Abstract
Eusocial species exhibit pronounced division of labor, most notably between reproductive and non-reproductive castes, but also within non-reproductive castes via morphological specialization and temporal polyethism. For species with distinct worker and queen castes, age-related differences in behavior among workers (e.g. within-nest tasks versus foraging) appear to result from physiological changes such as decreased lipid content. However, we know little about how labor is divided among individuals in species that lack a distinct queen caste. In this study, we investigated how fat storage varied among individuals in a species of ant (Dinoponera australis) that lacks a distinct queen caste and in which all individuals are morphologically similar and capable of reproduction (totipotent at birth). We distinguish between two hypotheses, 1) all individuals are physiologically similar, consistent with the possibility that any non-reproductive may eventually become reproductive, and 2) non-reproductive individuals vary in stored fat, similar to highly eusocial species, where depletion is associated with foraging and non-reproductives have lower lipid stores than reproducing individuals. Our data support the latter hypothesis. Location in the nest, the probability of foraging, and foraging effort, were all associated with decreased fat storage.
Highlights
Division of labor is a hallmark of eusocial behavior
D. australis colonies did differ in the slope of the relationship between fat content and depth (F4,267 = 3.41, P = 0.01, Fig. 1), but not in head width and depth (F3,231 = 1.53, P = 0.21); we used a separate slopes model to examine differences in fat content across colonies
Our results support the hypothesis that division of labor can be organized by nutritional status, and that fat storage may be a conserved means of organizing foraging behavior even in a species where all individuals are capable of mating and reproducing
Summary
Division of labor is a hallmark of eusocial behavior. In the eusocial Hymenoptera, the primary division of labor is between the reproductive individuals (the queens) and the female work force. Further task subdivisions may exist based either on morphological specialization or age related changes in behavior (temporal polyethism) This division of labor and resulting task allocation can increase colony efficiency, which translates into reproduction and the foundation of daughter colonies [1]. While many factors are known to differ between and within castes such as lifespan [2,3,4,5,6], genetics [7,8,9,10,11,12], and encounter rate [13], among others, variation in fat content is consistently different between queens and workers [14] and is associated with the transition from nest work to foraging in many social insects workers [15]. Toth et al [16] demonstrated a causal link between fat storage and the onset of foraging behavior in honeybees by applying an inhibitor of lipid storage to bees, which increased the likelihood of precocious foraging (though social context was still important)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
