Low-quality Food Research Articles

Facilitation of clear-water conditions in shallow lakes by macrophytes: differences between charophyte and angiosperm dominance

A number of mechanisms result in a feedback between water clarity and macrophytes and, consequently, the occurrence of alternative stable states in shallow lakes. We hypothesize that bottom-up mechanisms and interactions within the benthic food web are more important in a charophyte-dominated clear-water state, while top-down mechanism and interactions in the planktonic food web prevail at angiosperm dominance. Charophytes, which dominate at lower nutrient concentrations and develop higher densities than most angiosperms, can have a higher influence on sedimentation, resuspension, and water column nutrients. During dominance of dense submerged vegetation like charophytes, zooplankton can be hampered by low food quality and quantity and by high predation pressure from juvenile fish, which in turn are favoured by the high refuge potential of this vegetation. Grazing pressure from zooplankton on phytoplankton can therefore be low in charophytes, but the main feedback in angiosperm-dominated ecosystems. Charophytes offer a higher surface than most angiosperms to periphyton, which favors benthic invertebrates. These support macrophytes by grazing periphyton and constitute a central link in a trophic cascade from fish to periphyton and macrophytes. To test these hypotheses, more experiments and field measurements comparing the effect of charophytes and angiosperms on water clarity are needed.

Altered Primary Production During Mass-Extinction Events

The Big Five mass-extinction events are characterized by dramatic changes in primary producers. Initial disturbance to primary producers is usually followed by a succession of pioneers that represent qualitative and quantitative changes in standing crops of land plants and/or phytoplankton. On land, a transient collapse of arborescent (tree-bearing) vegetation and the rapid spread of a pioneer vegetation dominated by ferns and fern allies characterizes the Permian/Triassic (P/T), Triassic/Jurassic (T/J), and Cretaceous/Paleogene (K/Pg) mass-extinction events. The availability of low-quality food, such as herbaceous low-growing plants, likely played a role in triggering secondary extinctions of herbivores (reptiles, insects). Furthermore, malformation of acritarchs, pollen, and spores during the end-Ordovician, end-Devonian, P/T and T/J extinctions also suggests primary producers were of lesser quality. More importantly, changes in vegetation drove important increases in weathering and erosion leading to elevated nutrient transfer from the continents to the oceans. In the marine realm, the end-Ordovician, end-Devonian, end-Permian, and end-Triassic extinction events are all followed by periods of high primary production, which is reflected in the widespread deposition of black shales. Due to their small size, low nutritional quality, and possible toxicity, the abundance of picoplankton, such as prasinophytes, acritarchs, as well as bacterioplankton (cyanobacteria and green sulfur bacteria) may have been additional factors in delaying ecosystem recovery.

The reaction of European lobster larvae (Homarus gammarus) to different quality food: effects of ontogenetic shifts and pre-feeding history

Young larval stages of many organisms represent bottlenecks in the life-history of many species. The high mortality commonly observed in, for example, decapod larvae has often been linked to poor nutrition, with most studies focussing on food quantity. Here, we focus instead on the effects of quality and have investigated its effects on the nutritional condition of lobster larvae. We established a tri-trophic food chain consisting of the cryptophyte Rhodomonas salina, the calanoid copepod Acartia tonsa and larvae of the European lobster Homarus gammarus. In a set of experiments, we manipulated the C:N:P stoichiometry of the primary producers, and accordingly those of the primary consumer. In a first experiment, R. salina was grown under N- and P-limitation and the nutrient content of the algae was manipulated by addition of the limiting nutrient to create a food quality gradient. In a second experiment, the effect on lobster larvae of long- and short-term exposure to food of varying quality during ontogenetic development was investigated. The condition of the lobster larvae was negatively affected even by subtle N- and P-nutrient limitations of the algae. Furthermore, younger lobster larvae were more vulnerable to nutrient limitation than older ones, suggesting an ontogenetic shift in the capacity of lobster larvae to cope with low quality food. The results presented here might have substantial consequences for the survival of lobster larvae in the field, as, in the light of future climate change and re-oligotrophication of the North Sea, lobster larvae might face marked changes in temperature and nutrient conditions, thus significantly altering their condition and growth.

