (i.e., colorings of geometric patterns) and how individuals play an active role in selecting and maintaining such cultural values. We found that colorings produced by European American adults and children were judged as more unique, whereas colorings produced by Japanese adults and children were judged as more harmonious, reflecting cultural differences in values. Harmony undergirded Japanese participants' preferences for colorings, whereas uniqueness undergirded European American participants' preferences for colorings. These cultural differences led participants to prefer own-culture colorings over other-culture colorings. Moreover, bicultural participants' preferences acculturated according to their identification with their host culture. Furthermore, child rearers in Japan and Canada gave feedback about the children's colorings that were consistent with their culture's values. These findings suggest that simple geometric patterns can embody cultural values that are socialized and reinforced from an early age.

Where are you sucking from? Using Stable Isotopes to understand Host Specificity in two Hemiparasitic plants above the tree line in Northern Sweden

NASA Astrophysics Data System (ADS)

Macias Sevde, A. S.

2012-12-01

By Alejandro Macias, Erik Hobbie, Ruth Varner, Kaitlyn Steele Hemiparasites are known to suck nutrients from nearby plants but their host specificity is not well understood. Hemiparasites are ecosystem engineers, limiting surrounding plant's growth, and decreasing local biodiversity. To better understand this phenomenon, the host specificities of two hemiparasitic angiosperms, Bartsia alpina , and Pedicularis lapponica were studied above the tree line along an elevational gradient in Sweden. B. alpina specialized in wetter environments, as indicated by their higher δ13C signature, and their growth among Salixsp.Betula nana, Bistorta vivipara, Viola biflora, Geranium sp., and Trollious europaeus. P. lapponica was common in drier, less species rich environments, known as heaths, where B. nana, Empetrum negrum, Phyllodoce coeruela, Vaccinium myrtillus and Vaccinium vitis-idaea are the most common species. P. lapponica had higher foliage δ13C due to its better water-use efficiency in a dry environment. Field survey data and δN15 values of both the foliage of the parasitic plants and their potential hosts were used to determine host specificity. Since the δN15 value of the hemiparasitic plant and its host are similar due to parasitism, it was determined that P. lapponica had a preference for plants with an ericoid mycorrhizal association, such as Vaccinium sp, and E. negrum, but not for the common P. coeruela. This does not support the idea found in the literature that P. lapponica has a preference for grasses. B. alpina was less host specific, associating with non-mycorrhizal, ericoid, and ectomycorhizal plants, such as Carex sp, Vaccinium sp., and S. lapponum. The ectomycorrhizal species, Salix sp., and B. nana, were both potential hosts for B. alpina and P. lapponica due to their presence among them. However, the isotopic data revealed that B. alpina had a preference for Salix sp., and P. lapponica had a preference for B. nana.

Dynamics of Vector-Host Interactions in Avian Communities in Four Eastern Equine Encephalitis Virus Foci in the Northeastern U.S.

PubMed Central

Molaei, Goudarz; Thomas, Michael C.; Muller, Tim; Medlock, Jan; Shepard, John J.; Armstrong, Philip M.; Andreadis, Theodore G.

2016-01-01

Background Eastern equine encephalitis (EEE) virus (Togaviridae, Alphavirus) is a highly pathogenic mosquito-borne zoonosis that is responsible for occasional outbreaks of severe disease in humans and equines, resulting in high mortality and neurological impairment in most survivors. In the past, human disease outbreaks in the northeastern U.S. have occurred intermittently with no apparent pattern; however, during the last decade we have witnessed recurring annual emergence where EEE virus activity had been historically rare, and expansion into northern New England where the virus had been previously unknown. In the northeastern U.S., EEE virus is maintained in an enzootic cycle involving the ornithophagic mosquito, Culiseta melanura, and wild passerine (perching) birds in freshwater hardwood swamps. However, the identity of key avian species that serve as principal virus reservoir and amplification hosts has not been established. The efficiency with which pathogen transmission occurs within an avian community is largely determined by the relative reservoir competence of each species and by ecological factors that influence contact rates between these avian hosts and mosquito vectors. Methodology and principle findings Contacts between vector mosquitoes and potential avian hosts may be directly quantified by analyzing the blood meal contents of field-collected specimens. We used PCR-based molecular methods and direct sequencing of the mitochondrial cytochrome b gene for profiling of blood meals in Cs. melanura, in an effort to quantify its feeding behavior on specific vertebrate hosts, and to infer epidemiologic implications in four historic EEE virus foci in the northeastern U.S. Avian point count surveys were conducted to determine spatiotemporal host community composition. Of 1,127 blood meals successfully identified to species level, >99% of blood meals were from 65 avian hosts in 27 families and 11 orders, and only seven were from mammalian hosts representing three species. We developed an empirically informed mathematical model for EEE virus transmission using Cs. melanura abundance and preferred and non-preferred avian hosts. To our knowledge this is the first mathematical model for EEE virus, a pathogen with many potential hosts, in the northeastern U.S. We measured strong feeding preferences for a number of avian species based on the proportion of mosquito blood meals identified from these bird species in relation to their observed frequencies. These included: American Robin, Tufted Titmouse, Common Grackle, Wood Thrush, Chipping Sparrow, Black-capped Chickadee, Northern Cardinal, and Warbling Vireo. We found that these bird species, most notably Wood Thrush, play a dominant role in supporting EEE virus amplification. It is also noteworthy that the competence of some of the aforementioned avian species for EEE virus has not been established. Our findings indicate that heterogeneity induced by mosquito host preference, is a key mediator of the epizootic transmission of vector-borne pathogens. Conclusion and significance Detailed knowledge of the vector-host interactions of mosquito populations in nature is essential for evaluating their vectorial capacity and for assessing the role of individual vertebrates as reservoir hosts involved in the maintenance and amplification of zoonotic agents of human diseases. Our study clarifies the host associations of Cs. melanura in four EEE virus foci in the northeastern U.S., identifies vector host preferences as the most important transmission parameter, and quantifies the contribution of preference-induced contact heterogeneity to enzootic transmission. Our study identifies Wood Thrush, American Robin and a few avian species that may serve as superspreaders of EEE virus. Our study elucidates spatiotemporal host species utilization by Cs. melanura in relation to avian host community. This research provides a basis to better understand the involvement of Cs. melanura and avian hosts in the transmission and ecology of EEE virus and the risk of human infection in virus foci. PMID:26751704

Dynamics of Vector-Host Interactions in Avian Communities in Four Eastern Equine Encephalitis Virus Foci in the Northeastern U.S.

PubMed

Molaei, Goudarz; Thomas, Michael C; Muller, Tim; Medlock, Jan; Shepard, John J; Armstrong, Philip M; Andreadis, Theodore G

2016-01-01

Eastern equine encephalitis (EEE) virus (Togaviridae, Alphavirus) is a highly pathogenic mosquito-borne zoonosis that is responsible for occasional outbreaks of severe disease in humans and equines, resulting in high mortality and neurological impairment in most survivors. In the past, human disease outbreaks in the northeastern U.S. have occurred intermittently with no apparent pattern; however, during the last decade we have witnessed recurring annual emergence where EEE virus activity had been historically rare, and expansion into northern New England where the virus had been previously unknown. In the northeastern U.S., EEE virus is maintained in an enzootic cycle involving the ornithophagic mosquito, Culiseta melanura, and wild passerine (perching) birds in freshwater hardwood swamps. However, the identity of key avian species that serve as principal virus reservoir and amplification hosts has not been established. The efficiency with which pathogen transmission occurs within an avian community is largely determined by the relative reservoir competence of each species and by ecological factors that influence contact rates between these avian hosts and mosquito vectors. Contacts between vector mosquitoes and potential avian hosts may be directly quantified by analyzing the blood meal contents of field-collected specimens. We used PCR-based molecular methods and direct sequencing of the mitochondrial cytochrome b gene for profiling of blood meals in Cs. melanura, in an effort to quantify its feeding behavior on specific vertebrate hosts, and to infer epidemiologic implications in four historic EEE virus foci in the northeastern U.S. Avian point count surveys were conducted to determine spatiotemporal host community composition. Of 1,127 blood meals successfully identified to species level, >99% of blood meals were from 65 avian hosts in 27 families and 11 orders, and only seven were from mammalian hosts representing three species. We developed an empirically informed mathematical model for EEE virus transmission using Cs. melanura abundance and preferred and non-preferred avian hosts. To our knowledge this is the first mathematical model for EEE virus, a pathogen with many potential hosts, in the northeastern U.S. We measured strong feeding preferences for a number of avian species based on the proportion of mosquito blood meals identified from these bird species in relation to their observed frequencies. These included: American Robin, Tufted Titmouse, Common Grackle, Wood Thrush, Chipping Sparrow, Black-capped Chickadee, Northern Cardinal, and Warbling Vireo. We found that these bird species, most notably Wood Thrush, play a dominant role in supporting EEE virus amplification. It is also noteworthy that the competence of some of the aforementioned avian species for EEE virus has not been established. Our findings indicate that heterogeneity induced by mosquito host preference, is a key mediator of the epizootic transmission of vector-borne pathogens. Detailed knowledge of the vector-host interactions of mosquito populations in nature is essential for evaluating their vectorial capacity and for assessing the role of individual vertebrates as reservoir hosts involved in the maintenance and amplification of zoonotic agents of human diseases. Our study clarifies the host associations of Cs. melanura in four EEE virus foci in the northeastern U.S., identifies vector host preferences as the most important transmission parameter, and quantifies the contribution of preference-induced contact heterogeneity to enzootic transmission. Our study identifies Wood Thrush, American Robin and a few avian species that may serve as superspreaders of EEE virus. Our study elucidates spatiotemporal host species utilization by Cs. melanura in relation to avian host community. This research provides a basis to better understand the involvement of Cs. melanura and avian hosts in the transmission and ecology of EEE virus and the risk of human infection in virus foci.

Agent-based mathematical modeling as a tool for estimating Trypanosoma cruzi vector-host contact rates.

PubMed

Yong, Kamuela E; Mubayi, Anuj; Kribs, Christopher M

2015-11-01

The parasite Trypanosoma cruzi, spread by triatomine vectors, affects over 100 mammalian species throughout the Americas, including humans, in whom it causes Chagas' disease. In the U.S., only a few autochthonous cases have been documented in humans, but prevalence is high in sylvatic hosts (primarily raccoons in the southeast and woodrats in Texas). The sylvatic transmission of T. cruzi is spread by the vector species Triatoma sanguisuga and Triatoma gerstaeckeri biting their preferred hosts and thus creating multiple interacting vector-host cycles. The goal of this study is to quantify the rate of contacts between different host and vector species native to Texas using an agent-based model framework. The contact rates, which represent bites, are required to estimate transmission coefficients, which can be applied to models of infection dynamics. In addition to quantitative estimates, results confirm host irritability (in conjunction with host density) and vector starvation thresholds and dispersal as determining factors for vector density as well as host-vector contact rates. Copyright © 2015 Elsevier B.V. All rights reserved.

Variation in preference and performance of Frankliniella occidentalis (Thysanoptera: Thripidae) on three strawberry cultivars.

PubMed

Rahman, Touhidur; Spafford, Helen; Broughton, Sonya

2010-10-01

Western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a major pest of strawberry, causing substantial yield loss through direct feeding on the flowers and fruit. Insecticides are the main method used for its control; however, F. occidentalis has developed resistance to insecticides from all major chemical classes. Chemical control is not a long-term strategy and integrated pest management is required. This study determined whether F. occidentalis damage could be reduced by host plant resistance or tolerance in three commercial strawberry cultivars (Fragaria X ananassa [Rosaceae]: 'Albion', 'Camarosa', and 'Camino Real'). Determination of resistance or tolerance to F. occidentalis was based on olfactory response, feeding damage, ovipositional preference, and host suitability for reproduction on leaves. F. occidentalis adults preferred to feed on Camarosa; however, if leaves had been fed on previously by conspecifics, there was no difference in feeding preference. Camarosa was the most preferred cultivar for oviposition, and more eggs were laid by F. occidentalis on Camarosa than either Albion or Camino Real. More larvae hatched and adults were reared from Camarosa than either Albion or Camino Real. The percentage of unhatched eggs, larvae, and pupae that died was highest on Camino Real. Survival rate was highest on Camarosa. Egg incubation, prepupation, pupation, and total developmental periods were shortest on Camarosa, but the larval period was longest on Camarosa. Camarosa was the most favorable cultivar for F. occidentalis population growth on leaves.

Taste preferences of the common vampire bat (Desmodus rotundus).

PubMed

Thompson, R D; Elias, D J; Shumake, S A; Gaddis, S E

1982-04-01

Taste preference tests, with simultaneous presentation of treated and untreated food, were administered to 24 common vampire bats (Desmodus rotundus). The bats received brief exposures to four different stimuli representing sweet, salty, sour, and bitter tastes, each at four different concentrations. Despite a strong location bias, the bats significantly (P < 0.01) avoided the highest concentrations of the salty, sour, and bitter tastes. Consumption of the sweet stimulus at all concentrations was similar to that of the untreated standard. Vampires evidently can discriminate based on taste, although their ability is apparently poorly developed when compared with some euryphagous species such as the rat. Hence, taste is probably not a factor in host selection by the vampire.

A structural model of polyglutamine determined from a host-guest method combining experiments and landscape theory.

PubMed

Finke, John M; Cheung, Margaret S; Onuchic, José N

2004-09-01

Modeling the structure of natively disordered peptides has proved difficult due to the lack of structural information on these peptides. In this work, we use a novel application of the host-guest method, combining folding theory with experiments, to model the structure of natively disordered polyglutamine peptides. Initially, a minimalist molecular model (C(alpha)C(beta)) of CI2 is developed with a structurally based potential and captures many of the folding properties of CI2 determined from experiments. Next, polyglutamine "guest" inserts of increasing length are introduced into the CI2 "host" model and the polyglutamine is modeled to match the resultant change in CI2 thermodynamic stability between simulations and experiments. The polyglutamine model that best mimics the experimental changes in CI2 thermodynamic stability has 1), a beta-strand dihedral preference and 2), an attractive energy between polyglutamine atoms 0.75-times the attractive energy between the CI2 host Go-contacts. When free-energy differences in the CI2 host-guest system are correctly modeled at varying lengths of polyglutamine guest inserts, the kinetic folding rates and structural perturbation of these CI2 insert mutants are also correctly captured in simulations without any additional parameter adjustment. In agreement with experiments, the residues showing structural perturbation are located in the immediate vicinity of the loop insert. The simulated polyglutamine loop insert predominantly adopts extended random coil conformations, a structural model consistent with low resolution experimental methods. The agreement between simulation and experimental CI2 folding rates, CI2 structural perturbation, and polyglutamine insert structure show that this host-guest method can select a physically realistic model for inserted polyglutamine. If other amyloid peptides can be inserted into stable protein hosts and the stabilities of these host-guest mutants determined, this novel host-guest method may prove useful to determine structural preferences of these intractable but biologically relevant protein fragments.

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...

Diverse Host-Seeking Behaviors of Skin-Penetrating Nematodes

PubMed Central

Castelletto, Michelle L.; Gang, Spencer S.; Okubo, Ryo P.; Tselikova, Anastassia A.; Nolan, Thomas J.; Platzer, Edward G.; Lok, James B.; Hallem, Elissa A.

2014-01-01

Skin-penetrating parasitic nematodes infect approximately one billion people worldwide and are responsible for some of the most common neglected tropical diseases. The infective larvae of skin-penetrating nematodes are thought to search for hosts using sensory cues, yet their host-seeking behavior is poorly understood. We conducted an in-depth analysis of host seeking in the skin-penetrating human parasite Strongyloides stercoralis, and compared its behavior to that of other parasitic nematodes. We found that Str. stercoralis is highly mobile relative to other parasitic nematodes and uses a cruising strategy for finding hosts. Str. stercoralis shows robust attraction to a diverse array of human skin and sweat odorants, most of which are known mosquito attractants. Olfactory preferences of Str. stercoralis vary across life stages, suggesting a mechanism by which host seeking is limited to infective larvae. A comparison of odor-driven behavior in Str. stercoralis and six other nematode species revealed that parasite olfactory preferences reflect host specificity rather than phylogeny, suggesting an important role for olfaction in host selection. Our results may enable the development of new strategies for combating harmful nematode infections. PMID:25121736

Considerations in the use of biologic grafts and alloplastic implants in facial plastic and reconstructive surgery.

PubMed

Boyce, R G; Toriumi, D M

1992-01-01

Surgical changes in the contour of soft tissue and bone of the craniomaxillofacial structures may require use of a biologic graft or alloplastic implant. Autologous materials are preferred; however, the harvesting procedure, donor site, and its associated morbidity are the disadvantages of using autografts. There are numerous types of alloplastic implants and they all differ in how they interact with host tissues. Factors such as implant texture, ability to integrate with host tissues, and rate of resorption all influence the overall success of different implants. In this article, we discuss some considerations in the use of biologic grafts and alloplastic implants in facial plastic and reconstructive surgery.

Role of Vision and Mechanoreception in Bed Bug, Cimex lectularius L. Behavior

PubMed Central

Singh, Narinderpal; Wang, Changlu; Cooper, Richard

2015-01-01

The role of olfactory cues such as carbon dioxide, pheromones, and kairomones in bed bug, Cimex lectularius L. behavior has been demonstrated. However, the role of vision and mechanoreception in bed bug behavior is poorly understood. We investigated bed bug vision by determining their responses to different colors, vertical objects, and their ability to detect colors and vertical objects under low and complete dark conditions. Results show black and red paper harborages are preferred compared to yellow, green, blue, and white harborages. A bed bug trapping device with a black or red exterior surface was significantly more attractive to bed bugs than that with a white exterior surface. Bed bugs exhibited strong orientation behavior toward vertical objects. The height (15 vs. 30 cm tall) and color (brown vs. black) of the vertical object had no significant effect on orientation behavior of bed bugs. Bed bugs could differentiate color and detect vertical objects at very low background light conditions, but not in complete darkness. Bed bug preference to different substrate textures (mechanoreception) was also explored. Bed bugs preferred dyed tape compared to painted tape, textured painted plastic, and felt. These results revealed that substrate color, presence of vertical objects, and substrate texture affect host-seeking and harborage-searching behavior of bed bugs. Bed bugs may use a combination of vision, mechanoreception, and chemoreception to locate hosts and seek harborages. PMID:25748041

Role of vision and mechanoreception in bed bug, Cimex lectularius L. behavior.

PubMed

Singh, Narinderpal; Wang, Changlu; Cooper, Richard

2015-01-01

The role of olfactory cues such as carbon dioxide, pheromones, and kairomones in bed bug, Cimex lectularius L. behavior has been demonstrated. However, the role of vision and mechanoreception in bed bug behavior is poorly understood. We investigated bed bug vision by determining their responses to different colors, vertical objects, and their ability to detect colors and vertical objects under low and complete dark conditions. Results show black and red paper harborages are preferred compared to yellow, green, blue, and white harborages. A bed bug trapping device with a black or red exterior surface was significantly more attractive to bed bugs than that with a white exterior surface. Bed bugs exhibited strong orientation behavior toward vertical objects. The height (15 vs. 30 cm tall) and color (brown vs. black) of the vertical object had no significant effect on orientation behavior of bed bugs. Bed bugs could differentiate color and detect vertical objects at very low background light conditions, but not in complete darkness. Bed bug preference to different substrate textures (mechanoreception) was also explored. Bed bugs preferred dyed tape compared to painted tape, textured painted plastic, and felt. These results revealed that substrate color, presence of vertical objects, and substrate texture affect host-seeking and harborage-searching behavior of bed bugs. Bed bugs may use a combination of vision, mechanoreception, and chemoreception to locate hosts and seek harborages.

Responses of Glossina morsitans morsitans to blends of electroantennographically active compounds in the odors of its preferred (buffalo and ox) and nonpreferred (waterbuck) hosts.

PubMed

Gikonyo, Nicholas K; Hassanali, Ahmed; Njagi, Peter G N; Saini, Rajinder K

2003-10-01

In a previous study, comparison of the behavior of teneral Glossina morsitans morsitans on waterbuck, Kobus defassa (a refractory host), and on two preferred hosts, buffalo, Syncerus caffer, and ox, Bos indicus, suggested the presence of allomones in the waterbuck odor. Examination of the volatile odors by coupled gas chromatography-electroantennographic detection showed that the antennal receptors of the flies detected constituents common to the three bovids (phenols and aldehydes), as well as a series of compounds specific to waterbuck, including C8-C13 methyl ketones, delta-octalactone, and phenols. In this study, behavioral respones of teneral G. m. morsitans to different blends of these compounds were evaluated in a choice wind tunnel. The flies' responses to known or putative attractant blends (the latter comprising EAG-active constituents common to all three animals and those common to buffalo and ox, excluding the known tseste attractants, 4-methylphenol and 3-n-propylphenol), and to putative repellent (the blend of EAG-active compounds specific to the waterbuck volatiles), were different. A major difference related to their initial and final behaviors. When a choice of attractant blends (known or putative) and clean air was presented, flies initially responded by flying upwind toward the odor source, but later moved downwind and rested on either side of the tunnel, with some preference for the side with the odor treatments. However, when presented with a choice of waterbuck-specific blend (putative repellent) and clean air, the flies' initial reaction appeared random; flies flew upwind on either side, but eventually settled down on the odorless side of the tunnel. Flies that flew up the odor plume showed an aversion behavior to the blend. The results lend further support to previous indications for the existence of a tsetse repellent blend in waterbuck body odor and additional attractive constituents in buffalo and ox body odors.

Cold temperature preference in bacterially infected Drosophila melanogaster improves survival but is remarkably suboptimal.

PubMed

Fedorka, Kenneth M; Kutch, Ian C; Collins, Louisa; Musto, Edward

Altering one's temperature preference (e.g. behavioral fever or behavioral chill) is a common immune defense among ectotherms that is likely to be evolutionarily conserved. However, the temperature chosen by an infected host may not be optimal for pathogen defense, causing preference to be inefficient. Here we examined the efficiency of temperature preference in Drosophila melanogaster infected with an LD 50 of the gram negative bacteria Pseudomonas aeruginosa. To this end, we estimated the host's uninfected and infected temperature preferences as well as their optimal survival temperature. We found that flies decreased their preference from 26.3°C to 25.2°C when infected, and this preference was stable over 48h. Furthermore, the decrease in temperature preference was associated with an increased chance of surviving the infection. Nevertheless, the infected temperature preference did not coincide with the optimum temperature for infection survival, which lies at or below 21.4°C. These data suggest that the behavioral response to P. aeruginosa infection is considerably inefficient, and the mechanisms that may account for this pattern are discussed. Future studies of infected temperature preferences should document its efficiency, as this understudied aspect of behavioral immunity can provide important insight into preference evolution. Copyright © 2016 Elsevier Ltd. All rights reserved.

How do we value a cure?

PubMed

Husereau, Don

2015-01-01

Future perceptions of the value of curative therapies will likely reflect debates happening today about preferences for funding of preventive versus treatment programs, as well as funding orphan drugs. Little is known about how society will value curative therapies versus standard treatments, and the significant role of a host of psychological factors compared to overarching concerns about opportunity costs will likely lead to significant tension between payers and the public. More research to clarify societal preferences and healthcare goals in regards to curative therapies and in light of the potential for significant opportunity costs will be required. Given what we know about preferences for the funding of prevention and treatment measures, we should expect that cures will not be held to a different measure.

Advancement of knowledge of Brucella over the past 50 years.

PubMed

Olsen, S C; Palmer, M V

2014-11-01

Fifty years ago, bacteria in the genus Brucella were known to cause infertility and reproductive losses. At that time, the genus was considered to contain only 3 species: Brucella abortus, Brucella melitensis, and Brucella suis. Since the early 1960s, at least 7 new species have been identified as belonging to the Brucella genus (Brucella canis, Brucella ceti, Brucella inopinata, Brucella microti, Brucella neotomae, Brucella ovis, and Brucella pinnipedialis) with several additional new species under consideration for inclusion. Although molecular studies have found such high homology that some authors have proposed that all Brucella are actually 1 species, the epidemiologic and diagnostic benefits for separating the genus based on phenotypic characteristics are more compelling. Although pathogenic Brucella spp have preferred reservoir hosts, their ability to infect numerous mammalian hosts has been increasingly documented. The maintenance of infection in new reservoir hosts, such as wildlife, has become an issue for both public health and animal health regulatory personnel. Since the 1960s, new information on how Brucella enters host cells and modifies their intracellular environment has been gained. Although the pathogenesis and histologic lesions of B. abortus, B. melitensis, and B. suis in their preferred hosts have not changed, additional knowledge on the pathology of these brucellae in new hosts, or of new species of Brucella in their preferred hosts, has been obtained. To this day, brucellosis remains a significant human zoonosis that is emerging or reemerging in many parts of the world. © The Author(s) 2014.

Evolution of habitat preference and nutrition mode in a cosmopolitan fungal genus with evidence of interkingdom host jumps and major shifts in ecology.

PubMed

Chaverri, Priscila; Samuels, Gary J

2013-10-01

Host jumps by microbial symbionts are often associated with bursts of species diversification driven by the exploitation of new adaptive zones. The objective of this study was to infer the evolution of habitat preference (decaying plants, soil, living fungi, and living plants), and nutrition mode (saprotrophy and mycoparasitism) in the fungal genus Trichoderma to elucidate possible interkingdom host jumps and shifts in ecology. Host and ecological role shifts were inferred by phylogenetic analyses and ancestral character reconstructions. The results support several interkingdom host jumps and also show that the preference for a particular habitat was gained or lost multiple times. Diversification analysis revealed that mycoparasitism is associated with accelerated speciation rates, which then suggests that this trait may be linked to the high number of species in Trichoderma. In this study it was also possible to infer the cryptic roles that endophytes or soil inhabitants play in their hosts by evaluating their closest relatives and determining their most recent ancestors. Findings from this study may have implications for understanding certain evolutionary processes such as species radiations in some hyperdiverse groups of fungi, and for more applied fields such as the discovery and development of novel biological control strategies. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Chemical and Mechanical Defenses Vary among Maternal Lines and Leaf Ages in Verbascum thapsus L. (Scrophulariaceae) and Reduce Palatability to a Generalist Insect

PubMed Central

Alba, Christina; Bowers, M. Deane; Blumenthal, Dana; Hufbauer, Ruth A.

2014-01-01

Intra-specific variation in host-plant quality affects herbivore foraging decisions and, in turn, herbivore foraging decisions mediate plant fitness. In particular, variation in defenses against herbivores, both among and within plants, shapes herbivore behavior. If variation in defenses is genetically based, it can respond to natural selection by herbivores. We quantified intra-specific variation in iridoid glycosides, trichome length, and leaf strength in common mullein (Verbascum thapsus L, Scrophulariaceae) among maternal lines within a population and among leaves within plants, and related this variation to feeding preferences of a generalist herbivore, Trichopulsia ni Hübner. We found significant variation in all three defenses among maternal lines, with T. ni preferring plants with lower investment in chemical, but not mechanical, defense. Within plants, old leaves had lower levels of all defenses than young leaves, and were strongly preferred by T. ni. Caterpillars also preferred leaves with trichomes removed to leaves with trichomes intact. Differences among maternal lines indicate that phenotypic variation in defenses likely has a genetic basis. Furthermore, these results reveal that the feeding behaviors of T. ni map onto variation in plant defense in a predictable way. This work highlights the importance of variation in host-plant quality in driving interactions between plants and their herbivores. PMID:25127229

A Multi-Year Study of Mosquito Feeding Patterns on Avian Hosts in a Southeastern Focus of Eastern Equine Encephalitis Virus

PubMed Central

Estep, Laura K.; McClure, Christopher J. W.; Burkett-Cadena, Nathan D.; Hassan, Hassan K.; Hicks, Tyler L.; Unnasch, Thomas R.; Hill, Geoffrey E.

2011-01-01

Eastern equine encephalitis virus (EEEV) is a mosquito-borne pathogen that cycles in birds but also causes severe disease in humans and horses. We examined patterns of avian host use by vectors of EEEV in Alabama from 2001 to 2009 using blood-meal analysis of field-collected mosquitoes and avian abundance surveys. The northern cardinal (Cardinalis cardinalis) was the only preferred host (fed on significantly more than expected based on abundance) of Culiseta melanura, the enzootic vector of EEEV. Preferred hosts of Culex erraticus, a putative bridge vector of EEEV, were American robin (Turdus migratorius), Carolina chickadee (Poecile carolinensis), barred owl (Strix varia), and northern mockingbird (Mimus polyglottis). Our results provide insight into the relationships between vectors of EEEV and their avian hosts in the Southeast and suggest that the northern cardinal may be important in the ecology of EEEV in this region. PMID:21540380

Field Studies Reveal Strong Postmating Isolation between Ecologically Divergent Butterfly Populations

PubMed Central

McBride, Carolyn S.; Singer, Michael C.

2010-01-01

Gene flow between populations that are adapting to distinct environments may be restricted if hybrids inherit maladaptive, intermediate phenotypes. This phenomenon, called extrinsic postzygotic isolation (EPI), is thought to play a critical role in the early stages of speciation. However, despite its intuitive appeal, we know surprisingly little about the strength and prevalence of EPI in nature, and even less about the specific phenotypes that tend to cause problems for hybrids. In this study, we searched for EPI among allopatric populations of the butterfly Euphydryas editha that have specialized on alternative host plants. These populations recall a situation thought typical of the very early stages of speciation. They lack consistent host-associated genetic differentiation at random nuclear loci and show no signs of reproductive incompatibility in the laboratory. However, they do differ consistently in diverse host-related traits. For each of these traits, we first asked whether hybrids between populations that use different hosts (different-host hybrids) were intermediate to parental populations and to hybrids between populations that use the same host (same-host hybrids). We then conducted field experiments to estimate the effects of intermediacy on fitness in nature. Our results revealed strong EPI under field conditions. Different-host hybrids exhibited an array of intermediate traits that were significantly maladaptive, including four behaviors. Intermediate foraging height slowed the growth of larvae, while intermediate oviposition preference, oviposition site height, and clutch size severely reduced the growth and survival of the offspring of adult females. We used our empirical data to construct a fitness surface on which different-host hybrids can be seen to fall in an adaptive valley between two peaks occupied by same-host hybrids. These findings demonstrate how ecological selection against hybrids can create a strong barrier to gene flow at the early stages of adaptive divergence. PMID:21048982

Host exopolysaccharide quantity and composition impact Erwinia amylovora bacteriophage pathogenesis.

PubMed

Roach, Dwayne R; Sjaarda, David R; Castle, Alan J; Svircev, Antonet M

2013-05-01

Erwinia amylovora bacteriophages (phages) belonging to the Myoviridae and Podoviridae families demonstrated a preference for either high-exopolysaccharide-producing (HEP) or low-exopolysaccharide-producing (LEP) bacterial hosts when grown on artificial medium without or with sugar supplementation. Myoviridae phages produced clear plaques on LEP hosts and turbid plaques on HEP hosts. The reverse preference was demonstrated by most Podoviridae phages, where clear plaques were seen on HEP hosts. Efficiency of plating (EOP) was determined by comparing phage growth on the original isolation host to the that on the LEP or HEP host. Nine of 10 Myoviridae phages showed highest EOPs on LEP hosts, and 8 of 11 Podoviridae phages had highest EOPs on HEP hosts. Increasing the production of EPS on sugar-supplemented medium or decreasing production by knocking out the synthesis of amylovoran or levan, the two EPSs produced by E. amylovora, indicated that these components play crucial roles in phage infection. Amylovoran was virtually essential for proliferation of most Podoviridae phages when phage population growth was compared to the wild type. Decreased levan production resulted in a significant reduction of progeny from phages in the Myoviridae family. Thus, Podoviridae phages are adapted to hosts that produce high levels of exopolysaccharides and are dependent on host-produced amylovoran for pathogenesis. Myoviridae phages are adapted to hosts that produce lower levels of exopolysaccharides and host-produced levan.

Host Exopolysaccharide Quantity and Composition Impact Erwinia amylovora Bacteriophage Pathogenesis

PubMed Central

Roach, Dwayne R.; Sjaarda, David R.; Svircev, Antonet M.

2013-01-01

Erwinia amylovora bacteriophages (phages) belonging to the Myoviridae and Podoviridae families demonstrated a preference for either high-exopolysaccharide-producing (HEP) or low-exopolysaccharide-producing (LEP) bacterial hosts when grown on artificial medium without or with sugar supplementation. Myoviridae phages produced clear plaques on LEP hosts and turbid plaques on HEP hosts. The reverse preference was demonstrated by most Podoviridae phages, where clear plaques were seen on HEP hosts. Efficiency of plating (EOP) was determined by comparing phage growth on the original isolation host to the that on the LEP or HEP host. Nine of 10 Myoviridae phages showed highest EOPs on LEP hosts, and 8 of 11 Podoviridae phages had highest EOPs on HEP hosts. Increasing the production of EPS on sugar-supplemented medium or decreasing production by knocking out the synthesis of amylovoran or levan, the two EPSs produced by E. amylovora, indicated that these components play crucial roles in phage infection. Amylovoran was virtually essential for proliferation of most Podoviridae phages when phage population growth was compared to the wild type. Decreased levan production resulted in a significant reduction of progeny from phages in the Myoviridae family. Thus, Podoviridae phages are adapted to hosts that produce high levels of exopolysaccharides and are dependent on host-produced amylovoran for pathogenesis. Myoviridae phages are adapted to hosts that produce lower levels of exopolysaccharides and host-produced levan. PMID:23503310

Intraspecific variation between the ITS sequences of Toxocara canis, Toxocara cati and Toxascaris leonina from different host species in south-western Poland.

PubMed

Fogt-Wyrwas, R; Mizgajska-Wiktor, H; Pacoń, J; Jarosz, W

2013-12-01

Some parasitic nematodes can inhabit different definitive hosts, which raises the question of the intraspecific variability of the nematode genotype affecting their preferences to choose particular species as hosts. Additionally, the issue of a possible intraspecific DNA microheterogeneity in specimens from different parts of the world seems to be interesting, especially from the evolutionary point of view. The problem was analysed in three related species - Toxocara canis, Toxocara cati and Toxascaris leonina - specimens originating from Central Europe (Poland). Using specific primers for species identification, internal transcribed spacer (ITS)-1 and ITS-2 regions were amplified and then sequenced. The sequences obtained were compared with sequences previously described for specimens originating from other geographical locations. No differences in nucleotide sequences were established in T. canis isolated from two different hosts (dogs and foxes). A comparison of ITS sequences of T. canis from Poland with sequences deposited in GenBank showed that the scope of intraspecific variability of the species did not exceed 0.4%, while in T. cati the differences did not exceed 2%. Significant differences were found in T. leonina, where ITS-1 differed by 3% and ITS-2 by as much as 7.4% in specimens collected from foxes in Poland and dogs in Australia. Such scope of differences in the nucleotide sequence seems to exceed the intraspecific variation of the species.

Variation in the Volatile Profiles of Black and Manchurian Ash in Relation to Emerald Ash Borer Oviposition Preferences.

PubMed

Rigsby, Chad M; McCartney, Nathaniel B; Herms, Daniel A; Tumlinson, James H; Cipollini, Don

2017-08-01

Emerald ash borer (EAB; Agrilus planipennis) is a devastating pest of ash (Fraxinus spp.) in its invaded range in North America. Its coevolved Asian hosts are more resistant and less preferred for oviposition than susceptible North American species. We compared EAB oviposition preferences and bark and canopy volatile organic compound (VOC) emissions of resistant Manchurian ash and susceptible black ash, and examined relationships between VOC profiles and oviposition. In the field, black ash was highly preferred for oviposition while no eggs were laid on Manchurian ash, and we found clear differences in the VOC profiles of Manchurian and black ash. We detected 78 compounds emitted from these species, including 16 compounds that elicited EAB antennal activity in prior studies. Four compounds were unique to black and 11 to Manchurian ash. Emission rates of 14 canopy and 19 bark volatiles varied among the two species, including four previously reported as antennally active. Specifically, 7-epi-sesquithujene (bark) emissions were greater from black ash, while β-caryophyllene (canopy), linalool (bark), and α-cubebene (bark) were emitted at higher rates by Manchurian ash. No relationships were found between the emission rate of any single compound or group of compounds (e.g. monoterpenes) suggesting that preference may be based on complex profile combinations. This is the first study to directly compare VOCs of black and Manchurian ash as well as the first to examine bark- and canopy-specific VOCs. The unique bark and canopy VOC profiles of these two species implicates potentially important variation in VOCs between a closely related resistant and susceptible species that provides a foundation for future studies of host preferences of EAB.

Interactions between Drosophila and its natural yeast symbionts-Is Saccharomyces cerevisiae a good model for studying the fly-yeast relationship?

PubMed

Hoang, Don; Kopp, Artyom; Chandler, James Angus

2015-01-01

Yeasts play an important role in the biology of the fruit fly, Drosophila melanogaster. In addition to being a valuable source of nutrition, yeasts affect D. melanogaster behavior and interact with the host immune system. Most experiments investigating the role of yeasts in D. melanogaster biology use the baker's yeast, Saccharomyces cerevisiae. However, S. cerevisiae is rarely found with natural populations of D. melanogaster or other Drosophila species. Moreover, the strain of S. cerevisiae used most often in D. melanogaster experiments is a commercially and industrially important strain that, to the best of our knowledge, was not isolated from flies. Since disrupting natural host-microbe interactions can have profound effects on host biology, the results from D. melanogaster-S. cerevisiae laboratory experiments may not be fully representative of host-microbe interactions in nature. In this study, we explore the D. melanogaster-yeast relationship using five different strains of yeast that were isolated from wild Drosophila populations. Ingested live yeasts have variable persistence in the D. melanogaster gastrointestinal tract. For example, Hanseniaspora occidentalis persists relative to S. cerevisiae, while Brettanomyces naardenensis is removed. Despite these differences in persistence relative to S. cerevisiae, we find that all yeasts decrease in total abundance over time. Reactive oxygen species (ROS) are an important component of the D. melanogaster anti-microbial response and can inhibit S. cerevisiae growth in the intestine. To determine if sensitivity to ROS explains the differences in yeast persistence, we measured yeast growth in the presence and absence of hydrogen peroxide. We find that B. naardenesis is completely inhibited by hydrogen peroxide, while H. occidentalis is not, which is consistent with yeast sensitivity to ROS affecting persistence within the D. melanogaster gastrointestinal tract. We also compared the feeding preference of D. melanogaster when given the choice between a naturally associated yeast and S. cerevisiae. We do not find a correlation between preferred yeasts and those that persist in the intestine. Notably, in no instances is S. cerevisiae preferred over the naturally associated strains. Overall, our results show that D. melanogaster-yeast interactions are more complex than might be revealed in experiments that use only S. cerevisiae. We propose that future research utilize other yeasts, and especially those that are naturally associated with Drosophila, to more fully understand the role of yeasts in Drosophila biology. Since the genetic basis of host-microbe interactions is shared across taxa and since many of these genes are initially discovered in D. melanogaster, a more realistic fly-yeast model system will benefit our understanding of host-microbe interactions throughout the animal kingdom.

Morphometric Differentiation Among Anastrepha fraterculus (Diptera: Tephritidae) Exploiting Sympatric Alternate Hosts.

PubMed

Gómez-Cendra, P V; Paulin, L E; Oroño, L; Ovruski, S M; Vilardi, J C

2016-04-01

Anastrepha fraterculus (Wiedemann) is currently considered a complex of cryptic species infesting fruits from Mexico to Argentina and represents an interesting biological model for evolutionary studies. Moreover, detecting and quantifying behavioral, morphological, and genetic differentiation among populations is also relevant to the application of environment-friendly control programs. Here, phenotypic differentiation among individuals coexisting in the wild in a Northern region of Argentina was unveiled and associated with host choice. Six morphometric traits were measured in sympatric flies exploiting three different host species. Phenotypic variation was shown to be host-dependent regardless of geographical or temporal overlap. Flies collected from synchronous alternate hosts (peach and walnut) differed from each other despite the lack of geographical isolation. By contrast, flies emerging from guavas that ripen about two months later than peach and walnut showed no significant differentiation in comparison to flies collected from walnuts, but they differ significantly from flies originating from peaches. This result is consistent with the hypothesis that the same population of flies shifts from walnuts to guavas throughout the year, whereas the population of flies that uses peaches as a host is probably exploiting other alternate hosts when peach availability decreases. Further research is needed to study the underlying mechanism. Results are consistent with previous molecular markers (inter-simple sequence repeat-ISSR) research on flies stemming from the same hosts and the same area, suggesting that differentiation among flies emerging from alternative hosts occurs at both genetic and phenotypic levels. The contribution of host preference in long-term genetic differentiation is discussed. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Macronutrient ratios in pollen shape bumble bee (Bombus impatiens) foraging strategies and floral preferences

PubMed Central

Vaudo, Anthony D.; Patch, Harland M.; Mortensen, David A.; Tooker, John F.; Grozinger, Christina M.

2016-01-01

To fuel their activities and rear their offspring, foraging bees must obtain a sufficient quality and quantity of nutritional resources from a diverse plant community. Pollen is the primary source of proteins and lipids for bees, and the concentrations of these nutrients in pollen can vary widely among host-plant species. Therefore we hypothesized that foraging decisions of bumble bees are driven by both the protein and lipid content of pollen. By successively reducing environmental and floral cues, we analyzed pollen-foraging preferences of Bombus impatiens in (i) host-plant species, (ii) pollen isolated from these host-plant species, and (iii) nutritionally modified single-source pollen diets encompassing a range of protein and lipid concentrations. In our semifield experiments, B. impatiens foragers exponentially increased their foraging rates of pollen from plant species with high protein:lipid (P:L) ratios; the most preferred plant species had the highest ratio (∼4.6:1). These preferences were confirmed in cage studies where, in pairwise comparisons in the absence of other floral cues, B. impatiens workers still preferred pollen with higher P:L ratios. Finally, when presented with nutritionally modified pollen, workers were most attracted to pollen with P:L ratios of 5:1 and 10:1, but increasing the protein or lipid concentration (while leaving ratios intact) reduced attraction. Thus, macronutritional ratios appear to be a primary factor driving bee pollen-foraging behavior and may explain observed patterns of host-plant visitation across the landscape. The nutritional quality of pollen resources should be taken into consideration when designing conservation habitats supporting bee populations. PMID:27357683

A Global Phylogeny of Leafmining Ectoedemia Moths (Lepidoptera: Nepticulidae): Exploring Host Plant Family Shifts and Allopatry as Drivers of Speciation

PubMed Central

Doorenweerd, Camiel; van Nieukerken, Erik J.; Menken, Steph B. J.

2015-01-01

Background Host association patterns in Ectoedemia (Lepidoptera: Nepticulidae) are also encountered in other insect groups with intimate plant relationships, including a high degree of monophagy, a preference for ecologically dominant plant families (e.g. Fagaceae, Rosaceae, Salicaceae, and Betulaceae) and a tendency for related insect species to feed on related host plant species. The evolutionary processes underlying these patterns are only partly understood, we therefore assessed the role of allopatry and host plant family shifts in speciation within Ectoedemia. Methodology Six nuclear and mitochondrial DNA markers with a total aligned length of 3692 base pairs were used to infer phylogenetic relationships among 92 species belonging to the subgenus Ectoedemia of the genus Ectoedemia, representing a thorough taxon sampling with a global coverage. The results support monophyletic species groups that are congruent with published findings based on morphology. We used the obtained phylogeny to explore host plant family association and geographical distribution to investigate if host shifts and allopatry have been instrumental in the speciation of these leafmining insects. Significance We found that, even though most species within species groups commonly feed on plants from one family, shifts to a distantly related host family have occasionally occurred throughout the phylogeny and such shifts are most commonly observed towards Betulaceae. The largest radiations have occurred within species groups that feed on Fagaceae, Rosaceae, and Salicaceae. Most species are restricted to one of the seven global biogeographic regions, but within species groups representatives are commonly found in different biogeographic regions. Although we find general patterns with regard to host use and biogeography, there are differences between clades that suggest that different drivers of speciation, and perhaps drivers that we did not examine, have shaped diversity patterns in different clades. PMID:25785630

Comparison of root-associated communities of native and non-native ectomycorrhizal hosts in an urban landscape.

PubMed

Lothamer, K; Brown, S P; Mattox, J D; Jumpponen, A

2014-05-01

Non-native tree species are often used as ornamentals in urban landscapes. However, their root-associated fungal communities remain yet to be examined in detail. Here, we compared richness, diversity and community composition of ectomycorrhizosphere fungi in general and ectomycorrhizal (EcM) fungi in particular between a non-native Pinus nigra and a native Quercus macrocarpa across a growing season in urban parks using 454-pyrosequencing. Our data show that, while the ectomycorrhizosphere community richness and diversity did not differ between the two host, the EcM communities associated with the native host were often more species rich and included more exclusive members than those of the non-native hosts. In contrast, the ectomycorrhizosphere communities of the two hosts were compositionally clearly distinct in nonmetric multidimensional ordination analyses, whereas the EcM communities were only marginally so. Taken together, our data suggest EcM communities with broad host compatibilities and with a limited numbers of taxa with preference to the non-native host. Furthermore, many common fungi in the non-native Pinus were not EcM taxa, suggesting that the fungal communities of the non-native host may be enriched in non-mycorrhizal fungi at the cost of the EcM taxa. Finally, while our colonization estimates did not suggest a shortage in EcM inoculum for either host in urban parks, the differences in the fungi associated with the two hosts emphasize the importance of using native hosts in urban environments as a tool to conserve endemic fungal diversity and richness in man-made systems.

Internet-usage patterns of immigrants in the process of intercultural adaptation.

PubMed

Chen, Wenli

2010-08-01

This paper investigates Internet-usage patterns of immigrants, and seeks to identify the correlation between Internet use and intercultural adaptation. The study focuses on mainland Chinese immigrants in Singapore, and was conducted via a nationwide telephone survey. The results show that immigrants tend to change their preferences on Internet use to reflect their residence in the host country. In particular, the longer an immigrant resides in the host country, the less likely they would be to surf their original country's websites and the more likely they would be to communicate with local people via the Internet. More importantly, differences in Internet usage are found to have a significant impact on immigrants' intercultural adaptation. In an online environment, the social communication in the host country is a critical component that can facilitate or impede immigrants' successful adaptation to the host country, whereas ethnic social communication also plays a role at the initial stage of transition.

Gypsy Moth Host Interactions: A Concept of Room and Board

Treesearch

William E.  Wallner

1983-01-01

The influence of host type and condition on the bioecology of gypsy moth are discussed from the viewpoint of room and board. Larval establishment was higher on preferred hosts; less than 5% migrated off them. Nonpreferred hosts lost 10-25% of larvae. Susceptibility of gypsy moth larvae to nucleopolyhedrosis virus increased following 1 or 2 years of defoliation....

Effects of citrus and avocado irrigation and nitrogen-form soil amendment on host selection by adult Homalodisca vitripennis (Hemiptera: Cicadellidae).

PubMed

Nadel, H; Seligmann, R; Johnson, M W; Hagler, J R; Stenger, D C; Groves, R L

2008-06-01

Host plant water status is thought to influence dispersal of the xylophagous leafhopper Homalodisca vitripennis Germar, especially where plants are grown under high evaporative demand. Preference by adult H. vitripennis for plants grown under different water deficit and nitrogen form fertilization regimens was studied under laboratory conditions. Leafhopper abundance and ovipositional preference were studied on potted 'Washington navel' orange and 'Haas' avocado in cage choice tests, and feeding rate was estimated using excreta produced by insects confined on plants. A similar study compared responses to citrus treated with 1:1 and 26:1 ratios of fertigated nitrate-N to ammonium-N. The insects were more abundant, oviposited, and fed significantly more on surplus-irrigated plants than on plants under moderate continuous deficit irrigation except avocado feeding, which was nearly significant. Plants exposed to drought became less preferred after 3 and 7 d in avocado and citrus, respectively. Citrus xylem fluid tension at this point was estimated at 0.93 MPa. A corresponding pattern of decline in feeding rate was observed on citrus, but on avocado, feeding rate was low overall and not statistically different between treatments. No statistical differences in abundance, oviposition, or feeding were detected on citrus fertigated with 26:1 or 1:1 ratios of nitrate-N to ammonium-N. Feeding occurred diurnally on both plant species. Discussion is provided on the potential deployment of regulated deficit irrigation to manage H. vitripennis movement as part of a multitactic effort to minimize the risk of disease outbreaks from Xylella fastidiosa Wells et al. in southern California agriculture.

Host plants of the wheat stem sawfly (Hymenoptera: Cephidae)

USDA-ARS?s Scientific Manuscript database

Wheat stem sawfly (Cephus cinctus Norton) is a pest of economic importance across much of the wheat cultivating areas of the western Great Plains as well as an ecologically important insect due to its wide range of grass hosts. Little research has been published involving the native host preference ...

Host-Plant Specialization Mediates the Influence of Plant Abundance on Host Use by Flower Head-Feeding Insects.

PubMed

Nobre, Paola A F; Bergamini, Leonardo L; Lewinsohn, Thomas M; Jorge, Leonardo R; Almeida-Neto, Mário

2016-02-01

Among-population variation in host use is a common phenomenon in herbivorous insects. The simplest and most trivial explanation for such variation in host use is the among-site variation in plant species composition. Another aspect that can influence spatial variation in host use is the relative abundance of each host-plant species compared to all available hosts. Here, we used endophagous insects that develop in flower heads of Asteraceae species as a study system to investigate how plant abundance influences the pattern of host-plant use by herbivorous insects with distinct levels of host-range specialization. Only herbivores recorded on three or more host species were included in this study. In particular, we tested two related hypotheses: 1) plant abundance has a positive effect on the host-plant preference of herbivorous insects, and 2) the relative importance of plant abundance to host-plant preference is greater for herbivorous species that use a wider range of host-plant species. We analyzed 11 herbivore species in 20 remnants of Cerrado in Southeastern Brazil. For 8 out of 11 herbivore species, plant abundance had a positive influence on host use. In contrast to our expectation, both the most specialized and the most generalist herbivores showed a stronger positive effect of plant species abundance in host use. Thus, we found evidence that although the abundance of plant species is a major factor determining the preferential use of host plants, its relative importance is mediated by the host-range specialization of herbivores.

Ethanol confers differential protection against generalist and specialist parasitoids of Drosophila melanogaster.

PubMed

Lynch, Zachary R; Schlenke, Todd A; Morran, Levi T; de Roode, Jacobus C

2017-01-01

As parasites coevolve with their hosts, they can evolve counter-defenses that render host immune responses ineffective. These counter-defenses are more likely to evolve in specialist parasites than generalist parasites; the latter face variable selection pressures between the different hosts they infect. Natural populations of the fruit fly Drosophila melanogaster are commonly threatened by endoparasitoid wasps in the genus Leptopilina, including the specialist L. boulardi and the generalist L. heterotoma, and both wasp species can incapacitate the cellular immune response of D. melanogaster larvae. Given that ethanol tolerance is high in D. melanogaster and stronger in the specialist wasp than the generalist, we tested whether fly larvae could use ethanol as an anti-parasite defense and whether its effectiveness would differ against the two wasp species. We found that fly larvae benefited from eating ethanol-containing food during exposure to L. heterotoma; we observed a two-fold decrease in parasitization intensity and a 24-fold increase in fly survival to adulthood. Although host ethanol consumption did not affect L. boulardi parasitization rates or intensities, it led to a modest increase in fly survival. Thus, ethanol conferred stronger protection against the generalist wasp than the specialist. We tested whether fly larvae can self-medicate by seeking ethanol-containing food after being attacked by wasps, but found no support for this hypothesis. We also allowed female flies to choose between control and ethanol-containing oviposition sites in the presence vs. absence of wasps and generally found significant preferences for ethanol regardless of wasp presence. Overall, our results suggest that D. melanogaster larvae obtain protection from certain parasitoid wasp species through their mothers' innate oviposition preferences for ethanol-containing food sources.

Ethanol confers differential protection against generalist and specialist parasitoids of Drosophila melanogaster

PubMed Central

Schlenke, Todd A.; Morran, Levi T.; de Roode, Jacobus C.

2017-01-01

As parasites coevolve with their hosts, they can evolve counter-defenses that render host immune responses ineffective. These counter-defenses are more likely to evolve in specialist parasites than generalist parasites; the latter face variable selection pressures between the different hosts they infect. Natural populations of the fruit fly Drosophila melanogaster are commonly threatened by endoparasitoid wasps in the genus Leptopilina, including the specialist L. boulardi and the generalist L. heterotoma, and both wasp species can incapacitate the cellular immune response of D. melanogaster larvae. Given that ethanol tolerance is high in D. melanogaster and stronger in the specialist wasp than the generalist, we tested whether fly larvae could use ethanol as an anti-parasite defense and whether its effectiveness would differ against the two wasp species. We found that fly larvae benefited from eating ethanol-containing food during exposure to L. heterotoma; we observed a two-fold decrease in parasitization intensity and a 24-fold increase in fly survival to adulthood. Although host ethanol consumption did not affect L. boulardi parasitization rates or intensities, it led to a modest increase in fly survival. Thus, ethanol conferred stronger protection against the generalist wasp than the specialist. We tested whether fly larvae can self-medicate by seeking ethanol-containing food after being attacked by wasps, but found no support for this hypothesis. We also allowed female flies to choose between control and ethanol-containing oviposition sites in the presence vs. absence of wasps and generally found significant preferences for ethanol regardless of wasp presence. Overall, our results suggest that D. melanogaster larvae obtain protection from certain parasitoid wasp species through their mothers’ innate oviposition preferences for ethanol-containing food sources. PMID:28700600

Host Reticulocytes Provide Metabolic Reservoirs That Can Be Exploited by Malaria Parasites

PubMed Central

Srivastava, Anubhav; Creek, Darren J.; Evans, Krystal J.; De Souza, David; Schofield, Louis; Müller, Sylke; Barrett, Michael P.; McConville, Malcolm J.; Waters, Andrew P.

2015-01-01

Human malaria parasites proliferate in different erythroid cell types during infection. Whilst Plasmodium vivax exhibits a strong preference for immature reticulocytes, the more pathogenic P. falciparum primarily infects mature erythrocytes. In order to assess if these two cell types offer different growth conditions and relate them to parasite preference, we compared the metabolomes of human and rodent reticulocytes with those of their mature erythrocyte counterparts. Reticulocytes were found to have a more complex, enriched metabolic profile than mature erythrocytes and a higher level of metabolic overlap between reticulocyte resident parasite stages and their host cell. This redundancy was assessed by generating a panel of mutants of the rodent malaria parasite P. berghei with defects in intermediary carbon metabolism (ICM) and pyrimidine biosynthesis known to be important for P. falciparum growth and survival in vitro in mature erythrocytes. P. berghei ICM mutants (pbpepc-, phosphoenolpyruvate carboxylase and pbmdh-, malate dehydrogenase) multiplied in reticulocytes and committed to sexual development like wild type parasites. However, P. berghei pyrimidine biosynthesis mutants (pboprt-, orotate phosphoribosyltransferase and pbompdc-, orotidine 5′-monophosphate decarboxylase) were restricted to growth in the youngest forms of reticulocytes and had a severe slow growth phenotype in part resulting from reduced merozoite production. The pbpepc-, pboprt- and pbompdc- mutants retained virulence in mice implying that malaria parasites can partially salvage pyrimidines but failed to complete differentiation to various stages in mosquitoes. These findings suggest that species-specific differences in Plasmodium host cell tropism result in marked differences in the necessity for parasite intrinsic metabolism. These data have implications for drug design when targeting mature erythrocyte or reticulocyte resident parasites. PMID:26042734

Assessment of Attractiveness of Plants as Roosting Sites for the Melon Fly, Bactrocera cucurbitae, and Oriental Fruit Fly, Bactrocera dorsalis

PubMed Central

McQuate, Grant T.; Vargas, Roger I.

2007-01-01

The use of toxic protein bait sprays to suppress melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), populations typically involves application to vegetation bordering agricultural host areas where the adults seek shelter (“roost”). Although bait spray applications for suppression of oriental fruit fly, Bactrocera dorsalis (Hendel), populations have traditionally been applied to the host crop, rather than to crop borders, roosting by oriental fruit flies in borders of some crop species, such as papaya, Carica papaya L. (Brassicales: Caricaceae), suggests that bait spray applications to crop borders could also help in suppression of B. dorsalis populations. In order to develop improved recommendations for application of bait sprays to border plants for suppression of melon fly and oriental fruit fly populations, the relative attractiveness of a range of plant species, in a vegetative (non-flowering) stage, was tested to wild melon fly and oriental fruit fly populations established in a papaya orchard in Hawaii. A total of 20 plant species were evaluated, divided into four categories: 1) border plants, including corn, Zea mays L. (Poales: Poaceae), windbreaks and broad-leaved ornamentals, 7 species; 2) weed plants commonly found in agricultural fields in Hawaii, 6 species; 3) host crop plants, 1 species- zucchini, Cucurbita pepo L. (Violales: Curcurbitaceae), and 4) locally grown fruit trees, 6 species. Plants were established in pots and placed in an open field, in clusters encircling protein bait traps, 20 m away from the papaya orchard. Castor bean, Ricinus communis L. (Euphorbiales: Euphorbiaceae), panax, Polyscias guilfoylei (Bull) Bailey (Apiales: Araliaceae), tiger's claw, Erythnna variegata L. (Fabales: Fabaceae), and guava, Psidium guajava L. (Myrtales: Myrtaceae) were identified as preferred roosting hosts for the melon fly, and tiger's claw, panax, castor bean, Canada cocklebur, Xanthium strumarium L. (Asterales: Asteraceae), Brazilian pepper tree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), ti plant, Cordyline terminate (L.) Chev.(Liliales: Liliaceae), guava and several Citrus spp. were identified as preferred roosting hosts for oriental fruit fly. Guava had not previously been identified as a preferred roosting host for melon fly. Other than for the use of panax as a roosting host, there has previously been little attention to roosting hosts for oriental fruit fly. Establishment of preferred roosting hosts as crop borders may help to improve suppression of both fruit fly species by providing sites for bait spray applications. Further research is needed to assess the use of vegetation bordering other host crops as roosting hosts, especially for oriental fruit fly. PMID:20334596

Phylogenetic congruence between subtropical trees and their associated fungi.

PubMed

Liu, Xubing; Liang, Minxia; Etienne, Rampal S; Gilbert, Gregory S; Yu, Shixiao

2016-12-01

Recent studies have detected phylogenetic signals in pathogen-host networks for both soil-borne and leaf-infecting fungi, suggesting that pathogenic fungi may track or coevolve with their preferred hosts. However, a phylogenetically concordant relationship between multiple hosts and multiple fungi in has rarely been investigated. Using next-generation high-throughput DNA sequencing techniques, we analyzed fungal taxa associated with diseased leaves, rotten seeds, and infected seedlings of subtropical trees. We compared the topologies of the phylogenetic trees of the soil and foliar fungi based on the internal transcribed spacer (ITS) region with the phylogeny of host tree species based on matK , rbcL , atpB, and 5.8S genes. We identified 37 foliar and 103 soil pathogenic fungi belonging to the Ascomycota and Basidiomycota phyla and detected significantly nonrandom host-fungus combinations, which clustered on both the fungus phylogeny and the host phylogeny. The explicit evidence of congruent phylogenies between tree hosts and their potential fungal pathogens suggests either diffuse coevolution among the plant-fungal interaction networks or that the distribution of fungal species tracked spatially associated hosts with phylogenetically conserved traits and habitat preferences. Phylogenetic conservatism in plant-fungal interactions within a local community promotes host and parasite specificity, which is integral to the important role of fungi in promoting species coexistence and maintaining biodiversity of forest communities.

Female butterflies adapt and allocate their progeny to the host-plant quality of their own larval experience.

