spiders (Trechaleidae) from southern Mexico: DNA barcoding, venomics, and biological effect.

BACKGROUND

Members of the genus Simon, 1891 are categorized as wandering spiders and are part of the family Trechaleidae. The genomics and proteomics of spiders from North America remain uncharacterized. The present study explores for the first time molecular data from the endemic species Medina, 2006, and also presents new data for (Keyserling, 1878), both collected in southern Mexico.

METHODS

In total, 88 specimens were collected from southern Mexico and morphologically identified. DNA was extracted and the mitochondrial COI fragment was amplified. COI sequences were analyzed, and a phylogenetic tree was inferred for species from the Americas. Genetic diversity was analyzed using haplotype networks and gene distances. Venom was obtained from and by electrostimulation. The venom was separated by HPLC, visualized using SDS-PAGE, and quantified for use in toxicity bioassays in mice and insects.

RESULTS

Analysis of COI sequences from showed 94% identity with , while exhibited 94-97% identity with sequences from Central and South American conspecifics. The venom from exhibited toxic activity against crickets. Venoms from and caused death in flies. Analysis of venom fractions from and revealed molecular masses of a similar size as some previously reported toxins and neurotoxic components. We determined the amino acid sequences of ChiaTx1 and ChiaTx2, toxins that are reported here for the first time and which showed toxicity against mice and insects.

CONCLUSION

Our work is the first to report COI-based DNA barcoding sequences from southern Mexican spiders. Compounds with toxic activity were identified in venom from both species.