Effects of Effects of Competition on Competition on
AmbystomaAmbystoma Salamander LarvaeSalamander Larvae
Erica ReedErica ReedApril 17, April 17,
20062006BIO 299BIO 299
Adult Ambystoma opacum with eggs
Ambystoma opacum larva
Background information Background information about about AmbystomaAmbystoma
salamanderssalamanders Found in temporary woodland pondsFound in temporary woodland ponds
vernal pondsvernal ponds Breed from September to NovemberBreed from September to November Eggs are deposited between Eggs are deposited between
November and JanuaryNovember and January When the ponds fillWhen the ponds fill Eggs are attached to fallen tree Eggs are attached to fallen tree
branches in the waterbranches in the water Larval period lasts 4 to 5 monthsLarval period lasts 4 to 5 months
Background information about Background information about AmbystomaAmbystoma Salamander Salamander
LarvaeLarvae Gape-limited predatorsGape-limited predators Generalist foragersGeneralist foragers
Diet includes macroinvertebrates, Diet includes macroinvertebrates, isopods, aquatic insects, and other isopods, aquatic insects, and other amphibian larvaeamphibian larvae
Capable of phenotypic plasticityCapable of phenotypic plasticity Change in an organisms phenotype in Change in an organisms phenotype in
response to their environmentresponse to their environment
Intraspecific vs. Intraspecific vs. Interspecific CompetitionInterspecific Competition
Competition Competition between between individuals of the individuals of the same speciessame species
Effects….Effects…. SizeSize AggressionAggression ForagingForaging SurvivalSurvival
Competition Competition between different between different speciesspecies Direct interferenceDirect interference Indirect interferenceIndirect interference
Competitive speciesCompetitive species TroutTrout Rana sylvaticaRana sylvatica (Wood (Wood
Frog)Frog) Aquatic insectsAquatic insects
Diving beetle larvaeDiving beetle larvae Dragonfly naiadsDragonfly naiads
INTRASPECIFIC INTRASPECIFIC COMPETITIONCOMPETITION
Effect on SizeEffect on Size Bigger is Better…in some instancesBigger is Better…in some instances
Larger individuals are able to obtain food in greater Larger individuals are able to obtain food in greater amountsamounts
Smaller individuals are better at exploitative competitionSmaller individuals are better at exploitative competition Energy RequirementsEnergy Requirements
Larger individuals require more energy, in turn more Larger individuals require more energy, in turn more food, to keep up with everyday activitiesfood, to keep up with everyday activities
Smaller individuals can use less food to gain the required Smaller individuals can use less food to gain the required energy for everyday activitiesenergy for everyday activities
Interference Interference Larger individuals show greater aggression and push the Larger individuals show greater aggression and push the
smaller individuals aroundsmaller individuals around Size differences lead to cannibalism and intraguild Size differences lead to cannibalism and intraguild
predationpredation
Effect of AggressionEffect of Aggression Aggression is a form of direct interference within a Aggression is a form of direct interference within a
speciesspecies Increases the survival and nutrient uptake of one Increases the survival and nutrient uptake of one
individualindividual Reduces growth rate of smaller individualsReduces growth rate of smaller individuals Observed most at feeding timeObserved most at feeding time Two types…Two types…
Lunge- advancement towards another individualLunge- advancement towards another individual Bite- open mouth grabbing of another individualBite- open mouth grabbing of another individual
Often leads to cannibalismOften leads to cannibalism
INTERSPECIFIC INTERSPECIFIC COMPETITIONCOMPETITION
TroutTrout Trout were introduced in to areas where Trout were introduced in to areas where
AmbystomaAmbystoma salamanders live salamanders live Trout inhibit growth, reduce survival, and Trout inhibit growth, reduce survival, and
decrease activity of decrease activity of AmbystomaAmbystoma salamander larvaesalamander larvae
