The Effects of Seasonality on Foraging in Two Species of Leaf-Cutting Ants (Atta) in Guanacaste Province, Costa Rica

Rockwood, Larry L.

doi:10.2307/2989622

Cited by 71 publications

(77 citation statements)

References 13 publications

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“…Variation in the plant species preferred by leafcutting ant colonies has been reported for both Atta cephalotes and A. columbica (Rockwood 1976). Such variation may exist for a variety of reasons, including genetically determined differences in nutrient requirements or in the ability of ants or fungus to tolerate some secondary chemicals, physiological adaptation to different sec?…”

Section: Colony-to-colony Variation In Palatabilitymentioning

confidence: 98%

Leafcutting Ant Diet Selection: The Role of Nutrients, Water, and Secondary Chemistry

Howard¹

1987

Ecology

102

101

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The relationship of plant secondary chemistry, water content, and nutrient content to the palatability of leaves to the leafcutting ant Atta cephalotes was determined in a study of individuals from 50 woody plant species in tropical dry forest of Costa Rica. The study took place during the yearly period of maximum leaf harvest, in the early rainy season. The palatability of plants was determined by presenting leaf disks to ants on active foraging trails of three ant colonies. The distribution of several classes of polar secondary compounds in leaf samples was determined using chemical spot tests, and that of antdeterrent nonpolar compounds using laboratory bioassays of plant nonpolar extracts. Ni? trogen, energy, and water availability in leaves were assessed using quantitative analyses. Ecological Society of AmericaPlants of high relative palatability generally lacked deterrent nonpolar extracts but did contain hydrolyzable tannins; the opposite was true for plants of low palatability. Little or no relationship was found to exist between plant palatability and measures of leaf nitrogen, energy content, and moisture content, or the presence of alkaloids and condensed tannins in leaves. No statistically significant interactions among leaf characteristics were found. The number of leaf disks harvested by ant colonies decreased during the study period. This decrease was unrelated to nutrient and moisture availability in leaves, but may be related to changes in secondary chemistry over the course ofthe season. Although plants were not equally palatable to all colonies tested, there was no evidence that colony-to-colony dif? ferences in plant preferences were related to the plant characteristics studied. Overall, the results suggest that plant secondary chemistry is the best predictor of plant species utilization by leafcutting ants.

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Section: Colony-to-colony Variation In Palatabilitymentioning

confidence: 98%

Leafcutting Ant Diet Selection: The Role of Nutrients, Water, and Secondary Chemistry

Howard¹

1987

Ecology

102

101

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“…Adult ants subsist primarily on plant juices imbibed from cut and crushed leaf tissues, and use solid leaf material to culture a mutualistic fungus that provides digestive enzymes to adults and is the only food of larvae (Quinlan and Cherrett 1979). Leafcutters exhibit striking patterns of preference for plants and plant tissues (Cherrett 1968, Rockwood 1975, and physical characteristics of leaves are thought to influence these patterns. The preference of leafcutting ants for young leaves has often been attributed to the greater toughness of mature leaves (Fennah 1950, Cherrett 1972).…”

Section: Physical Features Of Plants Such As Trichomes and The Toughmentioning

confidence: 99%

Leafcutting and Diet Selection: Relative Influence of Leaf Chemistry and Physical Features

Howard

1988

Ecology

109

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The effects of leaf toughness, trichome characteristics, nutrient and water availability, and secondary chemistry on diet selection by the leafcutting ant Atta cephalotes were determined using individuals of 49 woody plant species from a tropical deciduous forest in Costa Rica. The palatability of plants was measured by presenting whole leaves to leafcutting ant foragers on trails and counting the number of pieces cut from leaves. The effectiveness of physical barriers to leaf cutting was evaluated by measuring the speed with which ants were able to cut leaves of varying toughness, trichome densities, and trichome lengths. Ecological Society of AmericaPlant secondary chemistry was highly correlated with the relative palatability of leaves, while palatability was only marginally correlated with trichome characteristics and plant nutritional quality and was uncorrelated with leaf toughness and water content. Highly palatable leaves generally contained hydrolyzable tannins, while most unpalatable leaves possessed nonpolar extracts found to deter leaf cutting in laboratory bioassays. Within the subset of highly palatable plants, leaf protein content was positively correlated with the number of pieces cut, indicating that secondary chemistry and nutrient availability interact to determine palatability. Decreases in plant palatability over time paralleled decreases in protein content. Ant size was the most important variable determining the rate at which ants cut leaves. Trichome characteristics were uncorrelated with the rate at which leaves were cut, while leaf toughness explained a small amount of the variance in cutting rate.The results suggest that leaf toughness and trichome characteristics within the ranges encountered by leafcutting ants in this tropical deciduous forest do not generally deter attack by ants. Instead, the results are consistent with the idea that leafcutting ants use a combination of plant secondary chemistry and nutrient availability to evaluate the quality of leaves.

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“…The case of Atta is particularly interesting because these ants maintain long-lasting trunk trails despite foraging on leaf resources that are patchy and highly ephemeral (Rockwood 1975;Fowler and Stiles 1980;Sheperd 1985). A typical adult colony may simultaneously maintain three-ten large trails, each as much as 30 cm wide and cleared of leaf litter to the bare ground (Weber 1972;Fowler and Robinson 1979).…”

Section: Introductionmentioning

confidence: 99%

Costs of trail construction and maintenance in the leaf-cutting ant Atta columbica

Howard

2001

Behavioral Ecology and Sociobiology

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Leaf-cutting ants of the genus Atta use trunk trails during foraging which may persist for months or years. The time and energy costs of trail construction and maintenance were estimated for colonies of Atta columbica on Barro Colorado Island, Panama, to determine if these costs are likely to constrain new trail construction and promote persistence of existing trails. Large workers 2.2-2.9 mm in headwidth participated in trail-clearing significantly more frequently than typical leaf-carriers, indicating that they may form a distinctive task group within the foraging force. Small litter items were carried off trails, while large ones were cut up before removal, greatly increasing the costs of removing large litter items. The average time cost of removing a kilogram of litter was estimated at 3,359 ant-hours, and energy costs at 4.6 kJ. Colonies maintained trail systems 267 m in length and 16.5 m 2 in area, and built an estimated 2.7 km of trail with an area of 134 m 2 during a year. Based on litter standing crop and estimates of litterfall rates, total costs to colonies averaged 11,000 antdays of work and the energy equivalent of 8,000 leaf burdens. These costs are small relative to the number of available workers and rates of mass harvest, suggesting that costs do not significantly constrain trail construction. Instead, trails may persist because they provide access to high-quality resources or because only a few trails are required to fully exploit the foraging territory.

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The Effects of Seasonality on Foraging in Two Species of Leaf-Cutting Ants (Atta) in Guanacaste Province, Costa Rica

Cited by 71 publications

References 13 publications

Leafcutting Ant Diet Selection: The Role of Nutrients, Water, and Secondary Chemistry

Leafcutting Ant Diet Selection: The Role of Nutrients, Water, and Secondary Chemistry

Leafcutting and Diet Selection: Relative Influence of Leaf Chemistry and Physical Features

Costs of trail construction and maintenance in the leaf-cutting ant Atta columbica

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