Two Grapholita congeners, G. dimorpha and G. molesta, are internal fruit feeders and their young larvae cause serious damages to pome and stone fruits in Korea. They share similar morphological and biological characters not to be easily discriminated. We needed to develop molecular markers using diagnostic primers and PCR-RFLP with specific sequences in ND4 region. Two species have similar sex pheromone components (Z8-12:Ac and E8-12:Ac) although their composition ratios are different. In fields, G. molesta males were more captured in lures with higher Z8 component ratio than G. dimorpha males. Addition of Z8-12OH, minor sex pheromone component prevented G. dimorpha from capturing G. molesta males. In electroantennogram (EAG) bioassay, these two species males showed significant electric responses in their own sex pheromone ratios. An addition of Z8-12:OH to the major sex pheromone components significantly suppressed the EAG response of G. dimorpha, while it did not change that of G. molesta. A deep sequencing analysis of transcripts of both species pheromone glands identified sex pheromone biosynthesis genes including fatty acid synthase, desaturases, fatty acyl reductase (FAR), and aldehyde reductase. The presence of delta 10 desaturase in both species suggests that a double bond at C8 position in dodecenyl acetate is produced by desaturation at C10 position of tetradecenyl fatty acid and subsequent β-oxidation, which is then reduced at carboxylic acid by FAR to be acetylated by acetyl transferase. High sequence variation of FAR genes of G. molesta and G. dimorpha suggests their stereoisomer substrate preference, which may exert a driving force for this speciation with delta 10 desaturase.

성범죄에 대한 불안이 확산되면서 정부는 「성범죄자 알림e」등 특단의 조치를 마련하였다. 그러나 현재로서는 성범죄자 검색을 하기 위해 공인인증서, 주민등록번호 기입 등 추가적인 절차를 거쳐야하고, 접속이 되더라도 주어지는 정보는 매우 제한적이라 그 실효성에는 다소 의문이 든다. 「성범죄자 알림e」제도의 근거가 되는 <성폭력범죄의 처벌 등에 관한 특례법>이 개인정보침해방지를 비롯하여 인권보호를 중시한 결과라고 할 수 있다. 미국도 수년 전부터 성범죄자 신상공개와 알림이 서비스가 포함된 SORNA 정책을 시행하고 있다. SORNA 제도는 관련법률 위반시 최고 10년의 징역형이 부과되는 강력한 정책이며, 연방정부를 비롯하여 지방 50개주에서도 모두 시행할 정도로 보편화 되어 있다. 물론, 개인의 사생활 침해의 위헌문제, 예산의 부족, 사법전자시스템의 지역별 편차, 정책효율성에 대한 연구부족 등 개선할 점도 많이 지적받지만 SORNA 제도는 현재 미국 국민들에게 광범위한 지지를 받으며 운영되고 있는 정책 가운데 하나로 평가받는다. 개인정보보호와 성범죄자에 대한 테러 가능성 등 아직 해결해야 할 문제들이 많은 우리나라의 성범죄자 신상공개에 대해서 미국을 비롯한 다른 나라들의 사례는 좋은 선례(先例)가 될 것이며, 그 잘된 점은 받아들여서 더욱 개선하고 잘못한 점은 반면교사(反面敎師)로 삼아 일보해 나아가야 할 것이다. 다른 나라와의 비교를 통해서 우리의 현재 모습을 객관적으로 평가해보고 더 나은 방향을 모색해 보아, 한국의 「성범죄자 알림e」제도가 참신한 성공사례로 자리잡아 국제사회에 모범이 될 것을 기대해 본다.

