A Swedish comment on ‘review: the availability of life-cycle studies in Sweden’

The International Journal of Life Cycle Assessment -     

Evidence that implicit assumptions of ‘no evolution’ of disease vectors in changing environments can be violated on a rapid timescale

Projected impacts of climate change on vector-borne disease dynamics must consider many variables relevant to hosts, vectors and pathogens, including how altered environmental characteristics might affect the spatial distributions of vector species. However, many predictive models for vector distributions consider their habitat requirements to be fixed over relevant time-scales, when they may actually be capable of rapid evolutionary change and even adaptation. We examine the genetic signature of a spatial expansion by an invasive vector into locations with novel temperature conditions compared to its native range as a proxy for how existing vector populations may respond to temporally changing habitat. Specifically, we compare invasions into different climate ranges and characterize the importance of selection from the invaded habitat. We demonstrate that vector species can exhibit evolutionary responses (altered allelic frequencies) to a temperature gradient in as little as 7–10 years even in the presence of high gene flow, and further, that this response varies depending on the strength of selection. We interpret these findings in the context of climate change predictions for vector populations and emphasize the importance of incorporating vector evolution into models of future vector-borne disease dynamics.     

A comment on ‘ethnic discrimination in employment and housing’

This article investigates Los Angeles employers' attitudes towards African American and immigrant Latino low-skill workers. Using 145 in-depth interviews of employers in four industries, I find that a central concern of employers of low-skill jobs is control at the workplace, and employers consequently seek workers whom they perceive as manageable and pliable. As such, the most salient component of employers' attitudes towards African American and immigrant Latino low-skill workers is their perception that the manageability and pliability of workers vary by race, nativity and gender. I also link employers' micro-level attitudes to broader societal level ideologies about race and opportunity. I find that employers' attitudes were embedded within an ideology of individualism, as exemplified by the idea of the 'American Dream', and reflected the growing belief that race-based claims are illegitimate.     

A comment on ‘colonialism and ethnicity’

Self‐reported incidence of racial discrimination was investigated among four Asian‐American groups to explore their magnitude and the ways of coping with the discrimination episodes. The samples showed that among the two modes of coping ‐ problem‐focused or emotion‐focused coping ‐ a majority of Asian Americans has utilized the latter. Reasons of adopting these coping strategies were further explored for their determinants. Intergroup differences in ethnicity, education, gender and cultural values were found to exert influences on the ways of coping with racial discrimination among Asian Americans.     

A Re-Interpretation of the ‘Two-child Norm’ in Post-Transitional Demographic Systems: Fertility Intentions in Taiwan

Taiwan currently has one of the lowest fertility rates in the world, leading to projections of rapid population ageing and decline. In common with other territories in Pacific Asia, policies designed to support childbearing have recently been introduced. Some optimism for the future success of these policies has been drawn from the fact that the ‘ideal’ number of children stated in Taiwanese surveys is over two. In this way, Taiwan appears to fit the ‘two-child norm’ model identified for Europe and North America. Furthermore, this feature has led commentators to state that Taiwan is not in a ‘low fertility trap’–where positive feedback mechanisms emanating from the normalisation of small families, slow economic growth and ageing/declining population mean attempts to increase fertility become ever less likely to succeed. Using a recent national representative survey, and arguing that ‘intentions’ are a more reliable guide to understanding the circumstances of family formation, this paper explores fertility intentions in Taiwan with a special focus on women at parity one and parity two. This will form the first full-length examination of fertility intentions in Taiwan published in English and one of the few studies of Pacific Asia that reports a micro-level analysis. We argue that using intentions should provide a better ‘barometer’ of attitudes towards childbearing in Taiwan, and that through micro-level analysis, we can better identify the predictors of intentions that could, in turn, provide useful clues both for projections as well as shaping policy responses. While we found some evidence for a ‘two-child norm’ among childless women, this could be an unrealistic ideal. This is supported by the fact that a majority of women with one child do not intend to have another.     

Official statement of the Japan Monkey Centre on the ‘Shimokita incident’

The Japan Monkey Centre issued the following official statement concerning the aerial spraying of herbicide which was carried out at the end of June on the Shimokita Peninsula. It invites all who are interested in the research of nature to understand and support its aim for the conservation of wild Japanese monkeys and the protection of nature from artificial destruction. Copies of the statement (in Japanese) have been sent to a number of inland individuals and organizations concerned.     

‘Merry's Ears’—dispersal of fruits and seeds

Remarkable advances in the treatment of cataract have been made in recent years. Can we teach the eye well enough for these to be understood and appreciated by our students?

