Chemical induction in mangrove crab megalopae. Ucides cordatus (Ucididae): Do young recruits emit metamorphosis-triggering odours as do conspecific adults?

Simith, Darlan de Jesus de Brito; Abrunhosa, Fernando Ara�jo; Diele, Karen

Abstract

In many brachyuran species, including the mangrove crab Ucides cordatus, water-soluble chemicals (odours) emitted by adult residents trigger metamorphosis of megalopae, probably facilitating habitat selection and settlement near conspecific crab population. New field findings revealed that early benthic crab stages co-inhabit burrows of both juveniles and adults of U. cordatus which raised the question whether megalopae are also stimulated by sexually immature juveniles. Therefore, we tested in an experimental laboratory study the hypothesis that small benthic recruits and older juveniles also emit metamorphosis-stimulating odours as do conspecific adult crabs. U. cordatus megalopae were cultivated in eight conspecific odour-treatments containing seawater previously conditioned with crabs of different carapace widths (CW 0.15–5.0 cm) and in a control treatment with filtered seawater not conditioned with crabs. In all odour-treatments, including those with small immature crabs, the percentage of metamorphosed larvae was significantly higher (≥74%) and the average development was shorter (15.8–19.3 days) than in the control group, where only 30% moulted after 25.6 ± 6.6 days of megalopal development. In addition, megalopae developed 2.7 days faster when exposed to odours from young and older juveniles compared to those larvae kept in contact with odours from conspecific adults. Our results clearly demonstrate that the emission of metamorphic odours in U. cordatus is independent of size/age or sexual maturity. The responsiveness of megalopae to chemicals emitted by resident crabs of varying ages should aid the natural recovery of U. cordatus populations in areas significantly affected by size-selective fishery where only large conspecific adults are harvested.

Citation

Simith, D. D. J. D. B., Abrunhosa, F. A., & Diele, K. (2013). Chemical induction in mangrove crab megalopae. Ucides cordatus (Ucididae): Do young recruits emit metamorphosis-triggering odours as do conspecific adults?. Estuarine, Coastal and Shelf Science, 131, 264-270. https://doi.org/10.1016/j.ecss.2013.07.015

• Journal Article Type: Article
• Publication Date: 2013-10
• Deposit Date: Sep 23, 2013
• Print ISSN: 0272-7714
• Electronic ISSN: 1096-0015
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 131
• Pages: 264-270
• DOI: https://doi.org/10.1016/j.ecss.2013.07.015
• Keywords: juveniles; larval settlement; mangrove crab; metamorphosis; recruitment; sexual maturity
• Public URL: http://researchrepository.napier.ac.uk/id/eprint/6368
• Publisher URL: http://dx.doi.org/10.1016/j.ecss.2013.07.015