Ecological separation in foraging schedule and food type between pollinators of the California wildflower, Clarkia xantiana ssp. xantiana

Georgia Hart; Vince Eckhart

doi:10.26786/1920-7603(2010)2

Authors

Georgia Hart
Vince Eckhart

DOI:

https://doi.org/10.26786/1920-7603(2010)2

Keywords:

Pollination, resource partitioning, coexistence, foraging, solitary bees, nectar

Abstract

The co-occurrence of several dimensions of resource separation between coexisting consumers strengthens the hypothesis that the separation arose from and/or ameliorates interspecific competition. The two most common pollinators of the California endemic plant Clarkia xantiana ssp. xantiana (Onagraceae), the bees Hesperapis regularis (Mellitidae) and Lasioglossum pullilabre (Halictidae), are known to partition flower resources by flower colour. Here we asked whether H. regularis and L. pullilabre also partition flower resources by diurnal foraging schedule and by food type (pollen versus nectar). We also quantified diurnal patterns of nectar availability, expected to be related to foraging schedules and forager responses to flower colour. The diurnal schedules of the two species differed distinctly and significantly. The majority of L. pullilabre foraging visits occurred before midday, while the majority of H. regularis visits occurred afterwards. The two species foraged for alternative food types at significantly different frequencies—nectar and pollen approximately equally frequently for H. regularis, pollen almost exclusively for L. pullilabre. Nectar standing crop declined with time of day, but it did not clearly reflect or explain previously identified colour-morph preferences. The major pollinators of C. xantiana ssp. xantiana exhibit multiple forms of ecological separation that likely reduce the intensity of competition for floral resources.

References

Amarasekare P (2003) Competitive coexistence in spatially structured environments: a synthesis. Ecology Letters 61:1109-1122 DOI: https://doi.org/10.1046/j.1461-0248.2003.00530.x

Burdick DJ, Torchio PF (1959) Notes on the biology of Hesperapis regularis (Cresson) (Hymenoptera: Melittidae). Journal of the Kansas Entomological Society 32:83-87

Cotton PA (1998) Temporal partitioning of a floral resource by territorial hummingbirds. Ibis 140:647-653 DOI: https://doi.org/10.1111/j.1474-919X.1998.tb04710.x

Eckhart VM (1992) Spatio-temporal variation in abundance and variation in foraging behaviour of the pollinators of gynodioecious Phacelia linearis (Hydrophyllaceae). Oikos 64: 573-586 DOI: https://doi.org/10.2307/3545177

Eckhart VM, Geber MA (1999) Character variation and geographic distribution of Clarkia xantiana A Gray (Onagraceae): Flowers and phenology distinguish two subspecies. Madroño 46:117-125

Eckhart VM, Rushing NC, Hart GM, Hansen JD (2006) Frequency dependent pollinator foraging in polymorphic Clarkia xantiana ssp. xantiana populations: implications for flower colour evolution and pollinator coexistence. Oikos 112:412-421 DOI: https://doi.org/10.1111/j.0030-1299.2006.14289.x

Emms SK, Arnold ML (2000) Site-to-site differences in pollinator visitation patterns in a Louisiana Iris hybrid zone. Oikos 91:568-578 DOI: https://doi.org/10.1034/j.1600-0706.2000.910319.x

Ginsberg HS (1983) Foraging ecology of bees in an old field. Ecology 64:165-175. DOI: https://doi.org/10.2307/1937338

Goulson D (2003) Effects of introduced bees on native ecosystems. Annual Review of Ecology, Evolution and Systematics 34:1-26 DOI: https://doi.org/10.1146/annurev.ecolsys.34.011802.132355

Graham L, Jones KN (1996) Resource partitioning and per-flower foraging efficiency in two bumble bee species. American Midland Naturalist 136:401-406 DOI: https://doi.org/10.2307/2426743

Heinrich B (1976) Resource partitioning among some eusocial insects: bumblebees. Ecology 57:878-889. DOI: https://doi.org/10.2307/1941054

Herrera CM (1995) Microclimate and individual variation in pollinators: Flowering plants are more than their flowers. Ecology 76:1516-1524 DOI: https://doi.org/10.2307/1938153

Inouye DW (1978) Resource partitioning in bumblebees: experimental studies on foraging behaviour. Ecology 59:672-678 DOI: https://doi.org/10.2307/1938769

Kandori I (2002) Diverse visitors with various pollinator importance and temporal change in the important pollinators of Geranium thunbergii (Geraniaceae). Ecological Research 17: 283-294. DOI: https://doi.org/10.1046/j.1440-1703.2002.00488.x

Kronfeld-Shor N, Dayan T (2003) Partitioning of time as an ecological resource. Annual Review of Ecology, Evolution and Systematics 34:153-181 DOI: https://doi.org/10.1146/annurev.ecolsys.34.011802.132435

Lewis H, Lewis ME (1955) The genus Clarkia. University of California Press, Berkeley, CA

Lewis H, Raven PH (1992) New combinations in the genus Clarkia. Madroño 39:163-169

MacSwain JW, Raven PH, Thorp RW (1973) Comparative behaviour of bees and Onagraceae. IV. Clarkia bees of the western United States. University of California Publications in Entomology 70:1-80

McKenna MA, Thomson JD (1988) A technique for sampling and measuring sugar content of small amounts of floral nectar. Ecology 69:1306-1307 DOI: https://doi.org/10.2307/1941289

Medel R. Botto-Mahan C, Kalin-Arroyo M (2003) Pollinator-mediated selection on the nectar guide phenotype in the Andean monkeyflower, Mimulus luteus. Ecology 84:1721-1732 DOI: https://doi.org/10.1890/01-0688

