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Ecological traits of Caribbean sea anemones and symbiotic crustaceans


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In Caribbean coral reefs, many crustacean species associate with sea anemones, but only a few are anemone symbionts. We examined several ecological traits of 3 anemone species (Bartholomea annulata, Condylactis gigantea, Lebrunia danae) and their crustacean symbionts (6 species) on a coral reef at Puerto Morelos, Mexico. On average, C. gigantea was the largest and B. annulata the most abundant of the 3 anemone species. Season did not affect the density distribution of any species, whereas reef zone (back reef, fore reef, reef channels) significantly affected density and mean size of B. annulata and C. gigantea, but only density of L. danae. The probability of harboring crusta ceans increased with anemone size in all species, but varied with reef zone and season in B. annulata only. These patterns may be due to different microhabitat requirements, reproductive strategies, or photosynthetic plasticity of dinoflagellate endosymbionts among hosts, and different flow regimes among reef zones. Alpheus armatus and Ancylomenes pedersoni were strongly associated with B. annulata, and Periclimenes rathbunae with L. danae. Thor amboinensis and Mithraculus cinctimanus occurred more often in C. gigantea, while P. yucatanicus was more evenly associated with the 3 hosts. Only Ancylomenes pedersoni and T. amboinensis occurred in conspecific groups more often than expected by chance. Commensal complexes of up to 3 symbiont species occurred in all host species, with symbionts that typically used different parts of the host coexisting more frequently. These results provide a baseline to assess the potential influence of local and global anthropogenic stressors on anemone-crustacean symbioses.
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Mar Ecol Prog Ser
Vol. 470: 55–68, 2012
doi: 10.3354/meps10030 Published December 6
Coral reefs support the highest biodiversity of all
marine ecosystems, with invertebrates contributing
dominantly to this condition (Reaka et al. 2008). In
the complex community networks typical of coral
reefs, an important ecological role is played by
many invertebrates that may serve as ‘habitat
providers’ (i.e. species that offer structure or sub-
strate that other species may live in or on). Habitat
providers are ubi quitous and include numerous spe-
cies of sponges, hard and soft corals, tube-dwelling
polychaetes, asci dians, echinoderms, molluscs, and
sea anemones. Equally diverse are the organisms
that live in or on habitat providers, which include a
vast array of invertebrates and fishes (review in
Glynn & Enochs 2011).
Organisms that associate with habitat providers
(‘hosts’) may obtain a variety of benefits, including
physical shelter from predation, camouflage, stabil-
ity, range expansion, or advantageous positioning.
For example, the nematocyst-armed tentacles of sea
© Inter-Research 2012 ·*Email:
Ecological traits of Caribbean sea anemones and
symbiotic crustaceans
P. Briones-Fourzán1,*, M. Pérez-Ortiz2, F. Negrete-Soto1, C. Barradas-Ortiz1,
E. Lozano-Álvarez1
1Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología,
Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo 77580, Mexico
2Posgrado en Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, México,
Distrito Federal 04360, Mexico
ABSTRACT: In Caribbean coral reefs, many crustacean species associate with sea anemones, but
only a few are anemone symbionts. We examined several ecological traits of 3 anemone species
(Bartholomea annulata, Condylactis gigantea, Lebrunia danae) and their crustacean symbionts
(6 species) on a coral reef at Puerto Morelos, Mexico. On average, C. gigantea was the largest and
B. annulata the most abundant of the 3 anemone species. Season did not affect the density distri-
bution of any species, whereas reef zone (back reef, fore reef, reef channels) significantly affected
density and mean size of B. annulata and C. gigantea, but only density of L. danae. The probability
of harboring crusta ceans increased with anemone size in all species, but varied with reef zone and
season in B. annulata only. These patterns may be due to different microhabitat requirements,
reproductive strategies, or photosynthetic plasticity of dinoflagellate endosymbionts among hosts,
and different flow regimes among reef zones. Alpheus armatus and Ancylomenes pedersoni were
strongly associated with B. annulata, and Periclimenes rathbunae with L. danae. Thor amboinen-
sis and Mithraculus cinctimanus occurred more often in C. gigantea, while P. yucatanicus was
more evenly associated with the 3 hosts. Only Ancylomenes pedersoni and T. amboinensis
occurred in conspecific groups more often than expected by chance. Commensal complexes of up
to 3 symbiont species occurred in all host species, with symbionts that typically used different
parts of the host coexisting more frequently. These results provide a baseline to assess the poten-
tial influence of local and global anthropogenic stressors on anemone−crustacean symbioses.
KEY WORDS: Symbiosis · Coral reef · Mexico · Commensal complex · Puerto Morelos
Resale or republication not permitted without written consent of the publisher
Mar Ecol Prog Ser 470: 55–68, 2012
anemones provide protection from predation to many
crustaceans (Fautin et al. 1995, Wirtz 1997, Khan et
al. 2004) that acquire immunity from the toxic com-
pounds produced by their hosts through a process
known as acclimation (Levine & Blanchard 1980,
Crawford 1992, Giese et al. 1996). The general term
‘crustacean associates’ refers to any crustacean
found in, on, or very close to an anemone, but such
crustaceans can be categorized into 2 types: ‘facul -
tative associates’, i.e. crustaceans that are primarily
free-living but may briefly associate with anemones,
and ‘symbionts’, i.e. crustaceans wherein the asso -
ciation with the host is not random or occasional, but
long-term (Ross 1983, Gwaltney & Brooks 1994,
Cala do et al. 2002).
In the wider Caribbean region, some field studies
have focused on the abundance, distribution, or pop-
ulation dynamics of anemones without regard to
their symbionts (e.g. Sebens 1976, Barrios-Suárez et
al. 2002, Herrera-Moreno & Betancourt-Fernández
2002, Nelsen 2008). Other studies have mainly fo -
cused on ecological traits of the crustacean sym-
bionts, such as degree of host specificity (e.g. Knowl-
ton 1980, Gwaltney & Brooks 1994), distribution
patterns (e.g. Hayes & Trimm 2008, Silbiger & Chil-
dress 2008), or demography and behavior (e.g.
Mahnken 1972, Sargent & Wagenbach 1975, Patton
1979, Williams & Bunkley-Williams 2000, Huebner &
Chadwick 2012a). Others have contrasted ecological
traits of anemones with those of their crustacean
symbionts, but with emphasis on a particular host
species (e.g. Herrnkind et al. 1976, Stanton 1977,
Huebner & Chadwick 2012b) or one or a few selected
symbiont species (e.g. Mahnken 1972, Nizinski 1989,
Silbiger & Childress 2008). However, be cause most
crustacean symbionts of Carib bean anemones are
host-generalists (e.g. see Silbiger & Childress 2008),
their abundance and distribution at the local scale
may depend to some extent on the ecological traits of
multiple host anemone species, their use of space
provided by the host, and intra- and interspecific
interactions with other crustacean associates.
To provide some insight into these issues, we
examined several ecological traits of multiple species
of host anemones and their crustacean symbionts in
one of the most intensely studied Caribbean coral
reef systems in Mexico, the Puerto Morelos coral reef
system (PMCR) (Rodríguez-Martínez 2008). Nearly
20 yr of monitoring of environmental variables and
ecological features of these coral reef and sea grass
communities provides continuously updated infor-
mation on environmental characteristics prevailing
in different parts of the PMCR (e.g. Ruiz-Rentería
et al. 1998, Jordán-Dahlgren & Rodríguez-Martínez
2003, Coronado et al. 2007, Rodríguez-Martínez et al.
2010, van Tussenbroek 2011).
Among the 13 species of sea anemones registered
in the PMCR (González-Muñoz 2009), 3 actiniarians
widely known as hosts for crustaceans are particu-
larly ubiquitous: the corkscrew anemone Bartho lo -
mea annulata (Family Aiptasiidae), the giant ane -
mone Condylactis gigantea (Actiniidae), and the
branching anemone Lebrunia danae (Aliciidae). In
the present study, we examine several ecological
traits of these 3 host anemone species, and of the full
array of their crustacean symbionts. We were partic-
ularly interested in examining the density and size
distribution of each host species in distinct reef envi-
ronments, and the degree to which these traits varied
on a seasonal basis. Our aim was to assess the rela-
tive importance of these anemone species in provid-
ing habitat for crustacean symbionts in reef zones
with different environmental features.
