About

Robert A. Raguso is a professor in the Department of Neurobiology and Behavior at Cornell University. He is an integrative and comparative biologist with a focus on plant-insect interactions, particularly studying floral scent as a key sensory component of plant-pollinator communication. His research explores the chemistry of floral signals, including defense, resistance, mimicry, deception, and communication between mutualists, as well as the physiology of signal detection and processing and sensory integration impacting behavior. Raguso's work emphasizes natural history and aims to integrate floral scent into pollination biology through multidisciplinary studies, behavioral bioassays, and technological analysis of volatile compounds. He has dedicated his career to understanding chemical communication from the perspectives of signal production and detection, working at the interface of insects and plants, which is a significant source of terrestrial biodiversity and ecological interactions. Raguso has contributed to the field by organizing and chairing the first Gordon Research Conference in his area of study and publishing extensively on topics such as floral humidity, volatile partitioning, and pollination ecology. His research advances knowledge of how floral traits influence pollinator behavior and plant reproductive strategies, emphasizing the importance of chemical signals in ecological and evolutionary contexts.

Research topics

• Biology
• Ecology
• Botany
• Demography
• Evolutionary biology

Selected publications

• Pollination ecology in the tropical Andes: moving towards a cross‐scale approach

  Biological reviews/Biological reviews of the Cambridge Philosophical Society · 2025-07-15

  articleOpen access

  Plant-pollinator interactions structure ecological communities and represent a key component of ecosystem functioning. Pollination networks are expected to be more diverse and specialised in the tropics, but pollination ecology in these regions has been understudied in comparison to other areas. We reviewed research on pollination in the tropical Andes, one of the major biodiversity hotspots on Earth, where the uplift of mountains and past climate have resulted in spatiotemporally distinct species interactions. We found 1010 scientific articles on pollination in the Andes, of which 473 included or were carried out in tropical regions. The number of publications on pollination ecology in the tropical Andes has increased exponentially, with Colombia having the most articles, followed by Ecuador and Peru, and with Bolivia and Venezuela having notably fewer studies. More research has been carried out in humid montane forests and agricultural landscapes, and it has predominantly focused on describing diversity of species and interactions while neglecting analyses on the resilience and adaptability of pollinating systems, even though the Andean region is particularly susceptible to the effects of climate change and continues to undergo land conversion and degradation. Remarkably few studies have incorporated local knowledge, thus ignoring connections to human livelihoods and communities. A phytocentric perspective has been predominant, with fewer studies focusing directly on pollinators and a notable lack of articles with a holistic approach to the study of pollination across taxonomic groups at the community or ecosystem level. We propose that future research adopts a cross-scale approach that considers the complexity of the ecological contexts in which plant-pollinator interactions occur, and incorporates long-term monitoring with broader multilayer networks and molecular tools, experiments focused on ecophysiology and behaviour, animal telemetry, process-modelling approaches and participatory science. A stronger field driven by interdisciplinary collaborations will contribute to knowledge about pollination at a global scale, as well as increase our understanding of the diversity and resilience of pollination interactions in this region, thus improving our capacity to predict and avoid ecosystem collapses.

  PublisherDOI

• Squash flowers as microhabitats: the effects of floral temperature and humidity on pollen viability and visitor behavior

  bioRxiv (Cold Spring Harbor Laboratory) · 2025-02-26

  preprintOpen accessSenior author

  Summary Flowers represent intricate microcosms shaped by their chemical and micrometeorological properties. Notable examples include thermogenic flowers that create a warm microclimate for visitors and residents. We document a distinct microclimate within the large flowers of both wild and domesticated squashes ( Cucurbita spp .). Unlike thermogenic flowers, squash flower temperatures remain near ambient, but their humidity consistently exceeds ambient levels from bud to senescence, resulting from stomatal and petal transpiration rather than nectar evaporation. Experimentally reducing humidity in greenhouse-grown male squash flowers results in significant pollen tube rupture, directly impacting plant fitness. To explore the role of floral humidity within a broader ecological context, we performed similar humidity manipulations on squash farms to assess impacts on the behavior of their specialist squash bee pollinator ( Xenoglossa pruinosa ), generalist pollinators (bumblebees, honeybees), and specialist herbivores (cucurbit beetles). Experimentally reduced floral humidity lower visitation frequency by squash bees but have no effect on generalist pollinators. Manipulation of floral humidity did not influence the foraging duration of any pollinators but impacted the residence of male squash bees in wilted flowers compared with unmanipulated flowers. Finally, there was a positive correlation between the dryness of the ambient air and the abundance of squash bees and cucurbit beetles residing in the humid wilted floral chambers. In conclusion, our findings showcase squash flowers as a humid microhabitat that influences reproductive success directly by affecting pollen viability and indirectly by altering interactions with squash bees, their specialist pollinators.

