my research current research : caste conflict in social insects (stingless bees & termites)

My researchCurrent research :

Caste conflict in social insects (stingless bees & termites)

Sex allocationSex allocation

queen50% females

workers75% females

INTRAGENOMIC INTRAGENOMIC CONFLICTCONFLICT

autosome 50% females

plasmagenes100% females

sperm100% females

PARENT-PARENT-OFFSPRING OFFSPRING CONFLICTCONFLICT

Wolbachia

Maternally transmitted symbiont that manipulates host to produce female biased broods

“Cytoplasmic sex ratio distorter”

Alpha-proteobacterium

Occurs mainly in arthropods (insects+Crustacea) + nematodes

FemaleBiased

Sex-Ratios

Male Killing

Feminisation

Parthenogenesis Induction

Effects on host reproduction

NormalOffspring

Production

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

Cytoplasmic incompatibility

Inviable

++--

----

--

++++

++

Phylogeny

Oth

er a

lpha

pro

teobacte

ria

Ehrlichieae

Neorickettsia

Gamm

a

prote

obac

teria

0.1

Wolbachia

CaedibacterMtK

MitochondriaCMS

Orientia MK

Rickettsia MK

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?

Polymerase Chain Reaction using Specific Primers

Targets: ftsZ and wsp Wolbachia genes

Positive, negative and nuclear DNA (18S rDNA) controls

Negative samples retested twice

Methodology: PCR Assay

Methodology: PCR Assay

High Incidence Worldwide

Indonesia

Wenseleers et al. (1998) Proceedings of the Royal Society of London

# species=50

Florida

Jeyaprakash & Hoy (2000) Insect Molecular Biology

# species=10

Panama

Van Borm et al. (2001) Journal of Evolutionary Biology

# species=7

Europe

# species=50

3451 samples

Morphological evidence

Present in trophocytes and oocytes

Electron and light microscopical (DAPI) evidence

Aims

Does Wolbachia occur in ant societies and if so in what frequency? YES, IN HIGH FREQUENCY



Parthenogenesis induction?

6 Parthenogenetic Ants Cape honeybee

Cataglyphis cursor Apis mellifera capensisCataglyphis piliscapa

Pristomyrmex pungens

Cerapachys biroi

Messor capitatus

Platythyrea punctata

250 samples, avg. 6 cols./species

Grasso et al. (2000) Ethology, Ecology & Evolution 12:309-314Wenseleers & Billen (2000) Journal of Evolutionary Biology 13:277-280

None infected.Wolbachia does not

induce parthenogenesis in

ants.

Wolbachia in F. truncorum

With: Lotta Sundström University of Helsinki

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?

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

Predictions

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

r2 = 0.0097

0

0.25

0.5

0.75

1

0.00 0.20 0.40 0.60 0.80 1.00

Percent infected workers

Inve

stm

ent i

n fe

mal

es

GLM Effects F p

No. of mates 4.88 0.04Infection rate 0.85 0.37Colony size 0.69 0.42

Infection and sex-ratio


r2 = 0.03

0

4

8

12

0.00 0.20 0.40 0.60 0.80 1.00

Proportion infected adult workers

Per

cap

ita

pro

du

ctio

n

Worker production

r2 = 0.28

0

4

8

12

0.00 0.20 0.40 0.60 0.80 1.00

Proportion infected adult workers

Per

cap

ita

pro

du

ctio

n

Sexual production

GLM

Effects F p F p

No. of mates 2.11 0.16 2.5 0.13

Infection rate 2.89 0.11 10.2 0.005

Infection and colony fitness


p<0.015p<0.0001

0

25

50

75

100

Pe

rce

nt

infe

cte

d

Sexuals Adult workers

Worker pupae

Infection rates

N=296 N=158 N=387

Adaptiveclearance to

reduce colony load?

