New Zealand Journal of Marine and Freshwater Research abstracts
Mouthpart morphology of three calanoid copepods from Australian
temporary pools: evidence for carnivory
JOHN D. GREEN
Department of Biological Sciences
University of Waikato
Private Bag 3105
Hamilton, New Zealand
email: j.green@waikato.ac.nz
RUSSELL J. SHIEL
CRC for Freshwater Ecology
Murray-Darling Freshwater Research Centre
P. O. Box 921, Albury
NSW 2640, Australia
Abstract The mandibles, first and second maxillae, and
maxillipeds of
Boeckella major,
B. pseudochelae,
and
Hemiboeckella searli from temporary pools of the upper River Murray
catchment were dissected off and examined by light microscopy for features
associated with carnivorous feeding. In
B. major adaptations for
carnivory are enlarged ventral mandibular teeth, strong falciform medial setae
on the second maxillae, falciform endopodal setae on the maxilliped, large body
size and large mouthpart size in relation to body size. Its mandibular edge
index is 772, in the upper omnivore range.
B. major is predicted to be
an omnivore with strong carnivorous tendencies and able to handle large prey
items. Carnivorous features in
H. searli are enlarged ventral mandibular
teeth, a mandibular edge index of 1395, and strong unguiform and falciform
setae on the second maxillae. It is predicted to be an omnivore with moderate
carnivorous tendencies, but unable to handle prey as large as can
B.
major. In
B. pseudochelae the only adaptations for carnivory are an
edge index of 1080 and falciform setae on the maxilliped. It is predicted to be
an omnivore with herbivorous tendencies. Examination of gut contents confirmed
these predictions.
B. major guts contained 19 animal taxa, mainly
planktonic cladocerans, copepods and rotifers,
H. searli 12 taxa, mainly
copepods and rotifers, and
B. pseudochelae 8 taxa, mainly rotifers. All
had consumed algae. We suggest that predation by
B. major may be an
important factor affecting community structure in fishless Australian temporary
pools.
Keywords calanoid copepod; carnivorous; predation; temporary
pool; Australia
This paper is dedicated to Dr Ann Chapman on the occasion of her retirement.
JDG expresses his thanks to Ann for stimulating his interest in calanoid
copepods and the intricacies of their structure and
function.
M98046
Received 20 July 1998; accepted 5 October
1998
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