Donnerstag, 22 April 2021 07:23

VENCES, M. & KNIEL, C. (1998)

Mikrophage und myrmecophage Ernährungsspezialisierung bei madagassischen Giftfröschen der Gattung Mantella.

SALAMANDRA, Rheinbach, 34(3): 245-254.

Zusammenfassung:

Eine Analyse des Mageninhalts von 15 Exemplaren (vier Arten) der Gattung Mantella (Anura: Ranidae: Mantellinae) zeigte eine mikrophage und myrmecophage Spezialisierung dieser Frösche. Von 774 identifizierten Beutetieren waren 74% Ameisen, 94% hatten Gesamtlängen von 1-4 mm, und keines war größer als 5 mm. Die Ergebnisse experimenteller Beutewahlversuche waren weniger eindeutig. Im Vergleich zu aposematischen Dendrobatiden (Dendrobates histrionicus, D. leucomelas, Phyllobates bicolor) zeigten Mantella-Arten eine deutlich schwächere Bevorzugung kleiner Beute, obwohl die mittlere Länge der Beutetiere, die von einer zusammengefassten Gruppe aller untersuchten Mantella-Arten gefressen wurden, signifikant geringer als die einer Vergleichsgruppe anderer Anuren der Gattungen Rana, Bufo, Mantidactylus, Colostethus und Heterixalus war. Möglicherweise ist die Mikrophagie von Mantella weniger durch ein eingeschränktes Beutewahlspektrum als durch das tagsüber stattfindende, aktive Umherstreifen bei der Nahrungssuche bedingt. Nach der verfügbaren Literatur sind alle Anuren, die bekanntermaßen Hautalkaloide enthalten, mikrophag; die meisten sind spezialisierte Ameisenfresser. Dies weist darauf hin, dass der Ursprung der Alkaloide bei Froschlurchen generell in einer Aufnahme über Arthropoden-Nahrung (Ameisen), wie sie für Dendrobatiden kürzlich nachgewiesen wurde, liegen könnte.

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Blood Values of Adult Captive Cheetahs (Acinonyx jubatus) Fed Either Supplemented Beef or Whole Rabbit Carcasses.

Zoo Biology 30: 1–13.

This study evaluated nutrient intake and relevant blood parameters of 14 captive cheetahs, randomly assigned to a meat-only diet (supplemented beef, SB) or a whole prey diet (whole rabbit, WR) for 4 weeks each. Despite a higher food intake, daily metabolizable energy intake was lower when fed WR (308 kJBW1) compared with SB (347 kJBW1) (P50.002). The ratio of protein to fat was markedly lower for WR (2.3:1) compared with SB (8.8:1), which was reflected in higher serum urea levels when fed SB (P50.033), and a tendency for elevated cholesterol levels when fed WR (P50.055). Taurine intake of cheetahs fed WR was low (0.06% on DM basis); however, analytical error during taurine analysis cannot be ruled out. Feeding WR resulted in a well-balanced mineral intake, in contrast to SB. The latter provided a low calcium:phosphorus ratio (1:2.3), thereby increasing the risk of metabolic bone disease. The high zinc content of SB (200mg/kg DM), compared with WR (94mg/kg DM), was reflected in higher serum zinc concentrations (P50.011). Feeding WR resulted in an increase in serum vitamin A (P50.011). Therefore, the risk of hypervitaminosis A in captive cheetahs when fed WR exclusively on a long-term basis should be evaluated. Our findings suggest that neither diet is likely to provide appropriate nutrition to captive cheetahs when fed exclusively.

depauw-biblio

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Mittwoch, 10 Februar 2021 09:30

VASEY, N. (2000)

Niche separation in Varecia variegata rubra and Eulemur fulvus albifrons: I. Interspecific patterns.

