‘Reverse’ identification key for mosquito species More and more people are getting involved in the surveillance of invasive mosquito species Species name used Synonyms Common name in the EU/EEA, not just professionals with formal training in entomology. There are many in the key taxonomic keys available for identifying mosquitoes of medical and veterinary importance, but they are almost all designed for professionally trained entomologists. Aedes aegypti Stegomyia aegypti Yellow fever mosquito The current identification key aims to provide non-specialists with a simple mosquito recog- Aedes albopictus Stegomyia albopicta Tiger mosquito nition tool for distinguishing between invasive mosquito species and native ones. On the Hulecoeteomyia japonica Asian bush or rock pool Aedes japonicus japonicus ‘female’ illustration page (p. 4) you can select the species that best resembles the specimen. On japonica mosquito the species-specific pages you will find additional information on those species that can easily be confused with that selected, so you can check these additional pages as well. Aedes koreicus Hulecoeteomyia koreica American Eastern tree hole Aedes triseriatus Ochlerotatus triseriatus This key provides the non-specialist with reference material to help recognise an invasive mosquito mosquito species and gives details on the morphology (in the species-specific pages) to help with verification and the compiling of a final list of candidates. The key displays six invasive Aedes atropalpus Georgecraigius atropalpus American rock pool mosquito mosquito species that are present in the EU/EEA or have been intercepted in the past. It also contains nine native species. The native species have been selected based on their morpho- Aedes cretinus Stegomyia cretina logical similarity with the invasive species, the likelihood of encountering them, whether they Aedes geniculatus Dahliana geniculata bite humans and how common they are. Aedes communis Ochlerotatus communis Snowpool mosquito If you want to further develop your identification skills, you can consult ‘Mosquitoes - Identi- fication, Ecology and Control. Third Edition’ [1] or identification tools available online, such as Culiseta annulata MosKeyTool: https://www.medilabsecure.com/moskeytool.html. Culiseta longiareolata Different scientific names are available for the species included in this key. Table 1 provides an overview of the scientific names used in the key [2] and names based on the revisions made by Aedes vexans Aedimorphus vexans Reinert and colleagues [3-7] that can be found in scientific literature. We hope that this will aid House mosquito, Northern Culex pipiens communication between health professionals and scientists. house mosquito Aedes cantans Ochlerotatus cantans Aedes caspius Ochlerotatus caspius Salt marsh mosquito 1 What is/is not a mosquito? Scientific classification of mosquitoes Diptera that look similar to Culicidae Kingdom Phylum Class Order Suborder Family Genus Species 2 2 3 e.g e.g Animalia Arthropoda Insecta Diptera Nematocera Culicidae Aedes albopictus 1 Body structures 1 © Anders Lindström/SVA © Anders © Anders Lindström/SVA © Anders Head Thorax Abdomen Tarsus of hindleg Mycetophilidae or Fungus gnats Limoniidae or Crane flies Tibia V Scutum Short mouth parts (1); markedly humped Short mouth parts [1]; very long legs [2]; IV thorax [2]; 2–14mm slender body [3]; 2–11mm III Antenna II I 3 2 2 Palp Tarsomeres (tarsal segments) Proboscis 1 3 1 © Anders Lindström/SVA © Anders Lindström/SVA © Anders 1 Ceratopogonidae or Biting midges Chironomidae or Chironomids or Culicidae or True (biting) mosquitoes Short proboscis, not needle-like [1]; hooped Non-biting midges (Culex pipiens female) thorax [2]; wing without scales [3]; 1–3mm Short mouth parts [1]; no scales on wing [2]; Females with elongated ‘needle-like’ mouth shape of thorax, ‘hooped’ [3]; ~10mm parts [1]; wings with scales; long legs; size of mosquito 3–6mm; Female vs male mosquitoes 2 Hairy antenna 1 Feathery antenna 1 © Anders Lindström/SVA © Anders Lindström/SVA © Anders Anisopodidae or Wood gnats Tipulidae or Crane flies Short mouth parts [1]; ~4–12 mm No needle-like proboscis; looks like an oversized mosquito; slender body [1]; Female Male stilt-like legs [2]; wing span 1–6.5 cm 22 Life cycle of an Aedes mosquito Female taking blood meal Adult Adults mating Female laying eggs Eggs Pupa Larva 3 © Disa Eklöf/SVA © Disa Female mosquitoes Aedes aegypti Aedes albopictus Aedes japonicus Aedes koreicus Aedes triseriatus p.6 p.7 p.8 p.9 p.10 Aedes atropalpus Aedes cretinus Aedes geniculatus Aedes communis Aedes cantans Aedes vexans p.11 p.12 p.13 p.14 p.15 p.16 © Disa Eklöf/SVA © Disa Aedes caspius Culex pipiens Culiseta longiareolata Culiseta annulata p.17 p.18 p.19 p.20 0 2.5 5 mm Invasive Native 4 4 © Disa Eklöf/SVA © Disa Male mosquitoes Aedes aegypti Aedes albopictus Aedes japonicus Aedes koreicus p.6 p.7 p.8 p.9 © Disa Eklöf/SVA © Disa Aedes triseriatus Aedes atropalpus p.10 p.11 0 1.25 2.5 mm Invasive 5 Yellow fever mosquito Aedes aegypti 1 © Disa Eklöf/SVA Stegomyia aegypta Morphological characteristics 1. Scutum (dorsal part of the thorax) has silver Invasive scales in the shape of a lyre on a black background. 