Webinar Title: Flies and Wasps (Great Southeast Pollinator Course, Week 6)
Webinar Date: July 21, 2026
Speakers: Dr. Jason Schmidt, Associate Professor, University of Georgia (Tifton campus); Dr. Scott Clem, Assistant Professor of Insect Ecology, Illinois State University; Gabrielle LaTora, Agriculture and Natural Resources Agent, UGA Extension, Fulton County
Moderator: Becky Griffin, UGA Extension, course host
Duration: 1:20:45
Series: Great Southeast Pollinator Course
CEU Categories: None. No applicator CEU applies to this course. Educators who attended the live session earn 1 PLU.
NARRATIVE SUMMARY
Week 6 ran with three presenters. Dr. Jason Schmidt, associate professor at UGA’s Tifton campus, opened on biodiversity: his lab takes soil and field samples, runs DNA extraction and PCR, and resolves which species are present, whose pollen is on which pollinator, and what is eating what. He showed habitat plantings with solar producers, blueberry growers, and Mercier Orchards. From the Insect Atlas he pulled two numbers: roughly 90% of animal species are insects, and pollinator richness tracks with pollination success. The same pattern holds for natural enemies and pest control. Then he made diversity concrete. Georgia’s lady beetles run down to two millimeters. A Geocoris punctipes nymph cannot fly or reproduce until its last molt.
Dr. Scott Clem, assistant professor of insect ecology at Illinois State University, gave the field rule first: count the wings. Two wings, large eyes, short antennae, and no pollen basket means a fly. He covered five fly groups: the midges that pollinate cacao and carry a $120 billion chocolate industry, bee flies and the inch-and-a-half mydas fly out in July, blow and flesh flies drawn to pawpaw flowers that growers bait with “stink stations,” thick-headed flies that parasitize bumblebees, and hoverflies. Syrphine hoverfly larvae eat several hundred aphids apiece; eristalines, about 65% of species, develop in dead wood and water-filled tree holes. Flies visit at least 72% of the world’s crops. Clem has found 158 hoverfly species in Georgia and expects the real count past 200, and he named mountain mint, Virginia pepperweed, smartweeds, asters, and blue mistflower as fly-friendly natives.
Gabrielle LaTora, ANR agent for UGA Extension in Fulton County, closed on wasps: the constricted waist (the petiole), a smooth hairless body, long thread-like antennae, four hooked wings, and a hammerhead-shaped head with small eyes at the ends, set against a fly’s dome-shaped head, “pancake eyes,” and two stubby antennae rising between them. The ovipositor doubles as the stinger, so anything that stings is female. Social wasps are a small fraction of species, mostly vespids, and the only aggressive ones; the solitary majority paralyze prey, lay one egg, seal the cell, and leave. Parasitoids account for 60 to 80% of wasp species, and their hosts die. Her advice to gardeners: leave a hornworm covered in Cotesia congregata cocoons alone. Those are pupae, and 30 or 40 wasps will emerge hunting more hornworms.
