Parent personality is linked to juvenile mortality and stress behavior in the arctic fox (Vulpes lagopus)

Abstract

Life history theory predicts that individuals will differ in their risk-taking behavior according to their expected future fitness. Understanding consequences of such individual variation within a behavioral trait is crucial in explaining potential trade-offs between different traits and in predicting future dynamics in changing environments. Here, we studied individuals in a wild arctic fox population to explore if (1) individual variation in risk-taking behaviors of adult arctic foxes and in stress-dealing behaviors of their juveniles exist and are consistent over time to verify the existence of personality traits; (2) those behavioral traits in adults and juveniles are correlated; (3) they can explain fitness-related components (i.e., juvenile physical condition, mortality rate). We presented simple field experiments assessing behavioral traits by observing adult reactions toward approaching observers, and juvenile behaviors while trapping. Through the experiments, we found highly consistent individual variation of adults in vigilance and boldness levels, and more flexible juvenile behavioral traits categorized as investigating, passive, and escaping. The offspring of bolder adults exhibited more investigating behaviors and were less passive than the offspring of shy adults. Juvenile physical condition was not related to their mortality nor any behavioral traits of either parents or themselves. Lastly, highly investigating and active juveniles with bold parents had significantly lower mortality rates. This shows that interactions between parent personality and juvenile behavioral traits affect a fitness-related component in the life history of individuals. Significance statement The recent surge of interest in consistent individual difference in behavior, also called as animal personality, has already focused on its fitness consequences, but few studies have investigated the interactions between parent and offspring personality, and their ecological consequences. Moreover, this has rarely been studied in wild canids. The arctic fox is a charismatic species showing wide individual variation in behaviors. They live in highly fluctuating tundra ecosystems providing different selection regimes, making it even more eco-evolutionarily intriguing. Yet, few studies looked into behavioral traits and their importance in this system. While introducing simple methods to improve personality research in the wild, we provide a unique example of how variation in both parents and their juveniles collectively works for group dynamics in a cyclic population. This provides a firm basic for understanding behavior-mediated dynamics and opens up broader questions on how fluctuating environments exert varying pressures on individual differences.

Arctic Fox Responses to Tourism Activity

“…According to a previous study with the same arctic fox population, juveniles of bolder parents had a higher weekly survival during the summer. The boldness trait was largely determined by shorter latency to rise from lying down and shorter latency to hide when approached by a human observer (Choi et al 2019). The decreased vigilance and hiding latency found at disturbed dens in this study thus suggests a relationship between tourism activity and increased boldness.…”

“…It is difficult to distinguish whether the increased boldness is a habituation response to the disturbance or due to bolder arctic foxes inhabiting the more disturbed dens. Choi et al (2019) reported increasingly passive responses over trials in juveniles, who were tested repeatedly. In addition, we did not observe any foxes abandoning den sites close to human activity.…”

Resources and predation: drivers of sociality in a cyclic mesopredator

“…For the larger species, this switch includes arctic foxes as prey (Frafjord et al 1989 ; Tannerfeldt et al 2002 ; Larm et al 2019 ). In the Scandinavian mountain, tundra arctic foxes lost entire litters to predation by golden eagles during a crash of small rodent populations (Choi et al 2019 ). Thus, the increased intra-guild predation pressure on arctic foxes during the rodent crash years would increase the benefit of group-living despite growing scarcity of food resources.…”

“…Birds of prey and carnivores that are strongly dependent on the small rodent cycle in northern regions (Nyström et al 2006 ; Fuglei and Ims 2008 ; Hellström et al 2014 ) switch to alternative prey during a rodent population crash. The arctic fox is one such alternative prey for the red fox (Frafjord et al 1989 ; Tannerfeldt et al 2002 ), golden eagle (Choi et al 2019 ), and wolverine (Angerbjörn et al 2004 ) where especially arctic fox cubs are targeted. Thus, the intra-guild predation pressure on the arctic fox is considered to follow the small rodent (basal prey) abundance (Nyström et al 2006 ; Hellström et al 2014 ; Larm et al 2019 ), and we therefore used the small rodent phase as proxy for intra-guild predation pressure.…”

Fecal glucocorticoid metabolites as an indicator of adrenocortical activity in Arctic foxes (Vulpes lagopus) and recommendations for future studies

“…Furthermore, since the farmed foxes have close contact with humans on a daily basis, it is possible that the difference in confidence towards humans is lower compared to wild foxes. In wild Arctic foxes, bolder individuals have been found to tolerate closer approaches by a human observer before rising from lying down and fleeing or hiding, compared to shyer individuals (Choi et al 2019). Higher tolerance to humans has also been seen in foxes inhabiting den sites close to trails and tourist mountain huts (Larm et al 2020b), likely due to habituation.…”