Welcome to Hexapodcast
See below for some literature cited for each episode.
Episodes:
Season 2, Episode 3 – Tom Waits, THE FLY, part 2 with Christian Conners. John and Lee are joined again by Christian to dissect the fly. Lots of fun fly facts and diversity here. You’re gonna love it.
Season 2, Episode 2 – Tom WAits, THE FLY, with guest Christian Conners. Stireman and Dyer are joined by special guest Christian Conners to celebrate the entomologist and singer-songwriter, Tom Waits. We dissect his brilliant song, “The Fly.”
Season 2, Episode 1 — Insect Declines with Guest Dr. Chris Halsch. John and Lee talk to Chris about his work on butterfly declines and discuss: 1. definition of insect declines; 2. history of “insect decline” as a major subdiscipline; 3. causes of declines. Plus: the trolly problem, a short clip from a Dolly Parton butterfly duet, an annoying fly, and some really silly jokes.
Season 1, Episode 9 — FORENSIC entomology. Dyer describes finding flies around a body he found in the street then discusses forensic entomology with Stireman, who studies flies. We could definitely do a sequel on this one….
Season 1, Episode 8 — Hexapod SEX. This episode is all about insect sex with a lot of inappropriate and cringe-worthy jokes, music, and other fails. It is probably worth listening to and it is definitely fact-based… just silly.
Season 1, Episode 7 — Bark Beetles Part 2! Fun, fun, fun discussions with Dr. Amy Trowbridge about bark beetles and so much more. Part 2. There may be some good jokes and a few political comments in this episode.
Season 1, Episode 6 — Bark beeetles with Amy Trowbridge… Part 1. A hilarious episode in which Dr. Trowbridge tells us all about bark beetles, the forests they are affecting, and some chemical ecology. Dyer and Stireman pitch in a few facts about insect brains.
Season 1, Episode 5 — Tales from the Trachae. How do insects breathe and other horror stories. This is a pretty good episode.
Season 1, Episode 4 — Insect Digestion with Lora Richards. A light discussion about guts, sequestration, spitting, pooping, vomit, and other dinner-time conversations.
Season 1, Episode 3 — Insect Diversity with Matt Forister. How many species are there? What are we losing in the Anthropocene? What is the Journal of Lost Species? We may have some answers here.
Season 1, Episode 2 — Insect systematics. Unless you love insects and systematics, this episode might be “the most boring podcast in history” – according to Stireman.
Season 1, Episode 1 — Introduction. How does one become an entomologist? Why study entomology? A very brief introduction to our podcast.
Links to listening platforms:
Spotify: https://open.spotify.com/show/3Tm9Odavg7wwYehAe8jB6Q
Apple podcasts: https://podcasts.apple.com/us/podcast/hexapodcast/id6803601398?uo=4
grepfm: https://grep.fm/podcasts/hexapodcast/
youtube (not all episodes are available on youtube): https://youtube.com/playlist?list=OLTWcdkRr3TgMV6t15X4g_rYANKLfDUeTKg&si=NAeVDkf72icdzrw4
Some literature cited for each episode:
Season 2, Episodes 2–3 — Tom Waits, The Fly, Parts 1 & 2
Raguso, R.A. 2020. Don’t forget the flies: dipteran diversity and its consequences for floral ecology and evolution. Applied Entomology and Zoology 55: 1–7.
A particularly good broad Diptera paper: flies occupy an extraordinary range of ecological niches and include important generalized and highly specialized pollinators. The review is also a nice corrective to our tendency to think first about bees when discussing insect pollination: Diptera includes everything from generalized syrphid pollinators to highly specialized relationships involving fungus gnats, carrion flies, and long-tongued flies.
Wiegmann, B.M. et al. 2011. Episodic radiations in the fly tree of life. Proceedings of the National Academy of Sciences 108: 5690–5695.
A phylogenetic overview of the evolutionary history and remarkable diversification of Diptera.
Hanna, L. et al. 2023. Evaluating old truths: Final adult size in holometabolous insects is set by the end of larval development. Journal of Experimental Zoology Part B: Molecular and Developmental Evolution 340: 270–276.
