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Food Preferences (food + preference)
Selected AbstractsFood preferences and the value of animal food for the carabid beetle Amara similata (Gyll.) (Col., Carabidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2005S. Fawki Abstract:, Several studies have shown that the mainly granivorous carabid beetles, e.g. Amara spp., include animal food in their diet to a considerable extent. We therefore hypothesized that the performance of these beetles would be enhanced by dietary mixing including both seeds and animal food. In order to test this, we conducted laboratory feeding experiments with adults and larvae of Amara similata. Both adults and larvae were subjected to different diet treatments including: seeds, houseflies, grasshoppers, earthworms, slugs and snails in pure and mixed diets. Larval survival, development time, pupal and teneral weights were used as indicators of food quality for the larvae. For the adult beetles, mass change was used as an indicator of food quality. We found seeds to be high-quality food, while all pure animal diets were of low quality for both adults and larvae. Animal foods added to the seed diet had both positive and negative effects. A mixed diet of all foods enhanced the mass gain of adults compared with the seed diet, but reduced larval performance dramatically. Earthworms and grasshoppers added to seeds increased the pupal and teneral weights, while reduced larval survival. Thus, A. similata is omnivorous with a mainly granivorous feeding habit. It may gain benefits on some fitness parameters and incur costs on others from preying or scavenging on animal food. Therefore, the overall fitness consequences of a mixed seed-animal diet are uncertain. [source] Food preferences of wild mountain gorillasAMERICAN JOURNAL OF PRIMATOLOGY, Issue 10 2008Jessica Ganas Abstract Determining the nutritional and phenolic basis of food preference is important for understanding the nutritional requirements of animals. Preference is a measure of which foods would be consumed by an animal if there was no variation in availability among food items. From September 2004 to August 2005, we measured the food preferences of four wild mountain gorilla groups that consume foliage and fruit in Bwindi Impenetrable National Park, Uganda, to determine what nutrients and phenols are preferred and/or avoided. To do so, we asked the following questions: (1) Which plant species do the gorillas prefer? (2) Considering the different plant parts consumed of these preferred species, what nutrients and/or phenols characterize them? (3) Do the nutritional and phenolic characteristics of preferred foods differ among gorilla groups? We found that although some species were preferred and others were not, of those species found in common among the different group home ranges, the same ones were generally preferred by all groups. Second, all groups preferred leaves with relatively high protein content and relatively low fiber content. Third, three out of four groups preferred leaves with relatively high sugar amounts. Fourth, all groups preferred pith with relatively high sugar content. Finally, of the two groups tested, we found that the preferred fruits of one group had relatively high condensed tannin and fiber/sugar contents, whereas the other group's preferred fruits were not characterized by any particular nutrient/phenol. Overall, there were no differences among gorilla groups in nutritional and phenolic preferences. Our results indicate that protein and sugar are important in the diets of gorillas, and that the gorillas fulfil these nutritional requirements through a combination of different plant parts, shedding new light on how gorillas balance their diets in a variable environment. Am. J. Primatol. 70:927,938, 2008. © 2008 Wiley-Liss, Inc. [source] Maternal and littermate deprivation disrupts maternal behavior and social-learning of food preference in adulthood: Tactile stimulation, nest odor, and social rearing prevent these effectsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2006Angel I. Melo Abstract Maternal and littermate (social) separation, through artificial rearing (AR), disrupts the development of subsequent maternal behavior and social learning in rats. The addition of maternal-licking-like stimulation during AR, partially reverses some of these effects. However, little is know about the role of social stimuli from littermates and nest odors during the preweaning period, in the development of the adult maternal behavior and social learning. The purpose of this study was to examine the effects of peer- and peer-and-odor rearing on the development of maternal behavior and social learning in rats. Female pups were reared with mothers (mother reared,MR) or without mothers (AR) from postnatal day (PND) 3. AR rats received three different treatments: (1) AR-CONTROL group received minimal tactile stimulation, (2) AR-ODOR females received exposure to maternal nest material inside the AR-isolation-cup environment, (3) AR-SOCIAL group was reared in the cup with maternal nest material and a conspecific of the same-age and same-sex and received additional tactile stimulation. MR females were reared by their mothers in the nest and with conspecifics. In adulthood, rats were tested for maternal behavior towards their own pups and in a social learning task. Results confirm our previous report that AR impairs performance of maternal behavior and the development of a social food preference. Furthermore, social cues from a littermate, in combination with tactile stimulation and the nest odor, reversed the negative effects of complete isolation (AR-CONTROL) on some of the above behaviors. Exposure to the odor alone also had effects on some of these olfactory-mediated behaviors. These studies indicate that social stimulation from littermates during the preweaning period, in combination with odor from the nest and tactile stimulation, contributes to the development of affiliative behaviors. © 2006 Wiley Periodicals, Inc. Dev Psyshobiol 48: 209,219, 2006. [source] Genetic ablation of the mammillary bodies in the Foxb1 mutant mouse leads to selective deficit of spatial working memoryEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2005Konstantin Radyushkin Abstract Mammillary bodies and the mammillothalamic tract are parts of a classic neural circuitry that has been implicated in severe memory disturbances accompanying Korsakoff's syndrome. However, the specific role of mammillary bodies in memory functions remains controversial, often being considered as just an extension of the hippocampal memory system. To study this issue we used mutant mice with a targeted mutation in the transcription factor gene Foxb1. These mice suffer perinatal degeneration of the medial and most of the lateral mammillary nuclei, as well as of the mammillothalamic bundle. Foxb1 mutant mice showed no deficits in such hippocampal-dependent tasks as contextual fear conditioning and social transmission of food preference. They were also not impaired in the spatial reference memory test in the radial arm maze. However, Foxb1 mutants showed deficits in the task for spatial navigation within the Barnes maze. Furthermore, they showed impairments in