Bean weevils mating (Callosobruchus maculatus) Science Image

Ref: 80014484h



Bean weevils mating. Coloured scanning electron micrograph (SEM) of a pair of bean weevils (Callosobruchus maculatus) mating. The male's penis (yellow, centre right) has a tip covered in hard spines, which unfold during copulation. These penetrate the lining of the female's genital tract, leaving puncture wounds. Mating is costly for the female; if she copulates with more than one male, she incurs extensive damage and so dies early. The male's spiny penis therefore increases his chances of siring all of the female's eggs. It may also cause her to lay more eggs in total. Magnification x14 at 10cm wide