The stability of vertical distribution profiles of insects in air layers near the ground

The vertical distribution of insect orders, families, and species captured over 10 elevations from the ground to 15 m over 4 years in a potato agro-ec osystem differed considerably within and between taxa. Regression slopes re presenting these aerial profiles remained similar over the 4 years of the s tudy for orders Thysanoptera, Neuroptera, and Psocoptera, changed considera bly for Hemiptera, Homoptera and Ephemeroptera, and were statistically non- homogeneous for Coleoptera, Hymenoptera, Diptera, Lepidoptera, Trichoptera, and Plecoptera. The slopes of the aerial profiles for families remained si milar over the years for Carabidae and Elateridae, changed for Staphylinida e, Meloidae, and Scarabeidae, but were statistically non-homogeneous for Co ccinellidae, Miridae, and Aphididae. The slopes of the aerial profiles for insect species were similar across years for Coccinella septempunctata L., Melanotus similis (Kirby), and Anatis mali Say, changed for Pyrrhalta luteo la (Mull.), Ctenicera pulchra LeConte, Ctenicera tarsalis Melsheimer, Cocci nella trifasciata perplexa Muls., Lygus lineolaris (P. de B.), Ctenicera ap propinquans Randall, Apis mellifera L., and Adalia bipunctata (L.), but wer e significantly non-homogeneous only for Hippodamia convergens G.-M. Althou gh most profiles obtained for insect orders in this study were remarkably s imilar to those reported in the literature, the level of between-year varia tion at our study site suggests that there is considerable overlap between profiles at all taxon levels. Vertical aerial profiles cannot be considered sufficiently characteristic of the species, family, or order across years for use as indicators of change in biodiversity. The impact of these result s on insect monitoring are discussed.