Iannuzzi, Roberto , Adami-Rodrigues, Karen , Damiani Pinto, Iraja .
Permian plant-insect interactions in a Gondwana flora of southern Brazil.
Leaf compressions and impressions from Gondwanan floras of Permian age in the state of Rio Grande do Sul, Brazil, provide evidence for several types of external interactions by insects. The material analyzed originates from the Rio Bonito (Artinskian to Kungurian) and Irati/Serra Alta (Kungurian-early Kazanian) Formations and was collected from horizons interpreted as representing wet palaeoenvironments: marginal accumulations of ancient peat or deposits that formed close to the shoreline. The principal groups of phytophagous insects inferred as the herbivore culprits are orthopteran-like, homopterous Hemiptera and holometabolous Coleoptera. A qualitative analysis of plant-insect interactions from these deposits indicates eleven categories of damage inflicted on the vascular plants: continuous and discontinuous external foliage feeding activity of the foliar edge and apex, removal of the foliar lamina, mining, skeletonization, small incisions related to piercing-and-sucking, oviposition scars, and galling. Among the damages related to herbivory, the first five types mentioned above were detected in 8,24% of the specimens (total = 352). A quantitative analysis allowed us to determine the proportion of herbivorized area removed (0.47% ) and the herbivory index (0.48%) which, in spite of its low value, give us a relative idea, per taxa, of the incidence of herbivorization of the floral assemblages studied. The present study concludes that possibly these phytophagous insects had a preference for Glossopteris and less of a specific preference for Cordaites and Gangamopteris foliage.
1 - Universidade Federal do Rio Grande do Sul, Departamento de Paleontologia e Estratigrafia, Instituto de Geociencias, Av. Bento Goncalves 9500, Porto Alegre, RS, 91.509-900, BRAZIL
Presentation Type: Poster
Location: Special Event Center (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 12:30 PM