Can Mass Trapping Reduce Thrips Damage and Is It Economically Viable? Management of the Western Flower Thrips in Strawberry

The western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is a cosmopolitan, polyphagous insect pest that causes bronzing to fruit of strawberry (Fragaria x ananassa). The main aim of this study was to test whether mass trapping could reduce damage and to predict whether this approach would be economically viable. In semi-protected strawberry crops, mass trapping of F. occidentalis using blue sticky roller traps reduced adult thrips numbers per flower by 61% and fruit bronzing by 55%. The addition of the F. occidentalis aggregation pheromone, neryl (S)-2-methylbutanoate, to the traps doubled the trap catch, reduced adult thrips numbers per flower by 73% and fruit bronzing by 68%. The factors affecting trapping efficiency through the season are discussed. Damage that would result in downgrading of fruit to a cheaper price occurred when bronzing affected about 10% of the red fruit surface. Cost-benefit analysis using this threshold showed that mass trapping of thrips using blue sticky roller traps can be cost-effective in high-value crops. The addition of blue sticky roller traps to an integrated pest management programme maintained thrips numbers below the damage threshold and increased grower returns by a conservative estimate of £2.2k per hectare. Further work is required to develop the F. occidentalis aggregation pheromone for mass trapping and to determine the best timing for trap deployment. Mass trapping of thrips is likely to be cost-effective in other countries and other high-value crops affected by F. occidentalis damage, such as cucumber and cut flowers.     

Can Homegardens Conserve Biodiversity in Bangladesh?

In managed landscapes, tree-dominated habitats often show promise for biodiversity conservation. In Bangladesh where natural forest cover is less than 10 percent, homegardens, which are maintained by at least 20 millions households, represent one possible strategy for biodiversity conservation. This study investigated the floristic and structural diversity of 402 homegardens from six regions across southwestern Bangladesh. All plants were censused, totaling 419 species (59% native), including six IUCN Red Listed. The median homegarden (800 m²) contained a mean of 34 species. Each region contained a mean of 293 species in a mean of 67 homegardens. A total of 49,478 individuals (107 per homegarden and 1003 per hectare) of trees and shrubs were counted from 45.2 ha total sampled area. Thus, significant botanical richness was exhibited in the homegardens across southwestern Bangladesh. However, most species were rare: 82 percent of all species including 189 native were found in 50 or fewer homegardens, and 63 species (36 native) were found in only one or two homegardens. Sixty percent of all tree and shrub species had 50 or fewer individuals each. Thus, whereas richness across the landscape was high, serious effort must be made to increase the populations of most species. We propose three main conservation activities: (1) awareness building; (2) protection of existing individuals of rare species; and (3) propagation. Overlaying all of these activities is the inclusion of local communities in the process, who were the ones to retain these species in homegardens in the first place, and the stakeholders who will determine whether homegardens indeed act as long-term repositories to biodiversity conservation.     

Can altruism evolve in purely viscous populations?

Summary Limited dispersal is often thought to facilitate the evolution of altruism by increasing the degree of relatedness among interacting individuals. Limited dispersal can have additional effects, however, such as local population regulation, that inhibits the evolution of altruism. Many models of structured populations assume that a viscous stage of the life cycle alternates with a global mixing stage, which allows the advantages of interactions among close relatives without the disadvantages of local population regulation. Here we analyse a computer simulation model of pure population viscosity, in which offspring are always deposited close to parents and no global mixing stage exists. As expected, limited dispersal generates a high coefficient of relatedness among interacting individuals. Patches of altruists, however, are unable to export their productivity to other regions of the landscape and are easily invaded by selfish types from neighbouring patches. Unlike models of alternating viscosity, in which high relatedness and local population regulation can be decoupled, these two opposing effects are inextricably linked in purely viscous populations, which therefore are not conducive to the evolution of altruistic traits.     

Can birds count eggs in their nests?

Sensory mechanisms controlling avian clutch size have diversified into distinct types, according to the nature of the input that is used to disrupt the growth of ovarian follicles and hence halt egg‐laying. In an article on brood parasitism, Lyon (2003) claimed that female American Coots Fulica americana can reduce their clutch size on the basis of visual cues in response to eggs laid in their nests by other females; in this species, therefore, egg counting would be used to control clutch size. After a close examination of the physiological determination of clutch size in American Coots, I show that seven of 17 parasitized clutches were smaller than the range controlled through the mechanism using an input to disrupt follicular growth (7–10 eggs per clutch). My reanalysis suggests that American Coots are incapable of adjusting clutch size via counting and re‐asserts that a species that can count eggs has yet to be found among birds that rely upon their own body heat for incubation.     

Can telomerase be put in its place?

The Cajal body is an intriguing nuclear structure present in a great variety of plant, animal, and some fungal cells. Recent work on the ribonucleoprotein enzyme telomerase has indicated an unanticipated degree of intranuclear dynamics of both its RNA and protein subunits. In this issue, Jady et al. place the Cajal body on the intranuclear traffic route of telomerase RNA (Jady et al., 2004).     

