INFLUENCE OF ENVIRONMENTAL-FACTORS ON OVIPOSITION AND EGG DEVELOPMENTIN AMBLYOMMA-LIMBATUM AND APONOMMA-HYDROSAURI (ACARI, IXODIDAE)

Influence of environmental factors on oviposition and egg development in Amblyomma limbatum and Aponomma hydrosauri (Acari: Ixodicae). Inter national Journal for Parasitology 24: 83-90. This study examined the i nfluence of temperature and light on the length of the pre-oviposition period of engorged females of two Australian ixodid ticks, Amblyomma limbatum and Aponomma hydrosauri. The hatching success and development time of eggs of both species were also compared at different temperat ures and relative humidities. Darkness was found to have no effect on the duration of the pre-oviposition time or reproductive output of fem ales of either species. In contrast, the preoviposition period of fema les of both species decreased with increasing temperature. Amb. limbat um females had shorter pre-oviposition periods than Ap. hydrosauri at all temperatures examined. Temperature and relative humidity had a mar ked effect on the hatching success of eggs. Eggs of both species had r educed hatching success at low relative humidities. Eggs failed to hat ch at temperatures below 21 degrees C. Ap. hydrosauri eggs also failed to hatch at 34 degrees C while Amb. limbatum eggs failed to hatch at 36 degrees C. Within the range of temperatures suitable for egg develo pment, the hatching times of eggs of both species decreased with incre asing temperature. Amb. limbatum eggs developed faster than Ap. hydros auri eggs at temperatures greater than 25 degrees C, but slower at coo ler temperatures. These differences in the duration of their preovipos ition period, and the responses of females and their eggs to different temperatures and relative humidities correlate with the different cli mates the two species experience throughout most of their distribution al range.