Research and Innovation Centre, Fondazione Edmund Mach, San Michele All'Adige, TN, Italy.
Parasit Vectors. 2022 Sep 6;15(1):315. doi: 10.1186/s13071-022-05376-7.
Aedes koreicus is an invasive alien mosquito species native to Asia now introduced in several European countries, including northern Italy. In this temperate region, mosquito populations survive cold winter temperatures thanks to diapausing eggs or adults, depending on the species. In its native area, Ae. koreicus was reported to overwinter in the egg stage, but to the best of our knowledge, it is not confirmed whether overwintering eggs are actually diapausing or only in a quiescence stage, i.e., they might hatch as soon as external conditions are favorable. Based on previous laboratory studies, we established a diapausing Ae. koreicus colony, maintained at 21 °C with a photoperiod of 12L:12D. Females were allowed to lay eggs, which were consequently placed in water at different time intervals after oviposition, from 30 days to 5 months. We found that diapausing eggs younger than 3 months have a poor hatching rate, while after about 100 days we observed that almost all eggs hatched. Our findings highlight that water immersion alone did not lead to the hatching of eggs, as age was found to be a significantly important factor. We thus confirm effective diapause, occurring at the egg stage, for Ae. koreicus in a recently invaded area. Moreover, our quantification of diapause duration and hatching success might help in better designing future experiments and improving modeling efforts.
韩国伊蚊是一种原产于亚洲的入侵外来蚊种，现已引入包括意大利北部在内的几个欧洲国家。在这个温带地区，蚊子种群依靠滞育卵或成虫来度过寒冷的冬季，具体取决于物种。在其原生地区，据报道韩国伊蚊以卵期滞育越冬，但据我们所知，尚无法确认越冬卵实际上是否滞育，还是仅处于休眠状态，即一旦外部条件有利，它们就可能孵化。基于先前的实验室研究，我们建立了一个滞育的韩国伊蚊种群，在 21°C 下，光照周期为 12L:12D。允许雌性产卵，随后将卵在产卵后不同时间间隔放置在水中，从 30 天到 5 个月不等。我们发现，滞育卵龄小于 3 个月的孵化率较差，而大约 100 天后，我们观察到几乎所有的卵都孵化了。我们的研究结果表明，仅水浸泡并不能导致卵孵化，因为年龄是一个非常重要的因素。因此，我们证实了在最近入侵的地区，韩国伊蚊在卵期发生有效滞育。此外，我们对滞育持续时间和孵化成功率的量化可能有助于更好地设计未来的实验和改进建模工作。
