Antennal asymmetry is not associated with social behaviour in Australian Hymenoptera

Abstract

Lateralisation of biological form and function are well known for vertebrates and are being increasingly documented among invertebrates in recent years. Behavioural lateralisation in insects, together with asymmetrical distributions of antennal sensilla, has been linked to the communication challenges faced by social, but not solitary, insects. Recent evidence on patterns of asymmetry in insects outside of the Hymenoptera suggests that this explanation for antennal sensilla asymmetry may not be phylogenetically constrained. We explore this possibility by examining the distribution of antennal sensilla in three species of ants (Formicidae), the meat ant Iridomyrmex purpureus (Dolichoderinae), the green tree ant Oecophylla smaragdina (Formicinae) and the shield ant Meranoplus sp. (Myrmicinae) in which colony organisation is eusocial, and two species of nomiine bees, Mellitidia tomentifera and Reepenia bituberculata (Halictidae: Nomiinae), where colony organisation is not eusocial. Our results demonstrate that while there are differences in the left-right asymmetry of antennal sensilla basiconica in workers of the formicine ant I. purpureus, there is no consistent sensilla asymmetry across the five species. We find a negative correlation between antennal sensilla density and body size in R. bituberculata, which was not apparent in the other species. Our results contradict the suggestion that asymmetrical distribution of antennal sensilla is associated with the evolution of eusocial behaviour.

Morphometric comparisons and novel observations of diurnal and low-light-foraging bees

“…Tierney pers. comm., cited in Freelance et al (2019)) and records of the species being collected at light traps (PaDIL registration number 57995: http://www.padil.gov.au/pollinators/pest/specimens/138403) there is no formal documentation of the species actually foraging in low-light conditions.…”

Antennal Sensilla in Vespidae: A Comparison Between a Diurnal and a Nocturnal Polistinae Wasp

“…This lateralization has been reported in the honeybee A. mellifera regarding olfactory function (Rogers & Vallortigara, 2008; Rigosi et al, 2011) learning (Letzkus et al, 2006; Anfora et al, 2010), and memory (Rogers & Vallortigara, 2008; Frasnelli et al, 2010 a ), in the bumblebee B. terrestris (Anfora et al, 2011), and stingless bees regarding olfaction (Frasnelli & Vallortigara, 2017). However, the association of neural lateralization with asymmetrical distribution of sensilla in the antennae has been discussed since it occurs in honey bee (Frasnelli et al, 2010 b ) and bumble bee (Anfora et al, 2011) but not in the solitary bees Osmia cornula (Anfora et al, 2010), Osmia rufa (Frasnelli & Vallortigara, 2017), Mellitidia tomentifera, and Reepenia bituberculata (Freelance et al, 2019). On the other hand, differences in the number and types of olfactory sensilla and non-olfactory sensilla between the antennae have been reported for A. mellifera (Frasnelli et al, 2010 b ), B. terrestris (Anfora et al, 2011), the stingless bee Austroplebeia australis (Frasnelli & Vallortigara, 2017), and the ant Iridomyrmex purpureus (Freelance et al, 2019).…”

“…However, the association of neural lateralization with asymmetrical distribution of sensilla in the antennae has been discussed since it occurs in honey bee (Frasnelli et al, 2010b) and bumble bee (Anfora et al, 2011) but not in the solitary bees Osmia cornula (Anfora et al, 2010), Osmia rufa (Frasnelli & Vallortigara, 2017), Mellitidia tomentifera, and Reepenia bituberculata (Freelance et al, 2019). On the other hand, differences in the number and types of olfactory sensilla and non-olfactory sensilla between the antennae have been reported for A. mellifera (Frasnelli et al, 2010b), B. terrestris (Anfora et al, 2011), the stingless bee Austroplebeia australis (Frasnelli & Vallortigara, 2017), and the ant Iridomyrmex purpureus (Freelance et al, 2019). Here, the characteristics of the antennal sensilla in the wasps indicate that the functions of the coeloconic are to detect temperature and humidity (Keil, 1999;Sevarika et al, 2021), the basiconic-types 1 and 2 contact chemoreceptor (gustatory) (Altner & Prillinger, 1980) and trichoid-type 1 mechanoreceptor (McIver, 1975).…”