THE EFFECTS OF FLORAL DISPLAY ON POLLINATOR VISITATION VARY AMONG POPULATIONS OF PHACELIA-LINEARIS (HYDROPHYLLACEAE)

被引:172
作者
ECKHART, VM
机构
[1] Department of Biology, University of Utah, Salt Lake City, 84112, UT
关键词
POLLINATION; PHACELIA-LINEARIS; HYDROPHYLLACEAE; GYNODIOECY; SOLITARY BEES;
D O I
10.1007/BF02214154
中图分类号
Q14 [生态学(生物生态学)];
学科分类号
071012 ; 0713 ;
摘要
Individual plants in gynodioecious populations of Phacelia linearis (Hydrophyllaceae) vary in flower gender, flower size, and flower number. This paper reports the effects of variation in floral display on the visitation behaviour of this species' pollinators (mainly pollen-collecting solitary bees) in several natural and three experimental plant populations, and discusses the results in terms of the consequences for plant fitness. The working hypotheses were: (1) that because female plants do not produce pollen, pollen-collecting insects would visit hermaphrodite plants at a higher rate than female plants and would visit more flowers per hermaphrodite than per female; and (2) that pollinator arrival rate would increase with flower size and flower number, the two main components of visual display. These hypotheses were generally supported, but the effects of floral display on pollinator visitation varied substantially among plant populations. Hermaphrodites received significantly higher rates of pollinator arrivals and significantly higher rates of visits to flowers than did females in all experimental populations. Flower size affected arrival rate and flower visit rate positively in natural populations and in two of the three experimental populations. The flower size effect was significant only among female plants in one experimental population, and only among hermaphrodites in another. The effect of flower number on arrival rate was positive and highly significant in natural populations and in all experimental populations. In two out of three experimental populations, insects visited significantly more flowers per hermaphrodite than per female and visited more flowers on many-flowered plants than on few-flowered plants, but neither effect was detected in the third experimental population. Because seed production is not pollen-limited in this species, variation in pollinator visitation behaviour should mainly affect the male reproductive success of hermaphrodite plants. These findings suggest that pollinator-mediated natural selection for floral display in P. linearis varies in space and time.
引用
收藏
页码:370 / 384
页数:15
相关论文
共 51 条
[1]  
Agren J., Elmqvist T., Tunlid A., Pollination by deceit, floral sex ratios and seed set in dioecious Rubus chamaemorus L, Oecologia, 70, pp. 322-38, (1986)
[2]  
Arroyo M.T.K., Raven P.H., The evolution of subdioecy in morphologically gynodioecious species of Fuchsia sect. Encliandra (Onagraceae), Evolution, 29, pp. 500-11, (1975)
[3]  
Atsatt P.R., Rundel P.W., Pollinator maintenance vs. fruit production: Partitioned reproductive effort in subdioecious Fuchsia lycioides, Ann. Miss. Bot. Gard., 69, pp. 199-208, (1982)
[4]  
Ayres M.P., Thomas D.L., Alternative formulations of the mixed-model ANOVA applied to quantitative genetics, Evolution, 42, pp. 221-6, (1990)
[5]  
Bell G., On the function of flowers, Proc. Roy. Soc. Lond. B, 224, pp. 223-65, (1985)
[6]  
Bertin R.I., Paternity in plants, Plant Reproductive Ecology, pp. 30-59, (1988)
[7]  
Bierzychudek P., Pollinators increase the cost of sex by avoiding female flowers, Ecology, 68, pp. 444-7, (1987)
[8]  
Campbell D.R., Measurements of selection in a hermaphrodite plant: Variation in male and female reproductive success, Evolution, 43, pp. 318-34, (1989)
[9]  
Charlesworth D., Charlesworth B., The effect of investment in attractive structures on allocation to male and female function in plants, Evolution, 41, pp. 948-68, (1987)
[10]  
Charnov E.L., Bull J.J., Sex allocation, pollinator attraction, and fruit dispersal in cosexual plants, J. Theor. Biol., 118, pp. 321-5, (1986)