Poor Food Source Research Articles

Saxitoxin-Producing Raphidiopsis raciborskii (Cyanobacteria) Constrains Daphnia Fitness and Feeding Rate despite High Nutritious Food Availability.

Changes in food quality can dramatically impair zooplankton fitness, especially in eutrophic water bodies where cyanobacteria are usually predominant. Cyanobacteria are considered a food with low nutritional value, and some species can produce bioactive secondary metabolites reported as toxic to zooplankton. Considering that cyanobacteria can limit the survival, growth and reproduction of zooplankton, we hypothesized that the dietary exposure of neotropical Daphnia species (D. laevis and D. gessneri) to saxitoxin-producing cyanobacteria impairs Daphnia feeding rates and fitness regardless of a high availability of nutritious algae. Life table and grazing assays were conducted with different diets: (1) without nutritional restriction, where neonates were fed with diets at a constant green algae biomass (as a nutritious food source), and an increasing cyanobacterial concentration (toxic and poor food source), and (2) with diets consisting of different proportions of green algae (nutritious) and cyanobacteria (poor food) at a total biomass 1.0 mg C L-1. In general, the presence of high proportions of cyanobacteria promoted a decrease in Daphnia somatic growth, reproduction and the intrinsic rate of population increase (r) in both diets with more pronounced effects in the nutritionally restricted diet (90% R. raciborskii). A two-way ANOVA revealed the significant effects of species/clone and treatments in both assays, with significant interaction between those factors only in the second assay. Regarding the grazing assay, only D. laevis was negatively affected by increased cyanobacterial proportions in the diet. In the life table assay with constant nutritious food, a reduction in the reproduction and the intrinsic rate of the population increase (r) of all species were observed. In conclusion, we found adverse effects of the toxic cyanobacterial strain R. raciborskii on Daphnia fitness, regardless of the constant amount of nutritious food available, proving the toxic effect of R. raciborskii and that the nutritional quality of the food has a greater influence on the fitness of these animals.

Food and Nutrient Consumption Patterns of Filipino Pregnant and Lactating Women Based on a Nationwide Survey

Due to the limited studies focusing on micronutrient intakes of pregnant and lactating women,and important dietary sources in the Philippines, this study aims to provide an insight into the food and nutrient consumption pattern of pregnant and lactating women. The objectives were to: [1] identify the food groups commonly consumed and dietary patterns of Filipino pregnant and lactating women; [2] describe the macro- and micronutrient intakes of these women; [3]assess the adequacy of these intakes against dietary references; and [4] identify important food sources of their energy and nutrient intakes. This study involved a cross-sectional secondary analysis of the data of 1,474 pregnant women and 4,571 lactating women covered in the 2018–2019 Expanded National Nutrition Surveys (ENNS). Food and beverage intakes were collected using a 24-h food recall method. Energy and nutrient intakes were calculated and analyzed in relation to the Philippine Dietary Reference Intakes (PDRI). Dishes predominantly consumed by pregnant and lactating women were comprised of rice and rice products, fish and products,and vegetables. Cereal consumption is higher, whereas there was a low consumption of meat,milk and dairy products, eggs, dried beans, nuts, and seeds, starchy roots and tubers, and fruits.The mean energy intakes of pregnant and lactating women were below the recommended energy intake (REI). The majority of pregnant (83.6%) and lactating (81.2%) had intakes below theestimated average requirement (EAR) for protein. Mean intakes of all micronutrients except niacin and phosphorous were below the EAR. Iron, calcium, vitamin C, and riboflavin intakes were furthest from the EAR. Less than 1% of pregnant and lactating women met the EAR for iron, whereas less than 10% met the EAR for vitamin A. Rice and rice products were the most important dietary sources of energy, protein, iron, thiamin, riboflavin, niacin, and phosphorus in the diet of pregnant and lactating women. The findings of this study reflect the low intakes of energy, protein, vitamins, and minerals due to poor dietary quality and food sources, thus increasing the risk of nutrient deficiency among Filipino pregnant and lactating women.

