An experimental approach to the formation of diet preferences and individual specialisation in European mink

Abstract

Individual dietary specialisation can occur within populations even when average diets suggest that the population has a generalist feeding strategy. Individual specialisation may impact fitness and has been related to demographic traits, ecological opportunity, competition, learning and animal personality. However, the causation and formation of individual specialisation are not fully understood. Experiments on animals raised in controlled environments provide an opportunity to examine dietary preferences and learning largely independent from variation in lifetime experiences and ecological opportunity. Here, we use a feeding experiment to examine individual specialisation and learning in captive bred European mink (Mustela lutreola) in an Estonian conservation programme. In a series of cafeteria experiments, animals could choose between one familiar food item (Baltic herring Clupea harengus membras) and two initially novel ones (noble crayfish Astacus astacus and house mouse Mus musculus). In general, mice were rarely eaten whilst crayfish consumption increased over time and fish decreased. At the individual level, there was a mix of generalists and crayfish or fish specialists, and the individuals differed in learning time in relation to novel prey. Our results indicate that individual variation in innate preferences and learning both contributes to individual diet specialisation. The differences in learning indicate individual variation in behavioural plasticity, which in turn can be related to personality. This could be of concern in conservation, as personality has been shown to affect survival in translocations.

A systematic review of animal personality in conservation science

“…We also advise looking for opportunities to record behaviors repeatedly across time and contexts without altering what would already be occurring because this is one of the easiest and most cost‐effective ways for conservationists to incorporate personality into their programs. Many of the reports in our review tested animals as part of ongoing conservation programs, such as an ongoing reintroduction program for European mink (Haage, Angerbjörn, et al., 2017 ), conditioned taste aversion training with yellow‐spotted monitors (Ward‐Fear et al., 2020 , 2019 ), and regular breeding‐season monitoring of Montagu's harrier ( Circus pygargus ) nesting (Mougeot & Arroyo, 2017 ). Due to the longitudinal nature of these projects, multiple measures of individuals were able to be made over time and the repeatability of behaviors could be examined easily.…”

How was genetic diversity transferred with translocations from ex situ to in situ? A case study of the European mink translocation to Hiiumaa Island in Estonia

“…Interestingly, there is no “mother's curse” in the European mink captive population (Gemmell et al, 2004) ‐ the effect of mtDNA on fitness and population viability—that may affect the occurrence of haplotypes in the captive population of European mink (personal communication, Philippe Helsen and Marloes Leeflang). That means that the likelihood of a few surviving mink contributing to the start of a wild population is rather low and is dependent upon chance and potentially also on behavioral variation within translocated animals (Haage et al, 2017; Harrington et al, 2014). Keeping this in mind, regular long‐term translocation can be regarded as an important strategy in designing release operations.…”