The diversity, ecology and evolution of extrafloral nectaries: Current perspectives and future challenges

Annals of Botany

Volumn 111, Issue 6, 2013, Pages 1243-1250

  Marazzi, Brigitte ^a,c   Bronstein, Judith L ^a   Koptur, Suzanne ^b  

^a University of Arizona   (United States)

^b FLORIDA INTERNATIONAL UNIVERSITY   (United States)

^c INSTITUTO DE BOTÁNICA DEL NORDESTE   (Argentina)

Author keywords

Angiosperms; ant plant interactions; ants; extrafloarl nectaries; extranuptial; extrasoral; ferns; herbivory; interaction networks; mutualisms; nectar; plant defence; protection

Indexed keywords

ANT; ARTHROPOD; FERN; FUTURE PROSPECT; GENOMICS; HABITAT TYPE; MORPHOLOGY; MUTUALISM; NECTAR; NECTARY; PHYLOGENETICS; PHYLOGENY; PLANT COMMUNITY; PLANT DEFENSE; PLANT-INSECT INTERACTION; SECRETION;

ANGIOSPERM; ANIMAL; ANT; ANT-PLANT INTERACTIONS; EVOLUTION; EXTRAFLOARL NECTARIES; EXTRANUPTIAL; EXTRASORAL; FERN; HERBIVORY; HISTOLOGY; INTERACTION NETWORKS; MUTUALISMS; NECTAR; PLANT; PLANT DEFENCE; PROTECTION; REVIEW; SECRETION (PROCESS); SYMBIOSIS;

ANGIOSPERMS; ANT-PLANT INTERACTIONS; ANTS; EXTRAFLOARL NECTARIES; EXTRANUPTIAL; EXTRASORAL; FERNS; HERBIVORY; INTERACTION NETWORKS; MUTUALISMS; NECTAR; PLANT DEFENCE; PROTECTION;

ANIMALS; ANTS; BIOLOGICAL EVOLUTION; PLANT NECTAR; PLANTS; SYMBIOSIS;

ANIMALIA; ARTHROPODA; FILICOPHYTA; FORMICIDAE; MAGNOLIOPHYTA;

EID: 84878307081     PISSN: 03057364     EISSN: 10958290     Source Type: Journal    
DOI: 10.1093/aob/mct109     Document Type: Review

References (127)

