Vrsansky, （2000） considered there is decreasing variability in the forewings of cockroaches through time, based on a study of fossil and Recent species. This study tests his theory, based on a study of four Recent s...Vrsansky, （2000） considered there is decreasing variability in the forewings of cockroaches through time, based on a study of fossil and Recent species. This study tests his theory, based on a study of four Recent species of cockroaches： Blattella germanica （Blattellidae）, Polyphaga aegyptiaca （Polyphagidae）, Shelfordella lateralis （Blattidae） and Blaberus craniifer （Blaberidae）. The new results, based on the coefficient of variation （CV） of the number of veins, indicate that Recent species can be more variable than fossil species and therefore do not support the theory. The results also show that at least 30 complete wings of the same species are required for a reliable CV value that is compa- rable between species.展开更多
文摘Vrsansky, （2000） considered there is decreasing variability in the forewings of cockroaches through time, based on a study of fossil and Recent species. This study tests his theory, based on a study of four Recent species of cockroaches： Blattella germanica （Blattellidae）, Polyphaga aegyptiaca （Polyphagidae）, Shelfordella lateralis （Blattidae） and Blaberus craniifer （Blaberidae）. The new results, based on the coefficient of variation （CV） of the number of veins, indicate that Recent species can be more variable than fossil species and therefore do not support the theory. The results also show that at least 30 complete wings of the same species are required for a reliable CV value that is compa- rable between species.
