Browsing by UP Author "Kohler, Angela"

Browsing by UP Author "Kohler, Angela"

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  • Antioxidant supplementation can reduce the survival costs of excess amino acid intake in honeybees 
    Archer, C. Ruth; Kohler, Angela; Pirk, Christian Walter Werner; Oosthuizen, Vinette; Apostolides, Zeno; Nicolson, Sue W. (Elsevier, 2014-12)
    Over-consuming amino acids is associated with reduced survival in many species, including honeybees. The mechanisms responsible for this are unclear but one possibility is that excessive intake of amino acids increases ...
  • Coloured and toxic nectar : feeding choices of the Madagascar giant day gecko, Phelsuma grandis 
    Minnaar, I.A. (Ingrid Ane); Kohler, Angela; Purchase, Cromwell; Nicolson, Sue W. (Wiley-Blackwell, 2013-05)
    Coloured nectar is a rare phenomenon best known from islands and insular habitats. Islands are also known for lizard pollination, where coloured nectar potentially acts as a visual cue to attract pollinators, advertising ...
  • Honeybees and nectar nicotine : deterrence and reduced survival versus potential health benefits 
    Kohler, Angela; Pirk, Christian Walter Werner; Nicolson, Sue W. (Elsevier, 2012)
    Secondary metabolites produced by plants for herbivore defence are often found in floral nectar, but their effect on the foraging behaviour and physiological performance of pollinators is largely unknown. Nicotine is ...
  • Honeybees prefer warmer nectar and less viscous nectar, regardless of sugar concentration 
    Nicolson, Sue W.; De Veer, Leo; Kohler, Angela; Pirk, Christian Walter Werner (The Royal Society, 2013-09)
    The internal temperature of flowers may be higher than air temperature, and warmer nectar could offer energetic advantages for honeybee thermoregulation, as well as being easier to drink owing to its lower viscosity. We ...
  • Miscellaneous standard methods for Apis mellifera 
    Human, Hannelie; Brodschneider, Robert; Dively, Galen; Ellis, James D.; Forsgren, Eva; Fries, Ingemar; Hatjina, Fani; Hu, Fu-Liang; Jaffe, Rodolfo; Jensen, Annette Bruun; Kohler, Angela; Magyar, Josef P.; Ozkyrym, Asli; Pirk, Christian Walter Werner; Rose, Robyn; Strauss, Ursula; Tanner, Gina; Tarpy, David R.; Van der Steen, Jozef J.M.; Vaudo, Anthony; Vejsnæs, Fleming; Wilde, Jerzy; Williams, Geoffrey R.; Zheng, Huo-Qing (International Bee Research Association, 2013-05-09)
    A variety of methods are used in honey bee research and differ depending on the level at which the research is conducted. On an individual level, the handling of individual honey bees, including the queen, larvae and pupae ...
  • A new design for honey bee hoarding cages for laboratory experiments 
    Kohler, Angela; Nicolson, Sue W.; Pirk, Christian Walter Werner (International Bee Research Association, 2013)
    Honey bees are the subject of research around the world due to their great economic importance and current population declines (vanEngelsdorp and Meixner, 2010). Many studies cannot be conducted at the colony level. ...
  • A new design for honeybee hoarding cages for laboratory experiments 
    Kohler, Angela; Nicolson, Sue W.; Pirk, Christian Walter Werner (Pretoria: University of Pretoria. Faculty of Natural and Agricultural Sciences. Department of Zoology & Entomology, 2012)
  • Regulation of nutrient intake in nectar-feeding birds : insights from the geometric framework 
    Kohler, Angela; Raubenheimer, David; Nicolson, Sue W. (Springer, 2012-07)
    A nectar diet is simple in nutritional composition and easily digested, but may vary greatly in its proportions of sugar and water. Here, we apply the geometric framework, a modelling approach for investigating how ...
  • Simultaneous stressors : interactive effects of an immune challenge and dietary toxin can be detrimental to honeybees 
    Kohler, Angela; Pirk, Christian Walter Werner; Nicolson, Sue W. (Pretoria: University of Pretoria. Faculty of Natural and Agricultural Sciences. Department of Zoology & Entomology, 2012)
    Recent large-scale mortality of honeybee colonies is believed to be caused by multiple interactions between diseases, parasites, pesticide exposure, and other stress factors. To test whether a dual challenge has an additive ...
  • Sunbirds increase foraging success by using color as a cue for nectar quality 
    Whitfield, Maxine; Kohler, Angela; Nicolson, Sue W. (Oxford University Press, 2014-03)
    Nectar concentration and composition varies widely between plant species. Nectarivorous birds that associate floral characteristics with nectar quality may be able to avoid less rewarding flowers and therefore forage ...