Intraspecific variation within Orosius argentatus Evans (Hemiptera: Cicadellidae): colour polymorphisms, morphometric analyses and host associations

Abstract

Orosius argentatus shows extreme colour variation and is reputedly highly polyphagous, circumstances that both warrant confirmation that the taxon comprises only one species. Because the species transmits phytoplasma pathogens between plants, information on species status is relevant to epidemiological studies. Replicated field samples, taken in Mareeba, North Queensland, over 2 years indicated that O. argentatus is the most abundant leaf-hopper in stylo (Stylosanthes scabra) and is relatively hostspecific on cultivated stylo, at least locally. A priori groupings of colour types were established for morphometric analyses of head, prothorax, tibia, wing and genitalia characters. No consistent morphological differences were detected across the colour types, and results from colour heritability trials, although limited, revealed that females could produce progeny that belong to multiple colour types. The results from this study suggest individuals that key out to the species O. argentatus, despite being polymorphic in colour, cannot be clearly separated on any morphological basis and therefore are likely to belong to a single, interbreeding population. The colour variation in adults is therefore a polymorphism.

Comparison of Traditional and Next-Generation Approaches for Uncovering Phytoplasma Diversity, with Discovery of New Groups, Subgroups and Potential Vectors

“…P. stylosanthis’ was recently described [ 43 ] and restricted to Australia where it is associated with diseases on Stylosanthes scabra , an economically important plant used for improvement of native pastures [ 56 ], Carica papaya and Solanum tuberosum . The association with Orosius argentatus was expected because stylo is a known host plant [ 57 ] and this leafhopper is also a known vector of phytoplasmas in group 16srII which are found in mixed infections on the same host plants [ 58 ].…”