Both biotic and abiotic predictors explain significant variation in cyanobacteria biomass across lakes from temperate to subarctic zones

AbstractThe development of cyanobacteria blooms is of increasing concern in many lakes worldwide, and as a result, modeling their predictors is vital for understanding where and why they occur. In this study, we developed and analyzed a 640‐lake data set that spans Canada and 12 ecozones to identify the drivers of cyanobacteria biomass and of several key toxin‐ and bloom‐forming genera (Microcystis, Aphanizomenon, and Dolichospermum). The database consisted of an exhaustive list of potential predictors (n = 55), including water chemistry, land‐use, and zooplankton variables. We applied a series of empirical modeling approaches to identify significant predictors and thresholds (generalized linear and additive models, mixed effect regression trees), all while accounting for ecozone variability. Across all modeling approaches, and ecozones total phosphorus was identified as the most important predictor of total cyanobacterial and focal genera biomass. In addition, cyanobacteria across Canada showed significant associations with increasing dissolved organic and inorganic carbon, and several ions. Despite the widely held notion that cyanobacteria are often toxic and/or a poor food source for zooplankton, we found a positive relationship between cyanobacteria and zooplankton, particularly with daphnid and copepod biomass. Localized top‐down forces and evolutionary adaptations resulting from long‐term exposure in eutrophic lakes are among the possible explanations for this observed positive association. By considering a suite of complementary modeling approaches, we found that nonlinear models provided greater predictive power and the random ecozone effect was minor due to the overarching importance of local abiotic and biotic factors.

Juncus Bulbosus Tissue Nutrient Concentrations and Stoichiometry in Oligotrophic Ecosystems: Variability with Seasons, Growth Forms, Organs and Habitats.

Aquatic plant nutrient concentrations provide important information to characterise their role in nutrient retention and turnover in aquatic ecosystems. While large standing biomass of aquatic plants is typically found in nutrient-rich localities, it may also occur in oligotrophic ecosystems. Juncus bulbosus is able to form massive stands even in very nutrient-dilute waters. Here we show that this may be achieved by tissues with very high carbon-to-nutrient ratios combined with perennial (slow) growth and a poor food source for grazers inferred from plant stoichiometry and tissue nutrient thresholds. We also show that the C, N, P and C:N:P stoichiometric ratios of Juncus bulbosus vary with the time of year, habitats (lakes versus rivers) and organs (roots versus shoots). We found no differences between growth forms (notably in P, inferred as the most limiting nutrient) corresponding to small and large plant stands. The mass development of J. bulbosus requires C, N and P, whatever the ecosystem (lake or river), and not just CO2 and NH4, as suggested in previous studies. Since macrophytes inhabiting oligotrophic aquatic ecosystems are dominated by isoetids (perennial plants with a high root/shoot ratio), attention should be paid to quantifying the role of roots in aquatic plant stoichiometry, nutrient turnover and nutrient retention.

From Symbionts to Societies: How Wood Resources Have Shaped Insect Sociality

Sociality has independently arisen in several wood-dwelling insect lineages. Despite this seemingly important ecological trait, little attention has been devoted to understanding how the properties of decaying logs as nest or food resources favor the evolution of cooperative social groups. In this review, we evaluate the current literature on wood-dwelling social insects to identify the key features of wood habitats that has led to the repeated evolution of social behavior. We emphasize important roles of both the structural properties of wood as well as the microbial symbionts and pathogens with which wood-dwelling social insects co-evolved. Wood-tissue is structural resilient, and thus provided an enclosed, defensible nest site for early wood-feeding insect groups. This resilience enabled the long-term persistence of family groups, and was likely a key feature in the transition towards more complex eusocial societies. The dense structure of wood, however, also makes it a nutritionally poor food source. Insects that both live and feed on this resource developed complex mutualisms with prokaryote and fungal symbionts to digest this resource. Parental care likely evolved to ensure adequate nutrition for offspring in this environment by allowing parents to both provision and transfer microbial symbionts to offspring. Pathogenic microbes are also abundant in nests constructed in wood-tissue, and social adaptations such as allogrooming and nest maintenance may have evolved in response to microbial invaders. In general, the dynamic relationship between insects, microbes, and the wood-tissue that they inhabit was a critical component in the evolution of sociality in this habitat.

