Ants on swollen-thorn acacias: species coexistence in a simple system

  title={Ants on swollen-thorn acacias: species coexistence in a simple system},
  author={Truman P. Young and Cynthia H. Stubblefield and Lynne A. Isbell},
Abstract On the black cotton soils of the Laikipia ecosystem in Kenya, two swollen-thorn acacia species support nine ant species, four of which are apparently obligate plant-ants. Among the ants, there are five species of Crematogaster, two species of Camponotus, and one each of Tetraponera and Lepisota. Acacia drepanolobium is host to four ant species that are both common and mutually exclusive. These four ant species, and an additional non-exclusive ant species, tend to occur on trees of… 

Ecological barriers to early colony establishment in three coexisting acacia-ant species in Kenya

In black cotton uplands in East Africa, four symbiotic acacia-ant species compete for possession of a single swollen thorn tree species, Acacia drepanolobium, and yet coexist at fine spatial scales to determine what factors influence their success.

Thorn-dwelling ants provide antiherbivore defence for camelthorn trees, Vachellia erioloba, in Namibia

It is shown that experimental exclusion of ants leads to greater levels of herbivory on trees, highlighting the potential of the V. erioloba–ant mutualism for studying ant–plant interactions that involve multiple, simultaneously resident thorn-dwelling ant species.

Sterilization and canopy modification of a swollen thorn acacia tree by a plant-ant

It is proposed that the high density of ant-trees and low diversity of tree species in this savanna habitat have selected for induced, parasitic pruning of host trees by this competitively subordinate ant species.

Distinctive fungal communities in an obligate African ant-plant mutualism

This work reports on the first record of such ant-specific fungal community-level differences on the same myrmecophytic host species, and indicates that domatium fungal communities are associated with the ant species occupying the tree.

Causes and consequences of coexistence in the Vachellia drepanolobium ant-plant mutualism

This paper uses RADseq derived SNPs to identify relatedness of workers in colonies to test the hypothesis that competitively dominant ants reach large colony sizes due to polygyny, and finds that variation in queen number is not associated with competitive ability.

Short-term dynamics of an acacia ant community in Laikipia, Kenya

Observed correlations between tree vigor and takeover direction suggest that colony growth of dominant ant species is either favored in more productive microhabitats, or that such colonies differentially seek out healthier trees for conquest.

The Curious Case of the Camelthorn: Competition, Coexistence, and Nest-Site Limitation in a Multispecies Mutualism

Comparison of this unusual case with others suggests that spatial scale is crucial to coexistence or competitive exclusion involving multiple ant species and coexistence may be facilitated when co-occurring ant species diverge strongly on at least one niche axis.

Relationship between Plant Size and Ant Associates in Two Amazonian Ant-Plants1

It was found that early in colony development, queens of C. laevis moved off their host plants to build satellite nests in dead twigs on the ground, a behavior not seen in the other two species and one that possibly renders colonies more vulnerable to mortality from predation, flooding, or nest decay.

Interspecific and temporal variation of ant species within Acacia drepanolobium ant domatia, a staple food of patas monkeys (Erythrocebus patas) in Laikipia, Kenya

It is suggested that greater consideration be given to species differences in animal food choices and that further studies be conducted to examine the degree to which ants influence energy intake and reproduction in other primates.

Disruption of a protective ant-plant mutualism by an invasive ant increases elephant damage to savanna trees.

In Laikipia, Kenya, the invasion of big-headed ants may strongly alter the dynamics and diversity of East Africa's whistling thorn savannas by disrupting this system's keystone acaciaant mutualism.



in Macaranga species with different de,grees of ant association

The hypothesis that non-specific, facultative associations with ants can be advantageous for Macaranga plants is supported and food bodies appear to have lower attractive value for opportunistic ants than EFN and may require a specific dietary adaptation.


  • D. Janzen
  • Environmental Science
    Evolution; international journal of organic evolution
  • 1966
The coevolution of one of the more thoroughly studied mutualistic systems in the New World tropics: the interdependency between the swollen-thorn acacias and their ant inhabitants is discussed.

Assembly of Mangrove Ant Communities: Patterns of Geographical Distribution

The patterns of aggression and avoidance were consistent with, and presumed to be the cause of, the experimental results and patterns of geographical distribution.

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Experiments with artificial nests showed that colonization was not reduced by the presence of resident ant colonies, and the ecology of a leaf litter assemblage of twig-dwelling ants in lowland tropical wet forest was contrasted with the better known ecologies of ground- and tree-d Dwelling ants.

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More aggressive ant species (Hymenoptera: Formicidae) provide better protection for soft scales and mealybugs (Homoptera: Coccidae, Pseudococcidae).

For 11 sets of interacting species near Madang, Papua New Guinea, coccoids attended by relatively inoffensive ants were more heavily parasitized than those attended by more aggressive ants, though the precise form and effectiveness of this protection differed between different sets of interaction species.

Extrafloral nectaries: a defense against ant-Homoptera mutualisms?

Predation causing synchronous declin phases in icrotine and shrew populations in western Finland, and the effects of morphology and body size on rates of owl predation on desert rodents.

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One of the central problems in ecology is to explain species diversity in communities, and a considerable number of hypotheses with this purpose have been formulated during the last three decades.

Predator-Prey Role Reversal in a Marine Benthic Ecosystem

Rock lobsters transferred to Marcus Island were overwhelmed and consumed by the whelks, reversing the normal predatorprey relation between the two species, and may represent multiple states of the same ecosystem.