Poly Hive
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Dr Rennie’s Teams’ Discovery of the Mite (Acarapis woodi (Rennie)) that caused Isle of Wight Disease
This most debilitating of bee diseases had first been identified amongst bees on the Isle of Wight around 1904 and was given the name from that island.
The disease was characterised by a general decrease in flying activity usually leading to bees being seen crawling about in front of the hive and typically attempting to crawl up blades of grass. The condition eventually leads to the colony dying out. It was very infectious and soon spread throughout the UK due to bees being transported from place to place.
It has the privilege of being one of the few bee diseases to receive a mention in Hansard, (4th June 1919) such was the concern that it was having on apiculture. The minister in charge of food replied to a question on dangers to the supply of honey from Isle of Wight Disease, that ….. the (Agriculture) Board are promoting research and investigation into the nature and causes of the Isle of Wight disease, with the view of ascertaining the best means of remedy or prevention….. Of course several MP’s kept bees, amongst them David Lloyd George, so there would be a natural interest on the subject within parliament.
The disease led to large losses and soon attracted the eye of the agricultural authorities. A research programme was initiated at Cambridge University in 1909 under Dr Malden who from 1911 through 1913 was joined by Drs Graham Smith, Fantham and Annie Porter. They concluded (erroneously) that the disease was caused by the microsporidium Nosema Apis (a disease of the gut of bees) and firmly focussed on this conviction, Drs Fantham & Porter proceeded to trace the life cycle of this organism. Something useful could therefore be said to have come out of this blind alley.
Dr John Rennie was a researcher at Aberdeen University under the famous educationalist, researcher, beekeeper and first editor of our magazine Dr John Anderson.
Rennie had earlier carried out research on human diabetes and in 1906 had come within an ace of identifying and establishing insulin as a treatment. He had noticed that the Langerhans tissue in Teleostean (bony as opposed to cartilaginous) fishes, formed a separate gland (this is part of the pancreas in we humans and other mammals) and suspected that it contained a substance vital to the metabolism of sugar (insulin). He had treated a patient with an extract. However because the extracted insulin was not of sufficient purity and due to lack of reliable supplies, the experiments had to be discontinued. It took a further 18 years to obtain insulin which was sufficiently pure to treat diabetes. The name insulin had been given by a Belgian researcher, Jean de Meyer in 1909, but later Canadian researchers (Banting & Best) had renamed it isletin (from the islets of Langerhans) – JJR McLeod (who shared the Nobel with Banting) insisted that they revert to the name insulin. Rennie was thus a heavy hitter as far as difficult research projects were concerned.
Due to the intensive beekeeping activities in the north of Scotland and especially in Aberdeenshire, Isle of Wight disease was very much on the minds of the northern beekeepers and researchers and from 1913 onwards a serious investigation was commenced with funding from the Development Commissioners, The University of Aberdeen and The North of Scotland College of Agriculture. An English sportsman, engineer and beekeeper, who had spent some of his childhood and finally settled in Scotland, Mr A H E Wood of Glassel House (near Banchory) in Aberdeenshire made the very generous offer of 500 guineas (£525) per annum for 3 years, provided the Government’s Development Commissioners would match the funding (£525 then, would today be equivalent to about £150,000 - on a researcher earnings basis). Mr Wood is also credited with the development of the floating line method of fly-fishing for salmon and sea trout. This fund put the search for the cause of Isle of Wight disease, on a sound footing.
In spite of the Cambridge results the northern researchers (especially John Anderson in 1916) were sceptical of the Nosema apis conclusion as they had witnessed bees with Isle of Wight disease and an absence of the microsporidium Nosema. Subsequently the researcher Dr Whole (USA) had also doubted Nosema and had suggested that Nosema was an altogether separate debilitating disease.