1. Angiosperm Phylogeny Group. 1998. An ordinal classification for the families of flowering plants. Annals of the Missouri Botanical Garden 85: 531-553.
2. Angiosperm PhylogenyGroup. 2009. An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APGIII. Botanical Journal of the Linnean Society 161: 105-121.
3. Bartholmes C, Hidalgo O, Gleissberg S. 2012. Evolution of the YABBY gene family with emphasis on the basal eudicot Eschscholzia californica (Papaveraceae). Plant Biology 14: 11-23.
4. Bascompte J, Jordano P. 2007. Plant-animal mutualistic networks: the architecture of biodiversity. Annual Review of Ecology, Evolution and Systematics 38: 567-593.
5. Bascompte J, JordanoP, Melian CJ, Olesen JM. 2003. The nested assembly of plant-animal mutualistic networks. Proceedings of the National Academy of Sciences USA 100: 9383-9387.
6. Beattie AJ. 1985. The evolutionary ecology of ant-plant mutualisms. Cambridge: Cambridge University Press.
7. Becerra JX, Venable DL. 1991. The role of ant-Homoptera mutualisms in the evolution of extrafloral nectaries. Oikos 60: 105-106.
8. Bentley BL. 1977. Extrafloral nectaries and protection by pugnacious bodyguards. Annual Review of Ecology and Systematics 8: 407-427.
9. Bininda-Emonds OR. 2004. The evolution of supertrees. Trends in Ecology & Evolution 19: 315-322.
10. Bixenmann RJ, Coley PD, Kursar TA. 2011. Is extrafloral nectar production induced by herbivores or ants in a tropical facultative ant-plant mutualism? Oecologia 165: 417-425.
11. Bluthgen N, Fiedler K. 2004a. Preferences for sugars and amino acids and their conditionality in a diverse nectar-feeding ant community. Journal of Animal Ecology 73: 155-166.
12. Bluthgen N, Fiedler K. 2004b. Competition for composition: lessons from nectar-feeding ant communities. Ecology 85: 1479-1485.
13. Bluthgen N, Reifenrath K. 2003. Extrafloral nectaries in an Australian rainforest: structure and distribution. Australian Journal of Botany 51: 515-527.
14. Bluthgen N, Verhaagh M, Goitia W, Jaffe K, Morawetz W, Barthlott W. 2000. How plants shape the ant community in the Amazonian rainforest canopy: the key role of extrafloral nectaries and homopteran honeydew. Oecologia 125: 229-240.
15. Bluthgen N, Gottsberger G, Fiedler K. 2004. Sugar and amino acid composition of ant-attended nectar and honeydew sources from an Australian rainforest. Austral Ecology 29: 418-429.
16. Bowman JL, Smyth DR. 1999. CRABS CLAW, a gene that regulates carpel and nectary development in Arabidopsis, encodes a novel protein with zinc finger and helix-loop-helix domains. Development 126: 2387-2396.
17. Bronstein JL. 1998. The contribution of ant-plant protection studies to our understanding of mutualism. Biotropica 30: 150-161.
18. Butler MA, King AA. 2004. Phylogenetic comparative analysis: a modeling approach for adaptive evolution. American Nataturalist 164: 683-695.
19. Byk J, Del-Claro K. 2011. Ant-plant interaction in the Neotropical savanna: direct beneficial effects of extrafloral nectar on ant colony fitness. Population Ecology 53: 327-332.
20. Caspary R. 1848. De nectariis. Adolphum Marcum. Botanische Zeitung 6: 628-630.
21. Chamberlain SA, Holland JN. 2009. Quantitative synthesis of context dependency in ant-plant protection mutualisms. Ecology 90: 2384-2392.
22. CuautleM,Rico-GrayV. 2003. The effect ofwasps and ants on the reproductive success of the extrafloral nectaried plant Turnera ulmifolia (Turneraceae). Functional Ecology 17: 417-423.
23. Darwin C. 1876. The effects of cross and self-fertilisation in the vegetable kingdom. London: John Murray.
24. Darwin F. 1877. On the nectar glands of the common brakefern. Botanical Journal of the Linnean Society 15: 407-409.
25. Davidson DW. 1997. The role of resource imbalances in the evolutionary ecology of tropical arboreal ants. Biological Journal of the Linnean Society 61: 153-181.
26. Delpino F. 1868-1875. Ulteriori osservazioni sulla dicogamia nel regno vegetale. I & II. Atti della Societa Italiana di Scienze Naturali, XI, XII.
27. Diaz-Castelazo C, Rico-Gray V, Ortega F, Angeles G. 2005. Morphological and secretory characterization of extrafloral nectaries in plants of coastal Veracruz, Mexico. Annals of Botany 96: 1175-1189.
