Bees and Avocado: A Vital Partnership

One of nature’s most fascinating and essential partnerships exists between avocado production and bees. It is nearly impossible to grow avocado on a commercial scale without bees. At the heart of this vital connection lies the unique and complex flower structure of the avocado tree.

The Unusual Structure of Avocado Flowers

Avocado trees have a unique flowering system called synchronous dichogamy (simultaneous gender change), which makes self-pollination difficult.

Timed Gender: An avocado flower has both male and female organs, but these organs are not active at the same time.
Type A and Type B Trees: Trees are divided into two types based on their flowering pattern. The flowers of a Type A tree open as female in the morning, close, and then open as male in the afternoon of the next day. The flowers of Type B trees work in the exact opposite way.
Necessity of Cross-Pollination: Due to this timing difference, the pollen of Type A and Type B trees must be transferred to each other at the right time for fruit set.

Why Bees Are Indispensable

Avocado pollen is heavy and sticky, so wind pollination (pollen carried by wind) is quite inefficient for avocado trees. This is where bees come in.

Effective Carriers: Honeybees, while flying from flower to flower to collect nectar, carry pollen stuck to their bodies, ensuring cross-pollination between Type A and Type B trees.
Fruit Set: In avocado orchards actively pollinated by bees, fruit set and total yield increase significantly. In cases where bees are prevented from accessing the orchard, fruit yield decreases to almost nothing even if the trees flower.

The Economic Dimension of the Partnership

In industrial agriculture, avocado growers bring in rented bee hives to their orchards during the flowering period. This system is beneficial for both parties:

A plentiful and high-quality avocado harvest for growers is guaranteed.
Bees find a rich source of nectar, and beekeepers get the opportunity to produce special avocado honey, which is dark in color and has a molasses-like taste, obtained from avocado flowers.

This timed gender change (dichogamy) in avocados, or the absolute dependence on insects/natural carriers, is also observed in other fruits in nature with different strategies.

Pollination Strategies in Other Fruits

Here are other key fruits with such mandatory pollination and gender mechanisms:

Similarities in Timed Gender (Dichogamy)

Walnut and Pecan A mechanism very similar to that in avocados is also found in walnuts and pecans. Both male and female flowers are on the same tree but mature at different times to prevent self-pollination. The main difference from avocado is that pollen is primarily carried by wind, not by bees. Nevertheless, for a successful harvest, it is essential to plant different varieties that flower at different times side by side.

Dioecious (Separate Sexes) Trees

Kiwi In kiwi, the situation is more pronounced than in avocado; the sex of the trees is fixed and completely separate. A kiwi tree either produces only male flowers or only female flowers. For commercial production, it is mandatory to plant a certain proportion of male trees among female trees (usually 1 male for every 6-8 females) to get fruit. Wind is also insufficient for pollen transfer, and bees or other pollinating insects are absolutely necessary.

Pistachio Similar to kiwi, trees are either completely male or completely female. Male trees produce pollen, while female trees bear fruit. In orchard setup, male trees are strategically positioned taking into account the prevailing wind direction.

The Most Special Pollination Partnership

Fig An even more complex and specific relationship than the avocado-bee partnership is seen in figs. The fig we eat is not an outward-opening flower but a closed cluster of flowers growing inwards. Due to this closed structure, wind or ordinary bees cannot pollinate. This job can only be done by the special “fig wasp” (ilek arısı in Turkish), which can enter through a microscopic hole at the bottom of the fig. The fig tree and the fig wasp cannot survive or reproduce without each other.