• The Jan Mayen microplate complex and the Wilson cycle

      Schiffer, Christian; Peace, Alexander; Phethean, Jordan; Gernigon, Laurent; McCaffrey, Ken; Petersen, Kenni D.; Foulger, Gillian; Durham University; Memorial University of Newfoundland, Canada; Geological Survey of NorwayLeiv; et al. (Geological Society of London, 2018-02-01)
      The opening of the North Atlantic region was one of the most important geodynamic events that shaped the present day passive margins of Europe, Greenland and North America. Although well-studied, much remains to be understood about the evolution of the North Atlantic, including the role of the Jan Mayen microplate complex. Geophysical data provide an image of the crustal structure of this microplate and enable a detailed reconstruction of the rifting and spreading history. However, the mechanisms that cause the separation of microplates between conjugate margins are still poorly understood. We assemble recent models of rifting and passive margin formation in the North Atlantic and discuss possible scenarios that may have led to the formation of the Jan Mayen microplate complex. This event was probably triggered by regional plate tectonic reorganizations rejuvenating inherited structures. The axis of rifting and continental break-up and the width of the Jan Mayen microplate complex were controlled by old Caledonian fossil subduction/suture zones. Its length is related to east–west-oriented deformation and fracture zones, possibly linked to rheological heterogeneities inherited from the pre-existing Precambrian terrane boundaries.
    • Larger ejaculate volumes are associated with a lower degree of polyandry across bushcricket taxa

      Vahed, Karim; University of Derby (The Royal Society, 2006-09-22)
      In numerous insects, including bushcrickets (Tettigoniidae), males are known to transfer substances in the ejaculate that inhibit the receptivity of females to further matings, but it has not yet been established whether these substances reduce the lifetime degree of polyandry of the female. The aim of this study was to test the hypothesis that larger ejaculate volumes should be associated with a lower degree of polyandry across tettigoniid taxa, controlling for male body mass and phylogeny. Data on ejaculate mass, sperm number, nuptial gift mass and male mass were taken primarily from the literature. The degree of polyandry for 14 species of European bushcrickets was estimated by counting the number of spermatodoses within the spermathecae of field-caught females towards the end of their adult lifespans. Data for four further species were obtained from the literature. Data were analysed by using both species regression and independent contrasts to control for phylogeny. Multiple regression analysis revealed that, as predicted, there was a significant negative association between the degree of polyandry and ejaculate mass, relative to male body mass, across bushcricket taxa. Nuptial gift size and sperm number, however, did not contribute further to interspecific variation in the degree of polyandry. A positive relationship was found, across bushcricket taxa, between relative nuptial gift size and relative ejaculate mass, indicating that larger nuptial gifts allow the male to overcome female resistance to accepting large ejaculates. This appears to be the first comparative evidence that males can manipulate the lifetime degree of polyandry of their mates through the transfer of large ejaculates.
    • Larger testes are associated with a higher level of polyandry, but a smaller ejaculate volume, across bushcricket species (Tettigoniidae)

      Vahed, Karim; Parker, Darren James; Gilbert, James D. J.; University of Derby (The Royal Society, 2010-11-10)
      While early models of ejaculate allocation predicted that both relative testes and ejaculate size should increase with sperm competition intensity across species, recent models predict that ejaculate size may actually decrease as testes size and sperm competition intensity increase, owing to the confounding effect of potential male mating rate. A recent study demonstrated that ejaculate volume decreased in relation to increased polyandry across bushcricket species, but testes mass was not measured. Here, we recorded testis mass for 21 bushcricket species, while ejaculate ( ampulla) mass, nuptial gift mass, sperm number and polyandry data were largely obtained from the literature. Using phylogenetic-comparative analyses, we found that testis mass increased with the degree of polyandry, but decreased with increasing ejaculate mass. We found no significant relationship between testis mass and either sperm number or nuptial gift mass. While these results are consistent with recent models of ejaculate allocation, they could alternatively be driven by substances in the ejaculate that affect the degree of polyandry and/or by a trade-off between resources spent on testes mass versus non-sperm components of the ejaculate.
    • Life history, environment and extinction of the scallop Carolinapecten eboreus (Conrad) in the Plio-Pleistocene of the U.S. eastern seaboard.

