Previous observations of Heliconius erato phyllis females being intensively courted a few days after mating contradict the proposal of sexual repulsion caused by a male-transferred antiaphrodisiac. Furthermore, data on courtship in Heliconius butterflies are almost absent from the literature. In this work we aim to describe the courtship behavior of H. erato phyllis and to compare it towards virgin and mated females. Sexual interactions using both kinds of females were observed and filmed in seminatural conditions for subsequent analysis and quantification. Courtship of virgin and mated females differed qualitatively and quantitatively, but the results do not agree with the proposal of sexual repulsion. The differences found indicate that the courtship sequence towards mated females is interrupted in the transition that would lead to the behavior immediately prior to copulation, in such a way that the male continues courting the female in an intermediate phase. Preliminary tests even showed that older females, virgin or not, are much less courted by males. We suggest that there is a trade-off between an attraction pheromone, important for males to locate female pupae, and the male-transferred antiaphrodisiac, so that young, mated females may have both signals active.
For many spiders, sex pheromones associated with female silk are important stimuli that elicit male searching and courtship behaviors. In that context, female sexual receptivity and chemical attractiveness can depend on age and reproductive status. In Paratrechalea ornata (Mello-Leitao 1943) (Araneae: Trechaleidae), males offer females a nuptial gift (a prey wrapped in silk) during courtship. Gift construction is elicited by the presence of female silk, and silk attractiveness is influenced by female age, increasing from 20 days after the female reaches adulthood. Our goal was to investigate whether female age affects female sexual receptivity and to discuss the relationship between receptivity and silk attractiveness. We exposed 26 virgin females, from 2 to 28 days after the final molt, to males offering a nuptial gift. Female sexual receptivity was age dependent and increased with adult female age. Females over 15 days from adulthood accepted more gifts than younger females, but the latency of female gift acceptance was not affected by female age. Female sexual receptivity is synchronized with chemical attractiveness, suggesting that females' pheromone release is adjusted at a particular mating age. We suggest that young virgin females may invest more in foraging and maturing gonads than in mating, accounting for the delay in receptivity and chemical attractiveness.
Sexual dichromatism and sexual dimorphism of body size are reasonably well studied in butterflies. Sexual size dimorphism of color pattern elements, however, is much less explored. The object of this study is Heliconius, a genus of butterflies well known for the coevolution between mate color preferences and mimicry. Given the sexual role of wing coloration, we investigated the existence of sexual size dimorphism in the wing color elements of a mimetic pair-Heliconius erato phyllis Fabricius and Heliconius besckei Ménétriés-and analyzed the allometric patterns of these traits. Correlation between size of elements in the dorsal and ventral wing surfaces were also estimated. In both species, three out of four elements were larger in males, but the non-dimorphic element was not the same. With regard to the allometric patterns, our most important finding was that smaller males of one species have proportionally larger yellow bars. This is the first study specifically concerning quantitative sexual dimorphism in the coloration of this well-known genus of butterflies and it opens new prospects to investigate sex-related natural selection and sexual selection of color pattern elements.
O objetivo deste artigo é sintetizar conceitos-chave sobre especiação e servir de auxílio para professores e alunos de ciências biológicas. Adotou-se uma abordagem que estimula o questionamento como forma de interligar diferentes temas. Partindo-se dos conceitos de espécie, são tratados: a especiação alopátrica, o isolamento reprodutivo como um subproduto da divergência, o papel da seleção natural, reforço, hibridização, o papel da seleção sexual, especiação simpátrica, especiação parapátrica e mecanismos de isolamento.
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