PubMed

Cahenzli, Fabian; Wenk, Barbara A; Erhardt, Andreas

2015-07-01

Recent studies with diverse taxa have shown that parents can utilize their experience of the environment to adapt their offspring's phenotype to the same environmental conditions. Thus, offspring would then perform best under environmental conditions experienced by their parents due to transgenerational phenotypic plasticity. Such an effect has been dubbed transgenerational acclimatization. However, evidence that parents can subsequently ensure the appropriate environmental conditions in order that offspring benefit from transgenerational acclimatization has never been demonstrated. We reared Pieris rapae larvae in the parental generation on high-nitrogen and low-nitrogen host plants, and reared the offspring (F1) of both treatments again on high- and low-nitrogen plants. Furthermore, we tested if females prefer to oviposit on high- or low-nitrogen host plants in two-way choice tests. We here show not only that females adapt their offspring's phenotype to the host-plant quality that they themselves experienced, but that females also mainly oviposit on the host quality to which they adapt their offspring. Moreover, effects of larval host plant on oviposition preference of females increased across two generations in F1-females acclimatized to low-nitrogen host plants, showing an adaptive host shift from one generation to the next. These findings may have profound implications for host-race formation and sympatric speciation.

Effects of fertilization of four hemlock species on Adelges tsugae (Hemiptera: Adelgidae) growth and feeding preference of predators.

Treesearch

S.V. Joseph; James Hanula

2011-01-01

Understanding how fertilization affects host resistance to hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera:Adelgidae), is important because fertilizers are often used to grow resistant selections to a suitable size for testing. We evaluated four hemlock species (Tsuga) under three different fertilizer regimes to assess whether fertility affected resistance to...

Weight differences of male and female pupae of gypsy moth (Lymantria dispar) and host-sex preference by two parasitoid species Lymantrichneumon disparis and Exorista larvarum.

PubMed

Babaei, Mohammad-Reza; Barari, H; Kara, K

2009-03-01

Weight differences of male and female pupae of gypsy moth [Lymantria dispar L. (Lepidoptera: Lymantriidae)] and its two parasitoids Lymantrichneumon disparis (Poda) (Hymenoptera: Ichneumonidae) and Exorista larvarum (L.) (Diptera: Tachinidae) host preference were examined in this study. Lymantria dispar pupae were collected from trunks and branches of 20 Ironwood trees (Parotia persica) in two sampling dates, 10 July 2005 and 24 July 2005. The pest pupae were weighted and then saved at room temperature until adults of gypsy moth or its parasitoids emerged. The most L. dispar pupae collected in the first sampling were male whereas those in the second one were female and both male and female pupae in the second sampling were smaller than those in first sampling. The majority of male pupae (98.29%) were less than 0.6 g and most of female pupae (79.39%) were more than 0.6 g in weight. The most of L. disparis emerged from male pupae of L. dispar, whereas the majority of E. larvarum emerged from female pupae. Implications of the results for biological control strategy of gypsy moth are discussed.

[The role of animacy in European Portuguese relative clause attachment: evidence from production and comprehension tasks].

PubMed

Soares, Ana Paula; Fraga, Isabel; Comesaña, Montserrat; Piñeiro, Ana

2010-11-01

This work presents an analysis of the role of animacy in attachment preferences of relative clauses to complex noun phrases in European Portuguese (EP). The study of how the human parser solves this kind of syntactic ambiguities has been focus of extensive research. However, what is known about EP is both limited and puzzling. Additionally, as recent studies have stressed the importance of extra-syntactic variables in this process, two experiments were carried out to assess EP attachment preferences considering four animacy conditions: Study 1 used a sentence-completion-task, and Study 2 a self-paced reading task. Both studies indicate a significant preference for high attachment in EP. Furthermore, they showed that this preference was modulated by the animacy of the host NP: if the first host was inanimate and the second one was animate, the parser's preference changed to low attachment preference. These findings shed light on previous results regarding EP and strengthen the idea that, even in early stages of processing, the parser seems to be sensitive to extra-syntactic information.

Host-Feeding Preference of the Mosquito, Culex quinquefasciatus, in Yucatan State, Mexico

PubMed Central

Garcia-Rejon, Julian E.; Blitvich, Bradley J.; Farfan-Ale, Jose A.; Loroño-Pino, Maria A.; Chi Chim, Wilberth A.; Flores-Flores, Luis F.; Rosado-Paredes, Elsy; Baak-Baak, Carlos; Perez-Mutul, Jose; Suarez-Solis, Victor; Fernandez-Salas, Ildefonso; Beaty, Barry J.

2010-01-01

Studies were conducted to determine the host-feeding preference of Culex quinquefasciatus Say (Diptera: Culicidae) in relation to the availability of human and domestic animals in the city of Merida, Yucatan State, Mexico. Mosquitoes were collected in the backyards of houses using resting wooden boxes. Collections were made five times per week from January to December 2005. DNA was extracted from engorged females and tested by PCR using universal avian- and mammalian-specific primers. DNA extracted from avian-derived blood was further analyzed by PCR using primers that differentiate among the birds of three avian orders: Passeriformes, Columbiformes and Galliformes. PCR products obtained from mammalian-derived blood were subjected to restriction enzyme digestion to differentiate between human-, dog-, cat-, pig-, and horse-derived blood meals. Overall, 82% of engorged mosquitoes had fed on birds, and 18% had fed on mammals. The most frequent vertebrate hosts were Galliformes (47.1%), Passeriformes (23.8%), Columbiformes (11.2%) birds, and dogs (8.8%). The overall human blood index was 6.7%. The overall forage ratio for humans was 0.1, indicating that humans were not a preferred host for Cx. quinquefasciatus in Merida. PMID:20578953

Host-feeding preference of the mosquito, Culex quinquefasciatus, in Yucatan State, Mexico.

PubMed

Garcia-Rejon, Julian E; Blitvich, Bradley J; Farfan-Ale, Jose A; Loroño-Pino, Maria A; Chi Chim, Wilberth A; Flores-Flores, Luis F; Rosado-Paredes, Elsy; Baak-Baak, Carlos; Perez-Mutul, Jose; Suarez-Solis, Victor; Fernandez-Salas, Ildefonso; Beaty, Barry J

2010-01-01

Studies were conducted to determine the host-feeding preference of Culex quinquefasciatus Say (Diptera: Culicidae) in relation to the availability of human and domestic animals in the city of Merida, Yucatan State, Mexico. Mosquitoes were collected in the backyards of houses using resting wooden boxes. Collections were made five times per week from January to December 2005. DNA was extracted from engorged females and tested by PCR using universal avian- and mammalian-specific primers. DNA extracted from avian-derived blood was further analyzed by PCR using primers that differentiate among the birds of three avian orders: Passeriformes, Columbiformes and Galliformes. PCR products obtained from mammalian-derived blood were subjected to restriction enzyme digestion to differentiate between human-, dog-, cat-, pig-, and horse-derived blood meals. Overall, 82% of engorged mosquitoes had fed on birds, and 18% had fed on mammals. The most frequent vertebrate hosts were Galliformes (47.1%), Passeriformes (23.8%), Columbiformes (11.2%) birds, and dogs (8.8%). The overall human blood index was 6.7%. The overall forage ratio for humans was 0.1, indicating that humans were not a preferred host for Cx. quinquefasciatus in Merida.

Role of larval host plants in the climate-driven range expansion of the butterfly Polygonia c-album.

PubMed

Braschler, Brigitte; Hill, Jane K

2007-05-01

1. Some species have expanded their ranges during recent climate warming and the availability of breeding habitat and species' dispersal ability are two important factors determining expansions. The exploitation of a wide range of larval host plants should increase an herbivorous insect species' ability to track climate by increasing habitat availability. Therefore we investigated whether the performance of a species on different host plants changed towards its range boundary, and under warmer temperatures. 2. We studied the polyphagous butterfly Polygonia c-album, which is currently expanding its range in Britain and apparently has altered its host plant preference from Humulus lupulus to include other hosts (particularly Ulmus glabra and Urtica dioica). We investigated insect performance (development time, larval growth rate, adult size, survival) and adult flight morphology on these host plants under four rearing temperatures (18-28.5 degrees C) in populations from core and range margin sites. 3. In general, differences between core and margin populations were small compared with effects of rearing temperature and host plant. In terms of insect performance, host plants were generally ranked U. glabra > or = U. dioica > H. lupulus at all temperatures. Adult P. c-album can either enter diapause or develop directly and higher temperatures resulted in more directly developing adults, but lower survival rates (particularly on the original host H. lupulus) and smaller adult size. 4. Adult flight morphology of wild-caught individuals from range margin populations appeared to be related to increased dispersal potential relative to core populations. However, there was no difference in laboratory reared individuals, and conflicting results were obtained for different measures of flight morphology in relation to larval host plant and temperature effects, making conclusions about dispersal potential difficult. 5. Current range expansion of P. c-album is associated with the exploitation of more widespread host plants on which performance is improved. This study demonstrates how polyphagy may enhance the ability of species to track climate change. Our findings suggest that observed differences in climate-driven range shifts of generalist vs. specialist species may increase in the future and are likely to lead to greatly altered community composition.

Host- and stage-dependent secretome of the arbuscular mycorrhizal fungus Rhizophagus irregularis.

PubMed

Zeng, Tian; Holmer, Rens; Hontelez, Jan; Te Lintel-Hekkert, Bas; Marufu, Lucky; de Zeeuw, Thijs; Wu, Fangyuan; Schijlen, Elio; Bisseling, Ton; Limpens, Erik

2018-05-01

Arbuscular mycorrhizal fungi form the most wide-spread endosymbiosis with plants. There is very little host specificity in this interaction, however host preferences as well as varying symbiotic efficiencies have been observed. We hypothesize that secreted proteins (SPs) may act as fungal effectors to control symbiotic efficiency in a host-dependent manner. Therefore, we studied whether arbuscular mycorrhizal (AM) fungi adjust their secretome in a host- and stage-dependent manner to contribute to their extremely wide host range. We investigated the expression of SP-encoding genes of Rhizophagus irregularis in three evolutionary distantly related plant species, Medicago truncatula, Nicotiana benthamiana and Allium schoenoprasum. In addition we used laser microdissection in combination with RNA-seq to study SP expression at different stages of the interaction in Medicago. Our data indicate that most expressed SPs show roughly equal expression levels in the interaction with all three host plants. In addition, a subset shows significant differential expression depending on the host plant. Furthermore, SP expression is controlled locally in the hyphal network in response to host-dependent cues. Overall, this study presents a comprehensive analysis of the R. irregularis secretome, which now offers a solid basis to direct functional studies on the role of fungal SPs in AM symbiosis. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.

[Oviposition, development, and reproduction of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) fed on different hosts of economic importance].

PubMed

Barros, Eduardo M; Torres, Jorge B; Bueno, Adeney F

2010-01-01

The host selection for oviposition by Spodoptera frugiperda (J.E. Smith) among corn, millet, cotton and soybean, and its relationship with the biological characteristics were investigated. Free and non-choice tests for oviposition using plots containing five plants each, from each host in plastic greenhouse, resulted in similar oviposition preference among the host plants. In addition, selected biological characteristics of S. frugiperda were determined in the laboratory with larvae feeding on host leaves, and the combination of leaf and cotton boll. Neonate larvae exhibited low success of colonization on cotton boll compared to the leaves of all other hosts. Spodoptera frugiperda fed only on cotton bolls exhibited longer larval and pupal development, and longer adult life span; however with similar egg production. Larvae fed cotton leaves during six days and then transferred to cotton bolls, however, exhibited development and reproduction similar to those reared on corn or only on cotton leaves. Therefore, the variations on immature stages of S. frugiperda were not related with host selection for oviposition which was similar among the studied hosts. Based on our data, the millet as a winter, rotational, and cover crop is a potential host for S. frugiperda, while leaves and cotton bolls were diets of intermediate suitability as compared to corn and soybean leaves.

Can we disrupt the sensing of honey bees by the bee parasite Varroa destructor?

PubMed

Eliash, Nurit; Singh, Nitin Kumar; Kamer, Yosef; Pinnelli, Govardhana Reddy; Plettner, Erika; Soroker, Victoria

2014-01-01

The ectoparasitic mite, Varroa destructor, is considered to be one of the most significant threats to apiculture around the world. Chemical cues are known to play a significant role in the host-finding behavior of Varroa. The mites distinguish between bees from different task groups, and prefer nurses over foragers. We examined the possibility of disrupting the Varroa--honey bee interaction by targeting the mite's olfactory system. In particular, we examined the effect of volatile compounds, ethers of cis 5-(2'-hydroxyethyl) cyclopent-2-en-1-ol or of dihydroquinone, resorcinol or catechol. We tested the effect of these compounds on the Varroa chemosensory organ by electrophysiology and on behavior in a choice bioassay. The electrophysiological studies were conducted on the isolated foreleg. In the behavioral bioassay, the mite's preference between a nurse and a forager bee was evaluated. We found that in the presence of some compounds, the response of the Varroa chemosensory organ to honey bee headspace volatiles significantly decreased. This effect was dose dependent and, for some of the compounds, long lasting (>1 min). Furthermore, disruption of the Varroa volatile detection was accompanied by a reversal of the mite's preference from a nurse to a forager bee. Long-term inhibition of the electrophysiological responses of mites to the tested compounds was a good predictor for an alteration in the mite's host preference. These data indicate the potential of the selected compounds to disrupt the Varroa--honey bee associations, thus opening new avenues for Varroa control.

Behavioral evidence for host fidelity among populations of the parasitic wasp, Diachasma alloeum (Muesebeck)

NASA Astrophysics Data System (ADS)

Stelinski, L. L.; Liburd, O. E.

2005-02-01

The concept of “host fidelity,” where host-specific mating occurs in close proximity to the oviposition site and location of larval development, is thought to impart a pre-mating isolation mechanism for sympatric speciation (sensu members of the genus Rhagoletis). The apple maggot fly, Rhagoletis pomonella, and the blueberry maggot fly, R. mendax, are morphologically similar sibling species thought to have speciated in sympatry by divergence of host plant association. Both of these fly species are attacked by the specialist braconid parasitoid, Diachasma alloeum. The current study demonstrates that both male and female D. alloeum exhibit a behavioral preference for the odor of the fruit of their larval Rhagoletis host species. Specifically, those D. alloeum emerging from puparia of R. pomonella are preferentially attracted to hawthorn fruit and those emerging from puparia of R. mendax are preferentially attracted to blueberry fruit. However, male D. alloeum reared from either R. pomonella or R. mendax were equally attracted to females originating from both Rhagoletis species. We suggest that the data herein present evidence for “host fidelity,” where populations of D. alloeum exhibit a greater tendency to mate and reproduce among the host plants of their preferred Rhagoletis hosts. Furthermore, host fidelity may have resulted in the evolution of distinct host races of D. alloeum tracking the speciation of their larval Rhagoletis prey.

Molecular mechanisms of retroviral integration site selection

PubMed Central

Kvaratskhelia, Mamuka; Sharma, Amit; Larue, Ross C.; Serrao, Erik; Engelman, Alan

2014-01-01

Retroviral replication proceeds through an obligate integrated DNA provirus, making retroviral vectors attractive vehicles for human gene-therapy. Though most of the host cell genome is available for integration, the process of integration site selection is not random. Retroviruses differ in their choice of chromatin-associated features and also prefer particular nucleotide sequences at the point of insertion. Lentiviruses including HIV-1 preferentially integrate within the bodies of active genes, whereas the prototypical gammaretrovirus Moloney murine leukemia virus (MoMLV) favors strong enhancers and active gene promoter regions. Integration is catalyzed by the viral integrase protein, and recent research has demonstrated that HIV-1 and MoMLV targeting preferences are in large part guided by integrase-interacting host factors (LEDGF/p75 for HIV-1 and BET proteins for MoMLV) that tether viral intasomes to chromatin. In each case, the selectivity of epigenetic marks on histones recognized by the protein tether helps to determine the integration distribution. In contrast, nucleotide preferences at integration sites seem to be governed by the ability for the integrase protein to locally bend the DNA duplex for pairwise insertion of the viral DNA ends. We discuss approaches to alter integration site selection that could potentially improve the safety of retroviral vectors in the clinic. PMID:25147212

Mountain pine beetle host selection between lodgepole and ponderosa pines in the southern Rocky Mountains

USGS Publications Warehouse

West, Daniel R.; Briggs, Jenny S.; Jacobi, William R.; Negron, Jose F.

2016-01-01

Recent evidence of range expansion and host transition by mountain pine beetle ( Dendroctonus ponderosae Hopkins; MPB) has suggested that MPB may not primarily breed in their natal host, but will switch hosts to an alternate tree species. As MPB populations expanded in lodgepole pine forests in the southern Rocky Mountains, we investigated the potential for movement into adjacent ponderosa pine forests. We conducted field and laboratory experiments to evaluate four aspects of MPB population dynamics and host selection behavior in the two hosts: emergence timing, sex ratios, host choice, and reproductive success. We found that peak MPB emergence from both hosts occurred simultaneously between late July and early August, and the sex ratio of emerging beetles did not differ between hosts. In two direct tests of MPB host selection, we identified a strong preference by MPB for ponderosa versus lodgepole pine. At field sites, we captured naturally emerging beetles from both natal hosts in choice arenas containing logs of both species. In the laboratory, we offered sections of bark and phloem from both species to individual insects in bioassays. In both tests, insects infested ponderosa over lodgepole pine at a ratio of almost 2:1, regardless of natal host species. Reproductive success (offspring/female) was similar in colonized logs of both hosts. Overall, our findings suggest that MPB may exhibit equally high rates of infestation and fecundity in an alternate host under favorable conditions.

Evolutionary interpretations of mycobacteriophage biodiversity and host-range through the analysis of codon usage bias.

PubMed

Esposito, Lauren A; Gupta, Swati; Streiter, Fraida; Prasad, Ashley; Dennehy, John J

2016-10-01

In an genomics course sponsored by the Howard Hughes Medical Institute (HHMI), undergraduate students have isolated and sequenced the genomes of more than 1,150 mycobacteriophages, creating the largest database of sequenced bacteriophages able to infect a single host, Mycobacterium smegmatis , a soil bacterium. Genomic analysis indicates that these mycobacteriophages can be grouped into 26 clusters based on genetic similarity. These clusters span a continuum of genetic diversity, with extensive genomic mosaicism among phages in different clusters. However, little is known regarding the primary hosts of these mycobacteriophages in their natural habitats, nor of their broader host ranges. As such, it is possible that the primary host of many newly isolated mycobacteriophages is not M. smegmatis , but instead a range of closely related bacterial species. However, determining mycobacteriophage host range presents difficulties associated with mycobacterial cultivability, pathogenicity and growth. Another way to gain insight into mycobacteriophage host range and ecology is through bioinformatic analysis of their genomic sequences. To this end, we examined the correlations between the codon usage biases of 199 different mycobacteriophages and those of several fully sequenced mycobacterial species in order to gain insight into the natural host range of these mycobacteriophages. We find that UPGMA clustering tends to match, but not consistently, clustering by shared nucleotide sequence identify. In addition, analysis of GC content, tRNA usage and correlations between mycobacteriophage and mycobacterial codon usage bias suggests that the preferred host of many clustered mycobacteriophages is not M. smegmatis but other, as yet unknown, members of the mycobacteria complex or closely allied bacterial species.

Evolutionary interpretations of mycobacteriophage biodiversity and host-range through the analysis of codon usage bias

PubMed Central

Esposito, Lauren A.; Gupta, Swati; Streiter, Fraida; Prasad, Ashley

2016-01-01

In an genomics course sponsored by the Howard Hughes Medical Institute (HHMI), undergraduate students have isolated and sequenced the genomes of more than 1,150 mycobacteriophages, creating the largest database of sequenced bacteriophages able to infect a single host, Mycobacterium smegmatis, a soil bacterium. Genomic analysis indicates that these mycobacteriophages can be grouped into 26 clusters based on genetic similarity. These clusters span a continuum of genetic diversity, with extensive genomic mosaicism among phages in different clusters. However, little is known regarding the primary hosts of these mycobacteriophages in their natural habitats, nor of their broader host ranges. As such, it is possible that the primary host of many newly isolated mycobacteriophages is not M. smegmatis, but instead a range of closely related bacterial species. However, determining mycobacteriophage host range presents difficulties associated with mycobacterial cultivability, pathogenicity and growth. Another way to gain insight into mycobacteriophage host range and ecology is through bioinformatic analysis of their genomic sequences. To this end, we examined the correlations between the codon usage biases of 199 different mycobacteriophages and those of several fully sequenced mycobacterial species in order to gain insight into the natural host range of these mycobacteriophages. We find that UPGMA clustering tends to match, but not consistently, clustering by shared nucleotide sequence identify. In addition, analysis of GC content, tRNA usage and correlations between mycobacteriophage and mycobacterial codon usage bias suggests that the preferred host of many clustered mycobacteriophages is not M. smegmatis but other, as yet unknown, members of the mycobacteria complex or closely allied bacterial species. PMID:28348827

Neospora caninum Recruits Host Cell Structures to Its Parasitophorous Vacuole and Salvages Lipids from Organelles

PubMed Central

Nolan, Sabrina J.; Luechtefeld, Thomas

2015-01-01

Toxoplasma gondii and Neospora caninum, which cause the diseases toxoplasmosis and neosporosis, respectively, are two closely related apicomplexan parasites. They have similar heteroxenous life cycles and conserved genomes and share many metabolic features. Despite these similarities, T. gondii and N. caninum differ in their transmission strategies and zoonotic potential. Comparative analyses of the two parasites are important to identify the unique biological features that underlie the basis of host preference and pathogenicity. T. gondii and N. caninum are obligate intravacuolar parasites; in contrast to T. gondii, events that occur during N. caninum infection remain largely uncharacterized. We examined the capability of N. caninum (Liverpool isolate) to interact with host organelles and scavenge nutrients in comparison to that of T. gondii (RH strain). N. caninum reorganizes the host microtubular cytoskeleton and attracts endoplasmic reticulum (ER), mitochondria, lysosomes, multivesicular bodies, and Golgi vesicles to its vacuole though with some notable differences from T. gondii. For example, the host ER gathers around the N. caninum parasitophorous vacuole (PV) but does not physically associate with the vacuolar membrane; the host Golgi apparatus surrounds the N. caninum PV but does not fragment into ministacks. N. caninum relies on plasma lipoproteins and scavenges cholesterol from NPC1-containing endocytic organelles. This parasite salvages sphingolipids from host Golgi Rab14 vesicles that it sequesters into its vacuole. Our data highlight a remarkable degree of conservation in the intracellular infection program of N. caninum and T. gondii. The minor differences between the two parasites related to the recruitment and rearrangement of host organelles around their vacuoles likely reflect divergent evolutionary paths. PMID:25750213

Distinct antimicrobial peptide expression determines host species-specific bacterial associations

PubMed Central

Franzenburg, Sören; Walter, Jonas; Künzel, Sven; Wang, Jun; Baines, John F.; Bosch, Thomas C. G.; Fraune, Sebastian

2013-01-01

Animals are colonized by coevolved bacterial communities, which contribute to the host’s health. This commensal microbiota is often highly specific to its host-species, inferring strong selective pressures on the associated microbes. Several factors, including diet, mucus composition, and the immune system have been proposed as putative determinants of host-associated bacterial communities. Here we report that species-specific antimicrobial peptides account for different bacterial communities associated with closely related species of the cnidarian Hydra. Gene family extensions for potent antimicrobial peptides, the arminins, were detected in four Hydra species, with each species possessing a unique composition and expression profile of arminins. For functional analysis, we inoculated arminin-deficient and control polyps with bacterial consortia characteristic for different Hydra species and compared their selective preferences by 454 pyrosequencing of the bacterial microbiota. In contrast to control polyps, arminin-deficient polyps displayed decreased potential to select for bacterial communities resembling their native microbiota. This finding indicates that species-specific antimicrobial peptides shape species-specific bacterial associations. PMID:24003149

Sea lamprey (Petromyzon marinus) parasite-host interactions in the Great Lakes

USGS Publications Warehouse

Bence, James R.; Bergstedt, Roger A.; Christie, Gavin C.; Cochran, Phillip A.; Ebener, Mark P.; Koonce, Joseph F.; Rutter, Michael A.; Swink, William D.

2003-01-01

Prediction of how host mortality responds to efforts to control sea lampreys (Petromyzon marinus) is central to the integrated management strategy for sea lamprey (IMSL) in the Great Lakes. A parasite-host submodel is used as part of this strategy, and this includes a type-2 multi-species functional response, a developmental response, but no numerical response. General patterns of host species and size selection are consistent with the model assumptions, but some observations appear to diverge. For example, some patterns in sea lamprey marking on hosts suggest increases in selectivity for less preferred hosts and lower host survival when preferred hosts are scarce. Nevertheless, many of the IMSL assumptions may be adequate under conditions targeted by fish community objectives. Of great concern is the possibility that the survival of young parasites (parasitic-phase sea lampreys) varies substantially among lakes or over time. Joint analysis of abundance estimates for parasites being produced in streams and returning spawners could address this. Data on sea lamprey marks is a critical source of information on sea lamprey activity and potential effects. Theory connecting observed marks to sea lamprey feeding activity and host mortality is reviewed. Uncertainties regarding healing and attachment times, the probability of hosts surviving attacks, and problems in consistent classification of marks have led to widely divergent estimates of damages caused by sea lamprey. Laboratory and field studies are recommended to provide a firmer linkage between host blood loss, host mortality, and observed marks on surviving hosts, so as to improve estimates of damage.

Grapefruit as a host for the West Indian fruit fly (Diptera: Tephritidae).

PubMed

Mangan, Robert L; Thomas, Donald B; Moreno, Aleena Tarshis; Robacker, David

2011-02-01

The most common hosts for the West Indian fruit fly, Anastrepha obliqua (Macquart) (Diptera: Tephritidae) are fruit in the family Anacardiaceae (mango [Mangifera L.] and mombin [Spondias L.] species). However, similar to many of the tropical fruit flies of major economic importance, this species attacks several other families of crop fruit, including Annonaceae (cherimoya, Annona cherimola Mill.), Myrtaceae (guava, Psidium L.), Oxalidaceae (carambola, Averrhoa carambola L.), Passifloraceae (granadilla, Passiflora quadrangularis Mill.), and Sapotaceae [mamey sapote, Pouteria sapota (Jacq.) H. E. Moore & Steam]. In the family Rutaceae the economically important genus Citrus has been reported and until recently considered a host for this fruit fly. In this study, we reviewed the taxonomy of A. obliqua, tested specific chemicals that may inhibit oviposition, compared egg-to-adult survival of A. obliqua on preferred hosts and on grapefruit (Citrus X paradisi Macfad.), and measured fruit tissue-specific developmental rates of A. obliqua and the known citrus breeding Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae), from egg to pupae. Our literature review shows much confusion concerning the taxonomy of this and related Anastrepha species, including synonymies and confusion with other species. The deterrent effect of the highest concentration of flavonoids for oviposition, although significant, was not absolute. Experiments carried out under laboratory conditions showed 15-40 times greater survival of A. ludens (whose preferred hosts include Rutaceae) on grapefruit compared with A. obliqua for both tree attached and harvested fruit. Experiments of survival of developing stages over time showed that the two species oviposit into different tissues in the fruit, and mortality is much higher for the West Indian fruit fly in the flavedo and albedo of the fruit compared with the Mexican fruit fly.

Sharing of Diverse Mycorrhizal and Root-Endophytic Fungi among Plant Species in an Oak-Dominated Cool–Temperate Forest

PubMed Central

Toju, Hirokazu; Yamamoto, Satoshi; Sato, Hirotoshi; Tanabe, Akifumi S.

2013-01-01

Most terrestrial plants interact with diverse clades of mycorrhizal and root-endophytic fungi in their roots. Through belowground plant–fungal interactions, dominant plants can benefit by interacting with host-specific mutualistic fungi and proliferate in a community based on positive plant–mutualistic fungal feedback. On the other hand, subordinate plant species may persist in the community by sharing other sets (functional groups) of fungal symbionts with each other. Therefore, revealing how diverse clades of root-associated fungi are differentially hosted by dominant and subordinate plant species is essential for understanding plant community structure and dynamics. Based on 454-pyrosequencing, we determined the community composition of root-associated fungi on 36 co-occurring plant species in an oak-dominated forest in northern Japan and statistically evaluated the host preference phenotypes of diverse mycorrhizal and root-endophytic fungi. An analysis of 278 fungal taxa indicated that an ectomycorrhizal basidiomycete fungus in the genus Lactarius and a possibly endophytic ascomycete fungus in the order Helotiales significantly favored the dominant oak (Quercus) species. In contrast, arbuscular mycorrhizal fungi were generally shared among subordinate plant species. Although fungi with host preferences contributed to the compartmentalization of belowground plant–fungal associations, diverse clades of ectomycorrhizal fungi and possible root endophytes were associated not only with the dominant Quercus but also with the remaining plant species. Our findings suggest that dominant-ectomycorrhizal and subordinate plant species can host different subsets of root-associated fungi, and diverse clades of generalist fungi can counterbalance the compartmentalization of plant–fungal associations. Such insights into the overall structure of belowground plant–fungal associations will help us understand the mechanisms that facilitate the coexistence of plant species in natural communities. PMID:24250752

Density-dependent topographical specialization in Gyrodactylus anisopharynx (Monogenoidea, Gyrodactylidae): boosting transmission or evading competition?

PubMed

Pie, Marcio R; Engers, Kerlen B; Boeger, Walter A

2006-06-01

Viviparous gyrodactylids are remarkable monogenoid ectoparasites, not only because of their speciousness, but also due to their unusually wide range of hosts. Although many factors have been proposed to determine the location where gyrodactylids attach to their hosts, little is known about how their preference for specific host body regions changes over the course of infection. In this study, we investigate the dynamics of topographical specialization of the parasite Gyrodactylus anisopharynx on 2 of its natural freshwater fish hosts (Corydoras paleatus and C. ehrhardti), as well as a naïve host (C. schwartzi). We recorded the spatial location of this parasite from the foundation of the infrapopulation to its extinction to assess how topographical specialization is affected by host species, the size and the age of the infrapopulation, and the possibility of transmission among hosts. Our results indicate that topographical specialization is negatively correlated with infrapopulation size and only marginally affected by infrapopulation age. Also, the degree of specialization was different among host species, but seemed unaffected by the possibility of transmission among hosts. Therefore, observed changes in spatial specialization of G. anisopharynx do not appear to represent adaptive responses to maximize their transmission. Rather, mechanisms such as increased competition and/ or local immune responses might cause parasites to occupy less favorable regions of the body of their hosts with increasing density.

Distinct innate immune phagocyte responses to Aspergillus fumigatus conidia and hyphae in zebrafish larvae.

PubMed

Knox, Benjamin P; Deng, Qing; Rood, Mary; Eickhoff, Jens C; Keller, Nancy P; Huttenlocher, Anna

2014-10-01

Aspergillus fumigatus is the most common filamentous fungal pathogen of immunocompromised hosts, resulting in invasive aspergillosis (IA) and high mortality rates. Innate immunity is known to be the predominant host defense against A. fumigatus; however, innate phagocyte responses to A. fumigatus in an intact host and their contributions to host survival remain unclear. Here, we describe a larval zebrafish A. fumigatus infection model amenable to real-time imaging of host-fungal interactions in live animals. Following infection with A. fumigatus, innate phagocyte populations exhibit clear preferences for different fungal morphologies: macrophages rapidly phagocytose conidia and form aggregates around hyphae, while the neutrophil response is dependent upon the presence of hyphae. Depletion of macrophages rendered host larvae susceptible to invasive disease. Moreover, a zebrafish model of human leukocyte adhesion deficiency with impaired neutrophil function also resulted in invasive disease and impaired host survival. In contrast, macrophage-deficient but not neutrophil-deficient larvae exhibited attenuated disease following challenge with a less virulent (ΔlaeA) strain of A. fumigatus, which has defects in secondary metabolite production. Taking these results together, we have established a new vertebrate model for studying innate immune responses to A. fumigatus that reveals distinct roles for neutrophils and macrophages in mediating host defense against IA. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Sensory specificity and speciation: a potential neuronal pathway for host fruit odour discrimination in Rhagoletis pomonella

PubMed Central

Batra, Srishti; Ramaswamy, Sree Subha; Feder, Jeffrey L.

2016-01-01

Behavioural changes in habitat or mate choice can trigger population divergence, leading to speciation. However, little is known about the neurological bases for such changes. Rhagoletis pomonella (Diptera: Tephritidae) is a model for ecological speciation via host plant shifts. Within the past 180 years, Rhagoletis flies infesting hawthorn (Crataegus spp.) shifted to attack domesticated apple (Malus pumila). The two populations differ in their olfactory preferences for apple versus hawthorn fruit. Here, we looked for patterns of sensory organization that may have contributed to this shift by characterizing the morphology, specificity and distribution of olfactory sensory neurons (OSNs) on the antennae of Rhagoletis responding to host fruit and non-host volatiles. Of 28 OSN classes identified, two colocalized OSN pairs were found that specifically responded to the major behavioural attractant and antagonist volatiles for each fly population. A reversal in the response of these OSNs to fruit volatiles, either through a switch in receptor expression between these paired neurons or changes in neuronal projections in the brain, could therefore account for the behavioural difference between apple and hawthorn flies. The finding supports the hypothesis that relatively minor changes in olfactory sensory pathways may contribute to rapid host shifting and divergence in Rhagoletis. PMID:28003447

Bacteriophages infecting Bacteroides as a marker for microbial source tracking.

PubMed

Jofre, Joan; Blanch, Anicet R; Lucena, Francisco; Muniesa, Maite

2014-05-15

Bacteriophages infecting certain strains of Bacteroides are amid the numerous procedures proposed for tracking the source of faecal pollution. These bacteriophages fulfil reasonably well most of the requirements identified as appropriate for a suitable marker of faecal sources. Thus, different host strains are available that detect bacteriophages preferably in water contaminated with faecal wastes corresponding to different animal species. For phages found preferably in human faecal wastes, which are the ones that have been more extensively studied, the amounts of phages found in waters contaminated with human fecal samples is reasonably high; these amounts are invariable through the time; their resistance to natural and anthropogenic stressors is comparable to that of other relatively resistant indicator of faecal pollution such us coliphages; the abundance ratios of somatic coliphages and bacteriophages infecting Bacteroides thetaiotaomicron GA17 are unvarying in recent and aged contamination; and standardised detection methods exist. These methods are easy, cost effective and provide data susceptible of numerical analysis. In contrast, there are some uncertainties regarding their geographical stability, and consequently suitable hosts need to be isolated for different geographical areas. However, a feasible method has been described to isolate suitable hosts in a given geographical area. In summary, phages infecting Bacteroides are a marker of faecal sources that in our opinion merits being included in the "toolbox" for microbial source tracking. However, further research is still needed in order to make clear some uncertainties regarding some of their characteristics and behaviour, to compare their suitability to the one of emerging methods such us targeting Bacteroidetes by qPCR assays; or settling molecular methods for their determination. Copyright © 2014 Elsevier Ltd. All rights reserved.

Choice Defines Value: A Predictive Modeling Competition in Health Preference Research.

PubMed

Jakubczyk, Michał; Craig, Benjamin M; Barra, Mathias; Groothuis-Oudshoorn, Catharina G M; Hartman, John D; Huynh, Elisabeth; Ramos-Goñi, Juan M; Stolk, Elly A; Rand, Kim

2018-02-01

To identify which specifications and approaches to model selection better predict health preferences, the International Academy of Health Preference Research (IAHPR) hosted a predictive modeling competition including 18 teams from around the world. In April 2016, an exploratory survey was fielded: 4074 US respondents completed 20 out of 1560 paired comparisons by choosing between two health descriptions (e.g., longer life span vs. better health). The exploratory data were distributed to all teams. By July, eight teams had submitted their predictions for 1600 additional pairs and described their analytical approach. After these predictions had been posted online, a confirmatory survey was fielded (4148 additional respondents). The victorious team, "Discreetly Charming Econometricians," led by Michał Jakubczyk, achieved the smallest χ 2 , 4391.54 (a predefined criterion). Its primary scientific findings were that different models performed better with different pairs, that the value of life span is not constant proportional, and that logit models have poor predictive validity in health valuation. The results demonstrated the diversity and potential of new analytical approaches in health preference research and highlighted the importance of predictive validity in health valuation. Copyright © 2018 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

Tidal Disruption Events Prefer Unusual Host Galaxies

NASA Astrophysics Data System (ADS)

Arcavi, Iair; French, K. Decker; Zabludoff, Ann I.

2016-06-01

A star passing close to a supermassive black hole (SMBH) can be torn apart in a Tidal Disruption Events (TDE). TDEs that are accompanied by observable flares are now being discovered in transient surveys and are revealing the presence and the properties of otherwise-quiescent SMBHs. Recently, it was discovered that TDEs show a strong preference for rare post-starburst galaxies, (i.e. galaxies that have undergone intense star formation but are no longer forming stars today). We quantify this preference and find that TDEs are approximately 30-200 times more likely to occur in post-starburst hosts (compared to the general SDSS galaxy population), with the enhancement factor depending on the star formation history of the galaxy. This surprising host-galaxy preference connects the until-now disparate TDE subclasses of UV/optical-dominated TDEs and X-ray-dominated TDEs, and serves as the basis for TDE-targeted transient surveys. Post-starburst galaxies may be post-mergers, with binary SMBH systems that are still spiraling in. Such systems could enhance the TDE rate, but it is not yet clear if models can quantitatively reproduce the observed enhancement. Alternative explanations for enhanced TDE rate in post-starbursts include non-spherical post-merger central potentials and enhanced rates of giant stars.

Communicating Uncertainty in Volcanic Ash Forecasts: Decision-Making and Information Preferences

NASA Astrophysics Data System (ADS)

Mulder, Kelsey; Black, Alison; Charlton-Perez, Andrew; McCloy, Rachel; Lickiss, Matthew

2016-04-01

The Robust Assessment and Communication of Environmental Risk (RACER) consortium, an interdisciplinary research team focusing on communication of uncertainty with respect to natural hazards, hosted a Volcanic Ash Workshop to discuss issues related to volcanic ash forecasting, especially forecast uncertainty. Part of the workshop was a decision game in which participants including forecasters, academics, and members of the Aviation Industry were given hypothetical volcanic ash concentration forecasts and asked whether they would approve a given flight path. The uncertainty information was presented in different formats including hazard maps, line graphs, and percent probabilities. Results from the decision game will be presented with a focus on information preferences, understanding of the forecasts, and whether different formats of the same volcanic ash forecast resulted in different flight decisions. Implications of this research will help the design and presentation of volcanic ash plume decision tools and can also help advise design of other natural hazard information.

A RECENT HOST RANGE EXPANSION IN JUNONIA COENIA HÜBNER (NYMPHALIDAE): OVIPOSITION PREFERENCE, SURVIVAL, GROWTH, AND CHEMICAL DEFENSE.

PubMed

Camara, Mark D

1997-06-01

This paper reports on an investigation of two populations of Junonia coenia, the buckeye butterfly, one that feeds on the species' typical host plant (Plantago lanceolata) and one that utilizes a novel host plant (Kickxia elatine). I examined these populations for local adaptive responses in terms of oviposition behavior, growth, and chemical defense, on both P. lanceolata and K. elatine. In addition, I examined the genetic architecture underlying these traits using a full-sib quantitative genetic analysis. I found that a significant majority of females prefer the host plant species found at their collection sites in oviposition tests, but that there is no evidence that they are locally adapted in growth performance, as measured by fifth-instar and pupal weights and development times. Neither are there correlations between oviposition preferences of females and the growth performance or levels of chemical defense of their offspring. The two populations studied do, however, show specialization in terms of the levels of chemical defense they sequester from their host plants. I argue that these results indicate that natural enemies are the normal barriers to host range expansion in this oligophagous herbivore because a breakdown in those barriers results in genetic changes that enhance resistance to predation. This is despite the fact that adaptive responses in physiology are unlikely to be limited by a lack of genetic variability; the genetic architecture among traits would be conducive to specialization in growth performance; and there are costs to chemical defense in this species. All these conditions would tend to argue that J. coenia harbors considerable potential for coevolutionary interactions with its chemically defended hosts, but this potential is not realized, probably because natural selection on diet breadth by natural enemies is much stronger than selection from host plants in this system. © 1997 The Society for the Study of Evolution.

Pre-pupation behaviour of the aphid parasitoid Aphidius ervi (Haliday) and its consequences for pre-imaginal learning

NASA Astrophysics Data System (ADS)

Gutiérrez-Ibáñez, Cristián; Villagra, Cristian A.; Niemeyer, Hermann M.

2007-07-01

Olfactory learning may occur at different stages of insect ontogeny. In parasitoid wasps, it has been mostly shown at adult emergence, whilst it remains controversial at pre-imaginal stages. We followed larval growth of the parasitoid wasp, Aphidius ervi Haliday, inside the host aphid, Acyrthosiphom pisum Harris, and characterised in detail the behaviour of third instar larvae. We found that just before cocoon spinning begins, the third instar larva bites a hole through the ventral side of the mummified aphid exoskeleton. We then evaluated whether this period of exposure to the external environment represented a sensitive stage for olfactory learning. In our first experiment, the third instar larvae were allowed to spin their cocoon on the host plant ( Vicia faba L.) surface or on a plastic plate covering the portion of the host plant exposed to the ventral opening. Recently emerged adults of the first group showed a preference for plant volatiles in a glass Y-olfactometer, whereas no preference was found in adults of the second group. In a second experiment, during the period in which the aphid carcass remains open or is being sealed by cocoon spinning, third instar larvae were exposed for 24 h to either vanilla odours or water vapours as control. In this experiment, half of the parasitoid larvae were later excised from the mummy to avoid further exposure to vanilla. Adult parasitoids exposed to vanilla during the larval ventral opening of the mummy showed a significant preference for vanilla odours in the olfactometer, regardless of excision from the mummy. The larval behaviour described and the results of the manipulations performed are discussed as evidences for the acquisition of olfactory memory during the larval stage and its persistence through metamorphosis.

An olfactory receptor from Apolygus lucorum (Meyer-Dur) mainly tuned to volatiles from flowering host plants.

PubMed

Yan, Shu-Wei; Zhang, Jin; Liu, Yang; Li, Guo-Qing; Wang, Gui-Rong

2015-08-01

Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is one of the most serious agricultural pests, feeding on a wide range of cultivated plants, including cotton, cereals and vegetables in the north of China. This insect can frequently switch between habitats and host plants over seasons and prefer plants in bloom. A. lucorum relies heavily on olfaction to locate its host plants finely discriminating different plant volatiles in the environment. Despite its economical importance, research on the olfactory system of this species has been so far very limited. In this study, we have identified and characterized an olfactory receptor which is sensitively tuned to (Z)-3-Hexenyl acetate and several flowering compounds. Besides being present in the bouquet of some flowers, these compounds are produced by plants that have suffered attacks and are supposed to act as chemical messengers between plants. This OR may play an important role in the selection of host plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

Spatial and host-associated variation in prevalence and population density of wheat curl mite (Aceria tosichella) cryptic genotypes in agricultural landscapes

USDA-ARS?s Scientific Manuscript database

The wheat curl mite (WCM), Aceria tosichella Keifer, is a major pest of cereals worldwide that also comprises a complex of at least 16 genetic lineages with divergent physiological traits, including host preference and specificity. The goal of this study was to test the extent to which host-plant sp...

Diversity and distribution of epiphytic bromeliads in a Brazilian subtropical mangrove.

PubMed

Sousa, Mariana M DE; Colpo, Karine D

2017-01-01

It is not unusual to find epiphytic bromeliads in mangroves, but most studies on mangrove vegetation do not record their presence. This study aimed to evaluate the diversity and distribution of epiphytic bromeliads in a subtropical mangrove. The richness, abundance and life form (atmospheric and tank) of bromeliads were recorded and compared among host tree species and waterline proximity. The effects of diameter and height of host trees on the abundance of bromeliads were also assessed. The mangrove was composed of Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle. We recorded seven bromeliad species of the genera Tillandsia and Vriesea. The waterline proximity did not affect the abundance or diversity of bromeliads, but atmospheric forms were predominant near the waterline, whereas tank bromeliads were more frequent in the interior of the mangrove. The three mangrove species hosted bromeliads, but L. racemosa was the preferred host. The species composition showed that the distribution of bromeliads is more related to the host species than to the distance from the waterline. Bromeliad abundance increased with tree size. Bromeliads can be biological indicators of ecosystem health; therefore, inventories and host tree preferences are necessary knowledge for an adequate management of sensitive ecosystems as mangroves.

Agriculture sows pests: how crop domestication, host shifts, and agricultural intensification can create insect pests from herbivores.

PubMed

Bernal, Julio S; Medina, Raul F

2018-04-01

We argue that agriculture as practiced creates pests. We use three examples (Corn leafhopper, Dalbulus maidis; Western corn rootworm, Diabrotica virgifera virgifera; Cotton fleahopper, Pseudatomoscelis seriatus) to illustrate: firstly, how since its origins, agriculture has proven conducive to transforming selected herbivores into pests, particularly through crop domestication and spread, and agricultural intensification, and; secondly, that the herbivores that became pests were among those hosted by crop wild relatives or associates, and were pre-adapted either as whole species or component subpopulations. Two of our examples, Corn leafhopper and Western corn rootworm, illustrate how following a host shift to a domesticated host, emergent pests 'hopped' onto crops and rode expansion waves to spread far beyond the geographic ranges of their wild hosts. Western corn rootworm exemplifies how an herbivore-tolerant crop was left vulnerable when it was bred for yield and protected with insecticides. Cotton fleahopper illustrates how removing preferred wild host plants from landscapes and replacing them with crops, allows herbivores with flexible host preferences to reach pest-level populations. We conclude by arguing that in the new geological epoch we face, the Anthropocene, we can improve agriculture by looking to our past to identify and avoid missteps of early and recent farmers. Copyright © 2018 Elsevier Inc. All rights reserved.

Mountain Pine Beetle Host Selection Between Lodgepole and Ponderosa Pines in the Southern Rocky Mountains.

PubMed

West, Daniel R; Briggs, Jennifer S; Jacobi, William R; Negrón, José F

2016-02-01

Recent evidence of range expansion and host transition by mountain pine beetle (Dendroctonus ponderosae Hopkins; MPB) has suggested that MPB may not primarily breed in their natal host, but will switch hosts to an alternate tree species. As MPB populations expanded in lodgepole pine forests in the southern Rocky Mountains, we investigated the potential for movement into adjacent ponderosa pine forests. We conducted field and laboratory experiments to evaluate four aspects of MPB population dynamics and host selection behavior in the two hosts: emergence timing, sex ratios, host choice, and reproductive success. We found that peak MPB emergence from both hosts occurred simultaneously between late July and early August, and the sex ratio of emerging beetles did not differ between hosts. In two direct tests of MPB host selection, we identified a strong preference by MPB for ponderosa versus lodgepole pine. At field sites, we captured naturally emerging beetles from both natal hosts in choice arenas containing logs of both species. In the laboratory, we offered sections of bark and phloem from both species to individual insects in bioassays. In both tests, insects infested ponderosa over lodgepole pine at a ratio of almost 2:1, regardless of natal host species. Reproductive success (offspring/female) was similar in colonized logs of both hosts. Overall, our findings suggest that MPB may exhibit equally high rates of infestation and fecundity in an alternate host under favorable conditions. © 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.

Delimiting cryptic pathogen species causing apple Valsa canker with multilocus data

PubMed Central

Wang, Xuli; Zang, Rui; Yin, Zhiyuan; Kang, Zhensheng; Huang, Lili

2014-01-01

Fungal diseases are posing tremendous threats to global economy and food safety. Among them, Valsa canker, caused by fungi of Valsa and their Cytospora anamorphs, has been a serious threat to fruit and forest trees and is one of the most destructive diseases of apple in East Asia, particularly. Accurate and robust delimitation of pathogen species is not only essential for the development of effective disease control programs, but also will advance our understanding of the emergence of plant diseases. However, species delimitation is especially difficult in Valsa because of the high variability of morphological traits and in many cases the lack of the teleomorph. In this study, we delimitated species boundary for pathogens causing apple Valsa canker with a multifaceted approach. Based on three independent loci, the internal transcribed spacer (ITS), β-tubulin (Btu), and translation elongation factor-1 alpha (EF1α), we inferred gene trees with both maximum likelihood and Bayesian methods, estimated species tree with Bayesian multispecies coalescent approaches, and validated species tree with Bayesian species delimitation. Through divergence time estimation and ancestral host reconstruction, we tested the possible underlying mechanisms for fungal speciation and host-range change. Our results proved that two varieties of the former morphological species V. mali represented two distinct species, V. mali and V. pyri, which diverged about 5 million years ago, much later than the divergence of their preferred hosts, excluding a scenario of fungi–host co-speciation. The marked different thermal preferences and contrasting pathogenicity in cross-inoculation suggest ecological divergences between the two species. Apple was the most likely ancestral host for both V. mali and V. pyri. Host-range expansion led to the occurrence of V. pyri on both pear and apple. Our results also represent an example in which ITS data might underestimate species diversity. PMID:24834333

Recombinant hosts suitable for simultaneous saccharification and fermentation

DOEpatents

Ingram, Lonnie O'Neal; Zhou, Shengde

2007-06-05

The invention provides recombinant host cells containing at least one heterologous polynucleotide encoding a polysaccharase under the transcriptional control of a surrogate promoter capable of increasing the expression of the polysaccharase. In addition, the invention further provides such hosts with genes encoding secretory protein/s to facilitate the secretion of the expressed polysaccharase. Preferred hosts of the invention are ethanologenic and capable of carrying out simultaneous saccharification fermentation resulting in the production of ethanol from complex cellulose substrates.

Divergent host preferences of above- and below-ground Culex pipiens mosquitoes and their hybrid offspring.

PubMed

Fritz, M L; Walker, E D; Miller, J R; Severson, D W; Dworkin, I

2015-06-01

Culex pipiens form pipiens and Cx. pipiens form molestus (Diptera: Culicidae) belong to a cosmopolitan taxonomic group known as the Pipiens Assemblage. Hybridization between these forms is thought to contribute to human transmission of West Nile virus (WNV) in North America. Complementary choice and no-choice landing assays were developed to examine host acceptance by North American Cx. pipiens in the laboratory. Populations collected from above- and below-ground sites in suburban Chicago were identified as forms pipiens and molestus using a polymerase chain reaction-based assay. Avian and human host acceptance was then quantified for the two populations, as well as for their hybrid and backcross offspring. No-choice tests were used to demonstrate that both the pipiens and molestus forms were capable of feeding on human and avian hosts. Choice tests were used to demonstrate that form pipiens females were strongly avian-seeking; an individual's probability of accepting the chick host was 85%. Form molestus females were more likely to accept the human host (87%). Rates of host acceptance by F1 and backcross progeny were intermediate to those of their parents. The results suggest that host preferences in Cx. pipiens are genetically determined, and that ongoing hybridization between above- and below-ground populations is an important contributor to epizootic transmission of WNV in North America. © 2015 The Royal Entomological Society.

What does heat tell a mosquito? Characterization of the orientation behaviour of Aedes aegypti towards heat sources.

PubMed

Zermoglio, Paula F; Robuchon, Eddy; Leonardi, María Soledad; Chandre, Fabrice; Lazzari, Claudio R

2017-07-01

The use of heat as a cue for the orientation of haematophagous insects towards hot-blooded hosts has been acknowledged for many decades. In mosquitoes, thermoreception has been studied at the molecular, physiological and behavioural levels, and the response to heat has been evaluated in multimodal contexts. However, a direct characterization of how these insects evaluate thermal sources is still lacking. In this study we characterize Aedes aegypti thermal orientation using a simple dual choice paradigm, providing direct evidence on how different attributes of heat sources affect their choice. We found that female mosquitoes, but not males, are able to discriminate among heat sources that are at ambient, host-range and deleterious temperatures when no other stimuli are present, eliciting a positive response towards host-range and an avoidance response towards deleterious temperatures. We also tested the preference of females according to the size and position of the sources. We found that females do not discriminate between heat sources of different sizes, but actively orientate towards closer sources at host temperature. Furthermore, we show that females cannot use IR radiation as an orientation cue. Orientation towards a host involves the integration of cues of different nature in distinct phases of the orientation. Although such integration might be decisive for successful encounter of the host, we show that heat alone is sufficient to elicit orientation behaviour. We discuss the performance of mosquitoes' thermal behaviour compared to other blood-sucking insects. Copyright © 2017 Elsevier Ltd. All rights reserved.

Can We Disrupt the Sensing of Honey Bees by the Bee Parasite Varroa destructor?

PubMed Central

Eliash, Nurit; Singh, Nitin Kumar; Kamer, Yosef; Pinnelli, Govardhana Reddy; Plettner, Erika; Soroker, Victoria

2014-01-01

Background The ectoparasitic mite, Varroa destructor, is considered to be one of the most significant threats to apiculture around the world. Chemical cues are known to play a significant role in the host-finding behavior of Varroa. The mites distinguish between bees from different task groups, and prefer nurses over foragers. We examined the possibility of disrupting the Varroa – honey bee interaction by targeting the mite's olfactory system. In particular, we examined the effect of volatile compounds, ethers of cis 5-(2′-hydroxyethyl) cyclopent-2-en-1-ol or of dihydroquinone, resorcinol or catechol. We tested the effect of these compounds on the Varroa chemosensory organ by electrophysiology and on behavior in a choice bioassay. The electrophysiological studies were conducted on the isolated foreleg. In the behavioral bioassay, the mite's preference between a nurse and a forager bee was evaluated. Principal findings We found that in the presence of some compounds, the response of the Varroa chemosensory organ to honey bee headspace volatiles significantly decreased. This effect was dose dependent and, for some of the compounds, long lasting (>1 min). Furthermore, disruption of the Varroa volatile detection was accompanied by a reversal of the mite's preference from a nurse to a forager bee. Long-term inhibition of the electrophysiological responses of mites to the tested compounds was a good predictor for an alteration in the mite's host preference. Conclusions These data indicate the potential of the selected compounds to disrupt the Varroa - honey bee associations, thus opening new avenues for Varroa control. PMID:25226388

Differential expression of chemosensory-protein genes in midguts in response to diet of Spodoptera litura.

PubMed

Yi, Xin; Qi, Jiangwei; Zhou, Xiaofan; Hu, Mei Ying; Zhong, Guo Hua

2017-03-22

While it has been well characterized that chemosensory receptors in guts of mammals have great influence on food preference, much remains elusive in insects. Insect chemosensory proteins (CSPs) are soluble proteins that could deliver chemicals to olfactory and gustatory receptors. Recent studies have identified a number of CSPs expressed in midgut in Lepidoptera insects, which started to reveal their roles in chemical recognition and stimulating appetite in midgut. In this study, we examined expression patterns in midgut of 21 Spodoptera litura CSPs (SlitCSPs) characterized from a previously reported transcriptome, and three CSPs were identified to be expressed highly in midgut. The orthologous relationships between midgut expressed CSPs in S. litura and those in Bombyx mori and Plutella xylostella also suggest a conserved pattern of CSP expression in midgut. We further demonstrated that the expression of midgut-CSPs may change in response to different host plants, and SlitCSPs could bind typical chemicals from host plant in vitro. Overall, our results suggested midgut expressed SlitCSPs may have functional roles, likely contributing to specialization and adaption to different ecosystems. Better knowledge of this critical component of the chemsensation signaling pathways in midguts may improve our understanding of food preference processes in a new perspective.

Evolutionary history of aphid-plant associations and their role in aphid diversification.

PubMed

Peccoud, Jean; Simon, Jean-Christophe; von Dohlen, Carol; Coeur d'acier, Armelle; Plantegenest, Manuel; Vanlerberghe-Masutti, Flavie; Jousselin, Emmanuelle

2010-01-01

Aphids are intimately linked with their host plants that constitute their only food resource and habitat, and thus impose considerable selective pressure on their evolution. It is therefore commonly assumed that host plants have greatly influenced the diversification of aphids. Here, we review what is known about the role of host plant association on aphid speciation by examining both macroevolutionary and population-level studies. Phylogenetic studies conducted at different taxonomic levels show that, as in many phytophagous insect groups, the radiation of angiosperms has probably favoured the major Tertiary diversification of aphids. These studies also highlight many aphid lineages constrained to sets of related host plants, suggesting strong evolutionary commitment in aphids' host plant choice, but they fail to document cospeciation events between aphid and host lineages. Instead, phylogenies of several aphid genera reveal that divergence events are often accompanied by host shifts, and suggest, without constituting a formal demonstration, that aphid speciation could be a consequence of adaptation to new hosts. Experimental and field studies below the species level support reproductive isolation between host races as partly due to divergent selection by their host plants. Selected traits are mainly feeding performances and life cycle adaptations to plant phenology. Combined with behavioural preference for favourable host species, these divergent adaptations can induce pre- and post-zygotic barriers between host-specialized aphid populations. However, the hypothesis of host-driven speciation is seldom tested formally and must be weighed against overlooked explanations involving geographic isolation and non-ecological reproductive barriers in the process of speciation. Copyright 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Learning and memory in disease vector insects

PubMed Central

Vinauger, Clément; Lahondère, Chloé; Cohuet, Anna; Lazzari, Claudio R.; Riffell, Jeffrey A.

2016-01-01

Learning and memory plays an important role in host preference and parasite transmission by disease vector insects. Historically there has been a dearth of standardized protocols that permit testing their learning abilities, thus limiting discussion on the potential epidemiological consequences of learning and memory to a largely speculative extent. However, with increasing evidence that individual experience and associative learning can affect processes such as oviposition site selection and host preference, it is timely to review the recently acquired knowledge, identify research gaps and discuss the implication of learning in disease vector insects in perspective with control strategies. PMID:27450224

Evaluation of grapevine as a host for the glassy-winged sharpshooter

USDA-ARS?s Scientific Manuscript database

Grapevine was evaluated as a feeding and oviposition host for the glassy-winged sharpshooter. Two sets of experiments were conducted. The first set compared performance and preference of glassy-winged sharpshooter females for grapevine (cv. Chardonnay) versus cowpea (Vigna unguiculata cultivar black...

32 CFR 562.5 - Policies.

Code of Federal Regulations, 2010 CFR

2010-07-01

... workable program. The right of orderly campus dissent is recognized. However, anti-ROTC activities which... accomplish program objectives of the host institution. Activities which are part of the host school's... that each cadet realizes the importance of choice of branch preferences and what is involved in making...

Nonvolatile chemical cues affect host-plant ranking by gravid Polygonia c-album females.

PubMed

Mozūraitis, Raimondas; Murtazina, Rushana; Nylin, Sören; Borg-Karlson, Anna-Karin

2012-01-01

In a multiple-choice test, the preference of egg-laying Polygonia c-album (comma butterfly) females was studied for oviposition on plants bearing surrogate leaves treated with crude methanol extracts obtained from leaves of seven host-plant species: Humulus lupulus, Urtica dioica, Ulmus glabra, Salix caprea, Ribes nigrum, Corylus avellana, and Betula pubescens. The ranking order of surrogate leaves treated with host-plant extracts corresponded well to that reported on natural foliage, except R. nigrum. Thus, host-plant choice in P. c-album seems to be highly dependent on chemical cues. Moreover, after two subsequent fractionations using reversed-phase chromatography the nonvolatile chemical cues residing in the most polar water-soluble fractions evidently provided sufficient information for egg-laying females to discriminate and rank between the samples of more and less preferred plants, since the ranking in these assays was similar to that for natural foliage or whole methanol extracts, while the physical traits of the surrogate leaves remained uniform.

Parasitoids select plants more heavily infested with their caterpillar hosts: a new approach to aid interpretation of plant headspace volatiles

PubMed Central

Girling, Robbie D.; Stewart-Jones, Alex; Dherbecourt, Julie; Staley, Joanna T.; Wright, Denis J.; Poppy, Guy M.

