Department of Entomology, 219 Hodson Hall 1980 Folwell Avenue, University of Minnesota, St Paul, Minnesota, 55108, USA.
J Insect Sci. 2007;7:1-12. doi: 10.1673/031.007.1001.
The multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), has become a popular study organism due to its promise as a biological control agent and its potential adverse, non-target impacts. Behavioral and ecological research on H. axyridis, including examinations of its impacts, could benefit from non-destructive or non-disruptive sexing techniques for this coccinellid. External morphological characters were evaluated for H. axyridis (succinea color form) sex determination in laboratory and field studies. The shape of the distal margin of the fifth visible abdominal sternite accurately predicted H. axyridis sex for all beetles examined. Males consistently had a concave distal margin, while females had a convex distal margin. In addition, pigmentation of the labrum and prosternum were both significantly associated with H. axyridis sex; males had light pigmentation and females had dark pigmentation. Labrum and prosternum pigmentation increased from light to dark with decreasing rearing temperature and increasing time after adult eclosion for females. Male pigmentation was only affected by a decrease in rearing temperature. Validation through in-field collections indicated that these predictors were accurate. However, labrum pigmentation is a more desirable character to use to determine sex, because it is more accurate and easily accessible. Therefore, we recommend using labrum pigmentation for in-field sex determination of H. axyridis. Implications of this diagnostic technique for applied and basic research on this natural enemy are discussed.
多色亚洲瓢虫，Harmonia axyridis（Pallas）（鞘翅目：瓢虫科），由于其作为生物防治剂的潜力及其对非目标生物的潜在不利影响，已成为一种受欢迎的研究生物。对 H. axyridis 的行为和生态研究，包括对其影响的研究，可能受益于这种瓢虫的非破坏性或非干扰性性别鉴定技术。在实验室和野外研究中评估了 H. axyridis（succinea 颜色形式）的外部形态特征，以确定其性别。第五个可见腹部腹板末端的形状准确地预测了所有检查过的 H. axyridis 的性别。雄性的末端总是凹的，而雌性的末端总是凸的。此外，唇基和前胸的色素沉着均与 H. axyridis 的性别显著相关；雄性的色素沉着浅，而雌性的色素沉着深。随着饲养温度的降低和成虫羽化后时间的增加，雌性的唇基和前胸色素沉着从浅变深。雄性的色素沉着仅受饲养温度降低的影响。通过野外采集的验证表明这些预测因子是准确的。然而，唇基色素沉着是一种更理想的性别鉴定特征，因为它更准确且更容易获取。因此，我们建议在野外使用唇基色素沉着来鉴定 H. axyridis 的性别。讨论了这种诊断技术对该天敌的应用和基础研究的意义。
