Genetically Modifying Butterflies

Humans are not the only species which create genetically modified organisms; braconid wasps are successfully passing down their DNA to the caterpillars of butterflies and moths. Braconid wasps are parasitic insects which lay their eggs inside of caterpillars. The wasp larvae then feeds off of the caterpillar, often killing its host. Not only do the larvae feed off the host, but they also inject a bracovirus, which provides protection against the caterpillars' immune system. Occasionally the caterpillar is able to survive the infestation by killing the larvae; when this happens the bracovirus remains in the caterpillar's DNA, often leaving behind tag-along genes. Then when that caterpillar becomes a butterfly and reproduces, it passes down the wasp's genes.Some of these genes turn out to help butterflies survive; one of the wasp genes provide the affected butterfly protection against baculoviruses. Baculoviruses are often used in pesticides. If the traits inherited by wasps were harmful, then they would probably be eradicated via natural selection, but since they are helpful, they are found in many species of butterflies and moths.

The goal of reproduction is to pass one's genes down to the next generation. Considering that goal, the braconid wasp is very successful; not only do they pass down their genes to the next generation of wasps, but they also pass down their genes to other insects. I feel like the relationship between these two organisms is almost mutralistic; the wasp benefits by producing offspring, while the caterpillar benefits by obtaining superior genes. But, despite my idealistic view, clearly this scenario is not a form of mutralism, due to the deaths which most of the infested caterpillars face. Also I find it amazing that caterpillars are able to acquire these genes, since the the two species' lineage diverged about 300 million years ago. Also I am surprised that a mutation of this nature would not cause sterility to the butterflies. Usually hybrids are sterile, but this form of mutation must not behave in that fashion. Overall, it is very intriguing that certain parasites can alter their host's DNA with such ease.

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