YOUTUBE TIMESTAMPS
0:00 Welcome and introduction to Dr. Jason Schmidt
0:56 Schmidt: how the Tifton lab studies food webs
2:52 Habitat work with solar, blueberry, and apple growers
5:32 The Insect Atlas: 90% of animal species are insects
8:43 Georgia’s lady beetles, down to two millimeters
9:30 Life-stage diversity in Geocoris punctipes
11:00 Mouthparts and function, from vespids to ants
13:48 Super flyers, dragonfly eyes, and wing venation
15:52 Micro air vehicles built from insect wings
17:42 Q&A: where to get the pollinator.org posters
18:33 Introduction to Dr. Scott Clem
19:54 Clem: confessions of a dipterist
20:59 What is a fly? Count the wings
23:02 Myophily: fly pollination defined
24:15 When flies fly: cool hours, shade, spring and fall
26:26 What fly larvae do for a living
28:45 Group 1: Nematocera, midges and mosquitoes
31:25 Midges pollinate cacao: a $120 billion industry
31:52 Group 2: lower Brachycera and the bee flies
34:38 Group 3: calyptrates, blow flies and flesh flies
35:53 Pawpaws and the grower’s “stink station”
37:55 Group 4: acalyptrates and thick-headed flies
40:07 Group 5: hoverflies, the flying eyeballs
41:14 Syrphinae larvae and the aphids they eat
42:58 Eristalinae: 65% of species, born in dead wood
45:46 Why leaving dead wood matters
46:29 Hoverfly migration and Georgia’s 158 species
49:57 Flies visit 72% of the world’s crops
50:55 Fly-friendly native plants for your yard
52:04 Clem’s book chapter and QR codes
53:06 Introduction to Gabrielle LaTora
54:23 Fulton County census counts on August 22
55:47 Classifying wasps: Hymenoptera and Apocrita
56:36 The narrow waist and what a petiole is
58:56 Ovipositors, and why a stinger means female
1:00:40 Social wasps, castes, and defending the nest
1:02:45 Solitary wasps: the vast majority
1:03:52 How a solitary female provisions her nest
1:05:30 Nest types: burrows, mud pots, and plant stems
1:06:18 Predators versus parasitoids
1:09:19 Cotesia congregata and the tomato hornworm
1:10:32 Why to leave a cocoon-covered hornworm alone
1:10:54 Why wasps visit flowers at all
1:12:29 Wasp versus fly: the side-by-side comparison
1:14:57 Q&A: sterile workers and the sting as defense
1:16:35 Do parasitized hornworms keep feeding?
1:18:08 Hornets, hooked wings, and where pollen sticks
1:19:29 A small nest with no larvae in sight
1:20:21 Closing thanks
QUESTIONS & ANSWERS
Q: I’m on a flower during the census and I have five seconds. Fly or wasp?
A: Count the wings. Clem’s rule is that flies have two wings and bees and wasps have four. Flies also have very large eyes, short antennae, and no scopa, the pollen-collecting basket you see loaded on a bee’s hind leg. LaTora noted that four wings are hard to see in the field because wasps hook their front and hind wings together, so she treats wing count as a secondary character.
Q: If I can’t see the wings, what else works?
A: Look at the head. LaTora described a fly’s head as a semicircular dome with “pancake eyes” covering most of it, and two short stubby antennae arising from the middle of the head between the eyes, often with a little club and a single bristle. A wasp’s head she described as hammerhead-shark shaped, elongated horizontally with small eyes out toward the ends. Wasps also have a smooth, mostly hairless, slender body and long, straight, thread-like antennae.
Q: Do flies actually pollinate anything I care about?
A: Clem said flies visit at least 72% of the world’s crops, and in some cases they matter more than bees. In the Southeast he listed canola, carrots, strawberries, blackberries, apples, peaches, onions, peppers, and kiwi as crops that get some level of fly pollination. His headline example was cacao, which is pollinated primarily by two-to-three-millimeter midges, a roughly $120 billion chocolate industry riding on them.
Q: When should I go out looking for flies?
A: Mornings or late afternoon rather than the heat of the day. Clem said flies tend to be active during cooler times, forage more in the shade, and turn up in greater abundance during spring and fall, when several species come out in numbers.
Q: What should I plant to bring flies into my yard?
A: Clem’s list of fly-friendly natives was mountain mint, Virginia pepperweed, smartweeds, various asters (pink, white, and blue), and blue mistflower. Mountain mint was his first pick; he checks his mother’s large mountain mint plant every time he goes home because of what shows up on it. Virginia pepperweed and smartweeds have tiny flowers and little visual appeal, but he said flies work them heavily.
Q: Are hoverflies doing anything besides visiting flowers?
A: The subfamily Syrphinae has predaceous larvae that feed on aphids. Clem described the larvae as little slugs that crawl around, grab an aphid, slice into it, and suck the juices out: several hundred aphids over a single larva’s lifetime. That makes a population of them worth having for aphid control on top of the pollination.
