Epibiontic communities on the freshwater shrimp Caridina ensifera (Crustacea, Decapoda, Atyidae) from Lake Poso (Sulawesi, Indonesia)

The epibiont communities of the freshwater shrimp Caridina ensifera, endemic to Lake Poso (Sulawesi, Indonesia), were analysed for the first time based on their morphological and biometrical characteristics and taxonomic position. Seven ciliated protozoans and a rotifer were examined: three suctorian ciliate protozoan species (Acineta sulawesiensis, Podophrya maupasi, and Spelaeophrya polypoides), three peritrichs (Zoothamnium intermedium, Vorticella globosa, and Cothurnia compressa), a haptorid (Amphileptus fusidens), and the rotifer species Embata laticeps. A mean number of 314.6 epibionts was found per shrimp specimen. The distribution of the epibiont species on the surface of the basibiont was recorded, to allow calculation of the density on the different colonized individuals of C. ensifera and on each anatomical unit of the shrimp. The most abundant species, Zoothamnium intermedium and Acineta sulawesiensis, were also the ones most widely distributed. The statistical analysis showed that Zoothamnium, Acineta, Podophrya, and Embata were the epibiont genera most widely distributed on the basibiont, and the pairs of epibiont genera Zoothamnium–Embata, Podophrya–Acineta, Spelaeophrya–Amphileptus, and Cothurnia–Vorticella followed a similar pattern of distribution. There was a significant difference between the distribution patterns of the different epibiont species on the shrimp. The analysis of the densities of the epibionts throughout the longitudinal axis of the shrimp showed a gradient from the anterior to the posterior end of the body, and a significantly different distribution of each epibiont species. Their colonization follows a certain pattern of behaviour, the species occupying the available substratum, with particular requirements of each functional group, but with a trend resulting in equilibrium among species and groups, compensating for diversity and density. The possible adaptations of the epibionts, as well as the colonization patterns are discussed.


Introduction
In recent years, a number of reports were dedicated to epibiosis in Crustacea (Dawson 1957;Eldred 1962;Maldonado and Uriz 1992;Gili et al. 1993;Morado and Small 1995;Dick et al. 1998;Key et al. 1999;Fernandez-Leborans andTato-Porto 2000a, 2000b). Poso, Central Sulawesi, Indonesia, in March 2004 (Figure 1). Samples were fixed in 95% ethanol and then transferred to 75% ethanol for light microscopy. In the laboratory, shrimps were dissected and each anatomical unit was observed under a stereoscopic microscope. Forty colonized specimens of C. ensifera were analysed, of which nine were ovigerous females.
For scanning electron microscopy (SEM) of the epibionts, shrimp specimens fixed in 95% ethanol were dehydrated in 100% ethanol for 30 min. Afterwards, they were criticalpoint dried with a BAL-TEC CPD 030, mounted on aluminium specimen stubs with standard adhesive pads and coated with gold-palladium using a Polaron SC7 640 Sputter Coater. Pictures were taken on a LEO 1450VP Scanning Electron Microscope (software: 32 V02.03) at 10 kV (see Fernandez-Leborans et al. 2006a).
Epibionts on the surface of the shrimp anatomical units were observed and counted under stereoscopic and light microscopes. Numbers of colonial species were indicated as number of zooids. In order to identify the protozoan epibionts, they were isolated and treated with the silver carbonate technique described by Fernandez-Leborans and Castro de Zaldumbide (1986), and also with methyl green and neutral red. Permanent slides were obtained from the stained ciliates. In order to identify the rotifers, the trophi were analysed using the procedure indicated by R. J. Shiel (University of Adelaide, Australia; personal communication), treating isolated specimens, placed in 10% glycerol/water solution with 2.5% sodium hypochlorite. Measurements of the epibionts were calculated using an ocular micrometer. Light microscope images were obtained using Image Analysis (KS300 Zeiss) and the diverse morphological features from the images were used to determine the epibiont species schemes. Statistical analyses were performed using the Statgraphics and SPSS programs. The tests used were the following: (1) multiple comparison analysis (for differences between distribution of epibiont species, and differences in colonization of right and left anatomical units); (2) principal component analysis (for groups of epibiont species with similar distribution); (3) hierarchical conglomerate analysis (to obtain clusters of anatomical units with similar colonization); (4) variance components (evaluation of Figure 1. Geographical area of the study. epibiont species versus variation in length and width of basibionts). Epibiosis along the anterioposterior axis of the basibiont was statistically treated in order to analyse the influence of the longitudinal activity gradient on colonization.

