# Glowworm beetle (*Phengodidae*)

Glowworms are fascinating beetles that light up the night with a magical glow. They are like tiny lanterns in the dark that shine steadily instead of flashing. Scientists think the light warns predators that they taste bad.

- **Category:** [Insects](https://www.snappit.app/explore/categories/insect)
- **Rarity:** Common
- **Danger:** 1/5 · Very low
- **Habitat:** Forests and dry areas

![Glowworm](https://res.cloudinary.com/drieglelr/image/upload/v1771424469/objects/6124.jpg)

## Appearance

The glowworm larva, and the wingless adult female that looks just like it, has a long, soft, segmented body with pairs of glowing spots along its sides. Some species also have red lights on the head. Without wings it looks worm-like. The adult male is a small brown to black beetle, about 6–35 mm long, with feathery antennae.

## Taxonomy

- **Kingdom:** Animalia
- **Phylum:** Arthropoda
- **Class:** Insecta
- **Order:** Coleoptera
- **Family:** Phengodidae

## Glowworm beetle, up close

Glowworm beetles (family Phengodidae), also called railroad worms, are soft-bodied beetles found almost only in the Americas. Their larvae and wingless, larva-shaped adult females glow from pairs of lights along the body, while the small winged males have feathery antennae. Railroad worms of the genus Phrixothrix also carry a red light on the head: the only true red light known from a land animal.

Also called: Railroad worm, Glowworm beetle, Phengodid beetle.

A beetle that looks like a tiny night train: green lights down its sides and, in some species, a red lamp on its head. Spin it, tap it, then test yourself.

### Special abilities

- **Railway Lights** (11 pairs steady side lights): Railroad worms glow from a row of paired lights along the body. They shine steadily, like the windows of a night train, instead of flashing like many fireflies. [1][3][4]
  - Phrixothrix has 11 pairs of side lights and 2 head lights.
  - The side lights glow green to yellow, peaking at about 535–565 nm.
  - Females often glow nonstop while curled around their eggs. In some groups the males glow, in one scientist's words, “continuously and uncontrollably” all their adult life.
- **Red Headlamp** (628 nm reddest beetle light): Phrixothrix railroad worms carry a red light on the head. It is the only true red light known from any land animal. [1][2][3][8][9]
  - The head lights of Phrixothrix hirtus peak at about 628 nm in the live animal. Its relative P. vivianii has green side lights at 542 nm.
  - Both colours use the same fuel, luciferin. The difference is the enzyme: head and side lights use different forms of luciferase.
  - Exactly what the red light is for is still an open question.
  - Peak colour of the light: Railroad worm head light 628 nm; Orange railroad worm (Euryopa) 600 nm; Railroad worm side light 542 nm; Australian glowworm (a fly) 488 nm
- **Millipede Meal** (2 hollow, sickle-shaped jaws): Glowworm beetle larvae hunt millipedes. They stop their prey so quickly that it cannot release its bad-tasting defence chemicals, then drink a liquid meal. [5][4]
  - In one study, a Phengodes larva pierced a millipede's skin with its hollow jaws and passed in digestive juice.
  - The millipede stopped moving almost at once, so it could not release its benzoquinone defences.
  - The larva then drank the softened insides. Only the hard outer skeleton and the sealed chemical sacs were left.
- **Warning Curl** (24 lights on a Phrixothrix; still debated): When disturbed, a glowworm beetle larva or female may curl up and glow. Scientists think the light warns night-time predators that it tastes bad, but this is not fully proven. [4][1][10][11]
  - Photos in a University of Florida guide show a Phengodes curled up after being disturbed, and curled up while glowing.
  - Current evidence suggests the glow is a warning signal to nocturnal predators.
  - Another idea is that switching the lights on suddenly may startle an attacker.
  - A 99-million-year-old fossil relative had a light organ that probably served for defence too.
- **Scent Feathers** (12 segments in each male antenna): Male glowworm beetles have big, feathery antennae. They use them to track the scent of a female through the night air. [4][2]
  - The antennae have comb-like branches on 12 segments.
  - Males find females by following their pheromone, not their glow.
  - Scientists found an expanded set of odour-binding genes in the genome of Phrixothrix hirtus.
- **Larva for Life** (3 vs 12 antenna segments, female vs male): Females never grow wings. They become adults but keep the soft, segmented shape of a larva, while males turn into small winged beetles. [4][7]
  - A female keeps larva-like antennae with 3 segments, larva-like legs with a single claw, and simple eyes instead of compound eyes.
  - She can still be told from a larva: she has an opening for laying eggs near the tail.
  - Males are brown to black beetles about 6–35 mm long, with short wing covers.
  - Females are much larger than males.
- **Light Factory** (15 in 100 reactions give off red light): Inside each light, cells mix a fuel called luciferin with oxygen and energy, helped by an enzyme called luciferase. The fuel is the same for every colour; the enzyme sets the colour. [3][12][13][1][14][15][16]
  - Railroad worms use the same luciferin as fireflies and click beetles, even though beetles seem to have evolved light more than once.
  - Different forms of luciferase make the green side lights and the red head lights. The two enzymes are 71% identical.
  - The red enzyme is less efficient: about 15 in every 100 reactions make light, compared with more than 40 for green beetle enzymes.
  - Scientists use the red enzyme to make cells glow in medical research, because red light passes through blood-rich tissue better than green light.
  - Light made per 100 reactions: Red railroad worm enzyme 15 %; Green beetle enzymes >40
- **Glowing Guard** (53 eggs laid by one female): A mother glowworm beetle lays her eggs in a group on the ground and curls her body around them, often glowing as she guards them. [4]
  - One Phengodes female laid 53 eggs, in a record from 1906.
  - Western banded glowworm eggs are about 2.75 mm across; most species have smaller eggs.
  - The eggs glow too, though it can take up to a month after laying before they light up.
  - She may stay curled around them until they hatch, but nobody is sure.

