Evolution of insect learning styles and behavioural syndromes in response to environmental variability and reliability of information.
Evolution, Anthropology
Final Report Abstract
In this research project, I have set out to explore how predictability of information can drive the evolution of learning ability. Although the initially planned experimental set-up was unsuccessful, we did manage to demonstrate the existence of natural variation in learning ability in a wild population of Nasonia vitripennis parasitoid wasps. By exploring the search efficiency of strains with high versus low learning ability in different search scenarios in which information was more of less reliable, we were further able to research the ecological costs and benefits of learning ability. An important find is that when information reliably indicated host presence, this knowledge leads to shorter search times while it leads to costly misdirected behaviour if it is unreliable. The outcome of this trade-off is different for the different learning phenotypes that we have found to be present in a natural population of Nasonia vitripennis. Strains with high learning ability (i.e., swift formation of memory after a single positive associative experience) benefit more from the information learned during a prior experience than strains with low learning scores. Yet these high learning strains also pay a higher price if the readily learned information turns out to be unreliable. Strains for which a single prior experience does not readily lead to a stable association do not profit from the information when it is indicative of host presence, but they also do not suffer costs due to misdirected behaviour either. These results clearly demonstrate that the relationship between learning ability and fitness need not be linear, and insights form this research form an important step into explaining why directional selection towards more enhanced learning is not frequently observed in natural populations. Likely, as has been suggested before (Boogert et al., 2018), a form of stabilizing selection is more common and this should be addressed in future studies. More effort should be directed into studying variation in learning behaviour in the wild. This study is a step in the right direction; although still not set in a completely natural setting, we did consider strains from a natural population in a laboratory setting and present the wasps with an ecologically relevant scenario. I certainly hope these results will bridge the gap towards further testing these theories under natural conditions, because we still need to better understand the actual significance of learning in nature.
Publications
- (2018). Regulatory and sequence evolution in response to selection for improved associative learning ability in Nasonia vitripennis. BMC Genomics, 19, 892
Kraaijeveld, K., Oostra, V., Liefting, M., Wertheim, B., Meijer, E. de, & Ellers, J.
(See online at https://doi.org/10.1186/s12864-018-5310-9) - (2018). Selection for associative learning of color stimuli reveals correlated evolution of this learning ability across multiple stimuli and rewards. Evolution, 72(7)
Liefting, M., Hoedjes, K. M., Le Lann, C., Smid, H. M., & Ellers, J.
(See online at https://doi.org/10.1111/evo.13498) - (2019). What are the costs of learning? Modest trade-offs and constitutive costs do not set the price of fast associative learning ability in a parasitoid wasp. Animal Cognition, 22(5), 851–861
Liefting, M., Rohmann, J. L., Le Lann, C., & Ellers, J.
(See online at https://doi.org/10.1007/s10071-019-01281-2) - (2020). Strain differences rather than species differences contribute to variation in associative learning ability in Nasonia. Animal Behaviour, 168, 25–31
Liefting, M., Verwoerd, L., Dekker, M. L., Hoedjes, K. M., & Ellers, J.
(See online at https://doi.org/10.1016/j.anbehav.2020.07.026)
