— TheViableBlog

How Varroa became destructor – The story of a name


Image: IBRA

The Varroa mite is widely recognized as today’s most serious pest of the Western Honeybee (Apis mellifera), so its rather menacing scientific name of Varroa destructor seems only natural and fitting.
However, when the mite was first discovered in Java in 1904, it had never even met a Western Honeybee, let alone damaged one, but was an altogether inconspicuous species living in a well-balanced relationship with the Eastern Honeybee (A. cerana). And A.C. Oudemans, who first described it as a species, may have been a remarkable man, but he was in no way prescient concerning the enormous threat the mite would become some hundred years later. He therefore named it, quite conventionally, Varroa jacobsoni after its collector.

For a long time, this was of little interest to anybody.

During this time, all Varroa mites were thought to belong to one of three species: V. jacobsoni, V. underwoodi, V. rindereri, with V. jacobsoni having the widest distribution on A. cerana and being the only species to parasitise A. mellifera. Which, of course, eventually, brought it to the attention of the bee researchers. Varroa jacobsoni soon became one of the closest studied mite species in the world.

Despite all this attention, there was very little morphological variation to be found within V. jacobsoni. From the outside, all mites looked the same. But there was a marked difference in their virulence toward A. mellifera. V. jacobsoni of Javanese origin, for example, were completely unable to reproduce on A. mellifera (and therefore much less damaging for the bees), whereas mites from other locations thrived on the western bees and caused great losses in managed and feral hives.

So the question was: What is different between the „harmless“ mites from Java and the virulent types from other places?

Dr. Denis Anderson

All through the 1990s, the Australian entomologist Denis Anderson and his colleagues had been collecting and comparing specimens of V. jacobsoni from all over the world. They found, that despite their uniform appearance, jacobsoni-mites were genetically quite diverse, and identified 18 haplotypes (mites with distinct sequences in their mitochondrial DNA) on A. cerana in Asia (the original host). Of these 18 haplotypes, only two had become pests of A. mellifera. The team also showed, that mites living on A. mellifera do not mix with mites living on A. cerana. They are reproductively isolated.

In the their publication in the year 2000, they concluded that

…the between-clade differences are sufficiently large to represent differences between species.

Meaning: They had discovered Varroa destructor.

For an insight into the reception of this discovery, I strongly recommend the guest editorial in Bee World from 2001 by Keith S. Delaplane, an entomologist at University of Georgia:

During the 1990s many workers contributed to the “revolution” that was heating up, but it was Anderson and Trueman who dealt the old paradigm its death blow. The mite we were all dealing with, we learned, was not Varroa jacobsoni at all. This much-maligned species turns out to be a benign homebody, still restricted essentially to its original host A. cerana in Indonesia as Jacobson found it, and not the culprit to worldwide calamity we had thought. For this we needed a new culprit, and Anderson and Trueman found it. They not only found it and named it, they named it in a glorious flourish of melodrama, appropriate in this case and all too rare in the stuffy halls of academe – Varroa destructor. Let your tongue roll on that one. Here’s a Linnaean name anyone can appreciate.

At the time, despite the “glorious flourish of melodrama”, there was hope that Varroa might be defeated through making use of the new genetic information. But so far, V. destructor is still thriving.

ResearchBlogging.org

Anderson DL, & Trueman JW (2000). Varroa jacobsoni (Acari: Varroidae) is more than one species. Experimental & applied acarology, 24 (3), 165-89 PMID: 11108385