Opportunistic Feeding in Mediterranean Blennioid Fishes (Blenniidae and Tripterygion) as Revealed by Experimental Food Provisioning in the Field

1991 ◽  
Vol 12 (1) ◽  
pp. 63-73 ◽  
Author(s):  
Kurt Kotrschal ◽  
Dave G.Lindquist ◽  
Ingeborg P. Illich
2020 ◽  
Vol 15 (3) ◽  
pp. 237-248
Author(s):  
Valeria Senigaglia ◽  
Lars Bejder

Marine wildlife tourism attractions often use food rewards to ensure close-up encounters with freeranging animals. In Bunbury, Western Australia, the Dolphin Discovery Centre (DDC) conducts a foodprovision program where bottlenose dolphins (N = 22; between 2000 and 2018) are offered food rewards to encourage their visitation at a beach in front of the DDC. We used historical records on individual beach visits by adult female dolphins collected by the DDC from 2000 to 2018 to develop generalized mixed effects models (GLMM) to test whether the frequency of beach visitation was influenced by their reproductive status (pregnant, lactating, nonreproductive) or climatic events (El Niño-Southern Oscillation phases) that could affect prey availability. We also quantified the behavioral budget of dolphins during food-provisioning sessions and documented intra- and interspecific aggressive behaviors using individual focal follows collected in 2017–2018. Provisioned females spend most of the time resting within the interaction area (66.3%) and aggressive interactions arise as a consequence of dominance behavior over food access. Visitation rates were most influenced by reproductive status with pregnant and lactating females visiting the provisioning area more frequently (z = 2.085, p = 0.037 and z = 2.437, p = 0.014, respectively). Females that frequently visit the provisioning area expose their dependent calves to regular human interactions at an early age when they are more susceptible to behavioral conditioning. Such experiences could cause the loss of awareness towards humans and promote maladaptive behaviors such as begging that increase risk of entanglement in fishing gear, boat strikes, and propeller injuries.


2019 ◽  
Vol 26 (3) ◽  
pp. 384-404 ◽  
Author(s):  
Nozomi Kawarazuka ◽  
Catherine Locke ◽  
Janet Seeley

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 432
Author(s):  
Robin Gutting ◽  
Ralf-Uwe Syrbe ◽  
Karsten Grunewald ◽  
Ulf Mehlig ◽  
Véronique Helfer ◽  
...  

Mangrove forests provide a large variety of ecosystem services (ES) to coastal societies. Using a case study focusing on the Ajuruteua peninsula in Northern Brazil and two ES, food provisioning (ES1) and global climate regulation (ES2), this paper proposes a new framework for quantifying and valuing mangrove ES and allow for their small-scale mapping. We modelled and spatialised the two ES from different perspectives, the demand (ES1) and the supply (ES2) side respectively. This was performed by combining worldwide databases related to the global human population (ES1) or mangrove distribution and canopy height (ES2) with locally derived parameters, such as crab catches (ES1) or species-specific allometric equations based on local estimates of tree structural parameters (ES2). Based on this approach, we could estimate that the area delivers the basic nutrition of about 1400 households, which equals 2.7 million USD, and that the mangrove biomass in the area contains 2.1 million Mg C, amounting to 50.9 million USD, if it were paid as certificates. In addition to those figures, we provide high-resolution maps showing which areas are more valuable for the two respective ES, information that could help inform management strategies in the future.


1976 ◽  
Vol 54 (4) ◽  
pp. 526-530 ◽  
Author(s):  
M. B. Fenton ◽  
G. K. Morris

By using a 'black light' and playback of sounds made by foraging insectivorous bats, we examined opportunistic feeding behavior of bats near Camp Verde, Arizona, between 1 and 10 June 1975. Bats were significantly most active during 15-min periods when the light was on and insects were aggregated over it. Bats feeding over the light selectively pursued and captured larger insects, apparently ignoring the smaller ones. Bats did not respond to sounds simulating feeding buzzes of bats, but showed a slight response to the foraging sounds of other bats. Opportunistic feeding by insectivorous bats allows effective exploitation of patchily distributed food resources and can lead to selective feeding when 'hatches' of insects are involved. Opportunistic feeding is not incompatible with selective feeding, and may eventually be established as a strategy common to most insectivorous bats.


2017 ◽  
Vol 284 (1863) ◽  
pp. 20171248 ◽  
Author(s):  
Ben Dantzer ◽  
Ines Braga Goncalves ◽  
Helen C. Spence-Jones ◽  
Nigel C. Bennett ◽  
Michael Heistermann ◽  
...  

In cooperative breeders, aggression from dominant breeders directed at subordinates may raise subordinate stress hormone (glucocorticoid) concentrations. This may benefit dominants by suppressing subordinate reproduction but it is uncertain whether aggression from dominants can elevate subordinate cooperative behaviour, or how resulting changes in subordinate glucocorticoid concentrations affect their cooperative behaviour. We show here that the effects of manipulating glucocorticoid concentrations in wild meerkats ( Suricata suricatta ) on cooperative behaviour varied between cooperative activities as well as between the sexes. Subordinates of both sexes treated with a glucocorticoid receptor antagonist (mifepristone) exhibited significantly more pup protection behaviour (babysitting) compared to those treated with glucocorticoids (cortisol) or controls. Females treated with mifepristone had a higher probability of exhibiting pup food provisioning (pup-feeding) compared to those treated with cortisol. In males, there were no treatment effects on the probability of pup-feeding, but those treated with cortisol gave a higher proportion of the food they found to pups than those treated with mifepristone. Using 19 years of behavioural data, we also show that dominant females did not increase the frequency with which they directed aggression at subordinates at times when the need for assistance was highest. Our results suggest that it is unlikely that dominant females manipulate the cooperative behaviour of subordinates through the effects of aggression on their glucocorticoid levels and that the function of aggression directed at subordinates is probably to reduce the probability they will breed.


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