2011-01-01

Plants produce volatile organic compounds (VOCs) in response to herbivore attack, and these VOCs can be used by parasitoids of the herbivore as host location cues. We investigated the behavioural responses of the parasitoid Cotesia vestalis to VOCs from a plant–herbivore complex consisting of cabbage plants (Brassica oleracea) and the parasitoids host caterpillar, Plutella xylostella. A Y-tube olfactometer was used to compare the parasitoids' responses to VOCs produced as a result of different levels of attack by the caterpillar and equivalent levels of mechanical damage. Headspace VOC production by these plant treatments was examined using gas chromatography–mass spectrometry. Cotesia vestalis were able to exploit quantitative and qualitative differences in volatile emissions, from the plant–herbivore complex, produced as a result of different numbers of herbivores feeding. Cotesia vestalis showed a preference for plants with more herbivores and herbivore damage, but did not distinguish between different levels of mechanical damage. Volatile profiles of plants with different levels of herbivores/herbivore damage could also be separated by canonical discriminant analyses. Analyses revealed a number of compounds whose emission increased significantly with herbivore load, and these VOCs may be particularly good indicators of herbivore number, as the parasitoid processes cues from its external environment. PMID:21270031

Species difference in ANP32A underlies influenza A virus polymerase host restriction

PubMed Central

Long, Jason S.; Giotis, Efstathios S.; Moncorgé, Olivier; Frise, Rebecca; Mistry, Bhakti; James, Joe; Morisson, Mireille; Iqbal, Munir; Vignal, Alain; Skinner, Michael A.; Barclay, Wendy S.

2015-01-01

Influenza pandemics occur unpredictably when zoonotic influenza viruses with novel antigenicity acquire the ability to transmit amongst humans 1. Incompatibilities between avian virus components and the human host limit host range breaches. Barriers include receptor preference, virion stability and poor activity of the avian virus RNA-dependent RNA polymerase in human cells 2. Mutants of the heterotrimeric viral polymerase components, particularly PB2 protein, are selected during mammalian adaptation, but their mode of action is unknown 3–6. We show that a species-specific difference in host protein ANP32A accounts for the suboptimal function of avian virus polymerase in mammalian cells. Avian ANP32A possesses an additional 33 amino acids between the LRR and LCAR domains. In mammalian cells, avian ANP32A rescued the suboptimal function of avian virus polymerase to levels similar to mammalian adapted polymerase. Deletion of the avian-specific sequence from chicken ANP32A abrogated this activity whereas its insertion into human ANP32A, or closely related ANP32B, supported avian virus polymerase function. Substitutions, such as PB2 E627K, rapidly selected upon infection of humans with avian H5N1 or H7N9 influenza viruses, adapt the viral polymerase for the shorter mammalian ANP32A. Thus ANP32A represents an essential host partner co-opted to support influenza virus replication and is a candidate host target for novel antivirals. PMID:26738596

Occurrence and distribution of Giardia species in wild rodents in Germany.

PubMed

Helmy, Yosra A; Spierling, Nastasja G; Schmidt, Sabrina; Rosenfeld, Ulrike M; Reil, Daniela; Imholt, Christian; Jacob, Jens; Ulrich, Rainer G; Aebischer, Toni; Klotz, Christian

2018-03-27

Giardiasis is an important gastrointestinal parasitic disease in humans and other mammals caused by the protozoan Giardia duodenalis. This species complex is represented by genetically distinct groups (assemblages A-H) with varying zoonotic potential and host preferences. Wild rodents can harbor potentially zoonotic assemblages A and B, and the rodent-specific assemblage G. Other Giardia spp. found in these animals are Giardia muris and Giardia microti. For the latter, only limited information on genetic typing is available. It has been speculated that wild rodents might represent an important reservoir for parasites causing human giardiasis. The aim of this study was to investigate the occurrence and distribution of Giardia spp. and assemblage types in wild rodents from different study sites in Germany. Screening of 577 wild rodents of the genera Apodemus, Microtus and Myodes, sampled at eleven study sites in Germany, revealed a high overall Giardia prevalence. Giardia species determination at the SSU rDNA gene locus revealed that Apodemus mice, depending on species, were predominantly infected with one of two distinct G. muris sequence types. Giardia microti was the predominant parasite species found in voles of the genera Microtus and Myodes. Only a few animals were positive for potentially zoonotic G. duodenalis. Subtyping at the beta-giardin (bg) and glutamine dehydrogenase (gdh) genes strongly supported the existence of different phylogenetic subgroups of G. microti that are preferentially harbored by distinct host species. The present study highlights the preference of G. muris for Apodemus, and G. microti for Microtus and Myodes hosts and argues for a very low prevalence of zoonotic G. duodenalis assemblages in wild rodents in Germany. It also provides evidence that G. muris and G. microti subdivide into several phylogenetically distinguishable subgroups, each of which appears to be preferentially harbored by species of a particular rodent host genus. Finally, the study expands the database of sequences relevant for sequence typing of G. muris and G. microti isolates which will greatly help future analyses of these parasites' population structure.

Host Ecology Rather Than Host Phylogeny Drives Amphibian Skin Microbial Community Structure in the Biodiversity Hotspot of Madagascar

PubMed Central

Bletz, Molly C.; Archer, Holly; Harris, Reid N.; McKenzie, Valerie J.; Rabemananjara, Falitiana C. E.; Rakotoarison, Andolalao; Vences, Miguel

2017-01-01

Host-associated microbiotas of vertebrates are diverse and complex communities that contribute to host health. In particular, for amphibians, cutaneous microbial communities likely play a significant role in pathogen defense; however, our ecological understanding of these communities is still in its infancy. Here, we take advantage of the fully endemic and locally species-rich amphibian fauna of Madagascar to investigate the factors structuring amphibian skin microbiota on a large scale. Using amplicon-based sequencing, we evaluate how multiple host species traits and site factors affect host bacterial diversity and community structure. Madagascar is home to over 400 native frog species, all of which are endemic to the island; more than 100 different species are known to occur in sympatry within multiple rainforest sites. We intensively sampled frog skin bacterial communities, from over 800 amphibians from 89 species across 30 sites in Madagascar during three field visits, and found that skin bacterial communities differed strongly from those of the surrounding environment. Richness of bacterial operational taxonomic units (OTUs) and phylogenetic diversity differed among host ecomorphs, with arboreal frogs exhibiting lower richness and diversity than terrestrial and aquatic frogs. Host ecomorphology was the strongest factor influencing microbial community structure, with host phylogeny and site parameters (latitude and elevation) explaining less but significant portions of the observed variation. Correlation analysis and topological congruency analyses revealed little to no phylosymbiosis for amphibian skin microbiota. Despite the observed geographic variation and low phylosymbiosis, we found particular OTUs that were differentially abundant between particular ecomorphs. For example, the genus Pigmentiphaga (Alcaligenaceae) was significantly enriched on arboreal frogs, Methylotenera (Methylophilaceae) was enriched on aquatic frogs, and Agrobacterium (Rhizobiaceae) was enriched on terrestrial frogs. The presence of shared bacterial OTUs across geographic regions for selected host genera suggests the presence of core microbial communities which in Madagascar, might be driven more strongly by a species’ preference for specific microhabitats than by the physical, physiological or biochemical properties of their skin. These results corroborate that both host and environmental factors are driving community assembly of amphibian cutaneous microbial communities, and provide an improved foundation for elucidating their role in disease resistance. PMID:28861051

Exploring the bacterial gut microbiota of supralittoral talitrid amphipods.

PubMed

Abdelrhman, Khaled F A; Bacci, Giovanni; Marras, Barbara; Nistri, Annamaria; Schintu, Marco; Ugolini, Alberto; Mengoni, Alessio

2017-01-01

Talitrid amphipods (sandhoppers and beach fleas) are typical of the supralittoral zone. They are known to thrive on stranded materials, including detrital marine angiosperms and macroalgae, as well as occasional dead animals. In this work, the gut microbiota of five species of talitrid amphipods (Talitrus saltator, Talorchestia ugolinii, Sardorchestia pelecaniformis, Orchestia montagui and Orchestia stephenseni) collected in Sardinia (Italy) has been investigated through: i) metabarcoding analysis of the amplified 16S rRNA V4 region; and ii) quantification of family 48 glycosyl hydrolase genes (GHF48), involved in cellulose degradation. Results indicate that, though talitrid gut biodiversity is not directly related to taxon or sampling locality, the animals' digestive tracts may host species-specific bacterial communities. In particular, gut microbiota of O. montagui, an inhabitant of Posidonia banquettes and macro-algae mat, showed the greatest differences in taxonomic composition and the highest proportion of GHF48 genes with respect to 16S rRNA genes. These results suggest that the different talitrid species may host species-specific bacterial communities whose function could partially reflect the different microhabitats and food preferences of their host. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

A retrospective analysis of pollen host plant use by stable and declining bumble bee species.

PubMed

Kleijn, David; Raemakers, Ivo

2008-07-01

Understanding population declines has been the objective of a wide range of ecological studies. When species have become rare such studies are complicated because particular behavior or life history traits may be the cause but also the result of the decline of a species. We approached this problem by studying species' characteristics on specimens that were collected before the onset of their decline and preserved in natural history museums. In northwestern Europe, some bumble bee species declined dramatically during the 20th century whereas other, ecologically similar, species maintained stable populations. A long-standing debate focuses on whether this is caused by declining species having stricter host plant preferences. We compared the composition of pollen loads of five bumble bee species with stable populations and five with declining populations using museum specimens collected before 1950 in Belgium, England, and The Netherlands. Prior to 1950, the number of plant taxa in pollen loads of declining species was almost one-third lower than that in stable species even though individuals of stable and declining species generally originated from the same areas. There were no systematic differences in the composition of pollen loads between stable and declining species, but the plant taxa preferred by declining species before 1950 had experienced a stronger decline in the 20th century than those preferred by stable species. In 2004 and 2005, we surveyed the areas where bumble bees had been caught in the past and compared the composition of past and present pollen loads of the stable, but not of the by now locally extinct declining species. The number of collected pollen taxa was similar, but the composition differed significantly between the two periods. Differences in composition reflected the major changes in land use in northwestern Europe but also the spread of the invasive plant species Impatiens glandulifera. The main question now is why declining species apparently were not able to switch to less preferred food plants when stable species were. This study shows that natural history collections can play an important role in improving our understanding of the ecological mechanisms driving species population change.

Host Selection Behavior and the Fecundity of Plutella xylostella (Lepidoptera: Plutellidae) on Multiple Host Plants

PubMed Central

Huang, Bin; Shi, Zhanghong; Hou, Youming

2014-01-01

Abstract Insect herbivores often have higher densities on host plants grown in monocultures than those in diverse environments. The underlying mechanisms are thought to be that polyphagous insects have difficulty in selecting food or oviposition sites when multiple host plants exist. However, this hypothesis needs to be extensively investigated. Our field experiments revealed that the population of the diamondback moths, Plutella xylostella (L.) (Lepidoptera: Plutellidae), significantly decreased in a mixed cropping field compared with a monoculture. To determine the reasons for the reduction in population in the mixed cropping field, the takeoff behavior and fecundity of females in no-choice and free-choice laboratory environments were compared by video recordings of host selection by P. xylostella . Adults displayed a significantly higher takeoff frequency in free-choice environments than those in no-choice treatments and preferred landing on Brassica campestris (L.) or Brassica juncea (Coss) plants in contrast with Brassica oleracea (L.). Female adults in the free-choice environment also laid fewer eggs compared with the monoculture. Olfaction experiments demonstrated orientation by P. xylostella to host volatiles when presented with a choice between plant odors and clean air, but females showed no preference when odors from three Brassicaceae species were presented simultaneously. We conclude that mixed cropping alters the host-finding behavior of P. xylostella resulting in reduced oviposition. PMID:25527573

Biotic and abiotic factors affect green ash volatile production and emerald ash borer adult feeding preference.

PubMed

Chen, Yigen; Poland, Therese M

2009-12-01

The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is an exotic woodborer first detected in 2002 in Michigan and Ontario and is threatening the ash resource in North America. We examined the effects of light exposure and girdling on green ash (Fraxinus pennsylvanica Marsh) volatile production, and effects of light exposure, girdling, and leaf age on emerald ash borer adult feeding preferences and phototaxis. Green ash seedlings grown under higher light exposure had lower amounts of three individual volatile compounds, (Z)-3-hexenol, (E)-beta-ocimene, and (Z,E)-alpha-farnesene, as well as the total amount of six detected volatile compounds. Girdling did not affect the levels of these volatiles. Emerald ash borer females preferred mature leaves, leaves from girdled trees, and leaves grown in the sun over young leaves, leaves from nongirdled trees, and leaves grown in the shade, respectively. These emerald ash borer preferences were most likely because of physical, nutritional, or biochemical changes in leaves in response to the different treatments. Emerald ash borer females and males showed positive phototaxis in laboratory arenas, a response consistent with emerald ash borer preference for host trees growing in sunlight.

Mountain pine beetle-caused mortality over eight years in two pine hosts in mixed-conifer stands of the southern Rocky Mountains

Treesearch

Daniel R. West; Jennifer S. Briggs; William R. Jacobi; Jose F. Negron

2014-01-01

Eruptive mountain pine beetle (Dendroctonus ponderosae, MPB) populations have caused widespread mortality of pines throughout western North America since the late 1990s. Early work by A.D. Hopkins suggested that when alternate host species are available, MPB will prefer to breed in the host to which it has become adapted. In Colorado, epidemic MPB populations that...

Mismatch between herbivore behavior and demographics contributes to scale-dependence of host susceptibility in two pine species

USGS Publications Warehouse

Ylioja, T.; Slone, D.H.; Ayres, M.P.

2005-01-01

The impacts on forests of tree-killing bark beetles can depend on the species composition of potential host trees. Host susceptibility might be an intrinsic property of tree species, or it might depend on spatial patterning of alternative host species. We compared the susceptibility of loblolly pine (Pinus taeda) and Virginia pine (P. virginiana) to southern pine beetle (Dendroctonus frontalis) at two hierarchical levels of geographic scale: within beetle infestations in heterospecific stands (extent ranging from 0.28 to 0.65 ha), and across a forest landscape (extent 72,500 ha) that was dominated by monospecific stands. In the former, beetles preferentially attacked Virginia pine (tree mortality = 65-100% in Virginia pine versus 0-66% in loblolly pine), but in the latter, loblolly stands were more susceptible than Virginia stands. This hierarchical transition in host susceptibility was predicted from knowledge of (1) a behavioral preference of beetles for attacking loblolly versus Virginia pine, (2) a negative correlation between preference and performance, and (3) a mismatch in the domain of scale between demographics and host selection by individuals. There is value for forest management in understanding the processes that can produce hierarchical transitions in ecological patterns. Copyright ?? 2005 by the Society of American Foresters.

How parasitoid females produce sexy sons: a causal link between oviposition preference, dietary lipids and mate choice in Nasonia

PubMed Central

Blaul, Birgit; Ruther, Joachim

2011-01-01

Sexual selection theory predicts that phenotypic traits used to choose a mate should reflect honestly the quality of the sender and thus, are often costly. Physiological costs arise if a signal depends on limited nutritional resources. Hence, the nutritional condition of an organism should determine both its quality as a potential mate and its ability to advertise this quality to the choosing sex. In insects, the quality of the offspring's nutrition is often determined by the ovipositing female. A causal connection, however, between the oviposition decisions of the mother and the mating chances of her offspring has never been shown. Here, we demonstrate that females of the parasitic wasp Nasonia vitripennis prefer those hosts for oviposition that have been experimentally enriched in linoleic acid (LA). We show by 13C-labelling that LA from the host diet is a precursor of the male sex pheromone. Consequently, males from LA-rich hosts produce and release higher amounts of the pheromone and attract more virgin females than males from LA-poor hosts. Finally, males from LA-rich hosts possess three times as many spermatozoa as those from LA-poor hosts. Hence, females making the right oviposition decisions may increase both the fertility and the sexual attractiveness of their sons. PMID:21429922

How parasitoid females produce sexy sons: a causal link between oviposition preference, dietary lipids and mate choice in Nasonia.

PubMed

Blaul, Birgit; Ruther, Joachim

2011-11-07

Sexual selection theory predicts that phenotypic traits used to choose a mate should reflect honestly the quality of the sender and thus, are often costly. Physiological costs arise if a signal depends on limited nutritional resources. Hence, the nutritional condition of an organism should determine both its quality as a potential mate and its ability to advertise this quality to the choosing sex. In insects, the quality of the offspring's nutrition is often determined by the ovipositing female. A causal connection, however, between the oviposition decisions of the mother and the mating chances of her offspring has never been shown. Here, we demonstrate that females of the parasitic wasp Nasonia vitripennis prefer those hosts for oviposition that have been experimentally enriched in linoleic acid (LA). We show by (13)C-labelling that LA from the host diet is a precursor of the male sex pheromone. Consequently, males from LA-rich hosts produce and release higher amounts of the pheromone and attract more virgin females than males from LA-poor hosts. Finally, males from LA-rich hosts possess three times as many spermatozoa as those from LA-poor hosts. Hence, females making the right oviposition decisions may increase both the fertility and the sexual attractiveness of their sons.

Development of molecular methods to detect Macrophomina phaseolina from strawberry plants and soil

USDA-ARS?s Scientific Manuscript database

Macrophomina phaseolina is a broad-host range fungus that shows some degree of host preference on strawberry, and causes symptoms including charcoal rot and root rot. Recently, this pathogen has impacted strawberry production as fumigation practices have changed, leaving many growers in California a...

Manure preferences and postemergence learning of two filth fly parasitoids, Spalangia cameroni and Muscidifurax raptor (Hymenoptera: Pteromalidae)

USDA-ARS?s Scientific Manuscript database

The efficiency of host-seeking behavior is a crucial determinant of the reproductive performance of female parasitoids. Initially, parasitoids may use chemical information generated from the microhabitat in which they emerge to locate hosts. Spalangia cameroni and Muscidifurax raptor are commerciall...

Host boring preferences of the tea shot-hole borer Euwallacea fornicatus (Coleoptera: Curculionidae: Scolytinae)

USDA-ARS?s Scientific Manuscript database

The non-native shot-hole borer, Euwallacea nr. fornicatus Eichhoff (Coleoptera: Curculionidae: Scolytinae), was discovered in Florida’s avocado production area in Homestead in 2010. It is a highly polyphagous ambrosia beetle that carries Fusarium fungal symbionts. In susceptible host trees, the fung...

Role of plant volatiles in host plant recognition by Listronotus maculicollis (Coleoptera: Curculionidae)

USDA-ARS?s Scientific Manuscript database

The annual bluegrass weevil (ABW), Listronotus maculicollis Kirby, is an economically important pest of short cut turfgrass. ABW females prefer annual bluegrass, Poa annua L., for oviposition, and this grass species is a more suitable host for larvae compared to bentgrasses (Agrostis spp.). We inves...

Transgenic cry1C(⁎) gene rough rice line T1C-19 does not change the host preferences of the non-target stored product pest, Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae), and its parasitoid wasp, Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae).

PubMed

Sun, Xiao; Yan, Miao-Jun; Zhang, Aijun; Wang, Man-Qun

2015-10-01

Rough rice grains are often stored for extended periods before they are used or consumed. However, during storage, the rough rice is vulnerable to insect infestation, resulting in significant economic loss. Previous studies have shown that volatiles cues, physical characteristics, and taste chemicals on the grains could be the important key behavior factors for storage insect pests to locate the hosts and select oviposition sites. It is also well known that the transgenic Bt rough rice line T1C-19, which expresses a cry1C(⁎) gene has a high resistance to Lepidoptera pests. However, there were no evidences to show the consequences of host preference for non-target insect pests after growing Bt transgenic rice. In this study, the potential key factors of Bt rough rice were investigated for their impacts on the behaviors of non-target pest lesser grain borer Rhyzopertha dominica, the main weevil pest of grain and its parasitic wasps Anisopteromalus calandrae, the natural enemy of the beetle. Both electronic nose and electronic tongue analyses showed that the parameters of Bt rough rice were analogous to those of the non-Bt rough rice. The volatile profiles of Bt and non-Bt rough rice examined by gas chromatographic mass spectrometry (GC-MS) were similar. For most volatile compounds, there were no significantly quantitative differences in compound quantities between Bt and non-Bt rough rice. The densities of sclereids and trichomes on the rough rice husk surface were statistically equal in Bt and non-Bt rough rice. The non-target pest, R. dominica, and its parasitoid wasp, A. calandrae, were attracted to both rough rice and could not distinguish the transgenic T1C-19 from the isogenic rough rice. These results demonstrated that Bt rough rice has no negative impacts on the host preference behaviors of non-target stored product pest R. dominica and its parasitoid A. calandrae. Copyright © 2015 Elsevier Inc. All rights reserved.

The Benefit of Additional Oviposition Targets for a Polyphagous Butterfly

PubMed Central

Johansson, Josefin; Bergström, Anders; Janz, Niklas

2007-01-01

While the reasons for the prevalence of specialists over generalists among herbivorous insects have been at the focus of much interest, less effort has been put into understanding the polyphagous exceptions. Recent studies have suggested that these exceptions may be important for insect diversification, which calls for a better understanding of the potential factors that can lead to an increased host plant repertoire. Females of the Nymphalid butterfly, Polygonia c-album, were used to test if egg output and/or likelihood of finding a host increased with the addition of a secondary host. There was no effect of prior eggs on the host for willingness to oviposit on a plant. The main experiments were conducted both in small laboratory cages and in large outdoor experimental arenas. No positive effect was found when another oviposition target was added in small cages in the laboratory. On the other hand, in the outdoor arenas the females more often found a host to oviposit on and had a higher egg output when they had access to an additional host, even though the second host was lower in their preference hierarchy. The difference between these experiments was attributed to searching for acceptable host plants within a patch, a factor that was included in the large cages but not in the small. When host availability is limited, adding oviposition targets can potentially act to counterbalance specialization and thus favor the evolution of generalization. PMID:20334600

Profiling Diuraphis noxia (Hemiptera: Aphididae) Transcript Expression of the Biotypes SA1 and SAM Feeding on Various Triticum aestivum Varieties.

PubMed

Burger, N F V; Venter, E; Botha, A-M

2017-04-01

The intimate relationship between an aphid and its host is mediated by the composition of the secreted saliva. In the present study, aphid heads were sampled and transcript profiling conducted after aphids were fed on their preference host and transferred to a variety of preference and nonpreference hosts. It was found that the virulent Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) biotype SAM was able to selectively up-regulate more transcripts when confronted with feeding on a variety of hosts, than was the case with the less virulent D. noxia biotype SA1, suggesting increased genomic regulation when coping with a stressful environment. Collectively, the observed transcriptomic changes are supported by previous findings that host changes induce significant changes in the proteome of phytophagous hemipterans, unlike in many other entomophagous generalist species. The current data suggest that highly specialized hemipterans may be able to counter plant defenses with inducible salivary transcripts with resulting protein biosynthesis, as demonstrated here. © 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.

Cumulative effects of volcanic ash on the food preferences of two Orthopteran species.

PubMed

Fernández-Arhex, Valeria; Amadio, Maria E; Bruzzone, Octavio A

2017-08-01

Inert dusts are an early form of insecticide which is still in use. One of the most common inert dusts is volcanic ash. In order to study the reaction of rangeland grasshoppers, Dichroplus vittigerum (Acrididae) and a katydid, Burgilis mendosensis (Phaneropteridae), to the presence of volcanic ash in their food sources and how this reaction changed as a function of time, we conducted paired preference tests between clean leaves of their preferred host plant and leaves exposed to volcanic ash of different grain size. The behavioral response was measured as the rating on the Thurstonian preference scale of leaves with ash in relation to clean leaves. The results showed that the avoidance of volcanic ash increased as a function of time in both species. Both species studied are occasionally exposed to volcanic activity, and come from an area in which a volcanic eruption had recently occurred. As their populations did not decrease after the ash fall, we propose that some behavioral responses such as avoidance of places with ash, works as tolerance mechanism to inert dusts exposure. © 2016 Institute of Zoology, Chinese Academy of Sciences.

Herbivore Damage and Prior Egg Deposition on Host Plants Influence the Oviposition of the Generalist Moth Trichoplusia ni (Lepidoptera: Noctuidae).

PubMed

Coapio, Guadalupe G; Cruz-López, Leopoldo; Guerenstein, Pablo; Malo, Edi A; Rojas, Julio C

2016-12-01

Female insects have the difficult task of locating host plants that maximize the survival and success of their offspring. In this study, the oviposition preferences of the cabbage looper moth, Trichoplusia ni (Hübner), for soybean plants, Glycine max (L.), under various treatments-undamaged, mechanically damaged, damaged by T. ni or Spodoptera frugiperda (Smith) larvae or by Bemisia tabaci (Gennadius) adults, egg-free plants, and plants previously oviposited by conspecific or heterospecific females (S. frugiperda)-were investigated using two-choice tests. Additionally, the volatile compounds emitted by the plants under the different treatments were identified by gas chromatography-mass spectrometry. Our results showed that females showed no preferences for undamaged or mechanically damaged plants. However, they oviposited more often on undamaged plants than on those previously damaged by T. ni, S. frugiperda, or B. tabaci. In contrast, females preferred to oviposit on plants previously oviposited by conspecific and heterospecific females than on egg-free plants. Plants damaged by conspecific or heterospecific larvae emitted methyl salicylate, indole, and octyl butyrate, compounds not released by undamaged or mechanically damaged plants. Whitefly damage induced the release of higher quantities of Z(3)-hexenyl acetate, (R)-(+)-limonene, and (E)-β-ocimene compared to plants damaged by larvae and suppressed the emission of linalool. Egg deposition by conspecific and heterospecific moths induced the emission of (R)-(+)-limonene, octyl butyrate, and geranyl acetone but suppressed the release of linalool. This study showed that a generalist moth species can discriminate between plants of different quality, and suggests that females use volatile compounds as cues during this process. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Distribution and abundance of schistosomiasis and fascioliasis host snails along the Mara River in Kenya and Tanzania

PubMed Central

Dida, Gabriel O.; Gelder, Frank B.; Anyona, Douglas N.; Matano, Ally-Said; Abuom, Paul O.; Adoka, Samson O.; Ouma, Collins; Kanangire, Canisius K.; Owuor, Phillip O.; Ofulla, Ayub V. O.

2014-01-01

We purposively selected 39 sampling sites along the Mara River and its two perennial tributaries of Amala and Nyangores and sampled snails. In addition, water physicochemical parameters (temperature, turbidity, dissolved oxygen, conductivity, alkalinity, salinity and pH) were taken to establish their influence on the snail abundance and habitat preference. Out of the 39 sites sampled, 10 (25.6%) had snails. The snail species encountered included Biomphalaria pfeifferi Krauss – the intermediate host of Schistosoma mansoni Sambon, Bulinus africanus – the intermediate host of Schistosoma haematobium, and Lymnaea natalensis Krauss – the intermediate host of both Fasciola gigantica and F. hepatica Cobbold. Ceratophallus spp., a non-vector snail was also encountered. Most (61.0%) of the snails were encountered in streamside pools. Schistosomiasis-transmitting host snails, B. pfeifferi and B. africanus, were fewer than fascioliasis-transmitting Lymnaea species. All the four different snail species were found to be attached to different aquatic weeds, with B. pfeifferi accounting for over half (61.1%) of the snails attached to the sedge, followed by B. africanus and Lymnaea spp., accounting for 22.2 and 16.7%, respectively. Ceratophallus spp. were non-existent in sedge. The results from this preliminary study show that snails intermediate hosts of schistosomiasis and fascioliasis exists in different habitats, in few areas along the Mara River, though their densities are still low to have any noticeable impacts on disease transmission in case they are infected. The mere presence of the vector snails in these focal regions calls for their immediate control and institution of proper regulations, management, and education among the locals that can help curtail the spread of the snails and also schistosomiasis and fascioliasis within the Mara River basin. PMID:25405008

Amphibian chytridiomycosis: a review with focus on fungus-host interactions.

PubMed

Van Rooij, Pascale; Martel, An; Haesebrouck, Freddy; Pasmans, Frank

2015-11-25

Amphibian declines and extinctions are emblematic for the current sixth mass extinction event. Infectious drivers of these declines include the recently emerged fungal pathogens Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans (Chytridiomycota). The skin disease caused by these fungi is named chytridiomycosis and affects the vital function of amphibian skin. Not all amphibians respond equally to infection and host responses might range from resistant, over tolerant to susceptible. The clinical outcome of infection is highly dependent on the amphibian host, the fungal virulence and environmental determinants. B. dendrobatidis infects the skin of a large range of anurans, urodeles and caecilians, whereas to date the host range of B. salamandrivorans seems limited to urodeles. So far, the epidemic of B. dendrobatidis is mainly limited to Australian, neotropical, South European and West American amphibians, while for B. salamandrivorans it is limited to European salamanders. Other striking differences between both fungi include gross pathology and thermal preferences. With this review we aim to provide the reader with a state-of-the art of host-pathogen interactions for both fungi, in which new data pertaining to the interaction of B. dendrobatidis and B. salamandrivorans with the host's skin are integrated. Furthermore, we pinpoint areas in which more detailed studies are necessary or which have not received the attention they merit.

Unravelling the role of host plant expansion in the diversification of a Neotropical butterfly genus.

PubMed

McClure, Melanie; Elias, Marianne

2016-06-16

Understanding the processes underlying diversification is a central question in evolutionary biology. For butterflies, access to new host plants provides opportunities for adaptive speciation. On the one hand, locally abundant host species can generate ecologically significant selection pressure. But a diversity of host plant species within the geographic range of each population and/or species might also eliminate any advantage conferred by specialization. This paper focuses on four Melinaea species, which are oligophagous on the family Solanaceae: M. menophilus, M. satevis, M. marsaeus, and finally, M. mothone. We examined both female preference and larval performance on two host plant species that commonly occur in this butterfly's native range, Juanulloa parasitica and Trianaea speciosa, to determine whether the different Melinaea species show evidence of local adaptation. In choice experiments, M. mothone females used both host plants for oviposition, whereas all other species used J. parasitica almost exclusively. In no choice experiment, M. mothone was the only species that readily accepted T. speciosa as a larval host plant. Larval survival was highest on J. parasitica (82.0 % vs. 60.9 %) and development took longer on T. speciosa (14.12 days vs. 13.35 days), except for M. mothone, which did equally well on both host plants. For all species, average pupal weight was highest on J. parasitica (450.66 mg vs. 420.01 mg), although this difference was least apparent in M. mothone. We did not find that coexisting species of Melinaea partition host plant resources as expected if speciation is primarily driven by host plant divergence. Although M. mothone shows evidence of local adaptation to a novel host plant, T. speciosa, which co-occurs, it does not preferentially lay more eggs on or perform better on this host plant than on host plants used by other Melinaea species and not present in its distributional range. It is likely that diversification in this genus is driven by co-occurring Müllerian mimics and the resulting predation pressure, although this is also likely made possible by greater niche diversity as a consequence of plasticity for potential hosts.

Identification of Blood Meals from Potential Arbovirus Mosquito Vectors in the Peruvian Amazon Basin

PubMed Central

Palermo, Pedro M.; Aguilar, Patricia V.; Sanchez, Juan F.; Zorrilla, Víctor; Flores-Mendoza, Carmen; Huayanay, Anibal; Guevara, Carolina; Lescano, Andrés G.; Halsey, Eric S.

2016-01-01

The transmission dynamics of many arboviruses in the Amazon Basin region have not been fully elucidated, including the vectors and natural reservoir hosts. Identification of blood meal sources in field-caught mosquitoes could yield information for identifying potential arbovirus vertebrate hosts. We identified blood meal sources in 131 mosquitoes collected from areas endemic for arboviruses in the Peruvian Department of Loreto by sequencing polymerase chain reaction amplicons of the cytochrome b gene. Psorophora (Janthinosoma) albigenu, Psorophora (Grabhamia) cingulata, Mansonia humeralis, Anopheles oswaldoi s.l., and Anopheles benarrochi s.l. had mainly anthropophilic feeding preferences; Aedes (Ochlerotatus) serratus, and Aedes (Ochlerotatus) fulvus had feeding preferences for peridomestic animals; and Culex (Melanoconion) spp. fed on a variety of vertebrates, mainly rodents (spiny rats), birds, and amphibians. On the basis of these feeding preferences, many mosquitoes could be considered as potential enzootic and bridge arbovirus vectors in the Amazon Basin of Peru. PMID:27621304

Protected Repository for the Defense of Infrastructure Against Cyber Threats (PREDICT) Dataset Development and Hosting

DTIC Science & Technology

2018-04-01

Creation, curation and hosting of datasets for cybersecurity researchers; • Serving as a “host of convenience” for datasets from PREDICT and IMPACT non...assumptions and preferences, as cybersecurity investigators and proxies for the broader current and potential user communities. No attempt was made to...understand what would have been of use, i.e., cybersecurity researcher needs were known more anecdotally than systematically.[1] We believe that

Parasite transfer from crustacean to fish hosts in the Lübeck Bight, SW Baltic Sea

NASA Astrophysics Data System (ADS)

Zander, C. D.; Groenewold, S.; Strohbach, U.

1994-03-01

Four helminth parasites out of 19 species found in the Lübeck Bight, Baltic Sea, were chosen for investigations on the transfer from invertebrate to small-sized fish hosts: larvae of the tapeworms Schistocephalus sp. and Bothriocephalus sp. (Cestoda) living in planktonic copepods as primary hosts; Podocotyle atomon (Digenea) and Hysterothylacium sp. (Nematoda) were found in benthic crustaceans, especially Gammarus spp. These hosts were the prey of 3 gobiid fishes, Gobiusculus flavescens (feeding mainly on plankton), Pomatoschistus minutus (preferring benthos), and P. pictus (feeding more on plankton than benthos). Because the fishes selected smaller sizes of crustaceans, they ingested all stages of the copepods but only the smaller-sized groups of gammarids which were often less infested by parasites. In order to evaluate the probability for a fish to be parasitized by a helminth, an infestation potential index (IP) was calculated. Podocotyle atomon and Hysterothylacium sp. revealed an IP which was far lower in gobies than expected when the prevalences of the previous hosts were taken into consideration. The IP of tapeworm larvae was mainly influenced by the feeding pressure of the gobiid predators, which might change with developmental stage and season. It is concluded that parasite transfer to the next host decreases when sizes of prey and predator differ only moderately. This mechanism can reduce the numbers of parasites transferred to less suitable or wrong hosts.

Substrate preferences of epiphytic bromeliads: an experimental approach

NASA Astrophysics Data System (ADS)

Zotz, Gerhard; Vollrath, Birgit

2002-05-01

Based on the known vertical distributions of three epiphyte species we tested the hypothesis that observed interspecific differences are determined at a very early ontogenetic stage. We attached 1296 first-year seedlings of the three species Guzmania monostachya, Tillandsia fasciculata, and Vriesea sanguinolenta (Bromeliaceae) to substrates differing in orientation and relative position within the crown of the host tree, Annona glabra. Surprisingly, we found no evidence for differential mortality on different substrate types for any of the three species. Hence, differences in vertical distribution cannot be explained by interspecific differences in site-specific survival at this stage. This suggests that spatial distribution patterns are determined even earlier, probably resulting from species differences in seed dispersal or during germination.

Nutritional and defensive chemistry of three North American ash species: possible roles in host performance and preference by emerald ash borer

Treesearch

Yigen Chen; Therese M. Poland

2010-01-01

Black ash (Fraxinus nigra), green ash (F. pennsylvanica), and white ash (F. americana) are the three most abundant ash species in the northeastern USA. We compared emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), adult performance and preference among seedlings...

Teachers as Agents of Reception: An Analysis of Teacher Preference for Immigrant-Origin Second Language Learners

ERIC Educational Resources Information Center

Dabach, Dafney Blanca

2011-01-01

Scholarship on immigrant integration often examines immigrant characteristics and the host society's contexts of reception. This article explores how teachers fit within this framework by presenting findings on teachers' preferences to teach immigrant-origin youth who are classified as "English learners" (ELs) within separate content courses known…

Sequential divergence and the multiplicative origin of community diversity

PubMed Central

Hood, Glen R.; Forbes, Andrew A.; Powell, Thomas H. Q.; Egan, Scott P.; Hamerlinck, Gabriela; Smith, James J.; Feder, Jeffrey L.

2015-01-01

Phenotypic and genetic variation in one species can influence the composition of interacting organisms within communities and across ecosystems. As a result, the divergence of one species may not be an isolated process, as the origin of one taxon could create new niche opportunities for other species to exploit, leading to the genesis of many new taxa in a process termed “sequential divergence.” Here, we test for such a multiplicative effect of sequential divergence in a community of host-specific parasitoid wasps, Diachasma alloeum, Utetes canaliculatus, and Diachasmimorpha mellea (Hymenoptera: Braconidae), that attack Rhagoletis pomonella fruit flies (Diptera: Tephritidae). Flies in the R. pomonella species complex radiated by sympatrically shifting and ecologically adapting to new host plants, the most recent example being the apple-infesting host race of R. pomonella formed via a host plant shift from hawthorn-infesting flies within the last 160 y. Using population genetics, field-based behavioral observations, host fruit odor discrimination assays, and analyses of life history timing, we show that the same host-related ecological selection pressures that differentially adapt and reproductively isolate Rhagoletis to their respective host plants (host-associated differences in the timing of adult eclosion, host fruit odor preference and avoidance behaviors, and mating site fidelity) cascade through the ecosystem and induce host-associated genetic divergence for each of the three members of the parasitoid community. Thus, divergent selection at lower trophic levels can potentially multiplicatively and rapidly amplify biodiversity at higher levels on an ecological time scale, which may sequentially contribute to the rich diversity of life. PMID:26499247

Habitat and host indicate lineage identity in Colletotrichum gloeosporioides s.l. from wild and agricultural landscapes in North America

USDA-ARS?s Scientific Manuscript database

Understanding the factors that drive the evolution of pathogenic fungi is central to revealing the mechanisms of virulence and host preference, as well as developing effective disease control measures. Prerequisite to these pursuits is the accurate delimitation of species boundaries. Colletotrichu...

Role of volatile semiochemicals in the host and mate location behavior of Mallodon dasystomus (Coleoptera: Cerambycidae)

Treesearch

Matthew A. Paschen; Nathan M. Schiff; Matthew D. Ginzel

2012-01-01

Little is known of the role semiochemicals play in the mating systems of longhorned beetles (Coleoptera: Cerambycidae) in the primitive subfamily Prioninae. Mallodon dasystomus (Say), the hardwood stump borer, is a widely distributed prionine native to the southern US. Preferred hosts of M. dasystomus include oak, sweetgum,...

Stink bug host preferences: colonization, oviposition, and feeding on cotton.

USDA-ARS?s Scientific Manuscript database

Relative colonization rates of stink bug species among host crops grown in the Southeastern US are needed to parameterize a landscape model that seeks to predict stink bug populations in Bt cotton. We sampled stink bugs in Bt cotton, non-Bt cotton, soybean and peanuts over 3 years and 3 sites in the...

Competition between feeding guilds on cotton plants is species specific and likely plant-mediated.

USDA-ARS?s Scientific Manuscript database

Interspecific competition among herbivorous insects is often mediated by a common host plant. Changes in the common host plant induced by one herbivore species may make the plant less preferred or nutritious to another herbivore. We suggest that these interactions can be quite specific. We examine...

Relative longevity of adult Nezara viridula in field cages of cotton, peanut, and soybean

USDA-ARS?s Scientific Manuscript database

Recent evidence shows that southern green stink bugs use peanut as a reproductive host and adults colonize and feed in peanut, sometimes extensively. Stink bugs prefer the seeds/fruit of host plants and the fruiting structures in peanut are underground and unavailable. Therefore, it is not clear th...

Repellent properties of the host compound 4-allylanisole to the southern pine beetle

Treesearch

Jane Leslie Hayes; Brian L. Strom; Larry M. Roton; Leonard L. Ingram

1994-01-01

The phenylpropanoid 4-allylanisole is a compound produced by loblolly pines (Pinus taeda L.), an abundant species in southern pine forests and a preferred host of southern pine beetle (Dendroctonus frontalis Zimmermann).Repellency of individual beetles was demonstrated in laboratory behavioral assays of D. frontalis and other scolytids.Inhibition was...

Complexation of imidazopyridine-based cations with a 24-crown-8 ether host: [2]pseudorotaxane and partially threaded structures.

PubMed

Moreno-Olivares, Surisadai I; Cervantes, Ruy; Tiburcio, Jorge

2013-11-01

A new series of linear molecules derived from 1,2-bis(imidazopyridin-2-yl)ethane can fully or partially penetrate the cavity of the dibenzo-24-crown-8 macrocycle to produce a new family of host-guest complexes. Protonation or alkylation of the nitrogen atoms on the pyridine rings led to an increase in the guest total positive charge up to 4+ and simultaneously generated two new recognition sites (pyridinium motifs) that are in competition with the 1,2-bis(benzimidazole)ethane motif for the crown ether. The relative position of the pyridine ring and the chemical nature of the N-substituent determined the preferred motif and the host-guest complex geometry: (i) for linear guests with relatively bulky groups (i.e., a benzyl substituent), the 1,2-bis(benzimidazole)ethane motif is favored, leading to a fully threaded complex with a [2]pseudorotaxane geometry; (ii) for small substituents, such as -H and -CH3 groups, regardless of the guest shape, the pyridinium motifs are preferred, leading to external partially threaded complexes in a 2:1 host to guest stoichiometry.

Evolution on the move: specialization on widespread resources associated with rapid range expansion in response to climate change.

PubMed

Bridle, Jon R; Buckley, James; Bodsworth, Edward J; Thomas, Chris D

2014-02-07

Generalist species and phenotypes are expected to perform best under rapid environmental change. In contrast to this view that generalists will inherit the Earth, we find that increased use of a single host plant is associated with the recent climate-driven range expansion of the UK brown argus butterfly. Field assays of female host plant preference across the UK reveal a diversity of adaptations to host plants in long-established parts of the range, whereas butterflies in recently colonized areas are more specialized, consistently preferring to lay eggs on one host plant species that is geographically widespread throughout the region of expansion, despite being locally rare. By common-garden rearing of females' offspring, we also show an increase in dispersal propensity associated with the colonization of new sites. Range expansion is therefore associated with an increase in the spatial scale of adaptation as dispersive specialists selectively spread into new regions. Major restructuring of patterns of local adaptation is likely to occur across many taxa with climate change, as lineages suited to regional colonization rather than local success emerge and expand.

Duration of plant damage by host larvae affects attraction of two parasitoid species (Microplitis croceipes and Cotesia marginiventris) to cotton: implications for interspecific competition.

PubMed

Morawo, Tolulope; Fadamiro, Henry

2014-12-01

Volatile organic compounds (VOCs) released by herbivore-damaged plants can guide parasitoids to their hosts. The quantity and quality of VOC blends emitted by plants may be affected by the duration of plant damage by herbivores, which could have potential ramifications on the recruitment of competing parasitoids. We used two parasitoid species, Microplitis croceipes and Cotesia marginiventris (Hymenoptera: Braconidae), to address the question of whether duration of plant damage affects parasitoid use of plant VOCs for host location. Both wasp species are larval endoparasitoids of Heliothis virescens (Lepidoptera: Noctuidae), an important pest of cotton. Attraction of the two parasitoid species to odors emitted by undamaged (UD), fresh (6 h infestation) damage (FD), and old (24 h infestation) damage (OD) cotton plants infested by H. virescens larvae was investigated using a headspace volatile collection system coupled with four-choice olfactometer bioassay. Both sexes of M. croceipes showed a preference for FD- and OD-plant odors over UD-plants. On the other hand, more C. marginiventris females were attracted to UD- and FD-plants than to OD-plants. GC/MS analyses showed qualitative and quantitative differences in the VOC profiles of UD, FD, and OD-plants, which may explain the observed preferences of the parasitoids. These results suggest a temporal partitioning in the recruitment of M. croceipes and C. marginiventris to H. virescens-damaged cotton, and may have potential implications for interspecific competition between the two parasitoid species.

Site Occupation of Eu2+ in Ba2- xSr xSiO4 ( x = 0-1.9) and Origin of Improved Luminescence Thermal Stability in the Intermediate Composition.

PubMed

Lin, Litian; Ning, Lixin; Zhou, Rongfu; Jiang, Chunyan; Peng, Mingying; Huang, Yucheng; Chen, Jun; Huang, Yan; Tao, Ye; Liang, Hongbin

2018-06-18

Knowledge of site occupation of activators in phosphors is of essential importance for understanding and tailoring their luminescence properties by modifying the host composition. Relative site preference of Eu 2+ for the two distinct types of alkaline earth (AE) sites in Ba 1.9995- x Sr x Eu 0.0005 SiO 4 ( x = 0-1.9) is investigated based on photoluminescence measurements at low temperature. We found that Eu 2+ prefers to be at the 9-coordinated AE2 site at x = 0, 0.5, and 1.0, while at x = 1.5 and 1.9, it also occupies the 10-coordinated AE1 site with comparable preference, which is verified by density functional theory (DFT) calculations. Moreover, by combining low-temperature measurements of the heat capacity, the host band gap, and the Eu 2+ 4f 7 ground level position, the improved thermal stability of Eu 2+ luminescence in the intermediate composition ( x = 1.0) is interpreted as due to an enlarged energy gap between the emitting 5d level and the bottom of the host conduction band (CB), which results in a decreased nonradiative probability of thermal ionization of the 5d electron into the host CB. Radioluminescence properties of the samples under X-ray excitation are finally evaluated, suggesting a great potential scintillator application of the compound in the intermediate composition.

Where are the horses? With the sheep or cows? Uncertain host location, vector-feeding preferences and the risk of African horse sickness transmission in Great Britain

PubMed Central

Lo Iacono, Giovanni; Robin, Charlotte A.; Newton, J. Richard; Gubbins, Simon; Wood, James L. N.

2013-01-01

Understanding the influence of non-susceptible hosts on vector-borne disease transmission is an important epidemiological problem. However, investigation of its impact can be complicated by uncertainty in the location of the hosts. Estimating the risk of transmission of African horse sickness (AHS) in Great Britain (GB), a virus transmitted by Culicoides biting midges, provides an insightful example because: (i) the patterns of risk are expected to be influenced by the presence of non-susceptible vertebrate hosts (cattle and sheep) and (ii) incomplete information on the spatial distribution of horses is available because the GB National Equine Database records owner, rather than horse, locations. Here, we combine land-use data with available horse owner distributions and, using a Bayesian approach, infer a realistic distribution for the location of horses. We estimate the risk of an outbreak of AHS in GB, using the basic reproduction number (R0), and demonstrate that mapping owner addresses as a proxy for horse location significantly underestimates the risk. We clarify the role of non-susceptible vertebrate hosts by showing that the risk of disease in the presence of many hosts (susceptible and non-susceptible) can be ultimately reduced to two fundamental factors: first, the abundance of vectors and how this depends on host density, and, second, the differential feeding preference of vectors among animal species. PMID:23594817

A Game of Russian Roulette for a Generalist Dinoflagellate Parasitoid: Host Susceptibility Is the Key to Success

PubMed Central

Alacid, Elisabet; Park, Myung G.; Turon, Marta; Petrou, Katherina; Garcés, Esther

2016-01-01

Marine microbial interactions involving eukaryotes and their parasites play an important role in shaping the structure of phytoplankton communities. These interactions may alter population densities of the main host, which in turn may have consequences for the other concurrent species. The effect generalist parasitoids exert on a community is strongly dependent on the degree of host specificity. Parvilucifera sinerae is a generalist parasitoid able to infect a wide range of dinoflagellates, including toxic-bloom-forming species. A density-dependent chemical cue has been identified as the trigger for the activation of the infective stage. Together these traits make Parvilucifera-dinoflagellate hosts a good model to investigate the degree of specificity of a generalist parasitoid, and the potential effects that it could have at the community level. Here, we present for the first time, the strategy by which a generalist dinoflagellate parasitoid seeks out its host and determine whether it exhibits host preferences, highlighting key factors in determining infection. Our results demonstrate that in its infective stage, P. sinerae is able to sense potential hosts, but does not actively select among them. Instead, the parasitoids contact the host at random, governed by the encounter probability rate and once encountered, the chance to penetrate inside the host cell and develop the infection strongly depends on the degree of host susceptibility. As such, their strategy for persistence is more of a game of Russian roulette, where the chance of survival is dependent on the susceptibility of the host. Our study identifies P. sinerae as a potential key player in community ecology, where in mixed dinoflagellate communities consisting of hosts that are highly susceptible to infection, parasitoid preferences may mediate coexistence between host species, reducing the dominance of the superior competitor. Alternatively, it may increase competition, leading to species exclusion. If, however, highly susceptible hosts are absent from the community, the parasitoid population could suffer a dilution effect maintaining a lower parasitoid density. Therefore, both host community structure and host susceptibility will determine infectivity in the field. PMID:27252688

Oviposition Preference and Survival of the Mexican Rice Borer (Lepidoptera: Crambidae) in Bioenergy and Conventional Sugarcane and Sorghum.

PubMed

VanWeelden, M T; Wilson, B E; Beuzelin, J M; Reagan, T E; Way, M O

2017-08-01

Oviposition preference and host suitability of the Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), on bioenergy and conventional cultivars of sugarcane, Saccharum spp., and sorghum, Sorghum spp., were examined in a series of greenhouse experiments. Two energycane cultivars, two sugarcane cultivars, two high-biomass sorghum cultivars, and one sweet sorghum cultivar were assessed at two phenological stages (immature and mature). Mature plants possessed greater availability of dry leaf material compared with immature plants, and all E. loftini eggs were observed exclusively on dry leaves. Oviposition did not vary among host combinations (cultivar by phenological stage); however, eggs per plant and eggs per oviposition event were numerically greater on mature plants than immature plants. In a no-choice experiment, survival from egg to adult did not vary among host combinations, with <2.0% of E. loftini larvae surviving to adulthood. Failed establishment by neonates on plants was 13.4- to 53.9-fold greater than successful establishment across all host combinations. Results from this study suggest that plant physical characteristics continue to play an important role in host selection, but further evaluations will be needed to quantify other characteristics which influence host suitability. © 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.

Host-seeking strategies of mosquito disease vectors.

PubMed

Day, Jonathan F

2005-12-01

Disease transmission by arthropods normally requires at least 2 host contacts. During the first, a pathogen (nematode, protozoan, or virus) is acquired along with the blood from an infected vertebrate host. The pathogen penetrates the vector's midgut and infects a variety of tissues, where replication may occur during an extrinsic incubation period lasting 3-30, days depending on vector and parasite physiology and ambient temperature. Following salivary-gland infection, the pathogen is usually transmitted to additional susceptible vertebrate hosts during future probing or blood feeding. The host-seeking strategies used by arthropod vectors can, in part, affect the efficiency of disease transmission. Vector abundance, seasonal distribution, habitat and host preference, and susceptibility to infection are all important components of disease-transmission cycles. Examples of 3 mosquito vectors of human disease are presented here to highlight the diversity of host seeking and to show how specific behaviors may influence disease-transmission cycles. In the African tropics, Anopheles gambiae s.s. is an efficient vector of human malaria due to its remarkably focused preference for human blood. Aedes aegypti is the main vector of dengue viruses in the New and Old World tropics and subtropics. This mosquito has evolved a domestic lifestyle and shares human habitations throughout much of its range. It prospers in settings where humans are its main source of blood. In south Florida, Culex nigripalpus is the major vector of St. Louis encephalitis (SLE) and West Nile (WN) viruses. This mosquito is opportunistic and blood feeds on virtually any available vertebrate host. It serves as an arboviral vector, in part, due to its ability to produce large populations in a short period of time. These 3 host-seeking and blood-feeding strategies make the specialist, as well as the opportunist, equally dangerous disease vectors.

Behavioral asymmetries in ticks - Lateralized questing of Ixodes ricinus to a mechatronic apparatus delivering host-borne cues.

PubMed

Benelli, Giovanni; Romano, Donato; Rocchigiani, Guido; Caselli, Alice; Mancianti, Francesca; Canale, Angelo; Stefanini, Cesare

2018-02-01

Ticks are considered among the most dangerous arthropod vectors of disease agents to both humans and animals worldwide. Lateralization contributes to biological fitness in many animals, conferring important functional advantages, therefore studying its role in tick perception would critically improve our knowledge about their host-seeking behavior. In this research, we evaluated if Ixodes ricinus (L.) (Ixodiidae) ticks have a preference in using the right or the left foreleg to climb on a host. We developed a mechatronic device moving a tuft of fox skin with fur as host-mimicking combination of cues. This engineered approach allows to display a realistic combination of both visual and olfactory host-borne stimuli, which is prolonged over the time and standardized for each replicate. In the first experiment, the mechatronic apparatus delivered host-borne cues frontally, to evaluate the leg preference during questing as response to a symmetrical stimulus. In the second experiment, host-borne cues were provided laterally, in an equal proportion to the left and to the right of the tick, to investigate if the host direction affected the questing behavior. In both experiments, the large majority of the tested ticks showed individual-level left-biased questing acts, if compared to the ticks showing right-biased ones. Furthermore, population-level left-biased questing responses were observed post-exposure to host-mimicking cues provided frontally or laterally to the tick. Overall, this is the first report on behavioral asymmetries in ticks of medical and veterinary importance. Moreover, the mechatronic apparatus developed in this research can be exploited to evaluate the impact of repellents on tick questing in highly reproducible standardized conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Habitat Preferences of Boros schneideri (Coleoptera: Boridae) in the Natural Tree Stands of the Białowieża Forest

PubMed Central

Gutowski, Jerzy M.; Sućko, Krzysztof; Zub, Karol; Bohdan, Adam

2014-01-01

Abstract We analyzed habitat requirements of Boros schneideri (Panzer, 1796) (Coleoptera: Boridae) in the natural forests of the continental biogeographical region, using data collected in the Białowieża Forest. This species has been found on the six host trees, but it preferred dead, standing pine trees, characterized by large diameter, moderately moist and moist phloem but avoided trees in sunny locations. It occurred mostly in mesic and wet coniferous forests. This species demonstrated preferences for old tree stands (over 140-yr old), and its occurrence in younger tree-stand age classes (minimum 31–40-yr old) was not significantly different from random distribution. B. schneideri occupied more frequently locations distant from the forest edge, which were less affected by logging. Considering habitat requirements, character of occurrence, and decreasing number of occupied locations in the whole range of distribution, this species can be treated as relict of primeval forests. PMID:25527586

Genetic variation of Anastrepha suspensa (Diptera: Tephritidae) in Florida and the Caribbean using microsatellite DNA markers.

PubMed

Boykin, Laura M; Shatters, Robert G; Hall, David G; Dean, David; Beerli, Peter

2010-12-01

Anastrepha suspensa (Loew) (Diptera: Tephritidae), the Caribbean fruit fly, is indigenous to Florida and the Greater Antilles where it causes economic losses in fruit crops, including citrus. Because of the geographic separation of many of its native locations and anecdotal descriptions of regional differences in host preferences, there have been questions about the population structure of A. suspensa. Seven DNA microsatellite markers were used to characterize the population genetic structure of A. suspensa, in Florida and the Caribbean from a variety of hosts, including citrus. We genotyped 729 A. suspensa individuals from Florida, Puerto Rico, Cayman Island, Dominican Republic, and Jamaica. The investigated seven loci displayed from 5 to 19 alleles, with expected heterozygosities ranging from 0.05 to 0.83. There were five unique alleles in Florida and three unique alleles in the Caribbean samples; however, no microsatellite alleles were specific to a single host plant. Genetic diversity was analyzed using F(ST) and analysis of molecular variance and revealed low genetic diversity between Florida and Caribbean samples and also between citrus and noncitrus samples. Analyses using migrate revealed there is continuous gene flow between sampling sites in Florida and the Caribbean and among different hosts. These results support previous comparisons based on the mitochondrial cytochrome oxidase I locus indicating there is no genetic differentiation among locations in Florida and the Caribbean and that there is no separation into host races.

Genetic structure and natural variation associated with host of origin in Penicillium expansum strains causing blue mould.

PubMed

Sanzani, S M; Montemurro, C; Di Rienzo, V; Solfrizzo, M; Ippolito, A

2013-07-15

Blue mould, caused by Penicillium expansum, is one of the most economically damaging postharvest diseases of pome fruits, although it may affect a wider host range, including sweet cherries and table grapes. Several reports on the role of mycotoxins in plant pathogenesis have been published, but few focussed on the influence of mycotoxins on the variation in host preference amongst producing fungi. In the present study the influence of the host on P. expansum pathogenicity/virulence was investigated, focussing mainly on the relationship with patulin production. Three P. expansum strain groups, originating from apples, sweet cherries, and table grapes (7 strains per host) were grown on their hosts of isolation and on artificial media derived from them. Strains within each P. expansum group proved to be more aggressive and produced more patulin than the other two groups under evaluation when grown on the host from which they originated. Table grape strains were the most aggressive (81% disease incidence) and strongest patulin producers (up to 554μg/g). The difference in aggressiveness amongst strains was appreciable only in the presence of a living host, suggesting that the complex pathogen-host interaction significantly influenced the ability of P. expansum to cause the disease. Incidence/severity of the disease and patulin production proved to be positively correlated, supporting the role of patulin as virulence/pathogenicity factor. The existence of genetic variation amongst isolates was confirmed by the High Resolution Melting method that was set up herein, which permitted discrimination of P. expansum from other species (P. chrysogenum and P. crustosum) and, within the same species, amongst the host of origin. Host effect on toxin production appeared to be exerted at a transcriptional level. Copyright © 2013 Elsevier B.V. All rights reserved.

Colonization preference of Eushcistus servus and Nezara viridula in transgenic cotton varieties, peanut and soybean

USDA-ARS?s Scientific Manuscript database

Because cotton, peanuts and soybean crops are often grown in close proximity and are hosts for the major pest stink bug species: -- the southern green stink bug, the brown stink bug, and the green stink bug – in the region, we determined colonization preference of these species among the crops to cl...

Host-seeking height preferences of Aedes albopictus (Diptera: Culicidae) in North-central Florida suburban and sylvatic locales

USDA-ARS?s Scientific Manuscript database

The response of Aedes albopictus to the BG-Sentinel™, Omni-directional-Fay-Prince and Mosquito Magnet-X traps was evaluated in four suburban and four sylvatic habitats in North-Central Florida to ascertain potential height preference of this species. These traps, which are primarily designed to att...

Vitellogenin and vitellogenin receptor gene expression profiles in Spodoptera exigua are related to host plant suitability.

PubMed

Zhao, Jing; Sun, Yang; Xiao, Liubin; Tan, Yongan; Jiang, Yiping; Bai, Lixin

2018-04-01

The beet armyworm Spodoptera exigua, a worldwide phytophagous pest, causes considerable economic agricultural losses. Understanding the relationship between its fecundity and the host plant is a basic and important component of early forecasting of beet armyworm outbreaks. However, little is known about the molecular mechanism by which distinct hosts affect S. exigua fecundity. In this study, key life-history parameters of S. exigua reared on distinct hosts were investigated; the host plants could be ranked as lettuce > shallot > tomato > celery in their order of suitability. Full-length S. exigua vitellogenin receptor (SeVgR) cDNA was cloned, and sex-, stage- and tissue-specific expression characteristics were assessed. Spodoptera exigua vitellogenin (SeVg) and SeVgR expression levels were markedly modulated by host nutrients (P < 0.05). SeVg and SeVgR expression levels were significantly higher in S. exigua reared on lettuce, the most preferred and most nutritive host, than in those reared on tomato and celery. Interestingly, significant linear regression correlations were found between SeVg and SeVgR expression levels and key S. exigua life-history parameters, especially life span, pupa weight, and female fecundity (P < 0.01). Host plant type and suitability could affect the expression pattern of SeVg and SeVgR, which influenced S. exigua fecundity. Vg and VgR have the potential to be used as molecular markers of S. exigua fecundity and for forecasting outbreaks of S. exigua on different hosts. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Aphid-induced Defences in Chilli Affect Preferences of the Whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae).

