{"id":11982,"date":"2021-01-07T16:10:02","date_gmt":"2021-01-07T22:10:02","guid":{"rendered":"https:\/\/uwm.edu\/field-station\/?p=11982"},"modified":"2024-12-26T15:14:35","modified_gmt":"2024-12-26T21:14:35","slug":"procecidochares-atra-fruit-fly","status":"publish","type":"post","link":"https:\/\/uwm.edu\/field-station\/bug-of-the-week\/procecidochares-atra-fruit-fly\/","title":{"rendered":"Procecidochares Atra Fruit Fly"},"content":{"rendered":"\n

Greetings, BugFans,<\/p>\n\n\n\n

The story of this fly (whose name is considerably longer than the fly itself) demonstrates why the BugLady loves BOTW. Could she dig up a lot of details about how this little beauty lives its life? She could not. But she found two interesting side stories about it.<\/p>\n\n\n\n

As always, our first episode of the New Year is vocabulary-rich.<\/p>\n\n\n\n

\"Fruit<\/a><\/figure>\n\n\n\n

Procecidochares atra<\/em> is a true fruit fly in the family Tephritidae<\/em> \u2014not one of those red-eyed, flying lab rats that circle your bowl of grapes in summer, or that escape from confinement and live in labs in perpetuity. Those are more properly called Pomace or Vinegar flies, family Drosophilidae<\/em>. Because of the simplicity of their DNA and the ease in raising them, some Drosophila are extraordinarily well-studied and experimented on.<\/p>\n\n\n\n

Fun Drosophila<\/em> Fact: according to Wikipedia, if a female Drosophila melanogaster sees a female larva of an endoparasitic wasp, she will start laying her eggs on rotting fruit or some other alcoholic substrate. Why? Because her offspring will imbibe it, and wasps have a low tolerance for alcohol.<\/p>\n\n\n\n

But we digress.<\/p>\n\n\n\n

\"Fruit<\/a><\/figure>\n\n\n\n

Tephritid<\/em> flies are also called Picture-winged flies and Peacock flies, but those names are more properly applied to other tiny flies. Those fancy wing patterns are used both in courtship and in defense (more about that in a sec). Wikipedia says that the females use their telescopic ovipositors to insert their eggs in living plant material. The larvae of most species are vegetarians, they feed on plant tissue that the eggs are deposited in, or like the genus Procecidochares<\/em>, they make a gall<\/a> <\/i> and feed, and finally pupate inside it<\/a> <\/i>. Some family members are food specialists while others enjoy a more varied menu; some are agricultural pests, and others help to control agricultural pests. Adults feed blamelessly on nectar, pollen, honeydew, and decaying vegetation.<\/p>\n\n\n\n

There are about 15 species in the genus Procecidochares<\/em> in North America, all of which are gall-makers on goldenrods, and Procecidochares atra<\/em> (no common name), found from the Atlantic to the Great Plains, is one of the larger and more common species<\/a> <\/i>. Procecidochares atra<\/em> has been recorded on three species of goldenrod.<\/p>\n\n\n\n

Interesting Side Story Number 1 (and vocabulary challenge):<\/h3>\n\n\n\n

Most, but not all, genus members are univoltine (one generation per year), but Procecidochares atra<\/em> is bivoltine (two generations). The spring generation forms a stem gall near the base of an emerging goldenrod, and that gall is polythalamous<\/em> (containing multiple larvae, as many as 21). Galls of the late-summer generation are formed above mid-stem, often on the buds<\/a> <\/i>, and are monothalamous<\/em> (each houses a single larva). The galls are leafy rosettes. The photographer of this gall<\/a> <\/i> bagged it to see what kind of fly would emerge and got wasps instead \u2013 the wasps had probably parasitized the larva of the gall-making fly (unless they were inquilines). It\u2019s probable that the adults overwinter and lay eggs as goldenrod starts to grow in spring.<\/p>\n\n\n\n

But, as author Isaac Asimov once wrote, “The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but, ‘That’s funny\u2026.'”<\/em>  Researchers Phillips and Smith studied Procecidochares atra<\/em>, noting the seasonal and structural differences in its gall making habits and identifying two new host species, Canada goldenrod and horseweed (Erigeron canadensis<\/em>). To complicate things even more, the late summer gall they found on horseweed was a stem gall located inches from the ground, not a bud gall.<\/p>\n\n\n\n

What\u2019s going on? The researchers suspected that they might be dealing with what is called a \u201ccryptic species,\u201d\u2014a described species that\u2019s actually made up of several distinct species that don\u2019t interbreed but that look (to us) identical. This would explain the differences in hosts and seasons and gall formation. Although (using the tools available in the 1990\u2019s) they were \u201cunable to differentiate this specimen [on Erigeron<\/em>] morphologically from other specimens of Procecidochares atra<\/em>,\u201d they didn\u2019t rule out the potential for two or more cryptic species, separating the spring, fall, and Erigeron gall makers. And, of course, they noted that there needed to be a \u201csystematic revision of the genus.\u201d<\/p>\n\n\n\n

Interesting side story Number 2:<\/h3>\n\n\n\n

Yes, males use their patterned wings like semaphore flags in courtship, to signal to females, but tephritids also use them in defense. In its write-up about the family Tephritidae<\/em>, bugguide.net <\/a> <\/i>says<\/p>\n\n\n\n