Project description:BackgroundUnder strong sexual selection, certain species evolve distinct intrasexual, alternative reproductive tactics (ARTs). In many cases, ARTs can be viewed as environmentally-cued threshold traits, such that ARTs coexist if their relative fitness alternates over the environmental cue gradient. Surprisingly, the chemical ecology of ARTs has been underexplored in this context. To our knowledge, no prior study has directly quantified pheromone production for ARTs in a male-polymorphic species. Here, we used the bulb mite-in which males are either armed fighters that kill conspecifics, or unarmed scramblers (which have occasionally been observed to induce mating behavior in other males)-as a model system to gain insight into the role of pheromones in the evolutionary maintenance of ARTs. Given that scramblers forgo investment into weaponry, we tested whether scramblers produce higher quantities of the putative female sex-pheromone α-acaridial than fighters, which would improve the fitness of the scrambler phenotype through female mimicry by allowing avoidance of aggression from competitors. To this end, we sampled mites from a rich and a poor nutritional environment and quantified their production of α-acaridial through gas chromatography analysis.ResultsWe found a positive relationship between pheromone production and body size, but males exhibited a steeper slope in pheromone production with increasing size than females. Females exhibited a higher average pheromone production than males. We found no significant difference in slope of pheromone production over body size between fighters and scramblers. However, scramblers reached larger body sizes and higher pheromone production than fighters, providing some evidence for a potential female mimic strategy adopted by large scramblers. Pheromone production was significantly higher in mites from the rich nutritional environment than the poor environment.ConclusionFurther elucidation of pheromone functionality in bulb mites, and additional inter- and intrasexual comparisons of pheromone profiles are needed to determine if the observed intersexual and intrasexual differences in pheromone production are adaptive, if they are a by-product of allometric scaling, or diet-mediated pheromone production under weak selection. We argue chemical ecology offers a novel perspective for research on ARTs and other complex life-history traits.
Project description:Life history traits play an important role in population dynamics and correlate, both positively and negatively, with dispersal in a wide range of taxa. Most invertebrate studies on trade-offs between life history traits and dispersal have focused on dispersal via flight, yet much less is known about how life history trade-offs influence species that disperse by other means. In this study, we identify effects of investing in dispersal morphology (dispersal expression) on life history traits in the male dimorphic bulb mite (Rhizoglyphus robini). This species has a facultative juvenile life stage (deutonymph) during which individuals can disperse by phoresy. Further, adult males are either fighters (which kill other mites) or benign scramblers. Here, in an experiment, we investigate the effects of investing in dispersal on size at maturity, sex and male morph ratio, and female lifetime reproductive success. We show that life history traits correlate negatively with the expression of the dispersal stage. Remarkably, all males that expressed the dispersal life stage developed into competitive fighters and none into scramblers. This suggests that alternative, male reproductive strategies and dispersal should not be viewed in isolation but considered concurrently.
| S-EPMC4556651 | biostudies-literature
Project description:Transcriptomes of Aspergillus niger conidia cultivated at different temperatures
| PRJNA981668 | ENA
Project description:Fermentation at different temperatures
Project description:Identification of microRNA expressed in Arabidopsis plants grown at different ambient CO2 concentrations and different ambient temperatures
2013-12-22 | GSE36934 | GEO
Project description:Replicated community assembly at different temperatures