10. Beetles

What is the classification of beetles?

Kingdom: Animalia
→ Phylum: Arthropoda
→ Class: Insecta
→ Order: Coleoptera

What is the general identification of adult beetles? (6 things)

1. Hard body—shape varies from rounded to long and narrow.

2. Hard front wing covers (elytra)—protect the wings and body underneath.

3. Straight join down the back—where the two wing covers meet.

4. Membranous hindwings—usually folded beneath the wing covers.

5. Chewing mouthparts.

6. One pair of antennae—shape varies between species.

What are the 4 main beetle pest groups in this deck?

• Fabric / animal material

• Stored-product

• Timber

• Lawn / soil

Name the 11 beetles/groups in this deck.

Fabric / animal material

1. Carpet Beetle

2. Larder Beetle

3. Hide Beetle

Stored-product
4. Grain Weevil
5. Sawtoothed Grain Beetle
6. Flour Beetle
7. Biscuit / Drugstore Beetle
8. Cigarette Beetle
9. Lesser Grain Borer

Timber
10. Powderpost Beetle

Lawn / soil
11. Scarab Beetle / Curl Grub

What is the beetle life cycle?

Egg → Larva → Pupa → Adult

Complete metamorphosis

Which life stage usually causes most beetle damage?

Usually the larva

But important exceptions include:

• Lesser Grain Borer — adults + larvae damage grain

• Grain Weevils — adults + larvae feed on grain

What is the main pest-control rule for beetles?

Identify beetle → find feeding/damage source → remove/correct source → targeted control

What are the main signs of beetle activity?

Depending on species:

• Live adults/larvae

• Cast skins

• Frass

• Food contamination

• Fabric damage

• Timber exit holes/powder

• Lawn/root damage

Where should you inspect for fabric/animal-material beetles?

• Stored fabrics

• Carpet edges / under furniture

• Lint, hair + dead insects

• Bird/rodent nests + animal remains

Keep it this broad — you do not need ten inspection locations.

Where should you inspect for stored-product beetles?

• Dry stored foods

• Grain / flour / cereals

• Pet food / bird seed

• Food spills + storage bin

What is the key difference between primary and secondary stored-grain pests?

Primary pests
→ can attack whole/intact grain

Secondary pests
→ mainly feed on damaged grain / milled products

Examples:

Primary — Grain Weevil, Lesser Grain Borer
Secondary — Sawtoothed Grain Beetle, Flour Beetle

1. What are the general appearance features of a Carpet Beetle?

• Rounded

• Varied carpet beetle: patchy white, brown/red and yellow colouring

• Black carpet beetle: plain dark brown or black

• Black carpet beetles are more elongated

2. What are the general appearance features of a Larder Beetle?

• Oval body

• First 1/3 of body is dark brown to back

• 2/3 of body is pale yellow

• Back 1/3 is dark brown to black

• Six dark spots in the pale yellow area—three on each side.

What are the general appearance features of a Hide Beetle?

• Dark brown to black above

• Oval body

• Mostly white underside with black patches

• Small pointed spine at the back tip of each wing cover.

What are the general appearance features of a Grain Weevil?

• Brown/reddish to almost black

• Long, narrow body

• Long snout projecting from its head

• Bent, elbow-shaped antennae

• Some species have four reddish spots on their wing covers

What are the general appearance features of a Sawtoothed Grain Beetle

• Reddish-brown

• Long, narrow body

• Head visible from above

• Six saw-like teeth along each side of the thorax

What are the general appearance features of a Flour Beetle?

• Reddish-brown

• Long, narrow body

• Head visible from above

• Antennae thicken towards their tips.

What are the general appearance features of a Powderpost Beetle (Lyctus group)?

• Reddish-brown

• Long, narrow body

• Head visible from above

• Antennae have enlarged, club-like tips.

What are the general appearance features of a Biscuit / Drugstore Beetle?

