Sexual Mating Research Articles

Molecular phylogeny of hinge-beak shrimps (Decapoda: Caridea:RhynchocinetesandCinetorhynchus) and allies: a formal test of familiar and generic monophyly using a multilocus phylogeny

The Rhynchocinetidae (‘hinge-beak’ shrimps) is a family of marine caridean decapods with considerable variation in sexual dimorphism, male weaponry, mating tactics, and sexual systems. Thus, this group is an excellent model with which to analyse the evolution of these important characteristics, which are of interest not only in shrimps specifically but also in animal taxa in general. Yet, there exists no phylogenetic hypothesis, either molecular or morphological, for this taxon against which to test either the evolution of behavioural traits within the Rhynchocinetidae or its genealogical relationships with other caridean taxa. In this study, we tested (1) hypotheses on the phylogenetic relationships of rhynchocinetid shrimps, and (2) the efficacy of different (one-, two-, and three-phase) methods to generate a reliable phylogeny. Total genomic DNA was extracted from tissue samples taken from 17 species of Rhynchocinetidae and five other species currently or previously assigned to the same superfamily (Nematocarcinoidea); six species from other superfamilies were used as outgroups. Sequences from two nuclear genes (H3 and Enolase) and one mitochondrial gene (12S) were used to construct phylogenies. One-phase phylogenetic analyses (SATe-II) and classical two- and three-phase phylogenetic analyses were employed, using both maximum likelihood and Bayesian inference methods. Both a two-gene data set (H3 and Enolase) and a three-gene data set (H3, Enolase, 12S) were utilized to explore the relationships amongst the targeted species. These analyses showed that the superfamily Nematocarcinoidea, as currently accepted, is polyphyletic. Furthermore, the two major clades recognized by the SATe-II analysis are clearly concordant with the genera Rhynchocinetes and Cinetorhynchus, which are currently recognized in the morphological-based classification (implicit phylogeny) as composing the family Rhynchocinetidae. The SATe-II method is considered superior to the other phylogenetic analyses employed, which failed to recognize these two major clades. Studies using more genes and a more complete species data set are needed to test yet unresolved inter- and intrafamilial systematic and evolutionary questions about this remarkable clade of caridean shrimps. © 2014 The Linnean Society of London

Experimental male size manipulation in Polistes dominula paper wasps: being the right size

In previous studies on Polistes dominula paper wasps, male size affects both mating success and territorial strategy. Larger males occupy exclusive territories at leks, i.e. landmarks where they achieve most copulations (Residents), while smaller males search for females in sub-optimal locations across territories as Transients. We here observed spatial and mating behaviour of a selected size-bimodal population of males, caught at leks and released in semi-natural conditions. Residents, mainly Large males, were more successful in sexual interactions with virgin females than Transients. Residents also engaged in ‘mate guarding’, reported here for the first time. On the other hand, some Small males achieved copulations inside their own territories, at foraging sites or by grasping females and falling on the ground. Both tactics of mate access – patrolling a territory for perched females or intercepting females – were successful, the former more than the latter, whereas size itself was irrelevant to sexual performance and mating success, regardless of our size-bimodal sample. Moreover, we carried out morphological analysis of male reproductive apparatus. Males with larger accessory glands, directly involved in reproductive success in many insects, mated more than males with smaller accessory glands, regardless of male body size.

Mechanism of mate detection in parasitoid wasps: sound and vibratory cues change with the developmental progress of future mates inside host pupal cases

AbstractInsects including parasitoid wasps use acoustic and vibratory signals in the context of sexual communication, mate recognition, courtship and mating. Males of the parasitoid wasp Pimpla disparis Viereck (Hymenoptera: Ichneumonidae) detect insect host pupae parasitized by a conspecific female, learn their location, visit them repeatedly and remain on or near them when the prospective mate nears emergence. In the present study, the acoustic and vibratory cues that males exploit to detect the presence and track the developmental progress of a future mate inside a host pupal case are investigated. Responses are acquired from developing parasitoids (DePa) by airborne sound and laser Doppler vibrometer recordings, after gently stimulating each of 20 wax moth host pupae with a paintbrush on days 1–23 post parasitism. Sound and vibratory cues produced by DePa are detectable from day 7 onward and relate mostly to spinning movements. Parameters of sound and vibratory cues (amplitude, dominant frequency, upper limit of frequency band) change significantly over time and thus could ‘inform’ a visiting adult male about the stage of development of DePa. Adult males antennating a parasitized pupa and flying around it also induce vibrations, which in turn may inform DePa about the presence of a male. There is no experimental evidence for true signalling and rapid information exchange between DePa and adult males. Delaying reply signals may help DePa avoid attacks by illicit receivers of such signals, including female (hyper)parasitoids and invertebrate predators.

