Sergeev M.G. 2017. [The Migratory locust Locusta migratoria (Linnaeus, 1758) (Orthoptera: Acrididae) near the species range boundary: South Siberia as the region of potential outbreaks] // Euroasian Entomological Journal. Vol.16. No.5: 407–415 [in Russian, with English sunnary].
Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, Frunze Str. 11, Novosibirsk 630091 Russia. Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090 Russia.
ABSTRACT. The main peculiarities of morphology, taxonomy and distribution of the Migratory locust Locusta migratoria (Linnaeus, 1758) are characterized. Updated versions of the keys to adults and larvae of all genera and species of the tribe Locustini known from Siberia are provided. The general range of L. migratoria Migratory locust is described, particularly in respect of its distribution over the northern part of Eurasia, especially on West Siberian Plane, in the Altay-Sayan Mts. and Transbaikal (Dauria). The conditions under which a dense population of this species was found for the first time in Tuva (the Republic of Tyva) in the Altay-Sayan Mts, near the hypersaline Shara Lake, are described. This newly discovered population inhabited several adjacent habitats: local dry meadows with dominated by Achnatherum splendens (Trin.) Nevski on the lake terraces, some meadows with short mesophilous grasses along a small stream, and halophytic meadows in wide depressions near the lake. L. migratoria was very abundant (1 per m2) on the lake terraces. The locust aggregations were not observed either adults or hoppers. The main traits were typical of the solitary form, namely the high and arched pronotal crests of adults, the ratio of tegmen length to posterior femur length, and uniform body colouration of hoppers. However, study of some adults indicated that the population could be characterized by the level of gregariousness. The ratios of posterior femur length to maximum width of head and pronotum length to maximum width of head partially overlapped the values typical for gregarious forms of this locust. Hence, near the northern boundary of its range it occupied some new and unusual types of habitat. Comparative maps of this species to denote range boundaries and of growing degree units above 10 °C in North Eurasia show that opportunities for both full development of locusts and ability to disperse are limited by warmth accumulations and duration of summer season as defined by the sum of warm temperatures more than 1650–1700°. It should be noted that in South Siberia, especially in the Altay-Sayan Mts, climatic changes in recent decades, particularly warming, are highly significant and could cause the tendency to possible increasing of both general number of local populations of the Migratory locust and its common abundance. This will be able to result in some serious problems for plant protection.
KEY WORDS: grasshopper, Migratory locust, Acrididae, distribution, range, population, gregarious phase, outbreak, Siberia, Tuva, warming.