Wenseleers, Sundström & Billen (2002) Proceedings of the Royal Society of London B, 269: 623-629

p < 0.0001

0

25

50

75

100

Pe

rce

nt

infe

cte

d

Clearance in lab experiments

N=89 N=90

After 2 month exposure to

20°C

Worker pupae

7 colonies

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

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

0.4

0.5

0.6

0.7

0.8

0.9

1

Untreated Treated

Pri

ma

ry s

ex

-ra

tio

2 = 10.51, p < 0.001

Antibiotics experiments

4 coloniesN=70

7 coloniesN=152

Aims

Does Wolbachia occur in ant societies and if so in what frequency? YES, IN HIGH FREQUENCY



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)

Methodology: Sequencing

28 sequencesAligned with previously sequenced relatives

So

len

op

sis

invi

cta

(im

po

rted

) C

ole

om

egill

a m

acu

lata

len

gi

Dia

ph

ori

na

citr

i P

lute

lla x

ylo

stel

la L

aod

elp

hax

str

iate

llus

Acr

aea

ence

do

n 1

Tri

cho

pri

a T

sp2

Dry

inid

was

p sp

Por

celli

onid

es p

ruin

osus

Sph

aero

ma

rugi

caud

a

Bac

toce

ra c

ucur

bita

e

Trib

oliu

m m

aden

s

Trib

olium

confu

sum

Rhin

ophoridae

unid

Doro

nomyrmex kutte

ri B

Doro

nomyrmex pacis B

2

Trichogramma spp.

Adalia bipunctata B

Coleomegilla maculata

Adalia bipunctata A

Acromyrmex octospinosus B3

Acromyrmex insinuator B1

Acromyrmex echinatior B

Solenopsis invicta (native)

Acromyrmex octospinosus B1 Acromyrmex octospinosus B2 Acromyrmex insinuator B2

Myrmica sabuleti Telenomus nawai Encarsia formosa

Diplolepis rosae

Leptopilina australis

Cadra cautella

Tetranychus urticae

Acraea encedon

Culex quinquefasciatus

Culex pipiens (ESPRO)

Drosophila simulans (W

atsonville)

Aedes albopictus (Houston)

Doronom

yrmex pacis B

1

Isopods

Trichopria drosophilae

Asobara tabida

Myrm

ica sulcin

od

is (Sam

so D

)

Myrm

ica sulcin

od

is (Ru

ssia)

Teleu

tom

yrmex sch

neid

eri

Neo

chryso

charis fo

rmo

sa

Fo

rmic

a ru

faD

acu

s d

esti

llato

ria

Do

ron

om

yrm

ex g

oes

swal

di A

2

Do

ron

om

yrm

ex p

acis

A4

Do

ron

om

yrm

ex k

utt

eri A

Fo

rmic

a fu

sca

(Mo

ls D

)

Fo

rmic

a fu

sca

(SJW

B)

Fo

rmic

a fu

sca

(KH

B)

Lep

toth

ora

x ac

ervo

rum

Bac

toce

ra s

p 1

Asc

D

Cat

agly

phis

iber

ica

Glo

ssin

a au

sten

i

Form

ica

poly

cten

a

Form

ica

trunc

orum

Formic

a pra

tensi

s

Asobara t

abida 3

Drosophila

sechellia

Drosophila sim

ulans (Hawaii)

Cadra cautella 2

Doronomyrmex pacis A3

Gnamptogenys menadensis

Phlebotomus papatasi (Israel)

Doronomyrmex goesswaldi A1

Acromyrmex octospinosus A1Solenopsis invicta A (native)Doronomyrmex pacis A2

Solenopsis richteri A

Acromyrmex echinatior A1

Drosophila simulans (Riverside)

Drosophila melanogaster (CantonS)

Drosophila melanogaster (Cairns)

Drosophila simulans (Coffs Harbour)


Nasonia vitripennis A

Drosophila bifasciata

Glossina morsitans centralis

Leptopilina heterotoma 2

Trichogramm

a bourarachae

Trichogramm

a kaykai (LC110)

Muscidifurax uniraptor

Acrom

yrmex insinuator A

Plagiolepis pygmaea

Myrm

ica sulcinodis (Pyrenees)

Formica lem

ani

Myrm

ica rub

ra

Do

ron

om

yrmex p

acis A1

0.050(25 MY)

A B

High strain diversity

So

len

op

sis

invi

cta

(im

po

rted

) C

ole

om

egill

a m

acu

lata

len

gi

Dia

ph

ori

na

citr

i P

lute

lla x

ylo

stel

la L

aod

elp

hax

str

iate

llus

Acr

aea

ence

do

n 1

Tri

cho

pri

a T

sp2

Dry

inid

was

p sp

Por

celli

onid

es p

ruin

osus

Sph

aero

ma

rugi

caud

a

Bac

toce

ra c

ucur

bita

e

Trib

oliu

m m

aden

s

Trib

olium

confu

sum

Rhin

ophoridae

unid

Doro

nomyrmex kutte

ri B

Doro

nomyrmex pacis B

2

Trichogramma spp.