Impact of nutritional stress on the honeybee colony health

Honeybees Apis mellifera are important pollinators of wild plants and commercial crops. For more than a decade, high percentages of honeybee colony losses have been reported worldwide. Nutritional stress due to habitat depletion, infection by different pests and pathogens and pesticide exposure has been proposed as the major causes. In this study we analyzed how nutritional stress affects colony strength and health. Two groups of colonies were set in a Eucalyptus grandis plantation at the beginning of the flowering period (autumn), replicating a natural scenario with a nutritionally poor food source. While both groups of colonies had access to the pollen available in this plantation, one was supplemented with a polyfloral pollen patty during the entire flowering period. In the short-term, colonies under nutritional stress (which consumed mainly E. grandis pollen) showed higher infection level with Nosema spp. and lower brood and adult bee population, compared to supplemented colonies. On the other hand, these supplemented colonies showed higher infection level with RNA viruses although infection levels were low compared to countries were viral infections have negative impacts. Nutritional stress also had long-term colony effects, because bee population did not recover in spring, as in supplemented colonies did. In conclusion, nutritional stress and Nosema spp. infection had a severe impact on colony strength with consequences in both short and long-term.

Development and Application of a Low-Volume Flow System for Solution-State in Vivo NMR.

In vivo nuclear magnetic resonance (NMR) spectroscopy is a particularly powerful technique, since it allows samples to be analyzed in their natural, unaltered state, criteria paramount for living organisms. In this study, a novel continuous low-volume flow system, suitable for in vivo NMR metabolomics studies, is demonstrated. The system allows improved locking, shimming, and water suppression, as well as allowing the use of trace amounts of expensive toxic contaminants or low volumes of precious natural environmental samples as stressors. The use of a double pump design with a sump slurry pump return allows algal food suspensions to be continually supplied without the need for filters, eliminating the possibility of clogging and leaks. Using the flow system, the living organism can be kept alive without stress indefinitely. To evaluate the feasibility and applicability of the flow system, changes in the metabolite profile of 13C enriched Daphnia magna over a 24-h period are compared when feeding laboratory food vs exposing them to a natural algal bloom sample. Clear metabolic changes are observed over a range of metabolites including carbohydrates, lipids, amino acids, and a nucleotide demonstrating in vivo NMR as a powerful tool to monitor environmental stress. The particular bloom used here was low in microcystins, and the metabolic stress impacts are consistent with the bloom being a poor food source forcing the Daphnia to utilize their own energy reserves.

Sedimentary and egg-bank DNA from 3 European lakes reveal concurrent changes in the composition and diversity of cyanobacterial and Daphnia communities

Eutrophication generally favours the growth of cyanobacteria over eukaryotic green algae in freshwater lakes. Cyanobacteria constitute a poor food source for the waterflea Daphnia, an important primary consumer of phytoplankton in lakes. While it is known that some Daphnia species are adapted to eutrophic conditions and can cope with cyanobacteria in their diet, it is less known whether cyanobacterial community composition can influence Daphnia population structure in lakes. We studied the variation in genetic diversity of Daphnia resting eggs and cyanobacterial DNA preserved in sediment cores from three European lakes impacted by eutrophication. Our retrospective analysis confirms that D. galeata invaded the two pre-alpine lakes around the middle of the twentieth century, hybridized with and became dominant over D. longispina. This coincides with the presence in all lakes and the increase in the proportion of colonial and filamentous cyanobacteria in the pre-alpine lakes. The recent re-oligotrophication of the lakes did not reverse the cyanobacterial and Daphnia assemblages to their pre-eutrophication composition and genetic structure, suggesting that both changed irreversibly due to anthropogenic influence on the ecosystems. Genetic analyses applied to lake sedimentary archives have the potential to unveil how different compartments of the food web covary in a changing environment.

Private information alone can trigger trapping of ant colonies in local feeding optima.

