A note on seasonal migratory movement of Catopsilia pomona in the plains of Madurai district, Tamil Nadu
2021
Gokul, T. | Ramesh, T.
Migration of Pierid butterfly, common emigrant, Catopsilia pomona was recorded in the plains of Madurai, Tamil Nadu from north-east to south-west (~213 to 223°). The migratory swarm was counted within the imaginary strip of about 10 m wide between 09.30 and 02.00 hr (IST), the total of 5,673 migratory individual of C. pomona were observed in the present investigation. Interestingly swarm individuals are unequal body size and the sex ratio of migrants of C. pomana is about 36.3% male and 63.7% female in the present exploration, it is clearly indicated that the sex ratio is biased towards female. Furthermore the migratory and non-migratory population were compared and estimated through morphometric analysis, it showed that as the thorax mass is higher than the abdominal mass of migratory individuals, and especially the abdominal mass is greater for female. Similarly the length of fore wing (FW) is more than hind wing (HW) whereas the HW breadth is more than breath of the FW of migrants. In addition, the dial variation of swarm density is reached maximum on mid-day hours (11.00 and 12.00 hr) in correspondence with the optimum temperature. The migration activity is strongly correlated with air temperature and moderately with rainfall, humidity, wind movement and wind speed.
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