PubMed

Saad, Khalid A; Mohamad Roff, M N; Hallett, Rebecca H; Idris, A B

2015-09-03

The sweetpotato whitefly (WF), Bemisia tabaci, is a major pest that damages a wide range of vegetable crops in Malaysia. WF infestation is influenced by a variety of factors, including previous infestation of the host plant by other insect pests. This study investigated the effects of previous infestation of host chilli plants by the green peach aphid (Myzus persicae) on the olfactory behavioural response of B. tabaci, using free-choice bioassay with a Y-tube olfactometer. We analysed volatile organic compounds (VOCs) emitted by non-infested and M. persicae-infested chilli plants using solid-phase microextraction and gas chromatography-mass spectrometry. Our results showed that female WFs preferred non-infested to pre-infested plants. Collection and analysis of volatile compounds emitted by infested plants confirmed that there were significant increases in the production of monoterpenes (cymene; 1,8-cineole), sesquiterpenes (β-cadinene, α-copaene), and methyl salicylate (MeSA) compared to non-infested plants. Our results suggest that host plant infestation by aphids may induce production of secondary metabolites that deter B. tabaci from settling on its host plants. These results provide important information for understanding WF host selection and dispersal among crops, and also for manipulating WF behaviour to improve IPM in chilli.

Host breadth and ovipositional behavior of adult Polydrusus sericeus and Phyllobius oblongus (Coleoptera: Curculionidae), nonindigenous inhabitants of northern hardwood forests

Treesearch

R. A. Pinski; W. J. Mattson; K. F. Raffa

2005-01-01

Polydrusus sericeus (Schaller) and Phyllobius oblongus (L.) are nonindigenous root-feeding weevils in northern hardwood forests of Wisconsin and Michigan. Detailed studies of adult host range, tree species preferences, and effects of food source on fecundity and longevity have not been conducted in North America P....

Relationship between foliar chemistry and insect performance: the forest tent caterpillar

Treesearch

Francois Lorenzetti; Yves Mauffette; Eric Bauce

1999-01-01

Forest tent caterpillar (FTC) feeds on several species of deciduous trees (Stehr and Cook 1968), in northeastern North America, quaking aspen is the preferred host of this spring-feeding insect. FTC commonly defoliates several thousands of hectares of aspen stands each year in Quebec (Bordeleau 1990), although its secondary hosts seldom are attacked.

The influence of aphids (Myzus persicae) and pink lady beetle larvae (Coleomegilla maculata) on host plant preference of imported cabbageworm (Pieris rapae)

USDA-ARS?s Scientific Manuscript database

Oviposition decisions by herbivorous insects hinge on multiple factors; host plant quality, enemy free space, plant density, offspring performance, and competition for resources all which influence decisions by an ovipositing female. Here, we evaluate whether the presence of aphids (a competitor) or...

Spatial distribution, seasonality and trap preference of stable fly, Stomoxys calcitrans L. (Diptera: Muscidae), adults on a 12-hectare zoological park

USDA-ARS?s Scientific Manuscript database

Stomoxys calcitrans (L.) is a biting fly of extreme economic importance and can cause adverse economic effects on host animals. Within zoological parks, hosts may include practically any accessible animal (e.g., sheep, goats, cows, camels, equines, primates, canids, and felids). In many animals, e....

Relative Suitability of Virginia Pine and Loblolly Pine as Host Species for Dendroctonus frontalis (Coleoptera: Scolytidae)

Treesearch

Jessica S. Veysey; Matthew P. Ayres; Maria J. Lombardero; Richard W. Hofstetter; Kier D. Klepzig

2003-01-01

Dendroctonus frontalis is a major disturbance agent in American pine forests, but attack preferences for various host species, and their relative suitability for reproduction, are poorly knowi). We studied patterns of beetle attack and reproduction during an infestation of stands contairiing Virginia pine and lol~lolly pine. Nearly all Virginia pine...

Molecular diversity of arbuscular mycorrhizal fungi and their distribution patterns related to host-plants and habitats in a hot and arid ecosystem, southwest China.

PubMed

Li, Ling-Fei; Li, Tao; Zhang, Yan; Zhao, Zhi-Wei

2010-03-01

The communities of arbuscular mycorrhizal fungi (AMF) colonizing the roots of Bothriochloa pertusa, Cajanus cajan and Heteropogon contortus in a fallow land (FL) and an undisturbed land (UL) were characterized. The large subunit rDNA genes of AMF from roots were amplified and cloned. A total of 2353 clones were screened by restriction fragment length polymorphism, and 428 clones were subsequently sequenced. A total of 393 AMF sequences, which were grouped into 100 operational taxonomic units, were obtained. Phylogenetic analysis revealed that the AMF sequences belonged to Glomus, Acaulospora and Scutellospora, and that Glomus was the dominant genus. Of the 393 AMF sequences, 81% were novel. The diversity of AMF colonizing the same plant species was higher in the UL than in the FL, which confirmed strongly from the molecular evidence that soil disturbance reduced AMF population and species richness. The results revealed that AMF communities were significantly different among host-plant species and between the two habitats. The similarity of AMF communities colonizing different plant species within a habitat was higher than that of the same plant species from different habitats. The molecular evidence supported our previous hypothesis based on morphological analyses that AMF communities were more influenced by habitats compared with host preference.

Metazoan ectoparasites of Atlantic mackerel, Scomber scombrus (Teleostei: Scombridae): macro- and microhabitat distribution.

PubMed

Castro, Ricardo; Santos, Maria João

2013-10-01

Parasites are affected by the environment where their hosts live, having a specific distribution among their hosts and occupying a well-defined microhabitat. The present work aims to describe the metazoan ectoparasite fauna of Scomber scombrus, namely its distribution at the macro- and microhabitat levels. For that, fish from two different Portuguese regions, Matosinhos (n = 40) and Figueira da Foz (n = 39), were examined for macroectoparasites. S. scombrus of Matosinhos presented four different parasite species, whilst fish from Figueira da Foz presented five species. All parasites belonged to Monogenea, Copepoda, or Isopoda. The main differences between infection levels of fish from the two localities were found in Grubea cochlear (higher infection levels in Matosinhos) and Caligus pelamydis (where the highest values were found in Figueira da Foz). Regarding the microhabitat of the reported ectoparasites, it could be seen that every species has a very specific distribution within the host: G. cochlear and Kuhnia scombri have a preference for the inner medial areas of gills, Kuhnia sprostonae for the pseudobranchs, and C. pelamydis for the internal wall of opercula. The numerical and functional responses to interspecific competition were absent. These results support the idea that the parasite driving forces of community structure are the reinforcement of reproductive barriers and the enhancement of chances to mate.

Identification of leaf volatiles from olive (Olea europaea) and their possible role in the ovipositional preferences of olive fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae).

PubMed

Malheiro, Ricardo; Casal, Susana; Cunha, Sara C; Baptista, Paula; Pereira, José Alberto

2016-01-01

The olive fly, Bactrocera oleae (Rossi), is a monophagous pest that displays an oviposition preference among cultivars of olive (Olea europaea L.). To clarify the oviposition preference, the olive leaf volatiles of three olive cultivars (Cobrançosa, Madural and Verdeal Transmontana) were assessed by headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) at six different periods of olive fruit maturation and degrees of infestation. A total of 39 volatiles were identified, mainly esters and alcohols, with a minor percentage of aldehydes, ketones and terpenic compounds, including sesquiterpenes. At sampling dates with higher degrees of infestation, cv. Cobrançosa had, simultaneously, significantly lower infestation degrees and higher volatile amounts than the other two cultivars, with a probable deterrent effect for oviposition. The green leaf volatiles (GLVs) (Z)-3-hexen-1-ol and (Z)-3-hexen-1-ol acetate) were the main compounds identified in all cultivars, together with toluene. The abundance of GLVs decreased significantly throughout maturation, without significant differences among cultivars, while toluene showed a general increase and positive correlation with olive fly infestation levels. The results obtained could broaden our understanding of the roles of various types and amounts of olive volatiles in the environment, especially in olive fly host selection and cultivar preference. Copyright © 2015 Elsevier Ltd. All rights reserved.

Selection of Apis mellifera workers by the parasitic mite Varroa destructor using host cuticular hydrocarbons.

PubMed

Del Piccolo, F; Nazzi, F; Della Vedova, G; Milani, N

2010-05-01

The parasitic mite, Varroa destructor, is the most important threat for apiculture in most bee-keeping areas of the world. The mite is carried to the bee brood cell, where it reproduces, by a nurse bee; therefore the selection of the bee stage by the parasite could influence its reproductive success. This study investigates the role of the cuticular hydrocarbons of the European honeybee (Apis mellifera) in host-selection by the mite. Preliminary laboratory bioassays confirmed the preference of the varroa mite for nurse bees over pollen foragers. GC-MS analysis of nurse and pollen bees revealed differences in the cuticular hydrocarbons of the two stages; in particular, it appeared that pollen bees have more (Z)-8-heptadecene than nurse bees. Laboratory experiments showed that treatment of nurse bees with 100 ng of the pure compound makes them repellent to the varroa mite. These results suggest that the mite can exploit the differences in the cuticular composition of its host for a refined selection that allows it to reach a brood cell and start reproduction. The biological activity of the alkene encourages further investigations for the development of novel control techniques based on this compound.

An investigation of virulence factors of Legionella pneumophila environmental isolates.

PubMed

Arslan-Aydoğdu, Elif Özlem; Kimiran, Ayten

Nine Legionella pneumophila strains isolated from cooling towers and a standard strain (L. pneumophila serogroup 1, ATCC 33152, Philadelphia 1) were analyzed and compared in terms of motility, flagella structure, ability to form biofilms, enzymatic activities (hemolysin, nucleases, protease, phospholipase A, phospholipase C, acid phosphatase, alkaline phosphatase and lipase), hemagglutination capabilities, and pathogenicity in various host cells (Acanthamoeba castellanii ATCC 30234, mouse peritoneal macrophages and human peripheral monocytes). All the isolates of bacteria appeared to be motile and polar-flagellated and possessed the type-IV fimbria. Upon the evaluation of virulence factors, isolate 4 was found to be the most pathogenic strain, while 6 out of the 9 isolates (the isolates 1, 2, 3, 4, 5, and 7) were more virulent than the ATCC 33152 strain. The different bacterial strains exhibited differences in properties such as adhesion, penetration and reproduction in the hosts, and preferred host type. To our knowledge, this is the first study to compare the virulence of environmental L. pneumophila strains isolated in Turkey, and it provides important information relevant for understanding the epidemiology of L. pneumophila. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Preference for C4 shade grasses increases hatchling performance in the butterfly, Bicyclus safitza.

PubMed

Nokelainen, Ossi; Ripley, Brad S; van Bergen, Erik; Osborne, Colin P; Brakefield, Paul M

2016-08-01

The Miocene radiation of C4 grasses under high-temperature and low ambient CO 2 levels occurred alongside the transformation of a largely forested landscape into savanna. This inevitably changed the host plant regime of herbivores, and the simultaneous diversification of many consumer lineages, including Bicyclus butterflies in Africa, suggests that the radiations of grasses and grazers may be evolutionary linked. We examined mechanisms for this plant-herbivore interaction with the grass-feeding Bicyclus safitza in South Africa. In a controlled environment, we tested oviposition preference and hatchling performance on local grasses with C3 or C4 photosynthetic pathways that grow either in open or shaded habitats. We predicted preference for C3 plants due to a hypothesized lower processing cost and higher palatability to herbivores. In contrast, we found that females preferred C4 shade grasses rather than either C4 grasses from open habitats or C3 grasses. The oviposition preference broadly followed hatchling performance, although hatchling survival was equally good on C4 or C3 shade grasses. This finding was explained by leaf toughness; shade grasses were softer than grasses from open habitats. Field monitoring revealed a preference of adults for shaded habitats, and stable isotope analysis of field-sampled individuals confirmed their preference for C4 grasses as host plants. Our findings suggest that plant-herbivore interactions can influence the direction of selection in a grass-feeding butterfly. Based on this work, we postulate future research to test whether these interactions more generally contribute to radiations in herbivorous insects via expansions into new, unexploited ecological niches.

Recombinant glucose uptake system

DOEpatents

Ingrahm, Lonnie O.; Snoep, Jacob L.; Arfman, Nico

1997-01-01

Recombinant organisms are disclosed that contain a pathway for glucose uptake other than the pathway normally utilized by the host cell. In particular, the host cell is one in which glucose transport into the cell normally is coupled to PEP production. This host cell is transformed so that it uses an alternative pathway for glucose transport that is not coupled to PEP production. In a preferred embodiment, the host cell is a bacterium other than Z. mobilis that has been transformed to contain the glf and glk genes of Z. mobilis. By uncoupling glucose transport into the cell from PEP utilization, more PEP is produced for synthesis of products of commercial importance from a given quantity of biomass supplied to the host cells.

Characteristics of the association between the marine copepod, Gastrodelphys clausii, and its fanworm host Bispira volutacornis

NASA Astrophysics Data System (ADS)

Nash, Róisín; Keegan, Brendan F.

2006-03-01

Characteristics of the association of the marine copepod Gastrodelphys clausii with its fanworm host Bispira volutacornis were investigated from October 1997 to August 1999. Of the 982 hosts examined, 22.6% were infected, with male copepods outnumbering females. Prevalence varied between 3 and 90% during the study period and showed a seasonal pattern with a summer and late autumn/winter peak. Hosts were observed to harbour both single and multiple infections. The aggregation of parasites within the host population was overdispersed, displaying a characteristically clumped pattern. G. clausii reaches adulthood in males at ca. 800 μm in length, with recorded total lengths extending to 1,875 μm. Females at maturity were recorded to be ca. 1,000 μm, with a maximum total length of 3,250 μm recorded for an ovigerous female. Copepods were mobile within the branchial crown and showed no statistical preference for branchial crowns of different sizes. A positional pattern, however, was observed with juvenile copepods observed to occupy radioles further from the prostomium, as the branchial crown increases the number of radioles in each spiral. Contrary to this, the majority of female copepods were located attached to the radioles closest to the prostomium irrespective of crown size.

Investigating interactions between phospholipase B-Like 2 and antibodies during Protein A chromatography.

PubMed

Tran, Benjamin; Grosskopf, Vanessa; Wang, Xiangdan; Yang, Jihong; Walker, Don; Yu, Christopher; McDonald, Paul

2016-03-18

Purification processes for therapeutic antibodies typically exploit multiple and orthogonal chromatography steps in order to remove impurities, such as host-cell proteins. While the majority of host-cell proteins are cleared through purification processes, individual host-cell proteins such as Phospholipase B-like 2 (PLBL2) are more challenging to remove and can persist into the final purification pool even after multiple chromatography steps. With packed-bed chromatography runs using host-cell protein ELISAs and mass spectrometry analysis, we demonstrated that different therapeutic antibodies interact to varying degrees with host-cell proteins in general, and PLBL2 specifically. We then used a high-throughput Protein A chromatography method to further examine the interaction between our antibodies and PLBL2. Our results showed that the co-elution of PLBL2 during Protein A chromatography is highly dependent on the individual antibody and PLBL2 concentration in the chromatographic load. Process parameters such as antibody resin load density and pre-elution wash conditions also influence the levels of PLBL2 in the Protein A eluate. Furthermore, using surface plasmon resonance, we demonstrated that there is a preference for PLBL2 to interact with IgG4 subclass antibodies compared to IgG1 antibodies. Copyright © 2016 Elsevier B.V. All rights reserved.

Metatranscriptomic Study of Common and Host-Specific Patterns of Gene Expression between Pines and Their Symbiotic Ectomycorrhizal Fungi in the Genus Suillus

PubMed Central

Liao, Hui-Ling; Chen, Yuan; Vilgalys, Rytas

2016-01-01

Ectomycorrhizal fungi (EMF) represent one of the major guilds of symbiotic fungi associated with roots of forest trees, where they function to improve plant nutrition and fitness in exchange for plant carbon. Many groups of EMF exhibit preference or specificity for different plant host genera; a good example is the genus Suillus, which grows in association with the conifer family Pinaceae. We investigated genetics of EMF host-specificity by cross-inoculating basidiospores of five species of Suillus onto ten species of Pinus, and screened them for their ability to form ectomycorrhizae. Several Suillus spp. including S. granulatus, S. spraguei, and S. americanus readily formed ectomycorrhizae (compatible reaction) with white pine hosts (subgenus Strobus), but were incompatible with other pine hosts (subgenus Pinus). Metatranscriptomic analysis of inoculated roots reveals that plant and fungus each express unique gene sets during incompatible vs. compatible pairings. The Suillus-Pinus metatranscriptomes utilize highly conserved gene regulatory pathways, including fungal G-protein signaling, secretory pathways, leucine-rich repeat and pathogen resistance proteins that are similar to those associated with host-pathogen interactions in other plant-fungal systems. Metatranscriptomic study of the combined Suillus-Pinus transcriptome has provided new insight into mechanisms of adaptation and coevolution of forest trees with their microbial community, and revealed that genetic regulation of ectomycorrhizal symbiosis utilizes universal gene regulatory pathways used by other types of fungal-plant interactions including pathogenic fungal-host interactions. PMID:27736883

Relationship between soil nutrients and mycorrhizal associations of two Bipinnula species (Orchidaceae) from central Chile.

PubMed

Mujica, María Isabel; Saez, Nicolás; Cisternas, Mauricio; Manzano, Marlene; Armesto, Juan J; Pérez, Fernanda

2016-07-01

Mycorrhizal associations are influenced by abiotic and biotic factors, including climate, soil conditions and the identity of host plants. However, the effect of environmental conditions on orchid mycorrhizal associations remains poorly understood. The present study examined how differences in soil nutrient availability are related to the diversity and composition of mycorrhizal fungi associated with two terrestrial orchid species from central Chile. For 12 populations of Bipinnula fimbriata and B. plumosa, OTU (operational taxonomic unit) richness, phylogenetic diversity and community composition of mycorrhizal fungi in root samples were estimated using internal transcribed spacer (ITS) sequences. Then, these mycorrhizal diversity variables were related to soil nutrients and host species using generalized linear models and non-metric multidimensional scaling. Variation in OTU composition of mycorrhizal fungi among sites was explained mainly by orchid host species. Fungi in Tulasnellaceae and Ceratobasidiaceae were isolated from both orchid species, but the former were more frequent in B. fimbriata and the latter in B. plumosa. Soil nutrients and orchid host species had significant effects on OTU richness and phylogenetic diversity. Mycorrhizal diversity decreased in habitats with higher N in both species and increased with P availability only in B. fimbriata The results suggest that soil nutrient availability modulates orchid mycorrhizal associations and provide support for the hypothesis that specialization is favoured by higher soil nutrient availability. Inter-specific differences in mycorrhizal composition can arise due to a geographical pattern of distribution of orchid mycorrhizal fungi, host preferences for fungal partners or differential performance of mycorrhizal fungi under different nutrient availabilities. Further experiments are needed to evaluate these hypotheses. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Relationship between soil nutrients and mycorrhizal associations of two Bipinnula species (Orchidaceae) from central Chile

PubMed Central

Mujica, María Isabel; Saez, Nicolás; Cisternas, Mauricio; Manzano, Marlene; Armesto, Juan J.; Pérez, Fernanda

2016-01-01

Background and Aims Mycorrhizal associations are influenced by abiotic and biotic factors, including climate, soil conditions and the identity of host plants. However, the effect of environmental conditions on orchid mycorrhizal associations remains poorly understood. The present study examined how differences in soil nutrient availability are related to the diversity and composition of mycorrhizal fungi associated with two terrestrial orchid species from central Chile. Methods For 12 populations of Bipinnula fimbriata and B. plumosa, OTU (operational taxonomic unit) richness, phylogenetic diversity and community composition of mycorrhizal fungi in root samples were estimated using internal transcribed spacer (ITS) sequences. Then, these mycorrhizal diversity variables were related to soil nutrients and host species using generalized linear models and non-metric multidimensional scaling. Key Results Variation in OTU composition of mycorrhizal fungi among sites was explained mainly by orchid host species. Fungi in Tulasnellaceae and Ceratobasidiaceae were isolated from both orchid species, but the former were more frequent in B. fimbriata and the latter in B. plumosa. Soil nutrients and orchid host species had significant effects on OTU richness and phylogenetic diversity. Mycorrhizal diversity decreased in habitats with higher N in both species and increased with P availability only in B. fimbriata. Conclusions The results suggest that soil nutrient availability modulates orchid mycorrhizal associations and provide support for the hypothesis that specialization is favoured by higher soil nutrient availability. Inter-specific differences in mycorrhizal composition can arise due to a geographical pattern of distribution of orchid mycorrhizal fungi, host preferences for fungal partners or differential performance of mycorrhizal fungi under different nutrient availabilities. Further experiments are needed to evaluate these hypotheses. PMID:27311572

In-planta Sporulation Capacity Enhances Infectivity and Rhizospheric Competitiveness of Frankia Strains.

PubMed

Cotin-Galvan, Laetitia; Pozzi, Adrien C; Schwob, Guillaume; Fournier, Pascale; Fernandez, Maria P; Herrera-Belaroussi, Aude

2016-01-01

Frankia Sp+ strains maintain their ability to sporulate in symbiosis with actinorhizal plants, producing abundant sporangia inside host plant cells, in contrast to Sp- strains, which are unable to perform in-planta sporulation. We herein examined the role of in-planta sporulation in Frankia infectivity and competitiveness for root infection. Fifteen strains belonging to different Sp+ and Sp- phylogenetic lineages were inoculated on seedlings of Alnus glutinosa (Ag) and A. incana (Ai). Strain competitiveness was investigated by performing Sp-/Sp+ co-inoculations. Plant inoculations were standardized using crushed nodules obtained under laboratory-controlled conditions (same plant species, age, and environmental factors). Specific oligonucleotide primers were developed to identify Frankia Sp+ and/or Sp- strains in the resulting nodules. Single inoculation experiments showed that (i) infectivity by Sp+ strains was significantly greater than that by Sp- strains, (ii) genetically divergent Sp+ strains exhibited different infective abilities, and (iii) Sp+ and Sp- strains showed different host preferences according to the origin (host species) of the inocula. Co-inoculations of Sp+ and Sp- strains revealed the greater competitiveness of Sp+ strains (98.3 to 100% of Sp+ nodules, with up to 15.6% nodules containing both Sp+ and Sp- strains). The results of the present study highlight differences in Sp+/Sp- strain ecological behaviors and provide new insights to strengthen the obligate symbiont hypothesis for Sp+ strains.

In-planta Sporulation Capacity Enhances Infectivity and Rhizospheric Competitiveness of Frankia Strains

PubMed Central

Cotin-Galvan, Laetitia; Pozzi, Adrien C.; Schwob, Guillaume; Fournier, Pascale; Fernandez, Maria P.; Herrera-Belaroussi, Aude

2016-01-01

Frankia Sp+ strains maintain their ability to sporulate in symbiosis with actinorhizal plants, producing abundant sporangia inside host plant cells, in contrast to Sp− strains, which are unable to perform in-planta sporulation. We herein examined the role of in-planta sporulation in Frankia infectivity and competitiveness for root infection. Fifteen strains belonging to different Sp+ and Sp− phylogenetic lineages were inoculated on seedlings of Alnus glutinosa (Ag) and A. incana (Ai). Strain competitiveness was investigated by performing Sp−/Sp+ co-inoculations. Plant inoculations were standardized using crushed nodules obtained under laboratory-controlled conditions (same plant species, age, and environmental factors). Specific oligonucleotide primers were developed to identify Frankia Sp+ and/or Sp− strains in the resulting nodules. Single inoculation experiments showed that (i) infectivity by Sp+ strains was significantly greater than that by Sp− strains, (ii) genetically divergent Sp+ strains exhibited different infective abilities, and (iii) Sp+ and Sp− strains showed different host preferences according to the origin (host species) of the inocula. Co-inoculations of Sp+ and Sp− strains revealed the greater competitiveness of Sp+ strains (98.3 to 100% of Sp+ nodules, with up to 15.6% nodules containing both Sp+ and Sp− strains). The results of the present study highlight differences in Sp+/Sp− strain ecological behaviors and provide new insights to strengthen the obligate symbiont hypothesis for Sp+ strains. PMID:26726131

Tea green leafhopper, Empoasca vitis, chooses suitable host plants by detecting the emission level of (3Z)-hexenyl acetate.

PubMed

Xin, Z-J; Li, X-W; Bian, L; Sun, X-L

2017-02-01

Green leaf volatiles (GLVs) have been reported to play an important role in the host-locating behavior of several folivores that feed on angiosperms. However, next to nothing is known about how the green leafhopper, Empoasca vitis, chooses suitable host plants and whether it detects differing emission levels of GLV components among genetically different tea varieties. Here we found that the constitutive transcript level of the tea hydroperoxide lyase (HPL) gene CsiHPL1, and the amounts of (Z)-3-hexenyl acetate and of total GLV components are significantly higher in tea varieties that are susceptible to E. vitis (Enbiao (EB) and Banzhuyuan (BZY)) than in varieties that are resistant to E. vitis (Changxingzisun (CX) and Juyan (JY)). Moreover, the results of a Y-tube olfactometer bioassay and an oviposition preference assay suggest that (Z)-3-hexenyl acetate and (Z)-3-hexenol offer host and oviposition cues for E. vitis female adults. Taken together, the two GLV components, (Z)-3-hexenol and especially (Z)-3-hexenyl acetate, provide a plausible mechanism by which tea green leafhoppers distinguish among resistant and susceptible varieties. Future research should be carried out to obtain the threshold of the above indices and then assess their reasonableness. The development of practical detection indices would greatly improve our ability to screen and develop tea varieties that are resistant to E. vitis.

Effects of Coralliophila violacea on tissue loss in the scleractinian corals Porites spp. depend on host response

USGS Publications Warehouse

Raymundo, L.; Work, Thierry M.; Miller, R.L.; Lozada-Misa, P.L.

2016-01-01

We investigated interactions between the corallivorous gastropod Coralliophila violacea and its preferred hosts Porites spp. Our objectives were to experimentally determine whether tissue loss could progress in Porites during or after Coralliophila predation on corals with and without tissue loss and to histologically document snail predation. In 64% of feeding scars, tissue regenerated within 3 wk, leaving no trace of predation. However, in roughly 28% of scars, lesions progressed to subacute tissue loss resembling white syndrome. In feeding experiments, scars from snails previously fed diseased tissue developed progressive tissue loss twice as frequently as scars from snails previously fed healthy tissue. Scars from previously healthy-fed snails were 3 times as likely to heal as those from previously diseased-fed snails. Histology revealed marked differences in host responses to snails; P. cylindrica manifested a robust inflammatory response with fewer secondary colonizing organisms such as algae, sponges, and helminths, whereas P. rus showed no evident inflammation and more secondary colonization. We conclude that lesion progression associated with Coralliophila may be associated with secondary colonization of coral tissues damaged by predator-induced trauma and necrosis. Importantly, variation at the cellular level should be considered when explaining interspecific differences in host responses in corals impacted by phenomena such as predation.

Prevalence and site preferences of heterophyid metacercariae in Tilapia zilli from Ismalia fresh water canal, Egypt.

PubMed

Ibrahim, M M; Soliman, M F M

2010-09-01

Factors affecting prevalence and site preferences of heterophyid metacercariae (MC) were investigated in this study. A total of 173 specimens of a freshwater fish, Tilapia zilli were collected during autumn 2008, winter 2009 and summer 2009, from Ismailia fresh water canal, Egypt. Results showed that the total prevalence of heterophyid MC was 95.37%. The heterophyid MC consisted of Haplorchis yokogawi (47.4%), Pygidiopsis genata (21.4%), and Phagicola ascolonga (93.64%). H. yokogawi MC was detected in striated muscles, P. ascolonga in liver and kidney while, P. genata was detected in muscles, liver and kidney. The aggregation indices showed that all MC were aggregated and the P. genata was the most highly aggregated followed by H. yokogawi and then P. ascolonga. Responses of the heterophyid MC to host sex, weight and season greatly varied according to species of MC. Different responses of interaction for heterophyid MC intensity were found by GLIM analysis and this variation dependant on the type of infection (single or mixed infections). Factors affecting site preference of heterophid MC infection were discussed and further studies in other locations are required to examine the factors affecting site preference.

Innate host selection in Anopheles vestitipennis from southern Mexico.

PubMed

Ullo, Armando; Arredondo-Jiménez, Juan I; Rodríguez, Mario H; Fernández-Salas, Ildefonso; González-Cerón, Lilia

2004-12-01

We assessed the degree of host specificity of the purported anthropophilic and zoophilic populations of Anopheles vestitipennis. A series of experiments were conducted in an experimental hut with 3 compartments lined with nylon netting. A central release compartment and 2 side compartments were each baited with equivalent surface area of human and animal baits. Wild An. vestitipennis collected on each host, as well as corresponding F1 mosquitoes, were released in the central compartment. Overall, 22% (166/748) of all mosquitoes collected on humans were recaptured in the human compartment, whereas 23% of mosquitoes originally collected on animals were recaptured in this compartment. Experiments with F1 females resulted in 59% human selection rates, a 2.6 times increase compared with wild anthropophilic females, while a 1.2 times decrease in human selection rates (from 24% to 20%) was observed in F1 of wild zoophilic females. Host selection experiments in the Lacandón Forest revealed the same trend. These findings suggested that the complex mode of inheritance that resulted in female mosquitoes showing a stronger tendency to return to their preferred host was obscured by the nature of the method of collection, i.e., wild parental females selecting a host either innately or opportunistically, the majority of which were likely innately attracted. This was revealed by F1 females, of which, when given the choice to select a host, a higher proportion opted for the preferred one. The results presented here are in accordance with other studies that identified a subpopulation of An. vestitipennis in southern Mexico with higher anthropophily.

Short- and long-range cues used by ground-dwelling parasitoids to find their host

NASA Astrophysics Data System (ADS)

Goubert, C.; Josso, C.; Louâpre, P.; Cortesero, A. M.; Poinsot, D.

2013-02-01

Parasitoids of phytophagous insects face a detectability-reliability dilemma when foraging for hosts. Plant-related cues are easily detectable, but do not guarantee the presence of the host. Host-related cues are very reliable, but much harder to detect from a distance. Little is known in particular about the way coleopteran parasitoid females use these cues when foraging for a suitable place to lay their eggs. The question is of interest because, unlike hymenopteran larvae, coleopteran parasitoid larvae are highly mobile and able to forage for hosts on their own. We assessed whether females of the parasitoid rove beetle Aleochara bipustulata (L.) (Coleoptera: Staphylinidae) are attracted to plant (Swede roots, Brassica napus) and host-related cues [pupae of the cabbage root fly Delia radicum (L.) (Diptera: Anthomyiidae)]. In the field, A. bipustulata adult females were captured in selective pitfall traps containing pieces of roots damaged by D. radicum larvae, but not in traps containing pieces of healthy roots or D. radicum pupae. However, in the laboratory, the odour of D. radicum pupae attracted A. bipustulata females to mini-pitfalls. Video monitoring in the laboratory showed that foraging A. bipustulata females preferred a zone containing D. radicum pupae and larval tracks rather than one containing an extract of D. radicum-infested roots. Our results suggest a behavioural sequence where A. bipustulata females use plant-related cues at a distance, but then switch their preference to host-related cues at a close range. This would be the first observation of this behaviour in coleopteran parasitoids.

Retrospective and prospective perspectives on zoonotic brucellosis

PubMed Central

Moreno, Edgardo

2014-01-01

Members of the genus Brucella are pathogenic bacteria exceedingly well adapted to their hosts. The bacterium is transmitted by direct contact within the same host species or accidentally to secondary hosts, such as humans. Human brucellosis is strongly linked to the management of domesticated animals and ingestion of their products. Since the domestication of ungulates and dogs in the Fertile Crescent and Asia in 12000 and 33000 ya, respectively, a steady supply of well adapted emergent Brucella pathogens causing zoonotic disease has been provided. Likewise, anthropogenic modification of wild life may have also impacted host susceptibility and Brucella selection. Domestication and human influence on wild life animals are not neutral phenomena. Consequently, Brucella organisms have followed their hosts’ fate and have been selected under conditions that favor high transmission rate. The “arm race” between Brucella and their preferred hosts has been driven by genetic adaptation of the bacterium confronted with the evolving immune defenses of the host. Management conditions, such as clustering, selection, culling, and vaccination of Brucella preferred hosts have profound influences in the outcome of brucellosis and in the selection of Brucella organisms. Countries that have controlled brucellosis systematically used reliable smooth live vaccines, consistent immunization protocols, adequate diagnostic tests, broad vaccination coverage and sustained removal of the infected animals. To ignore and misuse tools and strategies already available for the control of brucellosis may promote the emergence of new Brucella variants. The unrestricted use of low-efficacy vaccines may promote a “false sense of security” and works towards selection of Brucella with higher virulence and transmission potential. PMID:24860561

The Host Galaxies of Fast-Ejecta Core-Collapse Supernovae

NASA Technical Reports Server (NTRS)

Kelly, Patrick L.; Filippenko, Alexei V.; Modjaz, Maryam; Kocevski, Daniel

2014-01-01

Spectra of broad-lined Type Ic supernovae (SN Ic-BL), the only kind of SN observed at the locations of long-duration gamma-ray bursts (LGRBs), exhibit wide features indicative of high ejecta velocities ((is) approximately 0.1c). We study the host galaxies of a sample of 245 low-redshift (z (is) less than 0.2) core-collapse SN, including 17 SN Ic-BL, discovered by galaxy-untargeted searches, and 15 optically luminous and dust-obscured z (is) less than 1.2 LGRBs. We show that, in comparison with SDSS galaxies having similar stellar masses, the hosts of low-redshift SN Ic- BL and z (is) is less than 1.2 LGRBs have high stellar-mass and star-formation-rate densities. Core-collapse SN having typical ejecta velocities, in contrast, show no preference for such galaxies. Moreover, we find that the hosts of SN Ic-BL, unlike those of SN Ib/Ic and SN II, exhibit high gas velocity dispersions for their stellar masses. The patterns likely reflect variations among star-forming environments, and suggest that LGRBs can be used as probes of conditions in high-redshift galaxies. They may be caused by efficient formation of massive binary progenitors systems in densely star-forming regions, or, less probably, a higher fraction of stars created with the initial masses required for a SN Ic-BL or LGRB. Finally, we show that the preference of SN Ic-BL and LGRBs for galaxies with high stellar-mass and star-formation-rate densities cannot be attributed to a preference for low metal abundances but must reflect the influence of a separate environmental factor.

Effects of visual silhouette, leaf size and host species on feeding preference by adult emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae)

Treesearch

Deepa S. Pureswaran; Therese M. Poland

2009-01-01

The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) is an invasive species recently established in North America. In large arena bioassays, when given a choice among live green ash, Fraxinus pennsylvanica Marsh and artificial ash saplings that were hidden or exposed from view, beetles preferred live...

Identification of Blood Meals from Potential Arbovirus Mosquito Vectors in the Peruvian Amazon Basin.

PubMed

Palermo, Pedro M; Aguilar, Patricia V; Sanchez, Juan F; Zorrilla, Víctor; Flores-Mendoza, Carmen; Huayanay, Anibal; Guevara, Carolina; Lescano, Andrés G; Halsey, Eric S

2016-11-02

The transmission dynamics of many arboviruses in the Amazon Basin region have not been fully elucidated, including the vectors and natural reservoir hosts. Identification of blood meal sources in field-caught mosquitoes could yield information for identifying potential arbovirus vertebrate hosts. We identified blood meal sources in 131 mosquitoes collected from areas endemic for arboviruses in the Peruvian Department of Loreto by sequencing polymerase chain reaction amplicons of the cytochrome b gene. Psorophora (Janthinosoma) albigenu, Psorophora (Grabhamia) cingulata, Mansonia humeralis, Anopheles oswaldoi s.l., and Anopheles benarrochi s.l. had mainly anthropophilic feeding preferences; Aedes (Ochlerotatus) serratus, and Aedes (Ochlerotatus) fulvus had feeding preferences for peridomestic animals; and Culex (Melanoconion) spp. fed on a variety of vertebrates, mainly rodents (spiny rats), birds, and amphibians. On the basis of these feeding preferences, many mosquitoes could be considered as potential enzootic and bridge arbovirus vectors in the Amazon Basin of Peru. © The American Society of Tropical Medicine and Hygiene.

Experimental malaria-associated acute respiratory distress syndrome is dependent on the parasite-host combination and coincides with normocyte invasion.

PubMed

Vandermosten, Leen; Pham, Thao-Thy; Possemiers, Hendrik; Knoops, Sofie; Van Herck, Evelien; Deckers, Julie; Franke-Fayard, Blandine; Lamb, Tracey J; Janse, Chris J; Opdenakker, Ghislain; Van den Steen, Philippe E

2018-03-05

Malaria-associated acute respiratory distress syndrome (MA-ARDS) is a complication of malaria with a lethality rate of up to 80% despite anti-malarial treatment. It is characterized by a vast infiltration of leukocytes, microhaemorrhages and vasogenic oedema in the lungs. Previously, a mouse model for MA-ARDS was developed by infection of C57BL/6 mice with the Edinburgh line NK65-E of Plasmodium berghei. Here, both host and parasite factors were demonstrated to play crucial roles in the development and severity of lung pathology. In particular, the genetic constitution of the host was an important determinant in the development of MA-ARDS. Both male and female C57BL/6, but not BALB/c, mice developed MA-ARDS when infected with P. berghei NK65-E. However, the New York line of P. berghei NK65 (NK65-NY) did not induce demonstrable MA-ARDS, despite its accumulation in the lungs and fat tissue to a similar or even higher extent as P. berghei NK65-E. These two commonly used lines of P. berghei differ in their red blood cell preference. P. berghei NK65-NY showed a stronger predilection for reticulocytes than P. berghei NK65-E and this appeared to be associated with a lower pathogenicity in the lungs. The pulmonary pathology in the C57BL/6/P. berghei NK65-E model was more pronounced than in the model with infection of DBA/2 mice with P. berghei strain ANKA. The transient lung pathology in DBA/2 mice infected with P. berghei ANKA coincided with the infection phase in which parasites mainly infected normocytes. This phase was followed by a less pathogenic phase in which P. berghei ANKA mainly infected reticulocytes. The propensity of mice to develop MA-ARDS during P. berghei infection depends on both host and parasite factors and appears to correlate with RBC preference. These data provide insights in induction of MA-ARDS and may guide the choice of different mouse-parasite combinations to study lung pathology.

Peripheral and Central Olfactory Tuning in a Moth

PubMed Central

Ong, Rose C.

2012-01-01

Animals can be innately attracted to certain odorants. Because these attractants are particularly salient, they might be expected to induce relatively strong responses throughout the olfactory pathway, helping animals detect the most relevant odors but limiting flexibility to respond to other odors. Alternatively, specific neural wiring might link innately preferred odors to appropriate behaviors without a need for intensity biases. How nonpheromonal attractants are processed by the general olfactory system remains largely unknown. In the moth Manduca sexta, we studied this with a set of innately preferred host plant odors and other, neutral odors. Electroantennogram recordings showed that, as a population, olfactory receptor neurons (ORNs) did not respond with greater intensity to host plant odors, and further local field potential recordings showed that no specific amplification of signals induced by host plant odors occurred between the first olfactory center and the second. Moreover, when odorants were mutually diluted to elicit equally intense output from the ORNs, moths were able to learn to associate all tested odorants equally well with food reward. Together, these results suggest that, although nonpheromonal host plant odors activate broadly distributed responses, they may be linked to attractive behaviors mainly through specific wiring in the brain. PMID:22362866

A comparison of fungal endophytic community diversity in tree leaves of rural and urban temperate forests of Kanto district, eastern Japan.

PubMed

Matsumura, Emi; Fukuda, Kenji

2013-03-01

To clarify the effects of forest fragmentation and a change in tree species composition following urbanization on endophytic fungal communities, we isolated fungal endophytes from the foliage of nine tree species in suburban (Kashiwa City, Chiba) and rural (Mt. Wagakuni, Ibaraki; Mt. Takao, Tokyo) forests and compared the fungal communities between sites and host tree species. Host specificity was evaluated using the index of host specificity (Si), and the number of isolated species, total isolation frequency, and the diversity index were calculated. From just one to several host-specific species were recognized in all host tree species at all sites. The total isolation frequency of all fungal species on Quercus myrsinaefolia, Quercus serrata, and Chamaecyparis obtusa and the total isolation frequency of host-specific species on Q. myrsinaefolia, Q. serrata, and Eurya japonica were significantly lower in Kashiwa than in the rural forests. The similarity indices (nonmetric multidimensional scaling (NMS) and CMH) of endophytic communities among different tree species were higher in Kashiwa, as many tree species shared the same fungal species in the suburban forest. Endophytic fungi with a broad host range were grouped into four clusters suggesting their preference for conifer/broadleaves and evergreen/deciduous trees. Forest fragmentation and isolation by urbanization have been shown to cause the decline of host-specific fungal species and a decrease in β diversity of endophytic communities, i.e., endophytic communities associated with tree leaves in suburban forests were found to be depauperate. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Host specificity of two pollinating seed-consuming fly species is not related to soil moisture of host plant in the high Himalayas.

PubMed

Song, Bo; Stöcklin, Jürg; Gao, Yong-Qian; Peng, De-Li; Sun, Hang

2017-01-01

Studying the drivers of host specificity can contribute to our understanding of the origin and evolution of obligate pollination mutualisms. The preference-performance hypothesis predicts that host plant choice of female insects is related mainly to the performance of their offspring. Soil moisture is thought to be particularly important for the survival of larvae and pupae that inhabit soil. In the high Himalayas, Rheum nobile and R. alexandrae differ in their distribution in terms of soil moisture; that is, R. nobile typically occurs in scree with well-drained soils, R. alexandrae in wetlands. The two plant species are pollinated by their respective mutualistic seed-consuming flies, Bradysia sp1. and Bradysia sp2. We investigated whether soil moisture is important for regulating host specificity by comparing pupation and adult emergence of the two fly species using field and laboratory experiments. Laboratory experiments revealed soil moisture did have significant effects on larval and pupal performances in both fly species, but the two fly species had similar optimal soil moisture requirements for pupation and adult emergence. Moreover, a field reciprocal transfer experiment showed that there was no significant difference in adult emergence for both fly species between their native and non-native habitats. Nevertheless, Bradysia sp1., associated with R. nobile , was more tolerant to drought stress, while Bradysia sp2., associated with R. alexandrae , was more tolerant to flooding stress. These results indicate that soil moisture is unlikely to play a determining role in regulating host specificity of the two fly species. However, their pupation and adult emergence in response to extremely wet or dry soils are habitat-specific.

Treatment of oral mucosal manifestations of chronic graft-versus-host disease: dexamethasone vs. budesonide.

PubMed

Zadik, Yehuda; Elad, Sharon; Shapira, Anat; Shapira, Michael Y

2017-02-01

The oral mucosa is commonly involved in chronic graft-versus-host disease (cGVHD). Oral mucosal cGVHD markedly affect individual's daily function and wellbeing. In some cases, it might become a life threating complication. Areas covered: This article describes the rationale for treatment, method of topical application in the oral cavity, evidence supporting the topical administration of dexamethasone and budesonide for oral cGVHD, and their adverse effects. Expert opinion: Evidence supports the use of topical dexamethasone and budesonide for treatment of oral cGVHD. Topical corticosteroid choice for oral cGVHD, takes into consideration the potency, bioavailability, preferred concentration, and possible adverse effects. Budesonide's pharmacological characteristics mark it as a preferable topical agent for oral cGVHD.

Host population density as the major determinant of endoparasite species richness in floodplain fishes of the upper Paraná River, Brazil.

PubMed

Takemoto, R M; Pavanelli, G C; Lizama, M A P; Luque, J L; Poulin, R

2005-03-01

A comparative analysis of parasite species richness was performed across 53 species of fish from the floodplain of the upper Paraná River, Brazil. Values of catch per unit effort, CPUE (number of individuals of a given fish species captured per 1000 m(2) of net during 24 h) were used as a rough measure of population density for each fish species in order to test its influence on endoparasite species richness. The effects of several other host traits (body size, social behaviour, reproductive behaviour, spawning type, trophic category, feeding habits, relative position in the food web, preference for certain habitats and whether the fish species are native or exotic) on metazoan endoparasite species richness were also evaluated. The CPUE was the sole significant predictor of parasite species richness, whether controlling for the confounding influences of host phylogeny and sampling effort or not. The results suggest that in the floodplain of the upper Paraná River (with homogeneous physical characteristics and occurrence of many flood pulses), population density of different host species might be the major determinant of their parasite species richness.

Evaluating the growth potential of sea lampreys (Petromyzon marinus) feeding on siscowet lake trout (Salvelinus namaycush) in Lake Superior

USGS Publications Warehouse

Moody, E.K.; Weidel, B.C.; Ahrenstorff, T.D.; Mattes, W.P.; Kitchell, J.F.

2011-01-01

Differences in the preferred thermal habitat of Lake Superior lake trout morphotypes create alternative growth scenarios for parasitic sea lamprey (Petromyzon marinus) attached to lake trout hosts. Siscowet lake trout (Salvelinus namaycush) inhabit deep, consistently cold water (4–6 °C) and are more abundant than lean lake trout (Salvelinus namaycush) which occupy temperatures between 8 and 12 °C during summer thermal stratification. Using bioenergetics models we contrasted the growth potential of sea lampreys attached to siscowet and lean lake trout to determine how host temperature influences the growth and ultimate size of adult sea lamprey. Sea lampreys simulated under the thermal regime of siscowets are capable of reaching sizes within the range of adult sea lamprey sizes observed in Lake Superior tributaries. High lamprey wounding rates on siscowets suggest siscowets are important lamprey hosts. In addition, siscowets have higher survival rates from lamprey attacks than those observed for lean lake trout which raises the prospect that siscowets serve as a buffer to predation on more commercially desirable hosts such as lean lake trout, and could serve to subsidize lamprey growth.

To feed or not to feed: plant factors located in the epidermis, mesophyll, and sieve elements influence pea aphid's ability to feed on legume species.

PubMed

Schwarzkopf, Alexander; Rosenberger, Daniel; Niebergall, Martin; Gershenzon, Jonathan; Kunert, Grit

2013-01-01

The pea aphid (Acyrthosiphon pisum Harris), a legume specialist, encompasses at least 11 genetically distinct sympatric host races. Each host race shows a preference for a certain legume species. Six pea aphid clones from three host races were used to localize plant factors influencing aphid probing and feeding behavior on four legume species. Aphid performance was tested by measuring survival and growth. The location of plant factors influencing aphid probing and feeding was determined using the electrical penetration graph (EPG) technique. Every aphid clone performed best on the plant species from which it was originally collected, as well as on Vicia faba. On other plant species, clones showed intermediate or poor performance. The most important plant factors influencing aphid probing and feeding behavior were localized in the epidermis and sieve elements. Repetitive puncturing of sieve elements might be relevant for establishing phloem feeding, since feeding periods appear nearly exclusively after these repetitive sieve element punctures. A combination of plant factors influences the behavior of pea aphid host races on different legume species and likely contributes to the maintenance of these races.

Loading and conjugating cavity biostructures

DOEpatents

Hainfeld, J.F.

1997-11-25

Methods for the preparation and use of a biological delivery system are disclosed. The method of preparation includes the loading of a non-biological material into a biostructure having a load-bearing structure. The method also includes the removal of some of the biostructure`s contents and the loading of a non-biological material into the biostructure. The biostructure is biologically compatible with the host, and preferably is derived from the host, the host`s species or a related species. The loaded biostructure is used directly, or it can be targeted to specific cells, tissues and/or organs within a host. The targeted biostructure can be used to deliver the non-biological material to a specified tissue, organ or cell within a host for diagnostic, therapeutic or other purposes. 11 figs.

Loading and conjugating cavity biostructures

DOEpatents

Hainfeld, J.F.

1995-08-22

Methods for the preparation and use of a biological delivery system are disclosed. The method of preparation includes the loading of a non-biological material into a biostructure having a load-bearing structure. The method also includes the removal of some of the biostructure`s contents and the loading of a non-biological material into the biostructure. The biostructure is biologically compatible with the host, and preferably is derived from the host, the host`s species or a related species. The loaded biostructure is used directly, or it can be targeted to specific cells, tissues and/or organs within a host. The targeted biostructure can be used to deliver the non-biological material to a specified tissue, organ or cell within a host for diagnostic, therapeutic or other purposes. 11 figs.

Threatened or Threatening? How Ideology Shapes Asylum Seekers’ Immigration Policy Attitudes in Israel and Australia

PubMed Central

Canetti, Daphna; Snider, Keren L. G.; Pedersen, Anne

2016-01-01

Can different political ideologies explain policy preferences regarding asylum seekers? We focus on attitudes regarding governmental policy towards out-group members and suggest that perceptions of threat help to shape these policy attitudes. Study 1 compared public opinion regarding asylum policy in Israel (N = 137) and Australia (N = 138), two countries with restrictive asylum policies and who host a large number of asylum seekers; Study 2, a longitudinal study, was conducted during two different time periods in Israel—before and during the Gaza conflict. Results of both studies showed that threat perceptions of out-group members drive the relationship between conservative political ideologies and support for exclusionary asylum policies among citizens. Perceptions of threat held by members of the host country (the in-group) towards asylum seekers (the out-group) may influence policy formation. The effect of these out-groups threats needs to be critically weighed when considering Israeli and Australian policies towards asylum seekers. PMID:28190933

Threatened or Threatening? How Ideology Shapes Asylum Seekers' Immigration Policy Attitudes in Israel and Australia.

PubMed

Canetti, Daphna; Snider, Keren L G; Pedersen, Anne; Hall, Brian J

2016-12-01

Can different political ideologies explain policy preferences regarding asylum seekers? We focus on attitudes regarding governmental policy towards out-group members and suggest that perceptions of threat help to shape these policy attitudes. Study 1 compared public opinion regarding asylum policy in Israel ( N = 137) and Australia ( N = 138), two countries with restrictive asylum policies and who host a large number of asylum seekers; Study 2, a longitudinal study, was conducted during two different time periods in Israel-before and during the Gaza conflict. Results of both studies showed that threat perceptions of out-group members drive the relationship between conservative political ideologies and support for exclusionary asylum policies among citizens. Perceptions of threat held by members of the host country (the in-group) towards asylum seekers (the out-group) may influence policy formation. The effect of these out-groups threats needs to be critically weighed when considering Israeli and Australian policies towards asylum seekers.

Seasonal dynamics, geographical range size, hosts, genetic diversity and phylogeography of Amblyomma sculptum in Argentina.

PubMed

Tarragona, Evelina L; Sebastian, Patrick S; Saracho Bottero, María N; Martinez, Emilia I; Debárbora, Valeria N; Mangold, Atilio J; Guglielmone, Alberto A; Nava, Santiago

2018-04-27

The aim of this work was to generate knowledge on ecological aspects of Amblyomma sculptum in Argentina, such as seasonal dynamics, geographical range size, hosts, genetic diversity and phylogeography. Adult and immature A. sculptum ticks were collected in different localities of Argentina to know the geographical range size and hosts. The genetic diversity of this tick was studied through analyses of 16S rDNA sequences. To describe the seasonal dynamics, free-living ticks were monthly collected from October 2013 to October 2015. A. sculptum shows a marked ecological preference for Chaco Húmedo eco-region and "Albardones" forest of the great rivers in the wetlands in the Chaco Biogeographical Province, and for Selvas Pedemontanas and Selva Montana in the Yungas Biogeographical Province. This species has low host specificity, and it has large wild and domestic mammals as principal hosts to both immature and adult stages. Amblyomma sculptum is characterized by a one-year life cycle. Larvae peak in early winter, nymphs peaked during mid-spring, and adults during late summer and mid-summer. The genetic divergence was low and the total genetic variability was attributable to differences among populations. This fact could be associated to stochastics process linked to micro-habitat variations that could produce a partial restriction to gene flow among populations. The geographic regions do not contribute much to explain the A. sculptum population genetic structure, with an ancestral haplotype present in most populations, which gives rise to the rest of the haplotypes denoting a rapid population expansion. Copyright © 2018. Published by Elsevier GmbH.

Can reduced predation offset negative effects of sea louse parasites on chum salmon?

PubMed

Peacock, Stephanie J; Connors, Brendan M; Krkosek, Martin; Irvine, James R; Lewis, Mark A

2014-02-07

The impact of parasites on hosts is invariably negative when considered in isolation, but may be complex and unexpected in nature. For example, if parasites make hosts less desirable to predators then gains from reduced predation may offset direct costs of being parasitized. We explore these ideas in the context of sea louse infestations on salmon. In Pacific Canada, sea lice can spread from farmed salmon to migrating juvenile wild salmon. Low numbers of sea lice can cause mortality of juvenile pink and chum salmon. For pink salmon, this has resulted in reduced productivity of river populations exposed to salmon farming. However, for chum salmon, we did not find an effect of sea louse infestations on productivity, despite high statistical power. Motivated by this unexpected result, we used a mathematical model to show how a parasite-induced shift in predation pressure from chum salmon to pink salmon could offset negative direct impacts of sea lice on chum salmon. This shift in predation is proposed to occur because predators show an innate preference for pink salmon prey. This preference may be more easily expressed when sea lice compromise juvenile salmon hosts, making them easier to catch. Our results indicate how the ecological context of host-parasite interactions may dampen, or even reverse, the expected impact of parasites on host populations.

An investigation into the distribution, host-preference and population density of ixodid ticks affecting domestic animals in Bangladesh.

PubMed

Islam, M Khyrul; Alim, M Abdul; Tsuji, Naotoshi; Mondal, M Motahar Hussain

2006-01-01

To study the distribution, host-preference and population density of ixodid ticks in Bangladesh, an attempt was made to collect adult ticks from various host animals in three distinct topographic zones, viz. flood plains, hills and steppe 'Barind'. Five species of ixodid ticks were recorded, namely, Boophilus microplus (56.3%), Haemaphysalis bispinosa (11.3%), Rhipicephalus sanguineus (14.7%), Hyalomma anatolicum anatolicum (15.0%) and Amblyomma testudinarium (2.8%). The data showed that B. microplus occurred predominantly on cattle (42.4%). The other hosts involved were buffaloes (12.5%), goats (25.5%) and pigs (8.2%). H. bispinosa mostly parasitized goats (31.5%) rather than cattle (12.0%) and buffaloes (10.8%). R. sanguineus was principally a dog tick (27.4%) but also parasitized cattle (10.8%) and goats (6.8%). H. a. anatolicum was restricted to cattle (19.2%) and A. testudinarium was found on both cattle (4.4%) and pigs (2.3%). These results indicate that ixodid ticks are not strictly host-specific except for H. a. anatolicum. The population density of these ticks was significantly (p < 0.01) influenced by the changing of seasons. B. microplus, H. bispinosa and R. sanguineus were by far the most widely distributed species; the distribution of H. a. anatolicum was restricted to the steppe 'Barind tract' and A. testudinarium was found in the hilly regions only.

Exploring trophic strategies of exotic caprellids (Crustacea: Amphipoda): Comparison between habitat types and native vs introduced distribution ranges

NASA Astrophysics Data System (ADS)

Ros, Macarena; Tierno de Figueroa, José Manuel; Guerra-García, José Manuel; Navarro-Barranco, Carlos; Lacerda, Mariana Baptista; Vázquez-Luis, Maite; Masunari, Setuko

2014-02-01

The trophic ecology of non-native species is a key aspect to understand their invasion success and the community effects. Despite the important role of caprellid amphipods as trophic intermediates between primary producers and higher levels of marine food webs, there is very little information on their feeding habits. This is the first comprehensive study on the trophic strategies of two co-occurring introduced caprellids in the Spanish coasts: Caprella scaura and Paracaprella pusilla. The diet of 446 specimens of C. scaura and 230 of P. pusilla was analyzed to investigate whether there were differences in the feeding habits in relation to habitat characteristics (natural vs artificial hard substrata), type of host substrata (bryozoans and hydroids) and native vs introduced distribution ranges (Brazil vs Spain). Results revealed differences in diet preferences of the two species that have important implications for their trophic behaviour and showed a limited food overlap, which may favour their coexistence in introduced areas. In general terms, P. pusilla is a predator species, showing preference by crustacean prey in all of its life stages, while C. scaura feeds mainly on detritus. Although no sex-related diet shifts were observed in either of the species, evidence of ontogenetic variation in diet of C. scaura was found, with juveniles feeding on more amount of prey than adults. No diet differences were found between native and introduced populations within the same habitat type. However, P. pusilla exhibited a shift in its diet when different habitats were compared in the same distribution area, and C. scaura showed a flexible feeding behaviour between different host substrata in the same habitat type. This study shows that habitat characteristics at different scales can have greater influence on the feeding ecology of exotic species than different distribution ranges, and support the hypothesis that a switch between feeding strategies depending on habitat characteristics could favour invasion success.

Host suitability and preference of Laricobius nigrinus (Fender) (Coleoptera: Derodontidae): a predatory beetle for potential biological control of Adelges tsugae (Annand) (Homoptera: Adelgidae)

Treesearch

Gabriella Zilahi-Balogh; Scott M. Salom; L. T. Kok

2000-01-01

Laricobius nigrinus (Coleoptera: Derodontidae) is being evaluated as a potential biological control agent of hemlock woolly adelgid (HWA), Adelges tsugae (Homoptera: Adelgidae) Annand in eastern North America. HWA is not considered a pest on western species of hemlock (McClure et al. 1996). A combination of natural enemies and host...

Acceptance and suitability of novel trees for Orthotomicus erosus, an exotic bark beetle in North America

Treesearch

A.J. Walter; R.C. Venette; S.A. Kells

2010-01-01

To predict whether an herbivorous pest insect will establish in a new area, the potential host plants must be known. For invading bark beetles, adults must recognize and accept trees suitable for larval development. The preference-performance hypothesis predicts that adults will select host species that maximize the fitness of their offspring. We tested five species of...

Methods and compositions for simultaneous saccharification and fermentation

DOEpatents

Ingram, Lonnie O'Neal; Zhou, Shengde

2006-04-11

The invention provides compositions and methods for the synergistic degradation of oligosaccharides by endoglucanases. The invention further provides recombinant host cells containing one or more genes encoding endoglucanses which are capable of the synergistic degradation of oligosaccharides. Preferred host cells of the invention are ethanologenic and capable of carrying out simultaneous saccharification and fermentation resulting in the production of ethanol from complex cellulose substrates.

Oviposition Preference and Larval Performance of Anoplophora glabripennis (Coleoptera: Cerambycidae) in Four Eastern North American Hardwood Tree Species

Treesearch

W. D. Morewood; P. R. Neiner; J. R. McNeil; J. C. Sellmer; K. Hoover

2003-01-01

Anoplophora glabripennis (Motschulsky ) is an invasive wood-boring cerambycid beetle that kills hardwood trees. The host range of this species is unusually broad but is not well defined in the available literature and may include tree species that have not been reported as hosts because they have not previously been exposed to the beetle. We...

Combining indoor and outdoor methods for controlling malaria vectors: an ecological model of endectocide-treated livestock and insecticidal bed nets.

PubMed

Yakob, Laith; Cameron, Mary; Lines, Jo

2017-03-13

Malaria is spread by mosquitoes that are increasingly recognised to have diverse biting behaviours. How a mosquito in a specific environment responds to differing availability of blood-host species is largely unknown and yet critical to vector control efficacy. A parsimonious mathematical model is proposed that accounts for a diverse range of host-biting behaviours and assesses their impact on combining long-lasting insecticidal nets (LLINs) with a novel approach to malaria control: livestock treated with insecticidal compounds ('endectocides') that kill biting mosquitoes. Simulations of a malaria control programme showed marked differences across biting ecologies in the efficacy of both LLINs as a stand-alone tool and the combination of LLINs with endectocide-treated cattle. During the intervals between LLIN mass campaigns, concordant use of endectocides is projected to reduce the bounce-back in malaria prevalence that can occur as LLIN efficacy decays over time, especially if replacement campaigns are delayed. Integrating these approaches can also dramatically improve the attainability of local elimination; endectocidal treatment schedules required to achieve this aim are provided for malaria vectors with different biting ecologies. Targeting blood-feeding mosquitoes by treating livestock with endectocides offers a potentially useful complement to existing malaria control programmes centred on LLIN distribution. This approach is likely to be effective against vectors with a wide range of host-preferences and biting behaviours, with the exception of species that are so strictly anthropophilic that most blood meals are taken on humans even when humans are much less available than non-human hosts. Identifying this functional relationship in wild mosquito populations and ascertaining the extent to which it differs, within as well as between species, is a critical next step before targets can be set for employing this novel approach and combination.