• reddish-brown

• Oval, hump-backed body

• Head hidden from above

• Grooved wing covers (lines)

• Antennae end in a three-part club.

What are the general appearance features of a Cigarette Beetle?

• reddish-brown

• Oval, hump-backed body

• Head hidden from above

• Smooth-looking wing covers

• Saw-edged antennae without an enlarged end club.

What are the general appearance features of a Lesser Grain Borer?

• Dark reddish-brown

• Long, narrow body

• Head hidden from above beneath a hood-like section

• Antennae end in a loose three-part club.

. What are the general appearance features of an Adult Scarab Beetle?

• Colour varies between species

• Usually a broad, oval body

• Head visible from above

• Antenna tips have flat plates that open like a small fan.

What are the general appearance features of a Curl Grub (Scarab Larva)?

• Creamy-white body with a brown head

• Plump, rounded body

• Usually curled into a C shape

• Three pairs of legs near its head.

Carpet Beetle — Mini Summary

• Scientific group / family — Dermestidae

• Pest type — Fabric / animal material

• Key ID — Small mottled oval adult + hairy larva

• Size — Adults commonly ~2–5 mm; varies

• Colour — Mottled brown/white/yellow/black; varies

• Main food/source — Animal fibres + animal debris

• Damaging stage — Larva

• Main signs — Hairy larvae + cast skins + fabric damage

• Pest-control key — Find larval food source + remove lint/hair/debris + vacuum

Larder Beetle — Mini Summary

1. Scientific name — Dermestes lardarius

2. Family — Dermestidae

3. Pest type — Animal material / scavenger

4. Key ID — Dark beetle + broad pale band with dark spots

5. Size — ~7–9 mm

6. Main food/source — Dead insects/animals + dried animal material

7. Larval ID — Hairy brown larva + 2 curved tail spines

8. Main signs — Adults/larvae + cast skins near animal source

9. Pest-control key — Find + remove dead animal/insect/nest source

The pale band is the easiest adult clue. Larder Beetle larvae commonly develop on dead insects, birds, rodents, animal material and related sources.

Hide Beetle — Mini Summary

1. Scientific name — Dermestes maculatus

2. Family — Dermestidae

3. Pest type — Animal material / scavenger

4. Key ID — Dark beetle + pointed/serrated wing-cover tips

5. Size — ~5.5–10 mm

6. Main food/source — Carrion, hides, dried animal products

7. Larval ID — Dark hairy larva + 2 tail projections

8. Main signs — Larvae/cast skins around animal remains/material

9. Pest-control key — Find + remove animal-material source

A useful comparison with Larder Beetle: Larder = pale band, Hide = dark + pointed serrated rear of wing covers.

Grain Weevil — Mini Summary

I would learn this as a group rather than pretending all Sitophilus are identical.

1. Scientific group — Sitophilus spp.

2. Pest type — Stored whole grain / primary pest

3. Key ID — Long projecting snout

4. Size — ~3–4 mm

5. Colour — Dark brown to black

6. Main food/source — Whole cereal grain

7. Damaging stage — Larva + adult

8. Main signs — Adults in grain + damaged/hollow kernels

9. Pest-control key — Identify infested grain + remove/manage commodity

Rice and maize weevils often show four reddish/orange spots on the wing covers; the long snout is the best group-level ID feature. Australian GRDC guidance identifies Sitophilus weevils as major stored-grain pests.

Memory:

LONG SNOUT + WHOLE GRAIN

Sawtoothed Grain Beetle — Mini Summary

1. Scientific name — Oryzaephilus surinamensis

2. Pest type — Stored food / secondary pest

3. Key ID — 6 saw-like teeth on each side of thorax

4. Size — ~2.5–3.5 mm

5. Colour — Brown

6. Main food/source — Damaged grain + processed dry foods

7. Damaging stage — Larva + adult

8. Main signs — Small flat beetles in packaged/stored food

9. Pest-control key — Find/remove infested food + vacuum residues + sealed storage

The flattened body helps it enter very small gaps in food packaging.

