|Keywords (Extracted from title, table of contents and abstract of thesis)
microcerotermes championi snyder, populus curamericana, azadirachta indica, cedrus deodara, pinus roxburghii, morus alba, tectona grandis, mangifera indica, acacia arabica, thuja occidentalis, abies pindrow, m. championi, p. roxburghii
A detailed study on developmental pathways, feeding preferences, responses to insecticides and swarming behaviour of Microcerotermes championi Snyder is documented under chapters I, II,III and IV.
DEVELOPMENTAL PATHWAYS Developmental pathways of M. championi based on the collection brought from the field were studied. As the soldier caste in the nest population is very poorly represented, it was almost a quagmire to find out the larval stage from which the soldier caste develops. Detailed studies on caste differentiation of the field colony or M. championi revealed that soldiers develop from first instar large worker, which after two moults changes into the soldier. Sexual dimorphism is present in workers. Females are larger than males. Large worker is preceded by two larval instars (first instar larva and second instar large larva) followed by four Successive moults, to become a large mature worker. On the other hand. small worker is also preceded by two larval stages (first instar larva and second instar small larva) followed by three successive moults to transform into a mature small worker. The alate originates from first instar larva and passes through five nymphal instars (defined as such by the presence of wing buds) to become an alate This "imaginal line" is morphologically individualized at the moult of the first instar (undifferentiated) larva. In other words, the separation of the "imaginal line" and the "neuter line" is morphologically visible at the moult of the first instar larva (presence or absence of wing buds). Sexual dimorphism is present in alates.
FEEDING PREFERENCES Ten species of wood were tested for their natural resistance and to reveal feeding preferences of M. championi. In "No choice" laboratory experiments, Abies pindrow was found, highly resistant and Populus euramericana highly palatable. The impact of drying temperature (60°C, 70°C, 80°C, 90°C and 100°C) was studied. The amount of wood consumed in general, increased with increase 'in drying temperature indicating that heat contributed to the loss of natural resistance components of the woods.
When M. championi was given a choice and the woods were offered in combination of two, this termite species repeated its instinct, easily identified the more preferred wood and consumed more of it. Consequently, M. championi showed maximum feeding on P. euramericana and the minimum on A. pindrow and the mean feeding propensity was significantly different (P Azadirachta indica >Cedrus deodara >Pinus roxburghii> Morus alba >Tectona grandis>Mangifera Indica> Acacia Arabica> Thuja occidentalis > Abies pindrow. Although M.. championi fed aggressively on P. Roxburghii, the wooden blocks had undesirable effect on the survival of the species, manifesting toxic nature of the wood.
RESPONSES TO VARIOUS INSECTICEDES Toxicity of Cypermethrin, Biflex, Termidor and Nimbokil against M. championi was compared.. Termidor was more toxic than other insecticides, followed by Cypermethrin. The LC50 values for M. championi exposed to soil treated with Termidor, Cypermethrin, Biflex and Nimbokil were, 1.54,2.691,5.24 and 1584.5 ppm, respectively. Nimbokil was not at all effective against this termite.
Keeping in view tunneling experiments on termites by Jones (1988), a modified test apparatus was designed to measure termite penetration into termiticide treated soil. Even 3000 ppm of Nimbokil treated soil could not resist penetration of termites. Cumulative tunneling distance by M. championi in 25 ppm treated soil of Termidor, Biflex and Cypermethrin was 8.40 mm, 3.42 mm and 8.14 mm, respectively. No penetration was noticed in soil treated with 100 ppm of Termidor, 50 ppm of Biflex and 100 ppm of Cypermethrin. After 7 days termite survival in 25 ppm treated soil of Termidor, Biflex and Cypermethrin was 41.8%, 34.1 % and 21.7%1, respectively. These pesticides should, therefore, be further investigated under field conditions as a candidate for control of pest termites in Pakistan.
SWARMING BEHAVIOUR Swarming behaviour of M. championi was observed during the swarming season of 1997 and 1998. Swarming took place on 16 nights out of the 92 nights for which observations were made. Swarming started after second rainfall of the season, which created suitable combination of relative humidity and temperature required for swarming. Peak emergence of alate was observed after heavy rainfall (44.0 mm) of short duration at 22.I°C to 36.5°C with 80% to 84% relative humidity. Frequency of swarming was maximum between 8.00 pm to 8.30 pm. Overall sex ratio of M. championi indicates that females predominate over males 3:I (F:M).