spatial working memory tasks such as the spontaneous alternation and the working memory test in the radial arm maze. Thus, our behavioural analysis of Foxb1 mutants suggests that the medial mammillary nuclei and mammillothalamic tract play a role in a specific subset of spatial tasks, which require combined use of both spatial and working memory functions. Therefore, the mammillary bodies and the mammillothalamic tract may form an important route through which the working memory circuitry receives spatial information from the hippocampus. [source] Selective lesions of basal forebrain cholinergic neurons produce anterograde and retrograde deficits in a social transmission of food preference task in ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2002Anna Vale-Martínez Abstract We examined the performance of Long-Evans rats with 192 IgG-saporin lesions of the medial septum/vertical limb of the diagonal band (MS/VDB) or nucleus basalis magnocellularis/substantia innominata (NBM/SI), which removed cholinergic projections mainly to hippocampus or neocortex, respectively. We studied the effects of these lesions on anterograde and retrograde memory for a natural form of hippocampal-dependent associative memory, the social transmission of food preference. In a study of anterograde memory, MS/VDB lesions did not affect the immediate, 24-h or 3-week retention of the task. In contrast, NBM/SI lesions severely impaired immediate and 24-h retention. In a study of retrograde memory in which rats acquired the food preference 5 days or 1 day before surgery and they were tested 10,11 days after surgery, MS/VDB-lesioned rats showed striking memory deficits for the preference acquired at a long delay (5 days) before surgery, although all lesioned rats exhibited poorer retention on both retest sessions than on their pretest performance. Subsequent testing of new anterograde learning in these rats revealed no disrupting effects of lesions on a standard two-choice test. When rats were administered a three-choice test, in which the target food was presented along with two more options, NBM/SI-lesioned rats were somewhat impaired on a 24-h retention test. These results provide evidence that NBM/SI and MS/VDB cholinergic neurons are differentially involved in a social memory task that uses olfactory cues, suggesting a role for these neurons in acquisition and consolidation/retrieval of nonspatial declarative memory. [source] Grazing impact and phenology of the freshwater sponge Ephydatia muelleri and the bryozoans Plumatella emarginata and Fredericella sultana under experimental warmingFRESHWATER BIOLOGY, Issue 5 2009ANDREAS VOHMANN Summary 1.,Both the clearance rates (CR) and abundances of the freshwater sponge Ephydatia muelleri and the bryozoans Plumatella emarginata and Fredericella sultana were investigated from autumn to spring under different temperature regimes. The experiments were performed in bypass channels of the River Rhine (Cologne, Germany) in which temperature could be manipulated. 2.,The impact of temperature increase on CRs depends upon the grazer: E. muelleri showed a clear increase in CRs with increasing temperature whereas P. emarginata was not significantly affected by experimental warming. 3.,Distinct differences in food preference were found for the sponge (which is an efficient grazer of bacteria and small algae) and for the bryozoan P. emarginata (which feeds primarily on large algae, and with no significant grazing on bacteria). 4.,In contrast to their temperature-related patterns in CR, respiration of both P. emarginata and E. muelleri increased with temperature between 19 and 32 °C, suggesting that the risk of experiencing energy deficiency at high temperatures due to increased metabolic rates is particularly high for the bryozoan. 5.,A temperature elevation of 3 °C above the natural Rhine temperature resulted in a delay in the disappearance of active tissue and formation of resting stages for E. muelleri in autumn. This delay ranged from 8 (beginning of gemmulation) to 22 days (termination of gemmulation). In contrast, there was no distinct effect of warming on the disappearance of active zooids of the two bryozoan species in autumn. However, warming can positively affect the maintenance of active zooids during winter in F. sultana. In spring, the appearance of active zooids of P. emarginata was clearly stimulated by temperature elevations, whereas the hatching of both F. sultana and E. muelleri was hardly affected by warming. 6.,The study demonstrated different patterns in the thermal ecology of the two freshwater bryozoans and the sponge in comparison to other filter feeders, particularly mussels. Such patterns need to be considered when predicting the impact of temperature on pelagic-benthic coupling in aquatic habitats. [source] Construction of a taste-blind medaka fish and quantitative assay of its preference,aversion behaviorGENES, BRAIN AND BEHAVIOR, Issue 8 2008Y. Aihara In vertebrates, the taste system provides information used in the regulation of food ingestion. In mammals, each cell group within the taste buds expresses either the T1R or the T2R taste receptor for preference,aversion discrimination. However, no such information is available regarding fish. We developed a novel system for quantitatively assaying taste preference,aversion in medaka fish. In this study, we prepared fluorescently labeled foods with fine cavities designed to retain tastants until they were bitten by the fish. The subjects were fed food containing a mixture of amino acids and inosine monophosphate (AN food), denatonium benzoate (DN food) or no tastant (NT food), and the amounts of ingested food were measured by fluorescence microscopy. Statistical analysis of the fluorescence intensities yielded quantitative measurements of AN food preference and DN food aversion. We then generated a transgenic fish expressing dominant-negative G,i2 both in T1R-expressing and in T2R-expressing cells. The feeding assay revealed that the transgenic fish was unable to show a preference for AN food and an aversion to DN food. The assay system was useful for evaluating taste-blind behaviors, and the results indicate that the two taste signaling pathways conveying preferable and aversive taste information are conserved in fish as well as in mammals. [source] Behavioral characterization of P311 knockout miceGENES, BRAIN AND BEHAVIOR, Issue 7 2008Gregory A. Taylor P311 is an 8-kDa protein that is expressed in many brain regions, particularly the hippocampus, cerebellum and olfactory lobes, and is under stringent regulation by developmental, mitogenic and other physiological stimuli. P311 is thought to be involved in the transformation and motility of neural cells; however, its role in normal brain physiology is undefined. To address this point, P311-deficient mice were developed through gene targeting and their behaviors were characterized. Mutants displayed no overt abnormalities, bred normally and had normal survival rates. Additionally, no deficiencies were noted in motor co-ordination, balance, hearing or olfactory discrimination. Nevertheless, P311-deficient mice showed altered behavioral responses in learning and memory. These included impaired responses in social transmission of food