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Umbonia

By Amanda Sieps

Diversity

The genus Umbonia, comprised of four known species, consists of plant-sucking insects. These insects are also known as "thorn bugs" due to their thorn-like appearance, resulting from the growth of their pronotum extending back over their abdomen. This particular genera has one prominent "horn" curving upward and two smaller "horns" on either side of the head. The adult's body size can be between 9mm-14 mm. These insects are often green, light blue, or yellow in overall coloration with striping being yellow-orange, dark green, or red. Umbonia are unique for their social behavior and brood care. They can be considered pests when large groupings of them congregate on tropical plants. Umbonia can be found almost year-round from southeastern United States all the way to Brazil. (Alvarez and Deitz, 2008; Anvik, 2012; DiTerlizzi, 2015; "Thorn bug", 2021; "Umbonia crassicornis", 2022; Wallace and Deitz, 2011)

Geographic Range

Umbonia are found in humid, tropical areas of the Neotropical and Nearctic regions of the world (i.e. southern Florida, Central America, Brazil), but over the last decade have become more prominent in the Nearctic region due to global warming. (Hernick, 2011; "Thorn bug", 2021; Wallace and Deitz, 2011)

Habitat

Umbonia thrive in warm, tropical climates in low elevations. They are regularly found in southern Florida, Mexico, and throughout Central and South America. They live off of host plants found in these areas such as acacia, calliandra, mimosa, and inga, congregating around their branches and stems. Reproduction, brood care, and foraging all take place on host plants. (Buckley, 1987; Cocroft, 1999a; Hernick, 2011; Martorell and García-Tudurí, 1973; Müller, 1874; "Thorn bug", 2021)

Systematic and Taxonomic History

Umbonia was originally called Physoplia by Amyot and Serville in 1843 but was given its modern name by Burmeister in 1835 due to a violation of ICZN (International Commission on Zoological Nomenclature). Based on maternal care studies and pronotum structure, Umbonia is more closely related to the genus Platycotis, another group of treehoppers within the tribe Hoplophorionini. Genera within this tribe are characterized by their unique kicking anti-predator defense and geographic region ranging from Canada to Chile. Umbonia species are one of the most derived genera of the family Membracidae. (Creão-Duarte and Sakakibara, 1996; Dietrich, 2004; DiTerlizzi, 2015; Lin, et al., 2004; McKamey, 2010; McKamey and Deitz, 1996; "OneZoom: Umbonia", 2022; Wallace and Deitz, 2011)

  • Synonyms
    • Physoplia
  • Synapomorphies
    • Protect themselves/offspring against predators with kicking defenses
    • Create extra-ovipositional punctures in the host plant, which nymphs feed from

Physical Description

Umbonia treehoppers generally grow to roughly half an inch (about 10 mm). They vary in color and patterns, but are most often a green or light blue color with red, brown, and/or green markings. They are most notable for their pronotum, which grows perpendicularly to their body in a thorn-like shape so to be mistaken for a thorn on a plant. Males and females are the same size (with a few exceptions in some species where females are smaller) and pattern, but are easily told apart by the shape of the pronotum growth on their backside. Females' are slightly longer and flatten out towards the tip of the thorn to a blunt end. Males' stay pointed and are usually shorter in comparison. Nymphs look like smaller versions of the parents, but with more prominently pointed "side horns" and no wings. Because adults can be either bright green or light blue, species are often mistaken with each other. There is no seasonal variation, and they are active year-round. (Adachi, et al., 2020; Cocroft, 1999b; Mead, 2014; "Umbonia crassicornis", 2022; Wallace and Deitz, 2011)

  • Sexual Dimorphism
  • sexes shaped differently

Development

Umbonia displays incomplete metamorphosis or are hemimetabolous, meaning there is no pupal stage in their growth from larva to adult. After mating, females lay their eggs and it takes about 14-20 days for them to hatch. After hatching, the nymphs continue to grow for the next four weeks and complete five molts before they are at the adult stage. Each molt allows the nymphs to become larger in size and have more developed wings. (Adachi, et al., 2020; Cocroft, 1999a; Cocroft, 1999b; Dietrich, 2004; "Thorn bug", 2021; "Umbonia crassicornis", 2022)

