Web inclination alters foraging success of a nocturnal predator

Abstract

In spider species, web inclination (vertical and horizontal webs) plays an important role in foraging success. However, these effects are poorly understood especially in such spiders that build both vertical and horizontal orb-webs. Recent studies have shown that spider species with horizontal orb-webs are specialized in preying aquatic insects emerging from the water. Females of a nocturnal orb-weaving spider, Larinioides cornutus, are able to build both vertical and horizontal orb-webs. Contrary to expectations, spiders which built horizontal orb-webs made higher expenditures in the form of sticky spirals and captured less prey in comparison with females in vertical webs. Moreover, horizontal webs were not closely related to water, as might have been expected given their potential function of catching aquatic insects, despite the probability of successful foraging was generally higher in webs placed closely to water stream. On the other hand, the probability of a web being destroyed was higher in vertical orb-webs, which may indicate that horizontal webs may be a compromise between more successful, but less lasting capture traps that would benefit from exposition during windless days and vice versa.

Intraspecific variation shapes community‐level behavioral responses to urbanization in spiders

“…Assuming spiders only have a finite amount of silk to allocate to webs, a small mesh width must be traded off against a smaller web capture surface (Eberhard 2013). Larger webs can intercept more prey, and are better at stopping prey (e.g., Prokop andGrygl akov a 2005, Harmer et al 2015). However, web investment was not constant across urbanization gradients: at the landscape scale, community-averaged CTL values increased with urbanization, an effect driven by ITV (Figs.…”

“…Changes in habitat structure, such as the replacement of complex natural vegetation (Parris ), which may have previously favored vertically flying insects (Bishop and Connolly ), by vertical buildings, may make urban environments less favorable to the building of horizontal webs. Moreover, although they may be more vulnerable to wind, vertical webs tend to be better at retaining intercepted prey (Prokop , Zschokke et al. ).…”

Differences in web features between two sympatric Leucauge species (Araneae: Tetragnathidae) suggest a trade-off in prey capture strategy

“…are in general more inclined, and vary through a larger range of angles than those of L. argyra. Horizontal orb webs are thought to be designed to capture aquatic insects (Kato et al 2003), as well as falling or jumping prey, while vertical webs are designed to capture primarily fast flying insects (Gregorič et al 2013), though conclusive data on this issue is lacking (Bishop & Connolly 1992;Prokop 2005). Thereby, we hypothesize that the webs of Leucauge sp.…”