Female genital morphology and sperm priority patterns in spiders (Araneae)

For spiders, gross female spermathecal morphology has been widely used as the major predictor of sperm priority pattern depending either upon taxonomic classification or on the number of ducts that connect with the spermathecae. In order to establish whether, or to what degree, the female reproductive tract follows a cul-de-sac (one duct connects to the spermatheca) or a conduit design (two ducts connect to the spermatheca at opposite ends) I present information on genital morphology of two haplogyne species (Pholcus phalangioides, Pholcidae; Dysdera erythrina, Dysderidae) and two entelegyne species (Nephila clavipes, Tetragnathidae; Pityohyphantes phrygianus, Linyphiidae). Predictions based on female anatomy and copulatory mechanisms are compared to available data on sperm utilization patterns. Female genital anatomy deviates markedly from the expected pattern in all cases. There are more than the two predicted types of sperm storage sites: sperm can either be stored in the bursa, or in spermathecae connected by two ducts that lie close together, or in multiple sperm stores of different morphology. If males are able to insert their genital structures as far as to the lumen of the female sperm storage organ, male manipulation of sperm masses stored from previous males are possible and changes in sperm priority patterns can be expected. Combined information on detailed female anatomy and copulatory mechanism do not suffice to make reliable predictions on the pattern of sperm priority. Possible reasons for this discrepancy are briefly outlined.