"The men of experiment are like the ant; they only collect and use. But the bee... gathers its materials from the flowers of the garden and of the field, but transforms and digests it by a power of its own."
Leonardo da Vinci
English summers always come hand in hand with bees. Honeybees and bumblebees, I'm pleased to see either, though I'm usually the only one. It usually goes the same way; a group of us'll be sitting out in a beer garden, enjoying the sun and the chitchat, when a small scream and a stampede will indicate the arrival of something with wings and black and yellow-stripped abdomen. My cry of "It's okay, it's furry!" is usually ignored, and I'm left alone with my new friend until it tires of me. You see: if it's furry, it's a bee; if it's not, it's a wasp.
Yellowjackets can be pretty nasty in Blighty. Some say they'll sting you as soon as look as you, but in truth it's usually only if you provoke them. People still run though; I'd like to point out that they're still being big sissies.
There seem to be a lot less bees about than there were when I was a small 'un. Bumblebee populations have been hit hard by a decrease in size of their natural habitat, and honeybee populations are currently being decimated by the Varroa mite. Nowadays, the arrival of something with wings and black and yellow-stripped abdomen will have me upending an empty pint glass over the offender to ensure the return of my comrades; it's usually a wasp.
You just don't seem to see bees as much anymore.
What are bees?
Well, in the nature of things (as mapped out by man) bees, along with wasps, make up the super family Apoidea (formerly Sphecoidea)
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Suborder: Apocrita
Superfamily: Apoidea
So, a stating of the obvious, because sometimes the obvious isn't all that obvious. A bee is a winged, flying insect. They can be solitary, or may live in a colony with many thousands of other individuals, and the current ballpark estimate is that there are more than 16,000 different species. They are very similar to wasps, and the two are often confused. The main difference, as I've said, is that bees are hairier and usually more robustly built than wasps. Bees rely on pollen collected from flowers as the source of protein for their growing larvae; the only exception to this is one small family of bees that rely on carrion, but more of that later. Bees are plant feeders; in comparison, wasps will catch small insects to feed to their offspring, and while they will drink nectar, they do not collect pollen.
Development of the bee
All insects go through four growth stages: egg; larval; pupal; and adult.
Egg: The eggs of bees are quite interesting: the fertilised eggs will develop into females; the unfertilised eggs will develop into males. After she has mated, the female or queen stores the sperm (a lifetimes' supply, would you believe) in her spermatheca. She can then control the sex of each egg by choosing whether or not she releases sperm as she lays. The number of eggs laid will vary between species: as few as eight for solitary bees; more than a million for a queen of a highly eusocial hive. The eggs themselves are usually elongated, curved, whitish, and with a soft membranous 'shell' called a chorion, and are laid onto food that is provided for larval consumption.
Larvae: The larvae of bees are soft, whitish, legless grubs that rest atop a food mass of pollen (or similar) that they gradually munch their way through, growing rapidly. They will eat until all the food is gone, and will usually shed their skin about four times in the process. For many species of bee, the larvae will at this stage spin itself a cocoon of silk fibres.
Pupation: The pupae of bees are delicate and have to develop into adults rapidly in order to survive, with the exoskeletons needing to harden and wings yet to develop.
Adult: The adult bee will finally emerge from the nest or hive, and will fly off to feed and mate, as adults are wont to do. It's hard to get into the specifics of what happens next, as different bee species will do different things: some have a relatively short lifespan of only a few weeks; others can hibernate through the winter to build their own nest in the next spring.
Anatomy of the bee
The body of the bee is made up of three main segments: the head (prosoma), thorax (mesosoma) and gaster (metasoma, or abdomen).
The major structures of note in the head of the bee are:
- proboscides (singular: proboscis), an elongated structure used to gather the nectar from flowers, that folds underneath the head when not in use
- mandibles, used to cut through vegetation, manipulate objects, or attack and hold any other invading insects
- antennae, are a pair of sensory organs extending from the forehead of the bee that they probably use to detect odour particles; males usually have 13 segments (antenomeres), while females usually have 12, but this varies from species to species
- compound eyes, while far too complicated to explain in a sentence, allow the bee to detect light and movement
The major structures of note in the thorax of the bee are:
- two pairs of wings, the forewing being larger than the hindwing
- three pairs of legs, as for all insects
The major structures of note in the gaster (Latin for stomach, from the Greek, 'gastér', belly) are:
Bee Societies
Female bees can either be solitary, or live in colonies. A solitary bee, as the term implies, will build and guard her own nest, and alone provides food for her offspring. She usually dies or leaves before her offspring mature. Sub-social describes a solitary bee that remains to care for her offspring rather than merely storing food for them before leaving.
A colony consists of two or more adult females living in a single nest. Often, people think of a bee colony as being highly eusocial, perennial, and with a large number of unmated female worker bees who will build, forage for food, and guard the nest; and a mated queen bee who lays the eggs. However, only two tribes live like this: the Apini (honey) and the Meliponini (stingless) bees from the Apidae family, Apinae subfamily.
