Like many insects, Harmonia axyridis communicates via vision and chemical/sensory signals through the release of various pheromones. Many pheromones are used for mating signals, as is the case with many insects. They also use these pheromones to detect other individuals for congregation and hibernation during the winter months. While researchers have found the effects that these pheromones have on behaviors, no research has been done regarding their identification. One identified pheromone, harmonine, is used for defense against predators. Harmonine is produced when attacked and is secreted by reflex bleeding from tarsal joints. Prey are generally found using sight or olfactory detection.
Communication Channels: visual ; chemical
Other Communication Modes: pheromones
Perception Channels: visual ; chemical
Harmonia axyridis has no special conservation status.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Harmonia axyridis is holometabolous, progressing from egg through four larval instars, to pupa and then adult. The mean duration of each immature stage is as follows: egg - 2.8 days, first instar - 2.5 days, second instar - 1.5 days, third instar - 1.8 days, fourth instar - 4.4 days, pupa - 4.5 days. The diet of the beetle is also known to have an effect on larval development and adult weight, as is temperature. Harmonia axyridis is generally considered bivoltine in much of the world, although up to four or five generations per year have been observed. Adults diapause over winter and start laying eggs in early spring, whenever average temperatures begin to reach 12°C.
Development - Life Cycle: metamorphosis ; diapause
Harmonia axyridis can cause significant economic damages on fruit crops, specifically grapes. This species will crawl inside them to feed and, when the grapes are harvested, will reflex bleed, causing an unpleasant taste. This taste can even be detected in wine if H. axyridis is accidentally incorporated during the wine-making process. It is also known to nip humans when handled.
Negative Impacts: injures humans (bites or stings); crop pest
Harmonia axyridis serves as a biological control species for many agricultural crops, as their main dietary sources are major agricultural pests. Their worldwide introduction is due to their intense predatory nature.
Positive Impacts: controls pest population
Harmonia axyridis is a host species for a variety of parasites and parasitoids, specifically from the orders Diptera (Strongygaster triangulifer) and Hymenoptera (Dinocampus coccinellae, Oomyzus scaposus, Homalotylus terminalis, Pachyneuron altiscuta). Mites of the genus Coccipolipus, protozoans (such as Microsporidia), nematodes, and fungal species (Hesperomyces virescens, Beauveria bassiana) may also use it as a host species.
Outside its native range, this species can create severe ecological pressures on indigenous Coccinellidae species as they out-compete and utilize resources efficiently. Some of the species most affected are Coccinella transversoguttata, Adalia bipunctata, and Coccinella novemnotata, although others have certainly experienced pressures, as well. They also prey on herbivorous pest species, which helps maintain plant species.
Commensal/Parasitic Species:
Harmonia axyridis is a predatory insectivore with chewing mandibles, primarily feeding on aphids and scale insects. They may also eat Thysanura species and mites. Butterfly and moth eggs may be eaten, as well. When other food sources are scarce, Harmonia axyridis has been known to eat other various Coccinellidae species. Occasionally, it may feed on grapes and similar fruits. Studies have seen that in some cases, this species will eat other sources, such as moths and pollen, but these are isolated incidences. Both adults and larvae of Harmonia axyridis will cannibalize eggs and smaller larvae.
Animal Foods: insects
Plant Foods: fruit; pollen
Primary Diet: carnivore (Insectivore )
Harmonia axyridis, the Asian lady beetle, is native to the Oriental region, found in China, ranging to the far south (Yunnan and Guangxi Provinces), Japan, Korea, Mongolia, and parts of the Palearctic region, from northern Kazakhstan, and eastern Russia west to the Altai Mountains and north to Siberia. It has been introduced to at least four other continents. Its range covers the majority of North America; it is found in Mexico, across the United States (excluding Alaska and Wyoming) and much of southern Canada. This species has been found widely across South America, excluding Amazonian areas. Its habitat ranges across southern and western Europe into Bosnia and Herzegovina and Romania, and recently was found in Tunisia, Egypt, and South Africa.
