Angela Köhler

• research interests

  Plants produce secondary metabolites as a defense against herbivores. I am interested in the effect of defense compounds on insect herbivores, and their role in plant-insect interactions. In the past, I have investigated the effect of nicotine, an alkaloid found in many agricultural crops, on foraging choices and longevity of pollinators. Honeybees tolerated naturally occurring nectar nicotine concentrations, but the dose-dependent deterrent effect of nicotine was found to be stronger in dilute nectars. High nicotine concentrations reduced longevity, but there was some evidence that honeybees may benefit from its antimicrobial properties.
  
  My current project focuses on the role of benzoxazinoid derivatives (BXDs) in maize resistance to above-ground herbivores. Benzoxazinoids are key defensive metabolites in grasses, and I am studying their ecological and behavioral effects on generalist and specialist insect pests (several lepidopteran species, aphids etc). Insect feeding behavior and growth rate on maize lines differing in their BXD levels will reveal the contribution of these metabolites to maize resistance. I determine which BXDs are important for resistance, and to what extent they are responsible for induced resistance. Specialist maize pests may be more tolerant, or even exploit BXDs (host plant recognition, feeding stimulants). I also determine the role of modified BXDs in insect frass and regurgitant as feedback signals for plants. This research is part of an interdisciplinary approach, the Sinergia project, and will contribute to our understanding of plant-herbivore interactions.

• publications

  PUBLICATIONS

  Köhler A, Maag D, Veyrat N, Glauser G, Wolfender J-L, Turlings TCJ & Erb M. 2014. Within-plant distribution of 1,4-benzoxazin-3-ones contributes to herbivore niche differentiation in maize. Plant, Cell & Environment, DOI: 10.1111/pce.12464.

  Archer CR, Köhler A, Pirk CWW, Oosthuizen V, Apostolides Z & Nicolson SW. 2014. Antioxidant supplementation can reduce the survival costs of excess amino acid intake in honeybees. Journal of Insect Physiology, DOI: 10.1016/j.insphys.2014.10.006.

  Maag D, Dalvit C, Thevenet D, Köhler A, Wouters FC, Vassão DG, Gershenzon J, Wolfender J-L, Turlings TCJ, Erb M & Glauser G. 2014. 3-ß-D-Glucopyranosyl-6-methoxy-2-benzoxazolinone (MBOA-N-Glc) is an insect detoxification product of maize 1,4-benzoxazin-3-ones. Phytochemistry 102: 97-105.

  Whitfield M, Köhler A & Nicolson SW. 2014. Sunbirds increase foraging success by using color as a cue for nectar quality. Behavioral Ecology 25(2): 328-334.

  Human H, Brodschneider R, Dietemann V, Dively G, Ellis J, Forsgren E, Fries I, Hatjina F, Hu F-L, Jaffé R, Jensen AB, Köhler A, Magyar J, Özikrim A, Pirk CWW, Rose R, Strauss U,  Tanner G, Tarpy DR, Van Der Steen JJM, Vaudo A, Vejsnæs F, Wilde J, Williams GR & Zheng H-Q. 2013. Miscellaneous standard methods for Apis mellifera research. In: Dietemann V, Ellis JD, Neumann P (Eds) The COLOSS BEEBOOK, Volume I: standard methods for Apis mellifera research. Journal of Apicultural Research 52(4): 1-55.

  Nicolson SW, de Veer L, Köhler A & Pirk CWW. 2013. Honeybees prefer warmer nectar and less viscous nectar, regardless of sugar concentration. Proceedings of the Royal Society B 280: 20131597 .

  Köhler A , Nicolson SW & Pirk CWW. 2013. A new design for honey bee hoarding cages for laboratory experiments. Journal of Apicultural Research 52(2): 12–14.

  Minnaar IA, Köhler A, Purchase C & Nicolson SW. 2013. Coloured and toxic nectar: feeding choices of the Madagascar giant day gecko, Phelsuma grandis . Ethology 119 : 417 –426.

  Köhler A , Pirk CWW & Nicolson SW. 2012. Simultaneous stressors: interactive effects of an immune challenge and dietary toxin can be detrimental to honeybees. Journal of Insect Physiology 58: 918–923.

  Köhler A , Raubenheimer D & Nicolson SW. 2012. Regulation of nutrient intake in nectar-feeding birds: insights from the geometric framework. Journal of Comparative Physiology B 182: 603–611.

  Köhler A , Pirk CWW & Nicolson SW. 2012. Honeybees and nectar nicotine: deterrence and reduced survival versus potential health benefits. Journal of Insect Physiology 58: 286–292.

  Mann O, Lieberman V, Köhler A, Korine C, Hedworth H & Voigt-Heucke SL. 2011. Finding your friends at densely populated roosting places: can male Egyptian fruit bats (Rousettus aegyptiacus) distinguish between familiar and unfamiliar conspecifics? Acta Chiropterologica 13: 411–417.

  Köhler A , Verburgt L, Fleming PA, McWhorter TJ & Nicolson SW. 2011. Interruptions in nectar availability: can whitebellied sunbirds (Cinnyris talatala) and brown honeyeaters (Lichmera indistincta) cope? Emu 111: 252–258.

  Köhler A , Sadowska J, Olszewska J, Trzeciak P, Berger-Tal O & Tracy CR. 2011. Staying warm or moist? Operative temperature and thermal preferences of common frogs (Rana temporaria), and effects on locomotion. Herpetological Journal 21: 17–26.