      Johnson, Andrew L. A.; Valentine, Annemarie M.; Leng, Melanie J.; Schöne, Bernd R.; Sloane, Hilary J.; University of Derby; Nottingham Trent University; British Geological Survey; University of Mainz (SEPM (Society for Sedimentary Geology), 2019-02-01)
      Plio-Pleistocene mass extinction of marine bivalves on the U.S. eastern seaboard has been attributed to declines in temperature and primary production. We investigate the relationship of growth rate in the scallop Carolinapecten eboreus to variation in these parameters to determine which contributed to its extinction. We use ontogenetic profiles of shell d18O to estimate growth rate and seasonal temperature, microgrowth-increment data to validate d18O-based figures for growth rate, and shell d13C to supplement assemblage evidence of production. Postlarval growth started in the spring/summer in individuals from the Middle Atlantic Coastal Plain but in the autumn/winter in some from the Gulf Coastal Plain. Growth rate typically declined with age and was usually higher in summer than winter. Many individuals died in winter but the largest forms typically died in spring, possibly on spawning for the first time. No individuals lived longer than two years and some grew exceedingly fast overall, up to 60% more rapidly than any other scallop species (, 145.7 mm in a year). Faster growth was generally achieved by secreting more rather than larger microgrowth increments. Some very fast-growing individuals lived in settings of high production and low temperature. No individuals grew slowly under high production whereas most if not all grew slowly under ‘average’ production and low temperature. In that the rapid growth evidently enabled by high production would have afforded protection from predators, Plio-Pleistocene decline in production was probably contributory to the extinction of C. eboreus. However, the negative impact of low temperature on growth under ‘average’ production suggests that temperature decline played some part.
    • The lived experience of climate change: creating open educational resources and virtual mobility for an innovative, integrative and competence-based track at Masters level

      Wilson, Gordon; Abbott, Dina; De Kraker, Joop; Salgado Perez, Paquita; de Kraker, J.; Van Scheltinga, Catharein. Terwisscha; University of Derby (Inderscience Publishers, 2012-05-29)
      This paper explores a new integrative approach to climate change education at Masters level. Drawing on the authors’ involvement in a European Union Erasmus project, it is argued that the diversity of knowledge(s) on climate change are a source of active/social learning. The wide variety of disciplinary, sectoral and lived experiential (both individual and collective) knowledge(s) are all considered legitimate in this exercise, the aim of which is to construct new interdisciplinary knowledge from their boundary interfaces. We further argue for a corresponding pedagogy based on developing transboundary competences – the ability to engage in social learning and action through communicative engagement across knowledge boundaries. We acknowledge that the challenges for enacting transboundary competence are considerable when it requires mobility across epistemological, even ontological, boundaries. The challenges are further compounded when the communicative engagement across space and time requires virtual mobility which is ICT-enabled. Nevertheless, meeting them is a normative goal, not only for this expanded, integrative approach to climate change education, but also for a global resolution of climate change itself.
    • Lonely heart columns: A novel and entertaining way of teaching students abstract writing skills

      Turner, Ian J.; Beaumont, Ellen S.; University of Derby (Staffordshire University, 2013-04)
      Abstract writing is a key skill for science graduates; they are a common feature in many of the standard forms of scientific dissemination such as scientific research articles. In this paper we present a novel and entertaining approach for teaching abstract writing using adverts from lonely heart columns (LHC). Student constructed full profiles of the authors of LHC and constructed LHC profiles of celebrities to illustrate the key sills in abstract construction. There was no significant difference between the grades achieved by student taught using LHC and a more traditional approach, suggesting there were no negative impacts from this delivery method. Student in LHC tutorial overwhelmingly enjoy the tutorial, 95% responded the question ‘how would you rate the enjoyment of this tutorial’ as ‘much’ or ‘very much’. In addition to abstract writing two thirds of students in LHC tutorial believed they improved their ability to speak in front of others and their creative thinking skills. The LHC tutorial is a novel approach to teaching and learning that is both enjoyable and effective.
    • Long-term patterns of sleeping site use in wild saddleback (Saguinus fuscicollis) and moustached tamarins (S. mystax): effects of foraging, thermoregulation, predation, and resource defense constraints

