Laboratory observations on Toxorhynchites splendens Wiedemann in Thailand.

ABSTRACT

The biology of Toxorhynchites splendens predaceous larvae which breed in domestic containers like Aedes aegypti was studied. Egg stage lasts 52.64 +/- 0.13 hours. There are four larval instars lasting 2.38 +/- 0.04, 1.24 +/- 0.26, 8.09 +/- 1.6 and 28.78 +/- 5.39 days respectively. Pupal development lasts 5.18 +/- 1.06 days. The adult life span is 29.55 +/- 8.06 days. Growth increment was by measuring the size of head capsule. Number of second instar prey larvae consumed by 1 to 4 instars predaceous larvae were 9.32 +/- 1.77, 5.94 +/- 1.11, 37.03 +/- 7.05 and 273.06 +/- 50.69 respectively. The fourth instar was very aggressive especially 2-3 days before pupation when it killed without eating them. The construction of biological life table indicated net reproductive of increase (R0) of 16.3, capacity for increase (rc) of 0.094, finite rate of increase (lambda) of 1.08 and mean duration of a generation (Tc) of 44.445 days. The mortality at the first and second larval instar was high and the calculated population index (I) was 14.81.