Q: Why does leaving dead wood in the yard help pollinators?
A: About 65% of hoverfly species fall in the subfamily Eristalinae, and their larvae feed on dead and decaying material. Clem said they live in dead wood and in tree holes, the water-filled cavities where rat-tailed maggots breathe through a long siphon. Clear out all the dead and decaying wood, he said, and you lose the habitat those pollinating hoverflies need.
Q: Everything that stings me is female? How does that work?
A: The ovipositor is the egg-laying organ that only female insects have, and in wasps it does dual duty as the stinger. LaTora’s point: when a yellowjacket or paper wasp stings you, it is always a female, because she is stinging you with her ovipositor. The same holds for bees.
Q: Which wasps do I actually need to worry about?
A: The social ones, and they are a small fraction of all wasp species; mostly vespids, including yellowjackets and paper wasps. LaTora explained they get aggressive when they feel the nest is threatened because a whole colony has a lot at stake. Solitary wasps are the vast majority, and the ones you will mostly see on flowers during the census. They do not defend a nest and will only sting if they get squeezed, into an armpit or under an arm on a chair.
Q: What’s the difference between a parasitoid and a parasite?
A: The host dies. LaTora defined a parasitoid as an insect that develops in or on another insect, and the distinction from a parasite is that the parasitoid’s host dies in the process. Between 60 and 80% of wasp species live this way, and most target a single host species or a small group of closely related ones.
Q: I found a hornworm covered in little cocoons. Should I kill it?
A: Leave it alone. Those are the pupae of Cotesia congregata, a parasitoid wasp whose larvae fed inside the caterpillar and tunneled out to pupate. LaTora said the caterpillar does not have much time left; it slows down, and you can see necrotic patches on it. You get 30 or 40 new wasps that are not dangerous and are out looking for more hornworms. If the feeding damage still bothers you, pick the caterpillar off and set it in a wooded area.
Q: Why are wasps on my flowers if they hunt insects?
A: The adults are not eating the prey; they carry it back to the nest for the larvae. Adult wasps stop at flowers for sugar: nectar, plant sap, and honeydew, which LaTora called our euphemism for bug poop. She described it as insect Red Bull, the carbohydrate that fuels a female’s hunting flights. Pollen sticks to the body, legs, and mouthparts along the way, so wasps pollinate incidentally, but without much hair they are not efficient at it even though they visit a lot of flowers.
ADDITIONAL RESOURCES
Named on-air during the session:
- Common Hoverflies of Georgia: Dr. Scott Clem’s recently published guide, shared by QR code during the talk; he noted it covers most surrounding southeastern states as well.
- Field Guide to the Flower Flies of Northeastern North America: Clem’s recommended identification guide; no southeastern equivalent exists, but he said it largely covers southeastern species.
- “The Unsung Heroes: The Importance of Flies in Wild and Domesticated Pollination”: Clem’s forthcoming book chapter in Threats to Pollinator Abundance and Diversity, expected before the end of 2026.
- Dr. Clem’s lab, Illinois State University: QR code shared at the close of his talk.
- Pollinator Partnership (pollinator.org): source of the regional pollinator posters Schmidt showed. He said they are free to download, released roughly annually, and that the organization supplied him a large-format file on request.
- The Insect Atlas: the book Schmidt drew his biodiversity figures from.
- Fulton County Extension: contact them for the Great Southeast Pollinator Census counting events LaTora’s Master Gardener volunteers are hosting on Saturday, August 22, 2026.
- Georgia Museum of Natural History, Athens: the collection Clem worked through for the Georgia hoverfly biodiversity project.
Processed for UGA Center for Urban Agriculture / Great Southeast Pollinator Course · gsepc.org
Source: Corrected SRT (Stage 1), file GTBOP_Transcript_2026-07-21_FliesAndWasps.srt (282 blocks)