A fun general insect fact with a strong Diptera connection: experiments with Drosophila and representatives of the other major holometabolous orders confirm that final adult size is established by the end of larval development and that adults do not subsequently grow.
Winding, M. et al. 2023. The connectome of an insect brain. Science 379: eadd9330.
An extraordinary reconstruction of the complete larval Drosophila brain: 3,016 neurons and roughly 548,000 synapses. Beyond being an impressive technical achievement, the connectome reveals extensive multisensory integration and recurrent neural circuitry involved in learning and action selection.
Season 2, Episode 1 — Insect Declines with Chris Halsch
Wagner, D.L. 2020. Insect declines in the Anthropocene. Annual Review of Entomology 65: 457–480.
A broad introduction to the evidence for insect declines and the multiple global-change drivers behind them, including habitat loss, climate change, pesticides, invasive species and artificial light.
Halsch, C.A. et al. 2021. Insects and recent climate change. Proceedings of the National Academy of Sciences 118: e2002543117.
A useful synthesis of the many ways climate change can affect insects, emphasizing that responses depend on species biology, geography and interactions with other environmental changes.
Fabian, S.T., Sondhi, Y., Allen, P.E., Theobald, J.C. & Lin, H.-T. 2024. Why flying insects gather at artificial light. Nature Communications 15: 689.
A particularly elegant mechanistic study of one increasingly important global-change driver. Three-dimensional flight experiments show that insects do not simply steer toward artificial lights. Instead, they orient their dorsal surface toward the light, apparently misapplying a normal orientation response in which the brightest part of the visual field indicates the sky. The result can be orbiting, stalling, inversion and entrapment around artificial lights.
Season 1, Episode 9 — Forensic Entomology
Amendt, J., Krettek, R. & Zehner, R. 2004. Forensic entomology. Naturwissenschaften 91: 51–65.
A good introduction to the biological basis of forensic entomology and the use of insect development and succession in estimating postmortem intervals.
Tomberlin, J.K. et al. 2011. Basic research in evolution and ecology enhances forensics. Trends in Ecology & Evolution 26: 53–55.
An especially useful paper for students because it connects forensic entomology back to basic ecological and evolutionary questions rather than treating it simply as an applied identification technique.
Season 1, Episode 8 — Hexapod SEX
Gwynne, D.T. 2008. Sexual conflict over nuptial gifts in insects. Annual Review of Entomology 53: 83–101.
Nuptial gifts provide wonderful examples of the sometimes overlapping interests—and sometimes very different interests—of males and females during mating.
Tatarnic, N.J., Cassis, G. & Siva-Jothy, M.T. 2014. Traumatic insemination in terrestrial arthropods. Annual Review of Entomology 59: 245–261.
An overview of one of the stranger outcomes of sexual selection and sexual conflict: mating systems in which sperm is introduced by wounding the female rather than through the conventional reproductive tract.
Season 1, Episodes 6–7 — Bark Beetles with Amy Trowbridge
Raffa, K.F., Grégoire, J.-C. & Lindgren, B.S. 2015. Natural history and ecology of bark beetles. In Vega, F.E. & Hofstetter, R.W. (eds.), Bark Beetles: Biology and Ecology of Native and Invasive Species. Academic Press.
A broad treatment of the natural history of bark beetles and the ecological processes that allow tiny insects to have enormous effects on forests.
Trowbridge, A.M. & Stoy, P.C. 2013. BVOC-mediated plant–herbivore interactions. Current Opinion in Plant Biology 16: 434–440.
A useful introduction to biogenic volatile organic compounds and the chemical conversations among plants, herbivores and their environment.
Stöckl, A.L. & Heinze, S. 2015. A clearer view of the insect brain—combining bleaching with standard whole-mount immunocytochemistry allows confocal imaging of pigment-covered brain areas for 3D reconstruction. Frontiers in Neuroanatomy 9: 121.
A nice methodological paper showing how modern insect neuroanatomists actually visualize and reconstruct brains. Chemical bleaching allows normally pigment-obscured structures to be imaged with confocal microscopy and incorporated into three-dimensional brain reconstructions.
