Domestication-related changes in sexual performance of Queensland fruit fly
. INSECT SCIENCE 2021
In Sterile Insect Technique (SIT) programs, massive numbers of insects are reared, sterilized, and released in the field to impede reproduction of pest populations. The domestication and rearing processes used to produce insects for SIT programs may have significant evolutionary impacts on life history and reproductive biology. We assessed the effects of domestication on sexual performance of laboratory reared Queensland fruit fly,Bactrocera tryoni, by comparing an old (49 generations) and a young colony (5 generations). We evaluated mating propensity, mating latency, copula duration, sperm transfer, and ability to induce sexual inhibition in mates. Overall, both males and females from the old colony had greater mating propensity than those from the young colony. Copula duration was longer when females were from the old colony. There was no evidence of sexual isolation between the colonies as males and females from the two colonies had similar propensity to mate with flies from either colony. Males from the old colony transferred more sperm regardless of which colony their mate was from. Finally, males from both colonies were similarly able to induce sexual inhibition in their mates and were also similarly able to secure copulations with already-mated females. Positive effects of domestication on sperm transfer, coupled with maintained ability to induce sexual inhibition in mates and to secure copulations with previously mated females, highlights that domestication may have little effect, or even positive effects, on some aspects of sexual performance that may advantage mass-rearedB. tryoniin SIT programs.
Sex-Dependent Effects of the Microbiome on Foraging and Locomotion in Drosophila suzukii
. FRONTIERS IN MICROBIOLOGY 2021
There is growing evidence that symbiotic microbes can influence multiple nutrition-related behaviors of their hosts, including locomotion, feeding, and foraging. However, how the microbiome affects nutrition-related behavior is largely unknown. Here, we demonstrate clear sexual dimorphism in how the microbiome affects foraging behavior of a frugivorous fruit fly, Drosophila suzukii. Female flies deprived of their microbiome (axenic) were consistently less active in foraging on fruits than their conventional counterparts, even though they were more susceptible to starvation and starvation-induced locomotion was notably more elevated in axenic than conventional females. Such behavioral change was not observed in male flies. The lag of axenic female flies but not male flies to forage on fruits is associated with lower oviposition by axenic flies, and mirrored by reduced food seeking observed in virgin females when compared to mated, gravid females. In contrast to foraging intensity being highly dependent on the microbiome, conventional and axenic flies of both sexes showed relatively consistent and similar fruit preferences in foraging and oviposition, with raspberries being preferred among the fruits tested. Collectively, this work highlights a clear sex-specific effect of the microbiome on foraging and locomotion behaviors in flies, an important first step toward identifying specific mechanisms that may drive the modulation of insect behavior by interactions between the host, the microbiome, and food.
Shifting microbiomes complement life stage transitions and diet of the bird parasite Philornis downsi from the Galapagos Islands
. ENVIRONMENTAL MICROBIOLOGY 2021
Domestication disconnects an animal from its natural environment and diet, imposing changes in the attendant microbial community. We examine these changes in Philornis downsi (Muscidae), an invasive parasitic fly of land birds in the Galapagos Islands. Using a 16S rDNA profiling approach we studied the microbiome of larvae and adults of wild and laboratory-reared populations. These populations diverged in their microbiomes, significantly more so in larval than in adult flies. In field-collected second-instar larvae, Klebsiella (70.3%) was the most abundant taxon, while in the laboratory Ignatzschineria and Providencia made up 89.2% of the community. In adults, Gilliamella and Dysgonomonas were key members of the core microbiome of field-derived females and males but had no or very low representation in the laboratory. Adult flies harbour sex-specific microbial consortia in their gut, as male core microbiomes were significantly dominated by Klebsiella. Thus, P. downsi microbiomes are dynamic and shift correspondingly with life cycle and diet. Sex-specific foraging behaviour of adult flies and nest conditions, which are absent in the laboratory, may contribute to shaping distinct larval, and adult male and female microbiomes. We discuss these findings in the context of microbe-host co-evolution and the implications for control measures.