Ceratina bees

Summary

Honey bees are not the only bee species that are significant for human wellbeing. Ceratina bees are a group of native bee species that do not produce honey but are important pollinators of crops and wild plants. Ceratina bees are not aggressive but can sting for defence. Ceratina bees are usually dark with a shiny or metallic appearance, sparse-haired and medium-sized. Most species of Ceratina bees live independently of others (i.e. they are solitary) but some species live in small colonies and a few appear to have nests with several adult females. They usually nest in woody materials in various locations mostly in shaded environments. 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)

Small carpenter bee (English) – they share this common name with bees of the tribe Allodapini.

Scientific Classification

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Hymenoptera

Family: Apidae

Subfamily: Xylocopinae

Tribe: Ceratini

Genus: Ceratina Latreille, 1802

Species in the Genus

Ceratina is a genus that comprises of about 350 species distributed throughout the world. Ceratina bees (small carpenter bees) are closely related to the more familiar (“large?) carpenter bees (Xylocopa species).

Species in Kenya, Tanzania & Uganda

More than 20 species have been recorded in different habitats inKenya, Tanzania and Uganda (Eardley and Urban 2010) though a comprehensive list of Ceratina species for the region has not yet been produced. Three of the most common species of Ceratina bees in East Africa are Ceratina lineola, Ceratina lunata, and Ceratina rufigastra.

Description

Ceratina bees are not well known by local people (including farmers) inEast Africa. These insects are not usually recognised as bees by local people in East Africa , where the name bee is generally thought only to apply to honey bees. Ceratina bees are usually dark, shiny, even metallic bees, with relatively little body hair and a weak pollen carrying structure (scopa) on the hind tibia (second leg segment). Most species have some yellow markings, mostly only on the face but also often elsewhere on the body. It is easy to identify some Ceratina bee species by their size and colour, by which they can be characterised as “blue shining?, “black shining?, etc.

Possible Causes of Confusion

Some insect species can be confused with the larger Ceratina bees: These include species that are frequently seen on flowering plants during peak blooming periods such as leafcutter and dauber bees ( Megachile bees), halictine bees and small beetles (Coleoptera species). Female Ceratina bees can be distinguished from Megachile bees by the fact that they carry pollen on the hind legs whereas Megachile bees carry pollen under the abdomen . Ceratina bees can be distinguished from halictine bees by their mouthparts (Ceratina bees have a long glossa – “tongue?) and their hind wings (which have a tiny jugal lobe – posterior area of wing). Beetles have hardened fore-wings (elytra ) while bees have four membranous wings. Smaller Ceratina bees can be confused with Allodapula bees (also sometimes known as small carpenter bees). Ceratina bees are mostly well sclerotised (“armoured?) and robust, and they are mostly black or metallic blue. Allodapula bees are weakly sclerotised and fragile looking.

Distribution in Kenya, Tanzania & Uganda

Ceratina bees are found in most districts/regions of Uganda, Kenya and Tanzania (Eardley and Daly 2007; Eardley, Gikungu and Schwarz 2009).

Habitats

Ceratina bees can be found in various habitats (land-uses) in East Africa such as grasslands, natural forests, wetlands, marshlands, open habitats, protected areas, farmlands, rangelands, woodlands, woodlots (forest plantations), riparian areas.

Nesting

Most Ceratina bee species are solitary bees that make nests in dead wood, stems, or pith. However, a number are subsocial, with mothers caring for their larvae, and in a few cases where multiple females are found in a single nest, daughters or sisters may form very small, weakly eusocial colonies (where one bee forages and the other remains in the nest and lays eggs). Most species occurring in East Africa nest in self-made tunnels in woody materials on the ground, in the soil and in walls of abandoned houses or in the soil.

Crops Visited

Most Ceratina bee species in East Africa collect nectar and pollen from various flowering crop species belonging to different plant families (are polylectic) while a few visit a narrower range of plants (are oligolectic). These bees are efficient pollinators of crops such as beans, cowpeas, simsim (sesame), apples and coffee.

Other Plants Visited

InEast Africa, Ceratina bees visit various plant species, notably those in the Fabaceae, Malvaceae, Rubiaceae and Asteraceae families. In East Africa, Ceratina bees are wild bees (not yet domesticated but with potential for being domesticated as efficient pollinators of many crops - “ceratiniculture?) that visit various wild plant species (trees, shrubs, herbs, weeds, lianas) found in different habitats. These bees preferentially visit plant species with small yellow, white, green, milk-cream and purple coloured flowers.

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, Ceratina 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. Ceratina bee populations in East Africa are likely to be affected by pests and diseases but information on this subject is lacking. Wood collection can affect nesting sites of wood-nesting species. 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 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 hiding 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. Wood collection should be managed to conserve nesting sites wood-nesting species and trampling by people and livestock and tilling should be managed to conserve the nesting sites of soil-nesting species. 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 Daly HV (2007) Bees of the genus Ceratina Latreille in southernAfrica (Hymenoptera: Apoidea). Entomofauna 13: 1-96.

2. Eardley CD, Gikungu MW and Schwarz MP (2009) Bee conservation in Sub-Saharan Africa and Madagascar: diversity, status and threats. Apidologie, 40: 355–366.

3. Eardley CD, Kuhlmann M and Pauly A. (2010) The Bee Genera and Subgenera of sub-Saharan Africa. ABC Taxa vol 7: i-vi, 138 pp. http://www.abctaxa.be/volumes/vol-7-bees

4. Eardley CD and Urban R (2010) Catalogue of Afrotropical bees (Hymenoptera: Apoidea: Apiformes). Zootaxa, 2455: 1–548.

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

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