Sympatry and allopatry in two desert ant sister species: how do Cataglyphis bicolor and XXXX coexist?

@entity2133 @entity10722 @entity61628
Two extremely morphologically similar sister species of desert ants, Cataglyphis bicolor and @entity61628 , exhibit broadly overlapping distributional ranges within Tunisia. In order to analyse the microhabitats of @entity10722 and @entity61628 within the sympatric and allopatric areas of both ant species, the plant species located at 113 different nest sites of the two ant species were determined. In the sympatric area, the two species exhibit a clear-cut nest site segregation. This is not the case in the allopatric areas. Hence the two species differentiate their microhabitat only when they are sympatric. The plant species associated mainly with the nest sites of @entity10722 indicate that this species prefers a type of vegetation that needs irrigation. This is in contrast to the nest sites of @entity61628 , which are usually found around plants that characterize typical @entity2133 . As the ants' foraging paths recorded in the sympatric area reveal, @entity10722 performs significantly shorter foraging runs with respect to both length and time, and covers a much smaller foraging range than @entity61628 does. This result reflects the fact that the microhabitat occupied by the colonies of @entity10722 is richer in food abundance. When direct interspecific interactions were investigated by placing a bait midway between two heterospecific nests, @entity10722 foragers dominated over those of @entity61628 . The same dominance of @entity10722 over @entity61628 occurred in laboratory experiments. These results suggest that the dominant species drives the subordinate one out of the high quality microhabitats, and that the subordinate species is forced to survive in the less lucrative habitats. In conclusion, coexistence seems to be maintained by the asymmetric competitive relationship between the two species and the fact that the subordinate species has the ability to endure in the less favourable microhabitat.