preference, Morris water maze and contextual fear conditioning. Additionally, mutants displayed altered emotional responses as indicated by decreased freezing in contextual and cued fear conditioning and reduced fear-potentiated startle. Together, these data establish P311 as playing an important role in learning and memory processes and emotional responses. [source] Autism-like behavioral phenotypes in BTBR T+tf/J miceGENES, BRAIN AND BEHAVIOR, Issue 2 2008H. G. McFarlane Autism is a behaviorally defined neurodevelopmental disorder of unknown etiology. Mouse models with face validity to the core symptoms offer an experimental approach to test hypotheses about the causes of autism and translational tools to evaluate potential treatments. We discovered that the inbred mouse strain BTBR T+tf/J (BTBR) incorporates multiple behavioral phenotypes relevant to all three diagnostic symptoms of autism. BTBR displayed selectively reduced social approach, low reciprocal social interactions and impaired juvenile play, as compared with C57BL/6J (B6) controls. Impaired social transmission of food preference in BTBR suggests communication deficits. Repetitive behaviors appeared as high levels of self-grooming by juvenile and adult BTBR mice. Comprehensive analyses of procedural abilities confirmed that social recognition and olfactory abilities were normal in BTBR, with no evidence for high anxiety-like traits or motor impairments, supporting an interpretation of highly specific social deficits. Database comparisons between BTBR and B6 on 124 putative autism candidate genes showed several interesting single nucleotide polymorphisms (SNPs) in the BTBR genetic background, including a nonsynonymous coding region polymorphism in Kmo. The Kmo gene encodes kynurenine 3-hydroxylase, an enzyme-regulating metabolism of kynurenic acid, a glutamate antagonist with neuroprotective actions. Sequencing confirmed this coding SNP in Kmo, supporting further investigation into the contribution of this polymorphism to autism-like behavioral phenotypes. Robust and selective social deficits, repetitive self-grooming, genetic stability and commercial availability of the BTBR inbred strain encourage its use as a research tool to search for background genes relevant to the etiology of autism, and to explore therapeutics to treat the core symptoms. [source] Dissociation of food and opiate preference by a genetic mutation in zebrafishGENES, BRAIN AND BEHAVIOR, Issue 7 2006B. Lau Both natural rewards and addictive substances have the ability to reinforce behaviors. It has been unclear whether identical neural pathways mediate the actions of both. In addition, little is known about these behaviors and the underlying neural mechanisms in a genetically tractable vertebrate, the zebrafish Danio rerio. Using a conditioned place preference paradigm, we demonstrate that wildtype zebrafish exhibit a robust preference for food as well as the opiate drug morphine that can be blocked by the opioid receptor antagonist naloxone. Moreover, we show that the too few mutant, which disrupts a conserved zinc finger-containing gene and exhibits a reduction of selective groups of dopaminergic and serotonergic neurons in the basal diencephalon, displays normal food preference but shows no preference for morphine. Pretreatment with dopamine receptor antagonists abolishes morphine preference in the wildtype. These studies demonstrate that zebrafish display measurable preference behavior for reward and show that the preference for natural reward and addictive drug is dissociable by a single-gene mutation that alters subregions of brain monoamine neurotransmitter systems. Future genetic analysis in zebrafish shall uncover further molecular and cellular mechanisms underlying the formation and function of neural circuitry that regulate opiate and food preference behavior. [source] Do elevated atmospheric CO2 and O3 affect food quality and performance of folivorous insects on silver birch?GLOBAL CHANGE BIOLOGY, Issue 3 2010PETRI A. PELTONEN Abstract The individual and combined effects of elevated CO2 and O3 on the foliar chemistry of silver birch (Betula pendula Roth) and on the performance of five potential birch-defoliating insect herbivore species (two geometrid moths, one lymantrid moth and two weevils) were examined. Elevated CO2 decreased the water concentration in both short- and long-shoot leaves, but the effect of CO2 on the concentration of nitrogen and individual phenolic compounds was mediated by O3 treatment, tree genotype and leaf type. Elevated O3 increased the total carbon concentration only in short-shoot leaves. Bioassays showed that elevated CO2 increased the food consumption rate of juvenile Epirrita autumnata and Rheumaptera hastata larvae fed with short- and long-shoot leaves in spring and mid-summer, respectively, but had no effect on the growth of larvae. The contribution of leaf quality variables to the observed CO2 effects indicate that insect compensatory consumption may be related to leaf age. Elevated CO2 increased the food preference of only two tested species: Phyllobius argentatus (CO2 alone) and R. hastata (CO2 combined with O3). The observed stimulus was dependent on tree genotype and the measured leaf quality variables explained only a portion of the stimulus. Elevated O3 decreased the growth of flush-feeding young E. autumnata larvae, irrespective of CO2 concentration, apparently via reductions in general food quality. Therefore, the increasing tropospheric O3 concentration could pose a health risk for juvenile early-season birch folivores in future. In conclusion, the effects of elevated O3 were found to be detrimental to the performance of early-season insect herbivores in birch whereas elevated CO2 had only minor effects on insect performance despite changes in food quality related foliar chemistry. [source] Muscarinic receptor blockade in ventral hippocampus and prelimbic cortex impairs memory for socially transmitted food preferenceHIPPOCAMPUS, Issue 5 2009Anna Carballo-Márquez Abstract Acetylcholine is involved in learning and memory and, particularly, in olfactory tasks, but reports on its specific role in consolidation processes are somewhat controversial. The present experiment sought to determine the effects of blocking muscarinic cholinergic receptors in the ventral hippocampus (vHPC) and the prelimbic cortex (PLC) on the consolidation of social transmission of food preference, an odor-guided relational task that depends on such brain areas. Adult male Wistar rats were bilaterally infused with scopolamine (20 ,g/site) immediately after social training and showed impairment, relative to vehicle-injected controls, in the expression of the task measured 24 h after learning. Results indicated that scopolamine in the PLC completely abolished memory, suggesting that muscarinic transmission in this cortical region is crucial for consolidation of recent socially acquired information. Muscarinic receptors in the vHPC contribute in some way to task consolidation, as the rats injected with scopolamine in the vHPC showed significantly lower trained food preference than control rats, but higher than both chance level and that of the PLC-injected rats. Behavioral measures such as social interaction, motivation