  PublisherOA PDFDOI

• Spatial partitioning of floral volatiles provides a “chemosensory roadmap” for bumblebee pollinators

  Current Biology · 2025-03-06 · 5 citations

  articleOpen access

  suggest that VOCs might also elicit gustatory responses. Accordingly, we found that bumblebees showed no differential responses to VOCs when encountered as odorants but showed highly differential responses to the same VOCs when ingested with sugar rewards. VOCs present in nectar had agreeable flavors, whereas VOCs of other floral tissues such as nectar spurs were avoided. These findings suggest that VOC partitioning in Impatiens functions as a gustatory preference gradient that encourages legitimate pollination and potentially discourages nectar robbing by bumblebee visitors. Our findings highlight the non-olfactory functions of floral VOCs as flavors or contact chemical stimuli and their potential to structure plant-pollinator networks and filter their interactions with other organisms, including larcenists and other non-pollinating visitors.

  PublisherOA PDFDOI

• The effects of floral microclimate on pollen viability and visitor behavior

  Current Biology · 2025-09-16 · 5 citations

  articleSenior author
  PublisherDOI

• Co-flowering richness has variable effects on pollen quantity and quality limitation in four <i>Clarkia</i> species

  Annals of Botany · 2024-08-12 · 3 citations

  articleOpen access

  BACKGROUND AND AIMS: Pollination failure occurs from insufficient pollen quantity or quality. However, the relative contributions of pollen quantity vs. quality to overall pollen limitation, and how this is affected by the co-flowering context, remain unknown for most plant populations. Here, we studied patterns of pollen deposition and pollen tube formation across populations of four predominately outcrossing species in the genus Clarkia to evaluate how the richness of co-flowering congeners affects the contribution of pollen quantity and quality to pollen limitation. METHODS: We partition variation in pollen deposition and pollen tube production across individuals, populations and species to identify the main sources of variation in components of reproductive success. We further quantify the relative contribution of pollen quantity and quality limitation to the reproductive success of the four Clarkia species using piecewise regression analyses. Finally, we evaluate how variation in the number of co-flowering Clarkia species in the community affects the strength of pollen quality and quality limitation. RESULTS: Across all contexts, pollen deposition and the proportion of pollen tubes produced varied greatly among individuals, populations and species, and these were not always correlated. For instance, C. xantiana received the smallest pollen loads yet produced the highest proportion of pollen tubes, while C. speciosa exhibited the opposite pattern. Yet, co-flowering richness had variable effects on the strength of pollen quantity and quality limitation among populations. Specifically, breakpoint values, which are an indicator of overall pollen limitation, were two-fold higher in the four-species community compared with one- and two-species communities for two Clarkia species, suggesting that pollen limitation can increase with increasing richness of co-flowering congeners. CONCLUSIONS: Our results reveal a complex interplay between the quantity and quality of pollen limitation and co-flowering context that may have different evolutionary outcomes across species and populations.

  PublisherOA PDFDOI

• Dying of thirst: Osmoregulation by a hawkmoth pollinator in response to variability in ambient humidity and nectar availability

  Journal of Insect Physiology · 2024-09-08 · 4 citations

  articleSenior author
  PublisherDOI

• Hidden worlds within flowers

  Current Biology · 2023-06-01 · 6 citations

  articleOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Organ-specific volatiles from Sonoran desert Krameria flowers as potential signals for oil-collecting bees

  Phytochemistry · 2023-11-28 · 2 citations

  articleOpen accessSenior authorCorresponding
  PublisherOA PDFDOI

• Behavior and Feeding of Two Beetle Pollinators of Zamia integrifolia (Cycadales): Rhopalotria slossoni (Coleoptera: Belidae) and Pharaxanotha floridana (Coleoptera: Erotylidae)