Memory:

FLAT + 6 SAW TEETH + STORED FOOD

Flour Beetle — Mini Summary

6. Flour Beetle — Mini Summary

1. Scientific group — Tribolium spp.

2. Pest type — Stored food / secondary pest

3. Key ID — Elongated reddish-brown beetle + visible head

4. Size — ~3–4 mm

5. Colour — Reddish-brown

6. Main food/source — Flour + milled/damaged grain products

7. Damaging stage — Larva + adult

8. Main signs — Beetles/larvae in flour + food contamination

9. Pest-control key — Remove infested food + deep-clean flour residues

Red and Confused Flour Beetles are very similar; you do not need to separate them unless your course specifically requires it. Both are mainly associated with milled/damaged stored products.

Memory:

REDDISH-BROWN + VISIBLE HEAD + FLOUR

Biscuit / Drugstore Beetle — Mini Summary

1. Scientific name — Stegobium paniceum

2. Pest type — Stored food

3. Key ID — Small reddish-brown + hooded head + lined/grooved wing covers

4. Size — ~2–3.5 mm

5. Colour — Reddish-brown

6. Main food/source — Dry stored foods + spices + plant products

7. Damaging stage — Larva

8. Main signs — Small beetles + holes/contamination in dry foods

9. Pest-control key — Find/remove infested food + vacuum + sealed storage

The lined/striated wing covers are the best distinction from Cigarette Beetle.

Memory:

HOODED HEAD + LINED WINGS + DRY FOODS

Cigarette Beetle — Mini Summary

1. Scientific name — Lasioderma serricorne

2. Pest type — Stored food / dried plant material

3. Key ID — Small rounded reddish-brown + hooded head + smooth wing covers

4. Size — ~2–3 mm

5. Colour — Reddish-brown

6. Main food/source — Tobacco, spices + other dried products

7. Damaging stage — Larva

8. Main signs — Small beetles + contaminated dried products

9. Pest-control key — Find/remove infested product + clean/storage control

Queensland Government describes adults at about 3 mm, with a hunched appearance caused by the downward-bent head.

Memory:

HOODED HEAD + SMOOTH WINGS + TOBACCO/SPICES

Lesser Grain Borer — Mini Summary

1. Scientific name — Rhyzopertha dominica

2. Family — Bostrichidae

3. Pest type — Stored whole grain / primary pest

4. Key ID — Cylindrical body + head hidden under hood-like thorax

5. Size — ~2–3 mm

6. Colour — Dark brown to black

7. Main food/source — Whole cereal grain

8. Damaging stage — Larva + adult

9. Pest-control key — Find/manage infested grain + stored-grain control

This is one of Australia's most important stored-grain pests. Both larvae and adults can damage sound kernels.

Memory:

CYLINDRICAL + HIDDEN HEAD + WHOLE GRAIN

Powderpost Beetle — Mini Summary

1. Scientific group — Lyctinae / Lyctus spp.

2. Pest type — Timber

3. Key ID — Tiny round exit holes + flour-like timber powder

4. Adult size — Usually a few mm; varies by species

5. Colour — Brown to dark brown

6. Main food/source — Starchy sapwood of susceptible hardwood

7. Damaging stage — Larva

8. Main signs — 1–2 mm exit holes + very fine flour-like powder

9. Pest-control key — Identify infested timber + assess/remove/treat susceptible timber

Queensland Government describes Lyctine damage as 1–2 mm round holes plus very fine flour-like powder and notes that larvae can severely damage susceptible hardwood sapwood.

Memory:

TIMBER + TINY ROUND HOLES + FLOUR-LIKE POWDER

Queensland biosecurity issue can occur with Powderpost Beetles?

Lyctus africanus is prohibited matter in Queensland and suspected detections must be reported.

