Symbiont-Supplemented

Current Biology 24, 2465–2470, October 20, 2014 ª2014 Elsevier Ltd All rights reserved http://dx.doi.org/10.1016/j.cub.2014.08.065

Report

Maternal Investment UnderpinningHost’s Ecological Adaptation

Nahomi Kaiwa,1,2,5 Takahiro Hosokawa,1,5 Naruo Nikoh,3

Masahiko Tanahashi,1 Minoru Moriyama,1 Xian-Ying Meng,1

Taro Maeda,4 Katsushi Yamaguchi,4 Shuji Shigenobu,4

Motomi Ito,2 and Takema Fukatsu1,*1National Institute of Advanced Industrial Science andTechnology (AIST), Tsukuba 305-8566, Japan2Department of General Systems Studies, Graduate School ofArts and Science, the University of Tokyo, Tokyo 153-8902,Japan3Department of Liberal Arts, the Open University of Japan,Chiba 261-8586, Japan4National Institute for Basic Biology, Okazaki 444-8585, Japan

Summary

Maternal investment for offspring’s growth and survival is

widespread among diverse organisms [1–3]. Vertical sym-biont transmission via maternal passage is also pivotal for

offspring’s growth and survival in many organisms [4–6].Hence, it is expected that vertical symbiont transmission

may coevolve with various organismal traits concerningmaternal investment in offspring. Here we report a novel

phenotypic syndrome entailing morphological, histological,behavioral, and ecological specializations for maternal in-

vestment and vertical symbiont transmission in stinkbugsof the family Urostylididae [7–9]. Adult females develop

huge ovaries exaggerated for polysaccharide excretion, pos-

sess novel ovipositor-associated organs for vertical trans-mission of a bacterial symbiont (‘‘Candidatus Tachikawaea

gelatinosa’’), and lay eggs covered with voluminous symbi-ont-supplemented jelly. Newborns hatch in midwinter, feed

solely on the jelly, acquire the symbiont, and grow duringwinter. In spring, the insects start feeding on plant sap,

wherein the symbiont localizes to a specializedmidgut regionand supplies essential amino acids deficient in the host’s

diet. The reduced symbiont genome and host-symbiont co-speciation indicate their obligate association over evolu-

tionary time. Experimental deprivation of the jelly results innymphal mortality, whereas restoration of the jelly leads to

recovered nymphal growth, confirming that the jelly supportsnymphal growth in winter. Chemical analyses demonstrate

that the galactan-based jelly contains a sufficient quantityof amino acids to sustain nymphal growth to the third instar.

The versatile biological rolesof the symbiont-containing egg-covering jelly highlight intricate evolutionary interactions be-

tween maternal resource investment and vertical symbionttransmission, which are commonly important for offspring’s

growth, survival, and ecological adaptation.

Results and Discussion

Peculiar Reproductive Ecology of Urostylidid Stinkbugs

Stinkbugs of the family Urostylididae (Insecta: Hemiptera)embrace over 7 genera and 80 species in Southern and

5Co-first author

*Correspondence: t-fukatsu@aist.go.jp

Eastern Asia [7] and five species representing 2 genera inJapan [8] (see Table S1 available online). Except for severaltaxonomic and systematic works [9–11], general biological as-pects of urostylidid stinkbugs have been poorly documented[7, 12–14]. We observed the life cycle of Urostylis westwoodiiand Urostylis annulicornis in Tsukuba, Ibaraki, Japan from2008 to 2013. Adult insects (Figure 1A) were found on treesofQuercus acutissima andQuercus serrata from early summerto winter. In late autumn around November, reproductivelymature females with conspicuously enlarged abdomen ap-peared and laid egg masses on the bark of the host tree trunk(Figure 1B). The eggmasseswere quite strange in appearance:oval eggs arranged in two rows are entirely embedded in acopious amount of jelly-like substance (Figures 1B and C),with three thin club-shaped white projections protrudingfrom each of the eggs through the jelly layer (Figures 1C andD), which are presumably aeromicropyles for breathing. Strik-ingly, the eggs hatched toward the end of winter around lateFebruary. At that time, the climate was still so cold that neitherbuds nor leaves of the host plants were available, and newbornnymphs immediately fed on the jelly (Figure 1E). The nymphsstayed together on the egg mass, exclusively lived on the jelly,and grew to the third instar within a month or so (Figure 1F).Then, the third-instar nymphs dispersed from late March toearly April when the host trees started shooting buds.