Biogeographic Regions: nearctic (Introduced ); palearctic (Native ); oriental (Native ); ethiopian (Introduced ); neotropical (Introduced )
Harmonia axyridis can be found on many crop species in agricultural areas where it has been introduced. It is often found on deciduous trees, flowering plants, and other plant species found in open areas. This species tends to live in open fields, agricultural areas, and meadows.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland ; forest ; scrub forest
Other Habitat Features: suburban ; agricultural
In its native range, Harmonia axyridis generally has two generations per year, but in some places five generations have been observed. Adults tend to live 30 to 90 days, contingent on temperature, although some have lived over three years. Whichever generation receives cues to diapause will generally live through winter, with reproduction then occurring in spring.
Range lifespan
Status: wild: 3 (high) years.
Typical lifespan
Status: wild: 30 to 90 days.
Harmonia axyridis is oval shaped and convex. It is a polymorphic species, with three main color morphs: red or orange with zero to many black spots (form succinea), or black with either four orange spots (form spectabilis) or two (form conspicua). Several less common morphs exist as well. Darker morphs are more common in its native range, with red or orange morphs more common in Europe and North America. The pronotum is generally white with four black spots that tend to form an "M" shape. This species has very distinct, square "shoulders." The last ventral segment on its abdomen differs between male and female individuals.
The eggs of H. axyridis are approximately 1.2 mm in length and yellow in color. Just before hatching, eggs darken to a gray or black coloration.
The larvae of H. axyridis have long bodies and are black with orange coloration (including two long orange lines on the dorsal-lateral areas of the abdomen, which start to develop after the first instar and are complete by the fourth and final instar). They have double-branched spines (scoli) running down the length of the body. The larval stages often grow longer than the final adult individual, starting at an approximate length of 1.9 to 2.1 mm in the first instar and growing to 7.5 to 10.7 mm in the fourth instar. Larvae vaguely resemble tiny black and orange alligators.
Pupae are exposed and generally shaped like an elongated dome, often attached to leaves. They tend to be orange, with the fourth instar exoskeleton still attached at the point of substrate attachment.
Range length: 5 to 8 mm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry ; polymorphic ; poisonous
Sexual Dimorphism: sexes alike
Many species of bird prey on Harmonia axyridis. The pentatomid, Podisus maculiventris is known to prey on H. axyridis, as well as many species of ants, including the red imported fire ant, Solanopsis invicta. Interspecies predation also occurs, though only when the other coccinellids are larger than the H. axyridis prey. Cannibalism on eggs and larvae is very prevalent among Harmonia axyridis populations, with some studies showing up to 50% cannibalism of eggs.
To defend itself, Harmonia axyridis produces isopropyl methoxy pyrazine (IPMP), which it secretes from its tarsi when agitated. This is highly concentrated in the hemolymph and is used as a chemical defense mechanism. Further, this species has antimicrobial agents in its hemolymph that provide defense against Gram-positive and Gram-negative bacteria as well as yeast. This species displays aposematism, as its red and black elytra can deter predators, acting as an apparent warning sign.
Known Predators:
Anti-predator Adaptations: aposematic
Harmonia axyridis secretes pheromones to attract mates and at close distances may use sight. Reproduction is sexual, with internal fertilization of the ova. Studies show that many females are selective of male mates, often deciding on their mates based on the color of male elytra. This seems to be a selective preference, as certain morphs tend to evade predation more effectively. Even so, the species is generally polgynandrous, with individuals ultimately mating many times with many different individuals. After mating, males do not exhibit any apparent defense mechanisms to ensure the eggs are fertilized.
Mating System: polygynandrous (promiscuous)
Females of Harmonia axyridis will produce many eggs per season, averaging an approximate rate of 25 eggs per day. Individuals tend to lay egg clusters, with numbers ranging between 20 and 30 eggs per cluster. This species will breed continuously during its lifetime. Breeding is contingent on temperature, with lower temperatures increasing pre-mating and pre-oviposition periods. Females may lay unfertilized eggs along with the fertilized eggs, which are used by larvae as food sources in conditions where aphids and scale insects are scarce.
Breeding interval: Individuals will breed often and continuously over the duration of adulthood.
Breeding season: Harmonia axyridis will start to breed as soon as temperatures increase beyond approximately 12°C (50°F).
Range eggs per season: 1642 to 3819.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous
There is virtually no parental investment in this species aside from females depositing nutrients in eggs. Additionally, females may lay unfertilized eggs along with the fertilized eggs, ensuring a food source for the larvae upon hatching. Otherwise, larval individuals are independent, surviving on their own after hatching.
Parental Investment: pre-hatching/birth (Provisioning: Female)
