Seed dispersal effectiveness increases with body size in New Zealand alpine scree weta (Deinacrida connectens)
Article first published online: 16 JAN 2012
© 2012 The Authors. Austral Ecology © 2012 Ecological Society of Australia
Volume 37, Issue 7, pages 800–806, November 2012
How to Cite
LARSEN, H. and BURNS, K. C. (2012), Seed dispersal effectiveness increases with body size in New Zealand alpine scree weta (Deinacrida connectens). Austral Ecology, 37: 800–806. doi: 10.1111/j.1442-9993.2011.02340.x
- Issue published online: 23 OCT 2012
- Article first published online: 16 JAN 2012
- Accepted for publication December 2011.
Weta are giant, flightless orthopterans that are endemic to New Zealand. Although they are known to consume fleshy fruits and disperse seeds after gut passage, which is unusual among insects, their effectiveness as seed dispersal mutualists is debated. We conducted a series of laboratory experiments on alpine scree weta (Deinacrida connectens) and mountain snowberries (Gaultheria depressa) to investigate how fruit consumption rates, the proportion of ingested seeds dispersed intact and weta movement patterns vary with weta body sizes. On average weta dispersed 252 snowberry seeds nightly and travelled at a rate of 4 m min−1. However, seed dispersal effectiveness varied over three orders of magnitude and was strongly associated with body sizes. Smaller weta consumed few snowberry seeds and acted primarily as seed predators. On the other hand, the largest weta consumed and dispersed thousands of seeds each night and appear to be capable of transporting seeds over large distances. Overall results indicate that scree weta shift from being weakly interacting seed predators to strongly interacting, effective seed dispersers as they increase in size.