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Bee Breeding in the Field: Part 1

The Way Back to Biological Beekeeping, Part 16

American Mite History Background

QUARTERLY REPORTS

Bee Culture Research Investigations
Madison, Wisconsin
Period: Jan 1 – Mar 31, 1960 ENT c10-1(C)
Biology of diseases and pests of honey bees and development of control methods.
Mite Survey – Late March.
A sample of 25 live bees from each of 50 colonies was shaken in about 15 cc. of 1:10,000 Triton X-100 solution in a shell vial. About 10 cc. were pipetted from the bottom and examined in a petri plate at 20X. Mites were observed in 40 of the 50 samples. When the 10 colonies from which no mites had been found on the first sampling were resampled, 9 had mites. The colony that exhibited no mites on the first two samples had mites on the third sampling. As many as 10 adult mites were found in one sample, although 47 of the samples had 4 or less. It is evident that external mites, Acarapis sp. infest all or almost all the colonies at the Madison laboratory. A sample was sent to Beltsville for identification – reported spade shape coxal plates. Live bees were sent for studies on focal point of infestation and further study for species identity.

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Bee Culture Research Investigations
Madison, Wisconsin
Period: Apr 1 – Jun 30, 1960 with Quarterly Progress Report now labeled Administratively Confidential. ENT c10-1(C)
Biology of diseases and pests of honey bees and development of control methods.
Mite Infestation. (Acarapis spp.)
Fifty colonies were sampled during late March and five during early May. A sample of 25 live bees from each colony was shaken in about 15 cc’s of 1:10000 Triton X-100 solution in a shell vial. About 10 cc’s were pipetted from the bottom and examined in a petri plate at 20X. As shown in table 1, mites were observed in 40 of the 50 samples taken in late March. When the 10 colonies from which no mites were found on, the first sampling were resampled, 9 had mites. The colony that exhibited no mites on the first two samplings had mites on the third sampling. As many as 10 adult mites were found in one sample, although 47 of the samples had 4 or less. The 5 colonies sampled in early May all had mites, although 3 was the maximum number of adults found in a sample. It is evident that external mites Acarapis spp. infest all or almost all of the colonies at the Madison laboratory. A sample was sent to Beltsville for focal point of attack and identification. External mites were found in all samples having the truncated coxal plate. They were found on the wing bases, a position usually associated with Acarapis Vagans. The most common external mite thus far found has been A. dorsalis, showing a deep cleft in the coxal plate. This mite is usually located in the scutellar groove. Colonies will be sampled again during August to determine the incidence of infestation at that time.

ABSTRACT: A 1959 report that bees from California infested with Acarapis woodi had been intercepted in California, which was later proved to be in error, has stimulated an intensive search for the acarine disease causing mite and other mites. An external mite tentatively identified as A. vagans has been found infesting bees of all colonies (50) examined at the Madison laboratory. This mite has been reported from a few other locations but appears to be less common than A. dorsalis. Separation of species is based on point of infestation and shape of the mite’s posterior coxal plate.

Progress Report Under Cooperative Agreement # 12-14-100-2362(33) between University of Wisconsin Agricultural Experiment Station and Entomology Research Division, ARS, USDA
Period: Oct 1, 1959 – Jun 30, 1960
These studies are concerned with: #9. Evaluation of the incidence of external mite (Acarapis spp.) infestation of bees in the University colonies. ABSTRACT: A 1959 report that bees from California infested with Acarapis woodi had been intercepted in California, which was later proved to be in error, has stimulated an intensive search for the acarine disease causing mite and other mites. An external mite tentatively identified as A. vagans has been found infesting bees of all colonies (50) examined at the Madison laboratory. This mite has been reported from a few other locations but appears to be less common than A. dorsalis. Separation of species is based on point of infestation and shape of the mite’s posterior coxal plate.

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Bee Culture Research Investigations
Laramie, Wyo.
Period: Jan 1 – Mar 31, 1961 with Quarterly Progress Report labeled Administratively Confidential.
Work Project ENT c10, Line Project Ent c10-1
Biology of diseases and pests of honey bees and development of control methods, #3. External mites on honey bees, Table 7 External Mites on honey bees at Laramie Page 10, Table 8 Sexes or developmental stages of Acarapis dorsalis mites found at Laramie Page 11.

ABSTRACT:
Page #1, Acarapis dorsalis mites were found on about 3% of all sample bees examined, from our Laramie colonies in February and March. At least 58% of our colonies and all of our apiaries have these external mites. Eggs, larvae, and both male and female adults were found in the dorsal scutellar groove of the thorax of the honey bee. Their identity was also confirmed from cleared microscopic mounts of adult females, which disclosed the deeply cleft hind coxal plate characteristic of this species. All the same bees were examined for neck mites: A. externus, also, but none was found. This appears to be the first record of external mites on honey bees in Wyoming, but Mr. Revell’s notes indicate some were seen at this laboratory in 1944, and by Dr. Burnside at Beltsville, Maryland in 1941. Also, he recalls seeing some at Ames, Iowa in 1917 from honey bees.

