British Pollinators

British Pollinators

The AgriLand project is concerned principally with bees, wasps and hoverflies. These groups are all important pollinators for a number of crop and wildflower plants. It's not just honeybees that provide this service!

While honeybees can be important pollinators for a large number of flowering plants due in part to their sheer number and the fact that their colonies can be moved around to large patches of flowers, other insects can actually be more effective at pollinating certain plants. For example, bumble bees are particularly adept at "tripping" the complex flowers of legumes such as clovers and vetches.

There are about 250 species of Bumblebee worldwide and 24 species in Britain, although only 8 of these are common throughout the country. Most people know the most common bumblebees when they see them, but generally bumblebees are larger than honeybees and are always covered in dense hairs, charateristics that make them particualrly good for pollination, because it creates a large surface area for pollen to become attached (source: Bumblebee Conservation Trust).

Apart from bumblebees, there are also about 225 species of solitary bee in the UK. The term "solitary bee" refers to their habit of nesting alone, unlike bumblebees and honeybees that nest in colonies. There are a number of different types of solitary bee, including mining bees (Andrena species) that "mine" their nests in the ground, leaf cutter bees (Megachile species) that cut sections of leaf to build nests dead plant stems for example, and mason bees (Osmia species) that nest in crumbling bricks and walls. These species are also excellent pollinators (source: Royal Entomoligcal Society).

Hoverflies are so called because they display a hovering flight patten, and there are about 270 species in the UK with a range of shapes, sizes and habitat types. Such diversity may make them good specialist pollinators, although a number of generalist feeding hoverflies may also be important pollinators to a range of flower species. Many hoverfly species also have larvae that feed on insect crop pests, so they are useful insects to attract to gardens and farms (source: Buglife).

Like honeybees and bumblebees, some wasps live in colonies and the workers spend much of their time foraging for nectar and pollen, hence their potential as useful pollinators. However the majority of the 350 species of wasp in the UK are solitary, and while their importance as pollinators is uncertain, they are likely to influence the effectiveness of other pollinators (source: Buglife).

Here are some tips on how to tell these groups apart:

Hoverflies:

- They have one pair of wings which has a "floating vein" (spurious vein) and they have two outer cross veins both near the wing margin. Figure coming soon!

- They have no bristles on the top (dorsal) of their thorax. They may have a few on the margins of the thorax and they may have fine hair all over. This character is easy to see without a microscope so is usually the first characteristic to check if it’s a hoverfly or not.

Bees vs. Aculeate Wasps:

- Both have a narrow waist between the thorax and abdomen

- Bees are typically hairy but some may have short fine hair but they will have some hairs especially by the tegula (see this website) and usually some on the legs. The hair is kind of "feathery" and branched. Wasps usually have little hair and any hairs present are not branched and feathery.

- Some bees’ hind tibia and tarsus are often enlarged (especially in females). Wasps legs are typically ‘uniform’.

- Bee’s pronotum (the first segment of the thorax) from above, does not reach back to the tegulae (where the wings meet the thorax) and therefore the pronotum is usually quiet short and straight (if the pronotum is not visible due to dense hair then this it is a bee). However digger wasps also have this feature but their hair will be unbranched. Other aculeate wasps’ pronotum reach back to the tegulae.

Other Hymenoptera:

Symphata (sawflies): They don't have the typical narrow waist that bees and wasps have. Also, they have cenchri (singular cenchrus) which are used to keep the wings back when not in use – bees don't have these cenchri. They are like two ‘blisters’ on their thorax, see this picture, and are very distinctive.

Parasitica Wasps: They have less than six cells in their forewings - Aculeates have more than six. They also have long antennae with typically more than 16 segments –Aculeates have between 10 and 13 (usually 12 for females and 13 for males).

Useful Resources:

BWARS gives an excellent introduction to people just learning about British pollinators (http://www.bwars.com/index.php?q=content/beginners-bees-wasps-and-ants). They also give fantastic information to the more experience pollination biologist (http://www.bwars.com/index.php?q=content/key-works-identifying-bees-wasps-and-ants).

The bumblebee conservation trust gives excellent ID tips for common bumblebees (http://bumblebeeconservation.org/images/uploads/Resources/BBCT_Bumblebee_ID_sheet_(big_8).pdf), cuckoo bees (http://bumblebeeconservation.org/about-bees/identification/less-common/), scarce bees (http://bumblebeeconservation.org/about-bees/identification/scarce/) and rare bees (http://bumblebeeconservation.org/about-bees/identification/very-rare/).

A flicker site for social wasps: http://www.flickr.com/photos/63075200@N07/collections/72157629294465012/

This website is a fantastic glossary with most terms and attached diagrams and pictures for better visualisation of the anatomy actually being described. http://www.hymatol.org

A fantastic field book for bumble bees: Edwards, M. & Jenner, M. (2009). Field Guide to the Bumblebees of Great Britain & Ireland. Ocelli Ltd. This is an excellent guide that is easy to use and to carry in the field. It contains a quick colour pattern key to UK species, plus colour photos of all the UK species.

Useful for all identifying the difference between Aculeates and Parasitic Wasps, and the Genera of the British Aculeates: Wilmer, P. (1985). Bees, Ants and Wasps - A Key to the Genera of the British Aculeates. Field Studies Council. An Aidgap tested key.

 

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