Anti-Fertility Effects and Mechanism of the Plant Extract Shikonin on Mice

Controlling fertility of rodent pests has become an effective means of controlling the population of grassland rodents in China. Recently, research has focused on how to select environmentally-friendly sterilants without pollution effects, and to realize sustainable control of pest rodent populations. Sterilants from plant extracts have been mainly selected. In this study, mice were used as the experimental subjects for research on the anti-fertility effects of plant extracts of shikonin and the anti-fertility mechanism of shikonin extract was determined. The mice were divided into four groups, including one control group and three experimental groups. There were three applications of shikonin extract in different concentrations (5 mg·kg-1, 20 mg·kg-1 and 50 mg·kg-1). The mice gavage experiments indicated that a shikonin concentration of 50 mg·kg-1 had the expected anti-fertility effects. Mice copulation experiments showed that the 50 mg·kg-1 shikonin treatment had significant anti-fertility effects on both female-treatment and female-male-treatment groups. The results of the PCR analysis on the AgRP and ghrelin mRNA from female ovaries and male testicles indicated that shikonin could control mice reproduction by regulating the pituitary gonadal axis. Shikonin, as plant source sterile agent, would have more ideal effects for functioned both sexes sterility.

Study on the Classification and Diversity of Zonal Rodent Community in Semi-Desert and Desert Areas of China

Many studies focus on rodent community pattern and changing at present in the world, but most of them are conducted in small plots. Few studies investigated the rodent community classification and diversity in semi-desert and desert areas at regional scale, although some researchers started to study the change of animal community patterns on a large scale. We investigated rodent communities in desert, non-irrigated farming land and desert steppe of Inner Mongolia, covering an area of 380,000 km2 from May to August in 1988-1993 and in 1998-2003, respectively, in order to reveal the changing characteristics of zonal rodent communities. The community classification and diversity of rodents were analyzed in research areas. The results suggested that the communities could be classified in 9 zonal types. Spermophilus dauricus, Cricetulus longicaudatus and Eutamias sibiricus were dominant species in Community I;Phodopus roborovskii, Cricetulus barabansis and Cricetulus longicaudatus were dominant in Community II;Meriones unguiculatus, Phodopus roborovskii and Cricetulus longicaudatus were dominant in Community III;Allactaga sibirica, Allactaga bullata and Spermophilus dauricus were dominant in Community IV;Allactaga bullata, Dipus sagitta and Meriones unguiculatus were dominant in Community V;Meriones meridianus, Spermophilus dauricus and Allactaga bullata were dominant in Community VI;Allactaga sibirica, Allactaga bullata and Dipus sagitta were dominant in Community VII;Phodopus roborovskii, Dipus sagitta and Allactaga sibirica were dominant in Community VIII;Meriones meridianus, Dipus sagitta and Allactaga sibirica were dominant in Community IX. The community diversity and evenness analysis showed that the edge effect of community, the effect of disturbance and habitat fragmentation and scale effect were significantly correlated with community diversity in the semi-desert and desert regions. The ordinal results of 9 zonal rodent communities were in accordance with the results analyzed with similar community indices, showing the habitat change in the characteristics of the above-mentioned groups.

我国草原病虫鼠害现状、研究进展与治理对策

中国草地面积2.65亿公顷,具有范围广、类型多的特点,是我国重要的陆地生态系统,也是我国畜牧业可持续发展的主要载体。长期以来,草原病害、虫害、鼠害频发,一直是威胁我国草原生态安全、畜牧业生产和人民身体健康的重要生物灾害。近年来,国家对草原生态保护与修复工作给予了大力支持和投入,草原病虫鼠害治理取得了显著进展。但是,在当前气候变化与人类活动不断加剧的影响下,草地病害、虫害、鼠害的发生和防控面临新的困难和挑战。由于草地病虫鼠害种类多、分布范围广、治理难度大,整体防控形势依然严峻,在未来仍需加大研究和治理力度。本文简要总结了我国草原病虫鼠害现状及研究进展,梳理和凝练了当前治理中存在的关键科学问题,并提出了相应的治理对策与建议。

Effects of levonorgestrel-quinestrol(EP-1)treatment on Mongolian gerbil wild populations:a case study

Rodent pest population outbreaks occur frequently in grassland ecosystems in northern China.The Mongolian gerbil(Meriones unguiculatus)is a dominant pest rodent which is distributed across the semi-desert grasslands of Inner Mongolia,China.In 2009,we studied the contraceptive effect of levonorgestrel-quinestrol(EP-1),concentration 50 ppm,on a wild Mongolian gerbil population.The one-off contraceptive treatment was compared with a control group using a semi-monthly live trapping method in the Ordos Semi-desert Grassland Region of Inner Mongolia.The results show that juveniles were not recruited in spring in the treatment group.Ratios of juveniles in the control and treatment groups showed significant semi-monthly differences from spring to summer(one-way ANOVA,F_(2,14)=7.53,P<0.05).Between both groups,annual fluctuations of juvenile and total population densities were significantly different respectively(F_(2,14)=4.64,P<0.05;F_(2,18)=7.72,P<0.05).The contraceptive EP-1 delayed the normal reproductive pattern of Mongolian gerbil populations.This suppressed birth rates of gerbil populations,reduced their densities,and changed their age structures.The period of EP-1 baiting should be extended but it could be an ideal method for controlling Mongolian gerbil populations during each breeding season.

Fluctuations and patterns of desert rodent communities under human disturbance:fluctuating tendency and sensitive response of their population

The four kinds of sites under different kinds of human disturbances,i.e.a farmland area,a rotational-grazing area,an over-grazing area and a prohibited-grazing area,were selected in the typical region of the Alashan Desert of Inner Mongolia from April to October in 2002,2003 and 2004 respectively.The fluctuating tendency of rodent communities and the sensitive response of their populations were studied using mark-recapture and trap-day methods.The four kinds of mark-recapture samples and line samples were taken in different human disturbance areas.The area of the mark-recapturing sample was 0.95 hm2 and that of the line sample was 10 km2.The samples were collected every month in the mark-recapturing sites for four consecutive days and in line sites in April,July and October every year.The variable matrix was composed of the numbers of captured rodents of the rodent communities.The sensitive response of the populations in the communities was analyzed with principal component analysis(PCA).Results showed that there were different types of rodent communities under different kinds of human disturbance on two scales in three years.In each scale,there were large differences in both the number of species and the number of main population in the rodent communities under different kinds of human disturbance on the farmland area and over-grazing area especially.The results of PCA showed that the sensitive response of the populations of the communities was significantly different under different kinds of human disturbance on the two scales in the three years.Cricetulus barabensis was the most sensitive on the farmland area,there were no differences in sensitive response of the various rodents on the rotational-grazing area,and Dipus sagitta and Phodopus roborovskii were the most sensitive in the over-grazing area.