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Spatiotemporal Dynamics of Butterflies and Their Floral Resources
(North Dakota State University, 2020) Antonsen, Adrienne Kendra
Butterflies fulfill a unique role among insect pollinators as long-distance flyers. This makes butterflies particularly valuable as vectors of genetic diversity among spatially isolated plant populations. Like many insects, though, butterfly populations have experienced significant declines in recent years. To help inform conservation efforts, and to investigate community and species level dynamics, I studied butterflies and their floral resources as part of a three year pollinator survey across the state of North Dakota. At the community level, I analyzed butterfly-flower interaction networks across space and time. I then examined the specialization of individual species within those networks and their contributions to network structure. I also evaluated spatial and temporal distribution patterns of monarch butterflies, regal fritillaries, and their plant resources. Results revealed dynamic spatiotemporal relationships between butterflies and their plant resources that have important implications for conservation efforts and the study of ecological communities.
Impact of Ragl Aphid Resistant Soybeans on Binodoxys communis (Gahan) (Hymenoptera: Braconidae), a Parasitoid of Soybean Aphid Aphis glycines Matsumura (Hemiptera: Aphididae )
(North Dakota State University, 2011) Ghising, Kiran
After its discovery in North America during the summer of 2000, the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae) became a major pest of the soybean, Glycine max (L.) Merr., in most soybean growing regions of the United States. The use of insect-resistant plant varieties and natural enemies, important components of Integrated Pest Management (IPM), when applied solely have the potential to be effective measures for controlling soybean aphids. However, resistant host plants may influence natural enemies in beneficial or detrimental ways, thereby altering their effectiveness when the two strategies are combined. Therefore, we investigated how a resistant variety impacts fitness of a biological control agent to understand its compatibility for pest management of the soybean aphid. A near isogenic susceptible soybean variety without the Ragl gene and a resistant variety with the Ragl gene were used to determine the effect of the Ragl on the development and fitness of the soybean aphid parasitoid, Binodoxys communis Gahan (Hymenoptera: Braconidae). Before testing for effects of the Ragl gene on the parasitoid, we first validated the expression of the Ragl gene and confirmed that these plants were resistant to soybean aphids by determining the growth rate of soybean aphids on both resistant and susceptible plants. The soybean aphid population and per capita growth rate were significantly higher when reared on susceptible soybean plants compared to resistant plants. In addition, polymerase chain reaction (PCR) was used to verify the genotypes and the presence of the Ragl gene in some of the plants used in the growth rate experiment. Results of the soybean aphid growth rate experiment combined with the results of the PCR helped to validate the expression of the Raglin the resistant plants used in our experiments. To determine the impact of these resistant plants on parasitoids, the total numbers of mummies (parasitized soybean aphids) produced and adult parasitoid emergence were compared for parasitoids that were given aphid hosts from either susceptible or resistant plants. Parasitoid fitness was measured in terms of parasitoid development time, their body length, and their metatibiae length. We found a higher number of mummies in susceptible soybean plants than in the resistant plants as well as a higher emergence rate of adult parasitoids from the mummies reared on susceptible plants. The development time from mummy to adult parasitoid emergence was only one day longer with aphid hosts from resistant plants compared to susceptible plants. Despite some difference in the size of parasitoids from resistant and susceptible plants, very few parasitoids completed development on resistant plants. In summary, our results indicate poorer establishment and reproductive performance of B. communis from soybean aphids on resistant plants compared to soybean aphids on susceptible plants. This suggests that widespread adoption of resistant soybean plants might be detrimental to the overall sustainability of this parasitoid and its ability to help control soybean aphids. We did, however, find that at least some B. communis could successfully develop and emerge on soybean aphids from resistant plants, suggesting that there is at least some possibility that the parasitoid could survive and assist in aphid management even if the Rag 1 resistant plants become commonplace. The parasitoid's relative fitness and reproductive output will likely play important roles in ultimately determining the short- and long-term compatibility of utilizing both B. communis and resistant soybean plants for soybean aphid control.
