Shrill carder bee (Bombus sylvarum)

Description

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Shrill carder bee fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Shrill carder bee description

The shrill carder bee is one of the smaller members of the bumblebee family. It has a distinctive combination of markings, being predominantly grey-green, with a single black band across the thorax, and two dark bands on the abdomen. The tip of the abdomen is pale orange. The queens fly very quickly and produce an audible high-pitched buzz. Although workers and males fly equally fast, they appear to be far less noisy. The combination of rapid flight and distinctive colouration make this species fairly easy to identify.

Size

Worker length: 10 - 15 mm

Queen length: 16 - 18 mm

Shrill carder bee biology

Queens emerge from hibernation in mid to late April. Nests are constructed from grass stems and other dead vegetation, either on the surface or slightly below ground. The old nests of mice or voles sometimes form the foundation, and the colony may only number fewer than 100 workers. However, nests can survive until late September.

Shrill carder bee range

The shrill carder bee is found throughout Europe and is declining throughout its range. In the UK, it was considered a common species in the 19th century and the early part of the 20th century. However, records since 1970 indicate that it has declined drastically in the UK, and is now only known from seven populations. These are in Kent, Essex, Wiltshire, Somerset and South Wales.

Shrill carder bee habitat

This bee is an insect of extensive areas of herb-rich grassland of the sort that used to be widespread in Britain. Today, populations are restricted to large military ranges, unimproved pasture across the Somerset Levels, and brownfield sites along the Thames corridor.

Formerly common and widespread meadow and hedgerow plants with long corollas, such as vetches, clovers, dead-nettles and the red bartsia, are essential sources of pollen and nectar. It has been estimated that, to remain viable, individual bee populations require an area of suitable habitat of at least 10 square kilometres. Nectar and pollen supplies need to be available throughout the bee’s flight period of April to September.

Shrill carder bee status

Classified as Endangered in the UK.

Shrill carder bee threats

The loss of unimproved flower-rich grasslands, unploughed and unsprayed field headlands and hedge banks, as a result of agricultural improvement and intensification, has been the major cause for the decline of this and many other species of bumblebee. Heavy and continued grazing of flower-rich sites also poses a threat, and the existing populations along the Thames corridor are presently being threatened by proposed development.

Shrill carder bee conservation

The shrill carder bee is listed in the UK Biodiversity Action Plan (UKBAP) and is included on English Nature's Species Recovery Programme. It is one of several species of bee that is threatened in Britain, and in 1998, the UKBAP Bumblebee Working Group was set up to discover more about the status of many endangered bees. The group consists of seven conservation bodies, including three of the UK statutory bodies; English Nature, Countryside Council for Wales and Scottish Natural Heritage.

Survey work has begun to establish the true numbers and ranges of several species of bumblebee, and the working group has published a series of recommendations for restoring the bee's populations. These include encouraging the practice of leaving field margins undisturbed and free from herbicide and pesticide treatment, the re-creation of herb-rich meadows, and the modification of grazing regimes on existing grassland. They also suggest modifying the grazing patterns on existing grassland, and erecting artificial nest boxes to encourage queen bees to start a colony.

The UK Biodiversity Action Plan for this species is available at UK BAP.

Authentication

Information supplied and authenticated by Bryan Pinchen (independent ecologist).

Glossary

Abdomen

In arthropods (crustaceans, insects and arachnids) the abdomen is the hind region of the body, which is usually segmented to a degree. In crustacea (e.g. crabs) the limbs attach to the abdomen; in insects the limbs are attached to the thorax (the part of the body nearest to the head) and not the abdomen. In vertebrates the abdomen is the part of the body that contains the internal organs (except the heart and lungs).

Corollas

The petals of a flower considered as a group or unit and usually of a colour other than green; often arranged in a whorl.

Hibernation

A winter survival strategy characteristic of some mammals in which an animal's metabolic rate slows down and a state of deep sleep is attained. Whilst hibernating, animals survive on stored reserves of fat that they have accumulated in summer. In insects, the correct term for hibernation is 'diapause', a temporary pause in development and growth. Any stage of the lifecycle (eggs, larvae, pupae or adults) may enter diapause, which is typically associated with winter.

Thorax

Part of the body located near the head in animals. In insects, the three segments between the head and the abdomen, each of which has a pair of legs.

References