Around 6 to 8 per cent of flowering plants lock their pollen inside tubes that open through a single pore, and release it only to a bee that grips the flower and vibrates. Honey bees cannot do it, which is why tomatoes are pollinated by bumblebees.
PollinationReviewed 2026-10-31
The flower's side of it
Most anthers split lengthwise and present pollen on an open surface, where any visitor can collect it and a good deal is lost to wind and to visitors that do nothing useful in return. A poricidal anther does not split. It stays closed and opens only through a small pore at the tip, holding the pollen inside like salt in a shaker.
This is a control mechanism. The plant is metering its pollen out to visitors capable of a specific behaviour, which raises the proportion delivered to another flower of the same species rather than eaten or wasted. The families that do it most are the nightshades, the heathers and blueberries, the melastomes and a scattering of others — somewhere around 20,000 species in total.
The bee's side of it
1GripThe bee lands and curls around the anther cone, holding on with its mandibles and legs. This part is visible and looks like wrestling.
2Decouple and vibrateIt uncouples its flight muscles from its wings and contracts them rapidly — often several hundred times a second — transmitting the vibration through its body into the anther. The wings stay largely still, which is why a buzz-pollinating bee sounds different from a flying one.
3CollectPollen sprays out of the pore onto the bee's body and is groomed into the scopa or corbicula. The whole event takes a second or two, and a bee will repeat it on flower after flower.
Buzz pollination, in three panels. First: a poricidal anther holds its pollen inside and opens only by a small pore at the tip. Second: a bumblebee or another buzz-capable bee grips the flower and vibrates its flight muscles without flapping its wings; the vibration shakes pollen out of the pore onto the bee, which carries it to the next flower. Third: a honey bee cannot vibrate the flower this way, so it releases much less — though it can still collect pollen shaken loose by other bees, and in cages with nothing else to forage on honey bees have collected blueberry pollen unaided. Buzz-capable bees are not all equally effective either. Sources: Pollination of blueberry crops in Pennsylvania; Who pollinates Pennsylvania blueberry plants?; Do buzz-pollinating bumble bees facilitate honey bee pollination in southern highbush blueberry through increasing pollen release?. Drawing: HoneyHQ (HEKNO Ltd), original.
Why honey bees cannot
Honey bees do not perform sonication. They visit poricidal flowers and collect what has already been shaken loose by other visitors or by wind, which makes them poor pollinators of these species rather than useless ones. It is the clearest single case of the honey bee not being a general-purpose substitute for wild bees.
On blueberry the difference has been measured. Penn State reports an average of about 11 pollen grains left on the stigma per honey bee visit, against 43 for bumble bees and 49 for mining bees. Yet 'cannot buzz' is not 'cannot collect': in a 2026 caged experiment in Florida with nothing else to forage on, honey bees released and gathered southern highbush blueberry pollen on their own, and the presence of bumble bees did not raise their pollen loads. Large blueberry farms still rent honey bee colonies for their numbers, and Penn State's view is that honey bees alone are not enough for the best yields.
The same fact runs through the plant lists on this site. Blueberry, cranberry and bilberry are buzz-pollinated; in Australia a large share of the native flora is; and in the Neotropics Melipona are among the significant buzz pollinators, which is one reason stingless bees matter agriculturally there.
What this means for a garden
If you grow tomatoes, aubergines or peppers, the pollinator you need is a bumblebee or a solitary buzz pollinator — not a hive.
Blueberries crop measurably better where wild bees are present, and a hive alone does not substitute.
Bare undisturbed ground and undisturbed stems matter here, because the bees that do this are mostly solitary.
In a garden, a hive adds little for these crops: the visits that count are the buzzing ones. Commercial blueberry growing is different — there honey bees are rented for sheer numbers, alongside the wild bees that buzz.
The claims on this page
Every substantive claim is placed on a tier, and the top two tiers must also state what they are not claiming.
Established evidence
Supported by systematic reviews, meta-analyses or clinical/regulatory guidance. The claim would survive a careful reader checking it.
Established evidence
Honey bees do not perform buzz pollination, and commercial bumblebee colonies are used to pollinate glasshouse tomatoes for that reason.
Sonication is absent from the honey bee behavioural repertoire and well documented in bumblebees, carpenter bees and many solitary genera. The commercial rearing of Bombus for glasshouse tomato pollination, which replaced mechanical hand-pollination from the late 1980s, is the applied consequence and is described in the pollination assessment literature.
What this does not claim: This is not a claim that honey bees never visit poricidal flowers or contribute nothing at them — they collect loose pollen and can effect some transfer. Nor is it a claim that buzz pollination is required for a crop to set at all; several buzz-pollinated crops will self-pollinate at reduced rates without it.
Assessment Report on Pollinators, Pollination and Food Production — Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) (2016) · Systematic reviewLink
Sources
Assessment Report on Pollinators, Pollination and Food Production — Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) (2016) · Systematic reviewLink
Bumblebees: Behaviour, Ecology, and Conservation — Oxford University Press (2010) · Monograph
Pollination of blueberry crops in Pennsylvania — Penn State Extension (M. López-Uribe, K. Demchak, S. Fleischer and others) (2025) · Field guideLink
Who pollinates Pennsylvania blueberry plants? — Penn State Extension (M. López-Uribe, S. Fleischer, K. Watrous, N. Amon) (2026) · Field guideLink
Do buzz-pollinating bumble bees facilitate honey bee pollination in southern highbush blueberry through increasing pollen release? — Ecology and Evolution 16(3): e73208 (2026) · Peer-reviewed articleLink
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