Size-related foraging behaviour of the leaf-cutting ant Atta colombica

1991 ◽  
Vol 69 (6) ◽  
pp. 1530-1533 ◽  
Author(s):  
Dave Shutler ◽  
Adele Mullie
Keyword(s):  
Body Size ◽  
Leaf Litter ◽  
Tree Species ◽  
Foraging Behaviour ◽  
Foraging Theory ◽  
Costa Rican ◽  
Leaf Cutting ◽  
Foraging Trail ◽  
Atta Colombica ◽  
Load Mass

In a Costa Rican forest adjacent to cattle pasture, larger individuals of the leaf-cutting ant Atta colombica carried heavier loads and foraged farther from the colony, as predicted by foraging theory. Counter to foraging theory, individual ants did not increase their load mass if they foraged farther from the colony. However, the colony avoided this apparent inefficiency by sending larger ants to more distant trees. The colony harvested simultaneously from several individuals of the same tree species, even though distant trees were twice as far from the colony as nearby trees. The reasons for this behaviour require further investigation. In a wide foraging trail, larger ants travelled faster than their smaller counterparts. In addition, ant velocity was reduced when loads were experimentally supplemented, and increased when loads were experimentally reduced. Ants using narrow trails in the leaf litter may all be constrained to travel at the same speed, irrespective of load or body size, simply because they get in each other's way.

scholarly journals Integrating the host plant phylogeny, plant traits, intraspecific competition and repeated measures using a phylogenetic mixed model of field behaviour by polyphagous herbivores, the leaf-cutting ants

2019 ◽  
Author(s):  
Manasee Weerathunga ◽  
Alexander S. Mikheyev
Keyword(s):  
Tree Species ◽  
Repeated Measures ◽  
Foraging Behaviour ◽  
Mixed Model ◽  
Plant Traits ◽  
Relative Role ◽  
Complex Investigation ◽  
Plant Phylogeny ◽  
Wide Range ◽  
Leaf Cutting

Herbivores use a wide range of factors to choose their host, including their own physiological states, physical characteristics of plants, and the degree of competition. Field observations of herbivores in their native habitats provide a means for simultaneously estimating the relative importance of these factors, but statistical analysis of all these factors may be challenging. Here we used a 7-wk dataset of leaf-cutting ant (Atta cephalotes) foraging in a diverse neotropical arboretum containing 193 tree species (822 trees) to examine the relative role of tree phylogeny, territoriality and tree functional characteristics using a phylogenetic generalized least squares (PGLS) model. We observed that 54 tree species (117 trees) were foraged by the ants. This pattern was not random, but reflected known features of leaf-cutting ant foraging behaviour, such as the preference for larger trees and the decreased likelihood of foraging at the periphery of a colony’s territory. However, random effects such as tree phylogeny, the identity of individual trees and colony-specific effects, explained most of the variation in foraging data. A significant phylogenetic effect on foraging likelihood (λ = 0.28), together with repeated measures of foraging on the same tree species, allowed estimation of relative palatability for each plant species. PGLS models can be flexibly scaled to include other covariates for even more complex investigation of foraging behaviour, and the link function can be modified to include the amount of plants foraged. As a result, PGLS can be used as a flexible framework for the study of LCA foraging.

scholarly journals Integrating host plant phylogeny, plant traits, intraspecific competition and repeated measures using a phylogenetic mixed model of field behaviour by polyphagous herbivores, the leaf-cutting ants

2020 ◽  
Vol 36 (2) ◽  
pp. 80-86
Author(s):  
Manasee Weerathunga ◽  
Alexander S. Mikheyev
Keyword(s):  
Tree Species ◽  
Repeated Measures ◽  
Foraging Behaviour ◽  
Mixed Model ◽  
Plant Traits ◽  
Relative Role ◽  
Complex Investigation ◽  
Plant Phylogeny ◽  
Wide Range ◽  
Leaf Cutting

AbstractHerbivores use a wide range of factors to choose their host, including their own physiological states, physical characteristics of plants and the degree of competition. Field observations of herbivores in their native habitats provide a means for simultaneously estimating the relative importance of these factors, but statistical analysis of all these factors may be challenging. Here we used a 7-week dataset of leaf-cutting ant (Atta cephalotes) foraging in a diverse Neotropical arboretum containing 193 tree species (822 trees) to examine the relative role of tree phylogeny, territoriality and tree functional characteristics using a phylogenetic generalized least squares (PGLS) model. We observed that 54 tree species (117 trees) were foraged by the ants. This pattern was not random, but reflected known features of leaf-cutting ant foraging behaviour, such as a preference for larger trees and the decreased likelihood of foraging at the periphery of a colony’s territory. However, random effects such as tree phylogeny, the identity of individual trees and colony-specific effects explained most of the variation in foraging data. A significant phylogenetic effect on foraging likelihood (λ = 0.28), together with repeated measures of foraging on the same tree species, allowed estimation of relative palatability for each plant species. PGLS models can be flexibly scaled to include other covariates for even more complex investigation of foraging behaviour, and the link function can be modified to include the amount of plants foraged. As a result, PGLS can be used as a flexible framework for the study of LCA foraging.

