Aggregation patterns of Daphnia spp. in response to the presence of kairomones from native and...
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to the presence of kairomones from native an invasive predators Approximately 50,000 invasive species have been introduced throughout the history of the United States. 5 They are a major problem and source of environmental damage. In fact, they pose such a threat to the ecosystems that $120 billion dollars are spent every year in efforts to contain them and repair their damages. 5 “Invader of the month” Bythotrephes longimanus, the spiny water flea, is a zooplanktivore originally native to Eurasia. 4 It initially invaded the Great Lakes of North America in the 1980’s via Ballast water and sediments from transatlantic cargo ships. 4 Bythotrephes is responsible, in part, for the decline in the native zooplankton populations 7 and alterations to fish diets and food web structure of lakes to which it is introduced. 6 Bythotrephes prey on smaller zooplankton such as the native Daphnia species. Daphnia are small herbivorous planktonic crustaceans native to fresh water bodies all over the world. The introduction of Bythotrephes represents an additional potential source of predation for Daphnia beyond that from fish and other native invertebrate predators such as Chaoborus spp. Will native Daphnia aggregate as a recognition response to the threat of the invasive predator Bythotrephes, or are they “naïve” ? How do Daphnia defend themselves? They recognize species specific chemical cues called kairomones. 1 When in the presence and recognition of a predator cue the prey initiates anti-predatory responses. 1 One of these responses in Daphnia is; aggregation or swarming (safety in numbers). 3 Aggregation is based on the statistical dilution of risk. 2 In order for the prey to avoid predation they must have evolved with the predator and acquired the ability to recognize these signals. Therefore, introduced predators, such as Bythotrephes, may not be recognized by native Daphnia We created an aggrega determine if they res kairomones. If they rec would swar We collected Daphnia from Lake Itasca: not been in Island Lake: has had B since 1990. The lakes differed i predator composition. We caught and harvested k fleas , phantom midges an latter two were used as c both native predators. 10 trials were repeated To analyze the data we us created on Microsoft Excel an sample assuming equal var Acknowledgments Sponsored by NSF-REU in Global Change Ecolog RISE Program 5 R25 GM059429. Brian Wisenden Ph. D, James Cotner Ph. D, specially Jessica J. Churchill who became friend that filled this summer experience w to Mark Machín-Rivera for all his uncondit Itasca Staff who have helped in the comp Adriana M. Vega-Grau, Bradley Strickland, M. Mason and Trevor Cyphers donated the making the fish kairomones. References 1 Brown W.L., Eisner Jr. T. & Whittaker R.H. 197 Messengers.” BioScience 20(1): 21-22 2 Hager M.C. & Helfman G.S. 1991 “Safety in Numb Threat.” Behavioral Ecology & Sociobiology 29(4): 3 Kleiven O.T., Larsson P., Hobaek A. 1996 “Di Predator Kairomone.” Journal of Plakton Research 4 Mclsaac H.J., Ketelaars H.A.M., Grigorovich Bythotrephes longimanus Invasions in the Great Lakes Hydrobiol. 149(1): 1-21 5 Pimentel D., Zuniga R., & Morrison D. 2005 Associated with Alien-Invasive Species in the Uni 6 Strecker, A.L., & S.E. Arnott. 2008. Invasi Jesyka Meléndez-Rosa¹, Jessica J. Churchill², Leif Hembre³, Brian Wisenden 4 ¹Department of Biology, University of Puerto Rico, Cayey. ²Department of Biology, Hamline University. ³Department of Biology, Hamline University. 4 Department of Biosciences, Minnesota State University Moorhead. To the right, photo of Bythotrephes longimanus. invasions .bio.utk. edu To the left, photo of fishing line tangled with Bythotrephes. seagrant.umn.ed u To the left, a map of the Bythotrephes invasion range. The gray areas represent the ones invaded by the zooplanktivor e. USGS Website. To the left, photo of Daphnia pulex. wild-facts.com Above, photo of Chaoborus punctipennis (The phantom midge) cfb.unh.edu To the left photo of Pimephales promelas (fathead minnow) midatlanti cstocking. com To the left, plankton net sample for D Itasca. INTRODUCTION Invasive species, why should we care? MET How did we measur kairomone Of all three kairomones, the only one that elicited a strong aggregation response in Daphnia was the fathead minnow cue. This makes biological sense because fish are visual predators and become confused when their prey aggregates. As we can see from graphs 1 & 2 the response to the cue wears off as time progresses and the swarm disperses. Daphnia from Itasca did not respond as efficiently as the ones from Island to the cue. This could be due to the fact that there are no fathead minnows present in Lake Itasca. We ask our selves again, Will native Daphnia aggregate as a recognition response to the threat of the invasive predator Bythotrephes, or are they “naïve”? NO Daphnia did not aggregate significantly in response to the spiny water flea or the phantom midge. But his RESULTS & DISCUSSION What can we learn? P value at 30s = 0.09 P value at 30s = 0.03 Above, graph 1 compares the means for the interindividual distances for Island Lake Daphnia when exposed to Fathead minnow kairomones. Above, graph 2 compares the means for the interindividual distances for Lake Itasca Daphnia when exposed to Fathead minnow kairomones. Broader Imp By identifying if ecos invasive species we can po invaders are a severe environment that monetary remedy the issue. This i large investments might species are able to adapt To the right, a diagram representing the aggregation assay method.
