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Megachile rotundata

    Summary
    Type
    organism
    Genus
    Megachile
    Species
    rotundata
    Common Name
    Alfalfa leafcutting bee
    Description

    The alfalfa leafcutting bee, Megachile rotundata F. (Megachildae) is a Eurasian solitary bee species that was inadvertently introduced to North America sometime before the 1940s. By the mid 1950s, M. rotundata had become established in the farming regions of western United States. With the discovery of M. rotundata’s pollination impact on alfalfa seed production, early efforts to increase its populations near alfalfa fields were undertaken a few years later. Currently, M. rotundata is the most intensely managed solitary bee species in the world and is surpassed only by the honey bee for its economic impact.

    Females are gregarious cavity nesters constructing nests composed of leaf pieces in a linear series of cells in naturally occurring cavities or in artificial nesting boards. In most North American latitudes, M. rotundata emerge in late June and early July. Females provision each cell with nectar and pollen, lay a single egg and seal the cell before starting the construction of the next cell. The larvae will develop through five larval instars, spin a cocoon and enter a prepupal diapause and overwinter. A portion of the larvae laid in early spring will avert diapause and produce a second generation of bees. The second generation is problematic to farmers. Depending on the length of the growing season the larvae of the summer generation of females may enter diapause and overwinter. Therefore, in some years the second generation will result in an increased number of bees entering diapause and available for the next growing season. But if the growing season is too short, the larvae will not have sufficient time to complete development and will not be able to enter diapause. Besides influencing the total number of bees entering diapause each year, the second generation has been implicated as a major factor in the spread of chalk brood, the primary disease of M. rotundata. The development of a M. rotundata genome database is an important advancement for understanding basic physiology and disease management of this important pollinator.

    Publication
    Kapheim KM, Pan H, Li C, Salzberg SL, Puiu D, Magoc T, Robertson HM, Hudson ME, Venkat A, Fischman BJ, Hernandez A, Yandell M, Ence D, Holt C, Yocum GD, Kemp WP, Bosch J, Waterhouse RM, Zdobnov EM, Stolle E, Kraus FB, Helbing S, Moritz RF, Glastad KM, Hunt BG, Goodisman MA, Hauser F, Grimmelikhuijzen CJ, Pinheiro DG, Nunes FM, Soares MP, Tanaka ÉD, Simões ZL, Hartfelder K, Evans JD, Barribeau SM, Johnson RM, Massey JH, Southey BR, Hasselmann M, Hamacher D, Biewer M, Kent CF, Zayed A, Blatti C, Sinha S, Johnston JS, Hanrahan SJ, Kocher SD, Wang J, Robinson GE, Zhang G. Social evolution. Genomic signatures of evolutionary transitions from solitary to group living. . Science (New York, N.Y.). 2015 Jun 05; 348(6239):1139-43.
    Organism Image
    Image Credit
    Theresa Pitts-Singer, U.S. Department of Agriculture. Public domain.
    Assembly Stats
    Contig N50
    NA
    GC Content
    40.54
    Scaffold N50
    1699680
    Other Information
    Community Contact
    George Yocum, USDA-ARS; Karen M. Kapheim, Utah State University; Hailin Pan, China National GeneBank
    Analyses
    Name Program
    Megachile rotundata NCBI Annotation Release 101 NCBI Eukaryotic Genome Annotation Pipeline
    Functional annotation of NCBI Megachile rotundata Annotation Release 101 AgBase functional annotation pipeline
    Megachile rotundata genome assembly MROT_1.0 (GCF_000220905.1) SOAPdenovo Assembler
    Megachile rotundata gene predictions v1.1 Custom
    Diapause development RNAseq, combined assembly Tuxedo Suite (TopHat2 v2.0.10/Cufflinks v2.1.1/Cuffmerge v1.0.0)