An endoparasitoid Cretaceous fly and the evolution of parasitoidism
Qingqing Zhang, Junfeng Zhang, Yitao Feng, Haichun Zhang, Bo Wang
针虻生态复原图
日前，中科院南京地质古生物所研究员张俊峰团队在白垩纪缅甸琥珀中发现了拟寄生的虻类昆虫，属双翅目独须虻科，研究人员将其命名为“夏氏针虻”。这一发现为中侏罗到晚白垩的拟寄生昆虫的大分化假说提供了有力证据。研究成果发表于《The Science of Nature》。
本次发现的针虻是独须虻科最年轻的化石记录，其高度发达的针筒状产卵器和特化的三趾状的爪为其拟寄生习性提供了坚实证据，该研究表明独须虻科至少在侏罗纪就演化出了拟寄生行为和相应的形态适应。
昆虫的拟寄生行为是一种特殊的捕食行为，也是昆虫演化史上一个重要创新，代表了陆地生态系统中一种新的取食模式。早侏罗世的蜂类是被广泛认可的最早的拟寄生性昆虫。此外，一些白垩纪捻翅目和鞘翅目幼虫也被认为是拟寄生性昆虫。尽管现今双翅目昆虫的许多类群都具有拟寄生行为，但明确的中生代拟寄生性双翅目化石非常罕见。
来源：中国科学报 李瑜
ABSTRACT:
Parasitoidism is a key innovation in insect evolution, and parasitoid insects, nowadays, play a significant role in structuring ecological communities. Despite their diversity and ecological impact, little is known about the early evolution and ecology of parasitoid insects, especially parasitoid true flies (Diptera). Here, we describe a bizarre fly, Zhenia xiai gen. et sp. nov., from Late Cretaceous Burmese amber (about 99 million years old) that represents the latest occurrence of the family Eremochaetidae. Z. xiai is an endoparasitoid insect as evidenced by a highly developed, hypodermic-like ovipositor formed by abdominal tergites VIII + IX that was used for injecting eggs into hosts and enlarged tridactylous claws supposedly for clasping hosts. Our results suggest that eremochaetids are among the earliest definite records of parasitoid insects. Our findings reveal an unexpected morphological specialization of flies and broaden our understanding of the evolution and diversity of ancient parasitoid insects.
