Bartlett Jesamine C, Convey Peter, Hayward Scott A L
1School of Biosciences, University of Birmingham, Edgbaston, B15 2TT UK.
2British Antarctic Survey, NERC, High Cross, Madingley Road, Cambridge, CB3 0ET UK.
Polar Biol. 2019;42(1):115-130. doi: 10.1007/s00300-018-2403-5. Epub 2018 Sep 29.
Knowledge of the life cycles of non-native species in Antarctica is key to understanding their ability to establish and spread to new regions. Through laboratory studies and field observations on Signy Island (South Orkney Islands, maritime Antarctic), we detail the life stages and phenology of (Schaeffer 1914), a brachypterous chironomid midge introduced to Signy in the 1960s from sub-Antarctic South Georgia where it is endemic. We confirm that the species is parthenogenetic and suggest that this enables to have an adult emergence period that extends across the entire maritime Antarctic summer season, unlike its sexually reproducing sister species which is itself endemic to the Antarctic Peninsula and South Shetland Islands. We report details of previously undescribed life stages, including verification of four larval instars, pupal development, egg gestation and development, reproductive viability and discuss potential environmental cues for transitioning between these developmental stages. Whilst reproductive success is limited to an extent by high mortality at eclosion, failure to oviposit and low egg-hatching rate, the population is still able to potentially double in size with every life cycle.
了解南极非本地物种的生命周期是理解它们在新区域定殖和扩散能力的关键。通过在西格尼岛（南奥克尼群岛，南极海洋地区）的实验室研究和实地观察，我们详细阐述了1960年代从亚南极南乔治亚岛引入西格尼岛的短翅摇蚊（1914年舍费尔命名）的生活阶段和物候特征，该物种在南乔治亚岛为特有种。我们证实该物种为孤雌生殖，并认为这使得其成虫羽化期能够贯穿整个南极海洋夏季，这与它有性生殖的姐妹物种不同，后者是南极半岛和南设得兰群岛的特有种。我们报告了此前未描述的生活阶段的细节，包括对四龄幼虫、蛹发育、卵的孕育和发育、繁殖活力的验证，并讨论了这些发育阶段之间转换的潜在环境线索。虽然羽化时的高死亡率、不产卵和低孵化率在一定程度上限制了繁殖成功率，但该种群每个生命周期仍有可能实现数量翻倍。
