Research Entomologist
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Contact Information USDA-ARS Daniel K. Inouye U.S. Pacific Basin Agricultural Research Center |
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Publications
via ARIS system
Via Google scholar
Education
PhD, Entomology, University of Florida 2017
MA, Experimental Psychology, University of Texas Pan American 2012
BS, Neuroscience, Tulane University, 2007
Academic Positions
2020 – present, Research Entomologist, USDA-ARS, U.S. Pacific Basin Agricultural Research Center, Hilo, Hawaii
2017 - 2020, Postdoctoral Research Associate, Department of Entomology, Cornell AgriTech, Geneva, NY
Research Accomplishments
While I’m broadly interested in the factors affecting successful invasion among agricultural arthropod pests, my overall research and program goal is to combine basic and applied entomological science to develop new, innovative approaches to pest management that are economically feasible, ecologically friendly, and environmentally sustainable.
For the last ten years, I’ve worked collaboratively with growers and researchers across the country to study the behavior, physiology, and pest management practices for two of the most significant invasive arthropods in the world. During my doctorate at the University of Florida, I studied the host preferences and reproduction of the Asian citrus psyllid (Diaphorina citri) in commercial and homeowner citrus. Subsequently, during my postdoctoral research appointment, I focused on the overwintering biology, nutritional/landscape ecology, and integrated pest management of spotted-wing drosophila (Drosophila suzukii) in berry crops of Western NY.
1. First to describe learning and memory in citri
While I’m broadly interested in the factors affecting successful invasion among agricultural arthropod pests, my overall research and program goal 
is to combine basic and applied entomological science to develop new, innovative approaches to pest management that are economically feasible, ecologically friendly, and environmentally sustainable.
For the last ten years, I’ve worked collaboratively with growers and researchers across the country to study the behavior, physiology, and pest management practices for two of the most significant invasive arthropods in the world. During my doctorate at the University of Florida, I studied the host preferences and reproduction of the Asian citrus psyllid (Diaphorina citri) in commercial and homeowner citrus. Subsequently, during my postdoctoral research appointment, I focused on the overwintering biology, nutritional/landscape ecology, and integrated pest management of spotted-wing drosophila (Drosophila suzukii) in berry crops of Western NY.
2. Developed the physiogenesis model of thermal susceptibility in suzukii
Like ACP, Spotted-wing drosophila (SWD) is an invasive fruit pest native to east Asia. However, unlike ACP, SWD is not restricted to tropical and subtropical climates, and rather than an oligophagous feeding style which largely restricts ACPs host choices to citrus and closely related Rutacae, SWD is a truly polyphagous pest that feeds saprotrophically on many organic substrates. SWD were introduced into the U.S. along the West coast during 2008 and within four years spread to the east coast, as far north as Canada and as far south as Mexico. During that time, there have been many questions regarding the overwintering ability of this species and its potential northern range expansion. For that reason, I spent a considerable portion of my postdoctoral appointment focused on the thermal biology of this species, specifically as it relates to the Great Lakes region of the American Midwest and western New York State. 
My early research demonstrated how gradual cooling lowers the lethal limits of thermal survival presumably via the induction of cold tolerance biochemical pathways and allows SWD to inhabit climates that are otherwise considered beyond the boundaries of survival for this species (Stockton et al. 2018). Further, I identified methods of acclimation in juvenile and adults, describing the timing, duration, and extent of cold exposure required to achieve sufficient cold tolerance to survival extended periods below freezing (Stockton et al. 2020a). Through multistate a multistate collaboration with researchers in Oregon, Michigan, Wisconsin, Maine, Georgia, North Carolina, and Florida, I also described regional variation in phenotype expression consistent with regional variation in climate (Stockton et al. 2020a) and field tested survival parameters (Stockton et al. 2019a) based on naturally occurring biotic (biological and phenotypic factors and access to diet) and abiotic conditions (temperature, refuge). Using that information, we have been able to construct a complex working model of SWD overwintering survival and includes each of the factors, and we are working to incorporate these nuanced data into various predictive modeling programs aimed at forecasting seasonal pest pressure based on prior winter conditions. Spotted-wing drosophila has also been present in Hawaii since the 1980s but doesn’t serve as a major crop pest, likely because its preferred cultivated host fruit (Rubus ideaus and Vaccinium corymbosum) are not grown on a large scale in tropical climates.
