Resolution and sensitivity of the eyes of the Asian honeybees Apis florea, Apis cerana and Apis dorsata

Abstract

SUMMARYBees of the genus Apis are important foragers of nectar and pollen resources. Although the European honeybee, Apis mellifera, has been well studied with respect to its sensory abilities, learning behaviour and role as pollinators, much less is known about the other Apis species. We studied the anatomical spatial resolution and absolute sensitivity of the eyes of three sympatric species of Asian honeybees, Apis cerana, Apis florea and Apis dorsata and compared them with the eyes of A. mellifera. Of these four species, the giant honeybee A. dorsata (which forages during moonlit nights) has the lowest spatial resolution and the most sensitive eyes, followed by A. mellifera, A. cerana and the dwarf honeybee, A. florea (which has the smallest acceptance angles and the least sensitive eyes). Moreover, unlike the strictly diurnal A. cerana and A. florea, A. dorsata possess large ocelli, a feature that it shares with all dim-light bees. However, the eyes of the facultatively nocturnal A. dorsata are much less sensitive than those of known obligately nocturnal bees such as Megalopta genalis in Panama and Xylocopa tranquebarica in India. The differences in sensitivity between the eyes of A. dorsata and other strictly diurnal Apis species cannot alone explain why the former is able to fly, orient and forage at half-moon light levels. We assume that additional neuronal adaptations, as has been proposed for A. mellifera, M. genalis and X. tranquebarica, might exist in A. dorsata.

Hornets Can Fly at Night without Obvious Adaptations of Eyes and Ocelli

“…An optical sensitivity similar to that found in V. crabro (0.14 µm 2 sr) is found in diurnal bees ( Apis mellifera , 0.1), in humans (0.1; for review see [24]), and also in two large bee species that are normally diurnal but are able to forage on moonlit nights: A. dorsata , the Asian giant honeybee [8], and X. tenuiscapa , a large Indian carpenter bee [7]. Both species also have narrow rhabdoms and small acceptance angles, similar to V. crabro , and while interommatidial angles are not known for A. dorsata , those of X. tenuiscapa are as small as those of V. crabro [7].…”

Street lighting changes the composition of invertebrate communities

“…Yet, there is only limited understanding of the impact that light pollution has on the structure and functioning of ecosystems. Many organisms have evolved to take advantage of natural light regimes in terms of intensity [3,4], periodicity [5,6] and spectral characteristics [7,8]. Artificially illuminating the nocturnal environment changes the predictability of these regimes, potentially affecting foraging, navigation, communication and the regulation of daily and seasonal cycles in a plethora of species [9,10].…”

Sex and Caste-Specific Variation in Compound Eye Morphology of Five Honeybee Species

“…ants [21], [22], bees [13], [17]–[19], [23], [24] and wasps [25]) document the relation between the structure of the visual system and the specific light environment in which the animal is active. In a recent study, Somanathan et al [24] document visual adaptations of honeybee workers in three Asian species and the Western honeybee and discuss the implications of the eye design in the context of photic niche utilization for foraging. Temporal niche partitioning in honeybees is further important in the context of mating.…”