engleski

Exploratory use of geometric morphometrics in the identification of wireworm species

Wireworms are click beetle larvae from the genus Agriotes (Coleoptera: Elateridae) that cause considerable damage to field crops. Five of the 18 Agriotes species recorded in Central Europe are found in arable land in continental Croatia and can cause significant economic yield losses. The identification of these larvae to the species level are difficult or impossible using classical taxonomic measurements. Our study explores the use of species-specific morphological characters (i.e. specific spiracles placed on the ninth abdominal segment, certain structures of the mandible...) that will enable the use of geometric morphometric methods for diagnostic purposes. Geometric morphometrics is the quantitative measurement, analysis and interpretation of shape variation in organisms. The application of GM in taxonomy and systematic is novel and has the potential to provide information on shape variation through the relative position of homologous landmarks. GM has been previously used in WCR population analyses, Bactrocera dorsalis species complex, Tortricidae and Geometridae species analyses and other important agricultural insect pests. The aim of this study was to explore the use of landmark-based morphometric analyses as a simple method to discriminate among species in mixed wireworms populations. Approximately 10 homologues landmarks were used in species discrimination of five Agriotes species including A. sputator, A. lineatus, A. brevis, A. obscurus, A. ustulatus randomly collected on arable land across Croatia. Each landmark was digitised and imported in MorphoJ software for further statistical analyses. Statistical procedures used in this study were: Generalized Procrustes Analyses, Discriminant Function Analyses, Principal Component Analyses and Canonical Variates Analyses. Morphometric results will be verified by polymerase chain reaction (PCR) analyses of Agriotes species using diagnostics primers published by Staudacher et al. (2010). We demonstrate that GM techniques hold promise as a diagnostic tool for discriminating between morphologically cryptic taxa of the Agriotes species complex.

wireworms; geometric morphometric; species identification

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