1. ~ 5,000 aquatic beetles worldwide
Coleoptera
~ 5,000 aquatic beetles worldwide

2. Most live in substrate:
Adults usually leave water temporarily - dispersal.
One time - Elmidae (riffle beetles)
Several times - Dytiscidae, Hydrophilidae

3. Respiration?
1. Self-contained air reserves (Dytiscidae - diving beetle)
2. Transcuticular respiration (gills in larvae)
3. Plastron respiration (adult Dryopidae)
4. Piercing plant tissues (larval Chrysomelidae)
Slender antennae
Hind coxae extend posteriorly
divide first abdominal
segment
Swimming hairs on legs

4. Respiration? 1. Self-contained air reserves (Dytiscids)
2. Transcuticular respiration (gills in larvae)
3. Plastron respiration (adult Dryopidae)
4. Piercing plant tissues (larval Chrysomelidae)

5. Respiration? 1. Self-contained air reserves (Dytiscids)
2. Transcuticular respiration (gills in larvae)
3. Plastron respiration (adult Dryopidae)
4. Piercing plant tissues (larval Chrysomelidae)
Long toed water beetles
Woolly hairs except last
abdominal segment
Short antennae

6. Respiration? 1. Self-contained air reserves (Dytiscids)
2. Transcuticular respiration (gills in larvae)
3. Plastron respiration (adult Dryopidae)
4. Piercing plant tissues (larval Chrysomelidae)

7. Varied life histories
Some larvae occur year round, adults for short period (Psephenidae)
Water pennies
Larvae are aquatic, adults terrestrial

8. Varied life histories
Others occur as larvae and adults year round – Elmidae = riffle beetles
Long antennae
5-segmented tarsi
Crawl on bottom - do not swim
= no swimming hairs on hind legs
5-6 abdominal segments

9. Varied life histories
Others have long adult; larva only around a few weeks - Hydrophilidae
Water scavenger beetles
Adult
3 segmented club antennae
5 segmented tarsi
Larvae
Large mandibles
4 segmented legs

10. Scirtidae = marsh beetles
Adults = terrestrial!
Scirtidae = marsh beetles
Small ( mm)
Larvae have long antennae
4-segmented legs, single claw

11. Beetle pupae are mostly terrestrial
Under stones or logs
Few marine beetles - substrate dwellers

12. Larval morphology = diverse
Sclerotized head capsule
Mandibles, maxillae, labium
Gill-like appendages in some (Gyrinidae = whirligig beetles)

13. Coleoptera

14. Coleoptera

15. Coleoptera

16. Coleoptera

17. The key
2 compound eyes that appear to be divided = Gyrinidae, whirligig beetles

18. Eyes not divided, hind coxae divided into plates that cover abdominal segments 1-2, or 3
Haliplidae, crawling water beetles

19. Hind coxae not expanded into plates, divide abdominal segment 1
Dytiscidae, predaceous diving beetles

20. Hind coxae not dividing abdominal segment 1, antennae clubbed with cuplike segment at base
Hydrophilidae, water scavenger beetles

21. Antennae short with comb-like club, body length 5-6.5 mm
Dryopidae, long-toed water beetles

22. Antennae w/o comblike club, body length < 4.5 mm
Elmidae, riffle beetles