Spatial learning affects thread tension control in orb-web spiders

Abstract

Although it is well known that spatial learning can be important in the biology of predators that actively move around in search for food, comparatively little is known about ways in which spatial learning might function in the strategies of sit-and-wait predators. In this study, Cyclosa octotuberculata, an orb-web spider that uses its legs to contract radial threads of its web to increase thread tension, was trained to capture prey in limited web sectors. After training, spiders that had captured prey in horizontal web sectors applied more tension on radial threads connected to horizontal sectors than spiders that had captured prey in vertical sectors. This result suggests that the effect of experience on C. octotuberculata's behaviour is not expressed in the way the trained spider responds to prey-derived stimuli and is instead expressed in behaviour by which the spider anticipates the likely direction from which prey will arrive in the future. This illustrates that learning can be important even when the predator remains in one location during foraging bouts.

Do cave orb spiders show unique behavioural adaptations to subterranean life? A review of the evidence

“…Orb spiders show a remarkable behavioural flexibility and modify their web-building and foraging behaviour in response to a wide range of internal and external factors including microclimatic conditions (Vollrath et al, 1997;Liao et al, 2009;Turner et al, 2011;Wu et al, 2013), prey capture experience (Pasquet et al, 1994;Heiling & Herberstein, 1999;Blamires, 2010), leg loss (Vollrath, 1987;Pasquet et al, 2011) and spatial constraints in the micro-habitat (Krink & Vollrath, 2000;Barrantes & Eberhard, 2012;Harmer et al, 2012;Hesselberg, 2013). Despite their relatively simple and small brains, they show impressive cognitive abilities (Hesselberg, 2015;Japyassu & Laland, 2017) including spatial learning of prey impacts (Nakata, 2013), alertness to web damage and faster repairs in windy conditions (Tew et al, 2015), simple numerosity (Rodríguez et al, 2015), and memories of previous web-building behaviour (Eberhard, 1988) and prey capture (Rodríguez & Gamboa, 2000;Rodríguez et al, 2013).…”

Evolution of brain elaboration

“…There is incidental evidence that the generalist scarab beetle Popillia japonica learns food source locations and returns to them repeatedly [89]. Finally, outside of the insects in the Chelicerata, the wandering spider Cupiennius salei has mushroom bodies that primarily receive visual input from the optic lobes [90], and the orb-web spider Cyclosa octotuberculata employs spatial learning to monitor more attentively the parts of the web that have previously been successful in capturing prey [91].…”

Exploration behaviour and behavioural flexibility in orb-web spiders: A review

“…Although webbuilding behaviour in spiders appears to be innate, this does not mean that they do not show learning in other aspects. The golden orb-web spider Nephila clavipes has recently been shown to remember the amount (and possibly the number) of recently caught and stored prey (Rodríguez et al, 2013;, the trashline orb-web spider Cyclosa octotuberculata learns the spatial location of recently caught prey in the web and selectively pulls radii in that sector (Nakata, 2013), and the missing sector orb-web spider Zygiella x-notata has been shown to rely on memory of the direction to its retreat when returning from excursions onto the web (LeGuelte, 1969). Evidence furthermore suggests that spiders rely on memory of distances travelled and the location of previously laid spiral threads during construction of the auxiliary and capture spirals (Eberhard, 1988a;Eberhard and Hesselberg, 2012).…”