D. suzukii

Evolution and Ecology of
Drosophila suzukii: a comparison
between native and invaded areas
Masahito T. Kimura,
Hokkaido University,
Japan
Gianfranco Anfora
Fondazione E. Mach
Italy

Talk outline
Phylogeny
Alert on species identification
Seasonal cycles
Who is damaged by D. suzukii: host range
and preferences
Who benefits from D. suzukii?
NATIVE (Japan) vs INVADED (Trentino, Italy) AREAS

Phylogenetic position of D. suzukii
● D. suzukii belongs to the melanogaster species group
which includes the following subgroups
the melanogaster species subgroup (9: the number of species)
the takahashii species subgroup (15)
the suzukii species subgroup (18)
the ficusphila species subgroup (6)
the elegans species subgroup (5)
the eugracilis species subgroup (1)
the rhopaloa species subgroup (5)
the denticulata species subgroup (4)
the flavohirta species subgroup (1)
the montium species subgroup (89)
the ananassae species subgroup (25)
Some taxonomists treat
these two subgroups as
“species group”.
(Ref.: Lemeunier et al. 1984; van der Linde & Houle, 2008; Toda, personal comm.)

Phylogenetic position of D. suzukii
phylogeny “traditional classification”
D. melanogaster
D. takahashii
the melanogaster species subgroup
D. lutescens
the takahashii species subgroup
D. mimetica
D. suzukii
D. pulchrella
D. biarmipes
D. tristipennis
D. unipectinata
D. lucipennis
D. elegans
the core suzukii lineage
the suzukii species subgroup
the elegans species subgroup
The suzukii species subgroup is polyphyletic
(Ref.: van der Linde & Houle, 2008; Takamori, unpubl.)

Distributions of D. suzukii and its relatives
The core suzukii lineage
D. suzukii
D. subpulchrella
D. pulchrella
D. immacularis
D. apodemata
D. biarmipes
D. plagiata
India, South East Asia, China, Japan
India, South East Asia, China, Japan
India, South East Asia, southern China
India, South East Asia, southern China
New Guinea
India, South East Asia, southern China
South Africa
D. suzukii and D. subpulchrella are distributed from tropical to temperate
regions
In tropical regions, these species usually occur at mid to high altitudes
(1000-2000 m)
Thus, members of this lineage are adapted to rather cool climates.
(Ref.: Okada 1966; Bock & Wheeler 1973; Okada & Carson 1983;
Lemeunier et al. 1984; Tscas & Chassagnard 1995;Takamori et al. 2006)

Ovipositors and ovipositing habits of D. suzukii and its
relatives
Long and strongly sclerotized
0.05 mm
D. suzukii D. subpulchrella D. biarmipes
Oviposition
Long, curved and
strongly sclerotized
(D. pulchrella and D.
immacularis have
almost identical
ovipositors)
Short and
weakly
sclerotized
(D. plagiata
has a similar
ovipositor)
On fresh fruits
Probably on fresh fruits Probably on
fermenting
*Ovipositor of D. apodemata is not known
fruits
(Ref.: Kimura et al. 1977; Nishiharu 1980; Mitsui et al. 2006, 2010)

Evolution of D. suzukii and its relatives
The core suzukii lineage has evolved, probably in mid-to-high altitude
areas of tropical or subtropical Asia
The ancestor of this core lineage had short, weakly sclerotized ovipositor
and oviposited on fermenting fruits, like extant D. biarmipes (or
D. plaginata).
Most species of the related subgroups also have short, weakly
sclerotized ovipositors and oviposit on fermenting fruits,
suggesting that these are the ancestral features of the
melanogaster species group.
The ancestor of the suzukii-pulchrella-subpulchrella-immacularis cluster
became to oviposit in fresh fruits and evolved long, strongly sclerotized
ovipositor.
D. suzukii would have first branched off in the suzukii-pulchrella-,
subpulchrella-immacularis cluster, but it is not known where,
when and how.

0.65
1.00
Different genes support different evolutionary
scenarios for D. suzukii
mitochondrial genes
Melanogaster
subgroup
Takahashi
subgroup
0.97
?
D.suzukii
D.biarmipes
D.subpulchrella
D.pulchrella
One single origin ( ) of new ecological behaviour ( )
Suzukii
subgroup
1.00
0.83
?
1.00
Takahashi
subgroup
nuclear genes
Melanogaster
subgroup
D.subpulchrella
D.pulchrella
D.suzukii
D.biarmipes
Two independent origins ( ) of new ecological
behaviour
Alternatively one gain ( ) and one loss ( ) in D.
biarmipes)
Suzukii
subgroup

