LAND SNAIL PREFERENCE OF FIREFLY Pyrocoelia tonkinensis Olivier LARVAE AND THEIR POPULATION DYNAMICS AT THE CHULALONGKORN UNIVERSITY FOREST AND RESEARCH STATION, LAI NAN SUBDISTRICT, WIANG SA DISTRICT, NAN PROVINCE

Abstract

Land snail preference, feeding behavior and population dynamics of firefly Pyrocoelia tonkinensis larvae and land snail prey were investigated from February 2013 to February 2014. The number of attacks of the firefly larvae on Cryptozona siamensis land snails was significantly higher than Sarika resplendens. Feeding behavior of firefly larvae were divided into two phases, namely, searching phase and handling phase. The larval feeding behavior began with head stretch followed by walking, sprinting and approaching, touching, biting, head shake, mandible chew, head insert, cleaning and walking around, respectively. Moreover, firefly larvae significantly spent their time on feeding unit more than the other behavioral units. The firefly larva population size was highest in September 2013. Similarly, C. siamensis land snail population size was highest in July and September 2013. Simple correlation analysis revealed that land snail population had a significant positive correlation on the firefly larva population. Environmental factors such as herbaceous coverage showed significant positive effect on the firefly larva population. Likewise, soil moisture, canopy coverage and herbaceous coverage showed significant positive effects on C. siamensis land snail population. Additionally, flashing displays of adult male P. tonkinensis firefly occurred in eight months. Average numbers of flashing displays were highest in April and May 2013. The flashing displays began at about 19:00 PM. The display numbers peaked from 21:30 PM to 22:00 PM. After peak, flashing displays gradually decreased until the end of flashing activity at about 06:00 AM.