lytechinus variegatus presentation
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Lytechinus variegatus• Variegated sea urchin
• Found in the Atlantic
Ocean and Caribbean
Sea
• Generalist grazers
• We hope to determine
feeding behaviors of L.
variegatus before and
after periods of
undernourishment
lookfordiagnosis.com (Beddingfield and McClintock 1997)
(Souza et al. 2008)
Macroalgae
Dictyota dichotomaCaulerpa verticillata
Hypnea musciformis• Important for primary
productivity on reefs
• Subject to daily grazing
(Fong and Paul 2011) (Hay and Fenical 1988)
Chemical Deterrents• Terpenoid compounds are found in varying
quantities in many different species of algae
• Phlorotannins are specific to brown algae
• These types of chemical defenses are
utilized by algae to protect them against
herbivory
(Hay and Fenical 1987)
Experiments• Experiment #1
o Fed L. variegatus while performing the experimental feeding trials with
algae
• Experiment #2o Starved L. variegatus for four days and performed the feeding trials
looking for change in feeding behaviors
• Preference Experimento The fourth tank during both experiments looked for preference of algae
when all food sources were presented to L. variegatus
Hypotheses• Experiment #1
o H0: L. variegatus will not consume any one genera of algae more than any other food source provided
o Ha: L. Variegatus will consume more C. verticillata in comparison to the other food sources provided
• Experiment #2o H0: Algal consumption will not increase after the starvation of
L. variegatus
o Ha: Algal consumption will increase after the starvation of L. variegatus
• Preference Tank o H0: L. variegatus will not favor live rock
o Ha: L. variegatus will favor live rock
Weighing Methods• Algae is laid out and patted
dry to remove a majority of
excess water
• Each algae is weighed to
equivalent amounts before the
experiments
• At the end of the experiments
the algae is siphoned from the
tanks and collected to be
reweighed
• Algae is laid out and patted
dry to remove excess water
• Look for change in weights
0
5
10
15
20
25
30
35
40
45
Brown Red Green All
Per
cen
t E
ate
n (
%)
Algae Types
Fed
Unfed
Results
Figure 1 shows the average percent algae eaten (±SE) by L. variegatus during the two experiments: Fed and Unfed
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Brown Red Green All
Ma
ss e
ate
n (
gra
ms)
Algae Types
Fed
Unfed
Results
Figure 2 shows the total mass of each alga consumed (±SE) by L. variegatus during the two experiments: Fed and Unfed
• Lytechinus variegatus prefers Caulerpa verticillata
over the other algae presented to it!
• The type of algae that L. variegatus prefers in our
experimental trials indicates what it may eat in its
natural habitat
• There is not a change in feeding in a majority of the
experiments after a period of undernourishment of
L. variegatus
• L. variegatus avoided algae with known
allelochemicals (Dictyota dichotoma)
o Covering behavior (Verling et al. 2008)
Hypotheses• Experiment #1
o H0: L. variegatus will not consume any one genera of algae more than any other food source provided
o Ha: L. Variegatus will consume more C. verticillata in comparison to the other food sources provided
o Reject H0
• Experiment #2o H0: Algal consumption will not increase after the starvation of L.
variegatuso Ha: Algal consumption will increase after the starvation of L.
variegatuso Accept H0
• Preference Tank o H0: L. variegatus will not favor live rock o Ha: L. variegatus will favor live rock o Accept H0
Future Research• Souza et al. 2004 experiments looking at two
species of each genera of algae
o These types of experiments are possible and display results
with statistically significant results
o Observed changes in feeding preferences over various periods of time and how behaviors changed
o Changes in consumption depending on time spent on a
food source
o The pattern of consumption by most popular sources goes
Chlorophyta > Rhodophyta > Phaeophyta
References• Beddingfield, S.D., McClintock, J.B., (1998) Differential survivorship,
reproduction, growth and nutrient allocation in the regular echinoid
Lytechinus variegatus (Lamarck) fed natural diets. Journal of
Experimental Marine Biology and Ecology 226, 195-215.
• Fong, P., and Paul, V.J., (2011) Coral Reef Algae. Coral Reefs: An Ecosystem in
Transition. 241-272.
• Hay, M.E., Fenical, W., and Gustafson, K., (1987) Chemical Defense Against
Diverse Coral-Reef Herbivores. Ecology 68, 1581-1591.
• Hay, M.E., and Fenical, W., (1988) Marine Plant-Herbivore Interactions: The
Ecology of Chemical Defense. Annual Review of Ecology and
Systematics 19, 111-145.
• Souza, C. F., de Oliveira, A.S., and Pereira, R.C., (2008) Feeding Preference Of
The Sea Urchin Lytechinus variegatus (Lamarck, 1816) On Seaweeds.
Brazilian Journal of Oceanography 56, 239-247
• Verling, E., Crook, A. C. & Barnes, D. K. A. 2004. The dynamics of behavior in
dominant Echinoid populations from American and European West
coasts. Marine Ecology 25, 191-206.
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