Diorhabda elongata has recently been released at several study sites in the western U.S. as a biocontrol agent of saltcedar (Tamarix spp.) The success of the beetle as a control agent will be in part determined by the ability of a single population to expand rapidly under diverse field conditions. Key components of population expansion include the timing and duration of diapause. For this reason we have characterized the environmental factors controlling diapause induction and we discuss the results in light of field data indicating early entry into diapause.
D. elongata overwinters in reproductive diapause. Diapausing females are distinguished by undeveloped ovaries, a lack of vitellogenic oocytes and circulating vitellogenin, and a well developed fat body. Diapausing males have undeveloped accessory glands and well developed fat body. The critical photoperiod for induction is 15L:9D and it is only slightly modified by temperature. Pupae and adults are sensitive to photoperiod and even reproductive adults can be switched to a diapause state by a switch to 12L:12D.
Species 1: Coleoptera Chrysomelidae Diorhabda elongata
Keywords: diapause, biocontrol
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