Sensing the Plant Surface Prior to Feeding and Oviposition: Differences in External Ultrastructure and Function Among Tarsi of Heliconius erato.

Adult foretarsi of Heliconius erato Linnaeus (Lepidoptera, Nymphalidae) are reduced in size and are not used for walking. Foretarsi of the female have specialized sensilla that are presumably used to identify the host plant, by drumming. The mid- and hind tarsi also bear sensilla in both sexes, but these have not been described in detail, nor has their chemosensory function been determined. We described and compared the tarsi of H. erato under light and scanning electron microscopy. Behavioral experiments showed that differences in the shape, number, and size of sensilla were related to feeding and oviposition behaviors. Two types of sensillum (chaeticum and trichodeum) were found in similar numbers and size on the mid- and hind tarsi of both sexes. Sensilla on the female foretarsi act in host-plant site selection, strongly affecting oviposition rates when isolated. Male foretarsi lack sensilla, which may have been selected against due to the absence of function and thus lost. Sensilla on the mid- and hind tarsi are involved in sugar detection in both sexes, responding to an effective dose of sucrose (ED50) near 0.01 M, and therefore might be used to identify food resources when the butterflies settle on flowers.

Diversification of the silverspot butterflies (Nymphalidae) in the Neotropics inferred from multi-locus DNA sequences.

The tribe Heliconiini (Lepidoptera: Nymphalidae) is a diverse group of butterflies distributed throughout the Neotropics, which has been studied extensively, in particular the genus Heliconius. However, most of the other lineages, such as Dione, which are less diverse and considered basal within the group, have received little attention. Basic information, such as species limits and geographical distributions remain uncertain for this genus. Here we used multilocus DNA sequence data and the geographical distribution analysis across the entire range of Dione in the Neotropical region in order to make inferences on the evolutionary history of this poorly explored lineage. Bayesian time-tree reconstruction allows inferring two major diversification events in this tribe around 25mya. Lineages thought to be ancient, such as Dione and Agraulis, are as recent as Heliconius. Dione formed a monophyletic clade, sister to the genus Agraulis. Dione juno, D. glycera and D. moneta were reciprocally monophyletic and formed genetic clusters, with the first two more close related than each other in relation to the third. Divergence time estimates support the hypothesis that speciation in Dione coincided with both the rise of Passifloraceae (the host plants) and the uplift of the Andes. Since the sister species D. glycera and D. moneta are specialized feeders on passion-vine lineages that are endemic to areas located either within or adjacent to the Andes, we inferred that they co-speciated with their host plants during this vicariant event.

O estágio de ovo dos Heliconiini (Lepidoptera, Nymphalidae) do Rio Grande do Sul, Brasil

Based upon light and scanning electron microscopy, the external morphology of the egg stage is described and illustrated for the following Heliconiini (Lepidoptera, Nymphalidae) from Rio Grande do Sul State, Brazil: Agraulis vanillae maculosa (Stichel, 1907), Dione juno juno (Cramer, 1779), Dione moneta moneta Hübner, 1825, Dryadula phaetusa (Linnaeus, 1758), Dryas iulia alcionea (Cramer, 1779), Philaethria wernickei (Röber, 1906), Eueides isabella dianasa (Hübner, 1806), Eueides aliphera aliphera (Godart, 1819), Heliconius ethilla narcaea Godart, 1819, Heliconius besckei Ménétriés, 1857, and Heliconius erato phyllis (Fabricius, 1775). A dichotomic key is provided for their identification, based upon differences at the levels of generic and ultrastructural morphology, and variation in host-plant use.

Utilizando-se da microscopia de luz e de varredura, são descritos e ilustrados os ovos dos seguintes Heliconiini (Lepidoptera, Nymphalidae) do Rio Grande do Sul (Brasil): Agraulis vanillae maculosa (Stichel, 1907), Dione juno juno (Cramer, 1779), Dione moneta moneta Hübner, 1825, Dryadula phaetusa (Linnaeus, 1758), Dryas iulia alcionea (Cramer, 1779), Philaethria wernickei (Röber, 1906), Eueides isabella dianasa (Hübner, 1806), Eueides aliphera aliphera (Godart, 1819), Heliconius ethilla narcaea Godart, 1819, Heliconius besckei Ménétriés, 1857 e Heliconius erato phyllis (Fabricius, 1775). Com base em diferenças morfológicas genéricas e ultraestruturais, associadas aos padrões de uso das plantas hospedeiras, elaborou-se uma chave dicotômica para a identificação das espécies.

