Leg autotomy in Pholcus beijingensis (Araneae: Pholcidae)

The occurrence and effects of appendage loss on fitness in spider Pholcus beijingensis (Araneae: Pholcidae) were studied. Leg loss was common in natural populations, with 20% of individuals surveyed were missing at least one leg, most commonly one of the anterior pair. The frequency of occurrence varied from month to month. Our results found that the first pair of legs may not be critical to the survival of pholcid spiders. In laboratory experiment, the individuals who lost leg(s) did not regenerate. Furthermore, juveniles with appendage loss had significantly reduced growth rates. Leg autotomy may reduce fitness of spiders, but it can avoid more significant loss of fitness such as death. Leg autotomy is likely a bet-hedging strategy for pholcid spiders [Acta Zoologica Sinica 54（6）：998–1004，2008].