Eastern Lubber Grasshopper Romalea microptera Beauvois Orthoptera Acrididae

Natural History

Distribution. This native grasshopper is common in the southeastern states from North Carolina to eastern Texas, including the entire peninsula of Florida.

Host Plants. Eastern lubber grasshopper has a broad host range. Jones et al. (1987) indicated that at least 26 species from 15 plant families containing shrubs, herbs, broadleaf weeds, and grasses are eaten. Watson (1941) indicated preference for pokeweed, Phytolaca americana; tread-softly, Cnidoscolus stimmulo-sus; pickerel weed, Pontederia cordata; lizard's tail, Saur-urus sp.; sedge, Cyperus; and arrowhead, Sagittaria spp. Although its preferred habitat seems to be low, wet areas in pastures and woods and along ditches, lubbers disperse long distances during the nymphal period. Lubbers are gregarious and flightless, their migrations sometimes bring large numbers into contact with crops where they damage vegetables, fruit trees, and ornamental plants. Lubbers seemingly display little preference among vegetable crops, feeding widely on whatever is available. In choice tests they favor broccoli, Brussels sprout, carrot, pea, and squash relative to other common vegetables. Watson and Brat-ley (1940) indicated preference for corn, cowpea, and peanut under field conditions. Also, they seek out and defoliate amaryllis, Amazon lily, crinum, narcissus, and related plants in flower gardens. In Florida, lubbers sometimes damage young citrus trees.

Natural Enemies. The natural enemies of lubber grasshoppers are poorly documented. Vertebrate predators such as birds and lizards learn to avoid these insects due to the production of toxic secretions. Naive vertebrates gag, regurgitate, and sometimes die following consumption of lubbers. However, loggerhead shrikes, Lanius ludovicianus Linnaeus, capture and cache lubbers by impaling them on thorns and the barbs of barbed-wire fence. After 1-2 days, the toxins degrade and the dead lubbers becomes edible to the shrikes (Yosef and Whitman, 1992). Undetermined flies and nematodes have been reported from lubbers, and it is possible to infect lubbers experimentally with the grasshopper-infecting nematode Mermis nigrescens (Poinar, 1979).

Life Cycle and Description. There is a single generation annually, with the egg stage overwintering. These grasshoppers are long-lived, and either nymphs or adults are present throughout most of the year in the southern portions of Florida. In northern Florida and along the Gulf Coast they may be found from March-April to about October-November.

  1. The eggs of lubber grasshoppers are yellowish or brown. They are elongate elliptical and measure about 9.5 mm long and 2.5 mm wide. The are laid in neatly arranged clusters or pods which consist of rows of eggs positioned parallel to one another, and held together by a secretion. Normally there are 30-50 eggs in each pod. Watson (1941) reported that ovipositing females preferred mixed broadleaf tree-pine habitats with intermediate soil moisture levels. He indicated that they avoided both lowland, moist, compact soil and upland dry, sandy soil. The female deposits the pod in the soil at a depth of 3-5 cm and closes the ovi-position hole with a frothy secretion or plug. The plug allows the young grasshoppers easy access to the soil surface when they hatch. Duration of the egg stage is 6-8 months.
  2. Young nymphs are highly gregarious, and remain gregarious through most of the nymphal period, though the intensity dissipates with time. Normally there are five instars, though occasionally six instars occurs. The nymphs are mostly black with a narrow median yellow stripe along the pronotum and abdomen, the edges of the pronotum, and on the lower side of the abdomen. The legs are well-marked with red. Their color pattern is distinctly different from the adult stage, and so the nymphs commonly are mistaken for a different species than the adult form. The early instars can be distinguished by a combination of body size, the number of antennal segments, and the form of the developing wings. The nymphs measure about 10-12, 16-20, 22-25, 30-40, and 35-45 mm long during instars 1-5, respectively. Antennal segments, which can be difficult to distinguish even with magnification, number 12, 14-16, 16-18, 20, and 20 per antenna during instars 1-5, respectively. The shape of the wing pads immediately behind the pronotum changes slightly with each molt. During the first instar the ventral surface is broadly rounded; during the second instar the ventral edges begin to narrow and point slightly posteriorly, and also acquire slight indication of wing veins; during the third instar the ventral edges of the wing pads
Romalea Guttata Reproduction

Adult eastern lubber grasshopper.

are markedly elongate, point strongly posteriorly, and the veins are pronounced. At the molt to the fourth instar the orientation of the small, developing wings shifts from pointing downward to upward, and posteriorly. In instar four the small front and hind wings are discrete and do not overlap, though the front wings may be completely or partly hidden beneath the pronotum. In instar five, the slightly larger wings overlap, appearing as a single pair of wings. Nymphs can complete instars 1-4 in about seven days each, with the terminal instar requiring 10 days. However, under cool conditions 60 days are required for nym-phal development. (See color figure 170.)

Adult. Adults are colorful, but their color pattern varies. In strong contrast to the nymph, the adult eastern lubber normally is mostly yellow or tawny, with black on the distal portion of the antennae, on the pro-notum, and on the abdominal segments. The front wings extend two-thirds to three-fourths the length of the abdomen. The hind wings are short and are incapable of providing lift for flight. The front wings tend to be pink or rose centrally, whereas the hind wings are entirely rose. Darker forms of this species also exist, wherein the yellow color becomes the minor rather than the major color component, and in northern Florida a predominantly black form is sometimes found. Adults attain a large size, males measuring 4355 mm long and females often measuring 50-70 mm, sometimes 90 mm. Both sexes stridulate by rubbing the forewing against the hind wing. When alarmed, lubbers spread their wings, hiss, and secrete foul-smelling froth from their spiracles. They can expel a fine spray of toxic chemicals to a distance of 15 cm. The chemical discharge from the tracheal system is believed to be an anti-predator defense, consisting of chemicals both synthesized and sequestered from the diet. Vertebrate, but not invertebrate, predators are affected (Whitman et al, 1991; 1992). (See color figure 169.)

The life history and ecology of eastern lubber grasshopper are poorly documented. Rehn and Grant (1961) provided important descriptive notes.

Damage

Lubber grasshoppers are defoliators, consuming the leaf tissue of numerous plants. They climb readily,

Adult eastern lubber grasshopper.

and as they are gregarious they can completely strip foliage from plants. More commonly, however, they eat irregular holes in vegetation and then move on to another leaf or plant.

Management

Management practices are not well developed. Insecticides applied to the foliage or directly to the grasshopper can be lethal. However, due to their large size they often prove difficult to kill. Insecticide treatment is more effective for young grasshoppers. As they are dispersive, and may continue to invade an area even after it is treated with insecticide, it is difficult to afford protection to plants. Bait formulations have not been evaluated.

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Responses

  • Leroy
    What is the name of the ventral surface of the eastern lubber grasshopper called?
    8 years ago
  • weldon
    Are eastern lubber grasshoppers bad for the environment?
    8 years ago
  • Ninfa
    Is the lubber grasshopper invertebrate or vertebrate?
    5 months ago

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