How Big Is The Brain Of A Bee?

Bees may be small, but they are known for being smart.  Bees have been trained to navigate mazes, sniff out bombs and more. 

This may lead use to ask, how big is a bee's brain?  

We measure tiny bee brains by weight, and the answer is, not surprisingly, it depends on the size and species of bee. 

However, from research, we know that:

At the other end of the scale are some of the base-banded furrow bees (Lassioglossum) and the yellow-face bees (Hylaeus), which have brains that weigh less than half a milligram.

Below, this topic is explored in greater detail, looking at the recorded brain sizes of 93 species of bee.

How Big Is A Bee Brain? 
Which Bee Has The Largest / Smallest Brain?

Unless we measure the brain of every single bee in the world, we cannot be sure which bee has the largest brain, although we could hazard a reasonable guess that the biggest bee brain probably belongs to the world's largest known bee species, Megachile pluto, Wallace's giant bee.   

However, I'm not aware of any research data providing the weight of its brain, and I wouldn't want to hear of any new research in which this species was dissected just to find out - they are rare!

Likewise, the bees with the tiniest brains are quite likely to be the world's smallest bees, currently believed to be Perdita minima and Quasihesma clypearis.

Are bees with larger brains more clever than bees with smaller brains?

This may or may not be true.  For example one study showed that large bumble bee workers are more efficient foragers and are better learners than their smaller sisters.

However, we cannot know for sure whether a bumble bee species with a larger brain than a honey bee, is therefore always smarter (according to the limits of any experiment humans could devise to answer the question).  In fact, there is  plenty of research assessing the ability of honey bees in particular to learn concepts, recognize, remember, among other skills - see Are Bees Smart? 

In comparison, there is little research testing the intelligence of other bees.

In any event, with so many species in the world, we cannot possibly make generalizations and comparisons for all bees, based only on what we know about one species.

What we do know about the size of bee brains...

However, we know the sizes of brains of 93 different bee species, thanks to a piece of research in which this data was collected. 

From that particular study, the smallest was the brain of Lasioglossum sexstrigatum, the Fringed furrow bee, with a brain weighing 0.23mg, and the largest was that of the Carpenter bee, Xylocopa valga with a brain weighing 7.43mg.

The full tables of data for the 93 bees are provided further down this page, however, it's probably worth summarizing some of the information into key points. 

Largest bee brains

Of the 93 species studied, the top 5 bees with the largest brains were mostly the large carpenter bees, Xylocopa, along with one other species, the Florentine wool carder:

Species	Common Name	Brain Size (mg)
Xylocopa valga	Carpenter Bee	7.43
Xylocopa violacea	Violet Carpenter Bee	5.876
Xylocopa virginica	Eastern Carpenter Bee	5.438
Xylocopa cantabrita	Cantabrian Carpenter Bee	4.968
Anthidium florentinum	Florentine Wool Carder Bee	4.46

However, when we consider the size of the brain in proportion to the body, the White-banded digger bee enters the top 5.

Species	Common Name	Body Size ITS (mm)	Brain Size (mg)	Brain mg /mm
Xylocopa valga	Carpenter Bee	7.024	7.43	1.058
Anthidium florentinum	Florentine Wool Carder Bee	4.254	4.46	1.048
Amegilla quadrifasciata	White-banded digger bee	3.849	3.926	1.020
Xylocopa virginica	Eastern Carpenter Bee	5.518	5.438	0.986
Xylocopa violacea	Violet Carpenter Bee	6.095	5.876	0.964

Bee brain size grouped by genus (type)

I grouped some (but not all) of the species by commonly-known type (genus). 

For example, I grouped all of the bumble bees in the study together, and separately, the leafcutters etc, and looked at the range in sizes, just for comparison. (There is some slight rounding of numbers in the table).

Remember the study provided data for 93 species, and whilst this is a lot of bees, there are about 25,000 known species in the world.  Any study can only reasonably provide us with a small snapshot. 

