ABSTRACT

Reproductive biology, abundance and control potential of Paramecops farinosus Wiedemann, (Aak weevil) a prospective biological control agent for Calotropis procera (Aiton) W.T. Aiton, (Calotrope) were studied under field conditions in Lahore, Pakistan, from spring to winter season. Newly emerged adult pairs were introduced inside insect-proof pouches with calotrope fruits, and the life cycle and reproductive biology of P. farinosus were studied. Pre-oviposition period was 4.8 ± 0.17 days and there were 6.1 ± 0.09 eggs per clutch. A female, laid eggs about 5.4 ± 0.32 times, producing 24 offspring during its lifespan. The mortality from egg to adult was 27% and the progeny sex ratio was 3:2 (female to male ratio). The developmental period of P. farinosus (egg to adult) was 59.9 ± 0.82 days and at least two generations were produced per year. The longevity of males and females recorded was 97 ± 1.98 and 69 ± 1.41 days, respectively and the pupae overwinter inside the infested fruits. The number of eggs and larvae inside fruits increased from March to July and declined in subsequent months. The highest number of eggs and larvae per fruit were recorded in July i.e. 8.27 ± 0.65 and 6.31 ± 1.77, respectively. The developing larvae destroyed 100% seeds and internal tissue of infested fruit pods of C. procera, resulting in significant reductions in fruit size (−12%) and biomass (−26%) compared to un-infested (healthy) fruits. The high reproductive capacity and control potential of P. farinosus indicate that this insect holds promise as a biological control agent of C. procera in its invaded ranges, including Australia, the Pacific, and South America.

摘要

Paramecops farinosus Wiedemann (Aak weevil) 的繁殖生物学、丰度和控制潜力是Calotropis procera (Aiton) WT Aiton (Calotrope)的预期生物控制剂，在巴基斯坦拉合尔的田间条件下从春季到冬季进行了研究。新出现的成人对用calotrope水果防虫袋里面引入的，生命周期和生殖生物学P.青霉进行了研究。预产卵期为 4.8 ± 0.17 天，每窝产卵 6.1 ± 0.09 个。一只雌性，在其一生中产卵约 5.4 ± 0.32 次，产生 24 个后代。从卵到成虫的死亡率为 27%，后代性别比为 3:2（雌雄比）。发展期P. farinosus（从卵到成虫）为 59.9 ± 0.82 天，每年至少产生两代。记录的雄性和雌性寿命分别为 97±1.98 和 69±1.41 天，蛹在受侵染的果实内越冬。果实内的卵和幼虫数量从 3 月到 7 月有所增加，随后数月有所下降。每个果实的卵和幼虫的最高数量记录在 7 月，即分别为 8.27 ± 0.65 和 6.31 ± 1.77。发育中的幼虫破坏了C. procera受感染果荚的 100% 种子和内部组织，导致果实大小 (-12%) 和生物量 (-26%) 与未感染（健康）果实相比显着减少。P. farinosus的高繁殖能力和控制潜力表明这种昆虫有望作为C. procera在其入侵范围内的生物控制剂，包括澳大利亚、太平洋和南美洲。