Wilkens C, Ramløv H
Department of Science, Systems and Models, Roskilde University, Denmark.
Cryo Letters. 2008 Jul-Aug;29(4):293-300.
Larvae of Rhagium mordax empty their guts in preparation for the winter, which alone may enable the larvae to supercool down to -20 degree C or below. This should be sufficient for the larvae to over winter in Denmark if they can prevent inoculation. Antifreeze proteins (AFP) prevent inoculation in adult Rhagium inquisitor and this is also likely in the larvae of R. mordax, as they are in contact with ice in their hibernacula during the winter. arvae of R. mordax probably produce AFPs in the early autumn, however, in some individuals thermal hysteresis (TH) as high as 5.01 degree C was observed in June. Whether or not these individuals have a constant level of TH in their haemolymph all year or if they produce further antifreeze proteins during the autumn is unknown. The lowest measured in January was 7.49 degree C (the highest during this month was 9.08 degree C) so it is likely that the individuals with the highest TH in June also produce AFPs. Haemolymph osmolality in R. mordax is relatively low compared to other freeze avoiding insects, samples taken in January peak at 741 mOsm (+/-127 mOsm). The results of this study are compared with similar data for the closely related R. inquisitor.
Mordax锯天牛幼虫排空肠道以准备过冬，仅此一点就可能使幼虫过冷却至零下20摄氏度或更低。如果能防止接种，这对丹麦的幼虫过冬应该足够了。抗冻蛋白（AFP）可防止成年锯天牛接种， Mordax锯天牛幼虫也可能如此，因为它们在冬季的越冬场所会接触到冰。 Mordax锯天牛幼虫可能在初秋产生AFP，然而，在一些个体中，6月份观察到热滞（TH）高达5.01摄氏度。这些个体的血淋巴中TH水平是否全年恒定，或者它们在秋季是否会产生更多抗冻蛋白尚不清楚。1月份测得的最低值为7.49摄氏度（该月最高值为9.08摄氏度），因此6月份TH最高的个体也可能产生AFP。与其他避免结冰的昆虫相比， Mordax锯天牛的血淋巴渗透压相对较低，1月份采集的样本峰值为741 mOsm（±127 mOsm）。本研究结果与近缘种锯天牛的类似数据进行了比较。
