PhD Student from the College of Life Sciences Published Paper in Authoritative International Journal on Botany2021-10-26

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  Recently, the innovation team for insect evolution of the College of Life Sciences of CNU under the direction of the Ministry of Education worked with international peers and found stinging mealybug fossils and holes left by insect stinging on leaves of Pandemophyllum kvacekii, an extinct near-modern lauraceae plant among Rose Creek fossil flora in America from the early Cretaceous Dakota Formation (103 million years ago). This is the earliest direct evidence to show that coccids feed on angiosperms by stinging and that the mealybugs feed on the leaves of P. kvacekii of lauraceae by stinging.

  In addition to mealybugs found on P. kvacekii leaves, 2 other types of coccid mark fossils were also found on some fossilized branches of angiosperms. By analyzing the size and distribution of the marks of these 2 species, they believed that both hemispherical and elliptic marks were likely to be undetermined species of coccids (Coccidae genus et species incertae sedis, morphotype 2., morphotype 3.). They record some stinging damage marks made by coccid feeding on lauraceae leaves in the early Cretaceous and are also the earliest fossil records of female mealybug adults sucking on early angiosperms. They are approximately 55 million years earlier than the previous fossil record of diaspididae found on angiosperm leaves of the Messel and Eckfeld Maar flora in Germany during the middle Eocene. At present, still 47 mealybug species parasitize 20 lauraceae species. One mealybug species can parasitize many lauraceae species. One lauraceae species can be parasitized by many mealybug species at the same time.

  Current molecular system development analysis suggests that mealybugs originated no later than the late Jurassic (about 150 million years ago). This research provides direct evidence for the exploration of insects’ feeding on angiosperms by stinging, suggesting that the herbivory relationship between mealybugs and lauraceae plants was formed and differentiated before the expansion of angiosperms in the Cretaceous. The result was published online on August 11, 2021 in the New Phytologist (IF="10.151, top 7/235, Plants" Sciences), a famous international periodic on botany. Xiao Lifang, a PhD student from CNU, is the first author of the paper, and Professor Ren Dong, Conrad C. Labandeira, fellow of the American Museum of Natural History, and Professor David L. Dilcher, fellow of the National Academy of Sciences of America are co-corresponding authors. Professor Yair Ben-Dov from the Israel Academy of Agricultural Sciences, Associate Professor S. Augusta Maccracken from the University of Maryland, and Visiting Professor Shih Chungkun from CNU joined in the research.