3. External mites on honey bees. Page #9, Acarine mites have been found in the dorsal scutellar groove on the thorax of adult worker honey bees from many of our colonies here in Laramie. A few of the adult female mites have been mounted in a polyvinyl alcohol + lactic acid + phenol mounting medium, and a few have been mounted in Hoyer’s solution. These media clear at least some of the specimens satisfactorily so as to disclose the coxal plate. In our specimens this is deeply cleft, characteristic of Acarapis dorsalis. Morgenthaler (1934), as recently determined by E. W. Baker of the U.S. National Museum (See Beltsville 4th Qtly. Rpt. 1959: pp. 7-7b). This appears to be their first record in Wyoming (But see below). This breeding place of external mites was first discovered in England by Morison (1931) Bee World 12(4): 40-42 (April) and 12(10): 110-111 (Oct)

Table 7 summarizes a survey made of all our colonies in February and again in March, 1961, for external mites, both in the scutellar groove and in the ventral neck region. No mites were found in the latter region which is the typical breeding place of A externus Morgenthaler (1927), originally observed there by Homann in Germany (1933): Zeitschr. f. Parasitenk 6(3): 350-415. It may be noted that about 3% of all bees examined were found infested with the dorsal back mite, A. dorsalis. A surprising 58% of our colonies were infested with this mite, and since most samples obtained in February contained not more than 20 bees per colony, and in March not more than 30 bees per colony, it is probable that even a larger percentage of our colonies are infested. All six of our apiaries are infested with this external mite.

Page #12, Table 8 summarizes the sexes and developmental stages of Acarapis dorsalis found during the above survey. It may be noted that eggs, larvae, and both male and female adults were found. Eggs were most abundant, and bees infested with eggs only were found more frequently than bees infested with any other stage or combination of stages. Two mite eggs on one bee were common. Three of the four adult male mites found were with an adult female on the same bee. All mites were found by examining individual bees under a dissecting microscope. They were then transferred with a teasing needle to a drop of glycerine on a microscope slide, and their identity confirmed under a binocular microscope at a magnification of 150X. It is surprising that the eggs are nearly as large as the adults.

A few measurements showed the eggs averaged about 130 x 65 microns. Morgenthaler (1932) Zeitschr. f. angew. Ent. 19(3): 449-489, found adult female A woodi (Rennie) (1921), mites varied 106-180 x 65-85 microns, and external mites are indistinguishable by size from it. The eggs are a shiny white, and show up more distinctly than the slightly yellowish adults. The eggs adhere firmly to the tiny branched hairs in the scutellar groove of the bee, and in removing the eggs one nearly always breaks off the tips of these bee hairs also. The larvae cling to these hairs tenaciously, so that one usually finds tiny branched hairs next to the larvae also. The reliability of any washing technique for discovering external mites on honey bees needs further investigation. A survey of 3900 bees from 48 Italian and 12 Caucasian colonies in Laramie was made in February and March 1950, using Morgenthaler,s method of washing 50 or 100 bees in Oudeman’s fluid, filtering the supernatant through filter paper, and examining the sediment left on the paper for external mites under a microscope. No external mites were found then (Laramie’s 1st Qtly. Rpt. 1950:17-18).

Similarly, no mites were found in 1000 sample bees from 10 Laramie colonies examined by a mass washing technique at Beltsville in May 1959 (Beltsville 2nd Qtly. Rpt. 1959: p. 6). It seems doubtful that any washing technique would wash off any mite eggs which adhere so firmly to the branched hairs of the bees, unless it were allowed to act a long time and was capable of dissolving the adhesive material. Dr. J. E. Eckert of Davis, California, made the verbal statement at the January 1961 Omaha meetings of the American Beekeeping Federation, that the “neck” mite, Acarapis externus, is found in a very “sticky secretion” in the ventral neck region of the bee. Therefore, even the adults of this species probably would be difficult to wash off their host. Dr. Eckert stated that the few mites he had found on the wings or on the fore part of the abdomen of honey bees had this same sticky secretion, so that he suspects that the so-called A. vagans Schneider (1941) reported from these breeding sites may simply be A. externus colonies resulting from a gravid female having to start egg-laying in these other locations before she was able to migrate to the neck region. Any washing technique also has the disadvantage of requiring identification by microscopic examination of cleared specimens of adult females in order to identify the species, or determine its probable breeding place. The wings and fore-abdomen were first found to be breeding places of external mites by Orosi-Pal in Hungary: Zeitschr. f. Parasitenk. 7(2): 233-267 (1934), and: Deutsch. Inkerfuh. 9(12): 398-400 (1935). Males and immature stages of these four Acarapis species cannot be differentiated morphologically. Morgenthaler (1928, 1932, and 1934) had found biometrical averages of the adult female only could be used to distinguish A. externus by its long hind tarsal segments, and A woodi by the shorter distance between the inner margins of its spiracles.

Page #13, We can find no mention, even in Laramie’s Quarterly Reports, of external mites having been found on honey bees in Laramie or Wyoming before. However, Mr. Irven Revell has kept some typewritten notes he made which show that some external mites were found at this laboratory in December 1944. Samples of 50 bees per colony collected from our Collegian Dairy apiary on Dec. 8, 1944, were examined by brushing the top of the head and thorax and the underside of the wings of individual bees with a fine brush while being held over a smooth bond paper, and inspecting the debris falling on the paper, under high-dry magnification (645x) of a binocular microscope.

Eggs and adults were also seen on individual bees (under a dissecting microscope?) by Dr. Burnside and Dr. Sturtevant, but their location on the bee was not recorded. Four of the twelve colonies at this apiary were found to have external mites. About 3% of the bees examined were infested at that time. Burnside and Revell also found external mites on bees of three of the nine colonies at the Fish Hatchery apiary, examined December 16, 1944. As one mite was found under a mandible and others were found on the underside of the wings close to the base, it seems probable that these were not A. dorslalis, but probably were one of the other external species. It is not recorded how many bees from this apiary were examined for external mites, but 34 to 50 live bees per colony were examined for Nosema at the same time, so it is presumed that these same bees were examined for mites also.

