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The Honey Bees of Santa Cruz Island

[1993 Wenner, A.M. and R.W. Thorp. The honey bees of Santa Cruz Island. Bee Culture. 121 (5):272-275.]

The Honey Bees of Santa Cruz Island

Our familiar honey bee, not native to the United States, has been intentionally transported on a larger scale than might be true for any other animal or plant species (ably reviewed in 1989 by Walter Sheppard). During the colonial period, the dark European bee (“German” bee), Apis mellifera mellifera, was the primary bee of commerce (1500-1850). In fact, in Sheppard’s words, “Prior to the introduction of the Italian race…, A. m. mellifera was the sole race of honey bees present in the United States.”

The Virginia Colony was the first to import honey bees (in 1622); by 1654 honey bees had been established in New England. The frequent swarming habit of dark European bees, favored by beekeepers before moveable frame hives were available, resulted in their rapid spread throughout the eastern United States during the next 200 years.

Up to a century and a half ago, overland shipment of bees to California was considered impossible – travel through the Great Basin and deserts of the Southwest was too arduous. A botanist, Christopher A. Shelton, first breached that geographical barrier by bringing bees in by ship. An unknown beekeeper had transported 12 colonies down to Panama in early 1853 and sold them to Shelton, who at that time was introducing various plant species to California. Shelton managed to get the colonies to the Robert F. Stockton Ranch, just north of San Jose, California, but only one colony survived.

Other shipments followed, imported by John Harbison during the mid- 1850s. Harbison had abandoned gold mining to start the first nursery of fruit and ornamental trees in the Sacramento Valley but soon turned to beekeeping on a large scale. Known as the “Bee King of California,” he invented the comb honey section box still in use today and published The Beekeeper’s Directory. Soon honey bees were dispersed throughout California – before 1860 a thousand colonies were already present in San Jose.

In 1856 Southern California got its first bees from some of those original importations, and Ventura County – nearest point to the Northern Channel Islands off Santa Barbara – had its first commercial apiary in 1873. About that time an unknown beekeeper brought bees out to Santa Cruz Island but abandoned them well before 1880. Bees from that original introduction multiplied and spread over the entire island, with apparently no introductions since that time. The adjacent Northern Channel Islands had no such importations and have never had honeybees, but Santa Catalina Island in the southern group does have bees.

While dark European bees were being introduced into California, another development began in 1851, one that changed both beekeeping and the bee of commerce. Lorenzo Langstroth determined dimensions of the correct “bee space” and invented the first practical movable frame hive. Beekeepers began replacing dark European bees, noted for their excessive use of propolis and rather poor hivekeeping behavior, with Italian bees. In Ohio, Langstroth obtained his earliest shipment of Italian bees from Germany in 1863, but the first successful direct shipment of Italian bees had been into New York three years earlier.

Completion of the Transcontinental Railroad in 1869 permitted rapid transportation of bees from the East to the West with the first Italian colonies on record reaching Los Angeles, California in 1875. As in the East, California beekeepers gradually replaced dark European bees.

There are two sides to this coin, however. Whereas we can laud diligent beekeepers for their transportation of colonies nearly everywhere in the world, the degree to which those bees have affected various native bee species remains a question. During our visits to Santa Cruz Island and Santa Rosa Island (six miles to the west and an Island on which European bees have never existed), we noticed remarkable differences in insect visitation on flowering plants.

Nearly all insects visiting the more prominent Santa Cruz Island plants were honey bees, but a wide spectrum of bees, wasps, flies, and moths visited the same types of flowers on Santa Rosa Island.

A Satellite radar picture of Santa Cruz Island, illustrating the rough topography. Santa Rosa Island (6 miles away) is at the lower left.

A Satellite radar picture of Santa Cruz Island, illustrating the rough topography. Santa Rosa Island (6 miles away) is at the lower left.

Several years ago all five of the Northern Channel Islands were designated a U.S. National Park. Santa Barbara Island, Anacapa Island, and San Miguel Island were already administered by the Park Service at that time. Subsequently, Santa Rosa Island was purchased and placed under their control. Most of Santa Cruz Island remains an inholding of the National Park under ownership by The Nature Conservancy, with the Park Service continuing negotiations to obtain the remainder of the eastern tip of that island.

An opportunity arose. Since Santa Cruz Island is the only one of the five Islands that has ever had honeybees, is essentially uninhabited, and has well defined limits, we reasoned that it should be possible to locate and remove all honey bee colonies. Such an effort would provide us with at least one National Park where native bees would prevail and where a pre-European ecosystem could be studied, once native insects on that island had again achieved somewhat of a balance. Furthermore, with the apparently inevitable influx of Africanized bees into our local area, we could have a Southern California habitat free of that hostile intruder.

Accordingly, five years ago Robbin Thorp of the University of California, Davis, campus started a study of plant visitation to determine diversity and abundance of native bees and potential competition for pollen and nectar with honey bees while Adrian Wenner of the UC, Santa Barbara, campus searched for feral honey bee colonies. After two years of study, elimination of colonies from only the eastern half of the island began. This two-stage removal process would then permit studies of flower visitation and pollination on the eastern vs western halves of the island – as well as permit similar studies between Santa Cruz Island and honey bee-free Santa Rosa Island. Fortunately, our area has a Mediterranean climate, active foraging occurs all year, and studies can be conducted year-round.

A view from the top of Devil's Peak in the northern range, towards the south-southwest.

A view from the top of Devil's Peak in the northern range, towards the south-southwest.

