|
A new study by French scientists shows that when the ants are removed from their host in an ant-plant mutualism, the host plant suffer more damage from herbivores. They, furthermore, find that ants patrol more often on a young and vulnerable leaves, but are rapidly recruited to leaf wounds.
The so-called myrmecoophyte plants live in a close mutualism with ants. They offer the ants shelter in thorns, hollow stems or curled leaves and food in the form of extra-floral nectar or food bodies. In return the ants protects the plant by removing encroaching competitors and fungal pathogens, killing or scaring off herbivores – the ants usually have painful stings and are so aggressive that they can deter even large herbivores.
The team from the Paul Sabatier University in Toulouse studied the tropical shrub Hirtella physophora and its ant partner Allomerus decemarticulatus in French Guiana. In the first study they manually removed all individual ants and brood from 75 plants with a similar number functioning as controls. The results showed that in the long term (8 months), plants without ants suffered significantly higher herbivory rates than plants with ants.
In a second set of the experiments the French biologists observed the number of ants patrolling different parts of the plants and measurement recruitment to artificially wounded leaves. They found that ants patrol in higher numbers and more frequent on young leaves compared to old, but that ants appear in great numbers on both young and mature leaves, if they are being damaged.
The scientists thus show without any doubt that the ant-plant relationship is indeed a mutualistic one with great benefits for the plant. They, furthermore, find that the indirect defence of the plant given by the ants adhere to the optimal defence theory, which predicts that must effort should go to protect the most vulnerable parts.
Source:
Julien Grangier, Alain Dejean, Pierre-Jean G. Malé and Jérôme Orivel (2008). Indirect defense in a highly specific ant–plant mutualism. Naturwissenschaften 95, 909-915.
 Add as favourites (19) |  Quote this article on your site | Views: 1347 | E-mail
Only registered users can write comments.
Please login or register. Powered by AkoComment Tweaked Special Edition |