Assessment of ovarian activity in captive goral (Naemorhedus griseus) using noninvasive fecal steroid monitoring

To date, there is no information on gonadal steroidogenic activity of female goral (Naemorhedus griseus), a threatened species of Thailand. Captive goral populations have been established to produce animals for ex situ conservation and reintroduction, but as yet none are self-sustaining. The objectives of the present study were to (1) determine the influence of season on ovarian steriodogenic function; and (2) examine the relationship between gonadal hormone excretion and sexual behaviors throughout the year. Fecal samples were collected 5 to 7 days/wk for 15 months from 8 adult females housed at Omkoi Wildlife Breeding Center in Thailand and analyzed for ovarian steroid metabolites using validated enzyme immunoassays. Observations of sexual behaviors and mating were conducted each morning for 30 min/session. Based on fecal estrogen and progestagen metabolite concentrations, the overall estrous cycle length was about 21 days, with a 2- to 3-day follicular phase and an 18- to 20-day luteal phase. Sexual behaviors, most notably tail-up, increased for 2 to 3 days during the time estrogens were elevated during mating. Fecal progestagens were elevated during luteal phases and increased further during gestation, which lasted approximately 7 months. The lactation period was 5 months, and females were anestrus for 2 to 5 of those months, with the exception of one that cycled continuously throughout. Two females conceived around 2 months postpartum and so were pregnant during lactation. Birth records over the past 21 years indicated young are born throughout the year. This combined with the hormonal data suggests that female gorals are not strongly seasonal, at least in captivity, although there was considerable variation among females in estrogen and progestagen patterns. In conclusion, fecal steroid metabolite monitoring is an effective means of assessing ovarian function in this species and will be a useful tool for breeding management and planned development of assisted reproductive techniques such as artificial insemination and embryo transfer.

Genetics of decayed sexual traits in a parasitoid wasp with endosymbiont-induced asexuality.

Trait decay may occur when selective pressures shift, owing to changes in environment or life style, rendering formerly adaptive traits non-functional or even maladaptive. It remains largely unknown if such decay would stem from multiple mutations with small effects or rather involve few loci with major phenotypic effects. Here, we investigate the decay of female sexual traits, and the genetic causes thereof, in a transition from haplodiploid sexual reproduction to endosymbiont-induced asexual reproduction in the parasitoid wasp Asobara japonica. We take advantage of the fact that asexual females cured of their endosymbionts produce sons instead of daughters, and that these sons can be crossed with sexual females. By combining behavioral experiments with crosses designed to introgress alleles from the asexual into the sexual genome, we found that sexual attractiveness, mating, egg fertilization and plastic adjustment of offspring sex ratio (in response to variation in local mate competition) are decayed in asexual A. japonica females. Furthermore, introgression experiments revealed that the propensity for cured asexual females to produce only sons (because of decayed sexual attractiveness, mating behavior and/or egg fertilization) is likely caused by recessive genetic effects at a single locus. Recessive effects were also found to cause decay of plastic sex-ratio adjustment under variable levels of local mate competition. Our results suggest that few recessive mutations drive decay of female sexual traits, at least in asexual species deriving from haplodiploid sexual ancestors.

