The oak hawkmoth (Marumba quercus) is a remarkably large nocturnal moth, with a robust body and a wingspan of 10 cm. Its entire body and wings are covered with brown hair adding pale or whitish areas of variable extent. The wings are long and narrow, the forewings being longer than the hindwings, and their outer margins are wavy. The front of the forewings displays transversal bands of brown shades leaving a wide, pale band in the centre, while that of the hindwings is also brown but lacking from bands and with a red wine-coloured hue at discal cell. Males and females differentiate mostly by their antennae, pectinate in males and simple in females.
Whilst the adult is a spectacular butterfly, the caterpillar is not far behind. In first stages the caterpillar is slender, green with many small white spines and a long, orangish caudal horn having short dark spines. The caterpillar has 3 pairs of legs at the front and 4 pairs of pseudopodia at the back. As the caterpillar grows and overcomes stages, its body grows, the white spines become small warts, and the initially green head adds 2 white, top-down parallel lines. In the final stage before the chrysalis that is shown in the image, the caterpillar reaches 8 cm in length. It has a very elegant blue-green or turquoise body that is dotted with multiple small white warts and with 7 oblique white lines on each side, 4 wider and 3 thinner between the previous ones, everyone crossing 2 segments corresponding to the abdomen, the last line connecting with the caudal horn that’s characteristic of the caterpillars of the sphinxes. On the sides of every segment there is also a small, surrounded by black, white ocellus.
The caterpillars of the oak hawkmoth feed on leaves of any species of the Quercus genus, so those of holm oak, kermes oak, cork oak or oak, not just oak leaves as its common name indicates. The caterpillars feeding on holm oak leaves display a greyish green, while those feeding on oak display a clearer green.
Both adults and caterpillars are cryptic despite their size and colours; adults can be mistaken as dry leaves due to the wavy margins of their wings and their uneven brown colour, while the caterpillars have a similar green shade to that of the leaves of Quercus they feed on, and their oblique white lines break the outline of the body.
[photo Florenci Vallès]