Steven D Johnson

Summary

Affiliation: University of Natal
Country: South Africa

Publications

  1. pmc Evolutionary associations between nectar properties and specificity in bird pollination systems
    Steven D Johnson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, Republic of South Africa
    Biol Lett 4:49-52. 2008
  2. pmc The effects of nectar addition on pollen removal and geitonogamy in the non-rewarding orchid Anacamptis morio
    Steven D Johnson
    School of Botany and Zoology, University of KwaZulu Natal, Post Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Proc Biol Sci 271:803-9. 2004
  3. doi Evolution and coexistence of pollination ecotypes in an African Gladiolus (Iridaceae)
    Bruce Anderson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01 Scottsville, Pietermaritzburg, 3209, South Africa
    Evolution 64:960-72. 2010
  4. doi Emasculation increases seed set in the bird-pollinated hermaphrodite Kniphofia linearifolia (Xanthorrhoeaceae): evidence for sexual conflict?
    Karl J Duffy
    School of Life Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Am J Bot 100:622-7. 2013
  5. ncbi Mechanisms and evolution of deceptive pollination in orchids
    Jana Jersáková
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Pietermaritzburg, 3209, South Africa
    Biol Rev Camb Philos Soc 81:219-35. 2006
  6. ncbi Phylogenetic evidence for pollinator-driven diversification of angiosperms
    Timotheüs van der Niet
    School of Life Sciences, University of KwaZulu Natal, P Bag X01, Scottsville 3209, South Africa
    Trends Ecol Evol 27:353-61. 2012
  7. doi Geographical covariation and local convergence of flower depth in a guild of fly-pollinated plants
    Bruce Anderson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, P Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    New Phytol 182:533-40. 2009
  8. pmc The missing stink: sulphur compounds can mediate a shift between fly and wasp pollination systems
    Adam Shuttleworth
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Proc Biol Sci 277:2811-9. 2010
  9. pmc Relationships between population size and pollen fates in a moth-pollinated orchid
    Steven D Johnson
    School of Biological and Conservation Sciences, University of Kwa, Zulu NatalScottsville, Pietermaritzburg 3209, South Africa
    Biol Lett 5:282-5. 2009
  10. pmc Carrion mimicry in a South African orchid: flowers attract a narrow subset of the fly assemblage on animal carcasses
    Timotheüs van der Niet
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Scottsville, Pietermaritzburg, South Africa
    Ann Bot 107:981-92. 2011

