Behavioural tendencies associated with microhabitat use in a clonal gecko species living in the wild

Boldness affects novel object recognition in a gecko species

Individual animals exhibit considerable differences in cognitive characteristics associated with personality differences. The cognition-personality link was intensively investigated in the last decade though with mixed results. To grasp the general pattern, a common method should be applied to a wide range of animals. We tested novel object recognition (NOR) in the mourning gecko (Lepidodactylus lugubris) and investigated whether boldness, assessed in an anti-predator context, explained neophobia and how much attention animals pay to their surroundings. Boldness did not simply explain object neophobia but predicted attention to novel objects. Specifically, shy geckos showed shorter latency to approach the novel object than bold geckos only in the changed situation in which distinct types of objects were presented in two successive phases. However, no significant effect of boldness was detected in the unchanged situation in which the same object was presented twice. Our findings suggest that, in the mourning gecko, (1) boldness and object neophobia represent different aspects of personality traits and that (2) boldness underlies sensitivity to slight changes in the environment.

The effects of animal personality on the ideal free distribution

The ideal free distribution (IFD) has been used to predict the distribution of foraging animals in a wide variety of systems. However, its predictions do not always match observed distributions of foraging animals. Instead, we often observe that there are more consumers than predicted in low-quality patches and fewer consumers than predicted in high-quality patches (i.e. undermatching). We examine the possibility that animal personality is one explanation for this undermatching. We first conducted a literature search to determine how commonly studies document the personality distribution of populations. Second, we created a simple individual-based model to conceptually demonstrate why knowing the distribution of personalities is important for studies of populations of foragers in context of the IFD. Third, we present a specific example where we calculate the added time to reach the IFD for a population of mud crabs that has a considerable number of individuals with relatively inactive personalities. We suggest that animal personality, particularly the prevalence of inactive personality types, may inhibit the ability of a population to track changes in habitat quality, therefore leading to undermatching of the IFD. This may weaken the IFD as a predictive model moving forward.

Epigenetic anticipation for food and reproduction

Physiological changes in anticipation of cyclic environmental events are common for the persistence of populations in fluctuating environments (e.g. seasons). However, dealing with sporadic resources such as the intermittent production of seed masting trees may be challenging unless reliable cues also make them predictable. To be adaptive, the anticipation of such episodic events would have to trigger the corresponding physiological response. Epigenetic modifications could result in such physiological anticipatory responses to future changes. The eastern chipmunk (Tamias striatus) is known to adjust its reproductive activity to match juvenile weaning with peak seed availability of masting trees, which are essential for their survival. We therefore expected that epigenetic changes would be linked to spring reproductive initiation in anticipation for beech seed availability in fall. We correlated the variation of DNA methylation profiles of 114 adult chipmunks captured in May with beech seeds abundance in September, over 4 years, for three distinct populations, as well as individuals sampled twice during reproductive and non-reproductive years. The significant correlation between spring epigenetic variation and the amount of food in the fall confirmed the phenotypic flexibility of individuals according to environmental fluctuations. Altogether, these results underlined the key role of epigenetic processes in anticipatory responses enabling organisms to persist in fluctuating environments.