Ant colonies are famous for using trail pheromones to make collective decisions. Trail pheromone systems are characterised by positive feedback, which results in rapid collective decision making. However, in an iconic experiment, ants were shown to become 'trapped' in exploiting a poor food source, if it was discovered earlier. This has conventionally been explained by the established pheromone trail becoming too strong for new trails to compete. However, many social insects have a well-developed memory, and private information often overrules conflicting social information. Thus, route memory could also explain this collective 'trapping' effect. Here, we disentangled the effects of social and private information in two 'trapping' experiments: one in which ants were presented with a good and a poor food source, and one in which ants were presented with a long and a short path to the same food source. We found that private information is sufficient to trigger trapping in selecting the poorer of two food sources, and may be sufficient to cause it altogether. Memories did not trigger trapping in the shortest path experiment, probably because sufficiently detailed memories did not form. The fact that collective decisions can be triggered by private information alone may require other collective patterns previously attributed solely to social information use to be reconsidered.

Climate Effects on High Latitude Daphnia via Food Quality and Thresholds.

Climate change is proceeding rapidly at high northern latitudes and may have a variety of direct and indirect effects on aquatic food webs. One predicted effect is the potential shift in phytoplankton community structure towards increased cyanobacterial abundance. Given that cyanobacteria are known to be a nutritionally poor food source, we hypothesized that such a shift would reduce the efficiency of feeding and growth of northern zooplankton. To test this hypothesis, we first isolated a clone of Daphnia pulex from a permafrost thaw pond in subarctic Québec, and confirmed that it was triploid but otherwise genetically similar to a diploid, reference clone of the same species isolated from a freshwater pond in southern Québec. We used a controlled flow-through system to investigate the direct effect of temperature and indirect effect of subarctic picocyanobacteria (Synechococcus) on threshold food concentrations and growth rate of the high latitude clone. We also compared the direct effect of temperature on both Daphnia clones feeding on eukaryotic picoplankton (Nannochloropsis). The high latitude clone had a significantly lower food threshold for growth than the temperate clone at both 18 and 26°C, implying adaptation to lower food availability even under warmer conditions. Polyunsaturated fatty acids were present in the picoeukaryote but not the cyanobacterium, confirming the large difference in food quality. The food threshold for growth of the high latitude Daphnia was 3.7 (18°C) to 4.2 (26°C) times higher when fed Synechococcus versus Nannochloropsis, and there was also a significant negative effect of increased temperature and cyanobacterial food on zooplankton fatty acid content and composition. The combined effect of temperature and food quality on the performance of the high latitude Daphnia was greater than their effects added separately, further indicating the potentially strong indirect effects of climate warming on aquatic food web processes.

Dealing with the presence of the ciliate Euplotes sp. in cultures of the copepod Acartia tonsa

Ciliates in live feed cultures can be a pest that lower production yields. This could dramatically affect the management and success of copepod cultures. In this study, we investigated the effect of the ciliate Euplotes sp. on egg production, specific egg production and egg hatching success of Acartia tonsa fed with Rhodomonas salina. We found that at a concentration of 2 cells ml−1, Euplotes sp. had no effect on the production and hatching success of eggs but increased/decreased the mortality/quality of non-subitaneous eggs. Euplotes sp. had a good fatty acid profile containing high proportion of unsaturated fatty acids, but the amount of fatty acids compared to their carbon weight was very low and, therefore, it was considered as a poor food source. We propose a short-term interruption of food supply to copepod cultures in order to mitigate bloom formation of ciliates. This will force copepods to feed on them actively as prey and therefore decrease their long-term negative effects.

Plasticity of collective behavior in a nomadic early spring folivore

Collective behavior in the forest tent caterpillar (Malacosoma disstria) meets the thermal constraints of being an early spring folivore, but introduces other constraints in food choice. These are minimized by state-dependent, inter-individual, and ontogenetic variations in responses to social cues. Forest tent caterpillars use pheromone trails and tactile communication among colony members to stay together during foraging. At the group level, these rules lead to cohesive synchronized collective nomadic foraging, in which the colony travels en masse between feeding and resting sites. This paper proposes that synchronized collective locomotion prevents individuals from becoming separated from the colony and hence permits them to reap the advantages of group-living, notably collective basking to increase their body temperature above ambient and collective defense against natural enemies. However, this cohesive behavior also implies conservative foraging, and colonies can become trapped on poor food sources. High fidelity to pheromone trails leads to strong amplification of an initial choice, such that colonies seldom abandon the first food source contacted, even if a better one is nearby. The risk of this trapping is modulated both by consistent inter-individual variations in exploratory behavior and by inner state. Colonies consisting of active-phenotype or protein-deprived individuals that explore more-off trails exhibit greater collective flexibility in foraging. An ontogenetic shift toward more independent movement occurs as caterpillars grow. This leads to colony break-up as the season advances. Selection pressures facing older caterpillars favor solitary living more than in the earlier instars. Caterpillars respond to this predictably changing environment by altering their behavioral rules as they grow.

