Establishing the higher
groupings. The PEET proposal stated that a higher level
phylogeny for the family Therevidae was needed so that small,
monophyletic groupings of taxa could be monographed. The strategy
for establishing a higher level classification of the Therevidae
entailed two aspects. The first was a strong cladistic analysis
based on morphological evidence, which would develop hypotheses
of monophyletic units. This was to be followed by a molecular
cladistic study to test those hypotheses. We felt that this would
provide the most rigorous test of monophyletic units in the Therevidae.
Morphological progress.
PI Irwin continues to work with Co-PI Yeates on developing a
morphologically based higher classification of the Therevidae.
Characters on the female terminalia and head have already been
found and their states defined and polarized. Irwin is currently
searching for characters on the thorax, wing, legs, abdomen,
and male terminalia. These characters are being polarized and
scored for all 50 plus genera and five outgroups currently under
study. Preliminary trees based on parsimony and maximum-likelihood
approaches will be generated using Hennig 86 and PAUP and examined
using MacClade. The shortest resulting cladogram(s) will form
hypotheses to be tested by molecular studies.
Mr.
Gaimari and Dr. Irwin have delimited a new tribe of Therevinae,
with a New World-Asian distribution. This tribe includes Ozodiceromyia,
Cyclotelus, Breviperna, Procyclotelus, Ammothereva, and
5 new genera. All genera have been fully reviewed and diagnosed,
and new synonymies and combinations have been established. Additional
morphological information has been provided for all genera,
and are included in a key. A monograph on the tribe is ready
for submission for publication.
Molecular progress.
Brian Wiegmann and Longlong Yang have completed amplification
and sequencing of 1.3 kb of the 28S rRNA and 1 kb of Elongation
Factor- 1a genes in 40 species representing 30 genera of Therevidae
and outgroups. These data were obtained by direct PCR for 28S
and RT-PCR for EF1a, followed by automated DNA sequencing on
an ABI 377 autosequencer. Sequence electropherograms were edited
and base calls checked by inspection in the program GAP4 of
the STADEN package. Sequences were aligned in GDE 2.2. Phylogenetic
analyses were carried out in PAUP* 4 test versions (D. Swofford
pers. comm.). The following questions are being addressed in
phylogenetic analyses of these data:
Does the 28S ribosomal RNA gene contain enough phylogenetically
informative variation to reliably reconstruct higher-level
relationships in the Therevidae?
Is the family Therevidae a monophyletic group?
What is the sister-group of Therevidae? Do molecular
data support morphological evidence implicating the Scenopinidae
as the closest relative of the Therevidae?
What is the phylogenetic status of the genera Apsilocephala
and Clesthentia?
What are the major groupings of Therevidae below the
family level? Do the molecular data support the current morphological
classification?
Current
results of molecular phylogenetic analyses: High bootstrap values
(>60%) support the monophyly of the Therevidae (excluding
Apsilocephala) and monophyly of Therevinae. The monophyly
Phycinae + Ruepellia-group is supported by parsimony
analysis, but bootstrap values for this clade are low. Our results
differ from the preliminary 5-subfamily classification except
that the Therevidae is divided into two major groups, Phycinae
and Therevinae that may represent two reasonable subfamilies.
The controversial genus, Apsilocephala, is placed outside
the Therevidae within the Scenopinidae.
Within
subfamilies, the monophyly of Therevinae is highly supported
by higher bootstrap value (>90%). However, the relationships
among Agapophytus-group genera are not well resolved
by the data from 28S rRNA gene. The Agapophytus-group
is paraphyletic on our trees and branch lengths for individual
clades within it are short, indicating that 28S rRNA gene alone
may not provide sufficient phylogenetic information to recover
relationships below the subfamily level. Additional molecular
data will be required to gain strong support for relationships
at lower level in the family and within subfamilies and to place
controversial genera such as Apsilocephala.
Elongation
factor -1alpha (EF-1a) has been sequenced for most of these
same taxa. This gene shows higher variability within therevid
subgroups, suggesting that it is a suitable candidate for lower
level phylogenetic analysis within the Therevidae. Phylogenetic
analysis of 908 aligned bp of EF-1a for 17 taxa is concordant
with results found for 28S rDNA. Like 28S, EF-1a supports the
monophyly of the Therevidae excluding Apsilocephala,
the monophyly of the Phycinae + Ruepellia-group clade,
and the Therevinae.
Nucleotide
sequence data have also been collected for 28S rDNA and phosphoenolpyruvate
carboxykinase to examine the position of the Therevidae within
the Asiloidea and resolve relationships between lower brachyceran
subgroups. Sequencing of 28S rDNA for 85 brachyceran taxa has
been completed.
