HERE
56-28
CROSSING EXPERIMENTS WITH
PHILAENUS SPUMARIUS (HOMOPTERA)
By
0.
HALKKA, LllSA HEINONEN,
M.
RAATIKAINEN
and
A
R
J
A VAS
-4
R A1 N
E
N
DEPARTMENT
OF
GENETICS,
UNIVERSITY
OF
HELSINKI,
AND
DEPARTMENT
OF
PEST
INVESTIGATION,
AGRICULTURAL
RESEARCH
CENTRE,
TIKKURILA,
FINLAND
(Recei ed Sep embe
lG h,
1966)
INTRODUCTION
OLYMORPHISM
in ield popula ions o
Philaenus spuma ius
has
P
been s udied by a numbe o au ho s, and he equencies o he
di e en colou o ms ha e been epo ed in abou 20 publica ions.
Al hough, om esul s ob ained wi h na u al popula ions, i has been
in e ed ha he colou polymo phism is genically de e mined, c ucial
p oo om c ossing expe imen s has been wan ing. In he
USA,
C.
R.
WEAVER
has succeeded
in
ob aining o sp ing om known emales wi h
unknown ma ing pa ne s, and has ound ha he o ms end o e-
p oduce hemsel es (see
OWEN
and
WIEGERT,
1962). Simila expe i-
men s we e pe o med by he p esen au ho s in he au umn o 1964.
In hese expe imen s, emales ep esen ing he colou o ms
ma ginella
and
leucoph halma
we e ound
o
p oduce among hei o sp ing daugh-
e s like hei mo he , in addi ion o males and emales belonging o he
colou o m
ypica.
Pic u es o he colou o ms as dis inguished by us,
ha e been published by
HALKKA
(1964).
Ma e ial and me hods
All he emales and mos o he males used o c osses we e isola ed
as la ae. The isola ion wo k was done in he o es and ga den a ea
su ounding he "Nu mija i
A"
ield, which ha bou s one
o
he na u al
popula ions s udied by he senio au ho
(HALKKA,
1964). The o hy
spi le masses p oduced by he la ae usually con ained a single speci-
men only. Al oge he , 49 species o plan s we e used as ood sou ces by
Philaenus
la ae in he Nu mija i a ea.
A
de ailed epo on he dis i-
CROSSING EXPERIMENTS WITH PHILAENUS
307
bu ion o he di e en colou o ms on hese plan s will be published
elsewhe e. He e i will su ice o say ha he dis ibu ion appea s o be
pe ec ly andom.
In July
1965, 60
pai s we e placed in cages con aining po ed
T i o-
lium p a ense
(“Tammis o” p oduc ) and
A ena sa iua
(Swedish “Sol”).
The clo e was in ended o se e as ood, he oa s mainly as
a
si e o
o iposi ion. The lowe po s we e sunk in o he soil up o he im, he
lowe pa o he nylon cage ne su ounding he po . Apa om oc-
casional wa e ing, he cages we e un ended, un il
15
o hem we e
mo ed in o a g eenhouse on Decembe
31, 1965,
and he emaining
45
on Feb ua y
26, 1966.
The cages we e main ained a he Ag icul u al
Resea ch Cen e.
The win e o
1965-1966
was unusually se e e in Finland. A Tik-
ku ila, he mean empe a u es o Janua y and Feb ua y we e
-
13.9’
C
and
-
13.5O
C,
espec i ely. The cages, howe e , we e ai ly well
p o-
ec ed by abou
110
cm o snow on he g ound. In he g eenhouse,
a
empe a u e ange be ween
18
and
25
deg ees cen ig ade was main-
ained and humidi y was kep a ound
75
%.
High humidi y is essen ial
o
success ul ea ing o
Philaenus.
O he
60
pai s,
24
p oduced a leas one o sp ing, while
36
we e
ailu es. Mos o he ailu es we e no due o inabili y o
Phi aenus
eggs
o hibe na e bu o high la al mo ali y esul ing om poo hibe na-
ion o he
T i olium
used as ood plan . Spi le masses we e obse ed
in many o he cages which la e ailed o p oduce adul s.
A
o al o
234
F,
o sp ing we e ob ained,
118
emales and
116
males.
RESULTS
The c osses, oge he wi h hei
F,
o sp ing, a e epo ed in Table
1.
