The Eastern Lubber Grasshopper, scientifically known as Romalea microptera, is a large, distinctly colored insect native to the southeastern United States. Its geographic range extends from North Carolina through Florida and west into Texas, inhabiting environments from wetlands to weedy fields. This species is a polyphagous herbivore, consuming a wide variety of plant material, but is notably flightless despite possessing small, rudimentary wings. Its immense size and clumsy movements earned it the common name “lubber,” derived from an old English word meaning “lazy” or “clumsy.”
Core Diet of the Adult Lubber
The adult lubber grasshopper is a broadly generalist feeder, consuming at least 100 plant species across 38 different plant families. The adults are capable of causing significant localized damage as they chew irregular holes in leaves and move between host plants.
Preferred ornamental plants often include those with thick, succulent foliage, such as amaryllis, crinum lilies, and narcissus, which are frequently defoliated. Adults also readily consume the leaves of oleander, canna, butterfly weed, lantana, and Mexican petunia. In agricultural settings, they show a clear preference for specific vegetable crops like peas, lettuce, kale, beans, and cabbage. However, they tend to avoid plants like tomato, pepper, eggplant, and sweet corn.
Beyond gardens and fields, the adult diet includes the foliage of several fruit trees, notably citrus, figs, and peaches. While they are polyphagous, they exhibit a strong preference for forbs, or broad-leaf plants, over grasses, which aligns with the structure of their mouthparts.
Nymph Diet Specializations
The nymph stages of the lubber grasshopper exhibit feeding behaviors and preferences distinct from those of the adults, reflecting their lower mobility. Nymphs hatch in the spring and are often found clustered together, a gregarious feeding habit that can lead to the complete defoliation of a single host plant. These young grasshoppers initially remain close to the moist, low-lying areas where they hatch, such as drainage ditches, swamps, and marshes.
Their early diet relies heavily on tender, low-growing plants and semi-aquatic vegetation, including species like pickerel weed and arrowhead. Specific plants like narcissus, swamp lilies (Crinum americanum), and pokeberry are known to be preferential food sources for the early instars. As they grow and become more mobile, the nymphs disperse from these initial breeding grounds, transitioning from their localized, specialized diet to the broader range of plants consumed by the adults.
The Role of Toxins in Food Selection
The lubber grasshopper’s food choices are not solely about nutrition but are also fundamentally linked to its defense mechanisms against predators. The insect employs a strategy known as aposematism, where its striking bright coloration—typically yellow, black, and sometimes red—serves as a warning sign to vertebrate predators. This warning is supported by a powerful chemical defense system.
The grasshopper’s body can sequester toxic compounds from the plants it consumes, primarily cardiac glycosides, also known as cardenolides. These compounds, which interfere with heart function in many animals, are derived from specific host plants, such as oleander and certain milkweeds like butterfly weed (Asclepias species). The ability to accumulate these toxins makes the lubber distasteful and potentially poisonous to birds, lizards, and small mammals.
When threatened, the lubber can expel a noxious, bubbly foam from its thoracic spiracles, enveloping itself in a chemical cloud derived from these sequestered plant compounds, along with synthesized phenolics. By consuming these toxic plants without being harmed themselves, the grasshoppers acquire a highly effective deterrent, securing a relatively predator-free ecological niche.