Single Food Item Research Articles

Sampling and information acquisition by western scrub-jays, Aphelocoma californica

Animals often make choices based on cues that provide uncertain information about the value of alternative options. To examine how this uncertainty affects sampling behaviour, western scrub-jays were studied in the field during selection of single food items to scatter-hoard. Nine habituated birds were videotaped at feeders during repeated presentations of pairs of unshelled peanuts that varied in size. Jays initially scanned the peanuts before picking one up and in 38% of trials handled both, often switching repeatedly between them before making a choice. The jays preferred heavier nuts, which contained a larger food reward, but made errors particularly when mass differences were small. In addition, when choosing which nut to pick up first the birds discriminated mass relatively less accurately when the peanuts were larger. When mass differences were small the birds were more likely to handle both nuts before choosing. Handling both nuts raised the probability of selecting the heavier one by 20%, but did not increase the rate of food acquisition above that obtainable by scanning because it also increased time spent choosing. These results confirm recent suggestions that animals facing difficult discriminations may increase the accuracy of choice by sampling additional cues.

A mixed foodborne outbreak with Salmonella heidelberg and Campylobacter jejuni in a nursing home.

To investigate a mixed Salmonella heidelberg and Campylobacter jejuni foodborne outbreak in a nursing home. Retrospective cohort study with a nested case-control design. Cases were defined by positive stool-culture results. Controls needed to be both asymptomatic and culture-negative. Residents of a 580-bed nursing home in Brooklyn, New York. Of the 580 residents, 119 (21%) developed illness. Of the 93 symptomatic patients who submitted specimens, cultures were positive for S heidelberg in 24 (26%), C jejuni in 14 (15%), and both microorganisms in 25 (27%). Only the pureed diet was associated highly with infection by either Salmonella (odds ratio [OR], 17.6; 95% confidence interval [CI95], 4.8-68.7; P < .001), Campylobacter (OR, 13.3; CI95, 3.2-59.2; P < .001), or both organisms (OR, 8.9; CI95, 2.7-30.3; P < .001). Among the 42 pureed foods served during the 5 days before the outbreak, five meat or poultry items were associated most strongly with culture positivity. Of these five meat items, only a chopped-liver salad was implicated by the two employees reporting illness. A reported food-handling error occurred when ground, cooked chicken livers were placed in a bowl containing raw chicken-liver juices. Recommendations for proper cleaning and sanitizing of kitchen equipment to prevent cross-contamination between raw and cooked foods. Mixed foodborne outbreaks occur rarely. During this outbreak, contamination of a single food item with multiple bacterial pathogens was the likely source of transmission. Improper food-handling techniques that promote growth of one microorganism also allow growth of other pathogens that may be present. Because different sources and routes of transmission may be implicated for different pathogens, specific preventive measures may vary depending on the organisms involved.

What currency do scatter-hoarding gray jays maximize?

Gray jays (Perisoreus canadensis) cache thousands of food items during each summer for use during the subsequent winter. Previous work on the economics of gray jay scatter-hoarding behavior was based on the assumption that the jays maximize the rate at which they store food energy; alternative currencies were not considered. Here we develop and test models based on two currencies, net rate (net recoverable energy stored per unit time) and efficiency (recoverable energy stored per unit energy expended). Our experiment involved providing gray jays with two options. After collecting a single food item upon arrival at a feeding apparatus, a jay could wait for two additional food items to become (simultaneously) available and then transport all three items for storage in scattered arboreal sites. Alternatively, the jay could immediately transport the single item to a storage site and return to the source repeatedly for additional single-item loads. By incrementally increasing the amount of time jays were required to wait for multipleitem loads, we were able to determine how long jays would wait before switching from multiple- to single-item caching trips. In contrast with the finding in a variety of species that efficiency-maximization models provide a better account of foraging behavior, the net rate-maximization model was a better predictor of the jays' switching point than was the efficiency-maximization model (Figs. 2 and 3). We discuss these conflicting results in the context of recent theory that describes the conditions favoring rate- versus efficiency-maximizing behavior (Ydenberg et al. 1994).

