Memory of prey larders in golden orb-web spiders, Nephila clavipes (Araneae: Nephilidae)

Nephila clavipes spiders accumulate prey larders on their webs. We conducted a field experiment to ask if the spiders search for larders that have been pilfered (experimentally mimicking the potential effect of kleptoparasites), and to ask if the spiders vary their search efforts according to the size of the larder. All spiders searched for larders removed from their web, and spiders that lost larger larders (i.e., consisting of more prey items) searched for longer intervals. We thus suggest that N. clavipes form memories of the size of the larders they have accumulated, and that they use those memories to regulate recovery efforts when the larders are pilfered. The content of those memories may include discrete prey counts or the accumulation of a continuous variable correlated with counts, such as the total mass of captured prey. We discuss the adaptive significance of this ability in the framework of costs related to kleptoparasites and the ecology of food hoarding.