Université de Strasbourg, DIHP Dynamique des Interactions Hôte Pathogène UR 7292, 67000 Strasbourg, France.
Parasite. 2021;28:45. doi: 10.1051/parasite/2021045. Epub 2021 May 26.
The invasive mosquito Aedes japonicus japonicus (Theobald, 1901) settled in 2013 in the Alsace region, in the northeast of France. In this temperate area, some mosquito species use diapause to survive cold winter temperatures and thereby foster settlement and dispersal. This study reports diapause and its seasonality in a field population of Ae. japonicus in the northeast of France. For two years, eggs were collected from May to the beginning of November. They were most abundant in summer and became sparse in late October. Diapause eggs were determined by the presence of a fully developed embryo in unhatched eggs after repeated immersions. Our study showed effective diapause of Ae. japonicus in this part of France. At the start of the egg-laying period (week 20), we found up to 10% of eggs under diapause, and this rate reached 100% in October. The 50% cut-off of diapause incidence was determined by the end of summer, leading to an average calculated maternal critical photoperiod of 13 h 23 min. Interestingly, diapause was shown to occur in part of the eggs even at the earliest period of the two seasons, i.e. in May of each year. Even though we observed that the size of eggs was positively correlated with diapause incidence, morphology cannot be used as the unique predictive indicator of diapause status due to overlapping measurements between diapausing and non-diapausing eggs. This study provides new knowledge on diapause characterisation and invasive traits of Ae. japonicus.
入侵蚊种日本伊蚊（Theobald，1901）于 2013 年在法国东北部的阿尔萨斯地区定殖。在这个温带地区，一些蚊子物种通过滞育来适应寒冷的冬季温度，从而促进定居和扩散。本研究报告了法国东北部野外种群中日本伊蚊的滞育及其季节性。在两年的时间里，从 5 月到 11 月初收集了卵。夏季数量最多，10 月下旬逐渐稀疏。滞育卵通过在反复浸泡后未孵化卵中发现完全发育的胚胎来确定。我们的研究表明，法国这一地区的日本伊蚊具有有效的滞育现象。在产卵期开始时（第 20 周），我们发现滞育卵的比例高达 10%，到 10 月这一比例达到 100%。通过夏季末确定滞育发生率的 50%截断值，导致平均计算出的母体临界光周期为 13 小时 23 分钟。有趣的是，滞育现象甚至在每年的两个季节的最早时期（即 5 月）也会出现在部分卵中。尽管我们观察到卵的大小与滞育发生率呈正相关，但由于滞育卵和非滞育卵之间的测量值重叠，形态不能作为滞育状态的唯一预测指标。本研究为日本伊蚊的滞育特征和入侵特性提供了新的知识。
