State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, and Centre for Excellence in Life and Palaeoenvironment, Chinese Academy of Sciences, Nanjing 210008, People's Republic of China.
Section Entomology, Naturalis Biodiversity Centre, 2300 RA Leiden, The Netherlands.
Proc Biol Sci. 2022 Jul 13;289(1978):20220447. doi: 10.1098/rspb.2022.0447.
Brood care enhances offspring fitness and survival by providing protection or feeding through parents (commonly by females). It has evolved independently multiple times in animals, e.g. mammals, birds, dinosaurs and arthropods, especially various lineages of insects, and has significant implications for understanding the emergence of sociality of insects. However, few fossil insects document such an ephemeral behaviour directly. New exceptional fossils of the water boatman from the Middle-Late Jurassic Daohugou biota ( 163.5 Ma, northeastern China), with adult females bearing clutches of eggs on their left mesotibia, provide a unique brooding strategy (asymmetric egg-carrying behaviour) unknown in all extinct and extant insects. Our discovery represents the earliest direct evidence of brood care among insects, pushing back by more than 38 million years, indicating that relevant adaptations associated with maternal investment of insects can be traced back to at least the Middle-Late Jurassic, and highlighting the existence of diverse brooding strategies in Mesozoic insects. In addition, our discovery reveals that a specialized trawl-like filter-capture apparatus of . probably represents pre-adaptions originally used for trapping coeval anostracan (fairy shrimp) eggs for food.
亲代（通常为雌性）通过提供保护或喂养来照顾卵和幼虫，从而提高后代的适应度和存活率。这种行为在动物中独立进化了多次，例如哺乳动物、鸟类、恐龙和节肢动物，尤其是各种昆虫谱系，这对理解昆虫社会性的出现具有重要意义。然而，很少有化石昆虫能直接记录这种短暂的行为。来自中-晚侏罗世道虎沟生物群（163.5Ma，中国东北地区）的水生甲虫新的异常化石，成年雌性左中胫上带有卵囊，提供了一种在所有已灭绝和现存昆虫中都未知的独特的育雏策略（不对称的带卵行为）。我们的发现代表了昆虫中亲代育幼的最早直接证据，这一发现将其回溯到 3800 多万年前，表明与昆虫母体投资相关的相关适应可以追溯到至少中-晚侏罗世，并强调了中生代昆虫中存在多样化的育雏策略。此外，我们的发现表明，可能原本用于捕捉同时代的鳃足类（丰年虾）卵作为食物的. 的专门的拖网状过滤捕捉器，代表了原始的预适应。
