Conspecific mimics and low host plant availability reduce egg laying by Heliconius erato phyllis (Fabricius) (Lepidoptera, Nymphalidae)

• Autor(a) principal: Mugrabi-Oliveira,Elna
• Data de Publicação: 1996
• Outros Autores: Moreira,Gilson R.P
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista Brasileira de Zoologia (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81751996000400014
• topic: Heliconius; Passiflora; oviposition behavior; egg-load assessment; plant density recognition

Oviposition response of Heliconius erato phyllis (Fabricius, 1775) (Lepidoptera, Nymphalidae) to variation in host plant availability, Passiflora suberosa Linnaeus (Passifloraceae), and to presence of conspecific eggs and larvae was determined through choice experiments performed under insectary conditions. Freeze dried, painted eggs and larvae were used as mimics for testing presence of conspecific effects. Females laid more eggs on intact P. suberosa shoots without conspecifics than on those with H. erato phyllis egg and first instar mimics in both simultaneous and sequential choice trials. Oviposition response to variation in host plant availability was determined through no-choice trials, under host plant densities varying from 0.3 to 8.3 plants per female. Number of eggs laid per plant decreased exponentially with an increase in plant availability. On the contrary, daily oviposition rates (eggs /female/day) increased with an increase in plant number, and levelled off when the number of plants available for oviposition was greater than potential fecundity of females. Thus, it is inferred from the results that females assess egg and larval load and prefer to lay eggs on shoots free from conspecifics. It is also inferred that they are able to recognize plant abundance and are unwilling to lay more than one egg per shoot even when host availability is scarce, as judged by reduction in daily oviposition rates under low host plant number. The consequences of laying isolated eggs on P. suberosa shoots are discussed from the viewpoint of intraspecific competition in the larval stage of H. erato phyllis.