Halictus bees

Summary

Honey bees are not the only bee species that are significant for human wellbeing. Halictus bees are a group of native bee species that do not produce honey but are likely to be important pollinators of crops and wild plants. These small, bright metallic bees are not aggressive. However, they can sting for defence. They live independently of others (i.e. they are solitary) or they live in small groups and build their nests in the ground. This fact sheet provides information about these bees to encourage farmers to understand and protect them to help ensure that their crops are effectively pollinated.

From a conservation and agricultural standpoint it is not necessary to recognise all the different bee genera. However, it is important to know that there is a large bee biodiversity. Different bee genera pollinate different plant species, although there is some overlap that acts as a buffer as bee populations wax and wane. For healthy ecosystems, including agro-ecosystems both diversity and abundance in the bee fauna is important.

Common Name (Language)

Mining bees (English)

Scientific Classification

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Hymenoptera

Family: Halictidae

Subfamily: Halictinae

Tribe: Halictini

Genus: Halictus Latreille, 1804

Species in the Genus

There are many species of Halictus bees recorded in different parts of the world. More than 330 species have been recorded representing 15 subgenera.

Species in Kenya, Tanzania & Uganda

Little work has been done on Halictus bees in East Africa, with records of only seven species from Kenya, Tanzania and Uganda (Ascher 2010, Eardley and Urban 2010). The genus urgently needs revision before any species can be reliably identified.

Description

Halictus bees are not well known by local people (including farmers) inEast Africa. These insects are usually not recognised as bees by local people in East Africa , where the name bee is generally thought only to apply to honey bees. Halictus bees are small (smaller than the honey bee) brilliantly metallic, mostly gold-coloured, sometimes green or bluish. Many species are solitary while in others the females share a nest. Halictus bees are mostly pollen collectors. If caught up in people’s clothing or between parts of the body, the females can sting (Michener 1974) although the sting is very mild unless you are sensitive. Halictus are close relative of Lasioglossum and Patellapis (sweat bees), most of whom have similar behaviour.

Possible Causes of Confusion

Halictus bees are easy to identify because they are mostly metallic gold, or very pale green or blue. There are few other bees that are this colour. Other metallic blue or green bees are bright coloured, except a few Ceratina and Nomioides that are similar to Halictus. The former are long tongued and the latter are very small.

Distribution in Kenya, Tanzania & Uganda

There is little information about the distribution of these bees within the East Africa countries. However, considering their habitats and some previous studies (e.g. Martins 2008), representative species of these bees are likely to be found in all ecologies, farmed and protected areas, from coastal lands to highlands. Farmers can assist in reporting the presence of these bees in their neighbourhood. This would improve our knowledge of their distribution in the region.

Habitats

Halictus bees can be found in all habitats (land-uses). Halictus bees are widely distributed and common in disturbed areas and appear to be fairly generalised feeders on annual plants. They are found in forests and farmlands (Martins 2008, Kasina et al. 2009).

Nesting

Halictus bees are solitary bees that construct their nests by burrowing in soil (Michener 1974). They like open areas without vegetation. The literature is old and there is a need for studies to confirm the nesting habitats for these bees.

Crops Visited

Halictus bees visit many different crops though they may be effective on a few specific crops. They have been recorded to pollinate okra, melon and apple (Njoroge et al. 2004). Kasina et al. (2010) showed that the behaviour of Halictus bees while visiting squash flowers can effectively pollinate the crop.

Other Plants Visited

Wild relatives of the crops listed above are visited by these bees. There is also a wide range of plants belonging to many different families that provide pollen to Halictus bees in natural habitats. Halictus bees in Kakamega, Kenya , visited a greater range of plants in comparison to other bees that showed solitary behaviour.

Economic / Ecological Importance

Little information exists on the usefulness of these bees to the lives of the people in East Africa. However, they are pollinators and thus they are likely to contribute to increased agricultural productivity and the conservation of the natural biological diversity of the region.

Threats

InEast Africa, Halictus bees and other bee taxa are threatened by factors such as habitat degradation, agricultural intensification (e.g. replacing hedges with barbed wire fences, and increased use of herbicides which can affect wild flower numbers) and the misuse of insecticides. Halictus bee populations in East Africa are likely to be affected by pests and diseases but information on this subject is lacking. Farming practices that involve over-digging of soils are likely to threaten populations of these bees since they can nest in underground burrows. The lack of knowledge of about these bees and their economic importance by people (de facto custodians of nature) is significant as their conservation and management practices implemented at the farm level will depend to a large extent upon the value that people attach to them.