to eat, neophobia, or exploration did not differ between rats infused with scopolamine or vehicle. Such data suggest a possible differential role of muscarinic receptors in the PLC and the vHPC in the initial consolidation of a naturalistic form of nonspatial relational memory. © 2008 Wiley-Liss, Inc. [source] Tick prevalence and species diversity on Aldabran giant tortoises (Dipsochelys dussumieri) in relation to host range and host size in a restored ecosystem, KenyaAFRICAN JOURNAL OF ECOLOGY, Issue 3 2006Sharon Okanga Abstract Tick species density and diversity on Aldabran tortoises was investigated in relation to the habitat range and size of each tortoise. Identification of tick infestation patterns forms an important aspect of effective tick control. Ten Aldabran tortoises were de-ticked and monitored over the course of 2 months. Tick species found were Amblyomma sparsum, Amblyomma nuttalli, Amblyomma hebraeum and Boophilus decoloratus, with the most prevalent species found being A. sparsum. Tick loads varied considerably from 20 to 214 ticks per tortoise, with most ticks collected from the head/neck region. Tortoises ranging outside Haller Park had higher tick loads (70,214) compared with tortoises ranging within Haller Park (20,99). Tick load was not correlated with tortoise size. Results indicate that tick loads are related to the habitat range of the tortoises and may indirectly also be related to food preference and host food availability. Implications of the findings and appropriate tick control measures are discussed. Résumé On a étudié la densité et la diversité des espèces de tiques sur les tortues d'Aldabra, en relation avec la répartition et la taille de l'habitat de chaque tortue. L'identification des schémas d'infestation par les tiques est un aspect important du contrôle efficace des tiques. On a enlevé toutes les tiques de dix tortues d'Aldabra et on les a surveillées pendant deux mois. Les espèces trouvées étaient Amblyomma sparsum, Amblyomma nuttalli, Amblyomma hebraeum et Boophilus decoloratus, l'espèce prévalente étant A. sparsum. Le nombre de tiques variait considérablement, allant de 20 à 214 par tortue, le plus grand nombre étant récolté dans la région de la tête et du cou. Les tortues vivant en dehors du Haller Park étaient plus infestées par les tiques (70,214) que celles de l'intérieur du parc (20,99). L'infestation par les tiques n'était pas lièe à la taille des tortues. Les résultats montrent que les infestations sont liées à l'habitat des tortues et qu'elles peuvent être indirectement liées à leurs préférences alimentaires et à la disponibilité de la nourriture pour leurs hôtes. On discute des implications de ces découvertes et de mesures appropriées pour le contrôle des tiques. [source] Food preferences of wild mountain gorillasAMERICAN JOURNAL OF PRIMATOLOGY, Issue 10 2008Jessica Ganas Abstract Determining the nutritional and phenolic basis of food preference is important for understanding the nutritional requirements of animals. Preference is a measure of which foods would be consumed by an animal if there was no variation in availability among food items. From September 2004 to August 2005, we measured the food preferences of four wild mountain gorilla groups that consume foliage and fruit in Bwindi Impenetrable National Park, Uganda, to determine what nutrients and phenols are preferred and/or avoided. To do so, we asked the following questions: (1) Which plant species do the gorillas prefer? (2) Considering the different plant parts consumed of these preferred species, what nutrients and/or phenols characterize them? (3) Do the nutritional and phenolic characteristics of preferred foods differ among gorilla groups? We found that although some species were preferred and others were not, of those species found in common among the different group home ranges, the same ones were generally preferred by all groups. Second, all groups preferred leaves with relatively high protein content and relatively low fiber content. Third, three out of four groups preferred leaves with relatively high sugar amounts. Fourth, all groups preferred pith with relatively high sugar content. Finally, of the two groups tested, we found that the preferred fruits of one group had relatively high condensed tannin and fiber/sugar contents, whereas the other group's preferred fruits were not characterized by any particular nutrient/phenol. Overall, there were no differences among gorilla groups in nutritional and phenolic preferences. Our results indicate that protein and sugar are important in the diets of gorillas, and that the gorillas fulfil these nutritional requirements through a combination of different plant parts, shedding new light on how gorillas balance their diets in a variable environment. Am. J. Primatol. 70:927,938, 2008. © 2008 Wiley-Liss, Inc. [source] Maintenance of narrow diet breadth in the monarch butterfly caterpillar: response to various plant species and chemicalsENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2-3 2002Danel B. Vickerman Abstract In order to better understand the maintenance of a fairly narrow diet breadth in monarch butterfly larvae, Danaus plexippus L. (Lepidoptera: Nymphalidae: Danainae), we measured feeding preference and survival on host and non-host plant species, and sensitivity to host and non-host plant chemicals. For the plant species tested, a hierarchy of feeding preferences was observed; only plants from the Asclepiadaceae were more or equally preferred to Asclepias curassavica, the common control. The feeding preferences among plant species within the Asclepiadaceae are similar to published mean cardenolide concentrations. However, since cardenolide data were not collected from individual plants tested, definitive conclusions regarding cardenolide concentrations and plant acceptability cannot be made. Although several non-Asclepiadaceae were eaten in small quantities, all were less preferred to A. curassavica. Additionally, these non-Asclepiadaceae do not support continued feeding, development, and survival of first and fifth-instar larvae. Preference for a host versus a non-host (A. curassavica versus Vinca rosea) increased for A. curassavica reared larvae as compared to diet-reared larvae suggesting plasticity in larval food preferences. Furthermore, host species were significantly preferred over non-host plant species in bioassays using a host plant or sucrose as a common control. Larval responses to pure chemicals were examined in order to determine if host and non-host chemicals stimulate or deter feeding in monarch larvae. We found that larvae were stimulated to feed by some ubiquitous plant chemicals, such as sucrose, inositol, and rutin. In contrast, several non-host plant chemicals deterred feeding: caffeine, apocynin, gossypol, tomatine, atropine, quercitrin, and sinigrin. Additionally the cardenolides digitoxin and ouabain, which are not in milkweed plants, were neutral in their influence on feeding. Another non-milkweed cardenolide, cymarin, significantly deterred feeding. Extracts of A. curassavica leaves were tested in bioassays to determine which components of the leaf stimulate feeding. Both an ethanol extract of whole leaves and a hexane leaf-surface extract are phagostimulatory, suggesting