Table 3. Hatching of Ae. aegypti eggs in brackish and fresh water.

Experiment	Number of eggs out of 150 from different colonies hatching into larvae at 48 h
	Original fresh water colony at 0 ppt salinity	Reversal fresh water colony at 10 ppt salinity	Reversal brackish water colony at 0 ppt salinity	Original brackish water colony at 10 ppt salinity
5th generation Experiment 1	127±8	63±10*	125±9	86±13*
2nd generation Experiment 2	128±4	61±17*	123±11	74±23*e
5th generation Experiment 2	123±7	73±9*	121±8	74±12*

Results are the mean numbers of eggs from three replicate experiments ± standard deviation that hatched into larvae at 48 h from 150 original eggs. Unpaired Student's t tests were performed to determine the significance of differences in the mean numbers of eggs hatching in brackish and fresh water for the corresponding original and reversal colonies (columns 1 vs 2 and 3 vs 4 respectively) in the three different experiments. The asterisks indicate that in every such comparison significantly more eggs hatched in fresh water compared to brackish water at p<0.05. Corresponding comparisons of the pairs of means in columns 1 vs 3 and 2 vs 4 were not statistically significant with p>0.05. The original brackish and fresh water colonies were derived from Ae. aegypti collected in Kurunagar and Thirunelvely respectively in the Jaffna peninsula.