Conflict from Cell to Colony

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(No Transcript)
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My research
Current research Caste conflict in social
insects (stingless bees termites)
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Sex allocation
queen50 females
PARENT-OFFSPRING CONFLICT
workers75 females
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Wolbachia

• Maternally transmitted symbiont that manipulates
  host to produce female biased broods
• Cytoplasmic sex ratio distorter
• Alpha-proteobacterium
• Occurs mainly in arthropods (insectsCrustacea)
  nematodes

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Effects on host reproduction

• Male Killing
• Feminisation
• Parthenogenesis Induction

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Cytoplasmic incompatibility
Inviable

-

• Reduces fitness of Uninfected Female x Infected
  Male Crosses
• Gives an advantage to infected females
• Sterility in diploids, but production of males
  only in haplo-diploids

NormalOffspringProduction
-

-
-
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Phylogeny
Other alpha proteobacteria
Gamma proteobacteria
Wolbachia
0.1
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Aims

• Does Wolbachia occur in ant societies and if so
  in what frequency?
• What effects does it have?Three case studies
• Parthenogenetic species
• Wood ant Formica truncorum
• Leptothorax nylanderi
• Host-parasite coevolution?

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Methodology PCR Assay

• Polymerase Chain Reaction using Specific Primers
• Targets ftsZ and wsp Wolbachia genes
• Positive, negative and nuclear DNA (18S rDNA)
  controls
• Negative samples retested twice

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Methodology PCR Assay
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High Incidence Worldwide
3451 samples
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Morphological evidence

• Present in trophocytes and oocytes
• Electron and light microscopical (DAPI) evidence

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Aims

• Does Wolbachia occur in ant societies and if so
  in what frequency? YES, IN HIGH FREQUENCY
• What effects does it have?Three case studies
• Parthenogenetic species
• Wood ant Formica truncorum
• Leptothorax nylanderi
• Host-parasite coevolution?

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Aims

• Does Wolbachia occur in ant societies and if so
  in what frequency? YES, IN HIGH FREQUENCY
• What effects does it have?Three case studies
• Parthenogenetic species
• Wood ant Formica truncorum
• Leptothorax nylanderi
• Host-parasite coevolution?

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Parthenogenesis induction?
6 Parthenogenetic Ants Cape honeybee Cataglyphi
s cursor Apis mellifera capensisCataglyphis
piliscapa Pristomyrmex pungens Cerapachys
biroi Messor capitatus Platythyrea punctata 250
samples, avg. 6 cols./species
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Wolbachia in F. truncorum
With Lotta Sundström University of Helsinki
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Formica truncorum

• Extensive variation in sex-ratio produced by
  different colonies
• Linked to facultative sex-ratio biasing
• Workers kill brothers in colonies headed by
  singly mated queen
• But not in colonies with double mated queen
• Does Wolbachia affect the sex-ratio too?

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Predictions

• Effect on the sex-ratio
• Males should be infected less than queens
• Sex-ratio should be correlated with infection
  rates
• Incompatibility
• Males and queens should be infected equally
• Uninfected colonies should not be able to survive

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Formica truncorum

• Males (96) and queens (94) infected equally
• All colonies infected (total 33) despite
  production of 6 uninfected queens by each colony
• Consistent with an incompatibility effect
  Uninfected queens do not survive past the
  founding stage due to incompatible matings

Wenseleers, Sundström Billen (2002) Proceedings
of the Royal Society of London B, in press
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Infection and sex-ratio
Wenseleers, Sundström Billen (2002) Proceedings
of the Royal Society of London B, in press
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Infection and colony fitness
Wenseleers, Sundström Billen (2002) Proceedings
of the Royal Society of London B, in press
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Infection rates
plt0.015
plt0.0001
N296
N158
N387
Wenseleers, Sundström Billen (2002) Proceedings
of the Royal Society of London B, 269 623-629
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Clearance in lab experiments
p lt 0.0001
After 2 month exposure to 20C
Worker pupae
N89
N90
7 colonies
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Conclusions

