Arocatus melanocephalus | INFORMATION

Scientific Classification

This scientific name is not yet recognized in our classification database.
Rank	Scientific Name
Species	Arocatus melanocephalus

By Avery Gibson

Geographic Range

Arocatus melanocephalus , also known as elm seed bugs, is thought to be native to Europe. These bugs have also been reported in China, the middle east, the United States, and Canada. The first appearance of elm seed bugs in North America was in the early 2010's.

In 1998, prior to the rapid spread of elm seed bugs, the distribution of elm seeds bugs was reported. This reported distribution was in central and southern Europe, between the 52nd and 37th parallels, from France to western Kazakhstan.

Habitat

Elm seed bugs primarily live on elm trees. They have also been reported on other types of trees and frequently invade urban buildings during summer, particularly ones near elm trees. Warmer temperatures may be beneficial for elm seed bugs, although they are intolerant of temperatures greater than 30 degrees Celsius (Maistrello et al., 2006).

Habitat Regions
temperate

Terrestrial Biomes
forest

Other Habitat Features
urban

Physical Description

Adult elm seed bugs are about 6.5-7 mm long and have oval-shaped bodies. Their underside and abdomen are red, while the rest of their body is dark brown or black. They have wings that cross over on the top of their back. Half of the wing is black, and the other half is red brown. This coloration creates an upside-down black triangle at the top of the back and two sideways red-brown triangles in the middle of the back. Nymphs look similar to adults but are smaller, rounder, and more brightly colored.

Development

Elm seed bugs develop via incomplete metamorphosis. They have three life stages: egg, nymph, and adult. Eggs are laid inside of fruits in the beginning of spring and hatch soon after. These nymphs molt five times to adults. This process takes approximately 4-6 weeks. Adults start appearing in late May, and by June, almost all elm seed bugs reach adulthood. Adults overwinter underneath tree bark and in cracks. In March, adults emerge from their overwintering places and move to a host tree to reproduce.

Development - Life Cycle
metamorphosis
diapause

Reproduction

Elm seed bugs mate once per year in March or April. Mating occurs in the fruits of the tree. Not much research has been done on elm seed bug mating systems. Other insects in the same family, Lygaeidae, are known to be promiscuous, meaning that both males and females have multiple mates.

Mating System
polygynandrous (promiscuous)

Elm seed bugs mate and lay their eggs inside of elm flowers around the time they bloom, in May. They produce one generation each year.

Not much research has been done on the parental investment of elm seed bugs. There is no evidence that any insects in the same family, Lygaeidae, invest in their offspring. The only way in which elm seed bugs are currently known to care for their offspring is by laying their eggs in places that will benefit their offspring when they hatch.

Parental Investment
no parental involvement

Lifespan/Longevity

There is insufficient research to determine the lifespan of elm seed bugs. They can life for at least one year, as that it the amount of time it takes for them to reproduce.

Behavior

When the elm seed bug eggs hatch, the nymphs feed on an elm seed until the seed drops from the tree. Afterwards, they can be found crawling around on the trunk of the tree and in nearby areas. Nymphs may remain on the host tree or crawl to another tree or structure. Adult elm seed bugs can travel by flying and crawling. During summer, adults are likely to be found inside and around human houses, though some remain on trees.

Elm seed bugs overwinter as adults underneath tree bark and inside of the tree's cracks and crevices. In the summer, elm seed bugs have been observed gathering in small groups underneath leaves and inside of cracks in the bark of elm trees. While in these groups, they have reduced activity and do not feed, which suggests that they may have entered a period of summer diapause known as aestivation.

When elm seed bugs feel threatened or are harmed, they emit an unpleasant odor.

Key Behaviors
arboreal
flies
motile
hibernation
aestivation
social

Communication and Perception

Elm seeds bug communicate with chemical signals called pheromones. They also have sensory organs that detect these pheromones. Additionally, elm seed bugs have eyes called ocelli to percieve the world visually.

Communication Channels
chemical

Other Communication Modes
pheromones

Perception Channels
visual
chemical

Food Habits

Elm seed bugs are herbivores that feed primarily on the sap of elm seeds and leaves ( Ulmus spp.). They have also been observed feeding on other trees, such as oak ( Quercus ) and linden ( Tilia ). They feed by sticking their long and mouthparts into the seed or leaf and sucking. In North America, it has been reported that their feeding habits have little to no negative effect on the tree. In Europe, reports show that elm seed bugs cause significant damage to the trees' leaves.

Primary Diet
herbivore
- eats sap or other plant foods

Plant Foods
sap or other plant fluids

Predation

The predators of elm seed bugs are currently unknown.

Ecosystem Roles

The ecosystem role of elm seed bugs is debated. They are either parasitic on or have a commensal relationship with elm trees. Currently, the predators of elm seed bugs have not been identified.

