File:
<aphidiid.htm> [For educational purposes
only] Glossary
<Principal Natural Enemy Groups> <Citations> <Home> |
COLEOPTERA, Anthribidae. -- <Images> & <Juveniles> Description & Statistics Clausen (1940) noted that neither of the above
researchers observed actual oviposition, although Yano assumed that the eggs
were placed on or in the vicinity of the host scales and that the young
larvae later penetrated the egg chamber.
Silvestri believed that they were laid beneath the margin of the scale
and into the chamber by means of the extensible ovipositor. Clausen (1940) observed oviposition of B. niveovariegatus
in both field and laboratory, in E.
pela and several species of Kermes.
The feeding habit of the female was found to have an intimate
relationship with oviposition. The
female breaks the hardened integument of the host scale and feeds on the body
contents, after which she reverses her position, thrusts the ovipositor into
the wound and through the thin ventral body wall, and places her egg within
the egg chamber. The beetle egg is
usually found adhering to the body wall of the host at the point of
penetration of the beetle's ovipositor.
The feeding wound is quite large, but it often heals over and normal
oviposition by the scale is possible, though a large number die from their
injuries. Young beetle larvae feed only on the eggs. Later, after the host female dies, they
feed extensively on body tissues also.
When hosts are killed by injury associated with feeding of the female
beetle, the larva may develop largely as a scavenger rather than an egg
predator. Only a single B.
niveovariegatus develops in a
host, even though the latter may be quite large and have sufficient eggs to
bring several beetles to maturity.
Therefore, the degree of control exercised is not as high as the
50-70% of scales attacked wound indicate (Clausen 1940/1962). In B.
niveovariegatus and B. fasciatus,
there is thought to be only a single annual generation, at least on the above
single-brooded hosts. Adults emerge
late in June, persist in that stage through winter and appear for oviposition
the following April-May. This is a small family of “fungus weevils” that
is unique by having a broad beak. The
larvae of some species reside in
woody fungi while others occur in corn and wheat smut, and some in
dead wood. Adults are found under old
bark or on dead twigs (Headstrom
1977, White 1983). Some members of the genus Brachytarsus (= Anthribus) have been reared from
lecaniine Coccidae. Yano (1915) first
reported on the predaceous behavior and life history of B. niveovariegatus
Roel. attacking the Chinese wax scale, Ericerus
pela Chev. in Japan. During May-June ca. 50% of female scales
contained mature Brachytarsus
larvae, pupae or adults in the egg chamber.
Adults emerged during late June, and the remains of host scales were
conspicuous because of the large, circular emergence holes on the dorsum. Silvestri (1919b) found B. fasciatus
Foerst. common as a natural enemy of Eulecanium
coryli in south Europe, where a
maximum parasitization of 50% of scales occurred. Oviposition is mainly in April when a considerable number of
eggs are present beneath host scales and the beetle egg is apparently laid among
them. Female beetles feed on the body
fluids of the host scales and also on the eggs. The larvae are confined to the cavity underneath the individual
host scale and are dependent on the eggs found there for food. Therefore, the relationship is identical
with that of the chalcidoid Scutellista
cyanea Motsch. and its host Saissetia oleae Bern. The
larva is weevil-like and robust, with the legs being represented by small
conical protuberances. The cycle from
egg to adult is around 2 months.
Adults appear in June and persist without oviposition until hosts of
the proper stage become available the following spring. Brachytarsus
nebulosus Foerst. is also a
natural enemy of several other species of lecaniine Coccidae in Europe (Prell
1925). Anthribidae
Billberg, 1820 [placed on the Official List of Family-Group Names in Zoology
by ICZN (1994: 72), with the endorsement that it and other family-group names
based on Anthribus Geoffroy,
1762 are to be given precedence over those based on Choragus Kirby, 1819] [source: ICZN
(1994: 72)] Type
genus: Anthribus Geoffroy, 1762
[source: ICZN (1994: 72)] [stem = Anthrib-]
Synonyms
Choragidae Kirby, 1819 [placed on the Official List of Family-Group
Names in Zoology by ICZN (1994: 72), with the endorsement that it and other
family-group names based on Choragus
Kirby, 1819 are not to be given priority over those based on Anthribus Geoffroy, 1762] [source: ICZN
(1994: 72)] [subfamily] Type genus: Choragus
Kirby, 1819 [source: ICZN (1994: 72)] [stem = Chorag-] References:
Please refer to <biology.ref.htm>,
[Additional references may
be found at: MELVYL Library ] Headstrom,
R. 1977. The Beetles of America.
A. S. Barnes & Co. London & NY. 488 p. White,
R. E. 1983. A Field Guide to the Beetles of North America. Houghton Mifflin Co., Boston. 368 p. |