Study area
The PMCR (centered at 20° 51’ N, 86° 53’ W) is
located near the town of Puerto Morelos on the NE
coast of the Yucatan Peninsula (state of Quintana
Roo, Mexico). It is an extended fringing reef com-
posed of a series of reef patches differing in size and
structural complexity (Fig. 1). The reef is separated
from the shoreline by a narrow (~500 to 1500 m in
width) and shallow (<5 m in depth) reef lagoon char-
acterized by calcareous sand stabilized by sea grass
meadows (Ruiz-Rentería et al. 1998). The PMCR has
a well-developed back reef and reef crest, and a
relatively flat fore reef that descends gradually to
20−25 m into an extensive sand platform (Jordán-
Dahlgren 1989, Rodríguez-Martínez et al. 2010). The
back reef is dominated by the scleractinians Acro -
pora palmata and Montastraea annularis, and varies
from shallow (2 to 3 m) protected flat areas, to deeper
(5 to 7 m), relatively more exposed areas with higher
relief. The fore reef also varies from areas of hard
substrate with a relatively gentle slope, colonized by
many small scleractinian colonies, gorgonians, and
sponges, to high relief areas where large scleracti -
nians dominate (Jordán-Dahlgren & Rodríguez-Mar -
tínez 2003). A detailed study on the physical oceano -
graphy of this coral reef system found that the
exchange of water between the reef lagoon and the
adjacent ocean is mainly driven by the circulation
Briones-Fourzán et al.: Caribbean anemones and symbiotic crustaceans
induced by surface waves overtopping the reef and
spilling water into the lagoon, with the water eventu-
ally leaving the lagoon through the reef channels
(Coronado et al. 2007).
Sampling design
To account for the local hydrodynamic regime, and
for differences in structural complexity as well as
environmental gradients along and across the reef
tract, we established 3 replicate fixed sites in each of
3 reef zones: back reef, fore reef, and reef channels
(Fig. 1). Each site measured 50 × 50 m (i.e. 0.25 ha)
and was delineated with flag tags. The back-reef
sites (1.8 to 2.0 m depth) were located along the lee-
ward side of a large, elongated reef patch that
extends for ~6 km (Fig. 1). The fore-reef sites (8.0 to
10.2 m depth) were located on the exposed side of
3 relatively well-developed reef patches. The reef
channel sites (5.0 to 7.0 m depth) were located on
relatively exposed, deeper areas of the back reef
adjacent to 3 reef channels (Fig. 1).
Using SCUBA, we surveyed the entire area of each
site for individuals of Bartholomea annulata, Condyl -
actis gigantea, and Lebrunia danae during 4 consec-
utive seasons starting in the spring of 2007 (spring:
12 April to 4 May; summer: 10 to 30 September;
autumn: 21 November to 4 December 2007; winter:
13 February to 3 March 2008). All surveys were con-
ducted between 10:00 and 13:00 h. Within each site,
we counted all anemones, and measured the length
(L) and width (W) of the tentacle crown of each indi-
vidual with a metal ruler (±0.5 cm) to estimate the
tentacle crown surface area (TCSA = π× 0.5 L ×
0.5 W; Hattori 2002). We also counted and identified
in situ the crustaceans associated with each ane -
mone, and recorded their positions relative to the
host (‘on host’: on the tentacle crown; ‘under host’:
under the tentacle crown; ‘near host’: on the sub-
strate surrounding the anemone, within a radius of
~10 cm).
Statistical analyses
Variability in anemone density and size (TCSA)
We subjected the anemone density data (number of
individuals 0.25 ha−1) to a factorial repeated-mea-
sures ANOVA (RM-ANOVA). The main (fixed) fac-
tors were anemone species (AS, with 3 levels) and
reef zone (RZ, with 3 levels: back-reef, reef channels,
and fore-reef, and 3 replicate sites per level). Time
(T, with 4 levels corresponding to the 4 seasons) was
the repeated measure. The data were previously
transformed to ln(n + 1) to meet the assumption of
homogeneity of variances as assessed with Levene
tests. In repeated-measures studies, the data may be
auto-correlated (i.e. non-independent) across times.
To overcome this problem, we assessed the degree to
which the assumption of sphericity was violated with
a Mauchly’s test and, if necessary, adjusted the
degrees of freedom of T and its residuals with the
Huynh-Feldt correction (Howell 2002).
Because the 3 anemone species were not present
on all replicate sites of each zone at all seasons
(precluding the use of RM-ANOVA), the data on
size (TCSA in cm2) for each species were pooled by
Fig. 1. The Puerto Morelos coral reef system. Black struc-
tures = coral reef patches. Symbols = location of 9 fixed sam-
pling sites (q: back-reef site; s: fore-reef site; n: reef-chan-
nel site). Inset: location of Puerto Morelos (arrow) in Mexico
Mar Ecol Prog Ser 470: 55–68, 2012
reef zone and subjected to a factorial ANOVA to
test the effects of AS and RZ on mean size of
anemones (Underwood 1981). The data were previ-
ously transformed to ln(TCSA) to increase homo-
geneity of variances, as assessed with Levene tests.
Distribution of crustaceans among host anemones
We used 3 logistic regression analyses (1 per ane -
mone species) to test the effects of size (TCSA, conti -
nuous factor), time, and reef zone (categorical factors
with 4 and 3 levels, respectively) on their prob -
abilities of harboring crustaceans (Quinn & Keough
2002). The binary response variable was the absence
or presence of at least 1 crustacean associate. We
then used a simple linear regression to examine the
relationship between TCSA and the number of crus-
tacean associates.
To examine the distribution of crustaceans among
conspecific hosts, we computed the mean number of
crustaceans per anemone (and the corresponding
variance), and subjected the count data to a χ2good-
ness-of-fit test to a Poisson (random) distribution. If
the test was significant, we further subjected the data
to a χ2goodness-of-fit test to a negative binomial dis-
tribution. Finally, we categorized the crustaceans into
symbionts and facultative associates based on previ-
ous knowledge on the types of habitats used by each
species (e.g. Chace 1972, Wagner 1990, Monroy-
Velázquez 2000, Briones-Fourzán & Lozano-Álvarez
2002, Silbiger & Childress 2008), and used exclusively
the symbiont species in the following analyses.
Density of crustacean symbionts, affinity for hosts,
and use of space provided by host
The density of symbionts (number of individuals
0.25 ha−1) was examined with a factorial RM-
ANOVA. The main (fixed) factors were symbiotic
crustacean species (CS, with 6 levels corresponding
to the 6 symbiotic species) and RZ. T was the re -
peated measure. The data were previously trans-
formed to ln(n + 1) to increase homogeneity of vari-
ances, and the degree to which the assumption of
sphericity was violated was assessed with Mauchly’s
For each symbiont species, we used separate χ2
goodness-of-fit tests to compare the proportions of
individuals distributed among the 3 host species and
the 3 positions relative to the host. Seasonal vari -
ability in these traits was separately examined with a
3 × 4 contingency table (3 levels for the correspond-
ing categorical factor × 4 seasons).
Conspecific groups and commensal complexes
To assess the tendency of symbionts to form
groups, we computed the number of conspecific sym-
bionts that were alone or in groups of 2, 3, etc., in the
same host, and compared the frequency data with a
truncated Poisson (random) distribution using χ2
(Cohen 1960). We then computed all commensal
complexes (2 or more species of symbionts coexisting
in the same host) for each host species, and explored
how coexisting species used the space provided by
the host (e.g. Stanton 1977).
Host anemones
Anemone density and size
The data on anemone density did not violate the as-
sumption of independent samplings across time
(Mauchly test, W= 0.863, χ25= 2.456, p = 0.783;
Huynh-Feldt correction = 1). Density varied signifi-
cantly with AS and T, and there were interaction ef-
fects between AS × RZ and T × RZ (Table 1). The over-
all density (all means ± SE) of Bartholomea annulata
(23.2 ± 3.1 ind. 0.25 ha−1) was almost twice as high as
that of Lebrunia danae (13.5 ± 3.0 ind. 0.25 ha−1) and
over 4 times as high as that of Condylactis gigantea
(5.3 ± 0.9 ind. 0.25 ha−1). In particular, the density of
Effect df MS Fp
Intercept 1 480.425 179.922 <0.001
AS 2 28.505 10.675 0.001
RZ 2 1.603 0.600 0.559
AS × RZ 4 12.250 4.588 0.010
Error 18 0.504
T 3 0.305 4.130 0.010
T × AS 6 0.104 1.415 0.226
T × RZ 6 0.247 3.343 0.007
T × AS × RZ 12 0.041 0.550 0.871
Error 54 0.014
Table 1. Bartholomea annulata, Condylactis gigantea, and
Lebrunia danae. Repeated-measures ANOVA of anemone
density (ln [n + 1] 0.25 ha−1) with anemone species (AS) and
reef zone (RZ; back reef, reef channels, fore reef) over time
(T; spring, summer, autumn, and winter)
Briones-Fourzán et al.: Caribbean anemones and symbiotic crustaceans
B. annulata was highest in the reef channels (35.9 ±
1.2 ind. 0.25 ha−1, averaged across seasons; Fig. 2a),
while densities of C. gigantea (1.2 ± 0.2 ind. 0.25 ha−1)
and L. danae (1.3 ± 0.1 ind. 0.25 ha−1) were lowest in
the reef channels and on the back reef, respectively
(Fig. 2b,c). The density distribution of each species by
reef zone remained rather stable over time (T × AS ×
RZ; Table 1). However, within each reef zone during
any season, there was considerable variation in den-
sity among replicate sites, especially for C. gigantea
on the fore reef (where this species was generally rare
in 2 of the 3 sites) and L. danae on the back reef
(Fig. 3), indicating a rather patchy distribution.
