Plants use various methods to avoid their predators. In today's case, we'll meet another example of aggressive mimicry in passionflower species. Heliconius butterfly larvae is the fiercer predator of passionflowers plants. Also, these insects lay their eggs on the leaves of passionflowers plants. However, they do not lay their eggs where has eggs from other Heliconius butterfly. So, that plant found a way to deceive these predators. Around 2¢ of passionflower plants have evolved pigment protuberances on the structure of the plant (Figure 1) that mimic Heliconius egg. So, the butterfly by-pass the plant because it saw structures that seems like eggs and they do not lay there. These structures are found on the stem and leaves.
Figure 1: Passionflowers plants with pigment protuberances
Curiosities:
Besides mimics, these plants use other mechanisms. An interesting mechanism is
found in Passiflora foetida (Figure 2). That
plant evolves an odour (smell) which fools butterflies onto believing that the
plant is unfit or rotting. As a result, the butterflies avoid them.
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Figure 2: Passiflora foetida
Reference
Scott, P. 2008, Physiology and Behaviour of plants, 1st edn, Wiley: USA
Figures viewed 04 May 2014:
Figure 1:http://commons.wikimedia.org/wiki/File:Foetid_passionflower_%28Passiflora_foetida%29_%286128013446%29.jpg
Figure 2: http://adarwinstudygroup.org/biology-culture-psychology/mimicry/
Very interesting. I’m curious as to what triggers the formation of these plant growths? Do older plants have a higher number of growths? If these plants produce a scent that resembles decay, does this mean that their main pollinators are flies or carrion beetles? How often will butterflies lay eggs, even when plants have growths? Fascinating topic!
ReplyDeleteSome scientists believe that when the plant is eaten so they send a message saying that something has to be changed. So, some process started to minimize the loss.
DeleteNot necessary older plants have more growths. It depends on the degree that the plant has been attacked. However, in general they have the same quantity of growths. Perhaps a young plant could have less because it is still in development.
I am not sure if the pollinators are flies or carrion beetles. Probably they are. Also, that plant is known as an almost carnivore plant. It is called “almost” because they do not completely digest the all animal, only some structures. Definitely, the rotten smell attract these insects to be eaten too.
that is so interesting! We can see here 3 cases of mimicry from the same family against the same kind of predators. I'm fascinated for this matter because it is like if these organisms could "think" and "have a great idea" to produce specific mimicry directed to avoid their predators. I'm wondering if these plants can have any costs to produce these mimicries. For example, maybe they could have some negative effects from energy expenditure for producing these mechanisms. Or even they had in the past. What do you think?
ReplyDeleteInteristing question Samiria! Yes, they have some energy cost to do that. Some scientists believe that when the specific mimicry had been created it was more costly but over the years the plants specialized in do that modifications and the costs have been diminished. Also, even though there is cost or negative effects the benefits are bigger.
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