North American Lauraceae: terpenoid emissions, relative attraction and boring preferences of redbay ambrosia beetle, Xyleborus glabratus (coleoptera: curculionidae: scolytinae).

PubMed

Kendra, Paul E; Montgomery, Wayne S; Niogret, Jerome; Pruett, Grechen E; Mayfield, Albert E; MacKenzie, Martin; Deyrup, Mark A; Bauchan, Gary R; Ploetz, Randy C; Epsky, Nancy D

2014-01-01

The invasive redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of Raffaelea lauricola, a symbiotic fungus and the etiologic agent of laurel wilt. This lethal disease has caused severe mortality of redbay (Persea borbonia) and swampbay (P. palustris) trees in the southeastern USA, threatens avocado (P. americana) production in Florida, and has potential to impact additional New World species. To date, all North American hosts of X. glabratus and suscepts of laurel wilt are members of the family Lauraceae. This comparative study combined field tests and laboratory bioassays to evaluate attraction and boring preferences of female X. glabratus using freshly-cut bolts from nine species of Lauraceae: avocado (one cultivar of each botanical race), redbay, swampbay, silkbay (Persea humilis), California bay laurel (Umbellularia californica), sassafras (Sassafras albidum), northern spicebush (Lindera benzoin), camphor tree (Cinnamomum camphora), and lancewood (Nectandra coriacea). In addition, volatile collections and gas chromatography-mass spectroscopy (GC-MS) were conducted to quantify terpenoid emissions from test bolts, and electroantennography (EAG) was performed to measure olfactory responses of X. glabratus to terpenoids identified by GC-MS. Significant differences were observed among treatments in both field and laboratory tests. Silkbay and camphor tree attracted the highest numbers of the beetle in the field, and lancewood and spicebush the lowest, whereas boring activity was greatest on silkbay, bay laurel, swampbay, and redbay, and lowest on lancewood, spicebush, and camphor tree. The Guatemalan cultivar of avocado was more attractive than those of the other races, but boring response among the three was equivalent. The results suggest that camphor tree may contain a chemical deterrent to boring, and that different cues are associated with host location and host acceptance. Emissions of α-cubebene, α-copaene, α-humulene, and calamenene were positively correlated with attraction, and EAG analyses confirmed chemoreception of terpenoids by antennal receptors of X. glabratus.

North American Lauraceae: Terpenoid Emissions, Relative Attraction and Boring Preferences of Redbay Ambrosia Beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

PubMed Central

Kendra, Paul E.; Montgomery, Wayne S.; Niogret, Jerome; Pruett, Grechen E.; Mayfield, Albert E.; MacKenzie, Martin; Deyrup, Mark A.; Bauchan, Gary R.; Ploetz, Randy C.; Epsky, Nancy D.

2014-01-01

The invasive redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of Raffaelea lauricola, a symbiotic fungus and the etiologic agent of laurel wilt. This lethal disease has caused severe mortality of redbay (Persea borbonia) and swampbay (P. palustris) trees in the southeastern USA, threatens avocado (P. americana) production in Florida, and has potential to impact additional New World species. To date, all North American hosts of X. glabratus and suscepts of laurel wilt are members of the family Lauraceae. This comparative study combined field tests and laboratory bioassays to evaluate attraction and boring preferences of female X. glabratus using freshly-cut bolts from nine species of Lauraceae: avocado (one cultivar of each botanical race), redbay, swampbay, silkbay (Persea humilis), California bay laurel (Umbellularia californica), sassafras (Sassafras albidum), northern spicebush (Lindera benzoin), camphor tree (Cinnamomum camphora), and lancewood (Nectandra coriacea). In addition, volatile collections and gas chromatography-mass spectroscopy (GC-MS) were conducted to quantify terpenoid emissions from test bolts, and electroantennography (EAG) was performed to measure olfactory responses of X. glabratus to terpenoids identified by GC-MS. Significant differences were observed among treatments in both field and laboratory tests. Silkbay and camphor tree attracted the highest numbers of the beetle in the field, and lancewood and spicebush the lowest, whereas boring activity was greatest on silkbay, bay laurel, swampbay, and redbay, and lowest on lancewood, spicebush, and camphor tree. The Guatemalan cultivar of avocado was more attractive than those of the other races, but boring response among the three was equivalent. The results suggest that camphor tree may contain a chemical deterrent to boring, and that different cues are associated with host location and host acceptance. Emissions of α-cubebene, α-copaene, α-humulene, and calamenene were positively correlated with attraction, and EAG analyses confirmed chemoreception of terpenoids by antennal receptors of X. glabratus. PMID:25007073

Habitat preferences of Boros schneideri (Coleoptera: Boridae) in the natural tree stands of the Białowieża Forest.

PubMed

Gutowski, Jerzy M; Sućko, Krzysztof; Zub, Karol; Bohdan, Adam

2014-01-01

We analyzed habitat requirements of Boros schneideri (Panzer, 1796) (Coleoptera: Boridae) in the natural forests of the continental biogeographical region, using data collected in the Białowieża Forest. This species has been found on the six host trees, but it preferred dead, standing pine trees, characterized by large diameter, moderately moist and moist phloem but avoided trees in sunny locations. It occurred mostly in mesic and wet coniferous forests. This species demonstrated preferences for old tree stands (over 140-yr old), and its occurrence in younger tree-stand age classes (minimum 31-40-yr old) was not significantly different from random distribution. B. schneideri occupied more frequently locations distant from the forest edge, which were less affected by logging. Considering habitat requirements, character of occurrence, and decreasing number of occupied locations in the whole range of distribution, this species can be treated as relict of primeval forests. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

PsOr1, a potential target for RNA interference-based pest management.

PubMed

Zhao, Y Y; Liu, F; Yang, G; You, M S

2011-02-01

Insect pests cause billions of dollars in agricultural losses, and attempts to kill them have resulted in growing threats from insecticide resistance, dietary pesticide pollution and environmental destruction. New approaches to control refractory insect pests are therefore needed. The host-plant preferences of insect pests rely on olfaction and are mediated via a seven transmembrane-domain odorant receptor (Or) family. The present study reports the cloning and characterization of PsOr1, the first candidate member of the Or gene family from Phyllotreta striolata, a devastating beetle pest that causes damage worldwide. PsOr1 is remarkably well conserved with respect to other insect orthologues, including DmOr83b from Drosophila melanogaster. These insect orthologues form an essential non-conventional Or sub-family and may play an important and generalized role in insect olfaction. We designed double-stranded (ds) RNA directly against the PsOr1 gene and exploited RNA interference (RNAi) to control P. striolata. The chemotactic behavioural measurements showed that adult beetles were unable to sense the attractant or repellent odour stimulus after microinjection of dsRNA against PsOr1. Reverse Transcription (RT)-PCR analysis showed specific down-regulation of mRNA transcript levels for this gene. Furthermore, host-plant preference experiments confirmed that silencing PsOr1 by RNAi treatment impaired the host-plant preferences of P. striolata for cruciferous vegetables. These results demonstrate that this insect control approach of using RNAi to target PsOr1 and its orthologues might be effective in blocking host-plant-seeking behaviours in diverse insect pests. The results also support the theory that this unique receptor type plays an essential general role in insect olfaction. © 2010 Fujian Agriculture and Forestry University. Insect Molecular Biology © 2010 The Royal Entomological Society.

Within-plant distribution of Aulacorthum solani (Hemiptera: Aphididae), on various greenhouse plants with implications for control.

PubMed

Jandricic, S E; Mattson, N S; Wraight, S P; Sanderson, J P

2014-04-01

Foxglove aphid, Aulacorthum solani (Kaltenbach) (Hemiptera: Aphididae), has recently undergone a status change from an occasional pest to a serious pest in greenhouses of North America and the United Kingdom. Little nonanecdotal information exists on the ecology of this insect in greenhouse crops. To help improve integrated pest management decisions for A. solani, the within-plant distribution of this pest was explored on a variety of common greenhouse plants in both the vegetative and flowering stage. This aphid generally was found on lower leaves of vegetative plants, but was found higher in the canopy on reproductive plants (on flowers, flower buds, or upper leaves). Aphid numbers were not consistently positively correlated with total leaf surface areas within plant strata across plant species. Thus, the observed differences in preferred feeding sites on vegetative versus flowering plants are possibly a response to differences in nutritional quality of the various host-plant tissues. Despite being anecdotally described as a "stem-feeding aphid," A. solani was rarely found feeding on stems at the population densities established in our tests, with the exception of racemes of scarlet sage (Salvia splendans). Although some previous reports suggested that A. solani prefers to feed on new growth of plants, our results indicate that mature leaves are preferred over growing tips and young leaves. The implications of the within-plant feeding preferences of A. solani populations with respect to both biological and chemical control are discussed.

How does synchrony with host plant affect the performance of an outbreaking insect defoliator?

PubMed

Fuentealba, Alvaro; Pureswaran, Deepa; Bauce, Éric; Despland, Emma

2017-08-01

Phenological mismatch has been proposed as a key mechanism by which climate change can increase the severity of insect outbreaks. Spruce budworm (Choristoneura fumiferana) is a serious defoliator of North American conifers that feeds on buds in the early spring. Black spruce (Picea mariana) has traditionally been considered a poor-quality host plant since its buds open later than those of the preferred host, balsam fir (Abies balsamea). We hypothesize that advancing black spruce budbreak phenology under a warmer climate would improve its phenological synchrony with budworm and hence increase both its suitability as a host plant and resulting defoliation damage. We evaluated the relationship between tree phenology and both budworm performance and tree defoliation by placing seven cohorts of budworm larvae on black spruce and balsam fir branches at different lags with tree budburst. Our results show that on both host plants, spruce budworm survival and pupal mass decrease sharply when budbreak occurs prior to larval emergence. By contrast, emergence before budbreak decreases survival, but does not negatively impact growth or reproductive output. We also document phytochemical changes that occur as needles mature and define a window of opportunity for the budworm. Finally, larvae that emerged in synchrony with budbreak had the greatest defoliating effect on black spruce. Our results suggest that in the event of advanced black spruce phenology due to climate warming, this host species will support better budworm survival and suffer increased defoliation.

Host-specificity among abundant and rare taxa in the sponge microbiome.

PubMed

Reveillaud, Julie; Maignien, Loïs; Murat Eren, A; Huber, Julie A; Apprill, Amy; Sogin, Mitchell L; Vanreusel, Ann

2014-06-01

Microbial communities have a key role in the physiology of the sponge host, and it is therefore essential to understand the stability and specificity of sponge-symbiont associations. Host-specific bacterial associations spanning large geographic distance are widely acknowledged in sponges. However, the full spectrum of specificity remains unclear. In particular, it is not known whether closely related sponges host similar or very different microbiota over wide bathymetric and geographic gradients, and whether specific associations extend to the rare members of the sponge microbiome. Using the ultra-deep Illumina sequencing technology, we conducted a comparison of sponge bacterial communities in seven closely related Hexadella species with a well-resolved host phylogeny, as well as of a distantly related sponge Mycale. These samples spanned unprecedentedly large bathymetric (15-960 m) gradients and varying European locations. In addition, this study included a bacterial community analysis of the local background seawater for both Mycale and the widespread deep-sea taxa Hexadella cf. dedritifera. We observed a striking diversity of microbes associated with the sponges, spanning 47 bacterial phyla. The data did not reveal any Hexadella microbiota co-speciation pattern, but confirmed sponge-specific and species-specific host-bacteria associations, even within extremely low abundant taxa. Oligotyping analysis also revealed differential enrichment preferences of closely related Nitrospira members in closely related sponges species. Overall, these results demonstrate highly diverse, remarkably specific and stable sponge-bacteria associations that extend to members of the rare biosphere at a very fine phylogenetic scale, over significant geographic and bathymetric gradients.

A Contribution to the Bionomics of the Tabanidae (Diptera) of Algonquin Park, Ontario: Seasonal Distribution, Habitat Preferences, and Biting Records,

DTIC Science & Technology

which influence the extent to which certain species are found biting various host species are discussed in relation to the tabanid population of the...serious pest problems. The analysis of collections of tabanids from carbon dioxide-baited traps placed in different habitat types revealed several patterns... tabanids attracted to or biting man, moose, and white-tailed deer are presented. These lists constitute the first extensive records of the Tabanidae attracted to the Cervidae in the boreal forest region of Canada. (Author)

Differential genetic regulation of motor activity and anxiety-related behaviors in mice using an automated home cage task.

PubMed

Kas, Martien J H; de Mooij-van Malsen, Annetrude J G; Olivier, Berend; Spruijt, Berry M; van Ree, Jan M

2008-08-01

Traditional behavioral tests, such as the open field test, measure an animal's responsiveness to a novel environment. However, it is generally difficult to assess whether the behavioral response obtained from these tests relates to the expression level of motor activity and/or to avoidance of anxiogenic areas. Here, an automated home cage environment for mice was designed to obtain independent measures of motor activity levels and of sheltered feeding preference during three consecutive days. Chronic treatment with the anxiolytic drug chlordiazepoxide (5 and 10 mg/kg/day) in C57BL/6J mice reduced sheltered feeding preference without altering motor activity levels. Furthermore, two distinct chromosome substitution strains, derived from C57BL/6J (host strain) and A/J (donor strain) inbred strains, expressed either increased sheltering preference in females (chromosome 15) or reduced motor activity levels in females and males (chromosome 1) when compared to C57BL/6J. Longitudinal behavioral monitoring revealed that these phenotypic differences maintained after adaptation to the home cage. Thus, by using new automated behavioral phenotyping approaches, behavior can be dissociated into distinct behavioral domains (e.g., anxiety-related and motor activity domains) with different underlying genetic origin and pharmacological responsiveness.

Nutrition versus defense: Why Myzus persicae (green peach aphid) prefers and performs better on young leaves of cabbage

PubMed Central

Cao, He-He; Zhang, Zhan-Feng; Wang, Xiao-Feng

2018-01-01

Plant leaves of different ages differ in nutrients and toxic metabolites and thus exhibit various resistance levels against insect herbivores. However, little is known about the influence of leaf ontogeny on plant resistance to phloem-feeding insects. In this study, we found that the green peach aphid, Myzus persicae, preferred to settle on young cabbage leaves compared with mature or old leaves, although young leaves contained the highest concentration of glucosinolates. Furthermore, aphids feeding on young leaves had higher levels of glucosinolates in their body, but aphids performed better on young leaves in terms of body weight and population growth. Phloem sap of young leaves had higher amino acid:sugar molar ratio than mature leaves, and aphids feeding on young leaves showed two times longer phloem feeding time and five times more honeydew excretion than on other leaves. These results indicate that aphids acquired the highest amount of nutrients and defensive metabolites when feeding on young cabbage leaves that are strong natural plant sinks. Accordingly, we propose that aphids generally prefer to obtain more nutrition rather than avoiding host plant defense, and total amount of nutrition that aphids could obtain is significantly influenced by leaf ontogeny or source-sink status of feeding sites. PMID:29684073

Transmission of Helminths between Species of Ruminants in Austria Appears More Likely to Occur than Generally Assumed

PubMed Central

Winter, Jakob; Rehbein, Steffen; Joachim, Anja

2018-01-01

Helminth infections of the gastrointestinal tract and lungs can lead to devastating economical losses to the pastoral based animal production. Farm animals can suffer from malnutrition, tissue damage, and blood loss resulting in impaired production traits and reproduction parameters. In Austria, pastures grazed by sheep, goats, and cattle overlap with the habitats of several species of wild cervids (roe deer, red deer, sika deer, and fallow deer) and bovids (mouflon, chamois, and ibex), and transmission of parasites between different ruminant species seems likely. A complete and updated overview on the occurrence of helminths of domestic and wild ruminants in Austria is presented. Based on these data, intersections of the host spectrum of the determined parasites were depicted. The “liability index” was applied to identify the ruminant species, which most likely transmit parasites between each other. A degree for host specificity was calculated for each parasite species based on the average taxonomic distance of their host species. Of the 73 identified helminth species 42 were identified as generalists, and 14 transmission experiments supported the assumed broad host specificity for 14 generalists and 1 specialist helminth species. Overall, 61 helminths were found to infect more than one host species, and 4 were found in all 10 ruminant species investigated. From these analyses, it can be concluded that a number of helminth parasites of the gastrointestinal tract and the lungs are potentially transmitted between domestic and wild ruminants in Austria. For some parasites and host species, experimental evidence is in support for possible transmission, while for other such studies are lacking. Host preference of different genotypes of the same parasite species may have a confounding effect on the evaluation of cross-transmission, but so far this has not been evaluated systematically in helminths in Austria. Further studies focusing on experimental cross-transmission and genetic characterization are needed to define the potential consequences for the epidemiology of those parasites, animal welfare, and economic impact. PMID:29662884

Host-Mediated Effects of Semipersistently Transmitted Squash Vein Yellowing Virus on Sweetpotato Whitefly (Hemiptera: Aleyrodidae) Behavior and Fitness.

PubMed

Shrestha, Deepak; McAuslane, Heather J; Adkins, Scott T; Smith, Hugh A; Dufault, Nicholas; Colee, James; Webb, Susan E

2017-08-01

Plant viruses may indirectly affect insect vector behavior and fitness via a shared host plant. Here, we evaluated the host-mediated effects of Squash vein yellowing virus (SqVYV) on the behavior and fitness of its whitefly vector, Bemisia tabaci (Gennadius) Middle East-Asia Minor 1, formerly biotype B. Alighting, settling, and oviposition behavioral assays were conducted on infected and mock-inoculated squash (Cucurbita pepo L.) and watermelon [Citrullus lanatus (Thunb) Matsum and Nakai] plants. Developmental time of immature stages, adult longevity, and fecundity were measured on infected and mock-inoculated squash plants. For adult longevity and fecundity, whiteflies were reared on infected and mock-inoculated squash plants to determine the effects of nymphal rearing host on the adult stage. More whiteflies alighted and remained settled on infected squash than on mock-inoculated squash 0.25, 1, 8, and 24 h after release. No such initial preference was observed on watermelon plants, but by 8 h after release, more whiteflies were found on mock-inoculated watermelon plants than on infected plants. Whiteflies laid approximately six times more eggs on mock-inoculated watermelon than on infected watermelon; however, no differences were observed on squash. Development from egg to adult emergence was 3 d shorter on infected than mock-inoculated squash plants. Females lived 25% longer and had higher fecundity on infected squash plants than on mock-inoculated plants, regardless of infection status of the rearing host. The host-mediated effects of SqVYV infection on whitefly behavior differ on two cucurbit host plants, suggesting the potential for more rapid spread of the virus within watermelon fields. © 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.

Liana habitat and host preferences in northern temperate forests

USGS Publications Warehouse

Leicht-Young, S. A.; Pavlovic, N.B.; Frohnapple, K.J.; Grundel, R.

2010-01-01

Lianas and other climbers are important ecological and structural components of forest communities. Like other plants, their abundance in a given habitat depends on a variety of factors, such as light, soil moisture and nutrients. However, since lianas require external support, host tree characteristics also influence their distribution. Lianas are conspicuous life forms in tropical regions, but in temperate areas, where they are less prominent, little is known about factors that control their distributions in these forests. We surveyed the climbing plant species in 20 mature (100 years and greater) forested habitats in the Midwest USA at a variety of levels from simple presence/absence, to ground layer abundances, to those species that had ascended trees. We also examined attributes of the tree species with climbers attached to them. Using cluster analysis, we distinguished five different tree communities in our survey locations. We determined that 25% of the trees we surveyed had one or more lianas attached to it, with Parthenocissus quinquefolia (Virginia creeper) the most common climbing species encountered. Canopy cover and soil attributes both influenced climber species presence/absence and ground layer climber abundance. The proportion of liana species of a given climbing type (roots, stem twiner, tendril climber) was significantly related to the DBH of the host tree, with more root climbers and fewer stem and tendril climbers on large trees. In general, the DBH of climbing lianas had a significant positive relationship to the DBH of the host tree; however this varied by the identity of the liana and the tree species. The greater the DBH of the host tree, the higher the probability that it was colonized by one or more lianas, with tree species such as Pinus banksiana (jack pine) and Quercus alba (white oak) being more susceptible to liana colonization than others. Finally, some liana species such as Celastrus scandens (American bittersweet) showed a preference for certain tree species (i.e., P. banksiana) as hosts. The information obtained about the relationship between the tree and climber community in this study provides insight into some of the factors that influence liana distributions in understudied temperate forest habitats and how lianas contribute to the structure of these mature forests. In addition, these data can provide a point of comparison to other liana communities in both temperate and tropical regions.

Host Range Testing of Diaphorencyrtus aligarhensis (Hymenoptera: Encyrtidae) for Use in Classical Biological Control of Diaphorina citri (Hemiptera: Liviidae) in California.

PubMed

Bistline-East, Allison; Pandey, Raju; Kececi, Mehmet; Hoddle, Mark S

2015-06-01

Host range tests for Diaphorencyrtus aligarhensis (Shafee, Alam, & Agarwal) (Hymenoptera: Encyrtidae), an endoparasitoid of Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), sourced from Punjab Pakistan, were conducted in quarantine at the University of California, Riverside, CA. Seven nontarget psyllid species representing four psyllid families were exposed to mated D. aligarhensis females in four different treatment types: 1) short sequential no-choice treatments, 2) prolonged sequential no-choice treatments, 3) prolonged no-choice static treatments, and 4) choice treatments. Selection of nontarget psyllid species was based on phylogenetic proximity to D. citri, likelihood of being encountered by D. aligarhensis in the prospective release areas in California, and psyllid species in biological control of invasive weeds. D. aligarhensis exhibited high host affinity to D. citri, and only parasitized one nontarget species, the pestiferous potato psyllid, Bactericera cockerelli (Sulc), at low levels (<14%). Based on the results of this study, we conclude that D. aligarhensis has a narrow host range and exhibits a high level of host specificity, as it shows a significant attack preference for the target pest, D. citri. Results presented here suggest D. aligarhensis poses minimal risk to nontarget psyllid species in California. © 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.

The Roles of Parasitoid Foraging for Hosts, Food and Mates in the Augmentative Control of Tephritidae.

PubMed

Sivinski, John; Aluja, Martin

2012-07-20

Ultimately, the success of augmentative fruit fly biological control depends upon the survival, dispersal, attack rate and multi-generational persistence of mass-reared parasitoids in the field. Foraging for hosts, food and mates is fundamental to the above and, at an operational level, the choice of the parasitoid best suited to control a particular tephritid in a certain environment, release rate estimates and subsequent monitoring of effectiveness. In the following we review landscape-level and microhabitat foraging preferences, host/fruit ranges, orientation through environmental cues, host vulnerabilities/ovipositor structures, and inter and intraspecific competition. We also consider tephritid parasitoid mating systems and sexual signals, and suggest the directions of future research.

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.

Host preference of the vector beetle, host resistance, and expanding patterns of Japanese oak wilt in a stand

Treesearch

Kazuyoshi Futai; Hiroaki Kiku; Hong-ye Qi; Hagus Tarn; Yuko Takeuchi; Michimasa Yamasaki

2012-01-01

Since the early 1980s, an epidemic forest disease, Japanese Oak Wilt (JOW), has been spreading from coastal areas along the Sea of Japan to the interior of Honshu island and has been devastating huge areas of forests by killing an enormous number of oak trees in urban fringe mountains, gardens, and parks. The disease is caused by a fungus, Raffaelea...

Host Preference of Megacopta cribraria (Hemiptera: Plataspidae) on Selected Edible Beans and Soybean.

PubMed

Blount, J L; Buntin, G D; Sparks, A N

2015-06-01

Megacopta cribraria (F.) (Hemiptera: Plataspidae) is an Old World pest of legumes in Asia. Since its 2009 discovery in Georgia, it has become an economic pest of soybeans in the southeastern United States. The objective of this study was to determine the host preference of M. cribraria on edible legumes that might incur economic damage from injury of this pest. From 2012 to 2013 choice, no-choice, and field trials were conducted to evaluate the host suitability of several beans of commercial interest including pinto bean, lima bean, winter pea, and black-eyed pea. Choice and no-choice studies were conducted under greenhouse conditions. Plants in greenhouse trials were infested with adults and egg masses collected from kudzu and soybean and monitored for ∼2 wk. Field trials were allowed to be infested by naturally occurring M. cribraria populations. Sweep and whole plant counts of adults, egg masses, and nymphs were used to quantify field infestations. The legume crops found to be suitable developmental hosts are soybean, edamame, and pigeon pea. Low levels of development were seen on fava bean and none on the remaining entries. © 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.

Host-plant effects on larval survival of a salicin-using leaf beetle Chrysomela aeneicollis Schaeffer (Coleoptera: Chrysomelidae).

PubMed

Rank, Nathan Egan

1994-04-01

Several species of willow leaf beetles use hostplant salicin to produce a defensive secretion that consists of salicylaldehyde. Generalist arthropod predators such as ants, ladybird beetles, and spiders are repelled by this secretion. The beetle larvae produce very little secretion when they feed on willows that lack salicylates, and salicin-using beetles prefer salicylate-rich willows over salicylate-poor ones. This preference may exist because the larvae are better defended against natural enemies on salicylate-rich willows. If this is true, the larvae should survive longer on those willows in nature. However, this prediction has not been tested. I determined the larval growth and survival of Chrysomela aeneicollis (Coleoptera: Chrysomelidae) on five willow species (Salix boothi, S. drummondiana, S. geyeriana, S. lutea, and S. orestera). These species differed in their salicylate chemistries and in leaf toughness but not in water content. The water content varied among the individual plants. Larval growth of C. aeneicollis did not differ among the five species in the laboratory, but it varied among the individual plants and it was related to the water content. In the field, C. aeneicollis larvae developed equally rapidly on the salicylate-poor S. lutea and on the salicylate-rich S. orestera. Larval survival was greater on S. orestera than on S. lutea in one year (1986), but there was no difference between them during three succeeding years. In another survivorship experiment, larval survival was low on the medium-salicylate S. geyeriana, but high on the salicylate-poor S. boothi and on S. orestera. Larval survival in the field was related to the larval growth and water content that had been previously measured in the laboratory. These results showed that the predicted relationship between the host plant chemistry and larval survival did not usually exist for C. aeneicollis. One possible reason for this was that the most important natural enemies were specialist predators that were unaffected by the host-derived defensive secretion. One specialist predator, Symmorphus cristatus (Hymenoptera: Eumenidae), probably caused much of the mortality observed in this study. I discuss the importance of other specialist predators to salicin-using leaf beetles.

Nocturnal activities and host preferences of Phlebotomus orientalis in extra-domestic habitats of Kafta-Humera lowlands, Kala-azar endemic, Northwest Ethiopia.

PubMed

Lemma, Wossenseged; Tekie, Habte; Abassi, Ibrahim; Balkew, Meshesha; Gebre-Michael, Teshome; Warburg, Alon; Hailu, Asrat

2014-12-17

Phlebotomus orientalis feeds on a variety of wild and domestic animals and transmits Leishmania donovani from hitherto unknown reservoir hosts to humans in extra-domestic habitats in the Metema-Humera lowlands. The aim of this study was to determine the nocturnal activities of P. orientalis and its preferred blood meal hosts. Collections of Phlebotomus orientalis were made by using CDC light traps to determine the density as P. orientalis/hour CDC trap and preference to rodents by using Turner's traps in agricultural fields, animal shelters and thickets of Acacia seyal in Baeker site-1 and Gelanzeraf site-2. The blood meal sources were detected by Reverse Line Blot (RLB) of cytochrome b polymerase chain reaction (PCR) amplification in August, 2012 from collections of sand flies in thickets of A. seyal (March 2011) and dense mixed forest (July 2011) in Baeker site 1. RLB PCR involved first amplification of animal specific sequences of cytochrome b using PCR techniques. Then the amplified sequence was hybridized with 11 species-specific probes for domestic animals adsorbed on nitrocellulose membrane for calorimetric color detection. A total of 6,083 P. orientalis (2,702 males and 3,381 females) were collected at hourly intervals using 22 CDC traps from January to May 2013. The peak activities of P. orientalis were at 1.00 a.m (134.0 ± 7.21) near animal shelters, 3.00 a.m (66.33 ± 46.40) in agricultural fields and 21:00 pm (40.6 ± 30.06) in thickets of A. seyal. This species was not attracted to the different species of rodents in trials carried out in March and April 2013. RLB PCR identified 7 human (28%), 9 mixed (human and cattle) (36%) and 2 cattle (8%) blood meals while 7 were unknown (28%). Female P. orientalis can bite humans in extra-domestic habitats of Kafta-Humera lowlands at any hour of the night with peak biting after midnight.

Quantifying Heterogeneity in Host-Vector Contact: Tsetse (Glossina swynnertoni and G. pallidipes) Host Choice in Serengeti National Park, Tanzania

PubMed Central

Auty, Harriet; Cleaveland, Sarah; Malele, Imna; Masoy, Joseph; Lembo, Tiziana; Bessell, Paul; Torr, Stephen; Picozzi, Kim; Welburn, Susan C.

2016-01-01

Background Identifying hosts of blood-feeding insect vectors is crucial in understanding their role in disease transmission. Rhodesian human African trypanosomiasis (rHAT), also known as acute sleeping sickness is caused by Trypanosoma brucei rhodesiense and transmitted by tsetse flies. The disease is commonly associated with wilderness areas of east and southern Africa. Such areas hold a diverse range of species which form communities of hosts for disease maintenance. The relative importance of different wildlife hosts remains unclear. This study quantified tsetse feeding preferences in a wilderness area of great host species richness, Serengeti National Park, Tanzania, assessing tsetse feeding and host density contemporaneously. Methods Glossina swynnertoni and G. pallidipes were collected from six study sites. Bloodmeal sources were identified through matching Cytochrome B sequences amplified from bloodmeals from recently fed flies to published sequences. Densities of large mammal species in each site were quantified, and feeding indices calculated to assess the relative selection or avoidance of each host species by tsetse. Results The host species most commonly identified in G. swynnertoni bloodmeals, warthog (94/220), buffalo (48/220) and giraffe (46/220), were found at relatively low densities (3-11/km2) and fed on up to 15 times more frequently than expected by their relative density. Wildebeest, zebra, impala and Thomson’s gazelle, found at the highest densities, were never identified in bloodmeals. Commonly identified hosts for G. pallidipes were buffalo (26/46), giraffe (9/46) and elephant (5/46). Conclusions This study is the first to quantify tsetse host range by molecular analysis of tsetse diet with simultaneous assessment of host density in a wilderness area. Although G. swynnertoni and G. pallidipes can feed on a range of species, they are highly selective. Many host species are rarely fed on, despite being present in areas where tsetse are abundant. These feeding patterns, along with the ability of key host species to maintain and transmit T. b. rhodesiense, drive the epidemiology of rHAT in wilderness areas. PMID:27706167

Host-Cell Survival and Death During Chlamydia Infection

PubMed Central

Ying, Songmin; Pettengill, Matthew; Ojcius, David M.; Häcker, Georg

2008-01-01

Different Chlamydia trachomatis strains are responsible for prevalent bacterial sexually-transmitted disease and represent the leading cause of preventable blindness worldwide. Factors that predispose individuals to disease and mechanisms by which chlamydiae cause inflammation and tissue damage remain unclear. Results from recent studies indicate that prolonged survival and subsequent death of infected cells and their effect on immune effector cells during chlamydial infection may be important in determining the outcome. Survival of infected cells is favored at early times of infection through inhibition of the mitochondrial pathway of apoptosis. Death at later times displays features of both apoptosis and necrosis, but pro-apoptotic caspases are not involved. Most studies on chlamydial modulation of host-cell death until now have been performed in cell lines. The consequences for pathogenesis and the immune response will require animal models of chlamydial infection, preferably mice with targeted deletions of genes that play a role in cell survival and death. PMID:18843378

A comparative study of the spectroscopic properties of Mn4+ in the garnet Y2Mg3Ge3O12 and the commercial Mg28Ge7.55O32F15.04 phosphor

NASA Astrophysics Data System (ADS)

Srivastava, A. M.

2018-05-01

The spectroscopic properties of Mn4+ (3 d3) ions in the garnet Y2Mg3Ge3O12 and in the commercial Mg28Ge7.55O32F15.04 (MFG) phosphors are compared. We find that despite the differences in host crystal composition and crystal structures, the 4A2g→ 4T1g and 2Eg→4A2g optical transitions of the Mn4+ ion occur at similar energies. We provide some insights into the nature of chemical bonding that is responsible for the observed similarity in the spectroscopic data. Additionally, discussion is given to the site preference of the Mn4+ ion in the MFG host crystal.

Yersinia pestis and Yersinia pseudotuberculosis infection: a regulatory RNA perspective

PubMed Central

Martínez-Chavarría, Luary C.; Vadyvaloo, Viveka

2015-01-01

Yersinia pestis, responsible for causing fulminant plague, has evolved clonally from the enteric pathogen, Y. pseudotuberculosis, which in contrast, causes a relatively benign enteric illness. An ~97% nucleotide identity over 75% of their shared protein coding genes is maintained between these two pathogens, leaving much conjecture regarding the molecular determinants responsible for producing these vastly different disease etiologies, host preferences and transmission routes. One idea is that coordinated production of distinct factors required for host adaptation and virulence in response to specific environmental cues could contribute to the distinct pathogenicity distinguishing these two species. Small non-coding RNAs that direct posttranscriptional regulation have recently been identified as key molecules that may provide such timeous expression of appropriate disease enabling factors. Here the burgeoning field of small non-coding regulatory RNAs in Yersinia pathogenesis is reviewed from the viewpoint of adaptive colonization, virulence and divergent evolution of these pathogens. PMID:26441890

Evaluation method for the potential functionome harbored in the genome and metagenome.

PubMed

Takami, Hideto; Taniguchi, Takeaki; Moriya, Yuki; Kuwahara, Tomomi; Kanehisa, Minoru; Goto, Susumu

2012-12-12

One of the main goals of genomic analysis is to elucidate the comprehensive functions (functionome) in individual organisms or a whole community in various environments. However, a standard evaluation method for discerning the functional potentials harbored within the genome or metagenome has not yet been established. We have developed a new evaluation method for the potential functionome, based on the completion ratio of Kyoto Encyclopedia of Genes and Genomes (KEGG) functional modules. Distribution of the completion ratio of the KEGG functional modules in 768 prokaryotic species varied greatly with the kind of module, and all modules primarily fell into 4 patterns (universal, restricted, diversified and non-prokaryotic modules), indicating the universal and unique nature of each module, and also the versatility of the KEGG Orthology (KO) identifiers mapped to each one. The module completion ratio in 8 phenotypically different bacilli revealed that some modules were shared only in phenotypically similar species. Metagenomes of human gut microbiomes from 13 healthy individuals previously determined by the Sanger method were analyzed based on the module completion ratio. Results led to new discoveries in the nutritional preferences of gut microbes, believed to be one of the mutualistic representations of gut microbiomes to avoid nutritional competition with the host. The method developed in this study could characterize the functionome harbored in genomes and metagenomes. As this method also provided taxonomical information from KEGG modules as well as the gene hosts constructing the modules, interpretation of completion profiles was simplified and we could identify the complementarity between biochemical functions in human hosts and the nutritional preferences in human gut microbiomes. Thus, our method has the potential to be a powerful tool for comparative functional analysis in genomics and metagenomics, able to target unknown environments containing various uncultivable microbes within unidentified phyla.

MAINTENANCE OF ECOLOGICALLY SIGNIFICANT GENETIC VARIATION IN THE TIGER SWALLOWTAIL BUTTERFLY THROUGH DIFFERENTIAL SELECTION AND GENE FLOW.

PubMed

Bossart, J L; Scriber, J M

1995-12-01

Differential selection in a heterogeneous environment is thought to promote the maintenance of ecologically significant genetic variation. Variation is maintained when selection is counterbalanced by the homogenizing effects of gene flow and random mating. In this study, we examine the relative importance of differential selection and gene flow in maintaining genetic variation in Papilio glaucus. Differential selection on traits contributing to successful use of host plants (oviposition preference and larval performance) was assessed by comparing the responses of southern Ohio, north central Georgia, and southern Florida populations of P. glaucus to three hosts: Liriodendron tulipifera, Magnolia virginiana, and Prunus serotina. Gene flow among populations was estimated using allozyme frequencies from nine polymorphic loci. Significant genetic differentiation was observed among populations for both oviposition preference and larval performance. This differentiation was interpreted to be the result of selection acting on Florida P. glaucus for enhanced use of Magnolia, the prevalent host in Florida. In contrast, no evidence of population differentiation was revealed by allozyme frequencies. F ST -values were very small and Nm, an estimate of the relative strengths of gene flow and genetic drift, was large, indicating that genetic exchange among P. glaucus populations is relatively unrestricted. The contrasting patterns of spatial differentiation for host-use traits and lack of differentiation for electrophoretically detectable variation implies that differential selection among populations will be counterbalanced by gene flow, thereby maintaining genetic variation for host-use traits. © 1995 The Society for the Study of Evolution.

Correlations between adult mimicry and larval host plants in ithomiine butterflies.

PubMed

Willmott, Keith R; Mallet, James

2004-08-07

The apparent paradox of multiple coexisting wing pattern mimicry 'rings' in tropical butterflies has been explained as a result of microhabitat partitioning in adults. However, very few studies have tested this hypothesis. In neotropical forests, ithomiine butterflies dominate and display the richest diversity of mimicry rings. We show that co-mimetic species occupy the same larval host-plant species significantly more often than expected in two out of five communities that we surveyed; in one of these, the effect remains significant after phylogenetic correction. This relationship is most probably a result of a third correlated variable, such as microhabitat. Host-plant microhabitat may constrain adult movement, or host-plant choice may depend on butterfly microhabitat preferences and mimicry associations. This link between mimicry and host plant could help explain some host-plant and mimicry shifts, which have been important in the radiation of this speciose tropical group.

Local Swift-BAT active galactic nuclei prefer circumnuclear star formation

NASA Astrophysics Data System (ADS)

Lutz, D.; Shimizu, T.; Davies, R. I.; Herrera-Camus, R.; Sturm, E.; Tacconi, L. J.; Veilleux, S.

2018-01-01

We use Herschel data to analyze the size of the far-infrared 70 μm emission for z < 0.06 local samples of 277 hosts of Swift-BAT selected active galactic nuclei (AGN), and 515 comparison galaxies that are not detected by BAT. For modest far-infrared luminosities 8.5 10.5 (star formation rates ≳6 M⊙ yr-1), possibly because these are typically reached in more compact regions. Full Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A9

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

Löfling, Jonas; Michael Lyi, Sangbom; Parrish, Colin R.

Feline panleukopenia virus (FPV) is a pathogen whose canine-adapted form (canine parvovirus (CPV)) emerged in 1978. These viruses infect by binding host transferrin receptor type-1 (TfR), but also hemagglutinate erythrocytes. We show that hemagglutination involves selective recognition of the non-human sialic acid N-glycolylneuraminic acid (Neu5Gc) but not N-acetylneuraminic acid (Neu5Ac), which differs by only one oxygen atom from Neu5Gc. Overexpression of α2-6 sialyltransferase did not change binding, indicating that both α2-3 and α2-6 linkages are recognized. However, Neu5Gc expression on target cells did not enhance CPV or FPV infection in vitro. Thus, the conserved Neu5Gc-binding preference of these viruses likelymore » plays a role in the natural history of the virus in vivo. Further studies must clarify relationships between virus infection and host Neu5Gc expression. As a first step, we show that transcripts of CMAH (which generates Neu5Gc from Neu5Ac) are at very low levels in Western dog breed cells. - Highlights: ► Feline and canine parvoviruses recognize Neu5Gc but not Neu5Ac, which differ by one oxygen atom. ► The underlying linkage of these sialic acids does not affect recognition. ► Induced Neu5Gc expression on target cells that normally express Neu5Ac did not enhance infection. ► Thus, the conserved binding preference plays an important yet unknown role in in vivo infections. ► Population and breed variations in Neu5Gc expression occur, likely by regulating the gene CMAH.« less

Black and Garlic Mustard Plants Are Highly Suitable for the Development of Two Native Pierid Butterflies.

PubMed

Heinen, Robin; Gols, Rieta; Harvey, Jeffrey A

2016-04-22

In multivoltine insects that oviposit and develop on short-lived plants, different herbivore generations across a growing season often exploit different plant species. Here, we compare the development time, pupal mass, and survival of two closely related oligophagous herbivore species on two species of brassicaceous plants that grow in different habitats and which exhibit little overlap in temporal growth phenology. In central Europe, the green-veined white butterfly, Pieris napi L., is bivoltine, whereas the small cabbage white butterfly, Pieris rapae L., has two to three generations a year. Moreover, P. napi is primarily found in moist, open (e.g., meadow), and forest habitats, whereas P. rapae prefers drier, open habitats. Both butterflies were reared on Garlic mustard (Alliaria petiolata), which is shade-tolerant and grows early in spring in forest undergrowth, and Black mustard (Brassica nigra), which prefers open disturbed habitats and is most common in summer. Both host plant species differ in other traits such as secondary chemistry. We hypothesized that, owing to habitat preference, P. napi would develop equally well on both plants but that P. rapae would perform better on B. nigra The results provide partial support for this hypothesis, as both herbivores performed equally well on A. petiolata and B. nigra However, there were differences in these parameters that were species-specific: on both plants P. rapae developed faster and had larger pupae than P. napi Our results show that specialized herbivores can exploit different species of related plants that grow at different times of the season, enabling them to have multiple generations. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Amino acid metabolism in tumour-bearing mice.

PubMed Central

Rivera, S; Azcón-Bieto, J; López-Soriano, F J; Miralpeix, M; Argilés, J M

1988-01-01

Mice bearing the Lewis lung carcinoma showed a high tumour glutaminase activity and significantly higher concentrations of most amino acids than in both the liver and the skeletal muscle of the host. Tumour tissue slices showed a marked preference for glutamine, especially for oxidation of its skeleton to CO2. It is proposed that the metabolism of this particular carcinoma is focused on amino acid degradation, glutamine being its preferred substrate. PMID:3342022

Effect of starvation on vein preference of whitefly (Bemisia tabaci) on chilli as host plant

NASA Astrophysics Data System (ADS)

Siti Sakinah, A.; Mohamad Roff M., N.; Idris, A. B.

2014-09-01

The whitefly, Bemisia tabaci (Gennadius), is a cosmopolitan pest of horticultural crops. It caused serious damaged to the plants by feeding on plant saps as direct damage and transmit virus as indirect damage. Vein preferences of both female and male whitefly (WF) on chilli plant were recorded using Dinolite, a portable microscope, under laboratory conditions. WF adults of both sexes were starved for 2 and 4 hours before used for observation while no starvation for control individual (treatment). Results showed that both female and male preferred to feed on secondary veins rather than lamina, midrib and vein. From the result of whitefly preferred target site, hopefully this information will help to improve control tactics in WF management.

Odor, Not Performance, Dictates Bemisia tabaci's Selection between Healthy and Virus Infected Plants

PubMed Central

Chen, Gong; Su, Qi; Shi, Xiaobin; Liu, Xin; Peng, Zhengke; Zheng, Huixin; Xie, Wen; Xu, Baoyun; Wang, Shaoli; Wu, Qingjun; Zhou, Xuguo; Zhang, Youjun

2017-01-01

Although, insect herbivores are generally thought to select hosts that favor the fitness of their progeny, this “mother-knows-best” hypothesis may be challenged by the presence of a plant virus. Our previous study showed that the whitefly, Bemisia tabaci, the obligate vector for transmitting Tomato yellow leaf curl virus (TYLCV), preferred to settle and oviposit on TYLCV-infected rather than healthy host plant, Datura stramonium. The performances of B. tabaci larvae and adults were indeed improved on virus-infected D. stramonium, which is consistent with “mother-knows-best” hypothesis. In this study, B. tabaci Q displayed the same preference to settle and oviposit on Tomato spotted wilt virus (TSWV)-infected host plants, D. stramonium and Capsicum annuum, respectively. As a non-vector of TSWV, however, insect performance was impaired since adult body size, longevity, survival, and fecundity were reduced in TSWV infected D. stramonium. This appears to be an odor-mediated behavior, as plant volatile profiles are modified by viral infection. Infected plants have reduced quantities of o-xylene and α-pinene, and increased levels of phenol and 2-ethyl-1-hexanol in their headspace. Subsequent behavior experiments showed that o-xylene and α-pinene are repellant, while phenol and 2-ethyl-1-hexanol are attractive. This indicates that the preference of B. tabaci for virus-infected plants is modulated by the dynamic changes in the volatile profiles rather than the subsequent performances on virus-infected plants. PMID:28360861

Effects of root herbivory by nematodes on the performance and preference of a leaf-infesting generalist aphid depend on nitrate fertilization.

PubMed

Kutyniok, Magdalene; Persicke, Marcus; Müller, Caroline

2014-02-01

The performance and behavior of herbivores is strongly affected by the quality of their host plants, which is determined by various environmental conditions. We investigated the performance and preference of the polyphagous shoot-infesting aphid Myzus persicae on the host-plant Arabidopsis thaliana in a two-factorial design in which nitrate fertilization was varied by 33 %, and the root-infesting cyst-nematode Heterodera schachtii was present or absent. Aphid performance was influenced by these abiotic and biotic factors in an interactive way. Nematode presence decreased aphid performance when nitrate levels were low, whereas nematode infestation did not influence aphid performance under higher nitrate fertilization. Aphids followed the "mother knows best" principle when given a choice, settling preferentially on those plants on which they performed best. Hence, they preferred nematode-free over nematode-infested plants in the low fertilization treatment but host choice was not affected by nematodes under higher nitrate fertilization. The amino acid composition of the phloem exudates was significantly influenced by fertilization but also by the interaction of the two treatments. Various glucosinolates in the leaves, which provide an estimate of phloem glucosinolates, were not affected by the individual treatments but by the combination of fertilization and herbivory. These changes in primary and secondary metabolites may be decisive for the herbivore responses. Our data demonstrate that abiotic and biotic factors can interactively affect herbivores, adding a layer of complexity to plant-mediated herbivore interactions.

Bacteriophage vehicles for phage display: biology, mechanism, and application.

PubMed

Ebrahimizadeh, Walead; Rajabibazl, Masoumeh

2014-08-01

The phage display technique is a powerful tool for selection of various biological agents. This technique allows construction of large libraries from the antibody repertoire of different hosts and provides a fast and high-throughput selection method. Specific antibodies can be isolated based on distinctive characteristics from a library consisting of millions of members. These features made phage display technology preferred method for antibody selection and engineering. There are several phage display methods available and each has its unique merits and application. Selection of appropriate display technique requires basic knowledge of available methods and their mechanism. In this review, we describe different phage display techniques, available bacteriophage vehicles, and their mechanism.

[Helminth findings in indigenous raccoon dogs Nyctereutes procyonoides (Gray, 1843)].

PubMed

Thiess, A; Schuster, R; Nöckler, K; Mix, H

2001-01-01

Internal organs of 74 racoon dogs originating from the eastern districts of the Federal Land Brandenburg were subjected to a complete helminthological dissection. In addition, samples of diaphragma muscles from 46 further animals were examined for Trichinella larvae. Altogether 3 trematode- (Alaria alata, Isthmiophora melis, Metorchis bilis), 3 cestode- (Mesocestoides sp., Echinococcus multilocularis, Taenia polyacantha) and 7 nematode species (Capillaria aerophila, C. plica, Trichinella spiralis, Uncinaria stenocephala, Molineus patens, Crenosoma vulpis, Toxocara canis) could be identified. Thereby, the racoon dog has a comparable helminth spectrum as well known in red foxes. Differences in the frequency of the occurrence of helminths in both hosts can be explained by different food preferences.

Induction of Jasmonic Acid-Associated Defenses by Thrips Alters Host Suitability for Conspecifics and Correlates with Increased Trichome Densities in Tomato

PubMed Central

Klinkhamer, Peter G.L.; Leiss, Kirsten A.

2017-01-01

Plant defenses inducible by herbivorous arthropods can determine performance of subsequent feeding herbivores. We investigated how infestation of tomato (Solanum lycopersicum) plants with the Western flower thrips (Frankliniella occidentalis) alters host plant suitability and foraging decisions of their conspecifics. We explored the role of delayed-induced jasmonic acid (JA)-mediated plant defense responses in thrips preference by using the tomato mutant def-1, impaired in JA biosynthesis. In particular, we investigated the effect of thrips infestation on trichome-associated tomato defenses. The results showed that when offered a choice, thrips preferred non-infested plants over infested wild-type plants, while no differences were observed in def-1. Exogenous application of methyl jasmonate restored the repellency effect in def-1. Gene expression analysis showed induction of the JA defense signaling pathway in wild-type plants, while activating the ethylene signaling pathway in both genotypes. Activation of JA defenses led to increases in type-VI leaf glandular trichome densities in the wild type, augmenting the production of trichome-associated volatiles, i.e. terpenes. Our study revealed that plant-mediated intraspecific interactions between thrips are determined by JA-mediated defenses in tomato. We report that insects can alter not only trichome densities but also the allelochemicals produced therein, and that this response might depend on the magnitude and/or type of the induction. PMID:28158865

The Roles of Parasitoid Foraging for Hosts, Food and Mates in the Augmentative Control of Tephritidae

PubMed Central

Sivinski, John; Aluja, Martin

2012-01-01

Ultimately, the success of augmentative fruit fly biological control depends upon the survival, dispersal, attack rate and multi-generational persistence of mass-reared parasitoids in the field. Foraging for hosts, food and mates is fundamental to the above and, at an operational level, the choice of the parasitoid best suited to control a particular tephritid in a certain environment, release rate estimates and subsequent monitoring of effectiveness. In the following we review landscape-level and microhabitat foraging preferences, host/fruit ranges, orientation through environmental cues, host vulnerabilities/ovipositor structures, and inter and intraspecific competition. We also consider tephritid parasitoid mating systems and sexual signals, and suggest the directions of future research. PMID:26466622

Visual and Olfactory Floral Cues of Campanula (Campanulaceae) and Their Significance for Host Recognition by an Oligolectic Bee Pollinator

PubMed Central

Milet-Pinheiro, Paulo; Ayasse, Manfred; Dötterl, Stefan

2015-01-01

Oligolectic bees collect pollen from a few plants within a genus or family to rear their offspring, and are known to rely on visual and olfactory floral cues to recognize host plants. However, studies investigating whether oligolectic bees recognize distinct host plants by using shared floral cues are scarce. In the present study, we investigated in a comparative approach the visual and olfactory floral cues of six Campanula species, of which only Campanula lactiflora has never been reported as a pollen source of the oligolectic bee Ch. rapunculi. We hypothesized that the flowers of Campanula species visited by Ch. rapunculi share visual (i.e. color) and/or olfactory cues (scents) that give them a host-specific signature. To test this hypothesis, floral color and scent were studied by spectrophotometric and chemical analyses, respectively. Additionally, we performed bioassays within a flight cage to test the innate color preference of Ch. rapunculi. Our results show that Campanula flowers reflect the light predominantly in the UV-blue/blue bee-color space and that Ch. rapunculi displays a strong innate preference for these two colors. Furthermore, we recorded spiroacetals in the floral scent of all Campanula species, but Ca. lactiflora. Spiroacetals, rarely found as floral scent constituents but quite common among Campanula species, were recently shown to play a key function for host-flower recognition by Ch. rapunculi. We conclude that Campanula species share some visual and olfactory floral cues, and that neurological adaptations (i.e. vision and olfaction) of Ch. rapunculi innately drive their foraging flights toward host flowers. The significance of our findings for the evolution of pollen diet breadth in bees is discussed. PMID:26060994

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

PubMed

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

2017-05-01

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

Ecology of Meimuna mongolica (Hemiptera: Cicadidae) Nymphs: Instars, Morphological Variation, Vertical Distribution and Population Density, Host-Plant Selection, and Emergence Phenology

PubMed Central

Li, Qinglong; Yang, Mingsheng; Liu, Yunxiang; Wei, Cong

2015-01-01

The cicada Meimuna mongolica (Distant) (Hemiptera: Cicadidae) is one of the most important pests of economic forest in Guanzhong Plain of Shaanxi Province, China. Information about ecological characteristics and some sustainable control measures of this species is urgently required for its control. In this study, nymphal instars, morphological variation, vertical distribution, and population density in soil, and emergence phenology of nymphs of M. mongolica on three main host plants (Pinus tabuliformis Carr., Populus tomentosa Carr., and Pyrus xerophila Yü) were studied, based on combined morphological and molecular identification, investigation of the first-instar nymphs hatched from eggs and others excavated from soil, and investigation of exuviae in the adult emergence period. Five nymphal instars of M. mongolica were redetermined according to the distribution plots of the head capsule widths of the nymphs. Nymphs of third and fourth instars showed morphological variation, which is closely related to host-plant association. The mean densities of nymphs in soil under the three host plants were significantly different, indicating a distinct host preference. The nymphs could extend their distribution from the 0–10 cm soil layer to the 51–60 cm soil layer underground but not beyond 60 cm soil layer under all the three host plants. The 21–30 cm soil layer under all the three host plants has the highest nymphal population density. The sex ratio of the entire population was nearly 50:50, but males dominated in the early half of the duration of the emergence. These ecological characteristics of M. mongolica could provide important information for sustainable control measures.

Selective predation and productivity jointly drive complex behavior in host-parasite systems.

PubMed

Hall, Spencer R; Duffy, Meghan A; Cáceres, Carla E

2005-01-01

Successful invasion of a parasite into a host population and resulting host-parasite dynamics can depend crucially on other members of a host's community such as predators. We do not fully understand how predation intensity and selectivity shape host-parasite dynamics because the interplay between predator density, predator foraging behavior, and ecosystem productivity remains incompletely explored. By modifying a standard susceptible-infected model, we show how productivity can modulate complex behavior induced by saturating and selective foraging behavior of predators in an otherwise stable host-parasite system. When predators strongly prefer parasitized hosts, the host-parasite system can oscillate, but predators can also create alternative stable states, Allee effects, and catastrophic extinction of parasites. In the latter three cases, parasites have difficulty invading and/or persisting in ecosystems. When predators are intermediately selective, these more complex behaviors become less important, but the host-parasite system can switch from stable to oscillating and then back to stable states along a gradient of predator control. Surprisingly, at higher productivity, predators that neutrally select or avoid parasitized hosts can catalyze extinction of both hosts and parasites. Thus, synergy between two enemies can end disastrously for the host. Such diverse outcomes underscore the crucial importance of the community and ecosystem context in which host-parasite interactions occur.

The hemagglutinin structure of an avian H1N1 influenza A virus

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

Lin, Tianwei; Wang, Gengyan; Li, Anzhang

2009-09-15

The interaction between hemagglutinin (HA) and receptors is a kernel in the study of evolution and host adaptation of H1N1 influenza A viruses. The notion that the avian HA is associated with preferential specificity for receptors with Sia{alpha}2,3Gal glycosidic linkage over those with Sia{alpha}2,6Gal linkage is not all consistent with the available data on H1N1 viruses. By x-ray crystallography, the HA structure of an avian H1N1 influenza A virus, as well as its complexes with the receptor analogs, was determined. The structures revealed no preferential binding of avian receptor analogs over that of the human analog, suggesting that the HA/receptormore » binding might not be as stringent as is commonly believed in determining the host receptor preference for some subtypes of influenza viruses, such as the H1N1 viruses. The structure also showed difference in glycosylation despite the preservation of related sequences, which may partly contribute to the difference between structures of human and avian origin.« less

Host selection by the pine processionary moth enhances larval performance: An experiment

NASA Astrophysics Data System (ADS)

Pérez-Contreras, Tomás; Soler, Juan J.; Soler, Manuel

2014-02-01

The development of a phytophagous insect depends on the nutritional characteristics of plants on which it feeds. Offspring from different females, however, may vary in their ability to develop in different host species and therefore females should place their eggs on host plants that result in the highest performance for the insect offspring. Causes underlying the predicted relationships between host selection and offspring performance may be: (1) a genetic association between larval ability to exploit particular hosts and the female insect's host preference; and (2) phenotypic plasticity of larvae that may be due to (a) maternal effects (e.g. differential investment in eggs) or (b) diet. In this work, we analyse the performance (i.e. hatching success and larval size and mortality) of the pine processionary (Thaumetopoea pityocampa) caterpillar developing in Aleppo (Pinus halepensis) or maritime (Pinus pinaster) pines. Larvae of this moth species do not move from the individual pine selected by the mother for oviposition. By means of cross-fostering experiments of eggs batches and silk nests of larvae between these two pine species, we explored whether phenotypic plasticity of offspring traits or genetic correlations between mother and offspring traits account for variation in developmental characteristics of caterpillars. Our results showed that females preferentially selected Aleppo pine for oviposition. Moreover, the offspring had the highest probability of survival and reached a larger body size in this pine species independently of whether or not batches were experimentally cross-fostered. Notably, the interaction between identity of donor and receiver pine species of larvae nests explained a significant proportion of variance of larval size and mortality, suggesting a role of diet-induced phenotypic plasticity of the hatchlings. These results suggest that both female selection of the more appropriate pine species and phenotypic plasticity of larva explain the performance of pine processionary caterpillars.

The Role of Culex pipiens L. (Diptera: Culicidae) in Virus Transmission in Europe

PubMed Central

Hernández-Triana, Luis M.; Medlock, Jolyon M.; Fooks, Anthony R.; Carpenter, Simon; Johnson, Nicholas

2018-01-01

Over the past three decades, a range of mosquito-borne viruses that threaten public and veterinary health have emerged or re-emerged in Europe. Mosquito surveillance activities have highlighted the Culex pipiens species complex as being critical for the maintenance of a number of these viruses. This species complex contains morphologically similar forms that exhibit variation in phenotypes that can influence the probability of virus transmission. Critical amongst these is the choice of host on which to feed, with different forms showing different feeding preferences. This influences the ability of the mosquito to vector viruses and facilitate transmission of viruses to humans and domestic animals. Biases towards blood-feeding on avian or mammalian hosts have been demonstrated for different Cx. pipiens ecoforms and emerging evidence of hybrid populations across Europe adds another level of complexity to virus transmission. A range of molecular methods based on DNA have been developed to enable discrimination between morphologically indistinguishable forms, although this remains an active area of research. This review provides a comprehensive overview of developments in the understanding of the ecology, behaviour and genetics of Cx. pipiens in Europe, and how this influences arbovirus transmission. PMID:29473903

Ape malaria transmission and potential for ape-to-human transfers in Africa

PubMed Central

Makanga, Boris; Yangari, Patrick; Rahola, Nil; Rougeron, Virginie; Elguero, Eric; Boundenga, Larson; Moukodoum, Nancy Diamella; Okouga, Alain Prince; Arnathau, Céline; Durand, Patrick; Willaume, Eric; Ayala, Diego; Fontenille, Didier; Ayala, Francisco J.; Renaud, François; Ollomo, Benjamin; Prugnolle, Franck; Paupy, Christophe

2016-01-01

Recent studies have highlighted the large diversity of malaria parasites infecting African great apes (subgenus Laverania) and their strong host specificity. Although the existence of genetic incompatibilities preventing the cross-species transfer may explain host specificity, the existence of vectors with a high preference for a determined host represents another possibility. To test this hypothesis, we undertook a 15-mo-long longitudinal entomological survey in two forest regions of Gabon, where wild apes live, at different heights under the canopy. More than 2,400 anopheline mosquitoes belonging to 18 species were collected. Among them, only three species of Anopheles were found infected with ape Plasmodium: Anopheles vinckei, Anopheles moucheti, and Anopheles marshallii. Their role in transmission was confirmed by the detection of the parasites in their salivary glands. Among these species, An. vinckei showed significantly the highest prevalence of infection and was shown to be able to transmit parasites of both chimpanzees and gorillas. Transmission was also shown to be conditioned by seasonal factors and by the heights of capture under the canopy. Moreover, human landing catches of sylvan Anopheles demonstrated the propensity of these three vector species to feed on humans when available. Our results suggest therefore that the strong host specificity observed in the Laveranias is not linked to a specific association between the vertebrate host and the vector species and highlight the potential role of these vectors as bridge between apes and humans. PMID:27071123

Selective logging in tropical forests decreases the robustness of liana-tree interaction networks to the loss of host tree species.

