Infant kidnapping among group-living rhesus macaques: Why don't mothers rescue their infants?

Observations of infant kidnapping among group-living rhesus macaques and anecdotal evidence in the literature indicate that monkey mothers do not attempt to forcibly retrieve their infants from kidnappers even though kidnapping may have potentially fatal consequences for the infant. Based on the available evidence, the potential risk of injury to the mother and/or the infant in case of precipitated conflict with the kidnapper may conceivably account for the lack of maternal intervention during kidnapping. Although this hypothesis requires further testing, maternal refrainment from intervention seems to be a maladaptive response in cases of long-lasting kidnappings by nonlactating females because the infant's life is at stake and the cost of the loss of an infant is presumably higher than the potential risk of injury in a fight.     

Infection and food: a factor in sudden infant death syndrome?

Despite the identification of risk factors for sudden infant death syndrome (SIDS) and decreased SIDS rates in many countries, there is still no coherent, widely accepted, mechanistic explanation for SIDS. As an extension of our work on the infectious aetiology of SIDS, we have explored the prediction that infectious agents might reach susceptible infants and babies, via particular sources of food. In this ecological study, we demonstrated significant correlations between SIDS rates and exposure to meat from some sources, and we propose that more detailed studies be carried out.     

Do β-Cells Generate Peroxynitrite in Response to Cytokine Treatment?

The purpose of this study was to determine the reactive species that is responsible for cytokine-mediated β-cell death. Inhibitors of inducible nitric oxide synthase prevent this death, and addition of exogenous nitric oxide using donors induces β-cell death. The reaction of nitric oxide with superoxide results in the generation of peroxynitrite, and this powerful oxidant has been suggested to be the mediator of β-cell death in response to cytokine treatment. Recently, coumarin-7-boronate has been developed as a probe for the selective detection of peroxynitrite. Using this reagent, we show that addition of the NADPH oxidase activator phorbol 12-myristate 13-acetate to nitric oxide-producing macrophages results in peroxynitrite generation. Using a similar approach, we demonstrate that cytokines fail to stimulate peroxynitrite generation by rat islets and insulinoma cells, either with or without phorbol 12-myristate 13-acetate treatment. When forced to produce superoxide using redox cyclers, this generation is associated with protection from nitric oxide toxicity. These findings indicate that: (i) nitric oxide is the likely mediator of the toxic effects of cytokines, (ii) β-cells do not produce peroxynitrite in response to cytokines, and (iii) when forced to produce superoxide, the scavenging of nitric oxide by superoxide is associated with protection of β-cells from nitric oxide-mediated toxicity.     

Do plants use airborne cues to recognize herbivores on their neighbours?

Plants show defensive responses after exposure to volatiles from neighbouring plants infested by herbivores. When a plant’s neighbours host only species of herbivores that do not feed on the plant itself, the plant can conserve energy by maintaining a low defence level. An intriguing question is whether plants respond differently to volatiles from plants infested by herbivores that pose greater or lesser degrees of danger. We examined the secretion of extrafloral nectar (EFN) in lima bean plants exposed to volatiles from cabbage plants infested by common cutworm, two-spotted spider mites, or diamondback moth larvae. Although the first two herbivore species feed on lima bean plants, diamondback moth larvae do not. As a control, lima bean plants were exposed to volatiles from uninfested cabbage plants. Only when exposed to volatiles from cabbage plants infested by spider mites did lima bean plants significantly increase their EFN secretion compared with the control. Increased EFN secretion can function as an indirect defence by supplying the natural enemies of herbivores with an alternative food source. Of the three herbivore species, spider mites were the most likely to move from cabbage plants to lima bean plants and presumably posed the greatest threat. Although chemical analyses showed differences among treatments in volatiles produced by herbivore-infested cabbage plants, which compounds or blends triggered the increased secretion of EFN by lima bean plants remains unclear. Thus, our results show that plants may tune their defence levels according to herbivore risk level.     

Do plants adjust their sex allocation and secondary sexual morphology in response to their neighbours?

Background and aims

Changes in the sex allocation (i.e. in pollen versus seed production) of hermaphroditic plants often occur in response to the environment. In some homosporous ferns, gametophytes choose their gender in response to chemical cues sent by neighbours, such that spores develop as male gametophytes if they perceive a female or hermaphrodite nearby. Here it is considered whether a similar process might occur in the androdioecious angiosperm species Mercurialis annua, in which males co-occur with hermaphrodites; previous work on a Spanish population of M. annua found that individuals were more likely to develop as males at high density.

Methods

Using a novel approach to treat plants with leachate from pots containing males or hermaphrodites of M. annua, the hypothesis that individuals assess their mating opportunities, and adjust their sex expression accordingly, was tested through an exchange of chemical cues through the soil.

Key Results

For the population under study, from Morocco, no evidence was found for soil-signal-dependent sex expression: neither sex ratios nor sex allocation differed among experimental treatments.

Conclusions

The results imply either that the Moroccan population under study behaves differently from that previously studied in Spain (pointing to potential geographical variation in plasticity for sex expression), or that our method failed to capture the signals used by M. annua for adjustment of sex expression.     

