Abstract:
It is well known that Cataseturn flowers are pollinated
by male euglossine orchid bees (Criiger 1865, Darwin
1877, Dodson 1962, Pijl and Dodson 1966). The bees
remove several chemicals from Cataseturn (and other
orchid) flowers with brushes on their front feet, transfer
the chemicals to special grooves in their hind tibiae, and
use them for unknown purposes in their own
physiology (Dodson et al. 1969). Degradation products
of the chemicals appear in mandibular gland secretions
(N. H. Williams pers. comm.) but the secretions are of
unknown function. Just as with other orchids pollinated
by euglossine orchid-bees no one has examined the
quantities of bees that visit Catasetum inflorescences in
a natural habitat (see Williams 1978 for a thorough
bibliography of orchid-bee papers). Here I describe the
visitors and pollinators at two sequential Sflowered
female inflorescences on one ~atasetum maculatum
orchid.
The central axis so as to produce approximately equal
numbers of degrees between each of the 5 lines of approach.
The buds of the first inflorescence began to
open on 15 May 1979, the first odors were produced by
the most proximal flower on 18 May, and the five open
unpollinated flowers ceased odor production after the
morning of 27 May. The buds of the second inflorescence
did the same; the most proximal was the first
flower to attract bees (10 July). The last day of attraction
was 15 July, and the pollinated flowers stopped
producing odor on the day of pollination.
No rain fell from 21 through 28 May, though the
rainy season had begun on 25 April. The weather was
sunny and breezy. During 10-15 July no rain fell in the
morning but there was afternoon rain and extensive
cloudiness during the day and evening. During the dry
season at SRNP, C. maculatum is leafless and does not
bear flowers.
