Functional feeding guild classification of aquatic insects is partly based on mouthpart morphology, but the link between mouthpart morphology and ecological feeding roles is often missed by students in the classroom. We implemented a Jigsaw activity in a freshwater biology course to help students connect morphology and ecology. Paired students dissected two common (to the whole class) and one unique aquatic insect’s mouthparts and predicted their ecological feeding roles. Students then divided into new groups and taught peers about their unique insect. A pre- and post-activity survey measured students’ ability to relate morphology and feeding roles. Open-ended questions graded via a rubric showed students scored significantly higher and provided more answers discussing feeding roles. Likert-type questions probing students’ perceptions of mouthpart importance resulted in marginally higher importance ratings of mouthparts for identification but no differences for insect feeding. On an end-of-the-semester assessment, students generally rated the activity as helpful. Some reported the activity to be difficult due to small insect size. The activity enhanced students’ understanding of the link between mouthparts and feeding roles but may have decreased their engagement due to perceived difficulty. Further modification alleviating difficulty may improve student perceptions while retaining knowledge gains.

Plant traits, used by the invasive insect herbivores to find and select suitable hosts, can play an important role in insect host range expansion. With regard to invasive Lycorma delicatula, it is not well explored, however, how the plant origin affects insect host selection, and whether native and introduced host plants differ in their morphology, lifespan, as well as environmental requirements for growth. We addressed this issue in our study through the comprehensive assessment of 25 relevant plant traits (a total of 27,601 records retrieved from the TRY database), as well as the origin and phylogenetic relationships of 37 host plants of L. delicatula in the U.S. Our results showed that only leaf area, leaf chlorophyll content, and canopy size were significantly greater in the introduced hosts than that in native plants. We did not detect a significant effect of the plant origin on other characteristics. Additionally, no significant differences between native and introduced hosts of L. delicatula in genetic distances from introduced Ailanthus altissima (the most preferred host) were detected. These results, for the first time, suggest strong evidence for ecological fitting which might drive the host plant selection of L. delicatula and its rapid spread in the U.S.

Prevailing agricultural systems dominated by annual crop monocultures, and the landscapes that contain them, lack resilience and multifunctionality. They are vulnerable to extreme weather events, contribute to degradation of soil, water, and air quality, reduce biodiversity, and negatively impact human health, social engagement, and equity. To achieve greater resilience, stability, and multiple ecosystem services therein, and to improve socioeconomic outcomes, we propose a practical framework to gain multifunctionality at multiple scales. This framework includes forages within agroecosystems that have the essential structural features of diversity, perenniality, and circularity. These three structural features are associated with increased resilience, stability, and provision of several ecosystem services, which in turn improve human health and socioeconomic outcomes. This framework improves understanding of, and access to, tools and materials for promoting the adoption of diverse circular agroecosystems with perennial forages. Application of this framework can result in land transformations that solve sustainability challenges in agriculture if policy, economic, and social barriers can be overcome by a transdisciplinary process of equitable knowledge production.

Identification of host plants of the invasive spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), has been the focus of many studies. While the adults and late nymphs are relatively easy to observe on plants and to use for molecular gut-content analysis, studying the early instars is more challenging. This study is the continuation of our ongoing efforts to determine the host range for each developmental stage of L. delicatula. In the present study, we focused exclusively on the first nymphal instars, and we used a novel approach, utilizing "bulk" DNA extracts for DNA metabarcoding of nymphal gut contents, to identify all the detectable plants that the nymphs had ingested prior to being collected. We were able to obtain high-quality amplicons (up to 406 bp) of a portion of the rbcL gene and detect 27 unique ingested plant species belonging to 17 families. Both native and introduced plants with the prevalence of trees and grasses were present among the ingested plants. We also identified 13 novel host plants that have not been previously reported for L. delicatula on the U.S. territory. The results from our study have important applications for developing effective programs on early monitoring of invasive L. delicatula.