長期経年栄養調査にもとづく食品摂取構造の分析

The purpose of this research is to identify the food intake structure in terms of breakfast, lunch and dinner. The research sample is a group of house-wives in a sub-urban rural area in the Chiba prefecture. The survey was conducted eleven times every year from 1978 to 1989 except 1988. Findings are followings. 1. Nutrition intake per person per day in these years shows similar trend with the National Nutrition Survey for every year. This sample is relevant to analyze as a sample of the Japanese population. 2. Although the total intake of the staple foods like rice, bread, noodle decreased in these 12 years, the intake of rice has been constant and showed major portion of the staples. The intake of bread is limited for breakfast. 3. In each year, the rice intake in a day is allocated about 30% for each meals and the rest for snacks between meals. 4n the other hand, bread and noodle shows too much variation from year to year to analyze as a single food item. 4. As the main sources of protein, the intake of fishes, meats and eggs have increased in the twelve years. While fishes and meats are mostly consumed at lunch and dinner, eggs are at breakfast. 5. Factor analysis for each meal was conducted using 13 food groups, in which rice, bread and noodle are collected into a item of grain. While the grain group does not show any significant role, the selection of protein sources is suggested as an important factor from the analysis. 6. This method based on each meal indicates a significant role for the further nutrition education at a community level.

Diet and Cancer of the Colon and Rectum: A Case-Control Study in China

A case-control study was carried out in Harbin city to assess the role of diet in the aetiology of colorectal cancer. A total of 336 incident cases of histologically confirmed colorectal cancer (111 colon cancer and 225 rectal cancer) and an equal number of controls with other non-neoplastic diseases were interviewed in hospital wards. Data concerning the average frequency of consumption and amount consumed of single food items were obtained by a dietary history questionnaire. Odds ratios and their confidence limits were computed. Multiple regression for risk status was also used. Vegetables, particularly green vegetables, chives and celery, have a strong protective effect against colorectal cancer. Reduced consumption of meat, eggs, bean products and grain was associated with increasing risk for cancer of the rectum. Alcohol intake was found to be an important risk factor for developing colon cancer and male rectal cancer.

Studies on the ingestion of radiocesium from contaminated pastures in reindeer

Grazing experiment with two oesophageally fistulated reindeer were conducted during June to August 1987 in the Jotunheimen mountain range (1000-1400 m). Grazing in 4 different plant communities was compared: Mesotrophic birch forest dominated by heather, Oligotrophic community with poor snow- cover dominated by heather and Dwarf birch, Oligotrophic community with moderate snowcover domi­ nated by lichens and sedges and a snowbed community dominated by Least willow and lichens. The radioactivity in food samples obtained from the fistula changed through the summer and differed be­ tween communities, from 8000 Bq/kg dry matter to 49000 Bq/kg dry matter. The major factor responsible for these changes was variations in the amounts of lichens ingested. Lichens beside mosses had the highest levels of radiocesium and consequently the amount of lichens consumed was the major single food item responsible for high intake of radioactivity.

Supermarket savvy

A myriad of front-of-package (FOP) nutrition labeling systems have been developed by both food retailers (e.g., Walmart, Safeway, Hannaford) and manufacturers (e.g., Kellogg's, General Mills) to help consumers identify more healthful options at the point-of-purchase. Given the uniqueness of these different approaches, two studies examine the effects of alternative FOP systems on shoppers’ product evaluations, choices, and retailer evaluations. When a single food item is evaluated in isolation, both the reductive and evaluative systems had a positive effect on product evaluations. However, when several choice options are presented simultaneously in a realistic retail environment, the evaluative (reductive) system has a stronger (weaker) influence on product evaluation and choice. Results also show that FOP nutrition labeling systems have both direct and moderating effects on attitude toward the retailer and perceived retailer concern for shoppers. These retailer-related outcomes, in turn, mediate the effects of the labeling system on shoppers’ intentions to patronize the retailer. Results suggest that FOP nutrition labeling may help retailers build a non-price competitive advantage.

