Body mass and sex, but not breeding condition and season, influence open‐field exploration in the yellow‐necked mouse

Abstract

Theory predicts that risk taking should be influenced by external (e.g., season) and internal (e.g., breeding condition, sex, and body mass) conditions. We investigated whether these factors are associated with a potentially risky behavior: exploration of a novel environment. We conducted repeated open‐field tests of exploration in a common forest rodent, the yellow‐necked mouse Apodemus flavicollis. Contrary to expectations, the exploration did not vary with the season (spring vs. fall) or the reproductive status of the tested animals. Also unexpectedly, there was an inverted U‐shaped relationship between body mass and exploration: animals with intermediate body mass tended to have the highest exploration tendencies. Males were more exploratory than females. Finally, even after adjusting for the effects of body mass and sex, individuals exhibited consistent, repeatable differences in exploration tendencies (“behavioral types” or “personalities”). The discrepancies between certain broad generalizations and our results suggest that risk taking depends on details of species‐specific biology.

Is personality and its association with energetics sex‐specific in yellow‐necked mice Apodemus flavicollis?

“…As the Darwinian “greater male variability” hypothesis suggests, sexual selection in males is an important evolutionary process that can lead to the tendency toward heterogametic males being more variable than homogametic females, at least in some traits (Zajitschek et al, 2020 ; see for a current review, in the context of animal personality: Harrison et al, 2021 , and important commentary: Del Giudice & Gangestad, 2023 ). In our study, female and male mice did not show a great difference in any behavior, at least not at the average individual level (but see also Bednarz & Zwolak, 2022 ). Nevertheless, we found that some behavioral traits were consistent (repeatable) only in one of the sexes, despite using a comparable sample size for both.…”

“…Here we aim to test the presence of a sex‐specific relationship between physiology and personality in a single population of yellow‐necked mice Apodemus flavicollis (Figure 1 ), a common small mammal species in temperate forests. In this species, males are more proactive than females (see Bednarz & Zwolak, 2022 ), thus consistent with the POLS hypothesis, we should also expect sex‐specific differences in metabolism. Yellow‐necked mice represent an example of a polygynous species (Bryja et al, 2008 ), and thus, sexes should also differ in life histories (Tarka et al, 2018 ).…”

“…In females, both the number of crossing the center of the arena and the distance that females crossed in the arena were negatively correlated with body size and SMI (Figure 2a–c ). It is unclear whether these relationships are age (as suggested in Bednarz & Zwolak, 2022 ) or body condition dependent (Moran et al, 2021 ), however, due to a lack of repeatability, they likely have state‐dependent character rather than reflect among‐individual variation (i.e., Godfrey & Bryant, 2000 ). Contrarywise, consistent among‐individual variation in times crossing center by males (but not distance moved) was positively correlated with body size (Figure 2c ).…”

Escape tendency and the mobility behavior of four alpine rodents do not change with altitude

“…In fact, these adaptations would allow them to respond more quickly to variable and changing environments [33] . Finally, we predicted a sex-dependent effect on boldness, as previously found for A. flavicollis [34] , where males are more exploratory than females given their greater reproductive potential (H 3 ).…”

Behaviour, body mass and sex: How intraspecific variation influences seed dispersal by a scatter‐hoarding rodent

“…We tested each captured individual for behavioural type using two tests: an open‐field test to measure activity and exploration in a new environment (Bednarz & Zwolak, 2022; Montiglio et al., 2012) and a handling bag test to assess docility and struggle rate (Taylor et al., 2014). Each time we started with the handling bag test.…”