The effect of humidity on the oviposition and larval mortality of Haemaphysalis leporispalustris (Packard, 1869) (Acari: Ixodidae) under laboratory conditions.
Oviposition, reproductive and nutritional efficiency indices (REI and NEI), eclosion and larvae mortality of Haemaphysalis leporispalustris were studied under controlled conditions, inside desiccators, at constant temperatures of 25+/-1 degrees C and relative humidity (RH) levels adjusted at 30, 50, 70 and 95%. Fourth generation tick specimens, originated from a colony fed on rabbits (Oryctolagus cuniculus), were used. The experiment was conducted between Jul/1999 and Jan/2001. The pre-oviposition and oviposition periods decreased and increased, respectively, according to the increase in RH. The egg mass weight, REI and NEI, increased according to the increase in RH. The females' residual weight, under high humidity levels, was probably small due to a better energetic use for egg production (51.77 +/- 11.06 mg at 95% RH). The incubation period was inversely proportional to RH increase (45.10+/- 2.47 days; 40.33+/- 1.45 days and 36.85+/- 0.37 days at 50% 70% and 95% RH, respectively). There was no eclosion at 30% RH. Period and percentage of eclosion were directly proportional to the increase of the other RH levels. A diminished formation of embryonic points as well as the desiccation of the already formed eggs were observed. Larval longevity was negatively influenced by 50% RH, with death occurring concomitant to eclosion.
Cardoso
Ana Cristina B
AC
Departamento de Parasitologia Animal, Instituto de Veterinária da Universidade Federal Rural do Rio de Janeiro, Km 7 da BR 465, Seropédica, RJ, Brazil 23890000.
de Freitas
Luciana Helena T
LH
Daemon
Erik
E
Faccini
João Luiz H
JL
D000818:Animals; D006813:Humidity; D026863:Ixodidae / Q000033:anatomy & histology*; D007753:Laboratories; D007814:Larva; D010058:Oviposition