A mite with a mite problem

5 hypopi hitching a ride on an Athiasiella

This morning Myrmecos Blog, the place to go for spectacular ant pictures, links to a picture on Flickr by Brian Valentine of a couple of red ants from a compost heap covered with mites. I especially like the ones sticking to the foreground ant’s eye. These look like the dispersal stage of another Astigmatina, possibly a species of the acarid genus Sancassania, as they are common in decomposing material, but then so are several other families. If the compost is very wet and stinky, then they may be Histiostomatidae. The dispersal stages are technically called ‘heteromorphic deutonymphs’, but an older term ‘hypopus’ (plural – hypopi) is easier on the tongue. Hypopi are bizarre for a number of reasons. For example, most have some of their posterior ventral setae modified into a sucker plate that allows them to latch onto surfaces such as insect cuticle – or that of larger mites for that matter. Actually anthing with an appropriate surface that wanders through a compost heap can become covered with [these] little hitchhikers – the famous Australian medical acarologist, Bob Domorow, once published a picture in Acarologia of a skink absolutely encased in [hypopi] CORRECTION – deutonymphs, yes, but of a uropodid mite, not astigmatine hypopi.  See Domrow, R. 1981. A small lizard stifled by phoretic deutonymphal mites (Uropodina). Acarologia 22:247–52

Hypopus underside – note tiny ‘head’ and sucker plate (bottom)

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Tags: phoresy