Reproductive Potential, Feeding and Oviposition Preferences of the Mango Pulp Weevil, Sternochetus frigidus (Fabr.) (Coleoptera: Curculionidae), on ‘Carabao’ Mango

Abstract

The longevity and reproductive potential of the mango pulp weevil, Sternochetus frigidus (Fabr.), and the levels of feeding and oviposition for weevils at different stages of mango fruit development were determined to identify suitable stages to use in succeeding experiments. Males lived an average of 496.7 + 32.5 d and females 491.5 + 33.0 d. The oviposition period was 165.1 + 22.1 d comprising 33.6% of the adult life span. The female laid 796.3 + 126.8 eggs in its lifetime at a rate of 5.5 + 0.7 eggs per day. Percentage egg hatch was 90.3 + 1.0 %. Female adult survival was 50% at 73 wk after adult emergence. Weekly fecundity rate (mx) was based on the number of female progeny produced by a female parent. It was at its peak 6 wk after adult emergence, with an average of 26.2 eggs. The estimated value of the net reproductive rate (Ro) was 354.0. Female adults lived up to 70.9 + 15.2 d without mango fruit but on wet bark alone. They lived up to 16.4 + 1.4 d without bark or food and water. Female weevils had a higher level of feeding at 11–42 d after flower induction (DAFI) (panicle elongation to mungbean size fruit stage). Female weevils preferred to oviposit on mango fruits at the fruit enlargement stage (61–90 DAFI). The mango fruit part, whether the top (base of fruit), mid-portion or the bottom (fruit apex), were found to have no influence on the number of eggs laid.