common name: eastern lubber grasshopper
scientific name: Romalea microptera (Beauvois) (= guttata (Houttuyn)) (Insecta: Orthoptera: Acrididae)
Introduction - Description - Life Cycle - Habitat and Hosts - Defensive Characteristics - Management - Selected References
Periodically, grasshoppers have been of economic importance in Florida. A few species may occur in large enough numbers to cause serious damage to citrus, vegetable crops and landscape ornamentals. One of the species most commonly causing damage is the eastern lubber grasshopper, Romalea microptera (Beauvois), also known as Romalea guttata (Houttuyn).
The eastern lubber grasshopper is limited to the southeastern and south central portion of the United States. The northern boundary is central North Carolina west through southern Tennessee, Georgia, Alabama, Mississippi, Louisiana, Arkansas, to Texas. It occurs throughout Florida.
Figure 1. Distribution of Romalea microptera, the eastern lubber grasshopper.
The eastern lubber is surely the most distinctive grasshopper species in the southeastern United States. It is well known both for its size and its unique coloration. The wings offer little help with mobility for they are rarely more than half the length of the abdomen. This species is incapable of flight and can jump only short distances.The eastern lubber is quite clumsy and slow in movement and mostly travels by walking and crawling feebly over the substrate. The “lubber” designation is interesting because it aptly describes this grasshopper. “Lubber” is derived from an old English word “lobre” which means lazy or clumsy. This term has come to mean a big, clumsy, and stupid person, also known as a lout or lummox. In modern times, it is normally used only by seafarers, who term novices “landlubbers”. Eastern lubber is one of only four species in the family Romaleidae found north of Mexico, but there are many other species in South America, and many are winged and agile, so although some other species in this family are called lubbers, the “lubber” designation is not appropriate for the entire family.
Eggs. Eggs are produced about a month after emergence of the adults. According to Hunter-Jones (1967), females each produce 3-5 egg clusters in structures called pods. The pod is not much more than tightly packed eggs surrounded by rigid, frothy material, with most of the froth deposited at the tip of the pod closest to the surface. The froth allows an easy exit for the young hoppers as they can readily wiggle through this as they hatch. The interval between egg pod production by a females is about 2 weeks. Hunter-Jones reported egg production of 30-80 eggs per pod, averaging about 60 eggs per pod. Egg production was greater under solitary than crowded conditions. On the other hand, under field conditions Stauffer and Whitman (2007) reported egg production of 25-50 eggs per pod, with only 1-3 pods per female. Egg production in the laboratory was greater than in the field. The eggs require a cool period (e.g., 20°C for 3 months) but then will hatch when exposed to warmer temperatures.
Nymphs. The immature eastern lubber grasshopper differs dramatically in appearance from the adults. Nymphs (immature grasshoppers) typically are almost completely black, but with a distinctive yellow, orange, or red stripe located dorsally. The hopper’s face, edge of the pronotum, and abdominal segments also may contain reddish accents. Often the reddish accents change to yellow over the course of development. When they first molt, the young hoppers may be brownish, but they soon darken to black.
As they mature, the nymphs change slightly in appearance; the instar is easily determined by examination of the developing wings. Initially (instars 1-3), the general orientation of the wing tips is to point ventrally, whereas after the third instar the orientation reverses, pointing dorsally. In the first instar, the tips of the meso- and metathoracic wingbuds are not elongated, and lack wing veins. In the second instar, the wing buds develop weak evidence of veins along the ventral margin, and in the third the mesothoracic wings point slightly posteriorly but maintain their ventral orientation. After the reversal of orientation, the wing buds are discernable wings, albeit small. The wings of the fourth instar barely extend posteriorly to reach the tympanum (oval acoustic structure) and the anterior margin of the first abdominal segment. The wings of the fifth instar extend as far posteriorly as the posterior margin of the tympanum and the posterior margin of the first abdominal segment. Even in the fifth instar, however, the wing buds do not overlap and cover the tympanum. In adults, the wings overlap and cover the tympanum, extending posteriorly to cover 3-4 abdominal segments.
Figure 2. Young lubber, Romalea microptera (Beauvois), instar one. The segments above the second and third legs bear wing buds, though at this stage they are hardly visible. Photograph by Lyle J. Buss, University of Florida.
Figure 3. Young lubber, Romalea microptera (Beauvois), instar two. The beginnings of the wing veins can be seen now. Photograph by Lyle J. Buss, University of Florida.
Figure 4. Young lubber, Romalea microptera (Beauvois), instar three. Now you can better see the developing veins and a slight backward (posterior) extension of the wing buds. Photograph by Lyle J. Buss, University of Florida.
Figure 5. Young lubber, Romalea microptera (Beauvois), instar four. Now you can see something that actually looks like a wing, although it is quite small. Note that it is pointed upward (dorsally). Also note its length relative to the oval, reddish-colored tympanum on the first abdominal segment. Photograph by Lyle J. Buss, University of Florida.
