Sustained high levels of foliar herbivory of the mangrove Rhizophora stylosa by a moth larva Doratifera stenosa (Limacodidae) in north-eastern Australia

Journal Publication ResearchOnline@JCU
Duke, Norman C.
Norm Duke
Abstract

The moth larva, Doratifera stenosa (Lepidoptera: Limacodidae), was observed feeding voraciously in great numbers on mature leaves of Rhizophora stylosa in mangroves of Port Curtis in Central Queensland, NE Australia. This behaviour was considered unusual since mangroves, and Rhizophora species in particular, reportedly have few herbivores and relatively low levels of herbivory, less than 10%. During a two year period (1996-1998), larvae were observed consuming around 30-40% of leaves in the canopy each year, and the mangroves appeared able to sustain these high levels of herbivory. The impact on trees was assessed in conjunction with a study of the herbivore, its behaviour and life history in an attempt to explain the occurrence. Larvae were up to 1-2 cm each in length, bright green and gregarious, with numerous small, stinging hairs along their upper bodies. Feeding was in small cohort groups of 5-70 individuals which broke up immediately prior to each moult when they regrouped in much larger numbers of mixed cohorts to form single-file processions across branches, stems and prop roots. In this way, they moved to neighbouring trees with less affected foliage. One of the outstanding characteristics of this herbivore was its ability not to kill host trees although it appeared quite capable of doing so if it had remained on individual trees. By moving from tree to tree, the herbivore was able to heavily crop Rhizophora foliage in an apparently sustainable manner. These findings demonstrate the role and importance of foliar herbivory in severely affected forests and how such instances best not be ignored or treated as curiosities in future assessments of herbivory and forest turnover in mangrove ecosystems.

Journal

Wetlands Ecology and Management

Publication Name

Wetlands Ecology and Management

Volume

10

ISBN/ISSN

1572-9834

Edition

N/A

Issue

5

Pages Count

17

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N/A

Publisher

Springer

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EISSN

N/A

DOI

10.1007/BF03263357