Integrating social networks, animal personalities, movement ecology and parasites: a framework with examples from a lizard

We describe a conceptual framework integrating animal personalities, movement ecology, social networks and parasite transmission. For directly transmitted parasites, parasite transmission depends on social interaction patterns that can be quantified using social network metrics. For indirectly transmitted parasites, the key can be transmission networks that quantify time-lagged contacts (e.g. where potential hosts visit locations used earlier by infected hosts). Social network connections (time-lagged or not) often result from shared space use determined by individual movements in response to key environmental factors. Movement ecology provides a framework for understanding these responses. Finally, individuals with different personalities likely respond differently to environmental factors in ways that influence the movements and space use that underlie network connectivity, which, in turn, affects parasite loads and transmission. We illustrate these key points with recent work on sleepy lizards, Tiliqua rugosa, and their ticks. By GPS tracking of nearly all adult lizards at our site, we found that lizards that more frequently shared the same refuges (where ticks detach and reattach to a new host) used earlier by other lizards tended to indeed have higher tick loads. Higher shared refuge use was associated with greater shared space use, in general. Shared space use with conspecifics was reduced by the lizards' general propensity (quantified by analyses of 279 985 GPS locations for 72 lizards) to avoid conspecifics, but enhanced by their general tendency to prefer areas with more resources and better refuge (in particular, late in the season when food was scarce and conditions were hotter and drier). Both of these tendencies were personality dependent. Less aggressive lizards exhibited both a stronger attraction to areas with more food and better refuge, and a stronger tendency to avoid other lizards. We conclude by discussing implications of our results for the general conceptual framework and suggest future directions.