The overall range in TCSA was 3.1 to 380.1 cm2for
Bartholomea annulata, 2.4 to 276.5 cm2for Lebrunia
danae, and 7.1 to 452.4 cm2for Condylactis gigantea.
Mean TCSA (averaged across seasons) varied signif-
icantly among species (F2,27 = 31.581, p < 0.001) and
reef zones (F2, 27 = 20.330, p < 0.001), with a signifi-
cant interaction effect between these 2 variables
(F4,27 = 8.714, p < 0.001). The TCSA (all means ± SE)
of C. gigantea (109.2 ± 17.4 cm2) was twice as large
as those of L. danae (56.9 ± 4.1 cm2) or B. annulata
(50.6 ± 4.1 cm2). However, the TCSA of B. annulata
was significantly larger on the fore reef (66.1 ±
4.1 cm2) than in the reef channels (46.3 ± 4.8 cm2) or
on the back reef (39.2 ± 3.3 cm2) (Fig. 4), and the
TCSA of C. gigantea decreased significantly from the
fore reef (173.0 ± 27.6 cm2) to the back reef (105.0 ±
5.0 cm2) to the reef channels (49.5 ± 2.7 cm2; Fig. 4),
whereas the TCSA of L. danae did not vary signifi-
cantly with reef zone (Fig. 4).
The population size distribution of each anemone
species in increments of 25 cm2TCSA revealed that,
Fig. 2. Bartholomea annulata, Condylactis gigantea, and
Lebrunia danae. Density (mean ± SE) of (a) B. annulata, (b)
C. gigantea, and (c) L. danae in 3 reef zones (back reef, reef
channels, fore reef, 3 replicate sites per zone) at 4 seasons
(spring, summer, and autumn 2007, and winter 2008)
Fig. 3. Bartholomea annulata, Condylactis gigantea, and
Lebrunia danae. Coefficient of variation (%) of anemone
density among replicate sites for each reef zone and season
Fig. 4. Bartholomea annulata, Condylactis gigantea, and
Lebrunia danae. Size (tentacle crown surface area, TCSA,
mean ± SE) measured in the back reef, reef channels, and
fore reef zones (3 replicate sites per zone). Similar letters in
columns denote statistically similar means
Mar Ecol Prog Ser 470: 55–68, 2012
for Bartholomea annulata, the mode increased from
the back reef (25 cm2) to the reef channels (25 to
50 cm2) to the fore reef (50 to 75 cm2; Fig. 5a). Lebru-
nia danae exhibited a single mode in the size class 25
to 50 cm2in all 3 reef zones, albeit more markedly in
the back reef (Fig. 5b). In contrast, Condylactis
gigantea exhibited a multimodal size distribution in
all 3 reef zones (Fig. 5c).
Distribution of crustaceans among host anemones
Across the study period, crustaceans were present
in 72.8% of individuals of Bartholomea annulata (n =
835), 70.7% of Condylactis gigantea (n = 191), and
27.2% of Lebrunia danae (n = 486). In B. annulata,
the probability of harboring crustaceans increased
significantly with TCSA, and was also affected by
reef zone and season (Table 2). In particular, the
probability was significantly lower in the reef chan-
nels (Table 2). By contrast, the only factor signifi-
cantly (positively) affecting the probability of finding
crustaceans in C. gigantea and L. danae was TCSA
(Table 2).
Per individual anemone,Bartholomea annulata and
Condylactis gigantea harbored from 0 to 7 individual
crustaceans, and Lebrunia danae from 0 to 5. In all
3 host species, there was a significant (all p-values
<0.001) but rather weak relationship between num-
ber of crustaceans and TCSA (B. annulata: r2= 0.115,
n = 825; C. gigantea: r2= 0.173, n = 187; L. danae:
r2= 0.055, n = 484). The distribution of crustaceans
among conspecific hosts differed significantly from
random in all cases (Table 3). In B. annulata, the
count data were dominated by solitary crustaceans
(i.e. 1 per host) and the mean was greater than the
variance, indicating under-dispersion (Table 3). By
contrast, in C. gigantea and L. danae, the variance
was greater than the mean, indicating over-disper-
sion, and the negative binomial distribution fitted the
distribution of crustaceans well (Table 3).
Diversity of crustacean associates
In total, we found 1371 individual crustaceans on
these anemones, of which 1283 (93.8%) belonged to
6 species of symbionts: the alpheid shrimp Alpheus
armatus, the palaemonid shrimps Ancylomenes ped-
ersoni (previously known as Periclimenes pedersoni;
Okuno & Bruce 2010), Periclimenes yucatanicus and
P. rathbunae, the hippolytid shrimp Thor amboinen-
sis, and the majid crab Mithraculus cinctimanus
(Table 4). The rest (86 individuals, 6.2% of the total)
belonged to 9 species of facultative associates (the
shrimps Stenopus hispidus, Brachycarpus biungui -
culatus, and Cinetorhynchus rigens, and the crabs
Stenorhynchus seticornis, Mithraculus sculptus, Mi -
thraculus forceps, Mithrax pilosus, Mithrax sp., and
Macrocoeloma trispinosum; Table 4).
Crustacean symbionts
Density and distribution of crustacean symbionts
Data on the density of crustacean symbionts did not
violate the assumption of independent samplings
across time (Mauchly test, χ25= 10.267, p = 0.067;
Huynh-Feldt correction = 1). Density varied signifi-
cantly with CS and T, and there was a significant in -
Fig. 5. Bartholomea annulata, Lebrunia danae, and Condy-
lactis gigantea. Size distribution (tentacle crown surface
area, TCSA) of individuals of (a) B. annulata, (b) L. danae,
and (c) C. gigantea in the back reef, reef channels, and fore
reef zones. Numbers on the x-axis: end points of intervals.
Numbers in (): sample size
Briones-Fourzán et al.: Caribbean anemones and symbiotic crustaceans
ter action effect between these 2 variables (Table 5).
On average, Alpheus armatus was much more abun-
dant than the other 5 symbionts. All interaction effects
with RZ were non-significant (Table 5), indicating
that the relative density of each symbiont by reef zone
remained rather stable over time. Thus, by reef zone,
the highest densities corresponded to Alpheus arma-
tus on the back reef and in reef channels, while the
lowest densities correspon ded to the 3 palaemonids
(Ancylo menes pedersoni, Periclimenes
yuca tanicus, and P. rathbunae) on the
back reef, and to P. yucatanicus in the
reef channels (Fig. 6a).
Degree of affinity for host and use of
space provided by host
Alpheus armatus and Ancylomenes
pedersoni exhibited a high affinity for
Bartholomea annulata (Fig. 6b), but
the former showed a strong tendency
to occur under the host, whereas the
latter was more often found on or
near the host (Fig. 6c). Periclimenes
rathbunae showed a high affinity for
Lebrunia danae (Fig. 6b) and tended
to occur on or under the host (Fig. 6c).
Thor amboinensis and Mithraculus
cinctimanus were mostly associated
with Condylactis gigantea, but many
were also found with L. danae or
B. annulata (Fig. 6b). These 2 sym-
bionts, in particular M. cinctimanus,
occur red more often under the host
(Fig. 6c). P. yucatanicus exhibited a
rather low de gree of host affinity,
with 41% individuals associated with
C. gigantea, 39% with L. danae, and
20% with B. annulata (Fig. 6b), and
show ed a similar pattern of host space
use as in Ancylomenes pedersoni,
with most individuals occurring on or
near the host (Fig. 6c).