Egg-Covering Jelly Contains Symbiotic Bacteria

DNA staining revealed numerous DNA-positive particles withinthe egg-covering jelly (Figures 2A and B). PCR, cloning,sequencing, and phylogenetic analysis of bacterial genes iden-tified two bacterial symbionts. A distinct gammaproteobacte-rial lineage, whose 16S rRNA gene exhibited the highestBLAST hit to the midgut symbiont Rosenkranzia of the acan-thosomatid stinkbug Elasmucha putoni (90.5% [1,360/1,502]identity; accession number AB368828), was clustered withthe obligate midgut symbionts Rosenkranzia and Ishikawaellaof acanthosomatid andplataspid stinkbugs, aswell as the obli-gate endosymbiont Buchnera of aphids (Figures S1A–S1C;hereafter called midgut symbiont). Another gammaproteobac-terial lineage, whose 16S rRNA gene exhibited the highestBLAST hit to the Sodalis symbiont of the scutellerid stinkbugCantao ocellatus (99.4% [1,456/1,464] identity; accessionnumber AB541010), was closely related to Sodalis glossinidiusof tsetse flies and Sodalis-allied symbionts of other insects(Figure S1A; hereafter called Sodalis symbiont). In situ hybrid-ization identified the DNA-positive particles within the jelly asbacterial aggregates consisting of the midgut symbiont cellsand the Sodalis symbiont cells (Figure 2C). Diagnostic PCRoffiveurostylidid species (in total 138 individuals)detectedper-fect infections (consistently 100%) with themidgut symbiont incontrast to imperfect infections (ranging from 60% to 100%)with the Sodalis symbiont (Table S2). The midgut symbiont ex-hibited host-symbiont cospeciation (Figures S2A and S2B) anddrastic genome reduction (down to 0.7Mb in size) (FigureS2C).These results strongly suggest that the midgut symbiont hasbeen an obligate partner for the urostylidid stinkbugs overevolutionary time, whereas the Sodalis symbiont is probably afacultative associate for them. It should be noted, however,

1 mm

1 mm

5 mm

1 cm

0.5 mm

3 mm

C

B

A

D

FE

1 mm1 mm 1 mm

M1

M2 M3

M45 mm

YO

IO

MOGE

M4M4

YO

2 mm

5 mm

5 mm

JIH

G

M

KL

Figure 1. Reproductive Ecology, Anatomy, and

Behavior of Urostylidid Stinkbugs

(A) An adult female with swollen abdomen (left)

mating with an adult male (right).

(B) An adult female laying an egg mass covered

with jelly-like substance.

(C) An enlarged image of an egg mass, wherein

breathing tubes (arrowheads) are protruding

from each egg through the jelly layer.

(D) An enlarged image of isolated eggs with three

breathing tubes (arrowheads) on a tip.

(E) First-instar nymphs feeding the jelly on an egg

mass.

(F) Third-instar nymphs on an egg mass, wherein

the jelly has been mostly consumed.

(G) Dissected abdomen of a reproductivelymature

adult female. A left half of ovary consisting of

seven ovarioles, a stretch of eviscerated midgut,

and a pair of yellow organs associated with genital

chamber are seen. Abbreviations are as follows:

GE, germarium; IO, immature oocyte; M1, midgut

first section; M2, midgut second section; M3,

midgut third section; M4, midgut fourth section

with crypts; MO, mature oocyte; YO, yellow organ.

