Agraulis vanillae, Patagonia, Arizona, USA – Frank Model
Introduction
The genus Agraulis comprises of 2 known species – vanillae, and a currently un-named species which was discovered in Peru by Lamas in 2003.
Agraulis vanillae is distributed from the USA to Paraguay and Argentina. It is found on most of the larger Caribbean islands, and also occurs on the Galapagos Isles.
Habitats
This species is found mainly in semi-open habitats including forest edges, scrub, roadsides, parks and gardens, at altitudes between sea level and about 1000m.
Lifecycle
The eggs are yellow, and laid singly on the leaves, tendrils and buds of the foodplants.
The caterpillar when fully grown is greyish-black, speckled with cream dots, and covered in black spines. Along the back is a pair of reddish lines, and a broad broken red line runs along each side. It feeds nocturnally on Passiflora and Tetrastylis ( Passifloraceae ).
The chrysalis resembles a twisted dead hanging leaf. It is marbled in shades of olive-brown, with small silvery streaks along the dorsal edge of the wing cases. There is a keel projecting from the thorax, and a row of short knobbly tubercles along the back of the abdomen.
Adult behaviour
Males sometimes imbibe moisture from damp sand or soil, but like the females are more often seen nectaring at Lantana and other red flowers. Unlike many other Heliconiines, they do not sequester pollen.
The courtship behaviour is almost identical to that of Dryadula phaetusa – the male chases after his prospective mate until she settles on the ground. He then flutters and hovers just above her, prior to settling beside her. If she is receptive she remains motionless, and the male then half opens his wings and flutters them very rapidly for a few seconds to direct pheromones towards her antennae. This has the effect of placating her. The male then curves his abdomen around to make contact and copulate.
In cases where the female is unreceptive she outspreads her wings and raises her abdomen. This serves 2 purposes – firstly it acts as a visual rejection signal, and secondly it physically prevents the male from copulating. It is possible that at the same time the female emits pheromones that may carry a chemical repellent to further discourage the male.