How Butterfly Gardens Work

Threats to Butterflies

Even in a butterfly garden, both caterpillars and butterflies will encounter their fair share of tough breaks. During the larval stage, caterpillars (or larvae) are easy prey for fire ants, birds, flies and wasps. A faction of fire ants can devour a caterpillar in minutes. Funguses caused by damp, overcast days also endanger larvae, as does a loss of plant life caused by poor weather.

Butterflies have their own enemies: Birds, small mammals, lizards, snakes and spiders all prey on them. Extreme weather is another enemy of the cold-blooded animals, which are highly sensitive to temperature. At 40 degrees Fahrenheit (4 degrees Celsius) butterflies are completely immobile, and they can't fly until their internal temperature reaches 82 degrees Fahrenheit (28 degrees Celsius) [source: Ajilvsgi]. In addition, harsh winds and rains can beat butterflies down and drown them. Finally, both butterflies and caterpillars are sensitive to pesticide and herbicide use. Even the commonly used biological control agent Bt, often promoted as "safe and natural," poses dangers. Butterflies are so sensitive to pesticides that pollen from corn genetically modified with Bt has been transferred to other plants downwind and been shown to kill monarch butterfly larvae [source: Schappert].

Butterfly gardens can reduce these hazards, though, by providing a pesticide-free environment with easy access to sunlight and sheltering spots. On the next page, you'll learn in more detail how you can help caterpillars and butterflies thrive, and you'll also discover the four basic needs of every butterfly garden.