Predatory behavior of a social spider, Stegodyphus sarasinorum (Araneae: Eresidae): why attack first?

Stegodyphus sarasinorum Karsch is a Sri Lankan social spider that exhibits communal predation and feeding. A spider's feeding time is dependent on its position in the feeding sequence, with early feeders feeding longer than those arriving later. Feeding time per spider does not decrease with increasing group size when compared with a given feeding position, temporally speaking. The first spider to feed is the only individual whose feeding time is not shortened by conspecifics.