The internal reproductive organs of females and males of Phytalus sanctipauli are described and illustrated. The amount of fat body in the abdominal cavity was assessed. The remaining in the soil, from March to September, of sexually immature females and males bearing the abdominal cavity totally filled with fat body characterized the state of diapause in this species, in Coxilha (52°20'W and 28°05'S), RS, Brazil.

The green aphid Schizaphis graminum (Rondani) is an important pest of Graminae. Samples of this aphid were collected at three environmentally distinct Brazilian localities, Passo Fundo (RS), Jaguariuna (SP) and Dourados (MS). Alatae and apterous viviparous forms were reared on the BR-35 wheat (Triticum aestivum) strain under controlled laboratory conditions and studied as to their variability in measures of body size and production of progeny. Univariate (ANOVA) and multivariate (canonical discriminant functions) techniques were used to evaluate differences among the three populations. Conspicuous differences between populations were observed in the length of five structures of the alatae and eight of the apterous forms, as well as in offspring production. The greatest dispersion in the length of general structures of the individuals obtained by the canonical discriminant function was for Passo Fundo, where climatic conditions are more severe and where aphids cause the most serious damage to wheat crop.

We examined the chromosome set of the aphid species Sitobion avenae, Schizaphis graminum and Methopolophium dirhodum by means of conventional staining and C, NOR, AluI and HaeIII banding methods. These species are considered important pests to several plants of economic interest in Brazil. No variation was observed in the number of chromosomes of S. avenae, whereas there was intraspecific variation in the other two species. Interspecific differences in the response to the banding treatments were observed. Whereas these techniques allowed the identification of several S. graminum chromosome pairs, only the AluI treatment was capable of inducing differential staining in the M. dirhodum chromosomes and no clear patterns emerged when the S. avenae preparations were treated
Por meio de coloração convencional e de métodos de bandamento C, NOR, AluI e HaeIII, foi feita uma tentativa de caracterizar o cariótipo e a variação no número cromossômico das espécies de afídeos Sitobion avenae, Schizaphis graminum e Methopolophium dirhodum, que são considerados como pragas importantes para várias plantas de interesse econômico no Brasil. Não foi encontrada variação no número cromossômico de S. avenae, enquanto que as outras duas espécies apresentaram variação numérica intra-específica. Diferenças interespecíficas quanto à resposta aos tratamentos de bandamento foram observadas. Através dos métodos utilizados, foi possível a identificação de vários pares cromossômicos de S. graminum, mas só o tratamento com AluI foi capaz de induzir coloração diferencial nos cromossomos de M. dirhodum, enquanto que nenhum padrão claro de bandamento apareceu nos preparados de S. avena

2EMBRAPA/CNPT, Caixa postal 569, 99001-970, Passo Fundo, RS.An. Soc. Entomol. Brasil 26(2): 223-228 (1997) Comparative Food Intake of Phytalus sanctipauli Blanch.(Coleoptera: Scarabaeidae) Larvae ABSTRACT -Food intake of 3rd instar larvae of Phytalus sanctipauli Blanch. was studied in the laboratory. Individually reared insects were given newly emerged seedlings of oat (Avena sativa), corn (Zea mays) or wheat (Triticum aestivum), or the three species together. The amount (dry mass) respectively of roots and seeds ingested was larger for wheat (28.5 and 41.5 mg), lower for oat (16.4 and 2.0 mg) and intermediate (22.6 and 24.9 mg) for corn. Leaf intake was similar for oat (18.2 mg) and wheat (19.8 mg) and larger for corn (2.1mg). Considering the seedling, consumption was larger for wheat either offered singly (89.8 mg) or not (56.9 mg). Grubs fed on wheat (100.2 mg) and corn (102.2 mg) were heavier than those fed on oat (85.9 mg). The average number of seedlings damaged/grub was larger for wheat (27.4) and oat (24.9) when compared to corn (0.9).KEY WORDS: Insecta, Melolonthinae, white grub, nutrition, food preference. RESUMO -O consumo alimentar de larvas de 3º estádio de Phytalus sanctipauliBlanch. foi estudado em laboratório. Os insetos foram criados individualmente e alimentados com aveia (Avena sativa), milho (Zea mays) ou trigo (Triticum aestivum) ou com as três espécies juntas. A quantidade (massa seca) ingerida de raiz e semente, respectivamente, foi maior em trigo (28,5 mg), menor em aveia (16,4 mg) e intermediária no milho (22,6 mg). O consumo de folha foi semelhante em aveia (18,2 mg) e trigo (19,8 mg) e significativamente superior ao de milho (2,1 mg). Avaliando-se a plântula como um todo, o consumo de trigo foi superior tanto quando as espécies vegetais foram oferecidas isoladamente (89,8 mg) quanto em conjunto (56,9 mg). O peso fresco médio das larvas ao término da alimentação foi maior em trigo (100,2 mg) e milho (102,2 mg) do que em aveia (85,9 mg). O número médio de plantas destruído por larva foi marcadamente maior em trigo e aveia (27,4 e 24,9, respectivamente) comparado com milho (0,9).PALAVRAS-CHAVE: Insecta, Melolonthinae, coró do trigo, alimentação, dano.