A new species of the subgenus Scheloribates (Topobates) (Acari: Oribatida: Scheloribatidae) from Panama

2020 ◽  
Vol 29 (2) ◽  
pp. 278-283
Author(s):  
S.G. Ermilov
Keyword(s):  
New Species ◽  
Body Size ◽  
Leaf Litter ◽  
Related Species ◽  
Large Body ◽  
Oribatid Mite ◽  
Neotropical Region ◽  
Large Body Size ◽  
First Time ◽  
A New Species

The oribatid mite subgenus Scheloribates (Topobates) Grandjean, 1958, is recorded from the Neotropical region for the first time. A new species of this subgenus is described from the leaf litter collected in Cayo Agua Island, Panama. Scheloribates (Topobates) panamaensis sp. nov. differs from its related species by the very large body size and presence of a strong ventrodistal process on the leg femora II–IV.

Ants accelerate litter decomposition in a Costa Rican lowland tropical rain forest

2012 ◽  
Vol 28 (5) ◽  
pp. 437-443 ◽  
Author(s):  
Terrence P. McGlynn ◽  
Evan K. Poirson
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Litter Decomposition ◽  
Rain Forest ◽  
Costa Rican ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Food Web Structure ◽  
Litter Bags ◽  
Lowland Rain Forest

Abstract:The decomposition of leaf litter is governed, in part, by litter invertebrates. In tropical rain forests, ants are dominant predators in the leaf litter and may alter litter decomposition through the action of a top-down control of food web structure. The role of ants in litter decomposition was investigated in a Costa Rican lowland rain forest with two experiments. In a mesocosm experiment, we manipulated ant presence in 50 ambient leaf-litter mesocosms. In a litterbag gradient experiment, Cecropia obtusifolia litter was used to measure decomposition rate constants across gradients in nutrients, ant density and richness, with 27 separate litterbag treatments for total arthropod exclusion or partial arthropod exclusion. After 2 mo, mass loss in mesocosms containing ants was 30.9%, significantly greater than the 23.5% mass loss in mesocosms without ants. In the litter bags with all arthropods excluded, decomposition was best accounted by the carbon: phosphorus content of soil (r2 = 0.41). In litter bags permitting smaller arthropods but excluding ants, decomposition was best explained by the local biomass of ants in the vicinity of the litter bags (r2 = 0.50). Once the microarthropod prey of ants are permitted to enter litterbags, the biomass of ants near the litterbags overtakes soil chemistry as the regulator of decomposition. In concert, these results support a working hypothesis that litter-dwelling ants are responsible for accelerating litter decomposition in lowland tropical rain forests.

Prey Body Size and Ranking in Zooarchaeology: Theory, Empirical Evidence, and Applications from the Northern Great Basin

2011 ◽  
Vol 76 (3) ◽  
pp. 403-428 ◽  
Author(s):  
Jack M. Broughton ◽  
Michael D. Cannon ◽  
Frank E. Bayham ◽  
David A. Byers
Keyword(s):  
Body Size ◽  
Great Basin ◽  
Diet Breadth ◽  
Foraging Theory ◽  
Return Rate ◽  
The Body ◽  
Foraging Efficiency ◽  
Large Prey ◽  
Abundance Indices ◽  
Game Hunting

The use of body size as an index of prey rank in zooarchaeology has fostered a widely applied approach to understanding variability in foraging efficiency. This approach has, however, been critiqued—most recently by the suggestion that large prey have high probabilities of failed pursuits. Here, we clarify the logic and history of using body size as a measure of prey rank and summarize empirical data on the body size-return rate relationship. With few exceptions, these data document strong positive relationships between prey size and return rate. We then illustrate, with studies from the Great Basin, the utility of body size-based abundance indices (e.g., the Artiodactyl Index) when used as one component of multidimensional analyses of prehistoric diet breadth. We use foraging theory to derive predictions about Holocene variability in diet breadth and test those predictions using the Artiodactyl Index and over a dozen other archaeological indices. The results indicate close fits between the predictions and the data and thus support the use of body size-based abundance indices as measures of foraging efficiency. These conclusions have implications for reconstructions of Holocene trends in large game hunting in western North America and for zooarchaeological applications of foraging theory in general.