      Smith, Andrew C.; Knogge, Christoph; Huck, Maren; Löttker, Petra; Buchanan-Smith, Hannah M.; Heymann, Eckhard W.; German Primate Centre, Göttingen; University of Sussex; Anglia Ruskin University; Umweltforschungszentrum Leipzig-Halle; et al. (2007)
      Sleeping sites are an important aspect of an animal’s ecology given the length of time that they spend in them. The sleep ecology of wild saddleback and mustached tamarins is examined using a long-term data set covering three mixed-species troops and 1,3001 tamarin nights. Seasonal changes in photoperiod accounted for a significant amount of variation in sleeping site entry and exit times. Time of exit was more closely correlated with sunrise than time of entry was with sunset. Both species entered their sleeping sites when light levels were significantly higher than when they left them in the morning. Troops of both species used >80 individual sites, the majority being used once. Mustached tamarins never used the same site for more than two consecutive nights, but addlebacks reused the same site for up to four consecutive nights. mustached tamarins slept at significantly greater heights than saddleback tamarins. There were consistent interspecific differences in the types of sites used. Neither the presence of infants, season, nor rainfall affected the types or heights of sites chosen. Sleeping sites were located in the central area of exclusive use more often than expected, and their position with respect to fruiting trees indicated a strategy closer to that of a multiple central place forager than a central place forager. These findings are discussed in light of species ecology, with particular reference to predation risk, which is indicated as the major factor influencing the pattern of sleeping site use in these species.
    • Long-term salinity tolerance is accompanied by major restructuring of the coral bacterial microbiome.

      Röthig, Till; Ochsenkühn, Michael A.; Roik, Anna; van der Merwe, Riaan; Voolstra, Christian R.; King Abdullah University of Science and Technology (KAUST); Red Sea Research Center; King Abdullah University of Science and Technology (KAUST); Thuwal 23955-6900 Saudi Arabia; Biological and Organometallic Catalysis Laboratories; King Abdullah University of Science and Technology (KAUST); Thuwal 23955-6900 Saudi Arabia; Red Sea Research Center; King Abdullah University of Science and Technology (KAUST); Thuwal 23955-6900 Saudi Arabia; Red Sea Research Center; King Abdullah University of Science and Technology (KAUST); Thuwal 23955-6900 Saudi Arabia; et al. (Wiley., 2016-02-03)
      Scleractinian corals are assumed to be stenohaline osmoconformers, although they are frequently subjected to variations in seawater salinity due to precipitation, freshwater run-off and other processes. Observed responses to altered salinity levels include differences in photosynthetic performance, respiration and increased bleaching and mortality of the coral host and its algal symbiont, but a study looking at bacterial community changes is lacking. Here, we exposed the coral Fungia granulosa to strongly increased salinity levels in short- and long-term experiments to disentangle temporal and compartment effects of the coral holobiont (i.e. coral host, symbiotic algae and associated bacteria). Our results show a significant reduction in calcification and photosynthesis, but a stable microbiome after short-term exposure to high-salinity levels. By comparison, long-term exposure yielded unchanged photosynthesis levels and visually healthy coral colonies indicating long-term acclimation to high-salinity levels that were accompanied by a major coral microbiome restructuring. Importantly, a bacterium in the family Rhodobacteraceae was succeeded by Pseudomonas veronii as the numerically most abundant taxon. Further, taxonomy-based functional profiling indicates a shift in the bacterial community towards increased osmolyte production, sulphur oxidation and nitrogen fixation. Our study highlights that bacterial community composition in corals can change within days to weeks under altered environmental conditions, where shifts in the microbiome may enable adjustment of the coral to a more advantageous holobiont composition.
    • Looking beyond the visible: contesting environmental agendas for Mumbai slums

