Reading a colony: what an inspection can and cannot tell you
An inspection answers five questions — is there a laying queen, is the brood healthy, is there food, is there space, is the colony preparing to swarm — and every answer is a reading of signs that can mean more than one thing.
What an inspection is for
Opening a hive costs the colony heat, time and some temper, so an inspection should have questions. In the active season they are nearly always the same five: is there a laying queen, is the brood healthy, does the colony have enough food, does it have enough space, and is it preparing to swarm. A sixth runs underneath all of them: is there anything here that must be reported?
None of these is answered by a single sight. Eggs show a queen was laying three days ago, not that she is good. A patchy brood pattern has half a dozen causes. Queen cells can mean swarming, supersedure or an emergency. The useful habit is to treat each observation as the start of a chain — what it can mean, what it cannot tell you, what to look at next — rather than as a verdict.
Is there a laying queen?
The queen herself is the hardest thing in the hive to find and the least necessary to see. Her work is easier: single eggs standing in the bottom of cells, larvae of every age around them, and capped worker brood in a compact area say that a queen was laying within the last few days. Queen cells, and where they are on the comb, say what the colony is planning to do about her.
| What you see | What it can mean | What it cannot tell you | Next question |
|---|---|---|---|
| Single eggs standing upright in the bottom of worker cells | A queen laid here within about the last three days — eggs hatch after three. | Whether she is still there, how old she is, or how well she mated. An egg is a time-stamp, not a quality score. | Are there larvae of every age and capped worker brood in a compact area?. |
| No eggs and no young larvae during the active season | The queen has been lost or killed. Or: A new queen has not started laying yet. Or: A pause in laying, such as during a dearth or after a swarm has left. | Whether the colony is queenless: a virgin queen is small, fast and lays nothing, so a colony can look queenless when it is not. | Are there queen cells, open at the tip or torn down? Is the colony louder or more defensive than usual?. |
| Several eggs in one cell, some stuck to the cell walls | Laying workers, in a colony that has been without a queen and without young brood to raise a replacement. Or: Another queen problem: the NBU lists multiple eggs per cell among the field signs of one. | On its own, whether any queen is present. | Is drone brood appearing in worker cells, scattered and irregular?. |
| Domed drone cappings in worker-sized cells, scattered among the worker brood | A queen who has run out of sperm or was poorly mated, now laying only unfertilised eggs. Or: Laying workers, whose pattern is usually less compact. | Which of the two, without finding the queen or seeing how the eggs are laid. | Can the queen be found? Are the eggs single and centred, or several to a cell?. |
| One or a few queen cells on the face of a comb, with a laying queen present | Supersedure: the colony is replacing its queen. Or: The start of swarm preparation. | Why the colony is replacing her. Age, injury and failing pheromone output are all possible, and position on the comb is a tendency, not a rule. | How many cells are there, where are they, and how crowded is the colony?. |
Observations suggest questions; none of them is a diagnosis. Where a sign can point at a notifiable disease the table says so, and the deciding step is a test or a report, not more reading of comb.
Checked 2026-10-30 against: The Biology of the Honey Bee (Harvard University Press, 1987); Foulbrood disease of honey bees and other common brood disorders (National Bee Unit, Animal and Plant Health Agency, 2025).
Reading the brood
Brood is where most problems show first, and where it is easiest to read too much. A compact sheet of capped worker brood with pearly white larvae around it is reassuring but not a clean bill of health. A patchy, 'pepper-pot' pattern is a signal that something is removing or killing brood, and it can be a dozen things — including a perfectly good queen in a colony with a problem.
