Abstract Mosquitoes of the genus Toxorhynchites are specialized predators of container-breeding Aedes mosquito larvae. Despite their biocontrol potential, species boundaries and phylogenetic relationships remain poorly understood. Utilizing country-wide sampling across Panama, we evaluated the taxonomic status and diversity of local Toxorhynchites species. We collected 147 specimens from artificial and natural containers, yielding 97 cytochrome c oxidase subunit I (COI) barcodes from 101 sequenced individuals. A regional Neighbor-Joining (NJ) analysis revealed 4 distinct, well-supported clusters (I to IV) exhibiting high mean inter-cluster genetic divergence (4.8% to 20.2%), alongside clear morphological and ecological segregation. Subsequent global NJ, Maximum Likelihood (ML), and Bayesian analyses incorporating BOLD and GenBank sequences recovered Toxorhynchites as a strongly supported monophyletic group (posterior probability = 1.0). These analyses revealed a deep phylogenetic divergence separating Old World Tx. (Toxorhynchites; Clades A and B) from New World Tx. (Megarhina; Clades C to G) lineages, placing the split during the early Miocene at 22.29 million years ago (95% Highest Posterior Density [HPD]: 16.24 to 31.08 Ma). Panamanian Clusters I and II formed 2 distinct groupings within Clade G, nesting as sisters to Subclade G1, which is characterized by severe taxonomic discordance involving sequences labeled as Tx. moctezuma, Tx. theobaldi, and Tx. rutilus. Cluster III nested within Tx. hypoptes (1.5% divergence) in Clade E, whereas Cluster IV associated with Tx. haemorrhoidalis s.l. (>5.0% divergence) in Clade C. The high degree of taxonomic uncertainty and cryptic diversity uncovered within Clades C, D, and G underscores an urgent need for a formal taxonomic revision to accurately delimit species boundaries within the genus.
Tick-borne diseases are on the rise in the United States. As tick species differ with regards to the suites of human pathogens they transmit, species identification of ticks found biting people may be helpful in assessing tick-borne disease risk. However, neither the public nor medical professionals are well-versed in tick identification. Artificial intelligence (AI) assisted object identification applications are available on smartphones but their accuracy for identifying ticks of different species, life stages, and engorgement levels is unknown. We evaluated 3 applications freely available on both iOS and Android platforms: 1 generalist object identification application (Google Lens) and 2 applications focused on nature identification (Seek by iNaturalist, Obsidentify). These applications were tested for their ability to identify ticks across five different smartphones and associated smartphone users. The evaluation included 5 species of human-biting hard ticks: Amblyomma americanum (Linnaeus), Amblyomma maculatum Koch, Dermacentor variabilis (Say), Ixodes scapularis Say, and Rhipicephalus sanguineus (Latreille). Across all species, life stages, and engorgement levels, the overall identification accuracy was low with 54% of specimens correctly identified to taxonomic Order (Ixodida [ticks]) and 16% accurately identified to species. Accuracy was highest for unfed adult females but generally poor for unfed immature ticks and blood-fed specimens. Our study revealed a high degree of variation in identification accuracy among tick species, life stages and engorgement levels. Currently, these tools have limited utility in clinical settings, due to their low accuracy at the clinically-relevant genus and species taxonomic levels. Future testing is needed as these applications continue to evolve.
Estimation of the minimum postmortem interval (PMImin) based on forensic entomology is susceptible to interference from xenobiotics. This study explored the toxic impacts of Diphenidol and Diquat on the development of Chrysomya megacephala, a vital forensic fly species. Their effects were assessed on insect development, survival, and morphology to establish PMImin correction parameters for poisoning fatalities and improve the credibility of entomological evidence. Larvae were raised at 28 degrees C with diets containing Diphenidol (40, 80, and 160 mg/kg) and Diquat (25, 50, and 100 mg/kg), corresponding to 0.5 & times;, 1 & times;, and 2 & times; the estimated human LD50. An AB subgroup design was adopted to eliminate sampling bias. The two compounds exhibited fundamentally distinct toxicological profiles with implications for forensic practice. Diphenidol induced a complex, non-linear disruption, causing significant developmental delays (up to 23.33 h) without reducing overall survival. This pattern risks a covert underestimation of PMImin if insect development appears normal but is temporally shifted. In stark contrast, Diquat produced a clear, dose-dependent toxicity, severely retarding growth, reducing pupation and emergence success by up to 40%, and inducing a 6.9% teratogenicity rate at the highest concentration. These overt effects (stunted growth, low population recovery, and morphological anomalies) serve as direct warning signs of potential toxicant presence and associated PMImin estimation errors. This study's findings differentiate between hidden temporal delays and overt inhibitory toxicity, underscoring the imperative for integrated toxicological and entomological analysis to prevent critical misinterpretations of the forensic timeline.
The black bear, Ursus americanus (Carnivora: Ursidae), is a large mammal listed as threatened in the state of Mississippi since 1992. After years of historical decline, black bear numbers and their range have been increasing in Mississippi, with bears returning to areas within their historic range. Little is known about ectoparasites and vector-borne microorganisms associated with black bears. During 2024, 83 ticks comprising 4 species were removed from 17 bears (one of which was a recapture) captured in 9 central and southern Mississippi counties. Upon molecular screening of the 83 ticks, 11 specimens contained DNA of the Rickettsia endosymbiont of Ixodes scapularis (also known as Rickettsia buchneri); 20 contained Rickettsia parkeri; 21 had "Candidatus Rickettsia andeanae;" 9 had R. tillamookensis; 4 had R. amblyommatis; 1 had R. bellii; and 4 had organisms in the family Anaplasmataceae; of these, 1 was identified as Ehrlichia chaffeensis. Four ticks had detectable levels of Rickettsia DNA that could not be identified to the species level.
Evidence regarding seasonal variation in Demodex infestation and its association with dry eye disease (DED) remains limited. This study evaluated seasonal variation in Demodex infestation and DED and explored their relationship with environmental variables in a longitudinal cohort from Talca, Chile. A prospective longitudinal study was conducted among students and employees of Universidad Cat & oacute;lica del Maule, Chile. Participants underwent ocular examinations during four seasonal evaluations (summer, fall, winter, and spring) over one year. DED was diagnosed according to TFOS DEWS II criteria, and Demodex infestation was assessed by eyelash epilation and quantified using an infestation index. Temperature, relative humidity, PM10, and PM2.5 were obtained from a local meteorological station. Seasonal differences were analyzed using repeated-measures statistical tests. Seventy-seven participants were enrolled, of whom 55 completed all four evaluations. Significant seasonal variation was observed in Demodex infestation prevalence (P = 0.035), infestation index (P < 0.001), DED prevalence (P = 0.043), and OSDI score (P < 0.001). Demodex infestation burden peaked during fall, whereas DED prevalence and symptom severity were highest during spring. Although environmental conditions differed significantly across seasons, no climatic variable was independently associated with either Demodex infestation or DED. Ocular Demodex infestation and DED exhibited distinct seasonal patterns. Seasonal variation was more evident for infestation burden than prevalence, suggesting that quantitative measures provide a more sensitive indicator of seasonal changes in Demodex populations. These findings support a multifactorial influence of seasonal environmental conditions on ocular surface health, rather than effects attributable to individual climatic variables.