28. Diaz-Castelazo C, Sanchez-Galvan IR, Guimaraes PR Jr, Raimundo RLG, Rico-Gray V. 2013. Long-term temporal variation in the organization of an ant-plant network. Annals of Botany 111: 1285-1293.
29. EichhornMP,Ratliffe LC,PollardKM.2011. Attraction of ants by an invasive Acacia. Insect Conservation and Diversity 4: 235-238.
30. Emerson BC. 2002. Evolution on oceanic islands: molecular phylogenetic approaches to understanding pattern and process. Molecular Ecology 11: 951-966.
31. Escalante-PerezM, Heil M. 2012. Nectar secretion: its ecological context and physiological regulation. Secretions and Exudates in Biological Systems 12: 187-219.
32. Escalante-PerezM, JaborskyM, Lautner S, et al. 2012. Poplar extrafloral nectaries: two types, two strategies of indirect defenses against herbivores. Plant Physiology 159: 1176-1191.
33. Fahn A. 1979. Secretory tissues in plants. London: Academic Press.
34. de la Fuente MAS, Marquis RJ. 1999. The role of ant-tended extrafloral nectaries in the protection and benefit of a neotropical rainforest tree. Oecologia 118: 192-202.
35. Green PT, O'Dowd DJ, Abbott KL, Jeffery M,RetallickK, Nally RM. 2011. Invasional meltdown: invader-invader mutualism facilitates a secondary invasion. Ecology 92: 1758-1768.
36. Hansen DM, Olesen JM, Mione T, Johnson SD, Mu ller CB. 2007. Coloured nectar: distribution, ecology, and evolution of an enigmatic floral trait. Biological Reviews 82: 83-111.
37. Heads PA, Lawton JH. 1985. Bracken, ants and extrafloral nectaries. III. How insect herbivores avoid ant predation. Ecological Entomology 10: 29-42.
38. Heil M. 2011. Nectar: generation, regulation and ecological functions. Trends in Plant Science 16: 191-200.
39. Heil M, McKey D. 2003. Protective ant-plant interactions as a model system in ecological and evolutionary research. Annual Review in Ecology, Evolution and Systematics 34: 425-453.
40. Heil M, Baumann B, Kruger R, Linsenmair K. 2004. Main nutrient compounds in food bodies of Mexican Acacia ant-plants. Chemoecology 14: 45-52.
41. Heil M, Rattke J, BolandW. 2005. Post-secretory hydrolysis of nectar sucrose and specialization in ant/plant mutualism. Science 308: 560-563.
42. Heil M, Gonzalez-Teuber M, Clement LW, Kautz S, Verhaagh M, Bueno JCS. 2009. Divergent investment strategies of Acacia myrmecophytes and the coexistence of mutualists and exploiters. Proceedings of the National Academy of Sciences USA 106: 18091-18096.
43. Heil M, Orona-Tamayo D, Eilmus S, Kautz S, Gonzalez-Teuber M. 2010. Chemical communication and coevolution in an ant-plant mutualism. Chemoecology 20: 63-74.
44. Huelsenbeck JP, Rannala B. 1997. Phylogenetic methods come of age: testing hypotheses in an evolutionary context. Science 276: 227-232.
45. HuelsenbeckJP,RonquistF, Nielsen R, Bollback JP. 2001.Bayesian inference of phylogeny and its impact on evolutionary biology. Science 294: 2310-2314.
46. Keeler KH. 1979. Distribution of plants with extrafloral nectaries and ants at two elevations in Jamaica. Biotropica 11: 152-154.
47. Keeler KH. 1985. Extrafloral nectaries on plants in communities without ants: Hawaii. Oikos 44: 407-414.
48. Kelly CA. 1986. Extrafloral nectaries: ants, herbivores and fecundity in Cassia fasciculata. Oecologia 69: 600-605.
49. Koptur S. 1979. Facultative mutualism between weedy vetches bearing extrafloral nectaries and weedy ants in California. American Journal of Botany 66: 1016-1020.
50. Koptur S. 1989. Is extrafloral nectar production an inducible defense? In: Bock J, Linhart J. eds. Evolutionary ecology of plants. Boulder, CO: Westview Press, 323-339.
51. Koptur S. 1992. Extrafloral nectary-mediated interactions between insects and plants. In: Bernays E. ed. Insect-plant interactions, volume IV. London: CRC Press, 81-129.
52. Koptur S. 2005. Nectar as fuel for plant protectors. In:Wackers F, van Rijn PCJ, Bruin J. eds. Plant-provided food for carnivorous insects. Cambridge: Cambridge University Press, 75-108.
53. Koptur S, Palacios-Rios M, Diaz-Castelazo C, Mackay WP, Rico-Gray V. 2013. Nectar secretion on fern fronds associated with lower levels of herbivore damage: field experiments with a widespread epiphyte of Mexican cloud forest remnants. Annals of Botany 111: 1277-1283.
