Dirt, Worms and Maggots
COMMON INSECTS OCCURRING
ON DEAD BODIES
Acari
The Acari, or mites as they also are called, are small organisms, usually
less than a mm in length. Mites occur under the dead body in the soil, during
the later stages of decay. Many mites are transported to the body via other
insects, such as flies or beetles. Other mites are soil dwelling forms which can
be predators, fungus feeders or detritus feeders. Most species will be found in
soil samples from the seepage area under the body.
Aranea
The Aranea or spiders are predators on insects occurring on bodies. No
species is specific to the carrion fauna, and will have limited or no value in
estimation of the PMI.
Diptera
The order diptera contains insects with one pair of wings, the second ones
modified to halteres. About 100,000 species are known to science, many more
awaits discovery. Among the flies we find many members of the carrion fauna. The
larvae of flies lives in very different habitats, also aquatic.
NEMATOCERA
Trichoceridae
Trichocera sp.
or winter-gnats as they also are called because the common species
Trichocera regelationis, T. saltator, T. maculipennis, etc,
fly abundantly in the winter months, although they occur at lower frequencies
throughout the year. The adults resemble small crane-flies. The larvae are
saprophagous and feed on decaying material. Trichocerid larvae constitutes an
important part of the carrion fauna during the winter months, when the blowfly
fauna are missing.
BRACHYCERA
Stratiomyidae
Larvae of Hermetia illucens is recorded eating on human excrement and
human remains. Usually this species occur late in the decomposing process.
CYCLORRHAPHA-ASCHIZA
Phoridae
A large family of flies, containing about 3000 species. They are minute to
medium-sized (0.75-8.00 mm), dull black, brown or yellowish flies of hump-backed
appearance. They are generally bristly and with a very characteristic wing
venation. They run about in an active erratic manner which has earned them the
popular name of scuttle-flies. They breed in a wide variety of decaying organic
material, in addition some develop in fungi and others are parasites. In the
larval stage some species are predators. Several genera is regularly found in
vertebrate carrion e.g. Anevrina, Conicera, Diplonevra,
Dohrniphora, Meopina, Triphleba and some Megaselia
species.
Conicera tibialis also known as the coffin-fly because of its
association with coffined bodies that have been underground for about a year.
Adult C. tibialis is able to bury to a depth of 50 cm in about four days.
At normal grave depths (1-2 m) temperature variation is slight, about 5 degrees
Celsius, so development from egg to adult will take considerable time.
Development can take place independent of season, since the body is buried at
frost free depth.
Syrphidae
These are the familiar hover flies, often camouflaged as wasps or bumble
bees. Among the larvae of syrphids we find the famous rat-tailed maggots. These
occur in filthy water, and may occur in dead bodies.
ACALYPTRATAE
Dryomyzidae
A small group of relatively rare flies. Most species are found in moist
woods. Their larvae occur in decaying organic matter.
Coelopidae
These flies are small to medium-sized, usually dark-brown or black in color,
and have the dorsum of the thorax flattened. The body and legs are very bristly.
They occur along the seashore and are very abundant where seaweeds have washed
up. Occasionally larvae may develop in other organic matter, such as a dead body
which has been lying along the seashore.
Heleomyzidae
Fairly large group of small to medium-sized often brownish flies. Adults are
often found in moist places, larvae in decaying plant or animal matter, or in
fungi.
Sepsidae
Very characteristic flies when alive, the adults occur in large numbers
around excrements and decaying materials, where the larvae develops. The adults
have a peculiar habit of wing-waving. This family have been recorded feeding on
dead human bodies in the time of caseic fermentation and before ammoniacal
fermentation. Eggs of Sepsidae have a very long respiratory horn, often longer
than the egg itself.
Sphaeroceridae
Minute or small dark flies that breed in dung.
Piohilidae
Dark, shining flies. The larvae are scavengers and are often found on dead
bodies that have been lying for a while. Piophila casei is also called
the Cheese-skipper, because the larvae jumps for a considerable height, when
disturbed. This behaviour is probably a defencive tactic against predators.
These flies also infests stored bacon and cheese, which, to the flies, are
almost the same as dried corpses.
Ephydridae
Large group with several common species. They are small to very-small. Adults
are found in moist places: marches, the shores of ponds and streams, and the
seashore. The larvae are aquatic, and many species occur in brackish or even
strongly saline or alkaline water.
Drosophilidae
These are the well-known fruitflies that every biologist have heard about,
and probably most other people too. Minute and small flies, brown, yellow or
grey with brightly colored eyes. The larvae feeds on decaying vegetable matter,
but some also feed on fungi. Some species may occasionally occur on dead humans,
and these are probably feeding on fungi.
Milichiidae
Minute, dark flies. Adults and larvae are scavengers.
CALYPTRATAE
Sarchophagidae
Among the Sarcophagids we find the large flesh-flies with red eyes and a
grey-checkered abdomen. These flies does not deposit eggs, but larvae on the
corpse. They are, together with the Calliphorids, among the first insects to
arrive at the corpse. The larvae are predators on blowfly larvae, as well as
carrion feeders. Many Sarcophagids are feeding on snails and earthworms.
Calliphoridae
These are the famous green-bottles and blue-bottles. There is many species of
blowflies, and each species has their own biology. Some prefers to oviposit in
shade, others in light. Some are mainly urban in their distribution, others
mainly rural.
Fanniidae
Here we find the lesser house-fly, Fannia canicularis among others.
These flies are mainly breeding in faeces, but can also develop in cadavers,
especially if there are patches with semiliquid tissue. The larvae have fleshy
processes all over the body, which assist in floating.
Muscidae
Among this large family we find the common house-fly, Musca domestica.
These flies occur in houses, and are one of the most widely distributed species
on this planet. In warm weather they can complete development in 14 days. Eggs
are laid in decaying material, including, but not limited to, dead bodies.
COLEOPTERA
Several beetles occur on carrion. There exists necrophagous beetles and
predators. The various groups occur in different stages of decomposition.
Staphylinidae
Staphylinids - or rove-beetles may arrive a few hours after death, and remain
active throughout the decomposition process. The adult and larvae feeds on eggs
and larvae of other species. They have a characteristic short elytra.
Dermestidae
Dermestids are common beetles in the later stages of decomposition. Larvae of
dermestids does not occur before the body is dry. The larvae and adults feeds on
dry skin and hairs and other dry dead organic animal matter. Dermestids is a
common stored product pest in homes, and a pest in insect collections and furs
at museums and other places.
Histeridae
Members of this family has short elytra, but not as short as the Staphylinids.
This family occurs wherever there is decay and putrefaction. They have been
found during the bloated, decay and early parts of the dry stage. Both larvae
and adults feed on maggots and puparia. They are usually concealed under the
corpse during daylight, but becomes active in the night. Saprinus and
Dendrophilus occur on dead animals and on air-dried and smoked foods. They
prey on larvae of Dermestes.
Silphidae
In this family we find the Nicrophorus species, well known for their
habit of undertaking small carcasses. Some of the species of Nicrophorus
lives mainly on larger carcasses, and does not bury them. The adults prefer
feeding on maggots, but also feeds on the carrion. The adults feed their larvae
until pupariation. Easton reports that 13 specimens of Necrodes littoralis
was found on the body of a man which had been lying on the North Downs for 17
days in October 1969.
ORIGIN:
http://folk.uio.no/mostarke/forens_ent/common_insects.shtml
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