Biology subjects

Lüpold, S.

Publications and source records attributed to Lüpold, S..

4 recordsLinked to original sources

bioRxiv2025

Male gut microbiome mediates post-mating sexual selection in Drosophila

When females mate with multiple males, sexual selection continues after mating and favors males with more competitive ejaculates. While these traits are physiologically costly and sensitive to internal state, the effects of the gut microbiome on male reproductive performance remains underexplored. Here, we tested how gut microbial communities influence sperm competition outcomes and the traits underpinning them by inoculating male Drosophila melanogaster with fully factorial synthetic consortia of five common commensal bacteria. We found highly context-dependent and non-additive microbial effects, along with two general patterns: Acetobacter-dominated microbiomes enhanced sperm transfer and increased paternity shares by 20-27% relative to germ-free males, whereas species richness strongly predicted sperm viability and female sperm storage. These results indicate that gut microbes contribute to multiple components of ejaculate performance through distinct pathways, potentially including nutrient provisioning for spermatogenesis, acetate-mediated energy metabolism, and microbe-dependent modulation of female sperm use. By integrating microbial ecology with reproductive biology, our findings establish the gut microbiome as an overlooked but fundamental modulator of sexually selected traits. This perspective helps clarify how non-genetic and community-based factors generate phenotypic variation under strong selection and provides a framework for future work on the mechanisms, transmission routes, and evolutionary consequences of host-microbe interactions in reproduction.

evolutionary biology↗

bioRxiv2024

Socio-ecological context modulates significance of territorial contest competition in Drosophila prolongata

The intensity and direction of sexual selection is intricately linked to the social and ecological context. Both operational sex ratios (OSRs) and population densities can affect the ability of males to monopolize resources and mates, and thus the form and intensity of sexual selection on them. Here, we studied how the mating system of the promiscuous and strongly sexually dimorphic fruit fly Drosophila prolongata responds to changes in the OSR and population density. We recorded groups of flies over five days and quantified territory occupancy, mating success, and competitive fertilization success. Although sexual selection was stronger under male-biased than even OSRs but unrelated to density, realized selection on morphological traits was higher under even OSRs and increased with density. Larger and more territorial males achieved both higher mating success and competitive fertilization success, but only under even OSRs. Our combined results also support a shift in the mating system from territorial contest competition to scramble competition under male-biased OSRs and potentially at low density, where there was no clear contribution of the measured traits to reproductive success. Our study emphasizes the limitations of traditional selection metrics and the role of the socio-ecological context in predicting adaptation to a changing environment. SignificanceMating systems are complex and dynamic, adapting to ongoing ecological change. Studies often assume that changes in the socio-ecological context alter the intensity of sexual selection on traits indicating individual fitness, but our work on Drosophila prolongata challenges this view. By manipulating operational sex ratio and population density, and jointly investigating territorial behavior and both pre- and post-mating reproductive success over several days, we reveal the plastic mating strategies in this fly. This dynamism underscores the limitations of static classifications and the importance of studying selection across diverse socio-ecological contexts. This broader perspective advances our understanding of the tight connections between environmental change, population demographics, and the evolutionary process.

evolutionary biology↗

bioRxiv2023

How hibernation in frogs drives brain and reproductive evolution in opposing directions

Environmental seasonality can promote the evolution of larger brains through cognitive and behavioral flexibility but can also hamper it when temporary food shortage is buffered by stored energy. Multiple hypotheses linking brain evolution with resource acquisition and allocation have been proposed for warm-blooded organisms, but it remains unclear how these extend to cold-blooded taxa whose metabolism is tightly linked to ambient temperature. Here, we integrated these hypotheses across frogs and toads in the context of varying brumation ( hibernation) durations and their environmental correlates. We showed that protracted brumation covaried negatively with brain size but positively with reproductive investment, likely in response to brumation-dependent changes in the socio-ecological context and associated selection on different tissues. Our results provide novel insights into resource allocation strategies and possible constraints in trait diversification, which may have important implications for the adaptability of species under sustained environmental change.

evolutionary biology↗

bioRxiv2019

Female x male and male x male interactions have limited influence on competitive fertilization in Drosophila melanogaster

How males and females contribute to joint reproductive success has been a long-standing question in sexual selection. Under postcopulatory sexual selection (PSS), paternity success is predicted to derive from complex interactions among females engaging in cryptic female choice and males engaging in sperm competition. Such interactions have been identified as potential sources of genetic variation in sexually selected traits but are also expected to inhibit trait diversification. To date, studies of interactions between females and competing males have focused almost exclusively on genotypes and not phenotypic variation in sexually selected traits. Here, we characterize within- and between-sex interactions in Drosophila melanogaster using isogenic lines with heritable variation in both male and female traits known to influence competitive fertilization. We found surprisingly few genotypic interaction effects on various stages of PSS such as female remating interval, copulation duration, sperm transfer, or sperm storage. Only the timing of female sperm ejection depended on female x male genotypic interactions. By contrast, several reproductive events, including sperm transfer, female sperm ejection and sperm storage, were explained by two- and three-way interactions among sex-specific phenotypes. We also documented complex interactions between the lengths of competing males sperm and the female seminal receptacle, which are known to have experienced rapid female-male co-diversification. Our results highlight the non-independence of sperm competition and cryptic female choice and demonstrate that complex interactions between the sexes do not limit the ability of multivariate systems to respond to directional sexual selection.\n\nSignificance statementFor species with internal fertilization and female promiscuity, postcopulatory sexual selection (PSS) is believed to depend, in part, on complex interactions between rival males and between the sexes. Although little investigated, clarifying such interactions is critical as they may limit the efficacy of PSS in the diversification of reproductive traits (e.g., ejaculate biochemistry and sperm, genitalia and female reproductive tract morphology). Here, we resolve how sex-specific traits and their interactions contribute to key reproductive events and outcomes related to competitive fertilization success, including traits known to have experienced rapid diversification. Our results provide novel insights into the operation and complexity of PSS and demonstrate that the processes of sperm competition and cryptic female choice are not independent selective forces.

evolutionary biology↗