Ecologia de Phthiraptera, Siphonaptera e Acari (Ixodidae) de pequenos roedores e marsupiais do Parque Estadual da Pedra Branca, Rio de Janeiro, Brasil

Abstract

From October 2005 to October 2007, rodents and marsupials were captured at Pedra Branca State Park, Rio de Janeiro, RJ. This research aimed to characterize the vegetation concerning the study area; to check the existence of a correlation between mesoclimate and microclimate in relation to the presence of parasites and hosts; to identify the dynamics of the hosts and parasites population throughout the seasons and verify the stratification of the small rodents and marsupials fauna as well as the ectoparasitarian fauna. Six spaces of capture were highlighted, in different levels of height. Three types of traps were used, Sherman, Tomahowk and Francesinha, with different baits distributed in five transects. A hundred and sixty mammals were captured, 96 specimens of marsupials and 64 of rodents from the following species: Akodon cursor, Oligoryzomys nigripes, Rattus norvergicus, Rattus rattus, Guerlinguetus ingrami, Sphigurus villosus, Didelphis aurita, Marmosops incanus, Micoureus paraguayanus, Metachirus nudicaudatus, Monodelphis americana and Philander frenatus. It was possible to observe that in hotter (July and August) and drier (December, January and February) months, the number of animals captured is much lower. The vegetation present in the collection areas (in the six levels researched) is composed by secondary vegetation in different stages of regeneration. The areas placed in levels 150, 200, 300 and 400 m can be classified as areas at initial and medium stage of regeneration, while, the areas situated in levels 500 and 600 m the classification is of areas at medium to advanced stage of regeneration. The correlation between the environment (relative humidity, temperature and pluviometric index) and the ectoparasites was only significant to the ticks, showing that, the higher the temperature, the higher is the number of ticks. The dominant species is D. aurita (35%). Three hundred and seventy specimens of ectoparasites were collected: 162 fleas, 105 ticks and 103 lice. The parasites found were: Siphonaptera: Adoratopsylla (Adoratopsylla) antiquorum ronnai, Adoratopsylla (Tritopsylla) intermedia intermedia, Polygenis (Polygenis) occidentalis occidentalis, Polygenis (Polygenis) rimatus, Polygenis (Polygenis) steganus, Polygenis (Neopolygenis) atopus, Ctenocephalidae felis felis, Acari (Ixodidae): Amblyomma geayi, Amblyomma longirostre, Amblyomma scutatum, Amblyomma spp., Ixodes amarali, Ixodes auritulus, Ixodes didelphidis, Ixodes loricatus, Ixodes luciae, Ixodes spp., Phthiraptera: Poliplax spinulosa, Hoplopleura sciuricola, Eutrichophilus minor and Eutrichophilus cercolabes. The siphonapterus obtained the highest prevalence coefficient (28,13%) and the highest abundance index (1,01 flea/host). The phthirapters presented the highest mean intensity of parasitism (17,17 lice/host). The correlation between the numbers of rodents captured and the levels was not significant (rs = 0,23, p = 0,6) and for the marsupials the correlation was negative and also not significant (rs = -0,6, p = 0,2). Polygenis (P.) occidentalis occidentalis was found at the highest frequency (20,8%) among the rodents and in relation to the marsupials, Adoratopsylla (T.) intermedia intermedia was the most frequent (77,7%). E. cercolabes presented the highest frequency (91,5%) among lice; among ticks the highest frequency was of Ixodes loricatus.