ABSTRACT

The plantain weevil, Mecinus pascuorum (Gyllenhal), an introduced species associated with narrow leaf plantain, has become a regular and common post-harvest contaminant of kiwifruit in South Auckland. Here we describe its life history in New Zealand for the first time, based on surveys of narrow leaf plantain, shelter trees and kiwifruit vines, light trapping and ovarian dissections. Adult plantain weevils were captured in light traps from October to mid-November, and appeared on narrow leaf plantain in early October with numbers peaking in early November before declining in December. Ovarian and oocyte development occurred approximately 3 weeks after adults first appeared on narrow leaf plantain, and eggs were probably laid throughout November. Newly emerged adults were found from late December, and the majority emerged from narrow leaf plantain seed heads in January before dispersing by flight. Adults were subsequently found in crevices in tree and vine bark, coarse shelterbelt litter and foliage from January until mid-September. Adults were also found in the distal end of kiwifruit from late January until at least March. We conclude there is one generation per year with a relatively brief immature stage of 2 months and a long-lived adult stage of about 11 months.

摘要

车前草象鼻虫Mecinus pascuorum (Gyllenhal) ，一种与窄叶车前草相关的引入物种，已成为奥克兰南部奇异果常见的收获后污染物。在这里，我们首次描述了它在新西兰的生活史，基于对窄叶车前草、庇护树和奇异果藤蔓、光捕获和卵巢解剖的调查。10 月至 11 月中旬，成年车前草象鼻虫在光陷阱中捕获，并于 10 月初出现在窄叶车前草上，数量在 11 月初达到峰值，然后在 12 月下降。卵巢和卵母细胞的发育发生在成虫首次出现在窄叶车前草上大约 3 周后，卵可能在整个 11 月产卵。从 12 月下旬开始发现新出现的成虫，大多数在 1 月从窄叶车前草种子头中出现，然后乘飞机散开。随后在 1 月至 9 月中旬在树木和藤蔓树皮、粗糙的防护林枯枝落叶和树叶的缝隙中发现了成虫。从 1 月下旬到至少 3 月，在猕猴桃的末端也发现了成虫。我们得出的结论是，每年有一代具有 2 个月的相对短暂的未成熟阶段和大约 11 个月的长期成年阶段。