54. Krosnick S, Gasser C,Potter D. 2011.Passiflora as a model system for studying nectary diversification: insights and implications. Abstract book of the XVI International Botanical Conference (IBC2011, Melbourne, Australia): 63-64. Available at http://www.ibc2011.com/downloads/IBC2011-Abstract-Book.pdf.
55. KwokKE, Laird RA. 2012. Plant age and the inducibility of extrafloral nectaries in Vicia faba. Plant Ecology 213: 1823-1832.
56. Lach L, Hobbs ER, Majer EJD. 2009. Herbivory-induced extrafloral nectar increases native and invasive ant worker survival. Population Ecology 51: 237-243.
57. Lach L, TillbergCV, SuarezAV. 2010.Contrasting effects of an invasive ant on a native and an invasive plant. Biological Invasions 12: 3123-3133.
58. Lanan MC, Bronstein JL. 2013. An ant's-eye view of an ant-plant protection mutualism. Oecologia, in press. doi:10.1007/s00442-012-2528-0.
59. Lee JY, Baum SF, Alvarez J, Patel A, Chitwood DH, Bowman JL. 2005a. Activation of CRABS CLAW in the nectaries and carpels of Arabidopsis. Plant Cell 17: 25-36.
60. Lee JY, Baum SF, Oh SH, Jiang CZ, Chen CJ, Bowman JL. 2005b. Recruitment of CRABS CLAW to promote nectary development within the eudicot clade. Development 132: 5021-5032.
61. Lengyel S, Gove AD, Latimer AM, Majer JD, Dunn RR. 2009. Ants sow the seeds of global diversification in flowering plants. PLoS ONE 4: pe5480.
62. Lengyel S, Gove AD, Latimer AM, Majer JD, Dunn RR. 2010. Convergent evolution of seed dispersal by ants, and phylogeny and biogeography in flowering plants: a global survey. Perspectives in Plant Ecology, Evolution and Systematics 12: 43-55.
63. Letourneau DK. 1983. Passive aggression: an alternative hypothesis for the Piper-Pheidole association. Oecologia 60: 122-126.
64. Lundgren JG. 2009. Nutritional aspects of non-prey foods in the life histories of predaceous Coccinellidae. Biological Control 51: 294-305.
65. Machado SR, Morellato LPC, Sajo MG, Oliveira PS. 2008. Morphological patterns of extrafloral nectaries in woody plant species of the Brazilian cerrado. Plant Biology 10: 660-673.
66. Marazzi B, Sanderson MJ. 2010. Large-scale patterns of diversification in the widespread legume genus Senna and the evolutionary role of extrafloral nectaries. Evolution 64: 3570-3592.
67. Marazzi B, McMahonMM,Lanan M, Bronstein JL. 2011. Diversity and evolution of extrafloral nectaries in Sonoran desert plants. Abstract book of the XVI International Botanical Conference (IBC2011, Melbourne, Australia): 616 (e-poster P0882). Available at http://www.ibc2011.com/downloads/IBC2011- Abstract-Book.pdf.
68. Marazzi B,Ane C, SimonM,Delagado Salinas A,LuckowM,SandersonMJ. 2012. Locating evolutionary precursors on a phylogenetic tree. Evolution 66: 3918-3930.
69. Marazzi B, Conti E, Sanderson MJ, McMahon MM, Bronstein JL. 2013. Diversity and evolution of a trait mediating ant-plant interactions: insights from extrafloral nectaries in Senna (Leguminosae). Annals of Botany 111: 1263-1275.
70. Mathews CR, Bottrell DG, BrownMW. 2009. Extrafloral nectaries alter arthropod communitystructure and mediate peach (Prunus persica) plant defense. Ecological Applications 19: 722-730.
71. MathewsS. 2009. Phylogenetic relationshipsamongseed plants: persistent questions and the limits of molecular data. American Journal of Botany 96: 228-236.
72. McKey D. 1984. Interaction of the ant-plant Leonardoxa africana (Caesalpiniaceae) with its obligate inhabitants in a rainforest in Cameroon. Biotropica 16: 81-99.
73. McKey D. 1989. Interactions between ants and leguminous plants. In: Stirton CH, Zarucchi JL. eds. Advances in legume biology. Monographs in Systematic Botany from the Missouri Botanical Garden 29: 673-718.
74. Melo Y, Machado SR, Alves M. 2010. Anatomy of extrafloral nectaries in Fabaceae from dry-seasonal forest in Brazil. Botanical Journal of the Linnean Society 163: 87-98.
75. Miller TEX. 2007. Does having multiple partners weaken the benefits of facultative mutualism? A test with cacti and cactus-tending ants. Oikos 116: 500-512.
76. Mizell RF. 2001. Many plants have extrafloral nectaries helpful to beneficials. University of Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, EDIS. http://edis.ifas.ufl.edu/in175.
77. MondorEB,TremblayMN,MessingRH.2006. Extrafloral nectary phenotypic plasticity is damage-and resource-dependent in Vicia faba. Biology Letters 2: 583-585.
