Evaluación morfológica, morfométrica, ecológica y distribución de los ácaros del género Gigantolaelaps presentes en Chile, ectoparásitos del ratón colilargo (Oligoryzomys longicaudatus).

Abstract

The Gigantolaelaps (Mesostigmata: Laelapidae) are easily recognized by their large size. In Chile, Gigantolaelaps wolffsohni is the only recognized member of the genus Gigantolaelaps and it has been reported from four localities in association with Oligoryzomys longicaudatus. No more data are available for this species in this country. Our research study aimed to contribute to the severely limited information about the ecology (prevalence, abundance, median and mean intensity, crowding mean, and aggregation indexes) and distribution of G. wolffsohni in Chile and determine whether factors such as season, ecological region and weight-and sex of the host influence the abundance of this mite. We captured and assessed 329 O. longicaudatus in different seasons and localities (71°23’W – 30°23’S to 70°55’W – 53°09’S). We classified sampled localities as being part of the Mediterranean, Template Forest, or Magellanic Forest ecoregion due to reported genetic and morphological differences of O. longicaudatus between ecoregions. Information about the season, ecoregion, and weight and sex of the host were recorded during mite sampling. These variables were assessed to determine their influence on mite abundance and prevalence through negative binomial and logistic regression models. We found 19 new localities where G. wolffsohni is distributed in Chile. These mites displayed an aggregated distribution in all ecoregions. We found that ecoregion, weight, and sex of the host are not related to the abundance and prevalence of G. wolffsohni. Nonetheless, we found a strong association between the season and the abundance and 6 prevalence of mites. All mites founded were female, additionally we found larvae stage inside some female mites. We discussed the relationship between different ecological aspects and the abundance and prevalence of ectoparasites. Also, we discussed the finding of the larvae of G. wolffsohni, which means that this specie is at least, larviparous, and finally, we discuss the specificity of Laelapidae mites.