Detection Manual — Field Guide
A practical, beekeeper‑friendly method for early varroa stress detection using hive acoustics.
Introduction
This Field Guide provides a simple, repeatable method for detecting early varroa‑related stress through short acoustic recordings taken at three specific times of day. These windows reveal subtle physiological changes long before visual symptoms appear, giving beekeepers a reliable early‑warning system that fits naturally into weekly hive care.
1. Purpose of the Field Guide
This manual is designed to help beekeepers:
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capture consistent acoustic snapshots
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recognise early stress indicators
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compare recordings week‑to‑week
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build a clear picture of colony resilience
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detect varroa‑related strain before brood or adult symptoms appear
It focuses on practical field use: short recordings, simple observations, and clear signs.
2. Why These Recording Windows Work
Honey bee colonies follow strong daily rhythms. Varroa disrupts these rhythms — but only certain times of day reveal the disruption clearly.
The three windows below were chosen because they expose different physiological states:
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Early Morning — overnight recovery
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Mid‑Morning — peak brood‑care stability
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Night — deep metabolic health
Together, they form a complete acoustic health profile.
3. The Three Recording Windows
Early Morning (around 6:30 am)
Shows overnight recovery and baseline strength.
Healthy colonies:
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steady fundamental hum
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smooth warm‑up curve
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stable brood‑temperature tone
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clean harmonic formation
Early stress indicators:
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delayed warm‑up
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weak fundamentals
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sluggish harmonics
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“tired” tone quality
Mid‑Morning (9:30–11:30 am)
The primary diagnostic window.
Healthy colonies:
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strong WorkEngine
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clear harmonic ladder
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dense midband activity
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stable brood‑care rhythms
Early stress indicators:
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60 Hz mismatch
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midband thinning
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UMB thinning
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harmonic fray
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brood‑load strain
Night (9–10 pm)
Shows deep metabolic stability.
Healthy colonies:
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strong, steady fundamental
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clean harmonics
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stable brood‑temperature tone
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minimal behavioural noise
Stress indicators:
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fundamental sag
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harmonic collapse
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ventilation scatter
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“tired” night hum
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agitation bursts
4. The Seven Acoustic Signs of Varroa Stress
1. 60 Hz Mismatch
Misalignment between the fundamental and its harmonic multiples — the earliest and most reliable indicator.
2. Upper‑Midband (UMB) Thinning
Weakening of the upper midband — early nurse‑bee fatigue.
3. Structural Drift
Slow, unstable shifts in the hive’s acoustic structure — coordination strain and thermoregulation instability.
4. Fundamental Sag
A heavy, unstable, “tired” fundamental — deeper metabolic stress.
5. Harmonic Fray
Loss of clarity in harmonic multiples — weakening thoracic muscle output.
6. Ventilation Scatter
Irregular, messy ventilation tones — internal regulation strain.
7. Agitation Bursts
Short spikes of chaotic energy — especially concerning at night.
5. Weekly Acoustic Checklist
Early Morning (6:30 am)
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Record 30–60 seconds
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Note weather
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Check for fundamental heaviness or weak harmonics
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Save spectrogram
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Write brief notes
Mid‑Morning (9:30–11:30 am)
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Record 30–60 seconds
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Look for mismatch, thinning, fray
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Save spectrogram
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Write notes
Night (9–10 pm)
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Record 30–60 seconds
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Look for sag, scatter, agitation
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Save spectrogram
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Write notes
Weekly Summary
Mark hive status: Stable / Early Stress / Mid‑Stage / Late‑Stage
6. Notes for Future Refinement
Future editions will expand on tone families, seasonal variation, severity grading, and cross‑hive comparisons.
7. Intellectual Property Statement
This document, including the acoustic detection method, timing system, diagnostic indicators, and interpretive
framework, is original work based on my own hive recordings and observations. All written content and the
structure of the method are protected under copyright. This Field Edition may be shared for non-commercial
use, but it may not be republished, reproduced, or incorporated into commercial training or publications without
permission.