The ontogeny of personality traits in the desert funnel‐web spider, Agelenopsis lisa (Araneae: Agelenidae)

Abstract

Trait consistency over time is one of the cornerstones of animal personality. Behavioral syndromes are the result of correlations between behaviors. While repeatability in behavior is not a requirement for behavioral syndromes, the two concepts studied together provide a more comprehensive understanding of how behavior can change over ontogeny. The roles of ontogenetic processes in the emergence of personality and behavioral syndromes have received much individual attention. However, the characterization of both individual trait consistency and behavioral syndromes across both sexes, as in our study, has been relatively rare. Ontogeny refers to changes that occur from conception to maturation, and juveniles might be expected to undergo different selection pressures than sexually mature individuals and also will experience profound changes in hormones, morphology, and environment during this period. In this study, we test for behavioral trait consistency and behavioral syndromes across six time points during ontogenetic development in the desert funnel‐web spider (Agelenopsis lisa). Our results indicate behavioral traits generally lack consistency (repeatability) within life stages and across ontogeny. However, penultimate males and mature females do exhibit noticeable mean‐level changes, with greater aggressive responses toward prey, shorter latencies to explore their environment and in the exhibition of risk‐averse responses to predatory cues. These traits also show high repeatability. Some trait correlations do exist as well. In particular, a strong correlation between aggressiveness toward prey and exploration factors is observed in mature males. However, because correlations among these factors are unstable across ontogeny and vary in strength over time, we conclude that behavioral syndromes do not exist in this species. Nevertheless, our results indicate that increased consistency, increasing average trait values, and varying correlations between traits may coincide with developmentally important changes associated with sexual maturation, albeit at different time points in males and females. This period of the life cycle merits systematic examination across taxa.

Beyond spider personality: The relationships between behavioral, physiological, and environmental factors

“…Throughout their lifetime, animals undergo a sequence of physiological changes in response to environmental changes and experience, which affect the development and expression of behavioral and morphological traits (Bosco et al., 2017). Developmental changes in behavior and physiology that spiders experience from juvenile stages to adulthood can provide us with a better understanding of sexual selection, sexual dimorphism, and sexual conflict, and how apparently nonadaptive behaviors can be maintained in spider populations (Elgar & Schneider, 2004; Johnson & Sih, 2005; Santana et al., 2017).…”

“…For example, while aggressive spiders under low population density tend to have higher quality territories, they also suffer higher mortality (Fogarty et al., 2011; Keiser et al., 2018; Kralj‐Fišer et al., 2017; Réale et al., 2007; Riechert & Hedrick, 1993; Sih et al., 2015). As a consequence of how ontogenetic effects impact the expression of particular behaviors (Langenhof & Komdeur, 2018), it is also necessary to understand how ontogenetic factors affect individual personalities and, ultimately, population‐level behavioral syndromes (Bosco et al., 2017; Branch et al., 2015; Sih & Bell, 2008). Furthermore, it is important to consider how different behavioral types, exhibited over the course of an individual's development, are affected in response to environmental changes (Langenhof & Komdeur, 2018).…”

“…Consistent individual variation in behavior between adults (personality) and its correlation across different contexts (behavioral syndrome) is not necessarily present during all life stages in some animals (e.g., zebra finches, Taeniopygia guttata , Wuerz & Krüger, 2015), including spiders (Bosco et al., 2017; Parthasarathy et al., 2019). Early life stages are often more sensitive to environmental conditions, such as temperature, population density and food availability, which can affect the presence or absence of behavioral syndromes.…”

“…Early life stages are often more sensitive to environmental conditions, such as temperature, population density and food availability, which can affect the presence or absence of behavioral syndromes. For example, boldness in the desert funnel‐web spider, Agelenopsis lisa , tested across different contexts (foraging, placement in a new environment and response to predation) was not consistent across different ontogenetic stages, apart from the penultimate stage (Bosco et al., 2017). The aggressiveness‐boldness syndrome observed in these spiders during the penultimate stage is commonly seen in males close to maturity because they need to increase their mass, which is associated with increased mating success as adults (Bosco et al., 2017).…”

“…To understand how and why spider personality is maintained across different contexts, we need a comprehensive understanding of what intrinsic (i.e., physiological mechanisms, such as hormones, silks and venoms; van Oers & Mueller, 2010) and extrinsic (e.g., environment) factors, and their interactions (Figure 1), directly and/or indirectly affect behaviors over the lifetime of individuals (ontogeny; Jandt et al., 2014; Kralj‐Fišer & Schuett, 2014). Although some studies investigating spider personalities have considered some underlying mechanisms independently (Bosco et al., 2017; Langenhof & Komdeur, 2018; Liedtke et al., 2015), there is still a general lack of understanding of how the various intrinsic and extrinsic factors affect the evolution of personality, as well as how they might affect behavioral plasticity (Dingemanse et al., 2010; Dingemanse & Wolf, 2010). Knowing what factors affect morphophysiological traits will provide insights into fitness and general success of spider populations (Figure 1), including how populations respond to threats, overcome challenges, and manage the costs and benefits associated with personalities (in particular, behavioral types) occurring under different conditions (Keiser et al., 2018; Kralj‐Fišer & Schuett, 2014).…”