O estágio de ovo dos Heliconiini (Lepidoptera, Nymphalidae) do Rio Grande do Sul, Brasil

Based upon light and scanning electron microscopy, the external morphology of the egg stage is described and illustrated for the following Heliconiini (Lepidoptera, Nymphalidae) from Rio Grande do Sul State, Brazil: Agraulis vanillae maculosa (Stichel, 1907), Dione juno juno (Cramer, 1779), Dione moneta moneta Hübner, 1825, Dryadula phaetusa (Linnaeus, 1758), Dryas iulia alcionea (Cramer, 1779), Philaethria wernickei (Röber, 1906), Eueides isabella dianasa (Hübner, 1806), Eueides aliphera aliphera (Godart, 1819), Heliconius ethilla narcaea Godart, 1819, Heliconius besckei Ménétriés, 1857, and Heliconius erato phyllis (Fabricius, 1775). A dichotomic key is provided for their identification, based upon differences at the levels of generic and ultrastructural morphology, and variation in host-plant use.

Utilizando-se da microscopia de luz e de varredura, são descritos e ilustrados os ovos dos seguintes Heliconiini (Lepidoptera, Nymphalidae) do Rio Grande do Sul (Brasil): Agraulis vanillae maculosa (Stichel, 1907), Dione juno juno (Cramer, 1779), Dione moneta moneta Hübner, 1825, Dryadula phaetusa (Linnaeus, 1758), Dryas iulia alcionea (Cramer, 1779), Philaethria wernickei (Röber, 1906), Eueides isabella dianasa (Hübner, 1806), Eueides aliphera aliphera (Godart, 1819), Heliconius ethilla narcaea Godart, 1819, Heliconius besckei Ménétriés, 1857 e Heliconius erato phyllis (Fabricius, 1775). Com base em diferenças morfológicas genéricas e ultraestruturais, associadas aos padrões de uso das plantas hospedeiras, elaborou-se uma chave dicotômica para a identificação das espécies.

Geographical variation in larval host-plant use by Heliconius erato (Lepidoptera: Nymphalidae) and consequences for adult life history

Adult body size, one of the most important life-history components, varies strongly within and between Heliconius erato phyllis (Lepidoptera: Nymphalidae) populations. This study determines if this variation is caused by geographical changes in host-plant used by the larval stage, whose reproductive parameters are influenced by female body size, with estimates of the corresponding heritability. The variation in adult body size was determined together with a survey of passion vine species (Passifloraceae) used by the larvae in seven localities in Rio Grande do Sul State: three located in the urban area of Porto Alegre and Triunfo Counties, two within Eucalyptus plantations (Barba Negra Forest, Barra do Ribeiro County, and Águas Belas Experimental Station -- Viamão County), one in a Myrtaceae Forest (Itapuã State Park -- Itapuã County) and one in the Atlantic Rain Forest (Maquiné Experimental Station -- Maquiné County). Effects of female body size on fecundity, egg size and egg viability were determined in an outdoor insectary. Size heritability was estimated by rearing in the laboratory offspring of individuals maintained in an insectary. The data showed that adults from populations where larvae feed only upon Passiflora suberosa are smaller than those that feed on Passiflora misera. The larvae prefer P. misera even when the dominant passion vine in a given place is P. suberosa. Fecundity increases linearly with the increase in size of females, but there is no size effect on egg size or viability. Size heritability is null for the adult size range occurring in the field. Thus, the geographical variation of H. erato phyllis adult size is primarily determined by the type, corresponding availability and quality of host-plants used by the larval stage. Within the natural size range of H. erato phyllis, the variation related to this caracter is not genetically based, thus being part of H. erato phyllis phenotypic plasticity.