Investigating the Subspecific Designation of Euschistus servus (Say) (Hemiptera: Heteroptera: Pentatomidae) Using a Combined Landmark-Based Geometric Morphometrics Approach
(North Dakota State University, 2021) Oliveras, Vincent Aron
Euschistus servus is currently subdivided into two subspecies: E. s. servus and E. s. euschistoides. An intergrade population inhabits the central U.S. This study sought to reevaluate the established subspecific designations and determine whether E. servus subspecies and intergrade populations express distinct taxonomically important morphological characteristics throughout the U.S. We quantified landmark-based geometric morphometric data in conjunction with traditional morphometrics from specimens collected along a wide geographic area and used a principal component analysis to determine if there is a significant difference within the subspecies’ morphology, assessing shape between morphogroups failed to produce clusters commensurate to the E. s. servus and E. s. euschistoides forms. Further analysis suggested that there is linear relationship between the taxonomic characters and latitude which may be indicative of clinal variation. This data indicates E. servus should be recognized as polymorphic as opposed to polytypic, disputing the subspecific designation of the E. servus subspecies complex.
Thermal Biology, Overwintering, and a Degree-Day Model for the Adult Emergence of the Red Sunflower Seed Weevil (Coleoptera: Curculionidae)
(North Dakota State University, 2022) Pantzke, Shawna
Red sunflower seed weevil, Smicronyx fulvus LeConte, is a univoltine seed-feeding weevil that is a primary pest of cultivated sunflower, Helianthus annuus, in North America, especially within the upper Great Plains region. This pest spends its final larval stage overwintering in the soil before pupating in the summer and emerging as an adult to feed on sunflower pollen and lay eggs in developing achenes. Larval feeding can damage of up to 83% of seeds on a head. Growers typically manage S. fulvus by using insecticides; however, early planting dates have also been demonstrated to reduce weevil damage. It is important to understand how overwintering conditions impact larval development and develop a model to predict adult emergence. Larvae were found to overwinter in the soil at depths that are not subject to temperatures near their freezing point, and a degree-day model was created for emergence.
Effects of Soybean Aphid Resistance on the Lady Beetle Harmonia axyridis Mediated by the Soybean Aphid Aphis glycines
(North Dakota State University, 2010) Thurn, Anne Christine
Plants can directly and indirectly influence the natural enemies of their herbivores. Such trophic level effects apply to plants in natural and agronomic settings as well as to plants bred for pest resistance and biological control of herbivores. The effects of host plant resistance on herbivore natural enemies are highly variable, depending on the system. Currently, there is great interest in breeding soybean for resistance to the soybean aphid (Aphis glycines Matsumura). However, little is known about the effects of soybean aphid resistance traits on soybean aphid natural enemies. This study looks at the indirect effects of plant resistance to soybean aphid on the lady beetle Harmonia axyridis Pallas (Coleoptera: Coccinellidae ), an important natural enemy of the soybean aphid, using seven soybean varieties that exhibited variable resistance 1o the soybean aphid. Aphids were collected from greenhouse-reared soybean plants and fed to beetles in the laboratory. Harmonia. axyridis larval development time, adult mass, and fecundity over a month were measured. Results indicated moderate and inconsistent indirect effects with highly resistant plant varieties while some moderately-resistant plant varieties reduced adult weight and egg production. My conclusion is that soybean aphid resistance is potentially compatible with H. axyridis biological control, but care must be taken when selecting varieties if there is more than one source of resistance or if plant resistance differentially affects soybean aphids and their natural enemies.
