New Zealand Journal of Marine and Freshwater Research abstracts
+Corresponding author.
M00024Received 12 May 2000;
accepted 2 August 2000
Do potential predators induce an avoidance response in Daphnia
carinata?
AMBER C. HENDRY*
CAROLYN W. BURNS+
Department of Zoology
University of Otago
P. O. Box 56
Dunedin, New Zealand
email: carolyn.burns@stonebow.otago.ac.nz
*Present address: 4 Cecil Road, Epsom, Auckland, New
Zealand.
Abstract Chemicals exuded by predators (kairomones) are known
to induce the daytime descent of several species of Northern Hemisphere
Daphnia. The vertical migration of New Zealand's native Daphnia
carinata King has not been studied, however, and its response to kairomones
is not known. We compared the behavioural responses of D. carinata to
water from around two predatory fish, common bully (Gobiomorphus
cotidianus) and inanga (Galaxias maculatus), an aquatic insect
(Anisops wakefieldi), and several concentrations of trimethylamine
(TMA), a fish-mediated chemical. The responses of Daphnia were assessed
in nine trials by comparing their vertical distribution in cylinders of water
before and after exposure to water that had contained each predator, or TMA.
D. carinata did not alter their vertical distribution in response to
water from around Anisops. However, they descended when exposed to water
from around inanga in 83% of trials and common bully in 67% of trials. They
also descended in response to TMA in the range, 112.5-500 μM.
Analysis of these "fish waters" failed to detect TMA at
>=20 μM, so that we cannot conclude that the behavioural cue
from these fish is TMA.
Keywords vertical migration; predator avoidance;
trimethylamine; Daphnia; fish; TMA; Galaxias;
Gobiomorphus; Anisops
New Zealand Journal of Marine and Freshwater Research, 2001, Vol. 35: 155-164
0028-8330/01/3501-0155 $7.00 (c) The Royal Society of New Zealand 2001
PDF file of entire paper: medium quality (742K); (scanned from paper original: notes about this process)
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