Lepidoptera and herbivory Flashcards
what are the general features of lepidoptera
- Most primitive moths have chewing mouthparts (like Trichoptera), but vast majority have highly modified, sucking mouthparts in a coiled proboscis
- Holometabolous – full metamorphosis
- Larvae (caterpillars) are important herbivores: often limit plant growth
- Adults are second most important pollinator group (behind bees)
lepidoptera - explain the ecological importance
- Larvae niche: to eat the leaves of plants to grow and pupate
- Adult niche: to eat the nectar of plants for food while pollinating plants
lepidoptera: ecological importance - how do the niches effect plants
- larvae niche: herbivory on plants are not beneficial
- adult niche: pollination is beneficial and helps plants reproduce
explain the Lepidoptera Tree of life
- Most groups pre-date flowers
- But explosion of diversity occurs after the evolution of angiosperms
- “Fenemies” with angiosperms: pollinate as adults, but consume as larvae
lepidoptera - explain their larvae
- caterpillars
- they have prolegs
- important ecology
lepidoptera: larvae - proleg
caterpillars have 6 legs on thorax – can have extra on abdomen
lepidoptera: larvae - ecology
- Massive force for herbivory, structuring plant communities
- Important food source for parasitoids, predatory insects, birds, etc…
lepidoptera - Monarch butterflies
- Migrate from overwintering sites in CA and Mexico through USA over several generations, then return at end of fall
- Rely on milkweed as host plants
lepidoptera - Bombyx mori
- the silk moth
- Domesticated
- Silk from cocoon
- Huge historical importance
- Specialist on mulberry trees
lepidoptera - explain the scales on their wings
- their scales combine pigment and structural color
- Color produced by refraction of light
lepidoptera - what are the function of color in wings
- Crypsis (camouflage)
- Warning coloration
- Fake warning coloration
- Startle predators – eyespots
- Species identity/sexual signaling
lepidoptera: wings - crypsis (camouglage)
- Peppered moth example from England
- Black moth is rare and white one is common
- after industrial revolution (everything became black) , the black one became a more common one with the white one decreasing
- After air quality got better, white one became more common as everything went back to a normal color
lepidoptera: wings - what are the two types of warning coloration
- Mullerian mimicry
- Bastesian mimicry
lepidoptera: wings - define mullerian mimicry
- honest mimicry
- multiple chemically defended species use the same signal
- some insects use similar warning coloration to enhance the signal
lepidoptera: wings - define bastesian mimicy
- fake warning coloration
- some species without chemical defense copy the signal
lepidoptera: wings - honest mimicry examples
- The monarch butterfly
- Viceroy and Milkweed bug
lepidoptera - eyespots
- Crypsis on forewings, hindwings exposed as last resort
- Hindwings are exposed quickly to suddenly startle predator, buy moments for escape
lepidoptera - Some Lepidoptera have camouflaged wings, while others have extremely bright and noticeable wings. Explain how these divergent wing types could each be selected for.
- Bright color – it is selected for when an animal eats a toxic Lepidoptera that has the coloration. Then the predator can avoid the other lepidoptera that has the coloration (even if they are not toxic)
- Camouflaged – it is selected for as the predators are not able to see them
explain Herbivory
- its a major force reducing plant fitness
- not just Lepidoptera
- Almost all caterpillars are herbivores, but not all herbivores are Lepidoptera caterpillars
herbivory - non-lepidoptera herbivore examples
- Hemiptera sap suckers
- Locusts
- Sawflies
- Also many Diptera and coleoptera larvae
explain Herbivory and the co-evolutionary chemical arms race with plants and adaptive radiation
- Insects can eat plants
- Plant evolves chemical defense
- Insect overcomes chemical defense
- Plant evolves more elaborate chemical defense - cycle starts over again
herbivory and co-evolutionary arms race - insect can eat plants
- new ‘adaptive zone’
- insect undergoes ‘adaptive radiation’: evolve into new species to exploit new niche
herbivory and co-evolutionary arms race - plant evolves chemical defense
plant enters new adaptive zone (free of herbivory) and undergoes adaptive radiation
herbivory and co-evolutionary arms race - insect overcomes chemical defense
new adaptive zone – access to all that food
Extreme example of the result of the arms race
Monarch and Milkweed
extreme example of the result of the arms race - what does milkweed produce
- Milkweed produces cardiac glycoside
- Disables Na/K pump and causes a heart attack
extreme example of the result of the arms race - how does the monarch butterfly eat the milkweed
- Monarchs have a mutation in Na/K pump, confers resistance
- Can now sequester plant defensive chemicals, use for defense
extreme example of the result of the arms race - what is the secondary result
Mullerian and Batasian mimicry
extreme example of the result of the arms race - how does this show convergent evolution
Insects from 6 orders have similar Na/K mutation
arms race - explain the evolution of the toxin resistance
- Evolution of toxin resistance uses same three amnio acid substitutions (in alpha subunit of Na pump), despite multiple evolutionary origins in different insect species
- Inserting these into Drosophila makes them resistant
explain the relationship between bullhorn acacia tree and ants
- Plants “paying” ants for private security with room and board
- Tree houses and feeds ants in return for herbivore protection
- The ants on plant get food and a nest, ants then attack any organism that tries to eat the plant
