An aspect of exploration that may not be included in history texts is the introduction of living things from other places into the land being explored, such as insects and plants. While they may be harmless, the author places emphasis on those considered invasive, or hitchhikers. The author noted that invasive plants and animals can inflict economic and environmental damage. Examples of invasive insects included Colorado potato beetle and Silverleaf whitefly. As for invasive plants, examples were Emerald ash borer and Crapemyrtle bark scale.