A new paper by PRIMARCH project member Bill McGrew (McGrew 2014) reviews what we currently know about primate insect-eating. Building on an earlier review (McGrew 2001), he finds that discussion of the evolution of human animal consumption is still heavily biased towards hunting and carnivory, despite the often high prevalence of insect consumption by modern human and non-human primates. Among non-human primates, chimpanzees have developed the most extensive array of tools to access insect prey such as ants, bees and termites, although the relationship between tool use and insectivory is not straightforward, as recent work on the Ugandan Bulindi chimpanzees (McLennan 2014) demonstrates. Other primates have also developed strategies to access both insects and arthropods, such as Brazilian capuchin monkeys using stone tools to dig for spiders (Mannu & Ottoni 2009).
McGrew discusses several lines of evidence that may enhance our knowledge of when and how insect eating developed, including residues and use-wear on processing tools, coprolites, stable isotope evidence of diet, and even depictions of insect-eating on cave walls. Interestingly, he also describes work in progress suggesting that termite-fishing frequency in female chimpanzees at Gombe may be linked to a fitness advantage, in terms of lifetime reproductive success. Few studies have been able to tie tool-use to reproductive success (see Biro et al. 2013), and the long-term datasets held by chimpanzee field sites will play an important role in testing how behaviours such as insectivory may drive both technological evolution and natural selection in primates.
McGrew’s review paper is in press in the Journal of Human Evolution, and is part of a forthcoming special issue of that journal focused on the evolution of insect consumption.
Biro, D., Haslam., M., & Rutz, C., 2013. Tool use as adaptation. Philosophical Transactions of the Royal Society B 368:20120408.
Mannu, M., & Ottoni, E., 2009. The enhanced tool-kit of two groups of wild bearded capuchin monkeys in the Caatinga: tool making, associative use, and secondary tools. American Journal of Primatology 71:242-251.
McGrew, W.C., 2001. The other faunivory: primate insectivory and early human diet. In: Stanford, C.B., Bunn, H.T. (Eds.), Meat-eating and Human Evolution. Oxford University Press, Oxford, pp. 160-178.
McGrew, W.C., 2014. The ‘other faunivory’ revisited: Insectivory in human and non-human primates and the evolution of human diet. Journal of Human Evolution doi:10.1016/j.jhevol.2013.07.016
McLennan, M., 2014. Chimpanzee insectivory in the northern half of Uganda’s Rift Valley: do Bulindi chimpanzees conform to a regional pattern? Primates doi:10.1007/s10329-014-0408-4