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BULLETIN OF THE UNIVERSITY OF NEBRASKA STATE MUSEUM
and exposes the cream-white pupa (Fig. 56).
The length of the pupal period varies from 12-
17 days. After emerging from the pupa, the
adult becomes sclerotized in about 24 hours,
after which it digs its way out of the subterranean
cell. Adults overwinter beneath the
soil or in areas that afford protection.
Adults feed primarily on fly larvae during
the active decay stage of a carcass when
maggots are usually abundant, but they will
also consume carrion as well. Typically, an
adult N. surinamensis seizes a maggot with
its mandibles, restrains it with its forelegs
placed on either side of the maggot, and
raises its head to lift the struggling maggot
off of the substrate and so prevent it from
pulling away. After easily breaking the integument
of the maggot with its mandibles,
the beetle chews rapidly and extracts the soft
body contents. Young (1985) observed that
adults may, on occasion, consume noctuid
moth larvae and dead insects.
While the adults are predators on maggots
and may feed on carrion to a limited
extent, the larvae normally feed on carrion
upon which they are free living and, in addition,
feed on fly larvae to a limited extent.
During active decay of a carcass, larvae
feed on decomposing flesh and semi-liquid
putrefaction. When maggot feeding, a larvae
seizes a maggot in the mid-region of the body
with the mandibles while the forelegs assist
in immobilizing the prey. After puncturing
the cuticle, the soft contents are consumed.
Necrodes surinamensis is unique among
silphids because it can eject anal fluid as
a spray (rather than an ooze) (Reed 1958,
Ratcliffe 1972, Eisner and Meinwald 1982).
The abdominal tip, which projects beyond
the posterior margins of the elytra, serves
as a revolvable turret by which ejections are
actually aimed (personal observation, Eisner
and Meinwald 1982). Eisner and Meinwald
noted that N. surinamensis is anomalous in
that it expels its aimed, secretory discharges
from the anus (admixed with enteric matter).
Other beetles that spray (i.e., Carabidae)
also discharge from the tip of the abdomen,
but the glands responsible for the spray are
integumental and open beside the anus. According
to Schildknecht and Weis (1962), the
high concentration of ammonia in the spray
is probably derived from decaying, ingested
animal protein and may serve for defense.
Adults are nocturnal and are strongly
attracted to lights at night. And it is for this
reason that I have concerns for the future
welfare of this species. During the mid-
1970s when I conducted extensive research
on the biology of N. surinamensis, this was
an abundant species in the Lincoln, NE,
area both at carrion and at lights. During
the early 1990s, however, I have rarely seen
this insect near the city at lights or at carrion,
even in places where it used to be abundant.
Artificial lighting may be a contributing
factor because I believe that lights decrease
populations of some nocturnally active insects.
Insects are attracted to lights where
they are congregated and easily preyed upon
by vertebrate scavengers such as toads,
opossums, and raccoons. Even if they are
not eaten, they are effectively drawn away
from their natural habitats and, instead of
breeding, die from exposure on hot pavement
or are run over by cars and trucks. I
believe there is a direct correlation between
the electrification of rural America and the
decline of some nocturnal insects.
Genus NECROPHILA
Nerophila Kirby and Spence 1828: 509.
Necrobora Hope 1840: 151.
Necrotropha Gistel 1848: 121.
Eusilpha Semenov-Tian-Shanskij 1891: 299.
Calosilpha Portevin 1920: 396.
Deutosilpha Portevin 1920: 396.
Chrysosilpha Portevin 1921: 538.
Deuterosilpha (misspelling); in Hatch 1928:
112.
Necrophila is a genus consisting of about
20 species (Hatch 1928, Peck and Miller
1993). With the exception of N. americana,
all species are found in Asia and India (Hatch
1928). Necrophila americana is the only species
found in North America. It is broadly