When a plant mimics another.

Figure 1. Watsonia densiflora
Photo by: H. Booysen

This is the Watsonia densiflora (Figure 1). This flowering plant can be found in open grasslands of KwaZulu-Natal and the Pondoland region, in South Africa. The flowers of this plant attract pollinators with its nectar, rewarding with food any insects that will land on it (Johnson & Morita, 2006).

Particularly, this plant attracts a certain species of fly, the Philoliche aethiopica (Figure 2), as a pollinator (Johnson & Morita, 2006). Because of its long proboscis tabanid (a long, tubular mouth part), this fly is well adapted to feed on floral nectar and reach the bottom of their tube, and will be able to spread its pollen from a plant to another (Karolyi, Colville, Handschuh, Metscher & Krenn, 2014) 

Figure 2. Philoliche aethiopica foraging on a
Watsonia densiflora
Photo by: M. Whitehead.

But this insect as also been observed pollinating and favouring another similar plant: the flowering plant Disa nervosa (Johnson & Morita, 2006)

Figure 3. Disa nervosa
Photo by: R. Boon

And this is not a coincidence. In fact, the Disa nervosa (Figure 3) is a liar. This plant has a similar distribution to Watsonia densiflora, and its flowers look very alike to Watsonia's flowers in both dimensions and colours. The only difference is that the Disa nervosa doesn't produce any reward for its pollinators. But due to this high ressemblance and common distribution they share the same pollinators, as the Philoliche aethiopica cannot differ between those two plants. While this fly thinks it will land on a Watsonia densiflora and will beneficiate of its nectar as nutrients, it might actually land on a Disa nervosa by visual mistake and won't be able to collect any nectar, but will still be covered by its pollen and will spread it on another flower (Johnson & Morita, 2006)

According to Johnson and Morita's research (2006), this technic of pollination by mimicry is quite effective in some sites, as it has been found that 50% of Disa nervosa's flowers has received or exported pollen.

Reference list

Boon, R. (2015). Disa nervosa [Image]. Retrieved from http://www.ispotnature.org/node/644187

Booysen, H. (n.d.) Watsonia densiflora [Image]. Retrieved from https://midlandsconservanciesforum.wordpress.com/2015/02/11/dargle-wildlife-sightings-january-2015/

Johnson, S. D. & Morita, S. (2006). Lying to Pinocchio: floral deception in an orchid pollinated by long-proboscid flies. Botanical Journal, 152(3), 271-278.

Karolyi, F. Colville, J. F. Handschuh, S. Metscher, B. D. Krenn, H. W. (2014). One proboscis, two tasks: Adaptations to blood-feeding and nectar-extracting in long-proboscid horse flies (Tabanidae, Philoliche). Arthropod Structure and Development, 43(5), 403-413.

Whitehead, M. (2013) Philoliche aethiopa foraging on a Watsonia densiflora [Image]. Retrieved from https://michaelrwhitehead.wordpress.com/2013/01/

The Caladium steudneriifoli, a plant that pretends to be sick all day every day.

Everyone has pretended at least once in their life to be ill, to avoid school, work or going out on a rainy day. Well, today I will talk to you about the Caladium steudneriifolium, a plant that pretends to be ill every day. This plant is found in the rainforest of Colombia, Peru and Ecuador, where it regularly gets consumed and attacked by mining moth caterpillars (Soltau, Dötterl, Liede-Schumann, 2009). To avoid being eaten, the plant will produce irregular white patches on top of its leaves, called variegation, that are similar to the one left after being consumed by a caterpillar (Figure 1) (Soltau, Dötterl, Liede-Schumann, 2009). This mimicry will protect the plant, as the female moth will believe that another larvae has already consumed a part of the leaf. Therefore, the insect will assume that it does not contain enough resources for its offspring anymore, and will avoid laying its eggs on the ill looking leaves (Soltau, Dötterl & Liede-Schumann, 2009).

A research by Soltau, Dötterl & Liede-Schumann (2009) has found that leaves showing variegation patterns are 4 to 12 times less damaged than the other plain green leaves.

 So, yes…

IT WORKS!

