Robert A. Raguso

Overview

I study plant-insect interactions from molecules to ecosystems. I am an integrative and comparative biologist with an interest in the chemical senses. Everything begins with natural history.

Research Focus

Floral scent, the focus of my research, is a key sensory component of plant-pollinator communication, a poorly explored dimension of floral phenotype, and a major chemical expression of biological diversity. I work at the rich biological interface between insects and plants, an important source of terrestrial biodiversity and complex ecological interactions. To a great extent, this richness is manifested in chemistry: the chemistry of defense and resistance, of mimicry and deception, of communication between mutualists, and in physiology; the physiology of signal detection and processing, of sensory integration and its impact on behavior. My training in plant and insect biology reflects my commitment to understanding chemical communication from the standpoints of signal production and detection. Due to technological challenges and historical visual biases among pollination biologists, the study of floral scent remains a biological frontier with unlimited potential for novel research initiatives. Throughout my career, I have dedicated myself to the goal of integrating floral scent into the field of pollination biology, through my own multidisciplinary studies and publication of several review papers, through training students and postdocs in volatile analysis and behavioral bioassays and through organizing and chairing the first Gordon Research Conference in my field.

Publications

• Dahake, A., C. Coates, D. Obregon, J. Chai, P. Nunes-Silva, P. Kevan, R.A. Raguso. 2025. Flowers as microhabitats: floral humidity of squash impacts pollen viability and pollinator behavior. Current Biology 35: 1-17. https://doi.org/10.1016/j.cub.2025.08.039
• Heuel, K.C., R.A. Raguso, E. Coogan, R. Mallick, K.J. Kelleher, M. Ayasse, R.J. Gegear, H. Burger.2025. Spatial partitioning of volatiles in morphologically complex flowers provides a ‘chemosensory roadmap for bumblebee pollinators. Current Biology 35: 1622-1630. https://www.cell.com/current-biology/fulltext/S0960-9822(25)00144-7
• Dahake, A., S. Persaud, M. Jones, J. Goyret, G. Davidowitz, R.A. Raguso. 2024. Dying of thirst: water loss and osmotic rescue in nectar feeding hawkmoths. Journal of Insect Physiology 159: 104700. https://doi.org/10.1016/j.jinsphys.2024.104700
• Balbuena, M-S., S.L. Buchmann, D.R. Papaj, R.A. Raguso. 2024. Conventional or index signals? Floral scent composition in Krameria plants pollinated by specialized oil-collecting bees. Phytochemistry 218: 113937. https://www.sciencedirect.com/science/article/pii/S0031942223003539
• Diaz-Martin, Z., A. Cisternas, K.M. Kay, R.A. Raguso, K.A. Skogen, J.B. Fant. 2023. Shifts in reproductive strategies and their consequences for gene flow and genetic diversity. Heredity https://doi.org/10.1038/s41437-023-00649-y
• Raguso, R.A. 2023. Hidden worlds within flowers. Current Biology 33: R506-R512. https://www.cell.com/current-biology/fulltext/S0960-9822(23)00536-5
• Salzman, S., A. Dahake, W. Kandalaft, W. Valencia-Montoya, M. Calonje, C. D. Specht, R.A. Raguso. 2023. Cone humidity is a strong attractant in an obligate cycad pollination system. Current Biology 33: 1-11. https://www.cell.com/current-biology/fulltext/S0960-9822(23)00309-3
• Dahake, A., P. Jain, C. Vogt, W. Kandalaft, A. Strook, R.A. Raguso. 2022. A signal-like role for floral humidity in a nocturnal pollination system. Nature Communications 13: 7773. https://www.nature.com/articles/s41467-022-35353-8
