Crop yields

animated_gif_bees_06  Crop yields are linked to successful pollination rates

Pollination is the transfer of the microscopic male pollen particles to the female parts of the plant which is done principally by wind or insects (mainly bees). Pollination is nature’s way of the plants having sex to make new plants. Fruit bearing crops and other plants must be pollinated in order to create seed and fruit to attain good crop yields.

Bees and plants have evolved their mutually beneficial relationship over 100 million years. The plants make flowers to attract the bees and the flowers offer tiny drops of sweet fragrant nectar as a nutritious ‘reward’ to the bees for visiting. As the bees land on the flowers they climb over the male pollen producing parts of the flower picking up pollen on the way. When they visit other flowers they climb past the female parts and deposit pollen which fertilises or pollinates that flower.

The bees are sipping tiny droplets of nectar at the base of the flowers, and they will make the nectar into honey as they fly back to the colony. On the rear legs of the bee are ‘pollen baskets’ so the bee can also take some pollen back to their colony as food.

In the Philippines 75% of the food crops need insect (mainly bee) pollinators for sufficient successful pollination, and these include coconuts, mangos, coffee, peppers, star fruit, kiwi, cashew, rambutan, macadamia, sunflowers, papaya, lychee, guava, watermelon, cucumber, squash, gourd, luffa, avocado, pechay, cowpea, cocoa, passion fruit, oil palm, beans, tangerine, tomatoes and crops such as cotton. (Wind pollinated crops such as sweetcorn, rice, and sugarcane are produced in greater volumes.)

This means that to get good crop yields there needs to be a good population of bees available to visit the many millions of flowers for all the different plants, which also includes non-crop plants. (Depending on the plants in bloom bees may prefer certain flowers.) If there are not enough bee pollinators when a crop comes into bloom only some of the flowers will be pollinated and so the yield will be lower than it could be.

Mango and coffee yields

In the Philippines the most prolific pollinators are the Ligwan and Putyokan honeybees, and it is these honeybees that are being killed off by destructive honey hunting, and also by the poor use of pesticides and habitat loss. This is resulting in noticeable year on year reductions in crop yields.

Generally in nature ‘cross-breeding’ will make healthier offspring, and cross-pollination means that the seeds and fruits will generally be more vigorous and less suspectible to disease. Plants can also ‘in-breed’ or self-pollinate (sometimes called ‘self-fertile’) where the pollen fertilises the female stigma from the same flower or on the same plant.

Close up of cotton pollination

From an evolutionary point of view, on the whole it is to the plant’s advantage to breed with other plants of the same species and ensure that a healthy genetic diversity is maintained, since these plants are more likely to survive.  By using animals (such as bees) to spread pollen there is a good chance that pollination might occur.  Bees help both self-fertilisation and cross-fertilisation and hence plants maximise their seed and fruit production. (Fruit is another way of seed dispersal.)  Bees in particular enable plant flowers to efficiently spread their pollen to flowers on the same plant and also to flowers on plants some distance away.

Wind pollinated plants such as rice produce large quantities of pollen with the chance that some pollen grains will land on female stigmas.


As can be seen with rice yields, there is no evident problem with wind pollination in mono-cropped agriculture and the Philippines has advanced its yields along with other Asean countries. This would have been a result of plant breeding producing new varieties, the use of pesticides and other chemicals plus a development of cultivation methods.

Although plant breeding has altered some of the wild plant characteristics, there are some very important underlying principles that still apply in most crops. (There are exceptions such as banana, but this is another story since banana clones are potentially vunerable to a disease outbreak.) The use of ‘self-fertile’ varieties, hybrid varieties and GM varieties has also complicated issues sufficiently to warrant many more posts.

Hoping that the latest variety will automatically lead to better yields is mistakenly forgetting that underlying so many crops is the basic biological need for successful pollination, if the crop is producing a seed or fruit of some kind. There is no shortage of wind in the Philippines and so pollination is taken for granted with crops such as rice, sweetcorn and sugarcane.

It is different with insect pollination, principally done by bees since we need to be aware of the pollination environment, and that environment has largely been ignored in the Philippines. A lack of engagement by key Government departments and insufficient education has resulted in a very poor awareness of this crucial aspect leading to the degrading of the pollination environment over many years. Alongside this the dwindling yields of many bee pollinated crops is becoming increasingly evident.

