Commercial farming of anuran species that are declining in the wild raises a need to discriminate wild from farmed frogs.We hypothesized wild frogs might have extended hindlimbs due to greater frequency or intensity o...Commercial farming of anuran species that are declining in the wild raises a need to discriminate wild from farmed frogs.We hypothesized wild frogs might have extended hindlimbs due to greater frequency or intensity of jumping relative to farmed frogs,highlighting a morphometric approach to discrimination of wild from farmed frogs using hindlimb length.In the present study,Dybowski＇s frog（Rana dybowskii） was used to test this hypothesis.We measured body mass（Mb） and hindlimb length（Lh） of 2-year old farmed frogs and wild frogs aged 2 to 5 years.Dybowski＇s frog demonstrated significant dimorphism in Mb and Lh.Mb was significantly greater among farmed 2-year old frogs in both sexes（p=0.000）,while only among females was Lh significantly greater for wild frogs（p=0.000）.Lh/Mb was used as an index for origin discrimination to eliminate the influence of Mb due to variation of husbandry conditions among farms.Mean Lh/Mb for farmed frogs was significantly lower than for wild frogs（p=0.000） in the 2-year old age class.Discrimination correctly classified 84.4% of farmed and 96.3% of wild male frogs.Among females,92.9% of farmed frogs and 90.1% wild frogs were correctly classified.The overall correctness of classification was 92.1% and 90.8% for males and females,respectively.However,Lh/Mb revealed variation with age,resulting in reduced discriminative power for frogs ≥3 years old.We introduced a coefficient Ce to adjust the Lh/Mb of frogs ≥3 years to the level equivalent to 2-year frogs.The adjustment achieved 89.5% for overall correctness of origin for wild males and 92.4% for wild females ≥3 years old.These results show that Lh/Mb is an effective index to discriminate wild from farmed Dybowski＇s frog.Since the physical demands of jumping are common among anurans,this index is also potentially applicable to other anuran species.展开更多
Visual responses of 125 units have been extracellularly recorded with glass micropipettesfrom the left nucleus isthmi in the frog Rana nigromaculata, and 101 electrode tip positionsmarked with cobalt staining to recon...Visual responses of 125 units have been extracellularly recorded with glass micropipettesfrom the left nucleus isthmi in the frog Rana nigromaculata, and 101 electrode tip positionsmarked with cobalt staining to reconstruct a visual field map in the nucleus. 80% of the unitsrecorded show ON-OFF responses to a stationary spot of light and many are directionally selec-tive in response to black or white targets moving through their receptive fields. All the cobalt-marked ssots are within the nucleus, indicating that the nucleus isthmus proper is a restrictedpart of the frog visual system. There is a visual field map in the nucleus. The entire contra-lateral hemifield and the nasal 40°of the ipsilateral hemifield project on the nucleus topog-raphically. A cell-free band inside the nucleus is a boundary line separating the contralat-eral hemifield from the ipsilateral one. Dorsal to it is the contralateral field representation.The upper visual field projects on the rostral half of the nucleus and the central and medio-ventral portion of its caudal half. The lower field is represented on the dorsal and lateralpart of the caudal half. Fifteen binocular units have been found from the nucleus, 13 ofwhich arc dominantly activated by the contralateral eye, the other two are almost equallyexcited by either eye. These binocular units are mainly situated in the medulla of the rostralhalf of the nucleus isthmus.展开更多
基金supported by the Project of Tackling Key Problems of Science and Technology of Heilongjiang Province, China (GB06B205-3)Program of Wildlife Conservation and Breeding of State Forestry Administration of China (2008)Special Fund for Postgraduate Dissertation of Northeast Forestry University (2009)
文摘Commercial farming of anuran species that are declining in the wild raises a need to discriminate wild from farmed frogs.We hypothesized wild frogs might have extended hindlimbs due to greater frequency or intensity of jumping relative to farmed frogs,highlighting a morphometric approach to discrimination of wild from farmed frogs using hindlimb length.In the present study,Dybowski＇s frog（Rana dybowskii） was used to test this hypothesis.We measured body mass（Mb） and hindlimb length（Lh） of 2-year old farmed frogs and wild frogs aged 2 to 5 years.Dybowski＇s frog demonstrated significant dimorphism in Mb and Lh.Mb was significantly greater among farmed 2-year old frogs in both sexes（p=0.000）,while only among females was Lh significantly greater for wild frogs（p=0.000）.Lh/Mb was used as an index for origin discrimination to eliminate the influence of Mb due to variation of husbandry conditions among farms.Mean Lh/Mb for farmed frogs was significantly lower than for wild frogs（p=0.000） in the 2-year old age class.Discrimination correctly classified 84.4% of farmed and 96.3% of wild male frogs.Among females,92.9% of farmed frogs and 90.1% wild frogs were correctly classified.The overall correctness of classification was 92.1% and 90.8% for males and females,respectively.However,Lh/Mb revealed variation with age,resulting in reduced discriminative power for frogs ≥3 years old.We introduced a coefficient Ce to adjust the Lh/Mb of frogs ≥3 years to the level equivalent to 2-year frogs.The adjustment achieved 89.5% for overall correctness of origin for wild males and 92.4% for wild females ≥3 years old.These results show that Lh/Mb is an effective index to discriminate wild from farmed Dybowski＇s frog.Since the physical demands of jumping are common among anurans,this index is also potentially applicable to other anuran species.
文摘Visual responses of 125 units have been extracellularly recorded with glass micropipettesfrom the left nucleus isthmi in the frog Rana nigromaculata, and 101 electrode tip positionsmarked with cobalt staining to reconstruct a visual field map in the nucleus. 80% of the unitsrecorded show ON-OFF responses to a stationary spot of light and many are directionally selec-tive in response to black or white targets moving through their receptive fields. All the cobalt-marked ssots are within the nucleus, indicating that the nucleus isthmus proper is a restrictedpart of the frog visual system. There is a visual field map in the nucleus. The entire contra-lateral hemifield and the nasal 40°of the ipsilateral hemifield project on the nucleus topog-raphically. A cell-free band inside the nucleus is a boundary line separating the contralat-eral hemifield from the ipsilateral one. Dorsal to it is the contralateral field representation.The upper visual field projects on the rostral half of the nucleus and the central and medio-ventral portion of its caudal half. The lower field is represented on the dorsal and lateralpart of the caudal half. Fifteen binocular units have been found from the nucleus, 13 ofwhich arc dominantly activated by the contralateral eye, the other two are almost equallyexcited by either eye. These binocular units are mainly situated in the medulla of the rostralhalf of the nucleus isthmus.