Metterston-Gibbons M (1992) Games nectarivores play. Ecology 73:1913-1915 DOI: https://doi.org/10.2307/1940042

Moeller DA (2004) Facilitative interactions among plants via shared pollinators. Ecology 85:3289-3301 DOI: https://doi.org/10.1890/03-0810

Moeller DA (2005) Pollinator community structure and sources of spatial variation in

plant-pollinator interactions in Clarkia xantiana ssp. xantiana. Oecologia 142:28-37 DOI: https://doi.org/10.1007/s00442-004-1693-1

Moore DM, Lewis H (1965) The evolution of self-pollination in Clarkia xantiana. Evolution 19:104-114 DOI: https://doi.org/10.1111/j.1558-5646.1965.tb01695.x

Paige KN, Whitham TG (1985) Individual and population shifts in flower colour by scarlet gilia: a mechanism for pollinator tracking. Science 227:315-317 DOI: https://doi.org/10.1126/science.227.4684.315

Palmer TM, Stanton ML, Young TP (2003) Competition and coexistence: exploring mechanisms that restrict and maintain diversity within mutualist guilds. The American Naturalist 162:S63-S79 DOI: https://doi.org/10.1086/378682

Pleasants JM (1981) Bumblebee response to variation in nectar availability. Ecology 62:1648-1661 DOI: https://doi.org/10.2307/1941519

Pleasants JM and Zimmerman M (1983) The distribution of standing crop of nectar: what does it really tell us? Oecologia 57:412-414. DOI: https://doi.org/10.1007/BF00377188

Possingham H (1992) Habitat selection by two species of nectarivore: Habitat quality isolines. Ecology 73:1903-1912 DOI: https://doi.org/10.2307/1940041

Real LA (1981) Nectar availability and bee-foraging on Ipomoea (Convolvulaceae). Biotropica Supplement: Reproductive Botany 13:64-69 DOI: https://doi.org/10.2307/2388072

Rodríguez-Gironés MA, Santamaría L (2004) Why are so many bird flowers red? PLOS Biology 2:e350 DOI: https://doi.org/10.1371/journal.pbio.0020350

Runions C J, Geber MA (2000) Evolution of the self-pollinating flower in Clarkia xantiana (Onagraceae). I. Size and development of floral organs. American Journal of Botany 87:1439-1451 DOI: https://doi.org/10.2307/2656870

Schluter D (1986) Character displacement between distantly related taxa? Finches and bees in the Galápagos. The American Naturalist 127:95-102 DOI: https://doi.org/10.1086/284470

Schluter D (2003) Frequency dependent natural selection during character displacement in sticklebacks. Evolution 57:1142-1150 DOI: https://doi.org/10.1111/j.0014-3820.2003.tb00323.x

Steffan-Dewenter I, Tscharntke T (2000) Resource overlap and possible competition between honeybees and wild bees in central Europe. Oecologia 122:288-296 DOI: https://doi.org/10.1007/s004420050034

Stone GN (1993) Endothermy in the solitary bee Anthophora plumipes : independent measures of thermoregulatory ability, costs of warm-up and the role of body size. Journal of Experimental Biology 174:299-320 DOI: https://doi.org/10.1242/jeb.174.1.299

Stone GN, Gilbert F, Willmer PG, Potts S, Semida F, Zalat S (1999) Windows of opportunity and the temporal structuring of foraging activity in a desert solitary bee. Ecological Entomology 21: 208-221. DOI: https://doi.org/10.1046/j.1365-2311.1999.00181.x

Stone GN, Willmer PG (1989) Warm-up rates and body temperatures in bees: the importance of body size, thermal regime, and phylogeny. Journal of Experimental Biology 147: 303-328 DOI: https://doi.org/10.1242/jeb.147.1.303

Stone GN, Willmer P, Nee S (1996) Daily Partitioning of pollinators in an African Acacia community. Proceedings of the Royal Society of London B:1389-1393

Tepedino VJ, Parker FD (1982) Interspecific differences in the relative importance of pollen and nectar to bee species foraging on sunflowers. Environmental Entomology 11:246-250 DOI: https://doi.org/10.1093/ee/11.1.246

Thomson JD (1980) Implications of different sorts of evidence for competition. The American Naturalist 116:719-726 DOI: https://doi.org/10.1086/283662

Thomson JD, Peterson SC, Harder LD (1987) Response of traplining bumble bees to competition experiments: shifts in feeding location and efficiency. Oecologia 71:295-300. DOI: https://doi.org/10.1007/BF00377298

Torres C, Galleto L (1998) Patterns and implications of floral nectar secretion, chemical

composition, removal effects and standing crop in Mandevilla pentlandiana. Botanical Journal of the Linnean Society 127:207-223 DOI: https://doi.org/10.1111/j.1095-8339.1998.tb02098.x

Waser NM, Chittka L, Price MV, Williams N, Ollerton J (1996) Generalization in pollination systems, and why it matters. Ecology 77:279–296. DOI: https://doi.org/10.2307/2265575

Webb CO, Ackerly DD, McPeek MA, Donoghue MJ (2002) Phylogenies and community ecology. Annual Review of Ecology, Evolution and Systematics 33:475-505 DOI: https://doi.org/10.1146/annurev.ecolsys.33.010802.150448

Willmer PG (1983) Thermal constraints on activity patterns in nectar-feeding insects. Ecological Entomology 8:445-469 DOI: https://doi.org/10.1111/j.1365-2311.1983.tb00524.x

Willmer PG (1988) The role of insect water balance in pollination ecology: Xylocopa and Calotropis. Oecologia 76: 430-438 DOI: https://doi.org/10.1007/BF00377039