Spurgeon Dale W, Suh Charles P-C, Esquivel Jesus F
Pest Management and Biocontrol Research Unit, USDA, ARS, ALARC, Maricopa, AZ.
Insect Control and Cotton Disease Research Unit, USDA, ARS, College Station, TX.
J Insect Sci. 2018 Sep 1;18(5):1. doi: 10.1093/jisesa/iey084.
Distribution of the boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), in the United States has been greatly reduced by eradication efforts. Still, it remains a key pest of cotton (Gossypium spp., [Malvales: Malvaceae]) in the New World, and has proven difficult to eliminate from Mexico and from southern Texas. In those regions, improved knowledge of boll weevil overwintering ecology may benefit efforts by eradication and management programs. Adult diapause in the boll weevil is well documented, but influences of the feeding period duration between adult eclosion and assessment of diapause remain unstudied. We examined diapause incidence and associated survival for weevils fed for 7, 14, or 21 d after adult eclosion. Diapause incidence of females was less influenced by feeding duration compared with males. For males, highest diapause incidence occurred after 14 d of feeding compared with 7 or 21 d. Host-free survival tended to be higher after 14 d of feeding compared with 7 or 21 d, although many weevils were long-lived (≥80 d) after each feeding period duration. Males exhibited higher survival compared with females, and survival was higher for weevils fed large flower buds (squares) compared with smaller squares. Survival was most influenced by temperature; longevity increased with decreasing temperature except at the lowest temperature (12.8°C). These results suggest an optimal feeding period for induction of diapause and maximized host-free longevity. These findings may permit improved timing of late-season insecticide treatments aimed at reducing overwintering populations, and thereby improve effectiveness of eradication and management programs.
通过根除行动，棉铃象甲（Anthonomus grandis grandis Boheman，鞘翅目：象甲科）在美国的分布范围已大幅缩小。不过，它仍是新大陆棉花（棉属，[锦葵目：锦葵科]）的主要害虫，并且已证实很难从墨西哥和得克萨斯州南部根除。在这些地区，深入了解棉铃象甲的越冬生态学可能有助于根除和管理计划的实施。棉铃象甲成虫滞育现象已有充分记录，但成虫羽化至滞育评估期间取食时长的影响仍未得到研究。我们研究了成虫羽化后取食7、14或21天的象甲的滞育发生率及相关存活率。与雄虫相比，雌虫的滞育发生率受取食时长的影响较小。对于雄虫，取食14天后的滞育发生率最高，而取食7天或21天后的滞育发生率较低。与取食7天或21天相比，取食14天后的无寄主存活期往往更长，尽管每个取食期后许多象甲的寿命都很长（≥80天）。雄虫的存活率高于雌虫，取食大花蕾（棉蕾）的象甲的存活率高于取食较小棉蕾的象甲。存活率受温度影响最大；除最低温度（12.8°C）外，寿命随温度降低而延长。这些结果表明存在一个诱导滞育和使无寄主寿命最大化的最佳取食期。这些发现可能有助于优化旨在减少越冬种群数量的季末杀虫剂处理时间，从而提高根除和管理计划的有效性。
