Telford (1982) described the feeding habits of four species of Dissodactylus and
found that all of them feed extensively upon their sand dollar hosts, with
50–100 % of their food intake coming from their host’s tissues. This is supported
by the fact that some M. stokesii often have multiple wounds with only a single
crab present (Fig. 4.6a).
Ecological work on ophiuroids in Panama is primarily the result of research by
Gordon Hendler. Hendler and Meyer (1982) reported the presence of the polychaete Branchiosyllis exilis (Gravier, 1900) associated with Ophiocoma echinata
(Lamarck, 1816) on the Caribbean coast of Panama. This association has only been
reported from Panama, despite the fact that both species’ distributions are overlapping and widespread. The polychaete displays active recognition of its host and
seeks out O. echinata in preference to other species of the same genus. They
consistently found one polychaete per host, indicating that B. exilis is aggressive to
member of its own species, and concluded that B. exilis is parasitic on O. echinata.
An interesting association between juvenile and adult Ophiocoma aethiops
Lütken, 1859, from Punta Paitilla in Panama was documented by Hendler et al.
(1999). Juveniles were found in the bursae (respiratory structures that in brooding
and viviparous ophiuroids also serve as brood chambers) of adults that live
intertidally at Punta Paitilla but not those that live subtidally at Isla Taboguilla.
They proposed this association helped protect juveniles against desiccation and
predators. No similar association was found in other species of Ophiocoma form
either the Pacific (O. alexandri Lyman, 1860) or from the Caribbean (O. echinata,
O. wendtii Müller and Troschel, 1842) of Panama.
Much of the ecological work on starfish in Panama has focused on Acanthaster
planci (Linnaeus, 1758) (e.g. Glynn 1973, 1974, 1976, 1977, 1981– 1985a,b,
1990). Glynn (1973) assessed the possible effect of A. planci on the coral species
on Uva Reef in the Gulf of Chiriquí. He reported an average density of 25–36 ind
ha
-1 , with a disc diameter of 17–19 cm and a size frequency that had a unimodal
distribution. Population densities of A. planci remained fairly stable on Uva Reef
from 1970 to 1980, ranging from 7 to 30 ind ha
-1 (Glynn 1981). At that time these
densities were comparable to population sizes in the Indo-Pacific that were not
considered to have a serious impact on coral communities (Glynn 1974). However,
prey preference data (Glynn 1974) indicate that A. planci selectively eats rarer
non-branching corals (e.g. species of Pavona, Gardineroseris, Porites, Millepora,
Fig. 4.7), which are replaced by faster-growing species (e.g. Pocillopora spp.),
resulting in A. planci having a negative effect on species diversity (Glynn 1976).
Such a preference can partly be explained by the presence of crustacean symbionts
(Trapezia sp. and Alpheus sp.) in large branching pocilloporid colonies which
repulse A. planci by nipping at its vulnerable oral surface (particularly the sensory
tube feet) as it attempts to mount the coral to feed (Glynn 1976).
Between 1982 and 1983 a strong El Niño-Southern Oscillation had a dramatic
impact on the coral reefs of the Eastern Tropical Pacific, causing a die off of
between 70–95 % of coral on Pacific Panamanian reefs (Glynn 1985a, b). However, population densities of A. planci before and after the 1983 event were not
statistically different (Glynn 1990), with A. planci continuing to feed on the
4 Echinoderm Diversity in Panama
117
found that all of them feed extensively upon their sand dollar hosts, with
50–100 % of their food intake coming from their host’s tissues. This is supported
by the fact that some M. stokesii often have multiple wounds with only a single
crab present (Fig. 4.6a).
Ecological work on ophiuroids in Panama is primarily the result of research by
Gordon Hendler. Hendler and Meyer (1982) reported the presence of the polychaete Branchiosyllis exilis (Gravier, 1900) associated with Ophiocoma echinata
(Lamarck, 1816) on the Caribbean coast of Panama. This association has only been
reported from Panama, despite the fact that both species’ distributions are overlapping and widespread. The polychaete displays active recognition of its host and
seeks out O. echinata in preference to other species of the same genus. They
consistently found one polychaete per host, indicating that B. exilis is aggressive to
member of its own species, and concluded that B. exilis is parasitic on O. echinata.
An interesting association between juvenile and adult Ophiocoma aethiops
Lütken, 1859, from Punta Paitilla in Panama was documented by Hendler et al.
(1999). Juveniles were found in the bursae (respiratory structures that in brooding
and viviparous ophiuroids also serve as brood chambers) of adults that live
intertidally at Punta Paitilla but not those that live subtidally at Isla Taboguilla.
They proposed this association helped protect juveniles against desiccation and
predators. No similar association was found in other species of Ophiocoma form
either the Pacific (O. alexandri Lyman, 1860) or from the Caribbean (O. echinata,
O. wendtii Müller and Troschel, 1842) of Panama.
Much of the ecological work on starfish in Panama has focused on Acanthaster
planci (Linnaeus, 1758) (e.g. Glynn 1973, 1974, 1976, 1977, 1981– 1985a,b,
1990). Glynn (1973) assessed the possible effect of A. planci on the coral species
on Uva Reef in the Gulf of Chiriquí. He reported an average density of 25–36 ind
ha
-1 , with a disc diameter of 17–19 cm and a size frequency that had a unimodal
distribution. Population densities of A. planci remained fairly stable on Uva Reef
from 1970 to 1980, ranging from 7 to 30 ind ha
-1 (Glynn 1981). At that time these
densities were comparable to population sizes in the Indo-Pacific that were not
considered to have a serious impact on coral communities (Glynn 1974). However,
prey preference data (Glynn 1974) indicate that A. planci selectively eats rarer
non-branching corals (e.g. species of Pavona, Gardineroseris, Porites, Millepora,
Fig. 4.7), which are replaced by faster-growing species (e.g. Pocillopora spp.),
resulting in A. planci having a negative effect on species diversity (Glynn 1976).
Such a preference can partly be explained by the presence of crustacean symbionts
(Trapezia sp. and Alpheus sp.) in large branching pocilloporid colonies which
repulse A. planci by nipping at its vulnerable oral surface (particularly the sensory
tube feet) as it attempts to mount the coral to feed (Glynn 1976).
Between 1982 and 1983 a strong El Niño-Southern Oscillation had a dramatic
impact on the coral reefs of the Eastern Tropical Pacific, causing a die off of
between 70–95 % of coral on Pacific Panamanian reefs (Glynn 1985a, b). However, population densities of A. planci before and after the 1983 event were not
statistically different (Glynn 1990), with A. planci continuing to feed on the
4 Echinoderm Diversity in Panama
117