Red Goat Moth (Cossus cossus) Caterpillar Searching for Pupation Site

Recorded on May 4th 2015 at the Atatürk Arboretum of Istanbul University, Bahçeköy, Türkiye.

The individual in the recording most probably belongs to Cossus cossus gueruenensis reported from Asia Minor. The caterpillar has reached its final growth stage as a caterpillar and is frantically searching for a place to burrow itself in the forest floor to become a pupa. Pupation is the final stage of a caterpillar before metamorphosing into adult butterfly form. The developmental transformation in these insects has attracted attention of biologists for a very long time. The following video is an outstanding computer tomography scan demonstration of a butterfly chrysalis metamorphosizing over 16 day period:

The Red Goat Moth caterpillars have a striking ‘goaty’ smell which gives its name. Romans consumed these caterpillars as a delicacy after rearing them with flour diet. Flour is a much more easy to digest food compared to wood and must facilitate faster growth.

In nature, the caterpillar burrows into the trunks of various deciduous trees (see the full list of tree genus the caterpillars feed on at the bottom of the post), and feeds on the wood. Xylophagous feeding behavior has a trade off. Eating wood requires long digestion period required which prevents fast maturation. The larvae can impressively live for up to five years before pupating.

During the long (five years!) feeding period the larvae opens galleries and fermented sap of the host tree runs on the outside. A wide range of other insects including the adult forms of many butterflies are attracted to the sap. In the meantime the larvae are under constant attack from predators. Hiding inside the wood does not guarantee safety from specialized predators such as the Ichneumon wasps who can parasitize insect larvae using their long ovipositors.

The Red Goat Moth is a generalist herbivore feeding on a wide range of decidious temperate forest trees including:

Alnus
Betula
Castanea
Citrus
Cydonia
Fagus
Fraxinus
Juglans
Malus
Olea
Populus
Prunus
Pyrus
Quercus
Salix
Sorbus
Ulmus
Vitis