Resistance mechanisms to synthetic insecticides often include point mutations and increased expression of genes encoding detoxification enzymes. Since pyrethroids are the main adulticides used against Aedes aegypti, which vectors pathogens such as Zika virus, understanding resistance to this insecticide class is of significant relevance. We focused on adenosine triphosphate (ATP)-binding cassette (ABC) transporters in the pyrethroid-resistant Puerto Rico (PR) strain of Ae. aegypti. We investigated the expression patterns of six ABC transporters previously characterized as differentially expressed in insecticide-challenged mosquitoes, or increased mRNA expression in pyrethroid-resistant Ae. aegypti, by comparing PR to the Rockefeller (Rock) susceptible strain. No constitutive differential expression between strains was detected, but expression differences for these genes was influenced by sex and age, suggesting that their role is independent from resistance in PR. Instead, ABC transporters may be induced after insecticide exposure. Challenging mosquitoes with deltamethrin, with or without ABC transporter modulators, showed that Rock and PR responded differently, but a contribution of ABC transporters to deltamethrin toxicity is suspected. Moreover, the effect of dexamethasone, which enhanced the inhibition of nerve firing by deltamethrin, was observed using a Drosophila central nervous system preparation, showing synergy of these two compounds through the potential inhibition of ABC transporters.

Background: Food security is an increasingly pressing global issue, and by 2050, food production will not be sufficient to feed the growing population. Part of global food insecurity can be attributed to post-harvest losses, including quantity and quality losses caused by stored-product pests like insects. It is thus timely to find management strategies to mitigate these losses and counteract food insecurity. The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), a global stored-product pest with a wide range of food sources, was used in this study to assess repellency to a selection of essential oils. Methods: Multiple behaviorally relevant methods were used to determine the efficacy of the essential oils in assays to pinpoint the most promising repellents. Experiments were used to assess individual and group behaviors with or without airflow and examined the behavioral variation in distance moved and the time spent away from the oil. Results: It was found that exposure to essential oils and conditions of experimentation considerably influenced T. castaneum’s behavioral response, but a clear candidate for repellency could not be chosen based on the collected data. Conclusions: Follow-up research is needed to pinpoint repellents for integrated pest management practices to protect grains from stored-product pests and to justify their use in and around commodities.

At the 2019 annual meeting of the Entomological Society of America (ESA) in St Louis, I organized a symposium titled “Advocate Sharing: The Science of Unpublished Results in Entomology.” The goal was to focus on unpublished negative results, which we decided should not be considered negative, because all data can be useful, even when it isn’t the data we expected. Instead, we can consider the results as inconclusive, surprising, or unexpected. During the symposium, we heard about the science behind the work, the experiences of several researchers, and how they dealt with the unexpected and moved forward. This article is a summary of the topics covered during the symposium and the attendees’ opinions about publishing “negative” data. Sharing our experiences as students, postdocs, faculty, and researchers in industry and governmental agencies revealed that we all had dealt with common issues. All of us have anecdotes and stories about an experiment that never worked, no matter how much effort we put into it. We all have experience with a hypothesis that could never be verified due to a flawed experimental design, a lack of time, or insufficient funding to troubleshoot all aspects that could influence the results. Issues may even originate from our own misconceptions about what to expect from our experiments. During the presentations and discussion, we covered the following points.