A Name of Two Halves

Hi All!  I have been working this week on the 2nd edition of the Bees of Walsall, which will be out in October/November.  There are loads more sites, many more species, and several new chapters.  I thought I’d give you an idea of what I’m working on.  Here’s the new chapter on scientific nomenclature – so if the scientific names of species is all Greek to you, you might enjoy this:

“You’ll see as you go through this book (and you may have noticed on websites and in field guides), a common name for a bee (i.e. Tree Bumble Bee) followed by two latin or greek words in italics (i.e. Bombus hypnorum). This is called a binomial. It is also sometimes called a ‘latin name’ (although it is not always latin – often greek or a derivation of the name of the naturalist who discovered the species) or a ‘scientific name’ and it is part of the way in which scientists classify organisms. In printed text the binomial will always be in italics; in hand written text it is usually underlined (this is just taxonomic etiquette, but a useful habit to get into).b hypnorum

The first of these two words is the Genus, which is the group of animals to which the organism belongs. If you see ‘Bombus‘ this means you are looking at a bumble bee. The second word refers to the species. A species is (generally – there are some exceptions) an animal that can only produce viable offspring with another of its kind. So a horse and a donkey are different species because, although they can reproduce, their offspring (mules) are infertile; but they ARE both in the same genus.

Sometimes you will see three names rather than two – this means that it is referring to a subspecies (i.e. Wolves are Canis lupus; domestic dogs are Canis lupus familiaris.

You might wonder why we bother, and why we don’t just use common names. There are two main reasons for this – firstly, the binomial lets us know instantly how an animal relates to other animals without having to look it up, and secondly, it transcends international changes in common names. One example of this is the group of birds called ‘buzzards’. In the United States these are called ‘hawks’, which can be confusing as here we have ‘sparrowhawks’ which are not in the same genus. Calling this group of birds by their genus: ‘Buteo‘ lets us know that, for example, the American ‘Red Tailed Hawk’ is more closely related to our ‘European Buzzard’ than to the ‘Sparrowhawk’, even thought the common names would imply the opposite.

Andrena fulva
Andrena fulva

As you do more reading you will see binomials shortened: ‘B. hortorum‘ instead of ‘Bombus hortorum‘. This is almost always done AFTER the full genus has been mentioned, and it is a generally accepted shorthand in natural history texts. However it wouldn’t be right to talk about Andrena fulva (Tawny Mining Bee) and then shorten Apis mellifera (Honey Bee) to A. mellifera as it can be confusing.

In addition, you may see the genus followed by ‘sp.‘ or the plural ‘spp.‘ – this stands for ‘species’. The ‘sp.’ is singular, and is used, for example, when referring to an unidentified species: “Im not sure what this bee is; probably an Andrena sp.” Alternatively, if you see the plural ‘spp.‘ after the genus, it means that it is referring to more than one species in this genus: “Megachile spp. carry their pollen on their abdomen while Andrena spp. carry pollen on their legs.”

b hortorum
Bombus hortorum

The other thing you may encounter is that entomologists have ‘pet names’ for species. For example, you might hear someone say ‘I found a HUGE hortorum nest today!’. They are referring to Bombus hortorum (The Garden Bumble Bee), but as there are no other common species called ‘hortorum‘, this is a generally accepted way to shorten it.  Having said that, you WOULDNT say ‘I saw a beautify humilis today!” because there is both a Bombus humilis and an Andrena humilis. (I know it’s confusing at first, but I promise you’ll get the hang of it – a good way to start is to try to learn one group of bees at a time, and you’ll remember the binomials more easily.)

