Insect pollinators are vital for ecosystem health and functioning, both in their native environments and in agricultural systems.
Effects of wind on pollinator activity
Honeybees are the most recognized insect pollinators and are valued because of the wide variety of crops they pollinate. Honeybees can forage as far away as 3-5 miles from their colony although most foragers tend to stay within a few hundred yards of the colony if it is in or adjacent to a crop with adequate food rewards (nectar and pollen).
Honeybees do not forage in rain or in wind stronger than 12 mph. A honeybee normally flies at a speed of 18 mph empty and 15 mph carrying a load (e.g. pollen, nectar and water). However, when agitated and empty, honeybees can fly 20-21 mph.
They cannot carry a load upwind against much more than a 15 mph wind. As wind speed increases, the number of foragers declines in a linear relationship and foraging behavior may change.
In some publications, researchers report that when wind speeds reach 15-20 mph, most bees will stop visiting blossoms in the trees and will work blossoms on the orchard floor instead. A strong prevailing wind may force foraging bees down to the end of a row of hives in an apiary or to downwind apiaries in a field or orchard setting.
Beekeepers sometimes exchange upwind hives with the downwind hives to equalize the populations during the pollination season.
Effect on pollen fruits
Strong winds may injure flowers and cause loss of pollen. High temperatures, wind, and low humidity may cause desiccation of the style and reduce the receptive period of the blossom for pollination. If the style dries too quickly (before the pollen- tubes have a chance to grow down to the ovary) fertilization can be affected, even if pollination has occurred.
For fruit with more delicate flowers, such as prunes, a few days of dry winds can destroy crop potential. Winds reduce cross-pollination in prunes, and in some cases apricot, when the desiccated pollen clumps on the dehisced anthers make it more difficult for bees to collect.
Effects of wind on landing speed
Wind could also affect insects’ landing patterns or locomotory behaviors that precede landing – including the direction from which insects approach a landing target, and changes in body attitude and velocity.
Wind increases drag forces on the body and wings of flying insects, and this may make fine control of body attitude and flight speed more challenging. Wind could also restrict the range of angles from which an insect can approach a target, as flying crosswind is likely to be more challenging than flying upwind
Effects of Wind on Insect pollinators
Wind energy is a growing alternative energy source in the United States and abroad, and Wyoming is considered to have exceptional wind resources. In Wyoming, 43% of federally owned land is considered fair to excellent for conversion to wind energy developments.
With over 7 million hectares of Wyoming lands administered by the BLM, land conversion for the development of wind energy may have far-reaching consequences for both ecosystems and the public. Current proposals for wind energy developments in Wyoming estimate that wind farms operating on 61,107 hectares of BLM land will produce 4,500 megawatts of electricity, enough to power over one million homes.
Although wind power may be an environmentally sustainable alternative to other energy sources, construction and operation of wind turbines may have substantial environmental impacts.
The presence of wind farms may strongly effect insect pollinator communities with potentially cascading ecosystem effects. Insects represent 80 per cent of the world’s species, dominate terrestrial ecosystems, and provide critical ecosystem services such as food for animals and pollination. Insect pollinators are vital for ecosystem health and functioning, both in their native environments and in agricultural systems.
Large numbers of insects may be killed by wind turbines, given that residue from insect carcasses on turbine blades creates drag that can decrease efficiency between 25-50 per cent. Turbine color and the heat generated during operation may attract insects and, in turn, bats and birds that feed on insects. Indeed, the majority of bats and birds killed by wind turbines are insectivorous species.
Wind pollination and insect pollination
Pollination systems of Salix miyabeana and Salix sachalinensis were studied at a riverside in northern Japan in order to measure the balance of wind pollination and insect pollination.
In the wet and cloudy spring of 1996, clones which obtained high seed set depended more on insect pollination for both species, whereas in the dry and sunny spring of 1997, such clones depended more on wind pollination for S. miyabeana. Because the efﬁciency of wind pollination seemed to be more sensitive to ﬂuctuating weather conditions than insect pollination, insect pollination was considered to play an assurance role for seed production in these willows.
Entomophily and anemophily
Entomophily and anemophily are two main pollination systems in vascular plants. Entomophily is dominant in angiosperms, and it has evolved from anemophily, which is a common system in gymnosperms.
Anemophily could be effective when the density of compatible mates is high, ﬁltration of aerial pollen by plant canopies is less, and activity of pollinators is low. There are some reports indicating that willows have two pollination systems, anemophily and entomophily.
Willows are often dominant on riversides, volcanoes, or alpine and subarctic regions. Willow species are considered to have evolved from anemophilous ancestors and have secondarily reacquired the entomophilous system.
Although many studies have demonstrated that entomophilous pollination dominated in northern willow species, a few studies suggested that wind pollination plays a facultative role.
This article is jointly written by Faheem Shoukat and Muhammad Mujahid from Department of Entomology, MNS- University of Agriculture, Multan, Punjab, Pakistan.