Search results for "102"
showing 10 items of 2892 documents
Jellyfish blooms perception in Mediterranean finfish aquaculture
2017
7 pages, 5 figures, 3 tables, supplemental material https://doi.org/10.1016/j.marpol.2016.11.005
Trophic relationships between two gurnards Trigla lucerna and Aspitrigla obscura from the western Mediterranean
1997
The feeding habits of Trigla lucerna L. (1758) and Aspitrigla obscura L. (1764) (Pisces: Triglidae), off the coast of the Gulf of Valencia (Spain), were investigated between October 1989 and January 1991. The two species examined in this study appear to have distinct feeding types, based on the species composition of prey and the frequency of occurrence of major food items. Tub gurnard had a more diverse diet and fed mainly on crustaceans (mysids and decapods), teleosts and molluscs, whilst long fin gurnard were less piscivorous and fed mainly on mysids and natantids. No significant differences were found in the annual variation of vacuity coefficient for either species. Diet composition in…
Dust and grit matter: abrasives of different size lead to opposing dental microwear textures in experimentally fed sheep (Ovis aries)
2020
ABSTRACT External abrasives ingested along with the herbivore diet are considered main contributors to dental wear, though how the different sizes and concentrations of these abrasives influence wear remains unclear. Dental microwear texture analysis (DMTA) is an established method for dietary reconstruction which describes a tooth9s surface topography on a micrometre scale. The method has yielded conflicting results as to the effect of external abrasives. In the present study, a feeding experiment was performed on sheep (Ovis aries) fed seven diets of different abrasiveness. Our aim was to discern the individual effects of size (4, 50 and 130 µm) and concentration (0%, 4% and 8% of dry mat…
The way wear goes: phytolith-based wear on the dentine–enamel system in guinea pigs (Cavia porcellus)
2019
The effect of phytoliths on tooth wear and function has been contested in studies of animal–plant interactions. For herbivores whose occlusal chewing surface consists of enamel ridges and dentine tissue, the phytoliths might particularly erode the softer dentine, exposing the enamel ridges to different occlusal forces and thus contributing to enamel wear. To test this hypothesis, we fed guinea pigs (Cavia porcellus; n = 36 in six groups) for threeweeks exclusively on dry or fresh forage of low(lucerne), moderate (fresh timothy grass) or very high (bamboo leaves) silica content representing corresponding levels of phytoliths. We quantified the effect of these treatments with measuremen…
Bayesian analysis improves experimental studies about temporal patterning of aggression in fish.
2017
Made available in DSpace on 2018-12-11T17:15:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-12-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This study aims to describe a Bayesian Hierarchical Linear Model (HLM) approach for longitudinal designs in fish's experimental aggressive behavior studies as an alternative to classical methods In particular, we discuss the advantages of Bayesian analysis in dealing with combined variables, non-statistically significant results and required sample size using an experiment of angelfish (Pterophyllum scalare) species as case study. Groups of 3 individuals were subjected to daily observations recorded for 10 min durin…
Changes in spawning-stock structure and recruitment pattern of red mullet, Mullus barbatus, after a trawl ban in the Gulf of Castellammare (central M…
2008
Abstract Fiorentino, F., Badalamenti, F., D’Anna, G., Garofalo, G., Gianguzza, P., Gristina, M., Pipitone, C., Rizzo, P., and Fortibuoni, T. 2008. Changes in spawning-stock structure and recruitment pattern of red mullet, Mullus barbatus, after a trawl ban in the Gulf of Castellammare (central Mediterranean Sea). – ICES Journal of Marine Science, 65: 1175–1183. The increase in biomass of red mullet, Mullus barbatus, in the Gulf of Castellammare (northwestern Sicily, central Mediterranean) after a 14-year trawl ban, prompted us to compare the spawning-stock structure and the recruitment pattern before and after the closure. Datasets obtained from three experimental trawl surveys were availab…
Changing winter conditions in the boreal forest : the effects of fluctuating temperature and predation risk on activity and physiological stress leve…
2016
Due to global climate change, the winter conditions in the North are predicted to change, as the time with an intact insulating snow cover gets shorter or disappears altogether. For small mammals, this could cause exposure to strong temperature fluctuations and increased predation risk, inducing severe stress and leading to alterations in the physical condition and behavior. To test this, we exposed bank voles (Myodes glareolus) to different temperature regimes and cues of predator threat under laboratory conditions. The test animals experienced either a stable but cool temperature regime resembling the stable conditions under snow cover, or an unstable temperature regime with cold nights a…
Male mating success and risk of predation in a wolf spider: a balance between sexual and natural selection?
1998
1. Traits that benefit males through sexual selection are simultaneously expected to impair males by provoking costs through natural selection. If we consider the two male fitness components, mating success and viability, then we may expect that the increase in male mating success resulting from a larger trait size will be counterbalanced by an increase in viability costs. 2. We studied the benefits and costs of male mate searching and sexual signalling activity in the wolf spider Hygrolycosa rubrofasciata. In the field, males search females actively and court them by drumming dry leaves with their abdomen. Females have been shown to prefer males with high drumming rate. Male moving and e…
Colour patch size and measurement error using reflectance spectrophotometry
2017
1 - Over the past twenty years, portable and relatively affordable spectrophotometers have greatly advanced the study of animal coloration. However, the small size of many colour patches poses methodological challenges that have not, to date, been assessed in the literature. Here, we tackle this issue for a reflectance spectrophotometry set-up widely used in ecology and evolution (the beam method). 2 - We reviewed the literature on animal coloration reporting the use of reflectance spectrophotometry to explore how the minimum measurable size of a colour patch is determined. We then used coloured plastic sheets to create artificial colour patches, and quantify the relationship between colour…
Cohabitation of tree holes by ants and breeding birds in a temperate deciduous forest
2015
A previously unknown association of ants with birds breeding in tree holes is described. Ants Lasius brunneus Latreille (Hymenoptera: Formicidae) were found in c. 15% of nests of Parus major L. and Poecile palustris L. (Paridae) breeding in tree holes in the primeval deciduous forest located in the Białowieża National Park (Poland). The ants preferably used holes located higher above the ground. As such holes are warmer than the unused holes or other nest sites, it is suggested that the ants cohabit holes utilized by the tits to gain thermal benefits.