Geographic range has long been noted to be associated with many organismic and ecological traits such as body size and species richness. However, much less is known about whether and how ecological variation across latitudinal gradients reflects behavioral variation. Ant colonies may also show behavioral variation, and Temnothorax rugatulus show a colony-level behavioral syndrome that seems to reflect risk tolerance across their North American range. While it is presumed that this pattern is the result of adaptation to local environmental conditions, which ecological factors are driving this variation are unknown. Here, we test if colony risk tolerance is affected by competition, predation, resource availability, or environmental stress at each site. Our results show that increased competition, specifically for nest sites, as well as increased spatial clustering of colonies predicts higher risk tolerance. Additionally, the spatial clustering of colonies influences the structure of the risk-taking syndrome, i.e., which colony-level behaviors are correlated and how strongly. This emphasizes the need for understanding large-scale geographic variation in behavior, as it may explain how ecological factors drive the evolution and maintenance of intraspecific behavioral variation across populations.
Aggression Foraging behavior Environmental effects Local adaptation Behavioral syndrome Social insects
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We would like to thank the Dornhaus lab, Stephen Pratt and two anonymous reviewers for helpful feedback on the manuscript, Daniel Charbonneau for advice and feedback on the data analysis, Min Shin and Hoan Nguyen for their development of the optic flow algorithm, as well as NSF (grants no. IOS-1045239 and DBI-1262292 to AD).
Supplemental Figure 1All of the models tested in the stepwise model selection process and the associated AIC value of each model. The final model selected resulted in the percentage of nest sites occupied and the clustering index as the predictive variables with an AIC score of -146.9. (JPEG 60 kb)
Biro PA, Abrahams MV, Post JR, Parkinson EA (2004) Predators select against high growth rates and risk–taking behaviour in domestic trout populations. Proc R Soc Lond B Biol Sci 271:2233–2237. doi:10.1098/rspb.2004.2861CrossRefGoogle Scholar
Burnham KP, Anderson DR, Huyvaert KP (2010) AIC model selection and multimodel inference in behavioral ecology: some background, observations, and comparisons. Behav Ecol Sociobiol 65:23–35. doi:10.1007/s00265-010-1029-6CrossRefGoogle Scholar
Chapuisat M, Goudet J, Keller L (1997) Microsatellites reveal high population viscosity and limited dispersal in the ant formica paralugubris. Evolution 51:475–482. doi:10.2307/2411120CrossRefGoogle Scholar
Dornhaus A, Holley J-A, Pook VG et al (2008) Why do not all workers work? Colony size and workload during emigrations in the ant Temnothorax albipennis. Behav Ecol Sociobiol 63:43–51. doi:10.1007/s00265-008-0634-0CrossRefGoogle Scholar
Dornhaus A, Holley J-A, Franks NR (2009) Larger colonies do not have more specialized workers in the ant Temnothorax albipennis. Behav Ecol. doi:10.1093/beheco/arp070Google Scholar
Fisher J (1954) Evolution and bird sociality. Evol Process 71–83Google Scholar
Goldberg JL, Grant JWA, Lefebvre L (2001) Effects of the temporal predictability and spatial clumping of food on the intensity of competitive aggression in the Zenaida dove. Behav Ecol 12:490–495. doi:10.1093/beheco/12.4.490CrossRefGoogle Scholar
Kelley OJ, Hunter AS, Haise HR, Hobbs CH (1946) Comparison of methods of measuring soil moisture under field conditionsGoogle Scholar
Lima SL (1998) Stress and decision-making under the risk of predation: recent developments from behavioral, reproductive, and ecological perspectives. Advances in the study of behavior: stress and behavior. Academic PressGoogle Scholar
McGlone J, Stansbury W, Tribble L (1987) Effects of heat and social stressors and within-pen weight variation on young pig performance and agonistic behavior. J Anim Sci 65:456–462PubMedGoogle Scholar
Partridge LW, Partridge KA, Franks NR (1997) Field survey of a monogynous leptothoracine ant (Hymenoptera, Formicidae) evidence of seasonal polydomy ? Insect Soc 44:75–83. doi:10.1007/s000400050031CrossRefGoogle Scholar