| What you see | What it can mean | What it cannot tell you | Next question |
|---|---|---|---|
| Capped worker brood in a compact area, with few empty cells | A laying queen, and a colony able to rear what she lays. | That the queen is young or well mated, or that the colony is free of disease. A good pattern is not a clean bill of health. | Are the larvae pearly white, plump and curled in a C?. |
| Patchy, 'pepper-pot' capped brood, with many empty cells scattered through the capped area | Dead brood removed by nurse bees. EFB, AFB, sacbrood, chalkbrood and varroa damage can all cause this. Or: Hygienic bees removing sick or mite-infested brood. Or: A queen laying eggs that do not develop. Or: The colony's environment: in one study, comb carrying more pesticide types went with poorer patterns. | Which of these it is. Researchers call a pattern poor when about a fifth or more of sealed cells are empty. Yet queens moved from poor-brood colonies into good ones laid good patterns within three weeks, so the pattern measures the colony as much as the queen. | Look into the empty and the capped cells. Are any cappings sunken, greasy or perforated? Are larvae discoloured, twisted or melted? Are there chalk-like mummies?. Stop and report if: Sunken or perforated cappings, discoloured or melted larvae, or cell contents that draw out in a rope can mean foulbrood. In the UK, suspected EFB or AFB must be reported to the National Bee Unit; elsewhere, report to the national bee-health authority. Confirmation comes from a field test or a laboratory, not from reading the pattern. |
| Larvae yellowed, twisted or 'melted' instead of pearly white and curled in a C | European foulbrood. Or: Sacbrood or another brood disorder. | Which disease it is. The signs overlap, and secondary bacteria change how dead larvae look. | Is it confined to a few cells or spread across the brood?. Stop and report if: Treat it as suspected foulbrood until shown otherwise: report it where reporting is required, and do not move combs or equipment between colonies. |
| Dead brood of all ages at the edges of the brood nest, turning dark brown or black | Chilled brood: too few adult bees to keep all the brood warm, after the population has fallen, the colony has been split, or a cold snap has made the cluster contract. | Why the population fell. Chilled brood is a disorder, not a disease, but it often follows one. | Has the colony lost bees recently, been split or been moved?. |
| Sealed cappings that are sunken, darkened, greasy-looking or pierced | American foulbrood. Or: European foulbrood. Or: Other brood dead under its cappings, such as sacbrood or brood killed by mites. | Which disease, or whether any is present. WOAH notes that patchy comb is not specific to American foulbrood, and a matchstick 'rope' test can be negative when the remains are watery. | How many cells are affected, and what do the remains inside look like?. What would settle it: A lateral flow device used by an inspector, or laboratory testing. Stop and report if: In the UK, suspected AFB or EFB must be reported to the bee inspectorate at once, and nothing moved from the apiary until it is allowed. Elsewhere, report to the national bee-health authority. |
Observations suggest questions; none of them is a diagnosis. Where a sign can point at a notifiable disease the table says so, and the deciding step is a test or a report, not more reading of comb.
Checked 2026-10-30 against: Is the brood pattern within a honey bee colony a reliable indicator of queen quality? (Insects, 2019); Foulbrood disease of honey bees and other common brood disorders (National Bee Unit, Animal and Plant Health Agency, 2025); Chapter 3.2.2. American foulbrood of honey bees (infection of honey bees with Paenibacillus larvae) (WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals); Honey bees: protecting them from pests and diseases (Department for Environment, Food & Rural Affairs; Animal and Plant Health Agency, 2024).
Food, pollen, space and population
Capped honey along the top and sides of the brood frames, bee bread in an arc around the brood, and a ring of empty comb for the queen to lay in are the shape of a colony that is fed and has room. Each of those can go wrong in both directions: too little food and the colony starves; too little space and nectar fills the brood nest, the queen is crowded and swarm preparation can begin.
| What you see | What it can mean | What it cannot tell you | Next question |
|---|---|---|---|
| The hive feels light when hefted in winter or early spring | Stores are running low, with starvation a risk once brood rearing restarts. | Where the remaining stores are. Hefting cannot detect isolation starvation, where the cluster is cut off from food in the same box. | On a mild day, is the cluster in contact with capped stores?. |
| Little or no stored pollen (bee bread) around the brood | A gap in pollen forage, from the weather or from a landscape with nothing flowering at the time. Or: Pollen being used as fast as it arrives during heavy brood rearing. | Whether nutrition is limiting the brood. A narrow diet can leave bees short even with pollen present, and colonies fed on a variety of pollen fare better than those fed on one. | Are pollen loads coming in at the entrance on flying days, and in more than one colour?. |
| Nectar stored in the brood nest, in cells the queen would otherwise lay in | A strong flow, with too little storage space elsewhere. Or: Reduced laying: the queen is slowing down, or the colony is preparing to swarm. | On its own, which of the two is driving it. | Is there empty drawn comb above the brood? Are there queen cups with eggs in them?. |
| A small adult population going into winter | A poor chance of surviving winter. Autumn colony size predicted survival better than the origin of the stock in one United States study. | Why it is small: disease, a queen problem, a late swarm or a poor season. | Is there disease or a queen problem? A colony is combined with another only once both are known to be free of disease. |
| A colony suddenly more defensive than usual | Queenlessness. Or: A dearth, with robbing pressure at the entrance. Or: Disturbance by predators. | Much on its own: temperament also changes with the weather and the stock. | Is there brood of every age? Are robbers or wasps working the entrance?. |
Observations suggest questions; none of them is a diagnosis. Where a sign can point at a notifiable disease the table says so, and the deciding step is a test or a report, not more reading of comb.