the involvement of both polar and non-polar plant compounds. These data suggest that the host range of D. plexippus larvae is maintained by both feeding stimulatory and deterrent chemicals in host and non-host plants. [source] PERSPECTIVE: THE EVOLUTION OF WARNING COLORATION IS NOT PARADOXICALEVOLUTION, Issue 5 2005Nicola M. Marples Abstract Animals that are brightly colored have intrigued scientists since the time of Darwin, because it seems surprising that prey should have evolved to be clearly visible to predators. Often this self-advertisement is explained by the prey being unprofitable in some way, with the conspicuous warning coloration helping to protect the prey because it signals to potential predators that the prey is unprofitable. However, such signals only work in this way once predators have learned to associate the conspicuous color with the unprofitability of the prey. The evolution of warning coloration is still widely considered to be a paradox, because it has traditionally been assumed that the very first brightly colored individuals would be at an immediate selective disadvantage because of their greater conspicuousness to predators that are naive to the meaning of the signal. As a result, it has been difficult to understand how a novel conspicuous color morph could ever avoid extinction for long enough for predators to become educated about the signal. Thus, the traditional view that the evolution of warning coloration is difficult to explain rests entirely on assumptions about the foraging behavior of predators. However, we review recent evidence from a range of studies of predator foraging decisions, which refute these established assumptions. These studies show that: (1) Many predators are so conservative in their food preferences that even very conspicuous novel prey morphs are not necessarily at a selective disadvantage. (2) The survival and spread of novel color morphs can be simulated in field and aviary experiments using real predators (birds) foraging on successive generations of artificial prey populations. This work demostrates that the foraging preferences of predators can regularly (though not always) result in the increase to fixation of a novel morph appearing in a population of familiar-colored prey. Such fixation events occur even if both novel and familiar prey are fully palatable and despite the novel food being much more conspicuous than the familiar prey. These studies therefore provide strong empirical evidence that conspicuous coloration can evolve readily, and repeatedly, as a result of the conservative foraging decisions of predators. [source] Non-lethal predator effects on the performance of a native and an exotic crayfish speciesFRESHWATER BIOLOGY, Issue 12 2005PER NYSTRÖM Summary 1. I tested the hypothesis that the potential for non-lethal effects of predators are more important for overall performance of the fast-growing exotic signal crayfish (Pacifastacus leniusculus Dana) than for the slower growing native noble crayfish (Astacus astacus L.). I further tested if omnivorous crayfish switched to feed on less risky food sources in the presence of predators, a behaviour that could reduce the feeding costs associated with predator avoidance. 2. In a 2 month long outdoor pool experiment, I measured behaviour, survival, cheliped loss, growth, and food consumption in juvenile noble or signal crayfish in pools with either a caged predatory dragonfly larvae (Aeshna sp.), a planktivorous fish that do not feed on crayfish (sunbleak, Leucaspius delineatus Heckel), or predator-free controls. Crayfish had access to multiple food sources: live zooplankton, detritus and periphyton. Frozen chironomid larvae were also supplied ad libitum outside crayfish refuges, simulating food in a risky habitat. 3. Crayfish were mainly active during hours of darkness, with signal crayfish spending significantly more time outside refuges than noble crayfish. The proportion of crayfish outside refuges varied between crayfish species, time and predator treatment, with signal crayfish spending more time in refuges at night in the presence of fish. 4. Survival in noble crayfish was higher than in signal crayfish, and signal crayfish had a higher frequency of lost chelipeds, indicating a high level of intraspecific interactions. Crayfish survival was not affected by the presence of predators. 5. Gut-contents analysis and stable isotope values of carbon (,13C) and nitrogen (,15N) indicated that the two crayfish species had similar food preferences, and that crayfish received most of their energy from feeding on invertebrates (e.g. chironomid larvae), although detritus was the most frequent food item in their guts. Signal crayfish guts were more full than those of noble crayfish, but signal crayfish in pools with fish contained significantly less food and fewer had consumed chironomids compared with predator-free controls. Length increase of signal crayfish (35%) was significantly higher than of noble crayfish (20%), but signal crayfish in pools with fish grew less than in control pools. 6. This short-term study indicates that fish species that do not pose a lethal threat to an organism may indirectly cause reductions in growth by affecting behaviour and feeding. This may occur even though prey are omnivorous and have access to and consume multiple food sources. These non-lethal effects of predators are expected to be particularly important in exotic crayfish species that show a general response to fish, have high individual growth rates, and when their feeding on the most profitable food source is reduced. [source] Geomorphology and fish assemblages in a Piedmont river basin, U.S.A.FRESHWATER BIOLOGY, Issue 11 2003D. M. Walters Summary 1.,We investigated linkages between fishes and fluvial geomorphology in 31 wadeable streams in the Etowah River basin in northern Georgia, U.S.A. Streams were stratified into three catchment sizes of approximately 15, 50 and 100 km2, and fishes and geomorphology were sampled at the reach scale (i.e. 20,40 times stream width). 2.,Non-metric multidimensional scaling (NMDS) identified 85% of the among-site variation in fish assemblage structure and identified strong patterns in species composition across sites. Assemblages shifted from domination by centrarchids, and other pool species that spawn in fine sediments and have generalised food preferences, to darter-cyprinid-redhorse sucker complexes that inhabit riffles and runs, feed primarily on invertebrates, and spawn on coarser stream beds. 3.,Richness and density were correlated with basin area, a measure of stream size, but species composition was best predicted (i.e. |r| between 0.60,0.82) by reach-level geomorphic variables (stream slope, bed texture, bed mobility and tractive force) that were unrelated to stream size. Stream slope was the dominant factor controlling stream habitat. Low slope streams had smaller bed particles, more fines in riffles, lower tractive force and greater bed mobility compared with high slope streams. 