Short-lived ants take greater risks during food collection

Area of Science:

• Behavioral Ecology
• Evolutionary Biology
• Social Insect Behavior

Background:

• Life-history theory posits that organisms adjust behavior in response to declining life expectancy.
• Worker life expectancy is a critical factor in task allocation for risk-related activities in social insects.
• A core prediction is that individuals with shorter life expectancies undertake riskier tasks.

Purpose of the Study:

• To empirically test the hypothesis that shorter-lived insect workers perform riskier tasks.
• To investigate the relationship between worker life expectancy and risk-taking behavior in foraging ants.
• To determine if ant foraging strategies are modulated by perceived life expectancy.

Main Methods:

• Laboratory colonies of the ant *Myrmica scabrinodis* were utilized.
• Foraging risk was manipulated by altering patch distances, temperatures, and competitor presence.
• Worker life expectancy was experimentally reduced using carbon dioxide poisoning or propodeal spine removal.

Main Results:

• Both carbon dioxide poisoning and propodeal spine removal significantly reduced worker ant life expectancy compared to controls.
• Ants with experimentally shortened life expectancies exhibited a higher propensity to forage under risky conditions.
• This provides the first empirical evidence that foraging under risk is directly influenced by worker life expectancy.

Conclusions:

• Worker ant foraging behavior is demonstrably fine-tuned to their individual life expectancy.
• The study supports evolutionary models predicting adaptive behavioral adjustments based on lifespan in social insects.
• This adaptive strategy optimizes resource acquisition and colony survival under varying environmental and internal conditions.