Adalia bipunctata B


Adalia bipunctata A







Diplolepis rosae


Cadra cautella

Tetranychus urticae

Acraea encedon




atsonville)


Doronom

yrmex pacis B

1

Isopods


Asobara tabida

Myrm

ica sulcin

od

is (Sam

so D

)

Myrm

ica sulcin

od

is (Ru

ssia)

Teleu

tom

yrmex sch

neid

eri

Neo

chryso

charis fo

rmo

sa

Fo

rmic

a ru

faD

acu

s d

esti

llato

ria

Do

ron

om

yrm

ex g

oes

swal

di A

2

Do

ron

om

yrm

ex p

acis

A4

Do

ron

om

yrm

ex k

utt

eri A

Fo

rmic

a fu

sca

(Mo

ls D

)

Fo

rmic

a fu

sca

(SJW

B)

Fo

rmic

a fu

sca

(KH

B)

Lep

toth

ora

x ac

ervo

rum

Bac

toce

ra s

p 1

Asc

D

Cat

agly

phis

iber

ica

Glo

ssin

a au

sten

i

Form

ica

poly

cten

a

Form

ica

trunc

orum

Formic

a pra

tensi

s

Asobara t

abida 3

Drosophila

sechellia

Drosophila sim

ulans (Hawaii)

Cadra cautella 2

















Trichogramm

a bourarachae

Trichogramm

a kaykai (LC110)


Acrom

yrmex insinuator A

Plagiolepis pygmaea

Myrm


Formica lem

ani

Myrm

ica rub

ra

Do

ron

om

yrmex p

acis A1

0.050(25 MY)

A B

No match with host phylogeny

Acrom

yrmex insinuator A

Plagiolepis pygmaea

Myrm


Formica lem

ani

Myrm

ica rub

ra

Do

ron

om

yrmex p

acis A1

Hosts diverged 35 MY ago, but share a recently evolved W. strain

(1.7 MY old)

Doro

nomyrmex kutte

ri B

Doro

nomyrmex pacis B

2

Doronom

yrmex pacis B

1

Do

ron

om

yrm

ex g

oes

swal

di A

2

Do

ron

om

yrm

ex p

acis

A4

Do

ron

om

yrm

ex k

utt

eri ADoronomyrm

ex pacis A3Doronomyrmex goesswaldi A1


Do

ron

om

yrmex p

acis A1

So

len

op

sis

invi

cta

(im

po

rted

) C

ole

om

egill

a m

acu

lata

len

gi

Dia

ph

ori

na

citr

i P

lute

lla x

ylo

stel

la L

aod

elp

hax

str

iate

llus

Acr

aea

ence

do

n 1

Tri

cho

pri

a T

sp2

Dry

inid

was

p sp

Por

celli

onid

es p

ruin

osus

Sph

aero

ma

rugi

caud

a

Bac

toce

ra c

ucur

bita

e

Trib

oliu

m m

aden

s

Trib

olium

confu

sum

Rhin

ophoridae

unid

Doro

nomyrmex kutte

ri B

Doro

nomyrmex pacis B

2

Trichogramma spp.

Adalia bipunctata B


Adalia bipunctata A







Diplolepis rosae


Cadra cautella

Tetranychus urticae

Acraea encedon




atsonville)


Doronom

yrmex pacis B

1

Isopods


Asobara tabida

Myrm

ica sulcin

od

is (Sam

so D

)

Myrm

ica sulcin

od

is (Ru

ssia)

Teleu

tom

yrmex sch

neid

eri

Neo

chryso

charis fo

rmo

sa

Fo

rmic

a ru

faD

acu

s d

esti

llato

ria

Do

ron

om

yrm

ex g

oes

swal

di A

2

Do

ron

om

yrm

ex p

acis

A4

Do

ron

om

yrm

ex k

utt

eri A

Fo

rmic

a fu

sca

(Mo

ls D

)

Fo

rmic

a fu

sca

(SJW

B)

Fo

rmic

a fu

sca

(KH

B)

Lep

toth

ora

x ac

ervo

rum

Bac

toce

ra s

p 1

Asc

D

Cat

agly

phis

iber

ica

Glo

ssin

a au

sten

i

Form

ica

poly

cten

a

Form

ica

trunc

orum

Formic

a pra

tensi

s

Asobara t

abida 3

Drosophila

sechellia

Drosophila sim

ulans (Hawaii)

Cadra cautella 2

















Trichogramm

a bourarachae

Trichogramm

a kaykai (LC110)


Acrom

yrmex insinuator A

Plagiolepis pygmaea

Myrm


Formica lem

ani

Myrm

ica rub

ra

Do

ron

om

yrmex p

acis A1

0.050(25 MY)

A B

Multiple infections

Doro

nomyrmex pacis B

2

Doronom

yrmex pacis B

1Do

ron

om

yrm

ex p

acis

A4



Do

ron

om

yrmex p

acis A1

Multi infections may drive speciation

events!


