Ants’ Food Examination

Sugar, salt and alum grains between 15 and 55 mg were deposited at different sites in the foraging ground of the ants Anoplolepis gracilipes and Paratrechina longicornis to study the examination processes the ants applied prior to carry these grains to the nest or refused at the site. It is revealed that, of the supplied 10 grains of these three substances A. gracilipes and P. longicornis examined only one sugar grain in most cases and two grains in few cases prior to carry a grain to the nest. Under similar situation an ant irrespective of species examined in most cases only one salt grain though few individuals examined 2 or 3 or 4 grains prior to have a decision either to carry one to the nest or to move elsewhere refusing the same at the site. Interestingly, an ant individual only in few cases examined only one alum grain but in most cases it examined 2, 3, 4 even up to all the 10 supplied alum grains scrupulously prior to refuse the same. Of the offered grain the ants procured 100 % sugar grains and 60 % salt grains from the sites to the nest while 100 % alum grains were refused at the sites following careful examination. As sugar, salt and alum grains look almost alike examination of all the alum grains was performed by the ants with a hope to get sugar grains, if any, from amongst these visually similar kinds of grains. This may be due to lack of food examination system at a precision level.     

Brazilian alcohol: Food versus fuel?

The creation of the ProAlcool (National Alcohol Programme) late in 1975 for the production of fuel alcohol has raised varied criticisms as to the possible consequences for food production in Brazil. This food ‘problem’ in Brazil is embedded in its socio-economic and political system. Agricultural production has kept ahead of population growth, but the main beneficiaries have been commodity export crops; the issue can be identified as ‘commodity export crop production versus crop production for the domestic market’ rather than ‘food versus fuel’. The possible effects of the ProAlcool on food production have been exaggerated and the real implications largely overlooked. The sugar and alcohol sector is today among Brazil's largest industries and, with all its faults, the ProAlcool remains the world's most successful biomass energy programme and as such its importance extends beyond Brazil's national boundaries. Biomass has been demonstrated by a Third World country to be a viable alternative or complement to oil on a national scale. Despite the current (1986) low oil prices an interministerial commission has recently recommended that the ProAlcool programme should be maintained.     

Do Tropical Frugivores Compete for Food?

In this paper I ask two questions: Is fruit ever limiting tovertebrate frugivores and, if so, do frugivores presently competefor food, either with closely- or distantly-related species?A brief review of the fruiting strategies of tropical plantsindicates that fruit can occasionally be superabundant, butit is often produced at low rates and in low quantities. Variationin fruit abundance results from several biotic selective pressures,including variation in the density, diversity, and reliabilityof potential dispersal agents. To judge from the size structure,dietary similarities, habitat preferences and foraging behaviorsof taxonomically-restricted guilds of frugivorous birds andmammals, members of these guilds have competed for food in thepast and must occasionally do so today. Unusual climatic conditionscan occasionally "upset" phenological patterns and can createfood shortages that promote competition among closely-relatedspecies of frugivores. Avian and mammalian frugivores, however,probably seldom compete with each other for food in present-daytropical ecosystems. A major reason for this is that many tropicalplants have evolved fruits that are attractive to only a limitedsubset of frugivores (e.g., only birds or only bats). Plantsapparently "perceive" qualitative differences in the dispersalservices of birds and mammals and attempt to attract membersof one group but not the other.     

Assessing Projection Bias in Consumers’ Food Preferences

The aim of this study is to test whether projection bias exists in consumers’ purchasing decisions for food products. To achieve our aim, we used a non-hypothetical experiment (i.e., experimental auction), where hungry and non-hungry participants were incentivized to reveal their willingness to pay (WTP). The results confirm the existence of projection bias when consumers made their decisions on food products. In particular, projection bias existed because currently hungry participants were willing to pay a higher price premium for cheeses than satiated ones, both in hungry and satiated future states. Moreover, participants overvalued the food product more when they were delivered in the future hungry condition than in the satiated one. Our study provides clear, quantitative and meaningful evidence of projection bias because our findings are based on economic valuation of food preferences. Indeed, the strength of this study is that findings are expressed in terms of willingness to pay which is an interpretable amount of money.     

Does Colour of the Food Attract Ants?

Milky white, brown, yellow and pink sugar grains along with normal sugar grains in equal number were offered to the ants at different sites, in the foraging ground of a garden locating at Garia, Kolkata, India to note the role of colouration of the food in food selection, if any. It is revealed that the ants Anoplolepis gracilipes procured all the supplied colour sugar grains from the offered sites between 1 and 43 min and the normal sugar grains between 1 and 38 min from the offered sites. Results of statistical analyses clearly indicate that the colour of the food has no role to attract the ants A. gracilipes in respect to procurement times of the sugar grains noted. This suggests that the colour of the food does not act as an attractant for the ants A. gracilipes in food selection.     

