Injurious and Venomous Arthropods

Skin lesions, allergic reactions, direct injury, and transmission of vector-borne diseases

What are the key health effects caused by biting and stinging arthropods?

Through mouthparts, stingers, urticating hairs, venom proteins, and saliva that can lead to secondary bacterial infections.

How do arthropods cause direct damage to tissue?

Staphylococcus or Streptococcus infections.

What bacterial infections may follow from scratching bites/stings?

Their wing scales (converted hairs) can become airborne, leading to dermatitis, eczema, asthma.

How can butterflies cause allergic reactions?

Biting and chewing, sponging, piercing-sucking (important for pathogen transmission).

What are the three types of insect mouthparts relevant to biting?

Visual cues, vibrations, movement, alarm chemicals, or nest disturbance.

What triggers arthropod stinging behavior?

A modified ovipositor with venom and Dufour’s glands.

What anatomical structure is the sting derived from?

Pheromones

What does Dufour’s gland produce?

Bees, wasps, ants.

What insects belong to Hymenoptera?

Symphyta – No constriction between thorax and abdomen
Apocrita – Constriction (petiole) present between thorax and abdomen

What are the two suborders of Hymenoptera and their difference?

Due to barbed lancets in their sting.

Why do worker bees leave their stingers in the skin?

Melittin

What is the primary pain-causing and lethal agent in bee venom?

Hyaluronidase

Which venom component breaks down hyaluronic acid to spread toxins?

Apamin

Which neurotoxin in bee venom blocks potassium channels?

Mast Cell Degranulating Peptide (MCD).

What venom compound causes histamine release?

Dopamine and Noradrenaline.

What components modulate pain perception and heart rate?

Protease inhibitors

What helps venom components resist host degradation?

Tarantula hawk (Pepsis chrysothemis)

What insect causes one of the most painful stings?

Pustules with localized swelling and inflammation.

What kind of lesion do fire ant stings produce?

Buthidae

Which scorpion family is dangerously venomous to humans?

Burning, swelling, stabbing pain, and in severe cases: nausea, vomiting, paralysis, renal failure, or anaphylaxis

What symptoms are caused by urticating caterpillars?

Brown recluse spider (Loxosceles spp.).

Which spider is known for necrotic lesions?

Sphingomyelinase D.

What is the major necrosis-causing enzyme in brown recluse venom?

α-Latrotoxin

What neurotoxin is in black widow (Latrodectus spp.) venom?

Central white spot with surrounding erythematous halo

What characterizes a hymenopteran sting?

Urticarial wheals, papules, vesicles, sometimes scarring or nodules

What symptoms follow insect bites?

Scrape off stinger, wash area, apply cold compress, take antihistamines and acetaminophen

How should bee stings be treated initially?

Soap and water, cold compress, 1% hydrocortisone cream, antihistamines, and acetaminophen

What helps treat insect bites?

Tick (Lyme disease)

What insect bite is most associated with a "bullseye" rash?

Bed bugs

Which insect typically bites in a line on the body?

Flea bites

What bite causes clustered bites on ankles/legs and turns white on pressure?

Kissing bug

What bug bite is associated with Chagas disease?