Do insects lose flight before they lose their wings? Population genetic structure in subalpine stoneflies

Wing reduction and flightlessness are common features of alpine and subalpine insects, and are typically interpreted as evolutionary adaptations to increase fecundity and promote local recruitment. Here, we assess the impact of wing reduction on dispersal in stoneflies (Plecoptera: Gripopterygidae: Zelandoperla ) in southern New Zealand. Specifically, we present comparative phylogeographic analyses (COI; H3) of strong-flying Zelandoperla decorata (144 individuals, 63 localities) vs. the co-distributed but weak-flying Zelandoperla fenestrata species group (186 individuals, 81 localities). The latter group exhibits a variety of morphotypes, ranging from fully winged to completely wingless. Consistent with its capacity for strong flight-mediated dispersal, Z .  decorata exhibited no substantial phylogeographic differentiation across its broad South Island range. Conversely the weak-flying fenestrata species group exhibited substantial genetic structure across both fine and broad geographic scales. Intriguingly, the variable degrees of wing development observed within the fenestrata species group had no apparent impact on levels of phylogeographic structure, which were high regardless of morphotype, suggesting that even fully winged specimens of this group do not fly. This finding implies that Zelandoperla flight loss occurs independently of wing loss, and might reflect underlying flight muscle reduction.     

Do kleptoparasites reduce their own foraging effort in order to detect kleptoparasitic opportunities?: An empirical test of a key assumption of kleptoparasitic models

Determining if, or when, individuals trade off time spent personally feeding against time spent monitoring others for kleptoparasitism opportunities is essential to an understanding of the evolution of scrounging and usurpation behaviours. We provide a first field test of whether kleptoparasites reduce their personal foraging effort in situations where the frequency and rewards of kleptoparasitism increase. We provided experimental food patches for wild European blackbirds that varied in the distribution of prey and that had a potentially high rate of kleptoparasitism within pairs of blackbirds feeding in them. Although individuals differed in their rate of kleptoparasitism, they did not vary in the size of the reward that they gained from kleptoparasitism. As prey became more clumped, kleptoparasitism rate and its reward per incident increased on average. There was, however, no evidence that individuals that were kleptoparasitising more quickly and/or at a higher frequency had lower personal foraging effort. In contrast, foraging effort increased in both birds compared to when they were foraging alone, independent of dominance, kleptoparasitic opportunity or reward. Our evidence suggests that in some circumstances a kleptoparasite can detect kleptoparasitic opportunities without compromising its own personal foraging rate.     

Bioengineering nitrogen acquisition in rice: can novel initiatives in rice genomics and physiology contribute to global food security?

Rice is the most important crop species on earth, providing staple food for 70% of the world's human population. Over the past four decades, successes in classical breeding, fertilization, pest control, irrigation and expansion of arable land have massively increased global rice production, enabling crop scientists and farmers to stave off anticipated famines. If current projections for human population growth are correct, however, present rice yields will be insufficient within a few years. Rice yields will have to increase by an estimated 60% in the next 30 years, or global food security will be in danger. The classical methods of previous green revolutions alone will probably not be able to meet this challenge, without being coupled to recombinant DNA technology. Here, we focus on the promise of these modern technologies in the area of nitrogen acquisition in rice, recognizing that nitrogen deficiency compromises the realization of rice yield potential in the field more than any other single factor. We summarize rice-specific advances in four key areas of research: (1). nitrogen fixation, (2). primary nitrogen acquisition, (3). manipulations of internal nitrogen metabolism, and (4). interactions between nitrogen and photosynthesis. We develop a model for future plant breeding possibilities, pointing out the importance of coming to terms with the complex interactions among the physiological components under manipulation, in the context of ensuring proper targeting of intellectual and financial resources in this crucial area of research.     

Mimicry on the edge: why do mimics vary in resemblance to their model in different parts of their geographical range?

Batesian mimics-benign species that predators avoid because they resemble a dangerous species-often vary geographically in resemblance to their model. Such geographical variation in mimic-model resemblance may reflect geographical variation in model abundance. Natural selection should favour even poor mimics where their model is common, but only good mimics where their model is rare. We tested these predictions in a snake-mimicry complex where the geographical range of the mimic extends beyond that of its model. Mimics on the edge of their model's range (where the model was rare) resembled the model more closely than did mimics in the centre of their model's range (where the model was common). When free-ranging natural predators on the edge of the model's range were given a choice of attacking replicas of good or poor mimics, they avoided only good mimics. By contrast, those in the centre of the model's range attacked good and poor mimics equally frequently. Generally, although poor mimics may persist in areas where their model is common, only the best mimics should occur in areas where their model is rare. Thus, counter-intuitively, the best mimics may occur on the edge of their model's range.     

Distribution of Tardigrades within a Moss Cushion: Do Tardigrades Migrate in Response to Changing Moisture Conditions?

