A NOVEL APPLICATION OF FACTOR ANALYSIS TO EXAMINE INTERACTIONS OF THE FOSSORIAL PREDATORS Sirthenia striata (HEMIPTERA : REDUVIDAE ) AND Megacephala fulgida (COLEOPTERA : CICINDELIDAE)

Harold Gordon FOWLER[1]

§    ABSTRACT: A method is proposed for two-species field abundance data having a high variance and/or low levels of correlation. Sample region distributions of each species are characterized, and then combined into bivariate scatter diagrams for normalization. Normalized data are then ordinated by factor analysis for interpretation. The method is used to examine species-environment relationships of the common riverine fossorial insect predators, Sirthenia striata (Reduviidae) and Megacephala fulgida (Cicindelidae) . S. striata is interpreted as being favored in smaller sand banks and having a poor dispersal capability, while M. fulgida disperses rapidly and is relatively more abundant in deeper sand banks. This method can be used in examination of species-environment relationships for other noisy data sets.

§    KEYWORDS: Distribution; data normalization; factor analysis.

 



[1]Departamento de Ecologia - Instituto de Biociências - UNESP - 13506-900 - Rio Claro - SP.