Diapause induction in the blueberry maggot was observed in several populations with distinct phenology by taking samples of infested fruit to constant 25 °C. Diapause development was studied using two natural populations with distinct flight period, in June-July and September. Overwintering pupae were kept outdoors and samples were brought to 20 °C at constant intervals. Pupae were also exposed to 1, 4, and 7 ºC for 45, 90, and 135 days. The majority of pupae entered diapause, except in a sample taken on 2 October, indicating the blueberry maggot may have a "short day" response to photoperiod. In early and late populations kept outdoors, diapause is completed from October to December. At constant low temperature, diapause may be completed in 45 d in both populations. Adults will not emerge from diapausing pupae kept continuously at 20 °C. The blueberry maggot synchronizes its life cycle to its host plant fruiting schedule using different postdiapause development rates and not the timing of diapause completion. However, diapause induction is required to modulate postdiapause development. Diapause induction is achieved in the late population because of low soil temperature after pupation. These data show the complexity of controls the blueberry maggot utilizes to remain univoltine while evolving different seasonal synchronies.
Species 1: Diptera Tephritidae Rhagoletis mendax (blueberry maggot)
Keywords: diapause, flight period
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