목적: 본 연구는 우리나라 성인의 건강형평성 주요 척도에 따른 백내장을 분석함으로써 눈 건강 형평성을 평가하고자 하였다. 방법: 국민건강영양조사(2009) 안검진 조사 데이터를 이용하여 무수정체안을 제외한 만 20세 이상의성인7,412명을 대상으로 소득수준, 교육수준, 직업, 지역에 따른 백내장의 유병률 및 오즈비를 분석하였다. 백내장은 안과전문의가 slit-lamp를 이용하여 검사하였다. 건강형평성 주요 척도에 따른 유병률은 t-검정 및 x² 검정하였고, 오즈비(odds ratio)는 로지스틱 회귀분석을 이용하였으며, 유의수준은 0.05로 PASW18.0을 사용하여 분석하였다. 결과: 백내장의 표준화 유병률은 26.4%이었다, 유병률은 가구소득‘하’에서41.2%, ‘초졸 이하’59.9%.‘무직’53.9%,‘도시지역’62.8%이었다. 건강형평성 주요 척도에 따른 백내장의 오즈비는 50세 이상군에서 가구소득이 ‘하’일 때 2.60(CI, 196-344), ‘무직군’일 때 2.33(CI, 1.49-3.34), 농촌지역에서 1.24(CI, 0.99-1.56)로 높게 나타났다. 20-49세군은 ‘초졸 이하’에서 5.48(CI, 2.71-11.06)이었고, ‘농림어업 숙련 종사지군’에서 .33(CI, 1.37-8.10)으로 높았다. 농촌지역에서 가구소득이 ‘하’일 때 오즈비는 2.33(CI, 1.35-3.69), ‘초졸 이하’일 때 2.03(CI, 0.97-4.26), ‘단순노무 종사지군’에서 1.28(CI, 0.52-3.14)로 도시지역에 비해 높았다. 여자의 경우 가구소득이‘하’에서 1.60(CI, 1.12-2.30), ‘초졸 이하’에서 1.79(CI, 1.09-2.92)로 남자에 비해 높게 나타났다. 결론: 낮은 사회경제적 상태에서 백내장의 유병률과 오즈비가 증가하여 우리나라 성인의 눈 건강 불평등이 존재하였으며, 이를 위해 저소득층을 위한 종합적인 일차안보건의료정책이 필요하다. 또한 외국의 안보건정책과의 비교를 통해 기존의 치료 위주의 보건정책보다는 예방과 교육 중심의 보건정책의 개발이 요구된다.

오늘날 성범죄사건은 다른 강력사건과 마찬가지로 재범률이 상당히 높게 나타나고 있지만, 다면적이고 복합적인 원인에 의해 발생하는 대다수의 성범죄사건에 공통적이고 일률적으로 적용하여 치료할 수 있는 이론과 프로그램은 없다. 그렇기 때문에 성범죄자들의 재범방지를 위해 교정기관에서의 전문적인 치료프로그램은 더욱더 필요하다. 성범죄자들의 전문적인 치료를 위한 접근은 첫째, 성범죄와 관련된 사고와 행동 그리고 일탈적 성행위를 치료하기 위한 인지행동적 접근이다. 둘째, 성범죄 피해자에 대한 공감대 형성과 동정심을 유발시키고 성범죄 행위에 대한 책임감을 가르치는 심리교육적 접근이다. 셋째, 성범죄자들의 생리적 충동을 억제시켜 줄 수 있는 약물학적 접근이다. 아울러 성범죄자들을 위한 다양한 치료프로그램들이 공유하는 핵심적 요소들은 범죄행위와 관련된 요인분석, 왜곡된 인지과정의 재구성, 성적 충동 억제, 범죄피해자에 대한 감정이입 등으로 해결하려고 한다. 결과적으로 시간이 흐를수록 잔인해지고 흉폭해지는 성범죄의 재범을 방지하기 위해서라도 첫째, 성폭력범죄자들에 대한 치료 목적의 재활 프로그램을 실시하고, 나아가 교정기관과 지역사회의 전문적인 치료가 연계되어야 한다. 둘째, 성범죄자 개인의 특성에 맞는 왜곡된 사고와 행동방식 교정에 집중된 치료프로그램을 실시하여야 한다. 셋째, 실질적인 교육시간이나 여건 등을 적극 고려하고 전문인력을 확보하여 치료프로그램을 운영해야 한다.

