Natural selection News

Photos of these exquisitely weird spiders are going the rounds

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From Wired Science here.

Persobal favourites are the ones that look like lady bugs or ants or bark or the end of a tree stump:

Myrmarachne is a great word. It aptly describes what this spider is doing: making itself look like a red weaver ant. In fact, the spider is so successful in its disguise that when Bay is out taking pictures of the species, people often ask him why he’s photographing a common ant.

Natural selection explains it all, of course, via a gradual transformation in countless successive generations of the spider over time. Right?

Looking 5% like an ant is exactly what a spider needs for the perfect disguise during the critical first few generations!

It’s just as good as like looking 5% like a cop would be. 😉

7 Replies to “Photos of these exquisitely weird spiders are going the rounds

  1. 1
    Barb says:

    I remember reading an article about the spider that masquerades as an ant back in 2002. Some factoids from the article:

    — To avoid detection, it changes its appearance and behavior so as not to be noticed.
    –The ant has six legs and two antennae, while the spider has eight legs and no antennae. So how does the spider make itself appear to be an ant? Well, it runs about the anthill on six legs, and it projects its other two legs so that they appear to be antennae.
    –Furthermore, the spider moves its two imitation antennae quite credibly. It wiggles them in such a way that they are mistaken for ants’ antennae. This master of disguise can even imitate the jerky, zigzagging walk of ants.
    –Within the anthill the spider receives protection from its natural enemies, including spider wasps.
    –Spiders have better sight than ants, and they can jump, while ants cannot—all of which makes escape easier for them.
    –During the day, the spider does its best to remain undetected within the anthill. At night, however, it is active and will catch ants inside the very anthill in which it makes its home!
    –The male spider may be joined in the anthill by a female companion. She evidences not only faithfulness to her mate but a good deal of initiative as well. She builds a protective cover of threads in the anthill, which protects not only her mate but her eggs too.

  2. 2
    Johnnyfarmer says:

    ….but I refuse to believe in this much convergence without hearing a good “just so” story. Would someone care to spin one !!!

  3. 3
    Johnnyfarmer says:

    Barb thanks for your comment. I have a special interest in instinctive or inherited unlearned behavior. I usually like to use birds for examples but this spider is perfect.

    The thought that genes cause behavior seems quite suspect… a gene associated with a particular behavior is more in line with my thinking. We know that instinctive behavior is often triggered by outside environmental changes which affect hormonal balances. But where is this information (which includes the knowledge for survival) hidden and how is it inherited. And one of my main objections is for Darwinists to assume that behavioral patterns are subject to mutations to the same degree as physical changes are !!! …. where is the evidence ???

  4. 4
    Johnnyfarmer says:

    Am I to believe in a simultaneous synchronized convergence of both physical and behavioral traits ???

    Well actually for unguided evolution to occur you sometimes need both a physical change along with a behavioral change working together to improve a function…. which would seem to involve a lot of luck to get that….

    In this specific case the improved function is to mimic the ant.

    Question: If a spider holds up two legs to appear as an ant …. would this be real convergence or only mimicking convergence??????????? …. since the legs are not actually antennas but only function to mimic antennas ?????

  5. 5
    goodusername says:

    Looking 5% like an ant is exactly what a spider needs for the perfect disguise during the critical first few generations!

    If an creature’s appearance fools its predators only occasionally, that’s better than nothing. And even the best disguise probably doesn’t work 100% of the time.

  6. 6
    Johnnyfarmer says:

    Its not at all typical for a spider to rely on just one insect food source so this spider would need to have evolved in a situation where he could only access ants for food. How improbable is that !!!!

    …. the “just so” story for this one it going to no doubt be a whopper !!!!!!!!!!!!

  7. 7
    Johnnyfarmer says:

    Well after some contemplating I have decided this is not an example of convergence. Convergence requires the independent evolving of same or similar characteristics. In this example the evolving of the spider is not independent of the ants evolving. The ants characteristics existed first and then any random ant-like mutations in the spider would be selected for. Selection would favor characteristics mimicking the ant.

    If the ant did evolve by an unguided process then it would be feasible that this spider could also have evolved… The big “if”

    …. the big “if”

    And as I suggested @ 3 …. How can science assume that inherited behaviors can vary and be selected for ?

    The answer is that science must assume, otherwise evolution could not proceed !!!

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