  Köhler A , Verburgt L, McWhorter TJ & Nicolson SW. 2010. Energy management on a nectar diet: can sunbirds meet the challenges of low temperature and dilute food? Functional Ecology 24: 1241–1251.

  Köhler A , Leseigneur CDC, Verburgt L & Nicolson SW. 2010. Dilute bird nectars: viscosity constrains food intake by licking in a sunbird. American Journal of Physiology (Regul Integr Comp Physiol) 299: R1068–R1074.

  Köhler A , Verburgt L & Nicolson SW. 2008. Nectar intake of whitebellied sunbirds (Cinnyris talatala): can meal size be inferred from feeding duration? Physiological and Biochemical Zoology 81: 682–687.

  Köhler A , Verburgt L, Fleming PA & Nicolson SW. 2008. Changes in nectar concentration: how quickly do whitebellied sunbirds (Cinnyris talatala) adjust feeding patterns and food intake? Journal of Comparative Physiology B 178: 785–793.

  Köhler A , Verburgt L & Nicolson SW. 2006. Short-term energy regulation of whitebellied sunbirds (Nectarinia talatala): effects of food concentration on feeding frequency and duration. Journal of Experimental Biology 209: 2880–2887.

   

  POSTERS AND PRESENTATIONS

  Presentation: Köhler A, Pirk CWW & Nicolson SW. Toxic nectar: effects of nicotine on honeybees. 15th Symposium on Insect-Plant Interactions, Neuchâtel, Switzerland (Aug 2014)

  Presentation: Köhler A, Pirk CWW & Nicolson SW. Nutritional effects on honeybee longevity and stress resistance. 61. Jahrestagung der AG der Institute für Bienenforschung, Marburg, Germany (Mar2014)

  Poster: Köhler A, Maag D, Glauser G, Erb M, & Turlings TCJ. Do induced benzoaxazinoids mediate spatial feeding patterns of maize herbivores? 32nd New Phytologist Symposium: Plant interactions with other organisms: molecules, ecology and evolution, Buenos Aires, Argentina (Nov 2013)

  Poster: Maag D, Köhler A, Glauser G, Erb M, Wolfender J-L & Turlings TCJ. Leaf herbivore foraging patterns in maize are associated with 1,4-benzoxazinone profiles. IOBC-WPRS Conference on Induced Resistance in Plants, Avignon, France (Jun 2013)

  Poster: Köhler A, Maag D, Glauser G, Turlings TCJ & Erb M. Local induction of chemical defenses in maize: caterpillar responses to within-leaf gradients of benzoxazinoid derivatives. Gordon Research Conference on Plant-Herbivore Interactions, Ventura, California (Feb 2013 )

  Poster: Köhler A, Turlings TCJ & Erb M. Responses of maize to insect herbivores: compensatory growth following leaf attack? Final NCCR Plant Survival Meeting, Neuchâtel, Switzerland (Jan 2013)

  Presentation: Köhler A, Glauser G, Turlings TCJ & Erb M. Responses of generalist and specialist insect herbivores to maize benzoxazinoid derivatives. JSPS Core-to-Core Meeting, MPI Chem. Ecology, Jena, Germany (Oct 2012)

  Poster: Köhler A , Pirk CWW & Nicolson SW. Harmful and beneficial effects of nectar nicotine – a pollinator’s perspective. 9^th Solanaceae Conference, Neuchâtel, Switzerland (Aug 2012)

  Presentation: Köhler A, Pirk CWW & Nicolson SW. ‘Toxic nectar’: harmful and beneficial effects of nicotine on an important pollinator, the African honeybee. 38^th Annual Conference of the South African Association of Botanists, Pretoria, South Africa (Jan 2012)

  Presentation: Köhler A, Pirk CWW & Nicolson SW. ‘Toxic nectar’: nicotine has both harmful and beneficial effects on honeybees. Annual Main Meeting of the Society for Experimental Biology, Glasgow, Scotland (Jul 2011)

  Presentation: Köhler A, Raubenheimer D & Nicolson SW. Energy and water regulation in avian nectarivores: insights from the Geometric Framework. 5^th American Physiological Society Meeting, Denver, Colorado (Aug 2010)

  Presentation: Köhler A , Verburgt L, McWhorter TJ, Fleming PA & Nicolson SW. Effects of energy challenges on food intake and body mass of sunbirds (Nectariniidae) and honeyeaters (Meliphagidae). 50^th Anniversary Conference of the Zoological Society of Southern Africa, Illovo Beach, South Africa (Jul 2009)

  Poster: Köhler A, Verburgt L, Fleming PA, McWhorter TJ & Nicolson SW. Interruptions to a sweet life: the responses of two avian nectarivores to a fasting period. 4^th Int. Conference in Africa for Comparative Physiology & Biochemistry, Maasai Mara, Kenya (Jul 2008)

  Presentation: Köhler A , Verburgt L, Fleming PA & Nicolson SW. Acute changes in nectar concentration: how quickly do whitebellied sunbirds (Cinnyris talatala) adjust their food intake? 4^th Biennial Australasian Ornithological Conference, Perth, Western Australia (Dec 2007)

  Presentation: Köhler A , Verburgt L, Fleming PA & Nicolson SW. How do acute changes in nectar concentration affect food intake of whitebellied sunbirds (Cinnyris talatala)? 33^rd Congress of the Zoological Society of Southern Africa, Potchefstroom, South Africa (Jul 2007)