Odysseys in Pastryland – a bird’s eye view of microevolution

Theory based models of microevolutionary processes are difficult to test in the wild, because the data relating to the specific predictions of the model must be disentangled from the complexity of the species’ overall ecology. Since the 1960s some evolutionary ecologists have been using field experiments involving artificial prey and wild predators – the ecology of the ‘prey’ is under the control of the experimenter, which greatly simplifies the logistics of testing specific microevolutionary models. So far, this technique – typically using prey ‘worms’ made from pastry and wild passerine birds as predators – has been used to test theoretical models of crypsis, directional vs. stabilising selection, apostatic selection, polymorphism, and mimicry systems (Allen, Cooper, Hall, and McHenry 1993). To date, the ‘Pastryland’ technique has been used by ecologists at the Universities of Reading and Southampton in the UK.Because it is a simple model of microevolution in the real world, and because individual experiments rarely require more than a few days to complete, ‘Pastryland’ has also been used to demonstrate the process of natural selection to tertiary science students (Allen, Cooper, Hall, and McHenry 1993). Natural selection is a powerful but very subtle theory, and is hard to grasp without some sort of real world demonstration or example. The logistics of Pastryland experiments mean that it can easily be performed as part of a tertiary field-based activity, with students intimately involved with the running of the experiment. Students are immersed in evolution by taking an active role in the process. Although the pastry ‘prey’ are artificial, the technique relies ultimately on the behaviour of wild predators, as a ‘real’ selective pressure, enhancing student concept acquisition in evolutionary theory. Pastryland was trialed as a group field project for third year ecology undergraduates at the University of Newcastle. They tested a specific prediction about the dynamics of mimicry systems that has not yet been tested experimentally. This was the first time (to our knowledge) that Pastryland has been used within a teaching context in Australia, and we adapted the technique to make use of common wild birds in Australian urban environments. In the UK, the most important predator was the blackbird (Turdus merula) – in coastal NSW, the main predators are noisy miners (Manorina melanocephala), magpies (Gymnorhina tibicen), and currawongs (Strepera graculina). Students also modified the experimental design to improve controls, and involved local high schools in the hope that the technique would ‘catch-on’ with science teachers

Towards inclusive teaching practice in science education in relation to gender and sexuality

In recent years, there has been recognition internationally of the value and importance of inclusive curriculum in tertiary teaching practice. Indeed, in the international literature there have been significant advances identifying what makes science education interesting, relevant, accessible and inclusive to all students, especially for women and those from culturally diverse backgrounds (Bianchini, Whitney, Breton, and Hilton-Brown 2002). Unfortunately, much of this work is not translated to current pedagogical practice in a tertiary science environment. The way in which concepts and activities are presented may marginalise or exclude particular students. Less thought and consideration has been afforded to those students who identify as gay, lesbian, bisexual, transgendered or intersex. Is the way we present and examine biology and the natural world sensitive to an individual’s identity? (Good, Haffner and Peebles 2000; Snyder and Broadway 2004). We provide a series of examples where current pedagogies in biology may exclude or marginalise students in terms of gender and sexuality and provide a framework of contextual factors which encourage all students to engage and excel in a supportive environment within the biological sciences

Legacy metal contamination is reflected in the fish gut microbiome in an urbanised estuary

Estuaries are critical habitats subject to a range of stressors requiring effective management. Microbes are gaining recognition as effective environmental indicators, however, the response of host associated communities to stressors remains poorly understood. We examined microbial communities from seawater, sediments and the estuarine fish Pelates sexlineatus, in Australia\u27s largest urbanised estuary, and hypothesised that anthropogenic contamination would be reflected in the microbiology of these sample types. The human faecal markers Lachno3 and HF183 were not detected, indicating negligible influence of sewage, but a gradient in copy numbers of the class 1 integron (intI-1), which is often used as a marker for anthropogenic contamination, was observed in sediments and positively correlated with metal concentrations. While seawater communities were not strongly driven by metal contamination, shifts in the diversity and composition of the fish gut microbiome were observed, with statistical links to levels of metal contamination (F2, 21 = 1.536, p \u3c 0.01). Within the fish gut microbiome, we further report increased relative abundance of amplicon sequence variants (ASVs; single inferred DNA sequences obtained in sequencing) identified as metal resistant and potentially pathogenic genera, as well as those that may have roles in inflammation. These results demonstrate that microbial communities from distinct habitats within estuarine systems have unique response to stressors, and alterations of the fish gut microbiome may have implications for the adaptation of estuarine fish to legacy metal contamination

VCAM-1 and VLA-4 Modulate Dendritic Cell IL-12p40 Production in Experimental Visceral Leishmaniasis

