Foraging behaviour Research Papers - Academia.edu (original) (raw)

Mammals and birds adapt to prolonged fasting by mobilizing fat stores and minimizing protein loss. This strategy ends with an increase in protein utilization associated with behavioural changes promoting food foraging. Using the Zucker... more

Mammals and birds adapt to prolonged fasting by mobilizing fat stores and minimizing protein loss. This strategy ends with an increase in protein utilization associated with behavioural changes promoting food foraging. Using the Zucker rat as a model, we have investigated the effect of severe obesity on this pattern of protein loss during long-term fasting. Two interactions between the initial adiposity and protein utilization were found. First, protein conservation was more effective in obese than in lean rats: fatty rats had a three times lower daily nitrogen excretion and proportion of energy expenditure deriving from proteins, and a lower daily protein loss in various muscles. This phase of protein sparing is moreover nine times longer in the fatty rats. Second, obese animals did not show the late increase in nitrogen excretion that occurred in their lean littermates. Total body protein loss during starvation was larger in fatty rats (57% versus 29%) and, accordingly, total protein loss was greater in their muscles. At the end of the experiment, lean and obese rats had lost 98% and 82%, respectively, of their initial lipid reserves, and fatty rats still had an obese body composition. These results support the hypothesis that in severely obese humans and animals a lethal cumulative protein loss is reached long before the exhaustion of fat stores, while the phase of protein conservation is still continuing. In contrast, in lean rats, survival of fasting seems to depend on the availability of lipid fuels. The data also suggest that accumulation of too much fat in wild animals is detrimental for survival, because it eliminates the late phase of increase in nitrogen excretion that is linked to a food foraging behaviour anticipating a lethal depletion of body reserves.

... Data table »View table. Table 3. Frequencies of the main type of dives of thick-billed murres (Uria lomvia) and razorbills (Alca torda) at Gannet Islands, Labrador. ... 1993; Jones et al. 2002) differently. ... Clair et al. 2001;... more

... Data table »View table. Table 3. Frequencies of the main type of dives of thick-billed murres (Uria lomvia) and razorbills (Alca torda) at Gannet Islands, Labrador. ... 1993; Jones et al. 2002) differently. ... Clair et al. 2001; Williams and Ward 2006). ...

The present study describes the competition patterns among the most frequent epigeic ants in the Floresta Nacional Contendas do Sincorá, Bahia (shrubby ‘caatinga’ vegetation). Thirty-one sardine baits were disposed for 100 min at... more

The present study describes the competition patterns among the most frequent epigeic ants in the Floresta Nacional
Contendas do Sincorá, Bahia (shrubby ‘caatinga’ vegetation). Thirty-one sardine baits were disposed for 100 min at
intervals of 30 m. We registered 87 interactions of ants, a mean of 3 ant species per bait. Dinoponera quadriceps was
the most frequent (42.5 %), presented the higher mean time for discovering the baits (38 minutes) and the largest
distances between nest and bait (15.2 m). Dorymyrmex pr. pyramicus was the fastest (3 cm/s), whereas Pheidole
obscurithorax was the slowest (0.29 cm/s). These results suggest that the different strategies adopted by these ants
during foraging may be directly affecting species coexistence and, thus, guiding dominance patterns.

In this study the incidence of moths and beetles was examined from feces samples of bats that use different foraging behaviors. Twenty sites around the Fazenda Intervales, a Field Research Station located in São Paulo State, in... more

In this study the incidence of moths and beetles was examined from feces samples of bats that use different foraging behaviors. Twenty sites around the Fazenda Intervales, a Field Research Station located in São Paulo State, in southeastern Brazil were sampled. Feces were collected from bats caught in mist nets, Turtle Traps or hand nets and, in one case, from beneath a roost. Feces samples were taken from six species of bats: Micronycteris megalotis (Gray, 1842), Mimon bennettii (Gray, 1838), Furipterus horrens (F. Cuvier, 1828), Myotis riparius Handley, 1960, Myotis ruber (E. Geoffroy, 1806) and Histiotus velalus (I. Geoffroy, 1824). To record and describe the frequencies dominating bat echolocation calls, an Anabat II bat detector coupled with an Anabat ZCA interfaces and DOS laptop computers were used. The data show that Furipterus horrens feeds extensively on moths, as predicted from the features of its echolocation calls. Gleaning bats, whose echolocation calls are much less conspicuous to moths take a wide range of insect (and other) prey.

—In this paper an overview of the areas where the Bee Colony Optimization (BCO) and its variants are applied have been given. Bee System was identified by Sato and Hagiwara in 1997 and the Bee Colony Optimization (BCO) was identified by... more

—In this paper an overview of the areas where the Bee Colony Optimization (BCO) and its variants are applied have been given. Bee System was identified by Sato and Hagiwara in 1997 and the Bee Colony Optimization (BCO) was identified by Lucic and Teodorovic in 2001. BCO has emerged as a specialized class of Swarm Intelligence with bees as agents. It is an emerging field for researchers in the field of optimization problems because it provides immense problem solving scope for combinatorial and NP-hard problems. BCO is one of the benchmark systems portraying team work, collaborative work. BCO is a bottom-up approach of modeling where agents form global solution by optimizing the local solution.

