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Baliga VB, Bernstein ZJ, Sundaram S, Mehta RS. Labrid cleaner fishes show kinematic convergence as juveniles despite variation in morphology. J Exp Biol 2017; 220:2787-2797. [PMID: 28515238 DOI: 10.1242/jeb.153783] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 05/14/2017] [Indexed: 11/20/2022]
Abstract
Cleaning, a dietary strategy in which mucus or ectoparasites are removed and consumed off other taxa, is performed facultatively or obligately in a variety of species. We explored whether species in the Labridae (wrasses, parrotfishes) of varying ecological specialization employ similar mechanisms of prey capture. In investigating feeding on attached prey among juveniles of 19 species of wrasses, we found that patterns of biting in wrasses are influenced by the interaction between the maxilla and a feature of the premaxilla which we term the maxillary crest. Premaxillary motion during biting appears to be guided by the relative size of the crest. In many cases, this results in a 'premaxillary bite' wherein the premaxillae rapidly move anteroventrally to meet the lower jaws and deliver a protruded bite. Cleaners in the Labrichthyini tribe, however, exhibited reduced or absent maxillary crests. This coincided with a distinct kinematic pattern of prey capture in these labrichthyine cleaners, coupled with some of the fastest and lowest-excursion jaw movements. Although evidence of kinematic specialization can be found in these labrichthyines (most notably in the obligate cleaners in Labroides), we found that facultative cleaners from other lineages similarly evolved reductions in excursions and timing. Convergence in feeding kinematics is thus apparent despite varying degrees of cleaning specialization and underlying morphological features.
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Affiliation(s)
- Vikram B Baliga
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Ze'ev J Bernstein
- Pacific Collegiate School, 3004 Mission Street, Santa Cruz, CA 95060, USA
| | - Shivani Sundaram
- Monta Vista High School, 21840 McClellan Rd, Cupertino, CA 95014, USA
| | - Rita S Mehta
- Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California Santa Cruz, 100 Shaffer Road, Santa Cruz, CA 95060, USA
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Van Wassenbergh S, Joris I, Desclée M, Liew HJ, De Boeck G, Adriaens D, Aerts P. Kinematics of mouthbrooding in Oreochromis niloticus (Cichlidae). ACTA ACUST UNITED AC 2016; 219:1535-41. [PMID: 27207955 DOI: 10.1242/jeb.131631] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 03/02/2016] [Indexed: 11/20/2022]
Abstract
Many species from several different families of fishes perform mouthbrooding, where one of the sexes protects and ventilates the eggs inside the mouth cavity. This ventilation behaviour differs from gill ventilation outside the brooding period, as the normal, small-amplitude suction-pump respiration cycles are alternated with actions including near-simultaneous closed-mouth protrusions and high-amplitude depressions of the hyoid. The latter is called churning, referring to its hypothetical function in moving around and repositioning the eggs by a presumed hydrodynamic effect of the marked shifts in volume along the mouth cavity. We tested the hypothesis that churning causes the eggs located posteriorly in the mouth cavity to move anteriorly away from the gill entrance. This would prevent or clear accumulations of brood at the branchial basket, which would otherwise hinder breathing by the parent. Dual-view videos of female Nile tilapias (Oreochromis niloticus) during mouthbrooding showed that churning involves a posterior-to-anterior wave of expansion and compression of the head volume. Flow visualisation with polyethylene microspheres revealed a significant inflow of water entering the gill slits at the zone above the pectoral fin base, followed by a predominantly ventral outflow passing the ventrolaterally flapping branchiostegal membranes. X-ray videos indicated that particularly the brood located close to the gills is moved anteriorly during churning. These data suggest that, in addition to mixing of the brood to aid its oxygenation, an important function of the anterior flow through the gills and buccal cavity during churning is to prevent clogging of the eggs near the gills.
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Affiliation(s)
- Sam Van Wassenbergh
- Department of Biology, University of Antwerp, Universiteitsplein 1, Antwerpen 2610, Belgium Department of Biology, Ghent University, K.L. Ledeganckstraat 35, Gent 9000, Belgium
| | - Iris Joris
- Department of Biology, University of Antwerp, Universiteitsplein 1, Antwerpen 2610, Belgium
| | - Mathieu Desclée
- Department of Biology, University of Antwerp, Universiteitsplein 1, Antwerpen 2610, Belgium
| | - Hon Jung Liew
- Department of Biology, University of Antwerp, Universiteitsplein 1, Antwerpen 2610, Belgium Institute of Tropical Aquaculture, Universiti Malaysia Terengganu, Kuala Terengganu, Terengganu 21030, Malaysia
| | - Gudrun De Boeck
- Department of Biology, University of Antwerp, Universiteitsplein 1, Antwerpen 2610, Belgium
| | - Dominique Adriaens
- Department of Biology, Ghent University, K.L. Ledeganckstraat 35, Gent 9000, Belgium
| | - Peter Aerts
- Department of Biology, University of Antwerp, Universiteitsplein 1, Antwerpen 2610, Belgium Department of Movement and Sport Sciences, Ghent University, Watersportlaan 2, Gent 9000, Belgium
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