The Bogong moth Agrotis infusa is well known for its remarkable long‐distance migration – a return journey from the plains of southeast Australia to the Australian Alps – as well as for its cultural significance for Indigenous Australians. Each spring, as many as four billion moths are estimated to arrive in the Australian Alps to aestivate in cool mountain caves and in boulder fields, bringing with them a massive annual influx of energy and nutrients critical for the health of the alpine ecosystem. However, a massive decline in moths present at their aestivation sites has occurred over the past 3 years, with only a few individuals present where hundreds of thousands could earlier be found. In order to understand the possible sources of decline, we analysed historical records of Bogong moth numbers at aestivation sites in the Australian Alps, including observations on Mt. Gingera (NSW) in the early 1950s, observations from 1980 onwards in the Snowy Mountains (NSW) and an almost‐unbroken series of observations each summer over the past 53 years in three caves at different elevations on Mt. Buffalo (Victoria). This analysis shows that moth numbers were probably steady from 1951 until about 1980, fluctuated and slowly fell from then until 2016 and dramatically crashed in 2017. In the Murray–Darling Basin, the main winter breeding ground of Bogong moths, changes in farming practices, such as increasing land clearing for crops (which has removed around a quarter of a billion moths annually from the mountains compared to pre‐European levels), has probably driven some of the decline in Bogong moth numbers observed from 1980 to 2016. The impact of insecticide remains unclear and is in urgent need of further study. Even though we found little evidence that increasing global temperatures per se are responsible for the Bogong moth decline, the Australian climate has nonetheless become drier and warmer over past decades, possibly hampering the survival of immature stages in the breeding areas and confining adult aestivation to gradually higher elevations. The crash in moth numbers from 2017 is most likely due to the recent severe drought in the moth's breeding grounds.

中文翻译：

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澳大利亚博贡蛾 Agrotis infusa（鳞翅目：夜蛾科），1951 年至 2020 年：衰退和崩溃

博贡蛾小地老虎以其非凡的长途迁徙（从澳大利亚东南部平原到澳大利亚阿尔卑斯山的往返旅程）及其对澳大利亚土著人的文化意义而闻名。每年春天，估计有多达 40 亿只飞蛾抵达澳大利亚阿尔卑斯山，在凉爽的山洞和巨石田里过夏，每年带来大量对高山生态系统健康至关重要的能量和营养物质。然而，在过去的三年里，夏眠地点的飞蛾数量大幅减少，以前发现的飞蛾数量有数十万只，现在只剩下几只。为了了解下降的可能来源，我们分析了澳大利亚阿尔卑斯山夏眠地点博贡蛾数量的历史记录，包括 1950 年代初对 Mt. Gingera（新南威尔士州）的观测，以及 1980 年以来在大雪山（新南威尔士州）的观测。 ）以及过去 53 年里每年夏天在布法罗山（维多利亚州）不同海拔的三个洞穴中几乎不间断的一系列观测。这项分析表明，从 1951 年到 1980 年左右，蛾类数量可能保持稳定，从那时起一直到 2016 年，蛾类数量出现波动并缓慢下降，并在 2017 年急剧下降。在墨累-达令盆地，博贡蛾的主要冬季繁殖地，耕作方式的变化，例如增加农作物土地清理（与欧洲出现之前的水平相比，每年从山上清除约 25 亿只飞蛾），可能导致 1980 年至 2016 年间观察到的博贡蛾数量有所下降。杀虫剂尚不清楚，迫切需要进一步研究。尽管我们没有发现证据表明全球气温升高本身是博贡蛾数量减少的原因，但澳大利亚气候在过去几十年中变得更加干燥和温暖，可能会阻碍繁殖区未成熟阶段的生存，并逐渐限制成虫的夏眠。海拔较高。2017 年以来，飞蛾数量大幅下降，很可能是由于最近飞蛾繁殖地的严重干旱造成的。