Majer, Cocquyt & Recher: Powdery bark in Eucalyptus accedens 
chrysomelid beetles from adhering to their surface 
(Edwards 1982). 
The final possibility is that the powder is simply a 
physical nuisance to the normal movement and activity 
of animals to which it adheres. The accumulation of 
powder around the mouthparts of the 1. chasei we studied 
suggests that they tried to remove the powder from their 
bodies. Possibly this diverted their attention or energy 
for climbing the trunks of E. accedens. Whatever the 
explanation, our bioassay with dowels shows that the 
powder effectively prevents ants from climbing the 
dowels, and thus can deter ants and potentially other 
arthropods from climbing the trunks. 
There may, of course, be other reasons why this tree 
species accumulates powder on the surface of its bark. 
Our data in Majer et al. (2002) indicate that the 
invertebrates that are apparently deterred from walking 
on the powderbark wandoo trunks represent several 
feeding guilds. Importantly, ants and sap-sucking 
hemipterans are noticeably less diverse on the 
powderbark wandoo than the wandoo (43 vs 54, and 9 vs 
15 species respectively in bark traps) (Majer et al. 2002). 
The powder does not totally exclude trunk-associated 
arthropods but, by reducing the abundance of bark¬ 
feeding species on the trunk, and by making it more 
difficult for folivores to reach the canopy of the tree 
(Proctor et al. 2002), the powder on the bark of E. accedens 
may reduce the overall levels of herbivory and associated 
injury to the tree. 
Acknoivledgements: This work was funded by a grant from the 
Australian Research Council. We thank Geraldine Garrioch for assisting 
with the ant baiting experiment. Dr Steve Errington for performing the 
triterpenoid analysis and Lydia Kupsky for plating the powder. Dr Elaine 
Davison identified the microorganisms in the powder, and Prof Neal 
Enright and Prof Byron Lamont and three anonymous referees 
commented on an earlier draft of this paper. 
References 
Brieskom H and Herrig H 1959 The chemical mechanism of the 
Liebermann-Burchard color reaction in steroids, terpenes, 
and their esters. Archiv fur Pharmacologie 292:485-496. 
Edwards PB 1982 Do waxes on juvenile Eucalyptus leaves 
provide protection from grazing insects? Australian Journal 
of Ecology 7: 347-352. 
Eigenbrode SD 1996 Plant surface waxes and insect behaviour. 
In: Plant Cuticles - An Integrated Functional Approach (ed G 
Kerstiens) Bios, Oxford, 201-222. 
Federle W, Maschwitz U, Fiala B, Riederer M and Hdlldober B 
1997 Slippery ant-plants and skilful climbers: selection and 
protection of specific ant partners by epicuticular wax blooms 
in Macaranga (Euphorbiaceae). Oecologia 112: 217-224. 
Haberlandt G 1909 Physiologische Pflanzenanatomie. Wilhelm 
Engelmann, Leipzig. 
Juniper BE 1986 The path to plant camivory. In: Insects and the 
Plant Surface (eds BE Juniper, TRE. Southwood) Edward 
Arnold, London, 195-218. 
Juniper BE 1995 Waxes on plant surfaces and their interactions 
with insects. In: Waxes: Chemistry, Molecular Biology and 
Functions (ed RJ Hamilton) Oily, West Ferry, Dundee, 157- 
174. 
Majer JD, Recher HF, Heterick BE and Postle AC 2002 The 
canopy, bark, soil and litter invertebrate fauna of the Darling 
Plateau and adjacent woodland near Perth, Western 
Australia, with reference to the diversity of forest and 
woodland invertebrates. Pacific Conservation Biology 7: 229- 
239. 
Majer JD, Recher HF, Graham R and Gupta R 2003 Trunk 
invertebrate faunas of Western Australian forests and 
woodlands: Influence of tree species and season. Austral 
Ecology 28: 629-641. 
Proctor HC, Montgomery KM, Rosen KE and Kitching RL 2002 
Are tree trunks habitats or highways? A comparison of 
oribatid mite assemblages from hoop-pine bark and litter. 
Australian Journal of Entomology 41: 294-9. 
Stork NE 1980 Role of wax blooms in preventing attachment to 
brassicas by the mustard beetle, Phaedon cochleariae. 
Entomologica Experimentalis et Applicata 28:100-107. 
83 