경북의 자두 주요 생산지인 경산시와 의성군내 8개의 자두과원을 선정하여, 2010년과 2011년에 주요 심식나방류인 복숭아순나방, 복숭아순나방붙이, 복숭아심식나방의 발생상을 성페로몬 트랩을 이용하여 조사하였다. 또한 경산지역에서는 과수원 내부와 외부에서 포획된 개체수 자료를 이용하여 내외부 발생량을 비교하였다. 경산에서 복숭아순나방과 복숭아순나방붙이 발생은 의성보다 약 1주일 정도 빠르게 나타났다. 복숭아순나방은 3월 하순에 발생을 시작하여, 4월 하순 최성기를 이루었으며, 이후 세대는 6월 중순, 7월 중순, 8월 중순에 성충 최성기를 보였다. 반면 복숭아심식나방은 두 지역간의 차이가 없었으며, 6월 상순에 발생을 시작하여 9월 중순까지 2-3회의 발생 최성기를 보였다. 복숭아심식나방의 경우 2010년은 전형적인 2회 최성기를 보였으나 2011년에는 3회 최성기를 보였다. 연간 복숭아순나방, 복숭아순나방붙이, 복숭아심식나방의 발생량비는 경산지역에서 63-47:16-35:20-18%였고, 의성지역은 51-46:18-13:31-36%로 나타났다. 복숭아순나방과 복숭아순나방붙이의 경우 과수원 내부와 외부에서 포획량의 차이는 없었다.

대중매체로서 신문은 공중에게 사회에서 일어나는 중요한 현안에 대한 정보 를 전달할 뿐만 아니라, 공중이 건전한 가치와 태도를 형성할 수 있도록 돕는 역할을 한다. 최근 언론의 성범죄 관련 보도 양태를 볼 때, 과연 언론이 이러 한 기능을 제대로 수행하고 있는지 의문이다. 특히 성범죄 보도에 있어 언론의 선 정주의가 도를 넘었다는 비판이 오랫동안 계속되었다. 언론이 성범죄의 선정성과 폭력성을 강조하여 보도할 때, 범죄 보도를 통한 규범 강화, 사회 안정, 치안 강화 등의 순기능은 감소하고 모방 범죄나 과도한 공포감 조성 등 역기능이 증가할 수 있다. 또한 우리나라 음란물 소비는 과거 어느 때에 비해 급격하게 증가한 것이 사실이다. 비록 성인일지라도 과도한 음란물 소비는 성에 대해 잘못된 관념을 유 발하고 성에 관한 현실을 왜곡되게 파악하게 만들 수 있다. 본 연구는 성범죄 보도의 선정성과 음란물 노출이 성 관련 감정, 인지, 행위 의 도에 미치는 영향을 살펴보기 위해 남자 대학생을 대상으로 실험 연구를 수행하였 다. 연구결과, 음란물 노출이 높은 대학생 집단은 그렇지 않은 집단에 비해 도구적 성 인식과 성 비행 시행의지가 상대적으로 높은 것으로 나타났다. 하지만, 성범죄 기사의 선정성에 대한 영향은 추가적인 연구가 필요한 것으로 나타났다. 왜냐하면 실험적으로 처치된 선정성 고/저 집단의 차이는 나타나지 않았지만, 개별 피험자의 뉴스 기사에 대한 선정성 평가는 성 충동과 유의미한 관련이 있는 것으로 나타났 기 때문이다.