Temporal niche switching by grizzly bears but not American black bears in Yellowstone National Park

Grizzly bears (Ursus arctos) have been reported as either nocturnal or diurnal in various studies, but have not been known to switch between the 2 times unless disturbed by humans. Black bears (Ursus americanus) are almost solely diurnal in studies unless human influences occur. Because human disturbance is often difficult to control, the relative temporal niche of both species remains ill-defined. Thus, the present study examined bears in Yellowstone National Park (Wyoming) where hunting does not occur, human activities are relatively benign, and bear species are sympatric to determine if niche occupancy was a stable feature of the species. Onset of activity was anticipatory of both sunrise or morning civil twilight (illumination sufficient for human vision) for individuals of either species. The peak hour of activity in black bears was consistently midday, but fluctuated in grizzly bears from midday during early spring, late summer, and fall to evening during late spring and early summer. Black bears did not temporally avoid the times when the more dominant grizzly bears were active. Mean activity levels were higher for male black bears than for both male and female grizzly bears. Together, results suggest that the foraging needs of black bears necessitate ingestion of less-digestible, lower-quality foods requiring longer foraging time during daytime hours, whereas grizzly bears adapt their diet to seasonally available food sources, necessitating greater temporal flexibility.

Shift in Black Rhinoceros Diet in the Presence of Elephant: Evidence for Competition?

In African large herbivore assemblages, megaherbivores dominate the biomass and utilise the greatest share of available resources. Consequently, they are considered a separate trophic guild that structures the food niches of coexisting large herbivores. However, there exists little empirical evidence on how food resources are shared within this guild, and none for direct competition for food between megaherbivores. Using the histological analysis of faeces, we explore this phenomenon for African elephant Loxodonta africana and black rhinoceros Diceros bicornis in the Addo Elephant National Park, South Africa, where the accumulated impacts of elephant have reduced browse availability. Despite being unable to generalise beyond our study sites, our observations support the predictions of competition theory (as opposed to optimality theory) by showing (1) a clear seasonal separation in resource use between these megaherbivores that increased as resource availability declined, and (2) rhinoceros changed their selectivity in the absence of elephant (using an adjacent site) by expanding and shifting their diet along the grass-browse continuum, and in relation to availability. Although black rhinoceros are generally considered strict browsers, the most significant shift in diet occurred as rhinoceros increased their preferences for grasses in the presence of elephant. We speculate that the lack of specialised grazing adaptations may increase foraging costs in rhinoceros, through reduced harvest- and handling-efficiencies of grasses. In the short-term, this may be off-set by an enhanced tolerance for low quality food and by seasonally mobilising fat reserves; however, the long-term fitness consequences require further study. Our data suggest that managing elephant at high densities may compromise the foraging opportunities of coexisting browsers. This may be particularly important in small, fenced areas and overlapping preferred habitats where impacts intensify.

Food Intake Changes in Relation to Food Quality in the Neotropical Frugivorous BatSturnira ludovici

If nutritional elements of food and the consumer's ability to use them can determine an animal diet, we can expect that differences in digestive capacity between animals reflect their dietary breadth. Diet diversity in Neotropical frugivorous bats is based on core plant taxa that present different nutritional compositions and qualities. Sturnira bats eat fruits with high sugar concentration, while Artibeus species eat fruits with lower sugar content. In this study we investigated the intake sugar response of Sturnira ludovici and compare it with the intake response reported for Artibeus jamaicensis. Our results show that S. ludovici was unable to achieve compensatory feeding, ingesting twice the energy when feeding on the most concentrated solution with respect to the more diluted one. This finding suggests the existence of a physiological constraint limiting energy intake when this species feeds on low quality food. Intake response slope value for S. ludovici was lower than the one reported for A. jamaicensis, indicating that S. ludovici is less suited than A. jamaicensis to feed on food with low nutrient content. The role that a physiological limitation could have on the food intake of S. ludovici, and the ecological implications of our findings are discussed.