Can exotic pine trees assist in restoration?

Invasive exotic woody species, including conifers escaped from plantations, are usually regarded as serious threats to native biodiversity. Becerra & Montenegro (Applied Vegetation Science, 16, 2013, 2) present an interesting example of invasive Pinus radiata facilitating native woody regeneration in semi‐arid central Chile. However, the positive value of invasive conifers for restoration and conservation will not necessarily apply in all situations.     

Can Simpson's paradox explain co-operation in Pseudomonas aeruginosa biofilms?

Co-operative behaviours, such as the production of public goods, are commonly displayed by bacteria in biofilms and can enhance their ability to survive in environmental or clinical settings. Non-co-operative cheats commonly arise and should, theoretically, disrupt co-operative behaviour. Its stability therefore requires explanation, but no mechanisms to suppress cheating within biofilms have yet been demonstrated experimentally. Theoretically, repeated aggregation into groups, interleaved with dispersal and remixing, can increase co-operation via a 'Simpson's paradox'. That is, an increase in the global proportion of co-operators despite a decrease in within-group proportions, via differential growth of groups. We investigate the hypothesis that microcolony formation and dispersal produces a Simpson's paradox that explains bacterial co-operation in biofilms. Using the production of siderophores in Pseudomonas aeruginosa as our model system for co-operation, we use well-documented co-operator and siderophore-deficient cheat strains to measure the frequency of co-operating and cheating individuals, in-situ within-microcolony structures. We detected significant within-type negative density-dependant effects that vary over microcolony development. However, we find no evidence of Simpson's paradox. Instead, we see clear within-microcolony spatial structure (cheats occupying the interior portions of microcolonies) that may violate the assumption required for Simpson's paradox that group members share equally in the public good.     

Can cellular models revolutionize drug discovery in Parkinson's disease?

The study of mechanisms that underlie Parkinson's disease (PD), as well as translational drug development, has been hindered by the lack of appropriate models. Both cell culture systems and animal models have limitations, and to date none faithfully recapitulate all of the clinical and pathological phenotypes of the disease. In this review we examine the various cell culture model systems of PD, with a focus on different stem cell models that can be used for investigating disease mechanisms as well as drug discovery for PD. We conclude with a discussion of recent discoveries in the field of stem cell biology that have led to the ability to reprogram somatic cells to a pluripotent state via the use of a combination of genetic factors; these reprogrammed cells are termed “induced pluripotent stem cells” (iPSCs). This groundbreaking technique allows for the derivation of patient-specific cell lines from individuals with sporadic forms of PD and also those with known disease-causing mutations. Such cell lines have the potential to serve as a human cellular model of neurodegeneration and PD when differentiated into dopaminergic neurons. The hope is that these iPSC-derived dopaminergic neurons can be used to replicate the key molecular aspects of neural degeneration associated with PD. If so, this approach could lead to transformative new tools for the study of disease mechanisms. In addition, such cell lines can be potentially used for high-throughput drug screening. While not the focus of this review, ultimately it is envisioned that techniques for reprogramming of somatic cells may be optimized to a point sufficient to provide potential new avenues for stem cell-based restorative therapies.     

Can the failure to punish promote cheating in mutualism?

A key challenge in the study of mutualism is to understand the mechanisms that prevent cheating. In some systems, host retaliation against cheaters prevents the breakdown of cooperation. Here, we focus on the converse of this demonstration, and ask whether hosts that fail to retaliate are commonly inhabited by cheaters. We do so using the classic ant–plant interaction, in which plants provide ant-housing (domatia) in return for protection from herbivores. Our model system is the rattan ant-palm Korthalsia furtadoana , which grows swollen leaf sheaths as domatia and associates with two species of obligate host-ants, Camponotus sp90 and C. sp93 , and with facultative Crematogaster and 'tramp' ant species. One ant-tree species is known to retaliate by tying the growth of domatia to the successful protection of new leaves, and non-protecting cheaters are rare. In contrast, K. furtadoana grows the domatium before the new leaf develops, suggesting that sanctioning may not be possible. We experimentally simulated herbivory by cutting leaves from shoots and found no difference in the mortality and growth of domatia on such 'cheated' shoots than on controls, confirming that K. furtadoana cannot sanction non-protectors. We then investigated the intensity of protection that Camponotus and Crematogaster ant-symbionts provide K. furtadoana . We demonstrate that C. sp90 , which only inhabit half of colonised plants, vigorously protects leaves, that C. sp93 rarely protects, and that Crematogaster never protects. We then show that plants inhabited by C. sp90 have a higher growth rate than those inhabited by C. sp93 . We conclude that C. sp90 is a protection mutualist, while C. sp93 and Crematogaster are parasites, the first such demonstrations for an ant–palm interaction. The presence of commonly occurring parasites, as well as rare tramp ants, provides the first clear correlative evidence that an inability to punish results in abundant cheating.     