Reproduction

Males within Umbonia must compete for a female, as females often only mate once in their lifetime. Males and females are often seen in congregations together on plants, but there is no visible display of males warding off others from their female(s) of choice. Females have been seen to choose males based on age, wherein older males are preferred. Males will attract females by making calls or clicks using their abdominal muscles. While males spend their time hopping from plant to plant in search of mating opportunities, females stay together to help protect and raise their young. (Cocroft, 1999a; De Luca, 2007; "Umbonia crassicornis", 2022; Wood and Dowell, 1985)

After mating, females will lay about 100 eggs into plants' stems or leaves and stay with the clutch until the hatched nymphs fully mature. Eggs hatch about 20 days after laying, and out of the 100-count egg clutch, only 15-20 nymphs will survive. Although females only mate once in their lifetime, four generations are produced every year. Depending on the host plant, a large congregation of Umbonia species/individuals can create a resource shortage; therefore, when the nymphs have matured, they can be much smaller than average. This does not affect females, but smaller males often have a difficult time finding mates. (Cocroft, 1999a; De Luca, 2007; "Umbonia crassicornis", 2022; Wood and Dowell, 1985)

Umbonia females exhibit maternal care for their young. Males are uninvolved after fertilization. Females do not hunt or teach their young skills, but they do protect their egg clutch until her offspring are all mature adults. If the mother dies or is unable to protect her young before they are mature, another female can adopt the clutch. Nymphs only communicate with their caretaker when they sense a threat nearby by creating vibrations through the host plant. The nymphs must work together to create these vibrations, otherwise the female will ignore the call. Once the nymphs have matured, they often leave the host plant in search of a new host and/or mating opportunities to avoid inbreeding. (Anvik, 2012; Cocroft, 1999a; Cocroft, 1999b; Cocroft, et al., 2000; De Luca, 2007; Lin, et al., 2004; "Umbonia crassicornis", 2022; Wood, 1976; Wood, 1977; Wood and Dowell, 1985)

  • Parental Investment
  • female parental care
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • female
  • pre-weaning/fledging
    • protecting
      • female
  • pre-independence
    • protecting
      • female

Lifespan/Longevity

Umbonia individuals in the wild only live to be a few months old, just long enough to develop, reproduce, and raise young (if they are a female). Ultimately, lifespan is affected by how many resources are available at time of hatching through adulthood. (De Luca, 2007; Hernick, 2011; Mead, 2014; Wood and Dowell, 1985)

Behavior

Umbonia consists of social species that often remain in the same general area throughout their lifespan. Males are more solitary than females but are still in congregations when trying to attract a female. Females often stay together to assist in raising young. Males communicate with females via their abdominal muscles for mating purposes, and nymphs communicate with females through plants for alerting purposes.

Hence their common name "treehoppers," this genus is well-known for the species' odd way of jumping from plant to plant, often doing a summersault mid-air in the process. They can also fly, which is more efficient than jumping, but with age they lose this ability. (Buckley, 1987; Cocroft, 1999a; Hernick, 2011; Martorell and García-Tudurí, 1973; Mead, 2014; "Umbonia crassicornis", 2022; Wood, 1977)

Communication and Perception

Treehoppers rely heavily on communication through vibration detection. They have two large, compound eyes for focusing images and ocelli to distinguish sunlight from shadow, but vibrations have proven to be more reliable. The calls and clicks males make when attracting a female create vibrations, and nymphs communicate using vibrations within the plants they occupy.

