Archive for June, 2011

Photo Magnet: Antennolaelaps Appreciation

June 25, 2011

Ventral view of gnathosoma of Antennolaelaps sp.

What do Antennolaelaps, Emmylou Harris, Catherine Deneuve, FDR, The BVM, and assorted ladies with musical instruments, ladies in informal attire (or not attired), and a couple of strange dudes have in common?

Results of a Google Image Search

It must be the colour scheme, but at least no algorithm has confused this attractive member of the Mesostigmata with Darth Vadar. That would only be appropriate for members of the genus Darthvaderum Hunt, 1996, a member of the Oribatida.

Hat tip to Myrmecos.

And the answer is …

June 18, 2011

Putative Mycetophagus prepupa with Paracarophenax

Well, Ted gets a point for the adult beetles – they are Mycetophagidae – and a species of Mycetophagus according to Arnett, although if the adult male beetle didn’t have a distinctive tarsal formula, I’m not sure I would have ever keyed it out. A coleopterist now has the specimens and a species identification may be forthcoming. The associated larva is not a Ciidae – I think these are restricted to polypore mushrooms and the habitat was a fleshy gilled mushroom, Pleurotus ostreatus.  My inference that the larvae associated with these adult beetles is the same species is based on co-occurance, appropriate size, and lack of any alternative. I’ll see if I can get a specialist to agree, but larvae don’t seem to be especially well known.

I think I’ll have to give Kaitlin the win here, though, with three points: one for recognising the mite as a member of the Heterostigmatina (aka Heterostigmata), one for a creative (if wrong) story about the life history, and one for boldly guessing where no other acarologist dared.

The mite is, in fact, an undescribed species of Paracarophenax Cross, 1965 (Acariformes: Heterostigmatina: Acarophenacidae). Of the five described species in the genus (Magowski 1994), Paracarophenax dermestidarum (Rack, 1959) seems to be the only species that has been studied in any detail – it is a parasitoid of the eggs of a dermestid beetle. However members of other genera in the family are of considerable interest as biocontrol agents of stored product beetles.

For example, Acarophenax lacunatus (Cross & Krantz, 1964) is an egg parasitoid of a number or grain-infesting beetles (Oliveira et al. 2003a,b) including the Lesser Grain Borer Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae). Adult female mites are phoretic on adult beetles. The mites detach from the beetle as eggs are laid. A mite attaches to the egg, swells up (physogastry), and as it kills the egg up to two dozen offspring develop inside the body of the mother mite (Faroni et al. 2000). One or two of these internal young are males and they mate their sisters before they pop open the mother and start looking for new eggs or new beetles to hitch rides on.

This seems to be the general life style of these mites, including those in the genus Adactylidium Cross, 1965 on thrips eggs and Aeithiophenax Mahunka, 1981 on the eggs of scolytine bark beetles. So, we may assume that our Paracarophenax does something similar. I’m not aware of reports of these mites attaching to larvae, but the three ‘Mycetophagus‘ larvae with mites were all large, plump, and probably prepupae (smaller larvae did not harbour mites). In the swampy morass of a decomposing oyster mushroom, I think it makes sense that the mites hang on (they were not feeding) to the late stage larva. One wonders where pupation takes place, but for the mites to have another generation, they need to hitch a ride on an appropriate insect.

Further reading:

Cross EA, Krantz, GW. (1964) Two new species of the genus Acarophenax Newstead and Duvall 1918
(Acarina:Pyemotidae). Acarologia, 6, 287-295.

Faroni LRD’A, Guedes RNC & Mathioli AL. (2000) Potential of Acarophenax lacunatus (Prostigmata:Acarophenacidae) as a biological control agent of Rhyzopertha dominica (Coleoptera: Bostrichidae). Journal of Stored Products Research, 36,  55-63.

Magowski WL. (1994) Discovery of the first representative of the mite subcohort Heterostigmata (Arachnidae:
Acari) in the Mesozoic Siberian amber. Acarologia, 35, 229±241.

Oliveira CRF, Faroni LRD’A, Guedes RNC. (2003a) Host egg preference by the parasitic mite Acarophenax lacunatus (Prostigmata: Acarophenacidae). Journal of Stored Products Research, 39, 571–575.

Oliveira CRF, Faroni LRD’A, Guedes RNC, Pallini A. (2003b) Parasitism by the mite Acarophenax lacunatus on beetle pests of stored products. BioControl, 48, 503–513.

Rack G. (1959.) Acarophenax dermestidarum sp.n. (Acarina, Pyemotidae), ein eiparasitic yon Dermestes arten. Z.  Parasitenkunde, 19, 411-431.

Acroseius, Polyaspinus, Trachytes: Cerotegument Galore

June 5, 2011

Acroseius - undescribed species from Queensland - venter

I recently had a request for an image of Polyaspinus tuberculatus Womersley, 1961 and I realised that my Polyaspididae, I mean Trachytidae (current usage), were not in very good nick. Actually, the mite in question is now Acroseius tuberculatus (Womersley, 1961) too.

Polyaspinus sp. (probably undescribed) from Queensland - venter

The short answer is that I do have images of what appears to be an undescribed species of Acroseius and also a probably undescribed species of Polyaspinus from Queensland. I also have an undescribed Polyaspinus from Alberta (no image yet) and a species of Trachytes  that is probably described from Oregon.

Trachytes sp. from Oregon - dorsum

All of these mites are interesting for several reasons, but I will have to wait to post on that – I’m being dragged off on family duties.


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