Season did not affect the degree of
host affinity for any symbiont (contin-
gency table analyses, range in p-val-
ues: 0.109 to 0.918), or the pattern of
host space use for Mithraculus cinc -
timanus (χ26= 8.874, p = 0.181), Peri-
climenes rathbunae (χ26= 8.656, p =
0.194), or P. yucatanicus (χ26= 11.659,
p = 0.07). However, there was signifi-
cant seasonal variation in host space use by Alpheus
armatus (χ26= 40.190, p < 0.001), Ancylomenes ped-
ersoni (χ26= 18.726, p = 0.005), and Thor amboinensis
(χ26= 25.397, p < 0.001). In Alpheus armatus, this
variability reflected changes in the proportions of
individuals located under or near the host, and in
Ancylomenes pedersoni and T. amboinensis, it
reflected changes in the proportions of individuals
located near or on the host.
Effect Estimate ± SE Wald df p Odds ratio
statistic (95% CI)
B. annulata
Size 0.026 ± 0.004 48.689 1 < 0.001 1.03 (1.03−1.05)
Zone: Back reef 0.189 ± 0.142 1.775 1 0.183 1.21 (0.91−1.59)
Reef channels −0.383 ± 0.124 9.556 1 0.002 0.68 (0.53−0.87)
Season: Spring 0.071 ± 0.206 0.118 1 0.731 1.07 (0.72−1.61)
Summer 0.435 ± 0.197 4.862 1 0.027 1.54 (1.05−2.27)
Autumn −0.358 ± 0.162 4.861 1 0.027 0.70 (0.51−0.96)
C. gigantea
Size 0.011 ± 0.004 9.386 1 0.002 1.01 (1.00−1.02)
Zone: Back reef −0.059 ± 0.294 0.040 1 0.841 0.94 (0.53−1.68)
Reef channels −0.759 ± 0.456 2.767 1 0.096 0.47 (0.19−1.14)
Season: Spring 0.428 ± 0.437 0.958 1 0.328 1.53 (0.65−3.61)
Summer 0.132 ± 0.488 0.073 1 0.786 1.14 (0.44−2.97)
Autumn −0.549 ± 0.406 1.823 1 0.177 0.58 (0.26−1.28)
L. danae
Size 0.010 ± 0.003 12.867 1 < 0.001 1.01 (1.00−1.02)
Zone: Back reef 0.252 ± 0.386 0.426 1 0.514 1.29 (0.60−2.74)
Reef channels 0.012 ± 0.229 0.003 1 0.958 1.01 (0.65−1.59)
Season: Spring −0.276 ± 0.371 0.551 1 0.458 0.76 (0.37−1.57)
Summer 0.538 ± 0.366 2.160 1 0.142 1.71 (0.84−3.51)
Autumn 0.239 ± 0.327 0.534 1 0.465 1.27 (0.67−2.41)
Table 2. Bartholomea annulata, Condylactis gigantea, and Lebrunia danae.
Estimates of separate logistic regression analyses testing effects of size (tenta-
cle crown surface area, TCSA in cm2), reef zone (back reef, reef channels, and
fore reef; reference level: fore reef), and season (reference level: winter) on the
probability of finding at least 1 crustacean associate on each species of host
Host anemone species
B. annulata C. gigantea L. danae
Total N 835 191 486
N with crustaceans (%) 608 (72.8) 135 (70.7) 132 (27.2)
Mean no. of crustaceans 1.04 1.70 0.37
Variance 0.83 3.26 0.52
Variance/Mean 0.798 1.918 1.475
Goodness of fit to χ24= 80.10, χ24= 49.46, χ22= 16.92,
Poisson distribution p < 0.001 p < 0.001 p < 0.001
Type of distribution Underdispersed Overdispersed Overdispersed
Goodness of fit to χ26= 8.69, χ23= 1.795,
negative binomial distr. p = 0.192 p = 0.578
Table 3. Bartholomea annulata, Condylactis gigantea, and Lebrunia danae.
Statistics and goodness-of-fit tests for types of distributions of crustaceans
among individuals of each host anemone species
Mar Ecol Prog Ser 470: 55–68, 2012
Conspecific groups and commensal complexes
Alpheus armatus, Periclimenes yucatanicus, P.
rathbunae, and Mithraculus cinctimanus were con-
sistently found alone or in pairs on the same host
(Table 6). In contrast, groups of >2 conspecifics on
the same host occurred more often than expec ted by
chance for Thor amboinensis (up to 6 ind., χ23=
22.646, p < 0.001) and Ancylomenes pedersoni (up to
4 ind., χ21= 7.495, p = 0.006).
Up to 3 species of symbionts coex-
isted on 98 individuals of Bartho -
lomea annulata (16% of all B. annu-
lata that harbored crustaceans), 42
of Condylactis gigantea (31%), and
20 of Lebrunia danae (15%) (Fig. 7).
L. danae har bored 11 different com-
mensal com plexes, but none were
particular ly frequent. B. annulata har-
bored 8 different commensal com-
plexes, of which the most frequent
(86%) was constituted by Alpheus
armatus and Ancylomenes pedersoni,
the 2 symbionts with the highest
affinity for this host (Fig. 7a). Coexist-
ing individuals of Alpheus armatus
and Ancylomenes pedersoni were in -
variably in different places relative to
the host (under and on the host,
respectively, or under and near the
host). Six commensal complexes oc -
curred in C. gigantea, with the most
frequent (62%) also consisting of the
2 symbiontic species with the great -
est affinity for this host: Thor ambo -
inensis and Mithraculus cinctimanus
(Fig. 7b). However, in this case, the 2 symbionts were
often under the host at the same time.
Host anemones
The anemones Bartholomea annulata, Condylactis
gigantea, and Lebrunia danae occur on coral reefs
throughout the Caribbean region, but their relative
abundance varies widely with geographic area and
local habitat features (e.g. Panamá: Sebens 1976;
Colombia: Barrios-Suárez et al. 2002; Hispaniola:
Herrera-Moreno & Betancourt-Fernández 2002). In
the PMCR, B. annulata is the most abundant and C.
gigantea the least abundant of these 3 anemone spe-
cies, but the density distribution of each species by
reef zone remains rather stable over time, suggesting
that these sessile organisms quickly acclimate to
local microhabitats. However, reef zone differently
affects the density and size of B. annulata and C.
gigantea, and the density but not the size of L. danae.
These contrasting results may reflect interspecific
differences in susceptibility to local environmental
features (e.g. the flow regime, which may vary in
effects on feeding efficiency with anemone size),
Crustacean species Host anemone species
B. C. L. Total
annulata gigantea danae
Alpheus armatus 598 2 3 603
Thor amboinensis 15 167 59 241
Ancylomenes pedersoni 158 3 5 166
Mithraculus cinctimanus 48 84 29 161
Periclimenes yucatanicus 14 22 25 61
Periclimenes rathbunae 2 6 45 53
Subtotal 835 284 166 1285
Facultative associates
Stenorhynchus seticornis 26 19 0 45
Mithrax sp. 1 6 6 13
Mithraculus sculptus 1517
Stenopus hispidus 3205
Mithrax pilosus 2114
Mithraculus forceps 1203
Macrocoeloma trispinosum 2103
Brachycarpus biunguiculatus 2103
Cinetorhynchus rigens 1113
Subtotal 39 38 9 86
Total 874 322 175 1371
Table 4. Bartholomea annulata, Condylactis gigantea, and Lebrunia danae.
Crustacean species and numbers of individuals observed to associate with 3
sea anemone host species. Symbiotic species establish long-term associations
with hosts, while facultative associates are primarily free- living but may asso-
ciate with anemones for brief periods (Ross 1983, Gwaltney & Brooks 1994)
Effect df MS Fp
Intercept 1 357.702 161.030 <0.001
CS 5 21.887 9.853 <0.001
RZ 2 2.718 1.224 0.306
CS × RZ 10 2.704 1.217 0.313
Error 36 0.504
T 3 1.695 6.193 0.001
T × CS 15 0.537 1.960 0.025
T × RZ 6 0.418 1.527 0.176
T × CS × RZ 30 0.242 0.884 0.641
Error 108 0.274
Table 5. Repeated-measures ANOVA of crustacean sym-
biont density (ln[n + 1] 0.25 ha−1) with crustacean species
(CS; 6 levels corresponding to 6 species of crustacean sym-
bionts) and reef zone (RZ; back reef, reef channels, fore reef)
over time (T; spring, summer, autumn, winter)
Briones-Fourzán et al.: Caribbean anemones and symbiotic crustaceans
microhabitat requirements, reproductive strategy,
and photosynthetic efficiency of dinoflagellate endo -
symbionts borne by these cnidarians.
