The sub-lethal effects of repeated freezing in the woolly bear caterpillar Pyrrharctia isabella
The sub-lethal effects of repeated freezing in the woolly bear caterpillar Pyrrharctia isabella
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DOI：
10.1242/jeb.054569
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发表时间：
2011-04-01
影响因子：
2.8
通讯作者：
Sinclair, Brent J.
中科院分区：
文献类型：
--
作者：
Marshall, Katie E.;Sinclair, Brent J.
反复的冻融循环是常见的，并且随着许多温带地区气候变化而增加频率，但对它们对抗冻昆虫的影响的了解非常有限。我们调查了反复冻融对耐冻性的末龄幼虫的蛾Pyrrharctia isabella（鳞翅目：Artiidae）的影响，无论是单一的持续35。h冷冻或5个7 h冷冻。亚致死效应通过以下三大类措施的变化进行量化：（1）抗寒性，（2）代谢率和能量储备，以及（3）真菌孢子攻击后的存活率。反复冻融循环使死亡率增加至近30%，并增加马氏管和血细胞的组织损伤。反复冷冻使毛虫甘油浓度增加0.82。moll（-1）。反复冷冻后，代谢率或能量储备没有变化。这是第一次，我们报告增加的生存后，免疫挑战的毛虫冷冻后，并建议这可能与冷冻过程中受伤。我们认为，在P. isabella毛虫中，冷冻损伤的修复可能性很小，重复的冻融循环可能对该物种的生存构成重大挑战。
Repeated freeze-thaw cycles are common and are increasing in frequency with climate change in many temperate locations, yet understanding of their impact on freeze-tolerant insects is extremely limited. We investigated the effects of repeated freezing and thawing on the freeze-tolerant final instar caterpillars of the moth Pyrrharctia isabella (Lepidoptera: Arctiidae) by subjecting individuals to either a single sustained 35. h freeze or five 7h freezes. Sub-lethal effects were quantified with changes in three broad groups of measures: (1) cold hardiness, (2) metabolic rate and energy reserves and (3) survival after challenge with fungal spores. Repeated freeze-thaw cycles increased mortality to almost 30% and increased tissue damage in Malpighian tubules and hemocytes. Repeated freezing increased caterpillar glycerol concentration by 0.82. moll(-1). There were no changes in metabolic rate or energy reserves with repeated freezing. For the first time, we report increased survival after immune challenge in caterpillars after freezing and suggest that this may be linked to wounding during freezing. We suggest that little repair of freezing damage is possible in P. isabella caterpillars and repeated freeze-thaw cycles may present significant challenges to survival in this species.