Arthropods (Jun 2020)
Heuristic, parsimony and molecular analysis of variations between selected orb-weaver spiders from Mindanao, Philippines
Abstract
Morphological structures and phenotypic characteristics define the status of organisms. It serves as their landmark for easy identification. Samples of orb-weaving spiders were surveyed in selected areas in Mindanao, Philippines, to describe the extent of morphological variations in body structures. Aside from their colorful and spiny abdomen, characters other than generally used to describe species were explored to be able to find specific landmarks to determine these spiders identity. These characters were also used in comparing the described variationsbetween species using a heuristic method and parsimony analysis. DNA barcoding analysis using mitochondrial DNACOI sequences was also used to strengthen species delineation. Qualitative and quantitative morphological descriptions of body parts of the collected orb-weaver spiders showed a total of 7 species: 2 species under the genus Thelacantha, one species is under the genus Cyrtarachne, and four species were under the Gasteracantha genus. Thelacantha brevispina originally described as G. mammosa has shown features that are remarkably different from two other species G. janopol, and G. diadesmia based on the number and color of sigilla, including the sternum and color of the abdomen. Parsimony analysis of the morphological characters shows two separate groups of spiders showing homologous and analogous characters that are present on different species from their nodes. Results of the DNA barcoding revealed that Gasteracantha and Thelacantha orb-weaving spiders are not taxonomically close. The results of this study imply that the classification of organisms must include not only using morphological features but should also use other tools such as DNA barcoding to be able to have a clearer understanding of both phenotypic and molecular differentiation between species.