Figure 1. Left photo: A leaf of a Caladium steudneriifolium, damaged by a
mining moth caterpillar
Right photo: A leaf of a Caladium steudneriifolium mimicking the damage
by a mining moth caterpillar.
Photo by: M. Walker.

Reference list:

Soltau, U. Dötterl, S. & Liede-Schumann, S. (2009). Leaf variegation in Caladium steudneriifolium (Araceae): a case of mimicry? Evolutionary Ecology, 23, 503-512.

Walker, M. (n.d.).Left photo: A leaf damaged by a mining moth caterpillar, Right photo: A leaf mimicking the damage by a mining moth caterpillar [Image]. Retrieved from: http://news.bbc.co.uk/earth/hi/earth_news/newsid_8108000/8108940.stm

The relationship between the Passion Flower (Passiflora) and the Zebra longwing butterfly (Heliconius chaithonia)

Figure 1. Photo of a Zebra longwing
 butterfly (Heliconius charithonia)
Photo by: C. Quigley.

The zebra longwing butterfly (Heliconius charithonia) (Figure 1) is a species of butterfly that uses the leaves of the Passion flower (Passiflora) plants to feed its larvae (figure 2) (Williams & Gilbert, 1981). To do so, the butterfly will lay its eggs directly on the leaves of the plant, and when the eggs will hatch they will simply feed on them (Williams & Gilbert, 1981). So obviously this is a great way for the butterfly to ensure the surviving of its offspring, but on the other hand the plant loses a part of its leaves each time an egg hatches. 

Figure 2. Photo of two larvae of the
 Zebra longwing butterfly (Heliconius
 charithonia), feeding on the Passion
 flower (Passiflora) leaves.
Photo by: H. Nendick-Mason.

Figure 3. Photo of the Passion Flower
(Passiflora) leaves imitating the Zebra
 long wing (Heliconius charithinia)
butterfly eggs.
Photo by: G. Dimijan & M. B. Dimijan.

This competition between the Passion flower plant and the longwing butterfly has pushed the plant to evolve and develop an effective defense mechanism. The passion flower will indeed mimic eggs on the top of its leaves so the butterfly will automatically think that the leaves have already been used by another butterfly for its young. Therefore, it will look for another available plant to make sure there will be enough available resources for its offspring (Williams & Gilbert, 1981). According to Williams & Gilbert (1981) this mimicry significantly decreases the number of eggs on the leaves and consequently reduces the herbivory by the larvae.

Reference list

Dimijan, G. & Dimijan, M. B. (n.d.).  Passion Flower (Passiflora) leaves imitating the butterfly eggs [Image]. Retrieved from: http://adarwinstudygroup.org/biology-culture-psychology/mimicry/

Nendick-Mason, H. (n.d.). Photo of 2 larvae of the Zebra longwing butterfly (Heliconius charithonia), feeding on the Passion flower (Passiflora)[Image]. Retrieved from: http://www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/zebra_longwing.shtml

Quigley, C. (n.d.). Photo of a Zebra longwing butterfly (Heliconius charithonia) [Image]. Retrieved from: http://my.chicagobotanic.org/events/zebra-longwing-the-friendliest-butterfly-around/

Williams, K. S. & Gilbert, L. E. (1981). Insects as Selective Agents on Plant Vegetative Morphology: Egg Mimicry Reduces Egg Laying by Butterflies. Science, 212(4493), 467-469.

The Bee Orchid (Ophrys apifera), this cheeky little plant.

Figure 1. Photo of a group of Bee Orchids (Ophrys apifera), mimicking
female bees.
Photographer: D. James.