The turbidity front as a habitat for Acartia tonsa (Copepoda) in the Río de la Plata, Argentina-Uruguay

Acartia tonsa is one of the most abundant copepod species in estuaries worldwide. In the Río de la Plata, its highest densities appear to occur in an area of low quality food (detritus): the turbidity front (TF). The objective of this study was to understand how trophic and oceanographic drivers contribute to the high densities of A. tonsa in the Río de la Plata TF. The patterns of spatial distribution and density of this species were analyzed in relation to oceanographic and biological attributes of the system. The egg production rate (EPR) in the TF was evaluated as a measure of fitness, and a stable isotope analysis indicated the possible sources of organic matter in the species' diet. This study confirmed that the highest observed densities of A. tonsa were mostly associated with the TF, where high suspended matter and low Chl-a occur. Immediately offshore from the TF, decreased copepod densities and the maximum Chl-a values were found. Females close to the estuarine turbidity maximum (ETM) had a lower EPR than those closer to the high Chl-a concentrations. Within the TF, A. tonsa apparently fed on detritus close to the ETM and phytoplankton close to the edge of the TF. The report includes a discussion of how retention processes, two layered flow and the life history strategy of A. tonsa could be contributing to the development of high densities (more than 10,000indm−3) of this species in the inner estuarine zone, despite the poor quality of food available for development in that area. A. tonsa can live and prosper in areas with high turbidity and low chlorophyll concentrations. This trait exemplifies the plasticity of this species and helps explain why it is a key species in many worldwide estuaries.

Food access, social safety nets, and social stigma among low‐income families in Massachusetts

Social safety nets like SNAP, WIC, and fuel assistance can alleviate food insecurity and improve household resources. They may not prevent health consequences of food insecurity unless they promote purchase and consumption of healthful foods. Social stigma around use of benefits can prevent vulnerable families from utilizing benefits, which may further complicate food insecurity. We analyzed focus group transcripts (6 focus groups, 21 participants) with low‐income, largely food insecure individuals in Massachusetts to assess use of social safety nets and related social stigma. We used directed content analysis to examine pre‐identified themes and to identify new themes. Pre‐ identified themes included the use of SNAP and WIC to extend resources and stigmatization of the use of social safety nets by the members of the community. New themes were utilization of fuel assistance to free up resources, saving SNAP for special and healthy foods, stigmatization of low cost foods by children, stigma within the community for resource allocation of benefit users, and self‐stigmatization. Different stigma associated with the use of social benefits and purchase of low cost foods might prevent low‐income individuals from utilizing. In this context, allocation of certain benefits, such as SNAP, to purchase low quality foods might lead to health complication in the future.Funding source: USDA‐CSREES #H994

Flexibility in collective decision-making by ant colonies: Tracking food across space and time

Deciding which of many available resources to exploit is a problem faced by a range of decentralized biological systems. For example, ants are able to choose between food sources that vary in quality using a chemical trail. This communication system characterized by a strong positive feedback allows a rapid transfer of information and the selection of the best food source. This is true in static environment, where a single, unchanging solution exists. In dynamic environments however such recruitment often ‘lock’ groups into suboptimal decisions, preventing a response to changes in available resources. Here, we investigate decision-making in a dynamic environment for the greenhead ants (Rhytidoponera metallica) which use a non-chemical recruitment. To experimentally test our study species’ ability to adapt to changes in their foraging environment, we offered three feeders that changed in quality. At any given time, only one feeder provided high quality food, while the others provided low quality food. Every two hours, the quality of the feeders changed such that the previously high quality feeder became a low quality feeder, and vice versa. We showed that ants were able to track changes in food quality across space and time. By coupling behavioral observations to computer simulations, we demonstrate that selection of food sources relies uniquely on a retention effect of feeding individuals on newcomers without comparison between available opportunities. The elegance of these parsimonious foraging systems is that the collective decision arises from the perception of conspecifics without the need for a leader having a synoptic overall view of the situation and knowing all the available options.

