pollination intensity and potential seed set in passiflora vitifolia.initial seed set and fruit set were pollen-limited in a costa rican population of passiflora vitifolia, a self-incompatible species with 200-350 ovules per flower. pollination intensity was measured by counting the number of allogamous pollen grains on stigmas of the large one-day flowers. hand-pollinations demonstrated that 25-50 pollen grains are required for fruit set, and >450 are needed for maximum seed set, with a pollen:seed ratio of about 1.6:1.0. hummingbirds (phaethornis superciliosus) ...198228311238
effect of nectar secretion rate on pollination success of passiflora coccinea (passifloraceae) in the central amazon.the pollination of passiflora coccinea by the hummingbird phaethornis superciliosus was studied in central amazon, brazil. we hypothesized that a greater nectar secretion rate (nsr) increases the pollination success of single flowers through ph. superciliosus visiting behavior. for control flowers, nsr was an increasing function of flower base diameter (fbd). the total number of ph. superciliosus probes per flower was an increasing function of fbd. additionally, deposition of pollen on stigmas i ...200616906307
eye morphology and retinal topography in hummingbirds (trochilidae: aves).hummingbirds are a group of small, highly specialized birds that display a range of adaptations to their nectarivorous lifestyle. vision plays a key role in hummingbird feeding and hovering behaviours, yet very little is known about the visual systems of these birds. in this study, we measured eye morphology in 5 hummingbird species. for 2 of these species, we used stereology and retinal whole mounts to study the topographic distribution of neurons in the ganglion cell layer. eye morphology (exp ...201526587582
hermit to king, or hermit to all: multiple transitions to crab-like forms from hermit crab ancestors.the anomura presents the greatest degree of morphological disparity in the decapod crustacea, with body forms ranging from the symmetrical and asymmetrical hermit crabs to squat lobsters and king crabs. the phylogeny of the anomurans has been fraught with controversy. recent debate has focused primarily on the phenomenon of carcinization, the evolution of crab-like form from a non-crab-like ancestor, focused chiefly on derivation of king crabs from asymmetrical hermit crabs--the "hermit to king" ...201121835822
temporal and microclimatic partitioning of the floral resources of justicia aurea amongst a concourse of pollen vectors and nectar robbers.the flowers of justicia aurea, morphologically characteristic of ornithophily, attracted a diverse array of foragers where they occurred as a dense stand in the tropical forests at la selva, costa rica, and so provided an arena for this study of competition and coexistence. two hummingbird species (phaethornis superciliosus and campylopterus hemileucurus) visited the flowers legally early in the morning, and defended the nectar resource; a third smaller bird (p. longuemareus) foraged for nectar ...198128310312
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