Epibionts of the genus Acineta
The ciliates were triangular in outline or bell-shaped, loricated, and pedunculate. The lorica completely surrounded the cellular body (28.8-78.7 mm long, 26.8-61.4 mm wide). The lorica had a free anterior part over the body enveloping the tentacles (13.2-15.5 mm long). The body (19.2-61.4 mm long, 19.2-49.9 mm wide) had two anterior lobular actinophores protruding on the corners, each with 13-31 capitate tentacles. The central area in the apical surface of the body was depressed. The macronucleus was rounded in shape and centrally located (7.6-15.3 mm long, 7.6-17.3 mm wide). There was a spherical micronucleus located near the macronucleus. The stalk (19.2-26.9 mm long, 5.8-9.6 mm wide) joined the lorica via a cup-like expansion (Table I; Figures 2a,3,4).
These ciliates belong to the genus Acineta (Lynn and Small 2000). The most distinctive feature of these ciliates was the lorica prolonged anteriorly around the tentacles. The ciliates belong to the species Acineta sulawesiensis Fernandez-Leborans et al., 2006. In comparison to ciliates of this species that have been observed previously in the other three lakes of the Malili system, they have a longer stalk, and a lower number of tentacles per actinophore.

Epibionts of the genus Podophrya
The individuals had a characteristic spheroid body (7.6-53.7 mm long, 7.6-32.6 mm wide). In comparison to the body, the stalk can reach a considerable length (15-192 mm long). The cellular body had an external layer. The capitate tentacles (10-15) were spread over the entire surface of the body. The rounded macronucleus (3.8-15.4 mm long) was located excentrically. An oval micronucleus was placed near the macronucleus (Table II; Figures 2b,5).
The suctorians belong to the genus Podophrya (Curds 1986;Lynn and Small 2002). The species most similar to these ciliates was Podophrya maupasi Butschli, 1889; they have in common their dimensions, their freshwater habitat, the spherical form of the cellular body, the absence of lorica, tentacles slightly trumpet-shaped at their end, a spherical macronucleus centrally positioned and a thick external layer to the zooid. In the description of Curds (1986) the ciliates were free-living and attached to aquatic vegetation and inanimate objects, whereas in our study they were epibionts and attached to freshwater crustaceans.

Epibionts of the genus Spelaeophrya
The ciliates were bell-or trumpet-shaped, with the body flattened and covered by a thick pellicle. The body length fluctuated between 48 and 157.4 mm (13.4-28.8 mm wide). The body joined the substrate without a developed stalk, which was sometimes replaced by a basal funnel-shaped area, as a lorica, with a length of 25.7-37.3 mm (maximum width, 19.2-25.7 mm), which in several specimens joined the rest of the body via a constriction. In some specimens this posterior zone of the body seemed to articulate with the anterior area of the body, forming an angle, as Nie and Lu (1945) have indicated. The posterior end of the body was expanded in a circular disc for attachment to the surface of the basibiont. This basal disc was 14.9-32.2 mm in diameter. In the apical area, there were 12-20 tentacles located over this surface; no actinophores were present. Each tentacle was 18-30.9 mm in length. The macronucleus was elongated and arranged alongside the longitudinal axis of the ciliate (24.9-53.7 mm long, 3.8-11.5 mm wide). In several individuals, the macronucleus was considerably flattened, and its anterior part can appear widened. The macronucleus had an anterior section forming a right angle with the rest of the macronucleus in several specimens. There were four to six spherical micronuclei near the macronucleus. In the middle of the body there were one to three contractile vacuoles, the pores of which can be distinguished in the surface of the ciliate. The SEM images did not show the division of the body with a posterior loricated area. The surface of the ciliate was continuous from the apical surface to the basal disk (Table III;   These ciliates belong to the genus Spelaeophrya (Lynn and Small 2002). The trophonts had a trumpet-shaped body with tentacles distributed over the distal end. There are two species of Spelaeophrya: S. polypoides Daday, 1910 andS. troglocaridis Stammer, 1935. According to Matthes et al. (1988) these two species differ in the body shape (divided into a basal hyaline part and another anterior part in S. polypoides, apically funnel-shaped in S. troglocaridis (edge of the funnel with a seam) and the macronucleus (elongated or wound, apically often bent in S. polypoides, band-like, apically thickens in S. troglocaridis). The basal zone of the body has been considered as a lorica (Nie and Lu 1945), or as a hyaline zone (Matthes et al. 1988). There are no significant differences with respect to the body size, number of tentacles, or number of micronuclei between the two species. In our specimens, there were individuals with both types of macronucleus, and the presence of a posterior pseudoloricate area seems to be a mechanism that allows the ciliate to bend and which joins the body with the basibiont surface. The external observation of the pellicle did not show any division of the ciliate body when observed by SEM (Figures 6, 7). In summary, both species could be included in the first described, Spelaeophrya polypoides Daday, 1910, to which the ciliates observed belong.

