Cypris larva

From the evolutionary point of view, structures or mechanisms that prove a success are likely to be passed on. However, adult barnacles probably do not control the structure formation process of their cement The ability of cypris larvae to sense physical and chemical surface properties most likely vanishes after attachment and metamorphosis, for the main function of the adult is to feed and to metabolize the energy into growth and reproduction. Instead, the above observations probably suggest that the structure formation process is simply a result of water uptake increasing the effective size of the adhesive filling spaces or gaps. 

Abstract Many barnacle species are gregarious. This is an essential behavior for those species that can only reproduce by mating with a neighboring barnacle. Proximity of adult barnacles is achieved by gregarious settlement of the cypris larva. The chemical basis of this behavior was established 60 years ago, but attempts to characterize the cue to settlement met with limited success. This chapter presents evidence obtained in recent years that the cue is an a2-macroglobulin-like cuticular protein, detected by cyprids using a tactile chemical sense as they explore the substratum for a suitable settlement site. 

Fig. 22.1 Gregarious settlement of barnacle cypris larvae, (a) Cyprids approach the substratum, perhaps after encountering a waterborne cue released by adults (b) contact with substratum and onset of (c) searching behavior (d) cyprid contacts an adult conspecific and is stimulated to settle by a cuticular protein - the settlement-inducing protein complex (SIPC). The cyprid may return to the plankton at any stage of the sequence (b-d). Drawing by Jorge A. Varela Ramos...

Chan BKK, Leung PTY (2007) Antennular morphology of the cypris larvae of the mangrove barnacle Fistulobalanus albicostatus (Cirripedia Thoracica Balanomorpha). J Mar Biol Ass UK 87 913-915... 

Gibson P, Nott JA (1971) Concerning the fourth antennular segment of the cypris larva of Balanus halanoides. In Crisp DJ (ed) Fourth European marine biology symposium. Cambridge University Press, Cambridge, pp 227-236... 

Harrison PJH (1998) The nervous system and settlement of barnacle cypris larvae. PhD thesis, University of New South Wales, pp 150... 

Harrison PJH, Sandeman DC (1999) Morphology of the nervous system of the barnacle cypris larva Balanus amphitrite Darwin) revealed by light and electron microscopy. Biol Bull 197 144-158... 

Lagersson NC, Hpeg JT (2002) Settlement behaviour and antennulary biomechanics in cypris larvae of Balanus amphitrite (Crustacea Thecostraca Cirripedia). Mar Biol 141 513-526 Lagersson NC, Garm A, Hpeg JT (2003) Notes on the ultrastructure of the setae on the fourth... 

Nott JA, Foster BA (1969) On the structure of the antennular attachment organ of the cypris larva of Balanus balanoides (L.). Phil Trans Roy Soc B256 l 15-133... 

Okano K, Shimizu K, Satuito CG, Fusetani N (1998) Enzymatic isolation and culture of cement secreting cells from cypris larvae of the barnacle Megabalanus rosa. Biofouling 12 149-159... 

Prendergast GS, Zum CM, Bers AV, Head RM, Hansson LJ, Thomason JC (2009) The relative magnitude of the effects of biological and physical settlement cues for cypris larvae of the acorn barnacle, Semibalanus balanoides L. Biofouling 25 35 14... 

Figure 14.1 Length scales of the settlement stages of fouling organisms. The image of the barnacle cypris larva (kindly provided by Prof A.S. Clare) shows the paired antennules (left) referred to in Figure 14.2. The image of the larva of Hydroides elegans was kindly provided by Dr B Nedved.

Figure 14.2 Scanning electron micrograph (SEM) ofthe distal region of an antennule (A) of the cypris larva of the barnacle Balanus amphitrite, showing the attachment disk (AD) covered in nano/microvilli and several sensory...

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