Countryside Caretakers

My grandparents used to tell me that bees are the caretakers of the countryside, as that they ensure the continued blooming of the flowering plants year-on-year, and the survival of the trees and shrubs. It is very true that bees are vital for the propagation of plants each year, as they constitute a large proportion of the pollinating insects.

Class - Insecta

Order - Hymenoptera

Family - Apidae

Genus - Bombus

A Bumble Bee - taken 26/03/17

There are approx. 275 species of Bumblebee currently described in the world today, and whilst they are mainly found in the higher latitudes of the northern hemisphere, the genus may also be found in parts of southern America, and they have been introduced to Tasmania and New Zealand. There are 25 species of bumblebee in the UK today. Bumblebees typically prefer temperate climates, however, B. polaris is one of the few Bombus species which may be found on Ellesmere Island in the Arctic; this is the northernmost habitat of any eusocial insect. Interestingly, B. polaris can survive in such cold temperatures as a result of being able to regulate their body temperatures by means of evolutionary adaptation producing a "shivering" mechanism, and via solar radiation. They are heterothermic, as they can regulate their body temperature through both cold and warm climatic episodes.

Bumblebees are predominantly social insects which live in large colonies with one queen, although there have been cases where small colonies have been recorded, with as few as 50 individual bees. Bumblebees typically nest underground, or under old plant-pots or garden ornaments, as they prefer nest-sites that are shaded to avoid overheating. Bombus nests are only built to last for one single year, and a new nest-site will be chosen each year. Unlike honeybees, bumblebees don't communicate to others in their nest the location of flowers through use of a "waggle dance". Instead, it has been observed that returning bees to a nest will almost rampage around the nest before leaving to forage once again, and it is believed the bees are communicating through use of sounds produced by the movement of the bee's wings.

In the early spring, around mid-March, female Bumblebees which have hibernated over winter, will awake from diapause and find a new place to build a nest. Upon finding the perfect nest-spot, the female (queen) bumblebee, will start producing wax cells in which she will lay her eggs (already fertilised). Fertilised eggs will become females, and unfertilised eggs produce haploid males.

Bumblebees feed using a specialised "tongue", called the proboscis. The proboscis is a long tongue-like structure with tiny hairs, and bees feed by using it to lap up nectar from flowers. When in-flight, the proboscis is kept underneath the head. Bombus bees produce a wax that is used in the erection of "honeypots", as a lining for empty cocoons for use as storage containers, and also to cover the exterior of nests. The wax is produced by glands on the abdomen of queen bees after she starts a nest of her own, and by young worker bees.

Bumblebees have brightly coloured yellow stripes running across their abdomens, which act as aposematic signals (warning signals) to potential predators, that they can give a nasty sting. Due to the success of the bee with its aposematic coloured stripes, other insect species have adopted bright colouration or stripes/spots in what is called a "Batesian mimicry"; this deceives predators, making them think that the prey in question is a bee, and so deters the predator. 

Fun fact: bees beat their wings 200 times per second!

Threats and Conservation efforts:

Bumblebees are at risk from numerous threats, including attack by parasites and pathogens, or predators. Bee-eaters, shrikes, great-tits, European honey-buzzards, badgers (who may dig up nests) and crab-spiders are all considered predators of the humble bumblebee. In addition to this, as an example of the parasites which affect bumblebees, Locustacarus buchneri (tracheal mites) cause respiratory issues in the bees, and deformed wing virus affects approx. 11% of the British bumblebee population, which causes deformities in wing development.

It is a well-documented fact that bumblebee populations the world-over are in decline, and this is a major cause for concern, specifically because bees are such important pollinators and "caretakers" of the countryside. In the UK, three species of native bumblebee have become extinct, eight are in severe decline, and just six of the 25 native bumblebee and cuckoo-bumblebee species remains relatively widespread. Bees have huge economic and environmental value in their pollinating abilities for both crops and wildflowers. Causes of this decline may include changes in land-use, resulting in a decline in suitable habitat and suitable food resources, increases in pathogen and pest numbers, an increase in the use of fertiliser and pesticide chemicals (in particular, neonicotinoids) which harm the bees, and climate change.

The effects of a loss in bumblebee numbers could result in less efficient pollination of wildflowers and other flora, as well a reduced agricultural output, with knock-on effects on the economies of the world. In order to reduce the loss of bumblebees in the UK, a charity named "The Bumblebee Conservation Trust" was registered in 2006. As part of its efforts to save Britain's bumblebees, the charity sought to reintroduce the short-haired bumblebee in 2009-2010. The bees were released in Dungeness (Kent), and by 2013, short-haired bumble-bee workers were recorded within the area, evidencing that nests had been established. In addition to reintroductions of species previously extinct in the UK, charities such as the one mentioned previously, along with the RSPB and Natural England, are implementing agri-environmental schemes (such as the Environmental Stewardship Scheme - ESS). In 2008, Scotland established a bumblebee sanctuary at Loch Leven National Nature Reserve, which was a world-first!