When good neighbors don't need fences: Temporal landscape partitioning among baboon social groups.

Intraspecific competition is a key factor shaping space-use strategies and movement decisions in many species, yet how and when neighbors utilize shared areas while exhibiting active avoidance of one another is largely unknown. Here we investigated temporal landscape partitioning in a population of wild baboons (Papio cynocephalus). We used global positioning system (GPS) collars to synchronously record the hourly locations of 5 baboon social groups for ~900 days, and we used behavioral, demographic, and life history data to measure factors affecting use of overlap areas. Annual home ranges of neighboring groups overlapped substantially, as predicted (baboons are considered non-territorial), but home ranges overlapped less when space use was assessed over shorter time scales. Moreover, neighboring groups were in close spatial proximity to one another on fewer days than predicted by a null model, suggesting an avoidance-based spacing pattern. At all time scales examined (monthly, biweekly, and weekly), time spent in overlap areas was greater during time periods when groups fed on evenly dispersed, low-quality foods. The percent of fertile females in social groups was negatively correlated with time spent in overlap areas only during weekly time intervals. This suggests that broad temporal changes in ecological resources are a major predictor of how intensively overlap areas are used, and groups modify these ecologically driven spacing patterns at short time scales based on female reproductive status. Together these findings offer insight into the economics of territoriality by highlighting the dynamics of spacing patterns at differing time scales.

Tips for Integrating Land and Wildlife Management: Deer in Ranchlands

In addition to having generally low-quality foods, ranchlands often have a low diversity of food sources, further reducing the quality of habitat for deer. Ranchland management for deer should therefore focus on providing a diversity of abundant, high-quality foods. This 2-page fact sheet provides some deer habitat improvement tips that focus primarily on raising the quality of deer forage but that also will help you grow better cover by improving plant diversity and productivity. Written by William M. Giuliano, John M. Olson, and Cailey Thomas, and published by the UF Department of Wildlife Ecology and Conservation, January 2013. 
 http://edis.ifas.ufl.edu/uw375

Absorption efficiency of mussels Mytilus edulis and Mytilus galloprovincialis cultured under Integrated Multi-Trophic Aquaculture conditions in the Bay of Fundy (Canada) and Ría Ares-Betanzos (Spain)

Integrated Multi-Trophic Aquaculture (IMTA) is a recycling concept in which waste nutrient discharges from high trophic levels become an additional energetic input for extractive organisms such as bivalves. The aim of this study was to measure the seston levels and absorption efficiency of mussels reared in the proximity of fish net-pens. The absorption efficiency of mussels Mytilus galloprovincialis and Mytilus edulis cultured at sites adjacent to red sea bream (Pagellus bogaraveo) and salmon (Salmo salar) cages was assessed on site, using natural seston diets and compared with mussels reared distant from the cages in the Ría de Ares-Betanzos (Galicia, N.W. Spain) and the Bay of Fundy (S.W. New Brunswick, Canada), respectively. Total particulate matter and the organic and the inorganic fractions of the seston were measured simultaneously. Seston parameters were generally similar at the mussel sites close to the fish cages and at the reference sites. However, significantly higher particulate inorganic matter coupled with lower food quality (seston organic content) observed at the sites close to the fish cages suggested occasional sediment resuspension events in the Ría de Ares-Betanzos and the Bay of Fundy. Owing to the reduced food quality, 20% lower absorption efficiency was measured for mussels in the proximity to the cages during the resuspension events. No significant differences in absorption efficiency were detected between the fish cages and the reference sites outside the resuspension events. Consequently, differences in absorption efficiency were attributed to natural variations in seston organic content, and absorption increased with increasing food quality. The results showed no evidence of increased organic content of the seston resulting from proximity to the fish-farm. It was concluded that proximity of cultured mussels to the fish cages did not result in an enhancement of the absorption efficiency.