Epibionts of the genus Zoothamnium
The peritrich ciliates were colonial, with 2-18 zooids linked by a ramified stalk, which contained a contractile myoneme. The body of the zooid was oval, elongated (28.8-76.8 mm long, 23-38.4 mm wide). The macronucleus was C-shaped (3.8-30.7 mm long, 3.8-23 mm wide). The micronucleus was spherical and disposed next to the macronucleus. The peristomal disc was short, approximately half of the maximum body width. The stalk was broad (3.8-28.8 mm wide). This stalk was very diaphanous with a rounded contour. The contractile myoneme (spasmoneme) was located inside the stalk. The width of the stalk increased towards the base of the colony, where it was attached to the basibiont. The stalk joined to the cellular body of the zooid by a cup-shaped structure (suprastylar area), with a longitudinal striation (Table IV; Figures 2d,14,15).
These epibionts belong to the genus Zoothamnium (Lynn and Small 2000). The ciliates were similar to those of Zoothamnium intermedium Precht, 1935. They coincided with the description of Z. intermedium in: the dichotomously branching colonies (although the number of individuals per colony was lower in the ciliates studied than in the description); the zooid dimensions; and the C-shaped macronucleus (Valbonesi and Guglielmo 1988).

Epibionts of the genus Vorticella
The ciliates were solitary and stalked. The body was globulous, and more or less ovoid when contracted (23-46 mm long, 17.3-34.6 mm wide). The macronucleus was C-shaped (13.4-21.1 mm long, 5.8-17.3 mm wide) and laid transversely across the center of the zooid widening at its extremes. A spherical micronucleus was placed next to the macronucleus.
On the anterior part of the body, the peristomial lip was narrow and shorter than the width of the body. The peristomial disc was convex and elevated on the peristome. The stalk was elongated (13.4-153.6 mm long, 5.8-19.2 mm wide), contained a contractile myoneme along its entire length and had between two and five bends (Table V; Figures 2e, 16). These ciliates belong to the genus Vorticella (Warren 1986;Lynn and Small 2000). The species most similar to these ciliates was Vorticella globosa Ghosh, 1922. They have in common the size and shape of the body; the C-shape and disposition of the macronucleus; the length of the stalk; the freshwater environment; and their being epibiotic (Warren 1986).

Epibionts of the genus Cothurnia
The ciliates were loricated, and stalked. The lorica was narrow and elongated, cylindrical and rounded posteriorly (32.6-65.3 mm long, 17.3-28.9 mm wide). The individuals were attached aborally by the stalk. In the posterior end, the lorica was connected through an endostyle with the cellular body. The opposite end of the lorica contained the apical aperture, which was elliptical when viewed from above, generally wider than the width in the middle zone. The retracted body (15.4-40.3 mm long, 13.4-21.1 mm wide) occupied almost half of the lorica. The macronucleus was ovoid and located in the anterior half of the These ciliates belong to the genus Cothurnia (Warren and Paynter 1991;Lynn and Small 2000). The ciliates found were similar to those of Cothurnia compressa Claparède and Lachmann, 1858 in the elliptical lorica aperture, when viewed from above. The lorica aperture border had two deep clefts. The external stalk was short, the endostyle was short and broad, and mesostyle was absent (Warren and Paynter 1991). However, there were differences in respect to the dimensions: the length and width of the lorica are higher in C. compressa as is the size of the contracted zooid. In addition, C. compressa has been found in marine environments.

