The dietary basis for temporal partitioning: food habits of coexisting Acomys species |
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Authors: | Noga Kronfeld-Schor Tamar Dayan |
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Institution: | (1) Department of Zoology, Tel Aviv University, Tel Aviv 69978, Israel, IL |
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Abstract: | Two rodent species of the genus Acomys coexist on rocky terrain in the southern deserts of Israel. The common spiny mouse (A. cahirinus) is nocturnally active whereas the golden spiny mouse (A. russatus) is diurnally active. An early removal study suggested that competition accounts for this pattern of temporal partitioning:
the golden spiny mouse is forced into diurnal activity by its congener. Theoretically, temporal segregation should facilitate
coexistence if the shared limiting resources differ at different times (primarily among predators whose prey populations have
activity rhythms), or if they are renewed within the period of the temporal segregation. We studied food preferences of the
two Acomys species in a controlled cafeteria experiment in order to assess resource overlap and the potential for competition for food
between the two species. We found no significant difference in food preferences between species. The dietary items preferred
by both were arthropods. We also carried out a seasonal study of the percentage and identity of arthropods taken in the field
by individuals of the two species. Individuals of both species took on annual average a high percentage of arthropods in their
diets. Seasonal diet shifts reflect seasonal abundance of arthropods at Ein Gedi during day and night. Diurnal activity may
also reduce interspecific interference competition between A. russatus and A. cahirinus. However, the strong interspecific dietary overlap in food preference, the heavy reliance on arthropods in spiny mouse diets,
and the seasonal and circadian differences in arthropod consumption suggest that prey partitioning may be a viable mechanism
of coexistence in this system.
Received: 6 July 1998 / Accepted: 10 May 1999 |
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Keywords: | Acomys Interference competition Food habits Temporal partitioning Resource partitioning |
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