scholarly journals Time-dependent latent inhibition of predator-recognition learning

2019 ◽  
Vol 15 (5) ◽  
pp. 20190183 ◽  
Author(s):  
Adam L. Crane ◽  
Douglas P. Chivers ◽  
Maud C. O. Ferrari
Keyword(s):  
Predation Risk ◽  
Latent Inhibition ◽  
Learning Opportunities ◽  
Predator Recognition ◽  
Wood Frog ◽  
Time Dependent ◽  
Negative Consequences ◽  
Lithobates Sylvaticus ◽  
Frog Tadpoles ◽  
Recognition Learning

To optimally manage an environment with predators, prey must correctly distinguish between cues that are risky and cues that are safe. Even a specific cue that is safe in one area or at a certain time may be dangerous in other situations, and vice versa. Latent inhibition is a cognitive mechanism by which animals fail to learn that a stimulus as risky because they have already learned it as non-threatening via previous encounters with the stimulus in the absence of negative consequences. Here, we demonstrate that latent inhibition of predator-recognition learning in wood frog tadpoles, Lithobates sylvaticus , depends on the timing of their learning opportunities. For 6 days, tadpoles were exposed daily to an initially novel stimulus (salamander odour), either in the morning (11.00–13.00 h) or evening (16.00–18.00 h). The following day, we conditioned tadpoles to recognize the salamander odour as a predator by pairing it with injured tadpole cues, either at the same time as their previous experience or at the opposite time. When tested the following day, latent inhibition occurred under each scenario where the timing of conditioning matched the timing of the pre-exposure. However, tadpoles tested in the morning showed learned fright responses when conditioned in the morning if their pre-exposure had occurred in the evening, whereas individuals tested in the evening showed learned fright responses when conditioned in the evening if their pre-exposure had occurred in the morning. This is the first report of time-dependent latent inhibition of predator-recognition learning, which is likely an important mechanism for correctly managing predation risk and safety.

Influence of prey diet quality on predator-induced traits in wood frog tadpoles (Lithobates sylvaticus)

2021 ◽  
pp. 1-11
Author(s):  
Catherine Chuirazzi ◽  
Melissa Ocampo ◽  
Mizuki K. Takahashi
Keyword(s):  
Predation Risk ◽  
Diet Quality ◽  
Growth And Development ◽  
Chemical Cues ◽  
Wood Frog ◽  
Experimental Conditions ◽  
Lithobates Sylvaticus ◽  
Phenotypic Changes ◽  
Intestinal Length ◽  
Frog Tadpoles

Abstract Diet quality and predation are two critical factors in determining the growth and development of organisms. Various anurans are susceptible to phenotypic changes influenced by these factors. Yet, few studies examined prey diet quality as potential influence over predator-induced traits. Using wood frog tadpoles (Lithobates sylvaticus) as a model species, we investigated the effects of three diet compositions (plant-based, animal-based, omnivorous) crossed with presence or absence of chemical cues from predatory dragonfly larvae (Aeshnidae). After 35 days, we recorded 11 morphological measurements, Gosner stage, and intestinal length of tadpoles to assess phenotypic changes under the six different experimental conditions. Our results showed the additive effects of both diet quality and predator chemical cue without detection of interactions between the two. Tadpoles receiving the omnivorous diet grew and developed faster with wider denticle rows than those receiving the plant or animal diets. The growth and development of tadpoles receiving only the animal diet were significantly hindered. These results emphasize the importance of diet quality in the growth and development of larval wood frogs. Chemical cues from predators significantly reduced tadpole body size but, in contrast to previous findings, did not affect tail size. Our experimental procedure of providing water containing predator and injured conspecific chemical cues on a weekly basis likely provided relatively weak predation risk perceived by tadpoles compared to previous studies using caged predators. The predator environment in our experiment, however, represents one ecologically relevant scenario in which predation risk is not urgent.

Carryover effects of phenotypic plasticity: embryonic environment and larval response to predation risk in Wood Frogs (Lithobates sylvaticus) and Northern Leopard Frogs (Lithobates pipiens)

2015 ◽  
Vol 93 (11) ◽  
pp. 867-877 ◽  
Author(s):  
A.M. Bennett ◽  
D.L. Murray
Keyword(s):  
Predation Risk ◽  
Wood Frog ◽  
Leopard Frog ◽  
Carryover Effects ◽  
Wood Frogs ◽  
Lithobates Sylvaticus ◽  
Northern Leopard Frog ◽  
Leopard Frogs ◽  
Frog Tadpoles ◽  
Northern Leopard Frogs

Limitations of phenotypic plasticity affect the success of individuals and populations in changing environments. We assessed the plasticity-history limitation on predator-induced defenses in anurans (Wood Frogs, Lithobates sylvaticus (LeConte, 1825), and Northern Leopard Frogs, Lithobates pipiens (Schreber, 1782)), predicting that plastic responses to predation risk by dragonfly larvae (family Aeshnidae) in the embryonic environment would limit the defensive response to predators in the larval environment. Predator-conditioned Wood Frog embryos increased relative tail depth in response to those same cues as larvae, whereas predator-naive tadpoles did not. However, no carryover effect was noted in the behavioural response of Wood Frog tadpoles to predation risk. Predator-naive Northern Leopard Frog tadpoles increased relative tail depth in response to predation risk in the larval environment. Predator-conditioned Northern Leopard Frog embryos hatched with, and maintained, a marginal increase in tail depth as larvae in the absence of predation risk. Predator-conditioned Northern Leopard Frog embryos exposed to predation risk as larvae showed no morphological response. While we find no strong support for the plasticity-history limitation per se, carryover effects across embryonic and larval life-history stages were noted in both Wood Frog and Northern Leopard Frog, suggesting that predation risk early in ontogeny can influence the outcome of future interactions with predators.

