SignificanceEphemeral diets such as carrion are high-quality resources that are susceptible to microbial spoilage. Carrion-feeding insects that breed on decaying carcasses must overcome challenges arising from competing microbes. Here we report that a carrion-feeding burying beetle preserves carcasses by regulating its microbial growth, resulting in changes in its biochemical properties including the reduction of toxic polyamines associated with putrefaction and nutrient loss. The beetle’s microbial symbionts form a biofilm-like matrix on carcasses, which is important for optimal larval development. The beetles and their microbiome thus coordinate a specialized adaptive strategy of carrion management, enabling them to preserve carrion quality and support larval growth in a challenging resource such as carrion.

Drosophila suzukii is threatening soft fruit production worldwide due to the females’ ability to pierce through the intact skin of ripe fruits and lay eggs inside. Larval consumption and the associated microbial infection cause rapid fruit degradation, thus drastic yield and economic loss. Cultivars that limit the proliferation of flies may be ideal to counter this pest; however, they have not yet been developed or identified. To search for potential breeding material, we investigated the rate of adult D. suzukii emergence from individual fruits (fly emergence) of 107 accessions of Fragaria species that had been exposed to egg-laying D. suzukii females. We found significant variation in fly emergence across strawberries, which correlated with accession and fruit diameter, and to a lesser extent with the strawberry species background. We identified accessions with significantly reduced fly emergence, not explained by their fruit diameter. These accessions constitute valuable breeding material for strawberry cultivars that limit D. suzukii spread.

If sexual signals are costly, covariance between signal expression and fitness is expected. Signal–fitness covariance is important, because it can contribute to the maintenance of genetic variation in signals that are under natural or sexual selection. Chemical signals, such as female sex pheromones in moths, have traditionally been assumed to be species-recognition signals, but their relationship with fitness is unclear. Here, we test whether chemical, conspecific mate finding signals covary with fitness in the moth Heliothis subflexa . Additionally, as moth signals are synthesized de novo every night, the maintenance of the signal can be costly. Therefore, we also hypothesized that fitness covaries with signal stability (i.e. lack of temporal intra-individual variation). We measured among- and within-individual variation in pheromone characteristics as well as fecundity, fertility and lifespan in two independent groups that differed in the time in between two pheromone samples. In both groups, we found fitness to be correlated with pheromone amount, composition and stability, supporting both our hypotheses. This study is, to our knowledge, the first to report a correlation between fitness and sex pheromone composition in moths, supporting evidence of condition-dependence and highlighting how signal–fitness covariance may contribute to heritable variation in chemical signals both among and within individuals.

If sexual signals are costly to produce or maintain, covariance between signal expression and fitness is expected. This signal-fitness covariance is important evolutionarily, because it can contribute to the maintenance of genetic variation in signal traits, despite selection from mate preferences. Chemical signals, such as moth sex pheromones, have traditionally been assumed to be stereotypical species-recognition signals, but their relationship with fitness is unclear. Here we test the hypothesis that for chemical signals that are primarily used for conspecific mate finding, there is covariation between signal properties and fitness in the noctuid moth Heliothis subflexa. Additionally, as moth signals are synthesized de novo every night throughout the female's reproductive life, the maintenance of the signal can be costly. Therefore, we also hypothesized that fitness covaries with signal stability (i.e. the lack of intra-individual variation over time). We measured among- and within-individual variation in pheromone amount and composition as well as fecundity, fertility, and fitness in two independent groups of females that differed in the time in between two consecutive pheromone samples. In both groups, we found reproductive success and longevity to be correlated with pheromone amount, composition, and stability, supporting both our hypotheses. This study is the first to report a correlation between fitness and sex pheromone composition in moths, solidifying previous indications of condition-dependent moth pheromones and highlighting how signal-fitness covariance may contribute to heritable variation in chemical signals both among and within individuals.