Fruiting and flushing phenology in Asian tropical and temperate forests: implications for primate ecology

In order to understand the ecological adaptations of primates to survive in temperate forests, we need to know the general patterns of plant phenology in temperate and tropical forests. Comparative analyses have been employed to investigate general trends in the seasonality and abundance of fruit and young leaves in tropical and temperate forests. Previous studies have shown that (1) fruit fall biomass in temperate forest is lower than in tropical forest, (2) non-fleshy species, in particular acorns, comprise the majority of the fruit biomass in temperate forest, (3) the duration of the fruiting season is shorter in temperate forest, and (4) the fruiting peak occurs in autumn in most temperate forests. Through our comparative analyses of the fruiting and flushing phenology between Asian temperate and tropical forests, we revealed that (1) fruiting is more annually periodic (the pattern in oneyear is similar to that seen in the next year) in temperate forest in terms of the number of fruiting species or trees, (2) there is no consistent difference in interannual variations in fruiting between temperate and tropical forests, although some oak-dominated temperate forests exhibit extremely large interannual variations in fruiting, (3) the timing of the flushing peak is predictable (in spring and early summer), and (4) the duration of the flushing season is shorter. The flushing season in temperate forests (17-28% of that in tropical forests) was quite limited, even compared to the fruiting season (68%). These results imply that temperate primates need to survive a long period of scarcity of young leaves and fruits, but the timing is predictable. Therefore, a dependence on low-quality foods, such as mature leaves, buds, bark, and lichens, would be indispensable for temperate primates. Due to the high predictability of the timing of fruiting and flushing in temperate forests, fat accumulation during the fruit-abundant period and fat metabolization during the subsequent fruit-scarce period can be an effective strategy to survive the lean period (winter).

Daphnia's dilemma of adjusting carbon budgets when facing limitations by food quantity and the essential organic compound cholesterol

We studied the carbon (C) metabolism in Daphnia when the amount of C (food quantity) and/or the content of biochemical nutrients (food quality) was limiting. Growth performances and C budgets of Daphnia magna (assimilation, faeces egestion, excretion and respiration measured by [(14)C]-tracing) were analysed when animals were raised on different food quantities and concentrations of cholesterol, an essential biochemical food compound. Cholesterol is of special interest because it not only acts as limiting nutrient but also contributes to the overall C pool of the animals. As the tissue cholesterol concentration in Daphnia is quite low, we hypothesized the selective exclusion of cholesterol from C budgeting and tested this using radiolabelled cholesterol. Somatic growth rates of D. magna were highest at high quantity and quality and were reduced to a moderate value if either the food quantity or the cholesterol concentration was low. Growth was lowest at low food quantity and quality. The measurements of C budgets revealed high regulative response to low food quality at high food quantity only. Here, low dietary cholesterol caused bulk C assimilation efficiency (AE) to decrease and assimilated (excess) C to be increasingly respired. Additionally, Daphnia enhanced efficient adjustment of C budgets when facing cholesterol limitation by (1) increasing the AE of the cholesterol itself and (2) not changing cholesterol respiration, which was still not detectable. In contrast, at low food quantity, Daphnia is unable to adjust for low food quality, emphasizing that food limitation could overrule food quality effects.