The o m
ilinea a
is a e a Nu mija i, and he isola ions did no
p oduce enough males belonging o his o m. In ac , all he
i inea a
male pa en s o he success ul c osses o igina ed om ield collec ions.
The
ypica
and
populi
males and he di e en emale o ms we e
isola ed om al oge he
12
species o ood plan s. A he ime
o
isola-
ion, he male and emale pa en s o c osses
9, 41, 57
and
59
we e li ing
oge he as la ae in a common spi le mass. In Table
1
and in he ol-
lowing epo , he c osses a e g ouped in o h ee sec ions acco ding o
he o m o he male pa en :
308
HALKKA, HEINONEN, RAATIKAINEN AND VASARAINEN
(1)
Wi h ypica
CIS
he male pa en :
In c osses
9
and
57
he emale, oo, belonged o
ypica,
and in bo h
cases bo h pa en s we e isola ed om he same spi le mass. Only
ypica
o sp ing we e p oduced.
In
c osses
5, 23
and
59
he emale belonged o
ilinea a.
The pooled
esul o hese c osses is
18
ilinea a
and
16
ypica
specimens.
In c osses
1
and
30,
he emale belonged o
ma ginella.
In addi ion o
ma ginella
and
ypica
specimens, c oss
30
includes in he
F,
gene a ion
ou
leucoph halma
emales, wo o which bea small whi e spo s on
hei ely ae and may be e be assigned o he o m
albomacula a.
The
male pa en o his c oss ob iously bo e
a
gene esponsible o he
leucoph halma
pheno ype in one o his ch omosomes, al hough his
gene was no exp essed in his pheno ype. The wo
albomacula a
speci-
mens may ha e esul ed om a ia ion in he exp essi i y o his gene
in he emale sex. I his explana ion
is
co ec , c osses
1
and
30
demon-
s a e he exis ence o wo majo genes, which a e he e p o isionally
named
ma
and
lop.
C oss
32,
wi h
la e alis
as
he emale pa en , p oduced a emale like
he mo he and
a
male like his a he .
In c osses
27
and
50,
he emale belonged o
lauicollis.
Al oge he
17
F,
o sp ing we e ob ained, all
ypica.
The ailu e o hese c osses o
p oduce
la icollis
may be due o chance, since only
7
emales we e
ound in he
F,
o
he wo c osses combined.
In c oss
31,
he emale belonged o
leucocephala.
Two emales, one
o hodox
leucocephala
and one wi h wo small whi e spo s on bo h
ely ae, we e ob ained. This la e specimen di e s om
a
ue
laui-
collis
pheno ypically and is bes in e p e ed as esul ing om a ia ion
in he exp essi i y o a majo gene esponsible o he
leucocephala
pheno ype. This gene is he e p o isionally named
Ice.
In c osses
20, 25
and
41,
he emale belonged o
leucoph halma.
Only
leucoph halma
and
ypica
o sp ing we e ound in he
F,
gene a ion.
The gene esponsible o he o ally black
leucoph halma
pheno ype
is
ob iously exp essed only in he emale sex, a esul indica ed by he
combined in o ma ion om c osses
30, 20, 25
and
41.
I he
lop
gene
eally
is
sex-con olled, he black males encoun e ed p inia ily in no h-
e n Finland ha e
a
di e en geno ype. I
is,
o cou se, also possible ha
he same gene is sex-con olled only in some pa s o i s dis ibu ion
a ea.
CROSSING EXPERIMENTS WITH PHILAENUS
309
TABLE
1.
The esul s
o
c osses be ween Philaenus colou o ms.
i
2
yp
2
-
i
7
yp
6
~-
C oss
no.
