Mosquito-borne infectious diseases, such as malaria, respond to environmental change in a complex way because the transmission of Plasmodium depends on a set of context-specific ecological and social factors that influence mosquito vectors and humans differently. Malaria continues to be a serious public health problem for populations living in and near the tropical humid forest of the Amazon region, where evidence suggests that deforestation of the Amazon forest has been the main environmental driver of persistent epidemics. In this review, we focus on the impact of increasing forest degradation on the ecology of anopheline vectors and how aspects of mosquito population dynamics, such as abundance and the rate of human-vector contact, may mediate the relationship between environmental transformation and malaria risk. We also discuss the increasingly important role of regional zoonotic malaria. The sustainability of the malaria elimination strategy in the Americas will require a better understanding of the adaptation of mosquitoes to increasing anthropogenic pressures on the Amazon rainforest.

Pharmaceuticals and personal care products (PPCP) are omnipresent in our daily lives, and these emerging contaminants require increasing attention. PPCP and their metabolites are found in treated wastewater and in biosolids resulting from wastewater treatment, thus providing routes for dissemination to soils, freshwater, and groundwater, with subsequent consequences for insects. This review explores the effects of PPCP on the molecular, physiological, and biological (including behavior) responses of insects and consequences for their microbiota. As several PPCP can bioaccumulate in insects, in particular in aquatic ones, their roles in the transfer of the drugs to riparian and terrestrial food web are discussed, as well as community-level consequences. We propose future research directions to better appreciate the side effects and unintended effects of medication on insects. Attention should be given to the effects of PPCP on insects in environmentally realistic scenarios with relevant concentrations, in combination with other environmental pollutants, and with durations of exposure.

Leaf-cutting ants, which comprise more than 50 species distributed from Patagonia to North America, build the largest nests among ants. Workers forage plant fragments to cultivate a symbiotic fungus inside underground chambers, which serves as the primary food source for the colony. While digging the nest, workers respond to local cues such as soil temperature, moisture, and CO2 levels, resulting in the emergence of a nest architecture that provides a proper environment for fungus growth. Leaf-cutting ants have species-specific nest architectures, which evolved from a basal design consisting of a vertical tunnel and a few interconnected chambers. Some species developed, in addition, architectural innovations aimed at the control of both hygiene and nest climate, including waste chambers, ventilatory turrets, and a nest thatch. A fine-tuned climate control is achieved by the relocation of fungus gardens within the nest following the workers' environmental preferences and by nesting plasticity.

Thanks to the fast development of sequencing techniques and bioinformatics tools, sequencing the genome of an insect species for specific research purposes has become an increasingly popular practice. Insect genomes not only provide sets of gene sequences but also represent a change in focus from reductionism to systemic biology in the field of entomology. Using insect genomes, researchers are able to identify and study the functions of all members of a gene family, pathway, or gene network associated with a trait of interest. Comparative genomics studies provide new insights into insect evolution, addressing long-lasting controversies in taxonomy. It is also now feasible to uncover the genetic basis of important traits by identifying variants using genome resequencing data of individual insects, followed by genome-wide association analysis. Here, we review the current progress in insect genome sequencing projects and the application of insect genomes in uncovering the phylogenetic relationships between insects and unraveling the mechanisms of important life-history traits. We also summarize the challenges in genome data sharing and possible solutions. Finally, we provide guidance for fully and deeply mining insect genome data.

Most insects encountered in the field are initially entomological dark matter in that they cannot be identified to species while alive. This explains the enduring quest for efficient ways to identify collected specimens. Morphological tools came first but are now routinely replaced or complemented with DNA barcodes. Initially too expensive for widespread use, these barcodes have since evolved into powerful tools for specimen identification and sorting, given that the evolution of sequencing approaches has dramatically reduced the cost of barcodes, thus enabling decentralized deployment across the planet. In this article, we review how DNA barcodes have become a key tool for accelerating biodiversity discovery and analyzing insect communities through both megabarcoding and metabarcoding in an era of insect decline. We predict that DNA barcodes will be particularly important for assembling image training sets for deep learning algorithms, global biodiversity genomics, and functional analysis of insect communities.

