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DEFOLIATION OF FAGUS CRENATA AFFECTS THE POPULATION
DYNAMICS OF THE BEECH CATERPILLAR,
QUADRICALCARIFERA PUNCTATELLA
NAOTO KAMATA t, YUTAKA IGARASHI I, and SEIJI OHARA 2
_Laboratory of Forest Entomology, Tohoku Research Center
Forestry and Forest Products Research Institute
Nabeyashiki 72, Shimokuriyagawa, Morioka, Iwate 020-01, Japan
2Laboratory of Chemical Conversion, Wood Chemistry Division
Forestry and Forest Products Research Institute
Matshunosato 1, Kukizaki, Inashiki, Ibaraki 305, Japan
INTRODUCTION
In spite of remarkable progress in understanding the ecology of plant-herbivore interactions during the past 90 years,
there is little yet known about the interactions between beeches and their folivores (Edwards and Wratten 1983, Edwards et
al. 1986). Two beeches, Fagus crenata and E japonica, are dominant in the deciduous, broad-leaved forests of the cooltemperature
zone in Japan. They are found from the southern part of Hokkaido, the northernmost main island, to the high
mountains of Kyushu, the southernmost. The beech caterpillar, Quadricalcarifera punctatella (Motschulsky) (Lepidoptera:
Notodontidae), is a monophagous species which feeds on beech leaves and occasionally completely defoliates the trees. V_e
studied its population dynamics and tested the maternal effects hypothesis (Rossiter 1992) and the inducible resistance
hypothesis, assuming that food deterioration occurs in beech following herbivory. A further objective was to determine the
exact mechanisms by which Q. punctatella body size and density decrease after an outbreak has occurred.
Life History and Features of Outbreaks
Q. punctatella is a univoltine species (Igarashi, 1975). The pupa overwinters in the ground, and the adult emerges
from late May to late July with a peak in mid- to late June (Kamata and Igarashi 1995a). Eggs are laid in masses on the
underside of beech leaves, the total number per female being about 350. These are laid in several masses, each containing
20-100 eggs (Kamata and Igarashi 1995b). The larva feeds only on beech leaves and molts 3 or 4 times. The peak appearance
of the last instar larva is in early August.
Serious outbreaks have been recorded since 1917, and outbreaks are known from central Honshu, the main island of
Japan, to southern Hokkaido (Fig. 1) (Kamata and Igarashi 1995d). Most intervals between outbreaks have been 8-12 years
and the average duration 1-4 years. Outbreaks in many regions have been synchronized even though the period of one or the
time between two differed by time and place.
METHODS
Study Sites
Larval density was estimated in Hakkohda (Site A), Hachimantai (Site B), and Appi (Site C), located in the northern
part of Honshu island (Fig. 1). Outbreaks have been recorded at Sites A and B, but no conspicuous defoliation has ever been
recorded in Site C (Kamata et al. in preparation).
Mattson, W.J., Niemelii, P., and Rousi, M., eds. 1996. Dynamics of forest herbivory: quest for pattern and principle. U_IS)_A
For. Serv. Gen. Tech. Rep, NC-183, N.C. For. Exp. Sta., St. Paul, MN 55108.
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