ENVIRONMENT ASSESSMENT REPORT FOR Aedes koreicus 1. Taxonomy a. Family: Culicidae b. Genus: Ochlerotatus (the genus Ochlerotatus was recently elevated from a subgenus of Aedes. Many mosquito biologists in Australia still use the Aedes genus to avoid confusion, since decades of scientific literature refer to medically important mosquitoes with the former genus name Aedes, so in the report I will refer to Aedes koreicus). c. Species: koreicus d. There are no known subspecies of Ae. koreicus. e. Edwards, F.W. 1917. Bull. Ent. Res. vii: 212-213. f. No common names are yet known for this species. g. This is not a genetically-modified organism (GMO). 2. Status of Aedes koreicus under CITES Aedes koreicus is listed neither on Appendix I or II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). 3. Ecology of Aedes koreicus a) The longevity of Aedes koreicus is unknown. A closely related species, Aedes japonicus, is known to have a half-life in captivity of 15-35 days, depending on food available and presence of competing species, with a maximum age in captivity of 40-75 days (Alto 2009). Longevity in the wild is not known, but for mosquitoes, it is usually shorter than longevity in captivity. b) Size and weight of mosquitoes will differ depending on temperature, food availability and presence of competitors in their larval habitat. However, based on collected samples in Italy, the range of lengths (from antenna to tip of abdomen) is 6.8 – 7.4 mm for adult females (see Figure 1 below for typical female) and 5.3 – 6.9 mm for males. The dry weight of specimens is 0.1-0.2 mg for males and 0.5-0.6 mg for females (measured by S. Ciocchetta). Figure 1. Collected Ae. koreicus female (left) and male (right) with antennal, thoracic and abdominal lengths measured (collected in Verona, Italy, photos: F. Montarsi). c) Male and female mosquitoes are quite easy to differentiate, based on antennae (males have much more feathery antenna, see photos). Ae. koreicus adults have some superficial resemblance to a few native Australian mosquitoes (e.g. Aedes notoscriptus, Ae. palmarum) and to invasive species Ae. aegypti and Ae. albopictus. However, the combination of golden hairs on the thorax as well as the distinctive vertical stripe along the scutum flanked by two shorter vertical stripes (see Figures 2A-2B below) makes it relatively easy to identify this species with at most a small amount of training. Also photographs of adults are available (see Figure 2 below), we do not have photos of the larvae or pupae at this time. Figure 2. A) Adult female (photo: A. Drago) and B) adult male of Aedes koreicus (photo: F. Montarsi). d) The native range of Ae. koreicus is Korea, China, Japan (Hsiao and Bohart 1946) and Russia. Miyagi (Miyagi 1971) reported finding larvae in artificial containers near houses in Korea. Miles (Miles 1964) reported finding larvae in brackish seaside pools in the far-eastern (former) USSR. Kim et al (Kim 2005) reported finding Ae. koreicus larvae in tyres and rock pools in Korea. Population limiting influences for Ae. koreicus would include habitat availability (rock pools, artificial containers, used tyres) and predation (Australia has a native predatory mosquito Toxorhynchites speciosus, as well as other invertebrate predators such as backswimmers, that prey on mosquito larvae found in containers and tyres). e) Aedes koreicus is not known to be migratory. f) Aedes koreicus eggs are able to survive freezing during the winter months. g) Larval, pupal and adult stages of Ae. koreicus breathe air (the aquatic stages breathe air at the water surface using a siphon). h) Habitat requirements: a. Physical parameters: i. Salinity: the aquatic larvae of Ae. koreicus are most commonly found in temperate climates in containers filled with rain water, but they have also been found in brackish rock pools. ii. Since mosquito larvae breathe air through a siphon, they do not necessarily need well-oxygenated water. That said, the requirements for water quality and oxygen content have not been evaluated for Ae. koreicus. iii. pH: The full range of pH that Ae. koreicus can tolerate has not been investigated. iv. Temperature: Precise temperature evaluations have not been done for Ae. koreicus, but the species is known to live in temperate climates in Korea, Japan, Russia, Belgium and northern Italy. Its eggs are able to survive freezing during the winter. b. Climate: Ae. koreicus is known to live in temperate climates, and the eggs can survive freezing during the winter. It is unknown how Ae. koreicus would fare in subtropical and tropical climates. c. Aedes koreicus larvae have been found in rock pools, used tyres and other artificial containers. d. Aedes koreicus has not been found to nest in marshes, swamps, estuaries, lakes, ponds, dams, rivers, channels, streams, banks of water bodies, coastal beaches or sand dunes. i) Social