78. MorrisWF,WilsonWG,Bronstein JL, Ness JH. 2005. Environmental forcing and the competitive dynamics of a guild of cactus-tending ant mutualists. Ecology 86: 3190-3199.
79. Ness JH. 2003. Catalpa bignonioides alters extrafloral nectar production after herbivory and attracts ant bodyguards. Oecologia 134: 210-218.
80. Ness JH, Morris WF, Bronstein JL. 2006. Integrating quality and quantity of mutualistic service to contrast ant species visiting Ferocactus wislizeni, a plant with extrafloral nectaries. Ecology 87: 912-921.
81. Ness JH, Morris WF, Bronstein JL. 2009. For ant-protected plants, the best defense is a hungry offense. Ecology 90: 2823-2831.
82. Nicolson SW. 2007. Nectar consumers. In Nicolson SW, Nepi M, Pacini E. eds. Nectaries and Nectar. Dordrecht: Springer, 289-342.
83. Nicolson SW, ThornburgRW. 2007. Nectar chemistry. In: Nicolson SW, Nepi M, Pacini E. eds. Nectaries and nectar. Dordrecht: Springer, 215-264.
84. Nicolson SW, Nepi M, Pacini E. 2007. Nectaries and nectar. Dordrecht: Springer.
85. NogueiraA, Guimaraes E,Machado SR, Lohmann LG. 2012a.Do extrafloral nectaries present a defensive role against herbivores in two species of the family Bignoniaceae in a Neotropical savanna? Plant Ecology 213: 289-301.
86. Nogueira A, Rey PJ, Lohmann LG. 2012b. Evolution of extrafloral nectaries: adaptive process and selective regime changes from forest to savanna. Journal of Evolutionary Biology 25: 2325-2340.
87. O'Dowd DJ, Catchpole EA. 1983. Ants and extrafloral nectaries: no evidence for plant protection in Helichrysum spp.-ant interactions. Oecologia 59: 191-200.
88. Orona-Tamayo D, Wielsch N, Escalante-Perez M, et al. 2013. Short-term proteomic dynamics reveal metabolic factory for active extrafloral nectar secretion by Acacia cornigera ant-plants. The Plant Journal 73: 546-554.
89. Pacini E, Nepi M. 2007. Nectar production and presentation. In Nicolson SW, NepiM, Pacini E. eds. Nectaries and nectar. Dordrecht: Springer, 167-Nicolson SW, NepiM, Pacini E. eds. Nectaries and nectar. Dordrecht: Springer, 167
90. Palmer TM, Doak DF, Stanton ML, et al. 2010. Synergy of multiple partners, including freeloaders, increases host fitness in a multispecies mutualism. Proceedings of the National Academy of Sciences USA 107: 17234-17239.
91. PembertonRW. 1993. Observations of extrafloral nectar feeding by predaceous and fungivorous mites. Proceedings of the Entomological Society of Washington 95: 642-643.
92. PembertonRW, Vandenberg NJ. 1993. Extrafloral nectar feeding by ladybird beetles (Coleoptera: Coccinellidae). Proceedings of the Entomological Society of Washington 95: 139-151.
93. Pulice CE, Packer AA. 2008. Simulated herbivory induces extrafloral nectary production in Prunus avium. Functional Ecology 22: 801-807.
94. deQueiroz A, Gatesy J. 2007. The supermatrix approach to systematics. Trends in Ecology & Evolution 22: 34-41.
95. Radhika V, Kost C, Mithofer A, Boland W. 2010. Regulation of extrafloral nectar secretion by jasmonates in lima bean is light dependent. Proceedings of the National Academy of Sciences 107: 17228-17233.
96. Rashbrook VK, Compton SG, Lawton JH. 1993. Ant-herbivore interactions: reasons for the absence of benefit to a fern with foliar nectaries. Ecology 73: 2167-2174.
97. Rickson FR, Rickson MM. 1998. The cashew nut, Anacardium occidentale (Anacardiaceae), and its perennial association with ans: extrafloral nectary location and the potential for ant defense9. American Journal of Botany 85: 835-849.
98. Rico-Gray V, Oliveira PS. 2007. The ecology and evolution of ant-plant interactions. Chicago: University Chicago Press.
99. Rogers WE, Siemann E, Lankau RA. 2003. Damage induced production of extrafloral nectaries in native and invasive seedlings of chinese tallow tree (Sapium sebiferum). The American Midland Naturalist 149: 413-417.
100. Rosenzweig ML. 2002. The distraction hypothesis depends on relatively cheap extrafloral nectaries. Evolutionary Ecology Research 4: 307-311.
101. Ruhren S, Handel SN. 1999. Jumping spiders (Salticidae) enhance the seed production of a plant with extrafloral nectaries. Oecologia 119: 227-230.
102. Sanderson MJ, Hufford L. 1996. Homoplasy: the recurrence of similarity in evolution. New York: Academic Press.
