So, my recent post on
short-haired bumblebees
got me a-wonderin' about bees. There's honey bees, bumblebees, carder
bees, cuckoo bees, carpenter bees, sweat bees, stingless bees... and
they're just the ones that spring immediately to my mind. But what's the
difference between the bees and why don't we eat bumblebee honey?
WHAT THE F*** IS HONEY ABOUT
|
Honeycomb, George Shuklin |
Honey is a food source used by some social bees to feed their young.
It's essentially nectar from flowers that foraging worker bees have
sucked up into a special nectar stomach. When a foraging honeybee
returns to the hive it regurgitates the nectar into the mouth of a hive
bee. The hive bee then adds various enzymes and such that break down the
complex sugars into more simple fructose and glucose. Once this is
done, the honey is deposited into a wax honeycomb, the hive bees fan the
comb to help water evaporate increasing the sugar concentration -- once
the honey is a supersaturated solution that by rights shouldn't be
liquid, the bees seal of the honey, which is then ready to use as a food
source for the hive in winter. The primary food source of most bees is
pollen, some bees other than honeybees do make honey, but only in small
amounts and never to quite the same magical effect: bumblebee honey is
often said to be quite watery, and no more than a 100 g (usually a lot
less) will be in the colony at any one time.
HONEY IS THE ONLY FOOD THAT DOESN'T GO OFF
If anyone ever asks you in a pub quiz what the only food is that never
goes off, answer "honey" -- it's the answer they want. However, this
isn't really true. So, OK, honey is pretty sterile and almost no
bacteria will grow in it. When it changes from liquid to solid in your
cupboard, that's just a process of crystalisation and it's still
perfectly edible. So yeah, maybe honey won't go off as long as it
doesn't get wet. But what about salt, and sugar, and canned goods? They
don't go off? I've got a bag of flour in my cupboard with a best before
date of 2005, it's fine! How many times have you read a news story about
a can of Spam found in an old bomb shelter that still tasted just as
good as the day it was canned during the Blitz? I mean, I don't know
what the strict definition of "foodstuff" is, but I'm about as likely to
eat a bowl of sugar as I am a bowl of honey -- and I'm as likely to add
salt to my porridge as I am honey (I'm no Goldilocks).
BEES' DISTANT COUSINS
Bees are part of the large group of
insects, the hymenoptera, the etymology of which I once discussed
here, which also include sawflies, wasps, and
ants.
With over 130 000 species, hymenoptera are one of the largest groups of
insects; we know quite a lot about some hymenoptera because the trait of
sociality, which is by no means universal to the group, but expressed
by many of the best known members (some bees and wasps and all
ants).
Sociality in this sense is not just hanging out together, lots of
animals do that, but rather hanging out in groups in which different
individuals have different roles within the group (for example, but not
limited to, workers, reproductive individuals, guards, and so on). This
form of sociality, called eusociality by biologists, is very rare in the
animal kingdom,
naked mole rats provide another example.
BEEING
There
are nine families (groups based on shared physical and genetic
characteristics) of bees comprising 20 000 known species found on all
continents except Antarctica. But we are perhaps most interested in bees
because of just one species, the honey bee,
Apis mellifera. Among the 20 000 bee species, honey bees and bumblebees are quite closely related, relatively.
BUMBLEBEES
Bumblebees, any of 250 species in the genus
Bombus, belong to the
same family as honeybees. They are essentially large, hairy, social
bees. Unlike honeybees, bumblebees live in small colonies of at most a
hundred or so individuals that typically die off after just one breeding
season. A queen will start a colony in spring,
or earlier,
produce workers throughout the summer. Towards the end of the summer,
the colony will start to produce breeding bees -- queens and drones.
These bees fly off, look for mates from other colonies, and the mated
queens then hibernate, emerging in spring to start a new colony.
WHEN IS A BEE A CUCKOO?
|
Cuckoo bee |
NEVER! However, there are quite a few species of bees that have given up
collecting pollen and nectar to feed their own young, and instead lay
their eggs in the colonies of other bees, just like the European cuckoo
does with other birds. Most cuckoo bees belong to the group Nomadinae,
and these generally look a bit waspish, parasitise solitary bee species,
and nip in to a nest, lay their egg, and leave. In the genus
Bombus, cuckoo bees in the subgenus
Psithyrus resemble
closely the social bumblebees they parasitise; the cuckoo queens invade
the bumblebee colony, kill the queen and take up residence, getting the
workers of that colony to raise her own brood.
ETYMOLOGBEE
Just 153 years ago in the Origin of Species, Darwin wrote of humblebees
rather than bumblebees, and for centuries before, although both terms
were in use, humblebee was more prevalent. For no apparent reason,
however, since the end of World War II the term humblebee has fallen
into almost complete disuse. The "humble" had nothing to do with pie or
low rank, but instead was related to the hum the bees make as they fly.
The Latin name for the genus of bumblebees is
Bombus, so one
might think that the newly adopted preference for the "b" spelling arose
that way somehow given the similarity between "humblebee" and
"bumblebee". This is actually all much of a muchness: the Latin "bombus"
has its origins in the Greek "bombos" meaning "hum".
STINGLESS, CARPENTER, MASON, SWEAT
No, I'm not counting cherry stones. There's basically crap loads of bees
-- like honeybees, bumblebees, cuckoo bees, many of their names
describe their habits. Sweat bees are attracted to human sweat, as such
you'd think I'd be more familiar with them than I am. Most stingless
bees are social relatives of honeybees that, you guessed it, can't sting
because their stingers are greatly reduced; although several other
groups of bees have lost their stings, and are also stingless bees but
not known as such. Carpenter bees nest in holes in wood, bamboo, or
structural timber. Mason bees make compartments of mud or clay in their
nests. Orchid bees are bees from central and south America that gather
fragrances from orchids. There are so many bees that some of them don't
even have common names: the 25 species in the smallest family of bees,
the Stenotritidae, are known only by their latin binomials.
|
Orchid bee |
TWO BEES OR NOT TWO BEES
Although we often think of bees as social animals, the vast majority of
species aren't. The same is true of wasps and sawflies their
hymenopteran cousins. Rather than being common to all hymenoptera,
sociality has evolved numerous occasions within the group. The reason
bees, ants, and wasps are prone to sociality is probably to do with the
haplodiploid method of sex determination, which means that males arise
from unfertilised (haploid; one set of chromosomes) eggs, but females
arise from fertilised (diploid; two sets) eggs -- this means that
sisters are often more closely related to each other than to their
mothers or fathers, which means that cooperation between sisters will
lead to evolutionary success.
BEE GEEKERY
Actually, sometimes diploid bees will be males, but that's because they
share identical copies of the genes that determine sex on both the
relevant chromosomes (normally the copies of these genes on two
different chromosomes in a pair would differ).
The likelihood of
a queen producing a diploid drone increases if the male she mates with
is a close relative. Diploid drones are less fertile than haploid
drones, so actually detrimental to a colony -- workers typically sniff
out diploid drones and kill the larvae before they develop too far, thus
saving the hive the energy of raising them.
EPBEELOGUE
This, er, brief foray into the world of bees reflects some things I
thought interesting about bees, some things I'd wondered about, and then
some interesting things I found out while researching the things I had
pondered. There's about a million and one things known about bees that I
have not even scraped the surface of, and even more that people don't
know about bees. But don't you worry, I am sure to return to the topic
in future AOTWs. One might say "I'll bee back".