Research Projects

Pollination is important, not just for food security but also for maintaining natural ecosystems. Although most pollination studies focus on daytime pollinators such as bees, nocturnal pollinators are essential for pollen transfer and fruit formation. However, animals pollinating at night face significant challenges, particularly in locating and successfully feeding from host plants despite dim light conditions. Moths are among the major pollinators of plants at night and use plant volatile odor blends to identify and navigate to host plants. Several hawkmoths have excellent scotopic color vision which helps them identify and choose appropriate flowers. As hawkmoths approach flowers, they uncoil their long mouthpart called proboscis and here they face another challenge. They must guide their proboscis precisely into a tiny nectary opening, in dim light condition, even as they hover over flowers that gently sway in the wind. Past research has shown that correctly aligned tactile and visual guides on flowers are essential for their feeding success. Our previous work has shown that moths actively seek surface tactile cues and use it to target the nectary faster. Diurnal hawkmoths also use visual feedback to guide their proboscis to nectary opening. This project will reveal how hawkomths combine feedback from different sensory modalities to guide their appendage, under steady and changing environmental conditions such as light pollution. We hypothesize that hawkmoths can adaptively change their exploration strategy to guide their proboscis tip along which ever cue leads them to the nectary. Using behavioral assays with micro-sensed, 3D printed artificial flowers and high-speed videography, we will quantify the feeding performance and the proboscis and body movements as they feed from different floral surfaces; either with only tactile cues, only visual cues or both simultaneously. We will either present the two cues either aligned to the nectary or misaligned to test if over repeated visits, moths, change the proboscis and body motion to successfully guide their proboscis tip along the sensory cues which leads them to the nectary. Importantly, hawkmoths forage across a wide range of light levels in the natural environment. Increasing light levels decreases visual delays and increases the spatial resolution. Despite this, our previous work shows that at higher light levels, moths have lower feeding success from artificial flowers. We hypothesize that at higher light levels their visual salience increases, such that even in presence of tactile cues which lead them to the nectary, they explore the visually salient floral edges which doesn’t lead to the nectary. The absence of visual cues leading to the nectary opening results in reduced feeding success. We will test this hypothesis by presenting flowers with visual guides at higher light levels and by reducing floral contrast of flowers with tactile cues alone and quantify feeding success. These results will shed light on how animals dynamically change their sensory salience with changing environmental conditions. Importantly these will provide sensory and behavioral mechanisms underlying the effects of human disturbances like light pollution. Finally, we will compare the behavioral control and neural circuitry underlying proboscis motion control across different groups of lepidopterans to ask how natural history and feeding ecology have shaped their behavior and neural circuits. This research across diurnal butterflies, secondarily diurnal and nocturnal hawkmoths will help document the behavior and neural physiology of tropical insect pollinators, data which is especially lacking from the Indian subcontinent, and about nocturnal pollinators which is sparsely documented across the globe. In summary, this project will draw upon tools from engineering to study animal behavior, providing a mechanistic basis of nocturnal pollination and help develop policy to support insect pollination.