Abstract

DE SOUZA MENDONCA, JR., Milton. Plant diversity and galling arthropod diversity searching for taxonomic patterns in an animal-plant interaction in the Neotropics. Bol. Soc. Argent. Bot. [online]. 2007, vol.42, n.3-4, pp.347-357. ISSN 1851-2372.

Gall-inducers are a special guild of endophytic herbivores generating distinct structures known as galls. Gallers are species-specific, as the galls they induce: each gall morphotype is unique. The relationship between plants and gallers is close, and some of the hypotheses to explain galling diversity consider plants directly; others do not. Here I review current diversity hypotheses on galls and their hosts, adding ideas on the interpretation of galler host plant data. The example comes from an ongoing standardised inventory of galls and hosts in Rio Grande do Sul (RS) state, southern Brazil. The questions addressed here are whether: a) galls occur consistently on some plant taxa in different areas, b) these taxa are important for vegetation composition, and c) taxon size influences galling richness. Families harbouring more gallers are usually the same throughout the Neotropics (Fabaceae, Myrtaceae, and in RS, Asteraceae), which is not unexpected as these are important components of vegetation. Larger plant families have more galls, a pattern driven by Asteraceae. At lower taxonomic levels, the dominance of a few taxa in galler richness («super-hosts») is higher. Mikania and Eugenia , for example, hold much more galls than others in the RS survey.

Keywords : Gall; Species richness; Plant taxon size hypothesis; Fabaceae; Myrtaceae; Asteraceae.

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