Food
environment for resting egg hatchings affect mixis induction in derived
clones of the rotifer Brachionus plicatilis.
A.
Hagiwara, Y. Kadota, H. Akinori-2003
Abstract:
We
investigated the effect of food for stem females hatched from resting eggs
and their derived clones on mixis induction in a laboratory. Russian strain
Brachionus plicatilis resting eggs were hatched and reared both by batch (in
100 ml water) and individual cultures (0.2 ml) for 20 days and 10-12
generations, respectively. Cultures were maintained at 25°C, 18 ppt
salinity and total darkness. A higher percentage of mixis was observed in
rotifer populations fed solely on Nannochloropis oculata, by comparison with
those fed on baker’s yeast. In comparison to the above, mixis induction
was significantly higher for treatments in which stem females received a low
quality diet (baker’s yeast), and subsequent generations received a higher
quality diet (N. oculata). A similar trend was observed when stem females
were starved. Starvation of stem females for 12 and 24 hours after hatching
resulted in 10.2% and 7.2% of mixis induction in subsequent generations,
respectively, while it remained at 3.6% when N. oculata was consistently fed
to the rotifers.
(Graduate
School of Science & Technology, Nagasaki University, Bunkyo 1-14,
Nagasaki 852-8521, Japan, e-mail: hagiwara@net.nagasaki-u.ac.jp)