Acromyrmex octospinosus A1

Acromyrmex octospinosus B3Acromyrmex octospinosus B2

Acromyrmex echinatior BcAcromyrmex octospinosus B1

Wolbachia in Leafcutter Ants

Van Borm, Wenseleers, Billen & Boomsma, Mol. Phyl. Evol., in pressVan Borm, Wenseleers, Billen & Boomsma (2001) J. Evol. Biol. 13: 277-280.

Neochrysocharis Eulophidae Dacus destillatoria Drosophila simulansDrosophila melanogaster Aedes albopictus Acromyrmex insinuator A1 Muscidifurax uniraptor

Nasonia vitripennis

Drosophila bifasciata Drosophila simulans Formica truncorum

Asobara tabida

Solenopsis richteri

Solenopsis invicta

Armadillidium vulgare Culex pipiens Encarsia Formosa Diplolepis rosae Acromyrmex insinuator B2 Telenomus nawai Adalia bipunctata Trichogramma kaykai Tribolium madens Acraea encedon Solenopsis invicta

Acromyrmex insinuator B1 Solenopsis invicta

A

B

InvA

InvB

Naw

InsA

56

65

100

74

100

100

76

100

8788

100

70

70

96

99

85

9696

79

85

71

93

69

Two free-living species (A. octospinosus, A. echinatior) have multiple “Solenopsis-like” Wolbachia infections

Infection males < gynes + workers possibly partial male killers

No evidence for abnormal sex ratios


Acromyrmex octospinosus A1

Acromyrmex octospinosus B3Acromyrmex octospinosus B2

Acromyrmex echinatior BcAcromyrmex octospinosus B1

Wolbachia in Leafcutter Ants

Neochrysocharis Eulophidae Dacus destillatoria Drosophila simulansDrosophila melanogaster Aedes albopictus Acromyrmex insinuator A1 Muscidifurax uniraptor

Nasonia vitripennis

Drosophila bifasciata Drosophila simulans Formica truncorum

Asobara tabida

Solenopsis richteri

Solenopsis invicta

Armadillidium vulgare Culex pipiens Encarsia Formosa Diplolepis rosae Acromyrmex insinuator B2 Telenomus nawai Adalia bipunctata Trichogramma kaykai Tribolium madens Acraea encedon Solenopsis invicta

Acromyrmex insinuator B1 Solenopsis invicta

A

B

InvA

InvB

Naw

InsA

56

65

100

74

100

100

76

100

8788

100

70

70

96

99

85

9696

79

85

71

93

69

Several unrelated Wolbachia infections in inquiline A. insinuator

Equally common in males and females cytoplasmic incompatibility?

Van Borm, Wenseleers, Billen & Boomsma, Mol. Phyl. Evol., in pressVan Borm, Wenseleers, Billen & Boomsma (2001) J. Evol. Biol. 13: 277-280.

No match with host phylogeny

pratensis

lemani

fusca

rufa

O

100

99

polyctena

truncorum84100

0.02(10 MY)

...and their symbionts

rufa

polyctena

pratensis

truncorum

lemani

fusca

O

Formica hosts...

Gyllenstrand, unpublished

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

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

ReferencesS. 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/taplab/twpub.html

http://www.shef.ac.uk/uni/projects/taplab/pdf/vbwbbjevolbiol2001.pdf

http://www.shef.ac.uk/uni/projects/taplab/pdf/gwmlmbeee2000.pdf

http://www.shef.ac.uk/uni/projects/taplab/pdf/wbjevolbiol2000.pdf

AcknowledgementsProf. Dr. J. Billen Dr. F. ItoProf. Dr. J.J. Boomsma Dr. F.L.W. RatnieksDr. 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

my research current research : caste conflict in social insects (stingless bees & termites)

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