Moth defense against a Spider
Moths are covered in tiny scales. When the moth hits the web the tiny scales can shed off and allow the moth to break free (Brunetta and Craig, 2010). The moth may have developed this as a defense towards the spiders web over the thousands of years.
figure 1: The microscopic scales on a moths wings. (Irving, 2015)
However in my previous blog about the bolas spider, I said that the spider creates a globular blob which then sticks to the moth that flies into it. Therefore the moths scales would make little impact to help free itself. This technique of shedding scales could only work on a silk web. The moth gets hit by the bolas and when it tries to free itself it makes itself more tangled in the web (Brunetta and Craig, 2010).
A different possible defense to the bolas spider is that the bolas spider produces two pheromones to attract two different types of moth. Lacinipolia reginera is one of the moths and when it detects its pheromone it flies towards it, even if a different pheromone is being released from the area/ source too.
However a different species of moth from the same area Tetanolita mynesalis is attracted to its pheromone, however if a different pheromone is also being released such as the one for L.reginera, it flies away (Burchsted, 2015).This is one defense mechanism that the L.reginera has developed against the bolas spider.
Laniocera hypopyrra -Chick that mimics a caterpillar (answered questions)
One of the questions asked on the previous blog was if the chick was a similar size to the caterpillar.
According to the American naturalist journal the chick is 14cm in length, which is a very close size to the caterpillar, which is 12cm in length (Yirka, 2015) .
Another fascinating fact about this chick is that it acts like the caterpillar almost exactly. It make movements and doesn't call out until it receives a signal from its mother. Then it resumes to being like a chick (Yirka, 2015).
References
Brunetta, L. and Craig, C. (2010). Spider silk. New Haven: Yale University Press.
Burchsted, A. (2015). Bola Spiders Lure and Eat Moths. [online] Suite. Available at: https://suite.io/albert-burchsted/2pjn2a5 [Accessed 5 Apr. 2015].
Irving, R. (2015). Wing scales help camouflage from sonar: moth - AskNature. [online] Asknature.org. Available at: http://www.asknature.org/strategy/be92d2132e07f8a21d54f687a314a878#.VSEwSvnF-8A [Accessed 5 Apr. 2015].
Yirka, B. (2015). Amazonian bird chicks mimic poisonous caterpillar to avoid detection. [online] Phys.org. Available at: http://phys.org/news/2014-12-amazonian-bird-chicks-mimic-poisonous.html [Accessed 5 Apr. 2015].
I don’t understand something. You state that L. reginera will fly towards the odour cue, regardless of whether it resembles its own pheromone, whereas T. mynesalis flies away if the other pheromone is produced. How is this a defense mechanism then for L. reginera? It seems to me that flying towards the odour cue, even if it is not your own, is exactly the way to get caught!
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