Socially peaceful: foragers of the eusocial bee Lasioglossum malachurum are not aggressive against non-nestmates in circle-tube arenas

Abstract

Due to the universally found nestmate recognition in eusocial insects, it is predictable that non-nestmates interact aggressively. In sweat bees (Hymenoptera: Halictidae), this trend was largely shown for queen-queen interactions, but data on worker-worker interactions are still scarce and somehow controversial. We studied behavioural interactions between foragers of the eusocial and ground-nesting bee Lasioglossum malachurum within circle-tubes. Independently of colony membership, bees exhibited high frequencies of cooperative behaviours, together with lack of aggression and moderate avoidance of social interactions. The cooperative mutual passing was the most frequently recorded behaviour. Size difference between the opponents had no effects on cooperation or avoidance. In a heterospecific experiment, bee foragers were observed to react more aggressively and to pass very rarely towards cuckoo bees, suggesting that our results were not biased by the circle-tube methodology. Our results and comparisons with other bee species suggest that studying worker interactions may be not enough to predict the social organisation in bees. Whatever the evolutionary meaning of this generalised tolerance towards conspecifics, the present findings are somehow in agreement with recent studies showing that L. malachurum colonies may have imperfect nestmate recognition and often include a mixture of related and unrelated workers.

Dominant-subordinate social interactions and subordinate behavioral responses in the primitively eusocial sweat bee Augochlora phoemonoe (Hymenoptera: Halictidae)

“…Ritualized aggression is thought to mediate the process of social competition. Information for other social halictids is fragmentary, and in many cases agonistic interactions, or the lack of them, have been observed in circle tube experiments using non-nestmate bees (e. g., Smith and Weller 1989;Pabalan et al 2000;Arneson and Wcislo 2003;Packer 2006;Polidori and Borruso 2012). Interactions within observation nests have been studied in the facultatively eusocial Megalopta genalis in the context of trophallaxis and of the establishment of dominance relationships in early stage nests (Wcislo and Gonzalez 2006;Kapheim et al 2016).…”

The Problems of a Priori Categorisation of Agonism and Cooperation: Circle‐Tube Interactions in Two Allodapine Bees

“…A seeming lack of NM recognition has previously been shown in the eusocial halictine bee Lasioglossum malachurum (Polidori & Borruso ) and in a couple of Apis species, although that latter study looked only at aggressive behaviours and did not look for evidence of cooperation between individuals (Breed et al. ).…”

“…CT studies of two communal andrenids and a eusocial halictine found no distinguishable behavioural differences between NM and NNM interactions (Paxton et al. ; Polidori & Borruso ; respectively). Conversely, species that are largely solitary have displayed clear NM recognition abilities in CT experiments (Wcislo ; Flores‐Prado et al.…”

“…Circle tubes have also been used to explore the differences in behaviour displayed by individuals interacting with either nestmates (NM) or non‐nestmates (NNM; Paxton et al. ; Polidori & Borruso ). The ability to discriminate between familiar and unfamiliar individuals, and react accordingly, also varies among species and social systems.…”

Methods for rearing ground-nesting bees under laboratory conditions

“…Alternatively, circle tube arenas made from sections (e.g. 30-40 cm) of clear plastic tubing (usually polyethylene) and joined at the ends may be useful (see Breed et al (1978), Kukuk and Decelles (1986), Polidori and Borruso (2012)). Compared with other bees, queens spend a significant proportion of their time exhibiting certain behaviours including nudging and backing (Michener and Brothers 1974;Breed and Gamboa 1977;Breed et al 1978).…”