Ecosystem Impact
parasite

Species Used as Host

Elm trees ( Ulmus spp.)

Economic Importance for Humans: Positive

Elm seed bugs are a useful research subject for humans. By studying them, researchers can gain a better understanding of how climate change impacts insect populations. They can also use them to develop more efficient methods to control household pests.

Positive Impacts
research and education

Economic Importance for Humans: Negative

Elm seed bugs are household pests. Although they are not harmful to humans in any way, they are a nuisance in urban buildings and emit an off-putting, bitter-almond-like odor. They also cause some management costs to businesses and homeowners. Elm seed bugs most commonly invade when outside temperatures are high and relative humidity is low.

Negative Impacts
household pest

Conservation Status

Elm seed bugs have no conservation status.

Other Comments

Elm seed bugs are also known as tuxedo seed bugs.

There was little research done on elm seed bugs prior to approximately the year 2000. Around this time, massive numbers of elm seed bugs were suddenly reported invading human homes in Italy. In following years, these bugs spread throughout Europe as well as overseas. Elm seed bugs were first reported in the United States in the early 2010's.

Additional Links

Encyclopedia of Life

Contributors

Avery Gibson (author), Colorado State University.

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

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

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

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

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

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

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

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

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).

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

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

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.

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.

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

seasonal breeding: breeding is confined to a particular season

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

fertilization: union of egg and spermatozoan

internal fertilization: fertilization takes place within the female's body

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

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

motile: having the capacity to move from one place to another.

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.

social: associates with others of its species; forms social groups.

chemical: uses smells or other chemicals to communicate

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

visual: uses sight to communicate

chemical: uses smells or other chemicals to communicate

parasite: an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death

herbivore: An animal that eats mainly plants or parts of plants.

References

Acheampong, S., W. Strong, M. Schwartz, R. Higgins, M. Thurston, E. Walker, J. Roberts. 2016. First Canadian records for two invasive seed-feeding bugs, Arocatus melanocephalus (Fabricius, 1798) and Raglius alboacuminatus (Goeze, 1778), and a range extension for a third species, Rhyparochromus vulgaris (Schilling, 1829) (Hemiptera: Heteroptera). Entomological Society of British Columbia , Vol. 113: 74-78.

Bianchi, Z., O. Štepanovičová. 2003. Some notes on the occurrence of Arocatus genus (Heteroptera, Lygeidae) in Slovakia. Folia faunistica Slovaca , 8: 75-77.

Burdfield-Steel, E., D. Shuker. 2014. Mate-guarding in a promiscuous insect: species discrimination influences context-dependent behaviour. Evolutionary Ecology , 28: 1031-1042. Accessed September 24, 2023 at https://doi.org/10.1007/s10682-014-9726-7 .

Burdfield-Steel, E., D. Shuker. 2014. The evolutionary ecology of the Lygaeidae. Evolutionary Ecology , 4(11): 2278-2301. Accessed September 24, 2023 at https://doi.org/10.1002/ece3.1093 .

Davis, R. 2018. "Elm Seed Bug (Arocatus melanocephalus)" (On-line). Extension Utah Pests. Accessed August 14, 2023 at https://extension.usu.edu/pests/research/elm-seed-bug .

Ferracini, C., A. Alma. 2008. Arocatus melanocephalus: a hemipteran pest on elm in the urban environment. Bulletin of Insectology , 61(1): 193-194.

Meistrello, L., L. Lombroso, E. Pedroni, A. Reggiani, S. Vanin. 2006. Summer raids of Arocatus melanocephalus (Heteroptera, Lygaeidae) in urban buildings in Northern Italy: Is climate change to blame?. Journal of Thermal Biology , 31(8): 594-598. Accessed September 06, 2023 at https://doi.org/10.1016/j.jtherbio.2006.08.002 .

Mulder, J. 2021. Mass invasion of Elm seed bugs Arocatus melanocephalus (Fabricus, 1798) (Hemitpera Lygaeidae) in apartments in the Netherlands. Biodiversity Journal , 12(1): 229-230. Accessed September 06, 2023 at https://doi.org/10.31396/Biodiv.Jour.2021.12.1.229.230 .

Myrkassimova, A., S. Demeuov, K. Kulanbay. 2022. Phenology of elm seed bug (Arocatus melanocephalus) in Almaty City of southeastern Kazakhstan. SABRAO Journal of Breeding and Genetics , 54(1): 193-200. Accessed September 12, 2023 at http://doi.org/10.54910/sabrao2022.54.1.18 .

Pedroni, E., L. Maistrello, P. Boldrini, A. Sbrenna, G. Sbrenna. 2008. Metathoracic scent glands in female adults of Arocatus melanocephalus. Bulletin of Insectology , 61(1): 173-175.