(H) The anterior end of the midgut fourth section.

(I) The posterior end of the midgut fourth section.

(J) A dissected yellow organ.

(K) An adult female laying an egg mass on the

bottom of a Petri dish.

(L) An ovipositing adult female pickedwith fingers,

with an egg-jelly unit on the ovipositor.

(M) Egg-jelly units spread on the bottom of a Petri

dish. (A)–(F) and (K)–(M) are Urostylis westwoodii,

whereas (G)–(J) are Urostylis annulicornis.

Current Biology Vol 24 No 202466

that the Sodalis symbiont exhibits remarkably high infectionfrequencies in urostylidid stinkbugs, particularly in Urostylisspecies consistently at 100% (Table S2), which suggests thepossibility that the Sodalis symbiont may play, though notnecessarily essential, somebiological roles for thehost insects,as known for other facultative insect symbionts [15].

Specialized Anatomical Traits for Jelly Production and

Symbiont TransmissionThe swollen abdomen of the mature females was filled with anextremely developed ovary with a pair of seven ovarioles oneach side. In the basal half of each ovariole, voluminous trans-lucent liquid embedding mature oocytes was seen (Figure 1G),indicating the location of jelly production and storage. Mean-while, diagnostic PCR of dissected ovaries detected nomidgutsymbiont (Table S3), suggesting that its supplementation tothe jelly occurs not transovarially but upon or after oviposition.As in other stinkbugs, the midgut of the urostylidid stinkbugswas differentiated into morphologically distinct regions (Fig-ure 1G), of which the midgut fourth section constituted a sym-biotic organ, equipped with a number of crypts and harboringthe symbiotic bacteria therein (Figures S3A, S3B, S3E, andS3F). Oddly, the anterior and posterior ends of the midgutfourth section were constricted, forming a sausage-shapedisolated symbiotic organ (Figures 1H and 1I). Therefore, sym-biont supplementation via midgut-derived excretion, as ob-served in many stinkbugs [4, 16–18], is not possible for theurostylidid stinkbugs. Notably, we discovered a pair of peculiarfemale-specific organs, oval in shape and yellow in color, asso-ciatedwith the genital chamber (Figures 1G and 1J). The yelloworgan, consisting of glomerate white tubes and receiving richsupply of yellow tracheae, was densely populated by the sym-biotic bacteria within the tubes (Figures S3C, S3D, S3G, and

S3H). Probably, the symbiotic bacteria are supplementedfrom this organ to the egg-containing jelly from the ovaryduring oviposition. Similar, though anatomically distinct, fe-male-specific genital organs for vertical symbiont transmissionwere reported from acanthosomatid stinkbugs [19]. In both themidgut symbiotic organ and the yellow organ, themidgut sym-biont was overwhelmingly more abundant than the Sodalissymbiont (Figures S3B, S3D, S3E, and S3G). These peculiaranatomical traits of adult females were commonly found in allthe urostylidid species we examined.

Production of Egg-Jelly Complex and Jelly-MediatedVertical Symbiont Transmission

We collected reproductively mature adult females ofU. westwoodii with swollen abdomen, placed them in Petridishes individually, and observed their behavior under a videocamera. The females laid eggs in two rows on the substrata(Figure 1K), with each egg embedded in a packet of large jellymass (Figures 1L and 1M). Diagnostic PCR revealed that iso-lated eggs did not contain the midgut symbiont whereas allfirst-instar nymphs gathering on natural egg masses were in-fected (Table S3), suggesting vertical transmission of themidgut symbiont via jelly feeding. Meanwhile, consideringthat some of the dissected ovaries and the isolated eggswere Sodalis-positive (Tables S3), transovarial passage mayalso contribute to vertical transmission of theSodalis symbiont.Whole-mount in situ hybridization revealed that the ingestedsymbiotic bacteriawere immediately localized to a posterior in-testinal region in the first instar (Figure 2D), and establishedspecific infection in a morphologically-differentiatedmidgut re-gion by the second instar (Figure 2E). It is conceivable, althoughspeculative, that the anterior and posterior ends of the midgutregion are constricted off in the developmental course toward

