Category Archives: parasites

Twisted Parasites

Strepsipterans, or “twisted wing flies” (not really flies, I might add) are one of myriad creatures that prey on bees. The females grow between segments of the abdomen in a way that looks quite painful.
A "twisted" female living between the abdominal segments of a hapless wasp. Drawing by H T Fernald (1921) in Applied Entomology.
A “twisted” female living between the abdominal segments of a hapless wasp (drawing by H T Fernald (1921) in Applied Entomology). I really enjoyed this account that the CSIRO blog gives of Strepsiteran reproduction. I hope you do, too.

News @ CSIRO

By Kim Pullen – Australian National Insect Collection

Insects hide their enormous diversity well. We may hear that several thousand species live in and around our town or city, but where are they all?

They are in every patch of garden or vegetation. They are on nearly every bird or mammal that walks, runs or flies around us (think lice and ticks for example).

We don’t see a lot of them because most are small, some minute, and live hidden from our view. And if they are a rare species as well, then even entomologists (scientists that study insects) don’t get to see them much. The twisted-wing fly, which is actually not really a fly at all, is one such insect.

Strepsiptera is the taxonomic group these enigmatic creatures belong to, so we can also call them strepsipterans. That name is from the Greek, streptos meaning twisted, and pteron meaning…

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The Plight of the Bumble Bee Part IV: Pandora’s Bee Box

Nate Pope, Bee Biologist Extraordinaire

Illuminated by a single red light, Nate bent over the open cardboard box, alternately counting objects with a clicker and manipulating objects with gloved hands holding a long pair of tweezers. A swelling chorus of low buzzing made me more than a little nervous. Even though I knew that the  contents of the box couldn’t escape, I kept seeing phantom angry, swooping objects in the darkness.

In the above photo, Nate is removing pollen stores from a bee nest to see how much they ate this week (thus the gloves, long tweezers, and angry buzzing). Bees’ eyes are not designed to see red, so Nate works under red light to keep the bees from flying away when he opens the box.

From the title of the post, you’ve probably guessed what kind of bees Nate is studying.

Bombus impatiens colony. Please excuse the poor photo quality!

This is a domesticated colony of the Common Eastern Bumble Bee, Bombus impatiens. It is the most common bumble bee encountered on the east coast of North America from Ontario, Canada to Florida, USA.

By far the largest colony member, the queen perches protectively over a profusion of pots in which food (pollen and/or a thin watery honey) is stored, and larvae are raised. The queen is surrounded by smaller worker bumble bees. Bombus impatiens typically build underground nests.

Alternative Pollinators

(c) David Besa 2005

Despite their widespread use as agricultural pollinators, honey bees are often surprisingly bad at their jobs compared to native bees. Tomatoes, for example, require sonication, or buzz pollination. This involves producing large vibrations to shake pollen free from pollen-holding structures in the plant: something that bumble bees do quite well, but honey bees cannot. Farmers that grow tomatoes in greenhouses can therefore purchase colonies online, which are shipped via snail mail in cardboard boxes. The bumble bees are released in the greenhouse to pollinate their tomato plants to ensure a robust yield.

The Dark Side of Globalization: Tiny Smallpox Blankets

Most of us Americans have heard stories in school about the introduction of smallpox by European settlers the Americas. Although the European settlers had some natural resistance to the disease, the indigenous peoples of the Americas, who had never encountered the disease, had no immunity. The disease ran rampant in these communities, killing millions.

Parasitic mites, such as these tracheal mites infecting the air passages of a honeybee, can be spread from one bee to another similarly to pathology in humans.

In the past decade, bumble bees have also been in in decline in the Americas. Although there are multiple causes for these declines, including habitat destruction and agricultural pesticide use, diseases transported along with Bombus impatiens colonies used for greenhouse pollination are a major culprit. Many of these bees are raised in the Old World, where they pick up diseases such as tracheal mites (bugs that live in the bee equivalent of lungs) and transport them to the New World. New World bumble bees have not evolved defenses to these diseases because, like the indigenous peoples of the Americas, the bees have never been exposed to them before. Tragically, once these diseases get out of the bee box, it is almost impossible to reverse their spread through native bee populations.

Bombus franklini, photo courtesy of Robbin Thorp. Click the picture to view the Red List Profile.

One of the casualties of the bees-in-a-box is Bombus franklini, a species discovered by UC Davis Professor Emeritus Robbin Thorp. Thorp’s research showed that from 1998-2006, sightings of B. franklini decreased drastically. Only one bee was sighted in 2006, and as far as I know, there have been no more sightings of Franklin’s bumble bee since.

For more information on how to help our sisters the bumble bees, please check out the Xerces Society’s Bumble Bee Conservation Initiative.