Rodrigues D, Moreira G R P
Instituto de Biociências, UFRGS, Av. Bento Gonçalves, 9500, Prédio 43422, CEP 91501-970, Porto Alegre, RS, Brazil.
Braz J Biol. 2002 May;62(2):321-32. doi: 10.1590/s1519-69842002000200016. Epub 2002 Aug 26.
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 Aguas 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 character is not genetically based, thus being part of H. erato phyllis phenotypic plasticity.
成虫体型是最重要的生活史组成部分之一，在红带袖蝶（鳞翅目：蛱蝶科）种群内部和种群之间存在显著差异。本研究旨在确定这种差异是否由幼虫阶段所食用的寄主植物的地理变化引起，其生殖参数受雌虫体型影响，并估计相应的遗传力。通过对巴西南部七个地区幼虫所食用的西番莲属植物（西番莲科）进行调查，同时测定成虫体型的差异：三个地区位于阿雷格里港和特里温福县的市区，两个地区位于桉树林内（巴巴内格拉森林，巴拉多里贝罗县，以及阿瓜斯贝拉斯实验站 - 维亚毛县），一个地区位于桃金娘科森林（伊塔普阿州立公园 - 伊塔普阿县），一个地区位于大西洋雨林（马基内实验站 - 马基内县）。在室外昆虫饲养室中测定雌虫体型对繁殖力、卵大小和卵活力的影响。通过在昆虫饲养室饲养个体的实验室后代来估计体型遗传力。数据表明，幼虫仅以皱叶西番莲为食的种群中的成虫比以苦难西番莲为食的种群中的成虫体型更小。即使在特定地点占主导地位的西番莲属植物是皱叶西番莲时，幼虫也更喜欢苦难西番莲。繁殖力随雌虫体型的增加呈线性增加，但体型对卵大小或活力没有影响。对于野外出现的成虫体型范围，体型遗传力为零。因此，红带袖蝶成虫体型的地理差异主要由幼虫阶段所使用的寄主植物的类型、相应的可获得性和质量决定。在红带袖蝶的自然体型范围内，与该特征相关的变异不是基于遗传的，因此是红带袖蝶表型可塑性的一部分。
