Feminization Of Genetic Males Research Articles

Evidence for feminized genetic males in a flea beetle using newly identified X-linked markers.

The equilibrium of sex ratios in sexually reproducing species is often disrupted by various environmental and genetic factors, including endosymbionts like Wolbachia. In this study, we explore the highly female-biased sex ratio observed in the flea beetle, Altica lythri, and its underlying mechanisms. Ancient hybridization events between Altica species have led to mitochondrial DNA introgression, resulting in distinct mitochondrial haplotypes that go along with different Wolbachia infections (HT1-wLytA1, HT1*- uninfected, HT2-wLytA2, and HT3-wLytB). Notably, beetles with some haplotypes exclusively produce female offspring, suggesting potential Wolbachia-induced phenomena such as feminization of genetic males. However, the observed female bias could also be a consequence of the ancient hybridization resulting in nuclear-cytoplasmic conflicts between introgressed mtDNA and nuclear genes. Through transcriptomic analysis and the program SEX-DETector, we established markers for genotypic sex differentiation for A. lythri, enabling genetic sexing via qPCR. Our findings suggest that feminization of genetic males is contributing to the skewed sex ratios, highlighting the intricate dynamics of sex determination and reproductive strategies in this flea beetle. This study provides valuable insights into the dynamics of genetic conflicts, endosymbionts, and sex ratios, revealing the novel phenomenon of genetic male feminization in the flea beetle A. lythri.

Wolbachia: It’s Role In Pest Management

Wolbachia is a microorganism that infects and replicates inside host cells and is mainly present in reproductive tissues of animals withjoint feet and roundworms. In arthropods, it is found in insects, mites, spiders, terrestrial isopods, springtails etc. A survey that wasrecently conducted showed that Wolbachia is present in above 65% of insect species making this microorganism as one of the mostintracellular bacterial genus so far discovered. Wolbachia controls their hosts’ reproduction through unique mechanisms that incorporatecytoplasmic incompatibility (CI), parthenogenesis induction (PI), male-killing and feminization of genetic males. Recently, this bacteriahas been used as a bio-control agent for controlling insect pests. Different arthropods which were laboratory-reared and field-collected,have been screened against this bacteria to see whether this bacteria can be used as a bio-control agent

Investigating the frequency of Wolbachia infection in West Virginia arthropods.

Wolbachia is an intracellular bacterial symbiont that infects the reproductive tissue of Arthropods, particularly insects. Wolbachia is transmitted primarily through the ova cytoplasm, and alters reproduction of their host. Wolbachia have been linked with male killing, feminization of genetic males, parthenogenesis, and most often with cytoplasmic incompatibility. Due to these effects on reproductive success, Wolbachia is a suspected driver of evolution and speciation in arthropods. Investigations of the frequency of infection in insects around the world suggest that an equilibrium has been reached with infection rates ranging from 20% to 65%. We are investigating the infection rate with Wolbachia in arthropods in central West Virginia to determine the frequency of infection in this area. Insects were collected in the summer and fall of 2015 from wooded and meadow areas of the Campus of Glenville State College, as well as in Lewis County in the area surrounding Stonewall Jackson Lake, and fixed in 95% ethanol. To date, 193 of the 284+ collected insects, have been identified to species. DNA is being extracted from the identified species, and infection determined by using the polymerase chain reaction (PCR) using Wolbachia specific primers. To date, 36 of 73 insects tested have been demonstrated to have Wolbachia infection. To get a clear understanding of the percent of infection in this area, more insects must be collected and sampled. Determining the infection frequency by Wolbachia is an important first step in understanding the impact of these bacteria on insect evolution and speciation in West Virginia.

Feminization of the Isopod Cylisticus convexus after Transinfection of the wVulC Wolbachia Strain of Armadillidium vulgare.

