96
N. WALOFF
A. S P E C I E S CONNECTED WITH T H E BROOM S E E D S
At Sitwood Park two beetles passed some, or all of their immature
stages within the broom weds; a small black BrwAidiw ate* (Marsham)
and a minute greyish weevil Apion fuscirostre Fabricius.
1. Bionomics of beetles
Both species overwinter in the adult stage. The hibernation sites of
Bruchidiua are widely scattered away from broom, those of Apion are
in the broom litter. Bruchidius is a long lived species and hibernates
two winters, but in contrast to the Chrysomelid, Phytodecta, on broom
(Waloff and Richards, 1958) it does not oviposit in the second season.
It was determined experimentally that a third of the adult population
of Bruchidius dies in the first winter whilst the survivors die after
emergence from the second hibernation. Apion adults overwinter only
once. Both species hibernate with immature, or regressed gonads and
become active in March or April. Bruchidiw congregate around the
gorse flowers and feed on pollen; throughout this period they remain
immature and fly onto the broom bushes as soon as these are in flower.
Apion begins feeding in March, piercing the tender b m m stems and
leaves; they chew up the cells, imbibing only the juices. Both beetles
are restricted to broom and oviposit only in the presence of broom
pods. A laying Bruchidius extrudes droplets of a Iiquid which cements
the eggs to the surface of the pod. When broom hae finished flowering,
this beetle feeds on the pollen of Hokus lanatw L. and later on that of
Achillea millefolium L. Thus the decrewe of the adult population
throughout July and August is partly due to dispersal of adults to other
flowering plants.
Apion bores into the pod with its rostrum and deposits its eggs next
to the seeds. A fluid is secreted from the ovipositor which plugs the
oviposition hole.
Bruchidiw has four and Apion three larval instara within the aeeds.
Bruchidius pupates within the empty testa, but Apion moves out and
pupates within a “cement cell”. Adults emerge into the pod cavity and
are reIeased when the pod dehisces. BrwAidius adults disperse to overwintering sites and only a small proportion of the population may
return to the original breeding area next spring.
2. Hymenopteroua parasites of the immature 84age.4
of the seed beetles
Parnell (1964a) gives illustrated accounts of the immature stages of
seven hymenopterous parasites of the seed beetlea:
(a) Hubrocytw sequeeter (Walker) (Pteromalidae) paases its first generation on the larvae of A p h dkis (Forater) on gorse (Uka: eurqxwus).
N. WALOFF
A. S P E C I E S CONNECTED WITH T H E BROOM S E E D S
At Sitwood Park two beetles passed some, or all of their immature
stages within the broom weds; a small black BrwAidiw ate* (Marsham)
and a minute greyish weevil Apion fuscirostre Fabricius.
1. Bionomics of beetles
Both species overwinter in the adult stage. The hibernation sites of
Bruchidiua are widely scattered away from broom, those of Apion are
in the broom litter. Bruchidius is a long lived species and hibernates
two winters, but in contrast to the Chrysomelid, Phytodecta, on broom
(Waloff and Richards, 1958) it does not oviposit in the second season.
It was determined experimentally that a third of the adult population
of Bruchidius dies in the first winter whilst the survivors die after
emergence from the second hibernation. Apion adults overwinter only
once. Both species hibernate with immature, or regressed gonads and
become active in March or April. Bruchidiw congregate around the
gorse flowers and feed on pollen; throughout this period they remain
immature and fly onto the broom bushes as soon as these are in flower.
Apion begins feeding in March, piercing the tender b m m stems and
leaves; they chew up the cells, imbibing only the juices. Both beetles
are restricted to broom and oviposit only in the presence of broom
pods. A laying Bruchidius extrudes droplets of a Iiquid which cements
the eggs to the surface of the pod. When broom hae finished flowering,
this beetle feeds on the pollen of Hokus lanatw L. and later on that of
Achillea millefolium L. Thus the decrewe of the adult population
throughout July and August is partly due to dispersal of adults to other
flowering plants.
Apion bores into the pod with its rostrum and deposits its eggs next
to the seeds. A fluid is secreted from the ovipositor which plugs the
oviposition hole.
Bruchidiw has four and Apion three larval instara within the aeeds.
Bruchidius pupates within the empty testa, but Apion moves out and
pupates within a “cement cell”. Adults emerge into the pod cavity and
are reIeased when the pod dehisces. BrwAidius adults disperse to overwintering sites and only a small proportion of the population may
return to the original breeding area next spring.
2. Hymenopteroua parasites of the immature 84age.4
of the seed beetles
Parnell (1964a) gives illustrated accounts of the immature stages of
seven hymenopterous parasites of the seed beetlea:
(a) Hubrocytw sequeeter (Walker) (Pteromalidae) paases its first generation on the larvae of A p h dkis (Forater) on gorse (Uka: eurqxwus).