Immune function trade-offs in response to parasite threats

Area of Science:

• Ecology
• Evolutionary Biology
• Immunology

Background:

• Immune function involves energetic costs and physiological trade-offs.
• Animals may allocate resources to immune factors based on parasite-driven fitness costs.
• Immune trade-offs are context-dependent, often exacerbated by resource limitation or stress.

Purpose of the Study:

• To investigate how humoral and cellular immune factors differ between cricket phenotypes.
• To determine the influence of physiological stress on these immune factors.
• To explore potential trade-offs between humoral and cellular immunity.

Main Methods:

• Measured constitutive lysozyme activity (humoral immunity) and encapsulation response (cellular immunity) in wing dimorphic crickets.
• Subjected crickets to physiological stress using a sham predator in a full factorial design.
• Analyzed immune factor variation between morphs and in response to stress.

Main Results:

• Immune strategies correlated with the selective pressures faced by each cricket morph.
• Physiological stress significantly decreased encapsulation response but did not affect lysozyme activity.
• Findings suggest a potential trade-off between humoral and cellular immunity.

Conclusions:

• Immune factor allocation is influenced by morph-specific selective pressures.
• Stress can modulate immune responses, potentially favoring humoral over cellular immunity.
• Parasite pressure may drive insect polyphenism through disruptive selection on immune strategies.