Limited feeding on bacteria by two intertidal benthic copepod species as revealed by trophic biomarkers

Harpacticoids can discriminate between biofilms of different bacterial strains. We investigated whether assimilation of bacteria is selective and whether harpacticoids select for the most nutritional bacteria. We specifically focused on the role of bacterial characteristics in copepod food selection. Trophic biomarkers (stable isotopes, fatty acids) were used to test selective assimilation of three bacteria by the harpacticoids Platychelipus littoralis and Delavalia palustris, all isolated from a salt marsh. The bacteria Gramella sp., Jannaschia sp. and Photobacterium sp. with contrasting ribosomal protein and fatty acid contents were (13)C-labelled and offered in a food patch choice experiment with monospecific and combination treatments (single and two strains per microcosm respectively). Low assimilation of bacterial carbon and lack of significant fatty acid transfer proved that bacteria were a poor food source for the harpacticoids. Assimilation was copepod species-specific and bacteria strain-specific (preference for Photobacterium). However, only a low degree of selective feeding occurred; it can partly be explained by bacterial extracellular metabolites rather than by biochemical content and densities. Finally, the energetic cost of differential bacterivory resulted in a negative fatty acid balance for Platychelipus, while Delavalia showed an improved fatty acid profile and thus a positive response to the low-quality bacterial food.

Collective choice of a higher-protein food source by gregarious caterpillars occurs through differences in exploration

Amplification, whereby an individual’s probability of exhibiting a particular behavior increases with the number of conspecifics already performing this behavior, enhances the accuracy and speed of collective decision-making by gregarious animals. However, too strong amplification can lead to the potentially suboptimal selection of the first patch encountered. In eusocial insects (e.g., ants, bees), active recruitment and differential signaling provide a mechanism to avoid this type of collective trap. We use the nomadic gregarious caterpillar Malacosoma disstria to test whether the higher quality of two food sources can be consistently selected in the absence of this type of mechanism. We show that, in this species, neither active recruitment nor differential signaling occur, but that collective choice of the higher quality of two food sources is instead made through differences in exploration. These caterpillars lack flexibility in trail laying, but a reduction in trail following behavior enables them to abandon a poor food source and initiate exploration, forming new trails that are followed by the group. The propensity to leave marked territory and initiate exploration varies with food quality, and increases with decreasing protein content in the food. Indeed, although previous work showed that caterpillar groups can become trapped on a poor-quality protein-only food, we show that they abandon a similarly poor-quality low-protein food and relocate to a more nutritionally appropriate one. This is consistent with previous work showing that protein deprivation increases exploratory behavior in individual caterpillars and suggests that food quality can influence collective foraging in ways more complex than a simple distinction between high and low quality sources. Furthermore, the latency to initiate exploration also decreases with increasing group size, as the probability that a single individual initiates exploration increases. Contrary to previously studied species, amplification is not modulated according to source quality in this species; instead it is through effects on exploration that food protein content and caterpillar group size influence collective decision-making.

Nematodes and protozoa affect plants differently, depending on soil nutrient status

We grew plants in soil amended with either finely ground (<0.2 mm) or larger pieces (4 × 5 mm2) of maize leaves. Finely ground material will be mineralized faster; hence nitrogen is released faster in the soil. We inoculated the soil with the plant growth inhibiting bacterium Arthrobacter BEM463, a relatively poor food source for bacterial feeders, and the plant growth promoter Sphingopyxis BEM760 which is a good food source. Protozoa and nematodes were introduced separately or in combination. In soil with larger maize leaf pieces (low turnover, slow nitrogen release), bacterial feeders generally increased plant nitrogen uptake and growth. In systems with finely ground material (high turnover, fast nitrogen release), plants hardly benefited from presence of grazers; bacterial mineralization activity alone probably provided enough N for the plants. The harmful Arthrobacter thrived better when grazed by protozoa than when grazed by nematodes, probably because the selective protozoa could avoid it, which resulted in reduced plant performance. We suggest that bacterial feeders generally increase plant performance when nutrients are limited. At high nutrient availability, however, bacterial feeders promote grazer resistant bacteria, and, if these bacteria are harmful to plants, the net effect of bacterial feeders on plant growth can be negative.

