Pollen Baskets (Corbicula)

Common Eastern Bumble Bee - Bombus impatiens

(Photo:  Marvin Smith on 11/8/09)

Most everyone knows that bees visit flowers and collect nectar. Humans value the nectar product and call it honey. Bees also collect pollen. To the bee, pollen is as important as nectar. Pollen is the primary food for developing bee larvae.

Female bees (queens and workers) in family Apidae (honey bees, carpenter bees, bumblebees and several lesser known groups) have specialized structures called pollen baskets (corbicula) used for temporarily storing collected pollen so it can be transported back to the nest/colony. The pollen basket is a smooth, concave structure surrounded by long, stiff hairs located on the tibia of the bee's two rear legs. As the bee visits flowers, she accumulates pollen all over her body. She uses her legs to aggregate the pollen and transfer it to her pollen basket. It may look as if a bee simply has hairy legs, but some of those hairs (setae) are actually combs and brushes used for transferring pollen. The pollen is combed, pressed, compacted, and transferred to her pollen basket. Honey and/or nectar is used to moisten the dry pollen so it will stay in place.

Bumblebee with loaded pollen basket.

(Photo:  Beatriz Moisset via Wikimedia)

While most all bees collect pollen, not all bees have pollen baskets. Many have scopa, a general term referring to a number of different pollen-carrying modifications on the body of a bee. In most bees, the scopa is simply a particularly dense mass of elongated, often branched, hairs (or setae) on the hind leg.

Halictid bee, scopa loaded with pollen.

(Photo:  Beatriz Moisset via Wikimedia )

The bumblebee in the photo at the top of the page is a Common Eastern Bumble Bee (Bombus impatiens), probably the most often encountered bumble bee in eastern North America. It has an unusually long flight season and thrives across a wide range of habitats and climates ranging from the cold temperate zone (e.g., Minnesota) to the warm subtropics (south Florida). B. impatiens can be found in rural, suburban and urban environments. There are isolated pockets of Common Eastern Bumble Bees outside of it's normal range -- like California -- because it escapes from commercial greenhouses where it is used for pollination. The bee has no pollen because this photo was taken in early November when pollen sources were few and far between. She was lucky to find a few scraggly zinnias still blooming in our garden.

Sources and links:
Bombus impatiens on BugGuide
Pollen Basket on Wikipedia
Scopa on Wikipedia
Bumblebee legs on Bumblebee.org

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Pollen Baskets (Corbicula)

Woolly Bear Caterpillar Predicting the Weather in My World

Woolly Bear Caterpillar - Pyrrharctia isabella

(Photo:  Jo Smith on 11/14/09)

Folklore says: The longer the black ends on a Woolly Bear caterpillar, the longer and more severe the winter will be.

Entomologists say: The amount of black varies with the age of the caterpillar and the moisture levels in the area where it developed. Also, the length of the black ends can vary on caterpillars grown out together from the same group of eggs.

BugGuide makes a half-hearted defense of the Woolly Bear's powers of weather prediction by saying: The variability of the bands depends on many factors. As larvae mature, the reddish bands lengthen. Wetter weather lengthens the black bands. So while not a reliable measure, it makes some sense that onset of an early and thus longer winter will force younger and less red caterpillars into hibernation.

Woolly Bear caterpillars are the larval stage of Isabella Tiger Moths (Pyrrharctia isabella). They are common throughout almost all of North America. Larvae eat many plants and trees including grasses, asters, birches, clover, corn, elms, maples and sunflowers. There are usually two broods of P. isabella each summer. The first of two broods pupates in summer. The second brood overwinters as a caterpillar and pupates in spring. A photo of an adult Isabella Tiger Moth is here.

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Woolly Bear Caterpillar Predicting the Weather in My World

Flea Beetle - Kuschelina gibbitarsa

Flea Beetle - Kuschelina gibbitarsa

(Photo:  Marvin Smith on 11/14/09)

Flea Beetle General Description: Leaf-feeding beetles with a segment (femora) of the hind legs enlarged for jumping, which they will readily do when disturbed. Adult beetles chew small round or irregularly-shaped holes in plant leaves. Larvae typically feed on plant roots though some also feed on foliage. Many are serious agricultural pests, causing damage directly by plant feeding or indirectly by transmitting viruses. (Note: I suppose the flea beetle pictured here would actually be considered beneficial since it feeds on plants normally considered weeds.)

Species Identification: Typically four black spots on pronotum (short body segment between head and thorax) ... two spots toward the outer edges and two that blend together in the center ... iridescent green elytra (wing covers) ... approximately 5mm (1/4") long.

U. S. Range: Most of the eastern and central United States.

Host plants: Members of the mint family (Lamiaceae). Here in the Ozarks, I've found large populations of K. gibbitarsa on American Germander (Teucrium canadense).

Kuschelina gibbitarsa larvae on
American Germander leaf.

(Photo:  Marvin Smith on 6/25/08)

Comments: The beetle in the top photos was actually found while weeding a strawberry bed. Unfortunately, this bed was invaded by American Germander which we've been fighting for a couple of years. Like most members of the mint family, it is difficult to get rid of once established. K. gibbitarsa overwinter as adults. I'm sure this beetle was attempting to overwinter when we disturbed it with our weeding.

American Germander - Teucrium canadense

(Photo:  Marvin Smith on 6/24/08)

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Flea Beetle - Kuschelina gibbitarsa