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projects->Braconidae->
Overview and Objectives:
The superfamily Ichneumonoidea contains the two largest families
within the Hymenoptera: the Ichneumonidae and the Braconidae.
There are approximately 15,000 valid species of Braconidae
worldwide. Though subfamily classification is somewhat
controversial, there is general agreement on an opiine + alysiine
clade that represents about 17% of the valid species within the
family. The clade is defined largely on biological features
(koinobiont endoparasitism of cyclorrhaphous Diptera, with
emergence from the host puparium). As several authors have
already observed, recognition of Alysiinae renders Opiinae
paraphyletic since the Alysiinae have traditionally been defined
by the possession of exodont mandibles. Other Braconidae
(including Opiinae) lack this feature. The discovery in recent
years of several exodont specimens that cannot be readily
accomodated within the Alysiinae has created additional problems
for defining either of these two taxa as monophyletic.
A basic impediment to monographic research on the Opiinae is the
paucity of rigorously defined monophyletic groups, a problem that
extends through all levels of the classification. Relatively few
tribal and subtribal taxa have been proposed, and the vast
majority of the opiine species have traditionally been placed in Opius
Wesmael. Opius s. l. is an assemblage of 1000+ species that share
no uniquely derived feature. Opius is further divided
into 50 subgenera, with the vast majority of these defined by
different combinations of the same relatively small set of
characters.
Our monographic work began with selection of several taxa defined in part by distinctive body sculpture (e. g. Euopius Fischer, Tolbia Cameron, Gastrosema Fischer, including one putative basal group (Ademon Haliday). It has expanded to include other genera (primarily Fopius Wharton)
and an assessment of generic relationships among the 65 valid genera of Alysiini
(to facilitate choice of outgroups for studies on phylogeny of Opiinae).
Additionally, Fredrik Ronquist, a PEET collaborator from Sweden who provided
expertise for cynipoid trainee Matt Buffington, has now (2002) recruited
a Ph. D. student to work on Opiinae. His proposed work on Biosteres s. s., directed in part by Wharton as part of a PEET-like program in Sweden, will complement the work here.
Peripheral work on the family Braconidae includes two publications on
nomeclature and classification of the family as a whole (Wharton 2000, Wharton
and van Achterberg 2000). These explore the problems of stability of
higher ranks and how ranks are used in modern classifications. Clarification
of authorship and date of publication of the names Alysiinae and Opiinae
led to a publication on the 224 family group names that have been used in
Braconidae, providing an assessment of their availability and establishing
priority of several competing names. Two other publications are based
on the work of students who received training for a brief period with our
PEET program. Hugo Delfin examined the Mexican fauna of Rogadinae,
one of the putative outgroups of the Alysiinae + Opiinae clade. Hugo
worked in our laboratory for several weeks, providing cross-training opportunities
for PEET students Buffington and Kula to deal with problems of nomenclature
and character coding prior to the development of their own data sets.
Imelda Mercado initiated a PEET monograph on the genus Ademon before leaving the program to seek a degree in food microbiology. While working on Ademon, she
finalized for publication her Masters degree work on the Mexican Cardiochilinae
(another group of Braconidae). Cardiochilines contain symbiotic polydnaviruses
in the female reproductive tract. Polydnaviruses are well-characterized
relative to more recently discovered viruses we found in the reproductive
tracts of certain opiines, and thus are a logical basis for comparison.
Finally, we have been exploring the basal relationships of the Apocrita as
part of an effort to bring all 4 components of our PEET project together.
One presentation on this work has been made at the annual meeting of the
International Society of Hymentopterists.
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