Nonflying Mammal Pollination of Southern African Proteas: A Non-Coevolved System

摘要: Traits characterizing those proteas adapted for pollination by nonflying mammals include: bowlshaped heads bearing fleshy bracts, these borne on short, flexible peduncles, often at or near ground level (geoflorous) and hidden beneath dense overlying foliage (cryptic), producing copious nectar (ca. 1.8 ml/head, standing crop); individual florets with wiry, yet styles a nectar-stigma distance of 10 mm; distinctive yeastlike odor; nocturnal anthesis; sucrose-rich high total carbohydrate content 36%) relatively low proportion amino acids. Evidence small-mammal visitation to protea flowering includes: the presence pollen rostra (carried in position effect when foraging nectar); transport fluorescing powders both within between plants; accumulation feces heads, destruction exclosure bags containing nectar-rich heads. The period greatest activity (1800 hr.) coincides maximum flower opening. T maze experiments showed that small mammals, given choice typically bird-pollinated having characteristics flowers pollinated always foraged latter. That can is indicated their behavior while captivity, morphological "fit" selective reduced seed set (50% 95%) were excluded was limited insects (mostly honey bees). ne~ctar produced 'The study supported part NSF grant (DEB 78-11624). We thank B. Albee, L. Arnow, H. G. I. Baker, P. Cox, V. Grant, S. D. Hopper, Raven, Turner helpful comments manuscript. People too numerous mention individually assisted research, particular staffs Karoo Botanic Garden, Kirstenbosch Garden its director Prof. Brian Rycroft. curator Mr. Bruce Bayer, provided generous logistical field assistance engaged stimulating discussions problem from inception. Peter Connie Smits offered unsurpassed hospitality Peter's keen photographic sense invaluable. Drs. Nick Marie Strickland, Dr. Derek Mitchell, J. U. M. Jarvis, all Cape Town University, as well Fred Kruger, South African Forestry Research Institute, Pretoria, various capacities. late du Plesis his wife, Thelma, access unparalleled sites Jonaskop. Walter Veith, Stellenbosch obtained metabolic rates Aethomys caloric value humiflora nectar; we are also indebted University use scanning electron microscope facility. California, Berkeley, determined acid compositions nectar, continuing interest suggestions. Finally, but not least importantly, Tori Burns, Heidi Fain, Jenny Turner, who survived southeasters! 2 Department Biology, Utah, Salt Lake City, Utah 84112. 3 Claremont, Africa 7735. 4 Present address: Pennsylvania, Philadelphia, Pennsylvania 19104. 5 Biochemistry, Western Cape, Bellville, 7530. ANN. MISSOURI BOT. GARD. 70: 1-31. 1983. This downloaded 157.55.39.153 Mon, 19 Sep 2016 04:55:36 UTC All subject http://about.jstor.org/terms ANNALS OF THE BOTANICAL GARDEN [VOL. 70 meets energy requirements community only several days annually, thus coevolution impossible. Proteas have evolved unilaterally, probably prototypes, possibly response progressive decrease population size. Recent discoveries Neotropics some similar support existence worldwide class such pollinators. first mentioned Kerner (1895, v. 2, p. 230) discussed nearly 50 years ago Porsch (1934, 1935, 1936a, 1936b). further attention, however, until Morcombe (1968) suggested pollinatory relationships proteaceous southwestern Australian flora. Rourke Wiens (1977) reviewed noted floral features convergent Proteaceae adaptations mammals. following year (1978) substantive evidence rodents) two species proteas. Two previous studies presumably bat-pollinated plants, viz., baobab (Bombacaceae) (Coe & Isaac, 1965) Maranthes (Chrysobalanaceae) (Lack, 1977) demonstrated feeding bush babies (Galago crassicaudatus Geoffroy) genets (Genetta tigrina Schreber), respectively. has resulted number publications: Sussman Raven reported arboreal Madagascan mouselike lemurs; Sleumer (1955) Carpenter (1978a) eastern banksias sugar gliders (Petaurus breviceps Waterhouse) indigenous placental bushrat (Rattus fuscipes Waterhouse), Holm Ford, Paton, Forde (1979) commented Armstrong Australia generally. Wiens, Renfree, Wooller Hopper (1980) studied Banksia other marsupial possum (Tarsipes rostratus = T. spenserae Gray). In New World, Prance observed probable cebus monkeys; Janson, Terborgh, Emmons (1981) extensive apparent Bombacaceae Combretaceae Amazon monkeys [including (100 g) pigmy marmoset], opossums, procyonids. Lumer Blakea (Melastomataceae) rodents Costa Rica, Steiner discovered opossums Mabea (Euphorbiaceae) Panama. suggestion rodent Hawaiian Freycinetia (Degener, 1945) apparently error (Cox,