Biology Reference
In-Depth Information
Family SESIIDAE (clearwing moths)
LIFE HISTORY
Adults occur mainly in June and July, and freshly
emerged individuals often bask in morning sunshine on
the trunks of host trees. Eggs are laid in bark crevices or
holes, close to the base of the trunks of poplar trees, and
hatch in about two weeks. Larvae then burrow into the
trees to feed, forming extensive, frass-filled galleries
between the bark and heart wood; the feeding galleries
may also extend into the roots. Larvae continue to feed
for at least two years. Fully fed individuals overwinter
in tough cocoons, formed just below the bark at the base
of infested trees, and pupate in the spring. Adults
emerge several weeks later.
Unusual, wasp-like moths with partly clear (scale-less)
wings and a distinct fan-like anal tuft of scales. The
larvae are stem-borers in shrubs and trees; crotchets on
the abdominal prolegs are arranged into two transverse
bands.
Sesia apiformis (Clerck) ( 548 )
Hornet moth
Associated mainly with black poplar ( Populus nigra )
but also found on other kinds of Populus , including
aspen ( P. tremula ). Sometimes damaging in plantations,
particularly on drought-stressed trees; specimen trees
are also attacked. Palaearctic. Widely distributed in
mainland Europe; present in the British Isles, but rarely
found nowadays and of little or no pest status. An
introduced pest in North America.
DAMAGE
Infested or formerly infested trees are recognized by the
presence at the base of the trunks of adult emergence
holes, each about 8 mm in diameter.
DESCRIPTION
Adult: 35-45 mm wingspan; wings mainly clear, with
brownish scales along the costal margin, brownish veins
and cilia; head yellow; thorax mainly brown, with
tegulae distinctively yellow anteriorly; abdomen mainly
yellow, ringed with brown or black. Larva: up to
50 mm long; yellowish white, with a large reddish-
brown head and a yellowish prothoracic plate. Pupa:
20-30 mm long; dark reddish brown; very plump, with
rows of backwardly directed spines on the abdominal
tergites.
547
548
547 Pupal habitation of poplar leaf miner ( Phyllocnistis
unipunctella ).
548 Hornet moth ( Sesia apiformis ) emergence holes at base
of Populus tree trunk.
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