SHELTER-BUILDING BEHAVIOR OF Erionota torus Evans (Lepidoptera: Hesperiidae) CATERPILLARS FEEDING ON BANANA LEAVES

Shelter construction by different larval instars of Erionota torus Evans (Lepidoptera: Hesperiidae) is most crucial for ensuring proper nutrition, improving microclimatic conditions needed for the normal larval development, and for avoiding the attack of predators and parasitoids. The present study focus on detailed description of the life cycle and shelter building mechanism of different larval instars of banana skipper Erionota torus, a rapidly invading foliophagus insect pest in the banana plantations of Malabar region of Kerala. With detailed observations carried out both in the field and on the laboratory populations of Erionota larvae, we illustrate the types of shelters constructed during the larval ontogeny and also all the activities performed during the process of shelter-building. Further the paper evaluates the factors as well as threats that influence the shelter making behavior .The location of shelters on the host plant and various aspects of larval feeding behavior are also descried. First and second instar larvae of E. torus build and inhabit in their own shelters by successively abandoning the shelters and constructing new ones. The fourth and fifth instars larvae use the shelter made by the third instars. However the leaf area used to construct the shelter of successive instars increases as the larva increases in size. The larvae of E. torus produce shelters in two distinct styles which change as the larvae grow. These changes in the style of shelter building are likely to be correlated with larval size, needs, biotic and abiotic factors. The average area of leaf used to construct the shelters of first, second, third, fourth and fifth instar larvae were 3.62 ± 0.78 cm2, 17.3 ± 0.61 cm2, 102 ± 0.81cm2, 162.8 ± 1.34 cm2, 275 ±1.41 cm2 respectively .Average area of leaf consumed by first, second, third, fourth and fifth instars were 0.67 ± 0.07 cm2, 5.78 ± 0.15 cm2, 27.93 ± 1.37 cm2, 104 ± 0.51 cm2 and 114.2 ± 0.081 cm2 respectively.Averge length of the leaf shelter of first, second, third, fourth and fifth instars were 1 ± 0.22 cm, 4.64 ± 0.61cm ,13 ± 075 cm, 15 ± 1 cm, 15 ± 3 cm respectively.