Since package bees were purchased annually at Laramie, it was supposed by them that these external mites were imported with package bees from the South. Mr. Revell,s notes also state that Dr. Burnside had found similar external mites on honey bees at Beltsville “in the fall of 1941.” Apparently this was not recorded in the Beltsville Quarterly Reports. This seems surprising, since external mites on honey bees in the United States had never previously been recorded by American investigators. Morgenthaler in Switzerland first reported finding external mites on honey bees from North America (Canada) in 1926: Schweiz. Bienenztg. 49(5): 220-224. Brugger in Switzerland first reported finding external mites on honey bees from the United States in 1930 (in a sample from Geneva, New York: Arch. f. Bienenkunde 17(4/5): 113-142 (1936).

In August 1959 Australian authorities notified the California State Apiary Inspector that California bees shipped to Australia had been found infested with Acarapis woodi mites. As this is the internal species that infects the thoracic tracheae of honey bees, causing Acarine disease, which is common in Europe, has never been known in North America, this caused a serious scare. Fortunately, the mites proved to be the external species (or subspecies): Foote, H. L. Amer. Bee Jour. 99(10):415 (Oct 1959); Anonymous, Amer. Bee Jour. 99(12): 490 (Dec. 1959). A dorsalis has since been found on other California bees: Harper, R. W. Coop. Econ. Insect Rpt. 9(44): 968 (Oct. 30, 1959). A. externus also has been found here: Eckert, J.E. and Shaw, F.R. (1960) “Beekeeping”: p. 375., Macmillan, N.Y.

Surveys of bees from many states by A.S. Michael at Maryland have shown external mites present in most of the southern states and in several other scattered states also (Beltsville 3rd Quarterly Report for 1959 and subsequent Reports) e. g. from: Louisiana, California, Utah, Maryland, Florida, Georgia, West Virginia, Mississippi, and Tennessee.

Page #14, Incidentally, Dr Echert found A. dorsalis mites on Nebraska bees, during his demonstration of examining individual bees for mites, at the Omaha (1961) beekeepers, meeting. Therefore states adjacent to Wyoming, both on the east and west, also have external mites on honey bees. One of our Campus colonies previously found infested with Acarapis dorsalis mites was moved on February 23, 1961 into a greenhouse to pollinate some special alfalfa plants of the Wyoming Agricultural Experiment Station agronomists. In order to determine whether the warm greenhouse temperature influenced the external mites on the bees of this colony, samples of 100 bees each were examined on three subsequent dates: Feb. 28, March 13, and March 24, or 5, 18, and 29 days after moving the colony, respectively. Mite eggs only were found on 3% of the bees examined February 28th; no mites of any stage were found at the two later inspections.

Mr. Revell states that in the spring of 1917 when he was a student at Ames, Iowa, his zoology professor demonstrated the method of brushing bees, bodies to look for external mites, and that some microscopic mites were found on honey bees then. This precedes the European investigation of external mites, such as those of Morgenthaler and his associates in Switzerland, and even the British investigations of Rennie and his associates on the internal Acarapis woodi of honey bees, both in the early 1920′s. We wonder if such early records of finding external mites on honey bees in the United States were ever published. Manuscript published: Hitchcock, J.D. A bee mite (Acarapis dorsalis) — Wyoming. Coop. Econ. Insect Report 11(11): 157 (3/17/61).

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Bee Culture Investigations, Laramie, Wyo.
Period: Apr 1 – Jun 30, 1961 with Quarterly Progress Report labeled Administratively Confidential.
Work Project ENT c10, Line Project ENT c10-1: Biology of diseases and pests of honey bees and development of control methods, 4. External mites, Table 4. External Mites Found on Individual Bees at Laramie, Wyo. : 2nd Quarter 1961, Page 9; Table 5. Numbers of Bees Infested with Different Stages of External Mites, Page 10.

ABSTRACT:
Page #1, Acarapis dorsalis mites were found in the dorsal groove on the thorax of about 3% of the bees and in about 60% of the colonies over wintered at Laramie. Acarapis dorsalis mites were found on about 8% of the bees in 100% of packages received from Louisiana. The same bees were infested with Acarapis vagans on their wings. About 2% of the bees and 40% of the packages were infested with these wing mites. Thoracic mites were also present on about 7% of the bees in 68% of packages received from Georgia. The same bees were infested in their neck region with Acarapis externus. about 1% of the bees and 20% of the packages were infested with neck mites.

Page #6, 4. External Mites., The first observation of external mites on honey bees in Wyoming was reported in the Laramie 1st Quarterly Report for 1961: pages 9-14, including Tables 7 and 8. These were the “Back” mites: Acarapis dorsalis, living in the dorsal scutellar groove on the thorax of the bee. About 60% of the colonies, and about 3% of the bees sampled were found infested. Our bees were also examined for “Neck” mites: Acarapis externus, known to live in the neck region of the bee, but none were found.

Page #8, Another sampling of bees from all our apiaries was made in April, 1961, for the dorsal “Back” mites only. Results are summarized in Table 4. All apiaries were infested, showing 20 to 60% of the colonies in different apiaries infested: average 44% of all colonies. From 1.1 to 4.7% of the bees sampled from different apiaries were infested: average 2.9%. This is about the same percentage of bees infested as during the previous two months. Among package bees received from Mitchell’s apiaries of Bunkie, Louisiana, sampled in May, we observed both “Back” and “Wing” mites: Acarapis dorsalis and Acarapis vagans: see Table 4.

The “Wing” mites occurred both on the upper side of the hind wings and the lower side of the front wings. Three individual bees were found infested with both “Back” and “Wing” mites. “Back” mites were found on 8.4% of the bees and in 100% of the packages. “Wing” mites were found on 2.1% of the bees and in 40% of the packages. these bees were examined for “Neck” mites also, but none were found. Among package bees received from Rossman’s apiaries of Moultrie, Georgia, sampled in June, we observed both “Back” and “Neck” mites: Acarapis dorsalis and Acarapis externus: see Table 4. “Back” mites were found on 7.2% of the bees and in 68% of the packages. “Neck” mites were found on 1.4% of the bees and in 20% of the packages. Once an individual bee was found infested with both “Back” and “Neck” mites. These bees were examined for “Wing” mites also, but none were found.

