Mutualism

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Mutualism

• Mutualism (/)
• Obligate
• coevolved
• necessary for the survival of both species
• Facultative
• Beneficial but not absolutely essential to
  survival of the species.

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Obligate mutualism E.g., figs fig wasps
A receptacle
Female lays only a few eggs in flower Yucca dont
have resources to develop all flowers into
fruit C. 85 receptacles are aborted and dropped.
Those with too many wasp larvae.
Larvae seed eaters
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Yucca moth phylogeny
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Ants and Bullshorn Acacia

• Pseudomyrmex sp. (acacia ants)
• obligate mutualists
• Plant benefits
• Exclusive use of space
• Protection from herbivory
• Ant benefits
• Living space in thorns.
• Plant products
• Foliar nectaries sugar
• Beltian bodies oils and protein.

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Experimental evidence for this mutualism example

• Ants improve plant performance.
• Acacias without ants had more herbivorous
  insects.
• Suckers growing from acacia trunks occupied by
  ants lengthened at seven times rate of suckers
  without ants.
• Suckers with ants survived at twice the rate of
  suckers without ants.

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Benefits vegetative growth
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Benefits shoot survival
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Local Plant Protection Mutualism

• (1) Ants and (2) Aspen sunflowers
• Nectar in extrafloral nectaries.
• rich in sucrose and amino acids.
• Relationship counters seed predation
• Experiments Sunflowers without ants 2-4 times
  more seed predation.
• Relationship facultative.
• Late frosts (in spring) periodically kill
  flowering head of sunflowers.