Since their body is in the shape of a thorn on the stem of a plant, these species utilize camouflage to hide from predators. (Buckley, 1987; Cocroft, 1999b; Cocroft, et al., 2000; Wood, 1976)

Food Habits

Treehoppers are herbivores. They have piercing-sucking mouthparts that assist in stabbing soft plant stems and sucking the sappy substance out of them. Umbonia species have a wide array of plant hosts, including but not limited to tamarinds (Tamarindus indica), bottlebrushes (Callistemon sp.), Madras thornes (Pilhecellobium dulce), and silk plants (Albizzia lebbeck). (Alvarez and Deitz, 2008; Buckley, 1987; Mead, 2014; "Thorn bug", 2021; Wallace and Deitz, 2011)

Predation

Umbonia species' thorn-like body plans and camouflaging colorations protect them from predators. They also create a chemical repellent that is passed from parents to offspring which makes them distasteful to predators.

Treehoppers are prey to various birds, lizards, spiders, and assassin bugs species. Their primary threat, however, are wasps. (Cocroft, 1999a; Cocroft, 1999b; Dietrich, 2004; Hernick, 2011; Reinhard, 1925; "Umbonia crassicornis", 2022; Wallace and Deitz, 2011)

  • Anti-predator Adaptations
  • mimic
  • cryptic

Ecosystem Roles

Umbonia species are a food source for many insectivores, both vertebrates and invertebrates. Since treehoppers are sap-sucking herbivores, they are responsible for killing plants when in large enough congregations. They have been known to disrupt pollinators, but have the ability to be pollinators themselves, although it is very uncommon. (Buckley, 1987; Dietrich, 2004; Hernick, 2011; Martorell and García-Tudurí, 1973; McKamey and Deitz, 1996; Mead, 2014; Müller, 1874; Reinhard, 1925; "Treehoppers", 2022; Wood and Dowell, 1985)

Species Used as Host
  • Tamarindus indica
  • Pilhecellobium dulce
  • Albizzia lebbeck
  • Acacia centralis
  • Enterolobium cyclocarpum
  • Calliandra bijuca
  • Zygia palmanum
  • Inga punctata
Commensal/Parasitic Species

Economic Importance for Humans: Positive

Treehoppers are a very important prey type for various bird, lizard, and insect species. Although they do not positively affect the human economy directly, they indirectly do by serving as a food source for other animals that do affect humans. (Buckley, 1987; Dietrich, 2004; Ibarra-Isassi and Oliveira, 2018; Martorell and García-Tudurí, 1973; "Thorn bug", 2021; "Treehoppers", 2022; "Umbonia crassicornis", 2022; Wood and Dowell, 1985)

  • Positive Impacts
  • food
  • research and education

Economic Importance for Humans: Negative

In some regions, Umbonia species can be considered a pest. Since they are widespread and spend their lives on plant stems eating and reproducing, large enough congregations can kill plant hosts. They are easy to get rid of with conventional pesticides if there are too many in one area. Otherwise, treehoppers do not bite or sting, making them relatively harmless. (Buckley, 1987; Dietrich, 2004; Ibarra-Isassi and Oliveira, 2018; Martorell and García-Tudurí, 1973; "Thorn bug", 2021; "Treehoppers", 2022; Wood and Dowell, 1985)

  • Negative Impacts
  • crop pest

Conservation Status

There is no known conservation status for Umbonia, but Umbonia species do not seem to be significantly threatened in any manner. (Dietrich, 2004; McKamey, 2010; "Umbonia crassicornis", 2022)

  • IUCN Red List [Link]
    Not Evaluated

Other Comments

There is not a lot of available taxonomic publications relevant to this genus. Most studies that revolve around Umbonia species focus on the species' unique parental behaviors and their impacts as a pest for plant species. Genetic taxonomic hypotheses are based primarily on behavioral genetics relating to parental investment.

Contributors

Amanda Sieps (author), Colorado State University, Audrey Bowman (editor), Colorado State University, Sydney Collins (editor), Colorado State University.