Introduced grasses can aggressively expand their range and invade native habitats, including protected areas. Miscanthus sinensis is an introduced ornamental grass with 100+ cultivars of various invasive potential. Previous studies have demonstrated that the invasive potential of M. sinensis cultivars may be linked to seed viability, and some of the physiological traits, such as growth rate. Little is known, however, about whether these traits are associated with response of M. sinensis to insect herbivory, and whether plant tolerance and resistance to herbivory vary among its cultivars; which, in turn, can contribute to the invasive potential of some of M. sinensis cultivars. To address this issue, in our study we explored the response of five cultivars of M. sinensis to herbivory by Melanoplus grasshoppers. We demonstrated that plant responses varied among the cultivars during a season; all the cultivars, but "Zebrinus", demonstrated a significant increase in plant tolerance by the end of the growing season regardless of the amount of sustained leaf damage. Different patterns in plant responses from "solid green" and "striped/spotted" varieties were recorded, with the lowest plant resistance detected for "Autumn Anthem" in the cage experiment. Our results have important applications for monitoring low-risk invaders in protected areas, as well as for biotic resistance of native communities to invasive grasses.

Identification of ingested plant species using polymerase chain reaction (PCR)-based methods is an increasingly useful yet challenging approach to accurately determine the diet composition of insect herbivores and thus their trophic interactions. A typical process of detection of DNA of ingested plants involves the choice of a DNA extraction method, a genomic target region, and/or the best approach for an accurate plant species identification. The wide range of available techniques makes the choice of the most appropriate method for an accurately and timely identification of ingested plants from insect guts difficult. In our study, we reviewed the commonly used PCR-based approaches in studies published from 1977 to 2019, to provide researchers with the information on the tools which have been shown to be effective for obtaining and identifying ingested plants. Our results showed that among five insect orders used in the retrieved studies Coleoptera and Hemiptera were prevalent (33 and 28% of all the records, respectively). In 79% of the studies a DNA barcoding approach was employed. In a substantial number of studies Qiagen DNA extraction kits and CTAB protocol were used (43 and 23%, respectively). Of all records, 65% used a single locus as a targeted plant DNA fragment; trnL, rbcL, and ITS regions were the most frequently used loci. Sequencing was the dominant type of among DNA verification approaches (70% of all records). This review provides important information on the availability of successfully used PCR-based approaches to identify ingested plant DNA in insect guts, and suggests potential directions for future studies on plant–insect trophic interactions.

Identification of ingested plant species using polymerase chain reaction (PCR)-based methods is an increasingly useful yet challenging approach to accurately determine the diet composition of insect herbivores and thus their trophic interactions. A typical process of detection of DNA of ingested plants involves the choice of a DNA extraction method, a genomic target region, and/or the best approach for an accurate plant species identification. The wide range of available techniques makes the choice of the most appropriate method for an accurately and timely identification of ingested plants from insect guts difficult. In our study, we reviewed the commonly used PCR-based approaches in studies published from 1977 to 2019, to provide researchers with the information on the tools which have been shown to be effective for obtaining and identifying ingested plants. Our results showed that among five insect orders used in the retrieved studies Coleoptera and Hemiptera were prevalent (33 and 28% of all the records, respectively). In 79% of the studies a DNA barcoding approach was employed. In a substantial number of studies Qiagen DNA extraction kits and CTAB protocol were used (43 and 23%, respectively). Of all records, 65% used a single locus as a targeted plant DNA fragment; trnL, rbcL, and ITS regions were the most frequently used loci. Sequencing was the dominant type of among DNA verification approaches (70% of all records). This review provides important information on the availability of successfully used PCR-based approaches to identify ingested plant DNA in insect guts, and suggests potential directions for future studies on plant-insect trophic interactions.

