Preimaginal and Adult Experience Modulates the Thermal Response Behavior of Ants

Abstract

Colonies of social insects display an amazing degree of flexibility in dealing with long-term and short-term perturbations in their environment. The key organizational element of insect societies is division of labor. Recent literature suggests that interindividual variability in response thresholds plays an important role in the emergence of division of labor among workers (reviewed in [1, 2]). Genetic variation can only partly explain the variability among workers. Here we document the effects of both preimaginal and adult thermal experience on the behavioral differentiation of Camponotus rufipes ant workers. We show that preimaginal temperature (22 degrees C or 32 degrees C during pupal stage) affects temperature-response thresholds and temperature preferences of adult brood-tending workers. We further show that brood-carrying experience gathered as adult during several repeated temperature increases modifies thermal behavior. Experienced workers showed a faster transition from first sensing the temperature stimulus to responding with brood translocation. Developmental plasticity of workers provides a colony with flexibility in dealing with thermal variations and constitutes an important mechanism underlying interindividual variability. Adult thermal experience further fine tunes the behavioral response thresholds and reinforces behavioral differentiation among workers.

Ventilation response thresholds do not change with age or self-reinforcement in workers of the bumble bee Bombus impatiens

“…Not only are rearing conditions important for proper brood development, but they also affect adult behavior (Heinrich, 1979;Jones and Oldroyd, 2007 for review;Weidenmüller et al, 2009). Bumblebees build their nests within underground cavities (most species), and colonies may experience fluctuations in ambient temperatures.…”

“…The factors that may influence inter-individual variation in response thresholds include genotypic variation (Beshers and Fewell, 2001;Jones et al, 2004;Oldroyd and Fewell, 2007;Duong and Schneider, 2008), age (Robinson, 1987;Pankiw and Page, 1999), rearing conditions (Weidenmüller et al, 2009), and learning in the form of self-reinforcement (Theraulaz et al, 1998;Weidenmüller, 2004;Ravary et al, 2007). In the context of response thresholds, self-reinforcement has been proposed to result in: (1) a decrease in response threshold when the associated task is performed, leading to specialization, or (2) an increase in response threshold when the task is not performed, decreasing the probability of performing that task (Theraulaz et al, 1998).…”

When doing nothing is something. How task allocation strategies compromise between flexibility, efficiency, and inactive agents

“…Finally, individuals may choose their tasks based on their own experiences-for example depending on the frequency with which a worker has either performed (Weidenmüller et al 2009), or successfully accomplished (Ravary et al 2007) a task in the past. It is important to state here that we are describing a mechanism of choosing tasks, which may or may not relate to how well workers can actually perform a task (Dornhaus 2008); 'learning' here thus refers to changes, in response to experience, in a workers' probability of deciding to perform certain tasks.…”

Environmental temperature affects the dynamics of ingestion in the nectivorous ant Camponotus mus

“…For example, during the embryonic phase, temperature affects time of development (flies, mosquitoes, butterflies, beetles: Ratte, 1985), larval growth (blowflies: Hückesfeld et al, 2011), brain synaptic organization (honeybees: Groh et al, 2004). During adult life, it affects behavioral responses (ants: Weidenmüller et al, 2009), longevity, size and weight, fecundity (Ratte, 1985), gustatory responses (blowflies: Dethier and Arab, 1958; fruit flies: Napolitano et al, 1986), locomotion (dragonflies: May, 1981;beetles: Oertli, 1989; ants: Heinrich, 1993) and foraging preferences (bumblebees: Whitney et al, 2008), among others.…”