Glenurus gratus

Geographic Range

Glenurus gratus can be found in many regions of the United States including Florida, Indiana, Kentucky, Mississippi, Missouri, New Jersey, Ohio, Tennessee, and Wisconsin. The biogeographic region of Glenurus gratus is in the Neartic Region. (Miller and Stange, 2009; Coin, et al., 2010)

Habitat

This species of antlion has many different habitats, ranging from sandy areas such as dunes to hollowed out trees or on forest floors. Many of them can be found under hedges and in dark shady areas. (Coin, et al., 2010; Stange, 1980)

Physical Description

The larvae of Glenurus gratus has a mass of approximately 2.19 milligrams (mg) and can stretch up to 36 millimeters (mm) in length. Their mandibles are approximately 1 mm in width and they use these mandibles to trap their prey. The ends of the mandibles have suction tubes on them to make sure that their prey doesn’t get away. The adult G. gratus has a wing span of approximately 94 mm and a body length of approximately 61 mm. (Miller and Stange, 2009; Stange and Miller, 2006)

  • Sexual Dimorphism
  • sexes alike
  • Average mass
    .00000219 kg
    0.00 lb
  • Range length
    36 to 61 mm
    1.42 to 2.40 in
  • Average wingspan
    94 mm
    3.70 in

Development

Larvae can live up to approximately two years with the proper food and habitat. After the larval stage it creates a cocoon that can measure up to 13 mm in diameter. The process from larvae to adult can take up to 28 days. As an adult, Glenurus gratus grows wings and is similar to the body shape of a dragon fly and its wing span is approximately 94 mm. (Miller and Stange, 2009; Stange, 2000)

Reproduction

The eggs of G. gratus are buried in the sand and then hatch as larvae. (Stange and Miller, 2006)

After fertilization, the eggs hatch, emerging from the sand as larvae. (Stange and Miller, 2006)

No information was found regarding parental investment in this species.

Lifespan/Longevity

The larvae can live up to approximately two years with the proper food and habitat. Not much is known about overall longevity in antlions, but few live more than 2 years. (Coin, et al., 2010; Stange, 1980)

  • Range lifespan
    Status: wild
    1 to 2 years
  • Typical lifespan
    Status: wild
    1 to 2 years

Behavior

Mainly this species is found in tree holes. The larvae of Glenurus gratus lie and wait for prey in the hollows of trees. Adults are seen flying through forests. (Miller and Stange, 2009)

Communication and Perception

No types of communication are specifically known for Glenurus gratus, but it's likely that they utilize chemical and tactile communication.

Food Habits

Glenurus gratus has a very specific food habit. Their diet is mostly made up of ants and other small insects similar to ants. They capture the ant by making a pit in the sand that is approximately 15 millimeters in diameter. When an ant comes by and falls in the pit, the antlion takes its pincers and captures the ant. Then it uses a stinger in its pincers to poison the ant and paralyze it. Antlions eat approximately 22 ants per day. (Coin, et al., 2010; Stange and Miller, 2006; Stange, 2000)

  • Animal Foods
  • insects

Predation

Some known predators of Glenurus gratus are the red-tailed hawk, the green frog, the whooping crane and the ground squirrel. The larvae of G. gratus camouflages itself by its cone shape trap. (Miller and Stange, 2009)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Glenurus gratus are predators and feed on caterpillars, aphids, ants and other insect larvae. (Coin, et al., 2010; Stange, 1980)

Economic Importance for Humans: Positive

The larvae of Glenurus gratus trap and eat ants, which can be a pest to humans. (Miller and Stange, 2009)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

There is no known negative impact on the economic importance for humans besides the fact that Glenurus gratus can bite the skin of a human which is mildly uncomfortable. (Coin, et al., 2010)

  • Negative Impacts
  • injures humans
    • bites or stings

Conservation Status

Glenurus gratus does not have any special status for conservation.

Contributors

Chris Froehlich (author), University of Wisconsin-Stevens Point, Christopher Yahnke (editor), University of Wisconsin-Stevens Point, Renee Mulcrone (editor), Special Projects.

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

arboreal

Referring to an animal that lives in trees; tree-climbing.

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.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

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.

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

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

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.

insectivore

An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

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.

nocturnal

active during the night

oviparous

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

sedentary

remains in the same area

sexual

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

social

associates with others of its species; forms social groups.

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.

References

Coin, P., T. DiTerlizzi, V. Belov. 2010. "Species Glenurus gratus" (On-line). Bugguide.com. Accessed July 11, 2011 at http://bugguide.net/node/view/26625.

Miller, R., L. Stange. 2009. "An antlion, Glenurus gratus (Say) (Insecta: Neuroptera: Myrmeleontidae)" (On-line). Accessed July 11, 2011 at http://edis.ifas.ufl.edu/in708.

Ragland, E. 2010. "Nature's pitfall machine: antlions" (On-line). Accessed July 07, 2011 at http://bioweb.uwlax.edu/bio203/2010/ragland_evan/ant_lion_life_references.html.

Stange, L. 2000. Observations of the biology of the antlion genus Glenerus Hagen. Florida State Collection of Arthropods, 14/4: 228.

Stange, L. 1980. The Ant-Lions of Florida. The Ant-Lions of Florida, 221: 1.

Stange, L., R. Miller. 2006. "An antlion, Glenurus gratus" (On-line). Feature Creatures. Accessed July 11, 2011 at http://entnemdept.ufl.edu/creatures/misc/neuroptera/Glenurus_gratus.htm.