par Thangasamy, Needhi 
Promoteur Dapporto, Leonardo
Co-Promoteur Cini, Alessandro
Publication Non publié, 2022-08-30
Promoteur Dapporto, Leonardo
Co-Promoteur Cini, Alessandro
Publication Non publié, 2022-08-30
Mémoire
| Résumé : | The study of gregarious organisms is essential to understanding the various factors that lead to the major evolutionary transition from solitary to group living species. The phylogenetic origin of animal aggregations has been widely discussed and debated since the many advantages of group-living are countered by the increased risks of conspicuousness, competition, inbreeding and disease. In 1971, Hamilton proposed the selfish herd (SH) theory as a potential explanation, where he argued that aggregative tendencies arose from selfish cover seeking individuals attempting to place their conspecifics between themselves and an approaching predator. While this is well studied in groups of vertebrates and other arthropods, there is limited and scattered empirical evidence regarding the occurrence of the SH effect in insects. Here we review all available entomological literature that mention the SH effect, and further explore research biases, knowledge gaps, and criticisms. Using pre-collected photographs and data from Malaysia, we also tried to test some of the SH predictions in clustered colonies of the tropical eusocial wasp (Liostenogaster vechti). Our findings show that non-edge nests benefit from increased productivity but also face greater frequencies of intraspecific competition, both of which are consistent with the SH theory. No such positional differences were observed for nest damage and brood survival though. The results of both the review and the field test offer important insights on potential future directions for SH studies, and also reveal the need to revise how we conceptualize and test selfish behaviour in insects. |