Detail Information

Publications44

  1. pmc Evolutionary associations between nectar properties and specificity in bird pollination systems
    Steven D Johnson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, Republic of South Africa
    Biol Lett 4:49-52. 2008
    ..We present several hypotheses for the association between nectar properties and specificity in bird pollination systems...
  2. pmc The effects of nectar addition on pollen removal and geitonogamy in the non-rewarding orchid Anacamptis morio
    Steven D Johnson
    School of Botany and Zoology, University of KwaZulu Natal, Post Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Proc Biol Sci 271:803-9. 2004
    ..These findings provide empirical support both for Darwin's contention that pollinarium bending is an anti-selfing mechanism in orchids and for the idea that floral deception serves to maximize the efficiency of pollen export...
  3. doi Evolution and coexistence of pollination ecotypes in an African Gladiolus (Iridaceae)
    Bruce Anderson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01 Scottsville, Pietermaritzburg, 3209, South Africa
    Evolution 64:960-72. 2010
    ..Positive directional selection on tube length was found to occur in both morphs...
  4. doi Emasculation increases seed set in the bird-pollinated hermaphrodite Kniphofia linearifolia (Xanthorrhoeaceae): evidence for sexual conflict?
    Karl J Duffy
    School of Life Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Am J Bot 100:622-7. 2013
    ....
  5. ncbi Mechanisms and evolution of deceptive pollination in orchids
    Jana Jersáková
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Pietermaritzburg, 3209, South Africa
    Biol Rev Camb Philos Soc 81:219-35. 2006
    ....
  6. ncbi Phylogenetic evidence for pollinator-driven diversification of angiosperms
    Timotheüs van der Niet
    School of Life Sciences, University of KwaZulu Natal, P Bag X01, Scottsville 3209, South Africa
    Trends Ecol Evol 27:353-61. 2012
    ..Despite technical advances, phylogenies remain limited in their power to distinguish among various pollinator-driven evolutionary processes...
  7. doi Geographical covariation and local convergence of flower depth in a guild of fly-pollinated plants
    Bruce Anderson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, P Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    New Phytol 182:533-40. 2009
    ..Thus, rarer and nonrewarding species in the guild are forced to keep pace with the coevolutionary race between common rewarding flowers and flies...
  8. pmc The missing stink: sulphur compounds can mediate a shift between fly and wasp pollination systems
    Adam Shuttleworth
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Proc Biol Sci 277:2811-9. 2010
    ..This suggests that mutations affecting the production of particular scent compounds could precipitate shifts between pollinators, independently of floral morphology, colour or nectar properties...
  9. pmc Relationships between population size and pollen fates in a moth-pollinated orchid
    Steven D Johnson
    School of Biological and Conservation Sciences, University of Kwa, Zulu NatalScottsville, Pietermaritzburg 3209, South Africa
    Biol Lett 5:282-5. 2009
    ....
  10. pmc Carrion mimicry in a South African orchid: flowers attract a narrow subset of the fly assemblage on animal carcasses
    Timotheüs van der Niet
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Scottsville, Pietermaritzburg, South Africa
    Ann Bot 107:981-92. 2011
    ..Pollination success and the incidence of pollinator-mediated self-pollination were measured and these were compared with values for orchids with sexual- and food-deceptive pollination systems...
  11. ncbi Mimics and magnets: the importance of color and ecological facilitation in floral deception
    Craig I Peter
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville 3209, South Africa
    Ecology 89:1583-95. 2008
    ..Flower color and location of E. zeyheriana plants relative to rewarding magnet patches are therefore key components of the exploitation by this orchid of the relationship between W. cuspidata and Lipotriches bee pollinators...
  12. ncbi Effects of volatile compounds emitted by Protea species (Proteaceae) on antennal electrophysiological responses and attraction of cetoniine beetles
    Sandy Lynn Steenhuisen
    School of Life Sciences, University of KwaZulu Natal, Post Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa
    J Chem Ecol 39:438-46. 2013
    ....
  13. doi Chemical mimicry of insect oviposition sites: a global analysis of convergence in angiosperms
    Andreas Jürgens
    School of Life Sciences, University of KwaZulu Natal, P Bag X01 Scottsville, Pietermaritzburg, 3209, South Africa
    Ecol Lett 16:1157-67. 2013
    ....
  14. doi The relative contributions of insect and bird pollinators to outcrossing in an African Protea (Proteaceae)
    Sandy Lynn Steenhuisen
    School of Life Sciences, University of KwaZulu Natal, P Bag X01, Scottsville, 3209, Pietermaritzburg, South Africa
    Am J Bot 99:1104-11. 2012
    ..We used selective exclusion experiments to assess the importance of insects for outcrossing in Protea caffra, a facultatively autogamous shrub with scented flowers that are visited frequently by both birds and insects (mainly beetles)...
  15. doi Effects of self-compatibility on the distribution range of invasive European plants in North America
    Mark van Kleunen
    Centre for Invasion Biology, School of Biological and Conservation Sciences, University of KwaZulu Natal, P Bag X01 Scottsville, Pietermaritzburg 3209, South Africa
    Conserv Biol 21:1537-44. 2007
    ..These results support Baker's law, and we recommend that screening protocols for predicting invasiveness of species considered for introduction should include assessment of their breeding system...
  16. doi Phylogenetically independent associations between autonomous self-fertilization and plant invasiveness