3. Identified offseason resources likely used by overwintering suzukii
Because the thermal biology of SWD suggested that overwintering was likely, even in areas as far north as zone 5, I also focused on the nutritional ecology and habitat selection behaviors of SWD in the New York landscape. Using a combination of lab assays and field collections, we identified novel non-crop hosts including fungal fruiting bodies, including store bought and wild fungi, and animal manure from both avian and bovine sources, which are plentiful in the area (Stockton et al. 2019b).
We found that SWD readily accept these less-preferred resources as oviposition sites, however, this is based on a hierarchical selection system of resource availability. This means, that less-preferred (fungi and manure) resource use goes up as preferred hosts (fruit) become scarce (Stockton & Loeb, in preparation). There are evolutionary implications of such a hierarchical system, and this bet-hedging host selection behavior likely helps maintain niche separation when competition with more aggressive drosophila peaks during the summer. The practical implication of this work is that we may expect SWD to overwinter near source of non-crop nutritional resources, such as near bird roosting sites, near dairy farms, and in wooded areas where fungal growth is maintained year round under leaf litter, on sap flux, and/or in tree bark. Given those implications we have also explored non-crop habitat and refuge use during the offseason. Extensive trapping, laboratory based behavioral assays, and experimental field trials have aimed to address which structural features SWD find attractive and how difference forms of refuge provide abiotic microclimate benefits.
4. Tested new methods of integrated pest management of suzukii in Western NY
In addition to my work on the biology and ecology of invasive pests, which is certainly important for developing downstream management tools, I have also tested and developed methods of SWD management in the field. This has been based on approaches used against other similar pests and understanding how to best implement existing technologies given the unique biology of SWD.
To summarize this area of research, I have worked on three key approaches for management of SWD: 1) insecticidal applications, 2) physical control, and 3) behavioral-based management. 
This has translated as research on improving how we apply pesticides to our berry crops, large-scale and multi-year testing of exclusion netting systems in raspberries and blueberries (Stockton et al. 2020b), and research on how to best deliver semiochemical repellent chemicals via automated puffers in the field to deter oviposition by adult female flies (Stockton et al. 2020c). As a result of these studies we have been able to make recommendations to growers in NY, and other areas of the Northeastern United States, regarding the implementation of more well-rounded integrated pest management programs. The program that is furthest down the line in research, and thus implementation, is the exclusion netting system. We are now recommending to growers for small to mid-sized farms where the costs of the structures is off-set by the reduced costs of chemical management or increased in consumer confidence, which is very important in a state like NY which has a considerable U-Pick industry that is insecticide-intolerant. In the future, we hope that our research on optimized automated puffers and more targeted ground sprays will also develop sufficient to make grower recommendations regarding these practices, but that goal is still a few years away.
Service, Leadership and Participation in Professional Activities:
- 2013 – present | Professional Member of the Entomological Society of America
National, Southeastern (2013-2017), and Eastern Branch Affiliations (2017-2020)
- 2017 – 2019 | Professional member of WERA 1021
Multistate Research Coordinating Committee and Information Exchange Group
Honors, Awards, Achievements and Recognition:
- 2020 - $100,000 USDA – Specialty crops block grant (SCBG) Stockton, D.G., Loeb, G.M. Promoting pollinators in New York berry crops in the era of spotted-wing drosophila. Submitted Feb 9, 2020. Recommended for funding April 25, 2020.
- 2020 - $165,000 - USDA-NIFA AFRI Postdoctoral Research Fellowship Program Code: A7201. Determining the Spatio-Temporal Dynamics of Cultivated and Wild Resource Use by Drosophila suzukii Using Novel qPCR Gut Contents Analysis. Submitted July 18, 2019. Funded May 26, 2020.
