scholarly journals Behavioral signature of intraspecific competition and density dependence in colony‐breeding marine predators

2013 ◽  
Vol 3 (11) ◽  
pp. 3838-3854 ◽  
Author(s):  
Greg A. Breed ◽  
W. Don Bowen ◽  
Marty L. Leonard
Keyword(s):  
Density Dependence ◽  
Intraspecific Competition ◽  
Marine Predators ◽  
Behavioral Signature

Density dependence of feeding success in haematophagous ectoparasites

Parasitology ◽  
2007 ◽  
Vol 134 (10) ◽  
pp. 1379-1386 ◽  
Author(s):  
B. R. KRASNOV ◽  
A. HOVHANYAN ◽  
I. S. KHOKHLOVA ◽  
A. A. DEGEN
Keyword(s):  
Density Dependence ◽  
Intraspecific Competition ◽  
Interference Competition ◽  
Host Defence ◽  
Defence System ◽  
Feeding Success ◽  
Alternative Hypotheses ◽  
Mean Size ◽  
The Mean ◽  
Host Defence System

SUMMARYWe studied the effect of density on feeding success of 2 fleas, Xenopsylla conformis and Xenopsylla ramesis, when exploiting rodents Meriones crassus and Gerbillus dasyurus. We tested 2 alternative hypotheses: (i) that intraspecific interference competition occurs and, thus, feeding success of a flea decreases with an increase in density and (ii) that facilitation via suppression of a host defence system occurs and thus, feeding success of a flea increases with an increase in density. The mean size of a bloodmeal and the proportion of highly engorged individuals in X. conformis feeding on both hosts were affected by density. When on G. dasyurus, both the size of a bloodmeal and the proportion of highly engorged individuals were lower at low (5–15 fleas per host) than at high (25–50 fleas per host) densities. The opposite was true when this flea fed on M. crassus. The mean bloodmeal size and proportions of highly engorged X. ramesis parasitizing either host were not affected by flea density. This study showed that the density dependence of feeding success of a flea (a) varied both between fleas and within-fleas between hosts and (b) indicated either intraspecific competition or facilitation via the host in a particular flea-host association.

Population organisation in reef sharks: new variations in coastal habitat use by mobile marine predators

2016 ◽  
Vol 544 ◽  
pp. 197-211 ◽  
Author(s):  
A Chin ◽  
MR Heupel ◽  
CA Simpfendorfer ◽  
AJ Tobin
Keyword(s):  
Habitat Use ◽  
Coastal Habitat ◽  
Marine Predators ◽  
Reef Sharks

Spatiotemporal distribution of foraging in a marine predator: behavioural drivers of hotspot formation

2020 ◽  
Vol 635 ◽  
pp. 187-202
Author(s):  
T Brough ◽  
W Rayment ◽  
E Slooten ◽  
S Dawson
Keyword(s):  
Time Of Day ◽  
Spatiotemporal Distribution ◽  
Temporal Effects ◽  
Marine Predator ◽  
Marine Predators ◽  
Additive Mixed Models ◽  
Density Analysis ◽  
The Times ◽  
Passive Acoustic ◽  
Spatial Locations

Many species of marine predators display defined hotspots in their distribution, although the reasons why this happens are not well understood in some species. Understanding whether hotspots are used for certain behaviours provides insights into the importance of these areas for the predators’ ecology and population viability. In this study, we investigated the spatiotemporal distribution of foraging behaviour in Hector’s dolphin Cephalorhynchus hectori, a small, endangered species from New Zealand. Passive acoustic monitoring of foraging ‘buzzes’ was carried out at 4 hotspots and 6 lower-use, ‘reference areas’, chosen randomly based on a previous density analysis of visual sightings. The distribution of buzzes was modelled among spatial locations and on 3 temporal scales (season, time of day, tidal state) with generalised additive mixed models using 82000 h of monitoring data. Foraging rates were significantly influenced by all 3 temporal effects, with substantial variation in the importance and nature of each effect among locations. The complexity of the temporal effects on foraging is likely due to the patchy nature of prey distributions and shows how foraging is highly variable at fine scales. Foraging rates were highest at the hotspots, suggesting that feeding opportunities shape fine-scale distribution in Hector’s dolphin. Foraging can be disrupted by anthropogenic influences. Thus, information from this study can be used to manage threats to this vital behaviour in the locations and at the times where it is most prevalent.

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