A
review of higher-level phylogenetic evidence and research on
Diptera was completed for the serial Annual Review of Entomology
by PI's Yeates and Wiegmann. This paper summarizes recent support
for dipteran phylogeny from morphological and molecular studies
covering the past 20-25 years. The manuscript was completed
while PI Yeates was on sabbatical to the laboratory of PI Wiegmann
at NCSU.
Genus level revisions.
Status of Agapophytus. This large speciose
genus is being monographed by Mr. Shaun Winterton. Original
descriptions and revisions of the 13 valid species have been
compiled. Type material for most of these species has been borrowed,
and arrangements are being made to visit collections holding
types unavailable for loan. Most specimens required for this
study are on loan with a large collection of approximately 70
to 100 undescribed species accumulated and sorted awaiting description.
All specimens for study have been entered into the database
by the Irwin lab and labeled with loan information and unique
specimen numbers. Most of the specimens required for molecular
studies have been collected and are presently stored at the
University of Queensland.
Status of Anabarhynchus. The monograph,
by Dr. Lyneborg, PI Irwin, and Co-PI Yeates, for this speciose
Australian genus is nearly finished. The three met in Copenhagen
in 1996 to work on the manuscript. Species descriptions have
been completed and PMTs of over 100 illustrations by Jill Mullett
were sent to Denmark in Fall 1997.
Status of Brachylinga. Mr. Metz has gathered
specimens for a monographic treatment of the genus Brachylinga
from the world collections. Mr. Metz is now sorting specimens
to species from his previously delimited sorting groups mainly
using dissected male genitalia. Four holotypes of Brachylinga
species are currently on hand. Most remaining holotypes will
have to be examined in European museums.
Status of Cylotelus. This genus is being
treated by Mr. Gaimari and Dr. Irwin, as part of ongoing studies
of the newly erected tribe, Cyclotelini including Ozodiceromyia.
All of the specimens of Cyclotelus on hand have been
entered into the database system, and preliminary sorting has
yielded 26 species in the South and Central American fauna,
and at least 3 species endemic to Greater Antillean islands.
The North American fauna has yet to be sorted fully, but numerous
species have been recognized, and working concepts for species-groups
are being refined.
Status of Lindneria. Starting September
1997, Mr. Metz and Dr. Irwin initiated a treatment of the small
Neotropical genus Lindneria. Represented by few specimens
in collections, this genus is currently monotypic, but will
include an additional species moved from the genus Psilocephala.
Both holotype specimens for the monographic treatment are on
loan. Illustrations of included taxa are underway. Recent study
of a fossil specimen from Dominican amber of Oligo-Miocene age
has suggested that it is not contained within the Lindneria
genus concept, but may be the sister genus. The fossil specimen
will be described as the type of a new genus.
Status of Ozodiceromyia. This large
genus is under study by Mr. Gaimari. Approximately 30,000 specimens
have been sorted into 112 species. All specimens have been input
into the MANDALA database system. After studying all the types
of the known species, names have been associated with their
proper species, and synonymies and new combinations have been
established. Of the 36 names from Irwin and Lyneborg (1981),
27 are valid, including new combinations. The known species
have been fully analyzed using parsimony to provide a phylogenetic
framework for the remaining species. The additional 85 species
are currently being described and placed within this phylogenetic
context. In addition, the genus is placed in a phylogenetic
context within a new tribe including 10 genera. This new tribe
has been fully treated phylogenetically, and biogeographical
analyses have yielded an interesting account of their New World
and Asian distribution.
Status of Pandivirilia. This genus contains
17 species from the Nearctic and Palaearctic regions that had
previously been placed in the genera Dichoglena, Pandavirilia,
and Viriliricta. Three species are new to science. The
species were revised by Don Webb and Mike Irwin, a phylogeny
is hypothesized, and keys to the species are provided. This
revision is currently undergoing in-house review.
Status of Tabuda and Tabudamima with
the description of a new genus. The genus Tabuda,
which contains two Nearctic species and four Palaearctic species
(two of which are new to science), has been revised. The species
Tabuda borealis was determined to be phylogenetically
distinct from Tabuda and has been placed in a new genus.
The genus Tabudamima, which contains one Nearctic species
was included in this revision for the purpose of generic comparison.
The species were revised by Don Webb (collaborator) and Mike
Irwin, a phylogeny is hypothesized, and keys to the genera and
species are provided. This revision is currently undergoing
in-house review.
Status of Thereva and Acrosathe.
These two genera, both found in the Nearctic and Palearctic
regions, are being revised by Mr. Holston. Thereva includes
over 200 currently valid species, and over 200 additional species
names are relevant to the nomenclature of this genus. By comparison,
Acrosathe includes only 14 valid species names with nine
additional species names relevant to the nomenclature of Acrosathe.
