Description du projet
Décrypter le mécanisme de stérilité chez les fourmis
Un phénomène couramment observé et inexpliqué dans les colonies d’insectes sociaux est celui de la stérilité des castes d’ouvrières. La perte de la capacité à se reproduire a été expliquée jusqu’à présent soit par l’hypothèse de la monogamie dominante, c’est-à-dire la transmission indirecte des gènes, soit par l’hypothèse de l’application de la coopération par le maintien de l’ordre. Le projet AntPolice, financé par l’UE, étudiera les circonstances qui conditionnent la stérilité des fourmis ouvrières et conclura sur l’hypothèse la plus probable. Cette étude sera menée à travers une analyse phylogénétique comparative pionnière portant sur des centaines d’espèces de fourmis et de nouvelles expériences en laboratoire sur la fourmi socialement polymorphe Formica exsecta.
Objectif
The sterile worker castes found in the colonies of social insects are often cited as archetypal examples of altruism in nature. The challenge is to explain why losing the ability to reproduce has evolved as a superior strategy for transmitting genes into future generations. The leading explanation for the evolution of worker sterility is the monogamy hypothesis. The idea is that workers don't need to reproduce because they can transmit their genes indirectly by improving the reproductive success of the queen, who carries the same genes. For this to work, the queen should be monogamously mated, ensuring workers are raising full siblings, the genetic equivalent of their own young (r = 0.5). There has been no appropriate test of this hypothesis, however, and an alternative hypothesis, that worker sterility evolved via the enforcement of cooperation by policing, has not been ruled out. According to the policing hypothesis, workers suppress each other's reproduction by eating each other’s eggs or through aggression, leading to sterility through evolutionary time. Crucially, policing is predicted to evolve when relatedness is low, in contrast to the monogamy hypothesis.
Here, I propose an interdisciplinary approach that combines a cutting-edge phylogenetic comparative analysis across ~500 ant species with novel lab-based experiments on the socially polymorphic ant, Formica exsecta, to test between the low and high relatedness evolutionary pathways to worker sterility. Contrary to common belief, workers in most ant species can lay eggs due to their haplodiploid sex determination system, making them an ideal system for answering this question. This project will fill a crucial gap in our knowledge of how complex life on Earth evolved and potentially overturn the long-held hypothesis that high relatedness is the only route to cooperation.
Champ scientifique
Programme(s)
- HORIZON.1.2 - Marie Skłodowska-Curie Actions (MSCA) Main Programme
Régime de financement
HORIZON-TMA-MSCA-PF-EF - HORIZON TMA MSCA Postdoctoral Fellowships - European FellowshipsCoordinateur
90014 Oulu
Finlande