The “Back” mites observed on Louisiana package bees included 64 eggs on 37 bees, 42 immature stages on 34 bees, 26 adult females on 25 bees, and 6 adult males on 6 bees. The “Back” mites observed on Georgia package bees included 45 eggs on 23 bees, 22 immature stages on 16 bees, 24 adult females on 20 bees, and 3 adult males on 3 bees. As many as 5 eggs were found in the dorsal groove of a single bee. As many as 4 immature stages were found in the dorsal groove of a single bee. As many a 3 female mites were found on a single bee. Of the 9 males observed in the dorsal groove of both groups of package bees, 6 occurred on bees found to have a female mite in the dorsal groove also.

The “Wing” mites observed on Louisiana package bees included 30 eggs on 16 bees, 9 immature stages on 5 bees, and 3 adult females on 3 bees. As many as 3 eggs or 3 immature stages were found on the wings of a single bee. Of the 19 infested bees, 8 had mites on both the front and hind wing (on the same side), 7 bees had only a hind wing infested, and 4 had only a front wing infested. “Wing” mites were found on the right wings of 12 bees and on the left wings of 7 bees. The “Neck” mites observed on Georgia package bees included 12 eggs on 5 bees, 12 immature stages on 6 bees, 4 adult females on 4 bees, and 1 adult male on 1 bee. As many as 3 eggs, or 3 immature stages were found on a single bee. Table 5 summarizes the numbers of bees infested with different stages of these external mites: eggs, immature, and adults. Most individual bees, 68%, were infested with only a single stage of external mites. These included eggs only: 28%, immature stages only: 25%, and adult mites only: 15%, of the infested bees. however, 30% of the infested bees were infested with two stages of mites, and 2% of the infested bees were infested with all three stages of the mites.

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Bee Disease Investigations, Laramie, Wyo.
Period: Oct 1 – Dec 31, 1961 with Quarterly Progress Report labeled Administratively Confidential.
Work Project ENT c10, Line Project ENT c10-1: Biology of diseases and pests of honey bees and development of control methods, 4. Esternal Acarapis mites, Table 2., Survey of external mites on adult worker honey bees at Laramie: December 1961: Summary, pages 4-5. Page #4, 4. External Acarapis mites. A survey was made of sample bees from all our colonies for external mites. Usually 30 bees were examined from each colony. The back (dorsal groove and adjacent areas of the thorax), underside of the neck, and the wing bases–both right and left sides, of each bee were examined with a dissecting microscope for the presence of external mites, in various stages of development.

Results are summarized, by apiaries, in Table 2. All apiaries were infested; on the average, 46% of the colonies, and 1.6% of the bees sampled, were infested with external mites. All stages of development: eggs, immature, and adults, were found. External mites of all three species found in package bees at Laramie last spring (2nd Quarterly Report 1961: page 8, and Tables 4 = 5), were still present on the bees in December. These include the back mite: Acarapis dorsalis, the neck mite: Acarapis externus, and the wing mite: Acarapis vagans. These are believed to be the first reports of their occurrence in Wyoming.

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Bee Disease Investigations, Laramie, Wyo.
Period: Apr 1 – Jun 30, 1962 with Quarterly Progress Report labeled Administratively Confidential. Work Project ENT c10, Line Project ENT c10-1: Biology of diseases and pests of honey bees and development of control methods, 7. Paralysis, page 10, 8. External Mites, page 11.

ABSTRACT:
About 2% of package bees received from Louisiana were infested with external mites. Eggs, immature, and adult mites were found of both the back mite, Acarapis dorsalis, and the wing mite, A. vagans. Page #11, 8. External Mites. Samples of 30 bees were examined from each of 12 queenless packages received from Louisiana, for external Acarapis mites. The back mite, A. dorsalis, was found on 4 individual bees, and the wing mite, A. vagans was found on 4 other individual bees. The neck mite, A. externus was not found. Thus, about 2% of the bees were infested with external mites. All stages: eggs, immature, and adult; and both sexes: male and female, of the mites were seen. They are considered of no economic importance.

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Bee Disease Investigations, Laramie, Wyo.
Period: Jan 1 – Mar 31, 1965 with Quarterly Progress Report labeled Administratively Confidential.
Work Project ENT c10, Line Project No. and Title: ENT c10-1(c), Biology of bee diseases and development of control methods for diseases and pests., 6. External Mites: On honey bees from California and Wyoming, Page 6.

ABSTRACT:
External mites: Acarapis dorsalis and Acarapis vagans were found on the back or wings, respectively, of a small percentage of honey bees from Fresno, California, and Laramie, Wyoming. No neck mites were found. Page #6. 6. External mites: On honey bees from California and Wyoming. Sample bees from all 6 packages from dwindling colonies received from Fresno, California, in mid-February were examined for external mites. “Back mites”: Acarapis dorsalis, were found in the dorsal groove of 3 out of 30 bees examined from package #5, and also “Wing Mites”: A. vagans, (eggs and larvae only), from 2 other bees of the same sample, and also from 2 bees out of 30 examined from Package #4. No “Neck mites”: A. externus, were found. An additional 189 bees from Package #5 were then examined individually for external mites and 2 bees were found with back mites, plus 7 with wing mites. Thus a total of 14 bees out of 219 examined, or only about 6%, were infested with external mites. Samples of 30 bees per colony were also examined March 16, 1965, for external mites from all 13 colonies in our Canal apiary at Laramie. Again, wing or back mites were found on 1 to 3 bees per sample in 5 of the colonies, and 1 adult mite with 1 egg, presumably A. vagans, was also found on the base of the abdomen of a single bee. No neck mites were found.

