Kleptoparasitic spiders of the subfamily Argyrodinae: a special case of behavioural plasticity

Throughout this book we have seen numerous examples of the flexible nature of spider behaviour. This includes flexibility in silk and web production and design; foraging, anti-predatory and deceptive behaviour; and sociality and courtship behaviour. We have also seen how behavioural plasticity and learning enhances the flexibility of these different behaviours. In this chapter we will look at a subfamily of spiders, Argyrodinae (Theridiidae), to see how all these forms of flexibility contribute to the success of this group. Argyrodinae are by no means the most successful group of spiders, nor are they likely to be the most intelligent (if it were possible to measure such a thing in spiders, that award would undoubtedly go to individuals in the Portia genus) but they are an interesting group of spiders that illustrate many of the concepts discussed in the book, and they also show some unusual takes on common themes. Introduction. The subfamily Argyrodinae, which contains over 200 species, is well known for its association with the webs of other spiders, and the range of foraging techniques this group uses to exploit other spiders. For example, there are species that glean insects off the edge of the web (e.g. Hénaut, 2000, Kullmann, 1959), eat the silk from the web (e.g. Cangialosi, 1991, Grostal and Walter, 1997, Kerr and Quenga, 2004, Miyashita et al., 2004), steal food bundles caught and wrapped by the host spider (e.g. Hénaut et al., 2007, Vollrath, 1984, Whitehouse, 1997a), attack the host while it is moulting (Cangialosi, 1990, Tanaka, 1984, Whitehouse, 1986) and actively prey on the host or its young (Eberhard, 1979, Larcher and Wise, 1985, Smith Trail, 1980) by either by throwing a sticky thread (Eberhard, 1979, Whitehouse, 1987a) or by lunging at them (Whitehouse, 1986).