Associational resistance protects mangrove leaves from crab herbivory
- 作者：Amy A. Erickson ; aerickso@lsus.edu ; Susan S. Bell sbell@usf.edu ; Clinton J. Dawes cdawes@usf.edu
- 关键词：Aratus pisonii ; Associational resistance ; Herbivory ; Mangrove ; Resource concentration hypothesis ; Rhizophora mangle
- 刊名：Acta OEcologica
- 出版年：2012
- 期刊代码：1_1146609x
- 类别：abs
- 出版时间：May, 2012
- 卷：41
- 期：Complete
- 页码：46-57
- 文件大小：856 K
摘要
While associational defenses have been well documented in many plant and algal ecosystems, this study is the first to document associational resistance in mangroves. Mangrove tree crab (Aratus pisonii) density and herbivory on three life-stages of the red mangrove (Rhizophora mangle) were documented in pure red versus mixed-species and predominantly non-red mangrove stands containing black (Avicennia germinans) and white (Laguncularia racemosa) mangroves in 1999-2000 in Tampa Bay, Florida. This study first established that R.聽mangle is the focal species in the context of associational resistance because it is damaged more than either of the other mangrove species. Next, it was hypothesized that crab density and leaf damage on R.聽mangle would be lower when in mixed-species and predominantly non-red versus red mangrove stands. A non-significant trend suggested that crab density varies among stands, and crab damage on R.聽mangle leaves was significantly lower in mixed-species and non-red stands. Mechanisms to explain associational resistance were examined. Positive Pearson correlations between the percent of adult R.聽mangle in a stand and both crab density and R.聽mangle leaf damage provided support for the resource concentration hypothesis. Limited support was found for the attractant-decoy hypothesis because the total amount of damaged leaves of all mangrove species combined typically differed among stands, suggesting that crabs were not shifting to alternative mangrove species to offset reduced availability of R.聽mangle leaves. Finally, while R.聽mangle seedlings were shorter in non-red stands compared to others, intra-specific differences in R.聽mangle leaf chemistry and sclerophylly among stands failed to explain associational patterns. These combined results argue for the need for additional experiments to elucidate mechanisms responsible for defensive plant associations in mangrove ecosystems and to determine whether such associations could be of use in mangrove restoration.