Blossey Bernd
International Institute of Biological Control, European Station, 1, Chemin des Grillons, CH-2800, Delémont, Switzerland.
Oecologia. 1993 Jun;94(3):380-387. doi: 10.1007/BF00317113.
The life history of the root-boring weevil Hylobius transversovittatus was studied in north and central Europe. The weevil develops on Lythrum salicaria, a perennial marshland plant that has become a problem weed in North America. It was found in all habitats of its host plant with the exception of permanently flooded sites. It also attacked L. salicaria in an early successional stage, devastating large parts of the storage tissue. The beetle was found in two-thirds of the field populations examined with a mean attack rate of 76.3%. Larvae developed according to a 1- or 2-year generation cycle depending on the time of oviposition. Adult beetles developing within 1 year emerged between July and October, whereas beetles with a 2-year larval period emerged within 3 weeks in July and August. Adults were long-lived and could hibernate several times. Beetles of the new generation mated right on the spot and some oviposited prior to overwintering. Hibernated females had an oviposition period from May to early September and produced 3-4 eggs/day during the peak oviposition period. Specific mortality factors were scarce. Dispersal flights ensure the regular occurrence of H. transversovittatus in scattered L. salicaria populations. The severe impact of the weevil is expected to reduce the competitive ability of its host plant after introduction into North America.
在北欧和中欧对食根象甲Hylobius transversovittatus的生活史进行了研究。这种象甲以千屈菜为食，千屈菜是一种多年生沼泽植物，在北美已成为一种有害杂草。在其寄主植物的所有栖息地都发现了它，但永久性水淹的地方除外。它还在演替早期阶段侵袭千屈菜，破坏了大部分储存组织。在所检查的三分之二的田间种群中发现了这种甲虫，平均侵袭率为76.3%。幼虫根据产卵时间按照1年或2年的世代周期发育。在1年内发育成熟的成虫在7月至10月间出现，而幼虫期为2年的甲虫在7月和8月的3周内出现。成虫寿命很长，能够多次冬眠。新一代的甲虫就在原地交配，一些在越冬前产卵。冬眠后的雌虫产卵期从5月至9月初，在产卵高峰期每天产3 - 4枚卵。特定的死亡因素很少见。扩散飞行确保了H. transversovittatus在分散的千屈菜种群中经常出现。预计这种象甲引入北美后，其严重影响将降低其寄主植物的竞争能力。