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Transcript of Aggregation patterns of Daphnia spp. in response to the presence of kairomones from native and...
Aggregation patterns of Daphnia spp. in response to the presence of kairomones from native and
invasive predators
Approximately 50,000 invasive species have been introduced throughout the history of the United States. 5They are a major problem and source of environmental damage. In fact, they pose such a threat to the ecosystems that $120 billion dollars are spent every year in efforts to contain them and repair their damages. 5
“Invader of the month”
Bythotrephes longimanus, the spiny water flea, is a zooplanktivore originally native to Eurasia. 4
It initially invaded the Great Lakes of North America in the 1980’s via Ballast water and sediments from transatlantic cargo ships. 4
Bythotrephes is responsible, in part, for the decline in the native zooplankton populations 7 and alterations to fish diets and food web structure of lakes to which it is introduced. 6
Bythotrephes prey on smaller zooplankton such as the native Daphnia species.
Daphnia are small herbivorous planktonic crustaceans native to fresh water bodies all over the world.The introduction of Bythotrephes represents an additional potential source of predation for Daphnia beyond that from fish and other native invertebrate predators such as Chaoborus spp.
Will native Daphnia aggregate as a recognition response to the threat of the invasive predator Bythotrephes, or are
they “naïve”?
How do Daphnia defend themselves?
They recognize species specific chemical cues called kairomones. 1 When in the presence and recognition of a predator cue the prey initiates anti-predatory responses. 1
One of these responses in Daphnia is; aggregation or swarming (safety in numbers). 3 Aggregation is based on the statistical dilution of risk. 2 In order for the prey to avoid predation they must have evolved with the predator and acquired the ability to recognize these signals. Therefore, introduced predators, such as Bythotrephes, may not be recognized by native Daphnia or other zooplankton species.
We created an aggregation assay in order to determine if they responded to the predator kairomones. If they recognized them, then
they would swarm together.
We collected Daphnia from two lakes; Lake Itasca: not been invaded by BythotrephesIsland Lake: has had Bythotrephes in its food web since 1990.
The lakes differed in types of zooplankton predator composition.
We caught and harvested kairomones from spiny water fleas , phantom midges and fathead minnows, the latter two were used as controls because they are both native predators.
10 trials were repeated per lake→
To analyze the data we used a distance matrix created on Microsoft Excel and performed t-Tests: two-sample assuming equal variances.
Acknowledgments
Sponsored by NSF-REU in Global Change Ecology.RISE Program 5 R25 GM059429.
Brian Wisenden Ph. D, James Cotner Ph. D, Sehoya Cotner Ph. D, Leif Hembre Ph. D & specially Jessica J. Churchill who became more than a research partner, she became a friend that filled this summer experience with unforgettable memories. A special thanks to Mark Machín-Rivera for all his unconditional support and to all my GCE peers and Itasca Staff who have helped in the completion of this project; Ana L. Velazquez, Adriana M. Vega-Grau, Bradley Strickland, Jasmond K. Tucker & Maria M. Hargis. Chauna M. Mason and Trevor Cyphers donated the Pimephales promelas (fathead minnows) used for making the fish kairomones.