4.,Our results contrast with the ,River Continuum Concept' which argues that stream assemblages vary predictably along stream size gradients. Our findings support the ,Process Domains Concept', which argues that local-scale geomorphic processes determine the stream habitat and disturbance regimes that influence stream communities. [source] Diet and food preferences of the endangered Bearded Vulture Gypaetus barbatus: a basis for their conservationIBIS, Issue 2 2009ANTONI MARGALIDA The Bearded Vulture Gypaetus barbatus population in the Pyrenees is managed using feeding stations to increase breeding success and reduce mortality in the pre-adult population. Nevertheless, very little quantitative and qualitative information has been published on such basic aspects of the species' ecology as feeding habits and dietary preferences. This study investigated both aspects through direct and unbiased observation of breeding Bearded Vultures during the chick-rearing period. Bearded Vulture diet comprises mammals (93%), birds (6%) and reptiles (1%), with medium-sized ungulates (mainly sheep/goats) the most important species in the diet (61%, n = 677). Prey items were not selected in proportion to their availability, with the remains of larger species (cows and horses) being avoided, probably due to the variable cost/benefit ratios in handling efficiency, ingestion process and transport. There is no relationship between the proportion of sheep limbs in the diet and the proximity of feeding stations, suggesting that these sites are probably less important for breeding adults than for the pre-adult population. On the other hand, diet specificity seems related to productivity, with territories with greater trophic breadth being those with higher fecundity. Bearded Vultures prefer to eat limbs, although meat remains (provided principally by small mammals) can play an important role in guaranteeing breeding success during the first few weeks after hatching. The management of carrion provided by animals that die naturally in extensive livestock practices and the remains of wild ungulates which have died naturally or by human hunting, are important conservation tools for the Bearded Vulture and other carrion-eating species. [source] Determinants and adequacy of food consumption of children in La Trinidad, the PhilippinesINTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 3 2007Nienke Blijham Abstract In the Philippines, vitamin A and vitamin C deficiencies, particularly among children, is a pressing health problem. This article reports the results of a research project that aimed at gaining insight into the factors in the household context that influence food intake of children and the role these factors play in vitamin A and vitamin C deficiencies. The research was carried out in La Trinidad, an urban area in the Philippines, where sufficient nutritious foods proved to be available. The results show that household income has only a minor impact on nutritional status. The nutritional status of children seems to be primarily influenced by their food preferences and the level of parental control on their food intake. [source] Dietary Approaches to Stop Hypertension (DASH) diet: applicability and acceptability to a UK populationJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 1 2010K. E. Harnden Abstract Background:, The Dietary Approaches to Stop Hypertension (DASH) diet is widely promoted in the USA for the prevention and treatment of high blood pressure. It is high in fruit and vegetables, low-fat dairy and wholegrain foods and low in saturated fat and refined sugar. To our knowledge, the use of this dietary pattern has not been assessed in a free-living UK population. Methods:, The DASH diet was adapted to fit UK food preferences and portion sizes. Fourteen healthy subjects followed the adapted DASH diet for 30 days in which they self-selected all food and beverages. Dietary intake was assessed by 5-day food diaries completed before and towards the end of the study. Blood pressure was measured at the beginning and end of the study to assess compliance to the DASH style diet. Results:, The DASH diet was easily adapted to fit with UK food preferences. Furthermore, it was well tolerated and accepted by subjects. When on the DASH style diet, subjects reported consuming significantly (P < 0.01) more carbohydrate and protein and less total fat (5%, 6% and 9% total energy, respectively). Sodium intakes decreased by 860 mg day,1 (P < 0.001). Systolic and diastolic blood pressure decreased significantly (P < 0.05) by 4.6 and 3.9 mmHg, respectively when on the DASH style diet. Conclusions:, The DASH style diet was well accepted and was associated with a decrease in blood pressure in normotensive individuals and should be considered when giving dietary advice to people with elevated blood pressure in the UK. [source] The importance of exposure for healthy eating in childhood: a reviewJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 4 2007L. Cooke Abstract Children's food preferences are strongly associated with their consumption patterns. Identifying the factors that influence preferences is therefore crucial to the development of effective interventions to improve children's diets. Perhaps the most important determinant of a child's liking for a particular food is the extent to which it is familiar. Put simply, children like what they know and they eat what they like. From the very earliest age, children's experiences with food influence both preferences and intake, and research suggests that the earlier and broader that experience, the healthier the child's diet. Laboratory studies of children's food acceptance have indicated that repeated opportunities to taste unfamiliar foods results in increased liking and consumption. In order to investigate whether these results can be replicated in real-world situations, a series of naturalistic studies testing the efficacy of exposure-based interventions have been carried out. In a school-based study large increases in liking and intake of raw red pepper were seen in 5- to 7-year olds and two further studies, in which mothers used exposure techniques to increase children's acceptance of vegetables, achieved similar results. If future large-scale interventions prove to be successful, training could be offered to health professionals or directly to parents themselves. [source] Nutrient intake of children consuming breakfast at school clubs in LondonJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 5 2003S. Waddington Introduction: Research into the effectiveness of breakfast clubs has most commonly focused on social benefits to the child and school, such as improved attendance at school, punctuality and improved concentration levels in the classroom (UEA, 2002). Limited research has been undertaken to investigate the nutritional value of the breakfast foods on offer, or the nutritional content of foods consumed by the child. The aim of this study was to find out what children eat and drink at school breakfast clubs in London. Method: The sample population consisted of 98 children (39 boys and 59 girls) aged 5,11 years attending four primary schools in London. Data were collected about the food on offer and the pricing of different food items, demographic data about the children attending the school club, qualitative data on food preferences and a weighed food intake on two different occasions for each child. Statistical tests (anova and chi-squared tests) and nutrient