Mutagenic and antimutagenic factor(s) extracted from a desert mushroom using different solvents.

A desert mushroom called Al-faga (Tirmania pinoyi) was sequentially extracted with boiling water, chloroform and ethanol under reflux conditions. The water extract was freeze-dried while the organic solvents were fully evaporated to obtain residues, which were redissolved in dimethylsulphoxide and then tested for mutagenicity in the Ames assay using the Salmonella tester strains TA98 and TA100. The aqueous extract failed to show any mutagenic activity while the chloroform extract proved to be mutagenic with and without metabolic activation. The ethanol extract was not mutagenic in the same tests. However, ethanol extract combined with known carcinogens like benzo[a]pyrene or 7,12-dimethyl-benz[a]anthracene (with metabolic activation) inhibited the carcinogen-induced mutagenicity in a dose-dependent manner. These results show that both mutagens and antimutagens may be extracted from a single food item by using different solvents.

Dietary Shifts in the Queen Triggerfish, Balistes vetula, in the Absence of its Primary Food Item, Diadema antillarum

Abstract. The long‐spined sea urchin Diadema antillarum has been reported to be the major food item of the queen triggerfish, Balistes vetula in the Caribbean. This sea urchin has undergone a massive mortality on reefs throughout the Caribbean during 1983. The dietary habits of twenty‐three queen triggerfish from patch reef habitats in Belize were examined. It was found that crabs and chitons now form the major dietary items when D. antillarum is not available. It is suggested that this predator, which was previously specialized on a single food item, is able to shift resource utilization in the absence of its primary food source, and that the queen triggerfish can capture diverse prey from a wide variety of habitats.

Comparisons of feeding behavior in captive squirrel and titi monkeys (Saimiri sciureus and Callicebus moloch).

This research investigated feeding behavior in captive squirrel monkeys (Saimiri sciureus) and titi monkeys (Callicebus moloch). In view of behavioral differences seen in natural environments, one might expect that feeding and foraging patterns draw upon different behavioral tendencies in the two species. Some of these tendencies were identified in this research. In the home cage, in the presence of abundant food, squirrel monkeys were rapid, wasteful, and relatively asocial feeders. Titis in the same setting were slower, more selective, thorough, and socially involved feeders. Passive sharing of food between titi pair-mates was common. When competition was increased by presenting a single food item, titis continued to rely on positive social interactions to obtain food; squirrel monkeys still relied mainly on asocial stratagems to obtain food. The species' food preferences in paired-comparison tests were quite similar, although their patterns of obtaining and consuming the foods were not. Squirrel monkeys took food more quickly but consumed less than titis. When the same foods were presented repetitively, squirrel monkeys remained more wasteful consumers and were satiated more quickly than titis, even with highly preferred foods. These differences are discussed in terms of their probable contributions to each species' modal foraging patterns in natural environments. The findings are placed in the framework of an adaptive profile for each species, based on data accumulated in a series of studies conducted over the last decade.

How marsh tits find their hoards: The roles of site preference and spatial memory.

Marsh tits (Parus palustris) store single food items in scattered locations and recover them hours or days later. Some properties of the spatial memory involved were analyzed in two laboratory experiments. In the first, marsh tits were offered 97 sites for storing 12 seeds. They recovered a median of 65% of them 2-3 hr later, making only two errors per seed while doing so. Over trials, they used some sites more often than others, but during recovery they were more likely to visit a site of any preference value if they had stored a seed there that day than if they had not. Recovery performance was much worse if the experimenters moved the seeds between storage and recovery. A fixed search strategy that had some of the same average properties as the tits' search behavior also did worse than the real birds. In Experiment 2, any tendency to visit the same sites on successive daily tests in the aviary was placed in opposition to memory for storage sites by allowing the tits to store more seeds 2 hr after storing a first batch. They tended to avoid individual storage sites holding seeds from the first batch. When the tits searched for all the seeds 2 hr later, they tended to recover more seeds from the second batch than from the first, i.e., there was a recency effect.

