Trimerotropis maritima

Geographic Range

Trimerotropis maritima is found in eastern and central North America. The northern boundary of its range runs roughly from southern Maine west through southwestern Ontario, lower Michigan, and Wisconsin to the banks of the upper Mississippi River. From there the approximate limit of its range runs southwest to northeastern Arizona, and then southeast to the Gulf Coast of Texas, possibly further south into Tamaulipas. South and east of these boundaries this species occurs all the way to the shores of the Atlantic Ocean and Gulf of Mexico.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Trimerotropis maritima is found mainly in arid, open, sandy areas with little vegetation. It is most abundant on sandy sea and lake shores, and open sandy river banks, but also occurs along gravel roads and in bare open fields. Members of this species seem to strongly prefer bare ground.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• desert or dune desert or dune

• Aquatic Biomes
• coastal coastal

• Other Habitat Features
• agricultural agricultural
• riparian riparian

Physical Description

This is a medium-sized grasshopper: length from head to end of folded forewings is usually 24-36 mm in males, 31-43 mm in females. The background color of nymphs and adults ranges from light gray to medium gray-brown, and they are marked with darker brown speckles all over the head, body, legs, and forewings. The degree of speckling is quite variable, even at a single location, but it generally good camouflage. The hind tibia are yellow or orange, and the inner faces of the hind femora have two complete black bands. The basal third of each hindwing is yellow, with a wide black or dark brown band on the outer edge of the yellow portion. The remainder of the wing is clear.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger

Development

Like all grasshoppers, Trimerotropis maritima is hemimetabolous. The nymphs that hatch from eggs in the spring resemble the adult form, though their wings are just small pads, and their reproductive organs are not complete. They molt several times as they grow in the spring and summer, and complete their final molt to adulthood in late summer. In this last molt, the wings and reproductive structures are complete, and they stop growing and do not molt again. Only eggs survive the winter.

• Development - Life Cycle
• diapause diapause

Reproduction

Males of Trimerotropis maritima advertise their presence to females with short display flights. In these flights they flash their colored hindwings, and snap them to produce a soft rattling sound (this form of sound production is called crepitation). Males also actively search for potential mates. When in closer content, males court females with chirps (rubbing their hind leg on their front wing) and rapid movements of his hind legs. Females may respond with hind leg movements as well. Both sexes will attempt to mate with more than one partner during their adult lives.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

In most of their their range, these grasshoppers breed in the late summer and early fall, until temperatures become too cold for activity and survival.

During mating, the male transfers a spermatophore into the female. This structure contains sperm, and also a mass of protein that may be absorbed by the female and used for egg production. The presence of a spermatophore also may prevent a female from mating again until it is absorbed.

Females probably lay eggs in clusters, surrounded by a later of foam that quickly hardens. They may insert their eggpod into the sand at the base of dune grasses and similar plants.

• Key Reproductive Features
• semelparous semelparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • internal internal
• oviparous oviparous

Males provide some nourishment to their mate (and potentially to their offspring) via the spermatophore. Females spend energy provisioning their eggs, locating a suitable spot for oviposition, and secreting the protective foam that forms the eggpod. There is no further investment after the eggs are laid.

• Parental Investment
• pre-fertilization
  • provisioning
• pre-hatching/birth
  • provisioning
    • male
    • female

Lifespan/Longevity

In most of their range, Trimerotropis maritima adults cannot survive winter temperatures, so live for no more than a year. It's possible that at the extreme southern portion of their range, they might live longer.

Behavior

Except for mating behavior, Trimerotropis maritima is not a social species. Both nymphs and adults are very cryptic, blending in with the sandy background. At night they sometimes bury themselves in sand, with only their heads exposed, perhaps to take advantage of warm sand to keep their body temperature higher when the air temperature drops. Adult seaside grasshoppers are considered strong flyers, but they are not migratory, and tend to stay close to their preferred open sand habitat.