• No effects on the sex-ratio
• Probably causes incompatible matings
• Deleterious effects on colony function, but
  partly mitigated by clearance of infection in
  adult workers

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Leptothorax nylanderi

• Test experimentally whether Wolbachia causes
  incompatible matings
• Setup antibiotic treatment as an artificial
  means of creating the uninfected queen x infected
  male crossing type
• Prediction male production (infertility)
  following antibiotic treatment

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Antibiotics experiments
4 coloniesN70
7 coloniesN152
?2 10.51, p lt 0.001
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Aims

• Does Wolbachia occur in ant societies and if so
  in what frequency? YES, IN HIGH FREQUENCY
• What effects does it have?Three case studies
• Parthenogenetic species
• Wood ant Formica truncorum
• Leptothorax nylanderi
• Host-parasite coevolution?

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Methodology Sequencing
28 sequencesAligned with previously sequenced
relatives

• Wolbachia surface protein wsp was sequenced
  (approx. 550 bp)
• Direct cycle sequencing when ants were infected
  by single strain
• Cloning and sequencing when ants were infected by
  multiple strains (TA-cloning kit, pUC57 vector)

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High strain diversity
Solenopsis invicta (imported)
Coleomegilla maculata lengi
Doronomyrmex pacis A1
Myrmica sulcinodis (Pyrenees)
Plutella xylostella
Laodelphax striatellus
Diaphorina citri
Porcellionides pruinosus
Acraea encedon 1
Trichopria Tsp2
Myrmica rubra
Acromyrmex insinuator A
Formica lemani
Plagiolepis pygmaea
Sphaeroma rugicauda
Dryinid wasp sp
Trichogramma kaykai (LC110)
Bactocera cucurbitae
Muscidifurax uniraptor
Trichogramma bourarachae
Tribolium madens
Tribolium confusum
Rhinophoridae unid
Leptopilina heterotoma 2
Doronomyrmex kutteri B
Glossina morsitans centralis
Doronomyrmex pacis B2
Trichogramma spp.
Coleomegilla maculata
Adalia bipunctata B
Drosophila bifasciata
Nasonia vitripennis A
Aedes albopictus (Houston)
Drosophila simulans (Coffs Harbour)
Adalia bipunctata A
A
B
Acromyrmex octospinosus B3
Drosophila melanogaster (Cairns)
Drosophila melanogaster (CantonS)
Acromyrmex insinuator B1
Acromyrmex echinatior B
Drosophila simulans (Riverside)
Solenopsis invicta (native)
Acromyrmex echinatior A1
Acromyrmex octospinosus B1
Solenopsis richteri A
Acromyrmex octospinosus B2
Doronomyrmex pacis A2
Acromyrmex insinuator B2
Myrmica sabuleti
Solenopsis invicta A (native)
Telenomus nawai
Acromyrmex octospinosus A1
Encarsia formosa
Diplolepis rosae
Doronomyrmex goesswaldi A1
Leptopilina australis
Cadra cautella
Phlebotomus papatasi (Israel)
Gnamptogenys menadensis
Tetranychus urticae
Doronomyrmex pacis A3
Cadra cautella 2
Acraea encedon
Glossina austeni
Asobara tabida
Culex quinquefasciatus
Asobara tabida 3
Drosophila sechellia
Drosophila simulans (Hawaii)
Cataglyphis iberica
Culex pipiens (ESPRO)
Trichopria drosophilae
Isopods
Formica rufa
Teleutomyrmex schneideri
Bactocera sp 1 AscD
Aedes albopictus (Houston)
Myrmica sulcinodis (Russia)
Formica fusca (KH B)
Formica pratensis
Drosophila simulans (Watsonville)
Myrmica sulcinodis (Samso D)
Dacus destillatoria
Leptothorax acervorum
Formica fusca (SJW B)
Formica fusca (Mols D)
Formica truncorum
Doronomyrmex kutteri A
Doronomyrmex pacis A4
Formica polyctena
Neochrysocharis formosa
Doronomyrmex pacis B1
Doronomyrmex goesswaldi A2
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No match with host phylogeny
Solenopsis invicta (imported)
Coleomegilla maculata lengi
Doronomyrmex pacis A1
Myrmica sulcinodis (Pyrenees)
Plutella xylostella
Laodelphax striatellus
Diaphorina citri
Porcellionides pruinosus
Acraea encedon 1
Trichopria Tsp2
Myrmica rubra
Acromyrmex insinuator A
Formica lemani
Plagiolepis pygmaea
Sphaeroma rugicauda
Dryinid wasp sp
Trichogramma kaykai (LC110)
Bactocera cucurbitae