Checked 2026-10-30 against: Feeding sugar to bees (Best Practice Guideline No. 7a) (National Bee Unit, Animal and Plant Health Agency, 2026); Nutrition and health in honey bees (Apidologie, 2010); Influence of pollen nutrition on honey bee health: do pollen quality and diversity matter? (PLOS ONE, 2013); The Biology of the Honey Bee (Harvard University Press, 1987); Honeybee Democracy (Princeton University Press, 2010); Colony size, rather than geographic origin of stocks, predicts overwintering success in honey bees in the northeastern United States (Journal of Economic Entomology, 2019); Preparing honey bee colonies for winter (Fact Sheet 19) (National Bee Unit, Animal and Plant Health Agency, 2026); Foulbrood disease of honey bees and other common brood disorders (National Bee Unit, Animal and Plant Health Agency, 2025); Mite bombs or robber lures? The roles of drifting and robbing in Varroa destructor transmission from collapsing honey bee colonies to their neighbors (PLoS ONE, 2019).
Temperament, drones, comb and pests
- Temperament: a colony that is suddenly more defensive is telling you something — queenlessness, robbing pressure or predators — though weather and stock change temper too.
- Drones: drone brood in drone comb at the edges of the brood nest is normal in the active season. Drone brood in worker cells, scattered among the worker brood, is not.
- Comb: old, dark comb carries more disease spores and residues than new comb; replacing brood comb over time is a standard hygiene measure against brood disease.
- Pests: mites on adult bees or on the floor, bees with deformed wings, and patches of uncapped or dead pupae are the field signs of a heavy varroa load and of the viruses it carries.
Adult bees, the entrance and the comb
Some of the most telling signs are not on the brood at all: bees crawling with crumpled wings, bees trembling at the entrance, dead bees piled outside one hive, hornets waiting in front of it, slime or silk in the comb. They follow the same rule as the brood. Each can mean more than one thing, and where one points at something notifiable the table says to stop and report.
| What you see | What it can mean | What it cannot tell you | Next question |
|---|---|---|---|
| Bees with crumpled, shrivelled wings crawling on the comb or at the entrance | Deformed wing virus, driven up by a heavy varroa load. Or: Parasitic mite syndrome, if the brood is also patchy with uncapped, dying pupae. | How many mites the colony carries. By the time deformed wings are easy to find, the load is usually already high. | What does a measured mite count show?. What would settle it: A mite count: an alcohol wash, a sugar roll or natural mite fall. |
| Trembling bees that cannot fly, some hairless, black and shiny | Chronic bee paralysis. Or: Poisoning, which also leaves trembling and dying bees. | Which of these it is. The virus is also common at low levels in colonies without disease, so even a positive test is not the whole answer. | Are the dead bees piled at one hive's entrance, or spread across the apiary?. What would settle it: Laboratory testing of a sample of affected bees. |
| Brown faecal streaks on the comb and the front of the hive | Nosemosis, in some acute Nosema apis cases. Or: Dysentery with another cause. | Whether Nosema is present. Most infected colonies show no sign at all, and the spores can be seen only under a microscope. | Has the colony been confined for a long spell?. What would settle it: Spores under a microscope at ×400; PCR to tell the two species apart. |
| Many dead bees at or in front of the hive | Piles at one hive's entrance: chronic bee paralysis is one cause. Or: Carpets of dead bees across the whole apiary: the National Bee Unit's pointer towards poisoning. | The cause. The difference between piles and carpets is a pointer, not a test. | Is it one colony or many? If poisoning is suspected, the national authority is the place to ask. |
| Hornets hovering in front of the entrance, taking returning foragers | Yellow-legged hornets hawking. Or: The native European hornet, which is larger and browner. | Which species it is, without a clear view or a photograph. A mistaken report, or a native hornet killed on suspicion, has a cost too. | Are the legs yellow at the ends, and the body almost black with one orange band?. What would settle it: A photograph verified by the authority. Stop and report if: Where the yellow-legged hornet is a reportable sighting, report it with a photograph — in the UK, through the Asian Hornet Watch app. Never approach a nest. |
| Foragers staying in on a fine day while hornets wait outside | Foraging paralysis under hornet pressure, which can weaken a colony before predation does. | What it costs the honey crop. The study behind it measured colony development, not yield. | Is pollen still coming in? Is the brood area shrinking?. |
Observations suggest questions; none of them is a diagnosis. Where a sign can point at a notifiable disease the table says so, and the deciding step is a test or a report, not more reading of comb.
