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1. Border Interceptions Reveal Variable Bridgehead Use in the Global Dispersal of Insects

   https://doi.org/10.1111/geb.13924  

   Worm, Thom; Saffer, Ariel; Takeuchi, Yu; Walden‐Schreiner, Chelsey; Jones, Chris; Meentemeyer, Ross (December 2024, Global Ecology and Biogeography)

   ABSTRACT AimThe global, human‐mediated dispersal of invasive insects is a major driver of ecosystem change, biodiversity loss, crop damage and other effects. Trade flows and invasive species propagule pressure are correlated, and their relationship is essential for predicting and managing future invasions. Invaders do not disperse exclusively from the species' native range. Instead, the bridgehead effect, where established, non‐native populations act as secondary sources of propagule, is recognised as a major driver of global invasion. The resulting pattern of global spread arises from a mixture of global interactions between invasive species, their vectors and, their invaded ranges, which has yet to be fully characterised. LocationGlobal. Time Period1997–2020. Major Taxa StudiedInsects. MethodsWe analysed 319,283 border interception records of 514 insect species from a broad range of taxa from four national‐level phytosanitary organisations. We classified interceptions as coming from species native range or from bridgehead countries and examined taxonomic autocorrelation of global movement patterns between species. ResultsWhile 65% of interceptions originated from bridgehead countries, highlighting the importance of the bridgehead effect across taxa, patterns among individual species were highly variable and taxonomically correlated. Forty per cent of species originated almost exclusively from their native range, 28% almost exclusively from their non‐native range and 32% from a mix of source locations. These patterns of global dispersal were geographically widespread, temporally consistent, and taxonomically correlated. ConclusionsDispersal exclusively from bridgeheads represents an unrecognised pattern of global insect movement; these patterns emphasise the importance of the bridgehead effect and suggest that bridgeheads provide unique local conditions that allow invaders to proliferate differently than in their native range. We connect these patterns of global dispersal to the conditions during the human driven global dispersal of insects and provide recommendations for modellers and policymakers wishing to control the spread of future invasions. 

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2. Untangling an insect’s virome from its endogenous viral elements

   https://doi.org/10.1186/s12864-023-09737-z  

   Rozo-Lopez, Paula; Brewer, William; Käfer, Simon; Martin, McKayla M.; Parker, Benjamin J. (October 2023, BMC Genomics)

   Abstract BackgroundInsects are an important reservoir of viral biodiversity, but the vast majority of viruses associated with insects have not been discovered. Recent studies have employed high-throughput RNA sequencing, which has led to rapid advances in our understanding of insect viral diversity. However, insect genomes frequently contain transcribed endogenous viral elements (EVEs) with significant homology to exogenous viruses, complicating the use of RNAseq for viral discovery. MethodsIn this study, we used a multi-pronged sequencing approach to study the virome of an important agricultural pest and prolific vector of plant pathogens, the potato aphidMacrosiphum euphorbiae. We first used rRNA-depleted RNAseq to characterize the microbes found in individual insects. We then used PCR screening to measure the frequency of two heritable viruses in a local aphid population. Lastly, we generated a quality draft genome assembly forM. euphorbiaeusing Illumina-corrected Nanopore sequencing to identify transcriptionally active EVEs in the host genome. ResultsWe found reads from two insect-specific viruses (aFlavivirusand anAmbidensovirus) in our RNAseq data, as well as a parasitoid virus (Bracovirus), a plant pathogenic virus (Tombusvirus), and two phages (Acinetobacter and APSE). However, our genome assembly showed that part of the ‘virome’ of this insect can be attributed to EVEs in the host genome. ConclusionOur work shows that EVEs have led to the misidentification of aphid viruses from RNAseq data, and we argue that this is a widespread challenge for the study of viral diversity in insects. 

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3. Wood fibers are a crucial microhabitat for cellulose- and xylan- degrading bacteria in the hindgut of the wood-feeding beetle Odontotaenius disjunctus

   https://doi.org/10.3389/fmicb.2023.1173696  

   Schwarz, Melbert; Beza-Beza, Cristian F.; Mikaelyan, Aram (June 2023, Frontiers in Microbiology)

   IntroductionWood digestion in insects relies on the maintenance of a mosaic of numerous microhabitats, each colonized by distinct microbiomes. Understanding the division of digestive labor between these microhabitats- is central to understanding the physiology and evolution of symbiotic wood digestion. A microhabitat that has emerged to be of direct relevance to the process of lignocellulose digestion is the surface of ingested plant material. Wood particles in the guts of some termites are colonized by a specialized bacterial fiber-digesting microbiome, but whether this represents a widespread strategy among insect lineages that have independently evolved wood-feeding remains an open question. MethodsIn this study, we investigated the bacterial communities specifically associated with wood fibers in the gut of the passalid beetleOdontotaenius disjunctus. We developed a Percoll-based centrifugation method to isolate and enrich the wood particles from the anterior hindgut, allowing us to access the wood fibers and their associated microbiome. We then performed assays of enzyme activity and used short-read and long-read amplicon sequencing of the 16S rRNA gene to identify the composition of the fiber-associated microbiome. ResultsOur assays demonstrated that the anterior hindgut, which houses a majority of the bacterial load, is an important site for lignocellulose digestion. Wood particles enriched from the anterior hindgut contribute to a large proportion of the total enzyme activity. The sequencing revealed thatO. disjunctus, like termites, harbors a distinct fiber-associated microbiome, but notably, its community is enriched in insect-specific groups ofLactococcusandTuricibacter. DiscussionOur study underscores the importance of microhabitats in fostering the complex symbiotic relationships between wood-feeding insects and their microbiomes. The discovery of distinct fiber-digesting symbionts inO. disjunctus, compared to termites, highlights the diverse evolutionary paths insects have taken to adapt to a challenging diet. 

