Download Draft environment assessment report for Aedes koreicus

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)
d)
e)
f)
It is not known how often Aedes koreicus breeds.
Not applicable (these are not sessile aquatic invertebrates).
Mosquitoes have never been known to change sex.
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. aquatic microorganisms
and detritus) should Ae. koreicus be released into the environment.
b) Aedes koreicus adult females are known to bite humans and sea birds
in Russia (Miles 1964). They may bite other mammal and birds species, but this
has not yet been observed or evaluated. They may bite domestic livestock, but
this has not yet been observed. Mosquito bites can cause an allergic response
including reddening, itchiness and swelling around the site of the bite. Aedes
koreicus has been reported to be able to be infected with Japanese encephalitis
virus (Miles 1964) and dog heartworm (Ludlam et al 1970).
c) Impacts on habitat and local environments:
a) This species will not reduce ground vegetation cover.
b) This species does not dig burrows.
c) This species has not been known to damage native animals’
habitats, natural communities, native plants, forestry or agriculture.
d) This species is highly unlikely to inhibit tree seedling
regeneration.
e) This species is highly unlikely to spread weeds.
d) Behaviours that cause environmental degradation
a) Aedes koreicus is not known to exhibit any behaviours that
cause physical disturbance to the environment.
b) This species is not known to eat or disturb wetlands or wetland
vegetation.
c) This species is not known to cause pollution of water bodies.
d) The known habitats of Aedes koreicus are artificial containers,
used tyres, and rock pools. These are not particularly sensitive environments in
general, and there is no indication they would be aversely affected by Ae.
koreicus.
e. Impacts on primary industries
a) Aedes koreicus is not known to cause damage to livestock,
poultry, etc., although it may bite livestock or poultry that are near breeding
areas. This mosquito is not know to transmit any livestock or poultry diseases,
and bites are unlikely to have a serious impact (e.g. milk production, egg laying,
general health, etc.) unless there were large numbers of biting mosquitoes.
b) This species is not expected to eat or damage any plants or
plant parts.
c) This species is not expected to compete with livestock.
d) This species is not expected to have a negative impact on tree
plantations/silvicultural activities in any way.
f) Damage to property
a) Aedes koreicus has not been known to and is not expected to
deface or physically damage buildings, either through physical damage or
depositing excrement.
b) This species is not known to damage fences.
c) This species is not known to damage equipment.
g) Aedes koreicus could potentially be a social nuisance by biting if it is
prevalent near humans in large numbers. This is no different than the social
nuisance already presented by native Australian mosquitoes.
h) Potentially harmful characteristics of Aedes koreicus:
a) Ae. koreicus is known to bite humans and feed on blood. This
can cause itching and swelling at the site of the bite, which can be treated with
any one of a number of ointments or natural treatments. Typical mosquito
repellents available in Australia would be expected to be effective against Aedes
koreicus as well. Ae. koreicus has been reported as a vector of Japanese
Encephalitis virus (JEV) (Miles 1964). Whether this mosquito can transmit JEV
in nature has not been well investigated. There is a JEV vaccine available.
b) Ae. koreicus has been known to bite people. This can cause
itching and swelling at the site of the bite, which can be treated with any one of a
number of ointments or natural treatments. No further injury has ever been
reported from this species to humans. Aedes koreicus has been reported to be
able to be infected with Japanese encephalitis virus (Miles 1964) and dog
heartworm (Ludlam et al 1970).
c) Ae. koreicus has been reported as carrying of JEV (see above),
although whether it can transmit the virus to humans has yet to be investigated.
Other viruses have not yet been tested. In a review by Ludlam et al. (1970), Ae.
koreicus was listed as a potential vector of dog heartworm Dirofilaria immitis.
Research needs to be done to see if this species could transmit other viruses in
Australia if it became established.
8. Conditions or Restrictions to Reduce Any Potential Negative Impacts of
Aedes koreicus
Unintentional import of Ae. koreicus into Australia would most likely be in
the form of eggs or larvae in containers of water. This is a similar ecology to the
invasive Asian tiger mosquito Aedes albopictus. Australia has an eradication
program in place for Ae. albopictus, which was put into action as recently as
December 2012, when Ae. albopictus were discovered in two greenhouses
outside of Melbourne and subsequently eradicated
(http://www.daff.gov.au/about/media-centre/dept-releases/2012/asian-tigermosquito-in-melbourne). Restrictions placed on import of Aedes koreicus should
include limiting importation to research use only, in addition to the
requirements for an import permit and quarantine facilities.
