In the February issue of Ecology Letters , Moret and Schmid-Hempel at the Swiss Federal Institute of Technology of Zurich, report a study that tested for this possibility by experimentally activating the immune response of individual workers in colonies of the bumblebee Bombus terrestris. This induction resulted, in combination with environmental conditions, in a reduction of fitness of the social unity and a collective response towards earlier reproduction. As both phenomena are expressed at the level of the colony, the result suggests that key elements of the use of immune defence have been maintained through the evolutionary transition to sociality.
Ecology Letters