生命能量被快速消耗,，最終導(dǎo)致英年早逝——這似乎是動物王國的魔咒,。一只動物消耗越多能量，它的身體就會產(chǎn)生越多的自由基和不穩(wěn)定,、破壞細胞的分子,，這樣的分子過多便會縮短壽命。
然而,，Glanville的豹紋蝶（慶網(wǎng)蛺蝶）似乎并沒有遵循這個備忘錄,。當(dāng)對這種有雜亂圖案的昆蟲的代謝速率進行測量時,，研究者發(fā)現(xiàn)這些蝴蝶在飛行時耗費最多的能量，但也活得最長,，無論它們是在實驗室范圍內(nèi)還是被放飛到芬蘭的草甸上,。這些發(fā)現(xiàn)表明，氧化壓力——自由基和有害分子的長期存在——與壽命之間的聯(lián)系可能比之前想得更加復(fù)雜,。
其全速飛行的能力表明,，該蝴蝶很自然地擁有更好的形態(tài)——無論是通過更有營養(yǎng)的食物還是個體遺傳實現(xiàn)的——來推翻高度新陳代謝的有害副作用。研究者上個月在《實驗生物學(xué)雜志》的網(wǎng)站上發(fā)表了這一研究結(jié)果,。不過他們也懷疑適應(yīng)高性能飛行的蝴蝶是否可能已經(jīng)進化到有辦法在高速新陳代謝時保護自己,。(生物谷Bioon.com)
doi: 10.1242/jeb.080739
PMC:
PMID:
A long life in the fast lane: positive association between peak metabolic rate and lifespan in a butterfly
Kristjan Niitepõld1,* and Ilkka Hanski2
High peak metabolic may provide performance advantage, but it may also entail a physiological cost. A long-held assumption is that high mass-specific energy expenditure is associated with short lifespan. To examine the relationship between energy expenditure and lifespan we asked two questions. First, do individuals have a consistent rate of metabolism throughout their life? Second, is metabolic rate correlated with lifespan? We analysed the repeatability of measurements of resting (RMR) and peak flight metabolic rate (MRpeak) throughout the life of the Glanville fritillary butterfly (Melitaea cinxia). Measurements of MRpeak showed significant repeatability. Senescence occurred only shortly before death. RMR showed a U-shaped relationship with age and very low repeatability. Intraspecific association between metabolic rates and lifespan was tested under three conditions: in the laboratory, under field conditions, and in a laboratory experiment with repeated flight treatments. There was a significant correlation between MRpeak and lifespan in all three experiments, but the correlation was positive, not negative. RMR was not correlated with lifespan. Both MRpeak and lifespan may reflect physiological condition and be therefore positively correlated. Individuals with a large resource pool may be able to invest in mechanisms that slow down ageing. Individuals with high metabolic capacity may also possess adaptations against ageing. Molecular polymorphism in the gene phosphoglucose isomerase (Pgi) was significantly associated with both MRpeak and lifespan, and may have coevolved with defence mechanisms against senescence. Generalisations such as 'live fast, die young' may be too simple to explain the complex processes affecting ageing and lifespan.