최근 들어 하우스재배 감귤을 중심으로 발생이 증가하고 있는 귤애가루깍지벌레에 대해 효율적인 발생예찰과 함께 방제시기를 결정하기 위하여 합성 성페로몬을 이용하여 시기별 발생특성을 조사하였다. 귤애가루깍지벌레의 수컷 성충은 합성 성페로몬뿐만 아니라 색에도 반응하였다. 성페로몬의 농도는 5.0 mg까지 농도가 증가할수록 유인력이 높았다. 귤애가루깍지벌레 수컷 성충은 연 4회 발생되고 있었으며, 월동 후 수컷 성충이 처음 발생되기 시작하는 시기는 4월 중하순이었다. 수컷 성충발생이 가장 많은 시기는 제 1세대 발생기인 7월 상중순이었다. 성페로몬트 랩에 유인된 귤애가루깍지벌레 수컷 성충은 한 세대 내에서 3회의 발생성기가 나타났으며, 이는 귤애가루깍지벌레가 1~3령 약충으로 월동하기 때문인 것으로 추정되었다. 트랩에 유인된 수컷 성충의 밀도와 나무의 가지당 평균밀도와는 높은 정(+)의 상관을 갖고 있었다. 수컷 성충의 최대 유인시기를 이용하여 1령 약충 발생 시기를 추정할 수 있었으며, 그 적산온도는 산란전 기간과 비슷한 350DD이었다.

Chalcogenide-based semiconductors, such as CuInSe2, CuGaSe2, Cu(In,Ga)Se2 (CIGS), and CdTe have attracted considerable interest as efficient materials in thin film solar cells (TFSCs). Currently, CIGS and CdTe TFSCs have demonstrated the highest power conversion efficiency (PCE) of over 11% in module production. However, commercialized CIGS and CdTe TFSCs have some limitations due to the scarcity of In, Ga, and Te and the environmental issues associated with Cd and Se. Recently, kesterite CZTS, which is one of the In- and Ga- free absorber materials, has been attracted considerable attention as a new candidate for use as an absorber material in thin film solar cells. The CZTS-based absorber material has outstanding characteristics such as band gap energy of 1.0 eV to 1.5 eV, high absorption coefficient on the order of 104cm-1, and high theoretical conversion efficiency of 32.2% in thin film solar cells. Despite these promising characteristics, research into CZTS-based thin film solar cells is still incomprehensive and related reports are quite few compared to those for CIGS thin film solar cells, which show high efficiency of over 20%. The recent development of kesterite-based CZTS thin film solar cells is summarized in this work. The new challenges for enhanced performance in CZTS thin films are examined and prospective issues are addressed as well.

This study was conducted to see the initial increasing time of population of citrus leafminer(CLM) in spring and early summer seasons in 2007-2011. CLM adults were monitored using sex pheromone trap which is mainly composed of Z,Z-7, 11-hexadecadienal in the 4, 8 and 5 orchards of the east, south and north part in jeju island, respectively during 2007-2011 seasons. The traps and lures were changed at 10 days and 1 month interval, respectively. Though CLMs were captured on traps from March or April, it was 17, 28 and 28 May in 2007, 16, 26 May and 5 June in 2008, 8, 26 and 26 May in 2009, 27 May, 7 and 7 June in 2010 and 25 May, 2, 2 June in the south, east and north part of Jeju Island, respectively that the CLM population rapidly began to increase toward peaking. The accumulated temperature except less than developmental zero, 12.1 Ujiye T 1990). from January was 248.0, 270.5 and 289.7 in 2007, 193.2, 203.8 and 261.4 in 2008, 202.0, 245.5 and 259.9 in 2009, 261.4, 192.2 and 268.3 in 2010 and 243.4, 246.3 and 252.4 in 2011 at that time. After May overwintered CLM adults are little possible to be counted to the number of captured CLM because adult longevity is about 100 in degree days (Lim 2006). CLM populations in the south part of Jeju Island in first CLM adults increasing periods during 2007-2011 is higher than other parts.

