Niche Differentiation of Ant Species within Territories of the Wood Ant Formica polyctena

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. . Wiley-Blackwell and Nordic Society Oikos are collaborating with JSTOR to digitize, preserve and extend access to Oikos. Savolainen, R. and Vepsalainen, K. 1989. Niche differentiation of ant species within territories of the wood ant Formica polyctena. -Oikos 56: 3-16.The question if dominant ant species affect habitat use of other ant species was studied around two mounds of the territorial Formica polyctena. We sampled foraging ants at 10, 30 and 60 m from the mounds in four vertical layers on rocky outcrop interspersed with small vegetation patches and in neighbouring forest. We tested expected interactions among ant species on the basis of a linear competition hierarchy concept consisting of three levels: territorial (top competitors), encounter (aggressive but nonterritorial) and submissive (nonaggressive) species. We focussed on resource partitioning by space (not by food) and shifts in use of vertical layers of the habitat in presence of the territorial species. F polyctena was present everywhere except in the litter. Its numbers decreased with distance from its mound, although its activity was substantially patchy within each distance zone. The encounter species occurred occasionally in places where F. polyctena was scarce. The submissive F. fusca, morphologically similar to the top dominant, did not respond by layer shifts; but its numbers decreased toward the mound of F polyctena. The submissive Myrmica shifted from surface of ground to litter and shrub layers at high densities of the dominant. Small colonies and short foraging distances of the submissive species allow coexistence within the territory in lowdensity patches of F polyctena. Our ant community consists of three functional guilds corresponding to taxonomic and morphological guilds: the larger above-ground Formicinae, the smaller and compacter Formicinae, and the small litter-inhabiting Myrmicinae. Interference competition is stronger and more effective among the Formicinae than among the Myrmicinae or between the subfamilies, but the top dominant affects all ant species of the community. Coexistence between the submissives and the top dominant is facilitated by niche differentiation and behavioural responses in the presence of the top dominant.

Explosive food recruitment as a competitive strategy in the ant Myrmica sabuleti (Hymenoptera, Formicidae)

“…The two Formica species were observed on the same plants (or tubes of sucrose solution) as those exploited by M. sabuleti. Temporal segregation ensures a partial decrease of competition between M. sabuleti and the two Formica species: the foragers of M. sabuleti avoid the warmer hours of the day, whereas the foragers of Formica are particularly active during these hours (see also Savolainen and Vepsäläinen, 1989;Deffernez et al, 1990). This temporal segregation was mainly observed in the experiments with sugar baits, whereas the frequency of M. sabuleti increased from morning to evening on the extrafloral nectaries of V. sativa.…”

“…and Vepsäläinen, 1989). Traniello (1983) suggested that "in the case of generalist, opportunistic ant species, partitioning may be behavioural, based at least in part on differences in social methods of foraging".…”

Interference by wood ant influences size selection and retrieval rate of prey by Formica fusca

“…Because of the small colony size (Savolainen 1990) and opportunistic foraging, colonies of F. fusca may survive within small patches of suitable habitat between the trunk trails of F. polyctena, where the average density of foraging F. polyctena individuals is low (Savolainen and Veps/il/iinen 1989). However, foragers of F. fusca are likely to encounter F. polyctena individuals.…”

“…A noncooperative two-nest system of F. polyctena studied closely in recent years has about one million foragers and territories extending at least 100 m from the mounds (Pisarski and Veps~ilfiinen 1989). Around the mound the foragers patrol at high densities up to 40 m off the mound, both in the open, exposed rocky outcrop and in the forest, and occupy all vertical layers above the litter (Savolainen and Veps/il/iinen 1989). Within the territories of F. polyctena the cryptic nests of F. (Serviformica) fusca may be found even 20 m from the wood-ant mounds.…”

Ants (Hymenoptera: Formicidae) of Chełmowa Góra in the Świętokrzyski National Park

“…F. polyctena and F. rufa), well-known for their restrictive impact on lower-ranked species (Mabelis 1984, Pisarski & Vepsalainen 1989, Savolainen & Vepsalainen 1989, Savolainen et al 1989, Punttila et al 1991. The community-structuring role of these species can be revealed, when ant communities with and without them are analyzed -as e.g.…”