Arachnologische Mitteilungen 58

100 O. M. Drisya-Mohan, N. A. Kashmeera & A. V. Sudhikumar Discussion Cooperative social spiders share a communal web and nest where the colonies can extend to group sizes from a few to thousands of individuals (Whitehouse & Lubin 2005). In the case of S. sarasinorum, even those who did not participate in the actual prey capture activities may join in the feeding and feed communally (Bradoo 1980). Among the 30 nests analyzed on the Christ College campus, we found that the most abundant prey of S. sarasinorum was the order Coleoptera (beetles).The second most abundant prey is Orthoptera, which includes grasshoppers. This finding is similar to Majer et al. (2018), where this social Stegodyphus mostly captured the prey from the taxa Coleoptera, Diptera and Hymenoptera and the less abundant prey taxa included Isoptera, Lepidoptera and Or- thoptera. Our results confirms that social Stegodyphus species forage in relation to available prey rather than on specific prey types. Pasquet & Krafft (1992) studied the cooperative behav- iour in another social spider Anelosimus eximius. This spider captured a large proportion of Orthoptera and Lepidoptera. Cooperative prey capture behaviour may function to cap- ture prey that is much larger than the body size of the spider predator (Nentwig 1985, Yip et al. 2008), with several indi- viduals within a group feeding on the prey item simultane- ously. Anelosimus eximius captures larger prey than spiders of similar size but with a less complex organization (Nentwig & Christenson 1986), and also other social Stegodyphus increase dietary niche through cooperative prey capture (Majer et al. 2018).This is also confirmed by our result that S. sarasinorum can capture larger sized prey (up to 50 mm) than its own body size (7.5 ± 0.07 mm). Group living and cooperative foraging are hypothesized to expand dietary niche to meet the incre- asing resource demand of the group and reduce competition, and risk of conflict over the distribution of resources (Ulbrich & Henschel 1999, Majer et al. 2018). The cribellate web sheets formed by S. sarasinorum act as an excellent trap for large insects like locusts, grasshoppers, wasps, beetles, dragonflies, moths and many other kinds of Coleoptera and Hymenoptera, etc. (Bradoo 1972). Once the- Fig. 2: Immobilization time (minutes) and recruitment time (minutes) of grasshoppers and beetles during the two periods Active period Immobilization time in minutes 40 35 30 25 20 15 10 5 0 0 10 20 30 40 Number of test Grasshopper Beetle Passive period Recruitment time in minutes 45 40 35 30 25 20 15 10 5 0 0 10 20 30 40 Number of test Grasshopper Beetle Active period Recruitment time in minutes 35 30 25 20 15 10 5 0 0 10 20 30 40 Number of test Grasshopper Beetle Immobilization time in minutes 70 60 50 40 30 20 10 0 0 10 20 30 40 Number of test Grasshopper Beetle Passive period