The Efficacy of Yeast Phagostimulant Baits in Attract-and-Kill Strategies Varies between Summer- and Winter-Morphs of Drosophila suzukii.

Drosophila suzukii (Matsumura), is a globally invasive pest of soft and stone fruit. To survive winter in temperate zones it enters a reproductive diapause in a morphologically distinct phenotype. Phagostimulant baits can be combined with insecticides in attract-and-kill strategies for control. We investigated the effectiveness of single yeast species and combinations of co-fermented yeast phagostimulant baits when combined with insecticides in laboratory assays against both summer- and winter-morph D. suzukii. Candida zemplininia or Hanseniaspora uvarum + C. zemplininia combined with lambda-cyhalothrin or cyantraniliprole, and H. uvarum combined with cyantraniliprole caused significantly higher mortality in winter- compared to summer-morph D. suzukii. Additionally, lambda-cyhalothrin combined with M. pulcherrima + H. uvarum resulted in greater mortality compared to single yeasts, H. uvarum for both summer- and winter-morphs and C. zemplininia for summer-morphs. M. pulcherrima + H. uvarum with spinosad significantly reduced the time-to-kill (50%) of summer-morphs compared to insecticide alone. Most yeast-based baits were comparable in terms of attract-and-kill efficacy to Combi-protec, a commercially available bait, although M. pulcherrima or H. uvarum + C. zemplininia in with cyantraniliprole were less effective. Our study suggests that yeast phagostimulants in attract-and-kill strategies should be adjusted for summer- and winter-morph D. suzukii for more effective control.

The relative abundances of yeasts attractive to Drosophila suzukii differ between fruit types and are greatest on raspberries.

Fungal metabolic volatiles attract Drosophila suzukii which oviposits in ripening fruits, but there are few data describing the fungal microbiomes of commercial fruits susceptible to this insect pest. We tested the hypothesis that fruit type and ripening stage have a significant effect on fruit surface fungal communities using DNA metabarcoding approaches and found strong support for differences in all three fungal community biodiversity metrics analysed (numbers, types, and abundances of taxa). There was an average fivefold greater difference in fungal communities between sites with different fruit types (strawberry, cherry, raspberry, and blueberry) than across fruit developmental stages, demonstrating site and/or fruit type is the greater factor defining fungal community assemblage. The addition of a fungal internal standard (Plectosphaerella cucumerina) showed cherry had relatively static fungal populations across ripening. Raspberry had a greater prevalence of Saccharomycetales yeasts attractive to D. suzukii, including Hanseniaspora uvarum, which aligns with reports that raspberry is among the fruits with greatest susceptibility and attraction to D. suzukii. Greater knowledge of how yeast communities change during fruit maturation and between species or sites may be valuable for developing methods to manipulate fruit microbiomes for use in integrated pest management strategies to control D. suzukii.

Field Suppression of Spotted Wing Drosophila (SWD) (Drosophila suzukii Matsumura) Using the Sterile Insect Technique (SIT).

Drosophila suzukii (spotted wing drosophila­SWD) is an economically important pest of soft and stone fruit worldwide. Control relies on broad-spectrum insecticides, which are neither fully effective nor environmentally sustainable. The sterile insect technique (SIT) is a proven, effective and environmentally friendly pest-management tool. Here, we investigated, for the first time, the potential of using SIT to control D. suzukii in field conditions without physical barriers that limit insect invasion. A proprietary method of rearing and irradiation with X-rays was used to obtain males that were > 99% sterile. Sterile males were released twice per week from April to October 2021 on a site in Kent, UK, where everbearing strawberries were grown in open polytunnels. The infestation of wild female D. suzukii was monitored weekly using red sticky traps with dry lure at the treated site and at two similar control sites that did not receive sterile male releases. Releases of sterile males suppressed the wild female D. suzukii population by up to 91% in comparison with the control sites. We thus demonstrated the feasibility of SIT to achieve season-long control of D. suzukii using early, sustained and dynamically targeted releases of sterile males. This provides a promising environmentally friendly method to control this important pest.

The role of motion tracking in assessing technical skill acquisition using a neonatal 3D-printed thoracoscopic esophageal atresia/tracheo-esophageal fistula simulator.