- 2019 - 1st place winner of the Entomological Society of America Grant Challenge. Iglesias, L., Stockton, D. G., Harding, R. Evaluating visual preferences of allium leafminer to improve monitoring technology. Award amount $1750 for research use.
- 2013 - Hunt Brother’s Fellowship A competitive 4-year research assistantship award for students studying horticultural sciences at the University of Florida CREC in Lake Alfred, FL.
Selected Publications:
- Stockton, D.G., Diepenbrock, L., Burrack, H., Rendon, D., Walton, V., Leach, H., Isaacs, R., Neilsen, A., Iglesias, L., Liburd, O., Drummond, F., Ballman, E., Guedot, C., Wallingford, A. K., and Loeb, G.M. (2020a). Seasonal polyphenism of Spotted-wing Drosophila is affected by variation in local abiotic conditions within its invaded range, likely influencing survival and regional population dynamics. Ecology and Evolution, 10(14), 7669-7685; https://doi.org/10.1002/ece3.6491.
- Stockton, D.G., Hesler, S., Wallingford, A.K., Leskey, T.C., McDermott, L., Elsensohn, J.E., Riggs, D. I., Riggs, M., Loeb, G.M. (2020b). Factors affecting the implementation of exclusion netting to control Drosophila suzukii on primocane raspberry. Crop Protection, 135; https://doi.org/10.1016/j.cropro.2020.105191
- Stockton, D. G., Wallingford, A.K., Cha, D.H., Loeb, G. M. (2020c). Automated aerosol puffers effectively deliver 1-octen-3-ol, an oviposition antagonist useful against spotted-wing Drosophila. Pest Management Science, https://doi.org/10.1002/ps.6028
- Stockton, D.G., Wallingford, A., Rendon, D., Fanning, P., Green, C. K., Diepenbrock, L., Ballman, E., Walton, V., Isaacs, R., Leach, H., Sial, A. A., Drummond, F., Burrack, H., and Loeb, G.M. (2019a). Interactions between biotic and abiotic factors affect survival in overwintering Drosophila suzukii (Matsumura). Environmental Entomology, nvy192, https://doi.org/10.1093/ee/nvy192.
- Stockton, D. G., Brown, R., Loeb, G. M. (2019b). Not Berry Hungry? Discovering the hidden food sources of a small fruit specialist, Drosophila suzukii. Ecological Entomology, 44(6), 810-822. https://doi.org/10.1111/een.12766.
- Stockton, D.G., Wallingford, A.K., Loeb, G.M. (2018). Phenotypic plasticity and overwintering survival in Drosophila suzukii. Insects, 9(3), 105; https://doi.org/10.3390/insects9030105.
- Stockton, D. G., Pescitelli, L. E., Ebert, T. A., Martini, X., & Stelinski, L. L. (2017a). Induced Preference Improves Offspring Fitness in a Phytopathogen Vector. Environmental Entomology, nvx135, https://doi.org/10.1093/ee/nvx135.
- Stockton, D. G., Pescitelli, L. E., Martini, X., & Stelinski, L. L. (2017b). Female mate preference in an invasive phytopathogen vector: how learning may influence mate choice and fecundity in Diaphorina citri. Entomologia Experimentalis et Applicata, 164(1), 16-26. https://doi.org/10.1111/eea.12590.
- Stockton, D. G., Martini, X., Stelinski, L. L. (2017c). Male psyllids differentially learn in the context of copulation. Insects, 8(1), 16; https://doi:10.3390/insects8010016.
- Stockton, D. G., Martini, X., Patt, J. M., & Stelinski, L. L. (2016). The influence of learning on host plant preference in a significant phytopathogen vector, Diaphorina citri. PLoS One, 11(3), e0149815.
- Patt, J. M., Stockton, D., Meikle, W. G., Sétamou, M., Mafra-Neto, A., & Adamczyk, J. J. (2014). Innate and conditioned responses to chemosensory and visual cues in Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), vector of Huanglongbing pathogens. Insects, 5(4), 921-941.