Season 1, Episode 5 — Tales from the Tracheae
Chown, S.L., Gibbs, A.G., Hetz, S.K., Klok, C.J., Lighton, J.R.B. & Marais, E. 2006. Discontinuous gas exchange in insects: A clarification of hypotheses and approaches. Physiological and Biochemical Zoology 79: 333–343.
Insect respiration is considerably more interesting than simply “air enters the spiracles.” This paper examines discontinuous gas-exchange cycles and the competing hypotheses for why insects periodically close and open their spiracles.
Harrison, J.F., Woods, H.A. & Roberts, S.P. 2012. Ecological and Environmental Physiology of Insects. Oxford University Press.
A broader physiological treatment that places insect respiration in the context of body size, temperature, water balance, energetics and environmental constraints.
Mantziaris, C., Bockemühl, T. & Büschges, A. 2020. Central pattern generating networks in insect locomotion. Developmental Neurobiology 80: 16–30.
Useful where we cross from respiration into movement: central pattern generators are neural circuits capable of generating rhythmic motor output, and insects provide classic examples involving flight, walking and crawling. The paper also emphasizes that functional movement emerges from interaction among central circuits, sensory feedback and coordinating pathways.
Season 1, Episode 4 — Insect Digestion with Lora Richards
Khan, S.A., Kojour, M.A.M. & Han, Y.S. 2023. Recent trends in insect gut immunity. Frontiers in Immunology 14: 1272143.
Probably the best general paper for this topic. It covers foregut, midgut and hindgut organization, the peritrophic matrix, microbiota, gut immunity and physiological compartmentalization. It is particularly useful for emphasizing that the insect gut is simultaneously a digestive organ, an interface with microorganisms and toxins, and an important component of the immune system.
Godoy, R.S.M., Barbosa, R.C., Huang, W., Secundino, N.F.C., Pimenta, P.F.P., Jacobs-Lorena, M. & Martins, G.F. 2023. The larval midgut of Anopheles, Aedes, and Toxorhynchites mosquitoes (Diptera, Culicidae): a comparative approach in morphophysiology and evolution. Cell and Tissue Research 393: 297–320.
An excellent comparative example of how radically different diets—including detritivory and predation—are reflected in insect gut morphology and physiology. The comparison also highlights gastric caeca, the peritrophic matrix, enterocytes and enteroendocrine cells rather than treating the midgut as simply a digestive tube.
Chen, L., Liu, M., Di Giulio, A., Chen, X., Sabatelli, S., Wang, W. & Audisio, P. 2023. Morphological study of the alimentary canal and Malpighian tubules in the adult of the pollen beetle Meligethes (Odonthogethes) chinensis (Coleoptera: Nitidulidae: Meligethinae). Insects 14: 298.
A wonderfully concrete anatomical complement to the broader gut papers. This pollen-feeding beetle has the standard foregut–midgut–hindgut organization but with some striking specializations: no crop, numerous gastric caeca, a coiled anterior hindgut and six Malpighian tubules forming a cryptonephridial system.
Season 1, Episode 3 — Insect Diversity with Matt Forister
Stork, N.E. 2018. How many species of insects and other terrestrial arthropods are there on Earth? Annual Review of Entomology 63: 31–45.
This addresses the simple but extraordinarily difficult question: how many insect species are there? It also illustrates why estimates depend so strongly on sampling, geographic scaling, host specificity and assumptions about poorly known groups.
Seymour, M. et al. 2024. Global arthropod beta-diversity is spatially and temporally structured by latitude. Communications Biology 7: 552.
A modern large-scale look at arthropod diversity that shifts attention from simply counting species to understanding how community composition changes across space and time.
Forister, M.L. et al. 2019. The global distribution of diet breadth in insect herbivores. Proceedings of the National Academy of Sciences 116: 442–447.
An important reminder that insect diversity is inseparable from interaction diversity. Herbivorous insects vary enormously in diet breadth, and specialization on host plants has long been central to hypotheses about why insects are so diverse.
