Search results for "zoology"
showing 10 items of 4160 documents
Sex and sexual ornamentation associated with survival of the cyprinid fish, Rutilus rutilus, under disease stress
2013
By conveying information of disease resistance, sexual signals may be used as cues for adaptive mate choice. Here we report observations on survival of laboratory-maintained, wild-collected, sexually mature, ready-to-spawn cyprinid fish, Rutilus rutilus (roach), under accidental epidemic attributed to Flavobacterium psychrophilum, diagnosed using species-specific PCR. The fish were maintained in a single tank. During the 27 days observation period, both the proportion of fish surviving the infection as well as the length-adjusted mean survival time of the fish that died was the highest among the high-ornamented males with large breeding tubercles, intermediary among the low-ornamented males…
Les animaux de la nécropole gallo-romaine de Vertault (Côte d'Or, France)
2007
The skeletons, partial skeletons and isolated bones of 200 dogs, 42 horses, eight sheep and two cattle were recovered at the animal necropolis of Vertault, situated south of the fortifi ed rampart belonging to the Gaulish-Roman village on an incompletely examined stretch of land. Because archaeological fi nds were lacking, three 14C analyses were conducted on horse bone material to provide chronological identifi cation, which dated the faunal remains to the 1st century AD. All of the animals are males. Although the horses are fully mature and some of them very old, the dogs and sheep are all young animals. These animals, some of which show clear evidence on the skull of violent death, were …
First measurements of field metabolic rate in wild juvenile fishes show strong thermal sensitivity but variations between sympatric ecotypes
2021
The relationship between physiology and temperature has a large influence on population-level responses to climate change. In natural settings, direct thermal effects on metabolism may be exaggerated or offset by behavioural responses influencing individual energy balance. Drawing on a newly developed proxy, we provide the first estimates of the thermal performance curve of field metabolism in a wild fish. We investigate the thermal sensitivity of field metabolic rate in two sympatric, genetically distinct ecotypes of Atlantic cod from the Skagerrak coast of southern Norway. The combined ecotype median of field metabolic rate increased with increasing temperature until around 16°C, coincide…
Primer estudio experimental sobre los efectos de la digestión en restos esqueléticos de murciélagos (Mammalia: Chiroptera)
2018
Taphonomic studies dealing with small mammals do not usually consider bats. Therefore, the degree to which bat bones are modi? ed by predation and other taphonomic agents are largely unknown. Here we present the results obtained from a set of experiments developed to approach this issue, focusing initially on the e?ect of digestion. For this purpose several bat bones and teeth were exposed to HCl and to two di?erent proteolithic enzymes. The experiments showed that bat bones are altered by acidic and enzymatic attack in a similar way as the bones of other small mammals. However, some patterns were observed in the teeth that had not been previously described in other groups. Thus, both the i…
Enameloid microstructure in the oldest known chondrichthyan teeth
2009
Botella, H., Donoghue, P.C.J and Martinez-Perez, C. 2009. The enameloid microstructure of the oldest known chondrichthyan teeth. — Acta Zoologica (Stockholm) 90 (Suppl. 1): 103‐108 Previous studies on tooth enameloid microstructure in several chondrichthyan taxa spanning the phylogeny of the group provided support for the homology of chondrichthyan tooth enameloid. This hypothesis requires that a single crystallite enameloid (SCE) monolayer must be present in the teeth of the most primitive chondrichthyan. However, the dental microstructure of the earliest sharks has yet to be investigated. We have studied the tooth enameloid microstructure of the two oldest tooth-bearing shark species curr…
Tryptophan metabolic pathways and brain serotonergic activity: A comparative review
2019
The essential amino acid L-tryptophan (Trp) is the precursor of the monoaminergic neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). Numerous studies have shown that elevated dietary Trp has a suppressive effect on aggressive behavior and post-stress plasma cortisol concentrations in vertebrates, including teleosts. These effects are believed to be mediated by the brain serotonergic system, even though all mechanisms involved are not well understood. The rate of 5-HT biosynthesis is limited by Trp availability, but only in neurons of the hindbrain raphe area predominantly expressing the isoform TPH2 of the enzyme tryptophan hydroxylase (TPH). In the periphery as well as in brain areas …
Parasite avoidance behaviours in aquatic environments
2018
Parasites, including macroparasites, protists, fungi, bacteria and viruses, can impose a heavy burden upon host animals. However, hosts are not without defences. One aspect of host defence, behavioural avoidance, has been studied in the terrestrial realm for over 50 years, but was first reported from the aquatic environment approximately 20 years ago. Evidence has mounted on the importance of parasite avoidance behaviours and it is increasingly apparent that there are core similarities in the function and benefit of this defence mechanism between terrestrial and aquatic systems. However, there are also stark differences driven by the unique biotic and abiotic characteristics of terrestrial …
Comparative transcriptomics of albino and warningly‐coloured caterpillars
2021
Abstract Coloration is perhaps one of the most prominent adaptations for survival and reproduction of many taxa. Coloration is of particular importance for aposematic species, which rely on their coloring and patterning acting as a warning signal to deter predators. Most research has focused on the evolution of warning coloration by natural selection. However, little information is available for color mutants of aposematic species, particularly at the genomic level. Here, I compare the transcriptomes of albino mutant caterpillars of the aposematic wood tiger moth (Arctia plantaginis) to those of their full sibs having their distinctive orange‐black warning coloration. The results showed >29…
Size-related mortality during overwintering in cavity-nesting ant colonies (Hymenoptera: Formicidae)
2016
The ongoing process of climate change will result in higher temperatures during winter and therefore might increase the survival of overwintering invertebrates. However, the process may also lead to a reduction in snow cover and expose overwintering invertebrates to lower temperatures, which could result in higher mortality. During a field experiment, I investigated the effects of a reduction in snow cover on the survival of the ant Temnothorax crassispinus, which overwinters in nests located on the ground. Ant colonies differed in the survival rate of the workers in the experimental (from which snow cover was removed) and control group. In the control group, the survival rate was unrelated…
Dog-Owner Relationship, Owner Interpretations and Dog Personality Are Connected with the Emotional Reactivity of Dogs
2022
Simple Summary The relationship between owner and the dog affects the dog's attachment behaviors and stress coping. In turn, the quality of the relationship may affect owner's interpretations about their dog's behavior. Here, we assessed dogs' emotional responses from heart rate variability and behavioral changes during five different situations. Dog owners evaluated the emotion (valence and arousal) of their dog after each situation. We found that both negative and positive incidents provoked signs of emotional arousal in dogs. Owners detected the dog's arousal especially during fear- and stress-evoking situations. The dog-owner relationship did not affect owners' interpretation of dogs' e…