Herbivory of Leaf-Cutting Ants

by Wirth, Rainer; Herz, Hubert; Ryel, Ronald J.; Beyschlag, Wolfram; Holldobler, Bert; Wirth, Rainer

• ISBN13: 9783540438960
• ISBN10: 3540438963
• Format: Hardcover
• Copyright: 2003-03-01
• Publisher: Springer Verlag

Summary

Plant-animal interactions have become a focus of ecological research, with the processes of herbivory being of special interest. This volume examines the interactions of leaf-cutting ants with the rainforest vegetation on Barro Colorado Islands in Central America. It is the synthesis of field research on multiple scales extending over a period of several years. This work can serve as a model study summarizing and extending knowledge about herbivorous insect-plant relationships, and the resulting consequences on structural and functional features of tropical ecosystems. The text is an invaluable reference for researchers and land managers working in the fields of plant-animal interactions, herbivory, community ecology and biodiversity.

Table of Contents

About This Book	1	(4)
The Natural History of Leaf-Cutting Ants	5	(44)
The Significance of Social Insects	5	(2)
The Fungus Growers	7	(2)
The Natural History of the Leaf-Cutting Ants of the Genus Atta	9	(40)
Colony Foundation in Atta	9	(5)
Division of Labor in Atta Colonies	14	(3)
The Maintenance of Fungal Hygiene	17	(3)
Communication and Foraging in Atta Colonies	20	(4)
Leaf-Cutting Behavior and Load-Size Determination	24	(4)
Communication Between the Fungus Garden and Workers in Atta Colonies	28	(3)
Color Plates 1--16	31	(18)
The Study Area -- Barro Colorado Island	49	(6)
Location and History	49	(2)
Geology and Soils	51	(1)
Climatic Conditions	51	(1)
Vegetation Structure and Composition	52	(1)
Fauna	53	(1)
Research Locations	54	(1)
Species Composition of the Forest	55	(6)
Selection and Setup of the Study Plot	55	(1)
Vegetation Inventory	56	(1)
Abundances and Diversity of Tree Species	57	(4)
Forest Light Regimes	61	(10)
Seasonal and Spatial Light Patterns in the Understory	61	(5)
Measuring Irradiance	61	(2)
Horizontal Distribution of Irradiance	63	(1)
Seasonal Aspects	64	(2)
Vertical Light Variability	66	(5)
Measuring Vertical Light Profiles	66	(1)
Vertical Distribution of Light	67	(4)
Canopy Structure of the Forest	71	(12)
Theory	71	(1)
Measuring LAI and Foliage Orientation	72	(1)
Vertical Distribution of Foliage Angles	73	(1)
Spatial and Temporal Characteristics of LAI Distribution	74	(6)
Vertical LAI Distribution	74	(3)
Horizontal LAI Distribution and Seasonal Variation	77	(3)
LAI Measurements with the Li-Cor LAI-2000	80	(1)
Comparison of the Study Plot with Other Parts of the BCI Forest	81	(2)
Colony Dynamics	83	(8)
Colony Distribution and Density	84	(4)
Colony Movements	88	(1)
Nest Size	89	(1)
Nest Trees	90	(1)
Harvest Dynamics	91	(20)
Annual Pattern of Foraging Activity	91	(8)
Measuring Foraging Activity	91	(1)
Plant Biomass Harvest	92	(7)
Size and Weight of Harvested Fragments	99	(2)
Diurnal Course of Foraging Activity	101	(4)
The Typical Pattern and Its Variability	101	(3)
The Role of Precipitation	104	(1)
Rapid Estimation of Harvesting Rates	105	(6)
Estimating Colony Harvest	105	(2)
Estimating the Annual Harvest of the Atta colombica Population	107	(3)
General Suitability of Linear Regression Models for Estimating Harvest Rates	110	(1)
The Trail System	111	(10)
Mapping and Monitoring of Foraging Trails	112	(1)
Annual Course of Foraging Trail Establishment	112	(3)
Frequency of Trail Establishment Throughout the Year	115	(1)
Spatial and Temporal Patterns of Foraging	116	(1)
Foraging Activity in the Canopy	117	(1)
Estimating Foraging Area	117	(2)
Trunk Trail Systems as Determinants of Foraging Patterns	119	(2)
Host Plant Selection	121	(10)
Measuring Electivity	121	(1)
Harvest Preferences of Colony I Throughout the Year	122	(9)
Characterization of the Harvested Species	122	(6)
Harvest Diversity and Selection	128	(3)
Herbivory Rates	131	(20)
Factors Affecting Estimates of Herbivory	131	(3)
Herbivory Rates at the Landscape Level	134	(4)
Herbivory at the Colony Level	138	(5)
Leaf Harvesting Rates Along Trunk Trail III	138	(1)
Defining a Discrete Foraging Area	139	(1)
Annual Foliage Loss from the Foraging Area	140	(3)
Herbivory at the Individual Tree Level	143	(1)
Methodological Details	143	(1)
Estimation of Annual Leaf Harvest from Selected Individual Host Plants	143	(1)
Annual Pattern of Leaf Consumption and Herbivory Rates	144	(7)
Comparison of Herbivory at Different Levels	148	(3)
Herbivory and Light	151	(14)
Effects of Foliage Removal on Light Distribution and Intensity	151	(6)
Changes in Understory Light Climate of the Foraging Area	151	(2)
Changes in Light Climate of an Individual Tree	153	(2)
Simulated Changes in Canopy Light Intensity	155	(2)
Canopy Photosynthesis	157	(4)
Simulated Changes in Whole Canopy Photosynthesis	157	(3)
Simulated Effects on Photosynthesis of Single Trees	160	(1)
Compensatory Growth	161	(4)
Seed Dispersal by Leaf-Cutting Ants	165	(6)
Fruit Harvest from the Pioneer Tree Miconia argentea (Melastomataceae)	166	(1)
The Fate of Harvested Miconia Seeds	167	(1)
Ecological Significance of Atta Fruit Harvest	168	(3)
Nutrient Cycling and Water Relations	171	(12)
Nutrient Cycling	171	(8)
Herbivores and Nutrient Cycling	171	(2)
Nutrient Concentrations in Harvested Leaves and Refuse	173	(2)
Nutrient Dynamics Within the Colony	175	(2)
Community Level Effects	177	(2)
Water Relations	179	(4)
The Effect of Leaf Wounding	179	(1)
Whole-Canopy Level Effects	180	(1)
Simulated Effects of Herbivory on Transpiration of Single Trees	181	(2)
Conclusions: Ecosystem Perspectives	183	(12)
Disturbance, Herbivory, and Biodiversity	184	(3)
Leaf-Cutting Ants and the Spatial and Temporal Heterogeneity of Resources	187	(4)
Light Heterogeneity	188	(2)
Nutrient and Soil Heterogeneity	190	(1)
Heterogeneity of Water Availability	191	(1)
Leaf-Cutting Ants and Ecosystem Biodiversity	191	(4)
References	195	(26)
Taxonomic Index	221	(4)
Subject Index	225