scholarly journals Predator size and prey size-gut capacity ratios determine kill frequency and carcass production in terrestrial carnivorous mammals

Oikos ◽  
2018 ◽  
Vol 128 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Annelies De Cuyper ◽  
Marcus Clauss ◽  
Chris Carbone ◽  
Daryl Codron ◽  
An Cools ◽  
...  
Keyword(s):  

1996 ◽  
Vol 47 (6) ◽  
pp. 801 ◽  
Author(s):  
EE Di Giacomo ◽  
MR Perier

Morphology of the main digestive features of cockfish, Callorhinchus callorhynchus, is described and linked to feeding habits. Composition of the diet and size-selective foraging of this species on scallops was studied in northern Patagonian waters and analysed in relation to depth, sex and size. Three species of bivalve molluscs (Pitar rostratus, Aequipecten tehuelchus and Ennucula puelcha) and flabelligerid polychaetes were predominant in the diet of males. The scallop Zygochlamys patagonica dominated the diet of females. The diet of juveniles consisted of small gastropods (Olivella sp.), bivalves with fragile shells (e.g. Pandora cistula), amphipods and polychaetes. Differences in food composition between sexes and between juveniles and adults are attributed to two factors: extrinsic (concerning prey availability) and intrinsic (concerning the morphology and behaviour of the predator). Size-selective foraging on two species of scallops, Aequipecten tehuelchus (subject to commercial fishing) and Zygochlamys patagonica, was found in adults; it is argued that maximum scallop prey size is constrained by the strength of the crushing apparatus of the cockfish. The diet of the cockfish is compared with that of other holocephalans. It is concluded that species of Callorhinchus can be generally characterized as benthic foragers that specialize in crushing shelled invertebrate prey.





2003 ◽  
Vol 81 (2) ◽  
pp. 228-236 ◽  
Author(s):  
Luca Luiselli

Two species of rain-forest snakes, the colubrids Natriciteres fuliginoides and Natriciteres variegata, are potential competitors, because they attain, on average, the same body size (20–30 cm long), have similar habits and ecological requirements (they are both diurnal and nocturnal, often semi-aquatic), and have similar dietary spectra ( including both small vertebrates and invertebrates). I studied prey type and predator size – prey size relationships of these snakes in four swamp-forest areas of southeastern Nigeria (West Africa): only N. fuliginoides was found in two of these areas, whereas both species were common in the other two areas. The feeding ecology of N. fuliginoides shifted greatly in the presence of its potential competitor, N. variegata, in terms of prey-type preferences and predatory behaviour as well as in terms of predator size – prey size relationships. In particular, the effects of the potential competitor on the feeding ecology of N. fuliginoides were (i) a shift toward eating many invertebrates from a diet based on many small vertebrates, (ii) a shift toward eating many terrestrial organisms from a diet based on many aquatic organisms, and (iii) a shift in mean prey size for females toward relatively larger prey from a diet based on smaller prey. The resulting effect was a clear partitioning of food resources between the two predator species in both the areas where they are sympatric, whereas N. fuliginoides had a wider dietary spectrum (covering that of the two species together) in the areas where its competitor is not found. The role of intraspecific competition seems less strong, as no apparent resource partitioning in prey type or prey size was observed between males and females of either species or in any study area. However, mean prey size was significantly greater for females than for males of both species and in all study areas, but depended on the significant reverse sexual size dimorphism observed in both species.



Ecology ◽  
2009 ◽  
Vol 90 (7) ◽  
pp. 2014-2019 ◽  
Author(s):  
Gabriel C. Costa


Ecology ◽  
1990 ◽  
Vol 71 (2) ◽  
pp. 759-775 ◽  
Author(s):  
A. Richard Palmer
Keyword(s):  


2016 ◽  
Vol 283 (1824) ◽  
pp. 20152129 ◽  
Author(s):  
Carmen García-Comas ◽  
Akash R. Sastri ◽  
Lin Ye ◽  
Chun-Yi Chang ◽  
Fan-Sian Lin ◽  
...  

Body size exerts multiple effects on plankton food-web interactions. However, the influence of size structure on trophic transfer remains poorly quantified in the field. Here, we examine how the size diversity of prey (nano-microplankton) and predators (mesozooplankton) influence trophic transfer efficiency (using biomass ratio as a proxy) in natural marine ecosystems. Our results support previous studies on single trophic levels: transfer efficiency decreases with increasing prey size diversity and is enhanced with greater predator size diversity. We further show that communities with low nano-microplankton size diversity and high mesozooplankton size diversity tend to occur in warmer environments with low nutrient concentrations, thus promoting trophic transfer to higher trophic levels in those conditions. Moreover, we reveal an interactive effect of predator and prey size diversities: the positive effect of predator size diversity becomes influential when prey size diversity is high. Mechanistically, the negative effect of prey size diversity on trophic transfer may be explained by unicellular size-based metabolic constraints as well as trade-offs between growth and predation avoidance with size, whereas increasing predator size diversity may enhance diet niche partitioning and thus promote trophic transfer. These findings provide insights into size-based theories of ecosystem functioning, with implications for ecosystem predictive models.



1991 ◽  
Vol 48 (5) ◽  
pp. 933-937 ◽  
Author(s):  
Jean Beyer Rogers ◽  
Craig C. Burley

Laboratory experiments were conducted to examine the effects of water temperature, predator size, prey size, and prey number on gastric evacuation of smallmouth bass (Micropterus dolomieui) fed juvenile salmon. The smallmouth bass were allowed to feed voluntarily after 24–48 h of starvation and stomachs were pumped at intervals of 1–4 h until 90% of the stomach contents were evacuated (E90). Evacuation approximated an S-shaped curve over time, and a sigmoid model was developed to predict evacuation at varying water temperatures, total meal weights, predator sizes, and prey number. The rate of evacuation increased with increasing water temperature, meal weight, or predator size. The E90 increased with larger meal weights but decreased with increasing temperature or predator size. E90 ranged between 4 and 95 h, depending upon conditions. E90 was slower than those estimated previously for another predator of salmon, the stomachless northern squawfish (Ptychocheilus oregonensis).



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