A female Argyrodes trigonum (Theridiidae) was observed feeding on a female Linyphia triangularis (Linyphiidae), a recently established European immigrant in Maine. Multiple observations of Argyrodes spiders inhabiting L. triangularis webs suggest that this invasive sheet-web weaver is not immune to web invasions, kleptoparasitism or predation by A. trigonum. The potential impacts of A. trigonum on the invasion dynamics of L. triangularis are unknown, but likely to be minimal.