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U.S. Fish and Wildlife Service (1991)
gives the most complete information regarding
the ecology of this species. Adults
are active at night (Schweitzer and Master
1987, Peck and Kaulbars 1987), searching for
carrion on which to feed and lay eggs; they
are occasionally attracted to lights. These
beetles seek out large carcasses (up to 300 g)
of mostly birds and mammals, although carrion
sources between 50 and 200 grams are
apparently adequate for rearing their young
(Fig. 107) (Schweitzer and Master 1987).
Nicrophorus americanus, like many
other Nicrophorus species, provides parental
care for its young. Kozol, Scott, and Traniello
(1988) demonstrated that carrion was
prepared by the parents for the larvae in a
fashion similar to that described for other
Nicrophorus species. Nicrophorus americanus
may cooperate in burying carrion, but individuals
of both sexes are capable of burying
carrion alone. The carrion is buried, shaved of
fur or feathers, rolled into a ball, and treated
with anal and oral secretions that favorably
THE CARRION BEETLES OF NEBRASKA 63
Fig. 107. Adult Nicrophorus americanus on a kangaroo rat in west central Nebraska. Photo by M. L. Jameson.
alter the decay process. The female lays
eggs in the soil near the carcass, and larvae
hatch within a few days and move toward the
carcass. The larvae are first fed regurgitated
food by both the male and female parents.
The larvae grow rapidly and are soon able to
feed themselves. Approximately two weeks
after burial of the carrion, the larvae complete
their development and pupate in the
soil nearby. Adults emerged from the pupal
stage from 48 to 65 days later.
They observed further that, in laboratory
studies, reproductive success (measured
by total brood weight and by the number of
tenerals eclosed) is significantly correlated
with carcass size as has also been shown
in laboratory broods of N. orbicollis (Wilson
and Fudge 1984). The negative correlation
between the number of adults reared per
brood and their average weight suggested
that N. americanus parents make a tradeoff
between a larger number of small offspring
or a smaller number of large offspring. The
results of this tradeoff may depend on carcass