Posts Tagged: Robbin Thorp
A pond attracts dragonflies and damselflies.
Last weekend, though, we spotted a damselfly a good 65 feet away from our pond. It touched down on our passion flower vine (Passiflora). Lights, camera, action...
The enlarged photo revealed a surprise: a cluster of something reddish-orange beneath the thorax.
Now that's something you don't see every day!
"Water mites," said native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis. (There are also images on BugGuide.net.)
"Phoresy," said entomology graduate student Lesle Saul-Gershenz, and professor Sharon Lawler, both of the UC Davis Department of Entomology and Nematology. Phoresy is a symbiotic relationship in which one organism transports another organism of a different species. Bottom line: these bright red mites, from the tick family, are hitchhikers that feed on body fluids. They jump off when the host drops down over a new pond or wetland.
What's the effect of water mites on damselflies? Surely, that parasitic load of arachnid hitchhikers must be cumbersome.
Scientists Jose Andres and Adolfo Cordero of the Universidade de Vigo, Pontevedra, Spain, took a close look at parasitism in their research “Effect of Water Mites on the Damselfly, Ceriagrion tenellum,” published in a 2002 edition of Ecological Entomology.
They pointed out:
1. "Water mite parasitism is expected to have an important effect on damselfly survivorship and reproductive success, because mites drain considerable amounts of body fluids from their hosts," they wrote in their abstract. "This study tests the effect of water mite parasitism in a marked population of the damselfly Ceriagrion tenellum during 1995 (individuals marked as mature adults) and 1996 (individuals marked as tenerals)."
2. "Almost all teneral individuals were parasitized (98%) and mites were aggregated strongly on some individuals. Parasite load increased during the season."
3. "Parasites had no effect on the probability of recapture of hosts as mature adults. The average daily survival rate of lightly- and heavily-parasitized individuals, estimated with Jolly's stochastic method, did not differ significantly."
4. "In 1995 parasites had a significant effect on host mating success. The probability of mating was about 25% lower for heavily parasitized males than for lightly parasitized males. Lightly parasitized males also mated more times than heavily parasitized males, even if heavily parasitized males lived longer. In 1996, parasitism did not have an effect on male mating success. In both years mites had no effect on female lifetime mating success."
In conclusion, they found that "water mite parasitism does not reduce damselfly survivorship, but it could reduce male mating success in some circumstances. Further long-term studies are needed, especially in populations with a lower incidence of parasitism."
As for our little damselfly, it lumbered away with its distinctive load of little red hitchhikers clinging to its thorax...
Damselfly, with water mites attached, lands on the leaf of a passion flower vine. (Photo by Kathy Keatley Garvey)
When you visit the half-acre Häagen-Dazs Honey Bee Haven, a bee friendly garden on Bee Biology Road at the University of California, Davis, you might just see a cuckoo bee.
The cuckoo bee (see below) is a male Triepeolus concavus, as identified by native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis, who maintains an office in the adjacent Harry H. Laidlaw Jr. Honey Bee Research Facility.
Thorp has been monitoring the garden not only since it was planted--in the fall of 2009--but BEFORE it was planted, to collect the baseline data. To date, he's detected more than 80 species of bees, "and counting."
The cuckoo bee, nectaring on a blanket flower (Gaillardia), is just one of the species he's found in the garden.
The female cuckoo bee lays her eggs in the ground nests of other bees, including the sunflower bee, Svastra. Cuckoo bees are kleptoparasites, meaning that they steal the food stores provisioned by the host bee. Cuckoos lack pollen-collecting structures (scopa). So when the cuckoo bee eggs hatch, the larva will consume the pollen ball collected by the hosts, and kill and eat the host larvae.
Like human kleptomanias, they've found a way to make it in this world at the expense of others.
Thorp annually teaches at The Bee Course, described as a "workshop offered for conservation biologists, pollination ecologists and other biologists who want to gain greater knowledge of the systematics and biology of bees," and held at the Southwestern Research Station, Portal, Ariz. This year's dates are Aug. 25 to Sept. 4. The workshop attracts people from all over the world, including dozens from the UC system.
