Annual Review of Entomology

Insect heat shock proteins include ATP-independent small heat shock proteins and the larger ATP-dependent proteins, Hsp70, Hsp90, and Hsp60. In concert with cochaperones and accessory proteins, heat shock proteins mediate essential activities such as protein folding, localization, and degradation. Heat shock proteins are synthesized constitutively in insects and induced by stressors such as heat, cold, crowding, and anoxia. Synthesis depends on the physiological state of the insect, but the common function of heat shock proteins, often working in networks, is to maintain cell homeostasis through interaction with substrate proteins. Stress-induced expression of heat shock protein genes occurs in a background of protein synthesis inhibition, but in the course of diapause, a state of dormancy and increased stress tolerance, these genes undergo differential regulation without the general disruption of protein production. During diapause, when ATP concentrations are low, heat shock proteins may sequester rather than fold proteins.

▪ Abstract  The P450 enzymes (mixed function oxidases, cytochrome P450 monooxygenases), a diverse class of enzymes found in virtually all insect tissues, fulfill many important tasks, from the synthesis and degradation of ecdysteroids and juvenile hormones to the metabolism of foreign chemicals of natural or synthetic origin. This diversity in function is achieved by a diversity in structure, as insect genomes probably carry about 100 P450 genes, sometimes arranged in clusters, and each coding for a different P450 enzyme. Both microsomal and mitochondrial P450s are present in insects and are best studied by heterologous expression of their cDNA and reconstitution of purified enzymes. P450 genes are under complex regulation, with induction playing a central role in the adaptation to plant chemicals and regulatory mutations playing a central role in insecticide resistance. Polymorphisms in induction or constitutive expression allow insects to scan their P450 gene repertoire for the appropriate response to chemical insults, and these evolutionary pressures in turn maintain P450 diversity.

▪ Tóm tắt: Bacillus thuringiensis (Bt) là một nguồn protein diệt côn trùng quý giá, được sử dụng trong các công thức phun thông thường và trong các loại cây trồng chuyển gen. Đây là lựa chọn thay thế đầy hứa hẹn nhất cho thuốc trừ sâu tổng hợp. Tuy nhiên, sự phát triển của sức đề kháng trong quần thể côn trùng là một mối đe dọa nghiêm trọng đối với công nghệ này. Cho đến nay, chỉ có một loài côn trùng phát triển đáng kể khả năng kháng cự trên thực địa, nhưng các thí nghiệm chọn lọc trong phòng thí nghiệm đã cho thấy tiềm năng cao của các loài khác trong việc phát triển khả năng kháng cự Bt. Chúng tôi đã tổng hợp kiến thức hiện nay về các cơ chế sinh hóa và di truyền của sự kháng cự đối với sản phẩm Bt và các protein tinh thể diệt côn trùng. Việc hiểu biết về cơ sở sinh hóa và di truyền của sự kháng cự Bt có thể giúp thiết kế các chiến lược quản lý phù hợp nhằm trì hoãn hoặc giảm sự phát triển của khả năng kháng cự trong quần thể côn trùng.

Many of the most harmful parasitic diseases are transmitted by blood-feeding insect vectors. During this stage of their life cycles, selection pressures favor parasites that can manipulate their vectors to enhance transmission. Strategies may include increasing the amount of contact between vector and host, reducing vector reproductive output and consequently altering vector resource management to increase available nutrient reserves, and increasing vector longevity. Manipulation of these life-history traits may be more beneficial at some phase of the parasite's developmental process than at others. This review examines empirical, experimental, and field-based evidence to evaluate examples of changes in vector behavior and physiology that might be construed to be manipulative. Examples are mainly drawn from malaria-infected mosquitoes, Leishmania-infected sandflies, and Trypanosoma-infected tsetse flies.

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the most important pest of citrus worldwide because it serves as a vector of “Candidatus Liberibacter” species (Alphaproteobacteria) that cause huanglongbing (citrus greening disease). All commercially cultivated citrus is susceptible and varieties tolerant to disease expression are not yet available. Onset of disease occurs following a long latent period after inoculation, and thus the pathogen can spread widely prior to detection. Detection of the pathogen in Brazil in 2004 and Florida in 2005 catalyzed a significant increase in research on D. citri biology. Chemical control is the primary management strategy currently employed, but recently documented decreases in susceptibility of D. citri to several insecticides illustrate the need for more sustainable tools. Herein, we discuss recent advances in the understanding of D. citri biology and behavior, pathogen transmission biology, biological control, and chemical control with respect to “Candidatus Liberibacter asiaticus.” Our goal is to point toward integrated and biologically relevant management of this pathosystem.