Morphometry and mortality in pupae and adults of Brassolis astyra (Nymphalidae, Morphinae)

Abstract

The data presented are based on Brassolis astyra Godart, 1824 individuals sampled randomly in four locations of the State of Rio Grande do Sul, Brazil: Tupanciretã, São Martinho da Serra, Santa Maria - two places. Except in São Martinho da Serra, the data were obtained in urban areas, on Syagrus romanzoffianum palms (Palmaceae). The following parameters were investigated: egg laying number, hatching eggs index, number of miscarried eggs, eggs positioning on the host plant, sex ratio, parasitoid index, emergency pupa-adult frequency, longevity of pupae and adult stages, mass and volume of the pupae and morphometric measurements of pupae and adults' wings. Of eggs collected in Tupanciretã, 46% hatched, 43% had been parasitized and 11% were miscarried. On the other hand, in São Martinho da Serra only 4% of the eggs collected hatched, 95% had been parasitized and 1% were miscarried. In the other localities no eggs were found. Based on adults emerged from the pupae, it was verified that 77% of the males and females presented a normal morphology (viable) and 23% were malformed. The differences in the average values estimated for pupal longevity among the study sites, were statistically significant. The average frequency of adults was 0.47. The data obtained showed a sexual dimorphism in size (weigh) and form (volume) of the pupae. This suggests that the size and the form of the pupae can determine the adults' viability. Such effect could be associated with a stabilizing selection, where would be associated to optima values average of weigh and form. Although the origin of the sampled individuals varied, the parameters that determine the size and shape are in the same direction when comparing the two sexes. Data on longevity and mortality suggest that the estimated values can be influenced by the variability and ecology of the population from which the larvae were sampled.