Foraging behaviour of Armadillidium vulgare (Isopoda: Oniscidea) in heterogeneous environments

Behaviour ◽  
2004 ◽  
Vol 141 (2) ◽  
pp. 233-244 ◽  
Author(s):  
Joanne Tuck ◽  
Mark Hassall
Keyword(s):  
Leaf Litter ◽  
Foraging Behaviour ◽  
Walking Speed ◽  
Optimal Foraging Theory ◽  
Heterogeneous Environments ◽  
Intake Rate ◽  
High Quality ◽  
Turning Angle ◽  
Quality Food ◽  
Armadillidium Vulgare

AbstractForaging behaviour of Armadillidium vulgare was observed in laboratory arenas in which the spatial distribution of patches of high quality food (powdered dicotyledonous leaf litter) was varied within a background of low quality food (powdered grass leaf litter). The hypotheses that the foraging behaviour and foraging path of A. vulgare would be influenced by food quality and the patchiness of high quality food resources were tested. More time was spent in high quality food patches than in low quality food backgrounds than expected by chance in all heterogeneity treatments, but an increasingly higher percentage of time was spent in low quality food as the high quality food became more clumped in space. More time was spent searching, but less time was spent feeding in low quality food backgrounds than in high quality food patches in all the treatments. Walking speed was found to be lower in high quality food patches than in low quality food backgrounds and this was not affected by treatment. Turning frequency and turning angle were found to be higher in high quality food patches than in low quality backgrounds. Turning frequency in low quality food backgrounds decreased as the high quality food became more clumped in space, whereas turning angle in high quality food patches significantly increased in the patchy, but then decreased again in the clumped treatment. The effects of varying the spatial heterogeneity of high quality foods on the trade-off between costs of searching and intake benefits for saprophages are discussed in relation to predictions from optimal foraging theory for circumstances when intake rate maximisation is affected by the constraint of limited nutrients.

An extensive study of the foraging ecology of beavers (Castor canadensis) in relation to habitat quality

2004 ◽  
Vol 82 (6) ◽  
pp. 922-933 ◽  
Author(s):  
D Gallant ◽  
C H Bérubé ◽  
E Tremblay ◽  
L Vasseur
Keyword(s):  
Habitat Quality ◽  
Foraging Behaviour ◽  
Foraging Ecology ◽  
Castor Canadensis ◽  
Central Place ◽  
Foraging Theory ◽  
Extensive Study ◽  
Food Items ◽  
Partial View ◽  
Selection Of

The objective of this study was to examine the foraging behaviour of the beaver (Castor canadensis Kuhl, 1820) and to explain its selection of terrestrial woody plant species according to central place foraging theory. Limitations in variety of food items in most studies with regard to size and (or) distance from the central place and information on availability of forage choices give a partial view of the subject. In this study, the theory is tested in a natural environment with high variability in food items with regard to these factors. Foraging choices by beavers were inspected by measuring variables on cut and uncut trees of every species encountered within 1 m of trail systems made by 25 beaver colonies in Kouchibouguac National Park in New Brunswick, Canada, thereby quantifying the availability of the different food items. The effect of habitat quality (food availability) on the foraging behaviour of beavers was also tested. The results of this study suggest that with increasing distance from the pond, beavers in high-quality habitats selected fewer, but larger, trees and are more species selective. This selectivity was diminished in habitats of lower quality. The results of this study are consistent with the predictions of the central foraging theory.

Leaf litter of invasive Chinese tallow (Triadica sebifera) negatively affects hatching success of an aquatic breeding anuran, the Southern Leopard Frog (Lithobates sphenocephalus)

2012 ◽  
Vol 90 (8) ◽  
pp. 991-998 ◽  
Author(s):  
C.K. Adams ◽  
D. Saenz
Keyword(s):  
Dissolved Oxygen ◽  
Leaf Litter ◽  
Tree Species ◽  
Quality Parameters ◽  
Leopard Frog ◽  
Stages Of Development ◽  
Triadica Sebifera ◽  
Chinese Tallow ◽  
Invasive Tree ◽  
Invasive Tree Species

Chinese tallow (Triadica sebifera (L.) Small) is an aggressive invasive tree species that can be abundant in parts of its non-native range. This tree species has the capability of producing monocultures, by outcompeting native trees, which can be in or near wetlands that are utilized by breeding amphibians. Existing research suggests that leaf litter from invasive Chinese tallow reduces survival in larval anurans. The purpose of this study was to determine the effects of Chinese tallow leaf litter on anuran eggs. We exposed eggs of the Southern Leopard Frog ( Lithobates sphenocephalus (Cope, 1886)) at various stages of development to different concentrations of Chinese tallow leaf litter to determine survival. Eggs in the earliest stages of development that we exposed to tallow leaf litter died, regardless of concentration; however, some more-developed eggs exposed to tallow leaf litter did hatch. We determined that the greater the concentration of tallow leaf litter, the lower the dissolved oxygen and pH levels we observed. We suggest that changes in these water-quality parameters are the cause of the observed mortality of anuran eggs in our experiments. Eggs exposed to water containing tallow leaf litter with dissolved oxygen <1.59 mg/L and a pH <5.29 did not survive to hatching.

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