Muscidifurax uniraptor
Trichogramma bourarachae
Tribolium madens
Tribolium confusum
Rhinophoridae unid
Leptopilina heterotoma 2
Doronomyrmex kutteri B
Glossina morsitans centralis
Doronomyrmex pacis B2
Trichogramma spp.
Coleomegilla maculata
Adalia bipunctata B
Drosophila bifasciata
Nasonia vitripennis A
Aedes albopictus (Houston)
Drosophila simulans (Coffs Harbour)
Adalia bipunctata A
A
B
Acromyrmex octospinosus B3
Drosophila melanogaster (Cairns)
Drosophila melanogaster (CantonS)
Acromyrmex insinuator B1
Acromyrmex echinatior B
Drosophila simulans (Riverside)
Solenopsis invicta (native)
Acromyrmex echinatior A1
Acromyrmex octospinosus B1
Solenopsis richteri A
Acromyrmex octospinosus B2
Doronomyrmex pacis A2
Acromyrmex insinuator B2
Myrmica sabuleti
Solenopsis invicta A (native)
Telenomus nawai
Acromyrmex octospinosus A1
Encarsia formosa
Diplolepis rosae
Doronomyrmex goesswaldi A1
Leptopilina australis
Cadra cautella
Phlebotomus papatasi (Israel)
Gnamptogenys menadensis
Tetranychus urticae
Doronomyrmex pacis A3
Cadra cautella 2
Acraea encedon
Glossina austeni
Asobara tabida
Culex quinquefasciatus
Asobara tabida 3
Drosophila sechellia
Drosophila simulans (Hawaii)
Cataglyphis iberica
Culex pipiens (ESPRO)
Trichopria drosophilae
Isopods
Formica rufa
Teleutomyrmex schneideri
Bactocera sp 1 AscD
Aedes albopictus (Houston)
Myrmica sulcinodis (Russia)
Formica fusca (KH B)
Formica pratensis
Drosophila simulans (Watsonville)
Myrmica sulcinodis (Samso D)
Dacus destillatoria
Leptothorax acervorum
Formica fusca (SJW B)
Formica fusca (Mols D)
Formica truncorum
Doronomyrmex kutteri A
Doronomyrmex pacis A4
Formica polyctena
Neochrysocharis formosa
Doronomyrmex pacis B1
Doronomyrmex goesswaldi A2
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Multiple infections
Solenopsis invicta (imported)
Coleomegilla maculata lengi
Doronomyrmex pacis A1
Myrmica sulcinodis (Pyrenees)
Plutella xylostella
Laodelphax striatellus
Diaphorina citri
Porcellionides pruinosus
Acraea encedon 1
Trichopria Tsp2
Myrmica rubra
Acromyrmex insinuator A
Formica lemani
Plagiolepis pygmaea
Sphaeroma rugicauda
Dryinid wasp sp
Trichogramma kaykai (LC110)
Bactocera cucurbitae
Muscidifurax uniraptor
Trichogramma bourarachae
Tribolium madens
Tribolium confusum
Rhinophoridae unid
Leptopilina heterotoma 2
Doronomyrmex kutteri B
Glossina morsitans centralis
Doronomyrmex pacis B2
Trichogramma spp.
Coleomegilla maculata
Adalia bipunctata B
Drosophila bifasciata
Nasonia vitripennis A
Aedes albopictus (Houston)
Drosophila simulans (Coffs Harbour)
Adalia bipunctata A
A
B
Acromyrmex octospinosus B3
Drosophila melanogaster (Cairns)
Drosophila melanogaster (CantonS)
Acromyrmex insinuator B1
Acromyrmex echinatior B
Drosophila simulans (Riverside)
Solenopsis invicta (native)
Acromyrmex echinatior A1
Acromyrmex octospinosus B1
Solenopsis richteri A
Acromyrmex octospinosus B2
Doronomyrmex pacis A2
Acromyrmex insinuator B2
Myrmica sabuleti
Solenopsis invicta A (native)
Telenomus nawai
Acromyrmex octospinosus A1
Encarsia formosa
Diplolepis rosae
Doronomyrmex goesswaldi A1
Leptopilina australis
Cadra cautella
Phlebotomus papatasi (Israel)
Gnamptogenys menadensis
Tetranychus urticae
Doronomyrmex pacis A3
Cadra cautella 2
Acraea encedon
Glossina austeni
Asobara tabida
Culex quinquefasciatus
Asobara tabida 3
Drosophila sechellia
Drosophila simulans (Hawaii)
Cataglyphis iberica
Culex pipiens (ESPRO)
Trichopria drosophilae
Isopods
Formica rufa
Teleutomyrmex schneideri
Bactocera sp 1 AscD
Aedes albopictus (Houston)
Myrmica sulcinodis (Russia)
Formica fusca (KH B)
Formica pratensis
Drosophila simulans (Watsonville)
Myrmica sulcinodis (Samso D)
Dacus destillatoria
Leptothorax acervorum
Formica fusca (SJW B)
Formica fusca (Mols D)
Formica truncorum
Doronomyrmex kutteri A
Doronomyrmex pacis A4
Formica polyctena
Neochrysocharis formosa
Doronomyrmex pacis B1
Doronomyrmex goesswaldi A2
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Wolbachia in Leafcutter Ants

