Proceedings of The Royal Society B: Biological Sciences
Management of genetically modified herbicide tolerant sugar beet for spring and autumn environmental benefit by Dr M May, Dr G Champion, Dr A Dewar, Dr A Qi and Dr J Pidgeon
This research provides conclusive evidence that environmental benefits can be obtained from GM herbicide tolerant (GMHT) sugar beet crops. Previous work, including the government's Farm Scale Evaluation trials, suggested that GMHT sugar beet, whilst providing environmental benefits early in the season, will reduce weed seed numbers in late season, depriving birds of autumn food sources. Our new work on herbicide timing shows that single glyphosate applications can increase yields, and enhance weed seed production up to sixteen fold compared to conventional systems. These changes to GM crop management enable farmers to reduce herbicide use and costs, whilst satisfying public demands for increasing benefits to wildlife.
Contact: Dr Mike May, Rothamstead Research, Broom's Barn, Higham, SUFFOLK, IP28 6NP, United Kingdom
Cellular fine structures and histochemical reactions in the tissue of a cypress twig preserved in Baltic amber by Dr B Koller, Dr JM Schmitt and Dr G Tischendorf
Plants and insects, enshrined in Baltic amber for 40-50 million years, often display a remarkable degree of structural conservation on the surface. In this study the preservation of the inside of an amber inclusion was examined. Sections of a Cypress twig were analysed by light and electron microscopy. An almost intact tissue was revealed, comparable to related extant plants. The fine structures of cells are preserved and intact chloroplasts and mitochondria are visible. The ultrastructure of membranes and cell walls can be recognized. Interaction of the tissue with cytological stains is comparable with those of living plants. The cuticle displays a strong autofluorescence under UV light.
Contact: Dr Barbara Koller, Institut fur Biologie Freie, Universitat Berlin, Konigin-Luisestr. 12-16, BERLIN, D-14195, Germany
Evolution of juvenile growth rates in female guppies (Poecilia reticulata): predator regime or resource level by Dr J Arendt and Professor DN Reznick
Two factors driving evolution in guppies are predation (some populations have large predators that eat guppies of all size, some have small predators that only eat small guppies) and food level. We compared guppies taken from high predation and low predation to determine whether size-limited predation or food level had a greater impact on the evolution of growth rate. The small predator, low food populations usually grew slower than the large predator, high food populations suggesting local food levels, not predation pressure, drive the evolution of growth rate in guppies.
Contact: Dr Jeffrey Arendt, Biology Department, University of California at Riverside, RIVERSIDE, CA 92521, USA
Metabolic profile of long-distance migratory flight and stopover in a shorebird by Dr MM Landys, Dr T Piersma, Dr CG Guglielmo, Dr J Jukema, Dr M Ramenofsky and Professor JC Wingfield
Migrating birds often complete long non-stop flights during which body energy stores exclusively support energetic demands. To determine the energy fuels associated with such extended activity, we evaluated plasma concentrations of six key energy metabolites in bar-tailed godwits (Limosa lapponica taymyrensis) caught immediately upon landing after a non-stop migratory flight of 4,500-km. Metabolite data confirm the importance of lipids in fuelling long-distance flight and show that protein breakdown significantly contributes to the support of endurance travel. Furthermore, results indicate that lipid provisioning through fatty acid circulation is supplemented by plasma triglycerides – a pathway previously hypothesized to apply only to small migrants.
Contact: Dr Meta Landys, Department of Biology, University of Oslo, PO Box 1050, OSLO, N-0316, Norway
Sperm influences female hibernation success, survival and fitness in the bumble-bee Bombus terrestris by Dr B Baer and Professor P Schmid-Hempel
An unresolved problem in biology is why females mate with several males. Bumblebee colonies would benefit from queens mating multiply because genetically heterogeneous worker offspring are better protected against parasitism. However, as we show, possessing sperm from several males can have negative effects on females. We artificially inseminated females with sperm only from either a single or several males to avoid any direct contact between the sexes. Females receiving sperm from several males were more likely to die during hibernation, survived shorter periods and produced less offspring than females receiving sperm from a single male. Furthermore, sperm from some males (brothers) are more costly for females than others.
Contact: Dr Boris Baer, Biological Institute, Department of Population Biology, Universitetsparken 15, University of Copenhagen, 2100 Copenhagen, Denmark
Tasting the difference: do multiple defence chemicals interact in Müllerian mimicry? By Dr J Skelhorn and Dr CL Rowe Müllerian mimicry is where two unpalatable prey species share a similar colour signal that predators learn to avoid. Although mimics may look remarkably similar, the chemicals that render them unpalatable may be very different. This study found that birds learned to avoid mimics more quickly, and avoided them for longer, when they possessed different chemicals than when they shared the same chemical. As a result, mimics that share the same defence chemicals may suffer heavier predation which may help to explain why unpalatable insects utilize a wide variety of different defence chemicals in nature.
Contact: Dr John Skelhorn, School of Biology, University of Newcastle, Henry Wellcome Building, NEWCASTLE, NE2 4HH, United Kingdom
On estimating the number of species from the discovery record by Dr AR Solow and Professor WK Smith
A central question in biology concerns the number of species in a taxonomic or other group. A common approach to estimating the number of species in a taxonomic or other group is to extrapolate the historical rate at which species have been discovered. To date, this has been done in an informal way. This paper presents the first formal statistical approach to this problem. The approach is applied to the discovery record of large marine animals over the period 1828-1996. By the end of this period, a total of 217 species had been discovered. The estimated number of undiscovered species is 10.
Contact: Dr Andrew Solow, MPC, Woods Hole Oceanographic Institution, MS 41, WOODS HOLE, MA 02543, United States
Helpers in a cooperatively breeding cichlid stay and pay or disperse and breed, depending on ecological constraints by Dr R Bergmüller, Dr D Heg and Professor M Taborsky
Cooperative breeding, ie when subordinates help to raise offspring of dominants, is widely assumed to be a 'best of a bad job' strategy. Consequently helpers should reduce cooperative behaviour and choose to disperse and breed independently in the presence of vacant breeding sites. We found that helpers in the cooperatively breeding cichlid Neolamprologus pulcher reduced help when independent breeding was possible. Mainly large helpers left the group to breed independently. Our study provides experimental evidence that the degree of ecological constraints from dispersing for own breeding influences concurrently two major decisions of helpers: whether to stay and how much to help.
Contact: Dr Ralph Bergmüller, Behavioural Ecology, University of Bern, Ethologische Station Hasli, HINTERKAPPELEN, CH-3032, Switzerland
Proceedings of The Royal Society A: Mathematical, Physical and Engineering Sciences
Inertia law for spectral stability of solitary waves in coupled nonlinear Schrödinger equations by Professor DE Pelinovsky Spectral stability analysis for solitary waves is developed in context of the Hamiltonian system of coupled nonlinear Schrödinger equations. The linear eigenvalue problem for a non-self-adjoint operator is studied with two self-adjoint matrix Schrödinger operators. Sharp bounds on the number and type of unstable eigenvalues in the spectral problem are found from the inertia law for quadratic forms, associated with the two self-adjoint operators.
Contact: Professor Dmitry Pelinovsky, Department of Mathematics, McMaster University, 1280 Main Street West, Hamilton, ONTARIO, L8S 4K1, CANADA
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