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.

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.

The role of latent inhibition in acquired predator recognition by fathead minnows

2006 ◽  
Vol 84 (4) ◽  
pp. 505-509 ◽  
Author(s):  
Maud C.O. Ferrari ◽  
Douglas P. Chivers
Keyword(s):  
Associative Learning ◽  
Latent Inhibition ◽  
Aquatic Organisms ◽  
Predator Recognition ◽  
Skin Extract ◽  
Distilled Water ◽  
Learning Mechanisms ◽  
Predator Prey ◽  
Efficient Learning

The ability of prey animals to recognize and respond to potential predators has important survival consequences. In many predator–prey systems, prey need to learn which species are potential predators. Consequently, selection should favour efficient learning mechanisms. For aquatic organisms, a very effective way to learn to identify potential predators is by associating cues of injured conspecifics with cues of an unknown predator. To our knowledge, no studies of fishes have failed to show successful acquisition of predator recognition using this learning method. The goal of our study was to begin to address the limits of this learning paradigm. Specifically, we tested whether pre-exposure to a novel predator would prevent the associative learning from occurring. In the first treatment, we pre-exposed minnows to distilled water for 1 h on 5 consecutive days and then conditioned them with conspecific skin extract paired with charr odour. In the second treatment, minnows were pre-exposed to charr odour and conditioned with conspecific skin extract paired with charr odour. In the last treatment, minnows were pre-exposed to charr odour but “conditioned” with distilled water paired with charr odour. When tested for recognition of the charr odour alone, only the fish that were not pre-exposed to charr odour showed responses to the predators. We conclude that latent inhibition affects the efficiency of associative learning of the predator.

Commissioning brownstock washing controls for an evaporator limited mill

TAPPI Journal ◽  
2016 ◽  
Vol 15 (7) ◽  
pp. 459-464
Author(s):  
RICARDO SANTOS ◽  
PETER HART
Keyword(s):  
Control System ◽  
Negative Impact ◽  
Black Liquor ◽  
Pulp Mill ◽  
Control Program ◽  
Separation Point ◽  
Water Control ◽  
Oxygen Delignification ◽  
Percentage Points

An automated shower water control system has been implemented to reduce the volume and variability of weak black liquor being sent from the pulp mill to the evaporators. The washing controls attempt to balance the need for consistent and low soda carryover to the bleach plant with consistently high weak black liquor solids being sent to the evaporators. The washer controls were implemented on two bleachable grade hardwood lines (one with oxygen delignification, one without oxygen delignification) and one pine line. Implementation of the control program resulted in an increase in black liquor solids of 0.6 percentage points for the hardwood lines. Significant foam reduction was realized on the pine line since the pine black liquor solids were able to be consistently maintained just below the soap separation point. Low black liquor solids excursions to the evaporators were eliminated. Bleach plant carryover was stabilized and no negative impact on chemical consumption was noticed when controlling weak black liquor solids to recovery.

Sodium silicate-based composition used for water control in producing wells

2020 ◽  
pp. 82-84
Author(s):  
I.G. Fattakhov ◽  
◽  
A.S. Zhirkeev ◽  
A.K. Sakhapova ◽  
R.R. Stepanova ◽  
...  
Keyword(s):  
Sodium Silicate ◽  
Water Control
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