Gammarus-Microbial Interactions: A Review

Gammarusspp. are typically classified as shredders under the functional feeding group classification. In the wild and in the laboratory,Gammarusspp. will often shred leaves, breaking them down into finer organic matter fractions. However, leaf litter is a poor quality food source (i.e., high C : N and C : P ratios) and very little leaf material is assimilated by shredders. In freshwater habitats leaf litter is colonized rapidly (within ∼1-2 weeks) by aquatic fungi and bacteria, making the leaves more palatable and nutritious to consumers. Several studies have shown thatGammarusspp. show preference for conditioned leaves over nonconditioned leaves and certain fungal species to others. Furthermore,Gammarusspp. show increased survival and growth rates when fed conditioned leaves compared to non-conditioned leaves. Thus,Gammarusspp. appear to rely on the microbial biofilm associated with leaf detritus as a source of carbon and/or essential nutrients. Also,Gammarusspp. can have both positive and negative effects on the microbial communities on which they fed, making them an important component of the microbial loop in aquatic ecosystems.

Knowledge and Usage Patterns of Folic Acid amongst Physician Assistant Students at the University of Texas Medical Branch at Galveston.

Physician Assistant (PA) students are educated that 400 micrograms (μg) of daily folic acid (FA) is a vital component of prenatal care to reduce fetal development abnormalities. Studies have shown that higher education level is correlative with the use of daily FA in women of reproductive age. The objective of this study was to assess PA students' knowledge of the physiologic implications of FA supplementation, the recommended dosage and intake regimen, and how having this knowledge impacted their behavior. A knowledge-based questionnaire was given to 59 first year female PA students and 39 third year female PA students at the University of Texas Medical Branch at Galveston (UTMB). Overall FA use amongst female UTMB PA students is 66.3%. Furthermore, 40% of the third year students consumed 400 μg of FA daily as opposed to 7.8% of the first year students. One-hundred percent of the third year students knew that FA deficiency caused NTDs, and 86.4% of the first year students recognized this causation. There was poor compliance for following the United States Preventative Services Task Force (USPSTF) recommended FA regimen amongst students in the UTMB PA program. The results in our study were comparable to the previous publications, finding that the majority of women in both our study and the general population acknowledged the importance of FA supplementation. BACKGROUND AND SIGNIFICANCE Folate, Vitamin B9, is a naturally occurring water-soluble vitamin. Foods containing folate include leafy green vegetables, oranges, legumes, and liver (Brown et al., 1997). Due to the poor bioavailability and limited food sources of folate, a synthetic form was developed: FA (Winkels, Brouwer, Siebelink, Katan, & Verhoef, 2007). The U.S. Public Health Service issued a recommendation in 1992 stating “all women of reproductive age in the U.S., capable of becoming pregnant, should consume 400 μg of FA daily to reduce the risk of having a pregnancy affected by [neural tube defect] NTD” (Prue, Flores, Panissidi, & Lira, 2008). The Food and Drug Administration (FDA) utilized this recommendation in 1998, and mandated that all enriched grains be fortified with FA (CDC, 2007). In 2005 the Dietary Guidelines for Americans (DGA) made an effort to inform the general population about these new recommendations, and advocated women consume 400 μg of FA daily in multivitamin or supplement form in addition to the FA provided by enriched foods (Cena et al., 2008). In May 2009, the USPSTF recommended “all women planning or capable of pregnancy take a daily supplement containing 400 μg – 800 μg of FA” (U.S. Preventative Services Task Force, 2009). The importance of FA is annually recognized by the Department of Health and Human Services, the Centers for Disease Control, and the National Birth Defects Prevention Network during January’s National Birth Defects Prevention Month (Center for Disease Control and Prevention, 2007). Lifetime healthcare costs for children suffering from spina bifida can exceed two million dollars per child for medical and surgical care of the individual (Spina Bifida Association, 2009). It is important for women of reproductive age to be proactive regarding their health and the health of a potential