Epibionts of the genus Amphileptus
The ciliates had a lanceolate-shaped body, laterally compressed (42.2-103.7 mm long, 19.2-49.9 mm wide). There were two oval macronuclei (each 13.4-25 mm long, 5.8-15.4 mm wide). There was a spherical micronucleus located between the macronuclei, 10-12 right somatic kineties and one to four left somatic kineties. A contractile vacuole was located at the posterior end of the body. There were numerous extrusomes located over the surface, each 2.9-8.1 mm long (Table VII; Figures 2g, 18).
These ciliates belong to the genus Amphileptus (Lynn and Small 2000). The species most similar to these ciliates was Amphileptus fusidens (Kahl, 1926). They have in common the length of the body, the rounded caudal end, and the number of right and left somatic kineties (Song and Wilbert 1989;Lin et al. 2005). The rotifers belong to the genus Embata (Segers 2002). They are most similar to E. laticeps (Murray, 1905). This has straight spurs, directly posteriorly, a slender body with a transparent integument, a long foot and five segments. The teeth were 2/2 and were 508-635 mm long. It has been found on crustaceans (Koste and Shiel 1986).

Distribution of the epibionts
Twenty-five per cent of the infested shrimps were ovigerous females. The number of epibionts per basibiont fluctuated between 14 and 1114 (mean 314.6). Only 0.45% of these epibionts were rotifers, the ciliate protists representing the highest proportion of the mean density of epibionts (Table IX). Among the ciliate epibionts, the species with the highest density were Zoothamnium intermedium and Acineta sulawesiensis, which represented 94.2% of the mean epibiont density (Acineta showed the highest proportion, 59.94%). The other ciliate species accounted for 5.33% of the mean epibiont density on the shrimps (Table X). Table XI shows the numbers of epibionts on each anatomical unit of C. ensifera. Antennulae, antennae, maxillipeds, and uropods were the units with the highest mean numbers of epibionts. Table XI includes the numbers of protozoan species on the anatomical units of the shrimp. The numbers of each epibiont species on the different anatomical units of C. ensifera can be seen in Table XII. The most abundant species, Z. intermedium and A. sulawesiensis, were also the most widely distributed on the surface of the shrimp. The rotifer, although occurring in low numbers, was widely distributed on the basibiont.
The statistical comparison between the distributions of the epibiont species on the body of C. ensifera indicated a significant difference between the species (F, 11.05; P(0.05). The Principal Component Analysis performed using the mean numbers of the epibiont species on the anatomical units of the shrimp showed, in the plot of the two first principal components, two clusters, one with Amphileptus fusidens, Vorticella globosa, and Spelaeophrya polypoides, and another including Z. intermedium, A. sulawesiensis, Podophrya maupasi, and Embata laticeps. This second cluster included the epibiont species that were most common on the basibiont; the first cluster contained species that were more scarce. The ciliate Cothurnia compressa was separate from both clusters. This may be explained by its presence on the end of the basibiont body in low densities ( Figure 20). The Hierarchical Conglomerate Analysis produced a dendrogram using the mean numbers of the different epibiont species on the anatomical units of the shrimp. The units appeared grouped in five clusters (Figure 21). A cluster corresponded to the antennulae, antennae, and uropods (18.75% of the anatomical units). These units had a high number of epibionts (mean 15.80 epibionts per unit). The second cluster included 46.88% of the anatomical units (rostrum, eyes, second right pereiopod, third, fourth and fifth pereiopods, fourth and fifth pleopods, and telson); these units showed the lowest number of epibionts (mean 2.87 epibionts per unit). The third cluster consisted of the rest of pleopods (first, second and third pleopods, 18.75% of the units) which had a moderate number of epibionts (mean 8.27 per unit). In the fourth cluster were the first and left second  pereiopods (9.38% of the units), with a mean of 9.26 epibionts per unit. The fifth cluster corresponds to the maxillipeds (6.25%), the units with the highest infestation (mean 49.6 epibionts per unit). The dendrogram obtained with the mean numbers of the epibiont species on the anatomical units of the shrimp showed four clusters, each corresponding to two species, which followed a similar pattern of distribution: Z. intermedium-E. laticeps, P. maupasi-A. sulawesiensis, S. polypoides-A. fusidens, and C. maupasi-V. globosa (Figure 22).