Molecular characterization and functional analysis of a putative sex-peptide receptor in the tobacco cutwormSpodoptera litura(Fabricius, 1775) (Lepidoptera: Noctuidae)

The sex-peptide receptor (SPR) acts in Drosophila females to detect male sex-peptide (SP) and trigger changes in female behaviour. Further study on SPR and its ligand family from different taxa will not only provide insight into ligand–receptor coevolution but also facilitate finding new approaches for pest control. Our previous studies on the tobacco cutworm Spodoptera litura (Fabricius, 1775) showed that mating usually results in marked changes in female behaviour and determined that factors from male accessory gland (MAG) secretions play a key role in such switches in females after mating. In the present study, we report the cloning of a transcript encoding a G-protein-coupled receptor from S. litura. This 3 kb transcript contains an ORF encoding a protein of 421 amino acids that shared significant amino acid identity to the SPR identified in Drosophila. Real-time PCR showed that the expression levels of the receptor in adults correlate well with the process of sexual maturation and mating rates; mating resulted in distinct sexual dimorphic differences in gene expression. Our results suggest that this gene is involved in mediating reproductive behaviour in adult moths. To test the hypothesis, we further studied the possible function of this receptor (SplSPR) on mediating female post-mating behaviour by using RNA interference (RNAi) and treatment with MAG secretions. RNAi reduced the expression levels of SplSPR by 65–88% and significantly prevented the effect of MAG secretions. Injection of MAG secretions causes normal virgin females to behave as though they had mated (they are sexually unreceptive and start to lay eggs), whereas SPR RNAi females fail to respond to MAG factors and continue to show virgin behaviours (lay very few eggs and copulate readily). These results support the hypothesis that the SplSPR functions in mediating female post-mating behaviour and the existence of an SP-like ligand in MAG secretions in S. litura.

MP43-05 EFFECT OF BUPROPION AND TADALAFIL COMBINATION THERAPY IN FEMALE RAT HYPOACTIVE SEXUAL DESIRE DISORDER MODEL

You have accessJournal of UrologySexual Function/Dysfunction/Andrology: Basic Research I1 Apr 2014MP43-05 EFFECT OF BUPROPION AND TADALAFIL COMBINATION THERAPY IN FEMALE RAT HYPOACTIVE SEXUAL DESIRE DISORDER MODEL Hana Yoon, Hyun-suk Yoon, Bong-suk Shim, Young-yo Park, Woo-sik Chung, Dong-hyun Lee, and Kwang-hyun Kim Hana YoonHana Yoon More articles by this author , Hyun-suk YoonHyun-suk Yoon More articles by this author , Bong-suk ShimBong-suk Shim More articles by this author , Young-yo ParkYoung-yo Park More articles by this author , Woo-sik ChungWoo-sik Chung More articles by this author , Dong-hyun LeeDong-hyun Lee More articles by this author , and Kwang-hyun KimKwang-hyun Kim More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.1162AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail Introduction and Objectives Hypoactive sexual desire disorder (HSDD) in female sexual dysfunction takes significant portion of female sexual dysfunction, but its treatment modalities are few. Bupropion is known to have increase sexual desire in serotonin reuptake inhibitor(SSRI) induced HSDD and tadalafil is well known PDE5 inhibitor. In this study, we aimed to investigate the efficacy and safety of combination treatment of bupropion and tadalafil in female rat HSDD model. Methods Bilateral oophorectomized female Sprague-Dawley rats were used as sub-primed HSDD model. In this model, after 2 weeks of oophorectomy, estradiol(2ug) was injected subcutaneously (SQ) before every sexual mating. Experimental groups are VH (Vehicle, injection of sesame oil), B (Bupropion 20mg/Kg, daily, SQ), P (tadalafil 2mg/kg, daily, PO), PB (Bupropion 20mg/Kg SQ with tadalafil 2mg/kg PO, daily) . At baseline, 7th day, and 14th day of drug administration, sexual behaviors were observed in specially designed mating cage. Sexual behaviors were analyzed as proceptive behavior(darts and hops), receptive behavior(lordosis), paced mating behavior(mean time of exit (sec/min). Results Drug administered group(B,P, and PB) were all significantly improved sexual behavior analysis compared with VH group. At 14th day of drug administration, combination treatment group(PB) showed more significant improvement in proceptive, receptive behaviors and less avoidance time than other three(VH, B, and P) groups(p<0.01 by ANOVA). There were no drug related death or adverse reactions. Conclusions In female rat HSDD model, combination treatment of bupropion and tadalafil showed significant improvement of sexual behavior than single drug treatment with time-correlation. This supports that combination of bupropion and tadalafil may have beneficial effect on human HSDD. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e478 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Hana Yoon More articles by this author Hyun-suk Yoon More articles by this author Bong-suk Shim More articles by this author Young-yo Park More articles by this author Woo-sik Chung More articles by this author Dong-hyun Lee More articles by this author Kwang-hyun Kim More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Effect of GnRH analogs in postnatal domestic cats