Checked 2026-10-30 against: Chapter 3.2.7. Varroosis of honey bees (infestation of honey bees with Varroa spp.) (WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, 2021); Foulbrood disease of honey bees and other common brood disorders (National Bee Unit, Animal and Plant Health Agency, 2025); Chronic bee paralysis: an information note for beekeepers (Fact Sheet 10) (National Bee Unit, Animal and Plant Health Agency, 2024); Chronic bee paralysis as a serious emerging threat to honey bees (Nature Communications 11:2164, 2020); Chapter 3.2.4. Nosemosis of honey bees (WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, 2024); Yellow-legged hornet: status, monitoring and reporting (BeeBase) (Animal and Plant Health Agency, National Bee Unit, 2026); DAERA issues fresh appeal for public vigilance over Asian hornet sightings (Department of Agriculture, Environment and Rural Affairs (Northern Ireland), 2026); Effectiveness of electric harps in reducing Vespa velutina predation pressure and consequences for honey bee colony development (Pest Management Science, 2022).
| What you see | What it can mean | What it cannot tell you | Next question |
|---|---|---|---|
| Slime on the comb, honey frothing or smelling fermented, larvae in the comb | Small hive beetle larvae. | Whether it is the beetle, without a specimen identified by the authority. | Are there small dark beetles running from the light?. What would settle it: A specimen identified by the national authority. Stop and report if: In the UK the beetle is notifiable: report a suspicion at once and move no colonies, equipment or honey. Elsewhere, report to the national bee-health authority. |
| Silk webbing and tunnels through comb, cocoons pressed into the woodwork | Wax moth larvae, opportunists that thrive in stored comb and weak colonies. | Why the colony could not defend its comb. Wax moth usually follows weakness rather than causing it. | Is the colony strong enough for the space it has?. |
| Lines of uncapped pupae running across the comb | Wax moth larvae tunnelling under the cappings: bald brood. | On its own, that the brood is healthy. | Are the pupae plump and the cell edges smooth and raised, or ragged with unhealthy pupae?. |
| Hard white, grey or black 'mummies' in cells, on the floor or at the entrance | Chalkbrood. | Why the colony is susceptible. Chilled brood and a small population play a part, and hygienic behaviour did not predict it in one Australian survey. | Is the colony small for its brood, or has the weather been cold?. |
| Small, fast-moving reddish-brown mites on the brood comb | Tropilaelaps. Or: Varroa, which is larger, wider than long and slow. Or: Harmless mites that live in hives. | Which mite it is, without a lens and a specimen. | Is the mite longer than it is wide, and does it run?. What would settle it: A specimen identified under the microscope and by PCR. Stop and report if: In the UK, suspected Tropilaelaps is notifiable and must be reported at once. Elsewhere, report to the national bee-health authority. |
Observations suggest questions; none of them is a diagnosis. Where a sign can point at a notifiable disease the table says so, and the deciding step is a test or a report, not more reading of comb.
Checked 2026-10-30 against: Chapter 3.2.5. Infestation of honey bees with Aethina tumida (small hive beetle) (WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, 2018); Honey bees: protecting them from pests and diseases (Department for Environment, Food & Rural Affairs; Animal and Plant Health Agency, 2024); The biology and control of the greater wax moth, Galleria mellonella (Insects, 2017); Foulbrood disease of honey bees and other common brood disorders (National Bee Unit, Animal and Plant Health Agency, 2025); Hygienic behaviour selection via freeze-killed honey bee brood not associated with chalkbrood resistance in eastern Australia (PLOS ONE, 2018); Chapter 3.2.5. Infestation of honey bees with Tropilaelaps spp. (WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, 2018); Tropilaelaps: parasitic mite of honey bees (advisory leaflet) (Animal and Plant Health Agency, National Bee Unit, 2026).
