Novel or highly modified genes play a major role in the development of the different castes within ant colonies. Evolutionary biologists at Johannes Gutenberg University Mainz (JGU) came to this conclusion in a recent gene expression study. Dr. Barbara Feldmeyer and her colleagues at the JGU Institute of Zoology studied the question how the different female castes arise. An ant colony generally consists of a queen and the workers. Moreover, workers can differ depending on the task they perform, such as brood care, foraging, or nest defense. This behavioral specialization may be accompanied by morphological and physiological differences. Queens, solely responsible for reproduction, can live up to 30 years while workers have life spans ranging from a few months to several years. In some species there are also soldier ants, which can weigh up to 100 times more than their worker sisters who take care of the brood.
Interestingly, the divergent phenotypic traits of queens and workers develop from the same genetic background; the different phenotypic trajectories are determined by the food larvae receive during development. Usually the queen is the sole reproductive individual in a nest but if she dies or is removed, some brood-care workers will develop their ovaries and begin to reproduce. It was this phenomenon that the Mainz scientists exploited in order to induce fertility in brood-care workers of the Temnothorax longispinosus ant species. This allowed the comparison of these fertile workers with infertile brood-carers, foragers, and the queens to determine the expression of genes causing the enormous variations in behavior, fertility, and life span.
"We have here the ideal model system to study polyphenism, which describes the situation in which one and the same genotype gives rise to phenotypes that differ in terms of individual morphology, behavior, and life history," said Dr. Barbara Feldmeyer. Each sample used for RNA sequencing
|Contact: Professor Susanne Foitzik|
Johannes Gutenberg Universitaet Mainz