Can antioxidant vitamins materially reduce oxidative damage in humans?

Endogenous oxidative damage to proteins, lipids, and DNA is thought to be an important etiologic factor in aging and the development of chronic diseases such as cancer, atherosclerosis, and cataract formation. The pathology associated with these diseases is likely to occur only after the production of reactive oxygen species has exceeded the body's or cell's capacity to protect itself and effectively repair oxidative damage. Vitamin C, vitamin E, and beta-carotene, often referred to as "antioxidant vitamins," have been suggested to limit oxidative damage in humans, thereby lowering the risk of certain chronic diseases. However, epidemiological studies and clinical trials examining the efficacy of antioxidant vitamins, either individually or in combination, to affect disease outcome rarely address possible underlying mechanisms. Thus, in these studies it is often assumed that antioxidant vitamins act by lowering oxidative damage, but evidence in support of this contention is not provided. Therefore, in this review, we examine the scientific evidence that supplementation of humans with vitamin C, vitamin E, or beta-carotene lowers in vivo oxidative damage to lipids, proteins, or DNA based on the measurement of oxidative biomarkers, not disease outcome. With the only exception of supplemental vitamin E, and possibly vitamin C, being able to significantly lower lipid oxidative damage in both smokers and nonsmokers, the current evidence is insufficient to conclude that antioxidant vitamin supplementation materially reduces oxidative damage in humans.     

Can R*s Predict Invasion in Semi-arid Grasslands?

We estimated R*s and tested the applicability of R* theory on nonindigenous plant invasions in semi-arid rangeland. R* is the concentration of a resource that a species requires to survive in a habitat. R* theory predicts that a species with a lower R* for the most limiting resource will competitively displace a species with a higher R* under equilibrium conditions. In a greenhouse, annual sunflower (Helianthus annuus L.), bluebunch wheatgrass (Agropyron spicatum Pursh), and spotted knapweed (Centaurea maculosa Lam.) were grown in monoculture and 2- and 3-species mixtures for three growth periods in an attempt to reduce soil NO₃-N concentrations below each species’ R*. At the end of each growth period, aboveground biomass by species and soil plant available nitrogen were sampled. Decreasing biomass coupled with decreasing soil plant available nitrogen was used to quantify R*s for the three species. R*s for annual sunflower, bluebunch wheatgrass, and spotted knapweed were estimated to be 0.6±0.16 ppm NO₃⁻, less than 0.05 ppm NO₃⁻, and 0.6±0.13 ppm NO₃⁻, respectively. Estimated R*s did not predict the outcome of competition among species. To successfully predict plant community dynamics on semi-arid rangeland with and without the presence of a nonindigenous invasive species, a more comprehensive model that includes mechanisms in addition to competition may have to be considered. We speculate that R* theory may prove most useful for predicting the outcome of competition within functional groups.     

Can phenotypic plasticity in Rubisco performance contribute to photosynthetic acclimation?

Photosynthetic acclimation varies among species, which likely reveals variations at the biochemical level in the pathways that constitute carbon assimilation and energy transfer. Local adaptation and phenotypic plasticity affect the environmental response of photosynthesis. Phenotypic plasticity allows for a wide array of responses from a single individual, encouraging fitness in a broad variety of environments. Rubisco catalyses the first enzymatic step of photosynthesis, and is thus central to life on Earth. The enzyme is well conserved, but there is habitat-dependent variation in kinetic parameters, indicating that local adaptation may occur. Here, we review evidence suggesting that land plants can adjust Rubisco’s intrinsic biochemical characteristics during acclimation. We show that this plasticity can theoretically improve CO₂ assimilation; the effect is non-trivial, but small relative to other acclimation responses. We conclude by discussing possible mechanisms that could account for biochemical plasticity in land plant Rubisco.     

Can women in labor give informed consent to epidural analgesia?

There are reasons to believe that decision‐making capacity (mental competence) of women in labor may be compromised in relation to giving informed consent to epidural analgesia. Not only severe labor pain, but also stress, anxiety, and premedication of analgesics such as opioids, may influence women’s decisional capacity. Decision‐making capacity is a complex construct involving cognitive and emotional components which cannot be reduced to ‘understanding’ alone. A systematic literature search identified a total of 20 empirical studies focused on women’s decision‐making about epidural analgesia for labor pain. Our review of these studies suggests that empirical evidence to date is insufficient to determine whether women undergoing labor are capable of consenting to epidural analgesia. Given such uncertainties, sufficient information about pain management should be provided as part of prenatal education and the consent process must be carefully conducted to enhance women’s autonomy. To fill in the significant gap in clinical knowledge about laboring women’s decision‐making capacity, well‐designed prospective and retrospective studies may be required.