With respect to the sum of numbers on the anatomical units of C. ensifera, the species contributing most to the total variance of the length and width of the shrimp was A. sulawesiensis. The sum of epibionts on each anatomical unit of the different shrimps showed that, in relation to the epibiosis, the unit most contributing with the maximum variance was the right antennula. Its contribution represented 75% of the total variation in length of shrimps. With respect to the width, the maximum variance corresponded to the left antennula. Its contribution represented 60.53% of the total variation in width of shrimps.
The Comparison Analysis of the epibiosis on left and right units indicated that there was no significant difference between these units when considered as pairs. On the other hand, the distribution is similar in antennulae, antennae, maxillipeds, first, second, third and fifth pereipods, first, second, third and fourth pleopods, and uropods, and these showed a significant correlation between left and right appendages. The Multiple Comparison Analysis between the units of the left side of the shrimp indicated a significant difference among them (F, 8.14; P(0.05). Also, there was a significant difference with respect to the right side (F, 7.40; P(0.05).
Distribution throughout the longitudinal axis of Caridina ensifera Figure 23 shows the mean proportion of different epibiont species and the total epibiont mean proportion along the anteroposterior axis of the shrimp. Anatomical units were considered in five groups (rostrum, antennae, antennulae, and eyes; maxillipeds; pereiopods; pleopods; uropods and telson). Z. intermedium was distributed mainly on the posterior half of the body, especially on the pleopods where it represented 50.48% of the epibionts. Also, it was found attached to the pereipods (18.3%) and the maxillipeds (15.4%). In contrast, A. sulawesiensis was more abundant on the anterior part of the shrimp, and 73.90% of the epibionts were located on the maxillipeds (43.2%), rostrum, antennae,  antennulae, and eyes. C. compressa and V. globosa were more numerous towards the posterior end of the body, where they accounted for 68.8 and 39% of epibionts, respectively, although V. globosa was remarkably numerous on the pereipods (35.3% of the epibionts). S. polypoides was more abundant on the anterior part of the body (rostrum, antennae, antennulae, and eyes) (77.9%). P. maupasi mainly colonized the maxillipeds, and A. fusidens the ends of the body, while E. laticeps was distributed on the anterior end, pereiopods, and pleopods. The epibiont community was distributed following a pattern in which the species occupied the places with behaviour of ensemble, with each species showing a distinctive distribution along the basibiont body. There was no significant correlation among the epibiont species, but a significant difference among them (F, 5.98; P(0.05). The total count data indicated that no zone on the anteroposterior axis of the shrimp showed a remarkable difference in colonization; the areas fluctuated between  11.02% on the posterior end and 31.67% on the maxillipeds. The anterior region (rostrum, antennae, antennulae, eyes, and maxillipeds) of the basibiont accounted for 54.37% of the colonization. Pereiopods, pleopods, uropods, and telson accounted for 45.63% of the colonization.
The distribution of the epibiont species on the different body areas along the longitudinal axis of C. ensifera is shown in Figure 24. As in the distribution throughout the longitudinal axis in five groups of anatomical units of the shrimp, here there was a significant difference between the distribution of the different epibiont species (F, 5.07; P(0.05).

