Asian Myrmecology, Volume 2, Ecology and Distribution
Do tenants always pay their rent? The Asian ant-plant Pometia pinnata (Sapindaceae) and its leaf domatia provide free access to generalist ants
JOACHIM MOOG 1, KATJA ATZINGER 1, ROSLI HASHIM 2 & ULRICH MASCHWITZ 1,3
1 Zoological Institute, Dept. of Biological Sciences, J. W. Goethe University, Siesmayerstr. 70, 60054
Frankfurt am Main, Germany
2 Institute of Biological Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
3 Institute of Apidology, Dept. of Biological Sciences of J. W. Goethe University, Karl-von-Frisch-
Weg 2, 61440 Oberursel, Germany
Abstract. The tree Pometia pinnata Forst. forma glabra (Bl.) Jacobs is an ant-plant
that provides lodging (leaf domatia) and food (extrafloral nectar, excretions of coccids)
for ants. The leaf domatia are formed by two pairs of strongly modified basal leaflets.
In total, 63 ant species from 18 genera and 4 subfamilies were encountered in the
domatia of the host in the study area (Ulu Gombak, Malaysia). We found that the ant⁄Pometia relationship has two stages: (i) an early ‘myrmecophilic’ phase of juvenile,
domatia-free plants, and (ii) a ‘myrmecophytic’ phase of older plants in which ants
nest in domatia. In the myrmecophilic stage, our short-term experiment revealed a
significant greater loss of young leaflets when ants were excluded than on control
plants to which ants had access; however, the area of remaining leaf was not different
between treatment and control. Similar ambiguous effects were observed in the
myrmecophytic stage: a snapshot census revealed no significant difference in the
standing level of leaf herbivore damage between branches with and without nesting
ants. However, our survey indicated that ant species differed in the protection provided
to their host. Our data also suggest that presence of nesting ants substantially
reduces damage to the leaf rachis.
Keywords: ant-plant interaction, protection mutualism, conditional outcome, leaf
domatia, myrmecophyte, Pometia, Lepisanthes, Malaysia, SE Asia