Responsive Regulation and Application of Grading Systems in the Food Safety Regulatory Regimes of Developing Countries

The traditional tit-for-tat philosophy in the food safety regulatory regime in most developing countries has been proven ineffective in most cases. Rather, starting with persuasion, advice, and then escalating to more severe punishments for the continuing non-compliance as suggested in the responsive regulation by Ayres and Braithwaite has been proved more effective in the food safety regulatory regime of some jurisdictions. Responsive regulation aims to increase among corporations. So, if a corporation shows responsibility, it should be rewarded, and if a corporation shows irresponsibility, it should be reprimanded (if necessary). There is no logic in seeing and treating every manufacturer the same, considering their regular compliance or regular non-compliance with regulation. Furthermore, in a free market economy, food manufacturers have to compete everyday with their counterparts in regard to safety and standards. Considering these situations, current research suggests that the grading system can be introduced into the food safety regulatory regime of developing countries. Once the food manufacturers are rewarded for their compliance by upgrading their current grade, they can use this reward for advertising, which will help their business flourish. Conversely, if any manufacturer shows irresponsibility and continuously produces unsafe and low quality food, it can be degraded from an upper to lower grade. However, even the lowest graded manufacturer will have to maintain the minimum standard of safety required by the state regulations. This concept can be called responsibility ensures upgrading, irresponsibility risks downgrading. In short, this article suggests that the responsive regulation can be applied by moderating with grading system in the food safety regulatory regime of the developing countries. A qualitative research method has been used in this research, and extensive literature has been analysed.

The roles of food quality and sex in chimpanzee sharing behavior (Pan troglodytes)

Both wild and captive chimpanzees (Pan troglodytes) share food with non-relatives. Researchers have proposed several hypotheses to explain this behavior, including ‘food for sex’, ‘food for grooming or agonistic support’, and ‘sharing under pressure’. We examined food sharing in two captive groups of socially-housed chimpanzees. In contrast to previous captive studies, which only examined transfers of low-quality foods, we conducted seven trials with high-quality food and seven with low-quality food for each group to directly compare transfers of different food qualities. We recorded how male chimpanzees shared food, including active transfers, passive transfers, and co-feeding. We also noted all instances of copulations, female estrous states, benign attempts to access food (termed ‘perseverance’), and aggressive attempts (termed ‘harassment’) to examine whether any of these factors influenced food sharing. Male food possessors shared at the same rate in both food quality conditions, but seemingly for different reasons, indicating that food quality may affect the exchange of social benefits in chimpanzees. In the low-quality condition, there was an interaction with rank and perseverance: while low- and middle-ranking females received more food the more they persevered, high-ranking females received more food without perseverance and gained relatively little benefit from persevering. In the high-quality condition, there was an interaction between copulations and perseverance: females who copulated with the male food possessor received more food during that trial with less perseverance. Non-copulating females received more transfers the more they persevered. This result was only observed in the short-term — copulations over the previous year were not correlated with food transfers. Further, the copulations observed here were unusual for these chimpanzees in that they were not confined to peak fertility, suggesting a non-conceptive function for copulations in chimpanzees. Copulations in this study may have functioned to reduce tension and increase short-term tolerance, allowing females better access to food.

The Role of Sexual Selection and Conflict in Mediating Among-Population Variation in Mating Strategies and Sexually Dimorphic Traits in Sepsis punctum

The black scavenger fly Sepsis punctum exhibits striking among-population variation in the direction and magnitude of sexual size dimorphism, modification to the male forelimb and pre-copulatory behaviour. In some populations, male-biased sexual size dimorphism is observed; in other, less dimorphic, populations males court prior to mating. Such variation in reproductive traits is of interest to evolutionary biologists because it has the potential to limit gene flow among populations, contributing to speciation. Here, we investigate whether large male body size and modified forefemur are associated with higher male mating success within populations, whether these traits are associated with higher mating success among populations, and if these traits carry viability costs that could constrain their response to sexual selection. Flies from five distinct populations were reared at high or low food, generating high and low quality males. The expression of body size, forelimb morphology and courtship rate were each greater at high food, but high food males experienced higher mating success or reduced latency to first copulation in only one of the populations. Among populations, overall mating success increased with the degree of male-bias in overall body size and forelimb modification, suggesting that these traits have evolved as a means of increasing male mating rate. The increased mating success observed in large-male populations raises the question of why variation in magnitude of dimorphism persists among populations. One reason may be that costs of producing a large size constrain the evolution of ever-larger males. We found no evidence that juvenile mortality under food stress was greater for large-male populations, but development time was considerably longer and may represent an important constraint in an ephemeral and competitive growth environment.

