Search results for " behavior"
showing 10 items of 11374 documents
Temporal resolution and temporal transfer properties: gabaergic and cholinergic mechanisms.
2007
Temporal resolution is a basic property of the visual system and critically depends upon retinal temporal coding properties which are also of importance for directional coding. Whether the temporal coding properties for directional coding derive form inherent properties or critically depend upon the temporal coding mechanisms is unclear. Here, the influence of acetylcholine and GABA upon photopic temporal coding was investigated in goldfish, using flicker stimuli, in a behavioral and an electrophysiological (ERG) approach. The goldfish temporal resolution ability decreased from more than 90% correct choices at 20 Hz flicker frequency to about 65% at 45 Hz flicker frequency with a flicker fu…
Impaired crypsis of fish infected with a trophically transmitted parasite
2005
Trophically transmitted parasites may enhance their transmission by altering the phenotype of infected hosts to increase their vulnerability to predation by the next hosts in the life cycle. In an experimental study, we investigated whether the parasite Diplostomum spathaceum (Trematoda) alters cryptic coloration and cryptic behaviour of infected rainbow trout, Oncorhynchus mykiss, so that they would be more conspicuous to avian predators. The parasite reduces the vision of fish by lodging in the eyes and inducing cataract formation, which gives it an opportunity to affect fish crypsis. We examined the effect of the parasite on the ability of fish to adjust their coloration to the environme…
Coloration reflects behavioural types in the convict cichlid, Amatitlania siquia.
2015
9 pages; International audience; Interindividual behavioural differences, consistent over time and across situations, are frequently related to differences in reproductive success, susceptibility to disease and competitive ability. The behavioural phenotype of a conspecific is likely to affect the outcome of a social interaction, so an individual must be able to accurately assess behavioural phenotypes in order to optimize behavioural responses during mate choice, cooperative relationships and agonistic interactions. However, behavioural assessment based on dyadic interactions in different contexts can be costly because it may require significant time, increase the risk of predation and oft…
Stepping up to genome scan allows stock differentiation in the worldwide distributed blue shark Prionace glauca
2023
The blue shark Prionace glauca is a top predator with one of the widest geographic distributions of any shark species, yet classified as critically endangered in the Mediterranean Sea, and Near Threatened globally. Previous genetic studies did not reject the null hypothesis of a single global population across the worldwide species range. Blue shark situation was proposed as a possible archetype of the ‘grey zone of population differentiation’, coined to designate cases where population structure may be too recent or too faint to be detected using a limited set of markers. Here, blue shark samples collected throughout its global range were sequenced using a specific ddRAD method (DArTseq; G…
Climate signatures on decadal to interdecadal time scales as obtained from mollusk shells (Arctica islandica) from Iceland
2013
Abstract Pronounced decadal climate oscillations are detected in a multi-centennial record based on shell growth rates of the marine bivalve mollusk, Arctica islandica, from Iceland. The corresponding analysis of patterns in sea level pressure and temperature exhibit large-scale teleconnections with North Atlantic climate quantities. We find that the record projects onto blocking situations in the northern North Atlantic. The associated circulation shows a low-pressure signature over Greenland and the Labrador Sea and a high-pressure system over Western Europe associated with northeasterly flow towards Iceland and weakening in the westerly zonal flow over Europe. It can be speculated that s…
Studies on the effects of Ca2++ and Co++ on the swimming behavior of the blind Mexican cave fish
1992
The hypothesis that the blind cave fish (Astyanax hubbsi) adjusts the level of stimulation to its lateral line system (LLS) by varying its own velocity was examined. When the sensitivity of the LLS sense organs was reduced by lowering the Ca2+ concentration in the water or by adding Co2+ the fish compensated for this by swimming at a higher velocity.
Allium aetnense (Amaryllidaceae), a new species from Sicily.
2013
A new species from Mt Etna (Sicily), Allium aetenense of A. sect. Codonoprasum, is described and illustrated. It is a diploid species (2n = 16) that grows on basaltic rocks in the mountain belt and shows close relationships with A. tenuiflorum of the Italian peninsula. Its morphology, karyology, leaf anatomy, seed coat microsculpturing, ecology and taxonomic position are examined.
On the discrimination of spatial intervals by the blind cave fish (Anoptichthys jordani).
1986
The performance of the blind cave fish in discriminating spatial intervals was investigated. The fish had to discriminate between pairs of grids consisting of equidistant vertical bars. The intervals between the bars on the grid to be chosen were kept constant while the intervals between the bars on the other grid were altered in steps so as to become gradually closer to the interval between the bars on the grid to be chosen. It was found that the fish were still able to discriminate between the two grids when the difference between the bar intervals amounted to at least 1.5 mm. In interpreting the results it was concluded that the phase information in the stimulus on the skin of the fish m…
Learning and remembering the environment in the blind cave fishAnoptichthys jordani
1989
1. The swimming behavior of blind cave fish (Anoptichthys jordani) differs in familiar and unfamiliar surroundings. Following release in unfamiliar surroundings, or after alterations of a familiar environment, the fish increase swimming velocity in order to optimize lateral line organ stimulation. Furthermore, they glide along boundary features more often than they do in familiar surroundings. These characteristics of swimming behavior were used to measure the occurrence and duration of exploratory behavior. 2. Fish removed from a familiar environment for as long as 2 days spend less time exploring when returned than when they were initially placed in the environment. After a longer absence…
Detection of stationary objects by the blind Cave FishAnoptichthys jordani (Characidae)
1981
It was noticed that the blind Mexican Cave Fish repeatedly passes along objects new to it at a short distance. Observations and experiments are reported which support the hypothesis that water movements occurring between the stationary object and the fish as it passes by convey information about the location and possibly the shape of the object, which is detected by the lateral line organ of the fish. Water movements of the expected type were recorded with the help of a model fish equipped with a mechano-electric analogue of a free neuromast.