title: Biochemistry and physiology of overwintering in the mature larva of the pine needle gall midge, Thecodiplosis japonensis (Diptera: cecidomyiidae) in Korea.
abstract: The pine needle gall midge, Thecodiplosis japonensis, overwinters in the soil as a third instar mature larva. The metabolic and physiological compensations and adjustments during its overwintering and acclimation were studied. Field-sampled larvae in 1997/98 winter showed a significant increase in whole-body trehalose by January (5.71 +/- 0.09 vs. 9.41 +/- 0.42 mg/g wet weight) along with a more significant decrease in whole-body glycogen (16.25 +/- 0.18 vs. 5.65 +/- 0.45 mg/g wet weight). Afterwards, there was a partial reconversion of trehalose to glycogen. Moreover, trace amounts of glycerol and steady content of glucose as potential cryoprotectants were found during the overwintering period. Temperature acclimation of field-sampled larvae affects interconversion between trehalose and glycogen. Trehalose accumulation does not affect the larval supercooling capacity. The mean supercooling point of the larvae remained nearly constant at about -20 degree he winter and was unchanged after temperature acclimation. Low temperature survival experiment suggested that the larvae adopt a freeze-avoiding strategy for overwintering.
authors.affiliation: Zoology, Academia Sinica. Beijing 100080, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: H
authors.initials: H
authors.lastname: Gong
authors.forename: H
authors.initials: H
authors.lastname: Park