behaviour. Mosquitoes tend to be for the most part solitary. Larvae from the same egg batch would cohabit in a water source, but that wouldn’t be considered “social”. Adult males of some species form swarms in order to attract females, but the mating behaviour of Aedes koreicus has not been studied. j) Mosquitoes are not known to be territorial or aggressive to other species, beyond females seeking out warm-blooded hosts to blood feed. k) Injury and harm to humans: Female Aedes koreicus can bite humans, which can cause an allergic response including reddening, itchiness and slight swelling at the bite site. Their status as a disease vector is not well known. Japanese encephalitis virus was detected in some collected specimens (Miles 1964). Reproductive Biology of Aedes koreicus a) The reproductive biology of Ae. koreicus has not been studied, but most adult male mosquitoes are sexually mature by the second day of adulthood, and most females mosquitoes by the third day of adulthood. b) For most blood-feeding mosquito species, after the female mates, she requires a blood meal to gain the protein needed to produce eggs. Most mated females will lay eggs three or four days after a successful blood meal. Some mosquitoes are autogenous, meaning they do not require a blood meal to lay eggs. It is unknown if Ae. koreicus is autogenous; however, closely related species (e.g. Ae. notoscriptus, Ae. japonicus) are not autogenous, so it is unlikely. Breeding sites for mosquitoes are almost always stagnant water. For Ae. koreicus, brackish rock pools, used tyres and artificial containers around buildings are all suitable habitats. c) It is not known how often Aedes koreicus breeds. d) Not applicable (these are not sessile aquatic invertebrates). e) Mosquitoes have never been known to change sex. f) Hybridization involving Aedes koreicus has not been observed. It is notable that they have not been known to hybridize with the closely related Ochlerotatus japonicus species complex (Cameron 2010) g) It is unknown if Ae. koreicus can hybridise with Australian native species, but considering that they haven’t been known to hybridise with closely-related Asian species (see above), it is not likely. h) All mosquitoes are single-sexed. No hermaphrodites have been reported. 4. Feral Populations a) Aedes koreicus has been found to have established breeding populations in Belgium (Versteirt 2012) and northern Italy (Capelli 2011). b) Despite the fact that it is known to bite humans, Ae. koreicus is not known to be a pest in its known or introduced habitat. There are no eradication programs. c) The only known introductions of Ae. koreicus into other countries are in Belgium and Italy (see above). Means of entry is unknown, though imported tyres or plant cuttings are the most likely routes (Cappelli et al 2011). 5. Environmental risk assessments of the species No risk assessment has been carried out in Australia or overseas for Ae. koreicus. 6. Likelihood that Aedes koreicus could establish a breeding population in Australia a) The diet of adult and larval Ae. koreicus is very similar to that of native Australian mosquitoes: aquatic detritus, algae and microorganisms for the larvae, and nectar and bird/mammal blood for the adults. Ae. koreicus would be able to find food in Australia. b) Since these mosquitoes breed in artificial containers such as plant pots, used tyres and bird baths, it would be possible for them to continue breeding even during a drought. Eggs of all Aedes mosquitoes can survive in a dry state for up to a few months until triggered to hatch by rain. In temperate areas of Australia, the eggs are sufficiently cold-tolerant to survive the winter. c) Aedes koreicus seems to be well-adapted to human modified habitat. They have been found breeding in sewers, artificial containers and used tyres. d) Mosquitoes can lay over a hundred eggs in their lifetime, so that could increase the likelihood of Ae. koreicus to establish. This is nothing unique to Ae. koreicus, however. e) The most likely limiting influence on Aedes koreicus in Australia would be competition from native mosquitoes. Ae. notoscriptus, for instance, is a container breeding mosquito present all over Australia, so it would compete with Ae. koreicus over its entire range. f) Since Aedes koreicus is not present in Australia, any imported individuals should be limited to research facilities with appropriate quarantine facilities and experienced staff to prevent their escape into the environment. The establishment of feral populations in Australia would therefore be extremely unlikely. 7. Potential Impact of Aedes koreicus Should it Become Established in Australia a) Aedes koreicus fills a similar niche as a number of native Australian container-breeding mosquitoes, most notably Ae. notoscriptus. They would be expected to compete for larval habitats and food (i.e.