The researchers John Rennie, Philip Bruce White and Elsie J Harvey set about the tedious research task of observing, testing – colony after colony, district after district. Finally in Dec 1919, after examining 3000 bees from 250 colonies throughout the UK (110 colonies of which were reported as having the disease), the first mite, (1/6th mm long),was identified by Elsie Harvey in part of a trachea (breathing tube) attached to a previously prepared sample of a thoracic (salivary) gland. The mite, a hitherto unidentified species was considered by Rennie as belonging to the genus Tarsonemus and given the name Tarsonemus woodi, in deference to the benefactor Mr Wood. However it was subsequently identified by Stanley Hirst, the British Museum mite specialist as a completely new genus and given the name Acarapis woodi (Wood’s mite of the Bee). However the scientific convention for naming new species after the discoverer has meant that it is now universally referred to as Acarapis woodi (Rennie).
The following May, the third member of Rennie’s team, Philip Bruce White, made the discovery that mites in all stages of development were present in the major thoracic trachea in “crawling” bees. He had found the mites in 100% of a sample of 150 sick bees (gathered from several diseased colonies) and failed to find mites in 95% of apparently healthy bees. Eggs, larvae, nymphs and adults were found in the anterior thoracic spiracle (entrance to the frontal breathing tubes) of bees that were exhibiting signs of Isle of Wight disease. Adult mites were seen to have crawled down the smaller branches of the breathing tubes right to the point where they had completely blocked the tube. Mr White’s observation locked in the new mite as the culprit in the Isle of Wight scourge.
Their discovery was reported in a scientific paper read to The Royal Society of Edinburgh on Nov 1, 1920 and the paper was issued on Mar 25, 1921.
The fact that the mites damaged (typical blood-suckers as with all mites) and even blocked the bee’s main breathing tubes explained why the bees couldn’t fly and showed all the signs of “breathlessness”. Much later in the 1950’s, Dr Bailey in the Bee Disease Section of the Rothamsted Research Station, identified that the virus Chronic Bee Paralysis Virus was spread by the mite and suggested that many of the colony losses in the 1920’s was ultimately due to attack by this virus.
Having discovered the cause of Isle of Wight disease meant that a sure-fire, five minute, side-of-hive method of diagnoses soon followed. The method comprises impaling a bee with two dressmaking pins, on its back on the flat of a bottle cork. The head is then pushed back and off with a small blade to expose the large trachea just below the collar. Using a jeweller’s eyeglass the trachea can now be examined (the mites themselves are too small to see at this magnification). The trachea is shaped somewhat like a miniature clothes hanger and a healthy mite-free trachea tube is milky-white. A discoloured, brown or blackened tube indicates the presence of acarine mites.
However discovery and diagnosis was but part of the task, a combatant was now required. In 1927 (a year before his death at age 63), Dr Rennie suggested that sulphur fumes would possibly control the disease. The method involved dissolving sulphur in carbon disulphide, a tricky and expensive operation leading to a highly inflammable product. It was never used in the UK being displaced by the simpler Frow mixture (2 parts nitro-benzene, 1 part safrol oil & 2 parts petrol (non-leaded)). However Rennie’s formula was used in Switzerland where Frow mixture did not work very well because of the low temperature. Note- nitro-benzene not nitro-glycerine, as once requested of his local chemist by an old Edinburgh beekeeper, much to the consternation of the poor chemist, (nitro-glycerine is an altogether more unstable and explosive mixture).
Later on, the Ministry of Agriculture described treatment with Folbex strips, an early synthetic miticide. No doubt the Varroa miticides will also have had an effect on depressing the numbers of Acarine mites.
There have been many remedies proposed and used but due to the early heavy losses throughout the UK, bees which were more genetically resistant to Acarine disease were imported, especially from Italy, France and the Netherlands and the effect of the disease gradually reduced. It was however one of the diseases that concerned Brother Adam and when he developed his Buckfast Bee strain he concentrated on getting a strain that was genetically resistant to Acarine disease. It no longer carries the fear that it once inspired in beekeepers but it was the “varroa” epidemic of our forefathers and Rennie’s breakthrough was a major step in dispelling the fear of the unknown.
Dr Rennie became the first president of the Apis Club (founded by Dr Abushady in 1919) and received the Club’s Gold Medal in 1924 in recognition of leading the team that solved the great mystery.
