The life cycle and occurrence of Haemaphysalis concinna (Acari: Ixodidae) under field conditions.

Abstract

The life cycle and occurrence of Haemaphysalis concinna were investigated under field conditions from April 2012 to March 2013 in Eerguna National Natural Reserve Area situated on the China-Russia border in Inner Mongolia, China. Under natural conditions, the whole life cycle of H. concinna was allowed to complete in a natural tick habitat. With domestic rabbits supplied as hosts, the seasonal occurrence and behaviors of H. concinna were also observed in the field plot which was chosen in a natural tick habitat from April to October 2012. Results indicated that the durations of the life cycle from unfed adults to the next generation unfed adults of H. concinna ranged from 124 to 186 days (average periods of 153.1 days). The incubation time of eggs ranged from 39 to 57 days (average periods of 41.3 days), which is the longest period among the four developmental stages, followed by the premolt periods for larvae (averaged 37.7 days) and nymphs (averaged 26.0 days). The number of eggs was positively correlated with the weight of engorged females (r=0.8562, p<0.001). Eggs were laid in high amounts in the first week, subsequently, the egg amount declined gradually with small peaks occasionally observed. The female reproductive efficiency index (REI) and reproductive fitness index (RFI) was 6.2 and 4.3, respectively. Observations on the occurrence of H. concinna indicated that, in the confined plot under field conditions, larvae appeared in late May and peaked in early July, and nymphs were active during July and August. Therefore, there was an overlap in the occurrence of larvae and nymphs in both June and July.