Phylogeny and ecological traits of the spider Argiope trifasciata (Araneidae) in Egypt clarifying the relationships with Afro-Eurasian and American populations

Abstract

The orb-weaving spider Argiope trifasciata (Forsskål, 1775) was scientifically described in Egypt while it has been considered native to North America. The aim of this study was to analyse the phylogenetic relationships of the Egyptian population and shed light on its introduction and migration history. The COX1 gene (mtDNA) of 49 samples from Egypt and Cyprus was analysed with 168 additional COX1 sequences available in GenBank and BOLD originating from nineteen other countries. Selected ecological parameters were also studied in an Egyptian desert habitat for comparison with North American populations. We found that spiders oriented their webs in relation to the sun’s position (South and South-East) most likely to regulate their body temperature. The life cycle of A. fasciata in Egypt was found to be extended from what has been reported from other populations, partly possible because some individuals may survive throughout the winter. The phylogenetic analysis revealed that the sequences from Egypt and Cyprus clustered with Afro-Eurasian populations. Thirty haplotypes were found in Egypt and Cyprus of which 21 were unique. The analysis further revealed that the nearest American COX1 sequence was separated by 18 mutations. The high COXI divergence (5.1%) as well as the low gene flow (Fst = 0.75) between Afro-Eurasian and American populations, indicated that A. trifasciata has not been recently dispersed from America to Africa and other continents, but the genetic isolation was estimated to have happened around 2.04 My ago. If these spiders represent unique species or subspecies will need further research.