Reproductive parasites such as Wolbachia are able to manipulate the reproduction of their hosts by inducing parthenogenesis, male-killing, cytoplasmic incompatibility or feminization of genetic males. Despite extensive studies, no underlying molecular mechanism has been described to date. The goal of this study was to establish a system with a single Wolbachia strain that feminizes two different isopod species to enable comparative analyses aimed at elucidating the genetic basis of feminization. It was previously suggested that Wolbachia wVulC, which naturally induces feminization in Armadillidium vulgare, induces the development of female secondary sexual characters in transinfected Cylisticus convexus adult males. However, this does not demonstrate that wVulC induces feminization in C. convexus since feminization is the conversion of genetic males into functional females that occurs during development. Nevertheless, it suggests that C. convexus may represent a feminization model suitable for further development. Knowledge about C. convexus sexual differentiation is also essential for comparative analyses, as feminization is thought to take place just before or during sexual differentiation. Consequently, we first described gonad morphological differentiation of C. convexus and compared it with that of A. vulgare. Then, wVulC was injected into male and female C. convexus adult individuals. The feminizing effect was demonstrated by the combined appearance of female secondary sexual characters in transinfected adult males, as well as the presence of intersexes and female biases in progenies in which wVulC was vertically transmitted from transinfected mothers. The establishment of a new model of feminization of a Wolbachia strain in a heterologous host constitutes a useful tool towards the understanding of the molecular mechanism of feminization.

High Levels of Multiple Infections, Recombination and Horizontal Transmission of Wolbachia in the Andricus mukaigawae (Hymenoptera; Cynipidae) Communities

Wolbachia are maternally inherited endosymbiotic bacteria of arthropods and nematodes. In arthropods, they manipulate the reproduction of their hosts to facilitate their own spread in host populations, causing cytoplasmic incompatibility, parthenogenesis induction, feminization of genetic males and male-killing. In this study, we investigated Wolbachia infection and studied wsp (Wolbachia surface protein) sequences in three wasp species associated with the unisexual galls of A. mukaigawae with the aim of determining the transmission mode and the reason for multiple infections of Wolbachia. Frequency of Wolbachia infected populations for A. mukaigawae, Synergus japonicus (inquiline), and Torymus sp. (parasitoid) was 75%, 100%, and 100%, respectively. Multiple Wolbachia infections were detected in A. mukaigawae and S. japonicus, with 5 and 8 Wolbachia strains, respectively. The two host species shared 5 Wolbachia strains and were infected by identical strains in several locations, indicating horizontal transmission of Wolbachia. The transmission potentially takes place through gall tissues, which the larvae of both wasps feed on. Furthermore, three recombination events of Wolbachia were observed: the strains W8, W2 and W6 apparently have derived from W3 and W5a, W6 and W7, W4 and W9, respectively. W8 and W2 and their respective parental strains were detected in S. japonicus. W6 was detected with only one parent (W4) in S. japonicus; W9 was detected in Torymus sp., suggesting horizontal transmission between hosts and parasitoids. In conclusion, our research supports earlier studies that horizontal transmission of Wolbachia, a symbiont of the Rickettsiales order, may be plant-mediated or take place between hosts and parasitoids. Our research provides novel molecular evidence for multiple recombination events of Wolbachia in gall wasp communities. We suggest that genomic recombination and potential plant-mediated horizontal transmission may be attributable to the high levels of multiple Wolbachia infections observed in A. mukaigawae and S. japonicus.

Life History Traits ofTalicada nyseus(Lepidoptera: Lycaenidae) Butterfly Under Laboratory Conditions

The butterfly Talicada nyseus G. (Lepidoptera: Lycaenidae) is abundant in India and Sri Lanka (Karunaratne, et al., 2002). In India, this butterfly is chiefly found in the peninsular area, Maharashtra, Karnataka, Punjab and foothills of the Himalayas (Singh, 2005). The host plants of this butterfly include Kalanchoe spp. (Saxifragales: Crassulaceae). Adult Talicada nyseus feed on nectar of surrounding flowering plants but are also reported to feed on lichens (Karunaratne, et al., 2002). Recently it has been discovered that Talicada nyseus is infected with maternally inherited Wolbachia bacteria (Ankola, et al., 2011; Salunke, et al., 2012) and exhibits a female biased sex ratio (Ankola, et al., 2011). It is suspected that the presence of the female biased sex ratio in this butterfly is caused by its endosybiont Wolbachia. As an endosymbiont, Wolbachia is known to cause female biased sex ratio in butterfly hosts by inducing two distinct reproductive anomalies: feminization of genetic males (Hiroki et al., 2004) and male killing (Jigginset al., 2001; Charlat et al., 2005). It is essential to record scientific data regarding the life history traits of Talicada nyseus naturally infected with Wolbachia. In the present report life history traits of Talicada nyseus which harbor Wolbachia infection were studied under controlled conditions. The individual Talicada nyseus specimens used for the study were collected from a laboratory reared population which was previously confirmed to be heavily infected with Wolbachia. Five individual mated pairs were used separately for the present study. The life cycle was analyzed at 28.09 ± 0.564° C. The data collected were statistically analyzed by paired t-test with the help of SPSS 7.5. Wolbachia infection in this butterfly was previously documented by Ankola etal. (2011). The fecundity of Talicada nyseus was found to be ranging from 61.6± 12.08 to 66.4 ± 17.75 (Table 1). The fecundity data obtained from the present study is in agreement with our previous report (Ankola et al., 2011). More than 95% hatchability was recorded during the present investigation indicating that there might not be male-killing induced by Wolbachia in Talicada nyseus (Jiggins et al., 2000; Charlat et al., 2007). The hatching time required for eggs ranged from 7.4 ± 1.83 to 9.6 ± 2.71 (Table 1). Furthermore, the time required for the

