Ontogeny of Nestmate Recognition in Social Hymenoptera

Abstract

The ability to discriminate between friends and foes is a central feature of social life. In social insects, nestmate recognition is mediated by colony specific cuticular hydrocarbons (CHCs) (label) that are perceived by an individual and compared with its neural representation of the colony odour (template). Although numerous advances have been made in understanding the identity, origin and production of recognition cues in social hymenoptera, relatively little is known about the ontogeny of nestmate recognition, and the learning processes that might be involved. It appears that wasps and bees learn the recognition cues required for template formation from their nest/comb odour, while ants learn principally from their nestmates. In general, the referent template is learned during the early stages of adult life, although pre-imaginal learning might play a role. The CHC blend can change over time; cue-exchange among nestmates is therefore needed to reduce chemical variability among individuals and to integrate environmental compounds into the colony odour. As a result of this process, the referent template is updated during life. This relative plasticity of the recognition system can be exploited by insect social parasites to integrate themselves within the host colonies and to fool host workers about their real identity. By studying the chemical integration strategies of social parasites new insights on the ontogeny of nestmate recognition could be acquired. However, further studies are needed to reveal the neural substrates implicated in learning and memory at different stages of social insect life to better understand how and when template formation occurs.

Sight in a Clique, Scent in Society: Plasticity in the Use of Nestmate Recognition Cues Along Colony Development in the Social Wasp Polistes dominula

“…On the contrary, small pre-emergence colonies show a higher heterogeneity, with wider variation in the physiological status of foundresses (Pardi, 1946(Pardi, , 1948Röseler et al, 1980;Röseler, 1991) and relatedness (Queller et al, 2000;Leadbeater et al, 2011), all factors that are known to affect CHC individual profile (Bonavita-Cougourdan et al, 1991;Sledge et al, 2001;Dapporto et al, 2004bDapporto et al, , 2005. The colonial chemical signature is the product of a template shared by all individuals thanks to social interactions (contacts, trophallaxis) and through the nest material (Signorotti et al, 2015). It is likely that the more homogeneous conditions of late-season colonies allow the production of a more marked and reliable colonial chemical signature, while in pre-emergence colonies, individual level heterogeneity might somehow reduce inter-colony differences in the chemical profile.…”

“…This implies that age (foundresses are several months old, while workers are only days/weeks old) or caste-related differences (foundresses are reproductive individuals while workers are not) could have played a role. While we believe that age is unlikely to have an influence, as Polistes wasps are able to perform NMR within a few hours after emergence (thus well before the time at which they were tested) (reviewed in Signorotti et al, 2015), we cannot discard the hypothesis of differences between castes in the NMR system as it has been shown in a social bee (Wittwer and Elgar, 2018). Previous studies offered mixed evidence for the related species Polistes fuscatus: one study documented differences in recognition between queens and workers (with queens having a more restrictive acceptance threshold than workers against unrelated conspecific intruders; Fishwild and Gamboa, 1992), while a more recent experiment found no evidence of such a queen-worker variation in recognition (with workers showing similar ability in familiar recognition compared to queens; Injaian and Tibbetts, 2014).…”

“…NMR occurs through a process of phenotype matching that involves the perception of a label carried by encountered individual and the comparison of this label with an internal reference (template), i.e., a neural representation of the trait stored within the evaluator peripheral and central nervous system (Crozier and Pamilo, 1996;Leonhardt et al, 2007;d'Ettorre and Lenoir, 2009;Signorotti et al, 2015). The response of the evaluator depends on how well the label matches the template (van Zweden and d 'Ettorre, 2010), with the aggressive response triggered when the mismatch exceeds a certain threshold (Reeve, 1989).…”

Social intolerance is a consequence, not a cause, of dispersal in spiders

“…In spiders, the expression of tolerant behaviors requires the processing of chemical information as evidenced, for example, in the wolf spider Geolycosa turricola where spiderlings with impaired chemoreception perform more aggression than do untreated individuals [61]. In the highly integrated colonies of ants, the social isolation of workers impairs nestmate recognition because of a partial loss of the internal template used to discriminate nestmates from non-nestmates [62,63]. Here, the analysis of the chemical signatures of spiderlings revealed similar profiles between spiderlings raised alone or in groups, which strongly suggested that social isolation influenced the processing, not the emission, of social cues.…”

Rethinking recognition: social context in adult life rather than early experience shapes recognition in a social wasp

“…A social group is usually a highly complex environment, which can change over time in both the composition and social role of their members, and recognition processes appear to be finely entwined with the social network of interactions that an individual experiences through its life [42,43]. Given the plasticity in the structure of many social environments [44][45][46], it may be evolutionarily advantageous that group members should reflect a certain degree of plasticity in their recognition system, with the ability to adjust or update their templates based on contextual contingencies [42,43,47]. For example, in many social insect species, the colony odour is dynamic and can change over time owing to multiple factors (i.e.…”