Constraints on the utilisation of the invasive Chinese tallow tree Sapium sebiferum by generalist native herbivores in coastal prairies
Version of Record online: 5 FEB 2004
Volume 29, Issue 1, pages 66–75, February 2004
How to Cite
Lankau, R. A., Rogers, W. E. and Siemann, E. (2004), Constraints on the utilisation of the invasive Chinese tallow tree Sapium sebiferum by generalist native herbivores in coastal prairies. Ecological Entomology, 29: 66–75. doi: 10.1111/j.0307-6946.2004.00575.x
- Issue online: 5 FEB 2004
- Version of Record online: 5 FEB 2004
- Accepted 10 September 2003
- Behavioural constraint;
- enemies hypothesis;
- generalist herbivore;
- invasive species;
- Sapium sebiferum
Abstract. 1. Introduced plants generally have lower generalist herbivore loads than native plants. Herbivores may be avoiding a potentially edible food source (Behavioural Constraint Hypothesis) or defences of introduced plants may be unusually toxic (Novel Defence Hypothesis).
2. To examine these hypotheses, acridid grasshoppers (Melanoplus angustipennis and Orphullela pelidna) were enclosed in a Texas grassland. Each enclosure contained native prairie vegetation and a seedling of either introduced Sapium sebiferum (Chinese tallow tree) or native Celtis laevigata (hackberry). Sapium invades many ecosystems in the south-east U.S.A. Celtis seedlings also establish in these ecosystems.
3. Although grasshoppers usually feed sparingly on Sapium, in field enclosures they fed heavily on this introduced tree species, supporting a role for behavioural avoidance. In laboratory feeding trials, M. angustipennis grasshoppers preferred Sapium foliage over the foliage of three native tree species. In a greenhouse experiment, M. angustipennis individuals fed more on Sapium in prairie mesocosms if they were conditioned on Sapium.
4. In another field experiment with single seedlings in enclosures, grasshoppers consumed similar amounts of Sapium from its introduced (Texas, U.S.A.) and native (China) ranges, suggesting that Sapium may have been a suitable host plant since it was introduced. Behavioural avoidance by generalist herbivores may contribute to Sapium's low herbivore load in its introduced range.