Lifespan and age, but not residual reproductive value or condition, are related to behaviour in wild field crickets

Abstract

Individuals frequently show long‐term consistency in behaviour over their lifetimes, referred to as “personality.” Various models, revolving around the use of resources and how they are valued by individuals, attempt to explain the maintenance of these different behavioural types within a population, and evaluating them is the key for understanding the evolution of behavioural variation. The pace‐of‐life syndrome hypothesis suggests that differences in personalities result from divergent life‐history strategies, with more active/risk‐taking individuals reproducing rapidly but dying young. However, studies of wild animals provide only limited support for key elements of this and related hypotheses, such as a negative relationship between residual reproductive value and activity. Furthermore, alternative models make divergent predictions regarding the relationship between risk‐taking behaviours and variables consistent in the short‐term, such as condition. To test these predictions, we regularly measured willingness to leave a shelter and the activity level of wild adult field crickets (Gryllus campestris) at both short and long intervals over their entire adult lives. We found some support for a pace‐of‐life syndrome influencing personality, as lifespan was negatively related to willingness to leave the shelter and activity. Crickets did not appear to protect their “assets” however, as estimates of residual reproductive value were not related to behaviour. Although there was considerable variance attributed to the short‐term consistency, neither trait was affected by phenotypic condition, failing to support either of the models we tested. Our study confirms that behaviours may covary with some life‐history traits and highlights the scales of temporal consistency that are more difficult to explain.

Comparing individual and population measures of senescence across 10 years in a wild insect population

“…; Fisher et al. ). Adult G. campestris are closely associated with burrows, which facilitates the recording of survival and behavioral data over individuals’ entire adult lives.…”

“…Over 10 years (10 generations), we have been monitoring the survival and behavior of a natural population of the field cricket Gryllus campestris, living in a meadow in north Spain (Rodríguez-Muñoz et al 2010;Rodríguez-Muñoz et al 2011;Fisher et al 2016;Fisher et al 2018). Adult G. campestris are closely associated with burrows, which facilitates the recording of survival and behavioral data over individuals' entire adult lives.…”

Individual plasticity drives boldness senescence in a territorial butterfly

“…Individual plasticity of personality traits as individuals get older has been reported a few times, but the direction of those changes appears to vary among species. For example, handling aggression decreased with age in a wild population of Great tits ( Parus major ) (Class & Brommer, 2016), while activity and the tendency to leave a tube both increased as individual Field crickets ( Gryllus campestris ) get older (Fisher et al., 2018; Fisher, David, Tregenza, & Rodríguez‐Muñoz, 2015). The direction of the change probably depends on the trait itself, how it relates to fitness components and the proximate mechanism underlying this change.…”

“…Recent studies have shown that personality changes with age (e.g., Favati, Zidar, & Thorpe, 2016; Humphries, McAdam, Boutin, & Kelley, 2015; Polverino, Cigliano, Nakayama, & Mehner, 2016; Stanley, Mettke‐Hofmann, & Preziosi, 2017). Although only few studies have tried to tease apart within‐ and between‐individual changes, age‐related changes in personality traits appear so far to be mainly caused by within‐individual changes (i.e., individual plasticity) (e.g., Class & Brommer, 2016; Fisher, David, Rodríguez‐Muñoz, & Tregenza, 2018).…”

Interspecific interference competition between two field cricket species

“…Mating behavior of field crickets can be observed in natural or seminatural conditions (e.g. Zuk 1988;Simmons & Zuk 1992;Simmons 1995;Fisher et al 2018). Therefore, field cricket species are one of the most suitable model systems to investigate species interactions.…”