Conservation and Management Practices

There are now concerted research efforts in the region to develop best practices for conservation and management of bees that are compatible with other good farm practices, to enhance crop production. Theoretically, bee conservation and management is inexpensive and adopted activities can also improve the aesthetic value of the landscape. Such practices involve setting land aside (e.g. a 1-metre strip) in the farmland to host all year round food resources for the bees, as well as safer sites for nesting, mating, resting and refuge from natural enemies. During flowering, farmers should manage pesticide usage carefully to avoid poisoning flower-visiting bees. Farmers should also minimise pesticide drift from the field to adjacent areas. Laws governing registration and use of plant protection products indirectly play a major role in the protection of pollinators. Trampling by people and livestock and tilling should be managed to conserve the nesting sites of soil-nesting species such as Halictus bees. KARI (the Kenya Agricultural Research Institute) is developing protocols for mass rearing of different species of solitary bees. Any successful results from this research will be freely communicated to the public. In addition, KARI is collaborating with other stakeholders to ensure in situ conservation and management of bees for pollination purposes. Much of the work of conserving native bees will be underpinned by raising public awareness of the importance of these species.

Legislation (National and International)

There is not yet any legislation in East Africa that explicitly addresses pollinators. However, there is scattered legislation for the protection of biodiversity particularly that covering environmental protection, protection of wildlife and heritage sites, protection of forests and natural resources such as water catchments. In addition, laws governing registration and use of plant protection products also indirectly play a major role in the protection of pollinators Such legislation, together with market-based mechanisms such as the Good Agricultural Practices (GAPs) codes and practices may help to protect bees albeit incidentally. At the international level, the Conservation on Biological Diversity (CBD) is spearheading strategies to enforce bee management for pollination purposes within the member countries, which include Kenya, Tanzania and Uganda. Farmers should lobby their governments to develop Integrated Pest Management policies that would protect bees and other insects of importance in agriculture.

References

1. Eardley CD and Urban R (2010) Catalogue of Afrotropical Bees (Hymenoptera: Apoidea: Apiformes). Zootaxa 2455:1-548.

2. Kasina M, Nderitu J, Kraemer M, Martius C and Wittmann D (2010) Some aspects of squash pollination in Kenya. KARI Biennial scientific Conference, Nairobi

3. Kasina M, Kraemer M, Martius C and Wittmann D (2009) Diversity and activity density of bees visiting crop flowers in Kakamega, western Kenya. Journal of Apicultural Research, 48 (2): 134-139

4. Kasina M, Kraemer M, Martius C, Wittmann D (2009) Farmers' knowledge of bees and their natural history in Kakamega district, Kenya. Journal of Apicultural Research, 48 (2): 126-133

5. Martins DJ (2008) Pollination observations of the African Violet in the Taita Hills, Kenya. J EA Nat Hist 97 (1): 33-42

6. Michener CD (1974) The social behaviour of the bees. Belknap Press, Cambridge, USA. 5. Michener CD (2007) The Bees of the world, the John Hopkins University Press, Baltimore and London, pp 913.

7. Michener CD (2007) The Bees of the world, the John Hopkins University Press, Baltimore and London, pp 913.

8. Njoroge GN, Gemmill B, Bussmann R, Newton LE, and Ngumi VW (2004) Pollination ecology of Citrullus lanatus at Yatta, Kenya. International Journal of Tropical Insect Science, 24(1): 73–77.

Editors

Théodore Munyuli, Busitema University - Uganda; Muo Kasina, Kenya Agricultural Research Institute (KARI) - Kenya; Juma Lossini, Tropical Pesticides Research Institute (TPRI) – Tanzania; John Mauremootoo, BioNET-INTERNATIONAL Secretariat – UK; Connal Eardley, Plant Protection Research Institute (PPRI) – South Africa.

Acknowledgements

We recognise the support from the Kenya Agricultural Research Institute (KARI), Tropical Pesticide Research Institute (TPRI)Tanzania and Busitema University (Faculty of Natural Resources and Environmental Sciences) - Eastern Uganda. This activity was undertaken as part of the BioNET-EAFRINET UVIMA Project (Taxonomy for Development in East Africa).

Contact

BioNET-EAFRINET regional coordinator: eafrinet@africaonline.co.ke