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Bee Disease Investigations, Laramie, Wyo.
Period: Oct 1 – Dec 31, 1969 with Quarterly Progress Report labeled For Official Use Only, with following: This progress report includes tentative results of research not sufficiently complete to justify general release. Such findings, when adequately confirmed, will be released promptly through established channels. Therefore, this report is not intended for publication and should not be referred to in literature citations. Work Unit/Project No. 00 ENT C1005 5301 00. bee Disease Control, External mites on honey bees, page 6.

ABSTRACT:
Acarapis dorsalis mites were found breeding in the dorsal scutellar groove on the thorax of adult worker honey bees sampled in December from an apiary established last spring with package bees from California. The same apiary also had bees infested with immature stages of a similar mite, presumably Acarapis vagans, breeding on the wings or on the front part of the abdomen. All bees were individually examined under a dissecting microscope, also for Acarapis externus, known to breed in the ventral neck region, but none was found. Twelve of 22 colonies in this apiary were found infested with external mites. These included 3 colonies infested with the “back” mite, 2 infested with the “wing and abdomen” mite , and 3 infested with both species. Another apiary of 23 colonies, previously over wintered in Laramie, also sampled in December, was found to be free of infestation by external mites.

Page #6. External mites on honey bees (Hitchcock). External mites of presumably 2 species were found among sample honey bees collected in mid-December from colonies established last spring in Laramie, Wyoming, with package bees imported from central California. thirty bees were examined individually under a dissecting microscope from each of 22 colonies. Each bee was examined for adult mites, or their eggs or immature stages, on 8 possible breeding sites: 1. Dorsal scutellar groove of the thorax, 2. Under side of left fore wing, 3. Upper side of left hind wing, 4. Under side of right fore wing, 5. Upper side of right hind wing, 6. Anterior-dorsal broad surface of the apparent 1st (true 2nd) abdominal segment, 7. Ventral neck or cervix, 8. Feste of the proboscis (or groove into which tongue is folded back). Ten of the colonies were negative for mites, but the other 12 colonies had from 1 to 3 bees infested with external mites, out of the 30 bees examined from each colony.

A total of 29 bees had eggs, immature, or adult mites in the scutellar groove on the thorax: undoubtedly the “back” mite: Acarapis dorsalis. eggs or immature mites were found on the wings of 3 bees and on the abdomen of 3 bees. These are presumed to be the “wing and abdomen” mites: Acarapis vagans, but unfortunately no adult mites were found on those breeding sites at this time of the year. All the bees wee also examined in the neck regions for the “neck” mites: Acarapis externus, but none were found. 5 colonies had bees infested with the “back” mites, 2 colonies had bees infested with the “wing and abdomen” mites, and 5 colonies had mixed infestations with both these mites. Even one individual bee had a mixed infestation of mite eggs: both in the scutellar groove on the thorax and on the under side of its left fore wing. External mites were found about 11% of the bees examined from the infested colonies, and on about 6% of all bees examined from this package apiary. No external mites were found on honey bees sampled from 23 colonies, previously over wintered in Laramie, from 1 other apiary, sampled in early December.

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Bee Disease Investigations, Laramie, Wyoming.
Period: Jan 1 – Mar 31, 1970 with Quarterly Progress Report labeled For Official Use Only, with following: This progress report includes tentative results of research not sufficiently complete to justify general release. Such findings, when adequately confirmed, will be released promptly through established channels. Therefore, this report is not intended for publication and should not be referred to in literature citation. Work Unit/Project No. 00 ENT C1005 5301 00 Bee Disease Control, External Mites on Honey Bees (Hitchcock), page 8, Table 6. External Mites on Honey Bees in Over wintering Colonies at Laramie, Wyoming, page 9; Table 7. Distribution of External Mites in Different Breeding Sites in individual Colonies, page 9; Table 8. Distribution of External Mites in Different Breeding Sites on individual Bees, page 10; Table 9. External mites found in the scutellar groove on the thorax of honey bees (Sagebrush apiary): Distribution and frequency of developmental stages, page 10; Table 10. External mites found on the wings of honey bees (Sagebrush apiary): Distribution and frequency of developmental stages, page 11; Table 11. External mites found on the abdomen of honey bees (Sagebrush apiary): Distribution and Frequency of developmental stages, page 11.

ABSTRACT:
External Acarapis mites were found on honey bees in 62% of our colonies, and in 7 out of 8 of our apiaries. In the infested colonies, about 10 percent of the bees were infested. The mites are of at least two species: Acarapis dorsalis breeding in the scutellar groove near the posterior dorsal part of the thorax, and A. vagans breeding on the wings or on the front portion of the abdomen. All bees were also examined under the neck for A. externus, known to breed there, but none was found. Many colonies (37%) had multiple mite infestations on the thorax, wings, and abdomen. Individual bees were infested most frequently on the thorax (40%), and least frequently on the abdomen (13%).

The average numbers of mites of all developmental stages occurring on individual bees were about 1 1/2 on the wings, 2 on the thorax, and 3 1/3 on the abdomen. The maximum number observed was 2 adults + 4 eggs + 11 immature equals 17 mites on the abdomen of a single bee. It is interesting that the severely nosema diseased colony also had an exceptionally high percentage (60%) of its bees infested with external mites Acarapis spp. on its thorax, wings, and abdomen. This severely nosema diseased colony died within 3 weeks after sampling, and the equipment was removed from the apiary.

