are capable of breeding year-round in
heated buildings. In unheated buildings,
only the adults are likely to be observed dur-
ing cold weather. The confused flower beetle
is more common in the cooler areas of the
world, while they red flour beetle is more
prevalent in warmer climates. However,
both species have become widely distributed
and can sustain populations in any geo-
graphic location. When large beetle popula-
tions exist, both species give flour and other
processed foods a grayish tint. Both species
produce secretions that impart foul odors to
food products. Since the flour beetles live for
over three years, their persistence is impor-
tant in pest management.
Drugstore Beetle: The adult drugstore bee-
tle is 0.15 to 0.35 cm long, light brown to
red-brown, hump-backed, with an invisible
head when viewed from above. The wing
covers have pits arranged in longitudinal
rows or grooves. The antennae have a 3-seg-
mented club. In wooden pallet storage areas
where food residues are absent, identification
should focus on a wood-boring beetle. The
larva is capable of feeding on a whole kernel
of grain, but is more likely to consume
processed grain products. These larvae also
feed on leather, wool and other textiles,
spices, tobacco, and botanical drugs. Since
these larvae can perforate tinfoil and sheet
lead, many kinds of packaging are readily
penetrated. These beetles fly and are
attracted to light.
Cigarette Beetle: The adult cigarette beetle
is 0.15 to 0.35 cm long, light brown with a
humped shape and is similar in appearance
to the drugstore beetle except for smooth
wing covers and saw-like antennae. The eggs
are leading in or near food. The larvae avoid
light through harborage within the food
source. Although this is a pest that attacks
tobacco, it also feeds on grain products, veg-
etables, dried fruits, textiles, spices, botanical
drugs, dried flowers, and books. This insect
is known for its ability to penetrate packages
and is a strong flyer with peak flight activity
in the late afternoon and early evening.
Grain Beetles: The sawtoothed grain beetle
and the merchant grain beetle are similar in
appearance but can be distinguished from
other food pest insects by the six sawlike pro-
jections on each side of the prothorax. The
sawtoothed grain beetle is distinguished
from the merchant grain beetle by its smaller
eyes and the area behind the eyes is larger.
The merchant grain beetle is a weak flyer
and the sawtoothed grain beetle cannot fly.
Since these beetles are not attracted to light,
light traps are not effective monitoring tools.
If a large population develops within a food
ingredient, the resulting food product will
have an off flavor that is objectionable to
humans.
Other grain beetles include the flat grain
beetle and the rusty grain beetle. Both of
these are approximately 0.15 cm long and are
among the smallest grain-infesting beetles.
The antennae of male flat grain beetle are
about the same length as the body; whereas
the female flat grain beetles and both sexes
of the rusty grain beetles have short anten-
nae. The geographic range of the flat grain
beetle is restricted by low temperature and
low humidity and the rusty grain beetle is
more abundant of the two in the wet tropics.
Although these insects cannot feed on intact
grain kernels, those with very small cracks or
defects are vulnerable to attack. The larvae
also feed on dead insects.
Spider Beetles: There are various kinds of
spider beetles that are so named because of
their very small head and prothorax and
large abdomen, causing a resemblance to spi-
ders. They are 0.075 to 0.475 cm long with
voluntary legs that also make them look sim-
ilar to spiders. They are scavengers that are
found feeding on milled or processed grains,
dried fruits, dried meats, animal droppings,
textiles, dead insects, and vertebrates. They