A Phylogenetic Analysis and Revision of the Teleonemia Costa Generic Complex (Hemiptera: Heteroptera: Tingidae)
(North Dakota State University, 2022) Knudson, Alexander
The Teleonemia Costa generic complex includes the genera Alveotingis Osborn & Drake, Eurypharsa Stål, Hesperotingis Parshley, Melanorhopala Stål, Teleonemia, and two undescribed genera. A phylogenetic analysis and revision of all included genera is presented. Representatives of most included species were examined and a phylogenetic analysis, based on morphology, was undertaken to determine the interrelatedness of the included taxa. The results show a polyphyletic Teleonemia, and Melanorhopala. A new genus, Paramelanorhopala is erected to accommodate Hesperotingis illinoiensis Drake, and H. occidentalis Drake. Another new genus will be proposed to accommodate some taxa previously placed in Melanorhopala and Teleonemia. The subgenus Amaurosterphus Stål is resurrected from synonymy and itsmorphological concept is greatly expanded to include taxa originally attributed to Americia Stål. Two new subgenera, Teleonemia (Tapinonemia) and Teleonemia (Trichodonemia) , are erected to accommodate the internal phylogenetic structure of Teleonemia. Teleonemia chilensis (Reed) is resurrected from synonymy from Lepptostyla carmelana Berg. Eurypharsa circumdata (Blanchard, 1842) [new combination, reinstated status], which was placed as a synonym of Tingis nobilis Guérin-Méneville 1944, has priority. Hesperotingis antennata borealis Parshley, is resynonymized with H. antennata Parshley. Hesperotingis duryi confusa Drake is resynonymized and Melanorhopala balli Drake is now synonymized under Hesperotingis duryi (Osborn & Drake). Hesperotingis mississippiensis Drake is synonymized with Hesperotingis floridana Drake. Teleonemia artiflava Monte, T. bierigi Monte, T. bondari Monte, T. crassispinosa Monte, T. jubata Drake & Hambleton, and T. ruthae Monte are all synonymized under Teleonemia forticornis Champion. Teleonemia granulosa Monte is synonymized under T. argentinensis Drake & Poor. Teleonemia huachucae Drake is synonymized under Teleonemia nigrina Champion. Teleonemia novicia Drake is synonymized under Teleonemia vidua Van Duzee. Teleonemia sandersi Drake & Hambleton is resynonymized under Teleonemia inops Drake & Hambleton. Teleonemia schildi Drake is synonymized under Teleonemia rugosa Champion. Teleonemia scrupulosa haytiensis Drake is resynonymized under T. scrupulosa Stål. Teleonemia syssita Drake & Cobben is synonymized under Teleonemia sidae (Fabricius). Teleonemia teretis Drake is synonymized under Teleonemia multimaculata Monte. Two new species of Alveotingis, one new species of Hesperotingis, one new species of Melanorhopala, and thirty nine new species of Teleonemia are described herin.
Exploring Effects of Weed Management in Agroecosystems: Arthropods, Soil Properties and Soybean Production
(North Dakota State University, 2014) Hansen, Ashton Anne
Soil-dwelling arthropods contribute to agroecosystems, but it’s unclear how specific taxa respond to weed management practices. Objectives were to explore 1) response of Collembola to weed management in a glyphosate-tolerant soybean system and 2) impacts of weed management and soil arthropod reduction (via insecticide) on soil and plant parameters. Weed management had variable effects on Collembola, whereas location had a consistent effect on diversity and density. Increased weed pressure decreased soil nitrate and reduced soybean yield. Reduction of soil arthropods didn’t impact soil nitrate or yield, but increased the number of soybean root nodules. This could be due to decreased root herbivores, or overcompensation of the plant. Previous research emphasized effects of plant communities on soil arthropods, but our study suggests soil properties strongly influence arthropod communities. Although this study does not show obvious benefits of soil arthropods, long term insecticide application may be detrimental to crop production.
IfSAR DTM-derived Predictive Flood Models: A Cost-effective Approach to Target Site- Specific Mosquito (Diptera: Culicidae) Control Efforts
(North Dakota State University, 2016) Stenehjem, Jacquelin J.
