Biology subjects

Van Meyel, S.

Publications and source records attributed to Van Meyel, S..

3 recordsLinked to original sources

bioRxiv2026

Gregariousness can promote invasion success of pest insects while higher environmental heterogeneity decreases it

Climate change and environmental homogenization are expected to facilitate the expansion of many forest pest insect species and increase the vulnerability of forest ecosystems to insect outbreaks. At present, we lack empirical data on how the antipredator defence traits of pest insects interact with the local environmental conditions and shape outbreak risk. Here we study this and ask 1) how the antipredator defence strategy of pest insects shapes survival under naturally varying predator community, and 2) how is predation risk shaped by the diversity and structure of forests? We tested these questions by conducting a field predation experiment with artificial prey system (prey items made from edible dough) where we manipulated the gregariousness, unpalatability and defensive colouration of prey and tested their effects on prey survival. Additionally, we measured environmental variables and invertebrate predator community structure along the prey transects to analyse how they shape overall predation risk. Our results show that the predation risk was always lowest for gregarious prey irrespective of other defence strategies. Furthermore, our results indicate that predation pressure was lower in more homogenously structured forest areas or areas with a weak quality deadwood continuum in comparison to locations with more natural state forests and good quality deadwood continuum. Altogether, our results suggest that gregariousness can facilitate pest insects to form outbreaks by increasing their survival against generalist predators. However, by maintaining higher heterogeneity in forests, it is possible to ensure higher predation pressure to regulate their population growth.

ecology↗

bioRxiv2025

Group size dependent selection for cooperation versus freeloading in collective chemical defence

Individuals can cooperate in groups to achieve greater fitness, but the contribution of each individual to the collective good may depend on group size and on strategies employed by other members. How environmental contexts influence selection for cooperation is currently poorly understood and lacks experimental evidence from systems exhibiting behavioural plasticity in collective acts. This study investigates group size dependent selection on collective chemical defence in a gregarious pine sawfly (Neodiprion sertifer). Larvae perform chemical defence by secreting a costly deterrent fluid while adopting a U-posture. By manipulating group size and the individuals ability to deploy the defensive fluid for the collective good, we show that survival against predation is higher in cooperative groups and that the benefits gained via collective defence are more pronounced in smaller groups. As predicted by theory, individuals participate less in collective defence in larger groups than in smaller ones. This lower contribution is not attributed to higher life-history costs from increased resource competition. Altogether, these results suggest that selection for cooperation in public goods is group size dependent, promoting cooperation in smaller groups whereas the relative fitness of freeloaders is higher in larger groups.

evolutionary biology↗

bioRxiv2020

Alteration of gut microbiota with rifampicin does not impair maternal care in the European earwig

AO_SCPLOWBSTRACTC_SCPLOWThe microbes residing within the gut of an animal host often increase their own fitness by modifying their hosts physiological, reproductive, and behavioural functions. Whereas recent studies suggest that they may also shape host sociality and therefore have critical effects on animal social evolution, the impact of the gut microbiota on maternal care remains unexplored. This is surprising, as this behaviour is widespread among animals, often determines the fitness of both juveniles and parents, and is essential in the evolution of complex animal societies. Here, we tested whether life-long alterations of the gut microbiota with rifampicin - a broad-spectrum antibiotic - impair pre- and post-hatching maternal care in the European earwig. Our results first confirm that rifampicin altered the mothers gut microbial communities and indicate that the composition of the gut microbiota differs before and after egg care. Contrary to our predictions, however, the rifampicin-induced alterations of the gut microbiota did not modify pre- or post-hatching care. Independent of maternal care, rifampicin increased the females feces production and resulted in lighter eggs and juveniles. By contrast, rifampicin altered none of the other 21 physiological, reproductive and longevity traits measured over the 300 days of a females lifetime. Overall, these findings reveal that altering the gut microbiota with a large spectrum antibiotic such as rifampicin does not necessarily affect host sociality. They also emphasize that not all animals have evolved a co-dependence with their microbiota and call for caution when generalizing the central role of gut microbes in host biology.

evolutionary biology↗