Pachyanthidium bees

Summary

Honey bees are not the only bee species that are significant for human wellbeing. Pachyanthidium 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. Females have a sting, but they are not aggressive and will only sting if handled. Pachyanthidium bees nest in natural cavities and live independently of other bees (i.e. they are solitary). They have long tongues which allow them to feed on deep as well as shallow flowers. 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.

Scientific Classification

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Hymenoptera

Family: Megachilidae

Subfamily: Megachilinae

Tribe:  Anthidiini

Genus: Pachyanthidium Friese, 1905

Species in the Genus

The genus Pachyanthidium is a group of solitary bees in with about 20 species described worldwide. They are likely to occur throughout Africa.

Species in Kenya, Tanzania & Uganda

Five described species have been recorded inKenya , Tanzania and Uganda (Eardley and Urban 2010). It is likely that more species will be found as a comprehensive list of Pachyanthidium species occurring in East Africa has not yet been produced.

Description

Pachyanthidium 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. Pachyanthidium bees have long tongues and can feed on deep or shallow flowers. All Pachyanthidium bees in East Africa are pollen-collecting bees. In East Africa, they are known to visit flowers of crops but they appear to mainly visit wild flowering plants. Their importance as effective pollinators in agriculture has yet to be established. However, they may be effective pollinators of wild plant species; hence the need to protect them.

Possible Causes of Confusion

Some insect species can be mistaken for Pachyanthidium bees. These include other bee species in the tribe Anthidiini (which includes Pachyanthidium and Afranthidium bees ). They can be distinguished by microscopic characteristics that are described in the key that accompany these fact sheets. Afranthidium bees can also be confused with some flies and wasps. Flies are different in that they have large eyes and two wings while bees have smaller eyes and four wings. In addition, most flies that may be confused with these bees do not collect pollen from flowers. Wasps have a constriction (“waist?) at the junction of their abdomen and thorax which is absent in bees.

Distribution in Kenya, Tanzania & Uganda

Pachyanthidium bees are found in most districts/regions of Kenya , Tanzania and Uganda . However, published information on their distribution in these areas is lacking. 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

Pachyanthidium bees can be found in various habitats (land-uses) in East Africa such as grasslands, natural forests, marshlands, protected areas, farmlands, rangelands, woodlands, woodlots (forest plantations), along river edges (riparian areas) and in coastal areas. In Uganda , these bees have been noted as very common in semi-arid zones.

Nesting

Pachyanthidium bees live independently of others (i.e. they are solitary). Pachyanthidium bees build their nests in sheltered locations in pre-existing natural cavities such as burrows, crevices and hollow twigs that can be found in less disturbed and dry habitats.

Crops Visited

Pachyanthidium bees visit a variety of flowering crop species belonging to different plant families in East Africa. In Uganda they have been seen visiting a few crops such as cowpeas and simsim (sesame).

Other Plants Visited

Pachyanthidium bees occurring in East Africa visit a range of wild plant species (trees, shrubs, herbs, weeds, lianas) found in different habitats. These bees preferentially visit plant species with small purple and blue, milk cream 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 likely to be pollinators and thus contribute to increased agricultural productivity and the conservation of the natural biological diversity of the region.

Threats

InEast Africa, Pachyanthidium 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. Pachyanthidium bee populations in East Africa are likely to be affected by pests and diseases but information on this subject is lacking. 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 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 also indirectly play a major role in the protection of pollinators. 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, Gikungu MW and Schwarz MP (2009) Bee conservation in Sub-Saharan Africa andMadagascar: diversity, status and threats. Apidologie, 40: 355–366.

2. 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

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

4. 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: [email protected]