Biology Reference
In-Depth Information
Related Species
76
Haemaphysalis obesa of Northeast India and Southeast Asia is closely related to H.
hirusta found in Java. These two species are a part of the H. obesa group. The lar-
val and nymphal stages of hirusta and obesa show a close relationship with each
other. In the obesa nymph, the cornua and coxa I spur are approximately one-half
the size of those in hirusta. The larval obesa is more easily separated from the lar-
val hirusta in that its cornua are well developed which is almost obsolete in hirusta
and the ventral spur of palpal segment III is approximately 3 times as long as in
hirusta.
Life History of obesa
89
Life cycle of this species has been studied by Ilkal et al. in 1981 under room tem-
perature (17
26
C and RH 90
95%). Most of the adults released on the host
(cow calf) were found attached within 24 h of their release. They commenced feed-
ing by the third day of their release. Copulating pairs were observed during feeding
period. The engorged females started detaching from the sixth day onward and con-
tinued up to the tenth day. Two well-defined phases were observed at the time of
feeding. The first or the “preparatory phase” started soon after attachment and
lasted until last but one day of parasitic stage. The second phase or the “repletion”
was of a shorter duration and lasted till the detachment of the fully engorged tick.
The weight of the fed females ranged from 236.8 to 575.6 mg. The average amount
of blood ingested by the females was approximately 220 times their unfed body
weight (1.66 mg). The oviposition commenced 4
8 days after detachment from the
host. The process lasted from 15 to 21 days. The number of eggs laid ranged from
3,740 to 5,245. The maximum number of eggs laid was on the third or fourth day
of commencement of oviposition. The average weight of an egg ranged from
0.0479 to 0.0791 mg. The incubation period for hatching of the eggs ranged from
45 to 58 days at 20
C. The eggs hatched in the same sequence as they were laid.
The minimum pre-feeding period for larvae was 2 days, but the optimum number
of fed larvae was recovered when they were released on the host after the 15th day
of hatching. The time taken by the larvae to complete their engorgement ranged
from 2 to 6 days. The largest number of engorged larvae was obtained on the third
day after release. As in the case of females, the larvae also showed two phases
while feeding. The period for the fed larvae to molt into nymphs ranged from 8 to
12 days after completion of engorgement. The nymphs were ready to feed a few
hours after emergence. The feeding period (on chicks) for the nymphs ranged from
3 to 6 days. In feeding nymphs also, two phases, i.e., preparatory phase and reple-
tion phase, were observed without any sharp demarcation. The fed nymphs moved
for 3
14 days for the
nymphs to molt into adults after completion of engorgement phase (
Table 2.10
).
5 days before they entered the molting phase. It took 12
Ecology
76
In India, the species is known from West Bengal, Assam, and Meghalaya.