Purpose Beneficial soil microbes, such as rhizobia, engage in facultative symbioses in the roots of leguminous host plants to exchange nitrogen for products of photosynthesis, and these symbioses can be altered by biotic and abiotic factors. Here, we investigated how soil nitrate supply and aboveground insect herbivory interact to influence biological nitrogen fixation in Medicago sativa (alfalfa or lucerne). Methods Using field and greenhouse experiments, we quantified above- and belowground allocation of rhizobially fixed nitrogen using isotopic nitrogen ratios in plants with different combinations of herbivory and nitrate supplementation. We caged Empoasca fabae (potato leafhopper) on fixing and non-fixing cultivars of M. sativa and supplemented soils with varied nitrate concentrations. Results We detected strong changes in legume above- and belowground allocation of fixed nitrogen in response to both herbivory and nitrate supply. Moderate nitrate soils, irrespective of herbivory, induced little to no fixed nitrogen allocation across both field and greenhouse experiments. In the field only, non-supplemented soil increased aboveground allocation of fixed nitrogen following herbivore damage but resulted in no changes belowground. In contrast, non-supplemented and high nitrate soils in the greenhouse increased above- and belowground fixed nitrogen allocation relative to moderate nitrate soils. Conclusion Our results demonstrate herbivory drives distinct plant allocation strategies across soil nitrate levels, advancing our understanding of how rhizobia influence legumes both above- and belowground. Herbivory-induced changes in rhizobia-legume symbioses are likely widespread across both agricultural and natural ecosystems.

Black flies are nuisance pests as adults, yet they are best managed in the larval stage in flowing waters. As a result, more effort is put into understanding the distribution of the immature life stages than the blood-seeking females that form nuisance. The seemingly localized nature of Simulium jenningsi Malloch (Diptera: Simuliidae) pest problems in western Maryland offered a study system to investigate the spatial and environmental correlates to their severity. Collections of adult black flies were taken at 260 sites within a 2,000 km 2 region centered on Washington County, Maryland, during June, July, and August of 2 yr. Average S. jenningsi counts were greater in the June of both years compared to July and August. Although S. jenningsi was found at the majority of sampling sites, higher fly counts were significantly clustered in the southern portion of the county where the majority of resident complaints originated. A generalized linear mixed-model (GLMM) approach was used to determine the correlates to S. jenningsi abundance.The highest performing model showed a negative relationship of S. jenningsi counts with the amount of surrounding impervious surface, distance to the riffles along the confluence of the Shenandoah and Potomac Rivers, distance to the closest body of flowing water, and light intensity, as well as a positive relationship with elevation and air temperature. The results suggest S. jenningsi females are not readily found in urban environments in this study region, and the most relevant monitoring locations for S. jenningsi may be outside of human population centers.

Knowledge of the persistence of Cry proteins in transgenic corn residue after harvest is necessary to assess the ecological risk to nontarget organisms. The amount of protein remaining in crop residue declines over time by a combination of microbial decomposition and leaching, both influenced by temperature, precipitation, and the amount of residue-soil contact. Here, we investigated how long biologically active Cry proteins persist in SmartStax corn residue expressing Cry1A.105, Cry1F, Cry2Ab2, Cry3Bb1, and Cry34/35Ab1, when subjected to four post-harvest practices (chisel plow tillage, flail mowing, cover crop planting, and undisturbed residue). Protein activity in residue samples collected up to 25 weeks after harvest was measured by Ostrinia nubilalis feeding bioassays and cross validated with detection frequencies determined by ELISA. All corn residue remained above ground in the flail-mowed and undisturbed treatments, while the cover crop and chisel plow treatments left 88.3 and 39.6% of the residue remaining above ground, respectively. Cry proteins retained biological activity for as long as 24 weeks after harvest when residue was left above ground with less soil contact, typical of no-till corn systems. ELISA detections were positively correlated with results of the feeding bioassays, which revealed the presence of active proteins beyond the point of ELISA detection.

