Trimerotropis maritimaSeaside Locust

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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. (Otte, 1984)

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. (Otte, 1984)

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. (Bland, 2003; Capinera, et al., 2004; Otte, 1984; Vickery and Kevan, 1983)

  • Sexual Dimorphism
  • female larger
  • Range length
    24 to 43 mm
    0.94 to 1.69 in

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. (Otte, 1984)

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. (Steinberg and Wiley, 1983)

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. (Otte, 1984; Steinberg and Wiley, 1983)

  • Breeding season
    Seaside grasshoppers breed in late summer and early fall
  • Average age at sexual or reproductive maturity (female)
    10 months
  • Average age at sexual or reproductive maturity (male)
    10 months

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. (Otte, 1984)

  • Average lifespan
    Status: wild
    1 years

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. (Bland, 2003; Otte, 1984; Vickery and Kevan, 1983)

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. (Barimo and Young, 2002; Steinberg and Wiley, 1983)

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. (Barimo and Young, 2002; Capinera, et al., 2004; Otte, 1984; Vickery and Kevan, 1983)

  • 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. (Bland, 2003; Otte, 1984; Vickery and Kevan, 1983)

  • Anti-predator Adaptations
  • 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. (Barimo and Young, 2002; Bland, 2003; Otte, 1984; Vickery and Kevan, 1983)

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.

Contributors

George Hammond (author), Animal Diversity Web.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

diapause

a period of time when growth or development is suspended in insects and other invertebrates, it can usually only be ended the appropriate environmental stimulus.

diurnal
  1. active during the day, 2. lasting for one day.
ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

internal fertilization

fertilization takes place within the female's body

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

semelparous

offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

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 D Gwynne, G Morris, eds. 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.