Figure 2. Symbiont Localization in Egg-Covering Jelly and Symbiont Local-

ization to Nymphal Midgut in Urostylis annulicornis

(A) DNA staining of sectioned jelly with SYTOX Green. IR and UR indicate

central infected region and peripheral uninfected region of the jelly, respec-

tively. Numerous symbiont clusters are visualized in the infected region. The

strong signal is due to autofluorescence of a sectioned egg.

(B) A newborn nymph probing the jelly. An egg mass with hatchlings was

fixed in chilled acetone, sliced with razor at a position of nymphal feeding,

and stained with SYTOX Green.

(C) In situ hybridization of a symbiont cluster in the infected region, which

consists of the midgut symbiont cells (green) and the Sodalis symbiont cells

(red).

(D and E) Whole-mount in situ hybridization of a first-instar nymph (D) and a

second-instar nymph (E) targeting bacterial 16S rRNA, wherein a posterior

midgut region emits symbiont-derived fluorescence signals.

Symbiont-Supplemented Maternal Gift for Offspring2467

the adult stage, thereby forming the sausage-shaped isolatedsymbiotic organ (see Figures 1G–1I).

Midgut Symbiont Genome Streamlined for Provisioning

of Essential Amino AcidsWe determined a 708,439 bp circular genome of the midgutsymbiont of U. westwoodii (Figure 3A). General features ofthe reduced genome were similar to those of the obligate en-dosymbionts of other insects like Buchnera of aphids, Bloch-mannia of ants and Wigglesworthia of tsetse flies [20–22],and also to that of the obligate gut symbiont Ishikawaella ofplataspid stinkbugs [23]. While the midgut symbiont genome

retained many genes responsible for basic cellular processessuch as translation, replication, energy production, etc., di-verse metabolic pathways and structural elements such asTCA cycle, flagella, most of transporters, almost all of tran-scription factors, etc., have been lost from the genome (Fig-ure S2D). By contrast, many genes involved in metabolism ofamino acids were retained: the midgut symbiont is capableof synthesizing almost all essential amino acids (Figure 3B),some nonessential amino acids (Figure 3C), and also severalvitamins (Figure 3D). On the grounds that urostylidid stinkbugsfeed exclusively on host plant sap [8] and the plant sap isgenerally devoid of essential amino acids and some vitamins[6], the midgut symbiont probably compensates for the nutri-tional deficiency of the diet, as Buchnera does for the hostaphid [5, 6].

