Diversity and species composition of two different moth families (Lepidoptera: Arctiidae vs. Geometridae) along a successional gradient in the Ecuadorian Andes
- The diversity of two very species-rich families of arctiid and geometrid moths was investigated in a montane area in the Andes in southern Ecuador (Reserva Biológica San Francisco, 3°58´ S, 79°5´ W) along a succession gradient ranging from a barely vegetated landslide area to mature forest understorey between 1,800 and 2,005 m above sea level. This study was part of a larger interdisciplinary project on diversity and functioning of a tropical mountain rainforest ecosystem. Moths were collected during three field periods in the years 2002 (March to April, October to November) and 2003 (August to October) at the 15 succession sites. Moths were manually sampled by attraction to weak light sources (2 x 15 W tubes: black light and super-actinic light) in a white gauze cylinder from 18:45 to 21:45 h. Data from this study (15 succession sites) were compared with data from six natural forest understorey sites sampled in the years 1999 and 2000 in the same region. A total of 9,211 arctiid moths representing 287 species, of which 135 belong to the tribe Phaegopterini, followed by Ctenuchini/Euchromiini (82), Lithosiinae (54), Pericopini (9), and Arctiini (7), as well as 23,720 geometrid moths representing 868 species were recorded at 21 sites. Large proportions of the samples (Arctiidae: 70.4% of species, 76.1% of individuals; Geometridae: 65% of species, 78.1% of individuals) were identified to species level. The study deals with patterns of alpha- and beta-diversity, ensemble structure, wing colouration and various other morphological traits of arctiid moths along the succession gradient. In addition, temporal dynamics of moth ensembles as well as the role of environmental factors such as temperature or habitat openness as predictors of faunal change at small spatial scales were investigated.