Wolbachia Infection in Populations of Ostrinia furnacalis: Diversity, Prevalence, Phylogeny and Evidence for Horizontal Transmission

Wolbachia are maternally inherited endosymbiotic bacteria infecting a wide range of arthropods and filarial nematodes. They can induce various reproduction alterations in their hosts, including thelytokous parthenogenesis, cytoplasmic incompatibility (CI), feminization of genetic males and male killing. Here we investigated diversity and prevalence patterns of Wolbachia infection in 43 geographical populations of the Asian corn borer, Ostrinia furnacalis, in China and one population in North Korea. Based on Wolbachia surface protein gene (wsp) sequences, nine strains of Wolbachia (wFur1-wFur9), belonging to supergroups A and B, were identified in populations of O. furnacalis with an average infection rate of 10.5%. Superinfection commonly appeared in individuals of O. furnacalis and coinfection patterns were very complex. There was no specific pattern for the prevalence and distribution of the nine Wolbachia strains suggesting an intricate evolutionary history of Wolbachia infection in this species. The genetic similarity of the wFur1-wFur9 strains with those detected in two parasitoids of O. furnacalis, Macrocentrus cingulum and Lydella grisescens, strongly suggests host-parasitoid horizontal transmission.

Absence of Wolbachia in the workers of Asian honeybee, Apis cerana indica

Wolbachia is a group of cytoplasmically inherited bacteria that can cause reproductive alterations in arthropods including parthenogenesis, reproductive incompatibility and feminization of genetic males. Wolbachia are found in a well studied group of insects, but there is a lack of data on their distribution. Workers of the honeybee sub species Apis cerana indica, collected from different parts of Karnataka, India were screened by PCR for Wolbachia, because this endosymbiont has been implicated in causing thelytoky in other Hymenoptera. In the present communication, we report the absence of Wolbachia endosymbiont in the workers of honeybee collected from different geographic locations of Karnataka using Wolbachia specific 16S rDNA polymerase chain reaction enzymes.DOI: http://dx.doi.org/10.3126/ijls.v5i1.5230 International Journal of Life Sciences Vol.5(1) 2011 19-24

Wolbachia as an “Infectious” Extrinsic Factor Manipulating Host Signaling Pathways

Wolbachia pipientis is a widespread endosymbiont of filarial nematodes and arthropods. While in worms the symbiosis is obligate, in arthropods Wolbachia induces several reproductive manipulations (i.e., cytoplasmic incompatibility, parthenogenesis, feminization of genetic males, and male-killing) in order to increase the number of infected females. These various phenotypic effects may be linked to differences in host physiology, and in particular to endocrine-related processes governing growth, development, and reproduction. Indeed, a number of evidences links Wolbachia symbiosis to insulin and ecdysteroid signaling, two multilayered pathways known to work antagonistically, jointly or even independently for the regulation of different molecular networks. At present it is not clear whether Wolbachia manipulates one pathway, thus affecting other related metabolic networks, or if it targets both pathways, even interacting at several points in each of them. Interestingly, in view of the interplay between hormone signaling and epigenetic machinery, a direct influence of the “infection” on hormonal signaling involving ecdysteroids might be achievable through the manipulation of the host’s epigenetic pathways.

Establishment of a new continuous cell line of Drosophila melanogaster strain infected by the intracellular endosymbiotic bacterium Wolbachia pipientis under natural conditions

Wolbachia pipientis is an obligately intracellular bacterium infecting a number of arthropod and nematode species. At the body level, Wolbachia infection may cause parthenogenesis, feminization of genetic males, male killing, or cytoplasmic incompatibility; it may also be asymptomatic. Of special interest is DNA transfer from Wolbachia to the host insect genome, which was discovered recently. At the cellular level, the effects caused by Wolbachia have been studied more poorly. Only one of the known insect cell lines has been obtained from an insect species (the mosquito Aedes albopictus) infected by Wolbachia. In this study, a continuous cell line Dm2008Wb1 has been obtained from embryos of Drosophila melanogaster infected under natural conditions. Wolbachia both persists in a primary cell culture and is retained upon its transformation into a continuous culture. The presence of this bacterium in cells in a free form is evidenced by the fact that tetracycline treatment can cure the cells of Wolbachia and by successful transfer of Wolbachia to another cell line (S2), where it has not been detected before.

Frequency of infection with A and B supergroup Wolbachia in insects and pests associated with mulberry and silkworm

Wolbachia is a ubiquitous, Gram-negative,vertically transmitted, alpha-proteobacterium that causes an array of reproductive abnormalities including cytoplasmic incompatibility, feminization of genetic males, parthenogenesis in a number of insect species, among others. Wolbachia is now being exploited as an agent for pest and vector control. Previous surveys indicated that it is commonly seen in 16-76% of arthropods. In this paper, using polymerase chain reaction assay based on specific amplification of the ftsZ -A and -B supergroup Wolbachia gene fragments, we found that 30% of insects and pests screened were positive for Wolbachia. Among them 66.7% harbour double Wolbachia infection, while 33.3 % harbour single Wolbachia infection. These results indicate widespread infection with both double and single Wolbachia, and provide a wealth of information to exploit this endobacterium for the management of pests and vectors.

Phylogenetic diversity of the intracellular symbiont Wolbachia in termites

The genus Wolbachia (class Alphaproteobacteria) encompasses obligately intracellular bacteria that are cytoplasmically transmitted in arthropods and Wlarial nematodes (O’Neill et al., 1997; Stouthamer et al., 1999; Werren, 1997). They are found in greater than 20% of all insect species, numerous other arthropods, and Wlarial nematodes (Bandi et al., 1998; Jeyaprakash and Hoy, 2000; Werren et al., 1995). Unlike most other obligately intracellular bacteria, Wolbachia form a monophyletic clade comprised of both mutualistic and parasitic lineages, that highlight the diversity of symbiotic associations. In arthropods, Wolbachia are commonly known as reproductive parasites, since they distort host reproductive strategies to selWshly enhance their maternal transmission into the next generation (Werren, 1997). Examples of the eVects of Wolbachia infection include male-killing, feminization of genetic males, parthenogenesis, and cytoplasmic incompatibility. In contrast, the Wolbachia lineages infecting Wlarial nematodes are beneWcial symbionts required for host fertility and larval viability (Bandi et al., 2001). The gene phylogenies of Wolbachia have shown the existence of eight major clades or ‘supergroups’ (A–H), as well as some additional lineages (Bordenstein and Rosengaus, 2005; Casiraghi et al., 2005; Lo et al., 2002; Rowley et al., 2004). Supergroups A and B include most of the parasitic Wolbachia found in arthropods (Werren et al., 1995). The phylogeny of these parasites matches that of their hosts poorly, indicating that they are frequently transferred horizontally among diverse taxa. Clades C and D include the majority of the mutualistic Wolbachia found in Wlarial nem-

Cardinium symbionts cause cytoplasmic incompatibility in spider mites

Intracellular symbiotic bacteria belonging to the Cytophaga-Flavobacterium-Bacteroides lineage have recently been described and are widely distributed in arthropod species. The newly discovered bacteria, named Cardinium sp, cause the expression of various reproductive alterations in their arthropod hosts, including cytoplasmic incompatibility (CI), induction of parthenogenesis and feminization of genetic males. We detected 16S ribosomal DNA sequences similar to those of Cardinium from seven populations of five spider mite species, suggesting a broad distribution of infection of Cardinium in spider mites. To clarify the effect of Cardinium on the reproductive traits of the infected spider mites, infected mites were crossed with uninfected mites for each population. In one of the populations, Eotetranychus suginamensis, CI was induced when infected males were crossed with uninfected females. The other six populations of four species showed no reproductive abnormalities in the F(1) generation, but the possibility of CI effects in the F(2) generation remains to be tested. One species of spider mite, Tetranychus pueraricola, harbored both Cardinium and Wolbachia, but these symbionts seemed to have no effect on the reproduction of the host, even when the host was infected independently with each symbiont.