Essential Role of Nutritious Jelly for Nymphal Growth

and SurvivalIn the urostylidid stinkbugs, however, newborn nymphs appearin winter and thus have no chance to suck plant sap. Under thelow temperature in winter, the midgut symbiont may be unableto synthesize essential amino acids efficiently. Here it seemslikely that the egg-covering jelly plays a substantial biologicalrole. We experimentally investigated the effects of jelly feedingon nymphal growth of U. westwoodii by preparing controlegg masses without treatment (Figure 4A), jelly-removed eggmasses from which the jelly was carefully removed using ster-ilized toothpicks (Figure 4B), and jelly-restored egg massesonto which the removed jelly was placed back (Figure 4C).When these egg masses were monitored in the laboratory,egg hatching rates were consistently around 90% irrespectiveof the groups (Figure 4D), indicating no substantial damage bythe experimental treatments to the eggs. However, molting rateto the second instar in the jelly-removed egg masses, around20%, was significantly lower than that in the control eggmasses over 90% (Figure 4E), and, strikingly, no nymphsmolted to the third instar in the jelly-removed egg masses,which was in sharp contrast to over 60% molting to the thirdinstar in the control egg masses (Figure 4F). The second-instarnymphs from the jelly-removed egg masses were evidentlysmaller than those from the control eggmasses (Figure 4G), re-flecting little nymphal growth without jelly feeding. Thesenymphal defects were significantly recovered in the jelly-restored egg masses (Figures 4E and 4F). In the jelly-restoredegg masses, meanwhile, the experimentally manipulated jellyoften grewmold, and suchmold-contaminatedeggmasses ex-hibited low survival rates of the nymphs, which resulted in thelower molting rates in the jelly-restored eggmasses than thosein the control egg masses (Figures 4E and 4F). Although spec-ulative, these observations suggest the possibility that theouter jelly layer may have some antimicrobial activities. Thejelly collected from natural egg masses of U. westwoodii con-sisted of 60% water, 26% sugars, and 8% proteins (TableS4), indicating that the jelly is nutritionally carbon excess, whilea substantial amount of nitrogen is present. Sugar-compositionanalyses of the jelly revealed that, strikingly, galactose ac-counted for over 90% of total sugars, with small amounts ofmannose, glucose, glucuronic acid, and glucosamine (TableS4; Figure 4H). These results strongly suggest that the egg-covering jelly mainly consists of galactose-based polysaccha-rides, so-called galactans [24]. Production of galactan gels,such as agar, carrageenan, and pectin, in substantial quantitiesis commonly found in algae and plants, but seems exceptionalin animals [24]. Comparison of amino-acid compositions

ArgA ArgCArgB ArgD ArgE ArgF ArgG ArgHGlu Arg

LysC ThrAAsd ThrB ThrCAsp Thr

MetA MetCMetBMet

MetE

PyruvateIlvCIlvHI IlvD (Val)*

LeuA LeuBLeuCD (Leu)*LysC DapAAsd DapB DapD

LysAspArgD DapE DapF LysA

Erythrose-4P

AroF AroQAroB AroE AroK(Phe)*

AroA AroC PheA

TrpE TrpCTrpD TrpA TrpTrpB

ThrIlvA IlvCIlvHI IlvD (Ile)*

HisG HisAHisI HisFH HisB HisHisC HisB HisD5-phospho-ribosyl-1-

pyrophosphate

IlvE

IlvE

IlvE

IlvE

B

Candidatus

(midgut symbiont of Urostylis westwoodii)

708,439 bp(AP014521)

A

Translation

Transcription

Replication, recombination, repair

Cell cycle, cell division

Defense mechanisms

Signal transduction

Cell wall/membrane/envelope

Energy production and conversion

Carbohydrate metabolism

Amino acid metabolism

Nucleotide metabolism

Coenzyme metabolism

Lipid metabolism

Inorganic ion metabolism

Secondary metabolites metabolism

General function prediction only

Function unknown

No homologous ORFs

TyrBAroA AroC TyrA (Tyr)*AroF AroQAroBErythrose-4P

AroE AroK

Glu (Pro)ProB ProA ProC SerA SerC

(Asn)SerB3-phopho-

glycerate

Asp

Gly (Asp)Glu

Glu (Gln)AsnB GlnA

AspC

(Ser)

CysE CysKSer Cys

CysIscS

Gln GluGuaA etc.

GlyASer

Ala

C

BioCBiotin

Malonyl-CoA

BioF BioA BioD BioBBioH

FA synthesispathway

GTPRibFRibA RibBRibD RibE RibC

FAD

D

GTP (Folate)FolAFolP FolCFolKFolBFolE NudB

PabCPabAB

Pyridoxal 5PPdxJ PdxHPdxASerCPdxBGapAErythrose-

4P

Figure 3. Genome and Metabolic Pathways of Midgut Symbiont of Urostylis westwoodii

(A) Circular view of the midgut symbiont genome ofUrostylis westwoodii. On the GC skew circle, red and blue indicate G-rich and poor, respectively. On the

CDS circle, colors indicate functional categories as shown at the bottom.

