Milkweed is most often thought of as the home and food source of monarch butterfly larvae. However, milkweed also hosts a wide variety of other insect species such as red milkweed beetles, milkweed aphids and a moth called the milkweed tussock (also known as the milkweed tiger moth). Just like monarchs, these species have evolved to be able to eat and accumulate milkweed toxins in their bodies as a defense mechanism. They also require milkweed as a food source in order to be able to complete their lifecycles.

Of the milkweed-feeding insects, milkweed tussock caterpillars can seem alarming because of their voracious appetites. Gardeners who grow milkweed specifically for monarch butterflies are often dismayed to find milkweed tussock caterpillars rapidly devouring their plants. This leads some people to question whether they are “good” bugs or if they should be killed to give monarchs a competitive advantage. Yet, milkweed tussock is a native species that evolved alongside the monarch. Knowing that species diversity is an essential part of a healthy ecosystem, there is no harm in leaving milkweed tussock caterpillars alone to eat a few milkweed plants.