Experiments carried out with travel and salaries
monies provided by the A.F.F. are listed below.
Experiments were performed only in orchards due to the inaccessibility
of racemes of trees in natural locations. Furthermore, since the
refugia of wild macadamia trees are small, they no longer represent
"natural" situations.
l. Pollinating insect diversity and abundance in 11
macadamia orchards in Queensland and NSW.
The eleven orchard sites surveyed for diversity and
abundance of pollinating insects are shown on Fig
1.
A mean of greater than 90% of macadamia flower visitors belonged
to two species of social bees, honey bees (Apis mellifera)
or Trigona bees (Trigona carbonaria). The abundance of
insects other than honey bees was correlated with the extent of
surrounding vegetation.
2. Pollinating insect diversity, abundance and behaviour
at one site (Closeburn) for the full duration of the flowering season.
Honey bees and Trigona bees were present through the
entire flowering season of macadamia. Other insects were rare at
the beginning of the flowering season (July) but common later in
the flowering season (October).
Results show that whereas honey bees forage for nectar, Trigona
bees visit the flowers mainly for pollen. This results in Trigona
bees coming into contact with the stigma of the macadamia flower
more often than honey bees, suggesting they are more efficient pollinators.
3. Foraging preferences of the two major pollinating
insects (viz honey bees and Trigona bees) to determine which bee
species visit racemes in sunny and/or shady positions and on both
heavily and lightly flowering trees.
No statistical analysis is yet completed but it appears
that both honey bees and Trigona bees forage equally actively in
open sunny positions and shady positions.
4. Relative pollinator efficiency of the two major
insect visitors by covering racemes with a wire mesh that allows
only the smaller Trigona bees to forage and assessing the resulting
initial nut set and final nut set.
Macadamia racemes visited only by Trigona bees showed
high initial nut set suggesting these bees are efficient pollinators.
Data for final nut set is not yet available.
5. Determining the relationship between the number
of bee visits and the initial and final nut set by bagging racemes
and removing the bags for varying periods each day for the full
duration of raceme life.
Treatments that resulted in higher levels of insect
visitation also had higher initial nut set. Data for final nut set
is not yet available.
B. EXPENDITURE STATEMENT
Salaries (for period 7 July 1987 to 30 Oct 1987)
345 hours at $9.52 / hour
$3284.24
Travel 1255 km at $0.21 / km
$263.60
Total expenditure
$3547.84
Uncommitted funds
$32.16
Work will continue in 1988 on aspects 4 and 5 of research. Further
transport funds will be required. Forty trips to Closeburn at 8Okm/trip
will cost at least $640. If there is any chance of further funding
from the Australian Flora Foundation it would be put to good use
and we would be very grateful.
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