One last thing on the subject of nomenclature – the names change! All the time! While this causes a good deal of eye rolling in the field, and can be confusing, it is a necessary part of the process. As we learn more about species and about their relationships with other species, scientists often correct the binomials to keep up with modern taxonomic knowledge. A huge example of this in the Bee world is the change in 1994 of the genus name ‘Psithryus‘. This used to be the name for the genus of Cuckoo Bumble Bees – there are 29 species in the world (six species in the UK). But they are now regarded as being in the genus ‘Bombus‘ along with other bumblebees, with ‘Psithryus‘ being considered a subgenus (a subset) of ‘Bombus‘. The ‘Psithryus’ part is not usually written in the binomial, but if it is, it is written like this: ‘Bombus (Psithryus) rupestris‘.

Osmia bicornis
Osmia bicornis

Sometimes this only happens to a specific species – the Red Mason Bee (Osmia bicornis – so named for the two horns on the face of the female) used to be called ‘Osmia rufa‘. This change is so recent that many entomologists still talk about ‘Osmia rufa‘ in the field. This happens sometimes due to the discovery or acknowledgment of an original type specimen or description:

Bombus rupestris
Bombus rupestris

For example, the dinosaur Brontosaurus doesn’t exist! The species was described in 1879 by O.C. Marsh and named ‘Brontosaurus‘ (its actually quite a hilarious story and worth Googling). It was later discovered that the specimen was the same species as one he had described and named two years earlier: Apatoaurus. In science, the earliest description of a specimen is always considered the genuine one, so the Dinosaur books had to be re-written!

You may occasionally see a name and date written after a species – this refers to the person who first described and named the species (Called the ‘authority’), and the date in which they did so. So you could see the Red Tailed Cuckoo bee written as either ‘Bombus rupestris‘, ‘Bombus (Psithryus) rupestris‘, ‘Bombus rupestris (Fabricius, 1793)’ or ‘Bombus (Psithryus) rupestris (Fabricius, 1793)’ – but they all refer to exactly the same species.

Another post-script to binomials is the ‘sensu scripto / sensu lato’ addendum. These two phrases are sometimes appended to the binomial of an organism to indicate how looseley the identification is intended. ‘Sensu scripto’ (also written ‘sens. scr.’ or ‘s.s.’) means ‘strictly speaking’ and ‘sensu lato’ (also written ‘sens. lat.’ or ‘s.l.’) means ‘looseley speaking’.

Bombus lucorum sens. lat.
Bombus lucorum sens. lat.

For example the White Tailed Bumble Bee, Bombus lucorum is actually part of a group of species which cannot be readily separated (Bombus lucorum, Bombus cryptarum and Bombus magnus). As a result, it is often recorded as ‘Bombus lucorum sensu lato’, which indicates that you are acknowledging that it is part of this group but you cannot tell which of the group it is. Another way of thinking about ‘sensu lato’ is that it means “Including all its related and sub-species which are usually considered as separate”.

A great deal of emphasis is placed on accuracy in biological recording. One of the main principles is not recording anything unless you are SURE which species you have identified. ‘Sensu lato’ allows us to record the White Tailed Bumble Bee without dissecting it!

I hope this helps you wade through the muddle of scientific nomenclature. Taxonomy and cladistics is a dynamic field of study, and we must all adjust in the name of greater accuracy and scientific knowledge.”

14 Replies to “A Name of Two Halves”

  1. You have explained that so clearly. The examples are very pertinent and beautifully illustrated. I think it will de-mystify the naming system for a lot of people. I must confess I had never noticed the “sensu lato” and would not have known what it meant. Amelia

  2. Thanks, Amelia! Whenever I teach bee workshops or lead a walk, people always seem so intimidated by scientific names, so I wanted a chapter at the beginning of the new book to talk about it a bit. 🙂

  3. Thanks for this; really well explained!
    What camera do you use? I am looking for a new one, but not too heavy to hold and carry around.

    1. Hi Louise! Hope you are well and ready for bee season! These pics were taken with an Olympus EPL1, which is a micro 4/3 camera so nice and light. Loved it so much I stuck with Olympus for my upgrade which is an Olympus OMD. 🙂

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