Trout can reduce or even eliminate Trout can reduce or even eliminate AmbystomaAmbystoma larvae larvae
Predation is the most likely the causePredation is the most likely the cause Trout predation also shifts larval behaviorsTrout predation also shifts larval behaviors
Larvae shift to nocturnal feeding Larvae shift to nocturnal feeding Decreased food consumption and feeding efficiency Decreased food consumption and feeding efficiency
Rana sylvaticaRana sylvatica (Wood (Wood Frogs)Frogs)
Known to feed on Known to feed on AmbystomaAmbystoma eggs and eggs and exposed larvaeexposed larvae
Wood frogs effect growth rate, time of Wood frogs effect growth rate, time of metamorphosis, and survival of larvaemetamorphosis, and survival of larvae
Wood frogs and Wood frogs and Ambystoma Ambystoma larvae feed larvae feed on much of the same resourceson much of the same resources
Wood frogs do not intentionally seek out Wood frogs do not intentionally seek out egg massesegg masses
Effects of breeding bouts and the Effects of breeding bouts and the presence or absence of presence or absence of Rana Rana
sylvaticasylvatica tadpoles tadpoles Breeding bout is the Breeding bout is the
seasonal time of egg seasonal time of egg depositsdeposits
(A) shows larval (A) shows larval survival survival
(B) shows length of (B) shows length of larval stage, or time to larval stage, or time to metamorphosismetamorphosis
(C) shows mass of (C) shows mass of AmbystomaAmbystoma larvae at larvae at metamorphosismetamorphosis Holbrook and Petranka
(2004)
Effects of Effects of Rana sylvaticaRana sylvatica density and access to egg density and access to egg
massesmasses Different densities were Different densities were
tested in different poolstested in different pools
The graph shows that The graph shows that high density of high density of Rana Rana sylvaticasylvatica causes causes decreased chance of decreased chance of survival, growth, and survival, growth, and development of development of AmbystomaAmbystoma salamander salamander larvaelarvae
Holbrook and Petranka (2004)
Predation of egg masses by Predation of egg masses by Rana sylvaticaRana sylvatica tadpoles tadpoles
Tadpoles do not Tadpoles do not intentionally seek out intentionally seek out egg massesegg masses
The predation of egg The predation of egg masses was tested in masses was tested in different food availability different food availability treatments.treatments.
Rana sylvaticaRana sylvatica tadpoles tadpoles were seen to feed on egg were seen to feed on egg masses during periods masses during periods low food availabilitylow food availability
Petranka et al (1998)
Aquatic InsectsAquatic Insects
Diving Beetle LarvaeDiving Beetle Larvae Active predatorsActive predators Salamander larvae haveSalamander larvae have
Shorter snout ventsShorter snout vents Longer and deeper tailsLonger and deeper tails Weigh more than larvae Weigh more than larvae
in environments with in environments with dragonfly larvae, but less dragonfly larvae, but less than the controlthan the control
Dragonfly larvaeDragonfly larvae Sit and wait predatorsSit and wait predators Salamander larvae Salamander larvae
havehave Shorter snout ventsShorter snout vents Shorter and deeper Shorter and deeper
tailstails Weigh less than larvae Weigh less than larvae
in any of the other in any of the other environmentsenvironments
Effects of aquatic insects on Effects of aquatic insects on salamander larvaesalamander larvae
Graph shows snout Graph shows snout vent length, tail vent length, tail length and depth, length and depth, and mass of and mass of Ambystoma tigrinum Ambystoma tigrinum nebulosumnebulosum in the in the absence of aquatic absence of aquatic insects and with the insects and with the diving beetle larvae diving beetle larvae ((DytiscusDytiscus) and ) and dragonfly larvae dragonfly larvae ((AnaxAnax))
Storfer and White (2004)
Literature CitedLiterature Cited Brodman, R. 2004. Intraguild predation on congeners affects Brodman, R. 2004. Intraguild predation on congeners affects
size, aggression, and survival among Ambystoma salamander size, aggression, and survival among Ambystoma salamander larvae. Journal of Herpetology, 38: 21-26.larvae. Journal of Herpetology, 38: 21-26.
