Does is pay to be smart? Cognition and fitness in gray mouse lemurs (Microcebus murinus)
Final Report Abstract
Different species vary widely in brain size and the associated cognitive abilities, but the selective factors shaping this variation remain hotly debated. Because differences in these traits must evolve within species, we tested the fundamental assumption that inter-individual variation in cognitive abilities must co-vary positively with fitness proxies in this project. To date, other studies on this topic had typically examined the correlation between 1 or 2 cognitive test performances with a measure of reproductive success (e.g. number of eggs), and virtually all of these studies were conducted with birds. Because these studies yielded variable results and did not include any primates or other large-brained mammals, we launched an experimental study on this topic with wild primates. To this end, we brought a total of 164 mouse lemurs from our long-term study site in western Madagascar into temporary captivity for 1-3 night, where they were subjected to 10 different tests that tap into distinctive cognitive abilities for which we derived a priori links to their ecological relevance. Because test performance may also be impacted by other intrinsic traits, we subjected all individuals also to two standard personality tests. In total, we performed more than 2.000 of these experimental tests and released all test animals at the site of capture, where they struggled to survive and reproduce under natural conditions. The key result obtained so far revealed that survival after testing was indeed predicted by performance in cognitive tests but also by sex and body mass at testing, whereas neophobia and activity did not predict survival. Potential links to variation in measures of reproductive success will be examined in the near future. This project also offered an opportunity to compare two sympatric species that differ in aspects of ecological specialization, yielding several unplanned publications. The study was featured in a popular German TV program (“Terra X” by ARTE and ZDF), which was watched by an audience of > 5 million upon the first broadcast.
Publications
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(2018) Are generalists more innovative than specialists? A comparison of innovative abilities in two wild sympatric mouse lemur species. Royal Society Open Science 5: 180480
Henke-von der Malsburg J, Fichtel C
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(2018). Linking cognition with fitness in a wild primate: Fitness correlates of problem-solving performance and spatial learning ability. Philosophical Transactions of the Royal Society B 373:20170295
Huebner F, Fichtel C, Kappeler PM
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(2018). The repeatability of cognitive performance: a meta-analysis. Philosophical Transactions of the Royal Society B: Biological Sciences 373:20170281
Cauchoix M, Chow PKY, van Horik JO, Atance CM, Barbeau EJ, Barragan-Jason G, Bize P, Boussard A, Buechel SD, Cabirol A, Cauchard L, Claidière N, Dalesman S, Devaud JM, Didic M, Doligez B, Fagot J, Fichtel C, Henke-von der Malsburg J, Hermer E, Huber L, Huebner F, Kappeler PM, Klein S, Langbein J, Langley EJG, Lea SEG, Lihoreau M, Lovlie H, Matzel LD, Nakagawa S, Nawroth C, Oesterwind S, Sauce B, Smith EA, Sorato E, Tebbich S, Wallis LJ, Whiteside MA, Wilkinson A, Chaine AS, Morand-Ferron J
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(2020). Cognition in the wild: Individual differences in cognitive abilities and their link with fitness in a wild primate, the grey mouse lemur (Microcebus murinus). PhD thesis, University of Göttingen
Huebner F
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(2020). Linking ecology and cognition: does ecological specialisation predict cognitive test performance? Behavioral Ecology and Sociobiololgy 74:154
Henke-von der Malsburg J, Kappeler PM, Fichtel C
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(2021). Cognitive adaptations in two sympatric mouse lemur species occupying different ecological niches. PhD thesis, University of Göttingen
Henke-von der Malsburg J