Table 1

Table 1

Work on the project has been proceeding much on schedule, with the eastern half of the island largely free of feral bee colonies. More than 160 colonies have been located (see Table 1), of which about 130 have been removed. Laying queens have been recovered and provided to bee researchers and beekeepers so they can learn more about the characteristics of these bees after 110 years of isolation. Inspection of colony structure and behavior indicates that the island feral bees appear to be very similar to the dark European strain (except for color) and remarkably uniform over the entire island.

Records are also being kept of both colony location and cavity type (see table below). About two-thirds of the colonies found have been in cliff faces, either in discrete cavities, within rocky crevices, or under rock shelves. Other common sites are eroded cavities under the boles of scrub oak trees. Rarely are colonies found in the classic bee tree cavity, even though many such trees exist all over the island.

SANTA CRUZ ISLAND
COLONY, CAVITY, AND MORTALITY SUMMARY
10/92

A – COLONIES FOUND
Year Found East Half West Half Total
1988 14 13 27
1989 21 14 35
1990 20 8 28
1991 33 4 37
1992 32 5 37

Total

120 44 164
B – CAVITIES (Not Complete)
Cliff Hole 26 11 37
Rock Crevice 30 7 37
Rock Overhang 12 7 19
Clay Bank 5 3 8
Tree Trunk 23 11 34
Tree Bole 19 5 24

Total

115 44 159
C – MORTALITY
Natural 12 7 19
Other Dead 86 3 89
Likely Dead 26 0 26

Total

124 10 134

Dozens of the Schmidt-Thoenes bait hives have been installed at various points around the island. Catch frequencies by those hives permit a comparison with how well cavities formerly occupied by colonies will attract swarms (see table below) – to date, formerly occupied cavities seem more attractive.

YEARLY SWARM CAPTURE ON SANTA CRUZ ISLAND, A CALIFORNIA CHANNEL ISLAND WITH MEDITERRANEAN CLIMATE (ALL VALUES APPROXIMATE)
Year Survey Hives Swarms Former Colony Cavities Swarms Swarms in New Cavities Weather
1989 30 0 2 0 1 Drought
1990 54 0 13 0 0 Drought
1991 60 5 76 2 ? Wet March*
1992 68 9 92 15 4** Average
* The one major rain of the season came too late that year to produce buildup.

** Several times this number ended up in new cavities and are yet to be found.

To determine whether native bees have been forced to small refuges by the more dominant honey bees, we measure diversity and abundance of all bees at selected flower species as honey bees are being removed. Since honey bee removal began, the numerous species of native bees have been increasing in numbers rapidly and now outnumber honey bees at blossoms on much of the eastern half of the island (see figure).

The isolation and minimal human habitation of the 96-square-mile island since honey bees were introduced 110 years ago also permits an unparalleled opportunity for studies of natural colony distribution, foraging patterns of colonies, and competition between colonies. The pressure to find feral colonies quickly has also led to the first major changes in those techniques in hundreds of years (see Sources at end of article). Colony locations can now often be found within a few hours after finding bees at blossoms or at water – the record (held by Dan Meade of UCSB) is 24 minutes.

Other bee researchers have become involved in the project to varying degrees. From the Tucson USDA bee research Laboratory, Justin Schmidt and Steve Thoenes have furnished bait hives and pheromone lures for our use, while Gerry Loper has studied drone aggregation sites. Steve Buchmann from that laboratory has started an analysis of pollen grains to determine how far bees might range while foraging. Howell Daly from the UC Berkeley campus is conducting a measurement of wing patterns to determine which strain the Santa Cruz Island bees might belong to, while Rob Page of the UC Davis campus is conducting allozyme and DNA analysis toward that same end.

Dr. Wenner recently retired as Professor of Natural History at the University of CA, Santa Barbara but continues his honey bee research on Santa Cruz Island. Dr. Thorp is Professor of Entomology and Apiculturist at the University of CA, Davis.


The information for this article was obtained from several sources, most of which are listed here.

Caron, D.M. The Harbison California hive has a place in our beekeeping heritage. American Bee Journal 128:29-31. 1988.

Crane, E. The Archeology of Beekeeping. Cornell Univ. Press, Ithaca, NY. 1983.

Harbison, F.R. Flood Tides along the Allegheny. Massy Harbison Chapter, DAR (reprint), New Kensington, PA. 1941.

Mason, J.D. History of Santa Barbara and Ventura Counties, California. Howell North Books, Berkeley. 1883.

Root, A.I., E.R. Root, H.H. Root, and M.J. Deyell. The ABC and XYZ of Bee Culture. The A.I. Root Co., Medina, Ohio. 1947.

Ruttner, F., E. Milner, and J.E. Dews. The Dark European Honey Bee: Apis mellifera mellifera Linnaeus 1758. The British Isles Bee Breeders Association. 1989.

Schmidt, J.O. Swarms traps: An example of research and technology transfer. American Bee Journal 130: 333-334.

Schmidt, J.O. and S.C. Thoenes. The efficiency of swarm traps: What percent of swarms are captured and at what distance from the hive? American Bee Journal 130: 811-812. 1985.

Sheppard, W.S. A history of the introduction of honey bee races into the United States. American Bee Journal 129:617-619; 664-667. 1989.

Watkins, L.H. California’s first honey bees. Amer. Bee Journal 108:190-191. 1968.

Watkins, L.H. First honey bees in New England – 1638? Amencan Bee Journal 108: 19. 1968.

Watkins, L.H. On the transportation of honey bees to California, 1853-1861. American Bee Journal 109: 468-470.

Wenner. AM., D.E. Meade, and L.J. Friesen. Recruitment, search behavior, and flight ranges of honey bees. American Zoologist 31: 768-782. 1991.

Wenner, A.M., J.E. Alcock, and D.E. Meade. Efficient hunting of feral colonies. Bee Science 2: 64-70. 1992.