Predatory behaviour and metabolic costs in the Antarctic muricid gastropod Trophon longstaffi
Aquarium-based observations of the feeding
behaviour of the Antarctic muricid gastropod Trophon
longstaffi over a 3-year period revealed that individuals
were capable of feeding on both bivalve (Laternula
elliptica and Yoldia eightsi) and brachiopod (Liothyrella
uva) prey. Feeding activity was remarkably
infrequent, with most individuals taking between 0.67
and 2.66 items per year, but two individuals ate
nothing for 30 months and another ate nothing over
the entire 36-month period. The time taken to attack
and consme prey was extremely slow, with 20 days to
complete an attack on the brachiopod Liothyrella uva
and 29 days for the bivalve Laternula elliptica.
Y. eightsi were mostly attacked by a wedging method.
Most attacks were by drilling and the positioning of
large, highly distinctive drillholes was broadly stereotypic.
Metabolic rates for T. longstaffi ranged from
46.2 lg O2 h-1 for a 1.7-g tissue dry mass individual to
18.1 lg O2 h-1 for a 0.98-g tissue dry mass specimen.
These rates are amongst the lowest so far reported for
a gastropod mollusc but are within the range previously
recorded for polar invertebrates. We suggest that
T. longstaffi is well adapted for the low temperature,
but highly seasonal, Antarctic conditions, with a low
energy strategy and the ability to withstand highly
extended periods of limited food availability