Keeping a colony record
A single inspection is a snapshot; most of what matters is a trend. A colony that has had eggs at every visit and a compact brood pattern, and then has neither, is a different problem from one that never had either. A short record kept at every inspection is what turns the five questions into a history.
| Record | Why it matters |
|---|---|
| Date and weather | Timing and temper both depend on the weather; trends are read against dates |
| Queen: seen, eggs, age, origin | Queen problems show as a change from the last visit, not as a single sign |
| Brood: how many frames, pattern, anything abnormal | A falling brood area or a new abnormality is the earliest warning |
| Food and pollen: frames or weight | Starvation is predictable from a falling trend |
| Space: supers added or removed | Links swarm preparation and honey yield to what was done |
| Queen cells: number, position, open or sealed | Tells a beekeeper how much time is left before a swarm |
| Temper | A sudden change is a symptom |
| Disease and pest signs, mite counts | Treatment decisions need numbers, and authorities ask for history |
| Treatments: product and dates | Required in some jurisdictions; check what yours asks for |
| Feeding, harvest, swarms, requeening | The colony's year, in one place |
| Winter outcome | Whether the colony survived, and in what state, is the test of everything above |
When to stop interpreting
Some signs are not puzzles to be solved at the hive. Suspected foulbrood, an unfamiliar beetle or mite, and anything a national authority lists as notifiable go to that authority, which can test what an inspection can only suspect. Reporting is a legal duty in many countries and the reason the diseases that are rare there have stayed rare.
Sources
- Foulbrood disease of honey bees and other common brood disorders — National Bee Unit, Animal and Plant Health Agency (2025) · Regulatory guidance Link
- Is the brood pattern within a honey bee colony a reliable indicator of queen quality? — Insects (2019) · Peer-reviewed article Link
- Preparing honey bee colonies for winter (Fact Sheet 19) — National Bee Unit, Animal and Plant Health Agency (2026) · Regulatory guidance Link
- Swarm control when you can't find the queen (Fact Sheet 24) — National Bee Unit, Animal and Plant Health Agency (2019) · Regulatory guidance Link
- The Biology of the Honey Bee — Harvard University Press (1987) · Textbook
- Nutrition and health in honey bees — Apidologie (2010) · Peer-reviewed article Link
- Chapter 3.2.2. American foulbrood of honey bees (infection of honey bees with Paenibacillus larvae) — WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals · Standards document Link
- Chapter 3.2.7. Varroosis of honey bees (infestation of honey bees with Varroa spp.) — WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals (2021) · Standards document Link
- Chapter 3.2.4. Nosemosis of honey bees — WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals (2024) · Standards document Link
- Chapter 3.2.5. Infestation of honey bees with Aethina tumida (small hive beetle) — WOAH Manual of Diagnostic Tests and Vaccines for Terrestrial Animals (2018) · Standards document Link
- Chronic bee paralysis: an information note for beekeepers (Fact Sheet 10) — National Bee Unit, Animal and Plant Health Agency (2024) · Regulatory guidance Link
- The biology and control of the greater wax moth, Galleria mellonella — Insects (2017) · Peer-reviewed article Link
- HoneyHQ editorial synthesis — HEKNO Ltd · HoneyHQ synthesis
How sources are selected and weighted is set out in the sources and evidence policy.
Read next
- The queen bee explainedQueen biology, failure and replacement.
- Why bees swarm, and what to do if you see oneSwarm preparation and the principles of swarm control.
- The bee year: three timetables running at onceWhich phase of the year the colony is in changes what an inspection means.
- Foulbrood and the notifiable bee diseasesFoulbrood and the notifiable diseases, and how they are reported.
- Varroa and the health of a honey bee colonyMonitoring and managing the mite.
- How honey bees survive winterStores, population and winter checks.
- Brood diseases: telling foulbrood from its look-alikesThe brood diseases and disorders, side by side, and what confirms each.
- Honey bee viruses: why finding one is not finding diseaseCrawling, trembling and crippled bees, and the viruses behind them.
- Small hive beetle and wax moths: the comb scavengersSlime, silk and tunnels in the comb.
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