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The venom optimisation hypothesis: a spider injects large venom quantities only into difficult prey types
Esther Wigger1, Lucia Kuhn-Nentwig, Wolfgang Nentwig
1Zoological Institute, University of Bern, Baltzerstr. 6, 3012 CH Bern, Switzerland.
Summary
The spider Cupiennius salei conserves venom by injecting minimal amounts into vulnerable prey. It injects more venom into dangerous prey, supporting the venom optimization hypothesis for spiders.
Area of Science:
- Arachnology
- Animal Behavior
- Biochemistry
Background:
- The spider Cupiennius salei possesses limited venom reserves (10 microliters) and slow venom gland regeneration (8-16 days).
- Efficient venom utilization is crucial for spider survival and predation success.
Purpose of the Study:
- To quantify the venom dosage injected by Cupiennius salei into various prey types.
- To test the venom optimization hypothesis, which posits economical venom use by spiders.
Main Methods:
- Development and application of a monoclonal antibody for precise measurement of injected venom.
- Comparative analysis of venom quantities injected into prey with differing defense mechanisms (crickets, stick insects, blowflies, ground beetles).
Main Results:
- Prey lacking defense mechanisms (crickets, stick insects) received minimal venom doses, near the LD(50).
- More dangerous prey (blowflies, ground beetles) elicited significantly higher venom injections.
- These findings demonstrate a prey-dependent venom injection strategy in C. salei.
Conclusions:
- Cupiennius salei adjusts venom expenditure based on prey type and defensive capabilities.
- The study provides strong evidence supporting the venom optimization hypothesis in spiders.
- This research highlights the sophisticated predatory strategies employed by spiders to conserve vital resources.