How do insects enter and live inside mangoes?

Adult females (about 6 mm long) of the mango nut weevil Sternochetus mangiferae Fabr puncture the tender fruits just under the rind and lay about 12-30 eggs singly. These punctures leave black or brown marks on the skin.

            A gum-like secretion oozes out of the punctures and cover the eggs. These punctures heal in due course as a result of which the ripe fruits appear unaffected. However, the black marks can be seen sometimes even on ripe fruits.

            Legless fleshy larvae emerge out of the eggs after a week. They tunnel through the developing un-ripened pulp and enter the tender nut which is soft. The nut hardens later as the fruit matures. The larvae thrive on the cotyledons of the nut. They pupate there after three weeks and dark brown adults emerge. Their life cycle lasts for 35-50 days.

            The adult weevil rarely comes out of the ripened fruit. Their attack increases the number of fallen fruits. They hibernate in the crevices and bark till the next fruiting season. The weevil uses the oxygen present in the fruit for respiration.

            The beetle generally attacks soft-pulped varieties such as neelam, mulgoa, banglora, Romani, jehangir, surangudi and padhiri.