Spatial Distribution of Lepidoptera in Forest Ecosystems of Central European Russia: Studies Using Beer Traps

Abstract

Temperate forests are highly complex ecosystems in which many aspects of invertebrate distribution and abundance remain poorly understood. In order to accumulate data on the vertical and temporal distribution of forest Lepidoptera in the Republic of Mordovia (central European part of Russia), specimens were collected with beer-baited traps from April to October in 2019–2022. Traps were deployed at different heights above ground level (i.e., 1,5, 3,5, 7, and 12 m) in deciduous forests, pine forests, forest edges, and forest glades. Over the four-year sampling period, over 69,000 specimens of Lepidoptera were collected and examined. In deciduous forests, maximum abundance was observed at 12 m above ground level, whereas in pine forests, maximum abundance was observed at 7 m. In both forest types, the lowest abundance was observed at the lowest sample sites (i.e., 1.5 m above ground level). In forest glades in 2020, maximum abundance was observed at 2 m, with abundance showing a conspicuous decline with trap height above the ground. However, this pattern was not repeated in subsequent years. Lepidoptera exhibited various patterns of seasonal abundance among habitat types, but most showed bi- or trimodal patterns (corresponding with spring summer and fall), with the greatest number of specimens captured in late summer or autumn. Forest edges showed the greatest abundance of all sampled habitat types.