      Abbott, Dina; University of Derby, Department of Development Geography (Oxford University Press, 2009)
      Slums are the most immediate, visible symbols of poverty and environmental degra-dation intertwined in cities. They are a constant reminder of national shame and the state’s incapacity or political will to tackle poverty. In cities where the poor and rich share spaces, the rich will attempt to mentally and morally distance themselves from the slums, often regarding these as eyesores, health hazards, and dens of corruption and immoral behaviour. Yet slums are home to millions, from single householders to intergenerational extended families. Within each slum locality, there is intense social networking to safe¬guard common interest, provide informal services for neighbours and enhance the ability to carry out livelihood opportunities. There is a clear contrast in the way slums are regarded by ‘outsiders’, and those who actually live there. Equally there is a difference in which both outsiders and slum dwellers understand environmental needs. A key question for this chapter is, therefore, what is the contested nature of environ-mental agendas in urban areas and who or what defines it? This chapter draws on Mumbai as an example to argue that within shared spaces, whilst there may be commonality of environmental interests, environmental agendas are often shaped by those who are more powerful and vocal.
    • Low genetic variability, female-biased dispersal and high movement rates in an urban population of Eurasian badgers Meles meles

      Huck, Maren; Frantz, Alain C.; Dawson, Deborah A.; Burke, Terry; Roper, Timothy J.; University of Sussex; University of Sheffield (Wiley, 2008)
      1. Urban and rural populations of animals can differ in their behaviour, both in order to meet their ecological requirements and due to the constraints imposed by different environments. The study of urban populations can therefore offer useful insights into the behavioural flexibility of a species as a whole, as well as indicating how the species in question adapts to a specifically urban environment. 2. The genetic structure of a population can provide information about social structure and movement patterns that is difficult to obtain by other means. Using non-invasively collected hair samples, we estimated the population size of Eurasian badgers Meles meles in the city of Brighton, England, and calculated population-specific parameters of genetic variability and sex-specific rates of outbreeding and dispersal. 3. Population density was high in the context of badger densities reported throughout their range. This was due to a high density of social groups rather than large numbers of individuals per group. 4. The allelic richness of the population was low compared with other British populations. However, the rate of extra-group paternity and the relatively frequent (mainly temporary) intergroup movements suggest that, on a local scale, the population was outbred. Although members of both sexes visited other groups, there was a trend for more females to make intergroup movements. 5. The results reveal that urban badgers can achieve high densities and suggest that while some population parameters are similar between urban and rural populations, the frequency of intergroup movements is higher among urban badgers. In a wider context, these results demonstrate the ability of non-invasive genetic sampling to provide information about the population density, social structure and behaviour of urban wildlife.
    • Low temperature, authigenic illite and carbonates in a mixed dolomite-clastic lagoonal and pedogenic setting, Spanish Central System, Spain