Most bumblebees, sweat bees, and carpenter bees live in small colonies where a single female will lay eggs, and then work with the daughters that hatch to expand the nest further: primitive eusocial colonies. 'Eusocial' as a descriptor means that there is a division of labour amongst the colony members. Not all bees that live in colonies are eusocial: the term 'semi-social' describes small colonies where there is still a division of labour between sisters of the same generation after the queen has died; 'communal' describes two or more females using the same nest, but with each looking after her own eggs. Often there will be an 'aggregation' of individual nests, probably because of the suitability of that patch of soil for burrowing rather than any desire to be close to other members of the same species.
Types of bee
Bees are divided into various families based upon shared anatomical traits, and these families are broken down into subfamilies, which are in turn often broken down into tribes. There are literally thousands upon thousands of different bee species (and counting) in the world. Descriptions of the various bee families would be best served by a writeup in their own node, but here's a skeletal outline...
Andrenidae
Consists of four subfamilies: Alocandreninae, Andreninae, Panurginae, and Oxaeinae. Andrenidae can be found across all the continents except for Australia (and Antarctica, but that's true of all bees), and are only rarely found in the tropical Asian and sub-Saharan regions. They nest in soil and dig out their own burrows. They do not spin cocoons.
Apidae
Consists of three subfamilies: Xylocopinae, Nomadinae, Apinae; however, these three subfamilies contain large numbers of tribes, making Apidae the largest family of all the bee families. The Apinae subfamily contains the eusocial honeybees, bumblebees and stingless bees; the Xylocopinae subfamily contains the semi-social carpenter bees. The Nomadinae subfamily are a species that practice kleptoparasitism; they lay their eggs on another species' pollen masses. These bees are called 'cuckoo bees'. Apidae are found worldwide, and are an extremely diverse family. They also contain the single species that feed on carrion – Trigona corvina ('vulture bees'), a member of the Apinae subfamily and Meliponini tribe, that can be found in Central America.
Colletidae
Consists of five subfamilies: Colletinae, Diphaglogginae, Xeromelissinae, Hyaeinae, and Euryglossinae. They are often referred to as 'plasterer bees'. All species of colletidae are solitary, though they might nest in aggregations. They usually burrow into soil or live in pre-existing holes in wood or volcanic rock, but one species burrows into rotting wood, and another resides within pithy stems. They are found world-wide, but are most abundant in the temperate areas of Australia and South America.
Halictidae
Consists of four subfamilies: Ropitinae, Nomiinae, Nomioidinae, and Halictinae. They are often referred to as 'sweat bees' as they are attracted to perspiration, and are usually a bright green or bright red colour. They are found in temperate climates across the world, and in fact are the most common type of bee found in North America. They burrow in soil, or, rarely, in rotting wood. Many of the Halictinae bee species are eusocial.
Megachilidae
Consists of two subfamilies: Fideliinae, and Megachilinae. They are mostly solitary and are found worldwide. The Megachilinae subfamily are more commonly called 'mason bees' or 'leafcutter bees', because unlike some bees which line their burrows with a self-produced secretion of some sort, these bees use foreign material to line and build their nests. A few collect animal hairs or plant fibres, and these are called 'carder bees'. This family also contains some species of cuckoo bees.
Melittidae
Consists of three subfamilies: Dasypodainae, Meganomiinae, Melittinae. This is a small family, with only 110 species discovered so far. They burrow into the soil. They are mostly found in the temperate regions of the Northern Hemisphere and Africa, with the greatest number being found in dry, warm areas.
Stenotritidae
This, to buck a trend, is the only family to contain no subfamilies. There are only 21 species discovered so far, and they all live in Australia. They dig burrows, and do not spin cocoons.
Bees and flowers
Bees are super-important, but so few people realise this. The main pollinators of flowers in this world are bees and the wind. Bees are therefore responsible, nay, essential for the sexual reproduction of the natural vegetation of the world, as well as agricultural crops. Most of the trees in tropical forests are bee-pollinated. Pollen is the principle source of protein for bees, and so is eaten by adults, and carried to the nests by females. Pollen may stick to the legs of the bee because they are spiny, sticky, or because they carry an electrostatic charge, but the result is the same; as the bee moves from flower to flower, pollen from the anther of one plant is deposited on the stigma of another of the same species, allowing cross-fertilisation. The nectar produced by the plant is the bees' principle source of carbohydrate, and so is another incentive to pick up pollen and transfer pollen from flower to flower. Many bees are flower specific; they only visit the single plant species, and are thus vital for that plants' continued survival. Even generalist bees show a preference for particular flowers.
Wild bee populations are currently under considerable threat from human activity: either from destruction of the specific plant life upon which they rely on for food; destruction of their habitats by agriculture, the building of roadways and housing, etc.; overuse of insecticides... They live in such a symbiotic relationship with the plants that they feed off, that if one dies, the other will too. Bees are probably the only insects that, as a generalisation amongst humans, don't provoke revulsion. Fear, yes. Revulsion, no. So the next time a conservationist kicks up a fuss in your area about the destruction of local wildlife, maybe lend them an ear for a while.