Insects

The genus Peirates comprises important predatory assassin bugs that serve as vital biological control agents against agricultural and forestry pests. Thus, accurate species identification is critical for the utilization of these natural enemies. An integrative taxonomic approach was adopted to redefine the species boundaries among P. atromaculatus (Stål, 1870), P. turpis Walker, 1873, and P. fulvescens Lindberg, 1939, which were three related species differentiated by hemelytral color patterns. The COI-based K2P pairwise distances among the three nominal species (range: 0.00–2.61%) were similar to intraspecific variation, with no clear genetic separation between the three morphs. Multi-locus phylogenetic reconstructions derived from mitochondrial and nuclear ribosomal DNA sequencing revealed that individuals from the three color morphs were intermixed within a single evolutionary clade. In addition, geometric morphometric analyses of male genitalia demonstrated extensive overlapping in the shape space. The morphological datasets showed no distinct shape variations across the right paramere, left paramere, median pygophore process, and lateral phallothecal sclerite among the examined specimens. Based on the congruence between the molecular and morphometric results, P. turpissyn. nov. and P. fulvescenssyn. nov. are formally treated as the junior synonyms of P. atromaculatus in accordance with the Principle of Priority in zoological nomenclature, as P. atromaculatus is the oldest available name among the three taxa. A revised and comprehensive redescription of P. atromaculatus incorporating these color variations is provided.

Hematophagous arthropods and associated pathogens are becoming more prevalent globally. With limited treatment options, prevention is the top priority to reduce disease. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) has emerged as a standard detection method for many laboratories, but it has several drawbacks. Degraded sample quality, failed RNA preparations, and the presence of reaction inhibitors can lead to false negative results, introducing the need for a positive control. Existing control methods rely on adding exogenous nucleotides during amplification reactions, which may not reflect the quality of the sample. Incorporating assays to detect endogenous mosquito mRNA transcripts provides assurance that sample quality is sufficient for the downstream amplification of pathogen RNA. In the present study, we applied the Rapid Amplification of cDNA Ends (RACE) technique to obtain a full-length calreticulin cDNA sequence from the Culex restuans mosquito, collected in Massachusetts, USA. We then used the newly discovered cDNA sequence to design primers and probes spanning the first exon–exon junction of the calreticulin gene, which allowed for specific and accurate RNA transcript detection in an RT-qPCR assay. This assay detected the presence of calreticulin transcripts in extracted pools of mosquito RNA. This approach may be further developed to include other relevant mosquito species and, with extensive validation, may have potential for use as an endogenous control in arbovirus surveillance.

Choosing among predatory mites for controlling the two-spotted spider mite, Tetranychus urticae, still relies largely on empirical rules. We propose the Predation Potential Ranking Index (PPRI), a laboratory-derived index: the ratio of the predator’s to the prey’s intrinsic rate of increase (r_m) multiplied by the predator’s daily prey consumption. We applied it to Phytoseiulus persimilis and Neoseiulus californicus at 20, 25 and 30 °C, using age-stage, two-sex life tables and daily predation assays. Mean r_m across temperatures was 0.179 d⁻¹ for T. urticae, 0.204 d⁻¹ for P. persimilis and 0.226 d⁻¹ for N. californicus. The predator-to-prey ratio ranged from 1.01 to 1.49, and its 95% CI included 1 at 30 °C for both predators. Mean daily consumption by adult females was 12.45 and 9.36 prey. PPRI was 14.44 (95% CI [13.68–15.20]) for P. persimilis and 12.05 ([11.31–12.80]) for N. californicus; the difference (2.39, [1.46–3.32]) was supported at 20 °C (2.86, [1.25–4.47]) and 30 °C (3.64, [2.13–5.15]) but not at 25 °C (0.67, [−1.07–2.41]), and arose from consumption, not from the r_m ratio. PPRI assumes non-limiting prey and constant conditions and ignores density dependence. It is a screening and ranking tool, not a release-rate calculator, and requires greenhouse and field validation.