      Huggett, Jennifer; Cuadros, Javier; Gale, Andrew S.; Wray, David; Adetunji, Jacob; Natural History Museum; University of Portsmouth; University of Greenwich; University of Derby (Elsevier, 2016-06-30)
      The aim of this study was to further our understanding of the pedogenic and lacustrine modification of clay minerals. Some of these modifications are of special interest because they constitute reverse weathering reactions, rare in surface environments, and because there is not yet an accurate assessment of their global relevance in mineralogical and geochemical cycles. For this study, two sections from the Central System in Spain were selected. Both are sections through the Uppper Cenomanian-Turonian mixed clastic and carbonate succession, containing both calcite and dolomite, in the Sierra de Guadarrama. Mid-Turonian sea level fall resulted in the formation of a coastal plain environment in which extensive pedogenesis occurred around saline lagoons. The mineralogical changes that have occurred as a result of sedimentation in saline lagoons and as a consequence of pedogenesis are described. Textural relationships indicate that the dolomite cement pre-dates the calcite. Silicate minerals are represented by quartz, kaolinite, illite-smectite, illite, minor plagioclase and alkali feldspar, and trace chlorite and palygorskite. There is a positive correlation between the intensity of pedogenesis and the proportion of illite in the clay assemblage in one of the sections, indicating pedogenic illitisation. In this section, the intensity of the illitisation process increases up, reaching a maximum where pedogenesis is most intense in the middle part, and then decreases as marine influence increases towards the top of the Alcorlo Formation and the overlying marine Tranquera Formation. The clay assemblages are consistent with a slow transformation process from kaolinite to illite by way of illite-smectite, taking place under surface conditions. The illitisation process has resulted in a less Fe-rich, more Mg-, and Al-rich illite than the majority of previously documented cases in the near surface. Formation of Al-rich illite is not therefore restricted to the deep subsurface. The mechanism for low temperature illitisation involves enhanced layer charge resulting from Mg2 + substitution for Al3 + (or Fe3 +) and Fe3 + to Fe2 + reduction. Mg2 + enrichment may have occurred principally in saline lagoons or lakes, while Fe3 + to Fe2 + reduction occurred as a result of wetting and drying in a pedogenic environment. So far as it has been possible to establish, this dual mechanism has not previously been documented. This study indicates clearly that the dolomite and calcite are authigenic cements that precipitated in a clastic sediment, probably soon after deposition. Dolomitisation and Mg enrichment of the clay may have occurred at the same time. Seawater is the most probable source of Mg.
    • Lower crustal heterogeneity and fractional crystallisation control evolution of small volume magma batches at ocean island volcanoes (Ascension Island, South Atlantic)

      Chamberlain, Katy J.; Barclay, Jenni; Preece, Katie; Brown, Richard J.; Davidson, Jon P.; Durham University; University of Derby; University of East Anglia; Swansea University (Oxford University Press, 2019-08-10)
      Ocean island volcanoes erupt a wide range of magmatic compositions via a diverse range of eruptive styles. Understanding where and how these melts evolve is thus an essential component in the anticipation of future volcanic activity. Here we examine the role of crustal structure and magmatic flux in controlling the location, evolution and ultimately composition of melts at Ascension Island. Ascension Island, in the south Atlantic, is an ocean island volcano which has produced a continuum of eruptive compositions from basalt to rhyolite in its 1-million-year subaerial eruptive history. Volcanic rocks broadly follow a silica undersaturated subalkaline evolutionary trend and new data presented here show a continuous compositional trend from basalt through trachyte to rhyolite. Detailed petrographic observations are combined with in-situ geochemical analyses of crystals and glass, and new whole rock major and trace element data from mafic and felsic pyroclastic and effusive deposits that span the entire range in eruptive ages and compositions found on Ascension Island. These data show that extensive fractional crystallisation is the main driver for the production of felsic melt for Ascension Island; a volcano built on thin, young, oceanic crust. Strong spatial variations in the compositions of erupted magmas reveals the role of a heterogeneous lower crust: differing degrees of interaction with a zone of plutonic rocks are responsible for the range in mafic lava composition, and for the formation of the central and eastern felsic complexes. A central core of nested small-scale plutonic, or mush-like, bodies inhibits the ascent of mafic magmas, allowing sequential fractional crystallisation within the lower crust, and generating felsic magmas in the core of the island. There is no evidence for magma mixing preserved in any of the studied eruptions, suggesting that magma storage regions are transient, and material is not recycled between eruptions.
    • Madagascar's escape from Africa: A high-resolution plate reconstruction for the Western Somali Basin and implications for supercontinent dispersal

