Coconut Black-headed Caterpillar

The female moth lays eggs in small groups on the underside of coconut leaflets near to feeding larvae. The larvae hatch from the eggs after three days on average, and then move into the first of a series of larval instars. Larvae of O. arenosella generally go through five instars, but have been recorded to go through as many as eight instars in laboratory settings. Instars from one to five last 6 days, 7 days, 7 days, 5 days, and 10 days respectively, which makes the larval stage approximately 48 days in length. Larvae are generally less than 4.0 mm in size between instars 1 and 3, between 4.0 and 11.0 mm from instars 4 to 6, and larger than 11.0 mm in instars 7 and 8. Some early larval and egg mortality has been observed in O. arenosella as a result of cannibalism on the eggs and younger larvae by older larvae. Adult coconut black-headed caterpillars rest under the surface of the damaged coconut palm leaves, where most of the damage to the coconut fronds can be observed. Larvae construct galleries of silk and frass, into which they retreat if disturbed. These galleries are also where pupation occurs, which lasts approximately eight days. Little is known about the adult (moth) stage of O. arenosella. …