Hyblaea puera in Kerala. Here we can partially see the black and orange-yellow hind wings under the grayish-brown fore-wings.
English: Hyblaea puera, commonly known as the Teak Defoliator, is a moth native to Southeast Asia. The species has also been recently reported to be present in Central America and Africa. The caterpillar feeds on teak and other species of trees common in the region. The adult moths are comparatively small, with a wing span of 3 – 4 cm, and have a characteristic resting posture that conceals the black and orange-yellow hind wings under the grayish-brown fore-wings. Males and females emerge more or less simultaneously and mating takes place within a couple of days. Eggs are laid on tender new leaves, placed singly near the veins, and usually on the undersurface. They are oval, flat, and white and measure about 1 mm in length. About 500 eggs are laid per female with a recorded maximum of 1000. Larvae hatch in about 2 days. There are five larval instars. The first and second instars mainly feed on the leaf surface. Starting with the third instar, the larva cuts out a leaf flap, usually at the edge of the leaf, folds it over, fastens it with silk, and feeds from within. The entire leaf, excluding the major veins of tender leaves, is eaten, but more veins are left in older leaves. Under the optimal conditions, the larval period lasts 10–12 days. The full grown larva measures about 3.5 – 4.5 cm, and there is considerable color variation in the fourth and fifth instars; the body may be either wholly black or dark grayish to black, with longitudinal colored bands may include a dorsal orange or ocherous band and lateral white lines. A recent study revealed revealed the existence of density-dependent colour polyphenism and resistance build-up against invading baculovirus by H. puera larvae. The mature larvae descend to the ground on silken threads and pupate under a thin layer of leaf litter or soil, within loosely built cocoons made of dry or decayed leaves, or soil particles held together with silk. Pupation may some times occur within green leaves of other plants in the under growth, folded or juxtaposed with silk. On Avicennia plants the caterpillars pupate inside the cases made out of the host plant leaves itself. It is probably an adaptive trait acquired by the species for surviving in the hostile mangrove environment, since the pupation is not possible in the muddy and inundated soils of mangroves. The average pupal period lasts six to eight days under optimal conditions. There is no evidence of hibernation or aestivation of pupa. The teak defoliator is present the year round in teak plantations, but in varying population densities. During the period of natural defoliation of teak (November, December, January), the pest density is very low (endemic). Every year high intensity outbreaks of teak defoliator occurs immediately after the pre monsoon showers in late February or early march in Kerala. These centers are highly localized outbreaks which represents the transitional stage between very sparse endemic population and high density outbreak population. These centers will be 5,000 to 15,000 square metres in area and are characterized by heavy tree top infestation. The months of April, may, June and July witness a series of large outbreaks. During late July or September, the population declines to the endemic level. In some years, there will be fresh outbreaks during the month of October. From then on until the next year, the population remains at the endemic level.