analysis using Comp-Eat were carried out. Results: The average nutrient content of the breakfast meal consumed was 330 kcal, 12 g protein, 11 g fat and 49 g carbohydrate. Variation was seen between schools. Generally intakes of vitamin C, calcium and sodium were high and intakes of iron were average. anova between schools showed statistically significant results for a number of nutrients , protein, fat, saturated fat, carbohydrate, sugar, calcium and sodium. Boys were consuming statistically significantly more fat, saturated fat and calcium than girls. One in five children did not have a drink at breakfast. Menu options and pricing of food items varied between the schools and it was noted to influence children's food choice and consumption. Mean energy intakes equated to 18% of the estimated average requirement for boys and 20% for girls, with girls consuming more carbohydrate and sugar, and boys consumed more fat and protein. Discussion: The findings suggest that careful planning of menus should be undertaken with cereal-based options being offered daily and cooked options only occasionally, and that healthier eating messages can be incorporated effectively into school clubs when supported by the whole school approach to healthy eating. Conclusion: Food offered at school breakfast clubs can contribute substantial nutrients to a child's daily intake and therefore a varied menu, and guided food choices, should be developed incorporating healthier nutrient rich options. This work was supported by Brooke Bond working in partnership with the BDA Community Nutrition Group. [source] An investigation into food preferences and the neural basis of food-related incentive motivation in Prader,Willi syndromeJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 9 2006E. C. Hinton Abstract Background Research into the excessive eating behaviour associated with Prader,Willi syndrome (PWS) to date has focused on homeostatic and behavioural investigations. The aim of this study was to examine the role of the reward system in such eating behaviour, in terms of both the pattern of food preferences and the neural substrates of incentive in the amygdala and orbitofrontal cortex (OFC). Method Participants with PWS (n = 18) were given a food preference interview to examine food preferences and to inform the food-related incentive task to be conducted during the neuroimaging. Thirteen individuals with PWS took part in the positron emission tomography (PET) study, the design of which was based on a previous study of non-obese, non-PWS controls. For the task, participants were asked to consider photographs of food and to choose the food they would most like to eat in two conditions, one of high and one of low incentive foods, tailored to each participant's preferences. For comparison of the food preference data, 12 non-PWS individuals were given one part of the interview. Results Individuals with PWS expressed relative liking of different foods and showed preferences that were consistent over time, particularly for sweet foods. The participants with PWS did give the foods in the high incentive condition a significantly higher incentive value than the foods in the low incentive condition. However, activation of the amygdala and medial OFC was not associated with the prospect of highly valued foods as predicted in those with PWS. Conclusions It would appear that incentive motivation alone plays a less powerful role in individuals with PWS than in those without the syndrome. This is likely to be due to the overriding intrinsic drive to eat because of a lack of satiety in those with PWS, and the impact of this on activity in the incentive processing regions of the brain. Activity in such reward areas may not then function to guide behaviour selectively towards the consumption of high preference foods. [source] Proboscis morphology and food preferences in nymphalid butterflies (Lepidoptera: Nymphalidae)JOURNAL OF ZOOLOGY, Issue 1 2001H. W. Krenn Abstract Many species of nymphalid butterflies only exceptionally visit flowers and feed instead on tree sap, juice of rotting fruits and other decaying substances. To investigate whether the proboscis morphology of these non-flower-visiting Nymphalidae differs from that of nectarivorous butterflies, representatives from 64 nymphalid species with known feeding preferences were examined. Morphometric comparison of the proboscis revealed characteristic differences in proboscis length, tip-region length, wall composition, and number and shape of proboscis sensilla between these two feeding guilds. The investigated non-flower-visiting species belonging to Apaturinae, Limenitidinae, Morphinae, Brassolinae, Nymphalinae and Satyrinae, possess a relatively short and light-coloured proboscis which has a long tip-region with a great number of club-shaped sensilla styloconica. Densely arranged, these sensilla form a flat brush located laterally from the openings into the food canal on the dorsal side of the tip-region. Among the non-flower-visiting species, a second type of proboscis was found in fruit-feeding Charaxinae the stout tip-region of which is equipped with more widely spaced sensilla styloconica. The investigated flower-visiting Heliconiinae, Nymphalinae, Satyrinae, Danainae and Ithomiinae are characterized by a slender, darker-coloured proboscis with a rather short tip-region bearing fewer sensilla styloconica in a loose arrangement. Discriminant analysis revealed that the tip-region length, the number of sensilla styloconica and the relative proboscis length are the most important discriminating variables between the flower-visiting and the non-flower-visiting species. The proboscis morphology of nymphalid butterflies corresponds with certain feeding habits and allow us to make predictions on their food preferences. The ,brush-tipped' proboscis seems to have a functional role in the accumulation of fluid and the uptake of liquid from wet surfaces such as rotting fruits or tree sap. We conclude from the phylogeny of the examined taxa that this derived proboscis tip morphology evolved several times independently as an adaptation to the exploitation of new food resources. [source] Meal and food preferences of nutritionally at-risk inpatients admitted to two Australian tertiary teaching hospitalsNUTRITION & DIETETICS, Issue 1 2008Angela VIVANTI Abstract Aim:, To determine preferences for meals and snack of long-stay patients and hospitalised patients with increased energy and protein requirements. Methods:, Using consistent methodology across two tertiary teaching hospitals, a convenience sample of adult public hospital inpatients with increased energy and protein requirements or longer stays (seven days or more) were interviewed regarding meal and snack preferences. Descriptive reporting of sample representativeness, preferred foods and frequency of meals and between meal snacks. Results:, Of 134 respondents, 55% reported a decreased appetite and 28% rated their appetite as ,poor'. Most felt like eating either nothing (42%) or soup (15%) when unwell. The most desired foods were hot meal items, including eggs (31%), meat dishes (20%) and soup (69%). Of items not routinely available, soft drink (7.6%) and alcohol (6.7%) were most commonly desired during admission. Almost