A study of distribution of abundance was carried out with the terrestrial amphipod Talitroides topitotum (Burt, 1934) from Serra do Mar, in the municipality of Guaratuba, Paraná State, Brazil. Monthly, collections were made with Malaise nets, from June/1985 to June/1986 at eight sites with varied degree of preservation, all located in a Tropical Rain Forest nearby the Guaricana Hydroeletric Plant. Four sites were located at 270 m of altitude and another four at 720 m high. Each collection period lasted five days. The precipitation rate oscillated from 43.70 mm to 388.30 mm, the air temperature from 9.00ºC to 37.50ºC and the relative humidity of the air from 72.75% to 93.07%. A total of 2191 amphipods were obtained, among which 1626 females with oostegits but without eggs in the marsupium, 558 ovigerous females, six juveniles and an adut without any secundary sexual characters. The capture was selective towards adult amphipod. The number of amphipod oscillated from 19 to 969 in the collection sites, with high frequencies in sites of intermediate degree of preservation. The annual frequency varied from six to 498 individuals. The 270 m high population showed four picks in the abundance curve, while in the 720 m high population only three. Antropological influence favoured high frequencies of amphipods, but in sites of excessive degree, these animals were less numerous. The conjuction between high precipitation and high relative humidity of the air favoured abundance of amphipod populations. On the other hand, they were limited by air temperatures below 13ºC and above 35ºC.
Annual fluctuation; anthropological influences; Malaise trap; terrestrial amphipod
