Critter Catalog

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)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• 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)

• Biogeographic Regions
• nearctic
  • native

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

• Terrestrial Biomes
• savanna or grassland
• chaparral
• forest
• scrub forest

• Other Habitat Features
• urban
• suburban
• agricultural

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)

• Development - Life Cycle
• metamorphosis
• diapause

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)

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

• 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)

• Key Behaviors
• flies
• diurnal
• motile
• sedentary

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)

• Communication Channels
• visual
• chemical

• Perception Channels
• visual
• chemical

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)

• Primary Diet
• herbivore
  • folivore

• 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

• Known Predators

  • Formicidae
  • Reduviidae
  • Nabidae
  • Carabidae
  • Spiders

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)

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.

• IUCN Red List

  Not Evaluated No special status

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Contributors

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

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.