The food of suburban foxes (Vulpes vulpes), with special reference to London

AbstractThe food of foxes in suburban London was examined using stomach contents and den litter analysis. A great diversity of food was taken. Adult foxes killed nearer to the city centre were found to eat significantly fewer earthworms, domestic pets and wild mammals, but more scavenged food items, than foxes killed closer to the suburban fringe. Cubs killed closer to the city centre ate significantly fewer earthworms and insects, and more pet birds, pet mammals and scavenged food items than cubs killed nearer the periphery of the suburban area. Although seasonal trends in food selection were apparent, they were not as pronounced as those observed in studies of rural foxes. At no time of the year did a single food item predominate in the diet of adult foxes. Passeriformes were the most important single food item in the diet of young cubs, but there was no correlation between the number of Passeriformes eaten and their abundance, nor between annual changes in the abundance of small birds and mean fox birth litter size and productivity. Most foxes examined were in good body condition; there was no seasonal variation in body weight, although fat content did vary seasonally. A complementary survey in Bristol on losses of domestic pets to foxes revealed that 07% of pet cats and 80% of other pets kept outdoors were killed in a year. Damage to garden Crops was negligible.

Growth, food, and vulnerability to damage of the ctenophore Mnemiopsis mccradyi in its early life history stages

Newly hatched larvae of ctenophores are so delicate that they can be killed by copepods larger than nauplii. The larvae can withstand starvation for a week, but they need very high concentrations of nauplii to sustain rapid growth, and grow very slowly above 1 mm unless food of larger size is available. Over the first 7 days, larvae can double their weight seven times. Individual growth rate is extremely variable, even among the offspring of a single parent. Although newly hatched larvae have food in their guts &lt;30% of the time, a single food item (nauplius) of similar dry weight contains some 20 times more carbon than the ctenophore. As the larva grows, its consumption rate rapidly increases, the gut remaining full all the time, if food of larger size is available. These complex interactions of both high growth and high mortality of larvae are related to unnaturally high copepod concentrations in the laboratory. Patchiness in nature, however, at present ill defined quantitatively, may provide the explanation for the population’s success.

Some aspects of the biology of Petenia krausii Steindachner (Pisces: Cichlidae) in Lake Valencia, Venezuela

Petenia kraussii Steindachner (Pisces: Cichlidae) was collected from Lake Valencia, Venezuela from April 1973 to April 1974. A total of 457 specimens were examined for stomach contents, and 471 were analyzed for length‐weight relationship, sexual condition including fecundity and parasitism. P. kraussii is primarily a plankton feeder when small and utilizes benthic invertebrates after attaining about 10 cm standard length. The larvae of a benthic ephemeropteran, Campsurus sp. (Hexigenidae) was the most important single food item with gastropods and fish eggs also being found consistently in stomachs. No mature male fish were found, and only 17 of 471 fish could be identified as males, while 157 were females. Gravid females contained an estimated mean of 6266 eggs and matured at about 18 cm standard length and 100 g live weight. It was not possible to determine age from either scale or otoliths.

Social learning and the significance of mixed-species flocks of chickadees (Parus spp.)

The experiments described in this paper show that two species of chickadees learn from one another about the location and nature of potential feeding places when they are foraging together in mixed flocks in large aviaries. In the first experiment, I show that when an individual of one species finds a single food item, members of the other species modify their foraging behavior over the next few seconds so that they put more effort into searching near the site of the find. This applies to both species. Further, members of both species modify their foraging behavior when a bird of the other species searches in a place unsuccessfully. This response to an unsuccessful search is similar to, but weaker than, the response to a food find. The second experiment shows that when the two species are trained to forage in different positions in the experimental trees, they converge in their foraging behavior when they are put in mixed flocks, This is a result of copying. The third experiment shows that individuals of both species are more likely to discover a completely new foraging place if they are in the presence of an experienced bird of the other species.I discuss these results in relation to theories on the adaptive significance of flocking, and conclude that learning about potential feeding places from other species is an important function of mixed flocks, at least for some species. This does not exclude the possibility of other functions of mixed flocks.