Hypothalamic eIF2α Signaling Regulates Food Intake

1. Download : Download full-size image

     

In Vitro Survey of α-Glucosidase Inhibitory Food Components

A survey of food components with α-glucosidase (AGH) inhibitory activity was conducted to identify a prophylactic effect for diabetes in food. Sardine muscle hydrolyzed by alkaline protease showed potent activity (IC₅₀ = 48.7mg/ml) as well as green and oolong teas (IC₅₀ = 11.1 and 11.3mg/ml, respectively). Furthermore, hydrolyzates prepared by various proteases gave differing AGH inhibitory activity. DEAE-Sephadex chromatography of the alkaline protease hydrolyzate eluted potent AGH inhibitors (IC₅₀ = 15.6mg/ml) with a 50 mm phosphate buffer (pH 7.0) containing 0.3 m NaCl, and their subsequent separation by HPLC in an ODS column showed that there were some inhibitors possessing primary amino groups. This indicates that they would have been high anionic and peptidic compounds.     

Disinfection in Food Processing – Efficacy Testing of Disinfectants

The key to effective cleaning and disinfection of food plants is the understanding of the type of the soil to be removed from the surfaces. An efficient cleaning and disinfection procedure consists of a sequence of rinses using good quality water with application of detergents and disinfectants. Disinfection is required in food plant operations, where wet surfaces provide favourable conditions for the growth of microbes. The efficacy of disinfectants is usually determined in suspensions, which do not mimic the growth conditions on surfaces where the agents are required to inactivate the microbes. Therefore, the suspension tests do not give adequate information and reliable carrier tests, which mimic surface growth, are needed. In developing a proposal for the testing of disinfectants on surfaces to an analytical standard, it is important to identify the major sources of variation in the procedure. In response to the need for a relatively realistic, simple and reliable test for disinfectant efficacy a method for culturing laboratory model biofilms has developed. The use of artificial biofilms i.e. biofilm-constructs inoculated with process contaminants in disinfectant testing can also be used for screening the activity of various disinfectants on biofilm cells. Both biofilm carrier tests showed clearly that the biofilm protects the microbes against the disinfectants. The chemical cleanliness is also essential in food plants. The total cleanliness of the process lines is mainly based on measuring the microbial load using culturing techniques. These results can give an incorrect picture of the total cleanliness, because the viable microbes do not grow when disinfectants are left on the surface. The luminescent bacteria light inhibition method offers a useful alternative for testing chemical residue left on surfaces after cleaning and disinfection operations.     

Somaclonal Variation in a Food Legume—Lathyrus sativus

Somaclones of Lathyrus sativus cv P-24 were obtained from leaf, internode and root derived callus cultures. These showed significantly decreased neurotoxin (ODAP) content up to 0.03% compared to that of parent cultivar P-24 (0.3%). The somaclones also showed higher seed yield than parent P24. In addition. somaclone Bio 1–22 showed significantly decreased time for flowering. Other heritable morphological variant features were leaf length, leaf breadth, internode length, flower colour, seed colour, 100 seed weight, neurotoxin content of leaves and red markings on the pods.     

Are Neglected Plants the Food for the Future?

Malnutrition, poor health, hunger, and even starvation are still the world's greatest challenges. Malnutrition is defined as deficiency of nutrition due to not ingesting the proper amounts of nutrients by simply not eating enough food and/or by consuming nutrient-poor food in respect to the daily nutritional requirements. Moreover, malnutrition and disease are closely associated and incidences of such diet-related diseases increase particularly in low- and middle-income states. While foods of animal origin are often unaffordable to low-income families, various neglected crops can offer an alternative source of micronutrients, vitamins, as well as health-promoting secondary plant metabolites. Therefore, agricultural and horticultural research should develop strategies not only to produce more food, but also to improve access to more nutritious food. In this context, one promising approach is to promote biodiversity in the dietary pattern of low-income people by getting access to nutritional as well as affordable food and providing recommendations for food selection and preparation. Worldwide, a multitude of various plant species are assigned to be consumed as grains, vegetables, and fruits, but only a limited number of these species are used as commercial cash crops. Consequently, numerous neglected and underutilized species offer the potential to diversify not only the human diet, but also increase food production levels, and, thus, enable more sustainable and resilient agro- and horti-food systems. To exploit the potential of neglected plant (NP) species, coordinated approaches on the local, regional, and international level have to be integrated that consequently demand the involvement of numerous multi-stakeholders. Thus, the objective of the present review is to evaluate whether NP species are important as “Future Food” for improving the nutritional status of humans as well as increasing resilience of agro- and horti-food systems.     