Because anemones depend on water flow to bring
them food, but risk being dislodged or broken by
drag forces (Koehl 1977), their dimensions in a given
flow habitat involve a trade-off between maximizing
food availability and minimizing flow forces and
physical stress (Anthony 1997). Although anemones
can reduce drag by retracting, and many are capable
of polyp shrinkage, maximum feeding efficiencies
are attained by small anemones at high flow regimes,
and by large anemones at slow flow regimes
(Anthony 1997, Titus 2011). In the PMCR, water
enters the reef lagoon via waves breaking on the
coral reef and exits the lagoon through large reef
channels. This circulation regime ensures good
flushing (average turnover time: 2.25 h; Coronado et
al. 2007), but results in high levels of water motion
Crustacean species Group size
Alpheus armatus 429 87 – – –
Thor amboinensis 80 27 15 6 4 3
Ancylomenes pedersoni 100 17 8 2
Mithraculus cinctimanus 149 6 – – –
Periclimenes yucatanicus 43 9 ––––
Periclimenes rathbunae 47 3 ––––
Table 6. Group sizes of conspecific crustacean symbionts
co-occurring on the same host anemone individuals
Fig. 6. Bartholomea annulata, Condylactis gigantea, and
Lebrunia danae. (a) Density (ind. 0.25 ha−1, mean ± SE) of
crustacean symbionts by reef zone, (b) percentages of indi-
viduals of each species distributed among 3 species of host
anemones, and (c) 3 positions on hosts. Similar letters in
columns for each species denote statistically similar groups.
Numbers in () on x-axes denote sample sizes. Aa: Alpheus
armatus; Ap: Ancylomenes pedersoni; Py: Periclimenes
yucatanicus; Pr: P. rathbunae; Ta: Thor amboinensis; Mc:
Mithraculus cinctimanus
Fig. 7. Bartholomea annulata, Condylactis gigantea, and Le-
brunia danae. Diversity and percent frequency of commen-
sal complexes in hosts harboring >1 symbiont species: (a)
B. annulata, (b) C. gigantea, and (c) L. danae. Abbreviations
for symbiotic crustacean species as in Fig. 6
Mar Ecol Prog Ser 470: 55–68, 2012
and sediment re-suspension in the shallow back reef
(Ruiz-Rentería et al. 1998), and in a high flow regime
through the reef channels (average current velocity:
20 cm s−1) compared to the fore reef (2 to 3 cm s−1;
Coronado et al. 2007), potentially explaining the gen-
erally smaller size of anemones on the back reef and
in reef channels relative to the fore reef.
The dinoflagellate genus Symbiodinium comprises
several types within 8 subgeneric clades or lineages
(A to H), and the types borne by a particular host spe-
cies may vary with geographical location (Venn et al.
2008). In the PMCR, a variety of cnidarian hosts
living at depths of 0 to 15 m, including Bartholomea
annu lata and Lebrunia danae, bear exclusively Sym-
biodinium type C1, suggesting that this type has a
relatively high degree of photosynthetic plasticity
(LaJeunesse 2002). However, B. annu lata strongly
tends to occupy crevices in sand pockets (e.g. Sebens
1976, Barrios-Suárez et al. 2002), a type of microhab-
itat that is more common in the back reef and reef
channels than in the fore reef (Ruiz-Rentería et al.
1998). Moreover, individuals of B. annulata spawn
twice a year but also under go pedal laceration, a type
of clonal replication that helps to maintain habitat
space and stable population sizes (Jennison 1981,
Titus 2011). In the laboratory, small B. annulata
(<28 cm2TCSA) replicate by pedal laceration more
often than larger conspecifics (Titus 2011), while in
the field, B. annulata replicate more frequently on
near-shore reefs ex posed to more suspended particu-
late matter than on offshore reefs with less sedimen-
tation and more light penetration (Nelsen 2008). In
conjunction, these features of B. annulata may under-
lie its greater density, but smaller mean size, in the
reef channels and back reef relative to the fore reef.
We found no information on the reproductive strat-
egy of L. danae, but a congeneric species, L. coralli-
gens, releases larvae that are negatively phototropic,
show aggregated settlement behavior, and settle
most frequently around the bases of the adults, with
settlement and metamorphosis occurring within 24 h
(Lewis 1984). If L. danae shows similar reproductive
and settlement strategies as L. coralligens, these fea-
tures might account for the similar size distribution
and mean size of L. danae in all 3 reef zones.
However, L. danae occupies crevices in hard sub-
strates and rarely occurs at depths <5 m (Herrn kind
et al. 1976, Sebens 1976, Herrera-Moreno & Betan-
court-Fernández 2002), explaining its greater densi-
ties in the fore reef and reef channels relative to the
back reef.
In the PMCR, Symbiodinium clade-A types are
more constrained to hosts living within 0 to 5 m depth
below the water surface, suggesting photo accli -
mation to high irradiance, and Condylactis gigantea
bears a mixture of types A4a, C1, and A3 (La Jeunesse
2002). This may explain the rather patchy distribution
of C. gigantea and its generally lower densities in reef
channels. On the other hand, because this species re-
produces only sexually with individuals spawning
once per year but over a prolonged reproductive pe-
riod (Jennison 1981), the multimodal size distribution
of C. gigantea in all 3 reef zones likely reflects differ-
ent pulses in larval recruitment.
Crustacean associates occurred in a far higher pro-
portion of individuals of Bartholomea annulata
(72.8%) and Condylactis gigantea (70.7%) than they
did in Lebrunia danae (27.2%). Stanton (1977) also
found crustaceans in only 26% of L. danae in his
study area in the Bahamas. Although both the proba-
bility of harboring at least 1 crustacean and the num-
ber of crustaceans per individual anemone increased
with size in all 3 host species, individuals of C. gigan-
tea harbored, on average, 1.6 and 4.5 times as many
crustaceans as did individuals of B. annulata and L.
danae, respectively. This result cannot be entirely
ascribed to the comparatively larger size of C. gigan-
tea, because the mean sizes of L. danae and B. annu-
lata were similar. However, as C. gigantea and B.
annulata bear most of their dinoflagellate endosym-
bionts within their feeding tentacles, these anemones
tend to remain continuously expanded so as to maxi-
mize light capture during the day and prey capture
during the night (Sebens & DeRiemer 1977), poten-
tially providing relatively stable habitats for their
crustacean associates. By contrast, L. danae, in addi-
tion to having larger nematocysts and producing
more potent toxic compounds than other sea ane -
mones (Herrnkind et al. 1976, Sánchez-Rodríguez &
Cruz-Vázquez 2006), contains most of its endosym-
bionts within auxiliary structures (‘pseudotentacles’)
that are incapable of feeding behavior. Thus, during
the day, the pseudotentacles are expanded and the
feeding tentacles contracted, while the opposite
occurs at night (Sebens & DeRiemer 1977, Stanton
1977). In conjunction, these features of L. danae may
provide a less stable or less suitable habitat for crus-
tacean associates.
Crustacean symbionts
The vast majority (93.8%) of the crustacean asso -
ciates of these anemones belonged to 6 species of
symbionts. Although the 6 symbiont species oc -
curred in all 3 host species, some exhibited a high
Briones-Fourzán et al.: Caribbean anemones and symbiotic crustaceans
degree of affinity for a host species. A variety of
commensal complexes were found in the 3 host
species, reflecting differences in intra- and inter-
specific behavioral interactions and microhabitat
requirements among symbionts (Herrnkind et al.
1976, Mercado & Capriles 1982, Wirtz 1997). Inter-
estingly, the highest diversity of commensal com-
plexes occurred in Lebrunia danae, the host with
the lowest proportion of individuals harboring crus-
taceans, and the lowest diversity occurred in
Condylactis gigantea, the host with the largest
mean size and a high proportion of individuals har-
boring crustaceans.
The most abundant symbiont by far was Alpheus
armatus. This alpheid shrimp is generally considered
an obligate symbiont of Bartholomea annulata
(Knowlton 1980, Knowlton & Keller 1983), although
field (Herrnkind et al. 1976) and laboratory studies
(Knowlton & Keller 1985) suggest that it may also use
other hosts, at least briefly. In our study, 99% of the
A. armatus (n = 603) associated with B. annulata, but
3 ind. associated with Lebrunia danae and 2 with
Condylactis gigantea. These shrimps live in the same
cavity as their host and are highly territorial, espe-
cially the juveniles, whereas the adults may share
their host only with a conspecific of the opposite sex
(Limbaugh et al. 1961, Knowlton 1980, Knowlton &
Keller 1983). Indeed, 90% of the A. armatus that we
observed were under the host, and 71% were
dwelling alone, and the rest in pairs. The high
degree of affinity of A. armatus for B. annulata, and
its tendency to dwell alone, resulted in a similar den-
sity distribution by reef zone of these 2 species.
