Geographic and Temporal Variation in Natural Populations of Tetraopes tetraophthalmus

Abstract

Both geographic and temporal variation of 6 structural characters and 2 color characters are estimated for the cerambycid beetle Tetraopes tetraophthalmus. The precentage of the total variation contributed by differences among localities on the general level was greater for color characters than for structural. Color characters showed no differences among localities within limited areas and no differences from year to year in the same locality. Structural characters, in general, showed less marked interlocality differences over the insect''s whole range, but did vary from year to year and from place to place more locally. Discordance between structural and color characters is indicated both by comparison of these levels of variation and by the distributions of foci of high and low mean values of the characters over the insect''s range. Lesser amounts of discordance are apparent among structural characters and between the 2 color characters. There are reasons for expecting geographic character discordance to be a quite general phenomenon. The study of year-to-year variation over a 3-year period at 10 localities indicates that for the structural character "elytral length," peripheral localities are much more variable from year to year than are central localities. Some possible explanatory models are discussed.