Pampas deer (Ozotoceros bezoarticus) courtship and mating behavior

Background

Pampas deer, Ozotoceros bezoarticus (Linnaeus 1758), is a South American grazing deer categorized as "near threatened". However, knowledge about pampas deer behavior including courtship and mating is scarce and incomplete. The aim of this study was to characterize the courtship and mating behavior of the pampas deer (Ozotoceros bezoarticus), an endangered species from South America.

Methods

We performed focal observations of 5 males allocated at the Estación de Cría de Fauna Autóctona Cerro Pan de Azúcar, Uruguay, 4 times a day from 5 to 20 minutes each time on a daily basis from February to May. During that period we recorded all courtship and mating behaviors, as well as quantified the frequency of the specific behaviors shown. As mating were rarely observed, we recorded that behavior when it was observed in the context of other studies performed in the same population during the following 2 years.

Results

During the observation period we recorded 928 courtships and 5 mating periods. In addition, we recorded 10 more matings performed during other studies, totaling 15. The duration of each mating calculated from the 15 recordings was 3.9 ± 0.4 s, and the total period of female receptivity (from first to last mating acceptance) was 8.2 ± 1.1 min. Main observed courtship behaviors in males were “chase” and “ostentation”, while the most observed close to mating were “chinning”, “raised head” and “anogenital sniffing”. The most observed behaviors in females during the mating period were “vulva exhibition” and “move away”.

Conclusion

This is the first detailed report in pampas deer mating behavior. Estrus lasted only 8 min accepting only 3 short copulations per estrus. However, female behavior during courtship can be characterized as highly proceptive.     

Sry-negative XX sex reversal in a family of Norwegian Elkhounds

Two related female Norwegian Elkhounds were evaluated at 6 and 8 months of age for enlarged clitori. Both had a 78 XX karyotype. Histology of their internal reproductive tracts demonstrated 1 to be an XX true hermaphrodite with bilateral ovotestes and the other to be an XX male with bilateral aspermatogenic testes. Polymerase chain reaction-based tests of genomic DNA showed that both dogs lacked Sry, the testis-determining gene. Pedigree analysis was consistent with an autosomal recessive mode of inheritance, as has been reported in the American Cocker Spaniel and the German Shorthaired Pointer. This is the 1st reported case of familial Sry-negative XX sex reversal in the Norwegian Elkhound. A summary of 34 previously unreported cases of dogs with masculinized external genitalia and a normal 78 XX karyotype seen from 1980 to 1997 is given.     

高山红景天不同性别植株形态的比较研究

[目的]进一步了解高山红景天不同性别间的形态特点。[方法]以栽培高山红景天和野生高山红景天为材料,进行高山红景天不同性别植株形态的比较研究。[结果]结果表明,高山红景天不同性别间形态有一定的差异,株高雌株略高于雄株,主茎叶片数雄株多于雌株．叶片形态雄株比雌株狭长且薄、两性植株叶片较宽,茎粗雄株比雌株细,茎数雄株明显多于雌株,地下部根茎粗、根茎长和根茎数等性状雄株均大于雌株。[结论]该研究为高山红景天的性别分化机理、组织培养和遗传育种研究提供基础理论依据。     

Gender determination in the Paiche or Pirarucu (<Emphasis Type="Italic">Arapaima gigas</Emphasis>) using plasma vitellogenin, 17β-estradiol,and 11-ketotestosterone levels

Arapaima gigas is an air-breathing giant fish of Amazonian rivers. Given its great economic and cultural importance, the aquaculture development of this species represents an evident solution to face the decline of wild populations. In captivity, reproduction occurs generally in large earthen ponds where stocks of a few tens of brooders are maintained together at the beginning of the rainy season (December–March in the Peruvian Amazon). Fry production relies on the spontaneous formation of male and female pairs, which build a nest, delimit a territory and guard the offspring for at least 20 days from other congeners and predators. However, as sex determination of A. gigas is not possible by morphological criteria, it is very difficult to optimize reproduction conditions and fry production in each pond, which seriously hampers the culture of this species. This situation prompted us to develop sexing methodologies based on (1) the detection of female specific plasma Vitellogenin (Vtg) using an enzyme immuno assay (EIA), and (2) the determination of plasma 17β-estradiol and 11-ketotestosterone levels for immature specimens. The Vtg purification was performed by electro-elution after polyacrilamide gel electrophoresis (PAGE) from plasma of 17β-estradiol treated A. gigas juveniles. Two different Vtg molecules were isolated, (Vtg₁ and Vtg₂) with 184 and 112 kDa apparent molecular masses, respectively, and two antibodies were raised in rabbits for each Vtg molecule. Adult fish were 100% accurately sexed by Vtg EIA, while 100% of immature fish and 95% of adults were accurately sexed by 17β-Estradiol and 11-Ketestosterone ratios. We also observed different color pattern development in male and female adult fish (6-year-olds) around the reproductive period.     

