Allen Dick asks about the interaction between leafcutter bees and honey
bees on canola.
 
Leafcutter bees usually forage only 40 to 50 feet from their nest boards
according to a prodigious amount of work done on the bee by the state
university here.  Leafcutters are used here for alfalfa seed production.
Honeybees in large numbers are placed all over the seed production area to
produce honey.  The research seems to show that honeybees can gather nectar
from the flower up to the point that the flower is pollinated, or tripped,
by the leafcutter bee.  Nectar production stops at this time.  Honeybees
only trip about 10 percent of the bloom they visit (as I recall the
literature) because they avoid getting hit by the trigger which scatters
pollen on the pollinator.  The educated honey bee goes into the side of the
bloom to get the nectar.
 
Now, about the interaction of the two bees.  My observations suggest that
leafcutters do not forage well in the immediate vicinity of an apiary if it
is placed alongside the field because of the heavy honeybee flight
activity.  This has been interpreted by some to indicate that honeybees
"push" leafcutters from the area thus reducing pollination and seed set.  I
have never observed "pushing" or direct interactions between the two bees.
But I have observed that where honeybees are in large numbers 150-300 feet
around an apiary, leafcutters tend to stay away.  I have never observed a
situation where a leafcutter board shelter was placed next to an apiary, or
vice versa, so I can't describe bee interaction in that kind of situation.
The research data shows that significantly lower amounts of seed are
harvested on that portion of the field next to the honeybee apiary.
Observations also show that if the hives are placed away from the fields by
several hundred feet, preferably several hundred yards (metres), that
honeybees spread out to forage and both bees can be seen in the alfalfa.
 
Leafcutter bees do have a strain of chalkbrood very similar to honeybee
chalkbrood but they are not the same.  They are not known to have other
diseases in common.
 
James C. Bach
WSDA State Apiarist
Yakima WA
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