Camila C. Filgueiras

As many pollinator populations around the world decline due to habitat loss, improving management practices for native pollinators becomes a priority. Pollinators are essential to healthy ecosystems and play irreplaceable roles in the global food system. Pollinator hotels can provide a safe, protected space suited for many different species, and can also be used as educational tools. However, these structures also often contain parasites attracted to the nests within, which can multiply without maintenance. Pollinator hotels are usually filled with nesting cavities in a variety of materials including cardboard, reeds, bamboo, and native plant stems. This study sought to determine whether any materials are more or less prone to parasitic infestation and whether introducing emergence boxes for overwintering bees could offer a solution. We first conducted a family-level biodiversity survey to examine the parasite populations in pollinator hotels. Second, we conducted a controlled study of parasite burden in three material types. Third, we investigated emergence boxes as a tool to facilitate cleaning and maintenance of pollinator hotels with the overall goal of reducing parasitic infestation. We found that cardboard tubes had far higher rates of parasitism than other materials across multiple families of parasites. Elimination of cardboard nest tubes, coupled with regular maintenance, may help protect against parasitism. We also found emergence boxes to be a safe and effective way to house overwintering bees while maintenance is performed; in emergence boxes, very few new parasite holes appeared, and bees and wasps rarely constructed new nests. These results provide guidance for researchers and educators constructing pollinator hotels to select nest materials that safeguard pollinators and implement evidence-based maintenance practices that support pollinators across a wide variety of ecosystems.

Soils are among the most biodiverse ecosystems on the planet, home to staggering amounts of small organisms. Many of these organisms are not known to science. This biodiversity 'dark matter' remains largely unexplored because identifying small soil organisms requires either specialized taxonomic expertise or expensive molecular methods, creating a throughput bottleneck that restricts ecosystem-scale monitoring. To explore this dark matter, we developed a high-throughput digital phenotyping approach using multispectral flow cytometry to create digital 'fingerprints' of soil organisms. Analyzing 2318 organisms spanning nematodes, collembola, mites, and tardigrades, we show that these digital fingerprints distinguish taxonomic groups with high accuracy and capture phylogenetic signal that explains 91% of variance in DNA barcode relationships. Machine learning alignment enables us to assess genetic similarity based solely on digital fingerprints, allowing prediction of relationships without sequencing. Smart sampling strategies guided by these projections achieve 6-fold improvements in species discovery efficiency compared to traditional approaches, with advantages that compound as sampling increases. Our smart sampling approach has applications across domains and provides a scalable pathway for rapid biodiversity assessment with immediate applications in agriculture, conservation, and ecosystem monitoring.

The American chestnut (Castanea dentata (Marsh.) Borkh.) was a foundation species whose loss reshaped eastern North American forests. Ongoing breeding with blight-resistant Chinese chestnut (Castanea mollissima Blume) represents the leading strategy for its restoration. However, breeding programs have focused almost exclusively on pathogen resistance, leaving susceptibility to native seed predators unexamined—a critical gap, because nut production underpins the ecological function that restoration seeks to recover. Here, we investigate how hybridization level affects infestation by the lesser chestnut weevil (Curculio sayi (Gyllenhal, 1836)), monitoring 25 genetic lines across four genetic categories (Chinese, F₁, backcross, and American) for larval emergence, weight loss, damage, and emergence timing over eight weeks. Hybridization dramatically altered susceptibility: F₁ hybrids were the most susceptible category. No larval emergence was observed from American chestnuts, and backcross hybrids remained substantially susceptible despite three–four generations of backcrossing. These results expose a fundamental trade-off for restoration: blight resistance derives from the Chinese genome, whereas weevil resistance appears to be associated with the American genome. Backcross lines bred for blight resistance retain weevil susceptibility, and F₁ hybrids risk functioning as pest sinks that amplify local weevil populations. Incorporating weevil resistance screening into breeding programs could help us to ensure that restored chestnuts can fulfill their historical role as mast-producing foundation trees.

Entomopathogenic nematodes (EPNs) are valuable biological control agents and research models in agriculture and ecology. Traditional extraction and rearing methods for EPNs, such as the Baermann funnel and White trap, work well but have limitations in efficiency and practicality. The NEMA Device, constructed from PVC components, was designed to address these limitations by combining extraction and rearing into a single tool with improved portability, scalability, and ease of use. The efficiency of the NEMA Device was evaluated by comparing it to the conventional Baermann funnel extraction method and the White trap method for nematode multiplication. Validation of the instrument was performed using two nematode species, Steinernema khuongi and Heterorhabditis bacteriophora, which vary in size and can be used for pest control. Our results demonstrated that the NEMA Device achieved higher recovery rates of both S. khuongi and H. bacteriophora compared to the Baermann method. Additionally, the production rate of nematodes using the NEMA Device was comparable to that of the White trap method, with no significant difference observed between the two methods. The NEMA Device offers a standardized, cost-effective methodology for the extraction and multiplication of EPNs, enhancing the accessibility and efficiency of studying these agriculturally important nematodes and potentially improving biological control outcomes.

The cross-hybridization of American chestnut (Castanea dentata (Marsh.) Borkh.) with Chinese chestnut (Castanea mollissima Bl.) is a promising strategy for restoring a blight-resistant strain of this keystone species to the Appalachian mountains. To assess the ecological impacts of hybridization on invertebrate communities, we conducted a study across chestnut plots with varying degrees of hybridization (75%, 94%, or 100% American chestnut). Our findings indicate American chestnut hybridization impacted invertebrate communities above- and belowground. Aboveground insect community composition, insect herbivory, gall infestation, and belowground invertebrate diversity were all altered. While some of these differences could be explained by different growth habits or environmental differences, stark differences in Asian chestnut gall wasp infestation (Dryocosmus kuriphilus Yasumatsu.) suggest a genetic component. These results suggest that chestnut hybridization, and particularly expanded restoration efforts using chestnut hybrids, could impact invertebrate communities above- and belowground in addition to pest dynamics. Understanding these effects is crucial for successful chestnut restoration and ecosystem management.