(B–D) Biosynthetic pathways of essential amino acids (B), nonessential amino acids (C), and vitamins (D) retained in the symbiont genome. Parentheses

indicate that those synthetic pathways encoded in the symbiont genome are incomplete, whereas asterisks imply that the missing final step enzymes

(strikethrough) are probably complemented by corresponding enzymes of either the symbiont or the host insect origin [20, 23].

Current Biology Vol 24 No 202468

between the jelly, eggs, and third-instar nymphs ofU. westwoodii revealed that (1) both essential and nonessentialamino acids are present in the jelly in a balanced manner, (2)amino-acid composition of the jelly is similar to those of theeggs (Pearson’s correlation coefficient r = 0.919) and thethird-instar nymphs (r = 0.903), (3) the quantity of amino acidscontained in the jelly per capita plus an egg is almost equalto or more than the quantity of amino acids constituting athird-instar nymph, and therefore (4) the jelly contains a suffi-cient amount of nutrients for nymphal growth to the third instar(Figures 4I and 4J). Here, these amino acids may exist as eitherfree amino acids or proteins in the jelly or as proteins consti-tuting the symbiont cells embedded in the jelly. Note that thestrong symbiont signals within the posterior midgut in the firstinstar diminished toward the second instar (Figures 2D and 2E),indicating that the majority of the symbiont cells ingested withthe jelly are not maintained but consumed by the nymphs. It isalso of interest whether the midgut of urostylidid nymphs ex-hibits galactan-degrading activities.

Versatile Biological Functions of Egg-Covering Jelly

in Urostylidid StinkbugsOn the basis of these results, we propose the following biolog-ical roles of the egg-covering jelly for the urostylidid stinkbugs:(1) protecting eggs against environmental stresses such as

desiccation and microbial contamination, (2) providing thesole food source for newborn nymphs, (3) supporting nymphalgrowth and survival to the third instar, (4) thereby enablingnymphal growth and survival in the winter season, and also(5) ensuring survival of the symbiotic bacteria outside thehost body as long as for several months, and (6) therebyensuring vertical transmission of the symbiotic bacteria viahost’s jelly feeding. Egg hatching and nymphal growth inwinterare exceptional among stinkbugs and other insects [25, 26].The peculiar phenology of the urostylidid stinkbugs, whichmust be relevant to the evolution of the egg-covering gelati-nous biopolymer, seems to confer such fitness advantagesas escape from natural enemies that are inactive in winter,and prompt utilization of host plant shoots of high nutritionalquality in early spring by already-grown nymphal insects.

Conclusions and Perspectives

Moms take care of their babies. So do females of many verte-brates and invertebrates. Maternal investment in offspring iswidespread among diverse animals [1–3]. Not only in insectsand other invertebrates but also in vertebrates including hu-mans, microbial symbionts residing in the gut or elsewhere,whose vertical transmission usually occurs via maternal pas-sage, substantially contribute to survival and fitness of theirhosts [27, 28]. Our findings in the urostylidid stinkbugs provide

Control

Jelly- removed

Control Jelly-removed Jelly-restored

0 20 40 60 80

100

Control Jelly removed

Jelly restored

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100

Control Jelly removed

Jelly restored

0 20 40 60 80

100

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Jelly restored 1 mm

2 mm2 mm 2 mm

a

b

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a

b

cn.s.

Egg hatching rate

B CA

D E(%)(%)

Molting rate to 2nd instar

(%)

Molting rate to 3rd instarF G

Inte

nsity

(x

108

cps)

10 11 12 13 14 15 16 17 18 19 20Time (min)

Hexoses: m/z = 511

Uronic acids: m/z = 525

Hexosamines: m/z = 510

Pentoses: m/z = 493

Gal

Man

H

0.0

1.0

1.5

2.0

2.5

0.5

2

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14I

Lys His Thr Val Leu Ile Phe Met Trp

JellyEgg3rd nymphJelly + Egg

Essential amino acids

3

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12

21

18

JNon-essential amino acids

Pro Ala Glx Asx Gly Ser Arg Tyr Cys

24

JellyEgg3rd nymphJelly + Egg

Figure 4. Functional and Nutritional Analyses of Egg-Covering Jelly of Urostylis westwoodii

(A) A control egg mass.

