The role of dyadic interactions in the mixed-mating strategies of the mangrove rivulus Kryptolebias marmoratus

The mangrove rivulus Kryptolebias marmoratus a small cyprinodont fish native to tropical and subtropical waters from Florida to Brazil, is one of two known self-fertilizing, hermaphroditic vertebrates of which K. marmoratus displays androdioecy, a complex system of reproduction in which hermaphrodites and males are present. This study describes the behavioral repertoires observed during dyadic interactions in the laboratory. Kryptolebias marmoratus exhibited 23 distinctive acts or behaviors. Acts were divided into four categories： aggressive, submissive, neutral, and reproductive. Leading and following behaviors played important roles in the behavioral repertoires of these fish. In hermaphrodite-male dyads, males exclusively initiated the reproductive process and actively pursued hermaphrodites. When hermaphrodites were paired, there was no evidence that they behaved like other simultaneous hermaphrodites that alternate sexual roles （e.g. serranids）. Hermaphrodites were extremely aggressive towards one another, and the aggressor established dominance rapidly. Male-male dyads were divided into two subdivisions based on the presence or absence of the caudal ocellus on one fish. A caudal ocellus on one male appeared to signal the possibility of a potential mating partner to males lacking it. Pairings of males without an ocellus were similar to hermaphrodite-hermaphrodite dyads in that both members of the pair were aggressive towards one another. These observations may be indicative of interactions taking place in natural communities or assemblages of fish in which both males and hermaphrodites occur and provide evidence on the role of dyadic interactions in the mixed-mating strategies [Current Zoology 56 （1）： 6-17, 2010].

Hotspot of Adult Cuban Treefrog and Cane Toad Multi-organ Abnormality in Suburban South-west Florida

This study represents a continuation of the Florida hotspot of tadpole abnormality found in the Southwest Florida suburban roadside drainage ditches in 2012 to determine if the adult frogs and toads frequenting the study sites were anatomically abnormal.The gross examination of all organs included 397 adult anurans and 40 metamorphs representing five anuran species:Osteopilus septentrionalis(N=364),Rhinella marina(N=60),Lithobates sphenocephala(N=7),Anaxyrus terrestris(N=5)and Anaxyrus americanus(N=1).The gonads,liver,kidney and intestines were abnormal at a frequency of 87.4%.The few normal anurans(12.6%)were females and young male adults.We found a significant difference in organ abnormality type and f requency between sexes.Almost all f rog and toad males had testicular abnormality(92%)with only 6%with normal testes,whereas the female gonad abnormality was lower,at 41.6%.Hermaphroditism was found in both sexes at a frequency of 26.2%.The toads had a significantly higher frequency of hermaphroditism than the frogs.The toad hermaphroditism frequency was found to be 40%,whereas the frog hermaphroditism 23.3%.A hermaphrodite Cane toad male with a female phenotype coexisted with the normal male phenotype hermaphrodite.The fertility of 27 in situ pairs was assessed.The fertile testicular abnormal male and hermaphrodite pairs produced offspring with abnormal larval morphology.This information adds new evidence of the effect of chemicals on wild populations and the effect on non-target species which has always been underestimated.

Karyotypic analysis of intersexuality in Chinese from Taiyuan

Aim: To analyze the kayrotypic patterns of 33 cases of intersexuality in Chinese from Taiyuan, China in order tofurther clarify its mechanism of development and the interrelationship between karyotype and phenotypic sex. Meth-ods: High-resolution GTG-banding chromosome technique was used to analyze the karyotype patterns. Results:In these patients, 57.58% were male pseudohermaphrodites (46, XY), 18.18%, female pseudohermaphrodites (46,XX), 12.12%, true hemaphrodites, and 12.12%, other karyotypes, Although testes can be seen in 88.8% of kary-otypes with Y chromosome, 73.68% of the patients were of female social sex. In 42.82% of patients the social sex isin conformity with their karyotypes. There were 2 cases of male pseudohennaphrodites, where the sex chromosome wasnormal, but abnormalities were found in chromosomes 9, 13, or 14. Conclusion: Sex chromosomes determine thedirection of gonadal and sex differentiation, while the development of the normal gonad and extemal genitalia shouldhave the participation of many autosomal chromosomes as well.

