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Patterns of Azteca ants’ defence of Cecropia trees in a tropical rainforest: support for optimal defence theory
Author(s) -
Gianoli Ernesto,
Sendoya Sebastián,
Vargas Fernando,
Mejía Paula,
Jaffé Rodolfo,
Rodríguez Mayanín,
Gutiérrez Adrián
Publication year - 2008
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/s11284-007-0454-0
Subject(s) - cecropia , herbivore , biology , tropical rainforest , patrolling , ecology , alate , ant colony , rainforest , botany , geography , mathematics , homoptera , archaeology , algorithm , aphididae , ant colony optimization algorithms , pest analysis
Optimal defence theory (ODT) predicts that, whereas high risk of herbivory should select for high constitutive levels of defence, induced defences should be more advantageous in environments with a low probability of herbivory. In the present field study, conducted on the Azteca – Cecropia ant–plant system in a Neotropical rainforest, we evaluated whether the constitutive and induced ant defence of leaves are directly and inversely related to an estimate of herbivory risk, respectively. To assess the constitutive level of Azteca defence in Cecropia obtusifolia trees, we recorded the number of ants patrolling undamaged leaves. To evaluate the induced level of Azteca defence, the same leaves were subjected to simulated herbivory by punching circular holes in them. We recorded the maximum number of ants patrolling the damaged leaves from 2 to 15 min after damage. Past herbivory (% defoliation of old leaves) was assumed to indicate a risk of herbivory. Regression analyses showed that, whereas the constitutive level of ant patrolling was positively associated with the magnitude of herbivory on old leaves, there was a negative association between the magnitude of induced ant defence and past herbivory. These preliminary results lend support to ODT.