Schebeck Martin, Dobart Nina, Ragland Gregory J, Schopf Axel, Stauffer Christian
Department of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna, BOKU, Vienna, Austria.
Department of Integrative Biology, University of Colorado-Denver, Denver, CO USA.
J Pest Sci (2004). 2022;95(2):889-899. doi: 10.1007/s10340-021-01416-w. Epub 2021 Aug 5.
The bark beetle is the most destructive insect pest in Norway spruce-dominated forests. Its potential to establish multiple generations per year (multivoltinism) is one major trait that makes this beetle a severe pest. enters diapause to adjust its life cycle to seasonally changing environments. Diapause is characterized by developmental and reproductive arrest; it prolongs generation time and thus affects voltinism. In a facultative, photoperiod-regulated diapause in the adult stage has been described. In addition, the presence of an obligate, photoperiod-independent, diapause has been hypothesized. The diapause phenotype has important implications for voltinism, as populations with obligate diapausing individuals would be univoltine. To test for the presence of different diapause phenotypes, we exposed Central and Northern European individuals to a set of photoperiodic treatments. We used two ovarian traits (egg number and vitellarium size) that are associated with gonad development, to infer reproductive arrest and thus diapause. We found a distinct effect of photoperiod on ovarian development, with variable responses in Central and Northern European beetles. We observed obligate diapausing (independent of photoperiod) individuals in Northern Europe, and both facultative (photoperiod-regulated) as well as obligate diapausing individuals in Central Europe. Our results show within-species variation for diapause induction, an adaptation to match life cycles with seasonally fluctuating environmental conditions. As the diapause phenotype affects the potential number of generations per season, our data are the basis for assessing the risk of outbreaks of this destructive bark beetle.
The online version contains supplementary material available at 10.1007/s10340-021-01416-w.
树皮甲虫是挪威云杉为主的森林中最具破坏性的害虫。它每年能够繁殖多代（多化性）的潜力是使其成为严重害虫的一个主要特征。树皮甲虫进入滞育状态以使其生命周期适应季节性变化的环境。滞育的特征是发育和繁殖停滞；它延长了世代时间，从而影响化性。在[具体物种]中，已经描述了成虫阶段的兼性光周期调节滞育。此外，还假设存在一种专性的、与光周期无关的滞育。滞育表型对化性具有重要影响，因为含有专性滞育个体的种群将是一化性的。为了测试不同滞育表型的存在，我们将中欧和北欧的个体暴露于一组光周期处理中。我们使用了两个与性腺发育相关的卵巢特征（卵数和卵巢大小）来推断繁殖停滞，进而推断滞育。我们发现光周期对卵巢发育有明显影响，中欧和北欧的甲虫有不同的反应。我们在北欧观察到专性滞育（与光周期无关）的个体，在中欧观察到兼性（光周期调节）以及专性滞育的个体。我们的结果表明滞育诱导存在种内变异，这是一种使生命周期与季节性波动的环境条件相匹配的适应。由于滞育表型影响每个季节的潜在世代数，我们的数据是评估这种破坏性树皮甲虫爆发风险的基础。
在线版本包含可在10.1007/s10340 - 021 - 01416 - w获取的补充材料。