The aim of this study was to reproductively assess the clinical and hormonal effects of a GnRH agonist (AG) and an antagonist (AN) administered during the postnatal period in domestic cats. Forty-eight male and female postnatal kittens were randomly assigned to deslorelin acetate 1.6 mg subcutaneous (AG; n = 16), acyline 33 μg/100 g subcutaneous weekly for 3 months (AN; n = 16), or control (CO; n = 16) which remained untreated. The cats were followed up (behavioral observation, physical examination, fecal sexual steroid determinations, mating test, and pregnancy diagnosis) up to puberty. Puberty was delayed (weeks) in the AG animals (62.9 ± 3.5; P < 0.01) but not in the AN (15.5 ± 1.7; P > 0.05) when they were compared with CO kittens (13.4 ± 0.4). Fifteen (15/16) of the AN and CO animals, and only 11 of 16 cats of the AG group were fertile (P > 0.1). No differences were found in body weight (P > 0.1) and measurements (P > 0.1), libido (P > 0.1) and in the appearance of side effects (P > 0.1; except a pyometra in an AG female) among groups. In both AG- and AN-treated males (testosterone; P < 0.01) and females (estradiol-17β; P < 0.01) fecal hormone concentrations were lower than in CO group during the first five postnatal weeks but not later. It is concluded that the neonatal administration of these AG and AN decreased fecal sexual steroids during the first postnatal weeks causing, the agonists but not the antagonist, a significant, reversible delay in puberty appearance.

Circadian Release of Male-Specific Components of the Greater Date Moth, Aphomia (Arenipses) Sabella, Using Sequential SPME/GC/MS Analysis

The greater date moth (GDM), Aphomia sabella Hampson (Lepidoptera: Pyralidae: Galleriinae), is a serious pest of date palms, Phoenix dactylifera. The release of volatiles from both males and females was investigated using sequential SPME/GC/MS analysis. Males release a complex mixture of compounds in a circadian rhythm during the night between 03:00 and 05:00 hr. Six compounds were identified: benzaldehyde, sulcatol (6-methyl-5-hepten-2-ol), geranyl acetone [(E)-6,10-dimethyl-5,9-undecadien-2-one], phenylacetaldehyde, 2-phenylpropenal, and (R)-fuscumol [(R)-(E)-6, 10-dimethyl-5, 9-undecadien-2-ol]. Benzaldehyde, sulcatol, and geranyl acetone were found only in trace amounts. These compounds were in glands located in the forewing of males only. Small amounts of acetoin and 2,3-butanediol were found sporadically in the SPME/GC/MS analyses of volatiles from females, and these compounds probably originate from microorganisms. This is the first finding of a circadian release of male-specific compounds in moths. GC/EAD analyses with synthetic standards of compounds released by males showed that the female antenna is stimulated by all six compounds, while the male antenna responded only to phenylacetaldehyde. A possible pheromonal role for the male-specific compounds is suggested by the circadian rhythm of their release and the EAD response of females to them. However, trapping tests with the main male-specific compounds in screen cages in the laboratory or in the field did not reveal any significant behavioral responses from females or males. Copulation in the laboratory was observed only in the presence of date palm tissue, thus suggesting that sexual communication and mating of GDM moths probably occurs in the crown of date palms.

Host-shift effects on mating behavior and incipient pre-mating isolation in seed beetle

Mating behavior is based on communication among mates and includes both sexual signaling and mating preferences. In phytophagous insects, shift to a novel host will expose associated traits to novel selection regimes and eventually cause assortative mating and sexual isolation between populations inhabiting diverse host plants. We investigated the relationship between short- and long-term changes in mating systems on Acanthoscelides obtectus. Mating preferences were evaluated using measures of copulation frequency in mating trials within and among populations and by measuring time spent in sexual interactions prior to copulation. Sexual signaling was previously analyzed by chemical detection of contact pheromones (i.e., cuticular hydrocarbons [CHCs]), and these results were used in this study. Laboratory populations evolved for 50 generations either on the optimal host (common bean) or on the suboptimal host (chickpea). To determine short-term effects, subsets of individuals from each population were exposed to the alternative host for 1 generation. We revealed higher level of indiscriminate mating in populations, which evolved on the suboptimal host. Males from these populations spent less time in assessing mates although they had the ability to discriminate between signals. Short-term larval experience on the suboptimal host also decreased selectivity of mates. The results imply that plastically induced reduction in mate discrimination, after a shift to suboptimal host, may have been canalized through long-term genetic changes underlying behavioral development. Significant reproductive isolation between the 2 sets of populations was revealed regardless of the short-term host treatment.