Evidence for a Global Wolbachia Replacement in Drosophila melanogaster

Wolbachia are maternally inherited intracellular alpha-Proteobacteria found in numerous arthropod and filarial nematode species. They influence the biology of their hosts in many ways. In some cases, they act as obligate mutualists and are required for the normal development and reproduction of the host. They are best known, however, for the various reproductive parasitism traits that they can generate in infected hosts. These include cytoplasmic incompatibility (CI) between individuals of different infection status, the parthenogenetic production of females, the selective killing of male embryos, and the feminization of genetic males. Wolbachia infections of Drosophila melanogaster are extremely common in both wild populations and long-term laboratory stocks. Utilizing the newly completed genome sequence of Wolbachia pipientis wMel, we have identified a number of polymorphic markers that can be used to discriminate among five different Wolbachia variants within what was previously thought to be the single clonal infection of D. melanogaster. Analysis of long-term lab stocks together with wild-caught flies indicates that one of these variants has replaced the others globally within the last century. This is the first report of a global replacement of a Wolbachia strain in an insect host species. The sweep is at odds with current theory that cannot explain how Wolbachia can invade this host species given the observed cytoplasmic incompatibility characteristics of Wolbachia infections in D. melanogaster in the field.

Microorganisms and parthenogenesis

Endosymbionts are being discovered in unprecedented numbers of invertebrate species. The bacterium Wolbachia pipientis alone is carried by some 20% of all insect species, in which it is responsible for such reproductive manipulations as cytoplasmic incompatibility, feminization of genetic males, male-killing and parthenogenesis. The discovery of Wolbachia-induced thelytoky in hymenopteran parasitoids has initiated the successful search in other groups of haplodiploid species. Haplodiploidy has arisen at least 17 times during animal evolution and intracellular bacteria that effect sexual development have been found in many of these haplodiploid groups, rekindling the question regarding the origin of haplodiploidy. The detection of Wolbachia in parthenogenetic thrips (Thysanoptera). booklice (Psocoptera), springtails (Collembola), mites (Acari) and Xiphinematobacter in dragger nematodes (Dorylaimida) raises the possibility of bacterial-induced parthenogenesis in diplodiploid species as well. Recent studies indicate that Wolbachia might be just one of a rapidly increasing list of intracellular bacteria capable of inducing parthenogenesis in their host. The search for novel endosymbionts will rely heavily on previous taxonomic work, but the possibilities for discovery remain boundless.

Cloning and characterization of a gene encoding glutathione-regulated potassium-efflux system protein KefKL from the endosymbiont Wolbachia.

The maternally inherited intracellular symbiont Wolbachia is well known for inducing a variety of reproductive and developmental abnormalities in the diverse arthropod hosts it infects. It has been implicated in causing cytoplasmic incompatibility (CI), parthenogenesis, feminization of genetic males and male killing in different hosts. However, the molecular mechanisms by which this fastidious bacterium causes these abnormalities have not yet been determined. In our study, representational difference analysis (RDA) was used to analyze the genomic difference between different Wolbachia strains. A gene encoding glutathione-regulated potassium-efflux system protein KefKL from Wolbachia in Drosophila simulans Riverside (w Ri) was isolated. The homologous genes from Wolbachia in Drosophila melanogaster yw67c23 (wMel) and Wolbachia in Drosophila melanogaster CantonS (wMelCS) were also cloned and sequenced. Sequence analysis showed that these deduced amino acid sequences contained two important motifs: Na+/H+ antiportor and NAD binding domain, which shared conserved sequences among different strains. Considering the crucial function of KefKL for ionic homeostasis, this gene might play an important role in Wolbachia physiology. Further study indicated that there was no homologue detected from Wolbachia in Drosophila simulans DSW/Mau (wMa) and Wolbachia in Drosophila simulans Noumea (wNo). Whether Wolbachia contained KefKL (or the homologous gene) was consistent with the phylogenetic studies using wsp sequences, which showed that wMa and wNo were grouped into one branch, while w Ri, wMel and wMelCS were more closely related.

