Springtime Acmaeodera

Last weekend I mustered up the courage to begin experimenting with the 1-5X macro lens with my new camera. I had played around with it a little, trying to get a feel for finding the subject (it seemed hard) and the working distance (it seemed close). Really though, no amount of fiddling around could take the place of taking it out into the field and using it. I found some ideal subjects to experiment with – springtime Acmaeodera. With more than 150 species, this is one of the largest genera of jewel beetles (family Buprestidae) in North America. This genus is in terrible need of revision – new species continue to be recognized on a regular basis from the desert southwest and Mexico, where the group reaches its greatest diversity. Only a handful of species, however, are found in the eastern part of the U.S.

Acmaeodera_tubulus_IMG_0110_enh2

Photo details: Canon MP-E 65mm macro lens on a Canon EOS 50D, ISO 100, 1/200 sec, f/11, MT-24EX flash 1/8 power through diffuser caps

One of the most abundant and widespread of these is Acmaeodera tubulus (first two photos). Measuring only 5-7mm in length, it is among the smallest members of the genus and can be recognized by its black color with bronzy sheen and 8 (usually) small, yellow spots forming two longitudinal rows on each elytron. Adults of this species feed on the petals of a great variety of flowers – this individual was feeding on the petals of eastern beebalm (Monarda bradburiana). The larvae of this species are wood borers in twigs and small branches of various hardwood trees – I myself have reared it from dead branches of green hawthorn (Crataegus viridis), several species of hickory (Carya spp.), hackberry (Celtis occidentalis), honey locust (Gleditsia triacanthos), walnut (Juglans nigra), eastern hophornbeam (Ostrya virginiana), willow (Salix sp.), and slippery elm (Ulmus rubra).

Acmaeodera_tubulus_IMG_0123_enh2

Photo details: Canon MP-E 65mm macro lens on a Canon EOS 50D, ISO 100, 1/200 sec, f/11, MT-24EX flash 1/8 power through diffuser caps

While not apparent from these photos, adults in flight have the appearance of small bees. The elytra of all Acmaeodera are fused and do not separate during flight as in most other beetles, which in this small species results in a profile during flight similar to that of a small halictid (sweat bee). There is another species in Missouri (A. neglecta) that closely resembles A. tubulus but which can be distinguished by its larger punctures, duller surface, and the yellow spots of the elytra often longitudinally coalesced into irregular “C”-shaped markings on each side. Acmaeodera neglecta occurs primarily in the south-central U.S., and in Missouri I have found it most often in glade habitats.

Acmaeodera_ornata_IMG_0155_enh2

Photo details: Canon EF 100mm macro lens on a Canon EOS 50D, ISO 100, 1/200 sec, f/11, MT-24EX flash 1/8 power through diffuser caps

Another common (though much less so than A. tubulus), springtime Acmaeodera in the eastern U.S. is Acmaeodera ornata (last photo). This handsome species is distinctly larger than A. tubulus, usually around 8-11mm in length, and has a broader, more flattened appearance with a distinct triangular depression on the pronotum. The elytra have a bluish cast rather than the bronzy sheen of A. tubulus, and the spots on the elytra are smaller, more numerous, and more of a creamy rather than yellow color. No other species in the eastern U.S. can be confused with it, although there is a very similar species (A. ornatoides) that occurs in Oklahoma and Texas.

This species, too, is fond of a great variety of flowers – especially asteraceous species, with this individual photographed on the widespread (but unfortunately exotic) ox-eye daisy (Leucanthemum vulgare). The body is covered with numerous long, thin hairs which may function in pollination – enlarge the photo to see the large amount of pollen that has become trapped among the hairs of this individual. Despite its widespread occurrence across the eatern U.S., larval host records are almost non-existent for this species – limited to some very old (and not entirely reliable) reports of it breeding in hickory and black locust (Robinina pseudoacacia). I have not managed to rear this species yet, despite the large number of rearings I’ve done from a wide variety of woody species in Missouri.

Copyright © Ted C. MacRae 2009

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About Ted C. MacRae

Ted C. MacRae is a research entomologist by vocation and beetle taxonomist by avocation. Areas of expertise in the latter include worldwide jewel beetles (Buprestidae) and North American longhorned beetles (Cerambycidae). More recent work has focused on North American tiger beetles (Cicindelidae) and their distribution, ecology, and conservation.
This entry was posted in Buprestidae, Coleoptera and tagged , , , , , , . Bookmark the permalink.

12 Responses to Springtime Acmaeodera

  1. Art Evans says:

    Nice photos and article!

  2. Marvin says:

    Wow, the accumulated pollen shows up well in the enlarged photo. Great work, Ted.

  3. cicindela says:

    Very nice – looks like you are getting the hang of the 1-5x lens

    • Hi Chris – thanks, getting better but I don’t know if I’m ready to say I’ve got the hang of the 1-5x yet since these were among the first shots I took with it. I did learn from using the 100mm the previous weekend that I needed to cut the flash power, and adding diffuser caps seemed like a good idea – I think those two things made a big improvement. I still need to get better at holding the 1-5x steady while I’m shooting, and also get a better feel for flash power and f-stops at higher mags.

      Still, I like these – especially the two Acm. tubulus photos. Depth-of-field could have been a little better is about it.

  4. Moe says:

    I really want that MP-E65mm lens! The photos look great.

  5. James C. Trager says:

    Thanks for this posting, Ted. I took some pictures of these (I think) recently, not quite as good as yours. But I’ll send you copies to judge for yourself and confirm the ID; Okay?

  6. Roger Fuester says:

    What kind of containers do you use for rearing out buprestids? I have been using ventilated trash cans.
    Roger

    • Hi Roger – I use fiber drums of various sizes, but I think ventilated trash cans will work fine as long as they are sealed well to prevent escapes. Metal cans work well also. The only thing I’ve used in the past that did not work well were non-ventilated plastic buckets – they tended to condensation, which is death to the beetles due to fungal growth.

      I don’t do as much rearing these days as I used to – at one point several years ago I had 100+ drums going at once. It took several hours a week to go through them all during the spring and summer!

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