Research Projects

The perception and processing of ambient light and signals in animals aids a plethora of functions including inter- and intra-specific communication [1–4], foraging [5], navigation [6], and regulating circadian activity patterns [7]. Consequently, variation in visual capabilities can shape an organism’s ecological niches and evolutionary trajectories [8]. These visual capabilities are mediated by a diversity of eye structures and opsins that aid in varied light environments and colour discrimination [9,10]. Insects—a large, ecologically relevant group—rely on vision and possess eyes equipped with diverse adaptations that facilitate colour and light perception. Studies across insect taxa have shown that opsins are key molecular players in visual adaptation, often responding to ecological factors such as light environment [8] and behavioural demands [10,11]. However, the functional characterisation of opsins is understudied in tropical pollinator species such as bees. Bees offer a compelling system to investigate visual evolution because they exhibit diversity in diel activity (diurnal to crepuscular and even nocturnal) and social organization (eusocial to solitary)—traits likely to exert selective pressures on their visual systems. Previously, eye morphological adaptations have been explored in association with diel activity [9]. Here, we aim to explore how opsin gene expression and evolution varies across bee species with divergent sociality and diel activity, and whether these differences represent molecular adaptations to ecological light niches. This project will compare opsin gene expression and evolution across three species of Apis (eusocial and primarily diurnal) and three species of Xylocopa (solitary and ranging from diurnal to nocturnal). We hypothesize that variation in diel activity and degree of sociality influences opsin expression patterns, such that bees active in lower light (e.g., Xylocopa) show increased relative expression of long-wavelength opsins [12], while diurnal species maintain broader opsin expression. Further, we predict that social bees, which are primarily active in high-light ambient environments, maintain more balanced expression across opsin types compared to solitary species. Selection analysis will also highlight whether opsins are under positive selection. To test these hypotheses, the project will involve collection of adult foragers of the six bee species across their habitat range and day-length. Followed by dissection of eyes and extraction of total RNA to quantify opsin gene expression (UVRh, BRh, GRh) using qRT-PCR, and RNA sequencing. Finally, we will perform comparative expression analysis across species and in relation to diel activity and social structure, along with selection tests on opsin genes. The results will demonstrate how gene evolution and expression modulation of sensory systems may underlie adaptation to light environments and sociality.