Department of Public Health and Tropical Medicine, lames Cook University, Townsville, QLD 4811, Australia.
Mistletoe host-resemblance: A study of herbivory, nitrogen and moisture in two Australian mistletoes and their host trees
Article first published online: 28 JUL 2006
Australian Journal of Ecology
Volume 22, Issue 4, pages 395–403, December 1997
How to Cite
CANYON, D. V. and HILL, C. J. (1997), Mistletoe host-resemblance: A study of herbivory, nitrogen and moisture in two Australian mistletoes and their host trees. Australian Journal of Ecology, 22: 395–403. doi: 10.1111/j.1442-9993.1997.tb00689.x
- Issue published online: 28 JUL 2006
- Article first published online: 28 JUL 2006
- Accepted for publication lanuary 1997
- cryptic mimicry;
- water relations;
- leaf shape;
Abstract For 150 years mistletoe host-resemblance has been an unsolved puzzle. Mimicry, camouflage, host protection and shape modification by the host tree have all been advanced as possible solutions. No extended examination of herbivory of host-parasite pairs has ever been done, however, to put these explanations to the test. The study was carried out in northeastern Australia from March to July 1994. Rates of leaf herbivory were estimated for seven individuals of Amyema biniflora Barlow (a cryptic mistletoe species), Dendrophthoe glabrescens (Blakely) Barlow (a non-cryptic mistletoe species) and their host trees (Eucalyptus tessellaris F. Muell. and Eucalyptus platyphylla F. Muell., respectively). In addition three measures of leaf palatability–nitrogen content, moisture content and toughness–were also assessed. Variability in mistletoe leaf shape was quantified by measuring the leaf widths of mistletoes on a variety of host tree species. Mistletoes sustained greater levels of herbivory compared to their host trees, but herbivory did not differ between mistletoe species. The non-cryptic mistletoe had lower levels of nitrogen compared to its host tree, but there was no difference in nitrogen levels between the cryptic mistletoe and its host. The moisture content of mistletoe leaves was greater than that of their hosts but not between mistletoe or host species. The mistletoe species had tougher leaves than their host trees. Leaf shape was different for one species of mistletoe growing on different host trees, but constant for another species of mistletoe. The results contradict, in some crucial aspect, all of the mimicry hypotheses currently on offer.