Blacklegged ticks, Ixodes scapularis, reduce predation risk by eavesdropping on communication signals of Formica oreas thatching ants

Ticks spend most of their life inhabiting leaf litter and detritus where they are protected from sun but preyed upon by ants. Ants secrete chemical communication signals to coordinate group tasks such as nest defense. Ticks that avoid ant semiochemicals – as indicators of ant presence – would reduce predation risk by ants. We tested the hypotheses that (1) chemical deposits from the thatching ant Formica oreas deter blacklegged ticks, Ixodes scapularis, (2) deterrent semiochemicals originate from the ants’ poison and/or Dufour’s gland(s), and (3) tick-deterrent semiochemicals serve as alarm-recruitment pheromone components in F. oreas. In two-choice olfactometer bioassays, filter paper soiled with ant chemical deposits significantly deterred female and male ticks. Poison and Dufour’s gland extracts deterred ticks in combination but not alone. Gas chromatographic-mass spectrometric analyses of gland extracts revealed formic acid as the major constituent in the poison gland and 8 hydrocar..., , , # Blacklegged ticks, *Ixodes scapularis*, reduce predation risk by eavesdropping on communication signals of Formica oreas thatching ants

**Experiment Descriptions:**
1. Exp1 - Female blacklegged ticks, *Ixodes scapularis*, responding in olfactometers to filter paper previously soiled (treatment), or not (control), with chemical deposits of 20 Formica oreas worker ants
2. Exp2 - Male blacklegged ticks, *Ixodes scapularis*, responding in olfactometers to filter paper previously soiled (treatment), or not (control), with chemical deposits of 20 Formica oreas worker ants
3. Exp3 - Female blacklegged ticks, *Ixodes scapularis*, responding in olfactometers to *Formica oreas* poison gland extract (treatment) or dichloromethane (solvent control)
4. Exp4 - Male blacklegged ticks, *Ixodes scapularis*, responding in olfactometers to *Formica oreas* poison gland extract (treatment) or dichloromethane (solvent control)
5. Exp5 - Female blacklegged ticks, *Ixodes scapularis*, responding in olfact...