Abstract: Morphological variation of eight aphid species feeding on the leaves of bamboos, viz. Astegopteryx bambusifoliae (Takahashi), Astegopteryx minuta (van der Goot), Cerataphis bambusifoliae Takahashi, Ceratovacuna silvestrii (Takahashi) and Chaitoregma tattakana (Takahashi) of Hormaphididae, Melanaphis bambusae (Fullaway) of Aphididae, and Takecallis arundinariae(Essig) and Takecallis taiwanus (Takahashi) of Drepanosiphidae, were studied based on morphometric data of 34 morphological characters, of which 28 characters were statistically analysed. The results indicated that some characters, such as body, siphunculi and antennae, were very different among the three families, but some others, such as the ultimate rostral segments, tarsal segmentsⅠ, tarsal segmentsⅡ and claws, were similar. The variations of the following characters within species were quite small: ultimate rostral segments (CV=3.73%-7.59%), tarsal segmentsⅠ(CV=4.16%-12.05%), tarsal segmentsⅡ (CV=3.10%-8.39%) and claws (CV=2.60%-11.68%). Principal component analysis filtered the first principal component, which included the characters of ultimate rostral segments, tarsal segmentsⅠ, tarsal segmentsⅡ and claws. The bivariate plots (ovals in plots were 95% confident elipses for every species) of these characters showed steady ranges. The results showed that the characters, such as ultimate rostral segments, tarsi and claws, which are related to aphid feeding behavior and adhesion on the surfaces of plants, were obviously similar among different taxa. These suggested that convergent adaptation occurred in these characters of the aphid species on the leaves' surfaces of bamboos. Combined with biological data of these aphids, the mechanism of morphological adaptation in these species was tentatively discussed.

Key words: Aphids, host plants, bamboos, morphological characters, morphological adaptation