Individual variation in ballooning dispersal by black widow spiderlings: The effects of family and social rearing

Abstract

Individual behavioral variation is ubiquitous across taxa and important to understand if we wish to fully use behavioral data to understand the ecology and evolution of organisms. Only recently have studies of individual variation in dispersal behavior become a focus of research. A better understanding of individual variation in dispersal behavior is likely to improve our understanding of population dynamics. In particular, the dynamics of critically small populations (endangered species) and large populations (pest species) may be driven by unique dispersal variants. Here we documented individual variation in the ballooning dispersal behavior of Western black widow spiderlings Latrodectus hesperus, an urban pest species found in superabundant infestations throughout cities of the desert Southwest USA. We found a great deal of family-level variation in ballooning dispersal, and this variation was highly consistent (repeatable) across time. Maternal egg investment was a poor predictor of this ballooning dispersal. Instead, we show that spiderlings reared in isolation are significantly slower to disperse than spiderlings raised in a more natural setting surrounded by full siblings. Thus, our study examines a widespread but poorly understood dispersal behavior (ballooning), and suggests urban pest population dynamics are likely driven by the interaction of variation in individuals, families and social environments.

The importance of growing up: juvenile environment influences dispersal of individuals and their neighbours

“…Early environment also influences dispersal behaviour, such as of the western black widow spider ( Latrodectus hesperus Chamberlin & Ivie), which disperses less via ballooning behaviour when reared in isolation in the laboratory than when reared in cohorts under more natural conditions (Johnson et al . ). Studies such as these have been tremendously informative in revealing factors that alter patterns of dispersal within natural habitats.…”

“…For example, developing at high density increases dispersal capacity of the planthoppers Prokelisia marginata (van Duzee) and Prokelisia dolus (Wilson) by triggering production of fully-winged migratory morphs (Denno & Roderick 1992). Early environment also influences dispersal behaviour, such as of the western black widow spider (Latrodectus hesperus Chamberlin & Ivie), which disperses less via ballooning behaviour when reared in isolation in the laboratory than when reared in cohorts under more natural conditions (Johnson et al 2015). Studies such as these have been tremendously informative in revealing factors that alter patterns of dispersal within natural habitats.…”

Sibship effects on dispersal behaviour in a pre‐industrial human population

“…Moreover, sibling interactions can lead to intrafamilial differences in dispersal patterns that have been related to parental favouritism (Ekman et al, 2001;Ragheb & Walters, 2011), competitive asymmetries between siblings (Strickland, 1991;Ekman et al, 1999;Ellsworth & Belthoff, 1999), different family sizes (Kisdi, 2004) or the existence of territorial bequeath (Jacquot & Vessey, 1995;Ragsdale, 1999). Although these variables are likely to strongly interact with each other in modifying dispersal patterns, their influence have rarely been investigated together (for exceptions see Pasinelli & Walters, 2002;Scandolara et al, 2014b;Johnson et al, 2015). However, such multivariate analysis is essential for a comprehensive understanding of dispersal and its determinants in family-living species.…”

Early Environmental Conditions Shape Personality Types in a Jumping Spider

“…More studies are now desirable that investigate whether behavioral differences induced by developmental effects are consistent and stable, i.e., whether environmental conditions experienced influence animal personalities. Indeed, there is an increasing number of studies focusing on the development of animal personality (e.g., Sinn et al, 2008;Brodin, 2009;Schuett et al, 2011a;Gyuris et al, 2012;Hedrick and Kortet, 2012;Niemelä et al, 2012b;Petelle et al, 2013;Sweeney et al, 2013;Tremmel and Müller, 2013;Guenther et al, 2014;Johnson et al, 2015). To clearly identify underlying processes, experimental studies in which environmental conditions are manipulated are needed.…”