Artificial Butterfly Diets
Joshua Yu, Tasheal Gill
Sir Charles Tupper
Floor Location : M 086 V
This project is to determine the positive or negative side effects of breeding Painted Lady Butterflies using artificial diets (Stonefly Heliothis diet, species specific), compared to their natural diet of host plant leaves (hollyhock plant leaves). The experiment will indicate which diet should be used to increase declining butterfly populations.
Because of declining butterfly populations in British Columbia and all over the world, an artificial diet was made to increase populations not only during the summer breeding months when host plants were available, but also during the winter months as well. Thus, more adults can be reintroduced to the wild when appropriate. However, problems of mutations and weakening of the adult butterflies have resulted from many butterfly farmers using the artificial diet. These side effects can negatively impact local populations instead of strengthening them and put these important pollinators at even more a risk. The artificial diet will be deemed to be beneficial or the opposite by recording the growth rate, pupae length, wingspan, hatch rate of the second generation, and mortality rate of each stage. Our hypothesis being that butterflies bred on the artificial diet would be smaller in all stages, take longer to mature, and have higher mortality.
Host plants, or hollyhock plants, were grown in a green house made with reflecting walls and fluorescent lamps to make sure all plants had the same nutrient content and were grown in the same conditions before the testing began. The experiment needed live Painted Lady Butterfly eggs (from a biological supply company) and the developed larvae that hatched were separated in two groups that were fed an artificial diet and a natural diet of hollyhock plant leaves. They were grown to an adult stage, allowed to lay eggs, and data was recorded when needed. All stages were kept at a controlled 75 degrees Fahrenheit at all times and had a constant access to food. This experiment was repeated for three times to ensure accurate results.
After all data was collected the results had shown that our hypothesis was correct and artificially raised butterflies had significantly smaller pupae and wingspan average than the ones raised on a natural diet. Their offspring also had a lower hatch rate, however, mortality was decreased during the maturing stages of larva, to pupa, to adult and took less time to become adults. This part of our hypothesis was rejected. We assume that natural selection has guaranteed that only the strongest and healthiest adults ever survive to reproduce and pass on healthy genes and larvae that were not to survive died within the early larval stages. Many mutations were present and were the main cause for mortality during the pupa and adult stages for artificially bred butterflies. Mutations included shriveled pupae, undersized adults, and adults not being able to feed properly and did not live for 24 hours. High humidity was concluded to be the main cause and could be avoided in future experiments with adding a polyacrylamide (high absorbent polymer) to the diet to absorb excess humidity, which we had learned from further research.
Our conclusion was that the artificial diet presented many negative side effects for breeding the Painted Lady Butterfly even though it proved to yield higher numbers of adults in the end. The natural diet made butterflies become more healthy, larger, and have higher amounts of offspring, which would be more beneficial to boosting declining populations. Captive breeding of Painted Lady Butterflies should use natural host plant material to introduce the healthiest individuals into the wild and prevent weakening and damaging local pre-existing populations.