About

Clyde Sorenson is a professor in the Department of Entomology and Plant Pathology at North Carolina State University. His research program focuses on the biology and management of insects of agricultural significance in North Carolina and the southeastern United States, with particular emphasis on those affecting tobacco. Over the last seven years, he has concentrated on the interactions between imidacloprid, an insecticide integral to tobacco production, and the natural enemies of caterpillar pests such as parasitoid wasps and hemipteran predators that attack the tobacco hornworm complex and tobacco budworm, noting that imidacloprid has little or no effect on these caterpillar species. Sorenson has also collaborated on applied tobacco pest management issues, including reassessments of economic thresholds and insecticide efficacy. Additionally, he has developed a research program on conservation biology questions related to the Sandhills eco-region of North Carolina, studying native bee responses to prescribed fire, impacts of pine straw extraction on soil arthropods and plants, and the reproductive ecology of federally endangered plants in the Sandhills. His work extends to collaborations on the reproductive ecology of the Venus flytrap and assessments of the impacts of woody biomass removal on arthropods and birds. Although he has no formal extension appointment, he supports the department’s extension mission through presentations at field days and producer meetings.

Research topics

• Biology
• Ecology
• Zoology
• Advertising
• Engineering
• Business

Selected publications

• Phenology of the elongate hemlock scale (Hemiptera: Diaspididae) on Fraser fir Christmas trees in western North Carolina

  Journal of Economic Entomology · 2026-03-29

  articleOpen access

  Understanding the seasonal phenology of an insect pest in a specific region on a specific host is fundamental to the timing of management actions. The elongate hemlock scale, Fiorinia externa Ferris (Hemiptera: Diaspididae), is an invasive insect from Japan known to infest various conifer hosts in its invasive range in eastern North America. The phenology of the scale has been studied on hemlock (Tsuga spp.) hosts in its native range and portions of its invasive range in the northeastern and mid-Atlantic regions of the United States; similar studies are lacking for the southeastern region. In the Southern Appalachians, this scale poses a significant management and regulatory challenge for Fraser fir (Abies fraseri [Pursh] Poir.,) Christmas tree production. The objective of this study was to examine the seasonal phenology of the scale in the western North Carolina production region. Biweekly samples were collected from Fraser fir at three sites over 2 years and analyzed for abundance of each life stage. We found all life stages present at all locations throughout the year. Large variability in egg abundance was observed across 2 years. There was little variability in the abundance of life stages between sampling locations. Substantially more scale eggs, crawlers, 2nd instar nymphs and adult females were observed on the 2 most recent years' needles as opposed to older needles. These findings can help optimize the timing of management practices to control the elongate hemlock scale more effectively.

  PublisherDOI

• Increasing density from population recovery does not explain elevated partial brood loss in a threatened cooperative breeder

  Ornithological applications · 2026-01-30

  articleOpen access

  Abstract Partial brood loss in Dryobates borealis (Red-cockaded Woodpecker), a federally threatened cooperative breeder in the USA, was not associated with increases in population density. Across three populations—Sandhills, North Carolina; Marine Corps Base Camp Lejeune, North Carolina; and Eglin Air Force Base, Florida—we documented no support for density-dependent effects on either early or late partial brood loss. Using long-term nest monitoring data, we evaluated multiple metrics of group size and group density in relation to brood loss at early (egg-to-nestling up to 6–10 days when banded) and late (banding-to-fledgling up to 38–40 days) stages. Reproductive outcomes did not vary with density within populations, indicating that the recent rise in partial brood loss, particularly late in the nestling period, was not driven by increasing density. While both density and partial brood loss have increased over time, these trends appear to be decoupled, highlighting the need to investigate other potential drivers of partial brood loss. Cooperative breeding can buffer reproductive output from density-related pressures through shared parental care, but as densities increase due to conservation-driven population recovery, cooperative breeders may face new or shifting constraints. Variation in reproductive outcomes may be more closely tied to site-specific factors or density-independent pressures such as weather, predation, or habitat quality. As D. borealis populations continue to grow under ongoing recovery efforts, understanding the mechanisms behind partial brood loss remains critical for refining conservation strategies. Our results add to growing evidence that density-dependent effects on reproduction are not universal; increasing density, though a conservation success, does not necessarily lead to reduced productivity or increased brood loss.

