Modalities of Feeding Behaviour in an Orb-Weaving Spider Zygiella X-Notata (Clerck) (Araneae: Araneidae)

Abstract

Prey capture and ingestion by the orb-weaving spider Zygiella x-notata have been studied in relation to prey type and to prey density (number of prey items presented/time unit). Whatever the type or the weight of a prey item (11 mg fly, 11 mg or 15 mg cricket larva), the pattern of prey capture did not vary. Ingestion rate did not vary during a meal when the prey was a fly, but this rate decreased with time when the prey was a cricket larva. This decrease was not due to satiation. When several prey items of the same type were placed simultaneously on a web, the spiders subdued them all, chose one of them (generally the first item) and then returned to its retreat to ingest it. A spider presented 3 crickets larvae at one-hour intervals, interrupted feeding on the first item when the second prey was presented. The second item was subdued more rapidly than the first one had been, but the spider left the second prey in the web and returned to its previous item. The third prey item was treated in the same manner as the second one. Spiders spent less time feeding on the first cricket larva in multi-prey tests, whatever the interval between prey arrivals, than on a cricket larva in single-prey test. On the other hand, no difference was found between the single-prey test and the multi-prey test when the prey were flies. In addition, whatever the prey type, quantities ingested (fresh weight) did not vary significantly between the single and multi-prey tests. Data presented here suggest that Zygiella x-notata can modify trade-offs obtained during prey item ingestion and that ingestion curves are good predictions of the quantity ingested in relation of time spent feeding.