DOES LONG-TERM STORAGE OF SPERMATOZOA OCCUR IN THE ADDER (VIPERA-BERUS)

In the adder (Vipera berus) multiple inseminations during the spring m ating season have been demonstrated. with fertilization taking place s everal weeks after mating activities have ceased. Subsequent sperm com petition in the female reproductive tract can result in within-season mixed paternity. Prolonged sperm storage between mating seasons has be en suggested as another mechanism of sperm competition in the adder. C ompetition between new and old spermatozoa would obstruct efforts to r eveal reproductive strategies that correlate observed behaviour to pat ernity in natural populations. In the present study, controlled breedi ng experiments with adders were performed and DNA fingerprinting was u sed to determine paternity among all offspring of a total of 15 litter s. The offspring of II large females, that had most probably also mate d in a previous season. were sired exclusively by enclosure males. Thi s result and earlier empirical data support the hypothesis that long-t erm sperm storage, over one or several reproductive cycles, does not o ccur in the adder.