BACKGROUND: A variety of environmental factors can disrupt biotic interactions between plants, insects and soil microorganisms with consequences for agricultural management and production. Many of these belowground interactions are mediated by volatile organic compounds (VOCs) which can be used for communication under appropriate environmental conditions. Behavioral responses to these compounds may likewise be dependent on varying soil conditions which are influenced by a changing climate. To determine how changing environmental conditions may affect VOC‐mediated biotic interactions, we used a belowground system where entomopathogenic nematodes (EPNs) – tiny roundworm parasitoids of soil‐borne insects – respond to VOCs by moving through the soil pore matrix. Specifically, we used two genera of EPNs – Heterorhabditis and Steinernema – that are known to respond to four specific terpenes – α‐pinene, linalool, d‐limonene and pregeijerene – released by the roots of plants in the presence of herbivores. We assessed the response of these nematodes to these terpenes under three moisture regimes to determine whether drier conditions or inundated conditions may influence the response behavior of these nematodes.RESULTS: Our results illustrate that the recovery rate of EPNs is positively associated with soil moisture concentration. As soil moisture concentration increases from 6% to 18%, substantially more nematodes are recovered from bioassays. In addition, we find that soil moisture influences EPN preference for VOCs, as illustrated in the variable response rates. Certain compounds shifted from acting as a repellent to acting as an attractant and vice versa depending on the soil moisture concentration.CONCLUSION: On a broad scale, we demonstrate that soil moisture has a significant effect on EPN host‐seeking behavior. EPN efficacy as biological control agents could be affected by climate change projections that predict varying soil moisture concentrations. We recommend that maintaining nematodes as biological control agents is essential for sustainable agriculture development, as they significantly contribute not only to soil health but also to efficient pest management. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Onion maggot (Delia antiqua) is a prominent pest of allium crops in temperate zones worldwide. Management of this pest relies on prophylactic insecticide applications at planting that target the first generation. Because effective options are limited, growers are interested in novel tactics such as deployment of entomopathogenic nematodes. We surveyed muck soils where onions are typically grown to determine if entomopathogenic nematode species were present, and then evaluated the compatibility of entomopathogenic nematode species with the insecticides commonly used to manage D. antiqua. We also evaluated the efficacy of these entomopathogenic nematodes for reducing D. antiqua infestations in the field. No endemic entomopathogenic nematodes were detected in surveys of muck fields in New York. Compatibility assays indicated that, although insecticides such as spinosad and, to some extent, cyromazine did cause mortality of entomopathogenic nematodes, these insecticides did not affect infectivity of the entomopathogenic nematodes. Field trials indicated that applications of entomopathogenic nematodes can reduce the percentage of onion plants killed by D. antiqua from 6% to 30%. Entomopathogenic nematodes reduced D. antiqua damage and increased end of season yield over two field seasons. Applications of entomopathogenic nematodes may be a viable option for reducing D. antiqua populations in conventional and organic systems. Together with other management tactics, like insecticide seed treatments, applications of entomopathogenic nematodes can provide a yield boost and a commercially acceptable level of D. antiqua control.

The lesser chestnut weevil, Curculio sayi (Gyllenhal), can cause irreparable damage to chestnuts through direct consumption and/or introduction of secondary pathogens. With the resurgence of blight resistant American Chestnut plantings both for commercial production and for habitat restoration, C. sayi has become a similarly resurgence pest. Here, we investigated the nature and extent of C. sayi larval damage on individual nuts and collected harvests with an eye toward the quantifying impacts. Next, we explored management options using biological control including entomopathogenic fungi and entomopathogenic nematodes. Nut damage from C. sayi can be extensive with individual nuts hosting several larvae, larvae emerging from nuts several weeks post harvest, and nut weight loss even after C. sayi have emerged from the nut. Applications of entomopathogenic fungi reduced chances of chestnut infestation, while certain strains of entomopathogenic nematodes increased the probability of C. sayi larval mortality. Understanding C. sayi damage and exploring biological control management options could be a useful tool in the effective management of this resurgent pest.

With the introduction in recent years of high-yield blight-resistant chestnut varieties, the commercial chestnut industry in the United States is expanding. Accompanying this expansion is a resurgence in a primary pest of chestnut: C. sayi, the lesser chestnut weevil. This weevil damages the nut crop and infestations can surge from 0 to close to 100% in as little as two years. Understanding the dynamics of this pest has been challenging. Most work was conducted in the 1900s and only recently has this weevil garnered renewed interest. Recent work on C. sayi phenology has been completed in Missouri but conflicted with anecdotal reports from northern growers. From 2019 to 2020, we used a combination of trapping and microcosm studies to understand both C. sayi phenology and the means of monitoring this pest. C. sayi populations were univoltine and peaked in mid-October. Pyramid traps were the most effective at capturing adult C. sayi. C. sayi larvae, pupae, eclosed adults, and emerging adults were recovered from microcosm experiments. These results suggest that C. sayi emerges later in the northern US with the potential for a single generation to emerge over multiple subsequent years. Understanding C. sayi phenology along with the means of monitoring forms the basis for effective management and control in commercial chestnut orchards.