INTRODUCTION: Acquiring the technical skills required for thoracoscopic repair of esophageal atresia with tracheo-esophageal fistula (EA/TEF) is challenging. A high-fidelity 3D-printed pediatric thoracoscopic EA/TEF simulator has been developed to address this issue. This study explored motion-tracking as an assessment tool to distinguish between surgeons of different expertise using the simulator. METHODS: Participants performed a single intracorporeal suture between the esophageal ends in EA with TEF. Total relative path lengths of the right and left surgical instruments were recorded during the task. Each video-recorded attempt was assessed by a blinded pediatric surgeon using a modified Objective Structured Assessment of Technical Skills (OSATS) score. Data recorded as median (range) and statistical significance as p<0.05. RESULTS: The task was performed by 17 participants. The median OSATS scores identified a significant difference between experts and novices. A difference between left- and right-hands was only found in the mid-skill level group. Right-hand path length was greatest in novices and lowest in experts. Left-hand path length was greatest in novices and the mid-skill level group compared to experts. CONCLUSION: Experts had the lowest total path length for either hand, suggesting they had the greatest efficiency of movement. The similar high path lengths in both hands for novices indicate their relatively low level of skill with either hand. The difference between right- and left-hand path lengths in the mid-skill level group likely reflects the improved right-handed technical skills in contrast to the still developing left hand. Further focus on the left hand during simulation training may improve left-handed economy of movement.

Master and Apprentice or a Slave to Technology? A Randomized Controlled Trial of Minimal Access Surgery Simulation-Based Training Techniques.

Introduction: This study set out to assess the efficacy of three different approaches to simulation-based minimal access surgery (MAS) training using a three-dimensional printed neonatal thoracoscopic simulator and a virtual simulator. Materials and Methods: Randomized controlled trial of medical students (N = 32), as novices to MAS. The participants performed two construct validated tasks on a thoracoscopic simulator and were then randomly allocated into four intervention groups: (1) three consultant-led sessions on a thoracoscopic simulator; (2) three self-directed learning sessions on the same simulator; (3) self-directed "virtual training" on the "SimuSurg" application; and (4) control. Postintervention participants repeated both tasks. Videos of all task attempts were de-identified and marked by a blinded consultant pediatric surgeon. Results: There were no statistically significant differences in baseline objective structured assessment of technical skills (OSATS) scores or demographics in any group. For the "ring transfer" task, Groups 1 and 2 showed significant improvement after intervention, with no significant change in Groups 3 or 4. There was no significant difference between Groups 1 or 2 in postintervention scores. For the "needle pass" task, no group demonstrated a statistically significant improvement after intervention. Conclusion: Practice on a physical simulator either consultant-led or self-directed led to improved scores for MAS novices compared with a virtual simulator or no intervention for a simple "ring transfer" task. This suggests that time on the physical simulator was the most important factor and implies that trainees could usefully practice simple tasks at their convenience rather than require consultant supervision. This improvement is not seen in more challenging tasks such as the "needle pass."

Are Drosophila preferences for yeasts stable or contextual?

Whether there are general mechanisms, driving interspecific chemical communication is uncertain. Saccharomycetaceae yeast and Drosophila fruit flies, both extensively studied research models, share the same fruit habitat, and it has been suggested their interaction comprises a facultative mutualism that is instigated and maintained by yeast volatiles. Using choice tests, experimental evolution, and volatile analyses, we investigate the maintenance of this relationship and reveal little consistency between behavioral responses of two isolates of sympatric Drosophila species. While D. melanogaster was attracted to a range of different Saccharomycetaceae yeasts and this was independent of fruit type, D. simulans preference appeared specific to a particular S. cerevisiae genotype isolated from a vineyard fly population. This response, however, was not consistent across fruit types and is therefore context-dependent. In addition, D. simulans attraction to an individual S. cerevisiae isolate was pliable over ecological timescales. Volatile candidates were analyzed to identify a common signal for yeast attraction, and while D. melanogaster generally responded to fermentation profiles, D. simulans preference was more discerning and likely threshold-dependent. Overall, there is no strong evidence to support the idea of bespoke interactions with specific yeasts for either of these Drosophila genotypes. Rather the data support the idea Drosophila are generally adapted to sense and locate fruits infested by a range of fungal microbes and/or that yeast-Drosophila interactions may evolve rapidly.

Dose-dependent behavioural fever responses in desert locusts challenged with the entomopathogenic fungus Metarhizium acridum.

Behavioural fever is a common response to immune challenge in ectotherms and confers survival benefits. However, costs accrue rapidly as body temperature rises. Thus, the magnitude of adaptive fever responses might reflect the balance of costs and benefits. We investigated behavioural fever in desert locusts, Schistocerca gregaria, infected with the entomopathogenic fungus Metarhizium acridum. We first tracked the time course of behavioural fever in infected locusts, demonstrating that body temperatures rose on the day following inoculation (day 1), and reached peak intensity on the day after that (day 2). Subsequently, the magnitude of fever responses varied during a day, and locusts tended to exhibit high-intensity fever responses in the mornings when basking was first possible. We speculate that this may have resulted from increased fungal load caused by unimpeded growth overnight when locusts could not fever. We next inoculated locusts with different M. acridum doses ranging from 0 to ca. 75,000 conidia. The magnitude of their behavioural fever responses on day 2 post-inoculation was positively related to fungal dose. Thus, we demonstrate dose-dependency in the behavioural fever responses of desert locusts and suggest that this may reflect the adaptive deployment of behavioural fever to minimize costs relative to benefits.