Aspectos da biologia e morfologia da broca do pedúnculo floral do coqueiro, Homalinotus coriaceus (Gyllenhal) (Coleoptera: Curculionidae)

Abstract

The black coconut bunch weevil, Homalinotus coriaceus (Gyllenhal), is an important coconut pest in Brazil, making the flowers and the immature fruits to fall down. Its biology is not well known and therefore efficient pest management in the field is difficult to obtain. Several biological aspects were evaluated in Aracaju - SE at CPATC (Laboratório de Entomologia at Embrapa Tabuleiros Costeiros), under 25 ± 2°C temperature, 70% RH and 12h photophase. Adults were collected in the field and fed on sugar cane pieces, where females laid their eggs individually. Incubation period was from six to 14 days. The larvae were reared in coconut mesocarp and their development lasted about 144 days, with five to seven instars. Pupal period was about 31 days and adult longevity reached 303 to 695 days for females and 246 to 635 days for males. The period from egg to adult was about 181,9 days for females and 188,5 for males. Morphological differences were observed on pupae and adults that can be used for sex determination. The females show two round and elevated structures in the ventral end of the abdomen during the pupal phase. In the adult phase, the abdomen tergite before the last covers the last one.