Saturday, November 28, 2009

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


Monday, November 23, 2009

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.


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)


Sunday, November 22, 2009

Hawaiian Beet Webworm Moth - Spoladea recurvalis

Hawaiian Beet Webworm Moth
(Photo:  Marvin Smith on 11/8/09)

Identification: Brown with two incomplete white stripes on each forewing, and a complete white stripe across each hindwing ... wingspan 19-21 mm (around 3/4")

Range: The common name "Hawaiian Beet Webworm Moth" sounds exotic and specialized. In fact, it is neither. In North America S. recurvalis is found from Ontario and New York south to Florida and west to California. Worldwide distribution includes most warmer regions in Australia, Africa and southeast Asia -- and, yes, Hawaii. 

Host plants: Larvae feed on beets, chard, spinach and a wide variety of related weeds in genera Chenopodium and Amaranthus. In Africa, Spinach Moth is the common name for this moth.

Hawaiian Beet Webworm Caterpillar
(Photo:  Alton N. Sparks, Jr., University of Georgia,

Sources and links:
Spoladea recurvalis on BugGuide
Flora of Zimbabwe
Chenopodium on Wikipedia
Amaranthus on Wikipedia


Thursday, November 19, 2009

SkyWatch Friday: In The Pink

A Hazy Sunrise
(Photo:  Jo Smith on 10/21/09)

The day turned out nice despite the haze persisting throughout.


Wednesday, November 18, 2009

Nature Notes: Baldfaced Hornet - Dolichovespula maculata

Baldfaced Hornet - Dolichovespula maculata
(Photo:  Marvin Smith on 10/25/09)

IDENTIFICATION: Black with white markings on the head, thorax, and the last few segments of the abdomen ... wings smoky ... like other Vespidae, wings are folded lengthwise when at rest ... males and worker females are around 5/8" long ... queens are larger.

LIFE CYCLE: A fertilized female (queen) overwinters, then begins a new nest in the spring. She lays eggs that develop into non-fertile female workers. Once these workers become adults, the queen only lays eggs which the workers tend and feed. Several generations of workers are produced. Late in the summer or in early fall, the queen lays eggs that develop into males and fertile females. As winter approaches, all the hornets except for mated females die. The mated females overwinter in protected habitats such as cracks and crevices. They become the next season's queens and begin the process again. In the deep south it is possible for the hornets to remain active all year.

NESTS: Hornets construct large, inverted pear-shaped paper nests that are usually attached to tree limbs. Small branches may be included in the nests to give extra support. The grayish brown nest has two to four horizontally arranged combs and an entrance hole at the bottom. Workers chew weathered wood and old boards to create the "paper" for the nest. This is the reason for hornets' large, powerful jaws.

(For photos of a hornets' nest -- and a humorous tale about its procurement -- check out MObugs.)

FOOD: Adults are commonly found on flowers where they drink nectar. They will also feed on fallen, over-ripe fruit. Workers feed developing larvae a sugary solution they produce and also pre-chewed insect bits. Larvae also feed adults a sweetish secretion from their mouths.


Monday, November 16, 2009

My World Is Foggy

Morning Fog by Jo.
(Photo:  Jo Smith on 11/11/09)

My World is foggy
-- sometimes.

I don't know if meteorologists make a distinction between fog and being enclosed by clouds. The effect is the same. Up here on a ridge in the Ozark Mountains were are sometimes up in the clouds. As you drive down into Bear Creek Valley, the fog/cloud dissipates. Driving along the valley floor you are free of fog with a low, overcast sky overhead.


Sunday, November 15, 2009

Differential Grasshopper - Melanoplus differentialis - Female

Differential Grasshopper - Melanoplus differentialis - Female
(Photo:  Marvin Smith on 10/8/09)

IDENTIFICATION: General color is yellow to yellowish-brown with contrasting black markings ... wings are colorless ... black herringbone markings on outer face of hind femora ... hind tibiae are yellow with black spines and a narrow black ring near the knee ... average length for males is around 1 1/4" ... females are larger, averaging around 1 3/4".

RANGE: One of the more common grasshoppers. Can be found throughout most of the U. S.

FOOD: A mixed feeder that prefers grasses, especially lush vegetation in moist crop area (i. e. corn, clover, alfalfa and various garden crops). Although M. differentialis can be a serious pest in cultivated crops, it's usually not a problem in grasslands.

SEASON: Adults are common in the latter part of July. They deposit eggs from mid-August to October, and the eggs overwinter.

OVIPOSITON: Eggs are [normally] deposited in raised plant crowns of somewhat isolated clumps of sod. Common oviposition sites are compact roads, deserted fields, edges of weed patches and well-grazed areas near weedy ravines. Why the female pictured above chose to oviposit in a nail hole on our porch steps, I do not know. It was not a good choice.

Sources and links:
BugGuide Species Page
Grasshoppers of Colorado


Friday, November 13, 2009

Melonworm Moth - Diaphania hyalinata

Melonworm Moth - Diaphania hyalinata
(Photo:  Marvin Smith on 11/2/09)

Identification: Very distinctive white to translucent wings with dark brown border ... a tuft of bushy hairlike scales at the tip of the abdomen ... wingspan 2.5-3 cm (around an inch).