0.65
1.00
mitochondrial genes
Melanogaster
subgroup
Takahashi
subgroup
0.97
WHY THE DISCREPANCY ?
1. A sever incomplete lineage sorting due to
speciation compressed in time
2. Mitochondrial genes are biased (Wolbachia,
metabolic adaptations)
3. Some nuclear genes are biased (but why)?
4. Species have been mis-recognised
?
D.suzukii
D.biarmipes
Different genes support different evolutionary
scenarios for D. suzukii
D.subpulchrella
D.pulchrella
Suzukii
subgroup
1.00
SOLUTION ?
0.83
1.00
Phylogenomics using:
nuclear genes
Takahashi
subgroup
Melanogaster
subgroup
D.pulchrella
D.suzukii
D.biarmipes
- suzukii (genome sequencing)
?
D.subpulchrella
- subpulchrella and pulchrella (transcriptomes planned)
- biarmipes and others (genomes already sequenced)
Suzukii
subgroup

Drosophila subpulchrella Drosophila suzukii

Distributions of D. suzukii and D. subpulchrella in Japan
30 N
40 N
Nagano
Iriomote-jima
Sapporo
Kume-jima
Tokyo
Sapporo
Tokyo
Kume-jima
Iriomote-jima
January
mean
temperature
- 3.6 C
16.9 C
18.3 C
D. suzukii
1.77 %
20.54 %
0.63 %
0.001%
D. subpulchrella
Not recorded
0.33 %
Not recorded
Not recorded
Frequency (%) of D. suzukii and D. subpulchrella
in samples of drosophilid flies collected by traps
baited with fermenting banana.
D. suzukii and D. subpulchrella are warm-temperate species; they are less abundant in
cool-temperate regions (Sapporo) and subtropical regions (Iriomote-jima and Kume-jima).
4.2 C
D. suzukii is much more abundant than D. subpulchrella, but its reason is unknown.
(Ref.: Momma 1964; Hirai. 2000; Kondo & Kimura 2006; Beppu 2006; Kimura unpuble.)

Fruits attacked by D. suzukii and D. subpulchrella in Japan
D. suzukii
D. subpulchrella
Wild fruits (genus is shown) Cultivated fruits (genus)
Prunus
Morus
Rubus
Aucuba
Cornus
Alangium
Diospyros
Torreya
Prunus
Morus
Rubus
Cornus
Viburnum
Vaccinium
Gaultheria
Elaeagnus
Broussonetia
Actinida
Taxus
Cephalotaxus
Broussonetia
Diospyros
Actinida
Cephalotaxus
Cherry, Plum, Apricot,
Peach (Prunus)
Apple (Malus)
Pear (Pirus)
Strawberry (Rubus)
Loquat (Eriobotrya)
Grape (Vitis)
Persimmon (Diospyros)
Silverberry (Elaeagnus)
Not reported, may be
misidentified as D.
suzukii.
(Ref.: Kanzawa 1939; Kimura et al. 1977; Nishiharu 1980; Mitsui et al. 2006, 2010)

Bar-coding to monitor presence of D. subpulchrella
D.pulchrella
D.subpulchrella
D.suzukii
Similar
wing
patterns
Washington
Spain
SanDiego5
California G
SanDiego
California F
SanDiego3
California D
SanDiego2
California C
Japan
China
SanDiego4
D.suzukii
California B
SantaCruz
suzukii
D.pulchrella
Slightly
different
Ovipositor
COX1 bar-coding has good
discriminating power but
D.subpulchrella not yet
sampled
D.trilutea
D.biarmipe
Putative
similar
ecology
D.simulans
D.melanoga
D.takahash

Number of individuals
Seasonal life cycle of D. suzukii in central Japan
200
150
100
50
0
40
20
0
800
600
400
200
0
3000
2000
1000
0
Nagano: 2000 m
A
A
A
M J J A S O N
Nagano: 1460-1540 m
M J J A S O N
Nagano: 500-680 m
A
1990
1990
1990
M J J A S O N
Tokyo: 50 m
2001-2002
M J J A S O N
Trap collections at different altitudes in
central Japan (Nagano, 500-2000 m,
Tokyo, 50 m).
Ovarian conditions
Mature
Developing
Undeveloped
D J F M
At low altitude, the number of individuals
collected decreased in summer probably
due to migration to high altitudes, and in
winter due to low activity .
At high altitude, this species
would not be able to overwinter.
Its summer populations at high
altitudes would be formed by
migrants from low altitudes.
This species pass the winter in
reproductive diapause at low
altitudes
(Ref.: Mitsui et al. 2010)

Seasonal life cycle of D. suzukii
in northern Italy
S. Michele a/A 2010:
Grape 260 m
Pergine 2011:
Cherry 600 m
Passo Redebus 2010:
Forest 1435 m

Oviposition of D. suzukii on wild cherry fruits in Tokyo
Fresh fruits on trees and fallen fruits were
collected in the fields, and examined for
the emergence of Drosophila flies.
Fruits on trees
No. of fruits
D. suzukii
Others
Fruits on ground
No. of fruits
D. suzukii
Others
Site A Site B
120 50
298 80
0 0
Site C Site D
100 100
56 76
67 82
Site E
100
38
131
D. suzukii probably oviposits only on fruits on trees, whereas the
others (D. lutescens and D. rufa) oviposit only on fallen fruits
(Ref.: Mitsui et al. 2006)