Page #8, Esternal Mites on Honey Bees. (Hitchcock). A survey was made for external mites on honey bees in over wintering colonies in all our apiaries at Laramie, Wyoming. A sample of 30 bees from each colony was obtained, and the bees were examined individually under a dissecting microscope, on 8 possible breeding sites (Laramie 4th Qtly. Rpt. 1969, p.6). The data are summarized in Table 6. External mites were found in 81 of 131 colonies (62%), in 7 of 8 apiaries. Mites were found on about 10% of the bees in the infested colonies of all apiaries. However, the average infestation was as high as 15% in one (Harnden) apiary, where one very weak colony had a high mite infestation (60%), and also very severe (93%) nosema disease. Perhaps such internally parasitized bees do not have the strength to attempt to brush off external parasites. The mites were apparently of two species: Acarapis dorsalis, which breeds in the scutellar groove on the thorax, and A. vagans, which breeds on the wings and abdomen. All bees were examined under the neck also, for A. externus which is known to breed there, but none was found.

The distribution of mites in different breeding sites on the bees in different colonies is summarized in Table 7. This shows that colonies most frequently had bees infested on the thorax, and least frequently infested on the abdomen. Multiple infestations of more than one breeding site were very common, occurring in 37% of the infested colonies. The distribution of mites in different breeding sites on individual bees is summarized in Table 8. About 40% had mites on the thorax only, 35% had mites on the wings only, 13% had mites on the abdomen only, and about 10% had multiple infestations of more than one breeding site. Infestations of the wings and abdomen, on the same individual bees were more frequent (about 75), then infestations of either the thorax and wings or the thorax and abdomen (1.6 each). This may be another indication that the mites breeding on the wings and abdomen are the same species.

Page #12, It was observed that the mites on the wings always occurred on the under side of the front wings or the upper side of the hind wings. When the wings are folded over the bee’s abdomen, as normally occurs when inside the cluster of bees within the hive, the mites would be between the front and hind wings, and thus would be protected from getting rubbed off by other bees. Mites on the abdomen occurred on the front vertical portion, normally held close to the back of the thorax. Thus they were between these two main body segments, and again were protected from rubbing against other bees of the cluster. Mites on the thorax breed in the comparatively deep scutellar groove near the posterior portion of the top of the thorax, in which groove they cannot be rubbed off by contact with other bees.

Tables 9, 10, and 11 summarize the numbers of each development stage of mite, found on individual bees, on each of the 3 breeding sites: thorax, wings, and abdomen, for the bees from our largest (Sagebrush ) apiary. The average number of mites of all stages (eggs, immature, and adults) on a single honey bee was about 1 1/2 on the wings, 2 on the thorax, and 3 1/3 on the abdomen. The maximum number of mites on all stages on a single bee was 4 on the thorax, 4 on the wings, and 8 on the abdomen. However, in another apiary, 2 adults + 4 eggs + 11 immature, or a total of 17 mites were found on the abdomen of a single honey bee! The frequency of infestation of individual bees by mites of different developmental stages is also shown in Tables 9-11. Bees infested on the thorax were most frequently infested with eggs only. Bees infested on the wings were infested about equally with eggs only or by immature stages only.

Comparatively few bees were infested on the abdomen, but a high proportion of these (11 out of 19) had infestations by two or three stages of mites simultaneously. It was observed that the eggs and immature stages of mites occurring in the scutellar groove on the thorax were tightly “glued” to the adjacent hairs. When they were removed with a fine needle, many hairs broke off, but the eggs and immature stages were easily floated off the needle into a drop of water or of 20% glycerine. By contrast, the eggs and immature stages of mites occurring on the wings or abdomen were “glued” very tightly to the membrane wings or the the comparatively smooth surface of the front of the abdomen. It was very difficult to pry them off with a needle, and when this was accomplished, they adhered very firmly to the needle, so that it was difficult to transfer them to a drop of fluid on a microscope slide.

Page #13, A number of adult mites from each of the above three breeding sites on honey bees were preserved in Hoyer’s,s medium on microscope slides. Those from the scutellar groove have the characters distinctive for Acarapis dorsalis: namely, an apodeme the full length of the propodosoma, and the rear margin of the coxal plate (between the hind legs) having a deep indentation between two broadly rounded lobes (Micheal, 1962). The mites from the wings or abdomen have a short apodeme (about 2/3 the length of the propodosoma).

The shape of the rear margin of their coxal plate is very difficult to determine, and has not been clearly seen in enough individuals to determine its exact character. It appears to be almost truncate, like that of A. externus, the neck mite. However, in some individuals it appears to be a slightly rounded lobe without any indentation. In most specimens it is obscured by internal structures or elements–perhaps including ova or feces. If it is identical to A. externus, it seems strange that not a single mite of any developmental stage was found breeding under the neck of any of the nearly 4000 bees examined individually in this survey, where the neck mite is known to breed. Polaroid photographs have been taken which show the almost transparent eggs or immature mites attached to each of the three breeding sites: (1) scutellar groove of thorax, (2) beside a vein near the base of the wings, or (3) on the front of the abdomen.

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Bee Culture Investigations, Laramie, Wyo.
Period: Apr 1 – Sep 30, 1970 with Quarterly Progress Report labeled For Official Use Only, with following: This progress report includes tentative results of research not sufficiently complete to justify general release. Such findings, when adequately confirmed, will be released promptly through established channels. Therefore, this report is not intended for publication and should not be referred to in literature citations. Work Unit/Project No. 00 ENT C1005 5301 00 Bee Disease Control.

ABSTRACT:
Page #2, Only a slight amount of nosema disease was found in 5 out of 25 package colonies sampled in early May. The same package bees, received from California, had external mites on bees from 92% of the package colonies, and on about 15% of the bees in the infested colonies. These mites were found on 3 locations on the bees, bodies: the scutellar groove on the thorax, the wings, and the front portion of the abdomen. eggs, immature stages, and adult mites were found at each location. There was an average of 2 mites per bee on the thorax or wings, but about 3 1/2 mites per bee on the abdomen. The mites in the scutellar groove undoubtedly are Acarapis dorselis. those on the wings and abdomen are believed to be A. vagans. The underside of the neck of each bee also was examined for A. externus, known to breed on that location, but none was found. Single colonies occasionally included different bees infested with mites on all 3 body locations. Individual bees occasionally had mites on both the thorax and wings, or both the wings and abdomen, but not on both the thorax (scutellar groove) and abdomen.

