Variation in the colour of the keel petals in Lotus corniculatus L. 3. Pollination, herbivory and seed production

Abstract

The response of pollinators to the pseudo-cryptic polymorphism of dark/light keel colour in Lotus corniculutus has been studied experimentally. Some evidence was obtained that the bumble-bees Bombus lapidarius and B. terrestris forage more dark-keeled flowers in dull and overcast conditions than in bright sunlight.The distribution of herbivorous insects within the flowers of L. corniculatus suggests that they do not distinguish between the keel colour phenotypes.The entire seed production of pre-marked plants growing at two sites was recovered. Analysis of the data obtained from one site showed that the phenotypes did not differ significantly in any of the following characteristics: pods produced, seeds produced, seeds per pod, seed herbivores, seed herbivores per pod, damaged seeds, and germination patterns. At the second site no germination trials were effected, but even more closely similar values for seed production and overall seed herbivory of the two keel colour phenotypes were obtained.At the latter site the herbivorous wasp Eurytoma platyptera was commoner in the pods of light-keeled plants and light-keeled plants produced more seeds than the dark-keeled plants later in the season even though light-keeled plants tend to flower earlier.

The Role of Herbivores in the Maintenance of a Flower Color Polymorphism in Wild Radish

“…Flower color has traditionally been viewed as a trait that is essential in attracting certain suites of pollinators (Grant 1950, Faegri and van der Pijl 1979, Proctor et al 1996. Although many studies have found selective foraging by pollinators for specific color morphs (e.g., Levin 1972, Mogford 1974a, Kay 1976, Hannan 1981, Waser and Price 1981, Brown and Clegg 1984, Jones et al 1986, Stanton 1987a, Stanton et al 1989, Odell et al 1999, Comba et al 2000, Gigord et al 2001, Jones and Reithel 2001, other studies have found pollinators indifferent to flower color variation within a species (e.g., Ernst 1987, Wolfe 1993, Schemske and Bierzychudek 2001. Many pollinator-centric hypotheses have been proposed as factors maintaining flower color polymorphisms, including color preferences and the constancy of specific suites of pollinators to certain color morphs (Stanton 1987a, Jones andReithel 2001).…”

Interspecific Hybridization between Coreopsis leavenworthii and Coreopsis tinctoria Differently Affected Growth, Development, and Reproduction of Their Progeny

“…Previous studies have shown that flower colors could play important roles in attracting or repelling certain pollinators to visit and pollinate flowers. Jones et al (1986) showed that some bees preferred the dark knee color over light color in lotus (Lotus corniculatus L.) for foraging and pollination. Reportedly, white corolla color could limit hybridization of Phlox pilosa L. with pink-flowered Phlox glaberrima L. (Levin and Schaal, 1970).…”

The keel colour polymorphism in Lotus corniculatus L.: differences in internal flower temperatures

“…We are planning an experiment where the fecundities of open-pollinated plants are tested in mixed array m rephcare north and south facing plots. In previously reported experiments, the relative fecundity of dark-and light-keeled plants was tested under uniform conditions and failed to show any temperature related effects (Jones & Crawford, 1977;Jones et al, 1986).…”

“…There is an interesting report that individuals of Bombus lapidarius L. (but not B. terrestris L.) preferentially forage dark-keeled flowers in overcast weather when presented with both morphs at equal frequency in random array, but not when in a systematic array (Jones et al, 1986).…”

“…A number of other fitness parameters have been tested for their association with the keel colour polymorphism, for instance winter survival (Jones & Crawford, 1977;herbivory (Compton, Beesley & Jones, 1983;Jones et al, 1986); fruit and seed set, and seed germination ; pollination ; competition with other vegetation (Compton, Beesley & Jones, 1988); and flowering time (Crawford & Jones, 1988).…”