Abstract:
Calotropis gigantea is a native plant to Sri Lanka having an
ayurvedic medicinal value. People use the plant to gain fodder, fiber,
and fertilizer. Despite its benefits, the plant is considered as an invasive
species in Australia, the USA, etc. As the plant is medicinally,
agriculturally, and ecologically valuable, the study was designed to
investigate phytophagous insects of C. gigantea and their temporal
variation. The field visits were conducted fortnightly from August 2015
to August 2016 in eleven sites in Southern Province (SP). During
sampling, the number of insect species, their abundance, and the
number of Calotropis fruits were recorded in selected trees. Twenty nine insect species were recorded from C. gigantea and among them
twelve species were phytophagous. Dacus persicus and Paramecops
farinosa were destructive phytophagous insects. D. persicus was
recorded in all three districts of SP throughout the year and the mean
abundance varies significantly (p= 0.002) among districts. P. farinosa
was only recorded from Hambantota district. Sphaeroderma sp. was the
most abundant phytophagous insect and varied widely across (p =
0.000) districts of Southern Province. Danaus chrysippus larva was
observed in all selected sites of SP. None of the insect abundance
correlated with Calotropis fruit density, month of year and monthly
rainfall.