Oviposition of D. suzukii on wild cherry fruits in Tokyo
Wild cherry fruits change color and hardness with ripeness.
Light red Red Black
Number of D. suzukii eggs (per fruit) at different stages
Tree A 0
Tree B
D. suzukii oviposits on ripe fruits
Light red Red
1.15
0 1.49
Black
1.75
2.38
(Ref.: Mitsui et al. 2006)

Parasitoids of D. suzukii in Tokyo, central Japan
Larval parasitoids
Pupal parasitoid
Ganaspis sp. affinis xanthopoda (Figitidae):
This species is not discriminated from G. xanthopoda by
morphology, but differs in nucleotide sequences of COI and ITS1 and
ITS2 and host selection.
Leptopilina japonica (Figitidae)
Asobara japonica (Braconidae)
This species, A. tabida and A. rufescens, have been confirmed to
parasitize D. suzukii in the fields.
Trichopria sp. (Diapriidae)
(Ref.: Kanzawa 1939; Ideo et al. 2008; Mitsui et al. 2007;
Kasuay et al. unpubl.)

Parasitoids of D. suzukii in Trentino
Several individuals caught in monitoring traps:
Probably Asobara tabida (Nees) (Braconidae, Alysiinae). It is attracted to
fermenting fruits and attacks drosophilid larvae growing there

Parasitoids of D. suzukii in Trentino
Ectoparasitic larvae
Eggs found in D. suzukii abdomen (Pipunculidae?)

Parasitism of D. suzukii in Tokyo, central Japan
Fruits on trees
Site
A
No.
of
fruits
Fruits on ground
Site
A
No. of
D. suzukii
pupae
319 367 7.1
No.
of
fruits
No. of
D. suzukii
pupae
737 1152 1.8
% of parasitism by
Gs Lj Ar
- -
% of parasitism by
Gs Lj Ar
- 0.4
B 1772 1528 4.1 - 0.1
C 1064 891 6.4 0.2 -
Ganaspis sp. (Gs) is the major parasitoid of D. suzukii in central Japan. This
parasitoid attacks larvae in fruits on trees. Leptopilina japonica (Lj) and Asobara
rufescens (Ar) may attack larvae in fallen fruits

Host selection of Ganaspis sp.
Experiments
Six Drosophila species. Fly females were placed
in vials with cherry fruits and allowed oviposit for
a day (intact cherry fruits were provided for D.
suzukii, while fruits that were pricked by needle
were provided for the others). Two days after, five
Ganaspis sp. females were placed in the vials for a
day.
In addition, D. suzukii females were placed in
vials with Drosophila medium and allowed to
oviposit for a day. Two days after, five Ganaspis
sp. females were placed in the vials for a day.
D. suzukii, D. lutescens, D. auraria,
D. biauraria, D. triauraria, D. rufa.
These species are common fruits-feeders in Tokyo. Except D.
suzukii, they oviposit on fermenting fruits.

Host selection of Ganaspis sp.
Cherry fruits
D. suzukii
D. lutescens
D. auraria
D. biauraria
D. triauraria
D. rufa
Drosophila medium
D. suzukii
No. of
vials
17
5
2
1
2
2
No. of
vials
No. of emergence
fly wasps
408
148
318
16
196
122
129
0
0
0
0
0
No. of emergence
fly wasps
17 174 0
Ganaspis sp. attacks
only D. suzukii.
Ganaspis sp. does
not attack D. suzukii
in Drosophila
medium

Host selection of Leptopilina japonica and Asobara Japonica
Experiments
These two parasitoids attack Drosophila larvae in Drosophila medium.
Wasps were observed for oviposition.
Drosophila larvae oviposited by wasps were placed in vials with
food medium and examined for emergence of flies or wasps.
D. suzukii
D. lutescens
D. auraria
D. biauraria
D. triauraria
D. rufa
Successful parasitism (%)
L. japonica A. japonica
53
20
7
68
Not examined
L. japonica and A. japonica have wide host ranges
43
68
73
87
60
72
69
(Ref.: Mitsui & Kimura 2010; Kimura unpubl.)

Is it possible to control D. suzukii populations?
Probably difficult, because this species have
a high dispersal capacity. Even if a local
population is exterminated, migrants would
soon establish a new population.

acknowledgements
• Alberto Grassi, Omar Rota Stabelli, Alessandro
Cini, Matteo Graiff, Santosh Revadi, Monica
Sofia (FEM)
• Francesca Eccher and Patrizia Sacchetti (Univ.
Firenze)
• Augusto Loni, Andrea Lucchi and Alfio Raspi
(Univ. Pisa)

Research Fellowship to support a PhD student :
“Evolutionary Evolutionary genomics of fruit pests: Drosophila
suzukii and other grapevine parasites” parasites
We are seeking an highly motivated and independent postgraduate
student that will employ genomics and phylogeny to understand the
molecular basis of behavioural innovation. Model of study will be for
the most part the complete genome of Drosophila suzukii.
Please read the profile details to understand if you are eligible for the
position. In order to apply send your cv and fill the application form, also
available in the download area at
http://www.iasma.it/CRI_lavora_con_noi or cri.fmach.eu/education
Send your CV and application form to: phd.fem@iasma.it
Deadline for application: 10th January 2012.