We all know about having a favourite star, and wanting to look just like him or her. The hair, the clothes, the body, the look: we want it all. And why? Well, in evolutionary terms, we (the mimics) want the receiver (hot date?) to think that we are just like the model (take your pick). It’s an evolutionarily adaptive strategy to adopt the traits that do well in one’s species. Again drawing on the work of evolutionary theorists, it is believed that such traits allow us to thrive and succeed, and to reproduce, giving us our chance to pass on those great genes to our little ones. But what if (in our minds, anyway) we don’t really have great genes – what if we’re just mimicking those who do by looking, acting, or even smelling like them? Starts to give you the idea of why ads make use of super gorgeous, successful-seeming people, doesn’t it? Why else would we buy this perfume or that shirt if we weren’t inspired by the fantasy that they may somehow make us look like that model in the ads?
Well, let’s not feel too cheap and gullible: humans are not the only ones that like to be copycats. Nature provides many examples of organisms that have taken on some trait of another species so as to capitalize on the image the model (the original) has in the receiver’s (in many cases, predator’s) eyes. There are several types of mimicry, and organisms as diverse as insects, plants, birds and mammals make use of the benefits copying provides.
The most easily understood type of copying is known as Batesian mimicry. Named after the scientist who discovered the pattern, Batesian mimicry is characterized by a poorly-defended mimic looking like, behaving the same way as, or in some other way copying the traits of a well-defended model. In such a case, the mimic gains by the fact that predators know to avoid animals with the given traits. Examples of Batesian mimicry are numerous, but the trait is most commonly seen in insects. Defenseless flies and beetles can be found that are excellent replicas of stinging bees and wasps; tasty butterflies exist that are for all intents and purposes identical to poisonous model species. And insects are not the only ones to capitalize on predators’ dislike for unpalatable species. A whole mimicry ring exists around the highly poisonous coral snake: its bright warning colours are effective in deterring predation, making clear the reason that its colour patterns are mimicked by several other species of snakes.
Another type of mimicry is a little less intuitively adaptive. Mullerian mimicry is a form of copying in which both the mimic and the model are, in fact, unpalatable, or unpleasant to eat. There is less deception and trickery involved in this type of mimicry, and the mimics are not in this case just along for a free ride. Rather, species making use of this type of similarity between groups capitalize on the fact that the learning process of a predator will impact minimally on any one species, as individuals lost to a predator’s early education in palatability will be distributed among the mimicry groups.
Not all mimicry has to do with predator-prey relationships. In some of the most interesting cases, mimicry is about gaining entry into the secret society of other species. One example of such incursion into other species’ domains is that of the beetle which, disguised as an ant, is able to gain food, shelter and protection by fooling ant colony members into believing that it is the genuine article, worthy of full entry into the colony. Other animals that make use of such sneaky tactics are the cowbird and the cuckoo. The epitome of what some may call a lazy parent, the female of these species lays her eggs in the nests of other birds – birds which lay nearly identical-looking eggs to her own. The parents of the latter species end up doing the incubating and raising work of the cowbird or the cuckoo, leaving these lucky moms with a painless child-rearing experience. In the world of conservation biology, the use of such a strategy is known as nest parasitism, and has been found to have important negative effects on the host species. If the parasite species’ eggs and young are larger than those of the host, the host parents may abandon the smaller of the clutch (in reality, their own young) in favour of raising what seem to be the healthier, more robust of their nest occupants. Such are some of the downsides of mimicry.
Interestingly enough, plants can also factor into the mimicry equation. Some species, such as certain nutrient-deficient bog plants, mimic the odour of rotting carrion to entice hungry insects. Once lured close enough to the plant’s opening, the hapless insects will find themselves sliding down the slippery slope of the plant’s digestive system, right on into its stomach. The plant gets a nutrient-rich meal and, unfortunately for the fly, serves to demonstrate quite nicely the adaptive benefits of mimicry. Such tactics are aptly termed aggressive mimicry.
But not all plant-related mimicry is so ill-intentioned. On the contrary, many plants lure butterflies or other insects to them not for culinary purposes, but rather to aid in reproduction. By mimicking salient traits of a pollinator’s mate, for example, a plant can lure to its pollen-producing parts a mate-searching insect, and thus take advantage of the insect’s pollen collection, dispersal and distribution services. To keep the pollinator coming back, the plant usually provides the insect with a tasty treat of some sort.
Finally, the tables can be turned in the plant-insect relationship. Some insects have evolved so as to mimic the traits of important plants in their habitat. Stick insects are a prime example, and have developed to such a degree that they are almost invisible when on their host plants. But appearance is not the only way in which animals such as these mimic plants. Certain animals, such as stick insects and grass snakes, have developed the behavioural trait of swaying so as to mimic the movement of plants in their habitat, and fool predators into believing that their movement is nothing more than that of a plant’s waving on a windy day. Of course, such mimicking patterns are more commonly referred to as camouflage, and camouflage techniques are not confined to prey species. The coat patterns or movement strategies of many predator species help them to blend into, be camouflaged by, or, in other words, to mimic their surroundings.
There, then: as we sit around at this time of year in our bathing suits, closing our eyes and picturing the body below our heads to be just like that model’s on TV, we can rest assured that we are not alone in the natural world in trying to capitalize on other’s good features. Mimicry is everywhere, and while it is not always the most honest way to go, we’ve seen here that it certainly can be useful!
Check out any good biology text for an introduction to mimicry, its variations, and its evolutionary significance. Specific examples are easy to find by just typing “mimicry” into a search engine. It’s worth looking around for pictures: these copycats can be not only deceiving, but downright impossible to distinguish from the real thing:
Zoe Dalton is a graduate of York University’s environmental science program, and is currently enjoying working towards a Master of Arts in Integrated Studies with Athabasca U. She can be reached for comments or questions at firstname.lastname@example.org.