Individual experience influences reconstruction of division of labour under colony disturbance in a queenless ant species

Abstract

Background Division of labour (DOL) is ubiquitous across biological hierarchies. In eusocial insects, DOL is often characterized by age-related task allocation, but workers can flexibly change their tasks, allowing for DOL reconstruction in fluctuating environments. Behavioural change driven by individual experience is regarded as a key to understanding this task flexibility. However, experimental evidence for the influence of individual experience is remains sparse. Here we tested the effect of individual experience on task choice in the queenless ponerine ant, Diacamma cf. indicum from Japan. Results We confirmed that both nurses and foragers shifted to vacant tasks when the colony composition was biased to one or the other. We also found that nurses which are induced to forage readily revert to nursing when reintroduced into balanced colonies. In contrast, foragers which are induced to revert to nursing very rarely return to a foraging role, even 19 days post reintroduction to their original colony. Conclusions Taken together, our results suggest that individual experience decreases the response threshold of original foragers, as they continue to be specialist nurses in a disturbed colony. However, original nurses do not appear strongly affected by having forager experience and revert to being nurses. Therefore, while individual experience does have an effect, other factors, such as reproductive ability, are clearly required to understand DOL maintenance in fluctuating environments.

Context‐dependent expression of variation in defensive behaviour in the lower termite Zootermopsis nevadensis

“…It should also be noted that the age‐related task allocation could contribute to the colony maintenance under variable environments in the termite Coptotermes formosanus (Lee et al, 2022). Each individual experiences different tasks in the process of ageing, and the individual behavioural differences and resulting task allocation could be determined through individual experiences in some ants (Stroeymeyt et al, 2011; Tanaka et al, 2022). We used individuals with similar body sizes collected from the colony at the identical timing, but ages and experiences could not be unified between paired individuals.…”

“…One possible explanation is that defensive decision‐making may be determined by sex and/or size differences between intracolonial members. Other intrinsic factors are thought to be the individual ages and experiences in some ants and termite (Lee et al, 2022; Stroeymeyt et al, 2011; Tanaka et al, 2022; Yanagihara et al, 2018). In contrast, the encounter has the advantage of colony defence from intruders at the narrow entrance in lower termites (Yanagihara et al, 2018).…”

Dominance hierarchy limits resilience in the endangered queenless ant Dinoponera lucida

“…Task choice and degree of specialisation can be in uenced by many factors and the process of division of labour is not to this day fully understood (review in Beshers and Fewell 2001). Genetic (Kohlmeier et al 2019), physiological (Leitner and Dornhaus 2019;Robinson 2009) and social/environmental factors (Tripet and Nonacs 2004;Ravary et al 2007;Tanaka et al 2022), as well as age (Wakano et al 1998;Hölldobler and Wilson 1990) and morphology (Grzes et al 2016; Kamhi et al 2015) in uence division of labour. Many of these factors are interconnected, with nurses being the youngest, most corpulent and most fertile when compared with foragers (Féneron et al 1996;Robinson et al 2009;Tanaka et al 2022).…”

“…Genetic (Kohlmeier et al 2019), physiological (Leitner and Dornhaus 2019;Robinson 2009) and social/environmental factors (Tripet and Nonacs 2004;Ravary et al 2007;Tanaka et al 2022), as well as age (Wakano et al 1998;Hölldobler and Wilson 1990) and morphology (Grzes et al 2016; Kamhi et al 2015) in uence division of labour. Many of these factors are interconnected, with nurses being the youngest, most corpulent and most fertile when compared with foragers (Féneron et al 1996;Robinson et al 2009;Tanaka et al 2022). These ants have a high work potential and/or reproductive value for the colony and generally begin their lives in low-risk tasks, transitioning to more risky tasks as they age (Beshers and Fewell 2001).…”

“…Workers' ability to express behavioural plasticity in executing tasks is well-known for ants (Seid and Traniello 2006;Robinson et al 2009;Bernadou et al, 2015;Tanaka et al 2022). The probability of switching tasks varies across species and between behavioural subcastes.…”