Hafer-Hahmann, N. & Vorburger, C. 2024. Parasitoid species diversity has no effect on protective symbiont diversity in experimental host-parasitoid populations. Ecology and Evolution 14: e11090.
This extends the diversity question inside the insects themselves. Aphids can carry heritable bacterial symbionts such as Hamiltonella defensa that protect them against parasitoid wasps. The experiment asks whether diversity at one trophic level helps maintain diversity at another—and finds surprisingly little evidence that parasitoid species diversity maintains symbiont diversity. It is a good example of diversity operating simultaneously among species, within species and within individual insects.
Colazza, S., Peri, E. & Cusumano, A. 2023. Chemical ecology of floral resources in conservation biological control. Annual Review of Entomology 68: 13–29.
Another useful expansion of what we mean by insect diversity. Flowers provide resources not only to pollinators but also to parasitoids and even hyperparasitoids, and floral volatiles and nectar-associated microorganisms help determine who finds and uses those resources. It is a particularly nice example of diversity embedded within multitrophic interaction networks.
Christensen, T., Dyer, L.A., Forister, M.L., Bowers, M.D., Carper, A., Teglas, M.B., Hurtado, P. & Smilanich, A.M. 2024. Host plant-mediation of viral transmission and its consequences for a native butterfly. Ecology: e4282.
This one connects particularly well to Matt Forister and to the idea that insect diversity cannot be understood independently of ecological interactions. In Baltimore checkerspots, Euphydryas phaeton, host-plant identity affected survival and horizontal transmission of a densovirus, while greater sequestration of plant secondary compounds was associated with lower viral loads. Thus host expansion can alter not only an herbivore’s diet but its interactions with natural enemies.
Season 1, Episode 2 — Insect Systematics
Misof, B. et al. 2014. Phylogenomics resolves the timing and pattern of insect evolution. Science 346: 763–767.
A landmark attempt to reconstruct the deep evolutionary history of insects using genome-scale sequence data.
Kjer, K.M., Simon, C., Yavorskaya, M. & Beutel, R.G. 2016. Progress, pitfalls and parallel universes: a history of insect phylogenetics. Journal of the Royal Society Interface 13: 20160363.
This is a particularly nice pair pedagogically: Misof et al. represents modern phylogenomics, while Kjer et al. explains how insect systematics moved through morphology and early molecular approaches into genome-scale phylogenetics.
Ehrlich, P.R. & Raven, P.H. 1964. Butterflies and plants: A study in coevolution. Evolution 18: 586–608.
Although this is primarily a coevolution paper, it is also an instructive historical example of how systematists used relationships among groups of butterflies and their host plants to make evolutionary arguments long before genomic phylogenies were available. Their central insight was that insect relationships, plant relationships and patterns of host use contain overlapping—but not identical—information about evolutionary history.
Season 1, Episode 1 — Introduction: Why Study Entomology?
Ehrlich, P.R. & Raven, P.H. 1964. Butterflies and plants: A study in coevolution. Evolution 18: 586–608.
Still one of the classic demonstrations of why insects have been so important to evolutionary ecology. Ehrlich and Raven explicitly used butterflies and their host plants as a model for understanding the evolution of ecological interactions and biological diversification. Their emphasis on plant secondary chemistry as both a barrier to most insects and a host-recognition cue for specialists remains remarkably recognizable sixty years later.
Winding, M. et al. 2023. The connectome of an insect brain. Science 379: eadd9330.
At the other end of the historical spectrum: an entire insect brain reconstructed at synaptic resolution. The study mapped 3,016 neurons and approximately 548,000 synapses, providing an extraordinary demonstration of how insects can be used to ask fundamental questions about nervous-system organization, sensory integration, learning and behavior.
Colazza, S., Peri, E. & Cusumano, A. 2023. Chemical ecology of floral resources in conservation biological control. Annual Review of Entomology 68: 13–29.
For the question is “why study insects?” this is a good illustration of how quickly the answer expands from individual organisms to entire ecological networks: plants produce floral odors and food rewards, parasitoids use those signals and resources, microbes alter nectar chemistry and odor, and hyperparasitoids add yet another trophic level.
