Obligate mutualism


Table of Contents for: Obligate mutualism

Obligate mutualism is where two different living things cannot survive without each other.

Where one organism cannot survive without the other, this is called obligate mutualism and the term is easy to remember because both organisms are obligated, or forced to, rely on one another.

Examples of Obligate mutualism

a) Acacia ants

Acacia ants (Pseudomyrmex ferruginea) inhabit the bullhorn acacia (or bullhorn wattle; Vachellia cornigera).
The ants obtain food and shelter, and the acacia depends on the ants for protection from browsing animals, which the ants drive away.
Neither member can survive successfully without the other, also exemplifying obligative mutualism.”

‘Mutualism – biology’ Britannica [iv]

b) Ficus macrophylla and fig wasps

Fig Wasp on a Fig leaf.

Ficus macrophylla, commonly known as the Moreton Bay Fig, comes from Australia and has an obligate mutualism with fig wasps.

This means that the figs are only pollinated by fig wasps, and fig wasps can only reproduce in fig flowers:

Figs have an obligate mutualism with fig wasps, (Agaonidae);
figs are only pollinated by fig wasps, and fig wasps can only reproduce in fig flowers.
Pleistodontes froggatti can only reproduce in the syconia of its host species, the Moreton Bay Fig, Ficus macrophylla.”

‘Pleistodontes froggatti’ Wikipedia [vi]

There were totally failed attempts at growing the plant in Hawaii and California until they introduced the correct wasps.

c) Fungi that live on plant roots

Obligate mutualism…
Another example is the mycorrhizal (pronounced ‘my-core-rye-zal’) fungi that live on plant roots.
The plant roots take advantage of the increased water uptake from the fungi, and the fungi get nutrients from the plant.”

‘Mutualistic Relationships: Examples’ & Types’ Study.com [i]

How does evolution explain Obligate mutualism?

The quote below mentions ‘Wolbachia’ which is a genus of intracellular bacteria that infects mainly arthropod species:

Wolbachia is best known as a facultative endosymbiotic parasite, manipulating host reproduction.
However, it has also evolved as an obligate mutualist at least twice.
In a recent paper, Pannebakker et al. identify a possible mechanism for such a transition from facultative parasitism to obligate mutualism in a parasitic wasp in which Wolbachia are required for producing eggs (oogenesis).
Their proposed mechanism suggests that compensatory evolution in the host to counter the harmful effects of Wolbachia is the basis of this evolutionary transition.”

‘The evolution of obligate mutualism: if you can’t beat ’em, join ’em’ Cell.com [ii]

Here’s another example of obligate mutualism and trying to explain the relationship within an evolutionary context:

Joshua trees… are the sole host plants for two species of yucca moths, which lay their eggs in Joshua tree flowers and nowhere else.
The Joshua trees, in turn, completely rely on these yucca moths for pollination.
Theirs is a classic case of obligate mutualism…
the two species of Joshua trees, the eastern Joshua tree (Yucca jaegeriana) and the western Joshua tree (Y. brevifolia), overlap, which means it is also the only place we know of where their two sister species of moth pollinators (Tegeticula antithetica and T. synthetica) coexist.
The two moth species look almost exactly the same, but differ slightly yet significantly in body size and in the length of their ovipositors (egg-laying organs).
In fact, the shape and length of the flower styles of each Joshua tree species perfectly match the differences in the body length and ovipositor sizes of the two moth species.
Pure coincidence? Or is some other force, like natural selection, at play?…
it appears that natural selection is acting to make moth ovipositors and flower styles match in length.
And while style length is certainly one of the traits under selection, it is not the only one.
Intriguingly, natural selection appears to be maintaining species separation even where the two Joshua tree species overlap and hybridize.
But what specific traits are responsible for sustaining this divergence?

‘Obligate Mutualism Blooms In The Desert by Candace Fallon [iii]
Mutualism: yucca moth eats a few yucca seeds while being protected and then pollinates the Yucca flowers.
In the mutualism between the yucca moth (Tegeticula yuccasella) and the yucca plant (Yucca), moth larvae feed on some—but not all—of the plant’s seeds and use the plant’s seedpods as shelter. In return, adult moths serve as the plant’s pollinator. [v]

Evolution could explain obligate mutualism with the organism changing to suite it’s environment, but I’m not sure it could solve the dilemma of how the relationship started from scratch with the organisms being exclusively dependant on each other.

How does Creation explain Obligate mutualism?

Creation allows for changes to happen, for example look at the diversity within dogs, but they are still all dogs.
In Creation the power to change has always been within the DNA, therefore the organism can change to keep up with deeper throated flowers (for example).
The concept of having the two organism’s being totally dependant upon each other could have been programmed in from the very start by an ‘Intelligent Designer’.

References:
[i] ‘Mutualistic Relationships: Examples’ & Types’ Study.com
[ii] ‘The evolution of obligate mutualism: if you can’t beat ’em, join ’em’ Cell.com
[iii] ‘Obligate Mutualism Blooms In The Desert by Candace Fallon
[iv] ‘Mutualism – biology’ Britannica
[v] Image: ‘Mutualism – biology’ Britannica
[vi] ‘Pleistodontes froggatti’ Wikipedia

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2 responses to “Obligate mutualism”

  1. Thank you so much! We desperately need all of us pulling on the rope to drag society from error to truth. Darwinism is so ludicrous and yet it is indeed the story of the Emperor’s New Clothes. Once people see and admit it is completely absurd, the sea-change in the ruling paradigm will sweep popular absurdists like Richard Dawkins from the public eye and perhaps the world will begin looking at finding a relationship with God, the Creator?

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