Ancylomenes pedersoni also exhibited a high
de gree of affinity for Bartholomea annulata, yet
these 2 species differed in their density distribution
by reef zone. This result reflects the tendency of
Ancylomenes pedersoni to form groups and its
ability to acclimate to different hosts in the ab -
sence of B. annulata (e.g. Silbiger & Childress
2008, Mascaró et al. 2012), as well as the lower
probability of finding crustacean associates in B.
annulata in the reef channels (where this anemone
exhibited the highest densities). The high fre-
quency of coexistence of Ancylo menes pedersoni
and Alpheus armatus in B. annulata appears
related to the inverse pattern of host space use ex -
hibited by these 2 symbionts. Periclimenes rath-
bunae exhibited a strong affinity for Lebrunia
danae, and because these shrimps occurred alone
or in pairs in the same host, the density distribution
by reef zone was similar for these 2 species. In
other locations, P. rathbunae is strongly associated
with the sun anemone Stichodactyla helianthus
(Hayes & Trimm 2008, Silbiger & Childress 2008),
a species that was absent from our study sites
because, in the PMCR, it occurs only on the reef
crest at depths of 0.5 to 1.5 m (González-Muñoz
2009). P. yucatanicus occurred in similar percent-
ages on Condylactis gigantea and L. danae, and to
a lesser extent on B. annulata. In Florida, P.
yucatanicus was strongly associated with C. gigan-
tea and only occurred on B. annulata when C.
gigantea was scarce (Silbiger & Childress 2008).
Ancylomenes pedersoni and Periclimenes yucatan-
icus both potentially serve as cleaner shrimps (Lim-
baugh et al. 1961, Bunkley-Williams & Williams
1998), although the former performs this activity
more effectively than the latter (McCammon et al.
2010). It has been suggested that anemones harbor-
ing multiple A. pedersoni might be more easily iden-
tified as ‘cleaning stations’ by reef fishes, and that
this might explain the tendency of A. pedersoni to
occur in groups on the same host (Limbaugh et al.
1961, Herrnkind et al. 1976, Huebner & Chadwick
2012a). However, Huebner & Chadwick (2012b)
found that the size of the anemone Bartholomea
annulata rather than the number of associated A.
pedersoni acts as a primary attractant to client fishes.
Also, social interactions may influence group size
and the distribution of conspecific cleaner shrimps
among hosts (Limbaugh et al. 1961, Mahnken 1972,
Wicksten 1995). This may also occur in P. rathbunae,
a non-cleaner shrimp, which has been found alone or
in pairs on the same host in some locations (e.g.
Mahnken 1972, the present study), and in groups of
up to 11 ind. on the same host in other locations (e.g.
Mercado & Capriles 1982, Hayes & Trimm 2008).
Although heterospecific palaemonids can coexist
on the same host (Mahnken 1972, Stanton 1977,
Williams & Bunkley-Williams 2000), we observed
coexistence of Ancylomenes pedersoni and Pericli -
menes yucatanicus on only 2 Bartholomea annulata
and 1 Lebrunia danae, and coexistence of P. rath-
bunae and P. yucatanicus on only 2 L. danae. In all
cases, heterospecific shrimps were on different parts
of the host, suggesting some degree of interspecific
competition for microhabitat, in particular between
A. pedersoni and P. yucatanicus, given their similar
pattern of host space use. We did not observe coexis-
tence of A. pedersoni and P. rathbunae, but this was
possibly due to the high affinity for different hosts
exhibited by these 2 palaemonids.
Thor amboinensis was the second most abundant
symbiont in our study sites, and these small hippo -
lytid shrimps associated mostly with Condylactis
Mar Ecol Prog Ser 470: 55–68, 2012
gigantea (70% of all shrimps on this host), with up to
6 individuals co-occurring in a single host. In gen-
eral, T. amboinensis occurs in groups more often than
expected by chance alone (Wirtz 1997, Baeza &
Piantoni 2010, the present study), potentially reflect-
ing the small size and limited defensive capability of
these shrimps, which may preclude solitary individu-
als from monopolizing the host (Thiel & Baeza 2001).
T. amboinensis occurred in many different commen-
sal complexes on all 3 host species, and coexisted,
often side by side, with each of the other 5 symbionts,
as observed also in Puerto Rico (Mercado & Capriles
Over 50% of the small commensal crabs Mithra -
culus cinctimanus associated with Condylactis gi -
gan tea, and the rest with either of the other 2 hosts.
Patton (1979) remarked that these majid crabs are
usually solitary on hosts, and only occasionally occur
in pairs, as we found in the present study. Most crabs
were located under the host, a similar pattern as that
of M. commensalis crabs associated with Lebrunia
danae in the Bahamas (Herrnkind et al. 1976). How-
ever, according to Patton (1979), M. commensalis
(first described by Manning 1970) is actually the
juvenile phase of M. cinctimanus, and according to
Wagner (1990), only the juveniles are symbiotic with
anemones, whereas the adults are free-living. In our
study, M. cinctimanus coexisted with all other sym-
bionts except Alpheus armatus, possibly because
these 2 symbionts exhibited a very similar pattern of
host space use, and the highly territorial and aggres-
sive alpheid can easily displace the smaller crab from
a host (Knowlton 1980).
In summary, we found substantial variability in
several ecological features of 3 species of host ane -
mones and 6 species of their crustacean symbionts in
the PMCR. These findings are relevant, because
even though the PMCR was declared a national park
in 1998, effectively protecting these animals from
being extracted for the aquarium trade (Instituto
Nacional de Ecología 2000), it is very close to a shore
with one of the highest rates of touristic and urban
development in Mexico (Rodríguez-Martínez 2008).
Time-series ecological data from local sea grass and
reef communities have detected gradual changes
over time that may reflect an increase in pollution
caused by the rapid rise in urban and tourist develop-
ment along the coast and inland from Puerto More-
los, coupled with poor water-management practices
(Rodríguez-Martínez et al. 2010, van Tussenbroek
2011). Coastal development also tends to increase
water turbidity, especially in shallow reef lagoons
and back-reef areas (Fourqurean & Robblee 1999,
Sullivan-Sealy 2004), potentially altering the distrib-
ution and abundance of anemones by affecting their
mean size and rate of clonal replication, and photo-
synthetic efficiency of their endosymbionts (Sullivan-
Sealy 2004, Nelsen 2008). This might further impact
their crustacean symbionts, in particular those that
exhibit a high affinity for a given host species (e.g.
Alpheus armatus), and those that serve as cleaning
shrimps, which depend on large hosts to attract fish
clients, with potential cascading effects on the coral
reef system (Mahnken 1972, Huebner & Chadwick
2012b). Therefore, the present study provides base-
line information to further assess the potential influ-
ences of local (e.g. coastal development and pollu-
tion) and global (e.g. climate change) anthropogenic
stressors on anemone−crustacean symbioses.
Acknowledgements. We thank Erika Magallón-Gayón for
helping with the fieldwork and Universidad Nacional
Autónoma de México for funding. The Consejo Nacional de
Ciencia y Tecnología (México) provided an MSc studentship
to M.P.O. Annual permits to conduct fieldwork within the
National Park ‘Arrecifes de Puerto Morelos’ were issued by
Comisión Nacional de Acuacultura y Pesca and validated by
Comisión Nacional de Áreas Naturales Protegidas.
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Editorial responsibility: Peter Edmunds,
Northridge, California, USA
Submitted: July 2, 2012; Accepted: August 29, 2012
Proofs received from author(s): November 27, 2012
... On Caribbean coral reefs, Pederson's cleaner shrimp Ancylomenes pedersoni (Chace) is the most common and ecologically important cleaner shrimp (Limbaugh et al., 1961;Briones-Fourzán et al., 2012;Huebner et al., 2019). Ancylomenes pedersoni are dedicated cleaners, defined as a species committed to a cleaning lifestyle for all or some of their nonlarval ontogeny (Vaughan et al., 2017). ...
... Ancylomenes pedersoni are dedicated cleaners, defined as a species committed to a cleaning lifestyle for all or some of their nonlarval ontogeny (Vaughan et al., 2017). Almost always inhabiting sea anemones (Limbaugh et al., 1961), its primary host is the corkscrew sea anemone, Bartholomea annulata (LeSueur) (Mahnken, 1972;Briones-Fourzán et al., 2012;Mascaró et al., 2012;Huebner & Chadwick, 2012a, 2012bTitus et al., 2017a) with which they can be found living singly or in groups of up to 12 individuals (Titus et al., 2015b). The most abundant anemone in the Caribbean, B. annulata is a habitat generalist found solitarily or in small aggregations on coral reefs, seagrass beds, and hard-bottom habitats (Briones-Fourzán et al., 2012;Titus et al., 2017b;O'Reilly et al., 2018). ...
