Kin recognition in social insects and other animals—A review of recent findings and a consideration of their relevance for the theory of kin selection

Abstract

Kin selection is a widely invoked mechanism to explain the origin and evolution of social behaviour in animals. Proponents of the theory of kin selection place great emphasis on the correlation between asymmetries in genetic relatedness created by haplodiploidy and the multiple origins ofeusociality in the order Hymenoptera. The fact that a female is more closely related genetically to her full sister than to her daughters makes it more profitable for a Hymenopteran female, in terms of inclusive fitness, to raise full sisters rather than daughters or full siblings with a female biased sex ratio rather than offspring. This is sometimes referred to as the haplodiploidy hypothesis. In reality however, genetic relatedness between workers in social insect colonies and the reproductive brood they rear is far below ()75, the value expected for full sisters, often below (}5 the value expected between mother and daughter and, not uncommonly, approaching zero. Such values are on account of queen turnover, multiple mating by queens or polygyny. This situation raises doubts regarding the haplodiploidy hypothesis unless workers can discriminate between full and half sisters and preferentially direct their altruism towards their full sisters only. This would still mean an effective coefficient of genetic relatedness of(}75 between altruist and recipient. For this to be possible however, workers should be able to recognise their full sisters inspite of growing up with and being habituated to an assortment of full sisters, half sisters and perhaps other even less related individuals. Even outside the Hymenoptera, social animals may find themselves growing up together in the company of individuals ofvarying degrees of relatedness. An ability to tell apart the more and less related individuals under such circumstances should favour kin selection.Much effort is now going into assessing the abilities of animals to discriminate between kin and non kin. In every case studied carefully so far, animals appear to be capable of recognising their kin. Ants, wasps, sweat bees, honey bees, frogs, toads, mice, rats, voles, squirrels, monkeys and even humans appear to be able to recognise their kin in one circumstance or another. An ability to recognize true genetic relatedness requires genetically specified recognition labels and these must therefore be present. Recent findings of the role of the histocompatibility system provides some clues to the possible nature of recognition labels. An ability to recognise full sisters for example, inspite of being habituated to full and half sisters requires not merely genetically specified labels but also recognition templates which are based on the characteristics of the individual animals making the recognition and not templates based on all animals one grows up with. Some animals such as honey bees, tadpoles and ground squirrels appear to have such templates but others such as sweat bees and some mice appear not to. It is entirely possible that our inability to devise natural enough assays for recogn...

Factors affecting the acceptance of alien conspecifics on nests of the primitively eusocial wasp,Ropalidia marginata (Hymenoptera: Vespidae)

“…The proximate explanation for the decreasing probability of acceptance, increasing aggression, and decreasing tolerance shown by the resident wasps toward the introduced wasps may have to do with the gradual development of recognition labels by the introduced wasps (Gadagkar, 1985;Gamboa et al, 1986;Waldman, 1988;Singer and Espelie, 1992). The fact that their ovarian condition does not appear to influence directly their probability of acceptance suggests that the developing ovaries are not the sole source of the recognition template.…”

“…A fundamental feature of social insect colonies is the discrimination between nestmates and nonnestmates so that colonies can readily accept returning nestmates and keep away nonnestmates, thus maintaining colony integrity (Gadagkar, 1985;Gamboa et al, 1986). The first few days of adult life, referred to as the "sensitive period," in social insects may be crucial for individuals to integrate into their colony.…”

Kin recognition inDrosophila: the importance of ecology and gut microbiota

“…Kin recognition in D. subobscura is not based on familiarity as common environment, and thus repeated interactions between familiar larvae had no effect on copulation duration. Consequently, kin recognition in this species is likely based on phenotype matching, a process allowing the recognition of unfamiliar but related individuals (Gadagkar, 1985;Waldman, 1987;Waldman et al, 1988;Hepper, 1991;Holmes, 2004).…”

Diet-Mediated Pheromones and Signature Mixtures Can Enforce Signal Reliability

“…Kin odor-based recognition, in particular, are thought to facilitate inbreeding avoidance or altruistic behavior (see Gadagkar, 1985), while maternal and offspring odor-based recognition are more likely to evolve in altricial and/or colonial species.…”