Biology subjects

Inbar, S.

Publications and source records attributed to Inbar, S..

3 recordsLinked to original sources

bioRxiv2018

Incipient species or social polymorphism? Diversity in the desert ant Cataglyphis

Species are the fundamental units upon which evolutionary research is based. In insects, due to the high level of hybridization, the delimitation of such species can be challenging. The genus Cataglyphis presents a high level of diversification, making it an excellent model with which to study evolutionary paths. Israel appears to be a \"hot spot\" for recent speciation in this genus. Although previous studies have described multiple species of Cataglyphis in Israel, a recent genetic study has questioned the existence of some of these historically described species. The present study focuses on an apparent species complex that is distinguishable by its mitochondrial DNA (and therefore named mitotypes) but not by its nuclear DNA. Using a multi-method approach (genetics, chemistry and behavior), we show that these mitotypes also differ in their social structures and are readily distinguishable by their cuticular hydrocarbons profiles. While the different mitotypes are in general allopatric, at our study site they all coexist but nonetheless maintain the observed differences between them. This raises many evolutionary questions: Are these incipient species that have diverged with gene flow, or is this a case of social and chemical polymorphism that is maintained within a single species.

evolutionary biology↗

bioRxiv2018

Comparative study of population genomic approaches for mapping colony-level traits

Social insect colonies exhibit colony-level phenotypes such as social immunity and task coordination, which are the sum of individual phenotypes. Mapping the genetic basis of such phenotypes requires associating the colony-level phenotype with the genotypes in the colony. In this paper, we examine alternative approaches to DNA extraction, library construction and sequencing for genome wide association (GWAS) studies of colony-level traits. We evaluate the accuracy of allele frequency estimation in sequencing a pool of individuals (pool-seq) from each colony in either whole-genome sequencing or reduced representation genomic sequencing. Based on empirical measurement of the experimental noise in sequencing DNA pools, we show that whole-genome pool-seq is more accurate than reduced representation pool-seq. We evaluate the power of the alternative approaches for detecting quantitative trait loci (QTL) of colony-level traits by using simulations that account for an environmental effect on the phenotype. Our results can inform experimental designs and enable optimizing the power of GWAS depending on budget, availability of samples and research goals. We conclude that for a given budget, sequencing un-normalized pools of individuals from each colony achieves greater QTL detection power.

bioinformatics↗

bioRxiv2018

Split sex-ratio and variability in aggressive behavior in the ant Cataglyphis niger

In social insects, non-nestmates interactions are typically agonistic and many factors may influence the degree of exhibited aggression. Two of these factors are the physical proximity between nests and the chemical dissimilarity between colonies chemical signatures. We studied a population sample of 43 colonies of Cataglyphis niger ants distributed along a transect of [~]4KM. This geographic distribution allowed us to examine correlations of aggression levels with physical and chemical distances. Ants were collected before mating season, when sexuals (unmated gynes and drones) could be found in nests. In our sample, colonies had either gynes or drones but never both. The presence of sexuals, therefore, was another factor we took into account in our behavioral analyses. Workers from nests with sexuals were more aggressive towards conspecifics than workers from nests where sexuals were absent. We also found those workers to be more vigorously active towards colonies with greater chemical distances, while workers from nests without sexuals were indifferent to chemical distances. We therefore concluded that ants are able to detect differences in chemical dissimilarity, but their aggression levels are mainly determined by other mechanisms. A possible additional mechanism is associative learning and long term memory of the chemical signatures of neighboring colonies. Such learning is supported by our finding that aggression is higher towards neighboring nests, which is in line with the previously reported nasty neighbour effect in Cataglyphis ants. These results suggest that previous experience and learning of neural templates representing neighbors chemical cues is a stronger component than chemical dissimilarity in the mechanisms which determine aggression towards conspecifics in this species. We discuss possible explanations for the observed effect of the presence of sexuals on agonistic behavior and responsiveness to chemical distances.

evolutionary biology↗