scholarly journals Latent inhibition of predator recognition by embryonic amphibians

2008 ◽  
Vol 5 (2) ◽  
pp. 160-162 ◽  
Author(s):  
Maud C.O Ferrari ◽  
Douglas P Chivers
Keyword(s):  
Latent Inhibition ◽  
Predator Recognition ◽  
Wood Frog ◽  
Tiger Salamander ◽  
Water Control ◽  
Amphibian Embryos ◽  
Reliable Mechanism ◽  
Conspecific Cues

To avoid being captured, prey animals need to be able to distinguish predators from non-predators. Recent studies have shown that amphibians can learn to recognize their future predators while in the egg. Here, we investigated whether amphibians would similarly be able to learn to recognize non-predators while in the egg. We exposed newly laid wood frog eggs to the odour of tiger salamander or a water control daily for 5 days. After hatching, the wood frog larvae were raised for two weeks at which time we tried to condition them to recognize the salamander as a predator. Larvae were exposed to injured conspecific cues paired with salamander odour, a well-established mode of learning for aquatic prey. When subsequently tested for their response to salamander odour, the larvae pre-exposed to water as embryos showed significant anti-predator responses. However, larvae pre-exposed to the salamander odour as embryos showed no learning of the predator, indicating that they had already learned to recognize the salamander as a non-predator. These results indicate that amphibian embryos can (i) learn to recognize stimuli as non-threatening and (ii) remember it for at least two weeks. The widespread ability of prey to learn to recognize non-predators might explain the persistence of injured conspecific cues as a reliable mechanism for learned predator recognition.

Stocked trout do not significantly affect wood frog populations in boreal foothills lakes

2011 ◽  
Vol 68 (10) ◽  
pp. 1790-1801 ◽  
Author(s):  
C.M.M. Schank ◽  
C.A. Paszkowski ◽  
W.M. Tonn ◽  
G.J. Scrimgeour
Keyword(s):  
Trophic Status ◽  
Larval Period ◽  
Wood Frog ◽  
Native Fish ◽  
Negative Consequences ◽  
Lithobates Sylvaticus ◽  
Forage Fishes ◽  
Lake Trophic Status ◽  
Native Populations ◽  
Littoral Habitats

Stocking salmonids into lakes can have negative consequences for some ecosystem components, including amphibians. In the boreal foothills of Alberta, Canada, we compared populations of wood frog ( Lithobates sylvaticus ) at lakes with (n = 5) and without (n = 6) stocked trout over 3 years; all 11 lakes also supported native populations of forage fishes. Abundance and size of adult and young-of-year (YOY) frogs did not differ significantly between stocked and unstocked lakes. We also compared the wood frog population from a twelfth, fishless lake with populations from the 11 fish-bearing lakes (with or without trout); abundance and size of adults and YOY were greater, and YOY emerged earlier in the absence of fish. Based on patterns compiled from a literature review of effects of stocked trout on anuran amphibians, we suggest that characteristics of our study systems, including the presence of native fish, the length of the anuran larval period, lake trophic status, and the existence of complex, littoral habitats, contributed to the lack of major impacts of stocked trout on wood frog populations.

Frugal cannibals: how consuming conspecific tissues can provide conditional benefits to wood frog tadpoles (Lithobates sylvaticus)

2014 ◽  
Vol 101 (4) ◽  
pp. 291-303 ◽  
Author(s):  
Dale M. Jefferson ◽  
Keith A. Hobson ◽  
Brandon S. Demuth ◽  
Maud C. O. Ferrari ◽  
Douglas P. Chivers
Keyword(s):  
Wood Frog ◽  
Lithobates Sylvaticus ◽  
Frog Tadpoles

scholarly journals Time to feed: How diet, competition, and experience may influence feeding behaviour and cannibalism in wood frog tadpoles Lithobates sylvaticus

2014 ◽  
Vol 60 (5) ◽  
pp. 571-580 ◽  
Author(s):  
Dale M. Jefferson ◽  
Keith A. Hobson ◽  
Douglas P. Chivers
Keyword(s):  
Feeding Behaviour ◽  
Chemical Cues ◽  
Response Times ◽  
Wood Frog ◽  
Temporary Wetlands ◽  
Lithobates Sylvaticus ◽  
Chemical Alarm Cues ◽  
Frog Tadpoles ◽  
Cannibalistic Behaviour ◽  
Altered Response

Abstract Wood frog Lithobates sylvaticus tadpoles develop in temporary wetlands where high population densities can force tadpoles into aggregations that intensify competition and can lead to cannibalism. However, chemical alarm cues released from injured conspecifics could also dissuade cannibalism. The purpose of this study was to test mechanisms that may influence cannibalistic behaviour. We tested whether the tendency of tadpoles to consume conspecifics would increase with the presence of competition and/or cues of profitable diets. Tadpoles placed in 1L experimental containers were tested for feeding initiation times of multiple diets, including conspecific tissues and conspecific tissues combined with chemical cues from the alternative diets (brine shrimp and cornmeal). Tadpoles were tested in the presence and absence of a competitor, and at multiple times over the course of the study. Tadpoles exhibited an altered response to diets over time; however the presence of a competitor reduced response times to all diets including conspecific tissues. Similarly, the presence of specific diets also reduced the response time of tadpoles to conspecific tissues. These results suggest competition among feeding tadpoles could result in aggressive behaviour leading to indiscriminate predation and cannibalism.

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