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4. The Undergraduate Engineering Mental Health Help‐Seeking Instrument (U E‐MH‐HSI ): Development and validity evidence

   https://doi.org/10.1002/jee.20615  

   Hammer, Joseph H; Wright, Courtney J; Miller, Melanie E; Wilson, Sarah A (October 2024, Journal of Engineering Education)

   Abstract BackgroundUndergraduate engineering students experiencing distress are less likely than peers to ask for professional help. A population‐specific instrument to facilitate the identification of factors that influence mental healthcare utilization could guide development and testing of interventions to increase help seeking. PurposeWe used mixed methods guided by the Integrated Behavioral Model (IBM) to develop and evaluate the Undergraduate Engineering Mental Health Help‐Seeking Instrument (UE‐MH‐HSI). MethodFirst, we adapted existing measures of mental health help‐seeking intention and mechanisms (i.e., attitudes, perceived norm: injunctive, perceived norm: descriptive, personal agency: autonomy, personal agency: capacity). Second, we coded qualitative interviews (N = 33) to create population‐specific mental health help‐seeking belief measures (i.e., outcome beliefs, experiential beliefs, beliefs about others' expectations, beliefs about others' behavior, beliefs about barriers and facilitators). Third, we tested the psychometric properties using data from 596 undergraduate engineering students at a historically White, research‐focused institution in southern United States. ResultsPsychometric analyses indicated that (1) help‐seeking mechanism and intention measures demonstrated unidimensionality, internal consistency, construct replicability, and sufficient variability; (2) mechanism measures demonstrated criterion evidence of validity; and (3) most items within the belief measures demonstrated sufficient variability and convergent evidence of validity. ConclusionsThe UE‐MH‐HSI is an evidence‐based tool for investigating mental health help‐seeking factors and their relationship to help‐seeking behavior, well‐being, academic success, and engineering identity formation. Guidelines for use are provided. 

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5. Investigating Perceptions that Predict Mental Health Related Help-Seeking in First-Year Engineering Students

   Wilson, Sarah A; Huth, Ava; Lamer, Sara; Hammer, Joseph H; Whitwer, Matthew (August 2024, American Society for Engineering Education)

   National data indicates that engineering students are less likely than students in other academic disciplines to seek professional help for their mental health distress. Without professional intervention, mental health symptoms can worsen and become more challenging to treat. Therefore, this study uses a quantitative approach to investigate the beliefs that first-year engineering students hold about seeking mental health treatment and the influence of these beliefs on their intention to seek professional help. This study addresses the following research questions: 1) Which factors are most strongly associated with first-year engineering students’ intention to seek mental health treatment? 2) What beliefs about the outcomes of professional mental healthcare are most predictive of students’ intention to seek treatment? This study used a self-report survey instrument that employed the Integrated Behavioral Model (IBM) as an empirically supported theoretical framework to identify the beliefs that most accurately predict behavior. In December 2021, a survey was conducted in the first-year engineering program at a large public university with a predominantly White population (n = 452). The self-report survey instrument included measures of mental health help-seeking intention, attitude, perceived norm, personal agency, and outcome beliefs guided by the IBM. Respondents exhibited high scores on scales measuring their attitude towards seeking help, perceived control, and self-efficacy. This suggests that, on average, first-year engineering students had positive perceptions of their seeking help, felt in control of their decisions to seek help, and were confident in their ability to seek help. Students had lower scores for perceived norms, meaning they were less likely to believe that seeking help was supported by those who are important to them. Additionally, less than half of the students indicated they would intend to seek help if they experienced mental health distress. Students’ perception that others would expect them to seek help (i.e., their perceived norm injunctive) was the strongest predictor of intention to seek help, followed by their attitude toward seeking help. The specific outcome beliefs that were negatively correlated with intention to seek help were that seeking help would: 1) go against the expectations of the engineering community, 2) be a sign of weakness or an admission of defeat, and 3) result in poor treatment or discrimination from the mental health professional. Conversely, the outcome beliefs most positively correlated with intention were that seeking help would: 1) help me feel supported, 2) help me improve my coping skills, 3) make me feel better, 4) help me find a solution to my problem, and 5) help me gain a better understanding of my mental health concern. The findings of this study offer valuable insights into the beliefs of first-year engineering students towards seeking professional treatment for mental health concerns. These findings will inform the development of targeted interventions to improve help-seeking for mental health. 

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