Bee   type	Genus	Brain size range (mg)
Large carpenter bees	Xylocopa	4.97 - 7.43
Bumble bees	Bombus	2.19 - 3.15
Leafcutter bees	Megachile	1.45 - 2.96
Wool carders	Anthidium	1.83 - 4.46
Honey bee	Apis mellifera	1.93
Plaster bees	Colletes	1.84 -1.96
Mason bees	Osmia	0.58 - 1.94
Mining bees	Andrena	0.25 - 1.97
End-banded furrow bees	Lassioglossum	0.23 - 0.82
Yellow-face bees	Hyleaus	0.26 - 0.29

The ranked brain size of 93 species of bee

Below are the sizes of brains of all 93 bee species included in the study.

Species	Subfamily	Brain Size (mg)
Xylocopa valga	Xylocopinae	7.43
Xylocopa violacea	Xylocopinae	5.876
Xylocopa virginica	Xylocopinae	5.438
Xylocopa cantabrita	Xylocopinae	4.968
Anthidium florentinum	Megachilinae	4.46
Amegilla quadrifasciata	Apinae	3.926
Anthophora plumipes	Apinae	3.676
Bombus vagans	Apinae	3.147
Bombus fervidus	Apinae	3.066
Megachile pugnata	Megachilinae	3
Megachile ligniseca	Megachilinae	2.963
Bombus terrestris	Apinae	2.823
Bombus impatiens	Apinae	2.821
Bombus pascuorum	Apinae	2.71
Megachile latimanus	Megachilinae	2.575
Rhodanthidium sticticum	Megachilinae	2.55
Megachile mendica	Megachilinae	2.452
Bombus hortorum	Apinae	2.334
Bombus jonellus	Apinae	2.301
Bombus hypnorum	Apinae	2.29
Anthophora quadrimaculata	Apinae	2.223
Bombus pratorum	Apinae	2.189
Bombus muscorum	Apinae	2.182
Anthidium manicatum	Megachilinae	2.053
Andrena nitida	Andreninae	1.974
Colletes compactus	Colletinae	1.962
Osmia cornuta	Megachilinae	1.94
Apis mellifera	Apinae	1.927
Colletes simulans	Colletinae	1.839
Megachile mucida	Megachilinae	1.839
Anthidium oblongatum	Megachilinae	1.83
Andrena carantonica	Andreninae	1.811
Andrena nigroaenea	Andreninae	1.713
Melissodes desponsus	Apinae	1.655
Andrena tibialis	Andreninae	1.648
Megachile relativa	Megachilinae	1.635
Andrena cineraria	Andreninae	1.633
Panurgus banksianus	Panurginae	1.63
Melissodes bimaculata	Apinae	1.614
Megachile rotundata	Megachilinae	1.6
Andrena gravida	Andreninae	1.594
Andrena fulva	Andreninae	1.591
Eucera elongatula	Apinae	1.59
Andrena carlini	Andreninae	1.558
Andrena morio	Andreninae	1.55
Dasypoda hirtipes	Dasypodainae	1.47
Megachile centuncularis	Megachilinae	1.449
Andrena flavipes	Andreninae	1.359
Andrena dunningi	Andreninae	1.348
Nomada succincta	Nomadinae	1.34
Osmia bicornis	Megachilinae	1.241
Andrena varians	Andreninae	1.17
Andrena haemorrhoa	Andreninae	1.166
Osmia leaiana	Megachilinae	1.103
Hoplitis papaveris	Megachilinae	1.1
Systropha planidens	Rophitinae	0.92
Agapostemon sericeus	Halictinae	0.855
Osmia caerulescens	Megachilinae	0.855
Andrena barbilabris	Andreninae	0.846
Halictus rubicundus	Halictinae	0.839
Andrena chrysosceles	Andreninae	0.831
Lasioglossum sexnotatum	Halictinae	0.818
Andrena nigriceps	Andreninae	0.814
Andrena nubecula	Andreninae	0.767
Andrena ovatula	Andreninae	0.746
Lasioglossum coriaceum	Halictinae	0.742
Augochlora pura	Halictinae	0.734
Andrena simplex	Andreninae	0.733
Andrena dorsata	Andreninae	0.718
Andrena bicolor	Andreninae	0.703
Andrena fucata	Andreninae	0.701
Lasioglossum zonulum	Halictinae	0.657
Lasioglossum calceatum	Halictinae	0.656
Flavipanurgus venustus	Panurginae	0.62
Halictus ligatus	Halictinae	0.617
Andrena miserabilis	Andreninae	0.6
Osmia submicans	Megachilinae	0.584
Andrena labiata	Andreninae	0.58
Ceratina calcarata	Xylocopinae	0.502
Panurgus calcaratus	Panurginae	0.487
Lasioglossum leucozonium	Halictinae	0.48
Lasioglossum cressonii	Halictinae	0.466
Heriades rubicola	Megachilinae	0.42
Halictus confusus	Halictinae	0.418
Stelis breviuscula	Megachilinae	0.382
Andrena subopaca	Andreninae	0.343
Lasioglossum fulvicorne	Halictinae	0.3
Lasioglossum punctatissimum	Halictinae	0.298
Lasioglossum imitatum	Halictinae	0.297
Hylaeus modestus	Hylaeinae	0.287
Hylaeus mesillae	Hylaeinae	0.26
Andrena semilaevis	Andreninae	0.254
Lasioglossum sexstrigatum	Halictinae	0.231