After receiving treatment for cataract by intraocular lens implant, the author found out as much as possible about this remarkable operation. Before describing the most recent developments and latest technology, the nature of cataract is discussed together with a brief outline of older methods of treatment. The question is addressed as to whether high-school biology can or should provide sufficient knowledge for pupils to understand this relatively simple defect and appreciate the latest complex remedies. Consideration is given to the possible development of new teaching aids from surgical research materials, for example, introducing pupils to the eye through recent advances in surgery, and so starting them off with the latest applications instead of the conventional ‘naming of parts’.     

Complexity in the eutrophication–harmful algal bloom relationship,with comment on the importance of grazing

This article seeks to guide the conceptual development and field application of the eutrophication–HAB hypothesis. After considering the evidence for this hypothesis, the importance of exogenous nutrients as a chemical habitat conditioner and the “family” of nutrient regulated effects that occur are discussed. The various definitions of eutrophication are applied; the conceptual ambiguity over how to perceive eutrophication, and the need to view eutrophication as a process and not as an ecological state are considered. The habitat irradiance-nutrient-flushing gradient regulates the bloom potential in response to exogenous nutrients. There is an apparent species-specific paradox within the eutrophication–HAB hypothesis related to the phycotoxin synthesis–nutrient relationship. Two nutrient–toxin relationships occur: toxin biosynthesis during nutrient sufficiency, and biosynthesis that requires a nutrient limitation. HAB events can be just as much nutrient depletion events as nutrient stimulated events, and whether the former develops depends upon the specific cellular toxicity–nutrient relationship of the bloom species. The importance of grazing in bloom regulation is highlighted. HABs and red tides generally should be viewed as blooms that are regulated by coupled nutrient-grazer processes – nutrient stimulation alone is inadequate, even when exogenous nutrients are not a factor. In assessing the eutrophication–HAB relationship, the collective grazing behavior of the micro-zooplankton, herbivorous copepods, filter feeding benthos, benthic larvae and, when present, omnivorous nekton must be considered. The importance of grazing in the bloom behavior of HAB species is illustrated using field and experimental data during a 5-month brown tide in Narragansett Bay. A cascade in grazing pressure regulated this bloom, with the initial collapse and then restoration of grazing pressure progressing through 7 stages of collective grazing pressure by micro-zooplankton, herbivorous copepods, benthic larvae, benthic filter feeders, and lytic virus infection.     

The ‘division of labour’ model of eye evolution

The ‘division of labour’ model of eye evolution is elaborated here. We propose that the evolution of complex, multicellular animal eyes started from a single, multi-functional cell type that existed in metazoan ancestors. This ancient cell type had at least three functions: light detection via a photoreceptive organelle, light shading by means of pigment granules and steering through locomotor cilia. Located around the circumference of swimming ciliated zooplankton larvae, these ancient cells were able to mediate phototaxis in the absence of a nervous system. This precursor then diversified, by cell-type functional segregation, into sister cell types that specialized in different subfunctions, evolving into separate photoreceptor cells, shading pigment cells (SPCs) or ciliated locomotor cells. Photoreceptor sensory cells and ciliated locomotor cells remained interconnected by newly evolving axons, giving rise to an early axonal circuit. In some evolutionary lines, residual functions prevailed in the specialized cell types that mirror the ancient multi-functionality, for instance, SPCs expressing an opsin as well as possessing rhabdomer-like microvilli, vestigial cilia and an axon. Functional segregation of cell types in eye evolution also explains the emergence of more elaborate photosensory–motor axonal circuits, with interneurons relaying the visual information.     

A ‘Goldilocks’ hypothesis for dispersal of biological control agents

The rate at which biological control agents disperse from release sites has important implications for their establishment and spread. Low rates of dispersal can yield spread that is too slow and may necessitate redistribution efforts for importation biological control and a high density of release sites for augmentation. Low dispersal rates may also lead to inbreeding at the site of release. On the other hand, high rates of dispersal can lead to Allee effects at the leading edge of the invasion front, potentially reducing the likelihood of establishment. Given these disadvantages associated with both low and high dispersal rates, we argue that intermediate rates of dispersal are likely to maximize the probability of establishment and appropriate spread for biological control agents released in the context of either importation or augmentative biological control. We consider this putative relationship a ‘Goldilocks hypothesis’ since it posits an optimum at intermediate values. In this review paper we begin by discussing the rationale for the Goldilocks hypothesis and then provide a case study from our work on importation biological control of the soybean aphid, Aphis glycines. Work on the soybean aphid parasitoid Binodoxys communis has shown that long-distance dispersal of immature parasitoids within winged migrating aphids is unlikely. This is likely good news for importation biological control because parasitoids dispersed in this manner would likely encounter crippling Allee effects. On the other hand, results from a field release study also suggest that female B. communis females (but not males) disperse actively from release sites. This female-biased dispersal may lead to strong mate-finding Allee effects and therefore may make establishment less likely.     

