The Effect of Gregariousness in Cyprid Settlement Assays

Abstract

The in vitro settlement assay using cyprids of Balanus. amphitrite is an important tool in basic and applied research. The aim of this study was to quantify the effect of gregariousness within these assays, and to determine the interaction between gregariousness and container size, and settlement promoters and inhibitors. Assays with 1, 5, 10, 15, 20, and 40 cyprids in containers with a log range of surface area to volume ratios were conducted in a fully factorial design. Assays with the same range of cyprid numbers and six concentrations of the settlement promoter 3-isobutyl-1-methylxanthine (IBMX) or the inhibitor phloroglucinol were also conducted in a fully factorial design. Percentage settlement was analysed by GLM ANOVA. Significant (p < 0.05) gregarious effects were detected at > or = 5 cyprids in a well. Surface area:volume ratio had a strong effect on cyprid settlement, but this effect could be masked by overcrowding in very small wells. Gregarious interactions between only five cyprids magnified the effect of IBMX by a factor of 10, whereas phloroglucinol had no effect without gregarious interactions. The cyprid settlement bioassay is a valuable tool for basic and applied research but must be used with care.

Interaction of conspecific cues inBalanus amphitriteDarwin (Cirripedia) settlement assays: Continued argument for the single-larva assay

“…By using 1, 5, 10, 15, 20 and 40 cyprids dish 71 , Head et al (2003) showed that gregarious interactions between B. amphitrite cyprids were detectable with as few as five cyprids. Subsequent experiments employing a refined range of 1, 2, 3, 4, 5 and 10 B. improvisus or B. amphitrite cyprids dish 71 showed that gregarious effects occur with three or more larvae dish 71 in both species (Head et al 2004).…”

“…The large, irregular range used in the experiment of Clare et al (1994), the low number of densities used by Kawahara et al (1999) and Satuito et al (1997), together with the use of 20 cyprids dish 71 by Holm et al (2000) to limit gregarious effects, were used by Head et al (2003) to develop their empirical study of gregariousness in cyprid settlement assays. By using 1, 5, 10, 15, 20 and 40 cyprids dish 71 , Head et al (2003) showed that gregarious interactions between B. amphitrite cyprids were detectable with as few as five cyprids.…”

Estudio químico y evaluación de la actividad antifouling del octocoral caribeño Eunicea laciniata

“…14 El ensayo se realizó con el cirripedio cosmopolita Balanus amphitrite, especie ampliamente distribuida en el Caribe colombiano, siguiendo los métodos propuestos por varios autores, 15,16 se formó un stock de reproductores los cuales eran cirripedios adultos que se recolectaron en los sectores portuarios de Mamonal (Cartagena) y Punta de Betín (Santa Marta) desprendién-dolos suavemente de la superficie. Los cirripedios se mantuvieron en el laboratorio en acuarios con agua de mar artificial y se alimentaron con microalgas y larvas de Artemia salina.…”

Settlement and Behaviour of Marine Fouling Organisms

“…amphitrite [31] In the presence of only five cyprids, effects of settlement promoter were magnified ten times and effects of settlement inhibitor were lost.…”

“…They have been shown to respond in complex ways to a variety of cues, and in particular to the gregarious chemical cues of their own species. A laboratory-based study found that settlement of Balanus amphitrite was affected by the presence of only five other cyprids, such that the effects of a settlement promoter were magnified ten times, and of a settlement inhibitor were lost, highlighting the need to consider cue interactions [31]. A recent field-based study found that significantly more cyprids arrived on surfaces of different textures when they were treated with a gregarious chemical cue, when filmed simultaneously with an untreated control, indicating a level of behavioural control over site-encounter rates [137].…”