PubMed

Magrach, Ainhoa; Senior, Rebecca A; Rogers, Andrew; Nurdin, Deddy; Benedick, Suzan; Laurance, William F; Santamaria, Luis; Edwards, David P

2016-03-16

Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in species composition. Whether such changes modify interactions between species and the networks in which they are embedded remain fundamental questions to assess the 'health' and ecosystem functionality of logged forests. We focus on interactions between lianas and their tree hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher species richness, and different species compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing tree species, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host tree local species loss indicated that logging might decrease the robustness of liana-tree interaction networks if heavily infested trees (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host trees by a greater diversity of liana species within logged forests, yet this might not compensate for the loss of preferred tree hosts in the long term. As a consequence, species interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in species richness and ecosystem function in response to additional disturbances, representing a new type of 'extinction debt'. © 2016 The Author(s).

Selective logging in tropical forests decreases the robustness of liana–tree interaction networks to the loss of host tree species

PubMed Central

Magrach, Ainhoa; Senior, Rebecca A.; Rogers, Andrew; Nurdin, Deddy; Benedick, Suzan; Laurance, William F.; Santamaria, Luis; Edwards, David P.

2016-01-01

Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in species composition. Whether such changes modify interactions between species and the networks in which they are embedded remain fundamental questions to assess the ‘health’ and ecosystem functionality of logged forests. We focus on interactions between lianas and their tree hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher species richness, and different species compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing tree species, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host tree local species loss indicated that logging might decrease the robustness of liana–tree interaction networks if heavily infested trees (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host trees by a greater diversity of liana species within logged forests, yet this might not compensate for the loss of preferred tree hosts in the long term. As a consequence, species interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in species richness and ecosystem function in response to additional disturbances, representing a new type of ‘extinction debt’. PMID:26936241

Constructing Cost-Effective and Targetable ICS Honeypots Suited for Production Networks

DTIC Science & Technology

2015-03-26

introducing Honeyd+ has a marginal impact on performance. Notable findings are that the Raspberry Pi is the preferred hosting platform for the EtherNet/IP... Raspberry Pi or Gumstix, which is a low-cost approach to replicating multiple decoys. One hidden drawback to low- interaction honeypots is the extensive time...EtherNet/IP industrial protocol. Honeyd+ is hosted on a low-cost computing platform ( Raspberry Pi running Raspbian, approximately $50) and a high-cost

Can reduced predation offset negative effects of sea louse parasites on chum salmon?

PubMed Central

Peacock, Stephanie J.; Connors, Brendan M.; Krkošek, Martin; Irvine, James R.; Lewis, Mark A.

2014-01-01

The impact of parasites on hosts is invariably negative when considered in isolation, but may be complex and unexpected in nature. For example, if parasites make hosts less desirable to predators then gains from reduced predation may offset direct costs of being parasitized. We explore these ideas in the context of sea louse infestations on salmon. In Pacific Canada, sea lice can spread from farmed salmon to migrating juvenile wild salmon. Low numbers of sea lice can cause mortality of juvenile pink and chum salmon. For pink salmon, this has resulted in reduced productivity of river populations exposed to salmon farming. However, for chum salmon, we did not find an effect of sea louse infestations on productivity, despite high statistical power. Motivated by this unexpected result, we used a mathematical model to show how a parasite-induced shift in predation pressure from chum salmon to pink salmon could offset negative direct impacts of sea lice on chum salmon. This shift in predation is proposed to occur because predators show an innate preference for pink salmon prey. This preference may be more easily expressed when sea lice compromise juvenile salmon hosts, making them easier to catch. Our results indicate how the ecological context of host–parasite interactions may dampen, or even reverse, the expected impact of parasites on host populations. PMID:24352951

Revelation of Influencing Factors in Overall Codon Usage Bias of Equine Influenza Viruses

PubMed Central

Bhatia, Sandeep; Sood, Richa; Selvaraj, Pavulraj

2016-01-01

Equine influenza viruses (EIVs) of H3N8 subtype are culprits of severe acute respiratory infections in horses, and are still responsible for significant outbreaks worldwide. Adaptability of influenza viruses to a particular host is significantly influenced by their codon usage preference, due to an absolute dependence on the host cellular machinery for their replication. In the present study, we analyzed genome-wide codon usage patterns in 92 EIV strains, including both H3N8 and H7N7 subtypes by computing several codon usage indices and applying multivariate statistical methods. Relative synonymous codon usage (RSCU) analysis disclosed bias of preferred synonymous codons towards A/U-ended codons. The overall codon usage bias in EIVs was slightly lower, and mainly affected by the nucleotide compositional constraints as inferred from the RSCU and effective number of codon (ENc) analysis. Our data suggested that codon usage pattern in EIVs is governed by the interplay of mutation pressure, natural selection from its hosts and undefined factors. The H7N7 subtype was found less fit to its host (horse) in comparison to H3N8, by possessing higher codon bias, lower mutation pressure and much less adaptation to tRNA pool of equine cells. To the best of our knowledge, this is the first report describing the codon usage analysis of the complete genomes of EIVs. The outcome of our study is likely to enhance our understanding of factors involved in viral adaptation, evolution, and fitness towards their hosts. PMID:27119730

Leaf Colour as a Signal of Chemical Defence to Insect Herbivores in Wild Cabbage (Brassica oleracea).

PubMed

Green, Jonathan P; Foster, Rosie; Wilkins, Lucas; Osorio, Daniel; Hartley, Susan E

2015-01-01

Leaf colour has been proposed to signal levels of host defence to insect herbivores, but we lack data on herbivory, leaf colour and levels of defence for wild host populations necessary to test this hypothesis. Such a test requires measurements of leaf spectra as they would be sensed by herbivore visual systems, as well as simultaneous measurements of chemical defences and herbivore responses to leaf colour in natural host-herbivore populations. In a large-scale field survey of wild cabbage (Brassica oleracea) populations, we show that variation in leaf colour and brightness, measured according to herbivore spectral sensitivities, predicts both levels of chemical defences (glucosinolates) and abundance of specialist lepidopteran (Pieris rapae) and hemipteran (Brevicoryne brassicae) herbivores. In subsequent experiments, P. rapae larvae achieved faster growth and greater pupal mass when feeding on plants with bluer leaves, which contained lower levels of aliphatic glucosinolates. Glucosinolate-mediated effects on larval performance may thus contribute to the association between P. rapae herbivory and leaf colour observed in the field. However, preference tests found no evidence that adult butterflies selected host plants based on leaf coloration. In the field, B. brassicae abundance varied with leaf brightness but greenhouse experiments were unable to identify any effects of brightness on aphid preference or performance. Our findings suggest that although leaf colour reflects both levels of host defences and herbivore abundance in the field, the ability of herbivores to respond to colour signals may be limited, even in species where performance is correlated with leaf colour.

Leaf Colour as a Signal of Chemical Defence to Insect Herbivores in Wild Cabbage (Brassica oleracea)

PubMed Central

Wilkins, Lucas; Osorio, Daniel; Hartley, Susan E.

2015-01-01

Leaf colour has been proposed to signal levels of host defence to insect herbivores, but we lack data on herbivory, leaf colour and levels of defence for wild host populations necessary to test this hypothesis. Such a test requires measurements of leaf spectra as they would be sensed by herbivore visual systems, as well as simultaneous measurements of chemical defences and herbivore responses to leaf colour in natural host-herbivore populations. In a large-scale field survey of wild cabbage (Brassica oleracea) populations, we show that variation in leaf colour and brightness, measured according to herbivore spectral sensitivities, predicts both levels of chemical defences (glucosinolates) and abundance of specialist lepidopteran (Pieris rapae) and hemipteran (Brevicoryne brassicae) herbivores. In subsequent experiments, P. rapae larvae achieved faster growth and greater pupal mass when feeding on plants with bluer leaves, which contained lower levels of aliphatic glucosinolates. Glucosinolate-mediated effects on larval performance may thus contribute to the association between P. rapae herbivory and leaf colour observed in the field. However, preference tests found no evidence that adult butterflies selected host plants based on leaf coloration. In the field, B. brassicae abundance varied with leaf brightness but greenhouse experiments were unable to identify any effects of brightness on aphid preference or performance. Our findings suggest that although leaf colour reflects both levels of host defences and herbivore abundance in the field, the ability of herbivores to respond to colour signals may be limited, even in species where performance is correlated with leaf colour. PMID:26353086

Herbivore pressure by weevils associated with flower color polymorphism in Geranium thunbergii (Geraniaceae).

PubMed

Tsuchimatsu, Takashi; Yoshitake, Hiraku; Ito, Motomi

2014-03-01

Although floral herbivory has recently received increased attention as an important factor influencing plant reproduction, relatively little is known about how its frequency and intensity vary depending on traits of host plants. Here we report that herbivore pressure by a weevil, Zacladus geranii, is associated with a flower color polymorphism of Geranium thunbergii (Geraniaceae). Pink and white flower color morphs have been reported in G. thunbergii, and we found in a three-year field survey in multiple populations that, generally, adult weevils more preferentially visited white flowers than pink flowers. Consistently, we found more severe damage by weevil larvae in white flowers. Overall herbivore pressure for G. thunbergii varied strongly between populations, and the difference seems to be partly explained by the co-occurrence of a related plant species, Geranium yezoense, in a population, as weevils preferred it to both color morphs of G. thunbergii, thereby relaxing overall herbivore pressure for G. thunbergii. Nonetheless, despite such high variability, the preference of weevils for white morphs over pink morphs of G. thunbergii was found across multiple populations. We discuss possible mechanisms causing the association between flower color and herbivore preference as well as its evolutionary consequences.

Protecting cows in small holder farms in East Africa from tsetse flies by mimicking the odor profile of a non-host bovid

PubMed Central

Orindi, Benedict O.; Mbahin, Norber; Muasa, Peter N.; Mbuvi, David M.; Muya, Caroline M.; Pickett, John A.; Borgemeister, Christian W.

2017-01-01

Background For the first time, differential attraction of pathogen vectors to vertebrate animals is investigated for novel repellents which when applied to preferred host animals turn them into non-hosts thereby providing a new paradigm for innovative vector control. For effectively controlling tsetse flies (Glossina spp.), vectors of African trypanosomosis, causing nagana, repellents more powerful than plant derived, from a non-host animal the waterbuck, Kobus ellipsiprymnus defassa, have recently been identified. Here we investigate these repellents in the field to protect cattle from nagana by making cattle as unattractive as the buck. Methodology/Principal findings To dispense the waterbuck repellents comprising guaiacol, geranylacetone, pentanoic acid and δ-octalactone, (patent application) we developed an innovative collar-mounted release system for individual cattle. We tested protecting cattle, under natural tsetse challenge, from tsetse transmitted nagana in a large field trial comprising 1,100 cattle with repellent collars in Kenya for 24 months. The collars provided substantial protection to livestock from trypanosome infection by reducing disease levels >80%. Protected cattle were healthier, showed significantly reduced disease levels, higher packed cell volume and significantly increased weight. Collars >60% reduced trypanocide use, 72.7% increase in ownership of oxen per household and enhanced traction power (protected animals ploughed 66% more land than unprotected). Land under cultivation increased by 73.4%. Increase in traction power of protected animals reduced by 69.1% acres tilled by hand per household per ploughing season. Improved food security and household income from very high acceptance of collars (99%) motivated the farmers to form a registered community based organization promoting collars for integrated tsetse control and their commercialization. Conclusion/Significance Clear demonstration that repellents from un-preferred hosts prevent contact between host and vector, thereby preventing disease transmission: a new paradigm for vector control. Evidence that deploying water buck repellents converts cattle into non-hosts for tsetse flies—‘cows in waterbuck clothing’. PMID:29040267

48 CFR 636.104-70 - Foreign Service Buildings Act of 1926, as amended.

Code of Federal Regulations, 2011 CFR

2011-10-01

... or limited to: (1) Host-country firms where required by international agreement; or (2) By the laws... preference. For purposes of determining competitive status, American-owned firms shall receive a ten (10...

Host selection and gonotrophic cycle length of Anopheles punctimacula in southern Mexico.

PubMed

Ulloa, Armando; Gonzalez-Cerón, Lilia; Rodríguez, Mario H

2006-12-01

The host preference, survival rates, and length of the gonotrophic cycle of Anopheles punctimacula was investigated in southern México. Mosquitoes were collected in 15-day separate experiments during the rainy and dry seasons. Daily changes in the parous-nulliparous ratio were recorded and the gonotrophic cycle length was estimated by a time series analysis. Anopheles punctimacula was most abundant during the dry season and preferred animals to humans. The daily survival rate in mosquitoes collected in animal traps was 0.96 (parity rate = 0.86; gonotrophic cycle = 4 days). The length of gonotrophic cycle of 4 days was estimated on the base of a high correlation coefficient value appearing every 4 days. The minimum time estimated for developing mature eggs after blood feeding was 72 h. The proportion of mosquitoes living enough to transmit Plasmodium vivax malaria during the dry season was 0.35.

A non-persistently transmitted-virus induces a pull-push strategy in its aphid vector to optimize transmission and spread.

PubMed

Carmo-Sousa, Michele; Moreno, Aranzazu; Garzo, Elisa; Fereres, Alberto

2014-06-24

Plant viruses are known to modify the behaviour of their insect vectors, both directly and indirectly, generally adapting to each type of virus-vector relationship in a way that enhances transmission efficiency. Here, we report results of three different studies showing how a virus transmitted in a non-persistent (NP) manner (Cucumber mosaic virus; CMV, Cucumovirus) can induce changes in its host plant, cucumber (Cucumis sativus cv. Marumba) that modifies the behaviour of its aphid vector (Aphis gossypii Glover; Hemiptera: Aphididae) in a way that enhances virus transmission and spread non-viruliferous aphids changed their alighting, settling and probing behaviour activities over time when exposed to CMV-infected and mock-inoculated cucumber plants. Aphids exhibited no preference to migrate from CMV-infected to mock-inoculated plants at short time intervals (1, 10 and 30 min after release), but showed a clear shift in preference to migrate from CMV-infected to mock-inoculated plants 60 min after release. Our free-choice preference assays showed that A. gossypii alates preferred CMV-infected over mock-inoculated plants at an early stage (30 min), but this behaviour was reverted at a later stage and aphids preferred to settle and reproduce on mock-inoculated plants. The electrical penetration graph (EPG) technique revealed a sharp change in aphid probing behaviour over time when exposed to CMV-infected plants. At the beginning (first 15 min) aphid vectors dramatically increased the number of short superficial probes and intracellular punctures when exposed to CMV-infected plants. At a later stage (second hour of recording) aphids diminished their feeding on CMV-infected plants as indicated by much less time spent in phloem salivation and ingestion (E1 and E2). This particular probing behaviour including an early increase in the number of short superficial probes and intracellular punctures followed by a phloem feeding deterrence is known to enhance the transmission efficiency of viruses transmitted in a NP manner. We conclude that CMV induces specific changes in a plant host that modify the alighting, settling and probing behaviour of its main vector A. gossypii, leading to optimum transmission and spread of the virus. Our findings should be considered when modelling the spread of viruses transmitted in a NP manner. Copyright © 2013 Elsevier B.V. All rights reserved.

Variation in the strength of male mate choice allows long-term coexistence of sperm-dependent asexuals and their sexual hosts.

PubMed

Mee, Jonathan A; Otto, Sarah P

2010-10-01

In several asexual taxa, reproduction requires mating with related sexual species to stimulate egg development, even though genetic material is not incorporated from the sexuals (gynogenesis). In cases in which gynogens do not invest in male function, they can potentially have a twofold competitive advantage over sexuals because the asexuals avoid the cost of producing males. If unmitigated, however, the competitive success of the asexuals would ultimately lead to their own demise, following the extinction of the sexual species that stimulate egg development. We have studied a model of mate choice among sexual individuals and asexual gynogens, where males of the sexual species preferentially mate with sexual females over gynogenetic females, to determine if such mating preferences can stably maintain both gynogenetic and sexual individuals within a community. Our model shows that stable coexistence of gynogens and their sexual hosts can occur when there is variation among males in the degree of preference for mating with sexual females and when pickier males pay a higher cost of preference. © 2010 The Author(s). Journal compilation © 2010 The Society for the Study of Evolution.

Field Biology of the Beetle Aegopsis bolboceridus in Brazil, with a List of Host Plants

PubMed Central

Oliveira, Charles M.; Frizzas, Marina R.

2013-01-01

The white grub, Aegopsis bolboceridus (Thomson) (Coleoptera: Melolonthidae), is an important vegetable and corn pest in central Brazil. The objective of this study was to examine the biology of A. bolboceridus in the field and to update the list of its host plants. The study was conducted in an area with vegetable crops and corn located in the Federal District of Brazil. Samplings were taken to observe the biological stages of A. bolboceridus, preferred oviposition sites, and the adult swarming period. A. bolboceridus exhibited a univoltine cycle that lasted approximately 12 months from egg to active adults. Its eggs were found from October to November. The larval stage lasted approximately eight months, occurring between October and May. Pre-pupae were observed between April and June, and pupae were found between May and July. Inactive adults were observed in July and August, and the swarming period was between September and October. The females preferred to oviposit in sites with taller plants. Four new plant species were identified as hosts for this pest, and two new locations were recorded for its occurrence. This study is the first to describe the biology of a representative of the tribe Agaocephalini in Brazil. PMID:23909396

Carambola Cultivar, Fruit Ripeness, and Damage by Conspecific Larvae Influence the Host-Related Behaviors of Anastrepha obliqua (Diptera: Tephritidae).

PubMed

López-Ley, Jorge Ulises; Toledo, Jorge; Malo, Edi A; Gomez, Jaime; Santiesteban, Antonio; Rojas, Julio C

2016-02-01

In this study, we investigated the influence of cultivar type, fruit ripeness, and damage by conspecific larvae on the attraction of Anastrepha obliqua (Macquart) (Diptera: Tephritidae) to and oviposition on carambola fruit (Averroha carambola L.). The attraction of both sexes of A. obliqua to fruit of different quality was evaluated through cage experiments in the field, and the oviposition preferences of mated females were examined in laboratory tests. Both sexes, mated or virgin, were more attracted to the "Maha" fruit than to the "Golden Star" fruit, and the females oviposited more frequently on the Maha cultivar than the Golden Star cultivar. Both sexes were more attracted to ripe and half-ripe Maha fruits than to mature green fruit, and although females did not show a preference for ovipositing on half-ripe or ripe fruits, they did not oviposit on mature green fruits. Males did not show a preference for the volatiles from uninfested, artificially damaged, or infested Maha fruits, but females were more attracted to uninfested fruits than to artificially damaged and infested Maha fruits. Furthermore, females preferred to oviposit on uninfested fruits compared with artificially damaged fruit, and they did not oviposit on infested fruits. © 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.

[Ecological observations on Biomphalaria straminea (Dunker, 1848) in areas of the northeast, Brazil].

PubMed

Rosas, E

1987-01-01

The different climatic regions determine the zoogeographic distribution of various animal species depending on their particular conditions and ecological preferences. The host schistosomiasis planorbid is one of these species. This paper deals with the distribution of Biomphalaria straminea in northeast Brazil. It starts from the analysis of different climatic peculiarities in this region, associated to limnological observation done by the author in three different hydric collections in the state of Sergipe. It has been concluded that this is an "eurióioca" species. Its broad ecological valence permits this species to survive in regions where climate asperties are evident, requiring behavior and physiological adaptations. The species survives in all northeast region, from "zona da mata", in the coast, to the semi-arid "sertão".

Evaluation of roadside greenbelt trees damage caused by strangler plants in Bogor

NASA Astrophysics Data System (ADS)

Danniswari, Dibyanti; Nasrullah, Nizar

2017-10-01

Certain plants are called stranglers (hemiepiphyte) because they grow on host trees and slowly choking the host, which often results in the host’s death. The existence of strangler plants on roadside greenbelt trees is quite common in Bogor, but they may cause tree’s failure and threaten users’ safety. To prevent such hazard, evaluation of roadside greenbelt trees damage caused by strangler plants is important. This study was directed to analyse the vegetation of strangler plants in Bogor, to assess the damage caused by stranglers, and to compose strangled trees maintenance recommendations. This study was conducted in March to May 2014 by doing survey at five major roads in Bogor, which were Jalan Ahmad Yani, Jalan Sudirman, Jalan Pemuda, Jalan Semeru, and Jalan Juanda. The results showed that strangler species found in Bogor are Ficus benjamina, Ficus glauca, Ficus elastica, and Schefflera actinophylla. The most common species in Bogor is F. benjamina. Host trees that tend to be preferred by strangler plants are trees with large trunk, many branches, and medium to high height. The maintenance for every strangled tree is different according to the damage level, mild to severe damage could be treated by strangler root cutting to tree logging, respectively.

A Herbivore Tag-and-Trace System Reveals Contact- and Density-Dependent Repellence of a Root Toxin.

PubMed

Bont, Zoe; Arce, Carla; Huber, Meret; Huang, Wei; Mestrot, Adrien; Sturrock, Craig J; Erb, Matthias

2017-03-01

Foraging behavior of root feeding organisms strongly affects plant-environment-interactions and ecosystem processes. However, the impact of plant chemistry on root herbivore movement in the soil is poorly understood. Here, we apply a simple technique to trace the movement of soil-dwelling insects in their habitats without disturbing or restricting their interactions with host plants. We tagged the root feeding larvae of Melolontha melolontha with a copper ring and repeatedly located their position in relation to their preferred host plant, Taraxacum officinale, using a commercial metal detector. This method was validated and used to study the influence of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) on the foraging of M. melolontha. TA-G is stored in the latex of T. officinale and protects the roots from herbivory. Using behavioral arenas with TA-G deficient and control plants, we tested the impact of physical root access and plant distance on the effect of TA-G on M. melolontha. The larvae preferred TA-G deficient plants to control plants, but only when physical root contact was possible and the plants were separated by 5 cm. Melolontha melolontha showed no preference for TA-G deficient plants when the plants were grown 15 cm apart, which may indicate a trade-off between the cost of movement and the benefit of consuming less toxic food. We demonstrate that M. melolontha integrates host plant quality and distance into its foraging patterns and suggest that plant chemistry affects root herbivore behavior in a plant-density dependent manner.

Amoeba host-Legionella synchronization of amino acid auxotrophy and its role in bacterial adaptation and pathogenic evolution

PubMed Central

Price, Christopher T. D.; Richards, Ashley M.; Von Dwingelo, Juanita E.; Samara, Hala A.; Kwaik, Yousef Abu

2013-01-01

Summary Legionella pneumophila, the causative agent of Legionnaires’ disease, invades and proliferates within a diverse range of free-living amoeba in the environment but upon transmission to humans the bacteria hijack alveolar macrophages. Intracellular proliferation of L. pneumophila in two evolutionarily distant hosts is facilitated by bacterial exploitation of conserved host processes that are targeted by bacterial protein effectors injected into the host cell. A key aspect of microbe-host interaction is microbial extraction of nutrients from the host but understanding of this is still limited. AnkB functions as a nutritional virulence factor and promotes host proteasomal degradation of polyubiquitinated proteins generating gratuitous levels of limiting host cellular amino acids. L. pneumophila is auxotrophic for several amino acids including cysteine, which is a metabolically preferred source of carbon and energy during intracellular proliferation, but is limiting in both amoebae and humans. We propose that synchronization of bacterial amino acids auxotrophy with the host is a driving force in pathogenic evolution and nutritional adaptation of L. pneumophila and other intracellular bacteria to life within the host cell. Understanding microbial strategies of nutrient generation and acquisition in the host will provide novel antimicrobial strategies to disrupt pathogen access to essential sources of carbon and energy. PMID:24112119

Evolution in action: climate change, biodiversity dynamics and emerging infectious disease.

PubMed

Hoberg, Eric P; Brooks, Daniel R

2015-04-05

Climatological variation and ecological perturbation have been pervasive drivers of faunal assembly, structure and diversification for parasites and pathogens through recurrent events of geographical and host colonization at varying spatial and temporal scales of Earth history. Episodic shifts in climate and environmental settings, in conjunction with ecological mechanisms and host switching, are often critical determinants of parasite diversification, a view counter to more than a century of coevolutionary thinking about the nature of complex host-parasite assemblages. Parasites are resource specialists with restricted host ranges, yet shifts onto relatively unrelated hosts are common during phylogenetic diversification of parasite lineages and directly observable in real time. The emerging Stockholm Paradigm resolves this paradox: Ecological Fitting (EF)--phenotypic flexibility and phylogenetic conservatism in traits related to resource use, most notably host preference--provides many opportunities for rapid host switching in changing environments, without the evolution of novel host-utilization capabilities. Host shifts via EF fuel the expansion phase of the Oscillation Hypothesis of host range and speciation and, more generally, the generation of novel combinations of interacting species within the Geographic Mosaic Theory of Coevolution. In synergy, an environmental dynamic of Taxon Pulses establishes an episodic context for host and geographical colonization. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Structural investigation of the β-cyclodextrin complexes with chiral bicyclic monoterpenes - Influence of the functionality group on the host-guest stoichiometry

NASA Astrophysics Data System (ADS)

Ceborska, Magdalena

2017-10-01

The crystal structures of the complexes of β-cyclodextrin with (+)- and (-)-camphors are presented. The comparison of the obtained crystal structures with available data for other complexes of β-cyclodextrin with chiral bicyclic monoterpenes (hydrocarbon (+)-fenchene and alcohols: (-)-isopinocampheol, and (+)-, and (-)-borneols) obtained from Cambridge Structural Database (CSD) shows the trend of alcohols to form dimeric complexes of 2:3 stoichiometry, while hydrocarbons and ketones prefer to form 2:2 host-guest inclusion complexes.

Infestivity of Demodex canis to hamster skin engrafted onto SCID mice.

PubMed

Tani, Kenji; Une, Satoshi; Hasegawa, Atsuhiko; Adachi, Makoto; Kanda, Naoko; Watanabe, Shin-ichi; Nakaichi, Munekazu; Taura, Yasuho

2005-04-01

We demonstrated that Demodex canis was transferred to skin xenografts of a dog and a hamster onto severe combined immunodeficiency mice. After the transfer of mites, the number of eggs, larvae, nymphs and adult mites per gram of canine and hamster xenografts increased, whereas no live mites were detected on murine allograft. These results indicate that D. canis proliferates in hair follicles of dog and hamster skins but not in murine allograft. Therefore, D. canis may have host preference but not strict host-specificity.

Correlations between Colonization of Onion Thrips and Leaf Reflectance Measures across Six Cabbage Varieties

PubMed Central

Bálint, János; Nagy, Balázs Vince; Fail, József

2013-01-01

The main purpose of this study was to reveal if the UV-A, and visible light reflection of leaves of white cabbage varieties is correlated to resistance against onion thrips. The antixenotic resistance (AR) against onion thrips and thrips damage differed between varieties Balashi, Bloktor, Riana – considered resistant – and Green Gem, Hurricane, Quisor – considered susceptible. The solar UV-A (340–400 nm) and visible (401–650 nm) light reflection of white cabbage leaves were recorded. Correlation between AR against onion thrips and reflection of leaves in UV-A and visible range of the studied white cabbage varieties were computed. According to the AR evaluation onion thrips density was always higher on susceptible than on resistant varieties. The UV-A light reflection of head forming leaves and the contrast between head and exterior leaves (H/E) was negatively correlated with onion thrips host preference at an early stage of cabbage head formation. The visible light reflection of both head forming and exterior leaves was also negatively correlated with onion thrips host preference. Susceptible varieties had greater damage ratings at harvest than resistant ones and positive correlations were observed between AR and damage. AR against onion thrips may be affected by differences in reflection of cabbage leaves at an early growth stage. It is suggested that more intensive reflection of leaves and/or higher contrast values between the reflectance intensity of head versus outer leaves made the resistant varieties less attractive to onion thrips. Our results reported here provide the first evidence of negative correlation between UV-A and visible reflection of leaves and AR of white cabbage against a dangerous insect pest, opening new perspectives for understanding the role of reflection by plant leaves in pest management. PMID:24040093

SARS hCoV papain-like protease is a unique Lys48 linkage-specific di-distributive deubiquitinating enzyme

PubMed Central

Békés, Miklós; Rut, Wioletta; Kasperkiewicz, Paulina; Mulder, Monique P. C.; Ovaa, Huib; Drag, Marcin; Lima, Christopher D.; Huang, Tony T.

2015-01-01

Ubiquitin (Ub) and the ubiquitin-like modifier interferon stimulated gene 15 (ISG15) participate in the host defense of viral infections. Viruses, including the Severe Acute Respiratory Syndrome human coronavirus (SARS hCoV), have co-opted Ub/ISG15-conjugation pathways for their own advantage or have evolved effector proteins to counter pro-inflammatory properties of Ub/ISG15-conjugated host proteins. Here, we compare substrate specificities of the papain-like protease (PLpro) from the recently emerged Middle Eastern Respiratory Syndrome (MERS) hCoV to the related protease from SARS, SARS PLpro. Through biochemical assays, we show that similar to SARS PLpro, MERS PLpro is both a deubiquitinating and a deISGylating enzyme. Further analysis of the intrinsic deubiquitinating enzyme (DUB) activity of these viral proteases revealed unique differences between the recognition and cleavage specificities of polyUb chains. First, MERS PLpro shows broad linkage specificity for the cleavage of polyUb chains, while SARS PLpro prefers to cleave Lys48-linked polyUb chains. Second, MERS PLpro cleaves polyUb chains in a “mono-distributive” manner (one Ub at a time), and SARS PLpro prefers to cleave K48-linked poly-Ub chains by sensing a di-Ub moiety as a minimal recognition element using a “di-distributive” cleavage mechanism. The di-distributive cleavage mechanism for SARS PLpro appears to be uncommon among USP-family DUBs, as related USP family members from humans do not display such a mechanism. We propose that these intrinsic enzymatic differences between SARS and MERS PLpro will help identify pro-inflammatory substrates of these viral DUBs and can guide in the design of therapeutics to combat infection by coronaviruses. PMID:25764917

SARS hCoV papain-like protease is a unique Lys48 linkage-specific di-distributive deubiquitinating enzyme.

PubMed

Békés, Miklós; Rut, Wioletta; Kasperkiewicz, Paulina; Mulder, Monique P C; Ovaa, Huib; Drag, Marcin; Lima, Christopher D; Huang, Tony T

2015-06-01

Ubiquitin (Ub) and the Ub-like (Ubl) modifier interferon-stimulated gene 15 (ISG15) participate in the host defence of viral infections. Viruses, including the severe acute respiratory syndrome human coronavirus (SARS hCoV), have co-opted Ub-ISG15 conjugation pathways for their own advantage or have evolved effector proteins to counter pro-inflammatory properties of Ub-ISG15-conjugated host proteins. In the present study, we compare substrate specificities of the papain-like protease (PLpro) from the recently emerged Middle East respiratory syndrome (MERS) hCoV to the related protease from SARS, SARS PLpro. Through biochemical assays, we show that, similar to SARS PLpro, MERS PLpro is both a deubiquitinating (DUB) and a deISGylating enzyme. Further analysis of the intrinsic DUB activity of these viral proteases revealed unique differences between the recognition and cleavage specificities of polyUb chains. First, MERS PLpro shows broad linkage specificity for the cleavage of polyUb chains, whereas SARS PLpro prefers to cleave Lys48-linked polyUb chains. Secondly, MERS PLpro cleaves polyUb chains in a 'mono-distributive' manner (one Ub at a time) and SARS PLpro prefers to cleave Lys48-linked polyUb chains by sensing a di-Ub moiety as a minimal recognition element using a 'di-distributive' cleavage mechanism. The di-distributive cleavage mechanism for SARS PLpro appears to be uncommon among USP (Ub-specific protease)-family DUBs, as related USP family members from humans do not display such a mechanism. We propose that these intrinsic enzymatic differences between SARS and MERS PLpro will help to identify pro-inflammatory substrates of these viral DUBs and can guide in the design of therapeutics to combat infection by coronaviruses.

Jasmonic acid-induced volatiles of Brassica oleracea attract parasitoids: effects of time and dose, and comparison with induction by herbivores

PubMed Central

Bruinsma, Maaike; Posthumus, Maarten A.; Mumm, Roland; Mueller, Martin J.; van Loon, Joop J. A.; Dicke, Marcel

2009-01-01

Caterpillar feeding induces direct and indirect defences in brassicaceous plants. This study focused on the role of the octadecanoid pathway in induced indirect defence in Brassica oleracea. The effect of induction by exogenous application of jasmonic acid (JA) on the responses of Brussels sprouts plants and on host-location behaviour of associated parasitoid wasps was studied. Feeding by the biting–chewing herbivores Pieris rapae and Plutella xylostella resulted in significantly increased endogenous levels of JA, a central component in the octadecanoid signalling pathway that mediates induced plant defence. The levels of the intermediate 12-oxophyto-dienoic acid (OPDA) were significantly induced only after P. rapae feeding. Three species of parasitoid wasps, Cotesia glomerata, C. rubecula, and Diadegma semiclausum, differing in host range and host specificity, were tested for their behavioural responses to volatiles from herbivore-induced, JA-induced, and non-induced plants. All three species were attracted to volatiles from JA-induced plants compared with control plants; however, they preferred volatiles from herbivore-induced plants over volatiles from JA-induced plants. Attraction of C. glomerata depended on both timing and dose of JA application. JA-induced plants produced larger quantities of volatiles than herbivore-induced and control plants, indicating that not only quantity, but also quality of the volatile blend is important in the host-location behaviour of the wasps. PMID:19451186

Parasite biodiversity and its determinants in coastal marine teleost fishes of Brazil.

PubMed

Luque, J L; Mouillot, D; Poulin, R

2004-06-01

Recent studies of the forces behind the diversification of parasite assemblages have shed light on many aspects of parasite biodiversity. By using only parasite species richness as their measure of diversity, however, previous investigations have ignored the relatedness among parasite species and the taxonomic structure of the assemblages, which contain much information about their evolutionary origins. Here, we performed a comparative analysis across 50 species of fish from the coast of Brazil; we evaluated the effects of several host traits (body size, social behaviour, feeding habits, preference for benthic vs. pelagic habitats, depth range, and ability to enter brackish waters) on the diversity of their assemblages of metazoan parasites. As measures of diversity, we used parasite species richness, as well as the average taxonomic distinctness of the assemblage and its variance; the latter measures are based on the average taxonomic distance between any two parasite species in an assemblage. Unlike parasite species richness, taxonomic distinctness was unaffected by the number of host individuals examined per species. Fish body length proved to be the main predictor of parasite species richness, even when controlling for the confounding influences of host phylogeny and sampling effort, although it did not correlate with measures of parasite taxonomic distinctness. Predatory fish also had higher parasite species richness than planktivores, but this trend could not be confirmed using phylogenetically independent contrasts between host taxa. The main host feature associated with the taxonomic diversity of parasites was schooling behaviour, with schooling fish having more taxonomically diverse parasite assemblages than those of their non-schooling relatives. When focusing on endoparasite species only, both predatory feeding habits and a broad depth range were associated with the taxonomic distinctness of parasites. Our results suggest that certain host traits (i.e. body size) determine how many parasite species a host can accumulate over evolutionary time, whereas different host features influence the processes causing the taxonomic diversification of parasite assemblages.

Signatures of Pleiotropy, Economy and Convergent Evolution in a Domain-Resolved Map of Human–Virus Protein–Protein Interaction Networks

PubMed Central

Garamszegi, Sara; Franzosa, Eric A.; Xia, Yu

2013-01-01

A central challenge in host-pathogen systems biology is the elucidation of general, systems-level principles that distinguish host-pathogen interactions from within-host interactions. Current analyses of host-pathogen and within-host protein-protein interaction networks are largely limited by their resolution, treating proteins as nodes and interactions as edges. Here, we construct a domain-resolved map of human-virus and within-human protein-protein interaction networks by annotating protein interactions with high-coverage, high-accuracy, domain-centric interaction mechanisms: (1) domain-domain interactions, in which a domain in one protein binds to a domain in a second protein, and (2) domain-motif interactions, in which a domain in one protein binds to a short, linear peptide motif in a second protein. Analysis of these domain-resolved networks reveals, for the first time, significant mechanistic differences between virus-human and within-human interactions at the resolution of single domains. While human proteins tend to compete with each other for domain binding sites by means of sequence similarity, viral proteins tend to compete with human proteins for domain binding sites in the absence of sequence similarity. Independent of their previously established preference for targeting human protein hubs, viral proteins also preferentially target human proteins containing linear motif-binding domains. Compared to human proteins, viral proteins participate in more domain-motif interactions, target more unique linear motif-binding domains per residue, and contain more unique linear motifs per residue. Together, these results suggest that viruses surmount genome size constraints by convergently evolving multiple short linear motifs in order to effectively mimic, hijack, and manipulate complex host processes for their survival. Our domain-resolved analyses reveal unique signatures of pleiotropy, economy, and convergent evolution in viral-host interactions that are otherwise hidden in the traditional binary network, highlighting the power and necessity of high-resolution approaches in host-pathogen systems biology. PMID:24339775

Signatures of pleiotropy, economy and convergent evolution in a domain-resolved map of human-virus protein-protein interaction networks.

PubMed

Garamszegi, Sara; Franzosa, Eric A; Xia, Yu

2013-01-01

A central challenge in host-pathogen systems biology is the elucidation of general, systems-level principles that distinguish host-pathogen interactions from within-host interactions. Current analyses of host-pathogen and within-host protein-protein interaction networks are largely limited by their resolution, treating proteins as nodes and interactions as edges. Here, we construct a domain-resolved map of human-virus and within-human protein-protein interaction networks by annotating protein interactions with high-coverage, high-accuracy, domain-centric interaction mechanisms: (1) domain-domain interactions, in which a domain in one protein binds to a domain in a second protein, and (2) domain-motif interactions, in which a domain in one protein binds to a short, linear peptide motif in a second protein. Analysis of these domain-resolved networks reveals, for the first time, significant mechanistic differences between virus-human and within-human interactions at the resolution of single domains. While human proteins tend to compete with each other for domain binding sites by means of sequence similarity, viral proteins tend to compete with human proteins for domain binding sites in the absence of sequence similarity. Independent of their previously established preference for targeting human protein hubs, viral proteins also preferentially target human proteins containing linear motif-binding domains. Compared to human proteins, viral proteins participate in more domain-motif interactions, target more unique linear motif-binding domains per residue, and contain more unique linear motifs per residue. Together, these results suggest that viruses surmount genome size constraints by convergently evolving multiple short linear motifs in order to effectively mimic, hijack, and manipulate complex host processes for their survival. Our domain-resolved analyses reveal unique signatures of pleiotropy, economy, and convergent evolution in viral-host interactions that are otherwise hidden in the traditional binary network, highlighting the power and necessity of high-resolution approaches in host-pathogen systems biology.

Toxoplasma gondii influences aversive behaviors of female rats in an estrus cycle dependent manner.

PubMed

Golcu, Doruk; Gebre, Rahiwa Z; Sapolsky, Robert M

2014-08-01

The protozoan Toxoplasma gondii (T. gondii) manipulates the behavior of its rodent intermediate host to facilitate its passage to its feline definitive host. This is accomplished by a reduction of the aversive response that rodents show towards cat odors, which likely increases the predation risk. Females on average show similar changes as males. However, behaviors that relate to aversion and attraction are usually strongly influenced by the estrus cycle. In this study, we replicated behavioral effects of T. gondii in female rats, as well as expanded it to two novel behavioral paradigms. We also characterized the role of the estrus cycle in the behavioral effects of T. gondii on female rats. Uninfected females preferred to spend more time in proximity to rabbit rather than bobcat urine, and in a dark chamber rather than a lit chamber. Infected females lost both of these preferences, and also spent more time investigating social novelty (foreign bedding in their environment). Taken together, these data suggest that infection makes females less risk averse and more exploratory. Furthermore, this effect was influenced by the estrus cycle. Uninfected rats preferred rabbit urine to bobcat urine throughout the cycle except at estrus and metestrus. In contrast, infected rats lost this preference at every stage of the cycle except estrus. Commensurate with the possibility that this was a hormone-dependent effect, infected rats had elevated levels of circulating progesterone, a known anxiolytic. Copyright © 2014 Elsevier Inc. All rights reserved.

Toxoplasma gondii influences aversive behaviors of female rats in an estrus cycle dependent manner

PubMed Central

Golcu, Doruk; Gebre, Rahiwa Z.; Sapolsky, Robert M.

2016-01-01

The protozoan Toxoplasma gondii (T. gondii) manipulates the behavior of its rodent intermediate host to facilitate its passage to its feline definitive host. This is accomplished by a reduction of the aversive response that rodents show towards cat odors, which likely increases the predation risk. Females on average show similar changes as males. However, behaviors that relate to aversion and attraction are usually strongly influenced by the estrus cycle. In this study, we replicated behavioral effects of T. gondii in female rats, as well as expanded it to two novel behavioral paradigms. We also characterized the role of the estrus cycle in the behavioral effects of T. gondii on female rats. Uninfected females preferred to spend more time in proximity to rabbit rather than bobcat urine, and in a dark chamber rather than a lit chamber. Infected females lost both of these preferences, and also spent more time investigating social novelty (foreign bedding in their environment). Taken together, these data suggest that infection makes females less risk averse and more exploratory. Furthermore, this effect was influenced by the estrus cycle. Uninfected rats preferred rabbit urine to bobcat urine throughout the cycle except at estrus and metestrus. In contrast, infected rats lost this preference at every stage of the cycle except estrus. Commensurate with the possibility that this was a hormone-dependent effect, infected rats had elevated levels of circulating progesterone, a known anxiolytic. PMID:24907696

Differential growth forms of the sponge Biemna fortis govern the abundance of its associated brittle star Ophiactis modesta

NASA Astrophysics Data System (ADS)

Dahihande, Azraj S.; Thakur, Narsinh L.

2017-08-01

Marine intertidal regions are physically stressful habitats. In such an environment, facilitator species and positive interactions mitigate unfavorable conditions to the benefit of less tolerant organisms. In sponge-brittle star association, sponges effectively shelter brittle stars from biotic and abiotic stresses. The sponge, Biemna fortis (Topsent, 1897) was examined from two intertidal regions Anjuna and Mhapan along the Central West Coast of India for associated brittle star Ophiactis modesta (Brock, 1888) during 2013-2014. The study sites varied in suspended particulate matter (SPM). B. fortis at the high SPM habitat (Anjuna) had partially buried growth form and at the low SPM habitat (Mhapan) had massive growth form. O. modesta was abundantly associated with the massive growth form (50-259 individuals per 500 ml sponge) but rarely occurred in association with partially buried growth form (6-16 individuals per 500 ml sponge). In laboratory choice assay O. modesta showed equal preference to the chemical cues from both the growth forms of B. fortis. In addition, O. modesta showed significant preference to B. fortis compared to other sympatric sponges. These observations highlight the involvement of chemical cues in host recognition by O. modesta. Massive growth forms transplanted to the high SPM habitat were unable to survive but partially buried growth forms transplanted to the low SPM habitat were able to survive. Differential growth forms of the host sponge B. fortis at different abiotic stresses affect the abundance of the associated brittle star O. modesta.

Leaf Morphological Characters Can Be a Factor for Intra-Varietal Preference of Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) among Eggplant Varieties.

PubMed

Hasanuzzaman, Abu Tayeb Mohammad; Islam, Md Nazrul; Zhang, Yi; Zhang, Chen-Yang; Liu, Tong-Xian

2016-01-01

The sweetpotato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae) MEAM1, is considered a serious pest of horticultural and many other crops. While eggplant (Solanum melongena) is one of the most favored host plants, the whiteflies exhibit preferences among different varieties. We hypothesized that certain morphological leaf characteristics of different varieties, like leaf trichome density, trichome length, leaf lamina thickness and leaf color, may affect whitefly landing, feeding and oviposition. In this study, we investigated the variation in leaf morphological characters among selected eggplant varieties and evaluated the effect of these leaf characteristics in rendering eggplant varieties either susceptible or resistant to B. tabaci. We evaluated eight eggplant varieties in choice feeding tests, and we found that the varieties JinSheng Zilongchangqie (JSZ) and H149 were the highly preferred varieties with the highest numbers of whitefly adults and eggs. Significantly lower numbers of whitefly adult eggs were found on the resistant variety Tuo Lu Bamu (TLB). The varieties JinGuangbo Luqie (JGL), JinGuangbo Ziquanqie (JGZ), DaYang Ziguanqie (DYZ), QinXing Ziguanqie (QXZ), and QinXing Niuxinqie (QXN) were moderately favored by B. tabaci. Leaf trichome density, trichome length and leaf lamina thickness were positively correlated with numbers of whitefly adults and eggs. B. tabaci was less attracted to the leaves that reflect long and middle wavelength light (higher R and G values) than to the bright green leaves (medium G value), but the short wavelength light (higher B value) had no significant effect on whitefly preference. The degree of hue had a positive effect, and saturation and brightness had a negative effect on whitefly attraction.

Host–guest complexes between cryptophane-C and chloromethanes revisited

PubMed Central

Takacs, Z; Soltesova, M; Kowalewski, J; Lang, J; Brotin, T; Dutasta, J-P

2013-01-01

Cryptophane-C is composed of two nonequivalent cyclotribenzylene caps, one of which contains methoxy group substituents on the phenyl rings. The two caps are connected by three OCH2CH2O linkers in an anti arrangement. Host–guest complexes of cryptophane-C with dichloromethane and chloroform in solution were investigated in detail by nuclear magnetic resonance techniques and density functional theory (DFT) calculations. Variable temperature proton and carbon-13 spectra show a variety of dynamic processes, such as guest exchange and host conformational transitions. The guest exchange was studied quantitatively by exchange spectroscopy measurements or by line-shape analysis. The conformational preferences of the guest-containing host were interpreted through cross-relaxation measurements, providing evidence of the gauche+2 and gauche−2 conformations of the linkers. In addition, the mobility of the chloroform guest inside the cavity was studied by carbon-13 relaxation experiments. Combining different types of evidence led to a detailed picture of molecular recognition, interpreted in terms of conformational selection. Copyright © 2012 John Wiley & Sons, Ltd. PMID:23132654

Associative learning for danger avoidance nullifies innate positive chemotaxis to host olfactory stimuli in a parasitic wasp

NASA Astrophysics Data System (ADS)

Benelli, Giovanni; Stefanini, Cesare; Giunti, Giulia; Geri, Serena; Messing, Russell H.; Canale, Angelo

2014-09-01

Animals rely on associative learning for a wide range of purposes, including danger avoidance. This has been demonstrated for several insects, including cockroaches, mosquitoes, drosophilid flies, paper wasps, stingless bees, bumblebees and honeybees, but less is known for parasitic wasps. We tested the ability of Psyttalia concolor (Hymenoptera: Braconidae) females to associate different dosages of two innately attractive host-induced plant volatiles (HIPVs), ethyl octanoate and decanal, with danger (electric shocks). We conducted an associative treatment involving odours and shocks and two non-associative controls involving shocks but not odours and odours but not shocks. In shock-only and odour-only trained wasps, females preferred on HIPV-treated than on blank discs. In associative-trained wasps, however, P. concolor's innate positive chemotaxis for HIPVs was nullified (lowest HIPV dosage tested) or reversed (highest HIPV dosage tested). This is the first report of associative learning of olfactory cues for danger avoidance in parasitic wasps, showing that the effects of learning can override innate positive chemotaxes.

Eco-evolutionary spatial dynamics in the Glanville fritillary butterfly.

PubMed

Hanski, Ilkka A

2011-08-30

Demographic population dynamics, gene flow, and local adaptation may influence each other and lead to coupling of ecological and evolutionary dynamics, especially in species inhabiting fragmented heterogeneous environments. Here, I review long-term research on eco-evolutionary spatial dynamics in the Glanville fritillary butterfly inhabiting a large network of approximately 4,000 meadows in Finland. The metapopulation persists in a balance between frequent local extinctions and recolonizations. The genetic spatial structure as defined by neutral markers is much more coarse-grained than the demographic spatial structure determined by the fragmented habitat, yet small-scale spatial structure has important consequences for the dynamics. I discuss three examples of eco-evolutionary spatial dynamics. (i) Extinction-colonization metapopulation dynamics influence allele frequency changes in the phosphoglucose isomerase (Pgi) gene, which leads to strong associations between genetic variation in Pgi and dispersal, recolonization, and local population dynamics. (ii) Inbreeding in local populations increases their risk for extinction, whereas reciprocal effects between inbreeding, population size, and emigration represent likely eco-evolutionary feedbacks. (iii) Genetically determined female oviposition preference for two host plant species exhibits a cline paralleling a gradient in host plant relative abundances, and host plant preference of dispersing females in relation to the host plant composition of habitat patches influences immigration (gene flow) and recolonization (founder events). Eco-evolutionary spatial dynamics in heterogeneous environments may not lead to directional evolutionary changes unless the environment itself changes, but eco-evolutionary dynamics may contribute to the maintenance of genetic variation attributable to fluctuating selection in space and time.

Breaking the DNA-binding code of Ralstonia solanacearum TAL effectors provides new possibilities to generate plant resistance genes against bacterial wilt disease.

PubMed

de Lange, Orlando; Schreiber, Tom; Schandry, Niklas; Radeck, Jara; Braun, Karl Heinz; Koszinowski, Julia; Heuer, Holger; Strauß, Annett; Lahaye, Thomas

2013-08-01

Ralstonia solanacearum is a devastating bacterial phytopathogen with a broad host range. Ralstonia solanacearum injected effector proteins (Rips) are key to the successful invasion of host plants. We have characterized Brg11(hrpB-regulated 11), the first identified member of a class of Rips with high sequence similarity to the transcription activator-like (TAL) effectors of Xanthomonas spp., collectively termed RipTALs. Fluorescence microscopy of in planta expressed RipTALs showed nuclear localization. Domain swaps between Brg11 and Xanthomonas TAL effector (TALE) AvrBs3 (avirulence protein triggering Bs3 resistance) showed the functional interchangeability of DNA-binding and transcriptional activation domains. PCR was used to determine the sequence of brg11 homologs from strains infecting phylogenetically diverse host plants. Brg11 localizes to the nucleus and activates promoters containing a matching effector-binding element (EBE). Brg11 and homologs preferentially activate promoters containing EBEs with a 5' terminal guanine, contrasting with the TALE preference for a 5' thymine. Brg11 and other RipTALs probably promote disease through the transcriptional activation of host genes. Brg11 and the majority of homologs identified in this study were shown to activate similar or identical target sequences, in contrast to TALEs, which generally show highly diverse target preferences. This information provides new options for the engineering of plants resistant to R. solanacearum. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Sex-biased oviposition by a nursery pollinator on a gynodioecious host plant: Implications for breeding system evolution and evolution of mutualism.

PubMed

Doubleday, Laura A D; Adler, Lynn S

2017-07-01

Dioecy, a breeding system where individual plants are exclusively male or female, has evolved repeatedly. Extensive theory describes when dioecy should arise from hermaphroditism, frequently through gynodioecy, where females and hermaphrodites coexist, and when gynodioecy should be stable. Both pollinators and herbivores often prefer the pollen-bearing sex, with sex-specific fitness effects that can affect breeding system evolution. Nursery pollination, where adult insects pollinate flowers but their larvae feed on plant reproductive tissues, is a model for understanding mutualism evolution but could also yield insights into plant breeding system evolution. We studied a recently established nursery pollination interaction between native Hadena ectypa moths and introduced gynodioecious Silene vulgaris plants in North America to assess whether oviposition was biased toward females or hermaphrodites, which traits were associated with oviposition, and the effect of oviposition on host plant fitness. Oviposition was hermaphrodite-biased and associated with deeper flowers and more stems. Sexual dimorphism in flower depth, a trait also associated with oviposition on the native host plant ( Silene stellata ), explained the hermaphrodite bias. Egg-receiving plants experienced more fruit predation than plants that received no eggs, but relatively few fruits were lost, and egg receipt did not significantly alter total fruit production at the plant level. Oviposition did not enhance pollination; egg-receiving flowers usually failed to expand and produce seeds. Together, our results suggest that H. ectypa oviposition does not exert a large fitness cost on host plants, sex-biased interactions can emerge from preferences developed on a hermaphroditic host species, and new nursery pollination interactions can arise as negative or neutral rather than as mutualistic for the plant.

Soil moisture and chemistry influence diversity of ectomycorrhizal fungal communities associating with willow along an hydrologic gradient.

PubMed

Erlandson, Sonya R; Savage, Jessica A; Cavender-Bares, Jeannine M; Peay, Kabir G

2016-01-01

Influences of soil environment and willow host species on ectomycorrhizal fungi communities was studied across an hydrologic gradient in temperate North America. Soil moisture, organic matter and pH strongly predicted changes in fungal community composition. In contrast, increased fungal richness strongly correlated with higher plant-available phosphorus. The 93 willow trees sampled for ectomycorrhizal fungi included seven willow species. Host identity did not influence fungal richness or community composition, nor was there strong evidence of willow host preference for fungal species. Network analysis suggests that these mutualist interaction networks are not significantly nested or modular. Across a strong environmental gradient, fungal abiotic niche determined the fungal species available to associate with host plants within a habitat. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Analysis of host preference and geographical distribution of Anastrepha suspensa (Diptera: Tephritidae) using phylogenetic analyses of mitochondrial cytochrome oxidase I DNA sequence data.

PubMed

Boykin, L M; Shatters, R G; Hall, D G; Burns, R E; Franqui, R A

2006-10-01

Anastrepha suspensa (Loew) is an economically important pest, restricted to the Greater Antilles and southern Florida. It infests a wide variety of hosts and is of quarantine importance in citrus, a multi-million dollar industry in Florida. The observed recent increase in citrus infested with A. suspensa in Florida has raised questions regarding host-specificity of certain populations and genetic diversity of the pest throughout its geographical distribution. Cytochrome oxidase I (COI) DNA sequence data was used to characterize the genetic diversity of A. suspensa from Florida and Caribbean populations reared from different host plants. Maximum likelihood and Bayesian phylogenetic methods were used to analyse COI data. Sequence variation among mitochondrial COI genes from 107 A. suspensa samples collected throughout Florida and the Caribbean ranged between 0 and 10% and placed all A. suspensa as a monophyletic group that united all A. suspensa in a clade sister to a Central American group of the A. fraterculus paraphyletic species complex. The most likely tree of the COI locus indicated that COI sequence variation was too low to provide resolution at the subspecies level, therefore monophyletic groups based on host-plant use, geography (Florida, Jamaica, Cayman Islands, Puerto Rico or Dominican Republic) or population sampled are not supported. This result indicates that either no population segregation has occurred based on these biological or geographical distinctions and that this is a generalist, polyphagous invasive genotype. Alternatively, if populations are distinct, the segregation event was more recent than can be distinguished based on COI sequence variation.

Determinants of the geographic distribution of Puumala virus and Lyme borreliosis infections in Belgium.

PubMed

Linard, Catherine; Lamarque, Pénélope; Heyman, Paul; Ducoffre, Geneviève; Luyasu, Victor; Tersago, Katrien; Vanwambeke, Sophie O; Lambin, Eric F

2007-05-02

Vector-borne and zoonotic diseases generally display clear spatial patterns due to different space-dependent factors. Land cover and land use influence disease transmission by controlling both the spatial distribution of vectors or hosts, and the probability of contact with susceptible human populations. The objective of this study was to combine environmental and socio-economic factors to explain the spatial distribution of two emerging human diseases in Belgium, Puumala virus (PUUV) and Lyme borreliosis. Municipalities were taken as units of analysis. Negative binomial regressions including a correction for spatial endogeneity show that the spatial distribution of PUUV and Lyme borreliosis infections are associated with a combination of factors linked to the vector and host populations, to human behaviours, and to landscape attributes. Both diseases are associated with the presence of forests, which are the preferred habitat for vector or host populations. The PUUV infection risk is higher in remote forest areas, where the level of urbanisation is low, and among low-income populations. The Lyme borreliosis transmission risk is higher in mixed landscapes with forests and spatially dispersed houses, mostly in wealthy peri-urban areas. The spatial dependence resulting from a combination of endogenous and exogenous processes could be accounted for in the model on PUUV but not for Lyme borreliosis. A large part of the spatial variation in disease risk can be explained by environmental and socio-economic factors. The two diseases not only are most prevalent in different regions but also affect different groups of people. Combining these two criteria may increase the efficiency of information campaigns through appropriate targeting.

Culicoides biting midges (Diptera, Ceratopogonidae) in various climatic zones of Russia and adjacent lands.

PubMed

Sprygin, A V; Fiodorova, O A; Babin, Yu Yu; Elatkin, N P; Mathieu, B; England, M E; Kononov, A V

2014-12-01

Culicoides biting midges play an important role in the epidemiology of many vector-borne infections, including bluetongue virus, an internationally important virus of ruminants. The territory of the Russian Federation includes regions with diverse climatic conditions and a wide range of habitats suitable for Culicoides. This review summarizes available data on Culicoides studied in the Russian Federation covering geographically different regions, as well as findings from adjacent countries. Previous literature on species composition, ranges of dominant species, breeding sites, and host preferences is reviewed and suggestions made for future studies to elucidate vector-virus relationships. © 2014 The Society for Vector Ecology.

Making the most of your host: the Metrosideros-feeding psyllids (Hemiptera, Psylloidea) of the Hawaiian Islands

PubMed Central

Percy, Diana M.

2017-01-01

Abstract The Hawaiian psyllids (Psylloidea, Triozidae) feeding on Metrosideros (Myrtaceae) constitute a remarkable radiation of more than 35 species. This monophyletic group has diversified on a single, highly polymorphic host plant species, Metrosideros polymorpha. Eleven Metrosideros-feeding species included in the Insects of Hawaii by Zimmerman are redescribed, and an additional 25 new species are described. Contrary to previous classifications that placed the Metrosideros-feeders in two genera, Trioza Foerster, 1848 and Kuwayama Crawford, 1911, all 36 named species are placed in Pariaconus Enderlein, 1926; and the relationship of this genus to other Pacific taxa within the family Triozidae, and other Austro-Pacific taxa feeding on host plants in Myrtaceae is clarified. The processes of diversification in Pariaconus include shifts in galling habit, geographic isolation within and between islands, and preferences for different morphotypes of the host plant. Four species groups are recognized: the bicoloratus and minutus groups are free-living or form pit galls, and together with the kamua group (composing all of the Kauai species) form a basal assemblage; the more derived closed gall species in the ohialoha group are found on all major islands except Kauai. The diversification of Pariaconus has likely occurred over several million years. Within island diversification is exemplified in the kamua group, and within species variation in the ohialoha group, but species discovery rates suggest this radiation remains undersampled. Mitochondrial DNA barcodes are provided for 28 of the 36 species. Genetic divergence, intraspecific genetic structure, and parallel evolution of different galling biologies and morphological traits are discussed within a phylogenetic framework. Outgroup analysis for the genus Pariaconus and ancestral character state reconstruction suggest pit-galling may be the ancestral state, and the closest outgroups are Palaearctic-Australasian taxa rather than other Pacific Metrosideros-feeders. PMID:28325970

Evidence for host preference of Macrophomina phaseolina on strawberry

USDA-ARS?s Scientific Manuscript database

With the transition from broadcast preplant fumigation to individual bed treatment using alternative fumigants, M. phaseolina has become an emerging disease problem in California strawberry production, causing serious losses in all production districts. Population analysis using SSR markers of 68 i...

