When people ask if “baby mosquitoes” can bite, the answer depends on what stage of a mosquito’s life they are referring to. Mosquitoes undergo a complete metamorphosis, transforming significantly through different life stages. Understanding these stages is important to know which forms are capable of biting.
The Mosquito’s Journey Through Life
Mosquitoes develop through four distinct stages: egg, larva, pupa, and adult. The initial three stages occur in water. Female mosquitoes lay their eggs individually or in rafts on the surface of standing water, along its edges, or in areas prone to flooding. These eggs can hatch within a few days, depending on temperature and species, or some may remain dormant for months or even years until conditions are right.
Once an egg hatches, it becomes a larva, often called a “wiggler” due to its characteristic S-shaped movement in the water. Larvae are aquatic and breathe air through a tube-like siphon that extends to the water’s surface. They feed and grow, undergoing four molts before transforming into the pupal stage.
The pupa, known as a “tumbler,” is also aquatic but does not feed. This comma-shaped stage is a period of transformation where the mosquito develops into its adult form. Pupae are active, tumbling away from disturbances, and breathe through two respiratory tubes called trumpets. This stage typically lasts from one to four days, after which the adult mosquito emerges from the pupal casing and takes flight.
When Mosquitoes Can Bite
Only adult mosquitoes bite, and specifically, it is the adult female that bites people and animals. Male mosquitoes do not bite. Female mosquitoes require a blood meal to obtain the protein and lipids necessary for producing their eggs. Without this blood, most female mosquitoes cannot develop viable eggs.
When a female mosquito bites, she uses a specialized mouthpart called a proboscis. This proboscis is a complex structure made up of several needle-like stylets encased in a protective sheath. Upon landing on a host, the mosquito uses tiny saw-like maxillae and mandibles to pierce the skin. She then injects saliva into the host, which contains anticoagulants to prevent blood clotting and vasodilators to increase blood flow, making it easier to draw blood.
The mosquito then uses a straw-like tube, the labrum, to suck blood. This process allows the female to extract a significant amount of blood relative to her size. The substances in her saliva also cause the itchy, irritating reaction commonly associated with mosquito bites. Female mosquitoes can detect hosts by sensing exhaled carbon dioxide, body heat, and certain skin odors.
Why Only Adult Female Mosquitoes Bite
The reason only adult female mosquitoes bite lies in their biological needs and physical adaptations. Mosquito eggs, larvae, and pupae are aquatic and lack the mouthparts for piercing skin or feeding on blood. Larvae, or “wrigglers,” are filter feeders, consuming microscopic organisms like algae, bacteria, and other organic debris in the water. They use brush-like structures near their mouths to filter these food particles.
Pupae are a non-feeding, transitional stage. During this phase, the mosquito’s internal structures reorganize to form the adult insect. They rely on energy reserves built during the larval stage and do not possess mouthparts for feeding.
Adult male mosquitoes do not bite. Their mouthparts are not designed for piercing skin; instead, they feed on plant nectar, fruit juices, and other sugary plant secretions for energy. Male mosquitoes lack the specialized stylets found in females required to penetrate skin and draw blood. While both male and female mosquitoes consume plant sugars, only the female requires the protein-rich blood meal for egg development.