    Mark van Kleunen
    Centre for Invasion Biology, School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01 Scottsville, Pietermaritzburg 3209, South Africa
    Am Nat 171:195-201. 2008
    ..This was especially true for the naturalized species that are considered to be invasive weeds. These results provide strong evidence for the role of autonomous seed production in increasing potential invasiveness in plants...
  17. ncbi Lack of floral nectar reduces self-pollination in a fly-pollinated orchid
    Jana Jersáková
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Pietermaritzburg, ZA 3209, South Africa
    Oecologia 147:60-8. 2006
    ..These findings provide support for the idea that floral deception serves to reduce pollinator-mediated self-pollination...
  18. ncbi Transition from wind pollination to insect pollination in sedges: experimental evidence and functional traits
    Peter D Wragg
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Scottsville, South Africa
    New Phytol 191:1128-40. 2011
    ..These results show that a transition from wind pollination to insect pollination occurred in sedges and shed new light on the function of traits involved in this important transition...
  19. pmc Floral signposts: testing the significance of visual 'nectar guides' for pollinator behaviour and plant fitness
    Dennis M Hansen
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Proc Biol Sci 279:634-9. 2012
    ..Our results confirm that the markings on L. oreogena flowers serve as nectar guides and suggest that they are under strong selective maintenance through both male and female fitness components in this pollination system...
  20. pmc The pollination niche and its role in the diversification and maintenance of the southern African flora
    Steven D Johnson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Philos Trans R Soc Lond B Biol Sci 365:499-516. 2010
    ..I thus also consider the evidence that disturbance provokes pollination failure in some southern African plants with specialized pollination systems...
  21. pmc Doing the twist: A test of Darwin's cross-pollination hypothesis for pollinarium reconfiguration
    Craig I Peter
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville 3209, South Africa
    Biol Lett 2:65-8. 2006
    ..Reconfiguration times were also consistently longer than pollinator visit times. These results provide strong support for Darwin's idea that this mechanism promotes cross-pollination...
  22. pmc Mammal pollinators lured by the scent of a parasitic plant
    Steven D Johnson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Proc Biol Sci 278:2303-10. 2011
    ..3-hexanone is also known from some bat-pollinated species, suggesting independent evolution of plant signals in derived, highly specialized mammal-pollination systems...
  23. doi Patterns of plant speciation in the Cape floristic region
    Timotheüs van der Niet
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa
    Mol Phylogenet Evol 51:85-93. 2009
    ..We conclude that ecological speciation is likely to have been important for radiation of the Cape flora, but there is no evidence as yet for special "Cape" patterns of ecological speciation...
  24. ncbi The geographical mosaic of coevolution in a plant-pollinator mutualism
    Bruce Anderson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, P Bag X01, Scottsville, Pietermaritzburg, South Africa
    Evolution 62:220-5. 2008
    ..We conclude that coevolution is a compelling explanation for the geographical covariation in flower depth and fly proboscis length...
  25. pmc Anther cap retention prevents self-pollination by elaterid beetles in the South African orchid Eulophia foliosa
    Craig I Peter
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, 3209, South Africa
    Ann Bot 97:345-55. 2006
    ..Here an unusual mechanism--anther cap retention--that appears to prevent self-pollination in the South African orchid Eulophia foliosa is examined...
  26. pmc The effects of floral mimics and models on each others' fitness
    Bruce Anderson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Post Bag X01 Scottsville, Pietermaritzburg 3209, South Africa
    Proc Biol Sci 273:969-74. 2006
    ..We propose that changes in pollinator flight behaviour, rather than pollinator conditioning, are likely to account for negative frequency-dependent reproductive success in deceptive orchids...
  27. ncbi Dark, bitter-tasting nectar functions as a filter of flower visitors in a bird-pollinated plant
    Steven D Johnson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, P Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Ecology 87:2709-16. 2006
    ..Thus the dark phenolic component of the nectar appears to function as a floral filter by attracting some animals visually and deterring others by its taste...
  28. doi Three-dimensional geometric morphometrics for studying floral shape variation
    Timotheüs van der Niet
    School of Biological and Conservation Sciences, University of KwaZulu Natal, P Bag X01, Pietermaritzburg 3209, South Africa
    Trends Plant Sci 15:423-6. 2010
    ....
  29. pmc A temporal dimension to the influence of pollen rewards on bee behaviour and fecundity in Aloe tenuior
    Karl J Duffy
    School of Life Sciences, University of KwaZulu Natal, Scottsville, Pietermaritzburg, South Africa
    PLoS ONE 9:e94908. 2014
    ..Therefore the benefit of providing pollen that is accessible to bee foragers outweighs any potential costs to fitness in terms of gender interference in this species...
  30. pmc Ancestral deceit and labile evolution of nectar production in the African orchid genus Disa
    Steven D Johnson
    School of Life Sciences, University of KwaZulu Natal, Scottsville, Pietermaritzburg 3209, South Africa
    Biol Lett 9:20130500. 2013
    ....
  31. pmc Pollination function transferred: modified tepals of Albuca (Hyacinthaceae) serve as secondary stigmas
