2 research outputs found
Biogeography of sponge chemical ecology: comparisons of tropical and temperate defenses
11 páginas, 3 figuras, 3 tablas.Examples from both marine and terrestrial
systems have supported the hypothesis that predation is
higher in tropical than in temperate habitats and that, as a
consequence, tropical species have evolved more effective
defenses to deter predators. Although this hypothesis
was first proposed for marine sponges over 25 years ago,
our study provides the first experimental test of latitudinal
differences in the effectiveness of sponge chemical
defenses. We collected 20 common sponge species
belonging to 14 genera from tropical Guam and temperate
Northeast Spanish coasts (Indo-Pacific and Mediterranean
biogeographic areas) and conducted field-based feeding
experiments with large and small fish predators in both
geographic areas. We use the term global deterrence to
describe the deterrent activity of a sponge extract against
all of the predators used in our experiments and to test the
hypothesis that sponges from Guam are chemically better
defended than their Mediterranean counterparts. Sympatric
and allopatric deterrence refer to the average
deterrent activity of a sponge against sympatric or
allopatric predators. All of the sponges investigated in
this study showed deterrent properties against some
predators. However, 35% of the sponge species were
deterrent in at least one but not in all the experiments,
supporting the idea that predators can respond to chemical
defenses in a species-specific manner. Tropical and
temperate sponges have comparable global, sympatric,
and allopatric deterrence, suggesting not only that chemical
defenses from tropical and temperate sponges are
equally strong but also that they are equally effective
against sympatric and allopatric predators. Rather than
supporting geographic trends in the production of chemical
defenses, our data suggest a recurrent selection for
chemical defenses in sponges as a general life-history
strategy.The U.S.-Spain Joint Commission
on Scientific and Technological Cooperation funded this
collaborative project between the UOGML and the CEAB. This is
contribution number 528 of the University of Guam Marine
Laboratory.Peer reviewe