... Almost always inhabiting sea anemones (Limbaugh et al., 1961), its primary host is the corkscrew sea anemone, Bartholomea annulata (LeSueur) (Mahnken, 1972;Briones-Fourzán et al., 2012;Mascaró et al., 2012;Huebner & Chadwick, 2012a, 2012bTitus et al., 2017a) with which they can be found living singly or in groups of up to 12 individuals (Titus et al., 2015b). The most abundant anemone in the Caribbean, B. annulata is a habitat generalist found solitarily or in small aggregations on coral reefs, seagrass beds, and hard-bottom habitats (Briones-Fourzán et al., 2012;Titus et al., 2017b;O'Reilly et al., 2018). This anemone species also serves as a visual cue for reef fish to locate A. pedersoni cleaning stations (Huebner & Chadwick, 2012b). ...
Cleaning mutualisms are important interactions on coral reefs. Intraspecific variation in cleaning rate and behaviour occurs geographically and is often attributed to local processes. However, our understanding of fine-scale variation is limited, but would allow us to control for geography and region-specific behavioural patterns. Here, we compare the cleaning activity of Pederson's cleaner shrimp ( Ancylomenes pedersoni ) on two neighbouring, yet ecologically dissimilar, reef systems in Honduras: Banco Capiro, an offshore bank close to significant land runoff with high coral cover but a depleted fish population, and an oligotrophic fringing reef around the island of Utila, with lower coral cover but high fish abundance and diversity. The proportion of realized to potential fish clientele was <60% at both sites, and the composition of clientele was neither reflective of the demographics of the resident assemblages at each site nor similar between sites. Parrotfishes represented 13–15% of total fish abundance at both sites yet accounted for >50% (Banco Capiro) and 10% (Utila) of all cleans. Conversely, the schoolmaster snapper ( Lutjanus apodus ) represented ~1% of total fish abundance at both sites yet accounted for 40% (Utila) and 1% (Banco Capiro) of all cleans. After standardizing our cleaning rate data by clientele abundance, we find that clientele at Banco Capiro engage in over four times as many cleaning encounters per hour with A. pedersoni than at Utila. Our study highlights the variable nature of coral reef cleaning interactions and the need to better understand the ecological and environmental drivers of this biogeographic variation.
... Sea anemones (class Anthozoa; order Actiniaria) exhibit a widespread distribution from tropical to polar seas and from the shoreline to the abyss (Shick, 2012), with a majority of species living attached to hard substrates, although some burrow into sand or mud (Kristensen et al., 1991;Mangum, 1970). Consistent with their ubiquitous occurrence in marine benthic communities, sea anemones play important and diverse roles in benthic food webs (Briones-Fourzán et al., 2012;Ross, 1967;Sebens, 1976). ...
Sea anemones are often presented as a major component of benthic communities and described as ecologically important in benthic food webs. However, studies on the trophic ecology of deep-sea species are rare. Here, the feeding habits and dietary sources of three species of bathyal sea anemones (Actinostola callosa, Actinauge cristata, Urticina sp.) from the Northwest Atlantic were studied in a multi-faceted approach including stable isotopes, gastrovascular contents, lipid and fatty acids analysis and observations in a mesocosm. Stable isotope analysis showed that A. callosa sits at a slightly lower trophic level than A. cristata and Urticina sp. and that the two latter species rely on different carbon sources at roughly the same trophic level. The gastrovascular cavity contents and mesocosm study revealed that all three species ingest a variety of food items, from inorganic materials to a diversity of metazoans, including whole large prey. Total lipid content varied across species and was highest in Urticina sp. Phospholipids constituted the main lipid class in all three species, with consistently high levels of wax ester storage lipids. All sea anemones were also characterized by high proportions of mono and polyunsaturated fatty acids (MUFA and PUFA) as well as ω3 and ω9 FAs, and strikingly low proportions of 20:4ω6 (ARA). High values of 20:5ω3 (EPA), 20:1ω9 and 22:1ω11(13) evoke a diet centered on zooplankton, with notable particularities. For instance, Urticina sp. had the highest PUFA to saturated FAs ratio, indicative of carnivory. Overall, results suggest that the three sea anemone species occupy different niches in the spectrum of opportunistic polyphagous predation/feeding, with Urticina sp. relying chiefly on more energetic and larger prey and A. cristata targeting smaller zooplankton, foraminifera and particulate food, highlighting that large actinians play diverse roles in benthic food webs.
... The field data analysed herein showed variations in the abundance of both anemones and snapping shrimps amongst the seven regions in the Mexican Caribbean (Table 1), indicating a varying availability of optimal and suboptimal microhabitats for B. annulata throughout the study area. Previous studies on the distribution of B. annulata in the Caribbean have explained variations in the abundance within geographic areas in terms of the, exposure to wave dynamics, microhabitat accessibility, photosynthetic efficiency and food availability (Cornell and Lawton, 1992;Amarasekare, 2002;Begon et al., 2009;Briones-Fourzán et al., 2012;Chesson, 2020). ...
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Bartholomea annulata is a facultative host of the A. armatus species complex. In the Mexican Caribbean it is commonly found in cracks and crevices located where the vertical walls meet the sandy bottom or on large coral patches away from the sand. To protect themselves from predators, anemones often contract their hydraulic body into a cavernous den and extend the stinging tentacles toward the entrance. The high sediment dynamics of the region, however, result in a permanent risk of animal shelters to be obstructed by sand. By both analysing field data and conducting laboratory experiments with artificial shelters, the present study explored the den cleaning behaviour widely extended amongst alpheid shrimp, and its role in the alpheid-anemone symbiotic interaction. Videorecordings showed that den cleaning was composed of three main behaviours: digging, tossing and tamping. It commenced as soon as 7.2 ± 10.5 min after anemones were recognised by alpheids, and behaviours were displayed systematically amongst all 12 replicates. Despite being completely burrowed in sand, Alpheus spp. were capable of finding the anemone and liberating the entrance of the artificial shelters in less than 2.5 h. In addition, manipulative experiments showed that anemones confronted with shelters that were obstructed with sediment had a 25% probability of fully retracting when Alpheus spp. were absent, compared to a 75% probability when shrimps had cleaned the shelter’s entry and internal passage. The analysis of field data indicated that the presence of alpheid shrimps as symbionts of B. annulata was 30% higher amongst anemones in close contact with sandy bottoms than when inhabiting crevices on the top or lateral walls of hard substrates, away from the sediment. Overall, our study concludes that den cleaning constitutes a quick and effective mechanism to assure the anemone’s full retraction into their den, and by keeping the sediment away, alpheids provide the necessary conditions that serve both the anemone’s and the shrimp’s higher chances of acquiring maximum protection from predators. This advantageous exchange in protection partially explains why alpheids are more frequently present in B. annulata in interface microhabitats where the benefit of the interaction is maximised.
... Coral reefs are among the world's most productive and biologically diverse ecosystems (Odum & Odum, 1955;Reaka-Kudla, 1997), performing many important ecological roles and supporting a variety of fish, invertebrate, and algal species (Briones-Fourzán et al., 2012). Shallow warm-water coral reefs cover less than 0.1% of the seabed but support approximately 1-9 million inhabitant species (Fisher et al., 2015;Reaka-Kudla, 1997). ...
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Coral reefs are amongst the world’s most productive and biologically diverse ecosystems and in recent decades have experienced an unparalleled decline due to various anthropogenically induced stressors. Ultraviolet (UV) filters found within personal care products such as sunscreen are an emerging chemical pollutant with a growing concern of toxicity to reef organisms. In this study a systematic literature review was conducted to [1] determine the current understanding of spatial distribution and occurrence of UV‐filters exposed to the marine environment, [2] synthesise current ecotoxicological thresholds of relevant reef organisms under various UV filter exposures, [3] identify research gaps related to both exposure and toxicity of UV‐filters in coral reef ecosystems. With gaps identified, a survey was developed and distributed to experts in the field representing academic, governmental, not‐for‐profit, and industry researchers in order to prioritise research gaps and inform future research efforts. The survey identified the need for better understanding of the impacts of co‐stressors, long‐term exposure, mixture and degradation product exposure and realistic environmental conditions. Ultimately, this review, will help guide priority research efforts to understand the risks of UV‐filter exposure to coral reef ecosystems. This article is protected by copyright. All rights reserved.
