Analysis Of Pollen Loads Research Articles

Pollination Ecology of Vernal Angiosperms

Pollination interrelationships of vernal, herbaceous angiosperms in a deciduous forest in southwestern Ohio, USA, were studied for 3 seasons with particular emphasis on phonological integration of the bionomics of flowers and the annual colonies of Bombus pollinators. Except for Corydalis flavula, all plants were insect or bird-dependent for pollination. In general, the spectrum of Bombus species on flowers was related to time of emergence from hibernation of bumblebee queens, sequence of anthesis, depth of nectariferous tubes or spurs of flowers in relation to measured proboscis lengths of bumblebee foragers, and site preference for pollinator nesting and foraging. Spectral reflectance from corollas measured spectrophotometrically indicated general correspondence of corolla color and visual spectra of pollinators. Analysis of nectars by refractometry and thin-layer chromatography revealed no preference of pollinators for particular sugars in nectar nor for particular sugar concentrations. Such preference is considered to be related to availability and abundance of nectar. As determined by analysis of corbicular pollen loads from pollinators, fidelity of bumblebee queens to specific flowers was 60%. Only 9.5% of 1457 queens investigated foraged for pollen. Close correspondence of floral form and insect behavior was indentified by means of cinematography and stereophotographic analysis of pollinator activity. Except for possible interactions between Dicentra species and Corydalis, no clear evidence for competition between pollinators for forage or between plant species for pollinators was observed. The pollination system of the vernal flora is considered to reflect a high degree of coadaptive integration of phenological, ethological, and morphological phenomena in dynamic homeostasis involving constant, but very gradual, change.

THE POLLINATION ECOLOGY OF PEDICULARIS ON MOUNT RAINIER

Six native species of Pedicularis in Mount Rainier National Park in Washington State were studied for their reproductive relationships with animal pollinators. Cinematographic and stereophotographic records revealed pollination of the nectariferous P. bracteosa and P. rainierensis by upright, nectar‐foraging queens and workers of five bumblebee (Bombus Latr.) species and by inverted workers scraping pollen from anthers concealed within the corolla galea. The nectarless, rostrate flowers of P. contorta, P. groenlandica, P. ornithorhyncha, and P. racemosa were pollinated by pollen‐foraging workers and occasional queens virbrating pollen from concealed anthers. Insect exclosure methods revealed complete absence of fruiting in the absence of insects, and pollinator collections further indicate obligate dependence of the plants upon bumblebees for their sexual reproduction. Analysis of corbicular pollen loads from pollinators suggested that pollinator species are not monolectic but that individual pollinators range from monolectic to polylectic. Measurements indicated limited correlations between lengths of corolla tubes and tongues of nectar‐foraging insects. Each nectarless Pedicularis species occupied a different, specific habitat, but P. bracteosa and the endemic P. rainierensis were sympatric in part. Each species had a unique spectral reflectance pattern from the corolla. Proximity of habitats and overlap of blooming periods of all Pedicularis species eliminate the possibility of contemporary geographic or phenological reproductive isolation. It is suggested that behavioral interactions of the plants and their insect pollinators may have been instrumental in the past in reproductively isolating these species, hybrids of which are unknown.

The Pollination Ecology of Pedicularis on Mount Rainier

Six native species of Pedicularis in Mount Rainier National Park in Washington State were studied for their reproductive relationships with animal pollinators. Cinematographic and stereophotographic records revealed pollination of the nectariferous P. bracteosa and P. rainierensis by upright, nectar-foraging queens and workers of five bumblebee (Bombus Latr.) species and by inverted workers scraping pollen from anthers concealed within the corolla galea. The nectarless, rostrate flowers of P. contorta, P. groenlandica, P. ornithorhyncha, and P. racemosa were pollinated by pollen-foraging workers and occasional queens virbrating pollen from concealed anthers. Insect exclosure methods revealed complete absence of fruiting in the absence of insects, and pollinator collections further indicate obligate dependence of the plants upon bumblebees for their sexual reproduction. Analysis of corbicular pollen loads from pollinators suggested that pollinator species are not monolectic but that individual pollinators range from monolectic to polylectic. Measurements indicated limited correlations between lengths of corolla tubes and tongues of nectar-foraging insects. Each nectarless Pedicularis species occupied a different, specific habitat, but P. bracteosa and the endemic P. rainierensis were sympatric in part. Each species had a unique spectral reflectance pattern from the corolla. Proximity of habitats and overlap of blooming periods of all Pedicularis species eliminate the possibility of contemporary geographic or phenological reproductive isolation. It is suggested that behavioral interactions of the plants and their insect pollinators may have been instrumental in the past in reproductively isolating these species, hybrids of which are unknown.

An Analysis of Pollen Loads of Honey Bees from Kangra, India

Abstract Thirty-nine bee pollen loads collected in Kangra, were analyzed, during a period of three months. Eight loads were found to be mixed and the rest unifloral. In all, twenty pollen types were recognised in the loads, which included some of the anemophilous types, namely, Gramineae, Cyperaceae, Palmae, Chenopodiaceae and Urticaceae.