EARLY EVOLUTION OF SEXUAL DIMORPHISM AND POLYGYNY IN PINNIPEDIA

Sexual selection is one of the earliest areas of interest in evolutionary biology. And yet, the evolutionary history of sexually dimorphic traits remains poorly characterized for most vertebrate lineages. Here, we report on evidence for the early evolution of dimorphism within a model mammal group, the pinnipeds. Pinnipeds show a range of sexual dimorphism and mating systems that span the extremes of modern mammals, from monomorphic taxa with isolated and dispersed mating to extreme size dimorphism with highly ordered polygynous harem systems. In addition, the degree of dimorphism in pinnipeds is closely tied to mating system, with strongly dimorphic taxa always exhibiting a polygynous system, and more monomorphic taxa possessing weakly polygynous systems. We perform a comparative morphological description, and provide evidence of extreme sexual dimorphism (similar to sea lions), in the Miocene-aged basal pinniped taxon Enaliarctos emlongi. Using a geometric morphometric approach and combining both modern and fossil taxa we show a close correlation between mating system and sex-related cranial dimorphism, and also reconstruct the ancestral mating system of extant pinnipeds as highly polygynous. The results suggest that sexual dimorphism and extreme polygyny in pinnipeds arose by 27 Ma, in association with changing climatic conditions.

Sexual dimorphism and mating behavior in Anomala testaceipennis.

The beetle, Anomala testaceipennis Blanchard (Coleoptera: Scarabaeidae), occurs in central-western Brazil where larvae feed on the roots of plants causing damage. This research aimed to study sexual dimorphism and mating behavior of A. testaceipennis . Adults of A. testaceipennis were collected with light traps in the experimental area of the State University of Mato Grosso do Sul, in Aquidauana. Laboratory experiments were performed to describe copulation behavior and adult morphology of males and females. In males the last abdominal segment has a pronounced constriction, which is absent in females, and the male’s last segment of the first pair of legs has a ventral projection, which is poorly developed in females. The mating activities of adults begin soon after sunset, when adults leave the soil and fly. When the male encounters a female, he touches her with antennae and tarsi. If accepted, the male climbs on the female and remains on her back, and soon after the copulation begins. When the female does not accept the male for mating, she moves rapidly and can roll on the ground, and by so removing the male. In the field, adults feed and mate on bloomed trees of Oiti, Licania tomentosa Benth (Malpighiales: Chrysobalanaceae) and Louro, Cordia glabrata Martius (Boraginaceae). In trees without inflorescences no adults of this species were found.

The Neotropical Genus Austrolebias: An Emerging Model of Annual Killifishes

Annual fishes are found in both Africa and South America occupying ephemeral ponds that dried seasonally. Neotropical annual fishes are members of the family Rivulidae that consist of both annual and non-annual fishes. Annual species are characterized by a prolonged embryonic development and a relatively short adult life. Males and females show striking sexual dimorphisms, complex courtship, and mating behaviors. The prolonged embryonic stage has several traits including embryos that are resistant to desiccation and undergo up to three reversible developmental arrests until hatching. These unique developmental adaptations are closely related to the annual fish life cycle and are the key to the survival of the species. Most of the available data on Neotropical annual fishes derive from studies on the genus Austrolebias. Herein, we review and summarize the available data on the evolution, reproduction strategy, developmental biology and conservation status of these Neotropical fishes.

