Sexual behaviour of the Mediterranean fruit fly (Diptera: Tephritidae): the influence of female size on mate choice

Most studies of the sexual behaviour of the Mediterranean fruit fly Ceratitis capitata Wiedemann 1824 (Tephritidae: Ceratitidini) have concentrated on determining which male characteristics influence their copulatory success and little is known about the female's influence on this process. The present study investigated the influence of female size on the selection of different sized males. The experiments were undertaken using a colony maintained under laboratory conditions for 15 years with the frequent introduction of wild flies. Adults of different sizes ('larger' and 'smaller') were obtained by providing two groups of larvae with different concentrations of protein (7.0 g of yeast/100 ml of water = high protein content, 3.0 g of yeast/100 ml of water = low protein content). Mate choice tests were performed in a laboratory environment as well as in a field cage, with larger or smaller females being simultaneously exposed to larger and smaller males. The results indicated that in both the laboratory and field cage tests both larger and smaller females preferred mating with larger males. The data is discussed in terms of the possible advantages to the females associated with their choice of males with large body sizes.