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

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

arboreal

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

cooperative breeder

helpers provide assistance in raising young that are not their own

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.

diurnal
  1. active during the day, 2. lasting for one day.
female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

food

A substance that provides both nutrients and energy to a living thing.

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.

internal fertilization

fertilization takes place within the female's body

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

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.

polygynous

having more than one female as a mate at one time

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

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).

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

vibrations

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

visual

uses sight to communicate

year-round breeding

breeding takes place throughout the year

References

2022. "OneZoom: Umbonia" (On-line). OneZoom Tree of Life. Accessed March 23, 2022 at http://www.onezoom.org/life/@Umbonia=788541?img=best_any&anim=flight#x490,y213,w0.8179.

2021. "Thorn bug" (On-line). Forest Pest Insects in North America: a Photographic Guide. Accessed January 28, 2022 at https://www.forestpests.org/vd/58417.html.

2022. "Treehoppers" (On-line). Missouri Department of Conservation. Accessed March 02, 2022 at https://mdc.mo.gov/discover-nature/field-guide/treehoppers.

2022. "Umbonia crassicornis" (On-line). Wikipedia. Accessed February 09, 2022 at https://en.wikipedia.org/wiki/Umbonia_crassicornis.

Adachi, H., K. Matsuda, K. Nishida, P. Hanson, S. Kondo, H. Gotoh. 2020. Structure and development of the complex helmet of treehoppers (Insecta: Hemiptera: Membracidae). Zoological Letters, Volume 6, Article 3: 1. Accessed February 09, 2022 at https://doi.org/10.1186/s40851-020-00155-7.

Alvarez, P., L. Deitz. 2008. "Treehoppers" (On-line). DrMetcalf: a resource on cicadas, leafhoppers, planthoppers, spittlebugs, and treehoppers. Accessed January 28, 2022 at https://www.lib.ncsu.edu/specialcollections/digital/metcalf/treehoppers.html.

Anvik, S. 2012. Maternal Defensive Behavior Of Umbonia Ataliba Treehoppers. Monteverde Institute: Monteverde Institute. Accessed January 28, 2022 at https://digital.lib.usf.edu/?m39.357.

Buckley, R. 1987. Interactions Involving Plants, Homoptera, and Ants. Annual Review of Ecology and Systematics, Volume 18: 111-135. Accessed January 28, 2022 at https://www.jstor.org/stable/2097127.

Cocroft, R. 1999. Offspring-Parent Communication in a Subsocial Treehopper (Hemiptera: Membracidae: Umbonia crassicornis). Behaviour, Volume 136: 1-21. Accessed January 28, 2022 at https://www.jstor.org/stable/4535591.

Cocroft, R., T. Tieu, R. Hoy, R. Miles. 2000. Directionality in the mechanical response to substrate vibration in a treehopper (Hemiptera: Membracidae: Umbonia crassicornis). Journal of Comparative Physiology A, Volume 186: 695-705. Accessed January 28, 2022 at https://doi.org/10.1007/s003590000123.

Cocroft, R. 1999. "Thornbug to Thornbug" (On-line). Natural History. Accessed January 28, 2022 at https://www.naturalhistorymag.com/picks-from-the-past/12497/thornbug-to-thornbug.

Creão-Duarte, A., A. Sakakibara. 1996. Revision of the genus Umbonia Burmeister (Homoptera, Membracidae, Membracinae, Hoplophorionini). Brazilian Journal of Zoology, Volume 13, Issue 4: 973-994. Accessed January 28, 2022 at https://doi.org/10.1590/S0101-81751996000400018.

De Luca, P. 2007. "Age effects on reproductive behavior in the treehopper umbonia crassiscornis (Hemipera: membracidae)" (On-line pdf). MOspace. Accessed February 23, 2022 at https://doi.org/10.32469/10355/4867.

DiTerlizzi, T. 2015. "Genus Umbonia" (On-line). BugGuide.Net. Accessed January 28, 2022 at https://bugguide.net/node/view/4797.

