Spider Evolution: Arachnid Can Mimic Ants Accurately to Avoid Predators

(Photo : Wikimedia Commons/François Bianco)
Spider Evolution: Arachnid Can Mimic Ants Accurately To Avoid Predators

Spiders have evolved and become wiser over time. The arachnids can surprisingly mimic ants for survival.

Spiders Can Mimic Ants

The process by which organisms change to resemble one another is called mimicry. An organism may benefit from this if the object it is mimicking is frightful or toxic, as this will deter predators from consuming it.

Being an ant is advantageous since ants, in particular, tend to be aggressive, taste bad, and attack in numbers. This is what many insects do because they have evolved to look like ants.

However, it was initially thought that because of evolutionary limitations, spiders were less able to mimic ants than other insects that were more closely related to ants. A new study proved this otherwise.

"We expected that ant-mimicking spiders would be more likely to experience constraints on body shape mimicry compared with ant-mimicking insects because of their considerable phylogenetic and morphological distance from the model. However, our results do not support this expectation," the authors of the study titled "Morphological ant mimics: constrained to imperfection?" "The most accurate spider mimics are almost as good as the most accurate insect mimics, both dorsally and laterally."

Therefore, the researchers found that imperfect imitation by insects or spiders is not the result of evolutionary restrictions. If natural selection exerts enough pressure, the limitations may be overcome.

They did discover that because of their excessive length and longer tails than other insects, spiders performed worse than other insects at laterally imitating ants. This, though, might be the result of the lack of pressure on them to resemble ants precisely in this dimension.

There may not be much selection for correct lateral mimicry, as evidenced by the lengthy tail of inaccurate spider mimics in the distribution. The fundamental disparities in body shape between spiders and insects (two stocky bodies) will be lessened if there is less selection for mimicry from a lateral aspect of spiders and insects. This is reportedly the reason why spider's body shapes are less ant-like.

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What Is Mimicry?

Mimicry is an occurrence in biology defined by the outward similarities between two or more taxonomically unrelated animals. Giving one or both of the species an advantage-like defense against this similarity allows the organisms to trick the living agent of natural selection.

The agent of selection interacts directly with similar creatures and is tricked by their similarity. Depending on the type of mimicry experienced, this agent of selection may be a predator, a symbiont, or the host of a parasite.

This particular kind of natural selection sets mimicry apart from other forms of convergent likeness that arise from unrelated creatures being subjected to other natural selection factors like temperature and dietary preferences.

The advantage is one-sided in the most researched mimetic relationships, where one species (the mimic) benefits from a likeness to the other (the model). Numerous plants and animals have been proven to be mimetic since the mid-19th century when mimicry in butterflies was first discovered.

Aside from mimicry, some animals camouflage with their surroundings to survive. One example is the great potoos. They are difficult to spot because they camouflage with the stump when they perched on trees. This gives them an advantage as it makes them undetected when they look for food. Giant flying insects mostly make up their diet.