Web decoration polymorphism in Argiope Audouin, 1826 (Araneidae) spiders: ontogenetic and interspecific variation

Abstract

Spiders in the genus Argiope commonly include curious silk structures, termed web decorations or stabilimenta in their webs. Whilst interesting ontogenetic and interspecific variation in both the form and frequency of web decorations has been documented, to our knowledge this is the first study to compare this variation across a number of decorating species. Here we show that two sympatric species A. picta and A. aetherea construct different forms of web decorations as adults and that A. picta decorates at a higher frequency than A. aetherea. Furthermore, this difference in decoration frequency may be related to the different decoration forms (linear or cruciate) across this genus. We also show that native bees responded significantly more quickly to cruciate decorations than to linear decorations. Here we argue that consideration of the different decoration forms and the frequency at which spiders adorn their webs may help illuminate possible context‐dependent functions for these curious structures.

Keywords:

• Anti‐predator behaviour
• Argiope
• prey capture
• stabilimenta
• web decorations

Acknowledgements

We thank Greg Holwell for assistance in field surveys and collection. One anonymous referee provided useful comments. The Australian Research Council and Macquarie University (grants to M.E.H.) and an Australian Postgraduate Award (M.J.B.) supported our work.