Butterfly Basking

Butterfly Basking

In order to fly , cold –blooded animals like butterflies must warm their flight muscles to sufficient temperature (ca 25- 30 degree C). For this , butterflies usually bask in the sun with open wings to keep the thoracic muscles warm for the next flight . Butterflies store thermal energy from the sun , warming the surfaces of the wings and the veins through which the haemolymph circulates and then passes to the body tissues . Basking may be dorsal basking when the heat absorption is increased by spreading the wings, angling the exposed surface and making a more direct contact with the substrate which is warmer or lateral basking when the wings are clasped above the bodies and their ventral surface perpendicular to the sun’s rays .

Many Lycaenidae absorb maximum heat by basking with closed wings and at an angle to the sun . The dark pigments on the underside of the wings absorb more radiant energy and warm the flight muscles of the thorax efficiently . White winged butterflies use their white to reflect the sun rays directly to the thorax by holding the wings like ‘V’ (10-60 angle ) . The black areas near the wing bases absorb the heat effectively and efficiently which is then directly transferred to the muscles . When solar radiation falls beneath the levels needed to ensure sufficient heating , especially at dusk or during cloudy days , butterflies immediately seek shelter or a perch . In the tropics , flight activity lasts longer because of the oppressive heat which allows the butterflies to become active before sunrise and to continue after dark.

Migration