      Phethean, Jordan; Kalnins, Lara M.; van Hunen, Jeroen; Biffi, Paolo G.; Davies, Richard J.; McCaffrey, Ken J.W.; Durham University; University of Edinburgh; S.G.E.G ENI, Milan, Italy; Newcastle University (American Geophysical Union (AGU), 2016-12-29)
      Accurate reconstructions of the dispersal of supercontinent blocks are essential for testing continental breakup models. Here, we provide a new plate tectonic reconstruction of the opening of the Western Somali Basin during the breakup of East and West Gondwana. The model is constrained by a new comprehensive set of spreading lineaments, detected in this heavily sedimented basin using a novel technique based on directional derivatives of free‐air gravity anomalies. Vertical gravity gradient and free‐air gravity anomaly maps also enable the detection of extinct mid‐ocean ridge segments, which can be directly compared to several previous ocean magnetic anomaly interpretations of the Western Somali Basin. The best matching interpretations have basin symmetry around the M0 anomaly; these are then used to temporally constrain our plate tectonic reconstruction. The reconstruction supports a tight fit for Gondwana fragments prior to breakup, and predicts that the continent‐ocean transform margin lies along the Rovuma Basin, not along the Davie Fracture Zone (DFZ) as commonly thought. According to our reconstruction, the DFZ represents a major ocean‐ocean fracture zone formed by the coalescence of several smaller fracture zones during evolving plate motions as Madagascar drifted southwards, and offshore Tanzania is an obliquely rifted, rather than transform, margin. New seismic reflection evidence for oceanic crust inboard of the DFZ strongly supports these conclusions. Our results provide important new constraints on the still enigmatic driving mechanism of continental rifting, the nature of the lithosphere in the Western Somali Basin, and its resource potential.
    • Maintaining natural spawning timing in Acropora corals following long distance inter-continental transportation.

      Craggs, Jamie; Guest, James R.; Brett, Aaron; Davis, Michelle; Sweet, Michael J.; University of Derby; Horniman Museum and Gardens; Newcastle University; SECORE Internationa; S.E.A Aquarium (European Association of Zoos and Aquaria, 2018-04-30)
      The majority of research focusing on coral reproductive biology (e.g. spawning timing and synchrony) is carried out in facilities adjacent to reefs that the corals originated from. This is in part because transporting corals for long distances by air leads to sub-lethal stress that may confound the results of any experimental study. However, these constraints often mean research associated with coral reproductive timing is restricted to relatively few locations. To assess the potential for studying environmental drivers of spawning timing in corals in captivity (defined here as ex situ closed aquaria), we aimed to transport 14 large (16-37 cm) Acropora hyacinthus colonies from reefs in Singapore to a closed aquarium system in London (a journey time of ~34 hours). Collection was purposefully timed to occur just before the predicted annual mass spawning event and on the day of transportation it was noted that 12 of the 14 corals contained large visible oocytes. The ‘inverted submersion method’ was applied and the water used for transport was buffered to ensure the colonies remained healthy throughout their travel time. At the end location all colonies were placed into a purpose built aquarium research system which allowed for the approximation of the environmental conditions found on the fringing reefs south of Singapore (the original location). While three colonies appeared partially bleached (visibly pale) and one colony suffered from partial tissue loss, all colonies (i.e. 100% of those collected) were still alive at the time of writing (28 months post collection). More importantly, all corals that were gravid at the time of collection spawned ex situ within the same lunar month as those in the wild (within 3-4 nights of each other). This paper describes the procedures for carrying out long distance transportation of large gravid broadcast spawning coral colonies from reef sites to public aquariums or research facilities around the world for the purpose of ex situ spawning research.
    • Maintaining natural spawning timing in Acropora corals following long distance inter-continental transportation.

