Fungiid budding and population dynamics
jgilmour at cyllene.uwa.edu.au
Wed Sep 20 03:42:47 EDT 2000
Dear coral listers,
there appears to be some interest in the production of asexual buds by
fungiid corals, so I thought I would share my results to date. I have
genetic, size frequency and tagging data (growth, mortality, etc) for
population(s) of Fungia fungites. I have monitored populations for 2.5
years through a mass coral bleaching (1998) and two cyclones.
In one study population, a high level of sedimentation is related to a high
frequency of bud production (60% of population). Budding results from polyp
injury, and small pieces of parent tissue in the damaged region regress
into the septa and costae (see Boschma 1923, Krupp et al. 1992).
Approximately 6-8 months later, buds are first seen by eye (0.3cm diam.),
on the top, bottom or sides of the polyp. Partial polyp mortality, in this
species at this study population, is usually followed (<6 - 12 months) by
whole polyp mortality.
Electrophoretic analysis (N = 95) indicates that most (all?) buds on
fungiid skeletons are derived asexually from the parent tissue. All buds (
n = 2- 5) sampled from a single parent ( n = 23) were the same genotype,
and three parents with some remaining tissue were the same genotype as
their attached buds. There was no genetic evidence for sexual recruitment
to dead skeletons, and, as in other studies of fungiids, I have had no
detectable recruitment to settlement plates over three mass spawnings.
Different experimental treatments, including sedimentation, have been found
to cause partial or whole polyp mortality, and therefore asexual bud
production. The number of buds per parent is probably related to the amount
of adult tissue contributing to the process. I did not, however, find any
relationship between polyp size and number of buds produced (>0.3cm
diameter), probably because of the variability in tissue damage and the
very high mortality rates of buds when first emerging. At the
sediment-affected population, mean bud size was approximately 1cm (diam.),
and buds detached from the parent at a size of approximately 2.5cm. Bud
mortality was high (67%). In contrast, sexual recruits attached to the
substrata in regions of lower sediment stress, and remained there for
longer, detaching at a size of around 6cm. Consequently, mortality rates
for sexual recruits were much lower (8%) than for asexual buds, and because
they detach at a larger size, had a much greater chance of survival given
strong size specific mortality rates in free living polyps.
I will be comparing the results obtained from size frequency, tagging, and
genetic analysis of the sediment affected population at the 9th ICRS in
Bali. Results for this, and other populations, using each of the three
methods, will be published shortly. There has been some interesting work
published on fungiids and below is a brief summary.
1. Abe, N. Growth of Fungia actiniformis var. palawensis Doderlin and its
environmental conditions. Palao Tropical Biological Station Studies 37,
2. Boschma H. Experimental budding in Fungia fungites. Proc K Ned Akad Wet
26, 88-96. 1923.
3. Chadwick-Furman, N E and Loya, Y. Migration, habitat use, and
competition among mobile corals (Scleractinia:Fungiidae) in the Gulf of
Eilat, Red Sea. Mar Biol 114, 617-623. 1992.
4. Chadwick NE, Loya Y. Regeneration aftrer experimental breakage in the
solitary reef coral Fungia granulosa Klunzinger, 1879. J Exp Mar Biol Ecol
142, 221-234. 1990.
5. Chadwick, N E. Competition and locomotion in a free living fungiid
coral. J Exp Mar Biol Ecol 123, 189-200. 1988.
6. Chandwick-Furman, N E, Goffredo, S, and Loya, Y. Growth and population
dynamics model of the reef coral Fungia granulosa Klunzinger, 1879 at
Eilat, northern Red Sea. J Exp Mar Biol Ecol 249, 199-218. 2000.
7. Jokiel, P L and Bigger, C H. Aspects of histocompatability and
regeneration in the solitary reef coral Fungia scutaria. Biol Bull 186,
8. Kramarsky-Winter E, Loya Y. Regeneration versus budding in fungiid
corals: a trade-off. Mar Ecol Prog Ser 134, 179-185. 1996.
9. Krupp DA. Sexual reproduction and early development of the solitary
coral Fungia scutaria (Anthozoa: Scleractinia). Coral Reefs 2, 159-164.
10. Krupp DA, Jokiel PL Chartrand TS. Asexual reproduction by the
solitary scleractinian coral Fungia scutaria on dead parent coralla in
Kanehoe Bay, Oahu, Hawaiian Islands. Proc 7th Int Symp Coral Reefs 1,
11. Kramarsky-Winter, E and Loya, Y. Reproductive strategies of two
fungiid corals from the northern Red Sea: environmental constraints? Mar
Ecol Prog Ser 174, 175-182. 1998.
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