Abstract
Consistent among-individual differences in behavior have been described in numerous taxa. More recently, the hypothesis that such behavioral variation may also correlate to life-history traits, such as investment in current or future reproduction, has been proposed as a potential explanation for why variation is maintained among and within populations. A continual challenge in measuring the integration of these traits, or the pace-of-life syndrome (POLS), is to find a reliable and quantifiable proxy for energy allocation between reproduction and self-maintenance. Here, I address this challenge using the eusocial insects, Temnothorax ants, in a common garden experiment to directly quantify energy allocation by tracking the number of sterile workers (somatic effort) and winged reproductive ants (reproductive effort) produced across years. I use colonies collected from populations previously demonstrated to show significant differences in a risk-tolerance behavioral syndrome. I provide an empirical test of the POLS hypothesis between 2 populations of Temnothorax ants over three years. I find strong evidence for a POLS between populations and weaker, but present support for a within population POLS. More risk-tolerant populations also allocate more energy towards reproduction and grow faster across years. This study then emphasizes the value of a more holistic study of among-individual variation. Additionally, it suggests more research is needed on understanding how and why traits may correlate in some populations, but remain independent in others.