i
3
i
2
i
4
yp
8
i
3
yp
1
la
3
i
2
yp
2
i
2
yp
1
Female Male
pa en pa en
i
1
yp
2
i
6
yp
1
i
1
yp
1
To al
F,
o sp ing
3
44
9
57
Y
P
i
Y
P
i
Y
P
ma YP
i
1
yp
ma
I
YP
_____
7
2
25
5
23
59
1
30
32
1
14
2
8
9
27
50
31
YP
2
YP
5
Ice
1
“ la”
1
I-
2
1
1
11
3
20
25
41
-
lop
1
lop
5
yp
1
YP
5
1
YP1
-
YP
I
POP
yp
I
i
i
I
i
YP
2
1
YP
1
yp
4
i
3
I
yp
2
i
5
7
54 14
48
i
2
yp
1
1
i
3
yp
1
39
40
ma
1
-
i
3
yp
1
I
YP
1
ma
~~
la
Ila i
la
1
i
la i
]a
3
i
7
yp
7
I
i
4
yp
6
la
2
i
8
i
2
yp
9
27
21
47
49
19
44
46
7
14
5
234
24
118
I
116
(2)
Wi h populi as he mule pa en :
The o sp ing om he single c oss (c oss numbe
7)
wi h
populi
as
he male pa en and
ypica
as
he emale con ained only
ypica
speci-
mens.
(3)
Wi h ilinea a as he male pa en :
C oss
54,
wi h
ypica
as
he emale pa en ,
is
ecip ocal o c osses
5,
23 and
59.
Again,
as
in hese c osses,
ypica
and
ilinea a
pheno ypes
a e equally common in bo h males and emales. This ac p o es, ha
i
is an au osomal gene, since
Philaenus
males a e
XO
as
ega ds sex
de e mina ion. The combined in o ma ion om c osses
5,
23,
59,
54
and
310
HALPKA. HEINONEN, RAATIKAINEN AND VASARAINEN
48
shows, ha he
i
gene is dominan in bo h sexes. In c oss
48,
ilinea a
pa en s p oduced bo h
ilinea a
and
ypica
o sp ing.
The o sp ing o c osses
39
and
40,
be ween
a
ma ginella
emale and
a
ilinea a
male, shows he ecessi eness o he ypica condi ion
o-
wa ds he e ec o he
ma
and
i
genes.
The wo c osses,
47
and
49,
bo h p oduced equen o sp ing, includ-
ing, in addi ion o he pa en al ypes
la e alis
and
ilinea a,
a numbe
o
ypica
specimens. The o sp ing om c osses
47
and
49,
oge he wi h
he esul o c oss
32,
p o e he exis ence o a gene,
la ,
esponsible o
he
la e alis
pheno ype.
C osses
19,
44
and
46
all p oduced
ilinea a
(pa e nal pheno ype)
and
ypica
emales and males. The ma e nal pheno ype
la icollis
was
ob ained in c oss
44
only. The exis ence o a gene o his pheno ype,
la,
seems unques ionable, bu ei he he gene in ques ion has a low
pene ance
o
he
la icollis
pheno ype may also be caused by he ac ion
o o he genes.
DISCUSSION
The esul s o he c osses desc ibed abo e show con incingly ha
each o he dis inc ly colou ed and eadily dis inguished pheno ypes is
de e mined by a pa icula majo gene. Mos
o
he genes a e egula ly
exp essed in he emales bu p ac ically ne e in he males. This is ue
o he exp ession o he majo genes
ma ,
la ,
Ice
and
lop.
The
i
gene,
in con as , is exp essed in bo h sexes.
A
i h sex-con olled gene, he
exp ession o which is con ined o he emale sex,
la,
also exis s. How-
e e , he dependence
o
he
la icollis
pheno ype on he p esence o he
la
gene
is
pe haps no
so
clea -cu as in he case o he o he ou genes
and hei espec i e pheno ypes.
Samples collec ed om he ield e eal he ex eme a iabili y and
ob ious he e ogenei y o he basic colou o m,
ypica.
Ob iously
a
g ea numbe o modi ying colou genes, he e ec
o
some o which is
p obably u he modi iable by ex e nal ac o s, combine o c ea e he
long a ay o pheno ypes om uni o mly ligh o uni o mly da k o ms.
Many o hese modi ying genes a e no allelomo phs o he majo colou
pa e n genes. Al hough i is likely ha he
i, ma , la , la, Ice
and
lop
genes a e allelomo phs
o
closely linked loci, and ha hey a e all au o-
somal, e en his has
no
been conclusi ely es ablished.
Fo
his eason,
neu al and noncommi al symbols o hese loci
o
genes a e used
h oughou his pape .

CROSSING EXPERIMENTS WITH PHILAENUS
311
P o ided ha he pene ance o he colou genes is comple e, he
dominance o he
i, ma , la , la, Ice
and
lop
genes makes es ima ion
o 2pq equencies ai ly easy in popula ions in which he pheno ypes
a e sha ply dema ca ed.