The ranked brains size of 93 species of bee, in proportion to body size by ITS

The rankings of bee brains change a little, when we consider the size of the brain in proportion to the body.

Species	Subfamily	Body Size ITS (mm)	Brain Size (mg)	Brain mg /mm
Xylocopa valga	Xylocopinae	7.024	7.43	1.058
Anthidium florentinum	Megachilinae	4.254	4.46	1.048
Amegilla quadrifasciata	Apinae	3.849	3.926	1.020
Xylocopa virginica	Xylocopinae	5.518	5.438	0.986
Xylocopa violacea	Xylocopinae	6.095	5.876	0.964
Xylocopa cantabrita	Xylocopinae	5.378	4.968	0.924
Anthophora plumipes	Apinae	4.08	3.676	0.901
Rhodanthidium sticticum	Megachilinae	3.272	2.55	0.779
Megachile ligniseca	Megachilinae	3.9	2.963	0.760
Megachile pugnata	Megachilinae	4.08	3	0.735
Bombus fervidus	Apinae	4.2	3.066	0.730
Megachile latimanus	Megachilinae	3.571	2.575	0.721
Anthidium manicatum	Megachilinae	2.874	2.053	0.714
Andrena nitida	Andreninae	2.808	1.974	0.703
Colletes compactus	Colletinae	2.814	1.962	0.697
Colletes simulans	Colletinae	2.66	1.839	0.691
Panurgus banksianus	Panurginae	2.379	1.63	0.685
Bombus hypnorum	Apinae	3.37	2.29	0.680
Bombus pascuorum	Apinae	3.995	2.71	0.678
Bombus impatiens	Apinae	4.184	2.821	0.674
Bombus vagans	Apinae	4.696	3.147	0.670
Andrena carantonica	Andreninae	2.775	1.811	0.653
Nomada succincta	Nomadinae	2.057	1.34	0.651
Bombus terrestris	Apinae	4.351	2.823	0.649
Bombus hortorum	Apinae	3.65	2.334	0.639
Apis mellifera	Apinae	3.018	1.927	0.639
Melissodes desponsus	Apinae	2.604	1.655	0.636
Bombus pratorum	Apinae	3.497	2.189	0.626
Megachile mendica	Megachilinae	4.01	2.452	0.611
Andrena gravida	Andreninae	2.635	1.594	0.605
Melissodes bimaculata	Apinae	2.672	1.614	0.604
Andrena cineraria	Andreninae	2.724	1.633	0.599
Anthidium oblongatum	Megachilinae	3.115	1.83	0.587
Megachile mucida	Megachilinae	3.164	1.839	0.581
Andrena fulva	Andreninae	2.76	1.591	0.576
Anthophora quadrimaculata	Apinae	3.86	2.223	0.576
Andrena carlini	Andreninae	2.712	1.558	0.574
Bombus jonellus	Apinae	4.018	2.301	0.573
Bombus muscorum	Apinae	3.812	2.182	0.572
Megachile rotundata	Megachilinae	2.86	1.6	0.559
Eucera elongatula	Apinae	2.846	1.59	0.559
Megachile relativa	Megachilinae	2.963	1.635	0.552
Osmia cornuta	Megachilinae	3.631	1.94	0.534
Andrena morio	Andreninae	3.04	1.55	0.510
Andrena tibialis	Andreninae	3.27	1.648	0.504
Dasypoda hirtipes	Dasypodainae	2.957	1.47	0.497
Hoplitis papaveris	Megachilinae	2.213	1.1	0.497
Andrena dunningi	Andreninae	2.784	1.348	0.484
Andrena nigroaenea	Andreninae	3.573	1.713	0.479
Andrena haemorrhoa	Andreninae	2.436	1.166	0.479
Andrena varians	Andreninae	2.52	1.17	0.464
Andrena flavipes	Andreninae	2.928	1.359	0.464
