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Plagiometriona clavata

What do they look like?

Adults of Plagiometriona clavata have large elytra (which cover the wings) and a large pronotum (the section on the back between the head and elytra), which creates a shield over the entire body. This shield also covers the head. The shield looks like the shell of a tortoise. The elytra are clear with a brown design that is shaped like a teddy bear. The antennae are long and narrow, and stick out from underneath the shield. (Riley, 1986)

  • Sexual Dimorphism
  • sexes alike

Where do they live?

Plagiometriona clavata, the clavate tortoise beetle, is originally from the Nearctic region. It can be found throughout the east, central, and southern United States. (Barney, et al., 2007; Ciegler, 2007; Riley, 1986)

What kind of habitat do they need?

Plagiometriona clavata are leaf beetles that can be found on Solanum plants on farms or in gardens. They can also occasionally be found on the wild species of Solanum, usually in grasslands, meadows, and forests. (Riley, 1986)

  • These animals are found in the following types of habitat
  • terrestrial

How do they grow?

Plagiometriona clavata goes through complete metamorphosis. Its life stages are egg, larva, pupa, and then adult. Eggs are laid on host Solanum plants, and they hatch after several days. Larvae develop through 5 to 6 stages, called instars, before pupating, often on the host plant. After pupation, adults emerge. (Chaboo, 2007; Riley, 1986)

How do they reproduce?

Nothing is currently known about mating in this species.

Not much is known about mating in this species. It is likely that mating is similar to other known tortoise beetles. Adults mate and females lay eggs on the host plant. In the north, there is a single generation, but in the south, eggs are laid in multiple periods. (Chaboo, 2007; Riley, 1986)

  • How often does reproduction occur?
    P. clavata breeds once per summer in the north and 2 or more times in the south.
  • Breeding season
    Breeding occurs during the spring and summer for this species.

Little is known about parental care in this species. Females likely leave nutrients in the eggs for the offspring to grow and develop. After that, there is likely no more parental care.

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

How long do they live?

The adult lifespan of this species has not been recorded, but if it is similar to other tortoise beetles, Plagiometriona clavata likely lives a few weeks in the summer after becoming an adult. (Chaboo, 2007)

How do they behave?

The larvae of most tortoise beetles, including Plagiometriona clavata, build fecal shields. Instead of getting rid of their waste, it collects on a fork that sticks out of the end of their abdomen. The fork holds the feces above the body like an umbrella. This shield gets bigger as the larvae grows and continues to eat. The shield does not seem to hide the larvae from prey, but it does work to keep predators from attacking. The shields may actually attract potential parasitoids, which lay eggs in the body of other insects and eventually kill the insect host, but this is not known for sure. (Chaboo, 2007; Nogueira-de-Sa and Trigo, 2002; Nogueira-de-Sa and Trigo, 2005; Olmstead and Denno, 1992; Olmstead and Denno, 1993; Vencl, et al., 1999; Vencl, et al., 2005; Vencl, et al., 2011)

Home Range

These beetles stay close to areas of Solanum plants that they live on and eat. They are not active fliers, so they do not go far from these areas. (Chaboo, 2007; Riley, 1986)

How do they communicate with each other?

There is little information about communication in Plagiometriona clavata, but it is known that the fecal shields the larvae build produce chemicals that keep away predators. Adults likely communicate with other beetles with sight and chemicals. They also view their environment with sight, and detect chemicals in the environment. (Nogueira-de-Sa and Trigo, 2002; Nogueira-de-Sa and Trigo, 2005; Olmstead and Denno, 1992; Olmstead and Denno, 1993; Vencl, et al., 1999; Vencl, et al., 2005; Vencl, et al., 2011)

What do they eat?

Plagiometriona clavata eats several species of nightshade including Solanum dulcamara, S. americanum, S. carolinense, S. lycopersicum, S. pseudogracile, and S. tuberosum. Other plant hosts include species of Capsicum, Datura wrightii, and Datura stramonium. It eats the leaves of these plants. (Ciegler, 2007; Riley, 1986)

  • Plant Foods
  • leaves

What eats them and how do they avoid being eaten?

Plagiometriona clavata is eaten by ants, predatory Hemiptera insects, spiders and beetles as a larvae. For defense, larvae have a fork that extends from the end of their body that collects feces. While this does not camouflage the larvae, it does keep predators from attacking. Chemicals in the diet of the larvae, that are then present in the feces makes a chemical shield that repels predators. (Nogueira-de-Sa and Trigo, 2002; Nogueira-de-Sa and Trigo, 2005; Olmstead and Denno, 1992; Olmstead and Denno, 1993; Vencl, et al., 1999; Vencl, et al., 2005; Vencl, et al., 2011)

  • These animal colors help protect them
  • aposematic

What roles do they have in the ecosystem?

Plagiometriona clavata feeds on many Solanum plants, as well as several other plant species. However, it does not create enough damage to the plants to have any economic effect on farmers. It also prey for several different Arthropod predators. (Chaboo, 2007; Ciegler, 2007; Nogueira-de-Sa and Trigo, 2002; Nogueira-de-Sa and Trigo, 2005; Olmstead and Denno, 1992; Olmstead and Denno, 1993; Vencl, et al., 1999; Vencl, et al., 2005; Vencl, et al., 2011)

Species (or larger taxonomic groups) used as hosts by this species
  • Solanum dulcamara
  • Solanum americanum
  • Solanum carolinense
  • Solanum lycopersicum
  • Solanum pseudogracile
  • Solanum tuberosum
  • Capsicum sp.
  • Datura wrightii
  • Datura stramonium

Do they cause problems?