Rotifer epibiont
Embata laticeps (Murray, 1905) Lake Poso, S shore C. ensifera constitute adaptations to the epibiont life. For example, Acineta sulawesiensis has the lorica as a free anterior part over the body enveloping the tentacles, possibly protecting them from possible damage caused by the movement of the basibiont. Other ciliates, such as Cothurnia, are protected by a lorica completely surrounding the body, and with a noticeably short stalk, which allows the ciliate to settle close to the surface of the basibiont. Something similar occurs in Podophrya which, in contrast to the free-living species, has a very short stalk. Zoothamnium has a broad stalk, which is noticeably wider on Caridina lanceolata. This not only protects the stalk, but also the colony (Fernandez-Leborans et al. 2006a). The genus showing the most obvious adaptation to the epibiont life is Spelaeophrya. Although it is lacking a conspicuous lorica, the body is flattened, and in the posterior area the body can be folded, resting next to the surface of the antennae, where these suctorians are most abundant. In several individuals, the macronucleus was considerably flattened, and its anterior part can appear widened, probably due to the adoption of the ciliate of a squashshape reducing the friction by the linkage with the surface of the appendages of the shrimp. These ciliates have only been found as epibionts on crustaceans.
The distribution of epibiont species on C. ensifera followed a gradient from the anterior to the posterior end of the body, and the maximum colonization corresponded to the anterior areas of the body, without significant differences between the left and right appendages. This phenomenon was also observed in the epibiont communities of C. lanceolata and could be correlated to the behaviour of the shrimp (Fernandez-Leborans et al. 2006a). Like C. lanceolata in the Malili lake system, C. ensifera is abundant and widely distributed in Lake Poso and often found in pelagic swarms (K. von Rintelen, personal field observation).  Koste and Shiel 1986;May 1989;Settele and Thalhofer 2003;present study Its rapid and characteristic feeding behaviour, as described for Caridina in general (Fryer 1960), along with its high mobility mainly brings the anterior part (i.e. the feeding appendages) of the shrimp into contact with different kinds of soft and hard substrates (rocks, wood, sand, macrophytes). This was similarly observed in C. lanceolata from the Malili lakes (Fernandez-Leborans et al. 2006a). In addition, the physical characteristics of the basibiont surfaces and their morphology were important for colonization. In the anterior part of the body, the surface of the antennulae and antennae provide substrata for the settlement of epibionts and the movement of these appendages facilitates the colonization. Other units with high densities of epibionts, for example the maxillipeds, showed three characteristics which possibly explain the remarkable epibiosis: the wide available surface, the protected location of these appendages, and the frequent presence of nutrient particles due to their function. Other morphological sites with high epibiosis were the uropods, possibly due to their wide exposed surface, and their position in the body with an important passage of organic material from the digestion and movement of the shrimp.
Many sessile organisms depend upon the characteristics of the living subtratum to which they adhere (Gili et al. 1993) and, therefore, the structure, dynamics, physiology, and ecology of the basibiont reflect the colonization pattern of the epibiont species, and the development of the protozoan and invertebrate communities. Epibiosis may contribute to the discernment of important aspects of the biology of the basibiont. The density and distribution of epibionts on the different anatomical units of the basibiont can indicate terminal moult, seasonal differences of moult pattern between the two sexes, the asynchronic moult between populations of different geographical areas, burying and feeding behaviours, etc. (Bottom and Ropes 1988;Abelló et al. 1990;Abelló and Macpherson 1992;Gili et al. 1993;Fernandez-Leborans et al. 1997).
Lake Poso showed a high density and diversity of epibiont species, mainly ciliate protozoans, while the density of other epibionts was less than 1%. The statistical data showed that the different epibiont species had a distinctive distribution on the basibiont, involving the differential presence of epibiont species on the anatomical units of the shrimp, and the pattern of distribution along the longitudinal axis of the basibiont which varied significantly between species. However, the community seems to show a certain pattern of behaviour by ensemble, which can be verified by their colonization pattern. The species tend to occupy the available substratum, with particular requirements of each functional group, but with a general trend towards equilibrium among species and groups, compensating for diversity and density.
The protozoan ciliate epibionts probably do not harm the basibiont. Within the epibiont community there are diverse trophic links and, therefore, as happens in free environments, there is a sort of energy feed-back (microbial loop or other relations), and several species can feed on other protozoans that are present in the epibiotic community, or on other organisms belonging to the community associated to the host (that have free movement around the basibiont), as, for example, suctorians feed on other ciliates. Peritrich ciliates could depend on the nutrients arising from the activities of the shrimp. Protozoa of lake environments are considered as a major link in the limnic food web and they have key functions in energy flow and cycling in freshwater ecosystems. Protozoa are a very important link in the transfer of energy to the higher trophic levels and they are a common nutrient for crustaceans and fish larvae (Porter et al. 1985). The changes in the community structure of protozoa may significantly affect other components of the aquatic food web, and thus may influence the distribution and abundance of both lower and higher organisms (Beaver and Crisman 1989;Cairns and McCormick 1993;Carrick and Fahnenstiel 1992). Ciliates have important ecological significance in free environments, especially in benthic areas, where they show high growth rates and an important trophic diversity (Patterson et al. 1989;Fenchel 1990;Fernandez-Leborans and Fernandez-Fernandez 2002). On a small scale, these conditions could be transferred to an epibiotic community, which could reflect the biodiversity of the environment (Fernandez-Leborans and Gabilondo 2006). The basibiont represents a dynamic environment in which the epibiont community species acquire a colonization pattern. The species were located following a particular strategy. Independently of the present species and in all cases, each species has established a similar pattern of distribution.