- Author: Kathy Keatley Garvey
Dear Crab Spider,
Please don't eat the pollinators. You may help yourself to a mosquito, a crane fly, a lygus bug, an aphid, and a katydid, not necessarily in that order. And more than one if you like. In fact, how about an all-you-can-eat buffet of luscious lygus bugs? So good! Yes, you may tell all your arachnid friends about the nutritious, high-protein meals available just for the taking. Please do. Just don't eat the pollinators.
Sincerely Yours,
Pollinator Fan
Crab spiders do not listen. They will eat what they want and when they want it. And they will gorge themselves. They are not interested in joining Weight Watchers. They are Wait Watchers.
For the past several months, crab spiders have been lurking on our blanket flower (Gaillardia). Most of the time, they just sit there, waiting patiently for dinner to arrive. Sometimes it's a long wait--longer than it takes for a waiter to return to your table during a rush-hour holiday lunch.
So, Ms. or Mr. Crab Spider--not sure of the gender, but "Predator" will do--dined recently on a sweat bee, a female Halictus tripartitus. We watched Predator lunge at a honey bee (missed!) and pursue at a male long-horned bee, probably Melissodes agilis.
Our cunning little arachnid no doubt nailed a few others--the "waistline" is a dead giveaway.
- Author: Kathy Keatley Garvey
What's better than sighting a yellow-faced bumble bee, Bombus vosnesenskii?
Well, a newly emerged Bombus vosnesenskii queen.
On the last day of June, we spotted this fresh queen-looking foraging on our blanket flower (Gaillardia). Her jet-black color, sunny yellow markings, and untattered wings indicated that this was one of her first flights. Queen bees are huge--about 18 to 21mm long--much larger than the other bees in her colony. Workers (females) range from 8 to 17 mm while males measure between 10 and 15mm.
The queen took a liking to the blanket flower, buzzing from blossom to blossom and sharing communal meals--sweet nectar--with honey bees, longhorned bees, and carpenter bees. A camouflaged crab spider, sprawled out on the top of a blossom, itched to get in on the feeding action by snagging an inattentive bee, but the bees buzzed right past their would-be predator. Not today!
Bombus vosnesenskii is one of only 250 species in the genus Bombus, which is Latin for "buzzing." Native to the west coast of North America, Bombus vosnesenskii is considered the most abundant bumble bee from British Columbia to Baja California. Its importance to agriculture is crucial: it's commonly invited to pollinate commercial greenhouse tomatoes, which it does very well. The next time you eat a greenhouse tomato, you should probably thank Bombus vosnesenskii.
Want to learn more about bumble bees? Native pollinator specialist Robbin Thorp, distinguished emeritus professor of entomology at the University of California, Davis, is the co-author of the landmark Bumble Bees of North America: An Identification Guide (with co-authors Paul H. Williams, Leif L. Richardson and Sheila R. Colla), published by Princeton University Press. It's the winner of a 2015 Outstanding Reference Sources Award, Reference and User Services Association, American Library Association.
Want to hear a bumble bee buzz? Just click this link: Bumble Bees of North America: An Identification Guide.
It's almost like bee-ing there.
- Author: Kathy Keatley Garvey
A crab spider nailed a major pest, a lygus bug, Lygus hesperus. It's something you don't see very often. But you appreciate very much.
A lygus bug made the fatal mistake of feeding on a blanket flower (Gaillardia) where the cunning spider was lurking and waiting for prey...er...dinner.
A venomous bite and it was all over.
The lygus bug is easily distinguishable by its triangle or V shape on its back. The V does not stand for "Victory" when it's attacked and consumed by a crab spider.
Do not feel sorry for lygus bugs. Their piercing mouthparts suck the lifeblood (juices) right out of the plant tissues. You may have seen them feeding on berries, beets and beans. The females lay their eggs in the plant tissues. Their visible path of destruction ranges from discoloration and deformation to leaf-curling and lesions.
"Lygus bug adults are about 0.25 inch long and 0.1 inch (2.5 mm) wide, and flattened on the back," according to the UC Statewide Integrated Pest Management Program (UC IPM). "They vary in color from pale green to yellowish brown with reddish brown to black markings, and have a conspicuous triangle in the center of the back. Nymphs resemble adults, but are uniformly pale green with red-tipped antennae; larger nymphs have five black spots on the upper body surface. Nymphs do not have wings." (Read UC IPM Pest Management Guidelines for more information and how to control them.)
The some 200 host plants of lygus bugs include Russian thistle, wild radish, London rocket, black mustard and goosefoot.
Their enemies are many. "A parasitic wasp, Anaphes iole, which attacks lygus eggs, is available commercially and can be used for inoculative releases," UC IPM says. "It can reduce lygus populations in strawberry fields; but because thresholds for this pest are very low and adults moving into the field from external sources are not controlled, economically acceptable results may not be achieved. Naturally occurring predators that feed on the nymphal stages of lygus bug include bigeyed bugs (Geocoris spp.), damsel bugs (Nabis spp.), minute pirate bugs (Orius tristicolor), and several species of spiders."
Spiders? Yes, indeed.
- Author: Kathy Keatley Garvey
What a perfect match when a Gulf Fritillary butterfly touches down on a blanket flower.
They're both reddish-orange and showy.
Last weekend we spotted a Gulf Fritillary butterfly (Agraulis vanillae) land momentarily on a blanket flower (Gaillardia), in our bee garden.
The butterfly warmed itself, stretched its wings, and then fluttered off.
Thankfully, the Gulf Fritillary, thought to be extinct in the Sacramento-Davis area in the 1970s, is making a gigantic comeback, according to butterfly expert Art Shapiro, UC Davis distinguished professor of evolution and ecology. If you want it in your yard, plant passion flower (Passiflora), its host plant.
Then blanket a corner of your bee garden with the blanket flower (sunflower family, Asteraceae). The flower was probably named for the colorful patterned blankets made by native Americans.
Then the next time you see a Gulf Frit cuddle up with a blanket flower, grab your camera.
- Author: 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.