Dietrich, C. 2004. Treehoppers (Hemiptera: Membracidae). Encyclopedia of Entomology, Volume 1: 220. Accessed March 02, 2022 at https://doi.org/10.1007/0-306-48380-7_4380.

Hernick, C. 2011. Distribution And Host Species Ranges Of Umbonia Ataliba And Umbonia Crassicornis And The Potential For Interspecific Competition. Monteverde Institute: Monteverde Institute. Accessed January 28, 2022 at https://digital.lib.usf.edu/?M39.80.

Ibarra-Isassi, J., P. Oliveira. 2018. Indirect effects of mutualism: ant–treehopper associations deter pollinators and reduce reproduction in a tropical shrub. Oecologia, Volume 186: 691–701. Accessed March 02, 2022 at https://doi.org/10.1007/s00442-017-4045-7.

Lin, C., B. Danforth, T. Wood. 2004. Molecular Phylogenetics and Evolution of Maternal Care in Membracine Treehoppers. Systematic Biology, Volume 53, Issue 3: 400-421. Accessed January 28, 2022 at https://doi.org/10.1080/10635150490445869.

Martorell, L., J. García-Tudurí. 1973. Notes on the Accidental Introduction of Umbonia crassicornis (Amyot and Serville)— (Hemiptera: Membracidae) into Puerto Rico and its Control. The Journal of Agriculture of the University of Puerto Rico, Volume 57: 307-313. Accessed January 28, 2022 at https://doi.org/10.46429/jaupr.v57i4.10729.

McKamey, S. 2010. "Catalouge of Life" (On-line). Membracoidea of the World Database. Accessed February 01, 2022 at https://doi.org/10.48580/d4tn-3bt.

McKamey, S., L. Deitz. 1996. Generic revision of the New World tribe Hoplophorionini (Hemiptera: Membracidae: Membracinae). Systematic Entomology, Volume 21, Issue 4: 295-342. Accessed February 16, 2022 at https://doi.org/10.1111/j.1365-3113.1996.tb00602.x.

Mead, F. 2014. "Thorn bug" (On-line). Featured Creatures. Accessed January 28, 2022 at https://entnemdept.ufl.edu/creatures/orn/thorn_bug.htm.

Müller, H. 1874. Larvæ of Membracis Serving as Milk-Cattle to a Brazilian Species of Bee. Nature, Volume 10: 31-32. Accessed January 28, 2022 at https://doi.org/10.1038/010031a0.

Reinhard, E. 1925. The wasp Hoplisus costalis, a hunter of treehoppers. Journal of the Washington Academy of Sciences, Volume 15, Issue 5: 107-110. Accessed March 02, 2022 at https://www.jstor.org/stable/24527290.

Wallace, M., L. Deitz. 2011. "Umbonia Burmeister, 1835" (On-line). Treehoppers: Aetalionidae, Melizoderidae, and Membracidae (Hemiptera). Accessed February 09, 2022 at http://treehoppers.insectmuseum.org/public/public_content/show/11914.

Wood, T. 1976. Alarm Behavior of Brooding Female Umbonia crassicornis (Homoptera: Membracidae). Annals of the Entomological Society of America, Volume 69, Issue 2: 340-344. Accessed January 28, 2022 at https://doi.org/10.1093/aesa/69.2.340.

Wood, T. 1977. Defense in Umbonia crassicornis: Role of the Pronotum and Adult Aggregations (Homoptera: Membracidae). Annals of the Entomological Society of America, Volume 70, Issue 4: 524-528. Accessed January 28, 2022 at https://doi.org/10.1093/aesa/70.4.524.

Wood, T., R. Dowell. 1985. Reproductive Behavior and Dispersal in Umbonia crassicornis (Homoptera: Membracidae). The Florida Entomologist, Volume 68, Issue 1: 151-158. Accessed February 23, 2022 at https://doi.org/3494339.

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Classification

  • This scientific name is not yet recognized in our classification database.