• Contreras, H., J. Goyret, C.T. Pierce, R.A. Raguso, G. Davidowitz. 2022. Eat, drink, live: foraging behavior of a nectarivore when food resources are limited and ambient humidity is varied. Journal of      Insect Physiology 143: 104450. https://doi.org/10.1016/j.jinsphys.2022.104450
• Skogen, K.A., T. Jogesh, E.T. Hilpman, S.L. Todd, R.A. Raguso. 2022. Extensive population-level sampling reveals clinal variation in (R)(-)-linalool produced by the flowers of an endemic evening primrose, Oenothera harringtonii. Phytochemistry 200: 113185. https://doi.org/10.1016/j.phytochem.2022.113185
• Balbuena, M-S., G.T. Broadhead, A. Dahake, E. Barnett, M. Vergara, K.A. Skogen, T. Jogesh, R.A. Raguso. 2022. Mutualism has its limits: consequences of asymmetric interactions between a well- defended plant and its herbivorous pollinator. Philosophical Transactions of the Royal Society 377:20210166. https://doi.org/10.1098/rstb.2021.0166
• Eisen, K.E., M.A. Geber, R.A. Raguso. 2022. Emission rates of species-specific volatiles vary across communities of Clarkia species: evidence for multi-modal character displacement. The American Naturalist 199: 824-840. https://www.journals.uchicago.edu/doi/full/10.1086/715501
• Eisen, K.E., J.M. Powers, R.A. Raguso, D.R. Campbell. 2022. An analytical pipeline to support robust research on the ecology, evolution and function of floral volatiles. Frontiers in Ecology and Evolution: 10: 1006416. https://doi.org/10.3389/fevo.2022.1006416
• Broadhead, G.T., R.A. Raguso. 2021. Associative learning of non-sugar nectar components: amino acids modify nectar preference in a hawkmoth. Journal of Experimental Biology 224: jeb23463. https://doi.org/10.1242/jeb.234633
• Raguso, R.A. 2021. Coevolution as a cornucopia of biodiversity and ecosystem services. Plants, People, Planet 3: 61-73. https://doi.org/10.1002/ppp3.10127
• Raguso, R.A. 2020. Mini-review. Don't forget the flies: dipteran diversity and its consequences for floral ecology and evolution. Applied Entomology and Zoology (Japan) 55: 1-7. https://link.springer.com/article/10.1007/s13355-020-00668-9
• Bueno, E., K.R. Martin, R.A. Raguso, J.G. McMullen II, S.P. Hesler, G.M. Loeb, A.E. Douglas. 2020. Response of natural populations of Spotted Wing Drosophila (Drosophila suzukii) to microbial volatiles. Journal of Chemical Ecology 46: 688-698. https://link.springer.com/article/10.1007/s10886-019-01139-4
• Friberg, M., C. Schwind, P.R. Guimarães, R.A. Raguso, J.N. Thompson. 2019. Extreme diversification of floral volatiles within and among species of Lithophragma (Saxifragaceae). Proceedings of the National Academy of Sciences, USA 116: 4406-4415. https://www.pnas.org/doi/abs/10.1073/pnas.1809007116
• Kay, K.M., A.M. Zepeda, R.A. Raguso. 2019. Experimental sympatry reveals geographic variation in floral isolation by hawkmoths. Annals of Botany 123: 405-413. https://doi.org/10.1093/aob/mcy143
• Jacobsen, D.J., R.A. Raguso. 2018. Lingering effects of herbivory on pollination. Current Biology 28: R1164-R1169. https://www.cell.com/current-biology/fulltext/S0960-9822(18)31055-8
• Kantsa, A, R.A. Raguso, A.G. Dyer, J.M. Olesen, T. Tscheulin, T. Petanidou. 2018. Disentangling the role of floral sensory diversity in pollination networks. Nature Communications 9: 1041. https://www.nature.com/articles/s41467-018-03448-w
• Kantsa, A, R.A. Raguso, A.G. Dyer, S.P. Sgardelis, J.M. Olesen, T. Petanidou. 2017. Community- wide integration of floral colour and scent in a Mediterranean scrubland. Nature Ecology & Evolution 1:1502-1510. https://www.nature.com/articles/s41559-017-0298-0
• Broadhead, G.T., T. Basu, M. von Arx, R.A. Raguso. 2017. Diel rhythms and sex differences in the locomotor activity of hawkmoths. Journal of Experimental Biology 220: 1472-1480. https://doi.org/10.1242/jeb.143966

In the news

• Student research has CURB appeal