With the guidance of F. C. Thompson, Mr. Holston has compiled
these species names into a systematic database, which will be
completed by Fall 1998. Name records from this database are
being incorporated into the therevid database, MANDALA, names.fp3
file. Concurrently, Mr. Holston will compose a historical review
of the family Therevidae with an emphasis on the type genus,
Thereva. This nomenclatural work will constitute the
majority of his Master's thesis, which will be completed by
Fall 1998. Mr. Holston has examined the available specimens
of Nearctic Thereva from museum collections and has begun
morphological study on Thereva material from other biotic
regions, received primarily from European museums.
Status of [new Australian genus A]. This genus
of endemic Australian therevids was monographed by Mr. Shaun
Winterton and is presently in press with Invertebrate Taxonomy
(CSIRO publications). Of the twenty species in this genus 19
are new to science. The genus has been placed in the Taenogera-Group
of genera.
Additional Research.
Relationships of male & female genitalia.
Mr. Metz continues to analyze the relationship of male and female
Ozodiceromyia nanella (Cole) genitalia. He has two years
of data on a population from a site in New Mexico and has written
two small proposals to continue this work in 1998.
Parasitic mites on Diptera. Mr. Metz has also
initiated the study from the same site in New Mexico of the
association of the families of Diptera with parasitic mites.
Long-term Malaise trapping
survey. Honours student, Narelle Power is conducting
a long-term malaise trapping survey near Brisbane, Australia
using 6 m Focks Malaise traps. Three traps are stationed in
each of three habitats: coastal dunes (alt 5m), sclerophyll
forest (200 m) and upland rainforest (ca. 600 m). They have
been monitored since the beginning of August 1997. As of 20
March 1998, 1100 specimens of 47 species of therevids have been
collected in 17 genera
Genera are as follows:
Agapophytus .......................(4 species)
Bonjeania .........................(1 species)
Squamopygia (Pipinnipons)..........(2 species)
Acraspisa..........................(1 species)
Anabarhynchus.............(at least 7 species)
Johnmannia.........................(1 species)
Taenogera..........................(2 species)
Ectinorhynchus............(approx. 12 species)
Acatopygia.........................(2 species)
Acupalpa ...........................(4 species)
Australian genus A.................(3 species)
Australian genus B.................(2 species)
Australian genus C.................(1 species)
Australian genus D.................(1 species)
Australian genus E.................(1 species)
Undescribed genus..................(1 species)
Parapsilocephala...................(2 species)
Standardized terminology. As part of his Ph.D.,
and in collaboration with Mr. Stephen Gaimari and Co-PI's David
Yeates and Michael Irwin, Mr. Shaun Winterton has proposed a
standardized terminology for body vestiture and male genitalia.
The former developed using scanning electron microscopy facilities
at the University of Queensland. This terminology will be adopted
in all monographs produced by the therevid group.
Homology of musculature and sclerotized portions of
male genitalia. Co-PI Yeates has collaborated with Dr. Olga
Ovtchinichova (Zoological Institute, St. Petersburg) in a study
of the homology of musculature and sclerotized portions of the
male genitalia of Therevidae. This has resulted in a manuscript
in press in The Australian Journal of Entomology.
Morphology & histology of a novel structure in
the female therevid reproductive system. In collaboration
with Dr. David Merritt and Anthony O'Toole (University of Queensland),
Mr. Shaun Winterton, Co-PI David Yeates and PI Michael Irwin
have made detailed studies into the morphology and histology
of a novel structure in the female therevid reproductive system.
The studies include histological sections of virgin and mated
females to determine the possible function of this structure.
Photographic library of live therevids. In collaboration
with Mr. Anthony O'Toole (University of Queensland), Mr. Shaun
Winterton and Co-PI David Yeates have begun to accumulate a
photographic library of live therevids collected from the field.
One of these photographs (of an undescribed genus and species)
recently won first prize in the photographic competition at
the 1997 annual general meeting of the Australian Entomological
Society in September.
Publications:
Yeates,
D. K., and M. E. Irwin. 1996. Cladistic reappraisal and biogeography
of the Apioceridae (Diptera: Asiloidea). Zoological Journal
of the Linnaean Society. 116:247-301.
Irwin,
M. E. 1997. Therevidae. In: Solís, A. (ed.), Las Familias
de insectos de Costa Rica. INBio. <http://www.inbio.ac.cr/papers/insectoscr/Texto438.html>
Irwin,
M. E., and G. E. Kampmeier. 1997. PEET: A training effort that
is paying dividends. Illinois Natural History Survey Reports
347: 2. (September/October) <http://www.inhs.uiuc.edu/chf/pub/surveyreports/sep-oct97/peet.html>
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