The winter diet and foraging range of gentoo penguins, Pygoscelis papua, were studied at Kidney Cove, Falkland Islands. The mean wet mass of the 56 stomach-content samples collected from May to October was 32.7±47.4 g. The diet consisted... more

The winter diet and foraging range of gentoo penguins, Pygoscelis papua, were studied at Kidney Cove, Falkland Islands. The mean wet mass of the 56 stomach-content samples collected from May to October was 32.7±47.4 g. The diet consisted generally of cephalopods, crustaceans and fish, as well as two other molluscs. Among the six cephalopod species identified, the commercially fished Patagonian squid, Loligo gahi, had the highest abundance and was also the main prey by reconstituted mass (53% of the total reconstituted mass). Lobster krill, Munida gregaria, one of five species of crustaceans, was the most abundant prey species by frequency of occurrence and by number (68% and 60%, respectively). Rock cod, Patagonotothen ramsayi, accounted for the majority of the fish diet with 34% of the total reconstituted mass. Most prey species identified in the winter diet were also abundant diet components during the breeding season. However, the known biology of the prey species and their rate of digestion indicated that, in winter, adults may forage further offshore than during the breeding season. This assumption was supported by the results obtained from two birds satellite-tracked during the study period. Both birds remained mainly in inshore waters and returned frequently ashore, but one penguin foraged up to 276 km from the coast. The differences in the foraging behaviour of the two birds were reflected in significant differences with regard to time spent underwater, distance travelled per day and calculated travelling speed. Furthermore, the progress of cohorts of L. gahi over the winter is consistent with results from life-cycle studies in this region and suggests that birds have been foraging in the feeding grounds of L. gahi.

Understanding the mechanisms that link prey availability to predator behaviour and population change is central to projecting how a species may respond to future environmental pressures. We documented the behavioural responses and... more

Understanding the mechanisms that link prey availability to predator behaviour and population change is central to projecting how a species may respond to future environmental pressures. We documented the behavioural responses and breeding investment of macaroni penguins Eudyptes chrysolophus across five breeding seasons where local prey density changed by five-fold; from very low to highly abundant. When prey availability was low, foraging trips were significantly longer and extended overnight. Birds also foraged farther from the colony, potentially in order to reach more distant foraging grounds and allow for increased search times. These extended foraging trips were also linked to a marked decrease in fledgling weights, most likely associated with reduced rates of provisioning. Furthermore , by comparing our results with previous work on this population, it appears that lowered first-year survival rates associated, at least partially, with fledging masses were also evident for this cohort. This study integrates a unique set of prey density, predator behaviour and predator breeding investment data to highlight a possible behavioural mechanism linking perturbations in prey availability to population demography.

... a , Corresponding Author Contact Information , E-mail The Corresponding Author , Linda J. Keeling b , Inma Estevez b , c and Boris Bilčík b ... birds are older ([McAdie and Keeling, 2002], [Riedstra and Groothuis, 2002], [Rodenburg... more

... a , Corresponding Author Contact Information , E-mail The Corresponding Author , Linda J. Keeling b , Inma Estevez b , c and Boris Bilčík b ... birds are older ([McAdie and Keeling, 2002], [Riedstra and Groothuis, 2002], [Rodenburg and Koene, 2004] and [Chow and Hogan, 2005 ...

Flight performance and echolocation behaviour of the pond bat, Myotis dasycneme (Boie, 1825), were investigated over canals and a lake in the Netherlands. Multi-flash stereophotogrammetry, linked with synchronous recording of echolocation... more

Flight performance and echolocation behaviour of the pond bat, Myotis dasycneme (Boie, 1825), were investigated over canals and a lake in the Netherlands. Multi-flash stereophotogrammetry, linked with synchronous recording of echolocation calls, was used to reconstruct the three-dimensional flight paths of bats and to correlate flight behaviour with changes in pulse emission during echolocation. Echolocation calls during commuting flight at the canal were sigmoidal in structure, with an initial steep frequency modulated (FM) sweep followed by a more shallow sweep, ending with a second, rapid FM sweep. Similar calls were produced during the search phase of foraging, though longer duration quasi-CF (constant-frequency) calls, with longer interpulse intervals and much reduced initial and final FM sweeps, were produced by bats hunting over a large lake. Overall, calls were generally lower in frequency, with significantly longer pulse durations and interpulse intervals, compared with those of smaller trawling Myotis bats. Flight speeds were compared with predicted optima from aerodynamic models. Commuting bats exceeded predicted maximum range speed, which was considerably higher than that noted for other smaller species of trawling Myotis. Flight speed was significantly higher closer to the roost, at a narrower canal site. A negative correlation between wingbeat frequency and flight speed, and a facultative 1: 1 link between pulse emission and wingbeat during search phase were established. During commuting, the bats flew at a height above that which would normally confer substantial power savings through ground effect. It is argued that, by flying at a lower height, bats would compromise commuting speed. Echolocation calls produced during attempted prey capture were remarkably similar in design to those produced by those other Myotis species that forage in a similar fashion. Prey was detected at 2 m, and reaction distance was 1.8 m. Evidence of a physiological limit on pulse duration and interpulse interval during prey capture is presented. Overlap of emitted pulse and received echo may degrade the performance of echolocation in many bats, and overlap is generally avoided in M. dasycneme except perhaps when the bat is very close to the prey item.