Development and fecundity of captive Harmonia sedecimnotata feeding on Aphis craccivora
Abstract:
[Aim] To determine the biological
characteristics of the ladybird, Harmonia sedecimnotata, feeding on Aphis craccivora under laboratory conditions, in order to provide basic
dates to improve the mass-rearing of this species in captivity. [Methods] A population life table for a captive
population fed using controlled feeding was completed, and the effects of
different temperatures on the growth and development of H. sedecimnotata were measured. In addition, the reproductive characteristics of the population
at (26±1) ℃ are
described. [Results] Although all
ladybirds could complete their life-cycle at temperatures in the range of 15-30
ºC, the development period of each stage shortened with increasing temperature.
There were significant differences in the time required to develop from egg to
adult at 15, 20, 25 and 30 ℃ (P<0.001), which were (42.30±1.21), (31.86±1.46), (18.59±0.89)
and (15.73±0.87) d, respectively. The survival rates of 1st-4th instar
larvae and pupae were highest at 25 ℃ (95.08%±1.76%, 96.18%±1.41%, 98.63%±0.97%, 94.63%±1.64%
and 97.80%±1.81%, respectively) . There were significant differences in the
survival rate of all life stages at 15, 20, 25 and 30 ℃ (P<0.001), which were 20.00%±2.72%, 41.11%±1.57%, 64.76%±2.93%
and 48.89%±1.57%, respectively. The development threshold temperature and
effective accumulated temperature of a generation of H. sedecimnotata were 9.411 ℃ and
300.703 degree·days, respectively. The sex ratio of the experimental population
was 0.51, the oviposition period was (79.56±63.59) d, the number of eggs laid
per female was 1 289.89±724.70. The hatchability was 77.67%±2.49% and the
number of trophic eggs was 10.67%±1.25%. There was a significant, positive
correlation between fecundity and female longevity. The net reproductive rate (R0),
generation time (T), intrinsic rate of increase (rm)
and finite rate of increase (λ), were 633.933, 76.828, 0.084 and 1.088,
respectively. [Conclusion] H.
sedecimnotata can complete its life-cycle and has relatively high
reproductive capacity at temperatures in the range of 15 to 30 ℃. Consequently,
this species should receive more consideration as a potential agent of
biological control.