Cloning and characterization of a gene encoding phage- related tail protein (PrTP) of endosymbiont Wolbachia

Wolbachia is an obligatory, maternally inherited intracellular bacterium, known to infect a wide range of arthropods. It has been implicated in causing cytoplasmic incompatibility (CI), parthenogenesis, the feminization of genetic males and male-killing in different hosts. However, the molecular mechanisms by which this fastidious bacterium causes these reproductive abnormalities have not yet been determined. In this study, we report on the cloning and characterization of the gene encoding phage-related tail protein (PrTP) from Wolbachia in Drosophila melanogaster CantonS (wMelCS) and from Wolbachia in Drosophila melanogaster yw67c23 (wMel) by representational difference analysis (RDA) and ligation-mediated PCR (LM-PCR). The functionality of a bipartite nuclear localization signal sequence (NLS) of the gene was also successfully tested in Drosophila S2 cells. PrTP expression in various strains of Wolbachia was investigated. Our results suggest that PrTP may not induce CI directly. However, the existence of prtp provided direct evidence of phage-mediated horizontal gene transfer (HGT) that might play an important role in a variety of reproductive abnormalities of Wolbachia.

Inherited microorganisms, sex-specific virulence and reproductive parasitism.

Parasites show an amazing repertoire of adaptations, highlighted by complex life cycles that allow both survival in the host and transmission among hosts. However, there is one heterogeneous group of microorganisms whose adaptations are perhaps even more surprising: parthenogenesis induction, feminization of genetic males, killing of male hosts and sperm-mediated sterilization of uninfected eggs. The common feature of these microorganisms is their mode of transmission: inheritance from mother to offspring. Here, we present an introduction to hereditary symbiosis, focusing on microsporidia and bacteria that manipulate host reproduction in arthropods (reproductive parasites). We also discuss the implications of one of these microorganisms, Wolbachia, for the control of arthropod pests and vectors and for the therapy of filarial diseases. Finally, we discuss whether some parasites of vertebrates might show sex-specific virulence.

Cytological and Molecular Evidence forWolbachia Infection in Uzi Flies of Exorista Species.

The cytoplasmically inherited bacterial symbiont, Wolbachia is well known for inducing a variety of reproductive abnormalities in the diverse arthropod hosts it infects. Wolbachia has been implicated in causing cytoplasmic incompatibility, parthenogenesis, and the feminization of genetic males in different hosts. In the present investigation, electron microscopy and PCR technology was applied on uzi flies of Exorista species (Diptera : Tachinidae), serious pests of silkworm Bombyx mori L. TEM examination of uzi flies of Exorista species showed Wolbachia in the reproductive tissues. Details of the ultrastructure of Wolbachia are described. The application of PCR technique revealed that the Wolbachia is present in uzi fly populations of Exorista species collected from different localities. Thereby it creates a lot of scope for future research on the management of uzi flies by means of Wolbachia.

Male-killing Wolbachia in a flour beetle.

The bacteria in the genus Wolbachia are cytoplasmically inherited symbionts of arthropods. Infection often causes profound changes in host reproduction, enhancing bacterial transmission and spread in a population. The reproductive alterations known to result from Wolbachia infection include cytoplasmic incompatibility (CI), parthenogenesis, feminization of genetic males, fecundity enhancement, male killing and, perhaps, lethality Here, we report male killing in a third insect, the black flour beetle Tribolium madens, based on highly female-biased sex ratios of progeny from females infected with Wolbachia. The bias is cytoplasmic in nature as shown by repeated backcrossing of infected females with males of a naturally uninfected strain. Infection also lowers the egg hatch rates significantly to approximately half of those observed for uninfected females. Treatment of the host with antibiotics eliminated infection, reverted the sex ratio to unbiased levels and increased the percentage hatch. Typically Wolbachia infection is transmitted from mother to progeny, regardless of the sex of the progeny; however, infected T. madens males are never found. Virgin females are sterile, suggesting that the sex-ratio distortion in T. madens results from embryonic male killing rather than parthenogenesis. Based on DNA sequence data, the male-killing strain of Wolbachia in T. madens was indistinguishable from the CI-inducing Wolbachia in Tribolium confusum, a closely related beetle. Our findings suggest that host symbiont interaction effects may play an important role in the induction of Wolbachia reproductive phenotypes.