农业景观生物多样性下降和农业环境计划效果

由于欧盟共同农业政策(CAP)的实施,农业集约化加速发展,导致了农田中大量典型的野生动植物物种种群数量锐减.1992年,欧盟向其成员国推出了农业环境条例2078/92,其目的是通过农业环境计划帮助其成员国扭转这种变化.我们所面临的问题是这些计划的执行对于农田景观生物多样性的恢复是否充分有效?以往对农业环境计划效果的研究多以英国和荷兰的农田鸟类为中心.就目前来看,其作用有很大的局限性.这些计划需要继续评价和改进以促进受到EU前农业政策影响的农田生物多样性的恢复.     

A link between eumelanism and calcium physiology in the barn owl

In many animals, melanin-based coloration is strongly heritable and is largely insensitive to the environment and body condition. According to the handicap principle, such a trait may not reveal individual quality because the production of different melanin-based colorations often entails similar costs. However, a recent study showed that the production of eumelanin pigments requires relatively large amounts of calcium, potentially implying that melanin-based coloration is associated with physiological processes requiring calcium. If this is the case, eumelanism may be traded-off against other metabolic processes that require the same elements. We used a correlative approach to examine, for the first time, this proposition in the barn owl, a species in which individuals vary in the amount, size, and blackness of eumelanic spots. For this purpose, we measured calcium concentration in the left humerus of 85 dead owls. Results showed that the humeri of heavily spotted individuals had a higher concentration of calcium. This suggests either that plumage spottiness signals the ability to absorb calcium from the diet for both eumelanin production and storage in bones, or that lightly spotted individuals use more calcium for metabolic processes at the expense of calcium storage in bones. Our study supports the idea that eumelanin-based coloration is associated with a number of physiological processes requiring calcium.     

Behavioral genomics of honeybee foraging and nest defense

The honeybee has been the most important insect species for study of social behavior. The recently released draft genomic sequence for the bee will accelerate honeybee behavioral genetics. Although we lack sufficient tools to manipulate this genome easily, quantitative trait loci (QTLs) that influence natural variation in behavior have been identified and tested for their effects on correlated behavioral traits. We review what is known about the genetics and physiology of two behavioral traits in honeybees, foraging specialization (pollen versus nectar), and defensive behavior, and present evidence that map-based cloning of genes is more feasible in the bee than in other metazoans. We also present bioinformatic analyses of candidate genes within QTL confidence intervals (CIs). The high recombination rate of the bee made it possible to narrow the search to regions containing only 17–61 predicted peptides for each QTL, although CIs covered large genetic distances. Knowledge of correlated behavioral traits, comparative bioinformatics, and expression assays facilitated evaluation of candidate genes. An overrepresentation of genes involved in ovarian development and insulin-like signaling components within pollen foraging QTL regions suggests that an ancestral reproductive gene network was co-opted during the evolution of foraging specialization. The major QTL influencing defensive/aggressive behavior contains orthologs of genes involved in central nervous system activity and neurogenesis. Candidates at the other two defensive-behavior QTLs include modulators of sensory signaling (Am5HT ₇ serotonin receptor, AmArr4 arrestin, and GABA-B-R1 receptor). These studies are the first step in linking natural variation in honeybee social behavior to the identification of underlying genes.     

Worker honey bee pheromone regulation of foraging ontogeny

The evolution of sociality has configured communication chemicals, called primer pheromones, which play key roles in regulating the organization of social life. Primer pheromones exert relatively slow effects that fundamentally alter developmental, physiological, and neural systems. Here, I demonstrate how substances extracted from the surface of foraging and young pre-foraging worker bees regulated age at onset of foraging, a developmental process. Hexane-extractable compounds washed from foraging workers increased foraging age compared with controls, whereas extracts of young pre-foraging workers decreased foraging age. This represents the first known direct demonstration of primer pheromone activity derived from adult worker bees.     

Individual lifetime pollen and nectar foraging preferences in bumble bees

Foraging specialization plays an important role in the ability of social insects to efficiently allocate labor. However, relatively little is known about the degree to which individual bumble bees specialize on collecting nectar or pollen, when such preferences manifest, and if individuals can alter their foraging preferences in response to changes in the colony workforce. Using Bombus impatiens, we monitored all foraging visits made by every bee in multiple colonies and showed that individual foragers exhibit consistent lifetime foraging preferences. Based upon the distribution of foraging preferences, we defined three forager types (pollen specialists, nectar specialists, and generalists). In unmanipulated colonies, 16–36?% of individuals specialized (≥90?% of visits) on nectar or pollen only. On its first day of foraging, an individual’s foraging choices (nectar only, pollen only, or nectar and pollen) significantly predicted its lifetime foraging preferences. Foragers that only collected pollen on their first day of foraging made 1.61- to 1.67-fold more lifetime pollen foraging visits (as a proportion of total trips) than foragers that only collected nectar on their first foraging day. Foragers were significantly larger than bees that stayed only in the nest. We also determined the effect of removing pollen specialists at early (brood present) or later (brood absent) stages in colony life. These results suggest that generalists can alter their foraging preferences in response to the loss of a small subset of foragers. Thus, bumble bees exhibit individual lifetime foraging preferences that are established early in life, but generalists may be able to adapt to colony needs.     