Andrena nubecula	Andreninae	1.709	0.767	0.449
Andrena chrysosceles	Andreninae	1.853	0.831	0.448
Megachile centuncularis	Megachilinae	3.402	1.449	0.426
Osmia leaiana	Megachilinae	2.766	1.103	0.399
Osmia bicornis	Megachilinae	3.172	1.241	0.391
Lasioglossum coriaceum	Halictinae	1.905	0.742	0.390
Systropha planidens	Rophitinae	2.405	0.92	0.383
Augochlora pura	Halictinae	1.954	0.734	0.376
Andrena barbilabris	Andreninae	2.292	0.846	0.369
Halictus rubicundus	Halictinae	2.314	0.839	0.363
Lasioglossum calceatum	Halictinae	1.892	0.656	0.347
Agapostemon sericeus	Halictinae	2.477	0.855	0.345
Panurgus calcaratus	Panurginae	1.416	0.487	0.344
Flavipanurgus venustus	Panurginae	1.874	0.62	0.331
Lasioglossum sexnotatum	Halictinae	2.56	0.818	0.320
Andrena bicolor	Andreninae	2.205	0.703	0.319
Andrena dorsata	Andreninae	2.262	0.718	0.317
Andrena nigriceps	Andreninae	2.62	0.814	0.311
Andrena miserabilis	Andreninae	1.957	0.6	0.307
Andrena simplex	Andreninae	2.391	0.733	0.307
Osmia caerulescens	Megachilinae	2.8	0.855	0.305
Lasioglossum zonulum	Halictinae	2.285	0.657	0.288
Halictus ligatus	Halictinae	2.189	0.617	0.282
Osmia submicans	Megachilinae	2.079	0.584	0.281
Andrena ovatula	Andreninae	2.693	0.746	0.277
Andrena fucata	Andreninae	2.66	0.701	0.264
Andrena labiata	Andreninae	2.233	0.58	0.260
Ceratina calcarata	Xylocopinae	1.953	0.502	0.257
Heriades rubicola	Megachilinae	1.642	0.42	0.256
Halictus confusus	Halictinae	1.681	0.418	0.249
Lasioglossum fulvicorne	Halictinae	1.26	0.3	0.238
Lasioglossum cressonii	Halictinae	2	0.466	0.233
Lasioglossum leucozonium	Halictinae	2.217	0.48	0.217
Lasioglossum imitatum	Halictinae	1.478	0.297	0.201
Lasioglossum punctatissimum	Halictinae	1.563	0.298	0.191
Stelis breviuscula	Megachilinae	2.02	0.382	0.189
Hylaeus modestus	Hylaeinae	1.53	0.287	0.188
Hylaeus mesillae	Hylaeinae	1.4	0.26	0.186
Andrena subopaca	Andreninae	1.847	0.343	0.186
Lasioglossum sexstrigatum	Halictinae	1.26	0.231	0.183
Andrena semilaevis	Andreninae	1.64	0.254	0.155

Note:  ITS = Intertegular span.  The distance between where the wings attach on the body. This measurement has been used as an estimate of bee body size and expected flight abilities (Cane 1987).

Resources

• Sayol, Ferran et al. (2020), Data from: Feeding specialisation and longer generation time are associated with relatively larger brains in bees.
• Engle C., Baum K., Can You Bee-lieve it? The Intertegular Span of Bees, Howard Hughes Medical Institute.
• Mares S, Ash L, Gronenberg W. Brain allometry in bumblebee and honey bee workers. Brain Behav Evol. 2005;66(1):50-61. doi: 10.1159/000085047. Epub 2005 Apr 8. PMID: 15821348.
  

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