Toxicity

Definition

The capacity of a chemical substance, venom, or metabolic product to cause injury, dysfunction, or death to an organism or specific biological structure. In arthropod biology, toxicity is quantified through dose-response metrics such as LD50 (lethal dose for 50% of test subjects) and varies with route of exposure (cuticular contact, injection, ingestion), developmental stage, and physiological state of the target. The concept distinguishes acute toxicity (immediate effects from a single exposure) from chronic toxicity (cumulative damage from repeated or prolonged exposure), and encompasses specialized forms including neurotoxicity, cytotoxicity, and hepatotoxicity.

Etymology

From Medieval Latin toxicus (poisoned), from Latin toxicum (poison), from Greek toxikon (arrow poison, from toxon, bow).

Example

The toxicity of pyrethroid insecticides to honey bees (Apis mellifera) varies dramatically by formulation: microencapsulated lambda-cyhalothrin exhibits prolonged residual toxicity through cuticular contact, whereas emulsifiable concentrates show lower contact toxicity but equivalent oral toxicity when bees consume contaminated nectar.

Synonyms

• poisonousness
• toxic potency

Related Terms

• LD50
• venom
• Insecticide
• Acute toxicity
• Chronic toxicity
• Bioassay
• synergism
• antagonism
• detoxification
• resistance

Usage Notes

Toxicity is an intrinsic property of a substance, distinct from hazard (the likelihood of harm under actual conditions) and risk (probability of adverse outcome). In entomological literature, 'toxicity' properly describes the substance's capacity, while 'poisoning' or 'intoxication' describes the resulting pathological state in the organism. Specialists reserve 'toxic' for substances causing harm at low doses, contrasting with 'harmful' or 'hazardous' for broader mechanical or chemical dangers. When comparing arthropod venoms, toxicity is normalized per unit mass of venom protein to account for yield differences between species.