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The magnitude and functional patterns of intraspecific transcriptional variation in the anophelines, including those of sex-biased genes underlying sex-specific traits relevant for malaria transmission, remain understudied. As a result, how changes in expression levels drive adaptation in these species is poorly understood. We sequenced the female, male, and larval transcriptomes of three populations of Anopheles arabiensis from Burkina Faso. One-third of the genes were differentially expressed between populations, often involving insecticide resistance-related genes in a sample type-specific manner, and with the females showing the largest number of differentially expressed genes. At the genomic level, the X chromosome appears depleted of differentially expressed genes compared with the autosomes, chromosomes harboring inversions do not exhibit evidence for enrichment of such genes, and genes that are top contributors to functional enrichment patterns of population differentiation tend to be clustered in the genome. Further, the magnitude of variation for the sex expression ratio across populations did not substantially differ between male- and female-biased genes, except for some populations in which male-limited expressed genes showed more variation than their female counterparts. In fact, female-biased genes exhibited a larger level of interpopulation variation than male-biased genes, both when assayed in males and females. Beyond uncovering the extensive adaptive potential of transcriptional variation in An. Arabiensis, our findings suggest that the evolutionary rate of changes in expression levels on the X chromosome exceeds that on the autosomes, while pointing to female-biased genes as the most variable component of the An. Arabiensis transcriptome.

Background: The WHO Global Malaria Programme advocates for a comprehensive, strategic approach to managing insecticide resistance, highlighting the importance of using multiple insecticides with different modes of action through rotations and combinations. To slow the spread of resistance, it is essential to develop and evaluate new formulations that feature unique modes of action and extended residual effects. Addressing this need, Mitsui Chemicals Crop & Life Solutions, Inc., developed VECTRON™ T500, a new indoor residual spraying (IRS) formulation using broflanilide, applied at a dosage of 100 mg AI/m2. This formulation was tested in a Phase III community trial, alongside Actellic® 300CS, a commonly used IRS product containing pirimiphos-methyl, applied at the recommended dosage of 1000 mg AI/m2. Methods: Monthly WHO wall cone bioassays were performed to assess the efficacy of the interventions using three mosquito strains: the laboratory-bred, insecticide-susceptible Anopheles gambiae s.s. Kisumu strain, the insecticide-resistant Anopheles coluzzii VKPer strain, and wild Anopheles gambiae s.l. mosquitoes from the Vallée du Kou, where the study was conducted. Vector surveillance was carried out to compare the results between sites treated with VECTRON™ T500, Actellic® 300CS, and an untreated control site. In addition, any reported adverse effects were closely monitored to evaluate the community's acceptance of VECTRON™ T500. Results: VECTRON™ T500 consistently achieved 100% mortality across all wall types for both susceptible and resistant mosquito strains over the 12-month period. In comparison, Actellic® 300CS induced < 80% mortality for both strains, irrespective of the wall substrate. When assessing delayed mortality in An. gambiae s.l. mosquitoes collected from sites treated with Actellic® 300CS (VK1) and VECTRON™ T500 (VK3), a statistically significant difference was noted after a 72-h holding period compared to the control site (RR = 0.51, CI95% = [0.31–0.6], P = 0.0026). Additionally, no adverse events were reported in households sprayed with VECTRON™ T500. Conclusions: The residual efficacy of VECTRON™ T500 extended for 12 months post-spraying, effectively covering the full malaria transmission season while maintaining high mortality rates in pyrethroid-resistant malaria vectors. VECTRON™ T500 demonstrated non-inferiority in performance compared to Actellic® 300CS, the standard reference product. This new IRS formulation has the potential to play a crucial role in managing insecticide resistance by being integrated into a rotational strategy alongside other IRS products containing insecticides with different modes of action. [ABSTRACT FROM AUTHOR]

The Oriental fruit fly, Bactrocera dorsalis, is a pest of significant economic interest that damages horticulture and causes major economic losses worldwide. The main control measures are based on insecticides, which are being increasingly restricted due to the development of genetic resistance. Therefore, there is a crucial need for a novel, sustainable, and environmentally safe means of controlling this pest. Advances in genome editing, aided by the discovery of CRISPR‐Cas9 tools and the development of gene drive systems, offer new alternatives for combating insect pests and vectors. Genetic suppression tools targeting key parameters could become powerful assets within the AW‐IPM programme for controlling B. dorsalis. This literature review provides an overview of currently characterized genes that could be targeted for genetic suppression of B. dorsalis. [ABSTRACT FROM AUTHOR]

Anopheles gambiae and its sibling species Anopheles coluzzii are the most efficient vectors of the malaria parasite Plasmodium falciparum. When females of these species feed on an infected human host, oogenesis and parasite development proceed concurrently, but interactions between these processes are not fully understood. Using multiple natural P. falciparum isolates from Burkina Faso, we show that in both vectors, impairing steroid hormone signaling to disrupt oogenesis leads to accelerated oocyst growth and in a manner that appears to depend on both parasite and mosquito genotype. Consistently, we find that egg numbers are negatively linked to oocyst size, a metric for the rate of oocyst development. Oocyst growth rates are also strongly accelerated in females that are in a pre-gravid state, i.e. that fail to develop eggs after an initial blood meal. Overall, these findings advance our understanding of mosquito-parasite interactions that influence P. falciparum development in malaria-endemic regions. Author summary: Malaria, an infectious disease caused by Plasmodium parasites, continues to affect millions of people each year. These parasites are transmitted by Anopheles mosquitoes during blood feeding, which is required by females to produce eggs. After they are ingested by the female, parasites start developing in the midgut at the same time as the mosquito initiates oogenesis, the process of egg development. Here, we investigated how the concomitant processes of egg and parasite development interact in field-derived Anopheles and Plasmodium isolates. We found that in these naturally occurring pairs, oogenesis is negatively linked to parasite development, such that mosquitoes producing fewer eggs harbor faster growing oocysts. Furthermore, when we disrupt signaling pathways that drive oogenesis, oocyst growth is accelerated in a manner that appears to depend on both mosquito and parasite genotype. Additionally, when field mosquitoes fail to develop eggs, they are likely to have faster growing oocysts. The interaction between key mosquito and parasite developmental processes revealed here underscores how intimately linked Plasmodium are to mosquito physiology and can help inform the development of future vector control tools that are both safe and effective. [ABSTRACT FROM AUTHOR]