Table of Contents
What is mimicry in plants?
Mimicry can be defined as a behavioral adaptation whereby a living organism evolves to resemble or look like another organism or object; they usually do this to help them live longer and survive predation. This is an effective adaptation in animals as well as in plants. Mimicry in plants is very useful for the survival of the plants against herbivores and also helps in aiding pollination.
Definition
Mimicry in plants is the development of a plant to resemble another organism either physically or chemically. There are fewer documented cases and peer-reviewed studies of mimicry in plants than in animals. It has been studied far less than mimicry in animals.
However, in plants, mimicry gives protection against herbivores. Also, in plants it may deceptively encourage mutualists, such as pollinators, to render service without offering any reward to them.
Types of mimicry in plants
- Bakerian mimicry: This is a type of mimicry in plants, whereby the female flowers imitate males of the same species.
- Mullerian mimicry: This is a type of mimicry whereby a plant mimics a rewarding flower.
- Dodsonian mimicry: This is a form of mimicry in plants that mimic another species of fruit or flower to lure pollinators. The feeders of the other species are attracted to a fake fruit to distribute seeds.
- Vavilovian mimicry: This involves a mimicry that a weed that is unintentionally artificially selected to resemble a crop plant.
- Pouyannian mimicry: This mimicry involves a flower mimicking a female mate for a pollinating insect.
- Batesian mimicry: This is a form of mimicry whereby a harmless species mimics characteristics of a harmful species to deter predators.
- Leaf mimicry: This mimicry involves a plant mimicking a nearby plant in order to evade the attention of herbivores.
- Pseudocopulation: This is a form of mimicry that occurs when a flower mimics a female of a certain insect species. Thus, inducing the males to try to copulate with the flower
- Cryptic mimicry: This is a type of mimicry whereby an organism provides false signals or a lack of signals in order to deceive a potential predator
Bakerian Mimicry
This is a type of mimicry in plants, whereby the female flowers imitate males of the same species. It was named after Herbert G. Baker and is a form of intraspecific mimicry or automimicry. In this mimicry, the female flowers mimic male flowers of their own species. Thereby, cheating pollinators out of a reward. Bakerian mimicry is common in many species of Caricaceae. Caricaceae is a family of angiospermous plants that belong to the order Brassicales. They are found mainly in Africa and tropical regions of Central and South America.
Dodsonian mimicry
This is a form of mimicry in plants that mimic another species of fruit or flower to lure pollinators. The feeders of the other species are attracted to a fake fruit to distribute seeds. It was named after American botanist and taxonomist, Calaway H. Dodson
Similar to Bakerian mimicry, the Dodsonian mimicry is a form of reproductive floral mimicry. However, in this case, the model is of a different species than the mimic. The plant gives sensory signals similar to the model flower and lures its pollinators. These plants provide no nectar for the pollinators.
Typical examples include Epidendrum ibaguense, a species of epiphytic orchid of the genus Epidendrum. Epidendrum ibaguense mimics flowers of Lantana camara and Asclepias curassavica. It is pollinated by monarch butterflies and perhaps hummingbirds. These mimics occur in Trinidad, Colombia, French Guiana, Venezuela, and northern Brazil.
Vavilovian mimicry
This involves a mimicry of a weed that is unintentionally artificially selected to resemble a crop plant. Vavilovian mimicry is seen in weeds that share features through artificial selection with a domesticated plant. This mimicry was named after the Russian botanist and geneticist Nikolai Vavilov. Selection against the weed can happen either by using winnowing to separate its seeds from those of the crop or by manually killing the weed.
Vavilovian mimicry is a defensive mimicry as the weed mimics a protected species. This has a strong similarity to Batesian mimicry. This is because the weed does not share the characteristics that give the model its protection. However, there are some key differences between Batesian mimicry and vavilovian mimicry. The model and dupe are enemies in Batesian mimicry, whereas in vavilovian mimicry, the crop and its human growers are in a mutualistic relationship. Despite being eaten by humans, the crop benefits from being dispersed and protected by humans.
The actual reason the crop is protected is as a result of its usefulness to humans. Additionally, the weed crop is destroyed and not eaten. In fact, the only reason for killing the weed is because it affects the crop yields. Finally, it is important to know that this type of mimicry does not occur in ecosystems that are not altered by humans.
