When competing within the same species it is known as intraspecific competition and when more than one species is competing with each other it is known as interspecific competition. This experiment utilizes two species of mealworms, Tenebrio molitor and Zophobas morio, to compete with each other and within their own species for food resources. Mealworms use grains, such as wheat bran, to provide a food source, a place to live and reproduce (Martin et al 1976).
When comparing the diet of mealworms to other organisms, grains make a nifty food source; typically abundant and found stored close together, there is never much to worry about such as running out or waiting for it to grow. Mealworms are relatively small organisms, so it doesn’t take a lot of grain to sustain them. In intraspecific competition, limited food sources can lead to the insect trying to locate a new food source (Svanback et al 2006). Mealworms are also decomposers so while grain is convenient, they can find food in a variety of places. In this experiment, the size of the container the mealworms are kept in and only one food source will prove to be an obstacle for them. There will be no way to discover new food sources. If there is only one food source, the mealworms (for either species) can’t avoid competition. In a 1946 study, researchers found that when the main nutrient supply ran out, 99% of eggs were consumed by adult insects and when that food source ran out they began to eat each other (Crombie 1946).
In interspecific competition, the two species of mealworms share a food source. T. molitor is a common meal worm and Z. morio takes on the name super worm. The main difference between these two species is size, with Z. morio being much larger. As mentioned earlier, grain is a common food source and it is rare that the source would be diminished to a point that the mealworms would have to be forced into competing.
In nature, why don’t insects that thrive on plants overtake and become an issue? Disease and predators are largely responsible for keeping those populations in check (Denno et al 1995). When two species are competing for a food source, the stronger species will most likely prey on the weaker when the resources become low. As with interspecific competition, it was suggested that with intraspecific competition the likeliest outcome will be niche diversification (Hairston et al 1960). This is a less likely outcome for the experiment due to limited space. Overall, organisms try and avoid conflict, they want to survive and reproduce. This pushes them to try and find new places to live, new things to derive nutrients from, or find a way to benefit others and establish a mutualistic relationship.
However, that is difficult considering the complex connections of any environment. Competition is created because two organisms with the same needs cannot survive in the same environment without a little bit of variation (Crombie 1946). This experiment allows for a closer look into how insects interact with each other and the complex world of how competition can shape populations of organisms. Due to a small controlled environment and a limited food source, both species will consume eggs and then turn to eating each other. This will be seen in both interspecific and intraspecific competition.