Mating Type Alleles, Female Fertility and Genetic Diversity of Magnaporthe grisea Populations Pathogenic to Rice fromSome Asian Countries

Five hundred and twenty-two isolates of Magnaporthe grisea isolated from rice in 5 Asian countries were characterized for their mating type by crossing them with 4 hermaphroditic isolates(KA3 and TH12: MAT1.1; Guy11 and TH16: MAT1. 2). Among them, 41% were MAT1.1 and 25% were MAT1. 2. The remaining 34% did not produce perithecia with any of the 4 hermaphroditic testers. In Bangladesh, India, Nepal, Vietnam and in most provinces of China, both mating types were present. Only one mating type was found in 3 provinces and 1 city of China. Almost all the isolates had very low fertility, as they were in general female sterile and sometimes also male sterile. Hermaphroditic isolates were recovered from the 5 countries. In these countries, they represented between 13% and 75% of the isolates. In Zhejiang, Guizhou, Guangdong, Hunan, Yunnan and Hubei provinces of China, hermaphroditic isolates represented between 6% and 67%. The genetic diversity of 143 isolates from these countries and provinces, where hermaphroditic isolates had been collected, was analyzed using SCAR markers. Genetic diversity was high and population structure did not resemble classical clonal structure described in most rice growing regions. The existence of sexual reproduction in the field, localization of a center of diversity in China, and migration between countries were discussed in this paper.

PATHOLOGICAL CHARACTERISTICS OF GONADS IN NINE PATIENTS WITH TRUE HERMAPHRODITISM

The gonadal histopathology, and its correlation with the clinical features has been investigated in 9 true hermaphroditism patients, aged 5-21 yr. Seven of 9 patients had been raised as females, of which the chromosomal karyotype was 46XX in 5 cases, 46XX/46XY and 46XX/47XXY in 2 cases. Two of 9 pa- tients were raised as males, the chromosomal karyotypes being 46XX and 46XX/46XY. All 9 patients had testicular tissue excised, and biopsies of the conserved ovarian tissue were performed. Ovotestis was the most common form of the abnormal gonads; two of 9 patients had bilateral ovotestes, seven had unilateral ovotestes (5 in right side, 2 in left side). In seven patients with a unilateral ovotestis, 6 had a contralateral ovary and one had a contralateral testis. Microscopically, the ovarian tissue of 11 ovotestes, including 6 biopsies from contealateral ovaris, were normal, with many primordal follicles and a few growing follicles. In two of the patients, aged over 15 years, evidence of ovulation was observed. In comparison, the testicu- lar tissue of the ovotestis and the one left inguinal testis was histologically abnormal, with immature semi- niferous tubules, most of which filled with Sertoli cells only. Three of 9 patients married after surgical treatment. Two of these subsequently conceived and delivered of normal infants by cesarean section.

Sexual plasticity in bony fishes:Analyzing morphological to molecular changes of sex reversal

Sex reversal is one of the characteristic properties of sexual plasticity in bony fishes wherein both natural and induced sex change happens at various stages of life cycle in different species.Sex determination in gonochoristic species is genetically regulated,wherein the same sex is retained throughout their life span whereas hermaphrodites change their sex during development or adulthood.In sequential hermaphrodites,serial sex change occurs at different points of life cycle.Concurrently,synchronous hermaphrodites function as both the sexes during spawning.Other variables like temperature,pH and social factors can trigger sex reversal in teleost.Sex reversal through gene mutations and chemicals/hormones,including sex steroids,can be induced mostly at early developmental stages but natural sex reversal can occur at any time.Sex reversal mechanism shows morphological to molecular changes,which are ideal for identification of sex-specific gene markers.In fact,gonadal transdifferentiation occurs at the molecular level through differential expression of transcription factors and steroidogenic enzyme genes vis-a-vis hormones,thereby imparting phenotypic or structural changes.In addition,brain shows sexual dimorphism which is mostly consequential to gonadal sex development and occasionally either causative.The major breakthrough in this line is the identification of sex determining genes such as dmy/dmrt1Yb,gsdfY,sox3 in the Japanese medaka and amhY in Patagonian pejerrey.Incidentally,the induction of mono-sex population by favouring one sex due to sex-specific differences in growth is an important economic boom for aquaculture.This review comprehensively highlights key molecular factors involved in natural and induced sex reversal conditions to illustrate teleostean sexual plasticity and its application perspectives.

