Influence of temperature and relative humidity on the moulting success of Amblyomma limbatum and Aponomma hydrosauri (Acari: Ixodidae) larvae and nymphs

• Published in: International journal for parasitology Vol. 30; no. 9; pp. 973 - 979
• Main Authors: Chilton, Neil B, Andrews, Ross H, Bull, C.Michael
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.08.2000; Elsevier Science
• Subjects: Amblyomma limbatum; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Aponomma hydrosauri; Autoecology; Biological and medical sciences; Body Weight; Female; Fundamental and applied biological sciences. Psychology; Humidity; Ixodid ticks; Ixodidae; Larva - physiology; Larvae; Male; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; Molting - physiology; Moulting; Nymph - physiology; Nymphs; Pre-moult period; Protozoa. Invertebrata; Random Allocation; Relative humidity; South Australia; Temperature; Ticks - growth & development; Ticks - physiology; Time Factors; Vectors. Intermediate hosts; South Australia; Relative humidity; Larvae; Pre-moult period; Temperature; Amblyomma limbatum; Moulting; Aponomma hydrosauri; Ixodid ticks; Nymphs; Parasitiformes; Laboratory study; Life history; Interspecific comparison; Body weight; Environmental factor; Duration; Molt; Arachnida; Acari; Larva; Ixodida; Arthropoda; Development; Nymph; Invertebrata; Vector; Ixodidae
• ISSN: 0020-7519; 1879-0135
• DOI: 10.1016/S0020-7519(00)00085-0

This study compared the duration of the moulting periods of engorged larvae and nymphs of the ixodid ticks, Amblyomma limbatum and Aponomma hydrosauri, at different temperature/relative humidity regimes, and examined the relationships between the engorged weight of ticks and their weights after moulting. The results showed that for each species, there was a significant relationship between the weights of unfed nymphs and engorged larvae, and the weights of unfed adults and engorged nymphs. The weight of engorged nymphs was also a good indicator of their sex, with female ticks having heavier weights as engorged nymphs. Temperature and relative humidity had a marked effect on the moulting success of engorged ticks of both species. Aponomma hydrosauri larvae and nymphs were able to moult at lower temperatures than Amb. limbatum but most ticks, except Ap. hydrosauri larvae, failed to moult at 13°C. Additionally, there was a marked decrease in the pre-moult times of ticks at higher temperatures, with larvae taking less time to moult than nymphs. At temperatures greater than 21°C, Amb. limbatum took less time to moult than Ap. hydrosauri but this interspecific difference was less marked for nymphs. The interspecific differences in the responses of engorged larvae and nymphs to different temperatures and relative humidities correlated with interspecific differences in off-host behaviour and with the different climates the two species experience throughout most of their distributional range.