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Harpalus affinis

By Amy Bagby

Geographic Range

Harpalus affinis, (Harpalus as in a Greek reference to "greed," and affinis meaning "akin to" in Latin) is a species native to Europe (Bug Guide, 2015). Their range reaches across the Northwestern side of the continent, with a scattering of occurrences spreading eastwards towards Kazakhstan. These beetles can also be found where they have been introduced in the Northeast corner of the United States. There are some occurrences on the west coast of the continent as well, but they are infrequent (Lorenz, 2021). Lastly, these beetles are often spotted in their introduced habitat of Australia and New Zealand (Lövei and McCambridge, 2002). ("Genus Harpalus", 2015; Lorenz, 2021; Lövei and McCambridge, 2002)

Habitat

Harpalus affinis can live on a wide range of substrate types, given the right conditions. These carabids require coarse soils that drain well, such as dry grasslands, cropland, and sand dunes akin to those near coasts. Despite the many types of prospective living areas, they are rarely found very far inland (Anderson et al, 2000). (Anderson, et al., 2000; Lorenz, 2021)

  • Range elevation
    0 to 769 m
    0.00 to 2522.97 ft

Physical Description

These ground beetles are on the smaller side with an average body length of around a centimeter. They are black and metallic in color, however the females are usually less shiny than the males (Anderson et al., 2000). In addition, their shine usually comes in hues of bronze and teal (Keinath et al., 2020). (Anderson, et al., 2000; Lorenz, 2021)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • male more colorful
  • Range length
    8.5 to 12 mm
    0.33 to 0.47 in

Development

Harpalus affinis undergo holometabolous development, which is more commonly known as complete metamorphosis. As a result, they experience an egg, larval, pupal, and adult stage. The larvae will molt multiple times before pupating (Drnevich, 2009). (Drnevich, 2009)

Reproduction

There are no known mating systems described for H. affinis.

Although there is little study surrounding this topic, it has been found that females typically carry anywhere from one to seven eggs at a time during the breeding season. It is unclear if this will be all of the eggs they will lay annually (Sunderland et al., 1995). Females that have recently emerged as adults, as well as older females that have overwintered, will both breed in the spring and summer and complete laying eggs by the fall (Lövei and McCambridge, 2002). (Lövei and McCambridge, 2002; Sunderland, et al., 1995)

  • Breeding interval
    These beetles breeds annually.
  • Breeding season
    Harpalus affinis will breed in the spring and summer months.

No form of parental investment has been described for H. affinis.

  • Parental Investment
  • no parental involvement

Lifespan/Longevity

Not much is known about the lifespan of these carabids in the wild, although it is expected to be potentially longer than in a lab setting. In captivity, lifespans were shown to be closer to two years. These did differ by sex and the time of year the insect metamorphosed. Summer males lived longer than summer females, and spring females lived longer than spring males. Average lifespans for both seasons were between around 270 and 290 days (Lövei and McCambridge, 2002). (Lövei and McCambridge, 2002)

  • Range lifespan
    Status: captivity
    113 to 655 days
  • Typical lifespan
    Status: captivity
    267 to 290 days

Behavior

Harpalus affinis are flightless, solitary predators that are built for quickness on the ground. Larvae of the species are able to move, but given that they require much nutrition and are relatively poorly defended, they typically stay in one place. Overall, they do not gather in groups or pairs often, if at all - aside from mating (Lövei and Sunderland, 1996). (Lövei and Sunderland, 1996)

Home Range

Their is no specific home range attributed to Harpalus affinis

Communication and Perception

Though not much research has focused on Harpalus affinis outside of diet and reproduction, most insects tend to communicate through multiple mediums. Visual cues allow these beetles to watch for behaviors from predators, prey, and potential mates. They also help the insects to identify vital lighting cues. Separately, thigmotaxis lets them communicate through touch with their antennae (a very strong sensory organ). Antennae also help with chemical cues like pheromones that may be incoming from the same species or others. Lastly, insects (including H affinis) possess small spines - or hairs - around their bodies called setae, which help them sense vibrations from movement and sound (NC State, 2015). (NC State, 2015)

Food Habits

Despite its status as an omnivore, Harpalus affinis are primarily vegetarian. These ground beetles have a penchant for seeds from species such as chickweed, dandelion, crabgrass, knotweed, red clover, and strawberry. They will also eat pollen and anther stalks from flowering plants. The carnivorous aspect of their diets consists of various small organisms. Creatures such as spiders, other insects, and worms are excellent prey items for these beetles (Sunderland, 1995). Also notable is that H. affinis are important natural predators of bird cherry-oat aphids (Rhopalosiphum padi) and apple maggots (Rhagoletis pomonella) (CABI, 2021). These carabids are also known to be ovivores and detritivores (Sunderland, 1995). (CABI, 2021; Sunderland, et al., 1995)

Males of the species will sometimes be found to have not fed recently if at all. This could be because they simply do not require the same amount of energy that females do. A male's role is to mate and mate alone, whereas the females needs energy for egg nutrition and laying. As a result, they will be more likely to have a full gut (Sunderland 1995). (Sunderland, et al., 1995)

  • Animal Foods
  • eggs
  • insects
  • terrestrial non-insect arthropods
  • terrestrial worms
  • Plant Foods
  • seeds, grains, and nuts
  • pollen
  • flowers