Forages provide favorable habitat and food sources for a wide array of insect species. Integrated pest management (IPM) involves all components of decision making and planning of the overall forage crop production system. Insect management needs to be viewed as an integral component within the overall framework of crop management decision making. The goal of IPM is to stabilize pest populations below an acceptable damage level using techniques that minimize health and environmental hazards while optimizing economic benefits for producers and consumers. This chapter outlines important principles and practices of insect management in forage crops. Pests will continue to evolve in response to pest management practices, including pesticide resistance, breakdown of host plant resistance, and cultural practices that disrupt habitat or food sources. Thus, new management techniques will be needed to maintain current levels of insect pest management.

Temperate headwater streams traditionally have been considered heterotrophic and brown food web dominated with little primary production. Recent work, however, suggests algae on leaves in these streams may play a greater role than previously thought through interactions with microbial decomposers like fungi. Algae also may be important for macroinvertebrates colonizing leaves in streams. Algae are a more nutritious food resource for shredders than fungi and bacteria and provide a food resource for non-shredder macroinvertebrates. In a field experiment, we manipulated light in three low-nutrient and three high-nutrient streams using leaf bags filled with red maple leaves in winter and spring. After four weeks we measured algal and fungal biomass, leaf stoichiometry, and macroinvertebrate abundance and biomass associated with the leaf bags. We also identified the macroinvertebrate community and examined differences in functional feeding guilds and taxa under ambient- and shaded-light treatments and low- and high-nutrient concentrations in relation to measured leaf characteristics. Algal biomass on leaves was greatest in high-nutrient streams and ambient-light treatments in both seasons. Fungal biomass on leaves was greatest in high-nutrient streams and showed a moderate marginally significant positive correlation with algae during the winter. Leaf C:N was negatively correlated to algae in winter and fungi in both seasons, while leaf N:P and C:P were negatively correlated to fungi in winter and algae in spring. Interactions between fungi and algae on leaves and the nutritional importance of each for macroinvertebrates likely change across seasons, potentially impacting macroinvertebrate community composition. Macroinvertebrate diversity did not differ, but biomass was significantly greater in shaded-light treatments during spring. Abundance was highest in the high-nutrient ambient-light conditions in both seasons, corresponding to greatest algal biomass. Functional feeding guild biomass and abundance were related to different leaf characteristics by season and guild. Higher algal biomass was an important factor for colonization of certain macroinvertebrates (e.g., Ephemerella (Ephemeroptera: Ephemerellidae) and Stenonema (Ephemeroptera: Heptageniidae)), while others were more abundant under shaded treatments with lower algal biomass (e.g., Tipula (Diptera: Tipulidae)), indicating taxa-specific responses. Leaf-associated algae may be an important factor mediating macroinvertebrate communities associated with leaves in temperate headwater streams. Our results demonstrate that green and brown food webs intersect within leaf packs, and they cannot be easily disentangled. We therefore should consider both autochthonous and allochthonous resources within headwater streams when examining their communities or developing water management strategies.

Current management practices of nuisance black flies are conducted on an area-wide level and rely on the support of the public to implement programs. In Maryland, a vocal group of residents campaigned their representatives to begin a management program for the black fly Simulium jenningsi Malloch. To determine how residents in Maryland and its surrounding states perceived the severity of black fly nuisance, we deployed surveys online and in-person on the ways their outdoor activities were impacted and the preventive methods used to mitigate nuisance. Online respondents, those with children, and those who had lived in the region for a shorter amount of time were more likely to report black flies as ‘extremely annoying’. Quality-of-life concerns stemming from black fly swarms were primarily related to avoiding outdoor exercise and recreation. The majority of respondents used at least one method of personal protection against black fly annoyance, but satisfaction with any method was low. Methods used by respondents included the removal of standing water and rotting vegetation from their properties, indicating a lack of knowledge about black fly breeding habitats. The results contextualized the needs of residents in future management and topics for outreach efforts to address misconceptions about black fly biology. This study offers an example of the application of social science methodology in understanding the needs of stakeholders in area-wide pest management.

Spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), is an introduced highly invasive insect pest in the US that poses a significant risk to forestry and agriculture. Assessing and predicting plant usage of the lanternfly has been challenging, and little is known regarding the lanternfly nymph association with its host plants. In this study, we focused on: (a) providing a protocol for using molecular markers for food plant identification of L. delicatula; (b) determining whether the ingested plant DNA corresponds with DNA of the plants from which the lanternfly was collected; and, (c) investigating the spectrum of ingested plants. We utilized gut contents of third and fourth instar nymphs that were collected from multiple plants; we isolated ingested plant DNA and identified consumed plants. We demonstrated that (a) up to 534 bp of the rbcL gene from ingested plants can be detected in L. delicatula guts, (b) ingested plants in ~93% of the nymphs did not correspond with the plants from which the nymphs were collected, and (c) both introduced and native plants, as well as woody and non-woody plants, were ingested. This information will aid effective the monitoring and management of the lanternfly, as well as predict the lanternfly host plants with range expansion.

Detection of host plant DNA from sap-feeding insects can be challenging due to potential low concentration of ingested plant DNA. Although a few previous studies have demonstrated the possibility of detecting various fragments of plant DNA from some sap-feeders, there are no protocols available for potato leafhopper, Empoasca fabae (Harris) (Hemiptera: Cicadellidae), a significant agricultural pest. In this study we focused on optimizing a DNA-based method for host plant identification of E. fabae and investigating the longevity of the ingested plant DNA as one of the potential applications of the protocol. We largely utilized and modified our previously developed PCR-based method for detecting host plant DNA from grasshopper and the spotted lanternfly gut contents. We have demonstrated that the trnL (UAA) gene can be successfully utilized for detecting ingested host plant DNA from E. fabae and determining plant DNA longevity. The developed protocol is a relatively quick and low-cost method for detecting plant DNA from E. fabae. It has a number of important applications-from determining host plants and dispersal of E. fabae to developing effective pest management strategies.

Consumptive and nonconsumptive interactions of benthic organisms play important roles in regulating rates of ecosystem services such as nutrient cycling in freshwater ecosystems. Studies of macroinvertebrate communities in drainage ditches have focused on documenting the biodiversity supported by these human-altered environments, but none have explored the ecosystem functions provided by those biological communities in ditches. Bioturbation by burrowing benthic invertebrates in ditch sediments may change rates of biogeochemical processes controlling fluxes of nutrients across the sediment–water interface. We used microcosms to test the effect of four species of burrowing invertebrates (Naididae: Ilyodrilus templetoni, Naididae: Limnodrilus hoffmeisteri, Gammaridae: Crangonyx sp., Chironomidae: Chironomus decorus S.G.) on exchanges of phosphorus between sediment and water from a drainage ditch. These effects were measured across a range of sediment and water characteristics, representing variability within ditches. All species reduced concentrations of P (as molybdenum-reactive phosphorus) in the surface water relative to controls under conditions were sediment porewater was not likely to contain higher concentrations of P than surface water. Decreases in P concentration were linked to changes in the sediment redox potential and water pH. Two species (L. hoffmeisteri and C. decorus) increased P concentrations under conditions where sediment porewater likely had higher concentrations of P than surface water. Increases in P concentrations were likely due to physical changes to the sediment from burrowing, and increased transport of dissolved P from sediment porewater to surface waters. Management of ditches should consider effects of burrowing benthic invertebrates on physical and biogeochemical processes at the sediment–water interface. Habitat manipulation in ditches could lead to unpredicted changes in nutrient dynamics mediated by changes to the burrowing benthic invertebrate community.

