The results suggest an important role of both ant species in the grassland food web, strongly affecting the densities of decomposers, herbivores and higher trophic levels. Ant nest soil on its own did not have a significant impact on densities of decomposers, herbivores or predators, which were significantly, and positively, affected by the addition of an intact nest.ħ. To test whether the positive ecosystem engineering effects were purely caused by modified properties of the soil, we added in an additional experiment (i) the soil from ant nests (without ants) or (ii) unmodified soil or (iii) ant nests (including ants) to experimental plots. This effect was independent of ant colony density, but where two colonies were present, spider richness was significantly greater in plots with two M. rubra colonies than in plots with one colony of each ant species.Ħ.

Spider density was not affected by ant colony manipulation, but species richness of spiders responded positively to ant presence. Generally, effects of the two ant species were similar with the exception of their effect on Braconidae parasitoid densities that responded positively to one colony of M. rubra but not of L. niger.ĥ. However, in the case of herbivores and parasitoids, this effect was reversed in the presence of two colonies.Ĥ. Frank- being calm and acceptant of the situation Dussel- Ignores Peter's attempted comfort and goes to his room Mrs. the hard decision if you should upvote so that 6.9 becomes 7.0 or if you should keep it at that. The experiment revealed a positive influence of the presence of one ant colony on densities of decomposers, herbivores and parasitoids. Franktheant 1 point 2 points 3 points 2 years ago. Colony presence and density of these two ant species were manipulated in a field experiment from the start of ant activity in spring to late summer.ģ. We studied the impact of two ant species common in Central Europe, Myrmica rubra and Lasius niger, on an arthropod community. They are likely to influence any other terrestrial arthropod group either directly or indirectly caused by their high abundance and territoriality.Ģ. Ants are ubiquitous ecosystem engineers and generalist predators and are able to affect ecological communities via both pathways.

Frank the ant 2