Soil Food Web Changes during Spontaneous Succession at Post Mining Sites: A Possible Ecosystem Engineering Effect on Food Web Organization?

Parameters characterizing the structure of the decomposer food web, biomass of the soil microflora (bacteria and fungi) and soil micro-, meso- and macrofauna were studied at 14 non-reclaimed 1– 41-year-old post-mining sites near the town of Sokolov (Czech Republic). These observations on the decomposer food webs were compared with knowledge of vegetation and soil microstructure development from previous studies. The amount of carbon entering the food web increased with succession age in a similar way as the total amount of C in food web biomass and the number of functional groups in the food web. Connectance did not show any significant changes with succession age, however. In early stages of the succession, the bacterial channel dominated the food web. Later on, in shrub-dominated stands, the fungal channel took over. Even later, in the forest stage, the bacterial channel prevailed again. The best predictor of fungal bacterial ratio is thickness of fermentation layer. We argue that these changes correspond with changes in topsoil microstructure driven by a combination of plant organic matter input and engineering effects of earthworms. In early stages, soil is alkaline, and a discontinuous litter layer on the soil surface promotes bacterial biomass growth, so the bacterial food web channel can dominate. Litter accumulation on the soil surface supports the development of the fungal channel. In older stages, earthworms arrive, mix litter into the mineral soil and form an organo-mineral topsoil, which is beneficial for bacteria and enhances the bacterial food web channel.     

Food or nesting place? Identifying factors limiting Wryneck populations

In recent decades, farmland bird populations have declined strongly as a consequence of agriculture intensification. Birds may have lost breeding sites, food supply or other crucial resources, with the role of multiple factors often remaining unclear. The ant-eating and cavity-breeding Wryneck (Jynx torquilla) may be limited by the availability of cavities, the number of ants or their accessibility. By comparing occupied and unoccupied breeding territories, we investigated the relative role of these factors in the decline of Wrynecks. We compared the characteristics of known Wryneck breeding territories (availability of breeding cavities, food abundance and ground vegetation structure) with randomly selected, fictitious territories (n = 154) in Western Switzerland. We also studied environmental factors that may affect ant nest density. The probability of territory occupancy strongly increased with both nestbox availability and ant abundance. In addition, this probability peaked around 50% of bare ground cover. Habitat types that harbour low ant abundance such as cropland and grassland were avoided. Ant nest density decreased with increasing amounts of bare ground, and it was particularly high in vineyards. Our results showed that breeding cavities, food availability and its accessibility all limit Wryneck distribution. The maintenance and restoration of ant rich grassland, interspersed with patches of bare ground and with hollow trees or dedicated nestboxes in the surroundings, are essential to preserve Wryneck populations. Such a habitat structure could be achieved even in intensively farmed habitats, such as in vineyards or fruit tree plantations.     

Isotopic Diversity Indices: How Sensitive to Food Web Structure?

Recently revisited, the concept of niche ecology has lead to the formalisation of functional and trophic niches using stable isotope ratios. Isotopic diversity indices (IDI) derived from a set of measures assessing the dispersion/distribution of points in the δ-space were recently suggested and increasingly used in the literature. However, three main critics emerge from the use of these IDI: 1) they fail to account for the isotopic sources overlap, 2) some indices are highly sensitive to the number of species and/or the presence of rare species, and 3) the lack of standardization prevents any spatial and temporal comparisons. Using simulations we investigated the ability of six commonly used IDI to discriminate among different trophic food web structures, with a focus on the first two critics. We tested the sensitivity of the IDI to five food web structures along a gradient of sources overlap, varying from two distinct food chains with differentiated sources to two superimposed food chains sharing two sources. For each of the food web structure we varied the number of species (from 10 to 100 species) and the type of species feeding behaviour (i.e. random or selective feeding). Values of IDI were generally larger in food webs with distinct basal sources and tended to decrease as the superimposition of the food chains increased. This was more pronounced when species displayed food preferences in comparison to food webs where species fed randomly on any prey. The number of species composing the food web also had strong effects on the metrics, including those that were supposedly less sensitive to small sample size. In all cases, computing IDI on food webs with low numbers of species always increases the uncertainty of the metrics. A threshold of ∼20 species was detected above which several metrics can be safely used.