Even though Plagiometriona clavata does not currently cause much crop damage, it could become a crop pest in the future, which would cause economic loss for farmers.

  • Ways that these animals might be a problem for humans
  • crop pest

How do they interact with us?

Plagiometriona clavata could possibly be studied and used as a chemical control for insect pests. The process by which it uses chemicals from Solanum plants could be studied. (Vencl, et al., 1999)

Are they endangered?

Plagiometriona clavata is not an endangered species.

Contributors

Michael Leasia (author), University of Michigan Biological Station, Brian Scholtens (author), University of Michigan Biological Station, Angela Miner (editor), Animal Diversity Web Staff.

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

agricultural

living in landscapes dominated by human agriculture.

aposematic

having colors that act to protect the animal, often from predators. For example: animals that are bright red or yellow are often toxic or distasteful, their colors discourage predators from eating them.

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.

chaparral

mid-altitude coastal areas with mild, rainy winters and long, dry summers. Dominant plant types are dense, evergreen shrubs.

chemical

uses smells or other chemicals to communicate

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.

forest

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

herbivore

An animal that eats mainly plants or parts of plants.

heterothermic

animals that have little or no ability to regulate their body temperature, body temperatures fluctuate with the temperature of their environment, often referred to as 'cold-blooded'.

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.

oviparous

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

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

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

suburban

living in residential areas on the outskirts of large cities or towns.

terrestrial

Living on the ground.

tropical savanna and grassland
savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland
urban

living in cities and large towns, landscapes dominated by human structures and activity.

visual

uses sight to communicate

References

Barney, R., S. Clark, E. Riley. 2007. Annotated list of the leaf beetles (Coleoptera: Chrysomelidae) of Kentucky: Subfamily Cassidinae. Journal of the Kentucky Academy of Sciences, 68: 132-144.

Chaboo, C. 2007. Biology and phlogeny of the Cassidinae Gyllenhal sensu lato (tortoise and leaf-mining beetles) (Coleoptera: Chrysomelidae). Bulletin of the American Museum of Natural History, 305: 1-250.

Ciegler, J. 2007. Leaf and seed beetles of South Carolina (Coleoptera: Chrysomelidae and Orsodacnidae). Biota of South Carolina. Vol. 5. Clemson, SC: Clemson University.

Flinte, V., D. Windsor, L. Sekerka, M. de Macedo, R. Monteiro. 2010. Plagiometriona emarcida (Boheman, 1855) and Plagiometriona forcipata (Boheman, 1855)(Coleoptera: Chrysomelidae: Cassidinae), a single species differing in larval performance and adult phenotype. Journal of Natural History, 44: 891-904.

Nogueira-de-Sa, F., J. Trigo. 2002. Do fecal shields provide physical protection to larvae of the tortoise beetles Plagiometriona flavescens and Stolas chalybea against natural enemies?. Entomologia Experimentalis et Applicata, 104: 203-206.

Nogueira-de-Sa, F., J. Trigo. 2005. Faecal shield of the tortoise beetle Plagiometriona aff. flavescens (Chrysomelidae: Cassidinae) as chemically mediated defence against predators. Journal of Tropical Ecology, 21: 189-194.

Olmstead, K., R. Denno. 1992. Cost of shield defense for tortoise beetles (Coleoptera, Chrysomelidae). Ecological Entomology, 17: 237-243.

Olmstead, K., R. Denno. 1993. Effectiveness of tortoise beetle larval shields against different predator species. Ecology, 74: 1394-1405.

Riley, E. 1986. Review of the tortoise beetle genera of the tribe Cassidini occurring in America north of Mexico (Coleoptera: Chrysomelidae: Cassidinae). Journal of the New York Entomological Society, 94: 98-114.

Vencl, F., F. Nogueira-de-Sa, B. Allen, D. Windsor, D. Futuyma. 2005. Dietary specialization influences the efficacy of larval tortoise beetle shield defenses. Oecologia, 145: 404-414.

Vencl, F., P. Trillo, R. Geeta. 2011. Functional interactions among tortoise beetle larval defenses reveal trait suites and escalation. Behavioral Ecology and Sociobiology, 65: 227-239.

Vencl, F., M. Morton, R. Mumma, J. Schultz. 1999. Shield defense of a larval tortoise beetle. Journal of Chemical Ecology, 25/3: 549-566.

Virkki, N., J. Santiago-Blay, E. Riley. 1992. Chromosomes of Puerto Rican Hispinae and Cassidinae (Coleoptera, Chrysomelidae). The Coleopterist's Bulletin, 46: 29-42.

 
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Leasia, M. and B. Scholtens 2013. "Plagiometriona clavata" (On-line), Animal Diversity Web. Accessed April 19, 2014 at http://www.biokids.umich.edu/accounts/Plagiometriona_clavata/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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