half (49%) reported difficulty opening packaged food and a majority (81%) indicated finger foods were easy to eat. Conclusion:, Appetites during admission were frequently lower than usual. Responses encourage consideration of eggs, meat dishes and soups for long-stayers or those with high-energy, high-protein needs. Easy to consume but not routinely offered, between meal items, such as soup, juice, cake, soft drink or Milo could be explored further to enhance oral intakes. [source] Exploring parents' perceptions of television food advertising directed at children: A South Australian studyNUTRITION & DIETETICS, Issue 1 2007Joyce IP Abstract Objective:, To increase our understanding of parents' perceptions of the influence of television food advertising on children's food choices. Design:, Five focus group discussions. Subjects:, Thirty-two parents (24 women and eight men) of children attending primary school. Setting: Adelaide, South Australia. Data analyses:, The focus group discussions were taped and transcribed and coded as themes. Transcripts were verified and coding was audited. All researchers met regularly to analyse data and reach consensus on emergent themes (researcher triangulation). Results:, Parents who participated in the study indicated that television is a powerful source of information for children's food choices. Parents expressed concern about the negative influence of television food advertising on children's food preferences. They suggested that the current regulations governing television food advertising were not adequately enforced. Parents wanted to see an overall reduction in the volume of food advertisements directed at children, and an increase in advertisements promoting healthy foods. Parents expressed mixed views about banning food advertisements directed at children. Conclusion:, In order for television food advertising to be health-enhancing for children, parents in the study suggested the need for restrictions on advertising practices, tighter enforcement of existing regulations and an increase in healthy food advertisements. The present research shows that parents want to see changes in the current arrangements governing television food advertising to children. [source] The Effects of Exercise on Food Intake and Body Fatness: A Summary of Published StudiesNUTRITION REVIEWS, Issue 1 2007Sonya J. Elder MS Exercise has well-recognized health benefits, including reduction in risk factors for cardiovascular disease and type 2 diabetes. However, the extent to which exercise influences energy regulation and facilitates a reduction in body fat is less clear. This review summarizes published studies on the effects of different amounts of exercise on body fatness, energy intake, and food preferences in humans. The results show consistent effects of exercise on body fatness in the absence of prescribed dietary change, with a progressive loss of body fat associated with higher exercise energy expenditures in both men and women. In part, these effects appear to be mediated by a spontaneous reduction in hunger associated with participation in exercise. Insufficient data are available on whether there are changes in food preferences and taste perception that influence energy balance through macro-nutrient selection, so further studies in this area are needed. [source] Food choices and habitat use by the Tana River yellow baboons (Papio cynocephalus): a preliminary report on five years of dataAMERICAN JOURNAL OF PRIMATOLOGY, Issue 5 2009Vicki K. Bentley-Condit Abstract The Tana River Primate National Reserve, Kenya (TRPNR) yellow baboons' (Papio cynocephalus) long-term habitat usage and food preferences are relatively under-reported. The author presents a preliminary food catalog and analyses of 5 years of data (January 88,October 92; n=55 mo; 875 observation days; 4,893 hourly scans) for the Mchelelo troop (x,=75 individuals). The author predicted that the TRPNR baboons would spend more time on the much larger savanna, show a seasonal preference for fruits/seeds, and show rainfall-influenced food preferences. Although more time was spent on the proportionately larger savanna than in the forests, more than 42% of the observations occurred in forests that accounted for only 8.7% of the area regularly used by the baboons. Fruits/seeds consumption was high throughout the period and a significantly higher proportion of each month's observations reflected fruits/seeds rather than grasses/herbs/corms consumption. Two forest species' (Phoenix reclinata and Hyphaene compressa) were particularly important. Regression analysis showed fruits/seeds consumption predicted most of the grasses/herbs/corms consumption variance. There was no statistical difference in rainy vs. non-rainy season fruits/seeds or grasses/herbs/corms consumption. One implication of these data is the baboons' potential impact on the critically endangered Tana River mangabeys (Cercocebus galeritus), which also rely heavily on P. reclinata and H. compressa. Another is what the "savanna" designation may or may not tell us about baboons. Am. J. Primatol. 71:432,436, 2009. © 2009 Wiley-Liss, Inc. [source] Food preferences of wild mountain gorillasAMERICAN JOURNAL OF PRIMATOLOGY, Issue 10 2008Jessica Ganas Abstract Determining the nutritional and phenolic basis of food preference is important for understanding the nutritional requirements of animals. Preference is a measure of which foods would be consumed by an animal if there was no variation in availability among food items. From September 2004 to August 2005, we measured the food preferences of four wild mountain gorilla groups that consume foliage and fruit in Bwindi Impenetrable National Park, Uganda, to determine what nutrients and phenols are preferred and/or avoided. To do so, we asked the following questions: (1) Which plant species do the gorillas prefer? (2) Considering the different plant parts consumed of these preferred species, what nutrients and/or phenols characterize them? (3) Do the nutritional and phenolic characteristics of preferred foods differ among gorilla groups? We found that although some species were preferred and others were not, of those species found in common among the different group home ranges, the same ones were generally preferred by all groups. Second, all groups preferred leaves with relatively high protein content and relatively low fiber content. Third, three out of four groups preferred leaves with relatively high sugar amounts. Fourth, all groups preferred pith with relatively high sugar content. Finally, of the two groups tested, we found that the preferred fruits of one group had relatively high condensed tannin and fiber/sugar contents, whereas the other group's preferred fruits were not characterized by any particular nutrient/phenol. Overall, there were no differences among gorilla groups in nutritional and phenolic preferences. Our results indicate that protein and sugar are important in the diets of gorillas, and that the gorillas fulfil these nutritional requirements through a combination of different plant parts, shedding new light on how gorillas balance their diets in a variable environment. Am. J. Primatol. 70:927,938, 2008. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||||||||