• Two free-living species (A. octospinosus, A.
  echinatior) have multiple Solenopsis-like
  Wolbachia infections
• Infection males lt gynes workers ? possibly
  partial male killers
• No evidence for abnormal sex ratios

Neochrysocharis Eulophidae
Dacus destillatoria

Drosophila simulans

Drosophila melanogaster

Aedes albopictus

Acromyrmex insinuator A1
InsA


Muscidifurax uniraptor

Nasonia vitripennis
A

Drosophila bifasciata

Drosophila simulans

Formica truncorum

Asobara tabida

Acromyrmex echinatior A1
Solenopsis richteri

InvA

Acromyrmex octospinosus A1

Solenopsis invicta

Armadillidium vulgare
Culex pipiens

Encarsia Formosa
Diplolepis rosae

Acromyrmex insinuator B2
Naw


Telenomus nawai
Adalia bipunctata
B


Trichogramma kaykai

Tribolium madens
Acraea encedon

Solenopsis invicta

Acromyrmex octospinosus B3

Acromyrmex octospinosus B2

Acromyrmex insinuator B1
InvB

Solenopsis invicta


Acromyrmex echinatior Bc
Van Borm, Wenseleers, Billen Boomsma, Mol.
Phyl. Evol., in press Van Borm, Wenseleers,
Billen Boomsma (2001) J. Evol. Biol. 13
277-280.
Acromyrmex octospinosus B1
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Wolbachia in Leafcutter Ants

• Several unrelated Wolbachia infections in
  inquiline A. insinuator
• Equally common in males and females ? cytoplasmic
  incompatibility?

