Zhigulskaya Z.A., Chesnokova S.V.

Insufficient cold resistance and the eastern boundary of the distribution range of ant Lasius fuliginosus (Hymenoptera: Formicidae)

Number: 406, Pages: 14 - 20

The hypothesis of insufficient cold resistance as a factor limiting the distribu­tion of the dendrophilous ant Lasius fuliginosus eastward of the city of Novosibirsk is proposed and partially tested; this species has colonies of two million individuals and therefore has a significant biocenotic role. The cold resistance and wintering conditions of this ant species in the vicinity of Novosibirsk are studied. The mean supercooling point in three nests was –14.6 to –18.1°C, down to –23.9°C in the most resistant individuals. The lower lethal temperature does not exceed –12°C. The temperatures in the nests (with 55 cm snow-cover height above it) did not decrease below –1.5°C at 50–60 cm depth during the winter, which indicates wintering temperature conditions comfortable for the ants. The cause of absence of this species in Yakutia, foothills of the Western and Eastern Sayan Mountains, and Tuva, as established by myrmecologists, is likely climatic, initially associated with a decrease in the amount of solid precipitation under the condition of similar or lower air temperatures from Western to Central Siberia, in particular by a third in the vicinity of the city of Krasnoyarsk in comparison to the vicinity of Novosibirsk.

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