Bite force is an important performance indicator of individual fitness that is closely related to food acquisition,male competition,and mating selection.It is also affected by a variety of factors and different mechan...Bite force is an important performance indicator of individual fitness that is closely related to food acquisition,male competition,and mating selection.It is also affected by a variety of factors and different mechanisms.Therefore,it is relatively difficult to understand the evolutionary driving forces of changes in bite force.In this study,the driving factors affecting the bite force of wild-derived red junglefowl(Gallus gallus jabouillei)were investigated from the aspects of morphological indicators and physiological characteristics.Results showed that the bite force of wild-derived red junglefowl was directly related to sex,showing obvious sexual differences.However,there was no correlation between the plasma testosterone level and bite force.The bite force of males was significantly greater than that of females,and the body index(i.e.,PC1 of five body measures,namely body mass,body length,wing length,tail length,and tarsus length),the grasp index(i.e.,tomial length×bill width)of males were significantly greater than those of females.Sexual selection may have played a key role in the evolution of bite force in the red junglefowl.Future studies should examine other key factors affecting changes in bite force to verify the correlation between secondary sexual characteristics and bite force in red junglefowls.展开更多
The Douala-Buea Region(DBR;4°-5°N,9°-10°30’E),a portion of the southern Cameroon passive margin,developed on the Proterozoic granito-gneissic basement and the Cretaceous to Recent volcanosedimenta...The Douala-Buea Region(DBR;4°-5°N,9°-10°30’E),a portion of the southern Cameroon passive margin,developed on the Proterozoic granito-gneissic basement and the Cretaceous to Recent volcanosedimentary cover,was explored in order to evaluate the lithology and tectonics controls on its landscape usingthequalitativeandquantitative geomorphological analyses based on 30 m resolution Digital Elevation Models(DEM)and field evidences.This area displays an uneven and complex landscape differentiated into four morphological units:Douala,Nkondjock,Kumba and Buea Units.The Douala Unit corresponds to the Coastal Plain and is extended on the Douala-Kribi/Camposedimentarybasin.The Nkondjock Unit represents a middle plateau developed on a Proterozoic granito-gneissic basement.The Kumba Unit matches with the southernmost volcanic Western Cameroon High Plateau.The Buea Unit corresponds to the Mount Cameroon stratovolcano.The relief analysis through mountain-front sinuosity(Smf,1.19–1.43)and relative relief ratio(Rr,0.10–2.31)vary from one unit to another.The drainage network analysis including drainage patterns,stepped longitudinalriverprofiles,theassociated morphometric indexes,notably the concavity index(IC,0.56–0.88),deviation(D,267–2912 m),basin asymmetry factor(A_(F),6.37–42.12),hypsometric integral(HI,0.10–0.29),valley floor width to valley height ratio(V_(f),0.36–2.75),elongation ratio(R_(e),0.30–0.50),watershed slope(S,6.88–88.88)and stream length gradient index(SL,0–3332)vary from one basin to another too.These results also show the heterogeneous and uneven DBR landscape controlled by its lithology and active tectonics.The drainage system reveals concave to concavo-convex longitudinal river profile shapes with knick points,asymmetric basins,and fault reactivations,and highlights the tectonics activity that used to occur through the time and their control on the morphology.Together,they document the lithostructural controls on the DBR landscape evolution,extendable in the whole SW Cameroon margin.展开更多
基金supported by the National Natural Science Foundation of China(no.31800320 and no.32360250 to XR)Natural Science Foundation of Hainan Province(no.320RC506 to XR)+3 种基金funded by the project supported by the Scientific Research start-up Fund of Hainan University[no.KYQD(ZR)20057]the Teaching Research of Hainan University(no.Hdsz20-9)supported by Hainan Tropical Rainforest Conservation Research Project,ZDYF2023RDYL01(supported by the Hainan Institute of National Park,HINP,KY-24ZK02)supported by the specific research fund of The Innovation Platform for Academicians of Hainan Province.
文摘Bite force is an important performance indicator of individual fitness that is closely related to food acquisition,male competition,and mating selection.It is also affected by a variety of factors and different mechanisms.Therefore,it is relatively difficult to understand the evolutionary driving forces of changes in bite force.In this study,the driving factors affecting the bite force of wild-derived red junglefowl(Gallus gallus jabouillei)were investigated from the aspects of morphological indicators and physiological characteristics.Results showed that the bite force of wild-derived red junglefowl was directly related to sex,showing obvious sexual differences.However,there was no correlation between the plasma testosterone level and bite force.The bite force of males was significantly greater than that of females,and the body index(i.e.,PC1 of five body measures,namely body mass,body length,wing length,tail length,and tarsus length),the grasp index(i.e.,tomial length×bill width)of males were significantly greater than those of females.Sexual selection may have played a key role in the evolution of bite force in the red junglefowl.Future studies should examine other key factors affecting changes in bite force to verify the correlation between secondary sexual characteristics and bite force in red junglefowls.
文摘The Douala-Buea Region(DBR;4°-5°N,9°-10°30’E),a portion of the southern Cameroon passive margin,developed on the Proterozoic granito-gneissic basement and the Cretaceous to Recent volcanosedimentary cover,was explored in order to evaluate the lithology and tectonics controls on its landscape usingthequalitativeandquantitative geomorphological analyses based on 30 m resolution Digital Elevation Models(DEM)and field evidences.This area displays an uneven and complex landscape differentiated into four morphological units:Douala,Nkondjock,Kumba and Buea Units.The Douala Unit corresponds to the Coastal Plain and is extended on the Douala-Kribi/Camposedimentarybasin.The Nkondjock Unit represents a middle plateau developed on a Proterozoic granito-gneissic basement.The Kumba Unit matches with the southernmost volcanic Western Cameroon High Plateau.The Buea Unit corresponds to the Mount Cameroon stratovolcano.The relief analysis through mountain-front sinuosity(Smf,1.19–1.43)and relative relief ratio(Rr,0.10–2.31)vary from one unit to another.The drainage network analysis including drainage patterns,stepped longitudinalriverprofiles,theassociated morphometric indexes,notably the concavity index(IC,0.56–0.88),deviation(D,267–2912 m),basin asymmetry factor(A_(F),6.37–42.12),hypsometric integral(HI,0.10–0.29),valley floor width to valley height ratio(V_(f),0.36–2.75),elongation ratio(R_(e),0.30–0.50),watershed slope(S,6.88–88.88)and stream length gradient index(SL,0–3332)vary from one basin to another too.These results also show the heterogeneous and uneven DBR landscape controlled by its lithology and active tectonics.The drainage system reveals concave to concavo-convex longitudinal river profile shapes with knick points,asymmetric basins,and fault reactivations,and highlights the tectonics activity that used to occur through the time and their control on the morphology.Together,they document the lithostructural controls on the DBR landscape evolution,extendable in the whole SW Cameroon margin.
