Entomology

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Author: search.filters.author.Chen, Mengyao

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    Establishment of molecular genetic approaches to study gene expression and function in an invasive hemipteran, Halyomorpha halys
    (Springer Nature, 2017-10-18) Lu, Yong; Chen, Mengyao; Reding, Katie; Pick, Leslie
    Hemiptera is a large clade of insects understudied in terms of developmental biology. Halyomorpha halys, the Brown Marmorated Stink Bug (BMSB, referred to throughout as H. halys), is an invasive hemipteran pest of the mid-Atlantic region of the USA that has rapidly spread to other regions in recent years, devastating a wide range of crops using a piercing and sucking mechanism. Its phylogenetic position, polyphagous habits, and rapid spread in the USA suggested that H. halys would be an ideal system to broaden our knowledge of developmental mechanisms in insects. We and others previously generated transcriptome sequences from different life stages of this insect. Here, we describe tools to examine gene expression patterns in whole-mount H. halys embryos and to test the response of H. halys to RNA interference (RNAi). We show that spatial and temporal patterns of gene expression in H. halys can be effectively monitored by both immunostaining and in situ hybridization. We also show that delivery of dsRNA to adult females knocks down gene function in offspring, using the homeotic gene Sex combs reduced (Scr). Knockdown of Hh-Scr resulted in dramatic malformations of the mouthparts, demonstrating for the first time that RNAi is effective in this species. Our results suggest that, despite difficulties with long-term laboratory culture of H. halys, this species shows promise as a developmental system.
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    HEMIPTERAN INSECTS AS MODELS FOR UNDERSTANDING SEGMENTATION
    (2018) Chen, Mengyao; Pick, Leslie; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Although segmentation is highly conserved in arthropods, diverse mechanisms underlie segmentation. Pair-rule genes (PRGs) are a group of genes controlling segmentation in Drosophila melanogaster, a holometabolous insect. While Drosophila are long-germ insects, most insects add segments sequentially. Studying the role of PRGs in sequentially-segmenting species will provide a deeper understanding in terms of developmental biology. Here, I studied two such insects: Halyomorpha halys and Oncopeltus fasciatus, hemimetabolous insects in a sister order to Holometabola. I annotated segmentation genes in the Halyomorpha genome and tested its response to RNA interference which I showed to be effective in this species for the first time. I further showed that three orthologs of Drosophila PRGs are present in the Oncopeltus genome and are expressed during stages at which segments are specified. Surprisingly, only one of these orthologs is expressed in a PR-pattern, indicating that PRG expression and function have changed during insect evolution.