Complex sentence: The only source of energy for overwintering forest tent caterpillar eggs comes from the parental generation and as a result, overwintering performance of the insect should be viewed in the context of parental fitness.
Split into simpler sentences: The only source of energy for overwintering forest tent caterpillar eggs comes from the parental generation. As a result, overwintering performance of the insect should be viewed in the context of parental fitness.