Utilization of different prey type patches in the Ural owl(Strix uralensis): a sit-and-wait predator

The predatory behaviour of two species of juvenile wolffish (Anarhichas lupus and Anarhichas minor) was studied during a field campaign across a frontal area off western Greenland. The study focused on ontogenetic changes in prey-type and -size preference of the wolffish and their predatory impact on a cohabiting population of larval sand lance (Ammodytes sp.). Sampling took place along a cross-shelf transect at latitude 66°20' N, and the analysis is based on stomach contents of assembled wolffish (25 cm in length) and abundance estimates of plankton and fish. An ontogenetic change in wolffish prey preference was evident as a dietary shift from copepods and smaller amphipods to larger amphipods and fish larvae. The inclusion of fish larvae in the wolffish diet led to a marked increase in prey biomass, and fish larvae constituted up to 77% of diet biomass in the largest juveniles caught. Wolffish selectively targeted the smaller-sized part of the larval sand lance population; hence, larval vulnerability increased with decreasing size. Comparison between estimated predation rates and abundances of predator and prey indicated larval predation mortalities of up to 5% per day, with mortality peaking in the vicinity of a hydrographic front. Hence, findings suggest substantial predation pressure on larvae, primarily related to larval size and distribution.

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DETECTION OF FOCI OF TULAREMIA USING ENZYME IMMUNOASSAY FOR THE PREDATORY BIRD PELLETS

Periódico Tchê Química ◽

10.52571/ptq.v16.n31.2020.639_periodico31_pgs_632_641.pdf ◽

2019 ◽

Vol 16 (31) ◽

pp. 632-641

Author(s):

Alexey; ANDREYCHEV ◽

Ekaterina BOYAROVA ◽

Alexander LAPSHIN ◽

Vyacheslav KUZNETSOV

Keyword(s):

Enzyme Immunoassay ◽

Causative Agent ◽

Average Content ◽

Predatory Bird ◽

Eagle Owl ◽

The Republic ◽

Ural Owl

The results of identifying tularemia foci using the predatory bird pellets in the central part of Russia using the example of the Republic of Mordovia are presented. The efficacy of tularemia detection in pellets compared with other biomaterials has been shown. The average content of the tularemia microbe antigen from the predatory bird pellets was 9,4%. The greatest number of registrations of the causative agent of tularemia in the pellets was observed in Eagle Owl (29,2%). To a lesser extent, the pathogen was detected in the Ural Owl (14,7%). The tularemia pathogen was detected more often in the bird predator pellets than in the biomaterial from rodents. The largest share of positive samples was recorded in the riverine districts. The dynamics of identifying the causative agent of tularemia should be noted in 2015, 2017 and 2018, which are characterized by high values of the indicator.

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Prey type and foraging ecology of SanderlingsCalidris albain different climate zones: are tropical areas more favourable than temperate sites?

PeerJ ◽

10.7717/peerj.1125 ◽

2015 ◽

Vol 3 ◽

pp. e1125 ◽

Cited By ~ 6

Author(s):

Kirsten Grond ◽

Yaa Ntiamoa-Baidu ◽

Theunis Piersma ◽

Jeroen Reneerkens

Keyword(s):

Foraging Ecology ◽

Prey Type ◽

Climate Zones ◽

Tropical Areas

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Feeding Ecology of Short-Toed Snake-Eagle (Circaetus gallicus [Gmelin, 1788]) in the Montados of Iberian Peninsula

Silva Lusitana ◽

10.1051/silu/20202802139 ◽

2020 ◽

Vol 28 (2) ◽

pp. 155-179

Author(s):

Nuno Onofre ◽

Luís Sampaio

Keyword(s):

Relative Abundance ◽

Diet Composition ◽

Prey Species ◽

Prey Selection ◽

Prey Type ◽

Generalist Predator ◽

Important Prey ◽

Psammodromus Algirus ◽

Circaetus Gallicus ◽

Water Snakes

The diet of Short-toed Snake-eagle (Circaetus gallicus) during the breeding season in an area dominated by cork and holm oak parkland forests (Montados) was analyzed in this study. As expected, results showed that snakes are the dominant prey in the diet of this eagle, comprising up to 92.5% of the identified items, if potential secondary prey species were excluded. The Montpellier Snake (Malpolon monspessulanus) was the most consumed one (42.2%), followed by the Ladder Snake (Zamenis scalaris) (28.0%), and the water snakes (Natrix spp.) (14.2%). According to the same criteria, lizards (mainly Psammodromus algirus) and mammals represent between 4.8 and 2.2%, respectively. Other animals such as pond turtle and amphibians are irregular prey (<1%), and no bird remains were found at all. Short-toed Snake-eagle is usually referred as a stenophagic predator where snakes are by far its most important prey type, and where within this taxonomic group it behaves as a generalist predator. In this study this premise was then tested comparing the relative abundance of the snake species with their proportion in the diet composition of the eagle in order to know whether or not prey selection exists with regard to the species of snakes in this region. Results point to a quite plausible "preference" for the Ladder Snake and an "avoidance" for the smooth snakes group (Macroprotodon brevis/Coronella girondica), and possibly for the Horseshoe Whip (Hemorrhois hippocrepis). The avoidance to the Horseshoe Whip must be indirect and habitat related, while in relation to the two smooth snakes it may be due in large extend to its small size, in particular.

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Evolutionary diversification of tiny ocean predators

10.1101/2020.10.09.333062 ◽

2020 ◽

Author(s):

Francisco Latorre ◽

Ina M. Deutschmann ◽

Aurelie Labarre ◽

Aleix Obiol ◽

Anders Krabberød ◽

...

Keyword(s):

Single Cells ◽

Prey Type ◽

Distribution Patterns ◽

Trophic Levels ◽

Glycoside Hydrolases ◽

Global Ocean ◽

Heterotrophic Flagellates ◽

Evolutionary Diversification ◽

Niche Adaptation ◽

Different Temperatures

ABSTRACTUnicellular eukaryotic predators have a crucial role in the functioning of the ocean ecosystem by recycling nutrients and energy that are channeled to upper trophic levels. Traditionally, these evolutionary-diverse organisms have been combined into a single functional group (Heterotrophic flagellates), overlooking their organismal differences. Here we investigate four evolutionary related species belonging to one cosmopolitan family of uncultured marine picoeukaryotic predators: MAST-4 (species A, B, C, and E). Co-occurrence and distribution analyses in the global surface ocean indicated contrasting patterns in MAST-4A & C, suggesting adaptation to different temperatures. We then investigated whether these spatial distribution patterns were mirrored by MAST-4 genomic content using Single-Cell Genomics. Analyses of 69 single-cells recovered 66-83% of the MAST-4A/B/C/E genomes, which displayed substantial inter-species divergence. MAST-4 genomes were similar in terms of broad gene functional categories, but they differed in enzymes of ecological relevance, such as glycoside hydrolases (GHs), which are part of the food degradation machinery in MAST-4. Interestingly, MAST-4 species featuring a similar GH composition co-excluded each other (A & C) in the surface global ocean, while species with a different set of GHs appeared to be able to co-exist (species B & C) suggesting further niche diversification associated to prey digestion. We propose that differential niche adaptation to temperature and prey type has promoted adaptive evolutionary diversification in MAST-4. Altogether, we show that minute ocean predators from the same family may have different biogeography and genomic content, which need to be accounted to better comprehend marine food webs.

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