1. Recently, reports of insect declines prompted concerns with respect to the state of insects at a global level. Here, we present the results of longer‐term insect monitoring from two locations in the Netherlands: nature development area De Kaaistoep and nature reserves near Wijster.
2. Based on data from insects attracted to light in De Kaaistoep, macro‐moths (macro‐Lepidoptera), beetles (Coleoptera), and caddisflies (Trichoptera) have declined in the mean number of individuals counted per evening over the period of 1997–2017, with annual rates of decline of 3.8, 5.0 and 9.2%, respectively. Other orders appeared stable [true bugs (Hemiptera: Heteroptera and Auchenorrhyncha) and mayflies (Ephemeroptera)] or had uncertainty in their trend estimate [lacewings (Neuroptera)].
3. Based on 48 pitfall traps near Wijster, ground beetles (Coleoptera: Carabidae) showed a mean annual decline of 4.3% in total numbers over the period of 1985–2016. Nonetheless, declines appeared stronger after 1995.
4. For macro‐moths, the mean of the trends of individual species was comparable to the annual trend in total numbers. Trends of individual ground beetle species, however, suggest that abundant species performed worse than rare ones.
5. When translated into biomass estimates, our calculations suggest a reduction in total biomass of approximately 61% for macro‐moths as a group and at least 42% for ground beetles, by extrapolation over a period of 27 years. Heavier ground beetles and macro‐moths did not decline more strongly than lighter species, suggesting that heavy species did not contribute disproportionately to biomass decline.
6. Our results broadly echo recent reported trends in insect biomass in Germany and elsewhere.

中文翻译：

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荷兰甲虫，飞蛾和甲虫的数量下降

1. 最近，有关昆虫数量下降的报道引起了人们对全球昆虫状况的关注。在这里，我们介绍了来自荷兰两个地点的长期昆虫监测结果：自然开发区De Kaaistoep和威斯特附近的自然保护区。
2. 根据De Kaaistoep吸引昆虫的数据，在1997-2017年期间，每天夜蛾的平均飞蛾数量（宏鳞翅目），甲虫（鞘翅目）和甲壳纲（Trichoptera）有所下降，年增长率分别为3.8％，5.0％和9.2％。其他订单似乎稳定[真正的昆虫（半翅目：异翅目和Auchenorrhyncha）和可能的昆虫（E翅目）]或它们的趋势估计不确定（[虫（Neuroptera）]。
3. 基于维伊斯特（Wijster）附近的48个陷阱陷阱，地上的甲虫（鞘翅目（Coleoptera：Carabidae））在1985-2016年期间的年平均总数下降了4.3％。尽管如此，1995年以后下降趋势更加明显。
4. 对于大型蛾，单个物种趋势的平均值与总数的年度趋势相当。但是，单个甲壳虫物种的趋势表明，丰富的物种表现比稀有物种差。
5. 如果将其转化为生物量估算值，我们的计算表明，通过27年的推断，整个蛾类的总生物量减少了约61％，地面甲虫至少减少了42％。较重的甲虫和大蛾的降落没有比较轻的物种更强烈，这表明重的物种并没有对生物量的下降做出不成比例的贡献。
6. 我们的研究结果大致上反映了德国和其他地区最近报道的昆虫生物量趋势。