Flea and mite biodiversity associated with Neotropical sigmodontine rodents: studies in northeastern Argentina and perspectives for the rest of the continent

MARCELA LARESCHI

Mendoza

Conferencia; Symposium: Neotropical mammal parasite biodiversity: advances and perspectives. IMC10, X Internatonal Congress of Mammals; 2009

Most of the studies on fleas and mites ectoparasites of sigmodontine rodents in Argentina took place in Buenos Aires Province. Component communities were studied, taxonomic revisions were carried out, and new geographic and host distributions were recorded. In the last years researches are taking place in northeastern Argentina, an understudied area which comprises Misiones, Corrientes and Entre Ríos Provinces. Herein preliminary results are presented, and comparisons with other areas are commented. More abundant rodents sampled (N=107) were identified as the akondotines Akodon azarae, Akodon montensis, Necromys lasiurus and Thaptomys nigrita, and the the oryzomines Oligoryzomys flavescens and Oligoryzomys nigripes. Ectoparasites were obtained by examining the pelage of the rodents, fixed in 96% ethanol and prepared following conventional techniques for their identification. Prevalence (P) and mean abundance (MA) were calculated. Fleas (Rhopalopsyllidae, Rhopalopsyllinae) (N=4; P= 2.80; MA= 0.04) were collected only from A. montensis and O. nigripes from Misiones, and N. lasiurus from Corrientes, while mites (Laelapidae, Laelapinae) (N=902; P=  ; MA=8.43) from every host and locality. Oligoryzomys species were parasitized by the coocurrence of the mites Gigantolaelaps wolffsohoni, Mysolaelaps spp., Laelaps paulistanensis and Laelaps manguinhosi. Concerning Mysolaelaps species, a replace of parvispinosus by microspinosus was observed in a gradient from north to south. Necromys lasiurus was associated with the mite Androlaelaps rotundus (P= MA= 10.18) in every locality. Every remaining akodontine was parasitized by a different undescribed species of Androlaelaps very close to A. rotundus. Androlaelpas fahrenholzi, a cosmopolitan composite species, was recorded for every host species and locality. Differences in P and MA between high ectoparasitic taxa may be related to environmental conditions. In opposite, in arid areas such as Patagonia and Chaco Seco, higher P and MA were observed in fleas. All host-parasite associations herein recorded are in accordance with preliminary results of ongoing researches along hosts distributions.