Pupal Melanization in Heliconius erato phyllis (Lepidoptera; Nymphalidae): Genetic and Environmental Effects

Abstract

This paper deals with estimates of heritability and the effect of two different kinds of environment on the melanization of pupae in the butterfly Heliconius erato phyllis. The results for heritability showed greater differences when the offspring were regressed on male or female values for pupal colour. Pupal colour followed a system of discrete scores, from 2 for the light pupae to 5 for the darkest one. Estimate of the heritability (h2) was 0.44 when the average score of the siblings were regressed on the mid-parental value. When regressed on the male parent, h2 was larger (0.54), being very low when regressed on the female parent (0.09). Estimate by the analysis of variance was also 0.44 when both male and female sibs were included in the analysis (for male sibs, h2=0.43 and for female sibs, 0.47). To test for the effect of the environment, each brood was divided in three, one being the control, the second subjected to a black environment when reaching the fifth instar and the third to a white environment. Those in the black environment originated dark pupae that scored 5 or 4; for those in the white environment, there was no difference with the controls. Caterpillars when entering the prepupal stage were also subjected to the black treatment (early and late prepupal stage, respectively, for treatments called black A and black B). A significant effect was observed only when early prepupal stage was subjected to the black environment.

On the reliability of a simple method for scoring phenotypes to estimate heritability: A case study with pupal color in Heliconius erato phyllis , Fabricius 1775 (Lepidoptera, Nymphalidae)

“…The estimates were virtually the same as those reported by Ferreira et al (2006). These findings indicate that, regardless of the method used to estimate heritability (regression or analysis of variance), the h 2 value was low (not significantly different from zero, except for two values indicated in Table 1).…”

“…A further complication is that pupal color in this species is strongly influenced by the environment (Ferreira et al , 2006). There are at least two explanations for these results.…”

“…The procedures applied to the qualitative method were also used with the quantitative method (for details, see Ferreira et al , 2006). The sample sizes used here were slightly different from our previous report since we tried to use an equal number of exuviae in both methods.…”

“…We recently described pupal melanization in Heliconius erato phyllis , Fabricius 1775 (Nymphalidae, Heliconiinae) and the role played by genetic and environmental factors in the expression of this phenotype (Ferreira et al , 2006). Twenty-eight inbred and non-inbred broods were subjected to different treatments designed to distinguish between genetic and environmental influences.…”

Courtship behavior of Heliconius erato phyllis (Lepidoptera, Nymphalidae) towards virgin and mated females: conflict between attraction and repulsion signals?

“…study model of evolutionary biology, with most recent attention on reproductive isolation and speciation mechanisms (McMillan et al 1997;Jiggins et al 2001;Jiggins et al 2004;Mavárez et al 2006). In the state of Rio Grande do Sul (Brazil), one of the most studied species is H. erato phyllis, mainly concerning genetic and ecological aspects (Périco and Araújo 1991;Silva and Araújo 1994;Moreira 2002, 2004;Kerpel and Moreira 2005;Ferreira et al 2006). This species has two mating strategies.…”