Page 367 - The Book of Caterpillars: A Life-Size Guide to Six Hundred Species From Around the World

MOTH CATERPILLARS

FAMILY Saturniidae
DISTRIBUTION Across Europe and Asia, excluding southern Asia
HABITAT Beech forests, mixed conifer-deciduous forests, and among
deciduous trees along rivers within otherwise coniferous forests
HOST PLANTS European Beech (Fagus sylvatica), birch (Betula spp.), Alder
(Alnus glutinosa), Goat Willow (Salix caprea), Mountain Ash
(Sorbus aucuparia), and oak (Quercus spp.)
NOTE Caterpillar with striped projections when young but
cryptic when mature
CONSERVATION STATUS Not evaluated, but common

ADULT WINGSPAN
2⅜–3 ⁄ (60–84 mm)
CATERPILLAR LENGTH
2⅜ in (60 mm)
AGLIA TAU
TAU EMPEROR 365

(LINNAEUS, 1758)

Tau Emperor caterpillars hatch from eggs that the female
moth lays at di erent strata of the forest, dispersing them by

night in small clusters on the leaves and shoots of host trees.
While in the early instars, the green caterpillars have several
long, red-and-white dorsal projections that probably protect
them to some extent from being swallowed by birds; the later
instars are cryptic. The larvae have only four instars under good
conditions but will molt into additional instars if conditions are
not optimal. There is a single generation per year, and the pupa
overwinters inside a cocoon.

Tau Emperor males y fast and erratically when the sun is out
in early spring, looking for freshly emerged females, which are,
unlike males, nocturnal. Mating occurs during the day, when
males, using pheromone trails and visual cues, find a newly
eclosed female still sitting near her cocoon. Currently, four
species in the genus Aglia are recognized, all of which are quite Actual size
similar. Aglia tau has by far the widest distribution.

The Tau Emperor caterpillar is green with a
white subspiracular stripe and beige spiracles.
Its wavy shape dorsally is formed by pronounced
segmentation, resembling the edge of a leaf. The
minute, short, white spines and hairs throughout
the body add to the leaf resemblance, as do the
white, parallel, vein-like lines that lead o the white,
longitudinal subspiracular line at a 45-degree angle.