So now that I have gotten you all excited about the idea of discovering incredible cases of plant mimicry, I would like to talk to you about one of my favorite examples; the Bee Orchid (Ophrys apifera). As I have already mentioned in my previous post, this plant uses its flowers to imitate the targeted pollinators (Figure 1). As male bees fly pass the orchids, they will think that the flower is a potential mating partner (Vereecken & Geroud, 2007). In addition to physically imitating the female bee, the plant also produces a smell that is similar to that of a female bee which strongly attracts the males. As a result, the males will try to mate with the plant... Unsuccessfully (Vereecken & Geroud, 2007). This video perfectly displays the disappointment felt by the bee:

Unfortunately, it is not the end of the bee's disappointment... Indeed, the flower does not provide any reward to the insect, such as nectar or consumable pollen, like most of the plants (Vereecken & Geroud, 2007). But on the other hand, the plant is perfectly satisfied as the male bee is now covered by its pollen. This pollen will be transferred to another Bee Orchid when it tries to copulate with another flower (Johnson & Kindlmann, 2006).

And this is how they reproduce!

Sadly, even if it seems like an incredibly smart way of pollination, it doesn't work as much as it should, with only about 15% of plants successfully reproduce per year (Vereecken & Geroud, 2007).

Reference list:

James, D. (n.d.). Photo of a group of Bee Orchids (Ophrys apifera), mimicking female bees [Image]. Retrieved from http://www.davidjameswildlifediary.com/2014_06_01_archive.html
Johnson, S. D. & Kindlmann, P. (2006). Mechanisms and evolution of deceptive pollination in orchids. Biological Reviews, 81(2), 219-235.

• Vereecken, N. & Genoud, D. (2007). La pollinisation de l’Ophrys arachnitiformis (Orchidaceae) par les mâles de Colletes cunicularius (L.) (Hymenoptera, Colletidae) dans les Pyrénées-Atlantiques (France). Osmia, 1, 20 -22.

Plant mimicry, its evolutionary advantage.

Figure 1,  The bee orchid (Ophrys apifera)
improves its pollination by mimicking
a member of its targeted pollinators.
Photographer: N. Cotner.

  According to Oxford dictionary of English (2005), mimicry is the "close external ressemblance of an animal or a plant, to another animal, plant or inanimate object". As we will cover a few examples on this blog, you will discover that some mimicry evolution has given birth to a lot of original and smart shapes. Also, some mimicry turn out to be pretty and interesting. But really, what purpose do they serve?

Figure 2, A group of living stones
(Lithops helmutii), surrounded by smaller 
rocks, easily hides from its predators.
Photographer: J. Hairan.

  Well, some mimicry will attract, whereas others will repel: for example, Figure 1 is not a photo of a bee, but rather a plant, known as a bee orchid (Ophrys apifera). The flowers of this plant have evolved to attract bees to facilitate the process of pollination (Vereecken & Genoud, 2007). Another example are the lithops, or more commonly known as "living stones", as seen in Figure 2. The big, rounded, and grey/pinkish part are all plants, which are surrounded by smaller rocks. This mimicry allows them to hide from their predators as they will consider that they are all rocks (Barrett, 1987), and there is no point eating rocks, right?

Even if this has only covered a small sample of plant mimicry topic, I am sure you have already understood that plants mimicry have evolved to give lots of useful survival advantages to plants. Wether it be the facilitation of reproduction by attracting pollinators, or even hiding in plant sight, plant mimicry ensures the continuity of their species.

Reference list:

Cotner, N. (n.d.). The bee orchid (Ophrys apifera) improves its pollination by mimicking a member of its targeted pollinators [Image]. Retrieved from http://www.fs.fed.us/wildflowers/pollinators/Plant_Strategies/mimicry.shtml

• Hairan, J. (n.d.). A group of living stones (Lithops helmutii), surrounded by smaller rocks, easily hides from its predators [Image]. Retrieved from http://www.cactuspro.com/conophytum-lithops/encyclopedie/lithops/helmutii/lithops-helmuthii.jpg.php
• Mimicry. (2015). In Oxford Dictionary of English. Retrieved from http://www.oxforddictionaries.com/spellcheck/words/?q=mimicry
• Barrett , S.C.H. (1987). Mimicry in Plants. Scientific American, 255(9), 76-83.
• Vereecken, N. & Genoud, D. (2007). La pollinisation de l’Ophrys arachnitiformis (Orchidaceae) par les mâles de Colletes cunicularius (L.) (Hymenoptera, Colletidae) dans les Pyrénées-Atlantiques (France). Osmia, 1, 20 -22.