Abstract

As a model species to study the geographic variation of cold hardiness in insects, we use ants Lasius flavus from populations of territories separated by thousands of kilometers (southern Finland, the Moscow region, and Amur oblast) and with contrasting climates, from maritime variants to climates differing in degrees of continentality. We measure supercooling points (SCPs) and the temperature at which 50% of the sample perishes (LT_50%) and evaluate overwintering conditions. The data on L. flavus are compared to similar data obtained on L. niger, аs well as to similar measurements in separate nests of L. alienus, L. psammophilus, and L. fuliginosus, which were published earlier. The workers of L. flavus and L. niger have similar values of cold hardiness (LT_50% from –13 to –15°C, minimum average SCP from –24 to –25°C), although these species inhabit different climatic zones and arrange their overwintering chambers at different depths. Such resistance to long-term exposure to negative temperatures is more than sufficient for overwintering, even in the coldest of the studied areas (village of Arkhara, Amur oblast), where the average minimum temperature in January in the ant overwintering chambers at a depth of 50 cm does not fall below –6°C. The variation in cold hardiness and higher values of its parameters in other studied ant species are due to their insufficient preparedness for overwintering. However, the narrow range of SCP values (from –27 to –29°C) in the most cold-resistant individuals of all studied species strongly suggests that their average SCP and LT_50% values are similar to those of L. flavus and L. niger. The similar (or perhaps identical) cold hardiness of the studied ant species appears to be a stable trait of the genus Lasius, as was demonstrated for another ant genus, Myrmica, and which is dissimilar to the genus Formica, in which different species have individual characteristics of cold-resistance. Excessive for overwintering in the warmer climate (southern Finland and Estonia), such cold hardiness appears to have no adaptive value. It can be considered a byproduct of diapause, which is manifested in preadaptation to withstand negative temperature. However, it was this cold hardiness that allowed the ant species to colonize the vast territory of southern Siberia and the Far East.

中文翻译：

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1804 年 Lasius Fabricius 属蚂蚁耐寒性的地理和种内变异（膜翅目，蚁科）

摘要

作为研究昆虫耐寒性地理变异的模型物种，我们使用来自相距数千公里的领土（芬兰南部、莫斯科地区和阿穆尔州）和具有对比气候的蚂蚁Lasius flavus，从海洋变种到大陆性程度不同的气候。我们测量过冷点 (SCP) 和 50% 样品死亡的温度 ( LT _50% ) 并评估越冬条件。将L. flavus的数据与在L. niger上获得的类似数据进行比较，以及与L. Alienus、 L. psammophilus和L. fuliginosus 的不同巢穴中的类似测量值进行比较，之前发布的。L. flavus和L. niger的工人具有相似的耐寒性值（LT _50%从 –13 到 –15°C，最小平均 SCP 从 –24 到 –25°C），尽管这些物种栖息在不同的气候带，并将它们的越冬室安排在不同的深度。这种对长期暴露在负温度下的抵抗力足以越冬，即使在最冷的研究地区（阿穆尔州阿喀拉村），那里的蚂蚁越冬室 1 月的平均最低温度为50 cm 不低于 –6°C。在其他研究的蚂蚁物种中，耐寒性的变化及其参数值较高是由于它们对越冬的准备不足。然而，所有研究物种中最耐寒的个体的 SCP 值范围很窄（从 –27 到 –29°C）强烈表明他们的平均 SCP 和LT _50%值类似于L. flavus和L. niger 的值。所研究的蚂蚁物种的相似（或可能相同）的耐寒性似乎是Lasius属的一个稳定特征，正如另一个蚂蚁属Myrmica所证明的那样，它与Formica属不同，其中不同的物种具有各自的耐寒特性。在温暖的气候（芬兰南部和爱沙尼亚）过冬过度，这种抗寒性似乎没有适应价值。它可以被认为是滞育的副产品，表现为对负温度的预先适应。然而，正是这种耐寒性使蚂蚁物种能够在西伯利亚南部和远东的广阔领土上进行殖民。