The evolutionary ecology of detritus feeding in the larvae of freshwater Diptera

Detritus (dead organic matter), largely of terrestrial origin, is superabundant in inland waters but because of its indigestible nature, would appear to be a poor food source for animals. Yet this unpromising material is widely used as food and indeed can be viewed as a defining characteristic of the freshwater environment. We here explore the relationships among animals, detritus and its associated micro-organism decomposers, taking a functional approach. We pose questions about interrelationships and attempt to arrive at new insights by disentangling them from an adaptive point of view. To do this we have been careful in selecting the habitats for detailed consideration. Rain pools on rock surfaces in tropical Africa and pools on peat moorland in the UK were chosen. Both examples have a relatively simple community structure and hence offer the prospect of achieving our aim. As model organisms for study we focus principally on the aquatic stages of selected holometabolous insects; that is, selected genera of the universally common midges, Ceratopogonidae and Chironomidae. We approach these case studies from an evolutionary ecology perspective and see detritus as a simple template upon which a beautiful complex of adaptations can evolve.

Termite digestomes as sources for novel lignocellulases

AbstractFor most animals, lignocellulose is a nutritionally poor food source that is highly resistant to enteric degradation. Termites, however, have the unique ability to digest lignocellulose with high efficiency, often using it as a sole food source. Another interesting aspect of termite biology is their symbiotic associations with prokaryotic and eukaryotic gut symbionts. Termite symbionts contribute to lignocellulose digestion efficiency, but by no means are they responsible for 100% of lignocellulose digestion in the termite gut. The termite digestome can be defined as the pool of genes, both termite and symbiont, that contribute to lignocellulose depolymerization and digestion, as well as simple sugar fermentation, nutrient transport, and nutrient assimilation. A central goal of termite digestomics research is to define/understand the relative contributions of termite and symbiont gene products to collaborative lignocellulose digestion. While efficient microbial cellulases have already been identified and are presently being used in industrial applications, efficient and inexpensive pre‐treatments for lignin and hemicellulose depolymerization are not yet well developed. In this respect, termite digestomics has already offered significant insights, and can continue to identify relevant enzymes, as well as reveal how to optimally combine and utilize these enzymes for maximum synergy. The topics covered in this review are as follows: lignocellulose structure with emphasis on its potential for depolymerization by termite and gut endosymbiont‐derived digestive enzymes; termite biology and ecology from the perspectives of termite nutrition, gut physiology, and lignocellulose digestion; and trends identified through recent termite digestomics research. © 2008 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Meta-analysis of cyanobacterial effects on zooplankton population growth rate: species-specific responses

We analyzed a large data set of laboratory experiments to examine the effects of cyanobacteria containing or lacking intracellular toxic metabolites and of different morphology on zooplankton population growth rates across multiple genera and species of cladocerans, rotifers and cyanobacteria. Twenty-one of the 29 zooplankton species maintained positive growth rates when fed a diet containing cyanobacteria even though cyanobacteria were a poor food source for half of the zooplankton species tested relative to a diet containing only green algae and/or flagellates. Differences among zooplankton species could not be explained by grazer species body lengths, even when experiments were restricted to those that used only filamentous cyanobacteria. Single-celled cyanobacteria were more detrimental to a larger number of zooplankton species compared to filamentous or chroococcoid colonial cyanobacteria. We also found no clear effect of putative cyanobacterial toxins on the growth of seven zooplankton species but we did detect a negative effect for the largest cladoceran species, Daphnia magna. Among the cyanobacterial genera, Microcystis had the largest negative effect on zooplankton population growth and there was no consistent difference between M. aeruginosa strains that produced microcystins and those that did not. Our results highlight the large variation in species-specific responses of zooplankton to cyanobacteria. Although cyanobacterial toxicity and mechanical interference may be important drivers in particular cyanobacteria-zooplankton interactions, we did not find general support for these mechanisms through the use of this meta-analysis.