Vascular cell adhesion molecule-1 (VCAM-1) interacts with its major ligand very late antigen-4 (VLA-4) to mediate cell adhesion and transendothelial migration of leukocytes. We report an important role for VCAM-1/VLA-4 interactions in the generation of immune responses during experimental visceral leishmaniasis caused by Leishmania donovani. Our studies demonstrate that these molecules play no direct role in the recruitment of leukocytes to the infected liver, but instead contribute to IL-12p40-production by splenic CD8+ dendritic cells (DC). Blockade of VCAM-1/VLA-4 interactions using whole antibody or anti-VCAM-1 Fab′ fragments reduced IL-12p40 mRNA accumulation by splenic DC 5 hours after L. donovani infection. This was associated with reduced anti-parasitic CD4+ T cell activation in the spleen and lowered hepatic IFNγ, TNF and nitric oxide production by 14 days post infection. Importantly, these effects were associated with enhanced parasite growth in the liver in studies with either anti-VCAM-1 or anti-VLA-4 antibodies. These data indicate a role for VCAM-1 and VLA-4 in DC activation during infectious disease

Genomic investigations of unexplained acute hepatitis in children

Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children

Homosexual behaviour in birds: frequency of expression is related to parental care disparity between the sexes

Homosexual behaviour occurs in over 130 species of birds, yet explaining its maintenance in evolutionary terms appears problematic at face value, as such sexual behaviours do not seem in immediate pursuit of reproductive goals. Parental care sexual conflict theory predicts that release from parental care translates to an increased propensity towards polygamous sexual behaviour. We hypothesized that homosexual behaviour(s) may be expected to increase in frequency for the sex that invests less in parental care and potentially enjoys increased mating opportunities. Consistent with our predictions, lower relative contribution to parental care for a particular sex is related to increased frequency of occurrence of homosexual behaviour. For males, highly polygynous species with minimal male parental investment exhibit higher frequencies of male homosexual behaviour, including male–male mounting and especially courtship. In socially monogamous species, male parental investment is greater, and the expression of male homosexual behaviour is lower. Similarly, among pair-bonding species, frequencies of male–male pair bonding increase with decreases in male contribution to care relative to females. When females of socially monogamous species provide less care than males, they exhibit higher frequencies of homosexual behaviour, namely pair bonding and courtship activities. Conversely, when females of polygynous species provide the bulk of parental care, female–female sexual behaviour is infrequently expressed. Homosexual behaviour in birds is more likely to occur under scenarios of enhanced mating opportunity without necessarily influencing reproductive success and thus may exist neutrally, or alternatively provide a behavioural template co-opted for adaptive design

Accumulation and partitioning of heavy metals in mangroves: A synthesis of field-based studies

We report the findings of a comparative analysis examining patterns of accumulation and partitioning of the heavy metals copper (Cu), lead (Pb) and zinc (Zn) in mangroves from available field-based studies to date, employing both species level analyses and a phylogenetic approach. Despite mangroves being a taxonomically diverse group, metal accumulation and partitioning for all metals examined were broadly similar across genera and families. Patterns of metal accumulation were also similar regardless of whether species were classified as salt secreting or non-secreting. Metals were accumulated in roots to concentrations similar to those of adjacent sediments with root bio-concentration factors (BCF; ratio of root metal to sediment metal concentration) o

Same-sex sexual behavior in birds: expression is related to social mating system and state of development at hatching

We report the findings of a phylogenetic comparative analysis examining patterns and frequency of occurrence of same-sex courtship and mounting behavior in birds. Our analysis has shown associations between same-sex sexual behavior and both mating system and degree of precociousness at hatching. The patterns of expression and frequency of occurrence of same-sex sexual behavior differed markedly for males and females. Patterns of same-sex sexual expression reflected the competitive sexes that actively solicit sexual interactions in heterosexual encounters. Male–male (MM) sexual behavior occurred across all mating systems, but MM mounting was significantly more prevalent in those species with facultative polygamy. The frequency of MM sexual behavior increased with degree of polygamy. Female–female (FF) sexual behavior (especially courtship) occurred most frequently in socially monogamous species and rarely occurred in species that display obligate polygamy (predominantly polygynous species). Both expression and frequency of FF sexual behavior was strongly related to the precocial state of development at hatching. FF sexual behavior is more likely to occur in species in which monogamy occurs together with the production of precocial offspring; that is, in monogamous species that are exceptions to the more common altricial mode of development. We suggest that requirement of biparental care in monogamous species may influence the greater expression of FF sexual behavior and longer term associations. Both spatial and behavioral dispersion of females and engagement in uniparental care may be important in explaining the lower incidence of FF sexual behavior in polygynous species. Social contexts where males congregate at communal leks or display areas may influence the greater expression and frequency of MM sexual behavior in polygynous species