Tandem carrying,a new foraging strategy in ants: description,function, and adaptive significance relative to other described foraging strategies

An important aspect of social insect biology lies in the expression of collective foraging strategies developed to exploit food. In ants, four main types of foraging strategies are typically recognized based on the intensity of recruitment and the importance of chemical communication. Here, we describe a new type of foraging strategy, “tandem carrying”, which is also one of the most simple recruitment strategies, observed in the Ponerinae species Pachycondyla chinensis. Within this strategy, workers are directly carried individually and then released on the food resource by a successful scout. We demonstrate that this recruitment is context dependent and based on the type of food discovered and can be quickly adjusted as food quality changes. We did not detect trail marking by tandem-carrying workers. We conclude by discussing the importance of tandem carrying in an evolutionary context relative to other modes of recruitment in foraging and nest emigration.     

The interaction of temperature and sucrose concentration on foraging preferences in bumblebees

Several authors have found that flowers that are warmer than their surrounding environment have an advantage in attracting pollinators. Bumblebees will forage preferentially on warmer flowers, even if equal nutritional reward is available in cooler flowers. This raises the question of whether warmth and sucrose concentration are processed independently by bees, or whether sweetness detectors respond to higher sugar concentration as well as higher temperature. We find that bumblebees can use lower temperature as a cue to higher sucrose reward, showing that bees appear to process the two parameters strictly independently. Moreover, we demonstrate that sucrose concentration takes precedence over warmth, so that when there is a difference in sucrose concentration, bees will typically choose the sweeter feeder, even if the less sweet feeder is several degrees warmer.     

Social learning of an associative foraging task in zebrafish

The zebrafish (Danio rerio) is increasingly becoming an important model species for studies on the genetic and neural mechanisms controlling behaviour and cognition. Here, we utilized a conditioned place preference (CPP) paradigm to study social learning in zebrafish. We tested whether social interactions with conditioned demonstrators enhance the ability of focal naïve individuals to learn an associative foraging task. We found that the presence of conditioned demonstrators improved focal fish foraging behaviour through the process of social transmission, whereas the presence of inexperienced demonstrators interfered with the learning of the control focal fish. Our results indicate that zebrafish use social learning for finding food and that this CPP paradigm is an efficient assay to study social learning and memory in zebrafish.     

Chemical compounds of the foraging recruitment pheromone in bumblebees

When the frenzied and irregular food-recruitment dances of bumblebees were first discovered, it was thought that they might represent an evolutionary prototype to the honeybee waggle dance. It later emerged that the primary function of the bumblebee dance was the distribution of an alerting pheromone. Here, we identify the chemical compounds of the bumblebee recruitment pheromone and their behaviour effects. The presence of two monoterpenes and one sesquiterpene (eucalyptol, ocimene and farnesol) in the nest airspace and in the tergal glands increases strongly during foraging. Of these, eucalyptol has the strongest recruitment effect when a bee nest is experimentally exposed to it. Since honeybees use terpenes for marking food sources rather than recruiting foragers inside the nest, this suggests independent evolutionary roots of food recruitment in these two groups of bees.     

Social familiarity modulates group living and foraging behaviour of juvenile predatory mites

Environmental stressors during early life may have persistent consequences for phenotypic development and fitness. In group-living species, an important stressor during juvenile development is the presence and familiarity status of conspecific individuals. To alleviate intraspecific conflicts during juvenile development, many animals evolved the ability to discriminate familiar and unfamiliar individuals based on prior association and use this ability to preferentially associate with familiar individuals. Assuming that familiar neighbours require less attention than unfamiliar ones, as predicted by limited attention theory, assorting with familiar individuals should increase the efficiency in other tasks. We assessed the influence of social familiarity on within-group association behaviour, development and foraging of juvenile life stages of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. The observed groups consisted either of mixed-age familiar and unfamiliar juvenile mites or of age-synchronized familiar or unfamiliar juvenile mites or of pairs of familiar or unfamiliar larvae. Overall, familiar mites preferentially grouped together and foraged more efficiently, i.e. needed less prey at similar developmental speed and body size at maturity, than unfamiliar mites. Preferential association of familiar mites was also apparent in the inter-exuviae distances. Social familiarity was established by imprinting in the larval stage, was not cancelled or overridden by later conspecific contacts and persisted into adulthood. Life stage had an effect on grouping with larvae being closer together than nymphal stages. Ultimately, optimized foraging during the developmental phase may relax within-group competition, enhance current and future food supply needed for optimal development and optimize patch exploitation and leaving under limited food.     