  Florida Entomologist · 2023-10-09 · 5 citations

  articleOpen accessSenior author

  Zamia integrifolia L. f. (Cycadales), una cicadácea nativa amenazada en la Florida, depende de 2 especies nativas de escarabajos para la polinización: Rhopalotria slossoni (Chevrolat; Coleoptera: Belidae) y Pharaxanotha floridana (Casey; Coleoptera: Erotylidae). Ambos insectos son mutualistas de la polinización del sitio de cría, y se sabe que viven y se alimentan dentro del cono de polen (macho). Sin embargo, para que ocurra la polinización, los escarabajos también deben visitar conos de ovulación (femeninos), que se supone que no les ofrecen ningún beneficio como alimento o vivero. Probamos el potencial para el uso de conos de ovulación por parte de escarabajos polinizadores, esto mediante la realización de pruebas de alimentación y comportamiento de no elección para adultos de ambas especies de escarabajos tanto en conos de ovulación como en conos de polen de Z. integrifolia. Los escarabajos Rhopalotria slossoni mostraron una mayor sobrevivencia en los tejidos del cono ovulado a pesar de no mostrar diferencias significativas en la masa total de tejido consumido entre los sexos del cono. Por el contrario, P. floridana consumió más masa de tejido de las escamas de los conos de ovulación, pero no mostró diferencias en la sobrevivencia en las escamas de los conos de ovulación frente a las de los conos de polen. Aunque ninguna de las especies de escarabajos se encuentra en grandes cantidades en los conos de ovulación en el campo, nuestro estudio de laboratorio sugiere que ambas especies podrían beneficiarse potencialmente al alimentarse de los tejidos de los conos de ovulación, lo que cuestiona la hipótesis actual de que la polinización de Z. integrifolia se produce por engaño.

  PublisherOA PDFDOI

• A phylogeny of the evening primrose family (Onagraceae) using a target enrichment approach with 303 nuclear loci

  BMC Ecology and Evolution · 2023-11-17 · 11 citations

  articleOpen access

  BACKGROUND: The evening primrose family (Onagraceae) includes 664 species (803 taxa) with a center of diversity in the Americas, especially western North America. Ongoing research in Onagraceae includes exploring striking variation in floral morphology, scent composition, and breeding system, as well as the role of these traits in driving diversity among plants and their interacting pollinators and herbivores. However, these efforts are limited by the lack of a comprehensive, well-resolved phylogeny. Previous phylogenetic studies based on a few loci strongly support the monophyly of the family and the sister relationship of the two largest tribes but fail to resolve several key relationships. RESULTS: We used a target enrichment approach to reconstruct the phylogeny of Onagraceae using 303 highly conserved, low-copy nuclear loci. We present a phylogeny for Onagraceae with 169 individuals representing 152 taxa sampled across the family, including extensive sampling within the largest tribe, Onagreae. Deep splits within the family are strongly supported, whereas relationships among closely related genera and species are characterized by extensive conflict among individual gene trees. CONCLUSIONS: This phylogenetic resource will augment current research projects focused throughout the family in genomics, ecology, coevolutionary dynamics, biogeography, and the evolution of characters driving diversification in the family.

  PublisherOA PDFDOI

Recent grants

• Collaborative Research: Scale- and context-dependence of relative humidity to adult Manduca sexta behavior

  NSF · $278k · 2010–2013

• Collaborative Research: Components of Floral Attraction in a Functionally Specialized but Ecologically Generalized Flower Guild

  NSF · $347k · 2008–2013

• Collaborative Research: Detection, Perception and Utilization of Floral CO2 by Manduca sexta

  NSF · $185k · 2005–2007

• Patterns and Consequences of Fragrance Variation in Oenothera caespitosa

  NSF · $546k · 2003–2008

• Herbarium Improvements for the University of South Carolina

  NSF · $97k · 2004–2007

Frequent coauthors

• Krissa A. Skogen

  Clemson University

  39 shared

• Jeremie B. Fant

  Brooklyn Botanic Garden

  27 shared

• Norman J. Wickett

  Clemson University

  25 shared

• Marcela Moré

  Instituto Multidisciplinario de Biología Vegetal

  24 shared

• Rick Overson

  Arizona State University

  23 shared

• Rachel A. Levin

  Amherst College

  22 shared

• Tania Jogesh

  Brooklyn Botanic Garden

  22 shared

• Joaquín Goyret

  University of Tennessee at Martin

  21 shared

Labs

• Raguso labPI

Education

• PhD, Biological Sciences

  University of Michigan

  1995

• BS, Biology

  Yale College

  1987