Insect personality depends on environmental conditions

Increasing evidence has accumulated within the last decade that individuals of different animal species show consistent behavior both across various contexts and through time, that is, they do have personality. However, little is known in how far the environment an individual is facing may influence the personality of insects, whereas it is well established that the environment can have profound influences on performance parameters. The development of personality may be closely linked to different expectations in future fitness leading to contrasting life-history strategies. We investigated in how far the environmental food conditions experienced during lifetime influence the life-history and shape the personality of the mustard leaf beetle, Phaedon cochleariae, a pest of crucifers. Beetles reared on low-quality food developed slower and gained lower body masses than insects reared on high-quality food. By performing behavioral tests analogous to vertebrate assays repeatedly during adult life, we identified 3 personality dimensions, boldness, activity, and nontargeted explorativeness. Comparing food-dependent differences of the personality dimensions with state-dependent differences of the expected future prospects, we found that beetles feeding low-quality food were bolder, thereby potentially increasing their capabilities to succeed in foraging. In contrast, animals feeding high-quality food were more active. Changes in boldness may be highly adaptive to increase future reproductive output, whereas activity is likely constrained by the energy uptake. Our results demonstrate that the environment does not only affect life-history traits but has also a consistent impact on an individual’s behavior, which is likely highly adaptive.

Substrate-dependent bacterivory by intertidal benthic copepods

The trophic importance of bacteria to harpacticoid copepods in intertidal areas remains poorly understood, and so do the mechanisms of bacterial feeding. It is, for instance, unclear whether harpacticoids directly target bacterial cells or merely co-ingest them with substrates to which bacterial cells may be attached. Here, we investigate bacterial uptake and substrate requirement for four mud intertidal species (Microarthridion littorale, Platychelipus littoralis, Delavalia palustris and Nannopus palustris) by means of 13C-labeled bacteria and biomarker fatty acids (FA). Bacterial uptake strongly depended on grazing on a primary food source but bacterial ingestion rates were low, and no clear indication of copepods directly targeting bacteria was found. Delavalia was the only species that accumulated bacteria-derived FA and gained in polyunsaturated FA (PUFA) probably through bioconversion of bacteria-derived FA. In general, however, our results suggest that bacteria represent a relatively minor and low-quality food for intertidal harpacticoid copepods.

Obesity management: what brings success?

The upward trend in obesity prevalence across regions and continents is a worldwide concern. Today a majority of the world's population live in a country where being overweight or obese causes more deaths than being underweight. Only a portion of those qualifying for treatment will get the health care they need. Still, a minor weight loss of 5-10% seems to be sufficient to provide a clinically significant health benefit in terms of risk factors for cardiovascular disease and diabetes. Diet, exercise and behavior modifications remain the current cornerstones of obesity treatment. Weight-loss drugs play a minor role. Drugs which were available and reasonably effective have been withdrawn because of side effects. The fact that the 'old' well known, but pretty unexciting tools remain the basic armamentarium causes understandable concern and disappointment among both patients and therapists. Hence, bariatric surgery has increasingly been recognized and developed, as it offers substantial weight loss and prolonged weight control. The present review highlights the conventional tools to counter obesity, lifestyle modification, pharmacotherapy and bariatric surgery, including some of the barriers to successful weight loss: (1) unrealistic expectations of success; (2) high attrition rates; (3) cultural norms of self-acceptance in terms of weight and beliefs of fat being healthy; (4) neighborhood attributes such as a lack of well-stocked supermarkets and rather the presence of convenience stores with low-quality foods; and (5) the perception of the neighborhood as less safe and with low walkability. Prevention is the obvious key. Cost-effective societal interventions such as a tax on unhealthy food and beverages, front-of-pack traffic light nutrition labeling and prohibition of advertising of junk food and beverages to children are also discussed.