Transcript Coevolution of Insects and Flowering Plants

Coevolution of Insects and
(Flowering) Plants
Photographs in this presentation © Pearson Education
or Fred M. Rhoades unless otherwise listed in notes.
Coevolution
• Mutual evolutionary influence between two
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species
Insects and flowering plants are coevolved
Which group “led” is in contention
Characteristics of Insects
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Segments fused:
* Head
• Compound eyes
• Mouth parts: sucking,
chewing, laping
• Other paired appendages
* Thorax
• 3 pairs of legs
• Wings: none, 1 or 2 pairs
* Abdomen
• “Visera” (reproduction,
digestion, etc.)
Fig 33.33, part
Nature of wings used
to define insect orders
Characteristics of Insects,
cont.
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Like all arthropods, insects
molt
Complete metamorphism
* Larva (feeding)
* Pupa (metamorph)
* Adult (reproduction)
Incomplete metamorphism
* Immature look like small
adults
* Gradual increase in size
from molt to molt
Excellent web site on evolution
of insect flight (and other insect
facts) at the Hooper Virtual
Micropaleontological Museum
Insect diversity
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Some 30 Orders
Insect evolution
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Arthropods followed plants onto land
Insects evolved on land
First insect in Mid Paleozoic (springtail)
Insect diversity explosion in Late Paleozoic
Plants used for food and shelter
Early seed plant pollen a food source?
Further coevolution with plants in Mesozoic
and Cenozoic
Plant spores and pollen are
wind dispersed
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Spores:
* Bryophytes
* Ferns, etc.
Pollen:
* Gymnosperms (conifers, etc.)
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Exceptions (past and present):
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A few, unusual mosses – Splachnum
Several cycads
Several Gnetophyta
Most flowering plants (but not all)
Splachnum moss grows on dung and spores are dispersed by flies.
All that is seen here is the end of the sporophytes.
Gymnosperms
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Cycads
Gnetophytes
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Some are pollinated
by beetles
Cycads in Univ. of Georgia Botany Dept. Greenhouse
Pollination of Dioon (cycad) by beetles
Flower evolution
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Gymnosperm pollen or ovule predation by beetles
Some pollination occurred
First flowers
* Pistils hold ovules
* Numerous, generalized parts
* Lots of pollen
Later flowers
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Fusion of parts
Tubular
Bilateral symmetry
More colors
Benefits to the plants
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Efficient pollen transfer
More outcrossing
Salmonberry flowers are hummingbird pollinated
Benefits to the pollinators.
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70% of flowers
pollinated by insects
30% of flowers
pollinated by wind, bats,
birds
Benefits
* Pollen
• rich food source
* Nectar
• average ~ 40% sugar
* No benefit? - Trickery
• pseudocopulation
Bee Ophrys – diagram from Charles Darwin
Important pollinating
Insect Orders
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Coleoptera – Beetles
Diptera – Flies
Hymenoptera – Bees, Wasps & Ants
Lepidoptera – Moths & Butterflies
Coleoptera = “sheath-wings”
• Beetles (not Beatles)
• 250,000+ named species
• Chewing mouthparts
• Beetle flowers
* Dull, light color
* Strong odors: fruity,
spicy or fetid
* Pollen, nectar, other
flower parts
Phratora beetle head SEM by Alfred
Köpf - Sonoma State University
Magnolia
Amborella
Skunk Cabbage, Lysichticum
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Diptera = “two-wings”
Flies
85,000+ named species
Most attack animals
Lapping, sucking or sawing
mouthparts
Fly flowers (carrion flies)
* Dull, dark colors
* Fetid odors (dead meat)
* Few pollen or nectar rewards
Blowfly SEMs - “tongue” ↑
← head
Stapelia –
“Carrion Flower” or
“Starfish Flower”
Hymenoptera = “membrane-wings”
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Bees, Wasps, and Ants
110,000+ named species
Chewing & lapping mouthparts
Hairy bodies
Complex social behavior
“Bee” flowers
* bilaterally symmetrical
* short fused petal tubes
* yellows and blues
* patterns visible in UV
* nectar guides
Honey bee head SEM - University of Bath
Bumble bee stealing nectar from a Comfrey flower
Collinsia
Viola
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Lepidoptera = “scaly-wings”
Moths (nocturnal) & Butterflies
(diurnal)
150,000+ named species
Sucking mouthparts
Butterfly & moth flowers
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Like bee flowers, but with:
Long fused petal tubes
Butterfly colors: yellow, red
Moth colors: white or pale, fragrant
Cabbage Butterfly head SEM
- University of Bath
Butterfly on Oregano flowers
Convolvulus
“Morning Glory”
Odonata
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Grasshoppers, etc.
Not pollinating insects
But eat a lot of plant biomass with chewing mouthpart
There are dangers to being a pollinator
Unsuspecting “bee fly” pollinator
gets nabbed for visiting marigold