. Bulletin. Science; Natural history; Natural history. Figure 1. Flowers of Columnea florida depicting front and side views (a) and lateral exposed views of the protandrous condition with the anthers extended and stigma closed (b) and the anthers withdrawn and stigma receptive (c). observed primarily during the morning hours, from 0530 to 1200, since hummingbird activity was greatest during that time. In 1970, a survey of C. florida in the area re- vealed that flowering had not begun. The plants chosen for observation were, therefore, somewhat modified to simulate natural morphological char- a
. Bulletin. Science; Natural history; Natural history. Figure 1. Flowers of Columnea florida depicting front and side views (a) and lateral exposed views of the protandrous condition with the anthers extended and stigma closed (b) and the anthers withdrawn and stigma receptive (c). observed primarily during the morning hours, from 0530 to 1200, since hummingbird activity was greatest during that time. In 1970, a survey of C. florida in the area re- vealed that flowering had not begun. The plants chosen for observation were, therefore, somewhat modified to simulate natural morphological char- acteristics during the peak flowering period, as determined from the Flora of Costa Rica (Stand- ley, 1937). On 30 July, two plants were selected and a pair of red spots, cut from orange-red sur- veyor's tape, was glued onto the leaves in the position where they normally appear. Yellow flow- ers from Heliconia sp. were trimmed to simulate the flower size of C. florida and inserted in the axils of the leaves. In 1972, observations were made on individuals of C. florida which were in bloom so modifications were unnecessary. RESULTS AND DISCUSSION During the observation period in 1970, only two species of hummingbirds, the Little Hermit (Phae- thornis longuemareus—eight observations) and the Green-Crowned Brilliant (Heiiodoxa jacula— four observations) visited C. florida. No other pollinators were noted on or near the flowers. Two behavioral patterns emerged when the birds spotted the conspicuous red pattern on the leaves. Two Little Hermits hovered directly above the two red spots and after 2-4 seconds dipped quickly under the large leaves and approached the axillary flowers. At this point the bill was inserted into the "dummy" flowers and the visitation com- pleted. All other birds of both species followed a similar behavioral pattern but did not fly directly to the flowers. Instead these individuals appeared to discern the red cue, but did not perceive the. Please
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