Os adultos de Heliconius erato phyllis (Lepidoptera: Nymphalidae) variam acentuadamente em relação ao tamanho corporal. Neste trabalho, avalia-se a hipótese de que tal variação se deva em parte a diferenças qualitativas do recurso alimentar da fase larval (passifloráceas) existentes em campo. Em adição, identifica-se como a performance reprodutiva das fêmeas é influenciada pelo tamanho, sendo também estimada a herdabilidade dessa característica. Determina-se a variação espacial do tamanho corporal em sete populações de H. erato phyllis do Estado do Rio Grande do Sul (RS), situadas em ambientes urbanos (3), matas de Eucalyptus (2), mata de Mirtáceas (1) e Mata Atlântica (1), e relaciona-se tal variação ao recurso larval utilizado. Em insetário, quantifica-se a influência do tamanho das fêmeas nos parâmetros fecundidade, viabilidade e tamanho do ovo. A herdabilidade do tamanho foi estimada por intermédio da criação, em laboratório, da prole de indivíduos mantidos em insetário. Os adultos das populações cujas larvas utilizaram unicamente Passiflora suberosa foram significativamente menores em relação às que utilizaram Passiflora misera. As larvas foram encontradas preponderantemente sobre P. misera, mesmo quando P. suberosa foi a espécie predominante em um dado local. Dentre os parâmetros de performance reprodutiva estudados, apenas a fecundidade teve relação direta com o tamanho. A estimativa da herdabilidade para o tamanho foi zero. Assim, confirma-se a importância do recurso alimentar larval na determinação da variabilidade do tamanho dos adultos. Tal variação é parte da plasticidade fenotípica das populações naturais de H. erato, sendo a contribuição genotípica pouco expressiva neste caso.

Geographical variation in larval host-plant use by Heliconius erato (Lepidoptera: Nymphalidae) and consequences for adult life history

Adult body size, one of the most important life-history components, varies strongly within and between Heliconius erato phyllis (Lepidoptera: Nymphalidae) populations. This study determines if this variation is caused by geographical changes in host-plant used by the larval stage, whose reproductive parameters are influenced by female body size, with estimates of the corresponding heritability. The variation in adult body size was determined together with a survey of passion vine species (Passifloraceae) used by the larvae in seven localities in Rio Grande do Sul State: three located in the urban area of Porto Alegre and Triunfo Counties, two within Eucalyptus plantations (Barba Negra Forest, Barra do Ribeiro County, and Águas Belas Experimental Station -- Viamão County), one in a Myrtaceae Forest (Itapuã State Park -- Itapuã County) and one in the Atlantic Rain Forest (Maquiné Experimental Station -- Maquiné County). Effects of female body size on fecundity, egg size and egg viability were determined in an outdoor insectary. Size heritability was estimated by rearing in the laboratory offspring of individuals maintained in an insectary. The data showed that adults from populations where larvae feed only upon Passiflora suberosa are smaller than those that feed on Passiflora misera. The larvae prefer P. misera even when the dominant passion vine in a given place is P. suberosa. Fecundity increases linearly with the increase in size of females, but there is no size effect on egg size or viability. Size heritability is null for the adult size range occurring in the field. Thus, the geographical variation of H. erato phyllis adult size is primarily determined by the type, corresponding availability and quality of host-plants used by the larval stage. Within the natural size range of H. erato phyllis, the variation related to this caracter is not genetically based, thus being part of H. erato phyllis phenotypic plasticity.

Os adultos de Heliconius erato phyllis (Lepidoptera: Nymphalidae) variam acentuadamente em relação ao tamanho corporal. Neste trabalho, avalia-se a hipótese de que tal variação se deva em parte a diferenças qualitativas do recurso alimentar da fase larval (passifloráceas) existentes em campo. Em adição, identifica-se como a performance reprodutiva das fêmeas é influenciada pelo tamanho, sendo também estimada a herdabilidade dessa característica. Determina-se a variação espacial do tamanho corporal em sete populações de H. erato phyllis do Estado do Rio Grande do Sul (RS), situadas em ambientes urbanos (3), matas de Eucalyptus (2), mata de Mirtáceas (1) e Mata Atlântica (1), e relaciona-se tal variação ao recurso larval utilizado. Em insetário, quantifica-se a influência do tamanho das fêmeas nos parâmetros fecundidade, viabilidade e tamanho do ovo. A herdabilidade do tamanho foi estimada por intermédio da criação, em laboratório, da prole de indivíduos mantidos em insetário. Os adultos das populações cujas larvas utilizaram unicamente Passiflora suberosa foram significativamente menores em relação às que utilizaram Passiflora misera. As larvas foram encontradas preponderantemente sobre P. misera, mesmo quando P. suberosa foi a espécie predominante em um dado local. Dentre os parâmetros de performance reprodutiva estudados, apenas a fecundidade teve relação direta com o tamanho. A estimativa da herdabilidade para o tamanho foi zero. Assim, confirma-se a importância do recurso alimentar larval na determinação da variabilidade do tamanho dos adultos. Tal variação é parte da plasticidade fenotípica das populações naturais de H. erato, sendo a contribuição genotípica pouco expressiva neste caso.