DISSERTATION RESEARCH: Matricide in eusocial wasps: adaptive hypotheses and informational constraints

Cornell University, Ithaca NY

Investigators

Abstract

One of the goals of behavioral biologists is to understand why sometimes there is close cooperation among in animal societies and why at other times there is intense conflict. This project will help us understand the shifting balance between cooperation and conflict by investigating a striking switch from strong cooperation to stunning conflict inside the nests of a common species of yellow jacket wasp called Dolichovespula arenaria. The nests of these wasps are the familiar grey, paper structures about the size of a soccer ball that appear in trees and on buildings. Inside each one lives a family of wasps that includes a mother wasp (the queen) and dozens of her daughters and sons. Most of the time, the daughter wasps cooperate with their mother, helping her by building the nest, defending it, collecting food, and helping rear the queen's offspring. But late in the summer, one of the daughter wasps will suddenly sting and kill the mother wasp and then start laying eggs herself. How such a dramatic switch from cooperation to conflict can have evolved is the puzzle that this study addresses. Using novel video recording methods that enable us to carefully monitor the situation inside each colony at the time of the matricide, the PI will test several hypotheses for how it can actually benefit a daughter wasp to kill her mother. One possibility is that the mother wasp has lost her fertility, in which case the workers have little to lose and much to gain by killing their mother and taking over the nest. This work will be deepen our understanding of the biological forces that influence cooperation and conflict, and this is a matter of great relevance to human society.