Page #20, External Mites on Honey Bees (Hitchcock). Samples of 30 worker honey bees from each colony were obtained on May 5, 1970, from 25 package colonies, obtained from Davis, California, established in our Gunnerson apiary. each individual bee was examined under a dissecting microscope to determine the number and distribution of mites on various body regions of the bees. The data are summarized in Table 17. External mites were found in 92% of the packages. Mites occurred on 14.5% of all the bees examined from the infested colonies.

Page #21, Table 18 summarizes additional data on the numbers of honey bees having various numbers of each stage of the mites on various body regions. While comparatively few bees were found infested with mites on their abdomens, these mites were more abundant per bee, than mites on the thorax or wings. The average number of mites of all stages: eggs, immatures, and adults, occurring on the front part of the bees, abdomen was nearly 3 1/2 mites, compared to averages of about 2 mites per bee for those on the thorax or wings. Photographs were taken of mites on each body region. The mite species occurring in the dorsal scutellar groove on the thorax is undoubtedly Acarapis dorsalis. The mites occurring on either two wings or abdomen are believed to be A. vagans, but more detailed observations of their microscopic anatomy, on more specimens, are needed to confirm their identify, and to ascertain that mites on both the wings and abdomen are the same species. The underside of the necks of all bees sampled from these package colonies was also examined for the neck mites: A. externus, but none was found.

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Bee Culture Laboratory, Beltsville, Md.
Period: Apr 1 – Jun 30, 1959.
Page 6, A survey of Acarapis mites on honey bees in the United States was initiated during this quarter. Twenty-three routine samples from Connecticut, Florida, Georgia, Idaho, Kentucky, Maryland, Mississippi, New Mexico, Pennsylvania, Texas, Virginia, and North Carolina were examined for the presence of external and internal mites. In addition, thirty special samples from Wisconsin and ten samples from Wyoming were also subjected to the same examination. No external or internal mites were found in the total of 63 samples. Additional samples from other geographic areas will be solicited during the next quarter.

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Bee Culture Laboratory, Beltsville, Md.
Period: Jul 1 – Sep 30, 1959.
Forty-eight samples of bees were examined for the presence of Acarapis mites. No Tracheal mites were found but a mite was recovered from one sample by washing. This mite has been sent to the National Museum for identification.
Page #5, The survey of Acarapis mites on honey bees in the United States was continued during this quarter. Forty-eight samples of adult bees were examined for the presence of external and internal mites. In excess of 1,000 individual dissections for tracheal mites were made with negative results. A mite was recovered by washing from a sample of bees obtained from Louisiana. This mite has been sent to the National Museum for final identification. additional samples have been requested from the apiary from which the mite was obtained.

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Bee Culture Laboratory, Beltsville, Md.
Period: Oct 1 – Dec 31, 1959.
One hundred and seventy-three samples of bees were examined for the presence of Acarapis mites. One hundred and eighteen of these samples were found to be infested with external Acarapis. The positive samples were from the states of California, Utah, and Maryland. No tracheal mites were found in over 5,000 dissections of bees from these samples. A sample of Acarapis woodi infested dead bees in alcohol was received from Italy. These bees wee sent by Dr. Giordani for demonstration purposes.

Page #6, II. REPORT OF PROGRESS (Continued). The survey of Acarapis mites on honey bees in the United states was continued during this quarter. One hundred seventy-three samples of bees were examined for the presence of external and internal mites. More than 5,000 individual dissections for tracheal mites were made with negative results. However, examinations revealed 118 of these samples to be infested with external acarapis. One hundred fifteen of these samples were from Shasta County, California, and were examined for confirmation of the findings of the California workers. One sample of bees from Utah and 2 samples of bees from the laboratory apiary at Beltsville, Md., were found to be infested with external Acarapis. A change in technique for external mites has resulted in easier detection of the presence of these mites on bees. Approximately a dozen bees are placed in a petri dish and wetted with a 1 to 10,000 solution of triton X-100. This wetting agent is forcibly ejected from a plastic squeeze bottle directly onto each individual bee. The bees are then liberally washed with distilled water forcibly ejected from a plastic squeeze bottle directly onto each individual bee. This can be done rapidly until approximately 1/4 of an inch of fluid has collected in the petri dish. The presence of the Triton X-100 eliminates currents in the fluid and also causes the mites to settle to the floor of the petri dish. Examinations therefore can be made in a single plane under the dissecting microscope at a magnification of 20 times.

Page #7, The mites when located are easily removed from the fluid with a capillary pipette and transferred to a microscope slide for examination at higher power. Dr. Edward Baker, of our insect identification group at the National Museum, working with materials supplied by us and material obtained from the California workers has succeeded in locating a definite morphological difference between Acarapis woodi and the external mite under study which is apparently Acarapis dorsalis. Drawings demonstrating this difference are attached. A sample of dead bees infested with Acrapis woodi has been received from Italy. These bees were sent by Dr Giordani for demonstration purposes. Tracheal dissections are being made to obtain material for the preparation of microscope slides for our own files and for distribution.

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Bee Culture Laboratory, Beltsville, Md.
Period: Jan 1 – Mar 31, 1960.
I. SUMMARY OF PROGRESS. A total of 32 accessions were received for diagnosis. External mites were found to be present on bees obtained from Florida. An intensive survey of the diseases of adult bees in Maryland has been initiated.

