Nutritional Status of Males and Sperm Transfer in the Scorpionfly Panorpa vulgaris (Mecoptera: Panorpidae)

Abstract

The results demonstrate that in the scorpionfly Panorpa vulgaris (Imhoff & Labram 1836), (a) the number of sperm transferred into the female's spermatheca during mating depends on the copulation duration; (b) differences in the nutritional status which have a significant effect on the mass of the salivary gland in males [MM] do not affect the number of sperm transferred during discrete copulation durations; (c) the number of sperm transferred by the MM during repeated copulations does not depend on the nutritional status; (d) a correlation between the number of sperm transferred during a first and second mating could not be demonstrated; (e) the nutritional status of females [FF] has no effect on the number of sperm transferred by the MM; (f) the loss of body mass of MM during a copulation of 200 min increases significantly with increasing condition index of their mates. These results indicate that within the scope of food availability tested in the present study it is not possible to decide clearly whether sperm supply is nutritionally limited. However, the great inter-male variation in the number of sperm transferred to the FF' spermatheca is consistent with the hypothesis that the sperm supply of some MM is limited. This study points up that the energetic cost of copulation of MM is not trivial.