Figure 6. Young lubber, Romalea microptera (Beauvois), instar five. The wing is longer now, extending further posteriorly relative to the tympanum. Next it will molt to the adult, though you cannot tell from the nymph what color form will be assumed by the adult. Photograph by John Capinera, University of Florida.
The nymphs often are found in aggregations, and ascend vegetation to roost, especially at night. Presumably this behavior removes them from ready access by night-active ground-dwelling predators, though they reportedly are well defended chemically (see defensive characteristics, below).
Figure 7. Lubber nymph Romalea microptera (Beauvois), molting, leaving behind its old (darker) body covering. Photograph by Lyle J. Buss, University of Florida.
Adults. Adult males and females are usually 6.0 and 8.0 cm. long, respectively. The body is quite robust while the legs remain relatively slender. The general color of adults is dull yellow with varying degrees of black spots and markings. The front pair of wings (tegmina) are yellow with numerous scattered black dots, while the hind wings when exposed reveal a bright red/rose coloration with a black border. The color of adult lubbers also varies throughout most of the insect’s range. One phase is nearly entirely black (melanic) with a few marks of yellowish. The adults of this melanic phase seem to resemble the nymph, but only in color. Individuals in the same geographic area may be yellowish, melanic, or somewhere in between. However, despite their different appearances, these different-appearing grasshoppers are the same species and will mate successfully.
Figure 8. Adult eastern lubber grasshopper, Romalea microptera (Beauvois), light color phase. Photograph by John Capinera, University of Florida.
The color of adult lubbers also varies throughout most of the insect's range. One phase is nearly entirely black with a few marks of yellowish tawny. The adults of this phase seem to resemble the nymph. However, the different phases are indeed the same species.
Figure 9. Adult eastern lubber grasshopper, Romalea microptera (Beauvois), intermediate color phase. Photograph by John Capinera, University of Florida.
Figure 10. Adult eastern lubber grasshopper, Romalea microptera (Beauvois), dark color phase. Photograph by John Capinera, University of Florida.
Figure 11. Black color form of adult eastern lubber grasshopper, Romalea microptera (Beauvois). Photograph by Lyle J. Buss, University of Florida.
Adult Romalea microptera exist nearly throughout the year in Florida with their numbers dwindling during the fall and winter period. They have one generation per year, with eggs beginning to hatch in February in South Florida while the rest of the state usually doesn't see this species until March or later. Eastern lubbers, like all grasshoppers, molt and grow repeatedly before attaining maturity. These immature stages (instars) are referred to as nymphs. Lubbers normally have a total of five instars before molting into the adult stage, though some females have six instars. The length of these instars varies with temperature, but at 30°C the development times are about 10-12, 8-9, 10, 10, and 15-16 for instars 1-5, respectively (Hunter-Jones 1967). In Florida, the highest number of adults can be observed during the months of July and August.
After mating, females will begin laying eggs during the summer months. The male usually guards the ovipositing female, sometimes for more than a day. The timing of oviposition is highly variable, but ovipositing females select open, sunny areas of higher elevation, then use the tip of the abdomen to dig a small hole into a suitable patch of soil. Usually at a shallow depth, but sometimes up to a depth of about 5 cm, she will deposit her eggs within a light foamy froth. These eggs will remain in the soil through late fall and winter and then begin hatching in Spring. The young grasshoppers crawl up out of the soil upon hatching and congregate near suitable food sources. Lubbers are often found in damp or wet habitats, but seek drier sites for egg-laying.
Figure 12. Mating adults of two color forms. Photograph by Lyle J. Buss, University of Florida.
Populations cycle up and down, possibly due to the action of parasites. The tachinid fly Anisia serotina (Reinhard) attains high levels of parasitism, sometimes 60-90%. We have also found the sarcophagids Blaesoxipha opifera (Coquillett) and Blaesoxipha hunter (Hough) parasitizing this grasshopper, sometimes at high incidences of parasitism (unpublished; identified by G.A. Dahlem, Northern Kentucky University). A gregarine parasite, Boliviana floridensis (Protozoa: Eugregarinidia) can be found in their gut (Stauffer and Whitman 2007).
Figure 13. One of the species of parasitic flies (Blaesoxipha hunteri) that affects lubbers. The larvae develop within the nymphs, killing their hosts when they emerge. Photograph by Lyle J. Buss, University of Florida.
Eastern lubber grasshoppers seem to prefer open pine-woods, weedy fields and the weedy vegetation along roadsides. Occasionally, on rural highways in the central portion of the state, enough flattened lubber grasshoppers will accumulate on the road to cause a minor slick. Watson (1941) suggested that lubbers avoided both low, wet sites and elevated, extremely dry sites when ovipositing. He observed that the interface between mesic hardwood communities and more xeric pine-dominated forests are preferred oviposition sites.