Fo
hese genes, he 2pq equencies a y be-
ween
1
%
and
7
%
in mos popula ions in Finland. The homozygo es
hus con ibu e insigni ican ly o he gene equencies in hese popula-
ions. A he p esen phase o gene ical wo k on
Philaenus
i is no
known whe he some o he genes a e possibly le hal when homozygous.
We
also
know no hing o he o de o dominance
o
epis asis in his
a ay o colou genes. The expe imen al p og am o ob aining
F,
is
being ex ended by
us
and s eps o p oducing
Fa
ha e been aken.
In many espec s, colou polymo phism in
Philaenus
a o ds an
in e es ing compa ison wi h wha is known o balanced polymo phisms
in he Lepidop e a. As wi h he bu e lies, polymo phism in he
meadow spi lebug is la gely sex-con olled. I seems ha many o he
ules go e ning polymo phism in he Lepidop e a may also be alid in
his Homop e an. A e a long pe iod o pe sis en and pains aking
wo k, bo h he gene ics and ecology o ce ain bu e lies a e now being
in es iga ed a a a he ad anced s age (e.6.
SHEPPARD,
1961).
Wi h
Philaenus,
ecological wo k synch onized and pa allel wi h gene ic anal-
ysis has been ba ely begun by
us.
Philaenus
a o ds a ou able ma e ial
o s udies on sex-con olled inhe i ance and also o in es iga ions on
he e olu ion o dominance.'
Acknowledgemen s.
-
The English o he manusc ip was checked by
M s.
JEAN
MARGARET
PERTTUNEN,
M.A.,
o whom ou since e hanks a e due. G an s o he
s udy ha e been ecei ed om he Uni e si y o Helsinki and om he Na ional
Resea ch Council o Sciences.
SUMMARY
The mode o inhe i ance o he di e en genes de e mining he coIou
o ms o
Philaenus spuma ius
was s udied a he
F,
gene a ion le el.
Six majo genes, each one esponsible o
a
dis inc colou pa e n,
we e obse ed in his wo k. In
a
single dose, i e o hese genes, he e
p o isionally named
ma , la , la,
Ice
and
lop,
always mani es hei
'
No e added
in
p oo :
The i s adul specimens belonging o he
Fa
gene a ion
eme ged in No embe
1966.
They show dominan ansmission o he genes
i
and
lop
and s eng hen he iew ha
in
he emales
yp
is
he bo om ecessi e in a
dominance hie a chy se ies.
A
de ailed accoun o he
F,
p ogeny will be published
in ano he con ex .
312
HALEKA, HEINONEN. RAATIEAINEN AND VASARAINEN
e ec s in he emales bu ne e in he males. The six h gene,
i,
has
a
dominan mode
o
inhe i ance in bo h sexes.
The
la icollis
pheno ype may pe haps ha e h ee al e na i e gene ic
backg ounds: a) he
la
gene, b) ac ion
o
da kening modi ie s on he
ypica
gene ic condi ion and c) ac ion o genes nonallelic wi h
lu
o
Ice
and epis a ically causing he appea ance o wo whi e spo s on bo h
ely ae o an indi idual wi h a
Ice
gene in he geno ype.
The six majo genes may be allelomo phic wi h each o he .
The exp essi i y o he six majo genes is ema kably independen
o
ex e nal ac o s, including ood plan s
o
he
P
and
F,
gene a ions.
The possibiIi y ha he six majo genes cons i u e a dominance
hie a chy
is
being u he s udied, oge he wi h he ecologicd aspec s
o he sex-con olled inhe i ance o he colou genes.
Li e a u e ci ed
IIALKKA,
0.
1964. Geog aphical, spa ial and empo al a iabili y in he balanced poly-
OWEN,
D.
F.
and WIEGERT,
R.
G.
1962. Balanced polymo phism in he meadow
SHEPPARD, P.
M.
1961. Recen gene ical
wo k
on polymo phic mime ic Papilios.
-
mo phism
o
Philaenus spuma ius.
-
He edi y
19:
383-401.
spi lebug, Philaenus spuma ius.
-
Ame . Na .
96:
353-359.
Symp. Royal En om.
SOC.
London
I:
20-29.