  PublisherDOI

• Evaluating the post-harvest survival and emergence of elongate hemlock scale from Fraser fir Christmas trees

  Journal of Economic Entomology · 2025-07-01 · 1 citations

  articleOpen access

  The elongate hemlock scale (Fiorinia externa Ferris; Hemiptera: Diaspididae) is an invasive insect that originated in Japan and was first detected in North America in Queens NY in 1908. It has since become a significant post-harvest pest of Fraser fir (Abies fraseri [Pursh] Poir.), posing regulatory problems for the North Carolina Christmas tree industry which produces trees that are sold and moved across the country. Observations by specialists suggest that crawlers, one of two mobile stages of the insect, can emerge from eggs on host material for an extended period, potentially spreading this scale to new areas. However, research into crawler emergence under variable conditions, as well as the duration harvested Fraser fir can sustain live egg-producing adult female elongate hemlock scale (and thus prolong crawler emergence) is lacking. Therefore, we evaluated these insects' post-harvest activity on cut Fraser fir. In our first study, we evaluated weekly crawler emergence from Fraser fir trees and branches between two post-harvest treatments (baled and unbaled) under constant conditions for 7 wk. The second experiment aimed to simulate a Christmas tree's post-harvest lifecycle, over 13 wk, from lot (outdoor) to home (indoor) to discarding (outdoor). Our results show that crawlers continue to emerge from post-harvest Fraser fir for up to 40 and 90 d in our seven- and 13-wk studies, respectively. Moreover, we found live females with eggs present for up to 50 d post-harvest. These findings highlight the potential risk of introducing this scale to new areas via Fraser fir Christmas tree shipments.

  PublisherOA PDFDOI

• Too cold to handle: Climatic constraints on arboreal ants in temperate forests

  Journal of Animal Ecology · 2025-05-08 · 6 citations

  articleOpen access

  Abstract The macroscale at which we measure, model and predict climate change does not align with the microscale at which small ectotherms experience climate. To understand climate's influence on biodiversity and potential ecological effects of climate change, more work is needed to understand how ectotherm physiology relates to microclimatic temperatures. Tree canopies are an example of a habitat that produces extreme microclimates, and arthropods in tropical forest canopies are threatened by extreme heat and warming. The situation in temperate canopies, however, is less clear. Conventional wisdom suggests that winter cold limits arboreal arthropod diversity in temperate forests, but because the canopy is less buffered from extreme temperatures, summer heat could also play a role. Heat‐ and cold‐limited communities will respond differently to climate change, so this distinction is critical. Using the frameworks of the thermal adaptation hypothesis and thermal niche asymmetry, we asked whether arboreal ants were physiologically adapted to their extreme environment and whether summer heat or winter cold was more stressful. We tracked internal microclimates of ant nests in the canopy and on the ground over the seasonal cycle in temperate forests in North Carolina, USA. Then, we measured the heat (CT max ) and cold tolerance (CT min ) of worker ants in summer and spring and compared them with ants' experienced microclimates. Nests in the temperate canopy experienced hotter and colder extremes and more closely tracked air temperatures than ant nests on the ground. Arboreal ants partially adhered to the thermal adaptation hypothesis. They were more heat tolerant than ground‐nesting species, but despite experiencing lower temperatures, they were less cold‐tolerant. Ants acclimated their cold tolerance in line with seasonal changes, but heat tolerance was more phylogenetically constrained. Summer heat did not approach ants' heat tolerance in either stratum, but winter and spring lows in the canopy exceeded the cold tolerance of ants nesting there. By comparing microclimatic temperatures and thermal physiology, we suggest that winter cold–and not summer heat–likely limits arthropod diversity in the temperate canopy.

