A hard day’s night: Patterns in the diurnal and nocturnal foraging behavior of Apis dorsata across lunar cycles and seasons

Abstract

The giant honey bee Apis dorsata is unusual in being able to forage during both the day and the night. To date, the extent of this unique nocturnal foraging behavior and the environmental factors correlating with it have not been deeply investigated. We conducted the first systematic investigation into the nocturnal behavior of A. dorsata in Southern India by tracking the daily and nightly foraging activity of A. dorsata colonies in an urban environment for 8 months, over multiple seasons and lunar cycles. We found strong evidence that A. dorsata can behave in a manner that is “cathemeral” (active over the entire diel cycle) when environmental illumination is sufficient for nocturnal flight. However, workers were not always active even when the environment should have been bright enough for them to forage, suggesting that their nocturnal foraging behavior was also affected by seasonal changes in resource availability. The foraging activity observed during the day versus twilight versus night differed between seasons; notably, nocturnal activity rates were higher than diurnal activity rates during the winter. We found that at our study site A. dorsata routinely exhibits both diurnal and crepuscular activity, foraging just as intensely during the short twilight hours as during the day. The high foraging activity observed during the twilight and nighttime hours shows that A. dorsata colonies can extend their foraging beyond the daylight hours and reveals that foraging during these dimly lit hours is an integral part of their foraging ecology. This evidence of the importance of nocturnal and crepuscular foraging by A. dorsata paves the way for future studies examining the role of this species in nocturnal pollination networks, the contribution of nocturnal foraging to colony-level nutrition and energy budget, and the evolution of this unusual behavior. Future work comparing nocturnal activity in light polluted urban environments versus unpolluted natural environments is particularly encouraged to determine the generalizability of these findings.

Dim-light colour vision in the facultatively nocturnal Asian giant honeybee, Apis dorsata

“…The foraging activity of A. dorsata workers across the four lunar quarters during our experiments are denoted by the light grey horizontal bars and the nocturnal period is denoted by the black areas. Nocturnal activity was observed only at IISc Bengaluru, although earlier studies [38,39] have reported nocturnal activity at UAS-GKVK Bengaluru (dark grey bars with dotted-white outline). Night activity in A. dorsata has also been observed at Kaigal (by Kavya Mohan; cross), at Sirsi (diamond; [34]) and at Bhimashankar (plus symbol; [35]).…”

“…The European honeybee Apis mellifera cannot use colour cues at light levels comparable to half-moon intensities [32,61], and cease their activity around sunset. However, the Asian giant honeybee Apis dorsata [34,38] and the African honeybee Apis mellifera adansonii [33,62] facultatively extend foraging activity into the night [33][34][35]38]. While A. dorsata has larger eyes and ocelli compared to sympatric honeybees (A. cerana, A. florea) and A. mellifera [35], their physiological and neural adaptations for nocturnal vision, and the role of these adaptations in processing colour information in dim light, remain unknown.…”

“…During training the sucrose reward was presented on a small [38,39] have reported nocturnal activity at UAS-GKVK Bengaluru (dark grey bars with dotted-white outline). Night activity in A. dorsata has also been observed at Kaigal (by Kavya Mohan; cross), at Sirsi (diamond; [34]) and at Bhimashankar (plus symbol; [35]).…”

Giant honeybees (Apis dorsata) trade off defensiveness against periodic mass flight activity

“…Therefore, in the example of the episode mfa 1 the status of quiescence (nMFA) can be assigned for surveillance zones with the exception of the mouth zone (sz 1-3,5 ) for the session nP d 1 before MFA started, and also for the sessions after the termination of MFA, nP d 9–17 with odd counts ( Fig 4A ). The status of the mouth zone (sz 4 ) is non-quiescent due to the locomotor activities as long the mouth zone exists during the day (sometimes the giant honeybees collect nectar and pollen even at night time [ 60 , 61 ]). Non-quiescence in the surveillance zones, which are peripheral to the mouth zone, is formally characterized by two criteria: firstly, by the occurrence of shimmering behavior in response to the presentation of the dummy wasp, which happens in the P d sessions predominantly in nMFA state; and secondly, the colony-specific disorder of nestmates during MFA, which affects all zones and layers of the bee curtain, even on both sides of the nest.…”

New genome reveals molecular signatures of adaptation to nocturnality in moth-like butterflies (Hedylidae)

“…For animals, this cycle represents a critical temporal framework within which they conduct their activities. A clear dichotomy often exists between diurnal (day-active) and nocturnal (night-active) animals, with many insects 3,4 , birds 5 and mammals 6 restricted to either of the activity periods, often called diel-niche. While binning into nocturnal and diurnal categories is a simplification, given that animals occupy varied activity periods, this allows the examination of diel patterns and how lifestyles shift over an evolutionary time scale 7,8 .…”