Positioning at the hub: does it matter on which side of the web orb-web spiders sit?

Abstract

Two orb-web spider species, one diurnal and one nocturnal, were studied and shown to be highly flexible in their behaviour. Flexibility is discussed in relation to improving capture success and avoiding predation. Although earlier studies have revealed that spiders modify web design and web orientation according to light and wind direction, here we show that orb-web spiders can further respond to light and wind direction by choosing a side of the web to reside on. The diurnal species, Argiope keyserlingi, tended to orient its dorsal side into vegetation gaps and towards light, whereas the nocturnal species, Larinioides sclopetarius, tended to expose its dorsal side into the oncoming wind. While orientation on the web had little affect on prey capture success, in A. keyserlingi, orientation into vegetation gaps may reduce attacks by praying mantids which approach the spiders by walking along the vegetation surrounding the web. In contrast, exposing the dorsal side into the wind may increase stability on the web for L. sclopetarius, preventing the spiders from being dislodged from the webs by strong gusty wind.