... Sea anemones are hosts for many symbionts. Their symbiosis with anemonefishes is well known and has been much studied (e.g., Fautin, 1991), while there also is an extensive literature about the associations between sea anemones and various decapod crustaceans, especially hermit crabs (cf, Ross, 1983), spider crabs (Wirtz & Diesel, 1983;Calado et al., 2002;Briones-Fourzán et al., 2012;Landmann et al., 2016), porcelain crabs (e.g., Valdivia & Stotz, 2006), and shrimps (e.g., Wirtz, 1997). Mysids (e.g., Wittmann, 2008Wittmann, , 2013 and copepods (e.g., Bouligand, 1966;Vader, 1970c;Gotto, 1979Gotto, , 1993Humes, 1982;Lønning & Vader, 1984) also regularly occur as symbionts of sea anemones. ...
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We present an updated survey of the Amphipoda that live in association with sea anemones. These amphipods can be divided into four groups: 1) symbiotic amphipods using sea anemones mainly for protection, but feeding largely independently; 2) amphipods feeding on sea anemones, but not permanently associated; 3) symbiotic amphipods living permanently among the tentacles of the sea anemones; and 4) symbiotic amphipods living permanently in the gastrovascular cavity of the sea anemones. Contrary to previous speculations, it appears that the amphipods in groups 3 and 4 mainly feed on host tissue, and the anemone-eating amphipods can therefore generally be classified as micropredators (group 2), ectoparasites (group 3), and almost endoparasites (especially those species in group 4 that spend their entire life cycle inside their hosts). Although the associates in the latter two groups show various minor morphological, reproductive, and physiological adaptations to the symbiosis, these associations evolved many times independently. We provide new information on feeding ecology and a discussion of the evolution of these associations.
... (Although we here refer to these interactions as commensalisms, they are more accurately putative commensalisms; as we stress throughout this review, in many cases no quantification of plus/zero effects has been attempted). The largest subset of these studies (27%) described features of a commensalism, such as the community composition of commensal bacteria in different populations of birds (Grange et al. 2015), patterns of association between crustaceans and sea anemones based on season and anemone size (Briones-Fourzán et al. 2012), and human-mediated dispersal of domesticated cats (Koch et al. 2015). Biotic and/or abiotic factors affecting and/or affected by an interaction named as a commensalism made up 18% of these articles. ...
Commensalisms, interactions between two species in which one species benefits and the other experiences no net effect, are frequently mentioned in the ecological literature but are surprisingly little studied. Here we review and synthesize our limited understanding of commensalism. We then argue that commensalism is not a single type of interaction; rather, it is a suite of phenomena associated with distinct ecological processes and evolutionary consequences. For each form of commensalism we define, we present evidence for how, where, and why it occurs, including when it is evolutionarily persistent and when it is an occasional outcome of interactions that are usually mutualistic or antagonistic. We argue that commensalism should be of great interest in the study of species interactions due to its location at the center of the continuum between positive and negative outcomes. Finally, we offer a roadmap for future research. Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 51 is November 2, 2020. Please see for revised estimates.
... The species composition and temporal variations in abundance of the decapod fauna associated with seagrasses have been more studied in temperate and subtropical ecosystems (e.g., [9,14,15,20,21]) than in tropical ecosystems, such as Caribbean meadows dominated by Thalassia testudinum [8,13,19,[22][23][24][25]. In particular, ecological studies on the seagrass decapod fauna are very limited in the Mexican Caribbean coast, where previous studies have generally consisted of species lists with a few ecological observations (e.g., [26][27][28][29]), or have focused on one species [30] or a limited group of species [31]. ...
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The community composition of decapods associated with subtidal tropical seagrass meadows was analyzed in a pristine reef lagoon on the Mexican Caribbean coast in the summer of 1995 and winter of 1998. The macrophyte community was dominated by Thalassia testudinum followed by Syringodium filiforme, with interspersed rhyzophytic macroalgae and large patches of drift algae. In each season, 10 one-min trawls were made with an epibenthic sled (mesh aperture 1 mm) during the day and 10 during the night on each of five sites. In all, 53,211 decapods belonging to 119 species were collected. The most diverse taxa were Brachyura and Caridea, but the most abundant were Caridea and Anomura. Dominance was high, with three species (Latreutes fucorum, Cuapetes americanus, and Thor manningi) accounting for almost 50% of individuals, and 10 species accounting for nearly 90% of individuals. There was great similarity in community composition and ecological indices between seasons, but significantly more individuals and species in night versus day samples. In the 20+ years elapsed since the samples were taken, the reef lagoon has undergone substantial environmental changes due to extensive coastal development and, more recently, the decay of massive beachings of floating Sargassum macroalgae. This study constitutes a valuable baseline for future studies investigating the potential impact of these stressors on tropical seagrass-associated communities.
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Decapods are one of the most diverse crustacean orders, with around 17,500 extant species [...]
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Toxin production in nematocysts by Cnidaria phylum represents an important source of bioactive compounds. Using electrophysiology and, heterologous expression of mammalian ion channels in the Xenopus oocyte membrane, we identified two main effects produced by the sea anemone Bartholomea annulata venom. Nematocysts isolation and controlled discharge of their content, revealed that venom had potent effects on both voltage-dependent Na+ (Nav) channels and GABA type A channel receptors (GABAAR), two essential proteins in central nervous system signaling. Unlike many others sea anemone toxins, which slow the inactivation rate of Nav channels, B. annulata venom potently inhibited the neuronal action potential and the Na+ currents generated by distinct Nav channels opening, including human TTX-sensitive (hNav1.6) and TTX-insensitive Nav channels (hNav1.5). A second effect of B. annulata venom was an agonistic action on GABAAR that activated distinct receptors conformed by either α1β2γ2, α3β2γ1 or, ρ1 homomeric receptors. Since GABA was detected in venom samples by ELISA assay at low nanomolar range, it was excluded that GABA from nematocysts directly activated the GABAARs. This revealed that substances in B. annulata nematocysts generated at least two potent and novel effects on mammalian ion channels that are crucial for nervous system signaling.
The sexual system of the symbiotic shrimp Thor amboinensis is described, along with observations on sex ratio and host-use pattern of different populations. We used a comprehensive approach to elucidate the previously unknown sexual system of this shrimp. Dissections, scanning electron microscopy, size-frequency distribution analysis, and laboratory observations demonstrated that T. amboinensis is a protandric hermaphrodite: shrimp first mature as males and change into females later in life. Thor amboinensis inhabited the large and structurally heterogeneous sea anemone Stichodactyla helianthus in large groups (up to 11 individuals) more frequently than expected by chance alone. Groups exhibited no particularly complex social structure and showed male-biased sex ratios more frequently than expected by chance alone. The adult sex ratio was male-biased in the four separate populations studied, one of them being thousands of kilometers apart from the others. This study supports predictions central to theories of resource monopolization and sex allocation. Dissections demonstrated that unusually large males were parasitized by an undescribed species of isopod (family Entoniscidae). Infestation rates were similarly low in both sexes (≈11%–12%). The available information suggests that T. amboinensis uses pure search promiscuity as a mating system. This hypothesis needs to be formally tested with mating behavior observations and field measurements on the movement pattern of both sexes of the species. Further detailed studies on the lifestyle and sexual system of all the species within this genus and the development of a molecular phylogeny are necessary to elucidate the evolutionary history of gender expression in the genus Thor.
Despite the predominance of scleractinian corals as the constructors and the matrix of coral reefs, there exists a high diversity of other organisms on the substratum provided by these corals. The reef structure is dynamic and areas of cleared substratum are continuously supplied by the forces of physical collapse, bioerosion, and predation; yet sufficient evidence exists (Loya 1972, Porter 1972c, Connell 1973, Grigg and Maragos 1974) to illustrate the importance of space as a limiting resource on coral reefs.
The Mexican Atlantic coast extends from the westem Caribbean to the Gulf of Mexico. This is a subtropical environment where shallow seas are strongly influenced by the tourism-associated coastal development in generating multiple conflictive uses, as well as threatening the well being of the reefs themselves. Well-developed coral reefs are found along the Mexican Atlantic margin from the western Caribbean to the Gulf of Mexico. This chapter characterizes the wide array of coral reefs found in this area and the coral communities that colonize them. Differences in oceanic connectivity and terrestrial influence result in the delineation of three major reef subregions-Caribbean, Campeche Bank and southwest Gulf of Mexico reef systems. The environmental settings of these reefs, as well as the climatic and biological perturbations to which they have been subjected, are also discusses in the chapter. It reviews anthropogenic influences from fisheries to coastal development, and makes a gross assessment of the coral community condition in these reefs. The chapter also describes the coral reef protection in Mexico up to 2001, and comments on its problems and effectiveness.