0000000001265313
AUTHOR
Tobias Engl
Nitric oxide radicals are emitted by wasp eggs to kill mold fungi
Detrimental microbes caused the evolution of a great diversity of antimicrobial defenses in plants and animals. Insects developing underground seem particularly threatened. Here we show that the eggs of a solitary digger wasp, the European beewolf Philanthus triangulum, emit large amounts of gaseous nitric oxide (NO⋅) to protect themselves and their provisions, paralyzed honeybees, against mold fungi. We provide evidence that a NO-synthase (NOS) is involved in the generation of the extraordinary concentrations of nitrogen radicals in brood cells (~1500 ppm NO⋅ and its oxidation product NO2⋅). Sequencing of the beewolf NOS gene revealed no conspicuous differences to related species. However,…
Influence of microbial symbionts on insect pheromones
Covering: up to 2018 Pheromones serve as chemical signals between individuals of the same species and play important roles for mate localization and mate choice as well as other social interactions in insects. A growing body of literature indicates that microbial symbionts can modulate their hosts' chemical profiles, mate choice decisions and social behavior. This modulation can occur by the direct biosynthesis of pheromone components or the provisioning of precursors, or through general changes in the metabolite pool of the host and its resource allocation into pheromone production. Here we review and discuss the contexts in which microbial modulation of intraspecific communication in inse…
Additional file 1: of Effect of antibiotic treatment and gamma-irradiation on cuticular hydrocarbon profiles and mate choice in tsetse flies (Glossina m. morsitans)
Comparison of CHC profiles of untreated (Ctr) and tetracycline-treated (Tet) (a) female and (b) male tsetse flies (G. m. morsitans) across the three different experiments. (PDF 1363Â kb)
Additional file 3: of Effect of antibiotic treatment and gamma-irradiation on cuticular hydrocarbon profiles and mate choice in tsetse flies (Glossina m. morsitans)
Effect of the time point of gamma-irradiation on CHC profiles of individually reared 10Â day old adult G. m. morsitans males. Discriminant analysis based on log-ratio transformed relative amounts across irradiation time points (early and late pupal development and as young adults). (PDF 1354Â kb)
Effect of antibiotic treatment and gamma-irradiation on cuticular hydrocarbon profiles and mate choice in tsetse flies (Glossina m. morsitans).
Background Symbiotic microbes represent a driving force of evolutionary innovation by conferring novel ecological traits to their hosts. Many insects are associated with microbial symbionts that contribute to their host’s nutrition, digestion, detoxification, reproduction, immune homeostasis, and defense. In addition, recent studies suggest a microbial involvement in chemical communication and mating behavior, which can ultimately impact reproductive isolation and, hence, speciation. Here we investigated whether a disruption of the microbiota through antibiotic treatment or irradiation affects cuticular hydrocarbon profiles, and possibly mate choice behavior in the tsetse fly, Glossina mors…
Additional file 3: of Effect of antibiotic treatment and gamma-irradiation on cuticular hydrocarbon profiles and mate choice in tsetse flies (Glossina m. morsitans)
Effect of the time point of gamma-irradiation on CHC profiles of individually reared 10Â day old adult G. m. morsitans males. Discriminant analysis based on log-ratio transformed relative amounts across irradiation time points (early and late pupal development and as young adults). (PDF 1354Â kb)
Nutritional symbionts enhance structural defence against predation and fungal infection in a grain pest beetle
ABSTRACT Many insects benefit from bacterial symbionts that provide essential nutrients and thereby extend the hosts’ adaptive potential and their ability to cope with challenging environments. However, the implications of nutritional symbioses for the hosts’ defence against natural enemies remain largely unstudied. Here, we investigated whether the cuticle-enhancing nutritional symbiosis of the saw-toothed grain beetle Oryzaephilus surinamensis confers protection against predation and fungal infection. We exposed age-defined symbiotic and symbiont-depleted (aposymbiotic) beetles to two antagonists that must actively penetrate the cuticle for a successful attack: wolf spiders (Lycosidae) an…