103. Savage AM, Rudgers JA. 2013. Non-additive benefit or cost? Disentangling the indirect effects that occur when plants bearing extrafloral nectaries and honeydew-producing insects share exotic ant mutualists. Annals of Botany 111: 1295-1307.
104. SavageAM,Rudgers JA, Whitney KD. 2009. Elevated dominance of extrafloral nectary-bearing plants is associated with increased abundances of an invasive ant and reduced native ant richness. Diversity and Distributions 15: 751-761.
105. Schmid R. 1988. Reproductive versus extra-reproductive nectaries-historical perspective and terminological recommendations. Botanical Review 54: 179-232.
106. Schmid VS, Schmid S, Steiner J, Zillikens A. 2010. High diversity of ants foraging on extrafloral nectar of bromeliads in the Atlantic rainforest of southern Brazil. Studies on Neotropical Fauna and Environment 45: 39-53.
107. Simberloff D, Von Holle B. 1999. Positive interactions of nonindigenous species: invasional meltdown? Biological Invasions 1: 21-32.
108. SmithLL,LanzaJ, SmithGC.1990.Aminoacid concentrations in the extrafloral nectar of Impatiens sultani increase after simulated herbivory. Ecology 71: 107-115.
109. Smith S, Beaulieu J, Donoghue M. 2009. Mega-phylogeny approach for comparative biology: an alternative to supertree and supermatrix approaches. BMC Evolutionary Biology 9: 37.
110. Stott P, Pemberton RW. 1998. The occurrence and abundance of plants with extrafloral nectaries, the basis for antiherbivore defensive mutualisms, along a latitudinal gradient in East Asia. Journal of Biogeography 25: 661-668.
111. ThomasV. 1991. Structural, functional and phylogenetic aspects of the colleter. Annals of Botany 68: 287-305.
112. Tillberg CV, Breed MD. 2004. Placing an omnivore in a complex food web: dietary contributions to adult biomass of an ant. Biotropica 36: 266-271.
113. Trager MD, Bhotika S, Hostetler JA, et al. 2010. Benefits for plants in ant-plant protective mutualisms: a meta-analysis. PLoS ONE 5: pe14308.
114. Vogel S. 1997. Remarkable nectaries: structure, ecology, organophyletic perspectives. I. Substitutive nectaries. Flora 192: 305-333.
115. Vogel S. 1998a. Remarkable nectaries: structure, ecology, organophyletic perspectives. II. Nectarioles. Flora 193: 1-29.
116. Vogel S. 1998b. Remarkable nectaries: structure, ecology, organophyletic perspectives. IV. Miscellaneous cases. Flora 193: 225-248.
117. Wackers FL. 2001.Acomparison of nectar-and honeydewsugars with respect to their utilization by the hymenopteran parasitoidCotesia glomerata. Journal of Insect Physiology 47: 1077-1084.
118. Wackers FL, BonifayC. 2004. Howto be sweet? Extrafloral nectar allocation by Gossypium hirsutum fits optimal defense theory predictions. Ecology 85: 1512-1518.
119. Wackers FL, van Rijn PC. 2005. Food for protection: an introduction. In:Wackers FL, van Rijn PCJ, Bruin J. eds. Plant-provided food for carnivorous insects: a protective mutualism and its applications. New York: Cambridge University Press, 1-14.
120. Wagner D, Fleur Nicklen E. 2010. Ant nest location, soil nutrients and nutrient uptake by ant-associated plants: does extrafloral nectar attract ant nests and thereby enhance plant nutrition? Journal of Ecology 98: 614-624.
121. Wagner D, Kay A. 2002. Do extrafloral nectaries distract ants from visiting flowers? An experimental test of an overlooked hypothesis. Evolutionary Ecological Research 4: 293-305.
122. Wake DB,Wake MH, Specht CD. 2011. Homoplasy: from detecting pattern to determining process and mechanismof evolution. Science 331: 1032-1035.
123. Weber MG, Agrawal AA. 2012. Phylogeny, ecology, and the coupling of comparative and experimental approaches. Trends in Ecology & Evolution 27: 394-403.
124. Weber MG, Keeler KH. 2013. The phylogenetic distribution of extrafloral nectaries in plants. Annals of Botany 111: 1251-1261.
125. Weber MG, Clement WL, Donoghue MJ, Agrawal AA. 2012. Phylogenetic and experimental tests of interactions among mutualistic plant defense traits in Viburnum (Adoxaceae). The American Naturalist 180: 450-463.
126. Whitney KD. 2004. Experimental evidence that both parties benefit in a facultative plant-spider mutualism. Ecology 85: 1642-1650.
127. Zimmerman JG 1932 U ber die extrafloralen Nektarien der Angiospermen. Beihefte Zum Botanischen Zentralblatt 49: 99-196.