For this post I’m delighted to introduce an article provided by guest contributor Saikat Basu. Saikat is an Indian scientist currently working in Canada at the Department of Biological Sciences, University of Lethbridge. This paper, which was co-written by W. Cetzal-Ix from the Instituto Tecnologico de Chin Calle in Mexico, is another great example of international collaboration on an issue with global implications.
As Saikat reports, bees are important not only as a prime pollinator of agricultural and natural vegetation, but also as a source of revenue for many Mexicans through honey produced from beekeeping. Many countries have recently seen dramatic reductions in bee populations; in Mexico some of the chemicals used by beekeepers to protect bees may actually be contributing to the bee population decline.
This article analyses the situation and provides guidance on appropriate solutions.
Pollinators are an important group of natural biological agents that are responsible for the transfer of pollen grains from the anther to the stigma of flowers for the purpose of cross pollination among plants. A vast majority of agriculturally important crop plants, vegetables, fruit trees and orchard plants are dependent on natural pollinators for the purpose of cross pollination. Hence, biological pollinators are important natural agents that are intimately associated with the agricultural economics as well as the sustainability of the local ecosystems. When we discuss about pollinators we are mostly focused on insect pollinators like the bees (honey bees, native/wild/indigenous bees), moths and butterflies, certain species of pollinator friendly flies and beetles. However, it is important to mention that natural pollinators also include some species of molluscs (snails and slugs), small birds (for example hummingbirds) and small mammals (like pollinator bats) in addition to insect pollinators (Basu and Cetzal-Ix, 2017).
Mexico, located at the southern most tip of the continent of North America has distinct geographical, geological and biological variations; and different agro-climatic regimes stretching from the north to the south and also from west to east between pacific to Atlantic coasts. As a consequence, Mexico is blessed with tremendous biodiversity of all life forms including insects. The country reports significant diversity of all kinds of natural pollinators including introduced honey bees and indigenous Mexican native bees. The wide diversity of pollinator bees and their host plants in Mexico has been presented in Table 1 and Figure 1. The bees contribute significantly towards Mexican rural economy with over 40,000 local bee keepers reported to be controlling over two million bee colonies producing high quality honey and bee wax; that is both consumed locally and exported overseas. Beekeeping contributes significantly in earning foreign exchange for Mexico. Unfortunately, over the past two decades, the bee populations in Mexico has been showing serious decline impacting honey and bee wax production; and also significantly impacting livelihood for a substantial part of the rural populations dependent or associated with beekeeping.
Factors contributing towards rapid decline in bee populations
For successful bee management, Mexican beekeepers commonly use a number of chemicals to protect bee colonies against possible diseases and parasitosis and/or for food supplement during low or no flowering period. However, improper use and/or unfortunate over applications of pesticides in these activities can easily contaminate honey and/or bee wax; and are toxic to both bees and beekeepers (Martínez-Puc et al. 2016). The contamination is mainly due to the treatment of diseases and parasitosis arising from residues applied mainly in the control of Varroosis (caused by the mite Varroa destructor Anderson & Trueman) or small hive beetle (Aethina tumida Murray). The main chemicals used in Mexico to control these are fluvalinate (Apistan®), flumethrin (Bayvarol®) and amitraz (Apivar®). These pesticides, together with parasitic diseases and poor nutrition; have been partially responsible for the problem of Colony Collapse Disorder of bees.
Nevertheless, it has been identified that the plant pollen that Mexican bees collect to feed their colonies are also contaminated with pesticide (insecticide) and/or fungicide over application by local crop producers; causing death and destruction in bee colonies and making them too weak and highly susceptible towards infection by potential bee parasites (Woody, 2013). The death of bees has been alarming with thousands of local Mexican apiaries turning non-productive and is fast disappearing with serious concerns both for economists and bee ecologists alike. Mexican beekeepers point out that the death of bees (and other pollinator insects) is due to the indiscriminate use of excessive agro-chemicals and insecticides (neonicotinoids) to counteract pests in crop production areas adjacent to the apiaries and local forests as well as run the serious risk of contaminating honey and/or wax from the treated bee colonies (Martínez-Puc et al. 2016).
Among other associated factors that have led to the death of bees are attributed possibly to Global Warming and Climate Change (pers. Comm., local beekeepers). However, substantial filed research and field data is essential before any conclusive statement could be made regarding this. An important alternative to counteract the death of bees by pesticides is the training of Mexican beekeepers and farmers to implement alternative and environmentally friendly treatments to reduce the risk of pests and resistant pests. It is important to avoid excessive use of pesticides (insecticides) that on the one hand contaminate local crops, trees and fruit orchards; and on the other hand significantly contribute towards the death of local Mexican bees in alarming proportions.
Need for establishing local Bee Sanctuaries across Mexico
One of the successful conservation efforts necessary for efficient bee conservation is the creation of suitable and highly enriched bee habitats that can provide food, forage and shelter for different native bee species across the various seasons. Such bee habitats or pollinator habitats (as they also attract other insect pollinator species in addition to native bees) is important for sustaining and extending the bee foraging period beyond the beginning and end of the crop production season in various agro-climatic regions of North America including Canada; with limited foraging period for the local, native bees (Basu and Cetzal-Ix, 2017).
Such well designed and highly efficient bee or pollinator seed mixes can be used at appropriate places to create suitable bee/pollinator patches or bee/pollinator gardens or bee/pollinator sanctuaries for native bees and other insect pollinators. Such bee sanctuaries could be established along farm fence lines, water bodies, unused or hard to access part(s) of a farm, organic farming sites, along irrigation canals, meadows, highways, dividers, city and municipal parks and gardens, corporate lawns and gardens, undisturbed parts of golf courses, lawns or gardens adjoining government buildings and warehouses, private lawns, and backyard gardens, and unused or undisturbed areas under various irrigation districts (Basu, 2017; Basu and Cetzal-Ix, 2017).
Such pollinator gardens or bee sanctuaries established at regular distances can have positive impacts on the population dynamics of native bee species that usually prefer moving within a distance range of 20-200 m for the purpose of foraging to collect pollen and nectar from flower species representing divergent plant families. Bright color, distinct shapes and smell attract foraging bees and other insect pollinators (such as moths, butterflies, some species of flies and beetles) to visit these pollinator-friendly flowers for sustaining their hive populations. It is advisable to avoid spraying any form of pesticides or insecticides in such bee habitats to allow bees to thrive, sustain, build their hives and nests close by without the danger of accidentally killing them by using aggressive chemicals.
SKB gratefully acknowledges the research funding and support provided by Performance Seed, Lethbridge Alberta, Canada for the Pollinator Mix project. WCI would like to acknowledge the support from TecNM Project (CHN-LGAC-03-14)“Caracterización de la flora nativa de importancia apícola en Campeche: estrategia para incrementar la productividad en las colonias de abejas melíferas en periodos críticos de floración”.
1Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4; 2Instituto Tecnologico de Chin Calle 11 entre 22 y 28, Colonia Centro Chiná 24050 Campeche, Mexico; *corresponding author: firstname.lastname@example.org
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