Effects of photoperiod and relative humidity on diapause termination and post-winter development ofRhagoletis cerasipupae

Abstract

The European cherry fruit fly, Rhagoletis cerasi (Diptera: Tephritidae), is a univoltine species that undergoes obligatory summer–winter diapause at pupal stage in the soil (2–5 cm) beneath host trees. To study the effects of photoperiod and relative humidity on diapause termination and post-winter developmental duration of R. cerasi, pupae collected from Dossenheim (Germany) were exposed to different photoperiod or relative humidity regimes during a chilling period ranging from 2 to 8.5 months. Specifically, pupae were exposed to four photoperiod regimes: (a) light conditions (24L:00D), (b) dark conditions (00L:24D), (c) short photoperiod (08L:16D) and (d) long photoperiod (16L:08D), as well as to three relative humidity regimes: (a) low (40% RH), (b) medium (60% RH) and (c) high (70–80% RH). Data revealed that relative humidity is not a significant predictor of diapause termination, but it affects the post-winter developmental period. Higher relative humidity promotes post-winter pupae development. On the other hand, photoperiod significantly affected both diapause termination and post-winter development of R. cerasi pupae. Light conditions (24L:00D) accelerate adult emergence, particularly for females. Regardless of the photoperiod (24L:00D, 00L:24D, 08L:16D), rates of adult emergence were high (>75%) for chilling intervals longer than 6.5 months. Nonetheless, exposure to a long day photoperiod (16L:08D), during chilling, dramatically reduced the proportion of adult emergence following 6 months exposure to chilling. Our findings broaden the understanding of factors regulating diapause responses in European cherry fruit fly, local adaptation and synchronization of adult emergence with the ripening period of major hosts.

Phenological Mapping of Invasive Insects: Decision Support for Surveillance and Management

“…Modeling of this pest would likely be improved by using a two-phases approach in which photoperiod-cued diapause termination is followed by a degree-day response phase for spring and summer development [106,107]. A similar approach may be appropriate for other invasive insects, such as the Colorado potato beetle [Leptinotarsa decemlineata (Say)] [70], box tree moth [Cydalima perspectalis (Walker)] [92], European cherry fruit fly [Rhagoletis cerasi (L.)] [115], spottedwing drosophila [Drosophila suzukii (Matsumura)] [116], and Asian tiger mosquito [Aedes albopictus (Skuse)] [117].…”

Integrative Proteomic and Phosphoproteomic Analyses Revealed Complex Mechanisms Underlying Reproductive Diapause in Bombus terrestris Queens

“…Various neuroendocrine, molecular, cellular, enzymatic, metabolic, endocrine, and behavioral changes occur during diapause [ 1 , 2 , 3 ]. Diapause usually occurs at species-specific developmental stages (i.e., embryo, larva/nymph, pupa, and adult) [ 1 , 4 , 5 , 6 ]. Reproductive diapause often occurs in overwintering adults upon the arrest of vitellogenesis and ovulation [ 7 ].…”