The study area is the 400 km2 floodplain and wetlands of the upper Missouri River, located in the northwestern corner of North Dakota, near the community of Williston. Regional climate is semiarid, yet the Williston vector control agency battles large populations of Culicidae nearly every spring and summer. Best mosquito management practices (BMPs) are integrated, relying on a combination of thorough, routine, ground-based sampling and surveillance methods to provide important information on which control strategies and evaluations of effective are based. However, the mosquito breeding habitat near Williston is extensive and contains difficult terrain, which makes standard ground-based sampling and surveillance methods impractical. This study analyzed remotely sensed Interferometric Synthetic Aperture Radar (IfSAR) Digital Terrain Model (DTM) elevation data as a potential alternative for ground-based methods. Remotely sensed IfSAR technology is relative low-cost, has high-spatial resolution, is not limited by inclement weather, and only needs to be collected once if local topography remains stable. IfSAR elevation data provides information needed to model hydrological characteristics such as slope, aspect, water flow direction, and accumulation, important considerations in relation to mosquito control efforts. Predictive flood models, developed in this study from the IfSAR elevation data, make it possible to predict the locations of water accumulation within the floodplain as river elevations fluctuate. A vertical root mean squares error (RMSEz) assessment of the full IfSAR elevation data in all land cover classifications combined was 1.071 m, consistent with the vendor’s stated RMSEz of 1 meter. The vertical accuracy of the full IfSAR data was 2.099 meters at the 95% confidence level and is consistent with the 95th percentile accuracy of 2.211 meters. The frequency distribution of errors was generally normal. This study determined that airborne, high-resolution IfSAR DTM-elevation data can serve as an alternative for ground-based sampling and surveillance methods and provide a needed decision support system (DSS) tool to the local vector control agency. The predictive flood models are a new approach for predicting the locations of accumulated water within the floodplain will decrease vector control response time and improve the targeting of site-specific control efforts, which in turn, will decrease overall costs for these services.
Density and Movement of Soybean Aphid, Aphis Glycines (Hemiptra: Aphididae) in Response to Temperature and Resistant Soybean Plants
(North Dakota State University, 2012) Whalen, Rebecca Ann
Movement is one way herbivores respond to their host plant, yet the movement of relatively immobile insects has received little attention. We studied how the movement and density of apterous soybean aphids responds to a resistant soybean variety and different temperatures. In Chapter One, we examined aphid movement both within and between soybean plants that varied in their resistance to aphids. Aphids on resistant plants had a wider dispersal, apparently due to greater aphid movement. Consequently, aphids on resistant plants could move to neighboring susceptible plants, thereby increasing their density. In Chapter Two, we measured aphid density and dispersal on resistant and susceptible plants when insects and plants were exposed to two different temperatures. Here, movement behavior was affected by both plant resistance and temperature. Moreover, temperature and plant resistance interacted to influence aphid density. Our results indicate the important role that movement can play in an herbivore's response to plant resistance.
Oviposition Preference and Larval Host Range of the Sugarbeet Root Maggot
(North Dakota State University, 2012) Msangosoko, Kondwani Richmond
The sugarbeet root maggot, Tetanops myopaeformis Röder, is native to North America; however, its main crop host, sugarbeet, Beta vulgaris L., was introduced to the continent from Europe. This study involved an investigation of the attractiveness of cultivated crops and native North American weed species for oviposition by T. myopaeformis and the relative suitability of these potential host plant species for larval development, thus potentially shedding light on the native and current host range of this pest. Females preferred to oviposit near the following plant species: sugarbeet; spinach, Spinacia oleroceae L.; palmer amaranth, Amaranthus palmeri S. Watts.; common lambsquarters, Chenopodium album L.; redroot pigweed, Amaranthus retroflexus L.; and spear saltbush, Atriplex patula L. Larval survival was highest on spinach, followed by sugarbeet, and spear saltbush (all belonging to the family Chenopodiaceae). This suggests that species within this family likely served as native host plants for T. myopaeformis before the introduction of sugarbeet to North America. Lower larval numbers on common lambsquarters, redroot pigweed, and Palmer amaranth suggest that these species are sub-optimal hosts, despite being attractive for oviposition. Additional findings showed a general lack of oviposition preference by T. myopaeformis females for sunflower, Helianthus annuus L., and common ragweed, Ambrosia artemisiifolia L. These results provide further insights into the rapidly successful host preference shift by this insect to sugarbeet.

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