Impacts of a ‘black tide’ harmful algal bloom on rocky-shore intertidal communities on the West Coast of South Africa

Algal blooms commonly occur along the South African west coast. In March 1994 a dense bloom developed within St Helena Bay. Its subsequent decay caused near-shore hypoxia and elevated hydrogen sulphide levels, leading to it being termed a ‘black tide’. The bloom caused immediate massive intertidal mortalities (95% reduction of biomass), significant changes in community structure, and declines in richness and diversity. Only four taxa were not diminished: ephemeral algae, the gastropod Afrolittorina knysnaensis, the anemone Bunodactis reynaudi and the false limpet Siphonaria capensis. This limpet species subsequently increased at impacted sites relative to controls, probably reflecting reduced competition from other grazers. Ephemeral algae flourished during early recolonisation while grazers were depleted, but declined as grazers re-established. Manipulative experiments demonstrated that grazers do have this capability. Perennial algae also flourished, but lagged behind ephemerals, possibly contributing to their decline. Predators took longest to recover. Differences in the responses of species reflect differing tolerances, zonation patterns and biological interactions. Communities at control sites remained unchanged over the four-year study, and those exposed to a low intensity of the bloom were little affected, but communities exposed to its full intensity failed to recover fully within four years. Increasing frequency of harmful algal blooms along the west coast of South Africa could, therefore, significantly alter rocky-shore communities if intervals between bloom events become shorter than recovery times.     

Special Issue on‘‘Metagenomics of Marine Environments’’

<正>We are pleased to announce a special issue on‘‘Metagenomics of Marine Environments’’of the journal Genomics,ProteomicsBioinformatics(GPB),aiming to provide a platform for high-quality papers focusing on the topic and we invite submissions for this special issue(to be published in the fall of 2015).With most microbes being difficult or impossible to culture     

Plant–animal interactions in suburban environments: implications for floral evolution

Plant interactions with mutualists and antagonists vary remarkably across space, and have played key roles in the ecology and evolution of flowering plants. One dominant form of spatial variation is human modification of the landscape, including urbanization and suburbanization. Our goal was to assess how suburbanization affected plant–animal interactions in Gelsemium sempervirens in the southeastern United States, including interactions with mutualists (pollination) and antagonists (nectar robbing and florivory). Based on differences in plant–animal interactions measured in multiple replicate sites, we then developed predictions for how these differences would affect patterns of natural selection, and we explored the patterns using measurements of floral and defensive traits in the field and in a common garden. We found that Gelsemium growing in suburban sites experienced more robbing and florivory as well as more heterospecific but not conspecific pollen transfer. Floral traits, particularly corolla length and width, influenced the susceptibility of plants to particular interactors. Observational data of floral traits measured in the field and in a common garden provided some supporting but also some conflicting evidence for the hypothesis that floral traits evolved in response to differences in species interactions in suburban vs. wild sites. However, the degree to which plants can respond to any one interactor may be constrained by correlations among floral morphological traits. Taken together, consideration of the broader geographic context in which organisms interact, in both suburban and wild areas, is fundamental to our understanding of the forces that shape contemporary plant–animal interactions and selection pressures in native species.     

Egg-size evolution in aquatic environments: does oxygen availability constrain size?

Selection against large eggs has been proposed for aquatic environments, putatively because large eggs should have more difficulty obtaining the required oxygen. Here, we use brown trout (Salmo trutta) eggs to provide an experimental test of this hypothesis. At high levels of dissolved oxygen (14 mg l(-1)), egg survival was high and independent of egg size. At low oxygen levels (2.3 mg l(-1)), survival decreased overall, and was higher for large-egged than small-egged siblings. Thus, contrary to conventional expectation, low oxygen levels selected for large rather than small eggs. A second experiment using Atlantic salmon (S. salar) eggs indicated that oxygen consumption increases relatively slowly with increasing egg mass (allometric constant = 0.44). The failure of the conventional 'bigger is worse during incubation' hypothesis may thus be due to the erroneous assumption that oxygen consumption increases at a greater rate with increasing egg mass than does the egg surface area that is available for oxygen diffusion. We also demonstrate, using data from Atlantic salmon, that nest-specific oxygen consumption decreases with increasing egg size, but that this effect is more pronounced for large than for small females. This may help to explain the positive correlation between adult body size and egg size observed in fishes that cluster their eggs.