EMIGRATIONS AND ANTI-PREDATOR BEHAVIOR IN THE ANT GENUS PHEIDOLE.
Item
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Title
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EMIGRATIONS AND ANTI-PREDATOR BEHAVIOR IN THE ANT GENUS PHEIDOLE.
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Identifier
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AAI8319813
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identifier
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8319813
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Creator
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DROUAL, ROBERT.
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Contributor
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Kumar Krishna | Carol Simon
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Date
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1983
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Entomology
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Abstract
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The ants Pheidole desertorum and P. hyatti emigrate approximately twice a month. Although both species emigrate to freshly excavated nests, they also frequently return to old nests. This, and the varied directions in which the emigrations occur, result in the colony remaining within the same foraging area.;Both Pheidole species are also heavily preyed upon by the army ant Neivamyrmex nigrescens against which they use similar nest-evacuation defenses. These defenses possess properties that reduce the disorder inherent in nest evacuation. The defenses occur in two phases. In the "alert" phase the colony masses around the nest entrance in preparation for an evacuation. In the "evacuation" phase the colony runs from the nest. When the ants run from the nest they follow their own chemical foraging trails. In both species a high proportion of the major worker subcaste evacuate brood. However, a significantly greater proportion of P. hyatti majors engage the army ants in combat. This difference is related to differences between the species in their nest structure, and the combat ability and running speed of their workers, that make P. hyatti's evacuations slower than P. desertorum's. The enemy specificity of the nest-evacuation defense of both species is suggested by the absence of nest evacuation against some species of Neivamyrmex.;The relationship between emigrations and the nest-evacuation defense was investigated in P. desertorum. The emigrations result in the colony having multiple nests of which only one is occupied at a time. However, after an evacuation, the colony settles into all its nests. If no further army ant raids occur, the colony eventually reunites again in one nest. A field procedure demonstrated that all nests are quickly found and used by the Pheidole ants after an evacuation. In a field experiment it was found that the brood and alate survival in colonies that had access to all their nests after an evacuation was significantly greater then in colonies denied access to all nests except the one they evacuated. This suggests that the emigrations function to increase the effectiveness of the nest-evacuation defense.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
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Program
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Biology