Sophonia orientalis (Matsumura), also known as the two-spotted leafhopper, is a widespread exotic pest of many economically important crop plants and ornamental plants in Hawaii. Sophonia orientalis is highly polyphagous and is a major threat to some of the native endemic plants. Despite the successful establishment in Hawaii, interactions of S. orientalis with its host plants remain poorly understood. Previous studies primarily focused on distribution, parasitism, and oviposition of S. orientalis in Hawaii, whereas plant physiological responses to the leafhopper's injury, and, specifically, gas exchange rates in plants, have not yet been described. In this study, we examined a short-term physiological response of a native Hawaiian plant, Hibiscus arnottianus (A. Gray), to injury by S. orientalis. We also explored whether Camellia sinensis (L.) Kuntze, a native host plant of S. orientalis in Asia, exhibits a similar response. We found that H. arnottianus plants demonstrated a rapid (2-d) physiological response to injury accompanied by 40% reduction in rate of photosynthesis and 42% reduction in rate of transpiration, whereas C. sinensis did not exhibit any reduction in gas exchange rates. We did not record any changes in plant chlorophyll levels after plant injury in either species. Our results suggest that H. arnottianus is responding to the leafhopper feeding with a generalized wound response predicted for novel plant-insect herbivore associations. We discuss potential future directions for studies which might focus on host plant responses to S. orientalis in its native versus introduced range.

External structures of insects contribute to the ability of herbivores to select and feed on their host plants. The invasive spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae) is an economically important and polyphagous insect pest in the eastern US. The lanternfly causes substantial damage to many woody plants by sucking phloem sap, reducing photosynthesis, causing weeping wounds, and creating conditions for sooty mold. Lanternfly nymphs switch host plants during their development. However, little is known about relationship between the lanternfly and its plant hosts, and particularly about morphological adaptations of the lanternfly to host plant usage at each developmental stage of the pest. In this study, we focused on assessing changes in morphology of (a) the lanternfly mouthparts (stylets and labium), and (b) the lanternfly tarsal tips (arolia and tarsal claws) at each developmental stage. Our study revealed several developmental patterns among which the presence of the indentations on mandibular stylets in late instars and adults, as well as the exponential growth of the labium and stylet length, and the tarsal claw dispersal during the lanternfly development. Our findings are critical for investigating and predicting the lanternfly host range, and the lanternfly dispersal to new host trees at each developmental stage.

This article summarizes results from a field experiment was across six study sites in Maryland, Pennsylvania, Utah, Virginia, Wisconsin, and Wyoming. The main objective of this study was to evaluate alfalfa and tall fescue mixtures across a wide range of environments to assess mixture productivity, weed suppression, and fertilizer nitrogen replacement value (FNRV) of alfalfa. Earn 1 CEU in Crop Management by reading this article and taking the quiz at www.certifiedcropadviser.org/education/classroom/classes/551 .

Understanding the phenology of a new potential pest is fundamental for the development of a management program. Megacopta cribraria Fabricius (Hemiptera: Plataspidae), kudzu bug, is a pest of soybeans first detected in the United States in 2009 and in Maryland in 2013. We observed the phenology of kudzu bug life stages in Maryland, created a Celsius degree-day (CDD) model for development, and characterized the difference between microhabitat and ambient temperatures of both kudzu, Pueraria montana (Lour.) Merr. (Fabales: Fabaceae) and soybeans, Glycine max (L.) Merrill (Fabales: Fabaceae). In 2014, low population numbers yielded limited resolution from field phenology observations. We observed kudzu bug populations persisting within Maryland; but between 2013 and 2016, populations were low compared to populations in the southeastern United States. Based on the degree-day model, kudzu bug eggs require 80 CDD at a minimum temperature of 14°C to hatch. Nymphs require 545 CDD with a minimum temperature of 16°C for development. The CDD model matches field observations when factoring a biofix date of April 1 and a minimum preoviposition period of 17 d. The model suggests two full generations per year in Maryland. Standard air temperature monitors do not affect model predictions for pest management, as microhabitat temperature differences did not show a clear trend between kudzu and soybeans. Ultimately, producers can predict the timing of kudzu bug life stages with the CDD model for the use of timing management plans in soybean fields.