A male cuckoo bee, Triepeolus concavus, on a blanket flower (Gaillardia). (Photo by Kathy Keatley Garvey)
Male cuckoo bee sipping nectar. (Photo by Kathy Keatley Garvey)
We have long-horned cattle and long-horned grasshoppers. How about long-horned bees?
It's National Pollinator Week and what better time to run some photos of long-horned bees from the genus Melissodes?
These males (below) are probably Melissodes communis, according to native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis.
They were nectaring on salvia (sage) in a front yard in Davis, Calf., and keeping an eye out for the girls. The girls? They were dutifully carrying nectar and pollen back to their underground nests.
Melissodes belong to the family Anthrophoridae, described as a "very large family...found in all parts of the world," according to the book, Bees of the World, written by Christopher O'Toole and Anthony Raw. Melissa is Greek for "honey bee."
These long-horned bees are part of the tribe Eucerini, found all over the world except in Australia, according to O'Toole/Raw. Melissodes is a New World genera.
One thing's for sure: these ground nesting bees are fast-flying. In the blink of an eye, they're gone.
Male long-horned bee, genus Melissodes, probably Melissodes communis, as identified by Robbin Thorp. It is on salvia (sage). (Photo by Kathy Keatley Garvey)
Close-up of long-horned bee, a male Melissodes. (Photo by Kathy Keatley Garvey)
Up, up and away. Male Melissodes, long-horned bee, over salvia. (Photo by Kathy Keatley Garvey)
What's that hopping on our patio?
At first we thought it was a grasshopper. Not!
It was a katydid, sometimes called a "long-horned grasshopper," from the family Tettigoniidae (as identified by Lynn Kimsey, director of the Bohart Museum of Entomology and UC Davis professor of entomology, and native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis).
"Katydids have long, threadlike antennae," said Kimsey. "Grasshopper antennae are rarely much longer than the head."
Said Thorp: "Note the long slender antennae (as long as or longer than the body); the very long slender jumping hind legs; and the scimitar-like ovipositor at the end of the abdomen."
Scientists tell us that the number of described species in the family Tettigoniidae exceeds 6400. Most katydids are green. They're often perfectly camouflaged in bushes and trees.
A katydid. The name is derived from the "song" it sings by rubbing its wings together. "Katy did." "Katy didn't."
This katydid, a female, responded to our footsteps. (Their "ears" or hearing organs are on their front feet.)
It hopped away, but not before we captured its image.
A katydid, or "long-horned grasshopper," from family Tettigonliidae. (Photo by Kathy Keatley Garvey)
But there's one thing they don't do. They don't check out the sand dunes, home of the bee villages.
Tiny holes are everywhere, yet nobody seems to notice.
They're the work of digger bees, aka faux bumble bees. These are Anthophora bomboides stanfordiana, researched by native pollinator specialist Robbin Thorp, emeritus professor of entomology at UC Davis.
"The (female) bees suck up water nearby and then regurgitate on the (faces of the) sandstone cliffs to moisten and excavate soil for the tunnels, construct their turrets, and finally to seal the nest tunnel," Thorp says. The bees use some of the soil from the base of the turret to plug the entrance.
The bee turrets are somewhat like our gated communities! Keep out!
The digger bees have "grocery stores" all around them. You'll see the males and females foraging on the wildflowers, which include yellow and blue lupine, California golden poppies, wild radish, mustard, dandelions, and seaside daises.
If you crouch next to the bee villages, a nearby hiker is likely to ask "Lose something?"
No, we found something!
A female digger bee finishes her nest. (Photo by Kathy Keatley Garvey)
A digger bee scouts the landscape. (Photo by Kathy Keatley Garvey)
Flying low, flying fast. (Photo by Kathy Keatley Garvey)
Sandy cliffs of Bodega Head hold bee villages. (Photo by Kathy Keatley Garvey)