Mink with Divergent Activity Levels have Divergent Reproductive Strategies

摘要: Stable individual differences in activity levels within populations have been linked to reproductive rate or parental care several species, including American mink (Neovison vison). Fur-farmed are good models for studying such effects because they yield large sample sizes and readily allow investigations into maternal behaviour, success, offspring performance the relationships between these factors. On farms, very inactive individuals generally smaller litters, this held true our study populations. We tested two competing hypotheses explain this: (1) failing cope with a challenging environment experiencing chronic stress and/or depression-like ‘apathy’; predicts female-skewed poorer care, higher infant mortality growth (2) do not reduced fitness but instead employ an alternative adaptive strategy, trading off quantity quality; enhanced growth. Inactive females’ kits, especially their sons, grew faster than active females’, even after statistically controlling litter size; by 21 d, dams’ litters no longer differed total biomass, despite former’s sizes. In kit retrieval tests, females were dams reach sons (as well as more likely contact daughters: bias towards male kits evident dams). Furthermore, rates dam latencies touch them co-varied, suggesting existence of consistent style across dams. Hypothesis 2 was thus supported: favour quality over quantity, investing resources fewer particularly males. This potentially boosts sons’ adult fitness. More broadly laboratory-based studies, possible ‘captivity effects’ on correlates other personality traits discussed.