The accumulation of weedy plant species along drainage ditches within citrus groves and vegetable fields will sometimes attract lubbers, which in turn end up feeding on the cultivated crops as well. Lubbers often invade residential areas and feast on flowering plants, especially amaryllis, narcissus, and crinum (all family Amaryllidaceae) (Watson 1941). These grasshoppers will migrate long distances to obtain preferred food, sometimes forming trails and following one another. The host preferences of lubbers are not well documented, though they clearly are generalists, capable of feeding on many plants. Watson (1941) reports that, in addition to the aforementioned flowers, they accept tread softly, Cnidoscolous stimulosus (Euphorbiaceae) and pokeberry, Phytolaca americana (Phytolaccaceae) in mesic habitats, and pickerel weed, Pontederia cordata (Pontederiaceae), lizard’s tail, Saururus cernuus (Saururaceae), broadleaf arrowhead, Sagittaria latifolia (Alismataceae), and Cyperus (Cyperaceae) in moist or wet areas. The crop most often affected in Florida is citrus, though typically it is mostly the small, newly planted trees that are adversely affected. Other fruit trees and many vegetables also are susceptible to damage.
Young lubbers (various instars) in citrus grove. Video by John Capinera, University of Florida.
Barbara and Capinera (2003) studied suitability of poison bait for lubber control (see Management of Lubbers). As part of this investigation, they compared the acceptance of various vegetable crops to bran bait, thus obtaining relative preference values for many crops. Crops in the plant families Brassicaceae, Asteraceae, Cucurbitaceae, and Apiaceae were relatively preferred by lubbers. Thus, cauliflower, collards, lettuce, carrot, onions, and squash were relatively favored by lubbers. In contrast, Solanaceae was not very preferred, so peppers, tomatoes and eggplants are less likely to be consumed.
Adults of eastern lubber grasshoppers possess a variety of abilities to defend themselves. Their bright color pattern is a warning to predators that the lubber contains toxic substances. Indeed, there are several records attributing the demise of individual birds failure to exercise caution when selecting prey items. Also, small mammals such as opossums have been known to vomit violently after ingesting a lubber, and to remain ill for several hours. However, shrikes are reported to catch and kill lubbers.
If the red, yellow, and black coloration fails to keep a predator at bay, when contacted the lubber may produce a phenolic secretion from a special thoracic gland, first as a dispersant spray and then as a frothy secretion. This exudate consists of a number of phenolic and quinone compounds, some of which are irritants or toxins that deter predation by vertebrates and ants (Jones et al. 1987, Whitman et al. 1991). The exact nature of the toxic properties varies, as these grasshoppers assimilate different compounds depending on the plants they ingest. This bubbly froth is accompanied by a relatively loud hissing sound. The insect contracts the abdomen to force air out of the spiracles along with the defensive secretion. The sound is produced as the spray is being forced out of these tiny holes in the thorax called spiracles. These defensive behaviors seem to be limited to the adult stage.
The size of the eastern lubber grasshopper is a little misleading when one considers they require far less food material than most of the more injurious species of grasshoppers that are only one-third as large or smaller. Thus, they do less damage than one might expect.
Grasshopper abundance can be regulated through management of the vegetation. If you deprive grasshoppers of their favored food, often they will leave or perish. Keeping the vegetation mowed is very helpful, as short vegetation does not often support grasshoppers
Lubber grasshoppers will often develop initially in moist areas around ponds and irrigation ditches, then later migrate to homes, yards, and crops. Rather than waiting for the grasshoppers to come to you, it is often best to take the battle to them. So check potential breeding or feeding sites for signs of grasshoppers. The young grasshoppers remain clustered in groups, but as they get older they are more likely to be solitary. If you cannot control them through mowing, try hand-picking. You can throw them into a bucket of soapy water or a trash bag to kill them.
Figure 14. Young nymphs of the eastern lubber grasshopper, Romalea microptera (Beauvois), clustered on a citrus reset (young citrus tree). Photograph by John Capinera, University of Florida.
If there are too many to control by hand-picking, insecticides can be applied. Lubber grasshoppers are not easy to kill, even with insecticides, once they become large. Among the insecticides that will kill lubber grasshoppers are many pyrethroid insecticides. You likely will have to apply the insecticide directly to the insects; the small amount of insecticide residue remaining on sprayed plants may not be adequate to kill the grasshoppers.
Insecticide-containing baits are often used for grasshopper control. Bran bait containing corn oil and insecticide is attractive to lubbers, and they will perish after eating only a small amount of toxicant (Barbara and Capinera 2003). However, if there is highly attractive vegetation the lubbers will be less likely to eat the bait, so bait applications are most effective when applied to areas lacking competitive vegetation, or interspersed among less preferred vegetation. For example, insecticide bait might be scattered on bare soil surrounding a vegetable garden to encourage the hoppers to consume bait before they contact the crops.
If insecticides are to be used, be sure to apply them according to the directions on the label of the container. Especially if insecticides are applied to food crops or near water, it is important to heed the directions. Many insecticides are toxic to fish, so it is imperative that open water be avoided.
Grasshoppers are much easier to control when they are nymphs. As they mature, and grow larger, higher rates of toxicants must be applied for effective control.
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