caa a22 4500 386361797 CHVBK 20180307111918.0 cr unu---uuuuu 161130e198911 xx s 000 0 eng 10.4039/Ent121941-11 doi S0008347X00035847 pii (NATIONALLICENCE)cambridge-10.4039/Ent121941-11 SPATIAL-TEMPORAL VARIABILITY AND THE STUDY OF AQUATIC INSECTS [Elektronische Daten] Spatial and temporal variability are essential considerations in the study of aquatic insects. Traditionally, these two sources of variability are treated separately; however, they should be considered together because they occur concurrently in natural systems. To illustrate this interaction, we constructed two-way variability tables in which spatial (habitat, reach or zone, system, intersystem) and temporal (within a day, within a season, within a year, year to year) scales were ordered on separate axes, and examples of concurrent spatial and temporal variability were entered at the intersects of the scales. We examined three aspects of aquatic insect life histories in lotic and lentic waters using such tables: emergence, feeding and growth, and movements and migrations. It proved easier to find examples for the stream tables than for the lake tables, perhaps because of greater spatial and temporal variability in lotic than lentic waters. Also, more papers have been published on stream than on lake insects over the last decade or so. Spatial and temporal scales at which lotic and lentic research is done were determined by examining the recent contents of five key aquatic journals (≈ 500 articles). Research on aquatic insects appears generally to be done at relatively long temporal scales, but at smaller spatial and shorter temporal scales in lotic than lentic systems. Perusal of the literature to find examples of concurrent spatial and temporal variability revealed the prevalence of a "mean-values” appproach to data analysis, in which investigators "homogenize” data to reduce spatial and temporal variability. However, it is this spatial and temporal variability that often provides an explanation of factors causing the patterns observed. A "variance” approach, in which data are disaggregated and fluctuations or extremes are considered, may be far more informative and may elucidate underlying mechanisms. Copyright © Entomological Society of Canada 1989 Resh Vincent H. Department of Entomological Sciences, University of California, Berkeley, California, USA 94720 Rosenberg David M. Department of Fisheries and Oceans, 501 University Crescent, Winnipeg, Manitoba, Canada R3T 2N6 The Canadian Entomologist Cambridge University Press 121/11(1989-11), 941-963 0008-347X 121:11<941 1989 121 TCE https://doi.org/10.4039/Ent121941-11 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.4039/Ent121941-11 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Resh Vincent H. Department of Entomological Sciences, University of California, Berkeley, California, USA 94720 NATIONALLICENCE 700 1- Rosenberg David M. Department of Fisheries and Oceans, 501 University Crescent, Winnipeg, Manitoba, Canada R3T 2N6 NATIONALLICENCE 773 0- The Canadian Entomologist Cambridge University Press 121/11(1989-11), 941-963 0008-347X 121:11<941 1989 121 TCE CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge