Pollenkörner am Bienenkörper nach der Bestäubung verschiedener Kohlsorten (Brassica oleracea)

Abstract - Pollen grains adhering to bodies of honeybees after cole (Brassica oleracea) crop pollination
From 1983 to 1987, the occurrence of pollen grains on honeybee bodies during and after pollination of cole crops and the viability of these pollen grains were observed. The objective of the study was to determine the shortest time lapse after which the same group of honeybees could be utilized for pollination of genetically related material without the risk of causing undesirable cross-fertilization. The honeybees were marked while at work on flowers. The morning of the following day, they were caught on combs before leaving the hive (tested bees). Using a stereomicroscope, the occurrence of pollen grains on their bodies was ascertained and the loci of occurrence and the mode of pollen deposition were recorded; details were represented in drawings and photographs made with the use of a REM Tesla BS 300 microscope. The honeybees used as controls were examined in the same way immediately after they were caught on flowers. Pollen grains on bodies of honeybees were much less numerous on tested bees than on control ones. The figures show the localization of pollen grains: head (figs 1-3), ventral face of thorax (fig 4-6), pairs of legs (figs 7-9, wing (fig 10 and 11), 5th sternit (fig 12). The viability of pollen grains found on the bodies of honeybees was tested on individuals caught on flowers; groups of five were isolated for 1, 3, 5, 15 and 22 hours. There after, the pollen was wiped from their bodies and its viability assessed by the proof of active esterases due to fluorochromatic reaction, following the method described by Heslop-Harrison and Heslop-Harrison (1970). Pollen removed from anthers and stored in Petri dishes was also tested at identical time intervals. From 1985 to 1987, honeybees caught on flowers were color-marked and taken from the hive the following day for examination. Viability of pollen grains decreased with time away from anthers, the decline being more rapid (P = 0.01) in pollen on bodies of honeybees (fig 13: columns with vertical bars) than it was in pollen from anthers (fig 13: columns with horizontal bars). The viability of pollen grains found on the bodies of honeybees isolated for 15-22 hours outside the hive was always higher (9-20%) than it was on bees taken from the hive (0.5-1.5%), the former carrying appreciably larger amounts of pollen grains than the latter. It is concluded that, in the studied plant material, transportation of viable pollen carried on bodies of honeybees from the hive to the stigmas of flowers is highly improbable, because of the low germinability of the pollen grains and their deposition on inaccessible parts of the honeybee body.