Beetles & hyperdiversity Flashcards
explain the Coleoptera order
- the beetles
- Most speciose insect order
- Defined by elytra (elytron singular)
- massive diversity
coleoptera - explain their elytra
- elytra are forewings used for armor
- Hindwings only used for flight and they fold under elytra when not in use
- Not greatest flyers (vs odonatan, hymenoptera, diptera)
- Sacrifice flight efficiency for armor/protection
coleoptera - massive diversity
By far more named species than any other group of organisms
coleoptera: massive diversity - why are there so many beetles
- Apparently evolved with the Angiosperms, flowering plants
- Most speciose lineages are phytophagous (plant eating)
- But not clear why so many more beetles than other groups
what do beetles do?
- Beetles attack plants (usually as larvae)
- Beetles are predators
- Beetles are scavengers
explain rarefaction curves
- method used to estimate beetle species
- the curve leveling off allows us to know the estimate total diversity
beetle families - Carabidae
- ground beetles
- Generalist predators
- Often found under rocks, logs
- Catch in pitfall traps
beetle families - Staphylinidae
- Rove beetles
- Short elytra, exposed abdomen
- Elongate ‘squirmy’ form, sometimes hold abdomen up ‘scorpion style’
- Speciose
- Typically, hunters or scavengers
- found under rocks, litter, etc. (also, pitfalls)
beetle families - Scarabaeidae
- superfamily
- Many are dung beetles, the rest feed on plants
- Many have elaborate horns for male-male competition
- Can fold/unfold antennae
beetle families: scarabaeidae - Dung beetles
- dung is resource – want to sequester it to protect resource for larvae
- Compete with other beetles and esp. flies
- May tunnel under dung to sequester it underground or roll it away
- Ecologically important for scavenging
beetle families - Silphadae
- carrion beetles (also known as burying beetles)
- Nicrophorous species are local – have parental care
- ecologically important for scavenging
beetle families: silphaadae - nicrophorous species
- Dig hole under carcass, carcass falls in and is buried
- Prepare carcass for larvae, stay and defend them
- Often have phoretic mites that kill fly eggs (mutualism) bc flies are competitors for carcass
- Why bury? Protect carcass from other scavengers
beetle families - Lampridae
- fireflies
- Bioluminescence – light production
- Males use light signal for females
beetle families - Elateridae
- click beetles
- Can ‘snap’ their prothorax against the mesosternum to shoot in the air to try to escape predators
- Some tropical spp. are bioluminescent
beetle families - Curculionoidea
- weevils
- Largest insect family, 60,000 described spp.
- Long ‘snout’ (rostrum) with mandibles at end – penetrating drill bit
- Typically plant feeders, some pests
Boring beetles
- boring = drill into wood
- Several families have larvae that bore into wood
- Develops over months-years, so can be transported as larvae in shipping crates, lumber, furniture, etc.
- High potential for invasion
- Larvae tunnel through cambium – cut off tree circulation, kill trees
boring beetles - examples
- Burprestidae (Emerald ash borer)
- Cerembycidae (Asian long horned beetle)
- Curculionidae and Scolytinae (Bark beetle)
boring beetles - Burprestidae
- Emerald ash borer
- likely to wipe out Ash in USA forests
boring beetles - Cerembycidae
- Most Cerembycids bore through dead wood – not really pests
- a few, like Asian long-horned, attack live trees
- long horned beetle is threat to hardwood forests, esp. maple
boring beetles - Curculionidae and Scolytinae
- bark beetles
- Adults bore into trees, oviposit, larvae burrow out through wood girdling the tree by cutting off sap flow
- Also introduce fungus to help digest wood, this further damages the tree
- Beetles produce aggregation pheromones
boring beetles: Curculionidae and Scolytinae - explain their aggregation phermones
the pheromone attract more individuals to overcome resin defenses (single beetle not successful)
boring beetles: Curculionidae and Scolytinae - how can the tree resist
- Tree can resist with resin, but drought-weakened trees are susceptible to the beetles
- Very cold winters (-30 F for 5 days) also keep beetle populations down
boring beetles: Curculionidae and Scolytinae - how does climate change impact the tree’s resistance
- more drought and warmer winters mean more bark beetle damage (less sap, more beetles)
- Destroyed millions of acres of western forest
- Creates huge fire hazard, destroys habitat
beetle families: Curculionoidea - Boll weevil
- major cotton pest
- early target of insecticides: in early 1900’s ~40% of all insecticide was targeted at boll weevil
- Overuse exposed limits, resulted in environmental damage of pesticides
Curculionoidea: Boll weevil - 2 things ppl found that helped pest control
- Discovery of mating pheromone led to mating disruption and also traps for monitoring
- Weevil diapauses in dead cotton stems
Curculionoidea: Boll weevil - how did the knowledge of diapause help pest control
- pesticide treatment right before autumn kills many, more effective than spraying through the summer
- plowing under old stems after harvest further kills the overwintering weevils
