1. Department of Biological Sciences
Systematics of the snail-killing flies in the tribe Tetanocerini (Diptera: Sciomyzidae): Evolution of larval feeding strategies in the genus Tetanocera
Eric G. Chapman
Department of Biological Sciences
Kent State University
Ph. D. Prospectus

2. Sciomyzid Biology
• Larvae are predators, parasitoids, or saprophages of:
- Terrestrial Snails
- Semi-aquatic and aquatic non-operculate snails
- Operculate aquatic snails
- Semi-terrestrial succineid snails
- Slugs
- Snail eggs
- Fingernail clams
- Freshwater oligochaete worms
• Members of the family were grouped into 17 distinct feeding guilds by Knutson & Vala (2002).

3. Sciomyzid Relationships
Maximum Parsimony cladogram of generic-level relationships with 1000 bootstrap replicates (values greater than 50 shown). Data from Marinoni & Mathis (2000).

4. Tetanocera Biology
• All species are predators/parasitoids of snails as larvae
• Eggs are laid in the snails’ habitat
• Newly hatched larvae are “free living”
- Search for a suitable host snail
- Attach to the host and begin feeding
• Once the snail dies, the larvae continue feeding until all suitable tissue is gone
• Larvae then search for another host snail
• Pupation occurs either while floating or on land

5. Tetanocera Biology
• Species grouped into 6 feeding guilds by Knutson & Vala (2002) according to the type of prey and habitat
• Aquatic Pulmonate Snails
• Shoreline Pulmonate Aquatic Snails
• Succiniid Snails
• Slugs
• Terrestrial Snails
- Six feeding guilds is 2 more that any other
genus of Tetanocerini

6. Tetanocera plebeja

7. Tetanocera plumosa

9. Past Tetanocera Research
• 40 species worldwide have been described (29 North American species)
• Life cycles of about 2/3 of the N. American species have been discovered by Dr. Benjamin Foote.
• A morphological phylogenetic analysis of the N. Am. species done by Dr. Maryanne Shemory as part of her dissertation
- 29 taxa & 22 characters did not paint a clear picture of the evolutionary relationships between the species

10. Tetanocera Relationships
Strict consensus of 2 MP trees - bootstrap values > 50 shown
(1000 replicates).
Data from Shemory (1997)
re-analyzed using PAUP*

11. Materials & Methods • Genes sequenced thus far (all mitochondrial):
- COI (Cytochrome Oxidase I)…….1449 bp
- COII (Cytochrome Oxidase II)……731 bp
- 16s…………………………………428 bp
Total = 2608 bp
• Genes to be tried:
- 28s (nuclear)
- 12s (mitochondrial)
- Other nuclear markers…

12. Results
• The 16s, COI, & COII genes of 1-4 individuals of 12 Tetanocera species and 1 outgroup (Elgiva)
• A total of 19 specimens were sequenced
• Parsimony/bootstrap analysis shows that there is enough variability in these genes to be useful in phylogenetic analysis

13. Neighbor-Joining Dendogram

14. Bayesian Tree

16. Timeline for completion of project Specimens in hand for sequencing:
Atrichomelina 1 (1)
Coremacera 1 (9)
Dictya 2 (42)
Ectinocera 1 (1)
Elgiva 1 (7)
Euthycera 1 (18)
Hydromyia 1 (1)
Illione 1 (8)
Pherbina 1 (4)
Pherbellia 1 (92)
Poecilographa 1 (1)
Pteromicra 1 (18)
Renocera 3 (7)?
Sciomyza 1 (5)
Sepodon 3 (72)
Tetanocera (40)
Tripetoptera 1 (2)

17. Timeline for completion of project
• Collecting trips:
- Summer 2003: collect across Canada
-Goal: get remainder of N. Am. Tetanocera
- Winter :
- Trip to Argentina & Chile
- June 2004: Trip to Mexico & Guatemala
-Goal: get members of the 15 sciomyzid genera endemic to the Neotropics

18. Materials & Methods • Fresh specimens preserved in 100% EtOH
• Thorax removed and total DNA isolated using Qiagen DNeasy Animal Tissue Kit
• 16s Ribosomal gene fragment (550 bp) amplified using 16Sar-L and 16Sbr-H primers
• CO1 Ribosomal gene fragment (650 bp) amplified using LCO 22-me and
HCO 700-dy primers

19. Materials & Methods
• Amplified DNA purified electrophoretically overnight in a 1.5% NuSeive gel, and cleaned with the Wizard Gel Extraction kit
• Sequencing reactions on purified 16s & CO1 DNA (both light & heavy strands) done with Amplicycle sequencing kit
• DNA sequenced on a LiCor 4200S-2 gel scanner using KBplus 5.5% acrylamide gel
• Bases called using LiCor Base ImagIR image analysis program

20. Materials & Methods
• Light & heavy strand reads aligned using GeneJockeyII and discrepancies were cleared up by examining the gel images
• 16s & CO1 sequences of all available taxa were aligned with GeneJockeyII (saved as text)
• Text file converted to “nexus” file using Microsoft Word
• Data matrix (nexus file) “cleaned up” using MacClade
• Trees generated with PAUP* for Parsimony & Neighbor-Joining analysis, and with Mr. Bayes for Bayesian analysis