Hymenoptera

A Less Notorious Bee Mite

The mite Varroa destructor has become famous in the wake of colony collapse disorder as a nasty parasite of the domestic honey bee Apis mellifera. But it is not the only bee-associated member of the family Varroidae, nor is A. mellifera the only host of varroids. Last week a former honours student of mine, Dr. Geoff Williams, sent me specimens of Euvarroa from a nest of the dwarf honey bee Apis florea Fabricius from just north of Chiang Mai in Thailand, where they had been collected by a local student, Patcharin Phokasem.

Like Varroa, Euvarroa are very large, heavily sclerotized mites. The ones that Geoff sent were 1 mm long: five Notoedres from a mangy squirrel skin could lie nose-to-tail on the venter of one Euvarroa.

Euvarroa with Notoedres

Euvarroa sinhai is a big mite, shown here with a 200 um long Notoedres for scale.

There are two named species in the genus Euvarroa, E. sinhai Delfinado & Baker and E. wongsirii Lekprayoon & Tangkanasing. Euvarroa sinhai is associated with Apis florea, whereas E. wongsirii is found on A. andreniformis Smith.  The species differ in general body shape (very triangular for E. wongsirii) and length:width ratio for the anal plate (longer than wide in E. sinhai, the opposite for E. wongsirii)*. Based on these host and morphological features, the mites from Geoff are E. sinhai.

I don’t think that much is known of the biology of either Euvarroa species, but they are very spiffy-looking mites. Here are some closer views of parts of their anatomy.

Euvarroa chelicera

The bee-piercing chelicerae of Euvarroa sinhai.

Euvarroa peritreme

Euvarroa sinhai‘s u-shaped peritreme; stigma to the upper left.

Euvarroa ambulacrum

“My, what big ambulacra you have!” “All the better for holding onto bees, my dear.”

*Lekprayoon, C. and P. Tangkanasing. 1991. Euvarroa wongsirii, a new species of bee mite from Thailand. International Journal of Acarology 17: 255–258.