Tom McGravie & Alan Riach
Informative indeed.
PH
This most debilitating of bee diseases had first been identified amongst bees on the Isle of Wight around 1904 and was given the name from that island.
The disease was characterised by a general decrease in flying activity usually leading to bees being seen crawling about in front of the hive and typically attempting to crawl up blades of grass. The condition eventually leads to the colony dying out. It was very infectious and soon spread throughout the UK due to bees being transported from place to place.
It has the privilege of being one of the few bee diseases to receive a mention in Hansard, (4th June 1919) such was the concern that it was having on apiculture. The minister in charge of food replied to a question on dangers to the supply of honey from Isle of Wight Disease, that ….. the (Agriculture) Board are promoting research and investigation into the nature and causes of the Isle of Wight disease, with the view of ascertaining the best means of remedy or prevention….. Of course several MP’s kept bees, amongst them David Lloyd George, so there would be a natural interest on the subject within parliament.
The disease led to large losses and soon attracted the eye of the agricultural authorities. A research programme was initiated at Cambridge University in 1909 under Dr Malden who from 1911 through 1913 was joined by Drs Graham Smith, Fantham and Annie Porter. They concluded (erroneously) that the disease was caused by the microsporidium Nosema Apis (a disease of the gut of bees) and firmly focussed on this conviction, Drs Fantham & Porter proceeded to trace the life cycle of this organism. Something useful could therefore be said to have come out of this blind alley.
Dr John Rennie was a researcher at Aberdeen University under the famous educationalist, researcher, beekeeper and first editor of our magazine Dr John Anderson.
Rennie had earlier carried out research on human diabetes and in 1906 had come within an ace of identifying and establishing insulin as a treatment. He had noticed that the Langerhans tissue in Teleostean (bony as opposed to cartilaginous) fishes, formed a separate gland (this is part of the pancreas in we humans and other mammals) and suspected that it contained a substance vital to the metabolism of sugar (insulin). He had treated a patient with an extract. However because the extracted insulin was not of sufficient purity and due to lack of reliable supplies, the experiments had to be discontinued. It took a further 18 years to obtain insulin which was sufficiently pure to treat diabetes. The name insulin had been given by a Belgian researcher, Jean de Meyer in 1909, but later Canadian researchers (Banting & Best) had renamed it isletin (from the islets of Langerhans) – JJR McLeod (who shared the Nobel with Banting) insisted that they revert to the name insulin. Rennie was thus a heavy hitter as far as difficult research projects were concerned.
Due to the intensive beekeeping activities in the north of Scotland and especially in Aberdeenshire, Isle of Wight disease was very much on the minds of the northern beekeepers and researchers and from 1913 onwards a serious investigation was commenced with funding from the Development Commissioners, The University of Aberdeen and The North of Scotland College of Agriculture. An English sportsman, engineer and beekeeper, who had spent some of his childhood and finally settled in Scotland, Mr A H E Wood of Glassel House (near Banchory) in Aberdeenshire made the very generous offer of 500 guineas (£525) per annum for 3 years, provided the Government’s Development Commissioners would match the funding (£525 then, would today be equivalent to about £150,000 - on a researcher earnings basis). Mr Wood is also credited with the development of the floating line method of fly-fishing for salmon and sea trout. This fund put the search for the cause of Isle of Wight disease, on a sound footing.
In spite of the Cambridge results the northern researchers (especially John Anderson in 1916) were sceptical of the Nosema apis conclusion as they had witnessed bees with Isle of Wight disease and an absence of the microsporidium Nosema. Subsequently the researcher Dr Whole (USA) had also doubted Nosema and had suggested that Nosema was an altogether separate debilitating disease.
