Effects of temperature and humidity on oviposition, molting, and longevityof Dermanyssus gallinae (Acari : Dermanyssidae)

The juvenile development and survival of Dermanyssus gallinae (De Geer) kep t in vitro at different temperatures and humidity were investigated to obta in biological baseline data for a Swedish population. Individual females, e ggs, larvae, and protonymphs were observed with regard to egg-production, d uration of various stages, and longevity when kept at different temperature s and relative humidities. Female mites laid eggs at temperatures between 5 and 45 degrees C with the highest numbers laid at 20 degrees C and 70% RH, but development to larvae and protonymphs was only observed at temperature s ranging from 20 to 25 degrees C. The average duration of oviposition vari ed from 1.0 to 3.2 d within the temperature range 20 - 45 degrees C but was gradually increased to 28 d at 5 degrees C. Specimens survived for up to 9 mo without access to food when kept in the temperature range of 5-25 degre es C. Temperatures >45 degrees C and at -20 degrees C were found to be leth al. Longevity was similar for females and protonymphs kept at 30 and 45% RH , but it was enhanced at 70 and 90% RH for protonymphs. This study showed t hat D. gallinae can survive for a long time without feeding if the microcli mate is suitable, but it does not thrive at low relative humidities and at temperature extremes. This indicates that changing of the abiotic condition s in infested poultry houses could be a possible measure to reduce mite pop ulations.