Range: Permanent range is Central and South America, the Caribbean, and southern Florida (and maybe South Texas). Moths disperse northward in the eastern U. S. during the summer and have been recorded in New England and the Great Lakes region.

Life cycle: Egg, five instars, pupae and adult. Under optimal conditions, Melonworm Moths can complete a full life cycle in 30 days.

Host plants: Melonworm caterpillars feed on cucurbits. Summer and winter squash are preferred. Cucumber, gerkin, cantaloupe and some pumpkins are secondary choices. Larvae feed mainly on foliage, but may feed on the surface of the fruit, or even burrow into the fruit after eating all the leaves. Crop yield losses to D. hyalinata can be significant.

Comments: The University of Florida says moths are not attracted to light traps, but the moth I photographed was under our porch light.

I found mentions of the "tail feathers" as aids in dispersing pheromones. I believe this is correct, but could not confirm from a reliable source.

Melonworm caterpillar
(Photo:  Alton N. Sparks, Jr., University of Georgia via Forestry Images)

The two white stripes on the Melonworm caterpillar are distinctive, but may be faint in early instars and are lost in the final instar.

Sources and Links:
Forestry Images
BugGuide Species Page
University of Florida


Wednesday, November 11, 2009

Nature Notes: Pipevine Swallowtail (Battus philenor)

Female Pipevine Swallowtail  (Photo: Marvin Smith on 11/03/09)

In the East and California, Pipevine Swallowtails (Battus philenor) are seen mainly in the spring and summer. However, here here in the South they are more common in late summer and fall. In Mexico they fly year round.

Adult B. philenor nectar from a wide variety of flowers and are usually found in open fields or open spaces bordering woodlands. The female in the photo above was nectaring from the zinnias that brighten our vegetable garden.

Male Pipevine Swallowtail Butterfly
(Photo: Sturgis McKeever, Georgia Southern University,

The inner hindwings on male Pipevine Swallowtails are more iridescent than those on females. B. philenor mimics several other butterflies including Eastern Tiger Swallowtail (female, dark phase), Black Swallowtail (female), Spicebush Swallowtail, Red-spotted Purple and Diana Fritillary. BugGuide provides comparison images that help differentiate between these butterflies.

Pipevine Swallowtail caterpillar
(Photo: Sturgis McKeever, Georgia Southern University,

Larvae/caterpillars feed on Aristolochia species. Larvae presumably take up toxic secondary compounds from their hostplant. Both larvae and adults are believed toxic to vertebrate predators, and both have aposematic (warning) coloration. (BugGuide)

Pipevine Swallowtail chrysalis
(Photo: Sturgis McKeever, Georgia Southern University,

In temperate regions, Pipevine Swallowtails overwinter as pupae (in a chrysalis). In mid-season, the butterfly spends about two weeks in this pupal stage.


Monday, November 09, 2009

A Cloudless Sulphur Butterfly (Phoebis sennae) in My World

This tattered and worn Cloudless Sulphur Butterfly on a tattered and worn zinnia flower seems an appropriate symbol for current conditions in my world. Nature is winding down for winter.

We've only had a couple of light frosts thus far, but soon a major blast of Arctic air will come barreling down from the north and all the bugs and flowers will be gone. Or will they?

While I won't see nearly as many insects until spring, they will still be here. Most will be hiding in leaf litter or underground in their larval forms. A few  will overwinter as adults and surprise me with their appearance on warm winter days. All will be waiting for spring to begin again their life cycles.

In their own way, the zinnias will also still be here. All the genetic information needed to produce new plants and flowers is stored in their tiny seeds. Were we good gardeners, we'd deadhead each flower after the bloom is spent. Were we even mediocre gardeners, we clean up all the old plants after they freeze. But if history is any guide, the dead zinnias will remain in the garden for most of the winter if not all the way into next spring. Our excuse is that the zinnias need plenty of time to reseed themselves. Also, many times I've seen Goldfinches feeding on zinnia seeds. Regardless, the zinnias are still here.

Nature will soon take a winter's rest, but insects and flowers still abound and are just waiting for spring to begin again.


Sunday, November 08, 2009

Nature Notes: Butterfly weed (Asclepias tuberosa)

Butterfly Weed is a native herbaceous perennial. Though it is a member of the milkweed family it does not have milky-sapped stems.

Butterfly weed is easily grown in average, dry to medium, well-drained soils in full sun. Drought tolerant. Does well in poor, dry soils. New growth tends to emerge late in the spring. Plants are easily grown from seed, but are somewhat slow to establish and may take 2-3 years to produce flowers. Mature plants may freely self-seed in the landscape if seed pods are not removed prior to splitting open. Butterfly weed does not transplant well due to its deep taproot, and is probably best left undisturbed once established.

Butterfly Weed has a long bloom period from late spring throughout the summer. Flowers are a nectar source for many butterflies and leaves are a food source for monarch butterfly larvae (caterpillars).

Great Spangled Fritillary butterflies are among the species attracted to Butterfly Weed by its color and its copious production of nectar.

We hope the Butterfly Weed's wind-borne seeds have a successful journey and establish many more plants for future years.

All photos are by Jo.