Male size does not correlate with fertilization success in two bufonid toads that show size-assortative mating

Abstract We examined sexual size dimorphism (SSD), mating pattern, fertilization efficiency and female reproductive traits in two bufonid toads (Bufo gargarizans and Duttaphrynus melanostictus) to test the idea that importance of male body size for egg fertilization success depends on the mating pattern. Female-biased SSD was evident only in D. melanostictus. Female B. gar-garizans laid fewer larger eggs nearly three months earlier than did female D. melanostictus. Fertilization efficiencies on average were higher in B. gargarizans (95%) than in D. melanostictus (91%). Though differing in the degree of SSD, body size, breeding season, clutch size, egg size and fertilization efficiency, the two toads were similar in four aspects: (1) both showed size-assortative mating; (2) females did not tradeoff egg size against egg number; (3) male size, clutch size and clutch dry mass were greater in male-larger than in female-larger pairs after accounting for female snout-vent length (SVL); and (4) the ratio of male to female SVL did not affect fertilization efficiency. Our data show that: (1) a female preference for large males is likely not important in terms of egg fertilization success; (2) a male preference for large females is likely important because larger females are more fecund; and (3) size-assortative mating arises from a male preference for large females. Our study demonstrates that male size is not always important for egg fertilization success in anurans that show size-assortative mating.

The role of MADS-box transcription factors in secondary metabolism and sexual development in the maize pathogen Fusarium verticillioides

MADS-box transcription factors (TFs) regulate functionally diverse gene targets in eukaryotes. In select ascomycetes, MADS-box TFs have been shown to play a role in virulence, and vegetative and sexual development. Here, we characterized Fusarium verticillioides MADS-box TFs, Mads1 and Mads2, in terms of their roles in secondary metabolism and sexual mating. Sequence analyses showed that MADS1 and MADS2 encode TFs with a SRF-type dimerization domain and a MEF2-type dimerization domain, respectively. The MADS1 and MADS2 knockout mutants (Fmt1 and Fmt2 strains, respectively) exhibited decreased vegetative growth and FB1 production when compared to the wild-type. Fmt1 showed reduced expression of 14 polyketide synthase (PKS) genes present in the organism, whereas Fmt2 did not display a change in PKS gene expression. Significantly, the deletion of MADS1 and MADS2 in the MAT1-2 genotype (Fmt4 and Fmt5 strains, respectively) led to strains that failed to produce perithecia and ascospores when crossed with the MAT1-1 wild-type strain. Notably, deletion of either gene did not have an effect on the ability of the fungus to colonize maize stalk or kernels. FB1 production and PKS expression data suggest that Mads1 is a broad regulator of secondary metabolism in F. verticillioides, and may target regulons upstream of Mads2 to influence FB1 production. In addition, MADS-box TFs in F. verticillioides play a critical role in the perithecia development.

Rapid adaptation of microalgae to bodies of water with extreme pollution from uranium mining: An explanation of how mesophilic organisms can rapidly colonise extremely toxic environments

Extreme environments may support communities of microalgae living at the limits of their tolerance. It is usually assumed that these extreme environments are inhabited by extremophile species. However, global anthropogenic environmental changes are generating new extreme environments, such as mining-effluent pools of residual waters from uranium mining with high U levels, acidity and radioactivity in Salamanca (Spain). Certain microalgal species have rapidly adapted to these extreme waters (uranium mining in this area began in 1960). Experiments have demonstrated that physiological acclimatisation would be unable to achieve adaptation. In contrast, rapid genetic adaptation was observed in waters ostensibly lethal to microalgae by means of rare spontaneous mutations that occurred prior to the exposure to effluent waters from uranium mining. However, adaptation to the most extreme conditions was only possible after recombination through sexual mating because adaptation requires more than one mutation. Microalgae living in extreme environments could be the descendants of pre-selective mutants that confer significant adaptive value to extreme contamination. These “lucky mutants” could allow for the evolutionary rescue of populations faced with rapid environmental change.

Parasexuality and Ploidy Change in Candida tropicalis

Candida species exhibit a variety of ploidy states and modes of sexual reproduction. Most species possess the requisite genes for sexual reproduction, recombination, and meiosis, yet only a few have been reported to undergo a complete sexual cycle including mating and sporulation. Candida albicans, the most studied Candida species and a prevalent human fungal pathogen, completes its sexual cycle via a parasexual process of concerted chromosome loss rather than a conventional meiosis. In this study, we examine ploidy changes in Candida tropicalis, a closely related species to C. albicans that was recently revealed to undergo sexual mating. C. tropicalis diploid cells mate to form tetraploid cells, and we show that these can be induced to undergo chromosome loss to regenerate diploid forms by growth on sorbose medium. The diploid products are themselves mating competent, thereby establishing a parasexual cycle in this species for the first time. Extended incubation (>120 generations) of C. tropicalis tetraploid cells under rich culture conditions also resulted in instability of the tetraploid form and a gradual reduction in ploidy back to the diploid state. The fitness levels of C. tropicalis diploid and tetraploid cells were compared, and diploid cells exhibited increased fitness relative to tetraploid cells in vitro, despite diploid and tetraploid cells having similar doubling times. Collectively, these experiments demonstrate distinct pathways by which a parasexual cycle can occur in C. tropicalis and indicate that nonmeiotic mechanisms drive ploidy changes in this prevalent human pathogen.

