104
N. WALOFF
develop when the midge oviposits in very young pods, but by far the
most common galls were in the form of oval swellings at the bases of
otherwise normal pods with developing seeds. These are formed when
the midge oviposits in an already elongated pod.
Only one egg is laid and a single large orange larva feeds on the
fungal myoelium that covers the inner walls of the gall.
Groups of 6-8 eggs and larvae of Trotteria sarothamni are found in
the pod galls in June. This species is an inquiline, not a strict parasite.
The ovipositing [Protteria does not paralyse Asphondylia larvae, but the
survival of the latter depends on the stage it has reached when Trdteria
larvae hatch. If they hatch before an Asphondylia larva is fully grown
it dies, probably because the movement of the active Trdteria larvae
prevents it from feeding and pupating. However, if Asphondylia is in
the prepupal or pupal stage when Trotteria hatch the inquiline larvae
are cramped and their development is delayed until the Asphondylia
adult has emerged. The number of galls with living Trotteria and
Asphondylia was much smaller than that with dead Asphondylia.
Trotteria larvae feed on the white fungal mycelium within the gall and
this may explain why the species is inquiline. Yarnell (1964b) suggests
that probably Asphondylia has some means of transferring fungal spores
whilst ovipositing, while Trotteria is unable to do so.
No Trotteria larvae wexe ever seen in the bud galls, and most of those
within the pod galls emerged as adults in June of the following year.
2. The parasitic species in the gat%
(a) Aprostocetus brevicopnis Panzer (Eulophidae). From June 1960
and 1961 pod galls were found with 8-10 eggs of Aprostocetus. The
ovipositing period of this species is so long that new adults were
emerging while the parent generation was still laying and superparasitism often occurred when the Eulophids paralysed and oviposited
on larvae of their own species. Normally the female paralyses and oviposits on Aspho&ylia larva, laying eggs on the body of the host. When
more than 10 Aprostocetus larvae inhabited a pod, 2 or 3 of them died
as a result of overcrowding. The active larvae devour the host tissue
and then become phytophagous, feeding both on the fungal mycelium
and the gall tissue. Females emerging from pod galls live for 9 to 10
months and oviposit in the bud galls in the following April. Adults from
bud galls are shorter lived and oviposit in the pod galls. Thus the life
history of this parasite is attuned to that of its host.
When Aprostocetus oviposited in galls with Trotteria they usually
paralysed only one or two larvae. The parasite larvae fed only on the
paralysed larvae or became phytophagous immediately. There waa no
evidence that the Apostocetua larvae either killed or fed on the non-
N. WALOFF
develop when the midge oviposits in very young pods, but by far the
most common galls were in the form of oval swellings at the bases of
otherwise normal pods with developing seeds. These are formed when
the midge oviposits in an already elongated pod.
Only one egg is laid and a single large orange larva feeds on the
fungal myoelium that covers the inner walls of the gall.
Groups of 6-8 eggs and larvae of Trotteria sarothamni are found in
the pod galls in June. This species is an inquiline, not a strict parasite.
The ovipositing [Protteria does not paralyse Asphondylia larvae, but the
survival of the latter depends on the stage it has reached when Trdteria
larvae hatch. If they hatch before an Asphondylia larva is fully grown
it dies, probably because the movement of the active Trdteria larvae
prevents it from feeding and pupating. However, if Asphondylia is in
the prepupal or pupal stage when Trotteria hatch the inquiline larvae
are cramped and their development is delayed until the Asphondylia
adult has emerged. The number of galls with living Trotteria and
Asphondylia was much smaller than that with dead Asphondylia.
Trotteria larvae feed on the white fungal mycelium within the gall and
this may explain why the species is inquiline. Yarnell (1964b) suggests
that probably Asphondylia has some means of transferring fungal spores
whilst ovipositing, while Trotteria is unable to do so.
No Trotteria larvae wexe ever seen in the bud galls, and most of those
within the pod galls emerged as adults in June of the following year.
2. The parasitic species in the gat%
(a) Aprostocetus brevicopnis Panzer (Eulophidae). From June 1960
and 1961 pod galls were found with 8-10 eggs of Aprostocetus. The
ovipositing period of this species is so long that new adults were
emerging while the parent generation was still laying and superparasitism often occurred when the Eulophids paralysed and oviposited
on larvae of their own species. Normally the female paralyses and oviposits on Aspho&ylia larva, laying eggs on the body of the host. When
more than 10 Aprostocetus larvae inhabited a pod, 2 or 3 of them died
as a result of overcrowding. The active larvae devour the host tissue
and then become phytophagous, feeding both on the fungal mycelium
and the gall tissue. Females emerging from pod galls live for 9 to 10
months and oviposit in the bud galls in the following April. Adults from
bud galls are shorter lived and oviposit in the pod galls. Thus the life
history of this parasite is attuned to that of its host.
When Aprostocetus oviposited in galls with Trotteria they usually
paralysed only one or two larvae. The parasite larvae fed only on the
paralysed larvae or became phytophagous immediately. There waa no
evidence that the Apostocetua larvae either killed or fed on the non-