Exploring Mosquito Diversity in Your Environment: A Guide to Identifying Adult Mosquito Species 

While samples should always be brought into the lab for proper identification when possible, being able to identify the more common mosquitoes in your region is a great skillset to have when working in the field – recognizing patterns in mosquito species can also impact control efforts in real time.  

Today, Senior Field Scientist at Clarke, Andrew Rivera, walks through identifying common mosquitoes through their physical characteristics, narrowing down genera to specific species and ultimately enabling filed technicians to link behaviors they observe in the field to these species. In sum, this will cover: 

• General Tips for Getting Started with Mosquito Identification
• Recognizing Common Mosquito Genera
• Step-by-Step Process for identifying adult mosquitoes

What Insects Look Like Mosquitoes – But Aren’t?

Before we start on identifying adult mosquito species and their genera, a word of caution – look out for imposters! 

Mosquito imposters are insects that resemble mosquitoes but belong to different families or groups. When distinguishing between mosquitoes and their imposters, consider factors such as size, body structure, behavior, and habitat. Mosquitoes have specific characteristics like a long proboscis, distinctive markings, and a particular resting posture that can help you differentiate them from other insects, which we’ll cover in the next section. 

• Crane Flies (Tipulidae): Crane flies are often mistaken for giant mosquitoes but do not bite. They have long, slender bodies and extremely long legs, resembling giant mosquitoes. 

• Gnats (Various Families): Gnats are small flying insects, sometimes confused with mosquitoes. They can be found in damp soil or decaying organic matter. 

• Mayflies (Ephemeroptera) are aquatic insects important in healthy river ecosystems. They have delicate bodies and are known for their short adult lifespan. 

• Moth Flies (Psychodidae): Moth flies, also known as drain flies or owl midges, are small hairy flies that can breed in sewers or damp indoor areas. 

• Non-biting Midges or Biting Midges (Ceratopogonidae): Non-biting midges occur in both inland and coastal areas with natural and man-made bodies of water. Biting midges, also called no-see-ums, are tiny flies that are more petite than mosquitoes and can deliver painful bites.  

Photograph by Ed T. Schmidtmann, USDA/ARS

Adult Mosquito Identification

Looking at the chart above, there’s a lot going on and plenty of small details that can be confusing or too small to see in the field.  

Instead, focus on these three key body parts for identifying adult mosquito species: maxillary palpi, tip of the abdomen (cerci), and proboscis. These three components are all you’ll need to be familiar with when navigating through the diverse characteristics of mosquito species from this chart. 

The 90% Rule: Ruling Things Out 

A large part of identification is ruling out possibilities and distinguishing between the subtle variations that each mosquito has. Look for key features using markings, wing patterns, antennae and palps structure, unique colorations, mouthparts lengths, and resting positions as indicators of mosquito species. 

Geography as a Major Clue 

Different mosquito species thrive in various environments, so understanding a region’s geography and habitats can help begin to narrow down their species possibilities. Understand the environmental factors shaping each species – what temperatures, water types, seasons, and other features they prefer and thrive in.  

Grouping Based on a Single Feature 

Group potential candidates based on a single distinguishing feature to lay the foundation for a more detailed exploration into their characteristics. Consider this phase as a strategic way to start funneling mosquitoes into a specific species. 

Recognizing Common Adult Mosquito Genera 

One of the biggest building blocks for being able to easily identify adult mosquitoes in the field by eyesight is being familiar with the common adult mosquito genera. 

Look for characteristics distinct of the Aedes, Culex, Anopheles, and Culiseta genera while keeping in mind their habitats and behaviors. 

Aedes Species Identification 

• Body Shape: Pointed abdomen 
• Activity Time: Dawn, dusk and daytime biting species 
• Feeding Preferences: Humans and mammals 
• Habitat: Urban and suburban areas including temporary pools and containers  
• Transmitted Diseases: Dengue & yellow fever, chikungunya, Zika virus 
• Distinctive Features: Often with Black and white striped legs and bodies, aggressive biters 

Culex Species Identification 

• Color: Dark brown to black 
• Body Shape: Rounded abdomen  
• Activity Time: Active at dawn and dusk 
• Feeding Preferences: Birds and mammals 
• Habitat: Natural water sources, standing water in ditches and ponds. 
• Transmitted Diseases: West Nile virus, encephalitis 
• Resting Position: Parallel 
• Distinctive Features: Prominent proboscis 

Anopheles Species Identification

• Color: Brownish 
• Body Shape: Long spindly legs 
• Activity Time: Dusk and dawn 
• Feeding Preferences: Humans and animals 
• Habitat: Breeds in natural water sources including ponds with algae and vegetation 
• Transmitted Diseases: Malaria 
• Resting Position: Humpbacked unique 45° angle 
• Distinctive Features: Long palps, spotted wings  

Culiseta Species Identification 

• Color: Brownish 
• Body Shape: Larger in size in comparison to other species 
• Activity Time: Night 
• Feeding Preferences: Birds and mammals 
• Habitat: Wooded areas, favoring damp and shaded spots within woodlands 
• Transmitted Diseases: Eastern equine encephalitis (EEE) 
• Resting Position: Parallel 
• Distinctive Features: Larger in size and long drooping proboscis

Step by Step Field Identification Questions 

With this familiarity with some of the more common adult mosquito genera, you can now run through a simple process to eliminate and identify mosquito species. 

Step 1: Anopheles? 

• Anopheles mosquitoes have maxillary palps nearly as long as the proboscis. 
• Non-Anopheles mosquitoes have palps shorter than the proboscis. 
• Anopheles mosquitoes rest at a distinct 45° angle. 

Step 2: Pointy Butt? 

• Pointy butts are characteristic of Aedes and Psorophora. 
• Not pointy butts are found in Culex, Culiseta, Coquillettidia, and Mansonia. 

Step 2a: Aedes or Psorophora? 

• Psorophora has pale patterning starting at the far end of the segment and moving towards the body. 
• Aedes has pale patterning starting at the near end of the segment and moving away from the body. 
• Psorophora tend to fly directly to their feeding target and can be abundant after floods 

Aedes (left) Psorophora (right)

Step 3: Something Weird? 

• Look for unique features like iridescent blue, thin lines, or unusual leg characteristics. 
• Consider the possibility of Coquillettidia perturbans or Mansonia species by examining their wing markings that will look almost dusty in appearance due to their scales being uniquely broad and the presence of a pointy or non-pointy butt. 

Step 4: Culiseta or Culex? 

• Some details may not be visible to the naked eye, requiring the use of a microscope to ensure a clear and accurate identification of the mosquito 
• Evaluate the length of the proboscis relative to the maxillary palps which is four times as long as the palps 

Culex (left) Culiseta (Right)

Identifying Adult Mosquito Species: Putting It All Together  

Once you have a background basis of the common mosquito genera, it’s easy enough to narrow down to a species using their key indicators such as body parts – maxillary palpi, tip of the abdomen (cerci), and proboscis – markings, wings, behavior, and habitats.  

 When identifying adult mosquitoes in the field, keep in mind the following: 

• Habitat Awareness: Consider specific habitats where each species is commonly encountered. 
• Seasonal Patterns: Be aware of the time of year when each species is most abundant. 
• Behavioral Cues: Note the time of day for each species, aiding in identification. 
• Visual Inspection: Observe distinctive markings, size, and coloration for accurate identification. 

Overall, explore essential features, implement a systematic approach, and incorporate geographical cues to enhance your mosquito identification skills. Happy mosquito spotting!