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Author: Ittai Warburg

Abstract

Messor arenarius (Fabricius) is a harvester ant species, which is mainly distributed in deserts of the Middle East and North Africa. Ants of this species dig their nests in loess or sandy soils. In Israel, this ants’ species is distributed in the Negev Desert and in sandy soils along the Mediterranean Coastal Plain. In this work, 12 sites of natural habitats in the Northern Coastal Plain of Israel were surveyed for surface activity of M. arenarius ants. These ants were found in 3 out of these 12 natural habitats. Two of these sites where M. arenarius ants were found were subjected to disturbance, caused by development works during the period of this survey. It is concluded, that the populations of M. arenarius in the Northern Mediterranean Coastal Plain of Israel are endangered. It is also concluded, that the presence of either Artemisia monosperma or Retama raetam bushes in certain habitats in the Northern Coastal Plain of Israel, are not necessary or sufficient conditions for presence of M. arenarius in these same habitats.

In: Israel Journal of Ecology and Evolution
Author: Ittai Warburg

Abstract

According to central-place-foraging theory, selectivity of central-place foragers to larger or more profitable food items should increase as the distance from their nest to the food increases. In this research it was checked, if the selectivity of ants of the species Messor arenarius (Fabricius) to larger food items increases as a function of the distance from their nest entrance to the food site. In food choice experiments, whole wheat seeds and halves of wheat seeds cut longitudinally were offered to M. arenarius ants at the same points. These ants preferred halves of wheat seeds cut longitudinally over whole wheat seeds, in all the distances from nest entrance that were checked in this research - 1m, 5m or 10m from nest entrance. According to these findings, M. arenarius ants did not show increased selectivity to different wheat particles within a distance range of 1m – 10m from their nest entrance. It is possible that since the nutritional value of wheat is relatively high, these ants could not evaluate the nutritional value of wheat particles that were offered to them.

In: Israel Journal of Ecology and Evolution
Author: ITTAI WARBURG

Ants of the species Messor arenarius are individual foragers. This work deals with their collection patterns during foraging. Wheat seeds were spread in different spatial dispersions, ants were marked, and collections were recorded. In experiments with circular food sites it was found that the average angle between the first collections by the same ant in two consecutive experiments was significantly smaller than expected if these first seed collections were done in random directions, indicating that these ants have directional fidelity. In experiments with square food sites, it was found that the distances between two consecutive collections of the same ant were significantly smaller than expected if the collections were done randomly, indicating that these ants have patch fidelity. It is suggested that directional fidelity and patch fidelity are general phenomena among ants.

In: Israel Journal of Ecology and Evolution