BIOL-3330 Lecture 3: Non-Insect Arthropods

Mites

Mites

A non-insect arthopod. Class: Arachnida, Order: Acari.

What non-insect arthropod is an important part of the soil community beneath remains in later stages of decomposition?

Mites.

List some features of mites, including class and order (4)

• Class: Arachnida, Order: Acari

• Small body, <1mm

• 1 body part with small head attached

• 50,000 species described, >1,000,000 estimated species

Tulgren funnel

A heat lamp over a sample, where small insects and organisms fall through into a collecting jar.

What can mites indicate about a corpse?

Possible origins: Macrochelids are usually found in agricultural areas, therefore flies carrying these will also have agricultural origins.

What are mites predatory on?

Fly eggs and first instars.

List some features of spiders, including order (3)

• Order: Araneae

• 8 legs and two body parts: abdomen and cephalothorax

• Predatory on insects and other arthropods, corpses are a source of insect prey

List some features of Pseudoscorpions, including order (5)

• Order: Pseudoscorpionida

• Small (<5mm), two body parts: abdomen and cephalothorax

• Pedipalps and mouthparts distinctive: “pincher like” chelate

• Common in late stage decay, predatory on other arthropods (bed bugs, roaches)

• Can disperse by phoresy attached to flies

What is phoresy?

Phoresy refers to a symbiotic relationship where one organism, known as the phoront, hitches a ride on another organism, the phoretic, without harming or benefiting it.

List some features of sow bugs/pill bugs, including class and order (4)

• Class: Malacostraca, Order: Isopoda

• Associated with decomposing remains (plant and animal) at all stages

• Possible identifier of location

• 13 species in Ontario

What are sow bugs/pill bugs an indicator of?

Habitat.

List some features of centipedes, including class (4)

• Class: Chilopoda

• predatory on other arthropods (bed bugs, roaches)

• 70 species in Canada and Alaska

• Species commonly found indoors, others largely found outdoors

What are centipedes indicators of?

Habitat.

List some features of millipedes, including class (3)

• Class: Diplopoda

• Live in moist habitats, feed on plants and decomposing animal tissue

• >60 species in Canada and Alaska

What are millipedes indicators of?

Habitat.

List some features of springtails (soil insects), including class and order (3)

• Class: Insecta, Order: Collembola

• Jump using a furcula at the end of the abdomen, live in soil all year

• Feed on decaying matter in damp habitats, seepage underneath decaying corpse is ideal

What are springtails an indicator of?

• Record of a body having been in soil

• Body movement indicator

List some features of silverfish, including class and order (3)

• Class: Insecta, Order: Thysanura

• household insect, pest of stored food products

• Associated with dry remains

What are silverfish an indicator of?

Indoor habitat

List some features of cockroaches, including class and order (3)

• Class: Insecta, Order: Blattaria

• Feed on decaying corpses, commonly at lager stage remains

• Nocturnal household pests

What are cockroaches an indicator of?

Indoor habitat, multi-unit dwelling

List some features of earwigs, including class and order

• Class: Insecta, Order: Dermaptera

• Damp habitats, flying insects, predatory

• Commonly found beneath a corpse for daylight shelter

What are earwigs an indicator of?

Indoor habitat, multi-unit dwelling

List early stage beetles and their activity, including order (7)

• Order: Coleoptera

• Come in all sizes, the most abundant and important order

• Predatory beetles arrive early after death and remain through rotting cycle

• Scarab beetles arrive early after death and remain through rotting cycle

• Ground beetles arrive early after death, prey on other insects

• Histerid beetles (black and shiny) arrive in large numbers and feed on maggots

• Burrying beetles arrive early as larvae and adults, feed on remains and maggots

List beetles that arrive shortly after death using common name and family (5)

• Predatory beetles (Staphilinidae)

• Scarab beetles

• Ground beetles (Carabidae)

• Histerid beetles

• Burying beetles (Silphidae)

List features of carpet/museum beetles, including family (4)

• Family: Dermestidae

• Larvae and adults feed on dried skin, hair, fur

• Common indoor dweller, pest of stored products

• Collection of frass (dung), empty larval casings

What are carpet/museum beetles an indicator of?

Mummified remains.

List features of caddisflies, including order (4)

• Order: Trichoptera

• Immatures live in cases made of sand, twigs, or leaves

• rapid consumer of submerged corpses

• Often found in clothing

What are caddisflies an indicator of?

Aquatic habitats (pools, ponds, lakes, streams)

What is the most useful order of flies?

Diptera

List some features of Diptera (2)

• Two wings, hind wings reduced to halteres

• Primitive flies found on carcasses: crane flies, moth flies, fungus gnats, chironomids

What is the common name for Calliphoridae?

Blowflies.

What flies are first to arrive to a body in cooler climates?

Calliphoridae/blowflies.

What flies are first to arrive in warmer climates?

Flesh flies/Sarcophagidae

Do flesh flies oviposit or give live birth?

They give live birth.

List some features of blowflies (2)

• Deposit eggs in body folds

• Consume carrion, some maggots are predatory on others

List some features of cheese skippers, including family (7)

• Family: Piophilidae

• Small flies, typically of stored products

• Associated with slaughter houses, tanneries

• Maggots jump up to 3 inches to escape predators and migrate to pupate away from corpse

• Usually identified as late arrivers to dried corpses

• Can colonize corpses when large flies are not present

• Often found in graves, have been found in Egyptian mummies

What are cheese skipper an indicator of?

Level of decay

What is simple/ametabolous development?

The immature look like adults, has several moults.

What is incomplete/hemimetabolous metamorphosis?

Larvae are similar to adults but are missing some structures (wings etc).

What is complete/holometabolous metamorphosis?

A full cycle from egg to immature stage to pupae to adult.

What is the immature stage of beetles called?

Grubs.

How are fly maggot instar stages identified?

The presence of 1-3 spiracles.

What is the platron?

The midline of the egg structure, where the larvae split the egg.

What is the ptilinum?

A temporary structure on the adult fly head that swells, breaking the pupal case.

What is hydrogen sulphide (H2S) useful for?

Serves as bait for trapping flies and beetles, a gas released during biochemical fermentation.

What are the major stages of human corpse decomposition?

1. Rigor mortis (stiffness of death)

2. Autolysis (biochemical fermentation)

3. Bloat

4. Putrefaction (rotting)

5. Skeletonization (dry decay)