(B) A jelly-removed egg mass.

(C) A jelly-restored egg mass, where the removed jelly was placed back onto the eggs.

(D–F) Comparisons of egg hatching rates (D), molting rates to the second-instar (E), andmolting rates to the third-instar (F) between the control eggmasses,

the jelly-removed egg masses and the jelly-restored egg masses. Means and SD are shown (n = 10, respectively). Different alphabets indicate statistically

significant differences (likelihood ratio test; p < 0.05).

(G) Second-instar nymphs of the same age from a control egg mass and a jelly-removed egg mass.

(H) Sugar analysis of the hydrolyzed jelly by LC/MS. Chromatographs of selected ion mass of sugars derivatized with phenyl-methyl-pyrazolone are shown.

Gal and Man indicate peaks of galactose and mannose, respectively.

(I and J) Comparison of essential amino acids (I) and nonessential amino acids (J) contained in the jelly per capita, an egg, and a third-instar nymph. Means

and SD are indicated (n = 7 or 8).

Symbiont-Supplemented Maternal Gift for Offspring2469

general and novel insights into potential relevance of symbio-sis to evolutionary, ecological, physiological, morphological,and genomic traits of adaptive importance in diverse animals.

Proposal of Candidate NameBased on the distinct and coherent microbiological, phyloge-netic, and evolutionary traits described in this study, we pro-pose the designation ‘‘Candidatus Tachikawaea gelatinosa’’for the midgut symbiont clade associated with the stinkbugsof the family Urostylididae. The type strain is from Urostyliswestwoodii collected at Tsukuba, Japan (accession numbers:complete genome AP014521; 16S rRNA AB758419; groELAB758363; gyrB AB758380), and other strains are detectedfrom Urostylis annulicornis, Urostylis striicornis, Urochelaquadrinotata, and Urochela luteovacia (see Table S1). Thegeneric name honors a Japanese entomologist Shuji Tachi-kawa, who has significantly contributed to systematics andecology of stinkbugs in Japan including urostylidids [8]. The

specific name refers to the egg-covering jelly typical of the ur-ostylidid stinkbugs that contains the symbiont for verticaltransmission to the offspring.

Accession Numbers

The DNA Data Bank of Japan accession numbers of nucleotide sequences

reported in this study are as follows: DRA001205, AP014521, AB823739,

AB758358-AB758431, AB821277-AB821290, and AB858363-AB858383.

Supplemental Information

Supplemental Information includes three figures, four tables, and Supple-

mental Experimental Procedures and can be found with this article online

at http://dx.doi.org/10.1016/j.cub.2014.08.065.

Acknowledgments

We thank Y. Gyotoku, E. Hara, A. Kikuchi, T. Ohbayashi, M. Sakakibara, M.

Takai, and H. Toju for insect samples; J. Makino, W. Kikuchi, and K. Nikoh

Current Biology Vol 24 No 202470

for technical and secretarial assistance; S. Hanada for bacterial nomencla-

ture, J.P. McCutcheon for comments on the manuscript; and Y. Kamagata

for logistic support. This studywas supported by the Program for Promotion

of Basic and Applied Researches for Innovations in Bio-oriented Industry to

T.F. and N.N. and by the JSPS KAKENHI grant (22128001, 22128007, and

25221107) to T.F., N.N., and S.S. The JSPS Fellowship for Young Scientists

supported N.K. and M.M.

Received: August 4, 2014

Revised: August 28, 2014

Accepted: August 29, 2014

Published: September 25, 2014

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