Lateralized antennal control of aggression and sex differences in red mason bees, Osmia bicornis.

Comparison of lateralization in social and non-social bees tests the hypothesis that population-level, directional asymmetry has evolved as an adjunct to social behaviour. Previous research has supported this hypothesis: directional bias of antennal use in responding to odours and learning to associate odours with a food reward is absent in species that feed individually, such as mason bees, whereas it is clearly present in eusocial honeybees and stingless bees. Here we report that, when mason bees engage in agonistic interactions, a species-typical interactive behaviour, they do exhibit a directional bias according to which antenna is available to be used. Aggression was significantly higher in dyads using only their left antennae (LL) than it was in those using only their right antennae (RR). This asymmetry was found in both males and females but it was stronger in females. LL dyads of a male and a female spent significantly more time together than did other dyadic combinations. No asymmetry was present in non-aggressive contacts, latency to first contact or body wiping. Hence, population-level lateralization is present only for social interactions common and frequent in the species' natural behaviour. This leads to a refinement of the hypothesis linking directional lateralization to social behaviour.

Combining experimental evolution with next-generation sequencing: a powerful tool to study adaptation from standing genetic variation.

Evolve and resequence (E&R) is a new approach to investigate the genomic responses to selection during experimental evolution. By using whole genome sequencing of pools of individuals (Pool-Seq), this method can identify selected variants in controlled and replicable experimental settings. Reviewing the current state of the field, we show that E&R can be powerful enough to identify causative genes and possibly even single-nucleotide polymorphisms. We also discuss how the experimental design and the complexity of the trait could result in a large number of false positive candidates. We suggest experimental and analytical strategies to maximize the power of E&R to uncover the genotype-phenotype link and serve as an important research tool for a broad range of evolutionary questions.