Addressing emerging issues in entomology: 2023 student debates.

The Entomological Society of America (ESA) Student Debates is an annual student competition at the ESA Annual Meeting organized by Student Debates Subcommittee (SDS) members of the ESA Student Affairs Committee. In conjunction with the 2023 ESA Annual Meeting theme, 'Insects and influence: Advancing entomology's impact on people and policy', the theme of this year's student debate was 'Addressing emerging issues in entomology'. With the aid of ESA membership, the SDS selected the following debate topics: (1) Should disclosure of artificial intelligence large language models in scientific writing always be required? and (2) Is it more important to prioritize honey bee or native pollinator health for long-term food security within North America? Four student teams from across the nation, composed of 3-5 student members and a professional advisor, were assigned a topic and stance. Over the course of 5 months, all team members researched and prepared for their assigned topic before debating live with an opposing team at the 2023 ESA Annual Meeting in National Harbor, Maryland. SDS members additionally prepared and presented introductions for each debate topic to provide unbiased backgrounds to the judges and audience for context in assessing teams' arguments. The result was an engaging discussion between our teams, judges, and audience members on emerging issues facing entomology and its impact on people and policy, such as scientific communication and food security, that brought attention to the complexities involved when debating topics concerning insects and influence.

High-throughput molecular gut content analysis of aphids identifies plants relevant for potato virus Y epidemiology.

Aphids are phloem-feeding insects that reduce crop productivity due to feeding and transmission of plant viruses. When aphids disperse across the landscape to colonize new host plants, they will often probe on a wide variety of nonhost plants before settling on a host suitable for feeding and reproduction. There is limited understanding of the diversity of plants that aphids probe on within a landscape, and characterizing this diversity can help us better understand host use patterns of aphids. Here, we used gut content analysis (GCA) to identify plant genera that were probed by aphid vectors of potato virus Y (PVY). Aphids were trapped weekly near potato fields during the growing seasons of 2020 and 2021 in San Luis Valley in Colorado. High-throughput sequencing of plant barcoding genes, trnF and ITS2, from 200 individual alate (i.e., winged) aphids representing nine vector species of PVY was performed using the PacBio sequencing platform, and sequences were identified to genus using NCBI BLASTn. We found that 34.7% of aphids probed upon presumed PVY host plants and that two of the most frequently detected plant genera, Solanum and Brassica, represent important crops and weeds within the study region. We found that 75% of aphids frequently probed upon PVY nonhosts including many species that are outside of their reported host ranges. Additionally, 19% of aphids probed upon more than one plant species. This study provides the first evidence from high-throughput molecular GCA of aphids and reveals host use patterns that are relevant for PVY epidemiology.

Assessing the adaptive role of cannabidiol (CBD) in Cannabis sativa defense against cannabis aphids.

Cannabis sativa is known for having unique specialized or secondary metabolites, cannabinoids that are derived from an extension of the terpene pathway in the Cannabis lineage and includes more than 100 other similar metabolites. Despite the assumption that cannabinoids evolved as novel herbivory defense adaptations, there is limited research addressing the role of cannabinoids in C. sativa responses to insect herbivores. Here we investigated the role of cannabidiol (CBD), the predominant cannabinoid in hemp, in plant defense against cannabis aphid (Phorodon cannabis), one of the most damaging pests of hemp. We hypothesize that insect feeding may induce changes in cannabinoids as an adaptive strategy for defense. We found that mean fecundity, net reproductive rate (R0) and adult longevity of cannabis aphids was reduced on the high cannabinoid cultivar compared to the low- cannabinoid cultivar in whole plant assays. In contrast, supplementation of CBD in artificial feeding assays increased aphid fecundity from day 1 to day 3. Additionally, aphid feeding did not impact cannabinoid levels in leaf tissues with the exception of Δ9-tetrahydrocannabinol (THC). This suggests that other cannabinoids and/or metabolites such as terpenes are causing the observed decrease in aphid performance in the whole plant assays. In addition to cannabinoids, C. sativa also possesses a range of defense mechanisms via phytohormone signaling pathways that are well described in other plant species. Indeed, cannabis aphid feeding significantly increased levels of the major phytohormones, salicylic acid, jasmonic acid, and abscisic acid, which are known to be involved in plant defense responses against aphid species. These results highlight the interplay between cannabinoid synthesis and phytohormone pathways and necessitate further investigation into this complex interaction.

Virus Infection and Host Plant Suitability Affect Feeding Behaviors of Cannabis Aphid (Hemiptera: Aphididae), a Newly Described Vector of Potato Virus Y.

Aphids are the most prolific vectors of plant viruses resulting in significant yield losses to crops worldwide. Potato virus Y (PVY) is transmitted in a non-persistent manner by 65 species of aphids. With the increasing acreage of hemp (Cannabis sativa L.) (Rosales: Cannabaceae) in the United States, we were interested to know if the cannabis aphid (Phorodon cannabis Passerini) (Hemiptera: Aphididae) is a potential vector of PVY. Here, we conduct transmission assays and utilize the electrical penetration graph (EPG) technique to determine whether cannabis aphids can transmit PVY to hemp (host) and potato (non-host) (Solanum tuberosum L.) (Solanales: Solanaceace). We show for the first time that the cannabis aphid is an efficient vector of PVY to both hemp (96% transmission rate) and potato (91%) using cohorts of aphids. In contrast, individual aphids transmitted the virus more efficiently to hemp (63%) compared to potato (19%). During the initial 15 min of EPG recordings, aphids demonstrated lower number and time spent performing intracellular punctures on potato compared to hemp, which may in part explain low virus transmission to potato using individual aphids. During the entire 8-hour recording, viruliferous aphids spent less time ingesting phloem compared to non-viruliferous aphids on hemp. This reduced host acceptance could potentially cause viruliferous aphids to disperse thereby increasing virus transmission. Overall, our study shows that cannabis aphid is an efficient vector of PVY, and that virus infection and host plant suitability affect feeding behaviors of the cannabis aphid in ways which may increase virus transmission.

Location, location, location: Feeding site affects aphid performance by altering access and quality of nutrients.

Aphid feeding behavior and performance on a given host plant are influenced by the plants' physical and chemical traits, including structural characters such as trichomes and nutritional composition. In this study, we determined the feeding behavior and performance of soybean aphids (Aphis glycines) on the stem, the adaxial (upper), and the abaxial (lower) leaf surfaces during early vegetative growth of soybean plants. Using the electrical penetration graph technique, we found that aphids feeding on the stem took the longest time to begin probing. Once aphids began probing, the sieve elements were more conducive to feeding, as evidenced by less salivation on the stem than either leaf surface. In whole-plant assays, stems harbored higher aphid populations, and aphids had shorter development time on stems than the adaxial and the abaxial leaf surfaces. We compared trichome density and length on the stem, the adaxial, and the abaxial leaf surfaces to investigate whether plant trichomes affected aphid feeding and performance. There were higher density and longer trichomes on stems, which likely resulted in aphids taking a longer time to probe. Still a negative impact on aphid population growth was not observed. Analysis of phloem sap composition revealed that vascular sap-enriched exudates from stems had higher sugars and amino acids than exudates from leaves. In artificial diet feeding assays, the population of aphids reared on a diet supplemented with stem exudates was higher than on a diet supplemented with leaf petiole exudates which is in agreement with results of the whole-plant assays. In summary, our findings suggest that the performance of soybean aphids on a specific plant location is primarily driven by accessibility and the quality of phloem composition rather than structural traits.