TY - JOUR
T1 - Annual foraging of the leaf-cutting ant Atta colombica in a semideciduous rain forest in Panama
AU - Wirth, Rainer
AU - Beyschlag, Wolfram
AU - Ryel, Ronald J.
AU - Hölldobler, Bert
N1 - Funding Information:
We should like to thank the Smithsonian Tropical Research Institute (STRI) for allowing us to use the Barro Colorado Island facilities and Drs. E. Leigh, S. J. Wright (both STRI), and F. Roces (University of WUrzburg) for their general support and for sharing their experience with us. Dr. Roces and Dr. J. J. Howard (University of New Orleans) are also thanked for their critical reading of and their helpful comments on the first draft of this manuscript. We are also grateful for the valuable suggestions of three anonymous reviewers and of the editor Dr. D. M. Newbery. Mr. E. Sierra and Mr. R. Perez (both STRI) helped us with plant identification. We further acknowledge the invaluable help of the following student workers from Germany and Panama: J. Berger, Q. D. Fuenmayor, H. Herz, M. Rodriguez, S. Rottenberger, G. Schmidt and A. Weigelt. This research has been funded by the Deutsche Forschungsge-meinschaft, Bonn (SFB 251, University of Wiirzburg). The results are part of the Ph.D. Dissertation by R. Wirth.
PY - 1997/9
Y1 - 1997/9
N2 - In a 1-y study of vegetation harvested by the leaf-cutting ants, Atta colombica Guerin, daily harvesting activity of two nests was observed for 24 h at c. 1-wk intervals (colony I: June 1993-June 1994; colony II: February-June 1994) on Burro Colorado Island. The average daily quantity of green leaves harvested by colony I was higher during the wet season (11.4 m2 d-1) than during the dry season (9.0 m2d-1), but was highly variable between survey days. Total annual herbivory of green leaves was estimated to be 3,855 m2 foliage area for colony I and 1,707 m2 for colony II. Total dry weight of biomass harvested was higher in the dry season because most material collected during the wet season consisted of green leaves, while during the dry season, more than 50% of the total collected biomass was non-green plant material (stipules of Ficus sp., fruits, seeds, and flower parts of a variety of other species) which represented c. one third (111 kg y-1) of the total annual intake (370 kg y-1) of plant material. Total daily biomass intake was negatively correlated with daytime rainfall. The peak of daily foraging was affected by timing and duration of rainfall events. Highest input rates normally occurred between 15:00 and 16:00 h (colony I). Dry weight and surface area of harvested leaf fragments differed between plant species, with thicker leaves generally being cut into smaller pieces. Significant linear correlations were found between total daily harvest of fragments and the respective harvesting rate at the maximum of daily activity. High correspondence was found between estimates using this relationship and the measured daily leaf harvest of four other Atta colonies and of two colonies reported in published literature. The use of this relationship as a research tool is discussed.
AB - In a 1-y study of vegetation harvested by the leaf-cutting ants, Atta colombica Guerin, daily harvesting activity of two nests was observed for 24 h at c. 1-wk intervals (colony I: June 1993-June 1994; colony II: February-June 1994) on Burro Colorado Island. The average daily quantity of green leaves harvested by colony I was higher during the wet season (11.4 m2 d-1) than during the dry season (9.0 m2d-1), but was highly variable between survey days. Total annual herbivory of green leaves was estimated to be 3,855 m2 foliage area for colony I and 1,707 m2 for colony II. Total dry weight of biomass harvested was higher in the dry season because most material collected during the wet season consisted of green leaves, while during the dry season, more than 50% of the total collected biomass was non-green plant material (stipules of Ficus sp., fruits, seeds, and flower parts of a variety of other species) which represented c. one third (111 kg y-1) of the total annual intake (370 kg y-1) of plant material. Total daily biomass intake was negatively correlated with daytime rainfall. The peak of daily foraging was affected by timing and duration of rainfall events. Highest input rates normally occurred between 15:00 and 16:00 h (colony I). Dry weight and surface area of harvested leaf fragments differed between plant species, with thicker leaves generally being cut into smaller pieces. Significant linear correlations were found between total daily harvest of fragments and the respective harvesting rate at the maximum of daily activity. High correspondence was found between estimates using this relationship and the measured daily leaf harvest of four other Atta colonies and of two colonies reported in published literature. The use of this relationship as a research tool is discussed.
KW - Atta colombica
KW - Foraging patterns
KW - Herbivory
KW - Leaf-cutting ants
KW - Tropical rain forest
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U2 - 10.1017/S0266467400010907
DO - 10.1017/S0266467400010907
M3 - Article
AN - SCOPUS:0030817533
SN - 0266-4674
VL - 13
SP - 741
EP - 757
JO - Journal of Tropical Ecology
JF - Journal of Tropical Ecology
IS - 5
ER -