Predation

The main anti-predator adaptation seen in Harpalus affinis is camouflage. All beetles of the species are a dark black with metallic tones. Males have green notes, whereas females are more bronze or metallic green. Areas where pollution is high see more bronze beetles. The opposite conditions give rise to more green beetles. A possible explanation for these color morphs could be that the haze of pollution appears more brown than clear, so bronze beetles would blend in more effectively (Keinath, 2021). (Keinath, et al., 2020)

  • Anti-predator Adaptations
  • cryptic
  • Known Predators
    • No specific known predators have been described to feed on H. affinis

Ecosystem Roles

These beetles are effective natural predators of apple maggots (Rhagoletis pomonella) and bird cherry-oat aphids (Rhopalosiphum padi) (CABI, 2021). Additionally, they keep levels of certain weed species like the dandelion (Taraxacum officinale) in control (Sunderland, 1995). (CABI, 2021; Sunderland, et al., 1995)

Species Used as Host
  • This relationship has not been described for H. affinis.
Mutualist Species
  • This relationship has not been described for H. affinis.
Commensal/Parasitic Species
  • This relationship has not been described for H. affinis.

Economic Importance for Humans: Positive

Harpalus affinis have some potential as a biological control agents of apple maggots (Rhagoletis pomonella) and bird cherry-oat aphids (Rhopalosiphum padi) since they are their natural predators (CABI, 2021). They are also a good control species for codling moths (Cydia pomonella). Additionally, they keep weed species that humans find unsightly, like dandelions (Taraxacum officinale), under control (Sunderland, 1995). (CABI, 2021; Sunderland, et al., 1995)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

There are no known adverse effects of H. affinis on humans.

Conservation Status

Harpalus affinis have no special conservation status associated with them, as they are not threatened where they are found.

Contributors

Amy Bagby (author), Colorado State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

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

Palearctic

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

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

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.

detritus

particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).

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.

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.

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

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.

holarctic

a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.

World Map

Found in northern North America and northern Europe or Asia.

insectivore

An animal that eats mainly insects or spiders.

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.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

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

pheromones

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

sexual

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

solitary

lives alone

tactile

uses touch to communicate

taiga

Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.

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.

tropical

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

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

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

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

vibrations

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

visual

uses sight to communicate

References

2015. "Genus Harpalus" (On-line). Bug Guide. Accessed September 30, 2021 at https://bugguide.net/node/view/7306.

Anderson, R., D. McFerran, A. Cameron. 2000. The Ground Beetles of Northern Ireland. Belfast: 1st. Ed. Pub. Ulster Museum.

CABI, 2021. "CAB International" (On-line). Harpalus affinis. In: Invasive Species Compendium. Accessed July 27, 2021 at https://www.cabi.org/isc/datasheet/26529.

Drnevich, J. 2009. "Beetle Life Cycle" (On-line). ASU - Ask a Biologist. Accessed July 23, 2021 at https://askabiologist.asu.edu/life-cycle.

Keinath, S., J. Frisch, J. Müller, F. Mayer, M. Rödel. 2020. Spatio-Temporal Color Differences Between Urban and Rural Populations of a Ground Beetle During the Last 100 Years. Frontiers in Ecology and Evolution, 7: 1-10. Accessed July 21, 2021 at https://www.researchgate.net/figure/Photographs-of-the-three-Harpalus-affinis-color-morphs-green-bronze-and-mixed_fig2_338764285.

Lorenz, W. 2021. "Harpalus affinis (Schrank, 1781)" (On-line). Global Biodiversity Information Facility. Accessed July 22, 2021 at https://www.gbif.org/species/9750962.

Lövei, G., M. McCambridge. 2002. Adult mortality and minimum lifespan of the ground beetle Harpalus affinis (Coleoptera: Carabidae) in New Zealand. New Zealand Journal of Zoology, 29: 1-4. Accessed July 23, 2021 at https://www.tandfonline.com/doi/abs/10.1080/03014223.2002.9518283.

Lövei, G., K. Sunderland. 1996. Ecology and Behavior of Ground Beetles (Coleoptera: Carabidae). Annual Review of Entomology, 41: 231-256. Accessed July 26, 2021 at https://www.originalwisdom.com/wp-content/uploads/bsk-pdf-manager/2019/04/Lovei-and-Sunderland_1996_ECOLOGY-AND-BEHAVIOR-OF-GROUND-BEETLES.pdf.

NC State, 2015. "Insect Communication" (On-line). NC State Agriculture and Life Sciences. Accessed July 20, 2021 at https://genent.cals.ncsu.edu/bug-bytes/communication/.

Sunderland, K., G. Lövei, J. Fenlon. 1995. Diets and Reproductive Phenologies of the Introduced Ground Beetles Harpalus aflnis and Clivina australasiae (Coleoptera : Carabidae) in New Zealand. Australian Journal of Zoology, 43 (1): 39-50. Accessed July 25, 2021 at https://colostate.primo.exlibrisgroup.com/discovery/fulldisplay?docid=cdi_csiro_primary_zo9950039_htm&context=PC&vid=01COLSU_INST:01COLSU&lang=en&search_scope=MyCampus_FC_CI_PU_P&adaptor=Primo%20Central&tab=Everything&query=any,contains,harpalus%20affinis.

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