For example, in rice fields, the early barnyard grass is a weed that looks similar to rice. The seed of the weed is usually mixed in rice and has become difficult to separate as a result of Vavilovian mimicry. Vavilovian mimics eventually may become domesticated themselves like in the case of rye in wheat. Nikolai Vavilov called these weed-crops secondary crops.
Pouyannian mimicry or Pseudocopulation
This is a form of mimicry that occurs when a flower mimics a female of a certain insect species. Thus, inducing the males to try to copulate with the flower. This form of mimicry in plants is much like the aggressive mimicry in fireflies as discussed previously. However, there is a more harmless outcome for the pollinator as compared to the aggressive mimicry in fireflies. This form of mimicry is called pseudocopulation and has also been called Pouyannian mimicry named after Maurice-Alexandre Pouyanne. He was the first to describe the phenomenon.
This mimicry involves a flower mimicking a female mate for a pollinating insect. Several plants have evolved to look like other organisms, especially insects. This can be of benefit as well as increase pollination. In this mimicry, the flowers mimic a potential female mate visually. However, the key stimuli are usually chemical and tactile.
For example, the hammer orchid has both visual and olfactory mimics of a female wasp. The mimicry lures males to deposit and pick up pollen. Hammer orchid is native to Australia and is an endangered genus of orchid. Pouyannian mimicry is most common in orchids. The orchids mimic females of bees and wasps accounting for around 60% of pollinations. A pollen sac called pollinia, depending on the morphology of the flower is attached to the abdomen or head of the male. The pollen sac is then transferred to the stigma of the next flower that the male tries to inseminate. Hence, resulting in pollination.
Also, physiologically and morphologically, the orchid Epipactis helleborine is adapted to attract social wasps as their primary pollinators. These social wasps feed their larvae with insects such as caterpillars. However, to locate their caterpillar prey, they make use of a combination of olfactory and visual cues. The flowers of Epipactis helleborine and Epipactis purpurata releases green-leaf volatiles (GLVs). These emitted volatile are attractive to foragers of the social wasps (Vespula germanica and V. vulgaris).
Batesian mimicry
This is a form of mimicry whereby a harmless species mimics characteristics of a harmful species to deter predators. It was named after the English naturalist Henry Walter Bates. In this mimicry, a harmless organism evolves to imitate the warning signals of a harmful organism which is directed at a predator that preys on both organisms.
Thorn mimicry is an example of Batesian mimicry. Two types of thorn mimicry have been seen in plants.
- The first type of thorn mimicry is a special case of intra-organismic Batesian mimicry. It is seen in Aloe vera, Liliaceae, W. filifera (Palmaceae), and dozens of species of Agave, such as Agave applanta, Agave obscura, and Agave salmiana. On the face of their leaves, they develop thorn-like imprints or colorations. This is as a result of the teeth along the margins of that leaf or another leaf pressing sustained indentations into the flesh of the non-spiny parts.
- The second type of thorn mimicry is a more classic case of Batesian mimicry. It involves the pointed colorful organs of memetic plant species such as the buds, leaves, and fruit that mimic aposematic colorful thorns that are not found anywhere other than the organism.
There are many plants that grow in Greece, Israel, Estonia, and Japan that exhibit possible spider web mimicry. In a case of visual mimicry or perceptual exploitation, on newly extended stems and leaves, dense white trichomes are produced that deter herbivory as a result of predatory habit or toxicity. Such case examples are the new fronds of Osmunda japonica from Japan, new buds of Onopordum from Israel, flower heads of Arctium tomentosum from Estonia, Carthamus sp. from Greece, a fledgling leaf of Tussilago farfara from Estonia.
Cryptic mimicry
This is a type of mimicry whereby an organism provides false signals or a lack of signals in order to deceive a potential predator. Crypsis in ecology is the ability of an organism to avoid detection by other organisms. Cryptic mimicry occurs in plants. Moreso, it is usually achieved visually.
For example, the climbing vine, Boquila trifoliata is a South American member of the family Lardizabalaceae. It has a highly variable phenotype. This plant is capable of mimicking the leaf features of plant species that it clings to. It adopts the color shape and size of the leaves. Therefore, Boquila lowers its chances of herbivory by camouflaging its leafy appendages.