ST'JDIES ON THE INSEOT FAUNA ON SCOTCH BROOM
143
TABLE XXX
Surviuccl of eggu, larvae and adulfa of A. immune at lour
temperaturea ( Wiliiame, 1966)
MWll
Minimum
Time of
%
temperature
temperature
e x p u r e
survival
StaBe
"C
"C
( b y e )
Adults
- 9.8
-11.1
5
85
Adulur
- 15.5
-17.3
5
0
Adults
-13.2
- 16.2
1
75
Adulta
- 15.2
- 18.1
1
5
Larvae
- 7.7
- 9.3
5
100
Larvae
- 13.2
-15.2
5
0
Larvae
- 13.2
- 16.2
1
30
Larvae
- 16.2
- 18.2
1
10
Eggs
- 13.2
- 16.2
1
60
Eggs
--16*2
-18.1
1
0
The temperatures in the grass tussocks are not subject to the same
extremes as those of the surrounding air (Luff, 1966) and it has been
shown by Danthanarayana (1965) that the temperature in broom litter
never fell below O-S'C, even in the severe winter of 1962-63. Thus, it
appears that by movements to the tussocks or to broom litter A. immune
could survive even more rigorous winters.
3. Flight activity
In the field A. immune adults were seen to fly at a height of 1.6-2 m
above the ground and occasionally to alight on a plant from a height of
3 m. However, extremely few individuals were caught in the suction
traps and this is probably related to the alary dimorphism in this
species. Over S6Y0 of the weevils examined were brachypterous, the
percentage of alate forms being only 13.6. The proportion of alate to
brachypterous forms was significantly greater in the females than in
the males but the adults copulate immediately after emergence and
this ensures that they are fertilised before they emigrate.
4. Hymewpterowr Zjarasitea of A. immune adults
From 1963 to 1966 from 1-4 to 25% A . immune adults were parasitiaed by a braconid. The parmite was identified by Dr R. D. Eady as
a Euphorine belonging to the Microctonua aethiopa (Nees) -aecaZis Hal.
complex, fitting the M . aethiops end of the complex rather better than
the sealis end. The same species was also bred from adults of the clover
weevil, Apion dichroum Bedel. and this is the fist record of a hymenopteroua parasite attacking a n adult of any A p i m species. M . aethiops
(Nees) is known to be a parmite of 8 i t m (Loan and Holdaway, 1901).
143
TABLE XXX
Surviuccl of eggu, larvae and adulfa of A. immune at lour
temperaturea ( Wiliiame, 1966)
MWll
Minimum
Time of
%
temperature
temperature
e x p u r e
survival
StaBe
"C
"C
( b y e )
Adults
- 9.8
-11.1
5
85
Adulur
- 15.5
-17.3
5
0
Adults
-13.2
- 16.2
1
75
Adulta
- 15.2
- 18.1
1
5
Larvae
- 7.7
- 9.3
5
100
Larvae
- 13.2
-15.2
5
0
Larvae
- 13.2
- 16.2
1
30
Larvae
- 16.2
- 18.2
1
10
Eggs
- 13.2
- 16.2
1
60
Eggs
--16*2
-18.1
1
0
The temperatures in the grass tussocks are not subject to the same
extremes as those of the surrounding air (Luff, 1966) and it has been
shown by Danthanarayana (1965) that the temperature in broom litter
never fell below O-S'C, even in the severe winter of 1962-63. Thus, it
appears that by movements to the tussocks or to broom litter A. immune
could survive even more rigorous winters.
3. Flight activity
In the field A. immune adults were seen to fly at a height of 1.6-2 m
above the ground and occasionally to alight on a plant from a height of
3 m. However, extremely few individuals were caught in the suction
traps and this is probably related to the alary dimorphism in this
species. Over S6Y0 of the weevils examined were brachypterous, the
percentage of alate forms being only 13.6. The proportion of alate to
brachypterous forms was significantly greater in the females than in
the males but the adults copulate immediately after emergence and
this ensures that they are fertilised before they emigrate.
4. Hymewpterowr Zjarasitea of A. immune adults
From 1963 to 1966 from 1-4 to 25% A . immune adults were parasitiaed by a braconid. The parmite was identified by Dr R. D. Eady as
a Euphorine belonging to the Microctonua aethiopa (Nees) -aecaZis Hal.
complex, fitting the M . aethiops end of the complex rather better than
the sealis end. The same species was also bred from adults of the clover
weevil, Apion dichroum Bedel. and this is the fist record of a hymenopteroua parasite attacking a n adult of any A p i m species. M . aethiops
(Nees) is known to be a parmite of 8 i t m (Loan and Holdaway, 1901).