First record of Laelaps mazzai (Mesostigmata: Laelapidae) in Peru associated with Calomys sorellus (Cricetidae: Sigmodontinae), an endemic rodent, with insights about its morphological variation

Espinoza-Carniglia M.; Yauris C.; Rengifo E.M.; Lareschi M. · Revista de la Sociedad Entomologica Argentina (2025) · DOI: 10.25085/rsea.840207

Resumen

Laelaps mazzai Fonseca (Mesostigmata: Laelapidae) is a parasitic mite associated with the genus Calomys Waterhouse (Rodentia: Cricetidae) that shows variations on the size of its dorsal shield. Although, there are six species of Calomys in Peru, there are no records of L. mazzai associated to those species and consequently, neither are records about its size variation. We report the first occurrence of L. mazzai in Peru, associated with Calomys sorellus Thomas and its variation in the dorsal shield size. Morphological and molecular analyses were used to identify the mites and explore potential phenotypic variations in this new host-parasite association. While the mites exhibited diagnostic characters consistent with L. mazzai, they displayed larger dorsal shields, longer distance between setae, and fewer setae in the medial podonotal region compared to mites from other Calomys species. However, molecular analysis of the 18S-ITS1-5.8S-ITS2-28S region showed minimal genetic divergence (0–0.2%) between mites from C. sorellus and those from other Calomys species. The observed morphological variations are consistent with previous findings of phenotypic plasticity in L. mazzai, potentially influenced by the host and/or environmental factors. © ESPINOZA-CARNIGLIA et al. 2025.