Neochrysocharis Eulophidae
Dacus destillatoria

Drosophila simulans

Drosophila melanogaster

Aedes albopictus

Acromyrmex insinuator A1
InsA


Muscidifurax uniraptor

Nasonia vitripennis
A

Drosophila bifasciata

Drosophila simulans

Formica truncorum

Asobara tabida

Acromyrmex echinatior A1
Solenopsis richteri

InvA

Acromyrmex octospinosus A1

Solenopsis invicta

Armadillidium vulgare
Culex pipiens

Encarsia Formosa
Diplolepis rosae

Acromyrmex insinuator B2
Naw


Telenomus nawai
Adalia bipunctata
B


Trichogramma kaykai

Tribolium madens
Acraea encedon

Solenopsis invicta

Acromyrmex octospinosus B3

Acromyrmex octospinosus B2

Acromyrmex insinuator B1
InvB

Solenopsis invicta


Acromyrmex echinatior Bc
Van Borm, Wenseleers, Billen Boomsma, Mol.
Phyl. Evol., in press Van Borm, Wenseleers,
Billen Boomsma (2001) J. Evol. Biol. 13
277-280.
Acromyrmex octospinosus B1
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No match with host phylogeny
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Sequencing conclusions

• No host-parasite coevolution
• But distinct ant Wolbachia clades implies
  degree of host specialisation
• Frequent horizontal transmission
• Single ants may be infected with up to 6
  different strains
• Different populations usually, but not always,
  infected by same strains

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Conclusions

• Does Wolbachia occur in ant societies? YES, IN
  HIGH FREQUENCY
• Alternative explanation for female biased
  sex-ratios?NO STRONG EVIDENCEOther
  effects?INCOMPATIBILITY (SPECIATION?)
• Host-parasite coevolution? NO, OCCASIONAL
  HORIZONTAL TRANSMISSION

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References
S. Van Borm, T. Wenseleers, J. Billen and J.J.
Boomsma (2002) Cloning and sequencing of wsp
encoding gene fragments reveals a diversity of
co-infecting Wolbachia strains in Acromyrmex
leafcutter ants. Molecular Phylogenetics and
Evolution, in press. T. Wenseleers, L.
Sundström and J. Billen (2002) Deleterious
Wolbachia in the ant Formica truncorum.
Proceedings of the Royal Society of London Series
B-Biological Sciences, 269 623-629. S. Van
Borm, T. Wenseleers, J. Billen and J.J. Boomsma
(2001) Wolbachia in leafcutter ants a widespread
symbiont that may induce male killing or
incompatible matings. Journal of Evolutionary
Biology, 14 805-814. T. Wenseleers (2001)
Conflict from Cell to Colony. Ph.D. thesis,
University of Leuven, Belgium, 205 pp. Advisor
Prof. Dr. J. Billen. D. Grasso, T. Wenseleers,
A. Mori, F. Le Moli and J. Billen (2000)
Thelytokous worker reproduction and lack of
Wolbachia infection in the harvesting ant Messor
capitatus. Ethology, Ecology Evolution, 12
309-314. T. Wenseleers and J. Billen (2000) No
evidence for Wolbachia-induced parthenogenesis in
the social Hymenoptera. Journal of Evolutionary
Biology, 13 277-280. T. Wenseleers, F. Ito,
S. Van Borm, R. Huybrechts, F. Volckaert and J.
Billen (1998) Widespread occurrence of the
micro-organism Wolbachia in ants. Proceedings of
the Royal Society of London Series B-Biological
Sciences, 265 1447-1452.
PDFs at www.shef.ac.uk/uni/projects/tapla
b/twpub.html
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Acknowledgements
Prof. Dr. J. Billen Dr. F. Ito Prof. Dr. J.J.
Boomsma Dr. F.L.W. Ratnieks Dr. D.A. Grasso Dr.
L. Sundström Prof. Dr. R. Huybrechts S. Van Borm
Prof. Dr. F. Volckaert Academy
of Finland, British Council,
FWO-Vlaanderen,
Vlaamse Leergangen,
EU Social Evolution INSECTS

networks, Marie Curie