Apple snail egg perivitellin coloration, as a taxonomic character for invasive Pomacea maculata and P. canaliculata, determined by a simple method

PASQUEVICH, M. Y.; HERAS, H.

BIOLOGICAL INVASIONS

SPRINGER

Año: 2020 vol. 22 p. 2299 - 2307

1387-3547

Pomacea canaliculata and Pomacea maculata are freshwater apple snails considered two of the most invasive alien species worldwide. They are expanding in Asia, Europe and North America damaging crops, wetland ecosystems and endangering human health. Despite having different invasive potential, they have systematically been misidentified due to their morphological plasticity with highly variable shells, hampering efforts to manage their spread and impact. Rapid species identification in new invaded areas is critical and currently the laborious analyses of genetic markers are the only unambiguous method to distinguish them. Here we report a faster, simple and inexpensive assay to unequivocally differentiate these species based on the spectroscopic characteristics of their pigmented egg proteins. The egg perivitelline fluid is analyzed in a conventional agarose gel electrophoresis and the naturally-colored carotenoprotein are extracted without the need of staining and analyzed spectrophotometrically. Then the ratio between two wavelengths of the absorbance spectra unequivocally differentiates them. Results can be obtained in less than 24 h. Field validation was attained by the analyses of seven populations from Asia (non-native) and America (native) genetically identified by the cytochrome c oxidase subunit 1 (COI) gene sequences. The method has the added advantage that eggs are oviposited in conspicuous masses above the waterline, allowing rapid detection and easy collection in the field.