Mating type genes and cryptic sexuality as tools for genetically manipulating industrial molds

A large number of molds serve as producer strains for the industrial production of pharmaceuticals, foods, or organic chemicals. To optimize strains for production processes, conventional strain development programs use random mutagenesis and, more recently, recombinant technologies to generate microbial strains with novel and advantageous properties. The recent detection of mating type genes in fungal production strains and the discovery of cryptic sexuality in presumably asexual fungi open up novel strategies for generating progeny with new, as yet unobserved properties. Mating type genes, which can be considered as "sex genes," not only direct sexual development but also regulate a broad range of fungal secondary metabolites. In addition, they control hyphal morphology, which has a direct impact on production processes that are often conducted in huge fermenter tanks. Here, we survey the occurrence and function of mating type genes that have been discovered in a wide range of industrial fungal producer strains. The possibility to obtain progeny from industrial producers by sexual mating provides an exciting alternative to conventional strain improvement programs aiming to generate optimized recombinant production strains.

Evidence for a dioecious mating system in Early JurassicHardapestheria maxwelligen. et sp. nov. (Crustacea, Branchiopoda, Spinicaudata) from the Kalkrand Formation of Namibia

A new spinicaudatan (clam shrimp), Hardapestheria maxwelli gen. et sp. nov., is described from the Jurassic Kalkrand Formation of central Namibia. Specimens were collected from a sedimentary interbed within a succession of flood basalts. These are the first spinicaudatans to be described from the Jurassic of south-western Africa. The new taxon is assigned to the family Eosestheriidae based on the combination of punctae and radial ornamentation on the carapace. Ornamentation on the growth bands in H. maxwelli differs from other eosestheriid genera because the punctate ornamentation is not restricted to the dorsal region of the carapace. Instead, all growth bands include a proximal region with punctae even though the distal portion of each growth band may exhibit anastomosing lirae. Among well-documented Mesozoic spinicaudatan genera, Hardapestheria is most closely related to Carapacestheria from the contemporaneous Kirkpatrick Basalt of Antarctica and Yanjiestheria from the Early Cretaceous of China. Hardapestheria maxwelli displays sexual dimorphism, which can be definitively related to a dioecious mating system with discrete male and female individuals. Review of additional early members of the Eosestheriidae suggests that the maintenance of two discrete sexes was the ancestral state for the clade. The ability to discriminate sexual mating system type unambiguously is rare in fossils, and this new species sheds light on the relationship between environmental stability and mating system evolution.

Sexual Recognition and Mating Behavior of the Populus Longhorned Beetle, Batocera lineolata (Coleoptera: Cerambycidae)

We studied the sexual recognition and mating behavior of B. lineolata by video tracking capture system (EthoVision 3.1) and field observation, in order to get some fundamental information for the effective control of Batocera lineolata Chevrolat (Coleoptera: Cerambycidae) and enrich the reproductive behavior of the insect. Result showed that, during the encountering, the intersection time of two tracks and net relative movements for the female-male group were longer than for the female-female group or the male-male group; while the reaction time was shorter than the latters. A complete mating of B. lineolata included three stages, i.e. (ⅰ) pair-bonding (ⅱ) mating attempt and ejaculation (ⅲ) post-copulatory guarding. The average time of pair-bonding is 2.16 min, and 10.28 min, 5.37 min for mating and post-copulatory guarding, respectively. In mating experiments with different sex ratios, the mating number fluctuated regularly, and it was greatly different in mating number for male or female individuals. The virgin female or male, spent more total ejaculation time than mated ones. Higher mating rates were observed on the host plant than on the open ground. The mating behavior in the field test was similar to results from the laboratory experiment.