Evidence for displacement of a North American spider, Steatoda borealis (Hentz), by the European species S. bipunctata (Linnaeus) (Araneae: Theridiidae)

Abstract

The European spider Steatoda bipunctata has apparently been introduced into North America through human transport. The earliest American collections were made in Nova Scotia in 1913. Until about 1933, specimens were known only on the coast of the Atlantic provinces, Maine, and along the St. Lawrence River and Lake Ontario, but they are now found widely in the Atlantic Provinces, northernmost New England, and southern Québec and Ontario. Habitats include buildings, bridges, piles of lumber and firewood, and crevices on tree trunks or among rocks. Evidence indicates that S. bipunctata, which closely resembles the native S. borealis in size, colour, microhabitat, diel activity, prey selection and utilization, life history, and sexual behaviour, can displace S. borealis. Displacement is, however, only partial, as S. borealis persists in forest habitats, where human influence is minimal. Laboratory tests on reproductive potential and interspecific aggression failed to demonstrate the method by which displacement takes place.

Evidence for the displacement of an endemic New Zealand spider,Latrodectus katipoPowell by the South African speciesSteatoda capensisHann (Araneae: Theridiidae)

“…Alternatively, Brown (1981) concluded there was inferential evidence of interspecific competition among orb weavers and Spiller (1984) found interspecific competition between spiders was significant and appeared to play an important role in structuring their community. Nyffeler et al (1986), in a study similar to the present one, concluded that competition was occurring between Steatoda bipunctata (Linnaeus) a European immigrant into North America, and S.…”

“…The two species are the same size, show a high level of microhabitat and diel activity overlap, and both select the same prey species at the same rate (Nyffeler et al 1986). Although Nyffeler et al (1986) felt that displacement was occurring they were unable to identify the mechanism by which it was operating. S.…”

“…borealis(the displaced species) actually appeared to be more likely to win an agonistic interaction with S. bipunctata in screen-cage laboratory experiments and S. bipunctata appeared to have no advantages in its reproductive potential or seasonal life history (Nyffeler et al 1986). Spiller (1984) suggestspredators or abioticfactors of mortality may have reduced spider abundance in some of theabove studies, thusreducing competition.…”

Structure and habitat use in a web‐building spider community in northern Italy

“…Other evidence for competition comes from cases of geographical displacement of a local species by an immigrant (Nyffeler et al, 1986), and of character displacement in sympatry (Toft, 1980). Competition by both interference and exploitation was found between some Araneidae species (Spiller, 1984).…”

Regional patterns in the invasion success of Cheiracanthium spiders (Miturgidae) in vineyard ecosystems

“…The negative impacts of invasive ant species, for example, have been enormous (Holway et al 2002). As generalist arthropod predators, spiders have the potential to affect native arthropod species; nevertheless, spiders have been largely overlooked as invasive species (but see Nyffeler et al 1986;Hann 1990;Burger et al 2001;Gruner 2005). Once established, invasive spiders may be viewed as either beneficial arthropods in agroecosystems, or as disruptive predators in native ecosystems.…”