Rakosy, E. | bioRxiv Science

bioRxiv2025

Social plasticity in reproduction in female Drosophila melanogaster!

The expression of behaviours in individuals are not always fixed and may vary according to the specific environmental conditions encountered by an individual. There is significant evidence that male fruit flies, Drosophila melanogaster, have the capacity to adjust their courtship behaviours depending on the social environment they encounter; however, the extent of plasticity in behavioural responses by females have received much less scrutiny. In this study, we set out to determine whether the presence and/or the types of conspecifics an individual female encounters influences her subsequent reproductive behaviour and patterns of egg production. In our assay, we housed medium-sized adult virgin females in experimental social treatments; either in isolation, or with other conspecific females (that were either of large- or small- body size) to observe how the presence and/or type of social interactions altered later reproductive decisions and outcomes. While in some instances female flies behaved differently depending on their housing treatment, these responses were not particularly consistent between flies obtained from different populations, nor with previously described patterns. Potential contributing factors for these results, and their implications for the future study of female reproductive plasticity are discussed.

evolutionary biology↗

bioRxiv2024

On the use of kinship and familiarity associated social information in mediating Drosophila melanogaster oviposition decisions

Decisions where an individual lays their eggs are important, as the choice may affect their offsprings survival and lifetime reproductive success. Information produced by conspecifics can potentially be useful in decision-making as this "social information" may provide an energetically cheaper means of assessing oviposition site suitability rather than acquiring it personally. However, as not all public information may be equally beneficial, cues produced by kin may be especially valuable as they might signal suitable microenvironments, and are associated with other fitness advantages resulting from improved foraging success and/or a decreased risk of competition/cannibalism compared to sites where unrelated conspecifics are located. Using the fruit fly, Drosophila melanogaster, we explored whether public information use is associated with kin-based egg-laying decisions. Kinship is potentially recognized in several ways, including environmentally-associated proxy cues, so we explored whether there were biases in how focal females interacted with cues from conspecifics that differed in both genetic relatedness, and environmental "familiarity." In a series of inter-connected assays, we examined the behaviour of focal females that interacted with a choice of potential egg-laying substrates that differed in the manner of their prior conspecific exposure, and counted the offspring that eclosed from these different substrates. Sites that had exhibited cues produced by conspecific demonstrators were visited more, and yielded more focal offspring compared to unexposed substrates. Furthermore, patterns of bias in offspring production were consistent with ovipositing females exhibiting sensitivity to the kinship status of the prior substrates occupants. The basis of the kinship categorization by ovipositing females appears to be based on phenotypes that reflect true genetic relatedness, but the nature of the social information can be affected by other factors. These results further highlight the potential usefulness of D. melanogaster as a model to understand the evolution of social behaviour in the expression of decision-making.

evolutionary biology↗