      Craggs, Jamie; Guest, James R.; Brett, Aaron; Davis, Michelle; Sweet, Michael J.; University of Derby; Horniman Museum and Gardens; Newcastle University; SECORE International, Inc.; Resorts World Sentosa (European Association of Zoos and Aquaria, 2018-04-29)
      The majority of research focusing on coral reproductive biology (e.g. spawning timing and synchrony) is carried out in facilities adjacent to reefs that the corals originated from. This is in part because transporting corals for long distances by air leads to sub-lethal stress that may confound the results of any experimental study. However, these constraints often mean research associated with coral reproductive timing is restricted to relatively few locations. To assess the potential for studying environmental drivers of spawning timing in corals in captivity (defined here as ex situ closed aquaria), we aimed to transport 14 large (16-37 cm) Acropora hyacinthus colonies from reefs in Singapore to a closed aquarium system in London (a journey time of ~34 hours). Collection was purposefully timed to occur just before the predicted annual mass spawning event and on the day of transportation it was noted that 12 of the 14 corals contained large visible oocytes. The ‘inverted submersion method’ was applied and the water used for transport was buffered to ensure the colonies remained healthy throughout their travel time. At the end location all colonies were placed into a purpose built aquarium research system which allowed for the approximation of the environmental conditions found on the fringing reefs south of Singapore (the original location). While three colonies appeared partially bleached (visibly pale) and one colony suffered from partial tissue loss, all colonies (i.e. 100% of those collected) were still alive at the time of writing (28 months post collection). More importantly, all corals that were gravid at the time of collection spawned ex situ within the same lunar month as those in the wild (within 3-4 nights of each other). This paper describes the procedures for carrying out long distance transportation of large gravid broadcast spawning coral colonies from reef sites to public aquariums or research facilities around the world for the purpose of ex situ spawning research.
    • Major evolutionary transitions of life, metabolic scaling and the number and size of mitochondria and chloroplasts.

      Okie, J.; Smith, V.; Martin-Cereceda, M; University of Kansas, USA; University of Madrid, Spain; Arizona State University, Tempe, AZ, USA (The Royal Society Publishing, 2016-05-25)
      We investigate the effects of trophic lifestyle and two types of major evolutionary transitions in individuality—the endosymbiotic acquisition of organelles and development of multicellularity—on organellar and cellular metabolism and allometry. We develop a quantitative framework linking the size and metabolic scaling of eukaryotic cells to the abundance, size and metabolic scaling of mitochondria and chloroplasts and analyse a newly compiled, unprecedented database representing unicellular and multicellular cells covering diverse phyla and tissues. Irrespective of cellularity, numbers and total volumes of mitochondria scale linearly with cell volume, whereas chloroplasts scale sublinearly and sizes of both organelles remain largely invariant with cell size. Our framework allows us to estimate the metabolic scaling exponents of organelles and cells. Photoautotrophic cells and organelles exhibit photosynthetic scaling exponents always less than one, whereas chemoheterotrophic cells and organelles have steeper respiratory scaling exponents close to one. Multicellularity has no discernible effect on the metabolic scaling of organelles and cells. In contrast, trophic lifestyle has a profound and uniform effect, and our results suggest that endosymbiosis fundamentally altered the metabolic scaling of free-living bacterial ancestors of mitochondria and chloroplasts, from steep ancestral scaling to a shallower scaling in their endosymbiotic descendants.
    • Male genital titillators and the intensity of post-copulatory sexual selection across bushcrickets

      Lehmann, Gerlind; Gilbert, James D. J.; Vahed, Karim; Lehmann, Arne W.; University of Derby; University of Hull; Humbolt University Berlin (Oxford University Press, 2017-07-10)
      Animal genitalia are diverse and a growing body of evidence suggests that they evolve rapidly under post-copulatory sexual selection. This process is predicted to be more intense in polyandrous species, although there have been very few comparative studies of the relationship between the complexity of genital structures in males and measures of the degree of polyandry. In some bushcricket families, males possess sclerotised copulatory structures known as titillators, which are inserted into the female’s genital chamber and moved rhythmically. Like other genital structures, bushcricket titillators are widely used as important taxonomic characters and show considerable variation across species in structure, shape and the extent to which they are spined. Here, we examine relationships between the presence/absence of titillators, titillator complexity and both mating frequency and the degree of polyandry in bushcrickets, using phylogenetic comparative analyses. Using published sources combined with original observations, data were obtained for the mean level of polyandry, the duration of the male and female sexual refractory periods and the level of complexity of titillators. To analyse data, we fitted phylogenetic generalised least squares models. No significant relationships were found between titillator presence or complexity and either the level of polyandry, duration of the male’s sexual refractory period or the ratio of the female and male sexual refractory periods. The duration of the female’s refractory period, however, was positively associated with titillator presence and negatively associated with titillator complexity. The data therefore partially support the hypothesis that post-copulatory sexual selection drives genital evolution in this taxon.
    • Male gryllus bimaculatus guard females to delay them from mating with rival males and to obtain repeated copulations