Even the latest ‘self-fertile’ hybrid coffee varieties are shown to have very significantly improved yields with sufficient bee pollination. (1) In the Philippines many millions of rural people depend on crop varieties that are highly dependant on sufficient insect (mainly bee) pollination, but don’t even realise it! Combine this with a rural situation that has declining bee populations in many areas – largely due to a lack of awareness. Despite considering climate change issues and various initiatives to improve varieties, fertilisers and cultivation methods, it might be expected that there would still be an apparantly unstoppable dwindling of yields with bee associated crops.

Mango and coffee yields

I have repeatedly shown these same statistics deliberately to remind the reader of the situation – there are many other charts and comparisons that could be made.

Squash is commonly grown in the Philippines throughout the year. (3) It is usually grown in home gardens and commercial scale for its immature fruits, young shoots, flowers and seeds. In some places, intercropping squash with other crops like corn, sugarcane and coconut is practiced. It is commercially cultivated in Ilocos Region, Cagayan Valley, Southern Tagalog and Bicol Region. The provinces producing semi-commercial scale are Davao, Leyte, Nueva Ecija and Batangas. Like other cucurbits, squash is recognized as an important source of vitamins and minerals.

As the ‘High Value Crops Development Program’ website (3) guide states… Bees are the most common agent of pollination for cucurbit crops. Therefore, an ample supply of honeybees should be introduced into production fields to enhance and ensure pollination. Poorly pollinated fruits will have poor development which usually results in unmarketable fruits. (It is noted that the provinces where squash is currently commercially cultivated have probably good bee populations and a greater proportion of beekeepers, than many other regions in the Philippines.) The HVCDP website (3) guide also states… To increase fruit setting when insect pollinators are few, hand pollinate by inserting the male flower of the same age to the female flower between 6:00 and 8:00 in the morning.

In the ‘Squash Pollinators of the Americas Survey’ (2) an explanation is given of bees and their importance and use in big agricultural squash production. What are the prospects for large scale efficient agricultural squash production if there are insufficient bees in many islands and regions of the Philippines to produce good squash yields?

Currently it appears that the fundamental process of pollination for various crops is not being fully considered by the Philippine Department of Agriculture. The ‘Philippine Coconut Authority’ (7) and the ‘High Value Crops Development Program’ websites do not mention the need for pollinators – with the single exception of the squash crop. (The HVCDP for example attributes declining production of mangos and coffee to several causes, but does not mention pollination issues.) This website links directly to a great many references including the Food and Agriculture Organisation (4) (5) which repeatedly demonstrate the importance of considering the pollinator environment – and this is now impacting on millions of farmers in the Philippines.

Philippine coconut authority search

Pollination issues are not fully considered (0 results found) by The ‘Philippine Coconut Authority’ (7) and other Department of Agriculture information websites.

The Philippines is not the only country with pollination issues. India (8) for example has a recognised ‘pollination crisis which is hitting vegetable farmers’ – at least in India there is better recognition of the issues involved and therefore more prospects that corrective action may be taken. Unfortunately it appears that the Philippine ‘pollination crisis’ is probably more significant than the issues identified in India.

During the history of humankind, bees have been doing the vital job of pollinating for free, but it is becoming evident that the Philippine rural communities can no longer take this service for granted. Comparisions to other countries such as Vietnam indicate a different scenario where they are not encountering the same issues – where plentiful bees produce 300 times more honey than the Philippines and coffee yields are 5 times greater than the Philippines.

There is no evident disadvantage to re-establishing the native bees in the Philippines and improving the pollinator environment, but the advantages are potentially enormous.


1) Coffee pollination: Honeybees boost coffee yields

2) Squash Pollinators of the Americas Survey

3) Squash (hybrid) seed production: Providing a bright future for Sto. Niño farmers

4) Global action on pollination services for sustainable agriculture
Food and Agriculture Organisation

5) Global Pollination Project leaflet by the Food & Agriculture Organisation

6) High Value Crops Development Program (RA 7900)
Department of Agriculture in Philippines

7) Philippine Coconut Authority – Research and Development Branch

8) ‘Pollination crisis’ hitting India’s vegetable farmers

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