Lettuce Lake's Lepidoptera

As you stroll along the boardwalk at Lettuce LakeConservation Park, you may spot the seasonal blossoming of spotted water hemlock plants (Cicuta maculata). These small, umbrella-like clusters of flowers sit atop tall, branching stems. While these plants are toxic and inedible for humans, imagine your surprise as you discover caterpillars, resembling emerald gemstones, feasting on the flowers.

Photo by Dr. Don Hall, University of Florida

These caterpillars, exhibiting a stunning combination of green, black, and yellow hues, are the larval stage of the Eastern Black Swallowtail butterflies (Papilio polyxenes). They primarily feed on plants such as the spotted water hemlock, which serve as essential host plants for their survival and growth. Host plants are crucial for many butterfly species, providing both sustenance and a secure habitat for caterpillars to mature and eventually transform.

Photo by Dr. Don Hall, University of Florida

You might be surprised to find butterflies on a lake. In reality, the boardwalk at Lettuce Lake Conservation Park is situated in a riparian zone or floodplain, where the waters of the Hillsborough River flow into the park's unique wetlands. The park's hydrology is distinct from that of an actual lake, with water levels fluctuating seasonally and moving as an extension of the river. This dynamic environment allows wetland plants like the hemlock to grow and provides habitat for the Eastern Black Swallowtail caterpillars.

Photo by Dr. Don Hall, University of Florida

During your visit, you may notice that the blooming stalks have already been consumed by caterpillars, who have seemingly vanished. The density of wetland plants and frequent drops in riparian water levels allow these caterpillars to embark on a remarkable journey. Once they have reached full size, they often search for nearby sturdy plants or structures. Keep an eye out for hidden chrysalises on the boardwalk and nearby Buttonbush Trees (Cephalanthus occidentalis). Inside these inconspicuous brown or grey pupae, the caterpillars undergo their incredible transformation into Swallowtail Butterflies. Be sure to look, but don't touch, as the delicate silk threads attaching them to surfaces are essential for their emergence and can be easily broken.

Photo by Dr. Don Hall, University of Florida

As temperatures drop later in the year, you may notice that the weather around Lettuce Lake does not get as cold as in other areas. Wetlands like Lettuce Lake Conservation Park can form microclimates that are warmer than their surroundings. Since butterflies are ectothermic, their body temperature depends on the ambient temperature; they may be unable to fly when the temperature drops below 60 degrees. Wetlands provide safe havens for butterflies to overwinter, playing a critical role in their long-term survival.

Photo by Dr. Don Hall, University of Florida

By visiting and supporting Hillsborough County's Conservation Parks and Nature Preserves you are not only safeguarding the existence of Eastern Black Swallowtail butterflies, but also securing our planet's future. Wetlands act as natural filters, purifying water and providing habitats for various species of plants, insects, and animals. The unique interdependence of these species within the wetlands ensures a thriving and balanced ecosystem, keeping the water we depend on secure, clean, and productive.

So, the next time you find yourself walking along the boardwalk at Lettuce Lake Conservation Park or exploring other nature preserves in Hillsborough County, take a moment to appreciate the beauty and importance of wetland habitats. Keep your eyes peeled for the intricate white blooms, which signify the presence of butterflies.