References
1 Brown W.L., Eisner Jr. T. & Whittaker R.H. 1970 “Allomones & Kairomones: Transspecific Chemical Messengers.” BioScience 20(1): 21-222 Hager M.C. & Helfman G.S. 1991 “Safety in Numbers: Shoal Size Choice by Minnows Under Predatory Threat.” Behavioral Ecology & Sociobiology 29(4): 271-2763 Kleiven O.T., Larsson P., Hobaek A. 1996 “Direct Distributional Response in Daphnia pulex to a Predator Kairomone.” Journal of Plakton Research 18(8): 1341-13484 Mclsaac H.J., Ketelaars H.A.M., Grigorovich I.A., Ramcharan C.W., Yan D.M. 2000 “Modeling Bythotrephes longimanus Invasions in the Great Lakes Basin Based on its European Distribution.”Arch. Hydrobiol. 149(1): 1-215 Pimentel D., Zuniga R., & Morrison D. 2005 “Update on the Enviromental & Economic Costs Associated with Alien-Invasive Species in the United States.” Ecological Economics 52(3): 273-2886 Strecker, A.L., & S.E. Arnott. 2008. Invasive predator, Bythotrephes, has varied effects on ecosystem function in freshwater lakes. Ecosystems 11: 490.7 Yan N.D., Girard R., & Bourdreau S. 2002 “An Introduced Invertebrate Predator (Bythotrephes) Reduced Zooplankton Species Richness.” Ecology Letters 5(4): 481-485
Jesyka Meléndez-Rosa¹, Jessica J. Churchill², Leif Hembre³, Brian Wisenden4 ¹Department of Biology, University of Puerto Rico, Cayey. ²Department of Biology, Hamline University. ³Department of Biology, Hamline University.4Department of
Biosciences, Minnesota State University Moorhead.
To the right, photo of
Bythotrephes longimanus.
invasions.bio.utk.edu
To the left, photo of fishing line tangled with Bythotrephes. seagrant.umn.edu
To the left, a map of the Bythotrephes invasion range. The gray areas represent the ones invaded by the zooplanktivore. USGS Website.
To the left, photo of Daphnia pulex.wild-facts.com
Above, photo of Chaoborus punctipennis (The phantom midge) cfb.unh.edu
To the left photo of Pimephales promelas (fathead minnow) midatlanticstocking.com
To the left, photo of plankton net used to sample for Daphnia. Lake Itasca.
INTRODUCTIONInvasive species, why should we care?
METHODSHow did we measure Daphnia predator kairomone
response?
Of all three kairomones, the only one that elicited a strong aggregation response in Daphnia was the fathead minnow cue. This makes biological sense because fish are visual predators and become confused when their prey aggregates.As we can see from graphs 1 & 2 the response to the cue wears off as time progresses and the swarm disperses.Daphnia from Itasca did not respond as efficiently as the ones from Island to the cue. This could be due to the fact that there are no fathead minnows present in Lake Itasca.
We ask our selves again, Will native Daphnia aggregate as a recognition response to the threat of the invasive
predator Bythotrephes, or are they “naïve”?
NO
Daphnia did not aggregate significantly in response to the spiny water flea or the phantom midge. But his does not mean they are necessarily naïve. Because kairomones are species specific, Daphnia likely utilize other anti-predator behaviors when in the presence of these predators.
RESULTS & DISCUSSIONWhat can we learn?
P value at 30s = 0.09
P value at 30s = 0.03
Above, graph 1 compares the means for the interindividual distances for Island Lake Daphnia when exposed to Fathead minnow kairomones.
Above, graph 2 compares the means for the interindividual distances for Lake Itasca Daphnia when exposed to Fathead minnow kairomones.
Broader Implications?
By identifying if ecosystems are adapting to invasive species we can potentially determine if the invaders are a severe enough threat to the environment that monetary investment is needed to remedy the issue. This is important because such large investments might not be needed if native species are able to adapt naturally.
To the right, a diagram representing the aggregation assay method.
