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Midas Fly - Messiasia pertenuis

Midas Fly - Messiasia pertenuis
U of A, Pima County, Arizona, USA
July 14, 2011

Margarethe: Can you provide additional habitat or other details?
Reading the location info field for your post...I'm wondering if you found this flitting around a kangaroo rat nest in a random sand dune on the U of A campus?? :-)

Or perhaps in a lab terrarium, or just resting on a desk or in a drawer in some room in the entomology department?? ;-)

On vegetation
on campus. No sand dunes anywhere, just irrigated gardens

...I guess there are examples of a few other mydids that "hold out" in small refugia within relatively "development"-impacted habitat. But my impression was that mydids, at least in the western US, tend to live in proximity to sandy habitat.

There are records for Messiasia pertenuis listed in Wilcox & Papavero(1975) as "Tucson, July 1937" and "Sabino Canyon, July 1950" addition to the ones reared from a kangaroo rat nest collected at the Santa Rita Reserve in 1930, and a record from 8 mi. north of Vail in 1962. (Also two more records from Desemboque and Guaymas, Sonora, MX in 1953 and 1965, resp.).

Interestingly, my observation locales for Mydas Flies
can hardly be called 'sandy'. All are areas with riparian or irrigated vegetation. That's true for my observations of mating clusters at Empire Gulch, Santa Cruz River at Ruby Road, Sabino Canyon and at Canada del Oro in Catalina state park: all riparian. The Horse Shoe Canyon one (with Robyn) was in a wide, very rocky wash. I've also seen them in the Canelo Hills south of Patagonia - around ponds. Vail also has Cienega Creek vegetation

Good points, Margarethe!
Thanks for context correction...your right, there's a primarily "riparian" aspect to the locales you mentioned, and overall that's a better way of describing the large-scale habitat for southwestern Mydidae than "sand dunes" :-). For instance the Oak Creek Canyon and Colorado River Mydas posts below are from riparian habitats:


However, at the Colorado River site, there was certainly also significant sandy shore and adjacent flood-plain habitat, and in Oak Creek Cyn probably sandy alluvium substrate available in the vicinity (but no sand dunes! :-).

At any rate, in my comment above I was thinking of the putative association of M. pertenuis with kangaroo rats, whose typical habitat is associated with plenty of sand (and could hardly be called riparian :-).

I also had Rhaphiomidas, Nemomydas, and Pseudonomoneura on the brain from my recent endeavors...and shouldn't have generalized to all Mydidae (which until fairly recently would not have even included Rhaphiomidas). Those genera all have females with the "spiny circlet" terminalia which are believed to be adapted for ovipositing in sandy substrate.

But I think you're right, even for those three genera...the larger scale context of their habitats is more-or-less riparian (i.e. near creeks, or washes...though often dry washes rather than the typical "lush, wet" places the word riparian might bring to mind).

Moved from Mydinae.

I'm not sure, but I'm thinking this is a male: both from what little I can discern of the terminalia...and also from the very narrowly linear shape of what I think is the "bulla".

I think the bulla can be seen in the profile portion of the photo above as a black slit-like mark on the anterior lateral edge of "what appears to be tergite 3". The bulla for M. pertenuis is illustrated in fig. 47 on pg. 56 of Papavero & Wilcox(1)(1971)...and its overall location on the abdomen is indicated in the profile view of fig. 43 on pg. 53 therein.

(Note: I say "what appears to be tergite 3" above because on pg 55 of Papavero & Wilcox(1)(1971), the location of the bullae is described as being on the lateral posterior border of T2...which may actually be the case here, though in the profile image of the photo, it "appears to be" on the anterior lateral margin of T3!)

First BG post for a rare and interesting genus!!
Hi, Margarethe...nice post!! :-)

Though it's been sitting patiently (and relatively unnoticed) under Mydinae for a long time...this turns out to be the first image for a wonderful new genus on the guide!! And, as far as I can tell...except for some images of the disintegrating type specimen (see below)...this is the first good image of this species on the web!!

I've had a hunch this might be Messiasia for a while was the cute little "button-like nose" that first caught my attention and provided the cue/clue that this might be something new and different (i.e. not just some form of Mydas ventralis). But I wanted to "think on it" for a while, see if I might be able to find and figure out more details...and let things "settle in" to a point where I felt more confident I was on the right track.

When I first decided to run this through the Mydidae key in the MND, I was quite intrigued. Because it indeed seemed to go to the unfamiliar sounding genus Messiasia (which at first I was completely unable to pronounce...though of late I've settled on rendering it as "messy-ASS-ee-ah" :-). My initial explorations yielded very little info on this mysterious, new, and difficult to pronounce genus.

But over time I made progress, and once I got a hold of the 1975 revision of Messiasia by Wilcox & Papavero, it keyed very nicely to M. pertenuis....with what seemed to be excellent agreement in terms of descriptions of genus & species, and locality data.

Still, since this was a new and apparently rare & obscure mydid genus for the guide, it took me a while to really become confident I had it right. But I'm pretty confident now :-)

Here are some links of interest:

    1) Type images from the MCZ (collected in 1907...that specimen has seen better days!);
    2) A map of some records...from Torsten Dikow's Asiloidea web site;
    3) An image of the only other congener with range (mostly) in the US...also from Torsten's site.

Interestingly (cf. pg 8 and pg. 34 of Wilcox & Papavero(1975)) 1930, larvae and pupae of M. pertenuis were collected and reared from a kangaroo rat nest on the "Santa Rita Range Reserve" in Pima Co., AZ (a locale familiar to a good number of BugGuider's, due in large part to the efforts of you know who :-). Presumably the larvae were living as commensals in the kangaroo rat nest and had fed on various inquilines there (beetle larvae?)...similar to the way certain species of Mydas have been observed to be associated with ant nests, where they presumably feed on similar inquilines in those situations (perhaps serving as symbionts to the ants...and kangaroo rats? reducing the numbers of beetle larvae and/or other inquilines competing for food resources in the host organism's nests?).

Anyway, I've put more info and links on the genus and species info pages. Great post!

Moved from Mydas Flies.

Moved from ID Request.

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