Does the presence of the black and yellow eye-spot rings on the wings of male and female Saturnia Pavonia intimidate the predators and deflect the attacks and contribute to their higher survival rate?
Introduction
Saturnia Pavonia is a Lepidoptera insect from the family of Saturniidae which is habituated in the moorland and heathers. The Saturnia Pavonia have several distinctive features that can serve as an adaptation in these successful and widespread moths. The wingspan of the male moths is smaller than females by 10mm and are both covered with long hairs on their thorax.
The males have mostly 4 eyespots on their wings, 2 on the front wings which are black and yellow, similar to the eyes of an owl, on the background of dark brown on the front wings and orange on the rear wings. However, females have a grey and light brown coloration and have the same eyespot patterns as the males. The antennas in males are used to detect pheromones, the antenna in the males are much larger than females,in order to detect the scent of females (the pheromones) released by the female’s abdomen glands. Saturnia pavonia have been adapted to its environment and developed ways to be selected. One of the adaptive characteristics in moths is camouflaging and Mimicking by the moth’s wings eyespots and pattern. Based on the data gained from Cambridge university press It is known that several kinds of mimicry strategies in moths are more common such as crypsis which is having certain wing pattern and coloration in order to blend in to the environment, mimicking other poisonous moth species and having eyespots that either scares the predators off or resemble a certain feature of their environment like a tree ring or spots on leaves or flowers . Based on the experiment done by NCBI on the effect of the eyespot patterns on moths fitness , Lepidoptera moths were injected with heparin which led to shiny stings on the black spots on the moths from different genus and increased fitness and survival when they were exposed to predators, their ability to camouflage and hiding from the predators were increased compared to moths without eyespots.(Sourakov 2017)
The most prominent trait in the Saturnia pavonia moth is the 4 eyespots on the front and hind wings. Based on Natural selection theory of evolution and adaptation, the gene representing the presence of the black eyespots were favored in the moths and had a higher frequency using gel electrophoresis method. it had been chosen by the natural selection. this results into higher fitness of moths with black and yellow eyespot and had been represented over generations by natural selection. ( Neudecker 1989)
As this coloration and eyespot patterns can increase the survival of the moths, natural selection will favor its presence. The predator-prey interactions are one the most important forces which is affected by natural section. There are several ways that help prey not to either be detected or be consumed. The first step of anti-predator strategy is detection. Several methods such as camouflaging and mimicry helps the preys to survive. (Stevens,2005)
As stated above some of the saturnian pavonia moths have different numbers of rings eyespots which comprises 4 circular shaper eyespots on the frontal wings.In this proposal I would like to investigate whether the presence of black and yellow eyespots rings on the wings of male and female Saturnia Pavonia has an effect on their survival rate by deflecting and intimidating the predator(other than owl)
Methods
In order to test the hypothesis on the effects of the eyespots on the fitness of the saturnian moths a proper experiment is needed. The purpose of this experiment is to measure the number of the sturnia moths that survived from the predator’s attacks with different number of eyespots on their wings. The independent variable is the presence of eyespots on the male and female saturnia and the dependent variable is the number of survived moths after being encountered with the predator Lacerta vivipara which are abundant in the heather and moorlands. I excluded predators such as owl as the eyespots may be a resemblance of owl eyes which is more familiar to the owls themselves than lizards and other spices which makes this experiment more valid and can be studied in a separate experiment.
The condition of the experiment is controlled by using food sources such as Calluna vulgaris and Eriophorum angustifolium (common cottongrass) as the plants common in the heathers and moorlands and the main source of food for these moths. The temperature in this experiment used is 30degres which is the median temperature in the moorlands and during the time when the moths are more active. the temperature will remain constant in order to avoid any construct and they are housed in a glass terraria with (100x80x120)and is equipped with cotton grasses. The method that I am using for hiding eyespots on the wings is by printing patterns of background pattern of the wings of both male and female, on the thin papers by 3D laser printers and sticking them on their wings by special glues. The reason why I used thin papers is to eliminate the effect of any additional weight on the wings ( Sourakov ,2017)
The experimental groups are divided into 2 groups of moths with 4 normal eyespots on the wings of both male and female (Group1), moths with no eyespots covered by tissue papers with the background pattern of the moths (Control group) .At first, I am going to use the group 1 and the control group to check whether the printed eyespots don’t have any effect on moth’s normal function. Then we are going to expose these three moths in their different experimental space with the lizard(predator). The result of the experiment will be checked within 2 days.
Predictions
There are 3 different outcomes in this experiment. First is when the number of survivors are significantly higher in moths with 4 eyespots. second when the plain moths(Control group) were more successful in surviving and third when both grouped had the same survival rates. The Null hypothesis in this experiment is that the increased number of eyespots don’t have any effect on their survival. If the number of the survivors and preyed moths was not equal the null hypothesis is rejected and there has been an effect of the eyespots on survival rate.
If the number of the survivors was equal to the number of attacked moths my null hypothesis is not rejected and there is no significant effect of presence of eyespots on their fitness. The control group makes sure that the results are not based on other factors.
Discussion
The experiment indirectly checks the camouflaging effect on the fitness of saturnian pavonia.
If the null hypothesis is rejected, th presence of the eyespots on the wings of saturnian pavonia male and females resulted in higher survival rate, meaning that these eyespots are mimicking and acting as a camouflaging effect and can increase the fitness of the individuals. And the absensence of the eyespots on the wings results in fewer number of survivors and less fitness.
If the experiment result does not reject the null hypothesis it means that the presence of the eyespots has nothing to do with the survival of the individual or it would have the opposite effect on their survival rate.
And this species might have this trait as a result of sexual selection acting on the individual to increase its reproductivity ability or can be as a result of the biological byproduct.
Literature cited
Sourakov A. Giving eyespots a shiner: Pharmacologic manipulation of the Io moth wing pattern. F1000Research. 2017;6:1319. doi:10.12688/f1000research.12258.2.
Stevens, M. 2005. The role of eyespots as anti-predator mechanisms, principally demonstrated in the Lepidoptera. Biological Reviews, 80(4), 573-588.
Polunin, Oleg; Walters, Martin (1985). A Guide to the Vegetation of Britain and Europe. Oxford University Press. p. 220. ISBN 0-19-217713-3.