9. Summary of Proposed Activity
a) Our laboratory (Mosquito Control Lab, Queensland Institute of Medical
Research), is collaborating with Istituto Zooprofilattico Sperimentale delle
Venezie (IZSVe) in Verona, Italy, to assess the risk of this newly discovered
invasive mosquito for Europe and Australia. QIMR has the necessary high
containment quarantine facilities, resources and expertise to evaluate the ability
of this mosquito to transmit medically important viruses such as dengue, Ross
River virus, Murray Valley encephalitis, Barmah Forest virus, chikungunya and
West Nile. After these experiments are completed, we will have a more accurate
risk assessment for this species, and any remaining mosquitoes will be
destroyed.
b) We would import about 5000 eggs. Aedes eggs can be laid on paper
towels or similar surfaces, dried out, then hatched up to a couple of months later.
c) The males don’t particularly interact. They may form mating swarms
to facilitate attracting females, but the mating behaviour of this species has not
been studied. No segregation is required.
d) The purpose of importing Ae. koreicus is not for breeding.
e) The mosquito will be used for research purposes only. This may
include genetic studies, protein studies and laboratory behaviour/physiology
studies. We recommend the import of this species be limited to research
purposes only.
f) Our collaborators at IZSVe are planning to establish an Ae. koreicus
captive colony from mosquitoes captured around the city by (northern
hemisphere) summer. They will send us eggs from that colony.
10. Guidelines on How Species Should Be Kept
a) Aedes koreicus will be shipped as eggs in approved IATA packaging by
an approved courier.
b) Mosquitoes are typically kept in secure 30 cm3 cages with a density of
several hundred individuals per cage, and secondarily contained in a
stainless steel cabinet enclosed with stainless steel mesh within an
insectary. Mosquitoes not native to Australia will be contained within
a quarantine approved insectary.
c) Mosquitoes typically hatch in a 50/50 male: female ratio. Since
females live longer than males, a colony with overlapping generations
tends to have more females than males. Breeding is easily controlled
by withholding of oviposition sites within the cage, so populations
within the cage are easily maintained.
d) Aedes koreicus will be kept in a quarantine-approved insectary at the
Queensland Institute of Medical Research (QIMR) in Herston,
Queensland. They will be housed in standard 30.5 x 30.5 x 30 cm
insect cages from BioQuip
(http://www.bioquip.com/search/DispProduct.asp?pid=1450A). These
cages will be secondarily contained within a stainless steel 1.5 m x 41
cm shelving unit enclosed in 100 micron stainless steel mesh. These
mosquitoes will be used for research only, and destroyed when the
research project is complete.
e) Keeping mosquitoes in an enclosed cage does not raise any welfare
issues for the mosquitoes.
11. State/Territory Controls
There are no Commonwealth, state or territory legislative controls on
Aedes koreicus other than quarantine legislation.
Aedes koreicus is required to be imported with an appropriate import
permit and will be contained in a quarantine approved insectary QIMR will meet
any other conditions included on the import permit.
12. Conditions/Restrictions
Aedes koreicus should be approved for import into Australia subject to the
condition it is used for research only in high security facilities. The imported
mosquitoes will also be handled by experienced staff that have completed
quarantine accredited training. The Queensland Institute of Medical Research
(QIMR) already holds exotic mosquitoes so has experience in high containment
requirement.
References Cited
Alto, B. W. (2009). "Interspecific larval competition between invasive Aedes
japonicus and native Ae. triseriatus (Diptera: Culicidae) and adult longevity."
Journal of Medical Entomology 48(2): 232-242.
Cameron, E. C., Wilkerson, R.C., Mogi, M., Miyagi, I., Toma, T., Kim, H.C., Fonseca,
D.M. (2010). "Molecular phylogenetics of Aedes japonicus, a disease vector that
recently invaded Western Europe, North America, and the Hawaiian Islands."
Journal of Medical Entomology 47(4): 527-535.
Capelli, G., Drago, A., Martini, S., Montarsi, F., Soppelsa, M., Delai, N., Ravagnan, S.,
Mazzon, L., Schaffner, F., Mathis, A., Di Luca, M., Romi, R., Russo, F. (2011). "First
report in Italy of the exotic mosquito species Aedes (Finlaya) koreicus, a potential
vector of arboviruses and filariae." Parasites and Vectors 4(188).
Kim, H. C., Wilkerson, R.C., Pecor, J.E., Lee, W.J., Lee, J.S., O'Guinn, M.L., Klein, T.A.
(2005). "New records and reference collection of mosquitoes (Diptera: Culicidae)
on Jeju Island, Republic of Korea." Entomological Research 35(1): 55-66.
Miles, J. A. R. (1964). "Some ecological aspects of the problem of arthropod-borne
animal viruses in the Western Pacific and south-east Asia regions." Bulletin of the
World Health Organization 30: 197-210.
Miyagi, I. (1971). "Notes on the Aedes (Finlaya) chrysolineatus subgroup in Japan
and Korea (Diptera: Culicidae)." Tropical Medicine 13(3): 141-151.
Versteirt, V., Pecor, J.E., Fonseca, D.M., Coosemans, M., Van Bortel, W. (2012).
"Confirmation of Aedes koreicus (Diptera: Culicidae) in Belgium and description
of morphological differences between Korean and Belgian specimens validated
by molecular identification." Zootaxa 3191: 21-32.