THE FEEDING HABITS OF THE WHITEWINGED BLACK TERN ON LAKE KARIBA

Summary Bego, G. W. 1973. The feeding habits of the Whitewinged Black Tern on Lake Kariba. Ostrich 44: 149–153. The stomach contents of 33 Whitewinged Black Terns were examined over the period 26 August 1971 to 6 January 1972. The most important single food item was the sardine, Limnothrissa miodon. This sheds new light on the habits of this fish. The terns fed primarily during calm weather. Sardines are caught by hovering and diving. Fishes of the genera Haplochromis and Synodonlis, also appeared in the stomach contents. Terns taken from marginal localities appear not to feed on fish. Of the insects eaten Odonata are the most important aquatic source of food, while many terrestrial insects are eaten (Orthoptera, Hemiptera, Coleoptera, Isoptera). Such insects could have been found drifting on mats of Salvinia on which the terns rest, otherwise insects are either hawked or skimmed from the surface of the water.

Dietary zinc intake in man

1) The daily dietary zinc intake, as well as the amounts of zinc contained in individual meals, was determined in constant metabolic diets and in hospital diets. 2) The total zinc content in nine hospital diets was found to vary by more than a factor of 2, ranging from 7.0 to 16.3 mg zinc/day and averaging 11.3 mg zinc. The variability of the zinc content of these diets was due to differences in their composition, depending on the protein and carbohydrate content of the meals. 3) A total of 138 constant metabolic diets was analyzed for zinc over a 4-year period. The zinc content of these diets varied little, ranging from 11.6 to 12.7 mg/day in each of the 4 years and averaging 12.2 mg. 4) The analysis of diets of low and high protein content, as well as the analysis of single food items, indicated that the foods and diets high in protein were also high in zinc, whereas those foods and diets containing mostly carbohydrate, were found to be much lower in zinc and nitrogen content.

Food-borne epidemic of streptococcal pharyngitis at the United States Air Force Academy.

Abstract An explosive epidemic of pharyngitis due to Group A streptococci occurred among the cadets at the United States Air Force Academy during a seven-day period in the spring of 1968. Symptoms of streptococcal pharyngitis developed in over 1000 cadets during the course of the epidemic. Prompt institution of control measures probably confined the outbreak to the cadet wing and prevented extensive secondary spread. The epidemic strain was identified as a Group A, T-Type 12 streptococcus that could not be M-typed with available typing serums and may represent a new M-Type. An epidemiologic investigation incriminated a single food item as the vehicle of transmission. Nonsuppurative sequelae were not detected despite intensive surveillance.

Food Habits of the Feral House Cat in East-Central Texas

were shot along roadsides or in fields and woodlots with exception of three that were taken in steel traps and three that were found dead on road. Stomach contents are listed in Table 1. Errington (Jour. Mamm. 17(1): 64-65, 1936), in discussing food habits of southern Wisconsin house cats, is of opinion that manner in which cats are collected does not present a really true cross-section of food habits. Those cats that hunted along roadsides, in stubble and hayfields or those picked up dead on highways were readily seen and collected, while the elusive woodsdwellers, which are most likely to be feral and to have best access to avian prey, are seldom taken. These observations may hold true, in part at least, for Post Oak Region, although a larger number of song birds and quail frequent roadsides and more open fields and semi-brushy areas. Of 31 stomachs examined, two contained food that had apparently been fed to them by The owners. The cotton rat was taken more than any other single food item. This is probably because more cats were collected along roadsides and in brushy areas in and bordering pastures, where populations of TABLE 1.-QUALITATIVE ANALYSIS OF 31 STOMACHS OF FERAL HOUSE CATS COLLECTED IN THE CENTRAL POST OAK REGION