  PublisherOA PDFDOI

• Urbanization strengthens vertical stratification of ant nutrient preferences in a temperate forest ecosystem

  PLoS ONE · 2025-03-28 · 2 citations

  articleOpen accessCorresponding

  Resource and nutrient availability varies spatially and influences animal foraging patterns. Under the compensation hypothesis, animals should preferentially forage for the most limiting nutrient in the environment. Animal nutrient preferences have been well studied in the tropics, where terrestrial and arboreal fauna are clearly differentiated and limited by different nutrients. In temperate forests, vertical stratification of the fauna may be less pronounced and its role in foraging ecology is poorly understood. Here, we examine nutrient preference patterns over a vertical gradient in temperate forests and nearby urban centers in North Carolina, USA. Using a bait-choice experiment and novel bait design, we measured ant community nutrient preferences in the canopy and on the ground of 83 trees across 14 sites and assessed ant diversity and community composition. Ant diversity did not differ across the vertical strata or habitat types, but species turnover altered community composition to create four distinct assemblages. In temperate forests, ants did not prefer a particular nutrient in either stratum, likely due to extensive foraging across strata. In urban habitats, however, ant nutrient preferences matched patterns well known from tropical systems: arboreal animals preferred protein, while terrestrial animals preferred carbohydrates. Rather than stratum-specific nutrient limitations, however, we attribute the differences in urban preference patterns to changes in native species' foraging intensity and the addition of uniquely urban species with specific nutrient preferences. These results underscore the necessity of testing ecological hypotheses across biomes and suggest that urbanization may produce established ecological patterns via novel mechanisms.

  PublisherOA PDFDOI

• As prey and pollinators, insects increase reproduction and allow for outcrossing in the carnivorous plant <i>Dionaea muscipula</i>

  American Journal of Botany · 2024-01-30 · 2 citations

  articleOpen accessSenior author

  PREMISE: Understanding the factors that limit reproductive success is a key component of plant biology. Carnivorous plants rely on insects as both nutrient sources and pollinators, providing a unique system for studying the effects of both resource and pollen limitation on plant reproduction. METHODS: We conducted a field experiment using wild-growing Dionaea muscipula J. Ellis (Droseraceae) in which we manipulated prey and pollen in a factorial design and measured flower production, number of fruits, and number of seeds. Because understanding reproduction requires knowledge of a plant species' reproductive and pollination biology, we also examined the pollination system, per-visit pollinator effectiveness, and pollen-ovule (P/O) ratio of D. muscipula. RESULTS: Plants that received supplemental prey produced more flowers than control plants. They also had a higher overall fitness estimate (number of flowers × fruit set (total fruits/total flowers) × seeds per fruit), although this benefit was significant only when prey supplementation occurred in the previous growing season. Neither pollen supplementation nor the interaction between pollen and prey supplementation significantly affected overall plant fitness. CONCLUSIONS: This study reinforces the reliance of D. muscipula on adequate prey capture for flower, fruit, and seed production and a mobile pollen vector for reproduction, indicating the importance of considering insects as part of an effective conservation management plan for this species.

  PublisherOA PDFDOI

• Reaching new heights: Arboreal ant diversity in a North American temperate forest ecosystem

  Insect Conservation and Diversity · 2024-11-10 · 4 citations

  articleOpen access

  Abstract Most canopy insect research takes place in tropical forests, where communities are highly vertically stratified. However, temperate forest canopies also provide critical resources to many species and are under intense pressure from global change drivers. The relative lack of knowledge regarding temperate canopy insect ecology impedes our forest management and conservation decisions such that we may be losing temperate canopy biodiversity before we know it exists. We directly compared ant diversity and community composition on the ground and in the tree canopy of North American temperate deciduous forests for the first time. We also evaluated two canopy sampling methods—baits and hand collections. We collected 34 ant species from 102 trees across seven sites. Ant diversity was greater on the ground than in the canopy, and species turnover created distinct communities across vertical strata. Only 12% of species were exclusively arboreal, but 47% were collected in both strata, indicating the canopy is an important resource for temperate ants, even if they are not restricted there. Baiting and hand‐collecting recovered similar species richness, but whether baits captured a subset of hand‐collected species or a unique assemblage was site‐dependent. Nevertheless, we suggest that these methods are most effective in conjunction. Hand collection allowed us to document arboreal nests of 10 species, including the invasive needle ant, Brachyponera chinensis , which was previously thought to be strictly terrestrial. Our results emphasise the importance of including the canopy in temperate forest ecology and conservation assessments.