Page #6, II. REPORT OF PROGRESS (Cont’d). The survey of Acarapis mites on honey bees in the United states was continued during this quarter. External mites, Acarapis dorsalis, were found to be present on bees from Florida. Mites other than Acarapis that have been recovered from samples of bees are as follows: Carpoglyphus, a widely distributed genus, found on dried fruits, milk products, glucose, decaying potatoes, flour, and many other food products. One species of Carpoglyphus has been recorded as breeding in large numbers inside bottles of wine in Paris, maintaining itself on floating pieces of cork and drawing nourishment from the wine. Glycyphagous domesticus, a species found in dried fruits, and organic matter such as skin and feathers, and is often found in enormous numbers in homes and stores. This mite also causes the “grocer’s itch” when highly infested material is handled. It has also been reported as the intermediate host of Catenotaemia pusilla, a cestode parasite of rodents. tydeus, mites that are worldwide in distribution and appear to be predaceous on small insects and mites and their eggs and Oribatid. Tyrophagus; Tarsonemus; Typhiodromus.

Page #8, II REPORT OF PROGRESS (Cont’d). Fifty-five microscope slides of Acarapis dorsalis and twenty-eight slides of Acrapis woodi have been completed. Upon receipt of additional A. woodi material from Italy, completion of these slides for distribution can be accomplished. The late winter and early spring in Maryland were unusually severe with resulting losses of approximately 10% of the colonies. Time has been devoted to apiary cleanup and preparation of equipment for spring management.

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Bee Culture Laboratory, Beltsville, Md.
Period: Apr 1 – Jun 30, 1960.
I. SUMMARY OF PROGRESS. A total of 244 accessions were received for diagnosis. Laboratory examinations totaled 948, and 3,810 individual dissections were made for tracheal mites. External mites were found on bees from the States of Georgia and West Virginia.
Page #6, II. REPORT OF PROGRESS (Cont’d). The survey of Acarapis mites on honey bees in the United States was continued during this quarter. Acarapis dorsalis was found to be present on bees from Georgia and West Virginia, two states from which they had not been previously reported. Dissections for the internal mite, Acarapis woodi, totaling 3,810, were made on 127 samples and all have been negative. A survey for adult bee diseases in the State of Maryland covering 103 apiaries revealed that 16.5% of these apiaries were harboring Nosema disease in detectable amounts; 4.9% of these apiaries were found to contain detectable infestations of external mites; and one apiary was found to contain Septicemia. It is planned to survey at least 400 apiaries in this study.

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Bee Culture Laboratory, Beltsville, Md.
Period: Jul 1 – Sep 30, 1960.
I. SUMMARY OF PROGRESS. A total of 197 accessions were received for diagnosis. Laboratory examinations totaled 790, and 3,150 individual dissections were made for tracheal mites. External mites were found on bees from the States of Mississippi and Tennessee. Sixty-five apiaries in Maryland were surveyed this quarter for adult diseases. Nosema disease was found in 25% of these apiaries, external mites in 7.5% of these apiaries, and Septicemia was found in one apiary. A spore-forming bacillus and an unidentified coccus were isolated from Wisconsin bees showing symptoms of paralysis. Both organisms demonstrated some pathogenicity for adult bees.

Page #6, II. REPORT OF PROGRESS (Cont’d). The survey of Acarapis mites on honeybees in the United States was continued during this quarter. Acarapis dorsalis was found to be present on bees from Mississippi and Tennessee, two states from which they had not been previously reported. Dissections for the internal mite, Acarapis woodi, totaling 3,150, were made on 105 samples and all were negative.

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Bee Culture Laboratory, Beltsville, Md.
Period: Oct 1 – Dec 31, 1960.
Page #2, I. SUMMARY OF PROGRESS (Cont’d). Sets of microscope slides of A. woodi and A. dorsalis have been prepared and distributed. A sample of Apis Indica received from Oregon contained mites identified as A. woodi.

Page #9, A series of 35mm. transparencies have been completed on the subject of Acarine mites of the honey bee. A set of these slides has been furnished to each of the Bee Culture laboratories. Two sets have also been sent to Mr. Seymour Bailey, President, Apiary Inspectors of America. A set of microscope slides of A. woodi and A. dorsalis have also been sent to each of the Bee Culture laboratories.

Page #10, A sample of Apis indica was received from the Oregon State Department of Agriculture for examination for Acarine disease. This sample was from experimental stock obtained from Japan in a double screen package and was to be maintained in a special bee room. Our examination did not reveal the presence of any mites in the trachea of these bees. However, when muscle sections were made of the anterior portion of the thorax including the anterior tracheae and the muscle mass was dissolved by lactic acid, mites were found with coxal plate configurations identified with Acarapis woodi.These mites were sent to Dr. E. W. Baker who identified them as A.woodi.

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Bee Culture Laboratory, Beltsville, Md.
Period: Apr 1 – Jun 30, 1961.
A 5-week’s visit was made to European laboratories in Italy, France, Switzerland, Germany, and England to study Acarine disease. Samples of dead preserved bees infested with A. woodi and A. vagans were brought back from Europe for additional study of differential characters of various species of honey bee mites.

Page #9, In Europe diagnosis of acarine disease in the apiary is considered of a presumptive nature. A colony with reduced supplies, a normal complement of young bees but low in numbers of foragers is suspect. A severe infestation results in a colony greatly reduced in strength, especially in the spring. Individual bees with wings unhooked are unable to fly, climb blades of grass, etc., or lay on the ground motionless or with wings vibrating ineffectively. These symptoms are mostly observed during the spring. In summer not many diseased or dead bees are found but more frequently weak colonies with reduced foraging activity are observed.


Signed: Dee A. Lusby, Amado, Arizona, USA