Single nucleotide polymorphisms in the Mycobacterium bovis genome resolve phylogenetic relationships

USDA-ARS?s Scientific Manuscript database

Mycobacterium bovis isolates carry restricted allelic variation yet exhibit a range of disease phenotypes and host preferences. Conventional genotyping methods target small hyper-variable regions of their genome and provide anonymous biallelic information insufficient to develop phylogeny. To resolv...

Plant scents modify innate colour preference in foraging swallowtail butterflies.

PubMed

Yoshida, Mina; Itoh, Yuki; Ômura, Hisashi; Arikawa, Kentaro; Kinoshita, Michiyo

2015-07-01

Flower-visiting insects exhibit innate preferences for particular colours. A previous study demonstrated that naive Papilio xuthus females prefer yellow and red, whereas males are more attracted to blue. Here, we demonstrate that the innate colour preference can be modified by olfactory stimuli in a sexually dimorphic manner. Naive P. xuthus were presented with four coloured discs: blue, green, yellow and red. The innate colour preference (i.e. the colour first landed on) of the majority of individuals was blue. When scent from essential oils of either orange flower or lily was introduced to the room, females' tendency to select the red disc increased. Scents of lavender and flowering potted Hibiscus rosa-sinensis, however, were less effective. Interestingly, the odour of the non-flowering larval host plant, Citrus unshiu, shifted the preference to green in females. In males, however, all plant scents were less effective than in females, such that blue was always the most favoured colour. These observations indicate that interactions between visual and olfactory cues play a more prominent role in females. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

The demography of words: The global decline in non-numeric fertility preferences, 1993-2011.

PubMed

Frye, Margaret; Bachan, Lauren

2017-07-01

This paper examines the decline in non-numeric responses to questions about fertility preferences among women in the developing world. These types of response-such as 'don't know' or 'it's up to God'-have often been interpreted through the lens of fertility transition theory as an indication that reproduction has not yet entered women's 'calculus of conscious choice'. However, this has yet to be investigated cross-nationally and over time. Using 19 years of data from 32 countries, we find that non-numeric fertility preferences decline most substantially in the early stages of a country's fertility transition. Using country-specific and multilevel models, we explore the individual- and contextual-level characteristics associated with women's likelihood of providing a non-numeric response to questions about their fertility preferences. Non-numeric fertility preferences are influenced by a host of social factors, with educational attainment and knowledge of contraception being the most robust and consistent predictors.

Amoeba host-Legionella synchronization of amino acid auxotrophy and its role in bacterial adaptation and pathogenic evolution.

PubMed

Price, Christopher T D; Richards, Ashley M; Von Dwingelo, Juanita E; Samara, Hala A; Abu Kwaik, Yousef

2014-02-01

Legionella pneumophila, the causative agent of Legionnaires' disease, invades and proliferates within a diverse range of free-living amoeba in the environment, but upon transmission to humans, the bacteria hijack alveolar macrophages. Intracellular proliferation of L. pneumophila in two evolutionarily distant hosts is facilitated by bacterial exploitation of conserved host processes that are targeted by bacterial protein effectors injected into the host cell. A key aspect of microbe-host interaction is microbial extraction of nutrients from the host, but understanding of this is still limited. AnkB functions as a nutritional virulence factor and promotes host proteasomal degradation of polyubiquitinated proteins generating gratuitous levels of limiting host cellular amino acids. Legionella pneumophila is auxotrophic for several amino acids including cysteine, which is a metabolically preferred source of carbon and energy during intracellular proliferation, but is limiting in both amoebae and humans. We propose that synchronization of bacterial amino acids auxotrophy with the host is a driving force in pathogenic evolution and nutritional adaptation of L. pneumophila and other intracellular bacteria to life within the host cell. Understanding microbial strategies of nutrient generation and acquisition in the host will provide novel antimicrobial strategies to disrupt pathogen access to essential sources of carbon and energy. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

Prioritizing like nuclear smugglers

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

Erickson, S A

1999-07-01

An individual or group attempting to smuggle nuclear material out of a country has a choice of what border crossing to use and how to do it. If it is possible to think like a smuggler and determine what preferences one would have, then we could protect those smuggler-preferred border crossings first. Thinking like a smuggler requires that one understand a host of things: who is likely to smuggle and what might they have obtained, where they might have gotten it, and where they would like to deliver or sell it, how they will attempt to pass customs, how theymore » might travel on both sides of the border, and what influences they might have on customs officials. After collecting data on criminology, geography, and much else, it is necessary to paste the data together into scenarios to ensure that self-consistent smuggling plans are created. These lead to counter-smuggling opportunities. Smuggling by amateurs turns out to be of a different class than professional smuggling, and needs to be countered differently. This work also assists in formulating key policy questions useful to guide counter-smuggling efforts. This methodology was developed for DOE/NN-43 for assistance with prioritization within the Second Line of Defense program.« less

Sampling Design Influences the Observed Dominance of Culex tritaeniorhynchus: Considerations for Future Studies of Japanese Encephalitis Virus Transmission

PubMed Central

Lord, Jennifer S.; Al-Amin, Hasan Mohammad; Chakma, Sumit; Alam, Mohammad Shafiul; Gurley, Emily S.; Pulliam, Juliet R. C.

2016-01-01

Mosquito sampling during Japanese encephalitis virus (JEV)-associated studies, particularly in India, has usually been conducted via aspirators or light traps to catch mosquitoes around cattle, which are dead-end hosts for JEV. High numbers of Culex tritaeniorhynchus, relative to other species, have often been caught during these studies. Less frequently, studies have involved sampling outdoor resting mosquitoes. We aimed to compare the relative abundance of mosquito species between these two previously used mosquito sampling methods. From September to December 2013 entomological surveys were undertaken in eight villages in a Japanese encephalitis (JE) endemic area of Bangladesh. Light traps were used to collect active mosquitoes in households, and resting boxes and a Bina Pani Das hop cage were used near oviposition sites to collect resting mosquitoes. Numbers of humans and domestic animals present in households where light traps were set were recorded. In five villages Cx. tritaeniorhynchus was more likely to be selected from light trap samples near hosts than resting collection samples near oviposition sites, according to log odds ratio tests. The opposite was true for Cx. pseudovishnui and Armigeres subalbatus, which can also transmit JEV. Culex tritaeniorhynchus constituted 59% of the mosquitoes sampled from households with cattle, 28% from households without cattle and 17% in resting collections. In contrast Cx. pseudovishnui constituted 5.4% of the sample from households with cattle, 16% from households with no cattle and 27% from resting collections, while Ar. subalbatus constituted 0.15%, 0.38%, and 8.4% of these samples respectively. These observations may be due to differences in timing of biting activity, host preference and host-seeking strategy rather than differences in population density. We suggest that future studies aiming to implicate vector species in transmission of JEV should consider focusing catches around hosts able to transmit JEV. PMID:26726881

Sampling Design Influences the Observed Dominance of Culex tritaeniorhynchus: Considerations for Future Studies of Japanese Encephalitis Virus Transmission.

PubMed

Lord, Jennifer S; Al-Amin, Hasan Mohammad; Chakma, Sumit; Alam, Mohammad Shafiul; Gurley, Emily S; Pulliam, Juliet R C

2016-01-01

Mosquito sampling during Japanese encephalitis virus (JEV)-associated studies, particularly in India, has usually been conducted via aspirators or light traps to catch mosquitoes around cattle, which are dead-end hosts for JEV. High numbers of Culex tritaeniorhynchus, relative to other species, have often been caught during these studies. Less frequently, studies have involved sampling outdoor resting mosquitoes. We aimed to compare the relative abundance of mosquito species between these two previously used mosquito sampling methods. From September to December 2013 entomological surveys were undertaken in eight villages in a Japanese encephalitis (JE) endemic area of Bangladesh. Light traps were used to collect active mosquitoes in households, and resting boxes and a Bina Pani Das hop cage were used near oviposition sites to collect resting mosquitoes. Numbers of humans and domestic animals present in households where light traps were set were recorded. In five villages Cx. tritaeniorhynchus was more likely to be selected from light trap samples near hosts than resting collection samples near oviposition sites, according to log odds ratio tests. The opposite was true for Cx. pseudovishnui and Armigeres subalbatus, which can also transmit JEV. Culex tritaeniorhynchus constituted 59% of the mosquitoes sampled from households with cattle, 28% from households without cattle and 17% in resting collections. In contrast Cx. pseudovishnui constituted 5.4% of the sample from households with cattle, 16% from households with no cattle and 27% from resting collections, while Ar. subalbatus constituted 0.15%, 0.38%, and 8.4% of these samples respectively. These observations may be due to differences in timing of biting activity, host preference and host-seeking strategy rather than differences in population density. We suggest that future studies aiming to implicate vector species in transmission of JEV should consider focusing catches around hosts able to transmit JEV.

An epidemiological model of internet worms with hierarchical dispersal and spatial clustering of hosts.

PubMed

Hiebeler, David E; Audibert, Andrew; Strubell, Emma; Michaud, Isaac J

2017-04-07

Beginning in 2001, many instances of malicious software known as Internet worms have been using biological strategies such as hierarchical dispersal to seek out and spread to new susceptible hosts more efficiently. We measured the distribution of potentially susceptible hosts in the space of Internet addresses to determine their clustering. We have used the results to construct a full-size simulated Internet with 2 32 hosts with mean and variance of susceptible hosts chosen to match our measurements at multiple spatial scales. Epidemiological simulations of outbreaks among the roughly 2.8×10 6 susceptible hosts on this full-sized network show that local preference scanning greatly increases the chances for an infected host to locate and infect other susceptible hosts by a factor of as much as several hundred. However, once deploying this strategy, the overall success of a worm is relatively insensitive to the details of its dispersal strategy over a wide range of parameters. In addition, although using localized interactions may allow malicious software to spread more rapidly or to more hosts on average, it can also lead to increased variability in infection levels among replicate simulations. Using such dispersal strategies may therefore be a high risk, high reward strategy for the authors of such software. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Intestinal Microbiota of Tadpoles Differs from Those of Syntopic Aquatic Invertebrates.

PubMed

Lyra, Mariana L; Bletz, Molly C; Haddad, Célio F B; Vences, Miguel

2017-11-20

Bacterial communities associated to eukaryotes play important roles in the physiology, development, and health of their hosts. Here, we examine the intestinal microbiota in tadpoles and aquatic invertebrates (insects and gastropods) to better understand the degree of specialization in the tadpole microbiotas. Samples were collected at the same time in one pond, and the V4 region of the bacterial 16S rRNA gene was sequenced with Illumina amplicon sequencing. We found that bacterial richness and diversity were highest in two studied snail individuals, intermediate in tadpoles, and lowest in the four groups of aquatic insects. All groups had substantial numbers of exclusive bacterial operational taxonomic units (OTUs) in their guts, but also shared a high proportion of OTUs, probably corresponding to transient environmental bacteria. Significant differences were found for all pairwise comparisons of tadpoles and snails with the major groups of insects, but not among insect groups or between snails and tadpoles. The similarity between tadpoles and snails may be related to similar feeding mode as both snails and tadpoles scratch biofilms and algae from surfaces; however, this requires confirmation due to low sample sizes. Overall, the gut microbiota differences found among syntopic aquatic animals are likely shaped by both food preferences and host identity.

Has Sarcocystis neurona Dubey et al., 1991 (Sporozoa: Apicomplexa: Sarcocystidae) cospeciated with its intermediate hosts?

PubMed

Elsheikha, Hany M

2009-08-26

The question of how Sarcocystis neurona is able to overcome species barrier and adapt to new hosts is central to the understanding of both the evolutionary origin of S. neurona and the prediction of its field host range. Therefore, it is worth reviewing current knowledge on S. neurona host specificity. The available host range data for S. neurona are discussed in relation to a subject of evolutionary importance-specialist or generalist and its implications to understand the strategies of host adaptation. Current evidences demonstrate that a wide range of hosts exists for S. neurona. This parasite tends to be highly specific for its definitive host but much less so for its intermediate host (I.H.). The unique specificity of S. neurona for its definitive host may be mediated by a probable long coevolutionary relationship of the parasite and carnivores in a restricted ecological niche 'New World'. This might be taken as evidence that carnivores are the 'original' host group for S. neurona. Rather, the capacity of S. neurona to exploit an unusually large number of I.H. species probably indicates that S. neurona maintains non-specificity to its I.H. as an adaptive response to insure the survival of the parasite in areas in which the 'preferred' host is not available. This review concludes with the view that adaptation of S. neurona to a new host is a complex interplay that involves a large number of determinants.

Derepression of the Plant Chromovirus LORE1 Induces Germline Transposition in Regenerated Plants

PubMed Central

Fukai, Eigo; Umehara, Yosuke; Sato, Shusei; Endo, Makoto; Kouchi, Hiroshi; Hayashi, Makoto; Stougaard, Jens; Hirochika, Hirohiko

2010-01-01

Transposable elements represent a large proportion of the eukaryotic genomes. Long Terminal Repeat (LTR) retrotransposons are very abundant and constitute the predominant family of transposable elements in plants. Recent studies have identified chromoviruses to be a widely distributed lineage of Gypsy elements. These elements contain chromodomains in their integrases, which suggests a preference for insertion into heterochromatin. In turn, this preference might have contributed to the patterning of heterochromatin observed in host genomes. Despite their potential importance for our understanding of plant genome dynamics and evolution, the regulatory mechanisms governing the behavior of chromoviruses and their activities remain largely uncharacterized. Here, we report a detailed analysis of the spatio-temporal activity of a plant chromovirus in the endogenous host. We examined LORE1a, a member of the endogenous chromovirus LORE1 family from the model legume Lotus japonicus. We found that this chromovirus is stochastically de-repressed in plant populations regenerated from de-differentiated cells and that LORE1a transposes in the male germline. Bisulfite sequencing of the 5′ LTR and its surrounding region suggests that tissue culture induces a loss of epigenetic silencing of LORE1a. Since LTR promoter activity is pollen specific, as shown by the analysis of transgenic plants containing an LTR::GUS fusion, we conclude that male germline-specific LORE1a transposition in pollen grains is controlled transcriptionally by its own cis-elements. New insertion sites of LORE1a copies were frequently found in genic regions and show no strong insertional preferences. These distinctive novel features of LORE1 indicate that this chromovirus has considerable potential for generating genetic and epigenetic diversity in the host plant population. Our results also define conditions for the use of LORE1a as a genetic tool. PMID:20221264

VOCs-Mediated Location of Olive Fly Larvae by the Braconid Parasitoid Psyttalia concolor: A Multivariate Comparison among VOC Bouquets from Three Olive Cultivars

PubMed Central

Giunti, Giulia; Benelli, Giovanni; Conte, Giuseppe; Mele, Marcello; Caruso, Giovanni; Gucci, Riccardo; Flamini, Guido; Canale, Angelo

2016-01-01

Herbivorous activity induces plant indirect defenses, as the emission of herbivorous-induced plant volatiles (HIPVs), which could be used by parasitoids for host location. Psyttalia concolor is a larval pupal endoparasitoid, attacking a number of tephritid flies including B. oleae. In this research, we investigated the olfactory cues routing host location behavior of P. concolor towards B. oleae larvae infesting three different olive cultivars. VOCs from infested and healthy fruits were identified using GC-MS analyses. In two-choice behavioral assays, P. concolor females preferred infested olive cues, which also evoked ovipositional probing by female wasps. GC-MS analysis showed qualitative and quantitative differences among volatiles emitted by infested and healthy olives. Volatile emissions were peculiar for each cultivar analyzed. Two putative HIPVs were detected in infested fruits, regardless of the cultivar, the monoterpene (E)-β-ocimene, and the sesquiterpene (E-E)-α-farnesene. Our study adds basic knowledge to the behavioral ecology of P. concolor. From an applied point of view, the field application of the above-mentioned VOCs may help to enhance effectiveness of biological control programs and parasitoid mass-rearing techniques. PMID:26989691

Evaluation method for the potential functionome harbored in the genome and metagenome

PubMed Central

2012-01-01

Background One of the main goals of genomic analysis is to elucidate the comprehensive functions (functionome) in individual organisms or a whole community in various environments. However, a standard evaluation method for discerning the functional potentials harbored within the genome or metagenome has not yet been established. We have developed a new evaluation method for the potential functionome, based on the completion ratio of Kyoto Encyclopedia of Genes and Genomes (KEGG) functional modules. Results Distribution of the completion ratio of the KEGG functional modules in 768 prokaryotic species varied greatly with the kind of module, and all modules primarily fell into 4 patterns (universal, restricted, diversified and non-prokaryotic modules), indicating the universal and unique nature of each module, and also the versatility of the KEGG Orthology (KO) identifiers mapped to each one. The module completion ratio in 8 phenotypically different bacilli revealed that some modules were shared only in phenotypically similar species. Metagenomes of human gut microbiomes from 13 healthy individuals previously determined by the Sanger method were analyzed based on the module completion ratio. Results led to new discoveries in the nutritional preferences of gut microbes, believed to be one of the mutualistic representations of gut microbiomes to avoid nutritional competition with the host. Conclusions The method developed in this study could characterize the functionome harbored in genomes and metagenomes. As this method also provided taxonomical information from KEGG modules as well as the gene hosts constructing the modules, interpretation of completion profiles was simplified and we could identify the complementarity between biochemical functions in human hosts and the nutritional preferences in human gut microbiomes. Thus, our method has the potential to be a powerful tool for comparative functional analysis in genomics and metagenomics, able to target unknown environments containing various uncultivable microbes within unidentified phyla. PMID:23234305

Membrane perturbing properties of toxin mycolactone from Mycobacterium ulcerans

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

Lopez, Cesar A.; Unkefer, Clifford J.; Swanson, Basil I.

Mycolactone is the exotoxin produced by Mycobacterium ulcerans and is the virulence factor behind the neglected tropical disease Buruli ulcer. The toxin has a broad spectrum of biological effects within the host organism, stemming from its interaction with at least two molecular targets and the inhibition of protein uptake into the endoplasmic reticulum. Although it has been shown that the toxin can passively permeate into host cells, it is clearly lipophilic. Association with lipid carriers would have substantial implications for the toxin’s distribution within a host organism, delivery to cellular targets, diagnostic susceptibility, and mechanisms of pathogenicity. Yet the toxin’smore » interactions with, and distribution in, lipids are unknown. Herein we have used coarse-grained molecular dynamics simulations, guided by all-atom simulations, to study the interaction of mycolactone with pure and mixed lipid membranes. Using established techniques, we calculated the toxin’s preferential localization, membrane translocation, and impact on membrane physical and dynamical properties. The computed water-octanol partition coefficient indicates that mycolactone prefers to be in an organic phase rather than in an aqueous environment. Our results show that in a solvated membrane environment the exotoxin mainly localizes in the water-membrane interface, with a preference for the glycerol moiety of lipids, consistent with the reported studies that found it in lipid extracts of the cell. The calculated association constant to the model membrane is similar to the reported association constant for Wiskott-Aldrich syndrome protein. Mycolactone is shown to modify the physical properties of membranes, lowering the transition temperature, compressibility modulus, and critical line tension at which pores can be stabilized. It also shows a tendency to behave as a linactant, a molecule that localizes at the boundary between different fluid lipid domains in membranes and promotes inter-mixing of domains. This property has implications for the toxin’s cellular access, T-cell immunosuppression, and therapeutic potential.« less

Membrane perturbing properties of toxin mycolactone from Mycobacterium ulcerans

DOE PAGES

Lopez, Cesar A.; Unkefer, Clifford J.; Swanson, Basil I.; ...

2018-02-05

Mycolactone is the exotoxin produced by Mycobacterium ulcerans and is the virulence factor behind the neglected tropical disease Buruli ulcer. The toxin has a broad spectrum of biological effects within the host organism, stemming from its interaction with at least two molecular targets and the inhibition of protein uptake into the endoplasmic reticulum. Although it has been shown that the toxin can passively permeate into host cells, it is clearly lipophilic. Association with lipid carriers would have substantial implications for the toxin’s distribution within a host organism, delivery to cellular targets, diagnostic susceptibility, and mechanisms of pathogenicity. Yet the toxin’smore » interactions with, and distribution in, lipids are unknown. Herein we have used coarse-grained molecular dynamics simulations, guided by all-atom simulations, to study the interaction of mycolactone with pure and mixed lipid membranes. Using established techniques, we calculated the toxin’s preferential localization, membrane translocation, and impact on membrane physical and dynamical properties. The computed water-octanol partition coefficient indicates that mycolactone prefers to be in an organic phase rather than in an aqueous environment. Our results show that in a solvated membrane environment the exotoxin mainly localizes in the water-membrane interface, with a preference for the glycerol moiety of lipids, consistent with the reported studies that found it in lipid extracts of the cell. The calculated association constant to the model membrane is similar to the reported association constant for Wiskott-Aldrich syndrome protein. Mycolactone is shown to modify the physical properties of membranes, lowering the transition temperature, compressibility modulus, and critical line tension at which pores can be stabilized. It also shows a tendency to behave as a linactant, a molecule that localizes at the boundary between different fluid lipid domains in membranes and promotes inter-mixing of domains. This property has implications for the toxin’s cellular access, T-cell immunosuppression, and therapeutic potential.« less

Intensive trapping of blood-fed Anopheles darlingi in Amazonian Peru reveals unexpectedly high proportions of avian blood-meals.

PubMed

Moreno, Marta; Saavedra, Marlon P; Bickersmith, Sara A; Prussing, Catharine; Michalski, Adrian; Tong Rios, Carlos; Vinetz, Joseph M; Conn, Jan E

2017-02-01

Anopheles darlingi, the main malaria vector in the Neotropics, has been considered to be highly anthropophilic. However, many behavioral aspects of this species remain unknown, such as the range of blood-meal sources. Barrier screens were used to collect resting Anopheles darlingi mosquitoes from 2013 to 2015 in three riverine localities (Lupuna, Cahuide and Santa Emilia) in Amazonian Peru. Overall, the Human Blood Index (HBI) ranged from 0.58-0.87, with no significant variation among years or sites. Blood-meal analysis revealed that humans are the most common blood source, followed by avian hosts (Galliformes-chickens and turkeys), and human/Galliforme mixed-meals. The Forage Ratio and Selection Index both show a strong preference for Galliformes over humans in blood-fed mosquitoes. Our data show that 30% of An. darlingi fed on more than one host, including combinations of dogs, pigs, goats and rats. There appears to be a pattern of host choice in An. darlingi, with varying proportions of mosquitoes feeding only on humans, only on Galliformes and some taking mixed-meals of blood (human plus Galliforme), which was detected in the three sites in different years, indicating that there could be a structure to these populations based on blood-feeding preferences. Mosquito age, estimated in two localities, Lupuna and Cahuide, ranged widely between sites and years. This variation may reflect the range of local environmental factors that influence longevity or possibly potential changes in the ability of the mosquito to transmit the parasite. Of 6,204 resting An. darlingi tested for Plasmodium infection, 0.42% were infected with P. vivax. This study provides evidence for the first time of the usefulness of barrier screens for the collection of blood-fed resting mosquitoes to calculate the Human Blood Index (HBI) and other blood-meal sources in a neotropical malaria endemic setting.

Leishmania infection and host-blood feeding preferences of phlebotomine sandflies and canine leishmaniasis in an endemic European area, the Algarve Region in Portugal

PubMed Central

Maia, Carla; Dionísio, Lídia; Afonso, Maria Odete; Neto, Luís; Cristóvão, José Manuel; Campino, Lenea

2013-01-01

The Algarve Region (AR) in southern Portugal, which is an international tourist destination, has been considered an endemic region of zoonotic leishmaniasis caused by Leishmania infantum since the 1980s. In the present study, phlebotomine and canine surveys were conducted to identify sandfly blood meal sources and to update the occurrence of Leishmania infection in vectors and dogs. Four sandfly species were captured: Phlebotomus perniciosus, Phlebotomus ariasi, Phlebotomus sergenti and Sergentomyia minuta. In one P. perniciosus female, L. infantum DNA was detected. Blood meal tests showed that this species had no host preferences and was an opportunistic feeder. An overall canine leishmaniasis (CanL) seroprevalence of 16.06% was found; the seroprevalence was 3.88% in dogs housed in kennels and 40.63% in dogs that attended veterinary clinics. The simultaneous occurrence of dogs and P. perniciosus infected with L. infantum in the AR indicates that the region continues to be an endemic area for CanL. Our results reinforce the need for the systematic spatial distribution of phlebotomine populations and their Leishmania infection rates and the need to simultaneously perform pathogen monitoring in both invertebrate and vertebrate hosts to investigate the transmission, distribution and spreading of Leishmania infection. PMID:23827997

Oviposition by mutualistic seed-consuming pollinators reduces fruit abortion in a recently discovered pollination mutualism

PubMed Central

Song, Bo; Stöcklin, Jürg; Gao, Yong-Qian; Peng, De-Li; Song, Min-Shu; Sun, Hang

2016-01-01

A prerequisite for the evolutionary stability of pollinating seed-consuming mutualisms is that each partner benefits from the association. However, few studies of such mutualism have considered the benefit gained by the pollinators. Here, we determined how the pollinating seed-predators ensure the provisioning of their offspring in the recently discovered mutualism between Rheum nobile and Bradysia flies. The correlation between flower fate and fly oviposition was examined. Floral traits and patterns of variation in fruit abortion and fly oviposition were investigated to determine whether female flies exhibit preferences for particular flowers when laying eggs. Indole-3-acetic acid (IAA) was quantified to determine whether female flies manipulate host physiology. Flowers that flies oviposited on had a significantly lower probability of fruit abortion compared with intact flowers. Females did not exhibit oviposition preference for any of the floral traits examined. There was no significant correlation between fruit abortion and fly oviposition in terms of either flower position or timing of flowering. IAA concentrations in oviposited flowers were significantly higher than in intact flowers. Our results suggest that oviposition by the mutualistic seed-consuming pollinator Bradysia sp., greatly reduces the probability of fruit abortion of its host, R. nobile; this may be attributed to the manipulation of host physiology through regulating IAA levels. PMID:27418228

Endophagy of biting midges attacking cavity-nesting birds.

PubMed

Votýpka, J; Synek, P; Svobodová, M

2009-09-01

Feeding behaviour, host preferences and the spectrum of available hosts determine the role of vectors in pathogen transmission. Feeding preferences of blood-feeding Diptera depend on, among others factors, the willingness of flies to attack their hosts either in the open (exophagy) or in enclosed places (endophagy). As far as ornithophilic blood-feeding Diptera are concerned, the biting midges (Diptera: Ceratopogonidae) and blackflies (Diptera: Simuliidae) are generally considered to be strictly exophagous. We determined which blood-sucking Diptera enter nest cavities and feed on birds by placing sticky foil traps inside artificial nest boxes. A total of 667 females of eight species of biting midges of the genus Culicoides (Latreille, 1809) were captured on traps during 2006-2007, with Culicoides truncorum (Edwards, 1939) being the dominant species. DNA blood analyses of blood-engorged females proved that midges actually fed on birds nesting in the boxes. Three species were identified as endophagous: Culicoides truncorum, Culicoides pictipennis (Staeger, 1839), and Culicoides minutissimus (Zetterstedt, 1855). Our study represents the first evidence that ornithophilic biting midges are endophagous. The fact that we caught no blackflies in the bird boxes supports the exophagy of blackflies. We believe that our findings are important for surveillance programmes focusing on Diptera that transmit various bird pathogens.

Egg retention and dispersal activity in the parasitoid wasp, Trichogramma principium

PubMed Central

Reznik, S. Ya; Klyueva, N. Z.

2006-01-01

Effects of egg retention on movement and dispersal activity of Trichogramma principium (Hymenoptera, Trichogrammatidae) females were investigated under laboratory conditions. Individual females were observed during one minute in the absence of hosts. Movement activity and dispersal rate were estimated by the length of the track and by the distance from the start point, respectively. Before the test, all wasps during 2 – 4 days were presented with a possibility to parasitize a factitious laboratory host, Sitotroga cerealella Oliv. (Lepidoptera, Gelechiidae). Wasps that had parasitized before the test show significant reduction of spontaneous walking activity and dispersal rate when compared with females that refused to parasitize the non-preferred host (i.e. manifested egg retention). This effect cannot be considered as a direct arrestment reaction to the host because during the test period, no hosts were provided. Thus, egg retention results not only in temporal spread, but also in more intensive spatial dispersal of a group of simultaneously emerged females. PMID:19537969

Salmonella Typhimurium Enzymatically Landscapes the Host Intestinal Epithelial Cell (IEC) Surface Glycome to Increase Invasion*

PubMed Central

Park, Dayoung; Arabyan, Narine; Williams, Cynthia C.; Song, Ting; Mitra, Anupam; Weimer, Bart C.; Lebrilla, Carlito B.

2016-01-01

Although gut host-pathogen interactions are glycan-mediated processes, few details are known about the participating structures. Here we employ high-resolution mass spectrometric profiling to comprehensively identify and quantitatively measure the exact modifications of native intestinal epithelial cell surface N-glycans induced by S. typhimurium infection. Sixty minutes postinfection, select sialylated structures showed decreases in terms of total number and abundances. To assess the effect of cell surface mannosylation, we selectively rerouted glycan expression on the host using the alpha-mannosidase inhibitor, kifunensine, toward overexpression of high mannose. Under these conditions, internalization of S. typhimurium significantly increased, demonstrating that bacteria show preference for particular structures. Finally, we developed a novel assay to measure membrane glycoprotein turnover rates, which revealed that glycan modifications occur by bacterial enzyme activity rather than by host-derived restructuring strategies. This study is the first to provide precise structural information on how host N-glycans are altered to support S. typhimurium invasion. PMID:27754876

Fidelity and Promiscuity in an Ant-Plant Mutualism: A Case Study of Triplaris and Pseudomyrmex

PubMed Central

Sanchez, Adriana

2015-01-01

The association between the myrmecophyte Triplaris and ants of the genus Pseudomyrmex is an often-reported example of mutualism but no molecular studies have examined this association to date. In this study, the interspecific relationships of Triplaris were reconstructed using five molecular markers (two chloroplast and three nuclear), and the relationships of the associated Pseudomyrmex using two molecular regions (one mitochondrial and one nuclear). A data set including all known collections of plant hosts and resident ants was also compiled. The pattern of distribution of both organisms reveals that there are varying degrees of host specificity; most ants show broader host usage (promiscuous) but one species (P. dendroicus) is faithful to a single species of Triplaris. In most ant-plant interactions, host usage is not specific at the species level and preferences may result from geographical or ecological sorting. The specificity of P. dendroicus could be based on chemical recognition of the host they were raised on. PMID:26630384

New records of Ergasilus (Copepoda: Ergasilidae) in the Laurentian Great Lakes, including a lakewide review of records and host associations

USGS Publications Warehouse

Hudson, Patrick L.; Bowen, Charles A.; Stedman, Ralph M.

1994-01-01

Ergasilus nerkae was found infecting ninespine stickleback (Pungitius pungitius) in lakes Huron, Michigan, and Superior and threespine stickleback (Gasterosteus aculeatus) and round whitefish (Prosopium cylindraceum) in Lake Huron. Based upon the literature and study of archived material, we propose that E. nerkae is enzootic to the Great Lakes and that ninespine stickleback are a preferred host in Lake Huron. Prevalence of E. nerkae on ninespine stickleback increased from 17% in June to 68% in September, but mean intensity remained light. Prevalence and mean intensity increased with host length. Ergasilus luciopercarum is also reported on lake trout (Salvelinus namaycush) and largemouth bass (Micropterus salmoides) for the first time. Host-parasite records of Ergasilus spp. in North America are reviewed, biology and taxonomy are summarized, and a checklist of Great Lakes host-parasite-locality records is provided. At present, eight species of Ergasilus are known to infect 42 Great Lakes fish species.

Rubella viruses shift cellular bioenergetics to a more oxidative and glycolytic phenotype with a strain-specific requirement for glutamine.

PubMed

Bilz, Nicole C; Jahn, Kristin; Lorenz, Mechthild; Lüdtke, Anja; Hübschen, Judith M; Geyer, Henriette; Mankertz, Annette; Hübner, Denise; Liebert, Uwe G; Claus, Claudia

2018-06-27

The flexible regulation of cellular metabolic pathways enables cellular adaptation to changes in energy demand under conditions of stress such as posed by a virus infection. To analyze such an impact on cellular metabolism, rubella virus (RV) was used in this study. RV replication under selected substrate supplementation with glucose, pyruvate, and glutamine as essential nutrients for mammalian cells revealed its requirement for glutamine. The assessment of the mitochondrial respiratory (based on oxygen consumption rate, OCR) and glycolytic (based on extracellular acidification rate, ECAR) rate and capacity by respective stress tests through Seahorse technology enabled determination of the bioenergetic phenotype of RV-infected cells. Irrespective of the cellular metabolic background, RV infection induced a shift of the bioenergetic state of epithelial (Vero and A549) and endothelial (HUVEC) cells to a higher oxidative and glycolytic level. Interestingly there was a RV strain-specific, but genotype-independent demand for glutamine to induce a significant increase in metabolic activity. While glutaminolysis appeared to be rather negligible for RV replication, glutamine could serve as donor of its amide nitrogen in biosynthesis pathways for important metabolites. This study suggests that the capacity of rubella viruses to induce metabolic alterations could evolve differently during natural infection. Thus, changes in cellular bioenergetics represent an important component of virus-host interactions and could complement our understanding of the viral preference for a distinct host cell population. Importance RV pathologies, especially during embryonal development, could be connected with its impact on mitochondrial metabolism. With bioenergetic phenotyping we pursued a rather novel approach in virology. For the first time it was shown that a virus infection could shift the bioenergetics of its infected host cell to a higher energetic state. Notably, the capacity to induce such alterations varied among different RV isolates. Thus, our data adds viral adaptation of cellular metabolic activity to its specific needs as a novel aspect to virus-host evolution. Additionally, this study emphasizes the implementation of different viral strains in the study of virus-host interactions and the use of bioenergetic phenotyping of infected cells as a biomarker for virus-induced pathological alterations. Copyright © 2018 American Society for Microbiology.

Titer improvement of iso-migrastatin in selected heterologous Streptomyces hosts and related analysis of mRNA expression by quantitative RT–PCR

PubMed Central

Yang, Dong; Zhu, Xiangcheng; Wu, Xueyun; Feng, Zhiyang; Huang, Lei; Shen, Ben; Xu, Zhinan

2011-01-01

iso-Migrastatin (iso-MGS) has been actively pursued recently as an outstanding candidate of antimetastasis agents. Having characterized the iso-MGS biosynthetic gene cluster from its native producer Streptomyces platensis NRRL 18993, we have recently succeeded in producing iso-MGS in five selected heterologous Streptomyces hosts, albeit the low titers failed to meet expectations and cast doubt on the utility of this novel technique for large-scale production. To further explore and capitalize on the production capacity of these hosts, a thorough investigation of these five engineered strains with three fermentation media for iso-MGS production was undertaken. Streptomyces albus J1074 and Streptomyces lividans K4-114 were found to be preferred heterologous hosts, and subsequent analysis of carbon and nitrogen sources revealed that sucrose and yeast extract were ideal for iso-MGS production. After the initial optimization, the titers of iso-MGS in all five hosts were considerably improved by 3–18-fold in the optimized R2YE medium. Furthermore, the iso-MGS titer of S. albus J1074 (pBS11001) was significantly improved to 186.7 mg/L by a hybrid medium strategy. Addition of NaHCO3 to the latter finally afforded an optimized iso-MGS titer of 213.8 mg/L, about 5-fold higher than the originally reported system. With S. albus J1074 (pBS11001) as a model host, the expression of iso-MGS gene cluster in four different media was systematically studied via the quantitative RT–PCR technology. The resultant comparison revealed the correlation of gene expression and iso-MGS production for the first time; synchronous expression of the whole gene cluster was crucial for optimal iso-MGS production. These results reveal new insights into the iso-MGS biosynthetic machinery in heterologous hosts and provide the primary data to realize large-scale production of iso-MGS for further preclinical studies. PMID:21132287

Preferences of the peripheral olfactory system of Western Flower Thrips, Frankliniella occidentalis towards stereoisomers of common plant volatiles.

PubMed

Abdullah, Zayed S; Butt, Tariq M

Stereochemistry plays a significant role in structure-activity relationships of messenger chemicals. The ability to distinguish between enantiomers and geometric isomers, however, may be limited to certain stereoisomeric substances, depending on the receiver. In this study, we assessed the preference of the peripheral olfactometry system of Western Flower Thrips, F. occidentalis towards ubiquitously expressed host compounds, with a goal of establishing whether particular stereoisomers enhance host odour recognition. We demonstrate that the peripheral olfactory system of a highly polyphagous thysanopteran insect has evolved to become highly sensitive to a type of green leaf volatile, which is highly ubiquitous in the plant kingdom. We show that there is a significantly greater antennal response to the cis isomer, more so than the isomerisation by-product trans -3-hexen-1-ol. We demonstrate that the antennae of a highly polyphagous insect are capable of detecting common plant secondary metabolites in both enantiomeric forms.

Light environment and leaf characteristics affect distribution of Corythuca arcuata (Hemiptera: Tingidae).

PubMed

Barber, Nicholas A

2010-04-01

Insect herbivore abundances on host plants are influenced by both plant traits and the physical environment in which that plant grows. This study examined the role of the physical light environment and foliage characteristics in determining abundance of the lacebug Corythuca arcuata Say (Hemiptera: Tingidae) on Quercus alba L. I censused adult C. arcuata across a growing season, quantified leaf characteristics, and measured canopy cover over understory branches of mature Q. alba. Using an information-theoretic approach, a priori hypotheses of the relationship between light, plant traits, and C. arcuata abundance was evaluated. Abundance was best predicted by light environment and carbon content. Adult C. arcuata prefer trees growing under an open canopy and trees with low carbon content; abundance also positively correlated with leaf water content. Although carbon and water did not vary with light in this study, low carbon and high water content are often associated with shadier conditions, suggesting that C. arcuata faces a trade-off between preferences for physical habitat conditions and host plant characteristics.

Host size-dependent anisakid infection in Baltic cod Gadus morhua associated with differential food preferences.

PubMed

Zuo, Shaozhi; Huwer, Bastian; Bahlool, Qusay; Al-Jubury, Azmi; Daugbjerg Christensen, Nanna; Korbut, Rozalia; Kania, Per; Buchmann, Kurt

2016-06-15

A significant increase in the infection level of Baltic cod Gadus morhua with the anisakid nematode larvae Contracaecum osculatum and Pseudoterranova decipiens has been recorded during recent years due to the expanding local population of grey seals Halichoerus grypus, which act as final hosts for these parasites. Here, we report from an investigation of 368 cod (total length [TL] 6-49 cm; caught in ICES Subdivision 25) that the infection level of juvenile cod (TL 6-30 cm) with larvae of C. osculatum and P. decipiens is absent or very low, whereas it increases drastically in larger cod (TL 31-48 cm). A third nematode Hysterothylacium aduncum was rarely found. The study indicates that the prey animals for large cod act as transport hosts for the parasite larvae. Analyses of stomach contents of cod caught in the same area (2007-2014) showed that small benthic organisms (including polychaetes Harmothoë sarsi) are preferred food items by small cod, the isopod Saduria entomon is taken by all size classes, and sprat Sprattus sprattus are common prey items for cod larger than 30 cm. Parasitological investigations (microscopic and molecular analyses) of H. sarsi (100 specimens) and S. entomon (40 specimens) did not reveal infection in these invertebrates, but 11.6% of sprat (265 specimens examined) was shown to be infected with 1-8 C. osculatum third stage larvae per fish. Analyses of sprat stomach contents confirmed that copepods and cladocerans are the main food items of sprat. These observations suggest that the C. osculatum life cycle in the Baltic Sea includes grey seals as final hosts, sprat as the first transport host and cod as second transport host. It may be speculated that sprat obtain infection by feeding on copepods and/or cladocerans, which could serve as the first intermediate hosts. One cannot exclude the possibility that the size-dependent C. osculatum infection of cod may contribute (indirectly or directly) to the differential mortality of larger cod (>38 cm) compared to smaller cod (<30 cm) recently recorded in the Baltic cod population.

Perspectives of South American physicians hosting foreign rotators in emergency medicine

PubMed Central

2014-01-01

Background Emergency Medicine (EM) is increasingly becoming an international field. The number of fellowships in International EM in the USA is growing along with opportunities to complete international health electives (IHEs) during residency training. The impact on host institutions, however, has not been adequately investigated. The objective of this study is to assess the experience of several South American hospitals hosting foreign EM residents completing IHEs. Methods Anonymous, semi-structured one-on-one interviews were conducted with physicians working in Emergency Departments in three hospitals in Lima, Peru and one hospital in Buenos Aires, Argentina. All participants reported previously working with EM foreign rotators. Interviews were analyzed qualitatively and coded for common themes. Results Three department chairs, six residents, and 15 attending physicians were interviewed (total = 24). After qualitative analysis of interviews, two broad theme categories emerged: Benefits and Challenges. Most commonly reported benefits were knowledge sharing about emergency medical systems (78%), medical knowledge transfer (58%), and long-term relationship formation (42%). Top challenges included rotator Spanish language proficiency (70%) lack of reciprocity (58%), and level of training and rotation length (25%). Spanish proficiency related directly to how involved rotators became in patient care (e.g., taking a history, participating in rounds) but was not completely prohibitive, as a majority of physicians interviewed felt comfortable speaking in English. Lack of reciprocity refers to the difficulty of sending host physicians abroad as well as failed attempts at building long-lasting relationships with foreign institutions. Lastly, 25% preferred rotators to stay for at least 1 month and rotate in the last year of EM residency. This latter preference increased knowledge transfer from rotator to host. Conclusions Our research identified benefits and challenges of IHEs in Emergency Medicine from the perspective of physician hosts in several hospitals in South America. Our results suggest that IHEs function best when EM residents rotate later in residency training and when relationships are maintained and deepened among those involved including host physicians, rotators, and institutions. This leads to future rotators, project collaboration, research, and publications which not only benefit individuals involved but also the wider field of Emergency Medicine. PMID:25635188

Perspectives of South American physicians hosting foreign rotators in emergency medicine.

PubMed

O'Donnell, Steve; Adler, David H; Inboriboon, Pholaphat Charles; Alvarado, Hermenegildo; Acosta, Raul; Godoy-Monzon, Daniel

2014-01-01

Emergency Medicine (EM) is increasingly becoming an international field. The number of fellowships in International EM in the USA is growing along with opportunities to complete international health electives (IHEs) during residency training. The impact on host institutions, however, has not been adequately investigated. The objective of this study is to assess the experience of several South American hospitals hosting foreign EM residents completing IHEs. Anonymous, semi-structured one-on-one interviews were conducted with physicians working in Emergency Departments in three hospitals in Lima, Peru and one hospital in Buenos Aires, Argentina. All participants reported previously working with EM foreign rotators. Interviews were analyzed qualitatively and coded for common themes. Three department chairs, six residents, and 15 attending physicians were interviewed (total = 24). After qualitative analysis of interviews, two broad theme categories emerged: Benefits and Challenges. Most commonly reported benefits were knowledge sharing about emergency medical systems (78%), medical knowledge transfer (58%), and long-term relationship formation (42%). Top challenges included rotator Spanish language proficiency (70%) lack of reciprocity (58%), and level of training and rotation length (25%). Spanish proficiency related directly to how involved rotators became in patient care (e.g., taking a history, participating in rounds) but was not completely prohibitive, as a majority of physicians interviewed felt comfortable speaking in English. Lack of reciprocity refers to the difficulty of sending host physicians abroad as well as failed attempts at building long-lasting relationships with foreign institutions. Lastly, 25% preferred rotators to stay for at least 1 month and rotate in the last year of EM residency. This latter preference increased knowledge transfer from rotator to host. Our research identified benefits and challenges of IHEs in Emergency Medicine from the perspective of physician hosts in several hospitals in South America. Our results suggest that IHEs function best when EM residents rotate later in residency training and when relationships are maintained and deepened among those involved including host physicians, rotators, and institutions. This leads to future rotators, project collaboration, research, and publications which not only benefit individuals involved but also the wider field of Emergency Medicine.

Reef fishes can recognize bleached habitat during settlement: sea anemone bleaching alters anemonefish host selection

PubMed Central

Scott, Anna; Dixson, Danielle L.

2016-01-01

Understanding how bleaching impacts the settlement of symbiotic habitat specialists and whether there is flexibility in settlement choices with regard to habitat quality is essential given our changing climate. We used five anemonefishes (Amphiprion clarkii, Amphiprion latezonatus, Amphiprion ocellaris, Amphiprion percula and Premnas biaculeatus) and three host sea anemones (Entacmaea quadricolor, Heteractis crispa and Heteractis magnifica) in paired-choice flume experiments to determine whether habitat naive juveniles have the olfactory capabilities to distinguish between unbleached and bleached hosts, and how this may affect settlement decisions. All anemonefishes were able to distinguish between bleached and unbleached hosts, and responded only to chemical cues from species-specific host anemones irrespective of health status, indicating a lack of flexibility in host use. While bleached hosts were selected as habitat, this occurred only when unbleached options were unavailable, with the exception of A. latezonatus, which showed strong preferences for H. crispa regardless of health. This study highlights the potential deleterious indirect impacts of declining habitat quality during larval settlement in habitat specialists, which could be important in the field, given that bleaching events are becoming increasingly common. PMID:27226472

Reef fishes can recognize bleached habitat during settlement: sea anemone bleaching alters anemonefish host selection.

PubMed

Scott, Anna; Dixson, Danielle L

2016-05-25

Understanding how bleaching impacts the settlement of symbiotic habitat specialists and whether there is flexibility in settlement choices with regard to habitat quality is essential given our changing climate. We used five anemonefishes (Amphiprion clarkii, Amphiprion latezonatus, Amphiprion ocellaris, Amphiprion percula and Premnas biaculeatus) and three host sea anemones (Entacmaea quadricolor, Heteractis crispa and Heteractis magnifica) in paired-choice flume experiments to determine whether habitat naive juveniles have the olfactory capabilities to distinguish between unbleached and bleached hosts, and how this may affect settlement decisions. All anemonefishes were able to distinguish between bleached and unbleached hosts, and responded only to chemical cues from species-specific host anemones irrespective of health status, indicating a lack of flexibility in host use. While bleached hosts were selected as habitat, this occurred only when unbleached options were unavailable, with the exception of A. latezonatus, which showed strong preferences for H. crispa regardless of health. This study highlights the potential deleterious indirect impacts of declining habitat quality during larval settlement in habitat specialists, which could be important in the field, given that bleaching events are becoming increasingly common. © 2016 The Author(s).

Long-Duration Gamma-Ray Burst Host Galaxies in Emission and Absorption

NASA Astrophysics Data System (ADS)

Perley, Daniel A.; Niino, Yuu; Tanvir, Nial R.; Vergani, Susanna D.; Fynbo, Johan P. U.

2016-12-01

The galaxy population hosting long-duration GRBs provides a means to constrain the progenitor and an opportunity to use these violent explosions to characterize the nature of the high-redshift universe. Studies of GRB host galaxies in emission reveal a population of star-forming galaxies with great diversity, spanning a wide range of masses, metallicities, and redshifts. However, as a population GRB hosts are significantly less massive and poorer in metals than the hosts of other core-collapse transients, suggesting that GRB production is only efficient at metallicities significantly below Solar. GRBs may also prefer compact galaxies, and dense and/or central regions of galaxies, more than other types of core-collapse explosion. Meanwhile, studies of hosts in absorption against the luminous GRB optical afterglow provide a unique means of unveiling properties of the ISM in even the faintest and most distant galaxies; these observations are helping to constrain the chemical evolution of galaxies and the properties of interstellar dust out to very high redshifts. New ground- and space-based instrumentation, and the accumulation of larger and more carefully-selected samples, are continually enhancing our view of the GRB host population.

The host preference and impact of Argulus japonicus ectoparasite on cyprinids in Central Java, Indonesia

NASA Astrophysics Data System (ADS)

Kismiyati; Wulansari, P. D.; Dewi, N. N.

2018-04-01

The most widely cultivated freshwater fish are from Familia Cyprinidae, among others goldfish (Carassius auratus), koi (Cyprinus carpio) and comet goldfish (Carassius auratus auratus). One of the constraints of freshwater fish cultivation is ectoparasite infestation Argulus japonicus. Financial losses have been experienced by some farmers, caused by these ectoparasitic infestaions. This study was aimed to determine the impact of ectoparasite Argulus japonicus infestation on host (freshwater ornamental fish from Familia Cyprinidae), in order to find a preventive solution to treatment on the host. The results showed that prevalence of infested fish by Argulus japonicus were 57 % goldfish, 31 % comet fish and 65 % koi. Changes of histopathology on host were congestion, baoning degeneration, epithelium erosion and inflammatory cell infiltration. The image of infected leukocytes infested by Argulus japonicus were 8.5 % of lymphocytes, 4.7 % neurophils, 3.9 % monocytes, 1.45 % eosinophils and 0,17% basophils.

Evolution of active host-attraction strategies in the freshwater mussel tribe Lampsilini (Bivalvia: Unionidae).

PubMed

Zanatta, David T; Murphy, Robert W

2006-10-01

Most freshwater mussels (Bivalvia: Unionoida) require a host, usually a fish, to complete their life cycle. Most species of mussels show adaptations that increase the chances of glochidia larvae contacting a host. We investigated the evolutionary relationships of the freshwater mussel tribe Lampsilini including 49 of the approximately 100 extant species including 21 of the 24 recognized genera. Mitochondrial DNA sequence data (COI, 16S, and ND1) were used to create a molecular phylogeny for these species. Parsimony and Bayesian likelihood topologies revealed that the use of an active lure arose early in the evolution of the Lampsiline mussels. The mantle flap lure appears to have been the first to evolve with other lure types being derived from this condition. Apparently, lures were lost independently in several clades. Hypotheses are discussed as to how some of these lure strategies may have evolved in response to host fish prey preferences.

How Does the Shape of the Stellar Spectrum Affect the Raman Scattering Features in the Albedo of Exoplanets?

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

Oklopčić, Antonija; Hirata, Christopher M.; Heng, Kevin, E-mail: oklopcic@astro.caltech.edu

The diagnostic potential of the spectral signatures of Raman scattering, imprinted in planetary albedo spectra at short optical wavelengths, has been demonstrated in research on planets in the solar system, and has recently been proposed as a probe of exoplanet atmospheres, complementary to albedo studies at longer wavelengths. Spectral features caused by Raman scattering offer insight into the properties of planetary atmospheres, such as the atmospheric depth, composition, and temperature, as well as the possibility of detecting and spectroscopically identifying spectrally inactive species, such as H{sub 2} and N{sub 2}, in the visible wavelength range. Raman albedo features, however, dependmore » on both the properties of the atmosphere and the shape of the incident stellar spectrum. Identical planetary atmospheres can produce very different albedo spectra depending on the spectral properties of the host star. Here we present a set of geometric albedo spectra calculated for atmospheres with H{sub 2}/He, N{sub 2}, and CO{sub 2} composition, irradiated by different stellar types ranging from late A to late K stars. Prominent albedo features caused by Raman scattering appear at different wavelengths for different types of host stars. We investigate how absorption due to the alkali elements sodium and potassium may affect the intensity of Raman features, and we discuss the preferred strategies for detecting Raman features in future observations.« less

Choices and consequences of oviposition by a pollinating seed predator, Hadena ectypa (Noctuidae), on its host plant, Silene stellata (Caryophyllaceae).

PubMed

Kula, Abigail A R; Dudash, Michele R; Fenster, Charles B

2013-06-01

Pollinating seed predators are models for the study of mutualisms. These insects have dual effects on host-plant fitness, through pollination as adults and flower and fruit predation as larvae. A rarely examined question is whether pollinating seed-predator oviposition choices are influenced by plant floral and size traits and the potential consequences of oviposition for host-plant reproduction. • We quantified oviposition by a pollinating seed predator, Hadena ectypa, on its host, Silene stellata, to determine if oviposition was associated with specific plant traits and whether oviposition was significantly correlated with fruit initiation or flower and fruit predation over three years. We also quantified whether stigmatic pollen loads of flowers visited by Hadena that both fed on nectar and oviposited were greater than when Hadena only fed on nectar. • Hadena had significant preference for plants having flowers with long corolla tubes in all three years. Moth oviposition was correlated with other traits only in some years. Oviposition did not increase stigmatic pollen loads. We observed significant positive relationships between both oviposition and fruit initiation and oviposition and flower/fruit predation. • Hadena ectypa oviposition choices were based consistently on floral tube length differences among individuals, and the consequences of oviposition include both fruit initiation (due to pollination while feeding on nectar prior to oviposition) and larval flower/fruit predation. The positive association between oviposition and fruit initiation may explain the long-term maintenance of facultative pollinating seed-predator interactions.

Behavioral assays for evaluating host preferences of Euwallacea nr. fornicatus (Coleoptera: Curculionidae: Scolytinae).

USDA-ARS?s Scientific Manuscript database

In 2010, the exotic ambrosia beetle, Euwallacea nr. fornicatus Eichhoff (Coleoptera: Curculionidae: Scolytinae) was first discovered in Florida avocado groves. Introduction of its symbiotic Fusarium spp. fungi into galleries in the xylem tissue results in Fusarium-dieback disease. Unlike most ambros...

Insights to host discrimination and host acceptance behaviour in a parasitoid (Diptera: Asilidae): implications for fitness.

PubMed

Crespo, José E; Castelo, Marcela K

2009-11-01

The robber fly Mallophora ruficauda is one of the principal pests of apiculture in the Pampas region of Argentina. As adults they prey on honey bees and other insects, while as larvae they are solitary ectoparasitoids of third instar scarab beetle larvae. Females of M. ruficauda lay eggs away from the host in tall grasses. After being dispersed by the wind, larvae drop to the ground, where they dig in search of their hosts. It is known that second instar larvae of M. ruficauda exhibit active host searching behaviour towards its preferred host, third instar larva of Cyclocephala signaticollis. Although the means by which host location occurs has been studied and since superparasitism is a frequent scenario in the field, no information about host discrimination and host acceptance is available. We carried out studies in the field and behavioural experiments in the laboratory to determine if M. ruficauda is capable of quality host discrimination. We also studied if this parasitoid is capable of conspecific detection in order to avoid superparasitism. Finally, we analyzed the conditions under which superparasitism occurs in the field. We report here that the second instar larva of M. ruficauda is able to discriminate the parasitism status of the host by means of chemical cues, but is not capable of detecting conspecifics prior to attacking a host. We also found that the host cannot detect the presence of the parasitoid by means of chemical cues, so that no counter-defense against parasitism occurs. Furthermore, we determined that superparasitism occurs on the heavier hosts, i.e. those with more abundant resources which could harbor several parasitoid individuals. Finally, we discuss the possible implications of larval host location and host discrimination decisions on the fitness of this parasitoid.

Revisiting Host Preference in the Mycobacterium tuberculosis Complex: Experimental Infection Shows M. tuberculosis H37Rv to Be Avirulent in Cattle

PubMed Central

Whelan, Adam O.; Coad, Michael; Cockle, Paul J.; Hewinson, Glyn; Vordermeier, Martin; Gordon, Stephen V.

2010-01-01

Experiments in the late 19th century sought to define the host specificity of the causative agents of tuberculosis in mammals. Mycobacterium tuberculosis, the human tubercle bacillus, was independently shown by Smith, Koch, and von Behring to be avirulent in cattle. This finding was erroneously used by Koch to argue the converse, namely that Mycobacterium bovis, the agent of bovine tuberculosis, was avirulent for man, a view that was subsequently discredited. However, reports in the literature of M. tuberculosis isolation from cattle with tuberculoid lesions suggests that the virulence of M. tuberculosis for cattle needs to be readdressed. We used an experimental bovine infection model to test the virulence of well-characterized strains of M. tuberculosis and M. bovis in cattle, choosing the genome-sequenced strains M. tuberculosis H37Rv and M. bovis 2122/97. Cattle were infected with approximately 106 CFU of M. tuberculosis H37Rv or M. bovis 2122/97, and sacrificed 17 weeks post-infection. IFN-γ and tuberculin skin tests indicated that both M. bovis 2122 and M. tuberculosis H37Rv were equally infective and triggered strong cell-mediated immune responses, albeit with some indication of differential antigen-specific responses. Postmortem examination revealed that while M. bovis 2122/97–infected animals all showed clear pathology indicative of bovine tuberculosis, the M. tuberculosis–infected animals showed no pathology. Culturing of infected tissues revealed that M. tuberculosis was able to persist in the majority of animals, albeit at relatively low bacillary loads. In revisiting the early work on host preference across the M. tuberculosis complex, we have shown M. tuberculosis H37Rv is avirulent for cattle, and propose that the immune status of the animal, or genotype of the infecting bacillus, may have significant bearing on the virulence of a strain for cattle. This work will serve as a baseline for future studies into the genetic basis of host preference, and in particular the molecular basis of virulence in M. bovis. PMID:20049086

Eco-evolutionary spatial dynamics in the Glanville fritillary butterfly

PubMed Central

Hanski, Ilkka A.

2011-01-01

Demographic population dynamics, gene flow, and local adaptation may influence each other and lead to coupling of ecological and evolutionary dynamics, especially in species inhabiting fragmented heterogeneous environments. Here, I review long-term research on eco-evolutionary spatial dynamics in the Glanville fritillary butterfly inhabiting a large network of approximately 4,000 meadows in Finland. The metapopulation persists in a balance between frequent local extinctions and recolonizations. The genetic spatial structure as defined by neutral markers is much more coarse-grained than the demographic spatial structure determined by the fragmented habitat, yet small-scale spatial structure has important consequences for the dynamics. I discuss three examples of eco-evolutionary spatial dynamics. (i) Extinction-colonization metapopulation dynamics influence allele frequency changes in the phosphoglucose isomerase (Pgi) gene, which leads to strong associations between genetic variation in Pgi and dispersal, recolonization, and local population dynamics. (ii) Inbreeding in local populations increases their risk for extinction, whereas reciprocal effects between inbreeding, population size, and emigration represent likely eco-evolutionary feedbacks. (iii) Genetically determined female oviposition preference for two host plant species exhibits a cline paralleling a gradient in host plant relative abundances, and host plant preference of dispersing females in relation to the host plant composition of habitat patches influences immigration (gene flow) and recolonization (founder events). Eco-evolutionary spatial dynamics in heterogeneous environments may not lead to directional evolutionary changes unless the environment itself changes, but eco-evolutionary dynamics may contribute to the maintenance of genetic variation attributable to fluctuating selection in space and time. PMID:21788506

No evidence for host specialization or host-race formation in the European bitterling (Rhodeus amarus), a fish that parasitizes freshwater mussels.

PubMed

Reichard, M; Bryja, J; Polačik, M; Smith, C

2011-09-01

Coevolutionary relationships between parasites and hosts can elevate the rate of evolutionary changes owing to reciprocal adaptations between coevolving partners. Such relationships can result in the evolution of host specificity. Recent methodological advances have permitted the recognition of cryptic lineages, with important consequences for our understanding of biological diversity. We used the European bitterling (Rhodeus amarus), a freshwater fish that parasitizes unionid mussels, to investigate host specialization across regions of recent and ancient sympatry between coevolving partners. We combined genetic data (12 microsatellite and 2 mitochondrial markers) from five populations with experimental data for possible mechanisms of host species recognition (imprinting and conditioning). We found no strong evidence for the existence of cryptic lineages in R. amarus, though a small proportion of variation among individuals in an area of recent bitterling-mussel association was statistically significant in explaining host specificity. No other measures supported the existence of host-specific lineages. Behavioural data revealed a weak effect of conditioning that biased behavioural preferences towards specific host species. Host imprinting had no effect on oviposition behaviour. Overall, we established that populations of R. amarus show limited potential for specialization, manifested as weak effects of host conditioning and genetic within-population structure. Rhodeus amarus is the only species of mussel-parasitizing fish in Europe, which contrasts with the species-rich communities of bitterling in eastern Asia where several host-specific bitterling occur. We discuss costs and constraints on the evolution of host-specific lineages in our study system and more generally. © 2011 Blackwell Publishing Ltd.

