Personality composition alters the transmission of cuticular bacteria in social groups

Abstract

The initial stages of a disease outbreak can determine the magnitude of the ensuing epidemic. Though rarely tested in unison, two factors with important consequences for the transmission dynamics of infectious agents are the collective traits of the susceptible population and the individual traits of the index case (i.e. 'patient zero'). Here, we test whether the personality composition of a social group can explain horizontal transmission dynamics of cuticular bacteria using the social spider Stegodyphus dumicola. We exposed focal spiders of known behavioural phenotypes with a GFP-transformed cuticular bacterium (Pantoea sp.) and placed them in groups of 10 susceptible individuals (i.e. those with no experience with this bacterium). We measured bacterial transmission to groups composed of either all shy spiders, 10% bold spiders or 40% bold spiders. We found that colonies with 40% bold spiders experienced over twice the incidence of transmission compared to colonies with just 10% bold individuals after only 24 h of interaction. Colonies of all shy spiders experienced an intermediate degree of transmission. Interestingly, we did not detect an effect of the traits of the index case on transmission. These data suggest that the phenotypic composition of the susceptible population can have a greater influence on the degree of early transmission events than the traits of the index case.

Covariation between the physiological and behavioral components of pathogen transmission: host heterogeneity determines epidemic outcomes

“…Much of this predictive power is likely a function of how the model structured, where roughly onethird of the population is not susceptible (s  0) or not infectious (κ  0). While such extreme physiological phenotypes might be less common in natural populations, this theoretical finding does support the results of recent empirical work where the index case and group composition of phenotype played important roles in epidemic outcomes (Adelman et al 2015, Keiser et al 2016. Across the three different mechanisms, negative covariation decreased maximum prevalence, increased time to reach maximum prevalence, and dampened the rate at which the disease spread through the population relative to all other types of covariation.…”

“…In particular, improvements in radiotelemetry, radio-frequency identification (RFID), and temperature sensing passive integrated transponder (PIT) tags may allow for concrete steps forward in the simultaneous collection of contact and sick- ness behavior (Adelman et al 2014). The type of dynamic network modelling presented here could be used to explicitly investigate ratios and index cases of behavioral and physiological phenotypes in closed populations (Keiser et al 2016). Host heterogeneity in contact rate and physiology and potential covariations between these two components exist in a myriad of real life systems (Hawley et al 2011, VanderWaal and.…”

“…the index case) and the relative composition of behavioral phenotypes (e.g. bold versus shy continuum) can substantially alter how effectively a pathogen spreads within a population (Adelman et al 2015, Keiser et al 2016.…”

Personality interacts with habitat quality to govern individual mortality and dispersal patterns

“…Seasonal changes in predator density may therefore help explain fluctuations in the distribution of personalities that have previously been observed among individual reefs (Belgrad et al., ). Such considerations toward personality distributions are important because the personality composition of populations has been found to control population mating success (Sih & Watters, ), offspring dispersal (Cote et al., ), and disease transmission (Keiser, Howell, Pinter‐Wollman & Pruitt, ).…”

Exposure to predators reduces collective foraging aggressiveness and eliminates its relationship with colony personality composition

“…These spiders are a tractable system for evaluating the magnitude of non-consumptive effects on group behavior because spider groups rely on the ability of their constituents to organize hunting groups to subdue large and occasionally dangerous prey (Keiser and Pruitt 2014; Wright et al 2015). This species also exhibits a high degree of intracolony behavioral (or personality) variation that is predictive of colony performance in foraging (Grinsted et al 2013), defensive behavior (Wright et al 2016a), web repair (Keiser et al 2016c), bacterial transmission rates (Keiser et al 2016a, b), and task differentiation among colony constituents (Wright et al 2015). In fact, colony behavioral composition is more important than colony size for predicting foraging aggressiveness and efficiency in this species (Keiser and Pruitt 2014).…”