Increasing Atmospheric Carbon Dioxide is Reducing Bee Survival Rates

Winter Honey Bee Colonies Shrink in Size

by Paul Holowko

Queen bees lay eggs according to the available food and amount of daily light. As the day gets shorter, the colony reduces in size. Bees start moving pollen and honey from outer frames into the brood chamber. The whole colony turns into a ball in the center of the hive. They are trying to keep warm.

Available food is reduced because of the weather.   This means the hive has to live off the stored honey and pollen. A strong hive will survive off its own stores. A weaker hive may die. It’s important not to feed hives during the winter months. This stimulates the queen to lay more eggs and generate more forging bees. This hurts the hive during the nectar flow the next spring. If November bees are working to keep a hive going, there will be no nursing bees left in February to take care of the brood. The bees wear themselves out.   Their job changes from nursing to forging.

Bees can live up to 5 or 6 months when it’s slow and cool. During the summer months they can last as long as 6 weeks or so.   They wear out their wings and fall off. A lot of times you will see bees walking in front of the hive and not fly back. They can’t.

Thanks to the yearly honey bee migrations on semi-trucks; disease between the East and West coast has intermixed. At one time hives could be wintered without having to reduce their size. Now, hives have to be reduced during the winter because there not enough guard bees to keep out pests. Reducing the size of the hive helps a hive’s survival. This means removing a few supers that are empty. Take out the queen excluder. The metal wires pull away heat the bees need for keeping warm.

California Native Plants That Help Bees

When the weather starts to turn colder, there is less food for the bees to eat. One critical plant has helped bees survive the fall/winter passage. It’s Goldenrod. There are many different species of it. This is the often the last source for pollen for the year. Because of atmosphere carbon dioxide increase, the nutritional value of the pollen has drop over the past 100 years.

Atmospheric Carbon Dioxide accelerates the growth of pollen in Goldenrod, hence reducing the concentration of protean in pollen because of the quick growth. Bees need to gather more pollen to make up for the reduced protean.

Here is a link to the studies between CO2 and pollen nutrition for Goldenrod.

Study from Perdue University

Study from Yale

There are three California Native Goldenrods. All of them look like highway weeds. They bloom in late fall and are normally the last pollen sources for Honey and Native Bees.

They are perennials. You only have to buy them once. Plant them on a mound like a chaparral. They take over the yard. Great yellow bloom in fall.

Solidago altissima

Solidago lepida

Solidago canadensis

Bee Hive Condensation


As bees eat honey to keep warm, the byproduct is water (in the form of humidity) and carbon dioxide. In colder months water condenses on the inside of the outer walls of the beehive, not only the top. In a semi-weak hive, fungus and mold grow on the honey comb. This makes trouble for the bees.

Pictured right is water condensation from bees respiration and consumption of honey. It collects on the glass. In colder climates not like the Bay Area, condensation is not a problem. Since the climate here goes up and down with temperature during the winter, the condensed water evaporates and keeps the humidity high in a hive.

A way to collect the moisture is to use a feeder super and fill it with lavender, straw or anything that absorbs water. Let the moisture rise up to the top super and collect in the straw.

Pictured left is a beehive with a glass window on top of a feeding super. Bees drink the collected water off the straw. This moisture collection method has been used for a couple centuries. A Warre hive has a quilt made of burlap that does the same function. There is a small space at the top of the hive for adding straw or dry branches for water collection.

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