  PublisherOA PDFDOI

• Host species differences in the thermal mismatch of host–parasitoid interactions

  Journal of Experimental Biology · 2023 · 13 citations

  • Biology
  • Ecology
  • Zoology

  Extreme high temperatures associated with climate change can affect species directly, and indirectly through temperature-mediated species interactions. In most host-parasitoid systems, parasitization inevitably kills the host, but differences in heat tolerance between host and parasitoid, and between different hosts, may alter their interactions. Here, we explored the effects of extreme high temperatures on the ecological outcomes - including, in some rare cases, escape from the developmental disruption of parasitism - of the parasitoid wasp, Cotesia congregata, and two co-occurring congeneric larval hosts, Manduca sexta and M. quinquemaculata. Both host species had higher thermal tolerance than C. congregata, resulting in a thermal mismatch characterized by parasitoid (but not host) mortality under extreme high temperatures. Despite parasitoid death at high temperatures, hosts typically remain developmentally disrupted from parasitism. However, high temperatures resulted in a partial developmental recovery from parasitism (reaching the wandering stage at the end of host larval development) in some host individuals, with a significantly higher frequency of this partial developmental recovery in M. quinquemaculata than in M. sexta. Hosts species also differed in their growth and development in the absence of parasitoids, with M. quinquemaculata developing faster and larger at high temperatures relative to M. sexta. Our results demonstrate that co-occurring congeneric species, despite shared environments and phylogenetic histories, can vary in their responses to temperature, parasitism and their interaction, resulting in altered ecological outcomes.

  PublisherDOI

• Ground-Dwelling Invertebrate Abundance Positively Related to Volume of Logging Residues in the Southern Appalachians, USA

  Forests · 2020 · 5 citations

  Senior authorCorresponding
  • Ecology
  • Biology

  Invertebrates, especially those dependent on woody debris for a portion of their life cycle, may be greatly impacted by the amount of downed wood retained following timber harvests. To document relationships between invertebrates and logging residues, we sampled invertebrates with pitfall traps placed near or far from woody debris in 10 recently (2013–2015) harvested sites in western North Carolina with varying levels of woody debris retention. We measured the groundcover and microclimate at each trap and estimated site-level woody debris volume. We modeled predictors (e.g., site-level woody debris volume, percent woody debris cover at the trap site, site type) of captures of spiders (Araneae), harvestmen (Opiliones), centipedes/millipedes (Chilopoda/Diplopoda), ground beetles (Carabidae), rove beetles (Staphylinidae), other beetles, ants (Formicidae), grasshoppers (Acrididae/Tetrigidae), crickets (Gryllidae), and cave crickets (Rhaphidophoridae). In addition, we modeled ant occurrence at a finer taxonomic resolution, including red imported fire ants (Solenopsis invicta Buren) and 13 other genera/species. Forest type, whether hardwood or white pine (Pinus strobus L.) overstory preharvest, was a predictor of invertebrate response for 21 of 24 taxonomic analyses. Invertebrate captures or the occurrence probability of ants increased with increasing site-level woody debris volume for 13 of the 24 taxa examined and increased with increasing coarse woody debris (CWD; diameter ≥ 10 cm) cover at the trap level for seven of 24 taxa examined. Our results indicate that woody debris in harvested sites is important for the conservation of a majority of the taxa we studied, which is likely because of the unique microclimate offered near/under woody debris. Stand-scale factors typically were more important predictors of invertebrate response than trap-level cover of woody debris. We recommend implementing sustainability strategies (e.g., Biomass Harvesting Guidelines) to retain woody debris scattered across harvested sites to aid in the conservation of invertebrates.

  PublisherOA PDFDOI

• Buzz, Sting, Bite: Why We Need Insects

  American Entomologist · 2020 · 3 citations

  1st authorCorresponding
  • Biology
  • Zoology
  • Business
  PublisherOA PDFDOI

Frequent coauthors

• A. S. Stephenson

  North Carolina State University

  15 shared

• George G. Kennedy

  13 shared

• J. R. Bradley

  11 shared

• Hannah Burrack

  10 shared

• Aurora Toennisson

  North Carolina State University

  9 shared

• Scott B. Clewis

  8 shared

• C. E. Ratz

  North Carolina State University

  8 shared

• R. Michael Roe

  North Carolina State University

  7 shared

Labs

• Structural Pest Management Training & Research FacilityPI

Awards & honors

• CS Alumni Assoc. Distinguished Undergrad. Professor