Effect of temperature and humidity on egg hatch, moulting and longevity of larvae and nymphs of Dermacentor reticulatus (Ixodidae).
Larvae of Dermacentor reticulatus hatched at a temperature range of 20-34 degrees C, but a high egg hatch success of > 90% was only achieved at 20 degrees C and 27 degrees C and 100% r.h. The developmental capability of the eggs at low or freezing temperatures persisted up to 3 weeks at -10 degrees C and up to 8 weeks at 5 degrees C. The 50% mortality period of unfed larvae and nymphs increased with rising humidity and was longest at 5 degrees C and 100% r.h., amounting to 83.5 days for larvae and 108 days for nymphs. Engorged larvae and nymphs only moulted in the temperature range of 10-27 degrees C. The percent moulting success was low at 10 degrees C and increased with rising ambient humidity at 20 degrees C and 27 degrees C reaching more than 90% at 100% r.h. After incubation at low or freezing temperatures and subsequent transfer to 20 degrees C and 100% r.h. engorged larvae did not moult after exposure to -10 degrees C, but they tolerated 0 degrees C and 5 degrees C up to 3 and 10 weeks, respectively, and developed into nymphs. Engorged nymphs moulted into adults even after preceding incubation at -10 degrees C, their metamorphosis capability persisted for a maximum of 4 and 17 weeks at 0 degrees C and 5 degrees C, respectively.
Zahler
M
M
Institute for Comparative Tropical Medicine and Parasitology, Munich, Germany.
Gothe
R
R
D000818:Animals; D003870:Dermacentor / Q000196:embryology / Q000254:growth & development / Q000502:physiology*; D004625:Embryo, Nonmammalian / Q000502:physiology*; D006813:Humidity; D007814:Larva; D008136:Longevity; D008675:Metamorphosis, Biological; D009758:Nymph; D013696:Temperature