Tag Archives: Fruit flies

Fantastic Fly Friday, the Anastrepha Fruit Fly

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Drawing of an Anastrepha sp. fruit fly

Today I have a beautiful Fruit Fly (Genus Anastrepha) to show you. I found this specimen when visiting Tulum, Quintana Roo, MX in late January. The place we stay in Tulum has a swimming pool virtually no one ever uses. I love this place so much because I almost always have the pool entirely to myself. Everyone else is at the beach!

Anastrepha fruit fly

However, this particular pool is not maintained so well. More often than not, the filtration system isn’t turned on. I spend the first 15 minutes or so walking around in the pool to skim off all the bugs with a cup I bring from our room.

Unfortunately, my efforts to communicate, in broken Spanish, a request for a pool skimmer to the maintenance workers was a total failure. Probably they secretly referred to me as loco el bicho señora, or something like that. My Spanish is terrible. If you know me well though, finding bugs in the pool is literally one of the reasons I love staying at this place. I have my own vacay niche! Surveying for entomological diversity found in the pool.

There were more than a few bugs for me to “save,” that had landed on the water surface. Some, like this fly, had unfortunately already expired. I skimmed them all out, photographed them, then uploaded my observations onto iNaturalist. I even resuscitated a few that I thought were dead. Toilet paper or tissue paper “beds” work pretty well for drying them out in a pinch.

Fruit fly
Fruit Fly (Anastrepha sp.)

I collected these photographs because I really appreciated the cool picture window patterns on the wings. This is one characteristic of fruit flies. This is also a female specimen as you can see from the longish posterior appendage, her oviscape. Last week, I tried to create a space away from social media to decompress, so I sketched her (to the best of my ability) and used my colored pencils to bring her to life. Probably I did not get all her bristles in the right places. On flies, bristles are diagnostically quite important. I’m not quite there with my artistic rendering, but it was a relaxing activity.

Drawing of an Anastrepha sp. fruit fly
Fruit Fly (Anastrepha sp.)

In spite of their unique and beautiful wing patterns, fruit flies are often considered agricultural pests. Probably they wouldn’t be a pest except that we have these giant industrialized agricultural operations to feed more people than the planet should ever support, and probably, we artificially enable populations of various pests to explode because we are creating extra habitat for them. Fortunately, some targeted biocontrol and Sterile Insect Technique (SIT) has been effective enough to move producers away from utilizing harmful and unsustainable methods of chemical control, although I imagine some operations continue to apply pesticides.

This particular fruit fly is in the Genus Anastrepha. I haven’t really attempted going beyond genus level to identify this one to species. Anastrepha ludens, however, is a name that pops up often in literature from studies in Mexico and California. Anastrepha is a genus in the Family Tephritidae and I believe there are over 200 species of Anastrepha fruit flies in the Americas.

If you are interested in reading more about this genus, I would start off sending you to the 1963 study by Foote and Blanc, referenced below. I am currently waiting on a text I ordered from Abe Books on fruit flies, and will be doing additional reading once it arrives.

One interesting taxonomic tip I can leave you with: Tephritidae are true fruit flies. Those small flies that get into the bananas on your counter or into your rotting compost that many folks refer to as fruit flies aren’t fruit flies at all. They are vinegar or pomace flies, a completely different family called Drosophilidae.

Find out more when you follow me on Fantastic Fly Fridays!

References and Further Reading

Arias OR, Fariña NL, Lopes GN, Uramoto K, Zucchi RA. 2014. Fruit flies of the genus Anastrepha (Diptera: Tephritidae) from some localities of Paraguay: new records, checklist, and illustrated key. J Insect Sci. 1;14:224. doi: 10.1093/jisesa/ieu086. PMID: 25525098; PMCID: PMC5634125.

Baker, A. C. (Arthur Challen). 1944. A Review of studies on the Mexican fruitfly and related Mexican species. Washington, D.C.: U.S. Dept. of Agriculture. https://babel.hathitrust.org/cgi/pt?id=uva.x030450595&seq=3

Bugguide.net. 2026. Anastrepha ludens. Bugguide.net. https://www.bugguide.net/node/view/71452

Greene C. T. 1934. . A revision of the genus Anastrepha based on a study of the wing and on the length of the ovipositor sheath. (Diptera: Tephritidae) . Proc. Entomol. Soc. Wash . 36 : 127 – 179 .