The box tree pyralid, Glyphodes perspectalis, was reared on an artificial diet based on dried powder of box tree leaves, Buxus microphylla var. koreana, and INSECTA F-II (Nihon Nosan Co., Ltd) at a ratio of 3:7 (w:w) and analyzed in their developmental characteristics from 1st to 4th generation. The developmental period of larva reared on artificial diet was longer than that of larva reared on host plant. Significant difference in larval period was also observed between 1st and other generation groups. Pupation rate was the highest in 4th generation followed by 3rd, 2nd, 1st and host plant group. Significant difference in pupal period was noted between 1st and 3rd generation group. Emergence rate was the highest in 4th generation group followed by 3rd, host plant, 1st and 2nd generation group. There is a significant difference in male and female size between 1st and 4th generation group. Our result indicated that stable rearing of box tree pyralid through the year is possible by artificial diet, and the best adaptation to artificial diet was achieved at 4th generation. The pheromone components of this moth have been identified as (Z)-11-hexadecenal (Z11-16:Ald), (E)-11-hexadecenal (E11-16:Ald), and (Z)-11-hexadecenol (Z-11-16:OH). We did several field tests, and found that there was a difference between Korea and Japan population.

In haplodiploid sex determination, females are sexually reproduced from fertilized diploid eggs, and males from unfertilized haploid eggs. Haplodiploid sex determination seems simple in that sex depends simply on the ploid level. However, the underlying genetic mechanisms are thought to be much more complicated than expected. Among them, a powerful proposed mechanism is genomic imprinting. All epigenetic on-off systems require target genes, unless the systems target histone proteins on chromosomes. For Hymenoptera, a good candidate target gene in terms of sex determination is known either as feminizer (fem) or transformer (tra) in many insects. These two genes are essential for expressing femaleness. In most Hymenopteran insects, the maternal tra seems to be methylated and consequently not expressed, while the paternally derived tra gene is not methylated. Therefore, a fertilized egg with the paternally derived active tra gene will develop into a functional female. Like all Hymenoptera, ants (Formicidae) have haplodiploid sex determination. In Vollenhovia emeryi, however, queens are produced clonally while workers derive from fertilized eggs. Males are haploid, likewise deriving from fertilized eggs, but only after selective elimination of their maternal genome. Under the conventional genomic imprinting model, we would have expected that the opposite pattern of what is observed in others. Here we present extraordinary sex determination and suggest our hypothesis about genomic imprinting pattern in V. emeryi

This study evaluated a method of sorting X and Y chromosomes based on size using the forward angle light scatter related refractive index (FSC) of a flow cytometer. Hanwoo bulls sperm were separated to X and Y chromosomes by the parameters of FSC or Hoechst 33342 intensity. As a result, using monitor program linked flow cytometry during sorting processing, the purities were or for the X-fraction and or for the Y-fraction in the two sperm sorting methods. There were no differences in the X and Y ratios (X and Y %) between the sperm sorting methods based on FSC or DNA content. The proportions of female and male embryos used for in vitro fertilization and development were or , and or when sperm were processed using the sex sorting method by FSC or Hoechst 33342. In conclusion, further study is needed to determine the optimum procedure and improve the nozzle to enhancing sorting accuracy or efficiency. Also, the findings of this study do not negate the possibility that the difference method of sperm sorting cannot use a UV laser beam.

