Saturday, April 18, 2009

Blueberry Blossoms and Bumblebees - Subtitled She Works Hard for the Honey

Here a brief interuption in my travelogue of the Pacific Northwest announces the initial spring appearance of bumblebees in my yard. Now, I am fully aware that most people find this less than exciting, but perhaps, this can convince you to give the next spring bumblebee you encounter a second glance.

Spring bumblebees are the largest you will observe until late this next fall. They are the newly awakened hibernating queens, the only surviving members of the previous years colony. The task of creating a new colony falls entirely to this one bee.

Awakening is dependent on ground temperature and timing is crucial. The bee has minimal reserve and there must be blossoms available to fuel her and to allow her to gather resources to start the new colony. Start out too late and all the best nesting sites are taken.

Bumblebees prefer to nest in abandoned mouse homes. They are not able to dig their own holes, so competition for sites is fierce.

Bumblebees are the predominant pollinators of certain flowers, including blueberries, cranberries and certain types of clover. Tomato blossoms and chili peppers also respond well to the bumblebees unique ability to buzz pollinate or perform sonification. Bumblebees rapidly contract their flight muscles producing a high-pitched, intense buzz that is transmitted inside pollen containing hollow structures within the flowers. Like a living tuning fork, the bees discharge the pollen as an explosive cloud. This act both disperses pollen benefiting the plant and furnishes the bee with protein rich pollen. Plants that rely on buzz pollination produce little or no floral nectar, so honeybees do not visit regularly.

A bumblebee, though an insect, is by ingenious design essentially
warm-blooded. By “shivering” her massive flight muscles, she can create heat in her thorax.
Then, by contracting her muscles, she circulates the warmth into her abdomen. Bumblebee body
temperatures can vary between 40 and 104 F, regardless of the ambient temperature. Due to the bumblebee's ability to thermoregulate, she is able to fly and work at lower outdoor temperatures than honeybees. Bumblebees can start earlier in the day and stay out later in the afternoon.

As the owner of several blueberry bushes, I appreciate the services bumblebees provide, but I also just like watching them. Hopefully, you will now regard them with greater appreciation too.

(Thanks to the Flickr site for some of the bee photos)

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