Resting networks and personality predict attack speed in social spiders
Groups of social predators capture large prey items collectively, and their social interaction patterns may impact how quickly they can respond to time-sensitive predation opportunities. We investigated whether various organizational levels of resting interactions (individual, sub-group, group), observed at different intervals leading up to a collective prey attack, impacted the predation speed of colonies of the social spider Stegodyphus dumicola. We found that in adult spiders, overall group connectivity (average degree) increased group attack speed. However, this effect was detected only immediately before the predation event; connectivity between 2 and 4 days before prey capture had little impact on the collective dynamics. Significantly, lower social proximity of the group’s boldest individual to other group members (closeness centrality) immediately prior and 2 days before prey capture was associated with faster attack speeds. These results suggest that for adult spiders, the long-lasting effects of the boldest individual on the group’s attack dynamics are mediated by its role in the social network, and not only by its boldness. This suggests that behavioural traits and social network relationships should be considered together when defining keystone individuals in some contexts. By contrast, for subadult spiders, while the group maximum boldness was negatively correlated with latency to attack, no significant resting network predictors of latency to attack were found. Thus, separate behavioural mechanisms might play distinctive roles in determining collective outcomes at different developmental stages, timescales, and levels of social organization.
Certain animals in a group, such as leaders, may have a more important role than other group members in determining their collective behaviour. Often, these individuals are defined by their behavioural attributes, for example, being bolder than others. We show that in social spiders both the behavioural traits of the influential individual, and its interactions with other group members, shape its role in affecting how quickly the group collectively attacks prey.
KeywordsCollective behaviour Foraging Keystone individual Boldness Social network analysis Stegodyphus dumicola
We thank the South Africa Department of Tourism, Environment, and Conservation for providing permits for animal collection (FAUNA 1072/2013 and 1691/2015) and Colin Wright and James Lichtenstein for collecting spiders in the field. We further thank Arne Henningsen for the guidance on the ‘censReg’ R package.
ERH analysed the data and drafted the manuscript, NPW and JNP designed the study, BM, RG, CF, BW and NPW collected the data, and all authors contributed to the final version of the manuscript.
This work was supported by the National Science Foundation IOS grants 1456010 to NPW and 1455895 to JNP, and National Institutes of Health grant GM115509 to NPW and JNP.
- Bradoo B (1980) Feeding behaviour and recruitment display in the social spider Stegodyphus sarasinorum Karsch (Araneae, Eresidae). Tijdschr entomol 123:89-104.Google Scholar
- Burnham KP, Anderson DR (2002) Model selection and multimodel inference, 2nd edn. Springer, New YorkGoogle Scholar
- Fox J, Weisberg S (2011) An R companion to applied regression, Second edn. Sage, Thousand OaksGoogle Scholar
- Henningsen A (2017) censReg: Censored Regression (Tobit) Models. R package version 0.5 -26. https://cran.r-project.org/package=censReg
- Krause J, Ruxton GD (2002) Living in groups. Oxford University Press, USAGoogle Scholar
- Krause J, James R, Franks DW, Croft DP (2015) Animal social networks. Oxford University Press, USAGoogle Scholar
- Modlmeier AP, Laskowski KL, DeMarco AE, Coleman A, Zhao K, Brittingham HA, McDermott DR, Pruitt JN (2014c) Persistent social interactions beget more pronounced personalities in a desert-dwelling social spider. Biol Lett 10:20140419. https://doi.org/10.1098/rsbl.2014.0419 CrossRefPubMedPubMedCentralGoogle Scholar
- Pasquet A, Krafft B (1992) Cooperation and prey capture efficiency in a social spider, Anelosimus eximius (Araneae, Theridiidae). Ethology 90:121–133. https://doi.org/10.1111/j.1439-0310.1992.tb00826.x CrossRefGoogle Scholar
- Pinter-Wollman N, Fiore SM, Theraulaz G (2017a) The impact of architecture on collective behaviour. Nat Ecol Evol 1:0111. https://doi.org/10.1038/s41559-017-0111