Accessory gland proteins of males in the male-diphenic ant Cardiocondyla obscurior

Seminal fluid proteins are important agents in sperm competition and sexual conflict. In solitary insects, males and females may have different interests concerning the outcome of a mating episode, and males may use seminal fluid to manipulate the physiology and behaviour of the female against the latter's fitness interests. Less is known about the role of seminal fluids in social insects, where the interests of mating partners are more aligned because of life-long pair-bonding. In the male-diphenic ant Cardiocondyla obscurior, mating even with sterilized males appears to prolong the lifespan of queens, suggesting a positive role of seminal fluids. In the present study, using two approaches (two-dimensional gel electrophoresis/mass spectrometry and representational difference analysis), we analyze the seminal fluid and the male accessory glands of both winged and wingless males of C. obscurior. The results obtained reveal the presence of hundreds of proteins, of which proteases and protease inhibitors are also widespread in the seminal fluids of other insects