35 / 82
were dish-bowl blossoms wiih more or less exposed nectar: shallow flowers of
Filipen-
chiJo
(33.3% of the pollen loads)..
Patentilia, Gettm. Veratrum,
Brassicaceae or dense flat
inflorescences with ‘"tube" effect e. g. Asteraceae (Table 3a, Fig. 3). The pollen grains
from "bell ’
Vacemhun —
60.0% of the pollen loads and
Campanula
—40.0% of the pollen
loads as well as "gullet" —
Pediculans
(33.3% of the pollen loads), and "flag" flowers
were presented even better then those of the "dish-bowl" plants considering the
abundance if the blssom types in the area. The pollen grains o f the "bells" were adequate
to the plants flowering around but the "flag" and "gullet"' plants were presented better in
the pollen baskets rather than in the field. Even
Aconitum
and
Rhinanthus
were not
recorded in the close vicinity, which indicates wide area of foraging (Table 3).
Genttana
pollen quantity varied within species and conspecilic individuals bumblebees:
Boinbus
pratonun (n
* 9, mean = 64.4%, min = 3% max = 100%):
B. sylvctrum
(/; = 9, mean -
83.3%, min = 16.6% max ~ 99.6%):
Вambits pvrenaem (n ~
7. mean = 71.8'%. min =
3.2% max - 99.7%); etc. (Tables 7 and 8).
Gentiana asclepiadea
L.
The main pollinators were workers and to some extent males bumblebees. They
were the most effective though not the most numerous pollinators - 10.7% of all flower
visitors (Kozuharova, 2004).
Bombus agronun
and
B. hortorum
dominated (Table 1).
Nectar collectors were 94% o f all bumblebees. Pollen collecting bumblebees usually
sucked as well nectar in the same flower (75% o f the visits). In addition, bumblebees
brushed the pollen adhered on their bodies into the pollen baskets on their way between
the flowers.
The high flower constancy of bumblebees workers observed in the fields
correlated with a high percentage of
Gentiana-type
pollen found in their pollen baskets
(mean = 65,2%, min = 0% max =100%, Table 7). Their "minors” were 1-8 plant species
(Table 8). These plants were more or less abundant in the area (Table 4, 4a). These were
dish-bowl blossoms with more or less exposed nectar: shallow flowers of
Hypericum
(47.4% of the pollen loads),
Verbascum,
Apiaceae, Brassicaceae or dense flat
inflorescences with "tube” effect e. g. Asteraceae - 63,2% of the pollen loads contained
1-4 pollen types from this family, Dipsaceae - 263%, (Table 4a). The pollen grains of
Tnjblimn -
"flag” blossoms were presented quite well - 36.8% of the pollen loads, while
in the field this was not the most abundant species (Table 4). The quantity of
Gentiana
pollen varied within species and conspecific individuals bumblebees:
Bombas terresiris
(/? - 5, mean = 76.5%. mill = 11.5% max = 99%);
Bombas praiorum (n
= 4, mean -
34.8%, min = 0% max - 100% both workers foraged on
G. asclepiadea
occasionally
considering their pollen loads. (Figs. 2 and 3);
Bombas agroram (n ~
4, mean = 71.5%,
miu = 36% max = 99%);
Bombas hortorum (n
= 3, mean = 67.9%. min = 50% max ~
83%); etc. (Tables 7 and 8). The pollen loads of a queen and a worker
B. praiorum
contained
Aconiturn-type
pollen, which indicated a wide foraging perimeter, as these
plants did not bloom in the neighborhood. The presence o f
Vaccinium
and
Pedieularls -
both species out o f flower could be due to contamination in the nest as these plants were
already not in flower for at least a month.
Электронная Научная СельскоХозяйственная Библиотека