The researchers John Rennie, Philip Bruce White and Elsie J Harvey set about the tedious research task of observing, testing – colony after colony, district after district. Finally in Dec 1919, after examining 3000 bees from 250 colonies throughout the UK (110 colonies of which were reported as having the disease), the first mite, (1/6th mm long),was identified by Elsie Harvey in part of a trachea (breathing tube) attached to a previously prepared sample of a thoracic (salivary) gland. The mite, a hitherto unidentified species was considered by Rennie as belonging to the genus Tarsonemus and given the name Tarsonemus woodi, in deference to the benefactor Mr Wood. However it was subsequently identified by Stanley Hirst, the British Museum mite specialist as a completely new genus and given the name Acarapis woodi (Wood’s mite of the Bee). However the scientific convention for naming new species after the discoverer has meant that it is now universally referred to as Acarapis woodi (Rennie).
The following May, the third member of Rennie’s team, Philip Bruce White, made the discovery that mites in all stages of development were present in the major thoracic trachea in “crawling” bees. He had found the mites in 100% of a sample of 150 sick bees (gathered from several diseased colonies) and failed to find mites in 95% of apparently healthy bees. Eggs, larvae, nymphs and adults were found in the anterior thoracic spiracle (entrance to the frontal breathing tubes) of bees that were exhibiting signs of Isle of Wight disease. Adult mites were seen to have crawled down the smaller branches of the breathing tubes right to the point where they had completely blocked the tube. Mr White’s observation locked in the new mite as the culprit in the Isle of Wight scourge.
Their discovery was reported in a scientific paper read to The Royal Society of Edinburgh on Nov 1, 1920 and the paper was issued on Mar 25, 1921.
The fact that the mites damaged (typical blood-suckers as with all mites) and even blocked the bee’s main breathing tubes explained why the bees couldn’t fly and showed all the signs of “breathlessness”. Much later in the 1950’s, Dr Bailey in the Bee Disease Section of the Rothamsted Research Station, identified that the virus Chronic Bee Paralysis Virus was spread by the mite and suggested that many of the colony losses in the 1920’s was ultimately due to attack by this virus.
Having discovered the cause of Isle of Wight disease meant that a sure-fire, five minute, side-of-hive method of diagnoses soon followed. The method comprises impaling a bee with two dressmaking pins, on its back on the flat of a bottle cork. The head is then pushed back and off with a small blade to expose the large trachea just below the collar. Using a jeweller’s eyeglass the trachea can now be examined (the mites themselves are too small to see at this magnification). The trachea is shaped somewhat like a miniature clothes hanger and a healthy mite-free trachea tube is milky-white. A discoloured, brown or blackened tube indicates the presence of acarine mites.
However discovery and diagnosis was but part of the task, a combatant was now required. In 1927 (a year before his death at age 63), Dr Rennie suggested that sulphur fumes would possibly control the disease. The method involved dissolving sulphur in carbon disulphide, a tricky and expensive operation leading to a highly inflammable product. It was never used in the UK being displaced by the simpler Frow mixture (2 parts nitro-benzene, 1 part safrol oil & 2 parts petrol (non-leaded)). However Rennie’s formula was used in Switzerland where Frow mixture did not work very well because of the low temperature. Note- nitro-benzene not nitro-glycerine, as once requested of his local chemist by an old Edinburgh beekeeper, much to the consternation of the poor chemist, (nitro-glycerine is an altogether more unstable and explosive mixture).
Later on, the Ministry of Agriculture described treatment with Folbex strips, an early synthetic miticide. No doubt the Varroa miticides will also have had an effect on depressing the numbers of Acarine mites.
There have been many remedies proposed and used but due to the early heavy losses throughout the UK, bees which were more genetically resistant to Acarine disease were imported, especially from Italy, France and the Netherlands and the effect of the disease gradually reduced. It was however one of the diseases that concerned Brother Adam and when he developed his Buckfast Bee strain he concentrated on getting a strain that was genetically resistant to Acarine disease. It no longer carries the fear that it once inspired in beekeepers but it was the “varroa” epidemic of our forefathers and Rennie’s breakthrough was a major step in dispelling the fear of the unknown.
Dr Rennie became the first president of the Apis Club (founded by Dr Abushady in 1919) and received the Club’s Gold Medal in 1924 in recognition of leading the team that solved the great mystery.
Tom McGravie & Alan Riach
Informative indeed.
PH
