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Bacteriolytic activity in the ejaculate of an insect.
Oliver Otti1, Richard A Naylor, Michael T Siva-Jothy
1Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom. o.otti@sheffield.ac.uk
The American Naturalist
|June 25, 2009
Summary
Male bedbugs ejaculate contains bacteriolytic activity (lysozyme-like immune activity [LLA]), suggesting sperm-microbe interactions drive ejaculate evolution through natural selection.
Area of Science:
- Evolutionary biology
- Reproductive biology
- Immunology
Background:
- Sexual selection is a primary driver of ejaculate evolution.
- The interaction between sperm and microorganisms is often overlooked.
- There is a need to understand factors protecting ejaculates from microbial threats.
Purpose of the Study:
- To investigate the presence of protective substances in animal ejaculate.
- To explore the role of natural selection in ejaculate component diversity.
- To report bacteriolytic activity in the common bedbug (Cimex lectularius) ejaculate.
Main Methods:
- Assessing ejaculate for bacteriolytic activity (lysozyme-like immune activity [LLA]).
- Comparing LLA levels in seminal fluid and hemolymph.
- Testing for antimicrobial peptide activity in seminal fluid.
Main Results:
- Bacteriolytic activity (LLA) was detected in the ejaculate of Cimex lectularius for the first time.
- In nearly half of males, seminal fluid LLA surpassed hemolymph LLA.
- No antimicrobial peptide activity was found in the seminal fluid.
Conclusions:
- Sperm-microbe interactions are likely significant in ejaculate evolution.
- Natural selection may explain the diversity of seminal components via antimicrobial defenses.
- Lysozyme-like immune activity represents a key defense mechanism in ejaculate.
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