Weaver Ants Increase Premature Loss of Leaves Used for Nest Construction in Rhizophora Trees¹

Abstract

Oecophylla ants utilize living leaves when they construct their nests. We investigated how Oecophylla smaragdina nests in southern Thailand affected leaf performance on the mangrove tree Rhizophora mucronata. Leaves used in nests and neighboring leaves showed a higher rate of premature leaf loss compared to control leaves farther from the nests. However, a tree's total cost due to the higher premature leaf loss was estimated to be approximately between 3‐ and 20‐fold lower than the benefit derived from ant protection, detected in a previous study (Offenberg et al. 2004).

REVIEW: Ants as tools in sustainable agriculture

“…On the other hand, only 0·25% of the leaves on ant trees were used in ant nests, and the associated costs were estimated to be 6–20 times lower than the benefits gained via a decreased leaf area removed by herbivores (Offenberg et al . , ). Similarly, nest leaves on Benin mango showed reduced leaf longevity, but the number of leaves used in nests was only between 0·42% and 1·2% (Anato et al .…”

Impact of African Weaver Ant Nests [Oecophylla longinoda Latreille (Hymenoptera: Formicidae)] on Mango [Mangifera indica L. (Sapindales: Anacardiaceae)] Leaves

“…Similarly, Offenberg et al (2006) observed that O. smaragdina showed a strong preference for young leaves on R. mucronata in a Thai mangrove. On the other hand, there was no size difference between the control leaves on nest and control shoots, showing that the nests did not affect the size of neighboring leaves.…”

“…Firstly, the number of leaves used to form nests was low, 0.7% in average. Similarly, Offenberg et al (2006) estimated that, O. smaragdina used as little as 0.25% of the leaves of the mangrove tree R. mucronata to form their nest. Thus, weaver ants in general use only few of the available leaves on trees to build their nests.…”

“…Further, on the negative side, weaver ants weave leaves together (Crozier et al, 2010) and deposit territorial marking on leaves (Offenberg, 2007) which may reduce the efficiency of photosynthesis on their host plant. Also, when ants interlace leaves and turn them out of their original position, they can increase tension on the leaf petiole and potentially cause a premature detachment of the leaf from the shoot (Dillwith et al, 1991;Riedell & Blackmer, 1999;Offenberg et al, 2006). Thus, Oecophylla nest building may result in indirect cost to the leaves used for their nest construction.…”

Weaver Ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae) Performance in Mango and Cashew Trees Under Different Management Regimens

“…Moreover, according to Offenberg et al (2006) weaver ants has a preference to use first position leaves for nest building because these leaves are still expanding and therefore smaller and more flexible than the older leaves and also more likely to host trophobionts. The characteristics of host plant leaves are therefore an important factor in the choice of nesting site.…”