Genetic differences among Anopheles vestitipennis subpopulations collected using different methods in Chiapas state, southern México.

PubMed

Arredondo-Jiménez, J I; Gimnig, J; Rodríguez, M H; Washino, R K

1996-09-01

Biting activity and population genetic studies of the malaria vector Anopheles vestitipennis were conducted in southern México. Three subpopulations were collected from 2 villages; 2 subpopulations were from the same village, one on human bait and one with an animal-baited trap; the third was collected from a cattle corral in the 2nd village (280 km away SSE). The anthropophilic subpopulation had steady activity with 61% of bites occurring before midnight, significantly different from those of the 2 zoophilic subpopulations, which had 78-82% of bites before midnight and 2 biting peaks, one at 1900-2100 h and the other at 0400-0500 h. Isozyme analysis (13 enzymes) of these subpopulations indicated that differences between the 2 sympatric subpopulations (D = 0.07), collected using 2 different methods, were greater than that between the 2 allopatric ones (D = 0.03). These studies suggest the existence of 2 genetically different subpopulations of An. vestitipennis with specific host preferences.

Host status of grapefruit and Valencia oranges for Anastrepha serpentina and Anastrepha ludens (Diptera: Tephritidae).

PubMed

Mangan, Robert L; Thomas, Donald B; Moreno, Aleena M Tarshis

2011-04-01

Anastrepha serpentina (Wiedemann) (Diptera: Tephritidae) is sporadically captured in the Rio Grande Valley of Texas. Although its preferred hosts are in the Sapotaceae family, several varieties of Citrus, including grapefruit and oranges are listed as alternate hosts. Although Mexican fruit fly, Anastrepha ludens (Loew), is known to be a major pest of Citrus, doubt exists as to the status of Citrus as a breeding host for A. serpentina. To evaluate the host status of commercial Citrus for A. serpentina we compared oviposition and development with that of A. ludens under laboratory conditions with 'Rio Red' grapefruit (Citrus paradisi MacFayden) and 'Valencia' oranges [Citrus sinensis (L.) Osbeck] in different stages of maturity. Both fly species oviposited in early season fruit in which the eggs and larvae died in the fruit albedo. Survival of either species to the adult stage occurred in later season grapefruit. In oranges, no A. serpentina larvae survived compared with 150 A. ludens surviving to adults. Survival on both Citrus species was much lower for A. serpentina, only approximately 5% of eggs eclosed into larvae in grapefruit compared with approximatley 50% for A. ludens. In oranges approximately 16% of A. serpentina eggs eclosed compared with approximately 76% for A. ludens. In grapefruit, only one fourth as many A. serpentina larvae survived to the adult stage compared with A. ludens. Additional experiments were performed in a greenhouse on small, caged trees of la coma (Sideroxylon celastrinum H.B.K.), a Texas species of Sapotaceae. The A. serpentina females readily oviposited into these berries and normal adults emerged. The present low incidence of the adults, coupled with the high mortality during development of the larvae, suggests that Texas citrus is unlikely to support a breeding population of A. serpentina.

SNP-based differentiation of Phytophthora infestans clonal lineages using locked nucleic acid probes and high resolution melt analysis

USDA-ARS?s Scientific Manuscript database

Phytophthora infestans, the cause of the devastating late blight disease of potato and tomato, exhibits a clonal reproductive lifestyle in North America. Phenotypes such as fungicide sensitivity and host preference are conserved among individuals within clonal lineages, while substantial phenotypic ...

Host plant oviposition preference of Ceratapion basicorne (Coleoptera:Apionidae), a potential biological control agent of yellow starthistle

USDA-ARS?s Scientific Manuscript database

Ceratapion basicorne (Coleoptera: Apionidae) is a weevil native to Europe and western Asia that is being evaluated as a prospective classical biological control agent of Centaurea solstitialis (yellow starthistle) in the United States. Choice oviposition experiments were conducted under laboratory ...

Attraction, oviposition preferences, and olfactory responses of corn-infesting Ulidiidae (Diptera) to various host-based substrates

USDA-ARS?s Scientific Manuscript database

Fresh market sweet corn produced in Florida is threatened by larval damage by Euxesta stigmatias Loew, E. eluta Loew, and Chaetopsis massyla Walker (Diptera: Ulidiidae) that renders ears unmarketable. No standard lure exists for monitoring these pests. Oviposition and attraction bioassays were desig...

Arsenal of plant cell wall degrading enzymes reflects host preference among plant pathogenic fungi

USDA-ARS?s Scientific Manuscript database

Discovery and development of novel plant cell wall degrading enzymes is a key step towards more efficient depolymerization of polysaccharides to fermentable sugars for production of liquid transportation biofuels and other bioproducts. The industrial fungus Trichoderma reesei is known to be highly c...

Male sexual behavior and pheromone emission is enhanced by exposure to guava fruit volatiles in Anastrepha fraterculus

USDA-ARS?s Scientific Manuscript database

Host plant chemicals can influence sex pheromone communication of tephritid fruit flies, and affect strategies optimizing mating and reproduction. Previous studies suggest that females of the South American fruit fly, Anastrepha fraterculus, prefer to mate with laboratory males previously exposed to...

Demonstration using field collections that Argentina fall armyworm populations exhibit strain-specific host plant preferences

USDA-ARS?s Scientific Manuscript database

Spodoptera frugiperda, the fall armyworm, is a major economic pest throughout the Western Hemisphere of corn (maize), cotton, sorghum, and a variety of agricultural grasses and vegetable crops. Studies in the United States, the Caribbean, and Brazil demonstrated the existence of two subpopulations ...

Biology and host preferences of Cryptorhynchus melastomae (Coleoptera: Curculionidae), a possible biocontrol agent for Miconia calvescens (Melastomataceae) in Hawaii

Treesearch

E. Reichert; M.T. Johnson; E. Chacon; R.S. Anderson; T.A. Wheeler

2010-01-01

The introduced plant Miconia calvescens (Melastomataceae) poses a grave threat to Hawaii's native ecosystems and biodiversity. One potential candidate for classical biological control is Cryptorhynchus melastomae (Coleoptera: Curculionidae: Cryptorhynchinae), a stem-boring weevil from Central and South America. This weevil...

Determinants of the geographic distribution of Puumala virus and Lyme borreliosis infections in Belgium

PubMed Central

Linard, Catherine; Lamarque, Pénélope; Heyman, Paul; Ducoffre, Geneviève; Luyasu, Victor; Tersago, Katrien; Vanwambeke, Sophie O; Lambin, Eric F

2007-01-01

Background Vector-borne and zoonotic diseases generally display clear spatial patterns due to different space-dependent factors. Land cover and land use influence disease transmission by controlling both the spatial distribution of vectors or hosts, and the probability of contact with susceptible human populations. The objective of this study was to combine environmental and socio-economic factors to explain the spatial distribution of two emerging human diseases in Belgium, Puumala virus (PUUV) and Lyme borreliosis. Municipalities were taken as units of analysis. Results Negative binomial regressions including a correction for spatial endogeneity show that the spatial distribution of PUUV and Lyme borreliosis infections are associated with a combination of factors linked to the vector and host populations, to human behaviours, and to landscape attributes. Both diseases are associated with the presence of forests, which are the preferred habitat for vector or host populations. The PUUV infection risk is higher in remote forest areas, where the level of urbanisation is low, and among low-income populations. The Lyme borreliosis transmission risk is higher in mixed landscapes with forests and spatially dispersed houses, mostly in wealthy peri-urban areas. The spatial dependence resulting from a combination of endogenous and exogenous processes could be accounted for in the model on PUUV but not for Lyme borreliosis. Conclusion A large part of the spatial variation in disease risk can be explained by environmental and socio-economic factors. The two diseases not only are most prevalent in different regions but also affect different groups of people. Combining these two criteria may increase the efficiency of information campaigns through appropriate targeting. PMID:17474974

Site preferences of actinide cations in [NZP] compounds

NASA Astrophysics Data System (ADS)

Hawkins, H. T.; Spearing, D. R.; Smith, D. M.; Hampel, F. G.; Veirs, D. K.; Scheetz, B. E.

2000-07-01

Compounds adopting the sodium dizirconium tris(phosphate) (NaZr2(PO4)3) structure type belong to the [NZP] structural family of compounds. [NZP] compounds possess desirable properties that would permit their application as hosts for the actinides. These properties include compositional flexibility (i.e., three structural sites that can accommodate a variety of different cations), high thermal stability, negligible thermal expansion, and resistance to radiation damage. Experimental data indicate that [NZP] compounds resist dissolution and release of constituents over a wide range of experimental conditions. Moreover, [NZP] compounds may be synthesized by both conventional and novel methods and may be heat treated or sintered at modest temperatures (800 °C-1350 °C) in open or restricted systems.

Oviposition preference of cabbage white butterflies in the framework of costs and benefits of interspecific herbivore associations

PubMed Central

Shiojiri, Kaori; Sabelis, Maurice; Takabayashi, Junji

2015-01-01

When deciding where to oviposit, herbivorous insects consider: (i) the plant’s value as a food source, (ii) the risks of competing with con- and heterospecific herbivores, and (iii) the risks of parasitism and predation on the host plant. The presence of con- and/or heterospecific competitors would further affect the oviposition preference, because the preceding herbivores induce direct/indirect defences in plants against forthcoming herbivores, and thereby alter oviposition decisions. In previous studies, the abovementioned factors have not been studied in an integrative manner. We performed here a case study of this by assessing the oviposition preferences of a small white butterfly, Pieris rapae, for plants occupied by combinations of conspecific larvae, heterospecific larvae (Plutella xylostella), specialist parasitoids of Pi. rapae (Cotesia glomerata) and generalist predators (ants). We previously reported that the females showed equal preference for Pl. xylostella-infested and uninfested plants. Here, we showed that Pi. rapae females preferred uninfested plants to conspecific-infested ones, and Pl. xylostella-infested plants to Pi. rapae-infested ones. We discuss these oviposition preferences of Pi. rapae females in the framework of costs and benefits of interspecific herbivore associations from the above point of view. PMID:27019738

Evidence for host plant preference by Iphiseiodes quadripilis (Acari: Phytoseiidae) on Citrus.

PubMed

Villanueva, Raul T; Childers, Carl C

2006-01-01

In this study, we present field and laboratory evidence on the preference of Iphiseiodes quadripilis (Banks) for grapefruit (Citrus paradisi Macfadyen) leaves compared with sweet orange (Citrus sinensis (L.) Osbeck) leaves. This preference was confirmed in four orchards whether leaf samples were taken from either border trees of contiguous grapefruit or sweet orange or interior row trees with both citrus species in adjacent rows. Iphiseiodes quadripilis was most abundant in grapefruit trees in spite of the greater abundance of the Texas citrus mite, Eutetranychus banksi (McGregor) (Acari: Tetranychidae) in sweet orange trees. Similar preference responses were observed in laboratory tests using a Y-tube olfactometer whether I. quadripilis were collected from sweet orange or grapefruit. Iphiseiodes quadripilis collected from grapefruit trees showed significant preference for grapefruit over sweet orange leaves in contact choice tests using an arena of alternating leaf strips (12 mm long x 2 mm wide) of sweet orange and grapefruit. However, I. quadripilis collected from sweet orange trees did not show preference for either grapefruit or sweet orange leaves. Based on these results, grapefruit leaves foster some unknown factor or factors that retain I. quadripilis in greater numbers compared with sweet orange leaves.

High-throughput olfactory conditioning and memory retention test show variation in Nasonia parasitic wasps

PubMed Central

Hoedjes, K M; Steidle, J L M; Werren, J H; Vet, L E M; Smid, H M

2012-01-01

Most of our knowledge on learning and memory formation results from extensive studies on a small number of animal species. Although features and cellular pathways of learning and memory are highly similar in this diverse group of species, there are also subtle differences. Closely related species of parasitic wasps display substantial variation in memory dynamics and can be instrumental to understanding both the adaptive benefit of and mechanisms underlying this variation. Parasitic wasps of the genus Nasonia offer excellent opportunities for multidisciplinary research on this topic. Genetic and genomic resources available for Nasonia are unrivaled among parasitic wasps, providing tools for genetic dissection of mechanisms that cause differences in learning. This study presents a robust, high-throughput method for olfactory conditioning of Nasonia using a host encounter as reward. A T-maze olfactometer facilitates high-throughput memory retention testing and employs standardized odors of equal detectability, as quantified by electroantennogram recordings. Using this setup, differences in memory retention between Nasonia species were shown. In both Nasonia vitripennis and Nasonia longicornis, memory was observed up to at least 5 days after a single conditioning trial, whereas Nasonia giraulti lost its memory after 2 days. This difference in learning may be an adaptation to species-specific differences in ecological factors, for example, host preference. The high-throughput methods for conditioning and memory retention testing are essential tools to study both ultimate and proximate factors that cause variation in learning and memory formation in Nasonia and other parasitic wasp species. PMID:22804968

Analysing the oviposition behaviour of malaria mosquitoes: design considerations for improving two-choice egg count experiments.

PubMed

Okal, Michael N; Lindh, Jenny M; Torr, Steve J; Masinde, Elizabeth; Orindi, Benedict; Lindsay, Steve W; Fillinger, Ulrike

2015-06-20

Choice egg-count bioassays are a popular tool for analysing oviposition substrate preferences of gravid mosquitoes. This study aimed at improving the design of two-choice experiments for measuring oviposition substrates preferences of the malaria vector Anopheles gambiae senso lato, a mosquito that lays single eggs. In order to achieve high egg-laying success of female An. gambiae sensu stricto (s.s.) and Anopheles arabiensis mosquitoes in experiments, four factors were evaluated: (1) the time provided for mating; (2) the impact of cage size, mosquito age and female body size on insemination; (3) the peak oviposition time; and, (4) the host sources of blood meal. Choice bioassays, with one mosquito released in each cage containing two oviposition cups both with the same oviposition substrate (100 ml water), were used to measure and adjust for egg-laying characteristics of the species. Based on these characteristics an improved design for the egg-count bioassay is proposed. High oviposition rates [84%, 95% confidence interval (CI) 77-89%] were achieved when 300 male and 300 blood-fed female An. gambiae s.s. were held together in a cage for 4 days. The chances for oviposition dropped (odds ratio 0.30; 95% CI 0.14-0.66) when human host source of blood meal was substituted with a rabbit but egg numbers per female were not affected. The number of eggs laid by individual mosquitoes was overdispersed (median = 52, eggs, interquartile range 1-214) and the numbers of eggs laid differed widely between replicates, leading to a highly heterogeneous variance between groups and/or rounds of experiments. Moreover, one-third of mosquitoes laid eggs unequally in both cups with similar substrates giving the illusion of choice. Sample size estimations illustrate that it takes 165 individual mosquitoes to power bioassays sufficiently (power = 0.8, p = 0.05) to detect a 15% shift in comparative preferences of two treatments. Two-choice egg count bioassays with Anopheles are best done with a two-tier design that (1) implements a parallel series of experiments with mosquitoes given a choice of two identical substrates choices and, (2) uses a single mosquito in each test cage rather than groups of mosquitoes to assess the preference of a test or control solution. This approach, with sufficient replication, lowers the risk detecting pseudopreferences.

Successful Feeding of Amblyomma coelebs (Acari: Ixodidae) Nymphs on Humans in Brazil: Skin Reactions to Parasitism.

PubMed

Garcia, Marcos V; Matias, Jaqueline; Aguirre, AndrÉ De A R; Csordas, Barbara G; SzabÓ, Matias P J; Andreotti, Renato

2015-03-01

Identifying the tick species that successfully feed on humans would increase knowledge of the epidemiology of several tick-borne diseases. These species salivate into the host, increasing the risk of pathogen transmission. However, there is a lack of data in the literature regarding the ticks that prefer to feed on humans. Herein, we describe the successful feeding of Amblyomma coelebs Neumann nymphs on two of the authors after accidental tick bites occurred during field surveys in two preserved areas of Mato Grosso do Sul, Brazil. One of the host-parasite interactions was closely monitored, and the tick development, gross host skin alterations, and related sensations are presented. © The Author 2015. Published by Oxford University Press on behalf of Entomological Society of America.

[Localization of larvae of Neotrombicula (N) monticola (Trombiculidae) ticks on the vertebrates].

PubMed

Chirov, P A; Kharadov, A V

2007-01-01

The specific features of distribution of Neotrombicula (N) monticola Schluger et Davidov, 1967 on small mammals were studied in the Tien Shan montains (Kirghiz ridge). N. (N ) monticola was found to occur in all the places under study. Nine species of mammals (pigmy white-toothed shrew, dwarf hamster, tamarisk gerbil, Turkestan rat, long-tailed mouse, Tien Shan, Kirghiz, and silver voles, and wood mouse) were established to be feeders of larvae of the ticks. N. (N) monticola larvae were detected in three topographic zones and seven portions of the body of vertebral hosts. The inner auricle is the major site of tick attachment to the host. Preference of N. (N) monticola in selecting the host is likely to be based on the morphophysiological features of partners.

An illustrated key to Neotropical species of the genus Meteorus Haliday (Hymenoptera, Braconidae, Euphorinae).

PubMed

Aguirre, Helmuth; de Almeida, Luis Felipe; Shaw, Scott Richard; Sarmiento, Carlos E

2015-01-01

A comprehensive key for 75 species of Meteorus distributed across 15 Neotropical countries is presented. Eleven new species from Bolivia, Costa Rica and Ecuador are described: Meteorusalbistigma, Meteoruscarolae, Meteoruseurysaccavorus, Meteorusfallacavus, Meteorusflavistigma, Meteorushaimowitzi, Meteorusmagnoculus, Meteorusmartinezi, Meteorusmicrocavus, Meteorusnoctuivorus and Meteorusorion. Expanded range distributions are recorded for Meteorusandreae, Meteorusfarallonensis, Meteorusguineverae, Meteorusjerodi, Meteoruskraussi, Meteoruspapiliovorus and Meteorusquimbayensis. The host of Meteorusjerodi is reported for the first time: a noctuid larva feeding on Asteraceae. Meteoruspapiliovorus is recorded attacking Papilionidae larvae in Ecuador, therefore displaying a similar host family preference as formerly documented from Costa Rica and Colombia.

Comparative morphology of the mouthparts of the megadiverse South African monkey beetles (Scarabaeidae: Hopliini): feeding adaptations and guild structure

PubMed Central

Hansal, Teresa; Krenn, Harald W.; Colville, Jonathan F.

2016-01-01

Although anthophilous Coleoptera are regarded to be unspecialised flower-visiting insects, monkey beetles (Scarabaeidae: Hopliini) represent one of the most important groups of pollinating insects in South Africa’s floristic hotspot of the Greater Cape Region. South African monkey beetles are known to feed on floral tissue; however, some species seem to specialise on pollen and/or nectar. The present study examined the mouthpart morphology and gut content of various hopliine species to draw conclusions on their feeding preferences. According to the specialisations of their mouthparts, the investigated species were classified into different feeding groups. Adaptations to pollen-feeding included a well-developed, toothed molar and a lobe-like, setose lacinia mobilis on the mandible as well as curled hairs or sclerotized teeth on the galea of the maxillae. Furthermore, elongated mouthparts were interpreted as adaptations for nectar feeding. Floral- and folial-tissue feeding species showed sclerotized teeth on the maxilla, but the lacinia was mostly found to be reduced to a sclerotized ledge. While species could clearly be identified as floral or folial tissue feeding, several species showed intermediate traits suggesting both pollen and nectar feeding adaptations. Mismatches found between mouthpart morphology and previously reported flower visiting behaviours across different genera and species requires alternative explanations, not necessarily associated with feeding preferences. Although detailed examinations of the mouthparts allowed conclusions about the feeding preference and flower-visiting behaviour, additional morphological and behavioural investigations, combined with greater taxon sampling and phylogenetic data, are still necessary to fully understand hopliine host plant relationships, related to monkey beetle diversity. PMID:26819850

Host-pathogen interactions in a varying environment: temperature, behavioural fever and fitness.

PubMed Central

Elliot, Sam L; Blanford, Simon; Thomas, Matthew B

2002-01-01

We demonstrate how variable temperatures, mediated by host thermoregulation and behavioural fever, critically affect the interaction between a host (the desert locust, Schistocerca gregaria) and a pathogen (the fungus Metarhizium anisopliae var. acridum). By means of behavioural thermoregulation, infected locusts can raise their body temperatures to fever levels. The adaptive value of this behaviour was examined using three thermal regimes wherein maximum body temperatures achievable were: (i) below, or (ii) at normally preferred temperatures, or were (iii) unrestricted, allowing heightened fever temperatures. All infected locusts ultimately succumbed to disease, with median survival times of 8, 15 and 21 days post-infection, respectively. Crucially, only those locusts able to fever produced viable offspring. This represents, to our knowledge, the first demonstration of the adaptive value of behavioural fever following infection with a naturally occurring pathogen. By contrast, although normal host thermoregulation moderately reduced pathogen reproduction (by 35%), there was no additional negative effect of fever, resulting in an asymmetry in the fitness consequences of fever for the host and the pathogen. The dependency of the host-pathogen interaction upon external abiotic conditions has implications for how virulence and resistance are treated both theoretically and in the management of pests and diseases. PMID:12184830

The potential of host plants for biological control of Tuta absoluta by the predator Dicyphus errans.

PubMed

Ingegno, B L; Candian, V; Psomadelis, I; Bodino, N; Tavella, L

2017-06-01

Dicyphus errans (Wolff) has been shown to be a suitable biocontrol agent for Tuta absoluta (Meyrick). This generalist predator shares various host plants with the exotic pest, and these interactions could be exploited to enhance pest control. Therefore, host preference, survival rate and development times of the predator and prey were investigated on crop and non-crop plant species. Among the tested plants, the favourite hosts were Solanum species for T. absoluta, and herb Robert, European black nightshade, courgette and tomato for D. errans. Tuta absoluta accepted the same plant species as hosts for oviposition, but it never developed on herb Robert and courgette in all the experiments. Based on our results, we would suggest the use of courgette and herb Robert in consociation with tomato and as a companion plant, respectively, which may keep pest densities below the economic threshold. Moreover, the omnivorous and widespread D. errans could be a key predator of this exotic pest, allowing a high encounter probability on several cultivated and non-cultivated plant species.

Monogenean parasites from fishes of the Vaal Dam, Gauteng Province, South Africa. I. Winter survey versus summer survey comparison from Labeo capensis (Smith, 1841) and Labeo umbratus (Smith, 1841) hosts.

PubMed

Crafford, Dionne; Luus-Powell, Wilmien; Avenant-Oldewage, Annemariè

2014-03-01

Indigenous South African Labeo spp. show promise with regard to development of semi-intensive aquaculture, yet little research on their monogenean fauna has been conducted. Ecological aspects of monogenean fauna of the moggel Labeo umbratus (Smith 1841) and the Orange River mudfish Labeo capensis (Smith 1841), as recorded during both winter and summer sampling surveys, are reported here. Fish were collected using gill nets, euthanized and gills removed and examined to both quantify parasite numbers and distribution on the gills. Results obtained support the hypothesis that gill site preference is not due to active choice for a particular attachment site, but rather a result of water flow over gills during respiration in conjunction with fish behaviour and habitat use. Interaction between individual elements investigated (temperature effects, parasite population dynamics and host population dynamics) may be largely responsible for seasonal differences in infection statistics of monogenean parasites. Such interactions should be investigated in future large scale ecological studies, in combination with experimental studies, to further elucidate these effects.

The Role of Symbiont Genetic Distance and Potential Adaptability in Host Preference Towards Pseudonocardia Symbionts in Acromyrmex Leaf-Cutting Ants

PubMed Central

Poulsen, Michael; Maynard, Janielle; Roland, Damien L; Currie, Cameron R

2011-01-01

Fungus-growing ants display symbiont preference in behavioral assays, both towards the fungus they cultivate for food and Actinobacteria they maintain on their cuticle for antibiotic production against parasites. These Actinobacteria, genus Pseudonocardia Henssen (Pseudonocardiacea: Actinomycetales), help defend the ants' fungal mutualist from specialized parasites. In Acromyrmex Mayr (Hymenoptera: Formicidae) leaf-cutting ants, individual colonies maintain either a single or a few strains of Pseudonocardia, and the symbiont is primarily vertically transmitted between generations by colony-founding queens. A recent report found that Acromyrmex workers are able to differentiate between their native Pseudonocardia strain and non-native strains isolated from sympatric or allopatric Acromyrmex species, and show preference for their native strain. Here we explore worker preference when presented with two non-native strains, elucidating the role of genetic distance on preference between strains and Pseudonocardia origin. Our findings suggest that ants tend to prefer bacteria more closely related to their native bacterium and that genetic similarity is probably more important than whether symbionts are ant-associated or free-living. Preliminary findings suggest that when continued exposure to a novel Pseudonocardia strain occurs, ant symbiont preference is potentially adaptable, with colonies apparently being able to alter symbiont preference over time. These findings are discussed in relation to the role of adaptive recognition, potential ecological flexibility in symbiont preference, and more broadly, in relation to self versus non-self recognition. PMID:22225537

Spatial patterns, ecological niches, and interspecific competition of avian brood parasites: inferring from a case study of Korea.

PubMed

Lee, Jin-Won; Noh, Hee-Jin; Lee, Yunkyoung; Kwon, Young-Soo; Kim, Chang-Hoe; Yoo, Jeong-Chil

2014-09-01

Since obligate avian brood parasites depend completely on the effort of other host species for rearing their progeny, the availability of hosts will be a critical resource for their life history. Circumstantial evidence suggests that intense competition for host species may exist not only within but also between species. So far, however, few studies have demonstrated whether the interspecific competition really occurs in the system of avian brood parasitism and how the nature of brood parasitism is related to their niche evolution. Using the occurrence data of five avian brood parasites from two sources of nationwide bird surveys in South Korea and publically available environmental/climatic data, we identified their distribution patterns and ecological niches, and applied species distribution modeling to infer the effect of interspecific competition on their spatial distribution. We found that the distribution patterns of five avian brood parasites could be characterized by altitude and climatic conditions, but overall their spatial ranges and ecological niches extensively overlapped with each other. We also found that the predicted distribution areas of each species were generally comparable to the realized distribution areas, and the numbers of individuals in areas where multiple species were predicted to coexist showed positive relationships among species. In conclusion, despite following different coevolutionary trajectories to adapt to their respect host species, five species of avian brood parasites breeding in South Korea occupied broadly similar ecological niches, implying that they tend to conserve ancestral preferences for ecological conditions. Furthermore, our results indicated that contrary to expectation interspecific competition for host availability between avian brood parasites seemed to be trivial, and thus, play little role in shaping their spatial distributions and ecological niches. Future studies, including the complete ranges of avian brood parasites and ecological niches of host species, will be worthwhile to further elucidate these issues.

Comparative genome-scale modelling of Staphylococcus aureus strains identifies strain-specific metabolic capabilities linked to pathogenicity

PubMed Central

Bosi, Emanuele; Monk, Jonathan M.; Aziz, Ramy K.; Fondi, Marco; Nizet, Victor; Palsson, Bernhard Ø.

2016-01-01

Staphylococcus aureus is a preeminent bacterial pathogen capable of colonizing diverse ecological niches within its human host. We describe here the pangenome of S. aureus based on analysis of genome sequences from 64 strains of S. aureus spanning a range of ecological niches, host types, and antibiotic resistance profiles. Based on this set, S. aureus is expected to have an open pangenome composed of 7,411 genes and a core genome composed of 1,441 genes. Metabolism was highly conserved in this core genome; however, differences were identified in amino acid and nucleotide biosynthesis pathways between the strains. Genome-scale models (GEMs) of metabolism were constructed for the 64 strains of S. aureus. These GEMs enabled a systems approach to characterizing the core metabolic and panmetabolic capabilities of the S. aureus species. All models were predicted to be auxotrophic for the vitamins niacin (vitamin B3) and thiamin (vitamin B1), whereas strain-specific auxotrophies were predicted for riboflavin (vitamin B2), guanosine, leucine, methionine, and cysteine, among others. GEMs were used to systematically analyze growth capabilities in more than 300 different growth-supporting environments. The results identified metabolic capabilities linked to pathogenic traits and virulence acquisitions. Such traits can be used to differentiate strains responsible for mild vs. severe infections and preference for hosts (e.g., animals vs. humans). Genome-scale analysis of multiple strains of a species can thus be used to identify metabolic determinants of virulence and increase our understanding of why certain strains of this deadly pathogen have spread rapidly throughout the world. PMID:27286824

Non-Native Ambrosia Beetles as Opportunistic Exploiters of Living but Weakened Trees

PubMed Central

Ranger, Christopher M.; Schultz, Peter B.; Frank, Steven D.; Chong, Juang H.; Reding, Michael E.

2015-01-01

Exotic Xylosandrus spp. ambrosia beetles established in non-native habitats have been associated with sudden and extensive attacks on a diverse range of living trees, but factors driving their shift from dying/dead hosts to living and healthy ones are not well understood. We sought to characterize the role of host physiological condition on preference and colonization by two invaders, Xylosandrus germanus and Xylosandrus crassiusculus. When given free-choice under field conditions among flooded and non-flooded deciduous tree species of varying intolerance to flooding, beetles attacked flood-intolerant tree species over more tolerant species within 3 days of initiating flood stress. In particular, flood-intolerant flowering dogwood (Cornus florida) sustained more attacks than flood-tolerant species, including silver maple (Acer saccharinum) and swamp white oak (Quercus bicolor). Ethanol, a key host-derived attractant, was detected at higher concentrations 3 days after initiating flooding within stems of flood intolerant species compared to tolerant and non-flooded species. A positive correlation was also detected between ethanol concentrations in stem tissue and cumulative ambrosia beetle attacks. When adult X. germanus and X. crassiusculus were confined with no-choice to stems of flood-stressed and non-flooded C. florida, more ejected sawdust resulting from tunneling activity was associated with the flood-stressed trees. Furthermore, living foundresses, eggs, larvae, and pupae were only detected within galleries created in stems of flood-stressed trees. Despite a capability to attack diverse tree genera, X. germanus and X. crassiusculus efficiently distinguished among varying host qualities and preferentially targeted trees based on their intolerance of flood stress. Non-flooded trees were not preferred or successfully colonized. This study demonstrates the host-selection strategy exhibited by X. germanus and X. crassiusculus in non-native habitats involves detection of stress-induced ethanol emission and early colonization of living but weakened trees. PMID:26134522

Non-Native Ambrosia Beetles as Opportunistic Exploiters of Living but Weakened Trees.

PubMed

Ranger, Christopher M; Schultz, Peter B; Frank, Steven D; Chong, Juang H; Reding, Michael E

2015-01-01

Exotic Xylosandrus spp. ambrosia beetles established in non-native habitats have been associated with sudden and extensive attacks on a diverse range of living trees, but factors driving their shift from dying/dead hosts to living and healthy ones are not well understood. We sought to characterize the role of host physiological condition on preference and colonization by two invaders, Xylosandrus germanus and Xylosandrus crassiusculus. When given free-choice under field conditions among flooded and non-flooded deciduous tree species of varying intolerance to flooding, beetles attacked flood-intolerant tree species over more tolerant species within 3 days of initiating flood stress. In particular, flood-intolerant flowering dogwood (Cornus florida) sustained more attacks than flood-tolerant species, including silver maple (Acer saccharinum) and swamp white oak (Quercus bicolor). Ethanol, a key host-derived attractant, was detected at higher concentrations 3 days after initiating flooding within stems of flood intolerant species compared to tolerant and non-flooded species. A positive correlation was also detected between ethanol concentrations in stem tissue and cumulative ambrosia beetle attacks. When adult X. germanus and X. crassiusculus were confined with no-choice to stems of flood-stressed and non-flooded C. florida, more ejected sawdust resulting from tunneling activity was associated with the flood-stressed trees. Furthermore, living foundresses, eggs, larvae, and pupae were only detected within galleries created in stems of flood-stressed trees. Despite a capability to attack diverse tree genera, X. germanus and X. crassiusculus efficiently distinguished among varying host qualities and preferentially targeted trees based on their intolerance of flood stress. Non-flooded trees were not preferred or successfully colonized. This study demonstrates the host-selection strategy exhibited by X. germanus and X. crassiusculus in non-native habitats involves detection of stress-induced ethanol emission and early colonization of living but weakened trees.

A Second β-Hexosaminidase Encoded in the Streptococcus pneumoniae Genome Provides an Expanded Biochemical Ability to Degrade Host Glycans*

PubMed Central

Robb, Melissa; Robb, Craig S.; Higgins, Melanie A.; Hobbs, Joanne K.; Paton, James C.; Boraston, Alisdair B.

2015-01-01

An important facet of the interaction between the pathogen Streptococcus pneumoniae (pneumococcus) and its human host is the ability of this bacterium to process host glycans. To achieve cleavage of the glycosidic bonds in host glycans, S. pneumoniae deploys a wide array of glycoside hydrolases. Here, we identify and characterize a new family 20 glycoside hydrolase, GH20C, from S. pneumoniae. Recombinant GH20C possessed the ability to hydrolyze the β-linkages joining either N-acetylglucosamine or N-acetylgalactosamine to a wide variety of aglycon residues, thus revealing this enzyme to be a generalist N-acetylhexosaminidase in vitro. X-ray crystal structures were determined for GH20C in a ligand-free form, in complex with the N-acetylglucosamine and N-acetylgalactosamine products of catalysis and in complex with both gluco- and galacto-configured inhibitors O-(2-acetamido-2-deoxy-d-glucopyranosylidene)amino N-phenyl carbamate (PUGNAc), O-(2-acetamido-2-deoxy-d-galactopyranosylidene)amino N-phenyl carbamate (GalPUGNAc), N-acetyl-d-glucosamine-thiazoline (NGT), and N-acetyl-d-galactosamine-thiazoline (GalNGT) at resolutions from 1.84 to 2.7 Å. These structures showed N-acetylglucosamine and N-acetylgalactosamine to be recognized via identical sets of molecular interactions. Although the same sets of interaction were maintained with the gluco- and galacto-configured inhibitors, the inhibition constants suggested preferred recognition of the axial O4 when an aglycon moiety was present (Ki for PUGNAc > GalPUGNAc) but preferred recognition of an equatorial O4 when the aglycon was absent (Ki for GalNGT > NGT). Overall, this study reveals GH20C to be another tool that is unique in the arsenal of S. pneumoniae and that it may implement the effort of the bacterium to utilize and/or destroy the wide array of host glycans that it may encounter. PMID:26491009

Endemic Mimosa species from Mexico prefer alphaproteobacterial rhizobial symbionts.

PubMed

Bontemps, Cyril; Rogel, Marco Antonio; Wiechmann, Anja; Mussabekova, Assel; Moody, Sarah; Simon, Marcelo F; Moulin, Lionel; Elliott, Geoffrey N; Lacercat-Didier, Laurence; Dasilva, Cindy; Grether, Rosaura; Camargo-Ricalde, Sara L; Chen, Weimin; Sprent, Janet I; Martínez-Romero, Esperanza; Young, J Peter W; James, Euan K

2016-01-01

The legume genus Mimosa has > 500 species, with two major centres of diversity, Brazil (c. 350 spp.) and Mexico (c. 100 spp.). In Brazil most species are nodulated by Burkholderia. Here we asked whether this is also true of native and endemic Mexican species. We have tested this apparent affinity for betaproteobacteria by examining the symbionts of native and endemic species of Mimosa in Mexico, especially from the central highlands where Mimosa spp. have diversified. Nodules were tested for betaproteobacteria using in situ immunolocalization. Rhizobia isolated from the nodules were genetically characterized and tested for their ability to nodulate Mimosa spp. Immunological analysis of 25 host taxa suggested that most (including all the highland endemics) were not nodulated by betaproteobacteria. Phylogenetic analyses of 16S rRNA, recA, nodA, nodC and nifH genes from 87 strains isolated from 20 taxa confirmed that the endemic Mexican Mimosa species favoured alphaproteobacteria in the genera Rhizobium and Ensifer: this was confirmed by nodulation tests. Host phylogeny, geographic isolation and coevolution with symbionts derived from very different soils have potentially contributed to the striking difference in the choice of symbiotic partners by Mexican and Brazilian Mimosa species. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

So close and yet so far – Molecular Microbiology of Campylobacter fetus subspecies

PubMed Central

Sprenger, H.; Zechner, E. L.; Gorkiewicz, G.

2012-01-01

Campylobacter fetus comprises two subspecies, C. fetus subsp. fetus and C. fetus subsp. venerealis, which are considered emerging pathogens in humans and animals. Comparisons at the genome level have revealed modest subspecies-specific variation; nevertheless, these two subspecies show distinct host and niche preferences. C. fetus subsp. fetus is a commensal and pathogen of domesticated animals that can be transmitted to humans via contaminated food. The clinical features of human infection can be severe, especially in impaired hosts. In contrast, C. fetus subsp. venerealis is a sexually transmitted pathogen essentially restricted to cattle. Infections leading to bovine venereal campylobacteriosis cause substantial economic losses due to abortion and infertility. Recent genome sequencing of the two subspecies has advanced our understanding of C. fetus adaptations through comparative genomics and the identification of subspecies-specific gene regions predicted to be involved in pathogenesis. The most striking difference between the subspecies is the highly subspecies-specific association of a pathogenicity island in the C. fetus subsp. venerealis chromosome. The inserted region encodes a Type 4 secretion system, which contributes to virulence properties of this organism in vitro. This review describes the main differences in epidemiological, phenotypic, and molecular characteristics of the two subspecies and summarizes recent advances towards understanding the molecular mechanisms of C. fetus pathogenesis. PMID:24611123

A correlation between macronutrient balancing and insect host-plant range: evidence from the specialist caterpillar Spodoptera exempta (Walker).

PubMed

Lee, Kwang Pum; Raubenheimer, David; Behmer, Spencer T; Simpson, Stephen J

2003-12-01

In an earlier study, we showed that the ingestive responses of the generalist caterpillar Spodoptera littoralis to foods imbalanced in their protein:carbohydrate content is similar to generalist locusts, but differs from that of specialist-feeding locusts. Here we further pursued the comparison by repeating the experiments using a closely related specialist caterpillar, Spodoptera exempta. First, caterpillars were allowed to self-compose a diet of preferred protein:carbohydrate balance by mixing between nutritionally complementary foods. Then, they were confined to one of five imbalanced foods, in which we measured the trade-off between over- and under-ingesting the two nutrients. On complementary foods, the caterpillars actively regulated their protein and carbohydrate intake. In the no-choice experiment, those fed excess-protein foods ingested small surpluses of protein compared with generalist feeders, thus showing a pattern of nutrient balancing similar to that observed in specialist locusts. Utilisation data indicated that ingested excesses and deficits were to some extent offset by differential utilisation. Evidence also showed that post-ingestive responses of the specialist S. exempta were less flexible than those observed in the generalist S. littoralis, a pattern which is again in accordance with comparisons of acridids differing in their host-plant range.

The nonstructural proteins of Pneumoviruses are remarkably distinct in substrate diversity and specificity.

PubMed

Ribaudo, Michael; Barik, Sailen

2017-11-06

Interferon (IFN) inhibits viruses by inducing several hundred cellular genes, aptly named 'interferon (IFN)-stimulated genes' (ISGs). The only two RNA viruses of the Pneumovirus genus of the Paramyxoviridae family, namely Respiratory Syncytial Virus (RSV) and Pneumonia Virus of Mice (PVM), each encode two nonstructural (NS) proteins that share no sequence similarity but yet suppress IFN. Since suppression of IFN underlies the ability of these viruses to replicate in the host cells, the mechanism of such suppression has become an important area of research. This Short Report is an important extension of our previous efforts in defining this mechanism. We show that, like their PVM counterparts, the RSV NS proteins also target multiple members of the ISG family. While significantly extending the substrate repertoire of the RSV NS proteins, these results, unexpectedly, also reveal that the target preferences of the NS proteins of the two viruses are entirely different. This is surprising since the two Pneumoviruses are phylogenetically close with similar genome organization and gene function, and the NS proteins of both also serve as suppressors of host IFN response. The finding that the NS proteins of the two highly similar viruses suppress entirely different members of the ISG family raises intriguing questions of pneumoviral NS evolution and mechanism of action.

The Mechanisms for Within-Host Influenza Virus Control Affect Model-Based Assessment and Prediction of Antiviral Treatment

PubMed Central

Cao, Pengxing

2017-01-01

Models of within-host influenza viral dynamics have contributed to an improved understanding of viral dynamics and antiviral effects over the past decade. Existing models can be classified into two broad types based on the mechanism of viral control: models utilising target cell depletion to limit the progress of infection and models which rely on timely activation of innate and adaptive immune responses to control the infection. In this paper, we compare how two exemplar models based on these different mechanisms behave and investigate how the mechanistic difference affects the assessment and prediction of antiviral treatment. We find that the assumed mechanism for viral control strongly influences the predicted outcomes of treatment. Furthermore, we observe that for the target cell-limited model the assumed drug efficacy strongly influences the predicted treatment outcomes. The area under the viral load curve is identified as the most reliable predictor of drug efficacy, and is robust to model selection. Moreover, with support from previous clinical studies, we suggest that the target cell-limited model is more suitable for modelling in vitro assays or infection in some immunocompromised/immunosuppressed patients while the immune response model is preferred for predicting the infection/antiviral effect in immunocompetent animals/patients. PMID:28933757

Fungal endophytes of aquatic macrophytes: diverse host-generalists characterized by tissue preferences and geographic structure

PubMed Central

Sandberg, Dustin C.; Battista, Lorna J.; Arnold, A. Elizabeth

2014-01-01

Most studies of endophytic symbionts have focused on terrestrial plants, neglecting the ecologically and economically important plants present in aquatic ecosystems. We evaluated the diversity, composition, host- and tissue affiliations, and geographic structure of fungal endophytes associated with common aquatic plants in northern Arizona, USA. Endophytes were isolated in culture from roots and photosynthetic tissues during two growing seasons. A total of 226 isolates representing 60 putative species was recovered from 9,600 plant tissue segments. Although isolation frequency was low, endophytes were phylogenetically diverse and species-rich. Comparisons among the most thoroughly sampled species and reservoirs revealed that isolation frequency and diversity did not differ significantly between collection periods, among species, among reservoirs, or as a function of depth. However, community structure differed significantly among reservoirs and tissue types. Phylogenetic analyses of a focal genus (Penicillium) corroborated estimates of species boundaries and informed community analyses, highlighting clade- and genotype-level affiliations of aquatic endophytes with both sediment- and waterborne fungi, and endophytes of proximate terrestrial plants. Together these analyses provide a first quantitative examination of endophytic associations in roots and foliage of aquatic plants and can be used to optimize survey strategies for efficiently capturing fungal biodiversity at local and regional scales. PMID:24402358

Effects of cucumber mosaic virus-infected chilli plants on non-vector Bemisia tabaci (Hemiptera: Aleyrodidae).

PubMed

Saad, Khalid A; Mohamad Roff, M N; Hallett, Rebecca H; ABd-Ghani, Idris B

2017-06-08

Plant virus infections are known to alter host plant attractiveness and suitability for insect herbivores. This study was conducted to determine how cucumber mosaic virus (CMV)-infected chilli plants affect the fitness and settling preferences of nonvector whitefly, Bemisia tabaci adults under dual-choice conditions with volatile organic compounds analyzed using solid phase microextraction coupled with gas chromatography-mass spectrometry (GC-MS). Results showed that the presence of CMV in chilli plants substantially affects the settling preferences of the B. tabaci, which preferred to settle on noninfected plants. Duration of the egg stage and the longevity and fecundity of adult B. tabaci on CMV-infected chilli plants were not markedly different from those on noninfected chilli plants. In contrast, the developmental time from egg to adult was significantly reduced in CMV-infected chilli plants compared to the noninfected plants. The results also showed that CMV-infected chilli plants released significantly more linalool and phenylacetaldehyde than noninfected plants. Overall, it was suggested that the behavioral response of B. tabaci might be modified by CMV-infected plants, which alter the release of specific headspace volatiles. Based on these results, the modification of plant volatile profiles may help in enhancing the effectiveness of biological control and the protection of crop plants against B. tabaci. © 2017 Institute of Zoology, Chinese Academy of Sciences.

The Ed Media Center: A Second Life Professional Development Model for Relational Aesthetics

ERIC Educational Resources Information Center

Julian, June; Crooks, Julian Glynn

2014-01-01

The Ed Media Center in Second Life provides multiple professional development opportunities for art educators to explore the educational potential of virtual worlds together. Since it's launch in 2009, it has hosted numerous events that address contemporary students' learning preferences and that enable artists and art educators to become…

Preference of dendrophagous insects for forest borders

Treesearch

Andrey V. Gurov

1991-01-01

Numerous investigations have shown that forest insect outbreaks usually occur in specific habitats. Frequently these outbreaks do not generally extend to other territories occupied by these same host trees. Moreover, in every stand subjected to an outbreak, both slightly undamaged plots and heavily damaged plots are found. Perhaps some plots are initially more...

Combined use of herbivore-induced plant volatiles and sex pheromones for mate location in braconid parasitoids

USDA-ARS?s Scientific Manuscript database

Herbivore-induced plant volatiles (HIPVs) are important cues for female parasitic wasps to find hosts. Here, we investigated the possibility that HIPVs may also serve parasitoids as cues to locate mates. To test this, the odor preferences of four braconid wasps – the gregarious parasitoid Cotesia gl...

Agrilus auroguttatus (Coleoptera: Buprestidae) seasonal development within Quercus agrifolia (Fagales: Fagaceae) in southern California

Treesearch

L.J. Haavik; T.W. Coleman; M.L. Flint; R.C. Venette; S.J. Seybold

2013-01-01

We investigated seasonal development of the goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), and physical conditions of the phloem within a preferred host species, coast live oak, Quercus agrifolia Née. We sampled infested trees on a monthly basis at two sites in southern California throughout...

Association of ‘Candidatus Liberibacter asiaticus’, the causal agent of citrus huanglongbing in Murraya paniculata and Diaphorina citri in Thailand

USDA-ARS?s Scientific Manuscript database

Orange jasmine, Murraya paniculata, is a preferred alternative host for the Asian citrus psyllid, the primary vector of citrus Huanglongbing (HLB) disease caused by ‘Candidatus Liberibacter asiaticus’ (Las). M. paniculata plant samples and psyllids on the Murraya plants from ten diverse geographical...

Teaching Generation Text: Using Cell Phones to Enhance Learning

ERIC Educational Resources Information Center

Nielsen, Lisa; Webb, Willyn

2011-01-01

"Teaching Generation Text" shows how teachers can turn cell phones into an educational opportunity instead of an annoying distraction. With a host of innovative ideas, activities, lessons, and strategies, Nielsen and Webb offer a unique way to use students' preferred method of communication in the classroom. Cell phones can remind students to…

Relative longevity of adult Nezara viridula (Hemiptera: Pentatomidae) in cotton, peanut and soybean

USDA-ARS?s Scientific Manuscript database

Producers in the Southeastern US face significant crop losses from the stink bugs, Nezara viridula, Euschistus servus, and Chinavia hilaris. Cotton, peanut, and soybean are major agronomic crops and host plants of stink bugs in the region. N. viridula colonize and feed in peanut. Stink bugs prefer t...

Beyond Regular Employment Contexts: The Transferability of Pay, Satisfaction and Performance Linkages to Internships

ERIC Educational Resources Information Center

Rose, Philip

2015-01-01

Internship participation has undergone rapid expansion over the last three decades, to the point where today many interns and host organizations regard internships as the preferred pathway into entry-level professional positions. However, organizational research has largely neglected the investigation of internships as an employment context, thus…

Complete Genome Sequences of Bacillus Phages Janet and OTooleKemple52

PubMed Central

2018-01-01

ABSTRACT We report here the genome sequences of two novel Bacillus cereus group-infecting bacteriophages, Janet and OTooleKemple52. These bacteriophages are double-stranded DNA-containing Myoviridae isolated from soil samples. While their genomes share a high degree of sequence identity with one another, their host preferences are unique. PMID:29748396

Perceptual Learning Style Preferences among Iranian Graduate Students

ERIC Educational Resources Information Center

Naserieh, Farid; Sarab, Mohammad Reza Anani

2013-01-01

Research suggests that a host of cognitive, affective, and perceptual variables are at work when individuals go about the task of second or foreign language learning. Among these variables are learning styles that are habitual ways of perceiving, processing, and storing information. This study was conducted as a response to Isemonger and…

Deciding Access to Work-Integrated Learning: Human Resource Professionals as Gatekeepers

ERIC Educational Resources Information Center

Mackaway, Jacqueline; Winchester-Seeto, Theresa

2018-01-01

Universities, industry and professional bodies advocate work-integrated learning (WIL) as a valuable way to prepare graduates to meet the challenges of contemporary society. When organizations preference particular students over others to host on placement, the full individual and collective potential of WIL is not realized. This paper reports…

Vitex agnus-castus is a preferred host plant for Hyalesthes obsoletus.

PubMed

Sharon, Rakefet; Soroker, Victoria; Wesley, S Daniel; Zahavi, Tirtza; Harari, Ally; Weintraub, Phyllis G

2005-05-01

Hyalesthes obsoletus Signoret (Homoptera: Cixiidae) is a polyphagous planthopper that transmits stolbur phytoplasma (a causative agent of "yellows" disease) to various weeds, members of the Solanaceae, and wine grapes (Vitis vinifera L.) in Europe and the Middle East. Planthoppers were collected by hand vacuuming eight native plant species. Vitex agnus-castus L., a shrub in the Verbenaceae, hosted the largest number of H. obsoletus, although Olea europaea L. also served as a host for adults. Using a Y-olfactometer, we compared the planthoppers relative preference for V. agnus-castus, Convolvulus arvensis, and V. vinifera. V. agnus-castus was more attractive to both male and female H. obsoletus than the other plants. H. obsoletus antennal response was stronger to volatiles collected from V. agnuscastus than from Cabernet Sauvignon variety of V. vinifera. To determine if V. agnus-castus would serve as a reservoir for the pathogen, H. obsoletus were collected from leaf and stem samples of native V. agnus-castus, and were tested by polymerase chain reaction (PCR) for the presence of phytoplasma DNA. While 14% and 25% (2003 and 2004, respectively) of the insects tested positive for phytoplasma DNA, none of the plant samples tested positive. To determine if V. agnus-castus could serve as a host plant for the development of the planthopper, we placed emergence cages beneath field shrubs and enclosed wild-caught H. obsoletus in a cage with a potted young shrub. We found adult H. obsoletus in the emergence cases and planthopper nymphs in the soil of the potted plant. We concluded that V. agnus-castus is attractive to H. obsoletus, which seems to be refractory to phytoplasma infections and warrants further testing as a trap plant near vineyards.

Distribution and abundance of mymarid parasitoids (Hymenoptera: Mymaridae) of Sophonia rufofascia Kuoh and Kuoh (Homoptera: Cicadellidae)in Hawaii

USGS Publications Warehouse

Yang, P.; Foote, D.; Alyokhin, A.V.; Lenz, L.; Messing, R.H.

2002-01-01

The abundance of mymarid parasitoids attacking the two-spotted leafhopper (Sophonia rufofascia [Kuoh and Kuoh]), a polyphagous pest recently adventive to Hawaii, was monitored using yellow sticky cards deployed in several areas on the islands of Kauai and Hawaii. The yellow cards captured Chaetomymar sp. nr bagicha Narayanan, Subba Rao, & Kaur and Schizophragma bicolor (Dozier), both adventive species, and Polynema sp. Haliday, which is endemic to Hawaii (Hymenoptera: Mymaridae). The former two species were most abundant at all sites. On Kauai, there was a negative correlation between the captures of C. sp. nr bagicha and those of Polynema sp. Throughout the season, the increase in parasitoid numbers generally followed the increase in leafhopper numbers. C. sp. nr. bagicha and S. bicolor showed distinct habitat preferences. Removal of Myrica faya Aiton, an invasive weed that is a highly preferred two-spotted leafhopper host, decreased the overall numbers of captured parasitoids, but led to a twofold increase in the ratio of trapped parasitoids/hosts in weed-free areas. ?? 2002 Elsevier Science (USA).

Mutual Use of Trail-Following Chemical Cues by a Termite Host and Its Inquiline

PubMed Central

Cristaldo, Paulo Fellipe; DeSouza, Og; Krasulová, Jana; Jirošová, Anna; Kutalová, Kateřina; Lima, Eraldo Rodrigues; Šobotník, Jan; Sillam-Dussès, David

2014-01-01

Termite nests are often secondarily inhabited by other termite species ( = inquilines) that cohabit with the host. To understand this association, we studied the trail-following behaviour in two Neotropical species, Constrictotermes cyphergaster (Termitidae: Nasutitermitinae) and its obligatory inquiline, Inquilinitermes microcerus (Termitidae: Termitinae). Using behavioural experiments and chemical analyses, we determined that the trail-following pheromone of C. cyphergaster is made of neocembrene and (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol. Although no specific compound was identified in I. microcerus, workers were able to follow the above compounds in behavioural bioassays. Interestingly, in choice tests, C. cyphergaster prefers conspecific over heterospecific trails while I. microcerus shows the converse behaviour. In no-choice tests with whole body extracts, C. cyphergaster showed no preference for, while I. microcerus clearly avoided heterospecific trails. This seems to agree with the hypothesis that trail-following pheromones may shape the cohabitation of C. cyphergaster and I. microcerus and reinforce the idea that their cohabitation is based on conflict-avoiding strategies. PMID:24465533

Mutual use of trail-following chemical cues by a termite host and its inquiline.

PubMed

Cristaldo, Paulo Fellipe; Desouza, Og; Krasulová, Jana; Jirošová, Anna; Kutalová, Kateřina; Lima, Eraldo Rodrigues; Sobotník, Jan; Sillam-Dussès, David

2014-01-01

Termite nests are often secondarily inhabited by other termite species ( = inquilines) that cohabit with the host. To understand this association, we studied the trail-following behaviour in two Neotropical species, Constrictotermes cyphergaster (Termitidae: Nasutitermitinae) and its obligatory inquiline, Inquilinitermes microcerus (Termitidae: Termitinae). Using behavioural experiments and chemical analyses, we determined that the trail-following pheromone of C. cyphergaster is made of neocembrene and (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol. Although no specific compound was identified in I. microcerus, workers were able to follow the above compounds in behavioural bioassays. Interestingly, in choice tests, C. cyphergaster prefers conspecific over heterospecific trails while I. microcerus shows the converse behaviour. In no-choice tests with whole body extracts, C. cyphergaster showed no preference for, while I. microcerus clearly avoided heterospecific trails. This seems to agree with the hypothesis that trail-following pheromones may shape the cohabitation of C. cyphergaster and I. microcerus and reinforce the idea that their cohabitation is based on conflict-avoiding strategies.

The genetic architecture of ecological adaptation: intraspecific variation in host plant use by the lepidopteran crop pest Chloridea virescens.

PubMed

Oppenheim, Sara J; Gould, Fred; Hopper, Keith R

2018-03-01

Intraspecific variation in ecologically important traits is a cornerstone of Darwin's theory of evolution by natural selection. The evolution and maintenance of this variation depends on genetic architecture, which in turn determines responses to natural selection. Some models suggest that traits with complex architectures are less likely to respond to selection than those with simple architectures, yet rapid divergence has been observed in such traits. The simultaneous evolutionary lability and genetic complexity of host plant use in the Lepidopteran subfamily Heliothinae suggest that architecture may not constrain ecological adaptation in this group. Here we investigate the response of Chloridea virescens, a generalist that feeds on diverse plant species, to selection for performance on a novel host, Physalis angulata (Solanaceae). P. angulata is the preferred host of Chloridea subflexa, a narrow specialist on the genus Physalis. In previous experiments, we found that the performance of C. subflexa on P. angulata depends on many loci of small effect distributed throughout the genome, but whether the same architecture would be involved in the generalist's adoption of P. angulata was unknown. Here we report a rapid response to selection in C. virescens for performance on P. angulata, and establish that the genetic architecture of intraspecific variation is quite similar to that of the interspecific differences in terms of the number, distribution, and effect sizes of the QTL involved. We discuss the impact of genetic architecture on the ability of Heliothine moths to respond to varying ecological selection pressures.

A Trichomonas vaginalis Rhomboid Protease and Its Substrate Modulate Parasite Attachment and Cytolysis of Host Cells

PubMed Central

Riestra, Angelica M.; Gandhi, Shiv; Sweredoski, Michael J.; Moradian, Annie; Hess, Sonja; Urban, Sinisa; Johnson, Patricia J.

2015-01-01

Trichomonas vaginalis is an extracellular eukaryotic parasite that causes the most common, non-viral sexually transmitted infection worldwide. Although disease burden is high, molecular mechanisms underlying T. vaginalis pathogenesis are poorly understood. Here, we identify a family of putative T. vaginalis rhomboid proteases and demonstrate catalytic activity for two, TvROM1 and TvROM3, using a heterologous cell cleavage assay. The two T. vaginalis intramembrane serine proteases display different subcellular localization and substrate specificities. TvROM1 is a cell surface membrane protein and cleaves atypical model rhomboid protease substrates, whereas TvROM3 appears to localize to the Golgi apparatus and recognizes a typical model substrate. To identify TvROM substrates, we interrogated the T. vaginalis surface proteome using both quantitative proteomic and bioinformatic approaches. Of the nine candidates identified, TVAG_166850 and TVAG_280090 were shown to be cleaved by TvROM1. Comparison of amino acid residues surrounding the predicted cleavage sites of TvROM1 substrates revealed a preference for small amino acids in the predicted transmembrane domain. Over-expression of TvROM1 increased attachment to and cytolysis of host ectocervical cells. Similarly, mutations that block the cleavage of a TvROM1 substrate lead to its accumulation on the cell surface and increased parasite adherence to host cells. Together, these data indicate a role for TvROM1 and its substrate(s) in modulating attachment to and lysis of host cells, which are key processes in T. vaginalis pathogenesis. PMID:26684303

Host range, host ecology, and distribution of more than 11800 fish parasite species

USGS Publications Warehouse

Strona, Giovanni; Palomares, Maria Lourdes D.; Bailly, Nicholas; Galli, Paolo; Lafferty, Kevin D.

2013-01-01

Our data set includes 38 008 fish parasite records (for Acanthocephala, Cestoda, Monogenea, Nematoda, Trematoda) compiled from the scientific literature, Internet databases, and museum collections paired to the corresponding host ecological, biogeographical, and phylogenetic traits (maximum length, growth rate, life span, age at maturity, trophic level, habitat preference, geographical range size, taxonomy). The data focus on host features, because specific parasite traits are not consistently available across records. For this reason, the data set is intended as a flexible resource able to extend the principles of ecological niche modeling to the host–parasite system, providing researchers with the data to model parasite niches based on their distribution in host species and the associated host features. In this sense, the database offers a framework for testing general ecological, biogeographical, and phylogenetic hypotheses based on the identification of hosts as parasite habitat. Potential applications of the data set are, for example, the investigation of species–area relationships or the taxonomic distribution of host-specificity. The provided host–parasite list is that currently used by Fish Parasite Ecology Software Tool (FishPEST, http://purl.oclc.org/fishpest), which is a website that allows researchers to model several aspects of the relationships between fish parasites and their hosts. The database is intended for researchers who wish to have more freedom to analyze the database than currently possible with FishPEST. However, for readers who have not seen FishPEST, we recommend using this as a starting point for interacting with the database.