2 research outputs found
Ontogenetic and gender-modulated behavioural rhythms in the deep-water decapods Liocarcinus depurator (Brachyura: Portunidae), Munida tenuimana and Munida intermedia (Anomura: Galatheidae)
13 pages, 6 figures, 2 tablesThe regulation and expression of biological rhythms with respect to sex and
ontogeny in deep-water benthic decapod crustaceans constitutes an exciting
field in marine biology that is far from understood. Liocarcinus depurator,
Munida intermedia and Munida tenuimana are ecologically key crustacean decapod
species of the Atlantic and Mediterranean shelves and slopes, and their
activity rhythms in the field are poorly known. Our aim was to measure the
behavioural rhythms of these species, while at the same time defining their type
of displacement (i.e. endobenthic, nektobenthic or benthopelagic). Whether
gender and ontogeny modulate the rhythmic behaviour of these decapods is
unknown, and we sought to clarify this issue. A temporally scheduled series of
trawl hauls and light intensity measures was performed on the western Mediterranean
shelf (100–110 m depth) and slope (400–430 m), close to the autumn
equinox and the summer solstice. The sex and the size of animals in the catches
were analysed. Catch patterns were evaluated through waveform and periodogram
analyses. Liocarcinus depurator was captured at night on the shelf, whereas
on the slope, animals displayed peaks both in the middle of the day and night.
Size-related differences (but no gender differences) were found in its rhythmic
behaviour, possibly due to intra-specific competition (e.g. fighting) between
juveniles and adults. Munida intermedia were weakly diurnal in October and
both diurnal and nocturnal in June. Munida tenuimana presented no discernible
rhythmicity in October, but was nocturnal in June. Both species showed no
evident sex or size modulation of their behaviour. Data were interpreted assuming
that all tested species present an endobenthic behaviour (i.e. animals emerge
from the substrate during the active phase of their behavioural cycle).The authors wish to thank F. Sarda` , Chief Investigator of
the project NERIT (MAR98-0935) funded by the Spanish
CICYT and the crew of the R⁄V Garcı´a del Cid (CSIC)
for their support during sampling.
J. Aguzzi is a Post-doctoral fellow in the Juan de la Cierva
Program.Peer reviewe