Camouflage, in other words the ability to blend in with the surroundings is a profoundly studied feature in many animals. From empirical evidence, animals like Chameleon and the Leaf-Tailed Gecko which have pigments that match their surroundings are much harder to spot than animals whose pigments don’t. Recent studies have shown that the bark-resting moth has a tendency to live within a habitat that has a hue similar to itself. It can alter its position on the background for a better camouflage to avoid predation (Marshall 2016).
My test species the Phrynosoma Hernandesi, is an animal that is relatively a small and slow, making it an easy target for predation. Due their physical nature, P. Hernandesi relies heavily on camouflage to survive (James 2007). Thus hue similarity between the P. Hernandesi and its habitat will increase its chances of survival as predators can’t easily distinguish background and its prey. Studies have also shown that natural selection of animals within a specific environment can influenced their coloration in aid to their survival (Marshall 2015).
However, relatively few studies have shown the distinctive increase of rate on how camouflage help animals avoid predation within their environment. To my knowledge the essay Bugs with a backpack (Brandt and Mahsberg 2001) provided much insight to my question. It elucidates the effects of the disguises that West African assassin bugs use for survival. The study found that the survival rate of assassin bugs dramatically increased while donning a debris backpack when compared wearing nothing.
However this study does not directly reveal the correlation between camouflage and survival rate, since the backpack of assassin bug behaved like a protective shield than a camouflage (Brandt and Mahsberg 2001). Methods In Canada the P. Hernandesi are mainly found in southern Alberta and Saskatchewan, places where there are low human disturbance (James 2007). Their habitats are on slopes with little vegetation and loose soil to protect themselves from climate change and predation (James 2007).
I will conduct a field research in the Grasslands National Park, Saskatchewan during the active courting seasons of mid to late May. From this experiment I can test the hypotheses of how substantially the adaptive trait of camouflage aid lizards for survival (Brandt and Mahsberg 2001). The test samples will be of lizards P. Hernandesi, with sizes around the average of 52 to 69mm (James 2007). The control variable for the experiment will be set for the lizards of their original coloration of skin.
The independent variable lizards will be colour coated with the pigments that is lighter and darker than the original coloration. The pigments will be of non toxic powder colour mixed with water to create a rough texture similar to the skin of P. Hernandesi (James 2007). The pigmentation will not completely cover the scales of the lizard, in order to make the lizard still identifiable for the predators. I chose 2 predators to test with. The first predator is the Gartner snake Thamnophis elegans, which are known to have preyed on 3 lizards in earlier field studies (James 1997).
The second predator is ground squirrel Spermophilus richarsonii (James 2007). I will also starve the predators of food for 3 days to maintain their intensity to hunt (Brandt and Mahsberg 2001). The experiments will take place in the day time, in a circumscribed square arena of plastic wall around 5 x 5 meters of the grassland will be used as the experiment base of the predators (Brandt and Mahsberg 2001). We will then place the predators 5 hours before the experiment for them to adapt to the unfamiliar environment (Brandt and Mahsberg 2001).
The dependent variable we are measuring is the time it takes the predators to identify and attack lizards. The experiment will begin by placing the control lizards in the arena along with the Gartner snake and starting the timer. In order to be close to a natural study, I will place wireless recording cameras on the predator and stay far from the arena and view the predators movements through a screen. The trial will stop the moment the predator attacks the lizard. The control lizard will be taken out for pigmented lizard, and the pigmented lizard will be placed in the arena where the predator cant see.
After the first predator attacking the 3 types of lizards, the exact procedure will be experimented for the second predator. Through these experiments, we are able to measure how effective camouflage is for the survival of the lizard through the time trials. Predictions The value of this experiment is to determine whether P. Hernandesi’s pigment similarity with its habitat will increase its chances of survival. The null hypotheses is the similar coloration between P. Hernandesi and its habitat have no effect on their chance of survival.
In order for the null hypothesis to be accepted my experimental data must not show any relation between the time of predation for the different pigmented lizards. An example would be that the predation time for the controlled lizard is the same as the lizards with altered pigments or if the predation time for the controlled lizard is higher than any other time of the pigmented lizards. For the null hypothesis to be rejected, there must be a correlation between the pigmentation of lizards and the predation time.
The controlled group of lizards must take the longest time to be attacked due to their camouflage with the environment around while the pigmented lizards takes less time(Kjernsmo and Merilaita 2012). Discussion If the null hypothesis were to be rejected, it would mean from an evolutionary standpoint that the adaption of camouflage increases the fitness of the animal by lowering its rate of being preyed. As the prey is camouflaged the predators would take longer to locate its prey, so the prey can escape from predation (Marshall 2016).
If the results did not reject the null hypothesis, then it means that the similar hue of the lizard with its environment has no relation towards its vitality in terms of lowering the rate of being preyed on. But other assumptions could then be made that the trait of camouflage has other usages such as mating rather than to avoid predation. For example female lizards could be naturally inclined to find male lizards that have similar coloration to their environments, believing it is a trait of fitness.
