Female Harmonia axyridis (Coleoptera: Coccinellidae) produce a sex pheromone to attract males. In the present study, we tested two hypotheses: (i) production of sex pheromone in H. axyridis is conditioned by perception of prey in their vicinity, and (ii) virgin females invest in the production of the sex pheromone, while mated females reduce their pheromone emissions. To test the first hypothesis, newly hatched larvae were divided into three groups: those fed with Ephestia kuehniella eggs, those fed with pea aphids, and those exposed to aphid volatile cues but fed with Ephestia eggs. All females produced a pheromone blend of five-components in similar relative proportions, but with contrasting absolute quantities: Females fed with Ephestia eggs produced lower amounts of pheromone (0.5 ± 0.4 ng.female⁻¹), compared to females fed with aphids (44.2 ± 24.4 ng.female⁻¹). The females of the third group produced intermediate concentrations of pheromone (6.0 ± 3.2 ng.female⁻¹). To test the second hypothesis, two groups of lady beetles were made: one group of females was placed in the presence of males, while females of the other group were not. Mated and virgin females produced statistically similar amounts of pheromone (144.1 ± 49.7 ng and 43.7 ± 24.1 ng.female⁻¹, respectively). These results suggest that H. axyridis females initiate pheromone production upon exposure to volatile cues released by their aphids prey. Females continue to release sex pheromone after mating, probably to increase the chance of multiple mating which is known to improve egg fertility.

中文翻译：

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甲虫瓢虫中性信息素的产生取决于蚜虫的存在，而不是取决于交配状态。

雌性Harmonia axyridis（鞘翅目：Coccinellidae）产生性信息素以吸引雄性。在本研究中，我们测试了两个假设：（i）腋臭吸虫中性信息素的产生受周围猎物感知的影响；（ii）处女雌性投资性信息素的产生，而交配雌性则减少性信息素的产生。它们的信息素排放。为了检验第一个假设，将刚孵出的幼虫分为三组：饲喂库氏埃弗氏菌卵的幼虫，饲喂豌豆蚜虫的幼虫，以及暴露于蚜虫易变线索但饲育埃弗氏菌的卵的幼虫。所有雌性都以相似的相对比例生产了五成分的信息素混合物，但是绝对量却相反：与饲喂蚜虫的雌性（44.2±24.4 ng 。雌性^-1）相比，依弗希斯蛋产生的信息素含量较低（0.5±0.4 ng。雌性^-1）。第三组的雌性产生中间浓度的信息素（6.0±3.2 ng 。雌性^-1）。为了检验第二个假设，制作了两组瓢虫：一组雌性放在雄性的面前，而另一组雌性则没有。交配和初生雌性产生的信息素在统计学上相似（分别为144.1±49.7 ng和43.7±24.1 ng 。雌性^-1）。这些结果表明，H。ayyridis雌性一旦接触到其蚜虫猎物释放的挥发性信号，就会开始产生信息素。雌性交配后继续释放性信息素，这可能会增加多次交配的机会，众所周知，这种交配会提高卵子的生育能力。