White certificates and domestic offset schemes: possible synergies

Next to energy efficiency, in the context of GHG reductions, additional policy mechanisms to the incumbent EU Emissions Trading scheme (EU ETS) are discussed. Such is the case of Non-ETS Domestic Offset (DO) schemes, which can reduce CO₂-eq.emissions in the non-ETS sectors and trade these as CO₂ credits on the ETS market. Taking into account that the EU’s “Linking Directive” (EC 2004) creates the conditions to use credits generated by emission reduction projects certified by the UN Framework Convention on Climate Change Kyoto Protocol (KP) within the EU ETS market, in this paper we employ the institutional analysis method of interactions in order to provide insight of a combined White Certificates (WhC) and DOs cheme. Special attention is paid to the parameters that seem to hamper harmonization of WhC and DO. Aim of this paper is to discuss whether smart market- based instruments, such as WhC, can be complementary to the effectiveness of mechanisms fostering energy efficiency such as DOs projects and vice versa. In this respect, the potential combined scheme is assessed (ex-ante) with the help of standard criteria that refer to the triptych energy, environment & society. Given the outcome of the study made, it is fair to say that such a DO/WhC combined scheme could be selected if the additionality concern is to minimize short term social costs of reaching a certain goal. However recent information and research conducted so far cannot yet uphold an ambition that a WhC/DO scheme of this kind could also drive technical change, keep consumer costs down and be equitable.     

Life cycle assessment of MSW-to-energy schemes in Thailand

Life cycle assessment was performed to evaluate environmental impacts of two municipal solid waste (MSW) to energy schemes currently practiced in Thailand: incineration and anaerobic digestion. Potential impacts such as global warming, acidification, stratospheric ozone depletion, and photo-oxidant formation were avoided due to net electricity production and also fertilizer production as by-products from the anaerobic digestion scheme. In addition, the anaerobic digestion resulted in the higher net energy output compared to the incineration scheme. However, the incineration had less potential impact for nutrient enrichment. The LCA results were also useful in determining where the improvements could be made for both the schemes. In order to adopt a sustainable waste management system elsewhere in the country, decision makers may need to consider a combination of techniques, or an integrated method of management. LCA could serve as an invaluable tool for such an analysis.     

Scarce water resources and priority irrigation schemes from agronomic crops

Global environmental change places unavoidable pressure on water resources and agronomic crop production systems. Irrigation development is a credible measure to alleviate the challenge of food safety under water shortages, but it needs sufficient basis. The aim of this study is to address the problem of balancing water scarcity with food requirements, which are the key components of water security in regions with population growth. Marginal water productivity (MWP) indices for irrigation water performance and productivity evaluation were established in the current study. Based on the analysis of the regional water-crop relationship and spatial differences of MWP in China, the priorities for developing irrigation areas in different types of regions are discussed in this study. The results show that high MWPs are mainly in semi-arid regions with precipitation (P) between 500 and 1000 mm, while low MWPs mostly occur in areas with P more than 1000 and less than 500 mm. The significance and spatial distribution patterns of MWP are different than those of conventional irrigation water use efficiency evaluation indices, so its role cannot be replaced for the real production capacity of irrigation water evaluation. The strategies for global environmental change adaptation suggested in this study are taking MWP for irrigation water productivity evaluation and the priority irrigation schemes for agronomic crop determination; increasing MWP by means of irrigation efficiency and crop variety improvement worldwide; and raising global food production through the expansion of irrigation area in the regions hold high MWP and abundant water resources.

     

Winter bird use of seed-rich habitats in agri-environment schemes

To assess the effectiveness of over-winter seed provision by agri-environment schemes, bird use of patches of seed-bearing crops was compared with that of other seed-rich habitats on 53 farms in eastern Scotland over three winters. Seed-bearing crops were the most frequently selected habitat, and held 28% of birds of the 10 species recorded. Outside schemes, cereal stubble was the most selected habitat and held 44% of birds. For nine species, seed-bearing crops were used by more birds than expected from the area of crop available in at least one winter, and five species were more likely to occur in first-winter patches, reflecting a greater abundance of cereal grain than in second-winter patches. For cereal grain specialists such as buntings, sowing cereal-based crops annually would ensure that grain is available in each winter, whilst either a 1-year or a 2-year crop would be appropriate for finches that favour oilseeds, and species with a more generalist diet.