Scarab Beetle / Curl Grub — Mini Summary

Because Scarabaeidae is a huge family, don't memorise one exact adult colour/size for the entire family.

1. Scientific group — Scarabaeidae

2. Pest type — Lawn / soil

3. Key ID — Larva = creamy-white C-shaped grub + brown head + 3 pairs of legs

4. Adult size — Varies by species

5. Adult appearance — Robust oval beetle; varies

6. Main food/source — Larvae commonly feed on grass roots

7. Damaging stage — Usually larva

8. Main signs — Yellow/brown/dead lawn patches + curl grubs in soil

9. Pest-control key — Confirm curl grubs in soil + treat turf/soil where appropriate

Queensland turf guidance stresses that the C-shaped white grub with three pairs of legs is the key larval clue.

Memory:

C-SHAPED GRUB + SOIL + GRASS ROOTS

Which beetles are fabric/animal-material pests? (3)

• Carpet Beetle

• Larder Beetle

• Hide Beetle

Which beetles are stored-product pests? (6)

• Grain Weevil

• Sawtoothed Grain Beetle

• Flour Beetle

• Biscuit / Drugstore Beetle

• Cigarette Beetle

• Lesser Grain Borer

Which are primary whole-grain pests? (2)

• Grain Weevil

• Lesser Grain Borer

Memory:

Can attack intact whole grain

Which are mainly secondary processed/damaged-food pests?

• Sawtoothed Grain Beetle

• Flour Beetle

What is the strongest ID clue for each beetle?

• Carpet — mottled adult + hairy larva

• Larder — pale band with spots

• Hide — dark + pointed/serrated rear

• Grain Weevil — long snout

• Sawtoothed — 6 thoracic teeth

• Flour — reddish-brown + visible head

• Biscuit — hooded head + lined wings

• Cigarette — hooded head + smooth wings

• Lesser Grain Borer — cylindrical + hidden head

• Powderpost — tiny holes + flour-like timber powder

• Scarab — C-shaped white grub

How do you distinguish Biscuit/Drugstore from Cigarette Beetles?

Biscuit / Drugstore

• Lined/grooved wing covers

• Antennae end in 3-segmented club

Cigarette

• Smooth wing covers

• Serrated antennae

Both:
small + reddish-brown + hooded head.

Larder vs Hide Beetle

How do you distinguish Larder from Hide Beetles?

BACK

Larder
→ Broad pale band + dark spots

Hide
→ Mostly dark + pointed/serrated wing-cover tips

Both:
animal-material scavengers + hairy larvae

How do you distinguish the 2 major whole-grain beetles? Grain Weevil vs Lesser Grain Borer

Grain Weevil
→ long snout

Lesser Grain Borer
→ cylindrical + head hidden under hood-like thorax

Both:
→ whole grain / primary pests

What is the main source/damage material for each beetle?

• Carpet — animal fibres/debris

• Larder — dead/dried animal material

• Hide — carrion/hides

• Grain Weevil — whole grain

• Sawtoothed — damaged grain/dry foods

• Flour — flour/milled products

• Biscuit — dry foods/spices

• Cigarette — tobacco/spices/dried products

• Lesser Grain Borer — whole grain

• Powderpost — hardwood sapwood

• Scarab — grass roots/soil

Give the quick memory clue for all 11 beetles.

• Carpet — MOTTLED + HAIRY LARVA

• Larder — PALE BAND + ANIMAL MATERIAL

• Hide — DARK + POINTED REAR

• Grain Weevil — LONG SNOUT

• Sawtoothed — 6 SAW TEETH

• Flour — REDDISH-BROWN + FLOUR

• Biscuit — LINED WINGS

• Cigarette — SMOOTH WINGS

• Lesser Grain Borer — CYLINDRICAL + HIDDEN HEAD

• Powderpost — TINY HOLES + FINE POWDER

• Scarab — C-SHAPED GRUB + LAWN