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Paralysis efficiency (PD50) scales linearly with lethality (LD50) in spider venoms
Keith Lyons1,2,3, Dayle Leonard2, Leona McSharry2
1Macroecology Lab, School of Natural Sciences, Ryan Institute, University of Galway, H91 TK33, Galway, Ireland.
Toxicon: X
|May 6, 2026
Summary
Historically, venom potency was measured by lethality (LD50), but incapacitation (PD50) might be more ecologically relevant. This study found a strong correlation between LD50 and PD50 in spider venoms, suggesting LD50 can still be a useful proxy for general venom potency.
Area of Science:
- * Zoology and Toxinology
- * Evolutionary Biology
Background:
- * Traditional venom potency assessments rely on median lethal dose (LD50), which may not reflect ecological efficacy.
- * Median paralysis dose (PD50) offers a more ecologically relevant measure of venom's incapacitating effects.
- * The relationship between LD50 and PD50 in spider venoms requires clarification to validate historical data.
Purpose of the Study:
- * To investigate the correlation between median lethal dose (LD50) and median paralysis dose (PD50) in spider venoms.
- * To determine if LD50 values can serve as reliable proxies for ecologically relevant venom potency.
Main Methods:
- * Experimentally determined LD50 and PD50 for 12 spider species.
- * Compiled existing LD50 and PD50 data from literature for an additional 46 species.
- * Analyzed a combined dataset of 55 species across 26 families.
Main Results:
- * A significant linear isometric relationship was observed between LD50 and PD50 values.
- * Increased venom paralysis efficiency strongly correlated with increased venom lethality.
- * The findings indicate that lethality and paralysis are functionally linked aspects of venom potency.
Conclusions:
- * Historically measured LD50 values remain useful for comparing general spider venom potencies.
- * This utility is contingent upon the use of consistent prey models for LD50 determination.
- * The strong correlation validates the use of LD50 as a proxy when PD50 data is unavailable.
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