In mammals, the meiosis division in testes produces equal numbers of two different types of gametes: X chromosome-bearing sperm (X-spermatozoa) and Y chromosomebearing sperm (Y-spermatozoa), which have equal potential to fertilize the oocytes. Therefore, the expected 1: 1 sex ratio is observed. However, under some conditions like endocrine disruptors (EDs) exposure the sex ratio is deviated than the expected with more males or more females. And recently many hypotheses have been postulated to explain the mechanism of sex ratio deviation; however none of them introduced a proven experimental explanation. To solve this enigma, we hypothesized that the differences between X- and Y-spermatozoa survivability under specific conditions due to differences in their chromosome contents are the key leading to the sex ratio alteration. To examine our hypothesis, we combined two techniques; first, hypo-osmotic swelling (HOS) test that was applied to test viability of spermatozoa and second, fluorescence in situ hybridization that was applied on HOS-treated spermatozoa to define sex chromosome composition. In the present study, human spermatozoa were incubated with a group of EDs represent a widespread chemicals in the environment bisphenol A (BPA, 100 μM), nonylphenol (NP, 10 μg/ml), 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD, 2.5 μg/ml), genistein (Gen, 100 μM), and the following pesticides, dibromochloropropane (DBCP, 10 μg/ml), atrazine (Atraz, 500 μM), and diazinone (Diaz, 500 μM) for 6 hr at 37℃ in 5% CO2. Then, the viability of spermatozoa and their sex chromosome contents were evaluated simultaneously. Among seven chemicals studied only four chemicals (Atraz, DBCP, TCDD, and Diaz) significantly decreased Y-sperm viability when compared to those of X-spermatozoa in the same treatment group and viability of Y-spermatozoa when compared to those in the negative and positive (DMSO) control groups (p<0.05). Also, in these four treatment groups the sex ratio of live sperm population was significantly lowered compared to the control groups (p<0.05). Otherwise, Gen, BPA, and NP did not show any significant effect on viability of Yspermatozoa or decreasing sex ratio in live sperm population as compared to the control groups. It has been proven that TCDD, DBCP, and the pesticides decrease the sex ratio, but the same effect was not observed in case of Gen, BPA, and NP. From the present findings, there is no doubt that the EDs may alter sex ratio via decreasing Y-spermatozoa viability.

The α-proteobacterium Wolbachia is maternally inherited and is known to induce reproductive distortions in a wide range of insect taxa such as cytoplasmic incompatibility, feminization, male killing and parthenogenesis (PI). When a female is infected with PI-Wolbachia, she does not need a male to produce female offspring, because the female can produce female offspring via gamete duplication without the aid of sperm. However, in the parasitoid wasp Trichogramma kaykai species, Wolbachia infected parthenogenetic females still produce a fraction of male offspring. Offspring sex ratio for 10 days are different according to each T. kaykai isofemale line that is infected with PI- Wolbachia. This may be caused by complex interactions between Wolbachia and the host genetic backgrounds on converting sex of infected eggs.

Eight female Himalayan tahrs (Hemitragus jemlahicus) were estrus-synchronized, and transcervically inseminated with frozen-thawed semen in September, 2009, about 2 to 3 months earlier than their natural breeding season. Intravaginal progesterone-releasing devices were inserted into vaginas of six Himalayan tahrs on September 7, and the other two on September 8 to suppress luteal function of ovaries. The devices had been placed deep inside the vagina prior to withdrawal on September 23. A day before CIDR removal, a combination of PMSG 400 IU and hCG 200 IU was intramuscularly injected. Forty hours later, frozen-thawed semen was transcervically inseminated. Pregnancy diagnosis was performed 39 days later by analyzing progesterone level of serum. Every treatment was done under anesthesia inducted by xylazine injection. In conclusion, vaginal discharge of cervical mucus, hormonal changes induced by implant-typed or muscularly injectable hormones and widening of cervix enough to insert an insemination gun into uterine body were achieved in non-breeding season. Moreover, the first inseminated Himalayan tahr, 36 hours after CIDR removal was assumed to be pregnant but the fetus may have been lost due to the use of anesthetic drug.