The distribution of tardigrades within the layers of the cushion moss Grimmia alpicola Hedwig, 1801 was investigated. The aim of this study was to determine the tardigrade species present within the moss layers during both wet and dry periods and to determine if migration occurred in response to changing moisture conditions. Samples of the moss were removed from concrete caps on brick fence posts before and after rainfall and separated into two sections (top and bottom). The tardigrades from each layer and moisture condition were identified to species. Data for each species were statistically analyzed with a two-way analysis of variance (ANOVA) to compare the numbers of individuals present in the top and bottom layers of the moss under both wet and dry conditions.

Five tardigrade species were identified, including two species new to science: Macrobiotus sp. n.; Milnesium tardigradum Doyère, 1840; Echiniscus viridissimus Peterfi, 1956; Echiniscus perviridis Ramazzotti, 1959; and Echiniscus sp. n. The new species will be described in a forthcoming paper. No significant differences were found in the numbers of individuals of four of the five species in each layer within the moss or for each moisture condition. Only one species, E. viridissimus, was significantly more frequent in the top layer of the moss, regardless of moisture condition.

Migration within the moss cushion was not detected in any of these five species as a result of changes in moisture conditions. In xeric moss species, it may not be beneficial for tardigrades to migrate to avoid desiccation. Instead, they apparently undergo anhydrobiosis in both the top and bottom layers of the moss cushion.     

Do dung beetle larvae need microbial symbionts from their parents to feed on dung?

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Vectors based on autonomous parvoviruses: novel tools to treat cancer?

Autonomous parvoviruses are small nuclear-replicating DNA viruses. The rodent parvoviruses usually are non- or weakly pathogenic in adult animals, bind to surface receptors which are expressed on most cells, and do not appear to integrate into host chromosomes during either lytic or persistent infections. Interestingly, malignant transformation of the target cells was often found to correlate with an increase in their capacity for amplifying and/or expressing the incoming parvoviral DNA, and is associated with oncolysis, i.e., the selective killing of the infected tumor cells. Moreover, the closely related parvoviruses MVM, H-1 and LuIII efficiently infect human cell lines. This finding makes these parvoviruses promising candidate vectors for therapies that require transient expression of a transduced gene. In particular, parvoviruses may be suitable to target and kill tumor cells and simultaneously deliver appropriate transgenes, e.g., genes coding for immuno-stimulatory factors. Pilot experiments performed in animals to assess whether parvovirus-based vectors carrying the interleukin 2 (IL-2) cytokine gene have reinforced anti-cancer capacity showed that these recombinant viruses suppressed tumor formation more efficiently than viruses devoid of a transgene. Strong anti-cancer effects of recombinant parvoviruses expressing interferon gamma-inducible protein 10 (IP-10) and monocyte chemotactic protein 3 (MCP-3) were also observed against established hemangiosarcomas and melanomas in immuno-competent mice, respectively. Altogether, these data illustrate the enormous potential of recombinant autonomous parvoviruses as anti-tumor agents and give hope of using them against human cancer.     

Angular Oscillation of Solid Scatterers in Response to Progressive Planar Acoustic Waves: Do Fish Otoliths Rock?

Fish can sense a wide variety of sounds by means of the otolith organs of the inner ear. Among the incompletely understood components of this process are the patterns of movement of the otoliths vis-à-vis fish head or whole-body movement. How complex are the motions? How does the otolith organ respond to sounds from different directions and frequencies? In the present work we examine the responses of a dense rigid scatterer (representing the otolith) suspended in an acoustic fluid to low-frequency planar progressive acoustic waves. A simple mechanical model, which predicts both translational and angular oscillation, is formulated. The responses of simple shapes (sphere and hemisphere) are analyzed with an acoustic finite element model. The hemispherical scatterer is found to oscillate both in the direction of the propagation of the progressive waves and also in the plane of the wavefront as a result of angular motion. The models predict that this characteristic will be shared by other irregularly-shaped scatterers, including fish otoliths, which could provide the fish hearing mechanisms with an additional component of oscillation and therefore one more source of acoustical cues.     

Schistosomiasis in African infants and preschool children: to treat or not to treat?

The occurrence of schistosomiasis in African infants and preschool children has been largely overlooked, with preventive chemotherapy usually focused on school-aged children instead. Two recent surveys by Bosompem et al. and Odogwu et al. have shown that schistosomiasis in younger children is much more common than previously thought. This article highlights the importance of the disease in this age group and discusses the future prospects for schistosomiasis control.     

Use of leaves to inspect ectoparasites in wild chimpanzees: a third cultural variant?

We report 26 cases of using leaves as tools with which wild chimpanzees (Pan troglodytes schweinfurthii) in the Sonso community, Budongo Forest, Uganda, appeared to inspect objects removed during grooming. Careful removal of potential ectoparasites and delicate lip or manual placement on leaves followed by intense visual examination characterised this behaviour. It appears to be done to judge whether either ingestion or discarding is most appropriate, the former occurring in most cases. This behaviour may represent a third variant of ectoparasite handling, different from those described at Taï and Gombe, yet sharing features with the latter. These two East African techniques may thus have evolved from leaf grooming.