Sexual Dimorphism And Female Individual Fecundity Of Six Species Of Gobioninae In The Jialing River,Southwest China

Gudgeons are a group of small and medium-sized fish that live in fresh water,and its morphology,ecology and reproduction are rich and diverse.In the choice of sexual and fecundity,faced with different survival pressure can lead to morphological characteristics between the sex,size,color and other differences.As the research objects,6 species of Gobioninae in Jialing River were used in this study.The biological evolution of the amphoteric and individual fecundity characteristics were analyzed under the existing phylogenetic framework.The relationship between morphological characteristics and phylogenetic relationships and the interrelations of morphological features were analyzed by systematic developmental methods?PCMs?and correlation analysis.The results of this study are as follows: 1,Sexual dimorphismA total of six species of Gudgeons in Jialing River were divided into three types.The results were as follows:1)Female was bigger than male: Hemibarbus labeo.Female individuals?body length,body mass?were significant larger than male,and in the head?head width?snout length and barbels length?,trunk?body width,trunk length,ventral fin length,anal fin coxal length,anal fin depth?features were also significantly increased of H.labeo.2)Male was bigger than female: Pseudorasbora parva,Abbottina rivularis.?1?P.parva: The males were significant larger than females.Some local morphological traits in males were increased significant than in the females,for example,the head traits?head length,snout length,oral width,postorbital head lenght?,the trunk traits?body depth,body width,length between dorsal fin and rhynchodaeum,pectoral fin length,length between pectoral fin and rhynchodaeum,dorsal fin coxal length,dorsal fin depth,ventral fin length,anal fin depth?and the tail traits?caudal peduncle depth,caudal peduncle width,caudal peduncle length?were significant larger in males than in females.?2?A.rivularis: The males were significant larger than the female individuals,and males were significantly increased in local features.Males in the head?head depth,snout length,barbels length?,trunk?Body depth,length between pectoral fin and ventral fin,pectoral fin length,dorsal fin depth,ventral fin length,anal fin depth,length between ventral fin and anal fin,length between anus and anal fin?and tail?caudal peduncle depth,caudal peduncle width,caudal peduncle length?characteristics were increased significant than in the females.3)Male and female individuals were similar: Squalidus argentatus,Rhinogobio typus and Saurogobio dabryi.?1?There was no significant difference between male and female of S.argentatus in body size,but the head width and the length and diameter of eyes were significant smaller than that of males.Females were significantly larger than that of male in the body height,body width,trunk distance and thoracic circumference,but the length of dorsal fins,the length of anal fins and the length of anal fin were significantly smaller than that of male.?2?There was no significant difference between male and female of R.typus,but the females' head?head length,head width,snout length?,trunk?body depth,length between pectoral fin and ventral fin,pectoral fin length,dorsal fin depth,ventral fin length,anal fin depth,length between anus and anal fin,length between ventral fin and anal fin?characteristics were smaller than males,the result was opposite in the caudal peduncle width.?3?No significant difference in the body size between-sex of S.dabryi.However,some local morphological traits?such as cephalosome and the truck?exhibited significant difference between males and females,for example,the head,the pectoral fin and the pelvic fin were significantly larger in males than in females,while the width,height and length of trunk exhibited opposite results.2,Individual fecundity:We investigated the individual fecundity of six species of gudgeons in the Jialing River,and compared with the historical data.We found that there were two main kinds of changes.The results were as follows:1)Less than historical data: H.labeo and R.typus.?1?H.labeo: Individual absolute fecundity?F?were 11 667 31 396 eggs,with an average of 20 365 eggs.Individual relative fecundities in body length were 60.14 155.33 eggs·mm^-1,with an average of 92.97 eggs·mm^-1.Individual relative fecundities in body mass were in the range of 63.26 199.75 eggs·g^-1,an average of 100.577 eggs·g^-1.?2?R.typus: Individual absolute fecundity?F?were 2 012 26 865 eggs,with an average of 9 214 eggs.Individual relative fecundities in body length were 10.21¹24.95 eggs·mm^-1,with an average of 42.11 eggs·mm^-1.Individual relative fecundities in body mass was in the range of 22.33²36.70 eggs·g^-1,an average of 80.61 eggs·g^-1.2)More than historical data: S.argentatus,A.rivularis,P.parva,S.dabryi.?1?S.argentatus: Individual absolute fecundity?F?were 2 265²1 320 eggs,with an average of 9 658 eggs.Individual relative fecundities in body length were 26.65¹91.7 eggs·mm^-1,with an average of 87.53 eggs·mm^-1.Individual relative fecundities in body mass was in the range of 155.80 689.98 eggs·g^-1,an average of 347.50 eggs·g^-1.?2?A.rivularis: Individual absolute fecundity?F?was 1 068⁹ 692 eggs,with an average of 5 467 eggs.Individual relative fecundities in body length were 18.73¹25.87eggs·mm^-1,with an average of 73.10 eggs·mm^-1.Individual relative fecundities in body mass were in the range of 296.59¹ 409.92 eggs ·g^-1,an average of 658.24 eggs·g^-1.?3?P.parva: Individual absolute fecundity?F?were 542² 464 eggs,with an average of 1 573 eggs.Individual relative fecundities in body length were 11.32⁴5.16 eggs·mm^-1,with an average of 27.92 eggs·mm^-1.Individual relative fecundities in body mass was in the range of 230.45⁷24.83 eggs·g^-1,an average of 414.74 eggs·g^-1.?4?S.dabry: Individual absolute fecundity?F?were 979¹9 979 eggs,with an average of 10 418 eggs.Individual relative fecundities in body length were 11.7¹65.1 eggs·mm^-1,with an average of 87.8 eggs·mm^-1.Individual relative fecundities in body mass were in the range of 137.9¹250.6 eggs·g^-1,an average of 702.6 eggs·g^-1.3,EvolutionBased on the phylogenetic relationship,the evolutions of the amphoteric and fecundity characteristics of 6 species of gudgeons in Jialing River were analyzed.The results were as follows:1)The ancestral trait reconstruction results showed that:?1?the body was evolved from a cylindrical to lateral flat.?2?The type of sexual dimorphism was evolved from the third type of male and female similar to the two types of females' lager than males and the males larger than females.?3?The ancestral traits of the type of spawning and the frequency to spawning were not clearly and need the outer group to identify.?4?Nest protection behavior: the evolution from non nest protection behavior to have.?5?Second sexual characteristics: the evolution from have secondary sexual character to not have.2)The two characters of the type of spawning and the frequency to spawning were significant constraints in the evolution of phylogenetic.3)The characteristics of sexual dimorphism were positively correlated with the nest defence behavior,and thereexisted negative correlate between the characteristics of sexual dimorphism and absolute fecundity were in evolution.And the vast characteristics were reached significant correlation among evolution.By studying the sexual dimorphism and individual fecundity and their evolution patterns of the Gobioninae in the Jialing River,there were of great theoretical values to understand the biological significances and differentiation diversities of six species Gudgeons in Jialing River which represent the East Asian endemic Cyprinid group.At the same time,the results could help to explain Gobioninae's selection strategies between male and female individuals when facing pressure and to promote the proliferation and protection of their resources and the artificial breeding and breeding of the Gobioninae.