How does a bed bug larva bite? - briefly
A bed‑bug nymph pierces the skin with its elongated beak, injects saliva containing anticoagulants, and feeds on the resulting blood pool. The bite is initially painless, with symptoms such as redness or itching appearing several hours later.
How does a bed bug larva bite? - in detail
Bed‑bug larvae, technically first‑instar nymphs, possess a piercing‑sucking mouthpart called a stylet bundle. The bundle consists of two elongated maxillary tubes that form a channel for fluid intake and two mandibular tubes that act as a drill. The cuticle of the larva is soft, allowing rapid extension of the stylets through the epidermis.
Feeding proceeds through a defined sequence:
- Detection of a host by thermoreceptors and CO₂ sensors on the antennae.
- Approach and positioning of the abdomen against the skin surface.
- Activation of the mandibular stylets to create a microscopic puncture, typically 0.1–0.2 mm in diameter.
- Insertion of the maxillary tubes into the dermal capillary network.
- Injection of saliva containing anticoagulants (e.g., apyrase), vasodilators, and anesthetic peptides that prevent clotting and reduce host perception.
- Suction of blood through the maxillary channel, driven by negative pressure generated by the larva’s cibarial pump.
- Retraction of the stylets and departure from the feeding site after 5–10 minutes.
The salivary cocktail includes enzymes that degrade fibrinogen, histamine‑blocking proteins, and compounds that suppress local immune responses. These agents ensure a continuous flow of blood and minimize irritation, allowing the larva to consume up to 0.2 µL per feeding bout.
After engorgement, the larva retreats to a concealed refuge, where it digests the meal and undergoes molting to the second instar. The entire process repeats with each successive stage, increasing feeding efficiency and blood volume intake.