Introduced pholcids on Galapagos: a threat for native species?
Published in Arachnology, 2022; https://doi.org/10.13156/arac.2022.19.sp1.191

Several species of Pholcidae have followed humans to other continents or around the world. Negative impacts of these species on the local faunas have never been reported. Here we present results of a short collecting trip to Galápagos in 2019, focusing on two species that have been introduced to the archipelago by humans and whose spread appears correlated if not causally linked to the decline or disappearance of two native species occupying the same microhabitats: (1) The local abundance of the introduced Modisimus culicinus (Simon, 1893) appears negatively correlated with the abundance of the native Galapa bella (Gertsch & Peck, 1992). (2) The recently introduced Smeringopus pallidus (Blackwall, 1858) is now abundant in caves where a few decades ago the native and strongly troglomorphic Aymaria jarmila (Gertsch & Peck, 1992) was present. The latter species was not found in any of the six caves visited on Santa Cruz Island in 2019, suggesting that it may be seriously threatened. Top: Modisimus culicinus (left) appears to displace Galapa bella (right). Bottom: Smeringopus pallidus (left) seems to have replaced Aymaria jarmila (right.)