The effects of genotype, caste, and age on foraging performance in leaf-cutting ants

Abstract

The evolution of polyandry is a general problem in behavioral ecology that has attracted particular interest in the social insects. Most social insects are monandrous (i.e., females are inseminated by a single male), but approximately a third of species have evolved polyandry (i.e., females are inseminated by multiple males), which can reach extreme levels. One of the leading explanations for polyandry is that genetically diverse colonies may have improved division of labor because of genotypic variation in the propensity of workers to engage in particular tasks. Here we investigate whether there may also be genotypic variation in the ability to carry out a task, by examining the effect of genotype, as well as caste and age, on the foraging performance of workers of the leaf-cutting ant Acromyrmex subterraneus. Larger ants cut larger fragments of orange-impregnated parafilm, and did so more quickly than smaller ants, whereas older ants also cut larger fragments but were slower to transport them. Most importantly, we found that patrilines within colonies differed significantly in the size of fragment cut, and the speed of cutting and transporting fragments when controlling for both ant size and fragment size in the analyses. Certain patrilines were better foragers, often in multiple ways, whereas other patrilines were significantly worse at foraging. Genotype can therefore affect the ability of social insect workers to carry out tasks as well as their previously shown propensity to engage in them, providing an additional mechanism by which genetic diversity may be beneficial to social insect colonies.

Genetics and Evolution of Social Behavior in Insects

“…Later studies also showed that workers produced by different fathers in honeybee colonies differ in their likelihood of foraging for pollen or nectar, scouting new nest sites, grooming nestmates, guarding the nest, and removing corpses from the colony (16,45,46). Similar differences among patrilines (or matrilines when colonies contain several queens) were reported in many other species of ants (30,42), bees (16), wasps (113), and termites (62).…”

Sperm mixing in the polyandrous leaf‐cutting ant Acromyrmex echinatior

“…; Constant et al. ) or disease resistance (Hughes and Boomsma , ; Hughes et al. ), and such benefits would only be maximized if sperm was completely mixed after storage.…”

Worker senescence and the sociobiology of aging in ants

“…Few studies, however, have attempted to track labor throughout the worker lifespan in ants (Lenoir 1979; Porter and Jorgensen 1981; Schmid-Hempel and Schmid-Hempel 1984; Kwapich and Tschinkel 2013) or measure age-specific task efficiencies (Muscedere et al 2009, 2013; Robinson et al 2009; Amador-Vargas 2012; Constant et al 2012). Recent studies on the completely dimorphic Pheidole dentata indicate that newly eclosed workers are not behaviorally mature and that age-related myological, neuroanatomical, and neurochemical changes underscore the ability of workers to labor productively (Muscedere et al 2009, 2011, 2012).…”