Hint
# 3 - The Hive Mat
Worth a Try?
…. the Mercer
Mat.
Most
beekeepers insert some kind of inner cover between the top super
and the hive lid. Although used overseas, inner covers or ceilings
made of plywood or masonite with a rim of battens all round to
provide beespace above top bars are not normally used in Australia.
However, mats made of plastic, floor vinyl, carpet, hessian
and other similar materials are commonly used here.
Various experienced Australian beekeepers champion the
use of hive mats in a variety of materials and designs.
Our
own Cec Mercer uses and recommends a mat of his own design. The
Mercer Mat can be made easily and inexpensively by any beekeeper.
It is specifically designed to provide appropriate ventilation
to reduce excessive moisture in the hive, but it also useful in:
·
deterring the building
of burr comb in the hive lid;
·
encouraging the bees
not to propolise ventilation holes in the lid; and
·
assisting winter storage
of empty drawn comb.
The
Mercer Mat is a sheet of plastic, cut to allow air to rise on
all four edges of the mat as well as up between the top bars of
the central two frames of the top super.
The mat for the standard 8 frame hive should be no wider
than 28cm, nor longer than 43cm. The rectangular sheet is then folded into quarters
and a section cut out of the folded edge such that, when the sheet
is opened out, an elongated oval hole is made in the sheet. The resultant hole should be 2 to 3 cm across
and 15 to 20 cm long.
A
wide variety of plastic sheeting can be used to make these mats. However, any non-absorbent sheeting that can be cut to the appropriate
shape may be used. There
is advantage in using a material that is easily obtainable, easily
cut and cheap.
The mat is laid
across the top of the frames under the lid, providing a ventilation
gap all around and between the middle top bars.
The main principle
behind the design of the Mercer Mat is that the greatest danger
to the health of the colony in winter is not cold, but excessive
moisture. The cluster
is the effective temperature management tool of the wintering
colony; but wetting of
the cluster by condensation of moisture expired by the bees can
greatly reduce that effectiveness.
The central opening in the mat allows the colony to regulate
ventilation of the winter cluster and better control humidity
and temperature within the cluster. The design assumes that the
hive lid is fitted with ventilation holes to the outside.
The
mat is also effective in minimising the development of burr comb
in the hive lid. Comb will not be built in the area between the
mat and the lid unless the beekeeper is slow in adding additional
supers when a flow is in progress and the colony runs out of room
below the mat.
Bees
will often block or reduce the size of ventilation holes in the
hive lid with propolis; however, when the Mercer mat is used it
is very rare for those ventilation holes to be even partially
propolised.
The
mat is particularly useful when supers of extracted comb are stored
on the hives over winter. Rather
than treating stored empty combs throughout the winter with PDB
or Phostoxin, one super of empty comb can be stored on each hive,
above a mat. The bees will not occupy the stored frames in normal
circumstances but, in warmer moments over the winter, will venture
into the stored box and generally keep it free of wax moth. If an unexpected flow occurs in early Spring,
the bees will use the stored combs if they run out of space below
the mat.
Paul Hooper
This hint appeared
first in the April 2002 newsletter of the Beekeepers Association
of the ACT.