2. Medium size. 3 3. Contrasting black-and-white colouration. 4. Silvery-white markings on legs and abdomen. 4 Easily-confused species • In Europe, female Aedes aegypti will lay their eggs in artificial water containers, much like Aedes albopictus; Aedes cretinus Aedes albopictus. Suitable habitats include earthenware pots and water tanks, uncovered ♀ Status in Europe cisterns, empty cans, flower pots, broken • Exotic, invasive bottles or discarded tyres. © Anders Lindström/SVA © Anders • Origin: Tropical Africa • On the island of Madeira, Aedes aegypti is active throughout the year, with a peak in abundance from August to October. Distribution • The eggs are resistant to desiccation. Unlike https://bit.ly/ Aedes albopictus, Aedes aegypti cannot 3lucnDG produce diapausing eggs resistant to frost. Likely point of entry International trade and travel, airports. Ecology (habitat, breeding sites) Biting habits • Originally Aedes aegypti was found in forested areas, using tree holes as habitats. The • Human, occasionally other mammals. species is now commonly found in tropical • The females feed predominantly during the and sub-tropical areas, in close proximity to day in shaded places and only occasionally humans. It thrives well in urban and peri-urban during the night in lit rooms. environments. • Females can feed multiple times between egg laying. ♂ 6 © Anders Lindström/SVA © Anders (Asian) tiger mosquito Aedes albopictus 1 © Disa Eklöf/SVA Stegomyia albopicta Morphological characteristics 1. Diagnostic characteristic: scutum (dorsal part of the thorax) with a median silver-scale line on a black background. Invasive 2. Medium size. 3. White stripes beside the median white line on the scutum do not reach the middle of the scutum. Easily-confused species been shown to be most active during the period May-September. Aedes cretinus, Aedes aegypti • Adult Aedes albopictus females can produce eggs able to survive periods of frost during the Status in Europe winter (diapausing eggs). • Exotic, invasive • Diapausing eggs of European Aedes albopictus • Origin: Asia have been shown to be able to survive a cold spell of -10°C, whereas eggs of tropical Aedes ♀ albopictus can only survive -2°C. © Anders Lindström/SVA © Anders Distribution • Larvae develop in natural or artificial water https://bit.ly/ containers. Artificial aquatic habitats include 38RKu3F tyres, barrels, rainwater gulley catch basins and drinking troughs. Natural habitats are places where terrestrial plants harbour water Likely point of entry e.g. tree holes. Eggs of Aedes albopictus are often imported in used tyres or hydroponic plant containers. Other ways of introduction include vehicles in which adult Aedes albopictus individuals can ‘hitchhike’ across borders. Biting habits • Adult females bite aggressively, usually during the day outdoors, but also during the Ecology (habitat, breeding sites) night indoors. • Aedes albopictus feeds on humans, • In Europe Aedes albopictus prefers urban and domestic and wild animals, reptiles, birds suburban habitats. and amphibians, depending on host • In a temperate climate Aedes albopictus has availability. ♂ 7 © Anders Lindström/SVA © Anders Asian bush or rock pool mosquito 1 Aedes japonicus japonicus Morphological characteristics © Disa Eklöf/SVA Ochlerotatus japonicus japonicus, Hulecoeteomyia japonica japonica 1. The main diagnostic characteristic is a scutum (dorsal part of the thorax) with several lines of yellowish scales on a black background. 2. Only three white scale patches on hind legs (different from Aedes koreicus). Invasive 3. Relatively large. 4. White scale patches on black legs. 4 5. Dorsal plates of the abdomen have lateral and median pale patches at the base of each segment that do not form complete bands. 6. Tarsus 4 and 5 of hind legs almost entirely dark. 5 2 6 Easily-confused species can develop in a large range of both natural and artificial aquatic container habitats Aedes koreicus including tree holes, tyres, bird baths, and all breeding sites rich in organic matter. ♀ Status in Europe • Aedes japonicus can produce freeze- and • Exotic, invasive desiccation-resistant diapausing eggs that can © Anders Lindström/SVA © Anders • Origin: Asia remain dormant over winter and hatch once environmental conditions become favourable. Distribution https://bit.ly/