Biology subjects

Kohlmeier, P.

Publications and source records attributed to Kohlmeier, P..

5 recordsLinked to original sources

bioRxiv2024

Chemical mate choice copying in Drosophila melanogaster

Mate choice is a critical decision especially for females that requires time and energy to assess potential partners genetic quality. Consequently, in many species, females have evolved the ability to utilize social information by copying the mate choices of others, usually based on visual cues. However, many species, especially invertebrates, primarily rely on chemical not visual cues. Using chemical rather than visual cues provides several advantages such as not requiring active observation of copulations. Despite of that, empirical evidence for the existence of chemical mate choice copying is scarce. Using Drosophila melanogaster, we provide the first demonstration of chemical mate choice copying. Females exposed to a recently mated select the same male genotype as the teacher female mated with at a higher frequency than expected by chance. Chemical mate choice copying requires sensing both male and female cues, which might indicate that other females have chosen that male genotype. Our work suggests that females, in the presence of mated females, increase choosiness at the virgin stage, elevating sexual selection on male traits. This study provides novel evidence that exploiting social information is more prevalent in flies than previously assumed.

animal behavior and cognition↗

bioRxiv2024

Temperature-modulated maternal effects vary with offspring developmental stage in Drosophila melanogaster

An organisms phenotype has the potential to vary in response to environmental factors, allowing it to adjust to environmental fluctuations. Maternal effects on offspring phenotypes have been recognized as important contributors to this phenotypic plasticity, although the extent and duration of this contribution remain elusive. At more advanced developmental stages, offspring may be able to assess their current environment more accurately than at earlier developmental stages, and therefore their reliance on maternal effects may decline over time. This study investigates how the magnitude and direction of maternal effects change between early and late development using the fruit fly Drosophila melanogaster as a model. We employed a split brood design to disentangle the effects of maternal ambient temperature from the effects of offspring ambient temperature at the larval vs. the pupal or early adulthood stage. We subsequently measured offspring phenotypes such as heat shock and cold shock recovery times, survival, and developmental time. Maternal effects on these traits were often substantial during early offspring development, but these effects either diminished in magnitude or even changed direction as development progressed. In conclusion, our study reveals a dynamic shift in the magnitude and direction of maternal effects on offspring phenotypes in D. melanogaster, highlighting the interplay between maternal influence and offspring developmental stage in shaping adaptive responses to environmental variation.

ecology↗

bioRxiv2023

Cryptic female choice in response to male pheromones in Drosophila melanogaster

Females control the paternity of their offspring by selectively mating with males they perceive to be of high quality. In species where females mate with multiple males in succession, females may bias offspring paternity by favoring the sperm of one male over another, a process known as cryptic female choice (CFC). While evidence of CFC exists in multiple taxa, the mechanisms underlying this process have remained difficult to unravel. Understanding CFC requires demonstration of a female-driven post mating bias in sperm use and paternity, and a causal link between this bias and male cues. Here, we show that in the vinegar fly Drosophila melanogaster, mated females eject the ejaculate of their first mate faster when exposed to the pheromones of an attractive male than in the presence of an unattractive one. Using transgenic males expressing fluorescent sperm, we show that exposure to attractive males between mating causes twice-mated females to bias sperm storage towards the second male, affecting paternity. Using pheromonal bioassays in combination with genetic manipulation of sensory systems, we show that females modulate ejaculate ejection latency in response to male pheromones heptanal and 11-cis-Vaccenyl acetate (cVA) sensed via olfactory receptor neurons OR35a, Or22a, Or65a and OR67d, demonstrating that polyandrous females use male pheromonal cues to modulate ejaculate ejection timing. We provide the first demonstration to our knowledge of a CFC mechanism allowing a female to increase or decrease the share of paternity of her first mate depending on the sensing of the quality of potential mates in her environment. These findings showcase that paternity can be influenced by events that go beyond copulation and highlights the importance of post-copulatory sexual selection. One Sentence SummaryWe show that females bias sperm use and paternity towards specific males in response to male pheromones.

animal behavior and cognition↗

bioRxiv2021

Social modulation of oogenesis and egg-laying in Drosophila melanogaster

Being part of a group facilitates cooperation between group members, but also creates competition for limited resources. This conundrum is problematic for gravid females who benefit from being in a group, but whose future offspring may struggle for access to nutrition in larger groups. Females should thus modulate their reproductive output depending on their social context. Although social-context dependent modulation of reproduction is documented in a broad range of species, its underlying mechanisms and functions are poorly understood. In the fruit fly Drosophila melanogaster, females actively attract conspecifics to lay eggs on the same resources, generating groups in which individuals may cooperate or compete. The tractability of the genetics of this species allows dissecting the mechanisms underlying physiological adaptation to their social context. Here, we show that females produce eggs increasingly faster as group size increases. By laying eggs faster in group than alone, females appear to reduce competition between offspring and increase their likelihood of survival. In addition, females in a group lay their eggs during the light phase of the day, while isolated females lay them during the night. We show that responses to the presence of others are determined by vision through the motion detection pathway and that flies from any sex, mating status or species can trigger these responses. The mechanisms of this modulation of egg-laying by group is connected to a lifting of the inhibition of light on oogenesis and egg-laying by stimulating hormonal pathways involving juvenile hormone. Because modulation of reproduction by social context is a hallmark of animals with higher levels of sociality, our findings represent a protosocial mechanism in a species considered solitary that may have been the target of selection for the evolution of more complex social systems.

animal behavior and cognition↗

bioRxiv2018

Gene expression is stronger associated with behaviour than with age and fertility in ant workers

The ecological success of social insects is based on division of labour, not only between queens and workers, but also among workers. Whether a worker tends the brood or forages is strongly influenced by age, fertility and nutritional status, with brood carers being younger, more fecund and corpulent. Here, we experimentally disentangle behaviour from age and fertility in Temnothorax longispinosus ant workers and analyse how these parameters are linked to whole-body gene expression. Our transcriptome analysis reveals four times more genes associated with behaviour than with age and only few fertility-associated genes. Brood carers exhibited an upregulation of genes involved in lipid biosynthesis, whereas foragers invested in metabolism. Additional simulations revealed that the experimental disassociation of co-varying factors reduces transcriptomic noise, potentially explaining discrepancies between transcriptomic studies on worker behaviour in other social insects. Our study highlights the influence of nutritional status on task choice in ant workers.

evolutionary biology↗