Ancient symbiosis confers desiccation resistance to stored grain pest beetles
AbstractMicrobial symbionts of insects provide a range of ecological traits to their hosts that are beneficial in the context of biotic interactions. However, little is known about insect symbiont-mediated adaptation to the abiotic environment, e.g. temperature and humidity. Here we report on an ancient (~400 Mya) clade of intracellular, bacteriome-located Bacteroidetes symbionts that are associated withgrain and wood pest beetles of the phylogenetically distant families Silvanidae and Bostrichidae. In the saw-toothed grain beetle Oryzaephilus surinamensis, we demonstrate that the symbionts affect cuticle thickness, melanization and hydrocarbon profile, enhancing desiccation resistance and …
Microbial symbionts expanding or constraining abiotic niche space in insects
In addition to their well-studied contributions to their host’s nutrition, digestion, and defense, microbial symbionts of insects are increasingly found to affect their host’s response toward abiotic stressors. In particular, symbiotic microbes can reduce or enhance tolerance to temperature extremes, improve desiccation resistance by aiding cuticle biosynthesis and sclerotization, and detoxify heavy metals. As such, individual symbionts or microbial communities can expand or constrain the abiotic niche space of their host and determine its adaptability to fluctuating environments. In light of the increasing impact of humans on climate and environment, a better understanding of host-microbe …
Love at first sniff: a spermatophore-associated pheromone mediates partner attraction in a collembolan species
Mate choice is essential in most animals, as a good choice of mating partner largely determines reproductive success. Much evidence shows that olfactory cues play an important role in mate choice. However, the integration of chemical, visual and acoustic cues, often used when both partners meet, makes it hard to test whether olfaction alone can mediate reproductive decisions. Interestingly, several invertebrates have adopted a mating system where males deposit their sperm (packed in spermatophores) in the environment for females to pick up with no visual contact between the sexes. In this case the male cue is conveyed by the spermatophore only. Earlier studies on a species with indirect spe…
Incipient genome erosion and metabolic streamlining for antibiotic production in a defensive symbiont
Significance Genome reduction is commonly observed in bacteria of several phyla engaging in obligate nutritional symbioses with insects. In Actinobacteria, however, little is known about the process of genome evolution, despite their importance as prolific producers of antibiotics and their increasingly recognized role as defensive partners of insects and other organisms. Here, we show that “Streptomyces philanthi,” a defensive symbiont of digger wasps, has a G+C-enriched genome in the early stages of erosion, with inactivating mutations in a large proportion of genes, causing dependency on its hosts for certain nutrients, which was validated in axenic symbiont cultures. Additionally, overe…
Additional file 2: of Effect of antibiotic treatment and gamma-irradiation on cuticular hydrocarbon profiles and mate choice in tsetse flies (Glossina m. morsitans)
Effect of gamma-irradiation dose and time point on CHC profiles of 10Â day old individually reared adult G. m. morsitans males. Discriminant analysis based on log-ratio transformed relative amounts across all treatment groups (time points and irradiation doses). (PDF 1353Â kb)
Data from: Ancient symbiosis confers desiccation resistance to stored grain pest beetles
Microbial symbionts of insects provide a range of ecological traits to their hosts that are beneficial in the context of biotic interactions. However, little is known about insect symbiont-mediated adaptation to the abiotic environment, e.g. temperature and humidity. Here we report on an ancient clade of intracellular, bacteriome-located Bacteroidetes symbionts that are associated with grain and wood pest beetles of the phylogenetically distant families Silvanidae and Bostrichidae. In the saw-toothed grain beetle Oryzaephilus surinamensis, we demonstrate that the symbionts affect cuticle thickness, melanization and hydrocarbon profile, enhancing desiccation resistance and thereby strongly i…