Insect pests and insect pest management tactics impose risks to the environment. Environmental risk assessment is a formalized paradigm for the objective evaluation of risk in which assumptions and uncertainties are clearly presented. Therefore, a better understanding of the environmental risks and especially the comparative risks posed by insect pests and management tactics will improve integrated pest management. Risk assessments for insect pest management tactics are much more common for pesticides and genetically engineered crops than for biological control, cultural control, and semiochemicals. The reasons for this discrepancy include evidence of deleterious effects and data availability for pesticides and genetically engineered crops, public perceptions of tactics, and politics. Regardless of the regulatory oversight and frequency of risk assessments, all tactics should be subject to the risk assessment paradigm to assist in societal decisions.

Major changes in genetic variation are generally considered deleterious to populations. The massive biodiversity of insects distinguishes them from other animal groups. Insect deviant effective population sizes, alternative modes of reproduction, advantageous inbreeding, endosymbionts, and other factors translate to highly specific inbreeding and outbreeding outcomes. We review the evidence for inbreeding and outbreeding depression and consequences across wild and captive insect populations, highlighting conservation, invasion, and commercial production entomology. We not only discern patterns but also explain why they are often inconsistent or absent. We discuss how insect inbreeding and outbreeding depression operates in complex, sometimes contradictory directions, such as inbreeding being detrimental to individuals but beneficial to populations. We conclude by giving recommendations to (a) more comprehensively account for important variables in insect inbreeding and outbreeding depression, (b) standardize the means of measuring genetic variation and phenotypic impacts for insect populations so as to more reliably predict when inbreeding or outbreeding depression applies, and (c) outline possible remediation options, both nongenetic and genetic, including revision of restrictive international trade laws.

Bacteriocytes are host cells specialized to harbor symbionts in certain insect taxa. The adaptation, development, and evolution of bacteriocytes underlie insect symbiosis maintenance. Bacteriocytes carry enriched host genes of insect and bacterial origin whose transcription can be regulated by microRNAs, which are involved in host-symbiont metabolic interactions. Recognition proteins of peptidoglycan, the bacterial cell wall component, and autophagy regulate symbiont abundance in bacteriocytes. Horizontally transferred genes expressed in bacteriocytes influence the metabolism of symbiont peptidoglycan, which may affect the bacteriocyte immune response against symbionts. Bacteriocytes release or transport symbionts into ovaries for symbiont vertical transmission. Bacteriocyte development and death, regulated by transcriptional factors, are variable in different insect species. The evolutionary origin of insect bacteriocytes remains unclear. Future research should elucidate bacteriocyte cell biology, the molecular interplay between bacteriocyte metabolic and immune functions, the genetic basis of bacteriocyte origin, and the coordination between bacteriocyte function and host biology in diverse symbioses.

Palm weevils, Rhynchophorus spp., are destructive pests of native, ornamental, and agricultural palm species. Of the 10 recognized species, two of the most injurious species, Rhynchophorus ferrugineus and Rhynchophorus palmarum, both of which have spread beyond their native range, are the best studied. Due to its greater global spread and damage to edible date industries in the Middle East, R. ferrugineus has received more research interest. Integrated pest management programs utilize traps baited with aggregation pheromone, removal of infested palms, and insecticides. However, weevil control is costly, development of resistance to insecticides is problematic, and program efficacy can be impaired because early detection of infestations is difficult. The genome of R. ferrugineus has been sequenced, and omics research is providing insight into pheromone communication and changes in volatile and metabolism profiles of weevil-infested palms. We outline how such developments could lead to new control strategies and early detection tools.

Spotted lanternfly, Lycorma delicatula (White), invaded the eastern United States in 2014 and has since caused economic and ecological disruption. In particular, spotted lanternfly has shown itself to be a significant pest of vineyards and ornamental plants and is likely to continue to spread to new areas. Factors that have contributed to its success as an invader include its wide host range and high mobility, which allow it to infest a wide range of habitats, including agricultural, urban, suburban, and managed and natural forested areas. Management is dependent on chemical use, although no single currently available control measure alone will be sufficient. Expected final online publication date for the Annual Review of Entomology, Volume 68 is January 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.