Insects

Aedes albopictus is an important vector of several arboviruses and has expanded its distribution throughout Latin America and the Caribbean in recent decades. Despite its increasing epidemiological relevance, data on insecticide resistance in this region remain limited compared to Aedes aegypti. This review compiled and analyzed the published evidence on this topic across the region. A literature search was conducted in PubMed, SciELO, Google Scholar, LILACS, and DOAJ, using combinations of the terms “insecticide resistance” or “insecticide susceptibility” plus “Aedes albopictus”, and the names of all countries recognized by the United Nations as part of the region. Studies published until May 2025 were considered, regardless of the publication year. Following the core PRISMA principles adapted for this review, 33 studies were identified, of which 17 met the inclusion criteria. Results indicate recurrent but uneven reports of resistance, with organophosphates being the most frequently evaluated insecticide (33.9%), followed by pyrethroids (27.7%) and carbamates (10.8%), and metabolic mechanisms being the most implicated. Evidence suggests that control actions focused on Ae. aegypti may also impose selective pressure over Ae. albopictus. Overall, the resistance found on Ae. albopictus emphasizes the need for expanded and standardized surveillance to support effective vector control across the Americas.

Climate warming puts new selective pressures on natural populations, but there are few quantitative measurements of selection in natural populations over protracted time periods. Observations made at the beginning and end ofa 47-year cumulative increase of 2.7 °C in the mean September temperature in Northern Minnesota, USA, permit quantitative estimation of selection against a suite of alleles at a single locus determining the expressionof dark color forms in populations of the meadow spittlebug, Philaenus spumarius (L.) (Hemiptera: Cercopoidea: Aphrophoridae). Alternative methods of estimation of the selection coefficient s, a measure of the intensity of selection, produce values of s = 0.0125 and 0.0218, respectively, corresponding to a disadvantage of about one to two percent per year or, since P. spumarius is univoltine, per round of selection. The existence of a locus under selection presents an opportunity for molecular localization and characterization of the genetic locus determining color form. Philaenus spumarius is of particular interest in Europe, as it is the major local vector of the bacterial plant pathogen Xylella fastidiosa.

The endoplasmic reticulum (ER) stress response, or unfolded protein response (UPR), is crucial for cellular homeostasis and host defense. Its role in insect vectors of plant pathogens remains poorly understood. This study conducted a comprehensive molecular characterization of three core UPR genes—BiP, IRE1, and XBP1—in Diaphorina citri, the insect vector of the citrus huanglongbing pathogen Candidatus Liberibacter asiaticus (CLas). Expression profiling showed distinct developmental and tissue-specific patterns for these genes. The IRE1-mediated unconventional splicing of XBP1 mRNA was identified in D. citri and predicted across diverse insect pests. A semi-quantitative RT-PCR assay was established to detect this splicing event for monitoring ER stress. Time-course analysis of CLas-infected D. citri revealed an early activation (upregulation of BiP, IRE1, XBP1 transcripts, and increased XBP1 splicing) followed by later suppression of the UPR. Functional studies demonstrated that induction of ER stress with thapsigargin increased CLas titer. RNAi-mediated silencing showed that IRE1 silencing increased CLas proliferation, whereas XBP1 silencing reduced it. These findings provide foundational insights into the ER stress pathway in D. citri and demonstrate that the IRE1-XBP1 branch of the UPR plays a critical role in modulating CLas infection dynamics within its insect vector.