Systematics of Pistacia: Insights from specialist parasitic aphids

Clarifying the systematics of the genus Pistacia (Anacardiaceae) has been a challenging task. The use of several classical and modern classification tools resulted in disagreements. Pistacia spp. are the obligate hosts of highly specialized gall-forming aphids (Homoptera: Fordinae). It is well known that closely related species of insects may utilize closely related plants. A complete linkage cluster analysis of Pistacia species, based on presence/absence of thirteen aphid genera, is presented. Aphids recognized between evergreen and New World Pistacia species. Other Pistacia species are clustered into two groups: "Vera" (P. vera, P. atlantica, P. mutica) and "Khinjuk" (P. khinjuk, P. chinensis, P. integerrima, P. palaestina, P. terebinthus). Fordinae contribution to Pistacia taxonomy at the species and hybrid levels is discussed. The close association between insect herbivores and their hosts deserves to be used more often by plant taxonomists.