American Journal of Physical Anthropology 112 (3): 411-431
https://doi.org/10.1002/1096-8644(200007)112:3<411::AID-AJPA10>3.0.CO;2-R

Kurzfassung:

Niche separation was documented in a year‐long study of Varecia variegata rubra and Eulemur fulvus albifrons on the Masoala Peninsula, Madagascar. Feeding trees were measured, and diet, forest height, and forest site were recorded at 5‐min time points on focal animals. For time point data, multivariate and bivariate analysis of frequencies was employed to examine how niche dimensions vary between species according to sex, season, and reproductive stage. V. v. rubra feeds in larger trees than E. f. albifrons. V. v. rubra has a diet consisting mainly of fruit, whereas E. f. albifrons has a more varied diet. V. v. rubra ranges mainly above 15 m in tree crowns, whereas E. f. albifrons ranges mainly below 15 m in a wide array of forest sites. Both species are largely frugivorous, but they harvest fruit in different‐sized trees, in different quantities, and in different forest strata. Niche partitioning varies in tandem with seasonal shifts in climate and food availability and with reproductive stages. Seasonal shifts in forest site and forest height use are largely attributed to species‐specific tactics for behavioral thermoregulation and predator avoidance. The diet of E. f. albifrons is diverse whether examined by season or reproductive stage. However, females of both species diversify their diets with more low‐fiber protein than males during gestation, lactation, and the hot seasons. This pattern is most pronounced for V. v. rubra females and may be directly attributed to high energetic investment in reproduction. These results suggest that niche partitioning may be driven more by the energetic requirements of reproductive females than males.

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Biogeographical and Topographical Variation in the Prey of the Black Eagle in the Cape Province, South Africa.

Ostrich 62: 59-72.

Summary:

Prey remains collected at or near Black Eagle Aquila verreauxii nest sites in the Cape Province, South Africa, were analysed according to frequency of occurrence of prey species in the samples. A total of 5748 prey individuals, collected from 73 sites, was analysed according to three biome groups and four nest site types. The Rock Hyrax Procavia capensis is the dominant prey species, but the eagles' diet spectrum varies according to its availability. Indices of species richness and diversity of the prey are inversely correlated with the proportion of the prey contributed by P. capensis, which in turn is determined by topography and vegetation. Biome has a greater influence on the indices than has nest site type. The age structure of the P. capensis prey remains closely reflects the juvenile:sub-adult:adult ratios in the biomes and at the nest site types. Medium-sized (approx. 1-4,5 kg) prey is usually taken. Juvenile domestic small-stock (lambs and goat kids) comprised only 3,4% of the overall total.

boshoff-biblio

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The food consumption of Southern elephant seals (Mirounga leonina)

Aquatic Mammals 17 (2): 76-87.

Summary:

This study concerns the food consumption of 1 male and 2 female Southern elephant seals at Marineland, Antibes, France. The females' food intake increased for about 3 years after which it stabilized at around 3'400 kg/year. The male's annual intake  reached a peak of 11'600 kg during his 6th year after which it dropped and stabilized at around 8'000 kg/year. Although the animals were allowed to eat as much as they wanted, the food intake fluctuated seasonally. The annual periods with low food intake correspond with the breeding (after maturity) and moulting seasons in both sexes. After each moult, the animals increased their food consumption to replenish their energy reserves. In relation to their body weight, the animals ate less than the rough estimate normally used for animals in the wild. This could be because, at Marineland, the air and water temperatures are higher, the diet has a higher energy contents and less energy is needed for feeding than in the wild.

kastelein-biblio

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Diet of the Chilean Tinamou (Nothoprocta perdicaria) in central-south Chile.

ORNITOLOGIA NEOTROPICAL 17: 467–472.

Kurzmitteilung:

... We analysed the contents of crops and stomachs obtained from 79 birds captured in different agricultural areas, years, and seasons in the Ñuble Province, south central Chile. ... Diet consisted mainly of wild plant seeds. The consumption of animal material was scarce and consisted of one insect and crustacean species. During the summer, the seeds of the Poaceae family were most common ... The Chilean Tinamou in Ñuble appears to be essentially a granivorous species with invertebrates being consumed in a variable proportion depending of the season.

gonzalez-biblio

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On the coral-feeding habit of the sea star Peltaster placenta.

Marine Biodiversity 49: 2009–2012.

