The foraging behaviours of Argyrodes antipodiana (Theridiidae), a kleptoparasitic spider from New Zealand

Abstract

The foraging behaviours of Argyrodes antipodiana (O.P. Cambridge) were observed in the laboratory and in nature. A. antipodiana is a kleptoparasitic spider primarily dependent on one host, an orb web-building spider, Araneus pustulosa. To exploit the host, A. antipodiana builds a support web on which it relies heavily. The support web is attached to the host’s web and enables A. antipodiana, without being detected, to swing to safety with stolen food bundles, remove gleaned insects, and feed with the host.

Although the host provides food for A. Antipodiana, it is also a potential predator which the kleptoparasite must avoid. Here the support web is again invaluable as it is a structure into which A. antipodiana can swing if threatened by the host.

Besides being kleptoparasitic, A. antipodiana is also araneophagic (i.e., it eats spiders). A. antipodiana preys on the host when it is vulnerable during moulting and also captures the host’s spiderlings by using aggressive mimicry.

A. bantipodiana may also obtain food without using the host. It builds a sticky space web, unattached to a host’s web, with which it can catch flies, albeit inefficiently.

The foraging behaviours of A. antipodiana are compared with those of other studied species of Argyrodes, and speculations concerning phylogenetic relationships between behavioural groups within the genus Argyrodes are presented.

Keywords:

• spider
• kleptoparasitism
• araneophagy
• Argyrodes antipodiana
• foraging
• behaviour
• evolution