NUTRITIONAL-STATUS OF MALES AND SPERM TRANSFER IN THE SCORPIONFLY PANORPA-VULGARIS (MECOPTERA, PANORPIDAE)

The results demonstrate that in the scorpionfly Panorpa vulgaris (Imho ff & Labram 1836), (a) the number of sperm transferred into the female 's spermatheca during mating depends on the copulation duration; (b) d ifferences in the nutritional status which have a significant effect o n the mass of the salivary gland in males [MM] do not affect the numbe r of sperm transferred during discrete copulation durations; (c) the n umber of sperm transferred by the MM during repeated copulations does not depend on the nutritional status; (d) a correlation between the nu mber of sperm transferred during a first and second mating could not b e demonstrated; (e) the nutritional status of females [FF] has no effe ct 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 tha t within the scope of food availability tested in the present study it is not possible to decide clearly whether sperm supply is nutritional ly limited. However, the great inter-male variation in the number of s perm transferred to the FF' spermatheca is consistent with the hypothe sis that the sperm supply of some MM is limited. This study points up that the energetic cost of copulation of MM is not trivial.