Spiders in the Galapagos

A researcher from the Charles Darwin Research Station plots the success of spider evolution on the islands

Borne on flotsam or carried by the wind, a surprising number of spiders made it over time to the Galápagos Islands. The fauna was largely overlooked until the 1980s when Belgian-born Leon Baert began his 20-year research resulting in a list of 114 spider species in 31 families. Now Germania Estévez, the Associate Curator of Terrestrial Invertebrates at the Darwin Station, is visiting Academy arachnologist Charles Griswold to hone her skills in spider taxonomy so she can focus on a new challenge: to learn the systematics of the Galápagos spiders.

One group of spiders (Tetragnathidae) known from Ecuador's rain forests interests Estévez: colony-forming orb weavers. Thus far they have not been found in the Galapagos, but Estévez has targeted the Miconia-rich shrubs of Cerro Crocker area of Santa Cruz Island (620-860 m elev.) as their likeliest habitat. Due to introductions of invasive Cascarilla trees (Cinchona pubescens) that are destroying the Miconia robinsoniana habitat, Estévez' recent trappings in Cerro Crocker has resulted in lower numbers of spider species overall--from 8 families Baert found in the 1980s to only 2 in 2001.

Armed with new insights in spider taxonomy gained from her internship at the Academy, Estévez hopes to find the elusive orb weavers in her 2003 field season. In any case, the eventual result of all her research will be a new web-accessible Key to the Spiders of the Galápagos Islands (with images), and a better understanding of current habitat quality on Santa Cruz for future conservation management plans.

Map by Colleen Sudekum