Holbrook, C.T. and J.W. Petranka. 2004. Ecological interactions Holbrook, C.T. and J.W. Petranka. 2004. Ecological interactions between between Rana sylvatica Rana sylvatica and and Ambystoma maculatumAmbystoma maculatum : : Evidence of interspecific competition and facultative intraguild Evidence of interspecific competition and facultative intraguild predation. Copeia, 4: 932-939.predation. Copeia, 4: 932-939.
Johnson, E.B., P. Bierzychudek, and H. Whiteman. 2003. Johnson, E.B., P. Bierzychudek, and H. Whiteman. 2003. Potential of prey size and type to affect foraging asymmetries Potential of prey size and type to affect foraging asymmetries in tiger salamander (in tiger salamander (Ambystoma tigrinum nebulosumAmbystoma tigrinum nebulosum) larvae. ) larvae. Canadian Journal of Zoology, 81: 1726-1735.Canadian Journal of Zoology, 81: 1726-1735.
Pearman, P.B. 2002. Interactions between Ambystoma Pearman, P.B. 2002. Interactions between Ambystoma salamander larvae: Evidence for competitive asymmetry. salamander larvae: Evidence for competitive asymmetry. Herpetologica, 58: 156-165.Herpetologica, 58: 156-165.
Petranka, J.W., A.W. Rushlow, and M.E. Hopey. 1998. Predation Petranka, J.W., A.W. Rushlow, and M.E. Hopey. 1998. Predation by tadpoles of by tadpoles of Rana sylvaticaRana sylvatica on embryos of on embryos of Ambystoma Ambystoma maculatummaculatum: Implications of ecological role reversals by Rana : Implications of ecological role reversals by Rana (predator) and Ambystoma (prey). Herpetologica, 54: 1-13.(predator) and Ambystoma (prey). Herpetologica, 54: 1-13.
Literature CitedLiterature Cited Smith, C.K. 1990. Effects of variation body size on Smith, C.K. 1990. Effects of variation body size on
intraspecific competition among larval salamanders. intraspecific competition among larval salamanders. Ecology, 71: 1777-1788.Ecology, 71: 1777-1788.
Storfer, A. and C. White. 2004. Phenotypically plastic Storfer, A. and C. White. 2004. Phenotypically plastic responses of larval tiger salamanders, Ambystoma tigrinum, responses of larval tiger salamanders, Ambystoma tigrinum, to different predators. Journal of Herpetology, 38: 612-615.to different predators. Journal of Herpetology, 38: 612-615.
Tyler, T., W. Liss, L. Ganio, G. Larson, R. Hoffman, E. Tyler, T., W. Liss, L. Ganio, G. Larson, R. Hoffman, E. Deimling, and G. Lomnicky. 1998. Interaction between Deimling, and G. Lomnicky. 1998. Interaction between introduced trout and larval salamanders (introduced trout and larval salamanders (Ambystoma Ambystoma macrodactylummacrodactylum) in high-elevation lakes. Conservation ) in high-elevation lakes. Conservation Biology, 12: 94-105.Biology, 12: 94-105.
Van Buskirk, J. and D.C. Smith. 1991. Density-dependent Van Buskirk, J. and D.C. Smith. 1991. Density-dependent population regulation in a salamander. Ecology, 72: 1747-population regulation in a salamander. Ecology, 72: 1747-1756.1756.
Yurewicz, K. 2004. A growth/mortality trade-off in larval Yurewicz, K. 2004. A growth/mortality trade-off in larval salamanders and the coexistence of intraguild predators salamanders and the coexistence of intraguild predators and prey. Oecologia, 138: 102-111. and prey. Oecologia, 138: 102-111.