• Key Behaviors
• flies
• saltatorial saltatorial
• diurnal diurnal
• motile motile
• sedentary sedentary
• hibernation hibernation
• solitary solitary

Communication and Perception

These grasshoppers have relatively well-developed auditory senses, used in courtship. Males signal to females by snapping their wings in flight (crepitation) and by rapid motions of their legs against their wings (chirping) and against the ground. Both males and females signal to other seaside grasshoppers with motions of the hind legs. Males can distinguish motionless females quickly enough that some kind of pheromone is likely to be involved.

Trimerotropis maritima has large compound eyes, and uses vision to identify moving threats and to locate other members of its species. Nymphs and adults have a sense of taste that they use to choose food plants.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• pheromones pheromones
• vibrations vibrations

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• vibrations vibrations
• chemical chemical

Food Habits

Trimerotropis maritima is an herbivorous species that feeds primarily on the leaves of grasses, such as Ammophila . It may occasionally eat fruit, flowers, and the leaves of some broad-leaved plants as well.

• Primary Diet
• herbivore herbivore
  • folivore folivore

• Plant Foods
• leaves
• fruit
• flowers

Predation

This species relies on its cryptic coloration as its primary defense against predators. Nymphs can jump quickly, and adults will fly if approached to closely. They prefer to land on sand, rather than vegetation, probably to better use their camouflage. We have no information on the particular predators of this species. There is no indication that Trimerotropis maritima has chemical defenses, so probably any insectivorous predator that can catch one might eat it.

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

The grasshoppers can occur in high enough densities that their feeding might affect the abundance and community structure of grasses and other plants that colonize bare sandy habitats.

This species is found on the shores of the Great Lakes, and uses the same habitat type as the Lake Huron locust, Trimerotropis huroniana . However, the two species have not been found to co-occur. Trimerotropis maritima occupies the southern shores of Lakes Michigan and Huron, also the shores of Lake St. Clair, Lake Erie and Lake Ontario. T. huroniana is found on the sandy portions of the around the north half of Lakes Huron and Michigan. The mechanism of exclusion, whether it is competition or some other factor, has not been determined.

Economic Importance for Humans: Positive

This species is not known to provide direct benefits to humans.

Economic Importance for Humans: Negative

here are no known adverse effects of Trimerotropis maritima on humans.

Conservation Status

Taken as a whole Trimerotropis maritima is not considered to be in need of special conservation efforts. However, it's preferred habitat is often subject to destructive development or mining, specially along coastlines. Isolated populations in some areas, including some Great Lakes shorelines, have been identified as deserving special concern.

Additional Links

Encyclopedia of Life

Contributors

George Hammond (author), Animal Diversity Web.

References

Barimo, J., D. Young. 2002. Grasshopper (Orthoptera: Acrididae)—plant-environmental interactions in relation to zonation on an Atlantic coast barrier island. Environmental Entomology , 31(6): 1158-1167. Accessed April 08, 2009 at http://www.entsoc.org/pubs/periodicals/ee/index.htm .

Bland, R. 2003. The Orthoptera of Michigan . East Lansing, Michigan, USA: Michigan State University Extension. Accessed April 07, 2009 at http://www.emdc.msue.msu.edu .

Capinera, J., R. Scott, T. Walker. 2004. Field Guide to Grasshoppers, Katydids, and Crickets of the United States . Ithaca, New York, USA: Comstock Publishing Associates.

Otte, D. 1984. The North American Grasshoppers, volume II (Acrididae: Oedipodinae) . Cambridge, Massachusetts, USA: Harvard University Press.

Steinberg, J., R. Wiley. 1983. The mating system of Trimerotropis maritima (Acrididae: Oepodinae). Pp. 285-304 in Orthopteran Mating Systems . Boulder, Colorado, USA: Westview Press, Inc..

Vickery, V., D. Kevan. 1983. A Monograph of the Orthopteroid Insects of Canada and Adjacent Regions . Ste. Anne de Bellevue, Quebec, Canada: Lyman Entomological Museum and Research Laboratory.