Larval development of the intertidal barnacles Chthamalus stellatus and Chthamalus montagui

. This distribution pattern was considered to result from upwellingfavourable wind conditions, creating fronts along the shelf in which the cyprids become concentrated. Cyprid vertical migration, in association with current vertical shear and onshore movement of fronts during upwelling-relaxation periods, may be the mechanisms returning cyprids to the coast to settle. The regularity of these events in the region falls within the period of cyprid viability.

Section: Discussionmentioning

confidence: 99%

Horizontal and vertical distribution of cirripede cyprid larvae in an upwelling system off the Portuguese coast

Santos¹,

Santos²,

Conway³

2007

“…For larval classification the following descriptions were used: Norris & Crisp (1953) for Balanus perforatus, Pyefinch (1948) for B. crenatus, Burrows et al (1999) for Chthamalus montagui and C. stellatus, and Bassindale (1936) and Pyefinch (1948) for Verruca stroemia. In estimating larval release we counted Nauplius I and II stages.…”

Section: Methodsmentioning

confidence: 99%

Timing of larval release by three barnacles from the NW Iberian Peninsula

Macho¹,

Molares

Vázquez³

2005

The timing of larval release and the cues that control these rhythms (tidal, diurnal, or lunar cycles) were studied over a 2 mo period in the cirripeds Pollicipes pollicipes, Balanus spp. and Chthamalus spp., occurring on an exposed rocky shore in NW Spain. All of them showed rhythms of larval release, but the rhythms were different in each species. Chthamalus spp., which principally inhabit the upper intertidal zone, released their larvae mainly during diurnal high tides at the time of new and full moons. Larval release was greater during the afternoon than during the morning, because the amplitude of afternoon high tides was significantly higher than that of morning high tides. P. pollicipes larvae were released at morning high tide during waning moon and, to a lesser extent, during full moon. Nauplii of Balanus spp. were released during new and waning moons; almost no release occurred during full moon, and no larvae were found during the waxing moon, mainly during diurnal high tides. P. pollicipes and Balanus spp. usually began to release larvae after sunrise, which may be the factor inducing synchrony. In contrast, Chthamalus spp. released larvae at any time of day, but always coinciding with high tide, indicating that seawater may be the cue that triggers larval release in this species. Although larval release should occur during safe periods (e.g. night-time) in species such as those under study, with small unprotected colored larvae that are visible to predators, almost no larvae of any of the 3 cirripeds were found at night. Cirriped Nauplius I larvae respond positively to light, allowing larvae to travel upwards in the water column, away from congeners that could incidentally ingest their own larvae, and are transported offshore away from predators, which are more abundant close to the shore. At night this photopositive behavior does not take place, and thus the synchrony in the emission of larvae during daytime induces larval aggregation, which may increase larval survival because of the swamp effect over predators.

“…The processes controlling the distribution patterns of C , stellatus and C. montagui are as yet unknown. There are some differences between the 2 species in settled cyprid density relative to metan~orph abundance ) and larval development time (Burrows et al 1999). Studies which compare sympatric larval settlement in the field between these species have been hampered because, although minute structural differences in the cyprid carapace have been reported in C. stellatus and C. montagui (Jensen et al 1994), no diagnostic tool for species identification as cyprids has been available.…”

Section: Introductionmentioning

confidence: 99%

“…Carapace length has been suggested as a method of distinguishing between larvae of Chthamalus stellatus and C, montagui from field samples (Burrows 1988, Burrows et al 1999). The present work investigated size as a useful means of identifying C. stellatus and C. montagui cyprids from field samples collected at different dates in south and west Ireland.…”

Section: Introductionmentioning

confidence: 99%

Verification of cyprid size as a tool in the identification of two European species of Chthamalus barnacles using mtDNA-RFLP analysis

Power¹,

Piyapattanakorn²,

O’Riordan³

et al. 1999

Adult barnacles of Chthamalus stellatus and Chthamalus montaguj were collected in August 1998, from Garrettstown Co. Cork and Kdkee Co. Clare, In southwest and west Ireland, respectively Attached cypris larvae were collected during the settlement season of C. stellatus and C. montagui, on 2 shores in Co. Cork and 1 shore on Clare Island. Co. Mayo in west Ireland. Cypnd collections were made during either August or September, in 1992, 1994 and 1998 and all cyprids were measured along their carapace length. Size-frequency histograms were produced for each sampling occasion Total DNA was extracted and the COI-CO11 mitochondr~al genes were PCR amplified, both from selected adults and cypnds of each species collected in 1998. Composite haplotypes, produced by digesting PCR products with the restriction endonucleases Tag1 and RsaI, showed clear identification between the 2 species as adults and larvae. Of the 68 cyprids examined, those measuring 525 pm and under were found to have RFLP profiles corresponding with C. montagui adults, while those of 550 pm and larger were found to match C. stellatus adults. The findings verify previous length-frequency analys~s Carapace length is a n important character in the identification of C. stellatus and C. montagui cypnds The PCR primers developed during this study will also amplify DNA from 4 other species of acorn barnacle