All: Quite a number of times I have heard people speculate that bowls with bees in them are likely to be more attractive to capturing additional bees than
Message 1 of 1
, Jun 25, 2011
Quite a number of times I have heard
people speculate that bowls with bees in them are likely to be more attractive
to capturing additional bees than bowls that do not have any bee in them
I don't believe that this has been tested.
So last week at had some young visiting
researchers (Molly, Cece, and Jacob) who did some interesting tests that
shed at least some light on the topic.
Short Answer .... NO and the probability
may be decreased.
The longer answer is below
3.25 ounce solo souffle bowls painted
fluorescent blue were used.
Transects of bowls were deployed in
lawns and weedy fields on the Beltsville Agriculture Research Center near
Building 308 and one site (Site 3) in a northern Virginia suburban yard
from June 22-24, 2011.
Pairs of bowls were placed so they touched
one another with one bowl having a large bee (Apis or Bombus) place in
it and the other bowl with nothing.
The large bees came from other studies
and were preserved in ethyl alcohol.
Bowls were filled with a mixture of
water with a small amount of Blue Dawn Dishwashing liquid in it.
At a site, A transect of 10 pairs of
bowls was laid out with pairs of bowls 5m apart with treatment cups alternating
from left to right in those pairs along the transect.
Five sites were established.
Bowls were emptied 24 hours after they
were put out and the contents sorted to Genus.
A table showing the number of large bees and small bees captured
at each site (the large bees added to the "With Bee" bowls were
I will send an Excel file separately
Overall nearly twice as many bees were
found in bowls that DID NOT originally have a large bee in them.
This pattern was repeated at each site
with the exception of Site 4 where 4 fewer bees bees were found in the
bowls that did not have bees.
The effect appeared to be greatest in
small bees but relatively few large bees were captured in this study so
this is not completely established.
The effect was the opposite of what
was expected from conversations with people who used bee bowls, the expectation
was that having a bee in a bowl would increase the likelihood of another
bee going into a trap.
As was pointed out by Molly, Cece, and
Jacob, it could be that the alcohol used to preserve the bees that were
initially placed in the bowls had a negative effect, so another round of
tests are planned for this summer using freshly frozen bees instead.
As usual, it is difficult to determine
the universality of these results as each species and sex of bee would
have its own proclivities and preferences for trap types and deployment,
however, it does demonstrate that presence and types of bees in a trap
could influence later capture probabilities which would alter assumptions
regarding comparability of bee composition across locations, particularly
if those locations had very different numbers of bees.
It should also be pointed out that this
test looked at the probability that a bee makes a choice between two bowls
as to which to die in, however, a different and more rigorous test would
be to separate the treatment bowls to see if this pattern repeats when
the choice is not which bowl to die in, but whether to die in a bowl at
Future tests will include looking at
the impacts of the presence of small bees in a trap on the probability
of additional bees being captured and looking at this same test when the
bowls are not adjacent to one another but spaced out so there is no interaction
between bowls with and without bees.
A good student project to repeat
in other geographic locations.
Sam Droege sdroege@...
w 301-497-5840 h 301-390-7759 fax 301-497-5624
USGS Patuxent Wildlife Research Center
BARC-EAST, BLDG 308, RM 124 10300 Balt.
Ave., Beltsville, MD 20705
AWAKE! for Morning in the Bowl of Night
Has flung the Stone that puts the Stars
And Lo! the Hunter of the East has caught
The Sultan's Turret in a Noose of Light.
— Omar Khayyam
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