      Wynn, Helen; Vahed, Karim; University of Derby (Springer, 2004-01)
      Three hypotheses for the function of postcopulatory mate guarding were tested in the field cricket Gryllus bimaculatus De Geer. The duration of spermatophore attachment was greater in the absence than in the presence of a guarding male. The ejaculate protection hypothesis was, therefore, rejected. The duration of mate guarding was found to be equal to the interval between copulations, supporting the spermatophore renewal hypothesis. In support of the rival exclusion hypothesis, the presence of a guarding male did increase the duration of spermatophore attachment when a rival male was also present. The presence of a guarding male also delayed the female from mating with the rival male. Female mating status had a significant effect on the duration of spermatophore attachment. Females mating for the first time retained the spermatophore for a significantly longer period of time than females that had mated previously.
    • Mammals and their activity patterns in a forest area in the Humid Chaco, northern Argentina

      Huck, Maren; Juarez, Cecilia P.; Rotundo, Marcelo; Dávalos, Victor; Fernandez-Duque, Eduardo; University of Derby; Universidad Nacional de Formosa; Proyecto Mirikiná; Yale University (Pensoft, 2017-08-25)
      The Humid Chaco has a high mammalian biodiversity. As habitats are threatened due to exploitation and environmental degradation, protected areas can act as refuges for wild animals. In 2006, ca 1,100 ha of gallery forest were established as the “Owl Monkey Reserve” within the private cattle ranch “Estancia Guaycoléc”. The mammalian species richness and composition of the reserve was determined using direct observations, camera traps, and indirect evidence. The camera traps also allowed us to determine the activity periods of 20 of the species. Forty-two species were recorded. A fourth of those species (24%) are categorized under some risk of extinction in Argentina. While most species showed usual activity periods, 2 species (Mazama americana and Tayassu pecari) were not as exclusively nocturnal as reported from other sites, possibly due to reduced hunting pressure. The presence of various endangered species highlights the importance of protected private reserves.
    • The many faces of helping: possible costs and benefits of infant carrying and food transfer in wild moustached tamarins (Saguinus mystax)

      Löttker, Petra; Huck, Maren; Heymann, Eckhard W.; Abteilung Soziobiologie, Deutsches Primatenzentrum, Göttingen, Germany; Lehrstuhl für Verhaltensforschung, Universität Bielefeld, Germany; Institut für Neuro- & Verhaltensbiologie, Abt. Verhaltensbiologie, Westfälische Wilhelms-Universität Münster, Germany (2004-07-01)
      Various hypotheses about adaptive and non-adaptive mechanisms of non-parental infant care have been put forward for different taxa (Emlen et al., 1991). The Neotropical callitrichid primates are renowned for their cooperative care of the twin litters. None of the studies conducted in the wild included information on genetic relationships within groups. This, however, is indispensable to evaluate the relevance of competing hypotheses concerning direct or indirect fitness gains. We studied two groups of wild moustached tamarins with known genetic relationships over a one-year period to examine individual time-budgets and contributions to infant carrying and food-transfer. With these data we tested whether helping behaviour might be a non-adaptive trait and, if not, whether indirect benefits via kin-selection could be excluded as an evolutionary force maintaining it. Other hypotheses on direct fitness benefits were discussed as far as (anecdotal) data permitted. Changes in time-budgets suggest costs, thus clearly refuting hypotheses assuming non-adaptivity. High within-group relatedness suggests kin-selection to be one driving force of maintaining the trait. However, non-parental individuals may help despite low relatedness. Data were not sufficient to decide which possible direct benefits most likely play a role in inducing non-relatives to help. Yet, two (non-exclusive) explanations seem to be the most probable ones: The chance to inherit the main-breeding position, and a certain chance of own direct reproductive success (the latter only for male helpers) due to polyandrous mating by the female. Other adaptive mechanisms may enhance benefits but are unlikely to be major selective forces since fitness gains are presumably rather small or uncertain.