SEASONAL PATTERNS OF DEVELOPMENT OF FREE-LIVING INSECTS OF SEED PLANTS OF THE KARAKUM DESERT

Fifty types of annual developmental cycles have been defined among phytophagous free- and semifree-living insects of the Karakum desert. Cycles with winter, winter and summer, uninterrupted summer-winter, and summer resting stages are characteristic of 49, 16, 33, and 2 insect species respectively. Polyvoltine species constitute 28%, whereas bivoltine - 18%, and monovoltine - 54% of the fauna. Species with polyannual cycles were not found. Polyvoltine species dominate among insects with winter resting stages (58%), whereas those with summer-winter resting stages are primarily monovoltine (78%). Annual cycles with winter resting stages are characteristic of insects with stable food resources year-round of during the warm season. These are polyphagous species, or those inhabiting trees and polyannual grasses with long vegetation periods). Summer-winter resting species are connected with ephemeral or ephemeroid plants, grasses with medium vegetation periods, and with generative structures. Estivation without a winter resting stage is characteristic of psychrophilic copeognathes, microphytophagues (Mesopsocus, Hemineura), and certain lepidopterans (Cheimoptena, Imitator). Winter resting stages are usually incompletely grown larvae (31%) and eggs (32%). Summer-winter resting ones are mainly imago (44%) and eggs (41%). Recent seasonal cycles of Karakum insects originated in the second half of Pliocene. Among them the primary ones are those with winter delay in development. Most similar to them are polyvoltine cycles with hibernating incompletely grown active larvae at different stages (Adelungini). Seasonal cycles with summer-winter, summer, and winter resting stage with resumption of autumn development are derived from the cycle with a winter resting stage. They became widely spread in the second half of Quaternary and in Holocene. This was connected with the regression of the hydrographical net and the drying of Turan deserts, as well as with subsequent ephemerisation of vegetation, further increase in the continentality of the climate, and deterioration of the summer period ecological conditions.