Erdakov L.N. 2018. [Cyclicity of perennial changes in the density of the dragonfly population Libellula quadrimaculata L., 1758 (Odonata, Libellulidae)] // Euroasian Entomological Journal. Vol.17. No.3: 216–222 [in Russian, with English summary].
Institute of Systematics and Ecology of Animals, Russian Academy of Sciences, Siberian Branch, Frunze Str. 11, Novosibirsk 630091 Russia.
ABSTRACT. Based on the data published in 1969-2009 [Popova, Kharitonov, 2010], a spectrum of the density population fluctuation of Four-spotted Chaser (Libellula quadrimaculata) has been calculated. The resulted spectrum shows seven harmonic components, of which the 6.7-year periodicity predominates by its strength. In the middle frequencies, there is an 11.8-year rhythm. The remaining harmonic components are typical of the high-frequency region of the spectrum. In the order of decreasing their strength, these are 4.3-, 3.4-, 2.7- and 2.3-summer rhythms. The dragonfly population is well-coordinated with changes of both the weather and hydrological conditions that are important for it. The dynamics of its density is in agreement with perennial precipitation fluctuations, as well as with changes in the surface area size of Lake Chany. Even external influences, of which the course is not synchronous with density fluctuations, may have harmonic components that could be adjustable for corresponding rhythms of the dragonfly.
KEY WORDS: four-spotty dragonfly, population fluctuations, range of rhythms, recurrence of number, external synchronizer.