11th ICRS Abstract book - Nova Southeastern University

Oral Mini-Symposium 11: From Molecules to Moonbeams: How is Reproductive Timing Regulated in Coral Reef Organisms?
11-21
Spatial Patterns Of Reproductive Synchrony By Four Genera Of Tropical Green
Seaweed Across A Latitudinal Gradient in The Caribbean.
Kenneth CLIFTON* 1
1 Biology, Lewis and Clark College, Portland, OR
Spatial and temporal patterns of reproductive effort are an especially significant feature
of fertilization success for virtually all broadcast spawning organisms. While most
research efforts on this topic have focused on varying temporal scales of reproductive
synchrony (i.e., diel, lunar, and seasonal scales), patterns of reproductive synchrony on
varying spatial scales (i.e. from meters to hundreds of kilometers) are less well studied.
Simultaneous investigations of sexual reproduction by tropical green seaweeds (e.g.,
Caulerpa, Halimeda, Penicillus, Udotea) across a latitudinal gradient in the Caribbean
(Panama, U.S. Virgin Islands, Florida) reveal patterns of reproductive synchrony on
different spatial scales. Within a region, spatial synchrony often extends beyond local
populations (meters to tens of meters) to at least scales of tens of kilometers, however,
such synchrony is not maintained across larger (hundreds of kilometer) spatial scales.
Relative synchrony within and between genera is maintained across this larger latitudinal
gradient, however. Reproductive seasonality also shows an interaction with latitude for
these seaweeds, with shorter, temporally delayed seasons of reproductive activity
occurring at higher latitudes.
11-22
Genetic, Spatial And Temporal Patterns Of Spawning in The Caribbean
Montastraea Annularis Species Complex
Don LEVITAN* 1 , Nancy KNOWLTON 2
1 Biological Science, Florida State University, Tallahassee, FL, 2 Department of
Invertebrate Zoology, Smithsonian Institution, Washington, DC
Members of the Montastraea annularis species complex all spawn on the same few
evenings each year. Montastraea franksi spawns approximately 100 minutes after sunset
and M. faveolata and M. annularis overlap in spawning approximately 200 minutes after
sunset. These latter two species have incompatible gametes, whereas M.franksi and M.
annularis gametes are compatible when corals are manipulated to spawn simultaneously.
Here we investigate patterns and consequences in spawning times within a species. What
factors influence spawning times and what are the consequences of spawning early or late
within a conspecific spawning event? We have mapped and genotyped over 350
individual corals on a reef off of Bocas del Toro, Panama. These tagged corals have been
monitored for spawning over the past six years. The results indicate that (1) putative
clone-mates produced via fragmentation have more similar spawn times than unrelated
genotypes, (2) corals in deeper water tend to spawn earlier, and (3) there is a genotype by
depth interaction in spawning times (clone-mates have significant differences in the way
they respond to depth in spawn time). In addition although the species tends to spawn
over a period of approximately 40 minutes, (4) individuals corals tend to spawn within a
few minutes of when they spawned in previous years; individuals have a high degree of
fidelity to a particular spawn time. Overall these results suggest a large genetic
component to precise spawn times. Data on reproductive success of corals that spawn at
different times indicate that (5) corals spawning during the mid-point of the event have
higher reproductive success compared to individuals spawning at the tails of the event.
The genetic control over spawning time coupled with the fitness consequences of
variation in spawning times provide the evolutionary mechanism by which reproductive
synchrony is achieved.
11-23
Correlated Evolution Of Life-History Traits in Scleractinian Corals
Alexander KERR* 1,2 , Andrew BAIRD 2 , Terry HUGHES 2
1 Marine Laboratory, University of Guam, Mangilao, Guam, 2 ARC Centre of Excellence for
Coral Reef Studies, James Cook University, Townsville, Australia
The population and quantitative genetic aspects of life-history traits receive considerable
theoretical and empirical attention, yet far less is known about the macroevolutionary
relationships among such characters, particularly in a phylogenetic context. In this study, we
examine the evolution of two important life-history features, sexuality and reproductive mode,
on a composite or “supertree” phylogeny of 242 species of scleractinian corals in order to
address the following questions: (1) How rapidly do reproductive traits evolve? (2) Are the
evolutionary rates of reproductive characters correlated? (3) How does trait evolution generate
large-scale taxonomic patterns in reproductive traits? Both maximum likelihood-based model
selection and maximum-parsimony mapping of state transitions done over a sample of optimal
trees to incorporate phylogenetic uncertainty indicate that the evolution of sexuality
(gonochorism versus hermaphroditism) and reproductive mode (brooding versus spawning)
were unambiguously correlated across Scleractinia. Transition rates between states differed
significantly and by as much as two orders of magnitude among, as well as within, characters.
Reproductive mode evolves at twice the rate of sexuality, while the evolution of sexuality was
heavily biased: Gonochorism is over 100 times more likely to be lost than gained and then only
among brooders, such that gonochoric spawners seldom evolve hermaphroditism. Gonochoric
spawners preferentially shift to brooding and then, or jointly, become hermaphroditic before
reacquiring spawning to attain the dominant scleractinian reproductive condition. Thus, we
conclude that large-scale taxonomic and phylogenetic patterns in a fundamental life-history
character may be accentuated by correlated evolution with other life-history traits when coupled
by state bias in at least one character. Further, phylogenetic and taxonomic patterns of joint
character states can be generated through unanticipated and extended pathways of state change
if traits are under intense natural selection.
11-24
The Reproductive Biology Of Pacific Island Corals: Patterns And Permutations
Robert RICHMOND* 1
1 Kewalo Marine Laboratory, University of Hawaii at Manoa, Honolulu, HI
Data and observations on reproductive characteristics are available for approximately 220
species of scleractinian corals world wide. Only 10 coral species have been identified as having
year round production of gametes and larvae, and all of these are brooders. The remaining
200+ species have been identified as having limited periods of reproductive activity each year,
from a few nights or days per year, to several periods over several months. Two decades of data
on coral reproduction in the Pacific Islands of Hawaii and Micronesia have revealed annual,
lunar and diel patterns in timing as well as reproductive responses to both natural and
anthropogenic disturbances. Many of the mass spawning species including those in the genera
Acropora, Goniastrea, Favia, Porites and Leptoria have distinct temporal patterns during the
days or nights on which they spawn. Repeated sampling has demonstrated species will release
gametes consistently at specific times of day, evening or night year after year. Variability in
annual reproductive cycles has been found in response to climatic conditions and events.
Recent research on the effects of multiple stressors on corals has found reproduction is affected
by both exogenous and endogenous factors and that reproductive patterns can be interrupted or
otherwise affected by pollution and other sources of stress. Reproduction and subsequent
recruitment are the two processes responsible for the persistence of coral reefs, and as such, are
important processes for addressing the future of these precious ecosystems in the face of
mounting levels of anthropogenic disturbances including global climate change.
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