Sexual selection and hermaphroditic organisms： Testing theory

Sexual selection is widespread if not ubiquitous in hermaphroditic organisms. Although many phenomena that have been described as sexual selection in gonochores, （e.g. harem polygamy, multiple mating, elaborate courtship, even secondary sexual characters） can be found in some hermaphrodites, what is more interesting is the ways in which sexual selection in her- maphrodites may differ from dioecious taxa. In hermaphrodites, an individual＇s mating success includes its success from both sexual roles. Secondly, in many simultaneously hermaphroditic taxa there is strong evidence of sexual selection and yet the ope- rational sex ratio is 1：1, by definition. Many simultaneous hermaphrodites have elaborate courtship and genital anatomy, suggest- ing sexual selection plays an important role in reproductive success. Sperm competition and cryptic female choice mean that the number of mates acquired is not necessarily a predictor of reproductive success. Even in simultaneous hermaphrodites with re- ciprocal mating, variance in reproductive success through the male role and through the female role may differ in a population. Moreover hermaphrodites may choose to emphasize one sexual role over the other. Data suggest that the preferred role varies in hermaphrodites, which creates an opportunity to test fundamental predictions and assumptions of sexual selection theory. Hermaphrodites may vary their emphasis on one sexual role over the other either developmentally or behaviorally in response to environmental or social parameters. How they use this capability in acquiring more or higher quality mates still requires study

Mitochondrial selfish elements and the evolution of biological novelties

We report the present knowledge about RPHM21, a novel male-specific mitochondrial protein with a putative role in the paternal inheritance of sperm mitochondria in the Manila clam Ruditapes philippinarum, a species with doubly uniparental inheritance of mitochondria （DUI）. We review all the available data on rphm21 transcription and translation, analyze in detail its female counterpart, RPHF22, discuss the homology with RPHM21, the putative function and origin, and analyze their polymorphism. The available evidence is compatible with a viral origin of RPHM21 and supports its activity during spermatogenesis. RPHM21 is progressively accumulated in mitochondria and nuclei of spermatogenic cells, and we hypothesize it can influence mitochondrial inheritance and sex- ual differentiation. We propose a testable model that describes how the acquisition of selfish fea- tures by a mitochondrial lineage might have been responsible for the emergence of DUI, and for the evolution of separate sexes （gonochorism） from hermaphroditism. The appearance of DUI most likely entailed the invasion of at least 1 selfish element, and the extant DUI systems can be seen as resolved conflicts. It was proposed that hermaphroditism was the ancestral condition of bivalves, and a correlation between DUI and gonochorism was documented. We hypothesize that DUI might have driven the shift from hermaphroditism to gonochorism, with androdioecy as transi- tion state. The invasion of sex-ratio distorters and the evolution of suppressors can prompt rapid changes among sex-determination mechanisms, and DUI might have been responsible for one of such changes in some bivalve species. If true, DUI would represent the first animal sex-determination system involving mtDNA-encoded proteins.

Floral biology and pollination mechanisms of four Mexico-endemic Fuchsia species with contrasting reproductive systems

Aims The evolution of the outstanding variation of reproductive systems in angiosperms has been considered an important driver of line-age diversification.Closely related hermaphroditic and dioecious species with biotic pollination provide the opportunity to study and compare traits related to pollinator attraction and their con-sequences on reproductive components.A higher predictability of pollination syndromes is expected in dioecious species,which are dependent on pollinators,than in self-compatible hermaphroditic taxa.Dioecious species may suffer pollen limitation depending on the quality of floral rewards and the kind and abundance of pollina-tors,whereas no pollen limitation is expected in hermaphroditic spe-cies with autonomous self-pollination.Additionally,in the absence of pollen limitation,more or better seeds are expected in dioecious species,according to the sexual specialization hypothesis.Methods In natural populations of the hermaphroditic Fuchsia fulgens and Fuchsia arborescens and dioecious Fuchsia parviflora and Fuchsia obconica,all endemic to Mexico,we first described flower phenol-ogy,flower production and longevity and nectar volume and concen-tration.Then,we evaluated the correspondence between floral visitors and pollination syndromes.In hermaphrodite plants,we determined the level of herkogamy and the potential for autonomous self-pollina-tion.Finally,we evaluated the effect of pollen limitation on fruit set and seed number and assessed seed germination for all species.Important Findings In contrast to our prediction,dioecious species did not show a higher correspondence between pollination syndromes and floral visitors than did hermaphrodites;however,male flowers exhib-ited a higher correspondence than female flowers.No pollen limitation was detected in dioecious species,for which visitation rate did not differ between male and female flowers.The her-maphroditic F.fulgens showed pollen limitation for seed number,despite the presence of autonomous selfing.Fruit set from auton-omous pollination was higher in F.arborescens,which showed a lower level of herkogamy compared with F.fulgens.Finally,dioecious species produced fewer but heavier seeds compared with hermaphrodite species.Although Fuchsia is classified as an outcrossing genus,both hermaphroditic species showed autono-mous self-pollination.The heavier but lower number of seeds per fruit in dioecious species may be related to the more efficient resource allocation expected from sexual specialization.This could play an important role in the evolution of dioecy;however,a comparative phylogenetic approach is required to confirm this hypothesis.