Biology subjects

Gharpure, G.

Publications and source records attributed to Gharpure, G..

3 recordsLinked to original sources

bioRxiv2025

Consistency in floral volatiles impacts plant-pollinator interactions in the face of environmental change in the Eastern Himalayas

Floral scents are an important mediator of many plant-pollinator interactions. However, environmental and ecological change could affect the synthesis and emission of volatile chemicals that constitute floral scents, potentially influencing pollinator perception of scents. We investigated the effects of elevation and warming on the floral scents of multiple co-occurring alpine meadow plant species along an elevational gradient in the Eastern Himalayas (3000 - 4000 masl). We also investigated pollinator responses in the same locations using 3-D printed floral models that replicated the differing volatile constituents. Finally, we assessed how pollinator preferences changed with variations in elevation, flowering season and location. We found that elevation and in-situ warming using Open Top Chambers (OTC) led to significant intraspecific variation in the composition of floral scents, both in terms of quality and quantity of volatiles released. Nevertheless, conspecific floral scents across elevations were more similar to each other than to other species. Cafeteria assays using artificial floral models revealed that pollinator preferences were driven by a small number of volatiles (p-cymene, 2-pentylfuran and -pinene), but these preferences were abolished in a novel plant-pollinator community where the same floral volatiles were not detected. Our results suggest that the local odourscape established by the floral community present plays a key role in plant-pollinator interactions. This emphasizes the need to incorporate ecological impacts such as changes in community into climate change analyses to understand the long-term impacts of human activity on co-evolutionary relationships like pollination. Significance StatementFloral scents are important for most plant-pollinator interactions, and can be affected by environmental factors like elevation and temperature. Our study shows that elevation and simulated in situ warming change the composition of floral scents, yet scents from the same species were more similar to each other across elevations and temperatures than to other species. Further, pollinator preferences to these scents replicated in artificial models persisted in spite of variation in temperature and elevation, but not in a novel plant-pollinator community containing floral species not releasing those volatiles. This emphasizes the need to incorporate factors such as floral community composition into our understanding of the long-term impacts of climate change and human activity on co-evolutionary relationships like pollination.

ecology↗

bioRxiv2024

Surviving in the mountains: Temperature and elevation have contrasting physiological effects on the hoverfly Eristalis tenax in the Himalayas

Insect populations are experiencing a global decline due to a variety of human-linked environmental changes. Among these changes, how insects physiology might be affected by predicted upslope migration due to climate change is unknown. Being ectotherms, insect physiology is impacted by abiotic factors like ambient temperature that change with elevation. Here, we performed in situ experiments to assess the sensory and cardiac physiology of an important generalist pollinating hoverfly Eristalis tenax (Diptera: Syrphidae), across different elevations in the eco-sensitive and biodiverse Himalayan mountains. We built a portable physiology setup and measured hoverfly antennal responses towards common floral volatiles at 3600 masl and 4200 masl. We also recorded their heart rate at 3000 masl, 3500 masl and 4000 masl. We report the first in situ physiology experiments performed in the high-altitude Himalayas. Our results show a contrasting impact of elevation and temperature on the sensory and cardiac physiology of hoverflies, with antennal sensitivity decreasing with increasing elevation, while average heart rate increased with temperature, independent of elevation. With upslope migration and climate warming, consequent sensory mismatches and cardiac stress could have deleterious effects on the health of both hoverflies and the vulnerable Himalayan ecosystem.

zoology↗

bioRxiv2024

Extinction of innate floral preferences in the pollinator Eristalis tenax

Innate behaviors allow solitary animals to complete essential tasks in the absence of social learning. However, we know little about the degree to which ecologically relevant innate preferences can change. The hoverfly Eristalis tenax, a solitary generalist pollinator, is an ideal model for studying innate behavior in a naturalistic context because its survival depends on the innate ability to identify flowers. Innate behavior in E. tenax has previously been considered inalterable, but we hypothesized that E. tenax can modulate their innate behavior after training in a multimodal sensory context, in contrast to the prior work that employed unimodal sensory cues. To test this, we examined if E. tenax can extinguish an innate proboscis extension response (PER) to a multimodal floral object after undergoing aversive conditioning with quinine, and if flies can acquire PER to an innately unattractive object using sucrose as reinforcement. Finally, we assessed long-term memory retention. Here, we report a complete extinction of the proboscis extension response (PER) to an innately attractive floral object following aversive training. E. tenax can also acquire PER to an innately unattractive object after appetitive training. Flies can retain these memories for days after training, and aversive memories last longer than appetitive memories. Our results contrast with literature stating that innate preferences cannot be extinguished in E. tenax. This could be because our study uses multimodal objects instead of the unimodal stimuli used in previous work. Ultimately, these findings improve our understanding of how animals navigate the uncertainties of dynamic objects in the natural world.

animal behavior and cognition↗