Foote, R. H. and F. L. Blanc. 1963. The Fruit Flies or Tephritidae of California. Bulletin of the California Insect Survey 7: 1-117, 118 figs., 104 maps, colored frontis

Norrbom A. L. 2004. . Anastrepha Schiner (Diptera: Tephritidae) . http://www.sel.barc.usda.gov/Diptera/tephriti/Anastrep/Anastrep.htm .

Stone A. 1942. . The fruit flies of the genus Anastrepha , pp. 112. United States Department of Agriculture, Miscellaneous Publication 439 .

Fantastic Fly Friday

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Chetostoma californicum

Here’s a unique specimen I have to show you. I found this fly on Wednesday after lunch when I went to look for a different species of fly around our above ground pool. I was actually looking for Woodpecker Flies when I found this one. Since I’ve committed to doing a presentation about them for the Scarab Society in September, I’m hoping to observe these weird Woodpecker flies again in the wild and take additional photos and videos to add to what I have collected already.

I didn’t expect to see anything IN the pool. Mostly, I was looking at vertical surfaces, like the sides of the pool and the sides of a nearby tree. When I glanced across the surface of the water, this little one stood out right away. I got a paper bowl to gently scoop it out, expecting it was deceased. It surprised me when it moved just a bit, then wiggled and flipped off the bowl onto the ground.

Chetostoma californicum

I bent down to inspect it, and when I touched it, it flipped around again like a fish out of water. Strange.

I had a plastic cup, so I managed to recapture the fly, wet and bedraggled as it was. I took it back into the house long enough for me to get my other camera. The lighting was better outside, so back out we went.

In case you are wondering, this is one of the Picture Wing Flies in the family Tephrididae. Also known as Fruit Flies. “Picture” references the patterned spots or stripes on the wings. There are other flies, like Drosophila sp., called fruit flies that aren’t actually fruit flies at all. THIS is a true fruit fly.

Many species of fruit flies are known for their pest status, however, there are over 4,300 described species in this family and the great majority of them are not pestiferous at all. They are merely a part of the local, natural ecosystem at large.

I used a key and geographic distribution records to determine the species for this one and believe it to be Chetostoma californicum. Trying to find host plant information led to me to do some deeper digging and to actually order a few more reference books on Tephridid flies. I have another fruit fly specimen I found when we were in Mexico, and plan to share that one with you next Friday. As I learn more about this particular one though, I will update my blog post accordingly.

The reference material I did find about Chetostoma californicum was largely from California and Arizona. Inferring from the documented host plant relationships recorded, it is likely one relationship possible in our immediate area is with native honeysuckle (Lonicera sp.). I also read adults of this species have been collected from Pines (Pinus sp.). We have a Pine tree just next to our above ground pool where the fly was collected.

Geographic distribution records for this fly include Western North America, primarily coastal, down to CA and into Arizona. You can view the GBIF map of reported sightings here – https://www.gbif.org/species/1623842 and also search for observations of the species posted on iNaturalist https://www.inaturalist.org/observations?subview=map&taxon_id=335747

Chetostoma californicum, identified by the oral edge of
bucca (cheek) with a row of about 10 coarse, black bristles with a few finer
black setae at the posterior end of the row. (LeBlanc, 1959)

The only additional personal record I have of this fly on San Juan Island is from February 16, 2024. I would conclude, based on my own observations, that this fly is not particularly an abundant species here. In checking for reports of the species on San Juan, my two posted observations are two of three total for the county.

Now if I can just find out what’s behind the fish flippy behavior…..stay tuned!

Chetostoma californicum (with pollen stuck to it after I accidentally dropped it into a Crocus flower)

Thanks for reading.

References

No author. 2026. Chetostoma californicum. Grokipedia. https://grokipedia.com/page/chetostoma_californicum

Cole, F. 1969. The Flies of Western North America. University of California Press. Berkeley and Los Angeles.

Foote, R.H. and Blanc. F.L. 1963. The Fruit Flies or Tephritidae of California. Bulletin of the California Insect Survey. University of California Press. Berkeley and Los Angeles. https://essig.berkeley.edu/documents/cis/cis07.pdf

LeBlanc, 1959. A new species of Chaetostoma from California (Diptera: Tephritidae). Pan-Pacific Entomologist. 35:201-204. https://biostor.org/reference/225819

Wasbauer MS. 1972. An annotated host catalog of the fruit flies of America north of
Mexico (Diptera: Tephritidae). Occas. Pap. Calif. Dep. Agric. Bur. Entomol. 19:1–172.