Ecosystem services, such as pollination are often overlooked until they are damaged or lost. They are usually impossible to replace. Many plants rely on insects to pollinate their flowers and so complete their reproductive cycle. The contribution of wild pollinators and cultured Honeybees is difficult to separate, however we do know that large numbers of flowers are ‘buzz-pollinated’ such as tomatoes by bumblebees, and many flowers are only pollinated by particular types of wild pollinators and not pollinated at all by honeybees.
It is estimated that 84% of EU crops (valued at £12.6 billion) and 80% of wildflowers rely on insect pollination. Well-known wild pollinators include bumblebees and other bees (250 species), butterflies and moths (2200 species), flies (6700) and various other insects such as beetles and thrips.
| Habitat loss and fragmentation 62% of wildflowers are pollen transmission limited (i.e. more pollination would mean more seeds and then more flowers). There is evidence that insect pollinated plants are declining faster than wind and water pollinated plants. The probable reasons for the decline in pollinators are linked to the intensification of the countryside. This intensification leads to the loss of flower-rich semi-natural grassland, (including field margins, road verges and meadows) where many wild pollinators nest and feed. This loss can arise through the use of herbicides or as result of eutrophication resulting from atmospheric nitrogen deposition and the excess use of nitrate fertilisers. |
Pollinators and pesticides
Crop protection products such as insecticides undergo a number of tests prior to their introduction. Currently these tests do not cover systematic pesticides that are applied as seed dressings. These systematic pesticides act by contaminating plants tissues and are often applied as seed dressings, thus allowing a low level but long term exposure to the pesticide. Sub-lethal effects are those that do not immediately lead to the death of an invertebrate but alter the behaviour or other attribute leading to a population decline.
Pesticides that may impact on social insects, such as bumblebees and honeybees, which have complex behaviour and reproductive systems, need through testing to adequately assess their impact. Without standardised methods parts of the life cycle may not be tested. In addition, the number of invertebrate groups tested is typically very limited and some of the potentially most sensitive groups being overlooked.
The lack of independency and transparency in research for the crop protection products approval system is a cause of concern as it can not be widely assessed. There is a need for a system that is more open to wider criticism and reassessment and that is responsive to new independent research.
These issues are further illustrated by the testing and use of neonicotinoid pesticides in the UK. Neonicotinoids are a class of insecticides, first used in agriculture in the mid 1990s, and now widely used to control soil, seed, foliar, timber and animal pests. The most common active ingredients approved for use in the UK are Imidacloprid and Clothiandin.
An assessment of the approval process showed inadequate testing with regard to sub-lethal impacts with many important aspects of the honeybee life cycle not tested. There were also differences in the testing of long term toxicity (chronic) effects between the approvals testing and independent research, with the independent research showing more significant impacts. A number of existing independent research studies which were reviewed during the approval process showed that negative impacts were invalidated and a review of these studies found the invalidation grounds to be inadequate.
The approval system as it stands is not adequate as it currently allows products onto the UK market that contain active substances that are potentially harmful to a range of invertebrate pollinator species. This is directly in breach of the objectives of directive 94/414 as they are potentially having an unacceptable effect on the environment and could lead to a widespread decline in invertebrate pollinators. Increasing evidence of the impact of neonicotinoid pesticides on non-target species has lead to their withdrawal in France, Germany, Italy and Slovenia.
The European Framework Directive on the sustainable use of pesticides has the potential to greatly improve the use of pesticides and provide pesticide reduced and free areas. If this directive is used to its full potential and applied in an effective and innovative way it will help to reduce the current declines in pollinators caused by pesticides. For more information on Buglife's involvement on this topic please click here.
| The Varroa mite The Varroa mite (Varroa destructor) is a parasitic mite, whose natural host is the Asian honeybee (Apis cerana), but can now be found on the Western honeybee (Apis mellifera), which has no natural defences against it, and eventually the mite will kill infected colonies if left untreated.  | | Veroa mite (Varroa destructor) © Brian, Wikipedia Commons | This mite was first discovered in the UK in 1992 and has since spread to infest honeybee colonies throughout the country, so much so that bee-keepers routinely treated their hives with pyrethroid-based pesticides to reduce mite numbers. Unfortunately, the mite has now developed resistance to these pesticides worldwide and resistant forms are spreading throughout the UK. Bee-keepers are now being forced to look at different chemical and biotechnological techniques to reduce infestations. |
