M. tuberculata Food Preference in Volusia Blue Spring
1. Melanoides tuberculata (Müller, 1774)
food preference when grazing on
Vaucheria geminata, Melosira varians and
Oscillatoria found in Volusia Blue Spring
Shantinique “Kionna” Graves
Mentor: Dr. Work
http://ts3.mm.bing.net/th?id=H.4929270748479614&w=266&h=181&c=7&rs=1&pid
=1.7
2. Exotic/Invasive species
• What is an exotic species?
– Any plant or animal species that has been introduced into
an area where they do not naturally occur. Termed: Non-
native ("U.S. Fish & Wildlife Service.")
– Invasions of ecosystems by exotic species are increasing,
especially in aquatic ecosystems (Byers, 2000)
http://www.aquaesfera.org/atlas/
d/5686-4/Melanoides-
tuberculata-12.jpg
3. Exotic/Invasive species
• Impact
– Predation – exotic crab prey on native snail (Edgell
and Rochette, 2008)
– Competition – invasive snail outcompeted native,
aiding in invasion (Byers, 2000)
– Indirect effects – looked at all invasive species as a
whole, where you can get total eradication, tolerance,
consideration of being a “new” species and overall
enrichment to ecosystems: helpful or harmful
(Walther, Gian-Reto, et al., 2009)
• Nutrient recycling
• Selective grazing
6. Occurrences
• M. tuberculata is originally a native to tropical and subtropical regions
of Africa and Asia (Wingard et al. 2008; Clench, 1969; Neck, 1985).
They became exotic through release from the aquarium trade, in which
they were imported for in the early 1930’s.
Black = present, Blue = widespread, Red = localized, Green = distributed
within a country, Yellow = few reports of being occasionally seen
https://taxo4254.wikispaces.com/file/view/Global%20distribution%20of%20MT.jpg/530325582/616x332/Global%20distribution%20of%20MT.jpg
8. Purpose
• Impact of exotic species
– Predation
– Competition
– Indirect effects
• Nutrient recycling
• Selective grazing
9. Volusia Blue Spring State Park
• M. tuberculata likes to live
in areas humans inhabit
• Prefer areas that have
slow or stagnant flow
• Cause for concern:
– Exotic
– Host for parasitic flukes
(liver and lung)
– Effect on the biological
landscape (ecosystem)
10. Volusia Blue Spring algal blooms
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http://www.landcarer
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assets/image/0019/62
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owney_melosira_1.jpg
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http://oceandatacenter.ucsc.edu/PhytoGaller
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11. Grazing
• It is an aquatic herbivorous snail that feeds
on benthic and epiphytic algae
– Mainly eat algae, such as microalgae
(diatoms)
– Can also eat detritus and organic particles that
are deposited on the sediments (detritivore)
(Subda Rao and Mitra, 1982)
– Generalist?
12. Hypothesis
• Does M. tuberculata have a
food preference for one of
the dominant algae found in
Volusia Blue Springs State
Park?
• We hypothesized that M. tuberculata
would have a food preference for
Vaucheria geminata.
16. Results
• M. tuberculata had a food preference
– for Vaucheria geminata
Figure 1. Overall average algae wet weight loss after the experiment
Snails: p < 0.0001, Algae: p < 0.0001, Interaction: p =0.033
17. Does preference change with
type of algae present?
• We wanted to know if placement mattered
among the algae
• With and without snails
18. Figure 2. Vaucheria algal wet weights compared to
Melosira and Oscillatoria with and without snails.
P = 0.541 Not Statistically Significant
19. Figure 3. Melosira algal wet weights compared to
Vaucheria and Oscillatoria with and without snails
P < 0.0001 Statistically Significant
20. Figure 4. Oscillatoria algal wet weights compared to
Vaucheria and Melosira with and without snails
P < 0.24 Not Statistically Significant
21. Discussion
• Does M. tuberculata have a food
preference for one of the algae found
in Volusia Blue Springs State Park?
– Supported
• Interesting finding:
– Placement in treatments was important
22. Discussion Cont.
• Placement was important
– Vaucheria was the most eaten and
placement did not matter
– Oscillatoria was the least eaten and
placement did not matter
– However, placement mattered when it
came to Melosira
• More Melosira was consumed when
Oscillatoria was present than Vaucheria
23. Future research
• Do they eat other types of algae?
• Growth on different types of algae
• Patterns of algal growth and proximity
of Melanoides to different taxa
• Competition?
• Larger sample size
25. Work cited
Benson, A.J., and M.E. Neilson. (2014) Melanoides tuberculata. USGS Nonindigenous Aquatic Spesies Database, Gainesville, Fl.
http://nas.er.usgs.gov/queries/FactSheet.aspx?SpeciesID=1037 Revision Date: 2/28/2013 (Accessed 14 March
2014)
Byers, J.E. (2000) Competition between Two Estuarine Snails: Implications for Invasions of Exotic Species. Ecology 81(5):
1225-1239
Clench, W.J. (1969) Melanoides tuberculata (Muller) in Florida. Nautilus 83: 72
Dundee, D.S., (1974) Catalog of introduced mollusks of eastern North America (north of Mexico). Sterkiana 55: 1-37
Edgell, T.C. and Rochette, R. (2008) Differential snail predation by an exotic crab and the geography of shell-claw covariance in
the Northwest Atlantic. Evolution 62(5): 1216-1228
Murray, H.D., (1971) The introduction and spread of thiarids in the Unites States. The Biologist 53(3): 133-135
Neck, R.W. (1985) Melanoides tuberculata in extreme southern Texas. Texas Conchologist 21(4): 150-152
"U.S. Fish & Wildlife Service." FAQs. N.p., n.d. Web. 06 Apr. 2015.
Walther, Gian-Reto, et al. (2009) "Alien species in a warmer world: risks and opportunities." Trends in ecology & evolution
24(12): 686-693.
Wingard, G.L., Murray, J.B., Schill, W.B., Phillips, E.C. (2008) "Red-Rimmed Melania (Melanoides tuberculatus) - A Snail in
Biscayne National Park, Florida - Harmful Invader or Just a Nuisance?" USGS United States Geological Survey
http://pubs.usgs.gov/fs/2008/3006/pdf/fs2008-3006.pdf (Accessed 13 February 2014)
