Diversity, similarity and seasonal variation of the thysanopterofauna in Itapuã State Park, Viamão, RS, Brazil
Pinent SJM1,2, da C Pinent CE3, Romanowski HP1, Redaelli LR1,2, Cavalleri A1
1 Depto. Fitossanidade - UFRGS, Porto Alegre, RS.
2 Depto. Entomologia - EMBRAPA UVA E VINHO, Bento Gonçalves, RS
3 Dep. Estat¨ªstica - PUCRS, Porto Alegre, RS
Correspondence: silviapi@portoweb.com.br
The diversity, similarity and seasonal variation of the thysanopterofauna in different microhabitats were studied in the ¡°Parque Estadual de Itapu㡱 (30¡ã22¡¯S 51¡ã02¡¯W), RS, southern Brazil. Between June 1999 and May 2001, shoots (n = 1,274), flowers (n = 774), grass tussocks (n = 596) and leaf litter (n = 603) were sampled systematically in 20 points on four trails (T1- Pedreira beach, T2- Ara稢 beach, T3- Lagoinha, and T4- Grota hill). This resulted in 2,197 adult thrips determined in 73 species. The seasonal variation points to both N and S higher during summer and lower in winter. Estimated values for diversity were DMg = 9.357 and H¡¯ = 2.802. Dominance was low overall in the sample (1-D = 0.893). The highest abundance was obtained for flowers (N = 1,224). Although less abundant in individuals (N = 158), the leaf litter was rich in species. T2 had comparatively high numbers of thrips, resulting also in a high number of species (S = 43). The fauna showed very low similarities among microhabitats (MH lower than 0.2); among trails, similarity was higher: MH = 0.83 between T2 and T4. T1 had the most distinct fauna. We discuss the importance of sampling different types of vegetation and microhabitats so that specialised and generalist species can be recorded. (N = abundance; S = species richness; D = Simpson¡¯s index; 1 ¨C D = reciprocal Simpson index; DMg = Margaleff index; H¡¯ = Shannon-Wiener index; MH = Morisita-Horn¡¯s similarity index).