Whole-body concentrations of cortisol and sex steroids in white sturgeon (Acipenser transmontanus, Richardson 1836) during early development and stress response

In general little is known about hormones and the ontogeny of the stress response in the early developmental stages of chondrostean fishes and in particular of white sturgeon (Acipenser transmontanus, Richardson 1836). In this study, we measured for the first time cortisol and sex steroids (testosterone and estradiol) in eggs, larvae, post-larvae, and fry of white sturgeon by radioimmunoassay (RIA), to elucidate some endocrine aspects of its development. The cortisol, testosterone, and 17β-estradiol of maternal origin found in unfertilized eggs of white sturgeon probably regulate both growth and development of the embryo. Cortisol decreased after fertilization, whereas testosterone and 17β-estradiol did not significantly change. During the late stages of embryo development and immediately after hatching, endogenous production of cortisol and sexual steroids, respectively, occurred. Sex steroids may be physiological inducers of gonad sex differentiation in sturgeon. All steroids showed an increase 10 days post-hatch (dph), near the transition from an endogenous to an exogenous energy source. Cortisol maintained the same basal levels even after metamorphosis, whereas testosterone and 17β-estradiol declined significantly in post-larvae at 35 and 45 days post-hatch. In addition, to evaluate the ontogeny of a functional hypothalamic-pituitary-interrenal (HPI) axis, larvae and fry were submitted to acute stress. The HPI axis did not seem to be functional on the first day post-hatch, but became so from the third day post-hatch onward.     

利用SSR分子标记检测鹅掌楸雄性繁殖适合度与性选择

本文利用SSR分子标记研究了鹅掌楸实验群体内个体的雄性繁殖适合度.结果表明:试验群体中,鹅掌楸雄性繁殖适合度在不同个体之间差异较为明显,变幅为0%～10.9%.鹅掌楸的性选择倾向在不同个体间差异较大,母本LS和BM性选择倾向明显,均倾向于种内交配,其种内交配比率分别为85.7%和94.1%,而母本HS和LYS性选择倾向不明显.鹅掌楸雄性繁殖适合度随交配距离的不同而变化,82%的有效花粉来自于35 m区域内的亲本,其累积雄性繁殖适合度为51.4%.交配距离、性选择倾向在鹅掌楸个体的雄性繁殖适合度中扮演重要角色.     

野牛草有性繁殖特性及其抗旱转录因子DREB的克隆

野牛草(Buchloe dactyloides(Nutt.)Eng elm.)是一种抗逆性强、管理粗放的暖季型草坪草。20世纪40年代,该草作为水土保持植物由美国引种到我国甘肃天水试种,表现出较好的适应性。目前,我国的野牛草品种较为单一,种子产量较低且不稳定,绝大部分种子依赖从国外进口,价格十分昂贵,国内多采用分株无性繁殖方法建植野牛草草坪,但费工费时、建坪效率低,大面积远距离应用十分困难,因此选育绿期长、种子产量高的野牛草新品种是野牛草研究的主要方向。     

中国明对虾(Fenneropenaeus chinensis)外部性征的分化及发育

中国明对虾(Fenneropenaeus chinensis)的性别分化和生殖器官发育是其繁殖生物学的重要部分,也是进行性别调控的基础.经过2年的取样观察,研究了中国明对虾雌性纳精囊和雄性交接器的分化与发育过程.结果显示,早在仔虾后16d (16 days post-larva,PL16)即开始雌雄分化,此时,雌虾第4与第5对步足间腹甲处的锥突出现明显下陷,而雄虾的没有下陷.PL54时,雌虾纳精囊瓣膜出现,然后继续发育,到PL124时形成纳精囊雏形;雄虾交接器发育较晚,到PL54时,雄虾第1泳足的内肢才出现分化,在PL106基本形成雄性交接器.     

稀土对杨树杂交种子数量和品质影响的初步研究

稀土元素从镧到镥(La—Lu,原子序数57—71)是元素周期表ⅢB族成员。它们在植物中的分布和作用国外很早就有研究,1878年Cossa就报道了(木菊)材、烟草、葡萄等植物中含有少量稀土。我国对稀土的研究起步较晚,农业方面的应用有十几年的历史,在小麦、水稻、苹果等主要作物上使用一般可增产8—10％、林业方面的应用只有几年的历史,稀土可以促进插条生根及苗木生长。但对于稀土在树木种子产量和品质方面的作用报道尚不多见,于是我们选择了适宜室内杂交的杨树为材料,利用稀土元素处理杨树切枝母本,对其杂交种子的数量和品质进行了初步研究。     

红麻新品种闽红298的选育

闽红２９８系１９８５年从红麻７２２×青皮三号有性杂交后代中选育而成的红麻新品种。１９８９—１９９７年与青皮三号复壮种进行省内外４６点次对比,平均亩产原麻４２３．３公斤,比青皮三号增产１６．１３％,达极显著。与粤７４—３原种对比４０点次,平均亩产原麻４２５．７公斤,比粤７４—３增产１２．７４％,也达极显著。该品种植株高大、茎粗、有效株数多、抗病力强、丰产稳定性好、适应性广。１９９５—１９９８年省内外累计生产示范６．９４２万亩。