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47°N - /
8 1
45ON _
44ON _
43ON_
42°N
Figure 2.--State of Michigan, showing the 26 locations where paper birch seed was collected in 1975. The * in southwestern
Michigan indicates the location of the plantation site where the seedlings were planted in 1976. Inset shows the
conterminous 48 states of the US, with Michigan shaded.
trees, and then search for suitable trees to attack. Adults often reattack the same tree until it dies, but from year to year they
attack only those portions that are still living at the time of oviposition. It often takes 2-3 years of successive attack before a
given branch or trunk section dies. Adults are believed to be attracted primarily by host odors given that no pheromone has
yet been discovered for a buprestid (Haack and Slansky 1987, Haack 1992). After mating, females oviposit on the bark
surface of the trunk and branches. After hatching, larvae tunnel through the bark and then feed in the cambial region, scoring
both the inner bark and outer sapwood. Larvae construct meandering galleries throughout the summer months, passing
through four larval instars. In late summer or fall, larvae construct individual pupal chambers in the outer sapwood and there
pass the winter. Pupation occurs the following spring, and soon the adults emerge to renew the cycle.
MATERIALS AND METHODS
As described in Miller et al. (1991), seed was collected from 218 open-pollinated paper birch seedlots (half-sib
families) in 1975, representing 26 Michigan populations; 123 trees from 13 populations in Michigan's Upper Peninsula and
95 trees from 13 populations in Michigan's Lower Peninsula (Fig. 2, Table 1). All parents were growing in natural forests
between latitudes 43.3°N and 47.4°N, and ranged from 5 to 22 m in height, and 9 to 46 cm in diameter (Table 1). The seed
from the 218 half-sib families was planted in February 1976 and grown in the greenhouse for 5 months, held outdoors for 2
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