Ecological factors shaping ectoparasite communities on heteromyid rodents at Médanos de Samalayuca

Rodent ectoparasites are vectors for important pathogens of wildlife, domestic animals, and even zoonosis. Nevertheless, distribution patterns of ectoparasites are not fully understood; habitat, season, and host species are important predictors of distribution and prevalence. Heteromyid rodents are considered important reservoirs of diseases, given the presence of different ectoparasites and pathogens in them, and they offer the opportunity to learn about the ecology of parasites. The aim of the present work was to survey ectoparasites associated with heteromyid rodents near a National Protected Area in Chihuahua Mexico, south of the USA-Mexico border, and asses the effects of ecological factors (season, vegetation type, host species, and host body condition) on parasite infestation. We sampled five different locations from January 2018 to July 2022; 845 heteromyid rodents were examined and 49 fleas and 33 ticks were collected. Ectoparasites belonged to the Siphonaptera and Ixodida orders, including three families Ixodidae (Riphicephalus sanguineus), Pulicidae (Pulex irritans), and Ctenophthalmidae (Meringins altipecten, M. dipodomys). Five species of host rodents were captured, Dipodomys merriami, D. ordii, Chaetodipus eremicus, C. hispidus, and C. intermedius, but the last two species did not present any ectoparasites. Dipodomys merriami presented the highest flea and tick prevalence followed by D. ordii. We found parasitic partnerships between heteromyids according to ecological factors. The infestation in C. eremicus was related to body condition, vegetation type, and sex; in D. merriami, it was related to vegetation type and season, while D. ordii did not present a clear pattern of infestation. Our results suggest that the infestation patterns of heteromyid rodents in desert habitats are species dependent.

Acari (Parasitiformes and Acariformes) From Mexico: Analysis of Their Geographical and Host Distribution in Rodentia (Cricetidae)

The study of Acari associated with cricetid rodents in Mexico began at the end of the 1930s. Despite efforts to gathering the information, only listings were built, but none of these studies present an analysis of the available data. A search was made through electronic databases; in addition, some not published records contained at Collection of Laboratorio de Acarología, Facultad de Ciencias, Universidad Nacional Autónoma de México were included in the inventory. Combining the literature records and those deposited in the collection, the total number of species of Acari associated with this family of rodents is 165, distributed in two superorders, four orders, 15 families, and 57 genera. Of the 15 families registered, the richest is Trombiculidae (70 nominal species and 75 taxa), followed by Laelapidae (39 and 42, respectively), Ixodidae (13 nominal and 16 taxa), and Leewenhoekiidae (13 nominal and taxa). From the bibliographic searches, a total of 76 papers were recovered with information on the association between Acari and cricetid rodents in Mexico. The main detected approach in the literature was taxonomic (75 works) and one on detection of pathogens. From the 145 known species of cricetids recorded in Mexico, only 72 (distributed in 18 genera) have been studied and found to host Acari. The use of regionalization of Mexico in provinces allowed us to map the records of Acari associated to cricetids in the most natural approximation of their distribution. We recognize and discuss seven factors that favor the scarcity and asymmetry of acarological studies in Mexico.

Catalogue of the free-living and arthropod-associated Laelapidae Canestrini (Acari: Mesostigmata), with revised generic concepts and a key to genera

The cosmopolitan mite family Laelapidae includes both free-living predatory species and species associated with arthropods, mammals or birds. This work presents a list of free-living and arthropod-associated species of laelapids, with corresponding taxonomic information and references. It includes 1088 species (in addition to three subspecies) assigned to 73 genera, 61 new combinations and two new synonymies at the generic level. Laelaps (Apolaelaps) Silvestri is raised to the generic level. Many of the species described before about 1950 are poorly characterised and cannot be classified with confidence at the family or generic level. Hence, ten genera, one subgenus, 121 species (ca. 70% of which were reported as Hypoaspis Canestrini or Laelaps (Hypoaspis) Canestrini) and one subspecies, are considered incertae sedis, because of their inadequate morphological characterisation in the literature. Some of these may not even belong to the Laelapidae or to the groups of interest for this publication. A total of 89 species, 30 genera, one subgenus, one tribe and one subfamily previously associated with genera treated in this catalogue are now placed in other families or, less commonly, in laelapid genera not considered here because they are considered essentially vertebrate parasites (taxa excluded). Twenty-six other species (one cited as a “variety”) are cited as nomina nuda. An illustrated key to the 73 genera included in the catalogue along with revised generic diagnoses are provided.