Spermatozoa sorted by flow cytometry have been successfully used to produce offspring in domestic animals and are commercially available for cattle. Also sheath fluid is the important environment for viability of sex-sorted sperm in flow cytometry. The aim of this study was to investigate whether or not HEPES (N-2-hydroxyethylpiperazine-N'-2-Ethanesulfonic acid) has any effect on the viability in sex-sorted Hanwoo (Korean native cattle) sperm. In this study, the semen was collected from Hanwoo of Hoengseong Livestock Cooperation by artificial vagina method then pooled and subjected to cryopreservation in straws. Sperm were cultured for 0, 30, 60 and 120 min with 0, 2.5, 5, 7.5 and 10 mM of HEPES added to the sheath fluid and incubated at 4, 20 and 38, respectively. For the cytometric analysis the frozen-thawed semen was extended with 5 mM HEPES extender to final concentration ( spermatozoa) at 4, 20 and 37. Sperm viability was assessed with SYBR-14 and propidium iodide (PI) staining. This study shows that the viability of sperm was decreased with prolongation of incubation time in all of test. But the viability of sperm which were treated with 38 was gently decreased than that of treated with other temperature. The viability of the control was sharply decreased (p<0.05) than all of the HEPES treatment group at 60 to 120 min in 38. X-sexed sperm was more sensitive than Y-sexed sperm to temperature during f10w cytometry (p<0.05). In conclusion, the results of this study suggest that the sheath fluid with 5 mM HEPES has effect on maintenance of viability after sperm sexing at 37 in Hanwoo.

Haplodiploid sex determination occurs in a wide range of animals, especially in Hymenoptera, where a fertilized egg develops into a diploid female and unfertilized into a haploid male. However, recent studies on diploid functional males in some wasps suggest that the simple addition of paternal gene by fertilization may not be enough to explain female offspring production in the sex determination system. Recently, activation of sex determination gene (tra) was found to have a pivotal role in determining the sex of Nasonia vitripennis. In N. vitripennis, tra is activated only on the paternal genome (i.e. sperm) not on the maternal counterpart (i.e. egg). Such parent specific activation of a gene is controlled by a epigenetic factor, DNA methylation. However, in Trichogramma kaykai, Wolbachia induces female offspring production without sperm. Therefore all female offspring are clonal to the maternal gene. This violates the role of activated sex determination gene (tra) from sperm in the wasp. We hypothesize that Wolbachia has an ability to activate the gene by demethylation. This hypothesis indicates that the target of sex ratio distorting endosymbionts may be an upstream gene. It will enhance our understanding of evolution of haplodiploid sex determination.

The α-proteobacterium Wolbachia pipientis infects a wide range of arthropods and filarial nematodes. Wolbachia is maternally inherited and is known to induce reproductive anomalies such as cytoplasmic incompatibility, feminization, male killing and parthenogenesis induction (PI). Trichogramma kaykai is a tiny wasp that parasitizes on lepidopteran eggs. When a female of the wasp is infected with PI-Wolbachia, the female produces female offspring via gamete duplication without the aid of sperm. As she ages, however, the fraction of male offspring increases. In this study, we investigated the effect of host genetic background on the expression of sex ratio between isofemale lines. Virgin females of six isofemale lines were allowed to lay eggs individually for 10 days. There was the positive relationship between female age and the offspring sex ratio. Furthermore, the sex ratio was significantly different among isofemale lines, implying that the host genetic background had an effect on the sex ratio. Based on the results, evolution of symbiosis in terms of sex ratio and future experimental design are discussed.

The Wolbachia bacterium is known to induce reproductive anomalies in various insect taxa such as cytoplasmic incompatibility, feminization, male killing and parthenogenesis. It is hypothesized that the degree of reproductive anomalies is dependent on the bacterial infection density. In this study, we attempted to test the hypothesis using the tiny egg wasp, Trichogramma kaykai that has served as the model system of parthenogenesis where an unfertilized egg develops into a female due to the bacterial infection. So far this is only found in haplodiploid organisms. The results show that 1) as mothers aged, they started producing male offspring, 2) the sex ratio was negatively correlated with the bacterial infection density, 3) female offspring were more than six times heavily infected with Wolbachia than male offspring in the species. In conclusion, female offspring production, parthenogenesis, is as a function of the Wolbachia bacterial density in this species.