    Steven D Johnson
    School of Life Sciences, University of KwaZulu Natal, P Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Ann Bot 110:565-72. 2012
    ..Here it is shown that a functional stigma has evolved secondarily from modified tepals in some Albuca species (Hyacinthaceae)...
  32. ncbi Palp-faction: an African milkweed dismembers its wasp pollinators
    Adam Shuttleworth
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Postal Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Environ Entomol 38:741-7. 2009
    ..The plants, however, gain clear benefit from the interaction, as verified by the removal and insertion of pollinia in flowers exposed solely to visits by pompilid wasps...
  33. ncbi Heteromorphic incompatibility and efficiency of pollination in two distylous Pentanisia species (Rubiaceae)
    Paulo H Massinga
    School of Botany and Zoology, University of KwaZulu Natal, Private Bag X01, Scottsville, Pietermaritzburg, 3209, South Africa
    Ann Bot 95:389-99. 2005
    ..Distyly and its pollination consequences were examined in two Pentanisia species with long-tubed flowers which are pollinated almost exclusively by butterflies...
  34. pmc Is Eucalyptus Cryptically Self-incompatible?
    Tasmien N Horsley
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Scottsville, South Africa
    Ann Bot 100:1373-8. 2007
    ..The probability that seeds will be fertilized from self- versus cross-pollen depends strongly on whether plants have self-incompatibility systems, and how these systems influence the fate of pollen tubes...
  35. doi Floral mimicry enhances pollen export: the evolution of pollination by sexual deceit outside of the orchidaceae
    Allan G Ellis
    School of Biological and Conservation Sciences, University of KwaZulu Natal, Scottsville, Pietermaritzburg 3209, South Africa
    Am Nat 176:E143-51. 2010
    ....
  36. pmc A pollinator shift explains floral divergence in an orchid species complex in South Africa
    Craig I Peter
    School of Life Sciences, University of KwaZulu Natal, Private Bag X01, Scottsville, 3209, South Africa
    Ann Bot 113:277-88. 2014
    ..In this study, two forms were identified within this complex that differ in distribution, floral morphology, scent chemistry and phenology, and a test was made of whether these differences represent adaptations for different pollinators...
  37. pmc Flower colour adaptation in a mimetic orchid
    Ethan Newman
    Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
    Proc Biol Sci 279:2309-13. 2012
    ..This phenotype by environment interaction demonstrates that the flower colour shift in D. ferruginea is adaptive and driven by local colour preference in its pollinator...
  38. ncbi Pollinators, "mustard oil" volatiles, and fruit production in flowers of the dioecious tree Drypetes natalensis (Putranjivaceae)
    Steven D Johnson
    School of Biological and Conservation Sciences, University of KwaZulu Natal, P Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Am J Bot 96:2080-6. 2009
    ..The apparent constitutive emission of isothiocyanates raises interesting new questions about their functional role in flowers...
  39. ncbi The evolution of floral variation without pollinator shifts in Gorteria diffusa (Asteraceae)
    Allan G Ellis
    School of Biological and Conservation Sciences, University of KwaZulu Natal, P Bag X01, Scottsville, Pietermaritzburg 3209, South Africa
    Am J Bot 96:793-801. 2009
    ..Much of the extensive variation in floral form in G. diffusa therefore appears to have arisen without evolutionary shifts between pollinator types...
  40. ncbi Macroevolutionary data suggest a role for reinforcement in pollination system shifts
    Timotheüs van der Niet
    Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, 8008, Zurich, Switzerland
    Evolution 60:1596-601. 2006
    ..In contrast, there is no significant association between pollination system shifts and edaphic shifts for allopatric sister species. These results are interpreted as evidence for reinforcement...
  41. ncbi The pollination ecology of an assemblage of grassland asclepiads in South Africa
    Jeff Ollerton
    Landscape and Biodiversity Research Group, School of Environmental Science, University College Northampton, Park Campus, Northampton NN2 7AL, UK
    Ann Bot 92:807-34. 2003
    ..The research has shown that there is still much to be learned about plant-pollinator interactions in areas of high plant diversity such as South Africa...
  42. pmc Pollinator-mediated selection on flower-tube length in a hawkmoth-pollinated Gladiolus (Iridaceae)
    Ronny Alexandersson
    Department of Plant Ecology, Evolutionary Biology Centre, Uppsala University, Villavägen 14, SE 752 36, Uppsala, Sweden
    Proc Biol Sci 269:631-6. 2002
    ..This study demonstrates that selection may occur among plants with natural phenotypic variation in flower-tube length, and supports Darwin's model of pollinator-mediated selection...
  43. ncbi Coloured nectar: distribution, ecology, and evolution of an enigmatic floral trait
    Dennis M Hansen
    Institute of Environmental Sciences, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
    Biol Rev Camb Philos Soc 82:83-111. 2007
    ..Neither of these possibilities are mutually exclusive. Recent studies have provided experimental evidence for the first two hypotheses, and we suggest promising avenues for future research into this little-known floral trait...
  44. ncbi Do floral syndromes predict specialization in plant pollination systems? An experimental test in an "ornithophilous" African Protea
    Anna L Hargreaves
    Biology Department, Trent University, 1600 West Bank Drive, Peterborough, Ontario, K9 J 7B8, Canada
    Oecologia 140:295-301. 2004
    ..Our results show that P. roupelliae is largely dependent on birds for pollination, and thus confirm the utility of floral syndromes for generating hypotheses about the ecology of pollination systems...