Abstract:

The predatory activity of the asteroid Peltaster placenta (Müller and Troschel, 1842) on the black coral Parantipathes larix (Esper, 1790) is here described for the first time based on video footage obtained during a Remotely Operated Underwater Vehicle (ROV) survey conducted in the Pontine Archipelago (Southern Tyrrhenian Sea, Mediterranean Sea). Feeding is carried out on the living coenenchyme of the basal axis and pinnules of the antipatharian and is confirmed by the occurrence of its cnidocysts in the sea star gut content. The chitinous skeletal parts of the black coral are left intact as bare tissue, which helps to relate colonies to the predation event. Among all black coral species present in the research area, P. placenta was observed grazing exclusively on P. larix, similarly to other goniasterids known to be deep-sea corallivores with a marked selectivity for their prey. The predatory behaviour of P. placenta was previously unknown. The extent of its feeding traces suggests a significant influence on benthic trophic relationships and, ultimately, on the functioning, structure and health status of deep Mediterranean black coral forests.

bo-biblio

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Feeding preferences of the dusky grouper (Epinephelus marginatus, Lowe 1834) larvae reared in semi-intensive conditions: A contribution addressing the domestication of this species.

Aquaculture 289 (2009): 289–296.

Abstract:

Despite research efforts addressing artificial propagation, dusky grouper aquaculture still relies onexperimental trials owing to the low survival rates of larvae and juveniles, thus rendering mass rearing difficult to attain. Although some authors suggested that the preys offered to the early larval stages represent the major problem facing the rearing of all grouper species, very little information is available in literature on larval development and the behaviour of dusky grouper. The objective of this study was to investigate the trophic preferences of larval stages of the dusky grouper by rearing using a semi-intensive technology. Larvae were reared in pilot scale mesocosms (60 m3) from 3 to 35 days post hatching. The rearing system was supplied with wild zooplankton collected in a natural coastal lagoon in order to augment the chances of satisfying the larvae's feeding requirements; the feeding preferences were analyzed during ontogenesis. The relationship between mouth gape and dimensions of preys, considered as 3-D objects, was investigated to identify possible critical factor. The results of this study suggested a sequence of suitable food items from the beginning of exogenous feeding until day 35 post hatching. In particular, dusky grouper larvae actively select copepod nauplii in the size range between 2 and 12 mm in TL, and Artemia salina nauplii for TL larger than 9 mm. The rearing approach applied seemed to be promising. Indeed, while previous rearing trials of dusky grouper failed within ten days or finished at 30 days post hatching with a lower percent of survivors, this paper reports the best survival rate reported for this species (10%±7.0 survivors at 35 days post hatching). Finally, mouth width was observed to be the limiting factor in the selection of prey, while the smallest prey size plays a critical role in determining ingestion. Our results contribute to clarifying some aspects of the larval ecology of this species, furnishing some suggestions for its cultivation.

russo-biblio

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Donnerstag, 18 Juni 2020 14:09

GRIMM, R. (1969)

Blauböckchen (Cephalophus monticola [Thunberg,1798]; Cephalophmae, Bovidae) als Insektenfresser.

Zeitschrift für Säugetierkunde 35: 357-359.

Zusammenfassung:

Im Mageninhalt von Blauböckchen (Cephalophus monticola) aus freier Wildbahn stellte der Verfasser eine große Menge angedauter Ameisen der Art Paltothyreus tarsatus fest. Eine quantitative Untersuchung ergab, dass die Ameisen einen Anteil von 11,2% am Trockengewicht des Mageninhalts ausmachten. Da P. tarsatus überwiegend solitär lebt,muss angenommen werden, dass Cephalophus monticola die Ameisen nicht zufällig, sondern bewußt aufnimmt, womit er sich in die Reihe der carnivoren Antilopen einordnet.

grimm-biblio

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Maintenance and breeding of duikers Cephalophus spp. at Gladys Porter Zoo, Brownsville

International Zoo Yearb. 20: 93-98.
https://doi.org/10.1111/j.1748-1090.1980.tb00949.x

Inhalt:

Der Gladys Porter Zoo hielt damals eine der größten Ducker-Kollektionen bestehend aus 30 Tieren in 6 Arten. Es wird über die Haltung und Zucht dieser Tiere berichtet, insbesondere über den erhöhten Kupferbedarf des Zebraduckers.

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