Fungiid budding and population dynamics

[James Gilmour]

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.
Regards,
James

1.	Abe, N. Growth of Fungia actiniformis var. palawensis Doderlin and its 
environmental conditions. Palao Tropical Biological Station Studies 37, 
105-145. 1923.
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, 
72-80. 1994.
	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. 
1983.
	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, 
527-534. 1992.
	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.




***  PLEASE NOTE NEW PHONE NUMBER: 08 93807192  ***

James Gilmour
Department of Zoology
University of Western Australia
Nedlands, W.A. 6907
Australia
Ph   +61 08 93807192
Fax +61 08 93801029