fig 10 hydrodroma despiciens dorsal
Howto recognize and identify the water mite Hydrodroma Despiciens.
Description following Soar & Williamson. Volume 1 – Page 160 – Plates 7 & 16.
In their book « british hydracarina » Soar & Williamson used the namee Diplodontus despiciens instead of Hydrodroma despiciens.
- Length up to 2mm and broadth of 1.7mm (my speciem is 1.6mm in length).
- Outline varying from a broad oval to almost circular, the anterior end sometimes slightly truncated.
- Body rather compressed dorso ventrally (see my fig 30)
- Dorsum very slightly arched.
- Skin closely covered with tapering pappilae, inclining obliquely toward posterior (my picture are not goo enought to see this character).
- Gland pores in four raw on dorsum, the outer rows of each side lying along lateral margins.
Note on the possibility of Hydrodroma pilosa.
Kinga Dzierzgowaska and Andrzej Zaw wrote a paper on Hydrodroma pilosa found in Poland. They site Gerecke to say that maybe 50% of Hydrodroma despiciens are in fact Hydrodroma pilosa.
Particularity of Hydrodroma pilosa.
- Swimming seate on II-leg-4-5and IV-leg-4-5
- Integument structure (see the figure 1 on the paper of Dzierzgowaska).
Behaviour.
- Hydrodroma despiciens eat mainly chironimids eggs. Their palps are well adapted to the mass jelly in which lie the eggs (P.R. WILES – Freshwater biology – 1982).
References.
- DZIERZGOWSKA, K., ZAW, A. 2010 : Hydrodroma pilosa Besseling, 1940 and Limnesiua undulatoides Davids, 1997 (ACari, Hydrachnidia) – New records from Poland. – Natura Montenegrina 9 (3): 451-455. (get the PDF)
Links
- Microcosmos.nl : Gerard Visser succeeded to get much better pictures than mines for the genital area.
- Agroeconet : in russian, pictures of ventral surface and palpi.
Mores pictures of Hydrodroma Despiciens.
fig 20 hydrodroma despiciens ventral
fig 30 frontal
fig 40 first 2 pair of legs
fig 50 setae on fourth pair of legs
fig 60 genital and anal area
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