### Body parts

- **Head light** (628 nm deep red light) [1][2][3]
  - Railroad worms of the genus Phrixothrix have two small lights on the head that glow red.
  - In Phrixothrix hirtus the red glow peaks at about 628 nm, the reddest light measured from any glowing beetle.
  - It is the only true red light known from a land animal.
- **Side lights** (11 pairs lights along the body) [1][3][4]
  - Phrixothrix has 11 pairs of lights along its body: one light on each side of a segment.
  - They glow green to yellow, at about 535–565 nm.
  - In the dark they look like the lit windows of a train at night, which is how railroad worms got their name.
- **Jaws** (Hollow sickle-shaped jaws) [4][5]
  - Each jaw is curved like a sickle and has a channel running inside it from base to tip.
  - The larva uses its jaws to pass digestive juice into its prey, which softens the prey's insides.
  - Then it drinks the liquid meal.
- **Eyes** [4]
  - Larvae and adult females have tiny simple eyes with a single lens, not the big compound eyes most adult insects have.
  - This is one of the clues that a female keeps a larva's body all her life.
- **Antennae** (12 segments in a male antenna) [4][2]
  - A female's antennae are short and larva-like, with just 3 segments.
  - Most males have large, feather-like antennae with 12 segments and comb-like branches.
  - Males use them to follow the scent (pheromone) a female gives off, not her light.
  - The genome of Phrixothrix hirtus has an expanded family of odour-binding genes.
- **Wings** (< ½ wing covers vs wings) [4][6]
  - Only males have wings. Their hard front wings (elytra) are less than half as long as the hind wings.
  - Males fly at night and are often caught at lights and light traps.
  - In the western banded glowworm of California, males carry genes between areas, while the wingless females stay close to home.
- **Body** (15–65 mm full-grown larva) [4][7]
  - The long, soft, segmented body looks like a larva's, even in adult females.
  - A full-grown larva is 15–65 mm long, depending on the species. Females are much larger than males.
  - An adult female can be told from a larva by a small opening for laying eggs near the tail end.
- **Legs** [4]
  - Six short, larva-like legs, each ending in a single claw, carry females and larvae through soil and leaf litter.
  - Larvae glow in wet soil, and in humid tropical forests they also climb on bark and leaves.
- **Prey** [4][5]
  - Glowworm beetle larvae are hunters that feed on millipedes.
  - Many millipedes defend themselves with bad-tasting chemicals called benzoquinones.
  - A Phengodes larva paralyses its millipede so fast that the chemicals stay locked in their glands. At the end, only the millipede's hard outer skeleton and its sealed chemical sacs are left.

### Stats

| Stat | Value | Notes |
|---|---|---|
| Species | ≈250 | 244 counted in 2023, almost all in the Americas [2][7] |
| Side lights | 11 pairs | in Phrixothrix, plus 2 red head lights [1] |
| Head light colour | 628 nm | deep red: the reddest beetle light measured [1] |
| Side light colour | 535–565 nm | green to yellow in Phrixothrix [3] |
| Larva length | 15–65 mm | full-grown larva, depending on species [4] |
| Male length | 6–35 mm | small winged beetles [4] |
| Eggs | 53 | laid by one Phengodes female (1906 record) [4] |
| Time as a pupa | 12–35 days | western banded glowworm: 12–13 days for females, 20–35 for males [4] |
| Genome size | ≈3.4 Gb | Phrixothrix hirtus: the largest known in its beetle superfamily [2] |
| Red light efficiency | 15% | of reactions give off light, vs over 40% for green beetle enzymes [14] |

### Photos

- [Lights on, lights off: the two looks of a railroad worm](https://commons.wikimedia.org/wiki/File:Railroad_worm.jpg) (photo: Aaron Pomerantz, CC BY 2.0)
- [Phrixothrix hirtus, the red-light railroad worm, in Brazil](https://commons.wikimedia.org/wiki/File:Phrixothrix_hirtus_in_the_Atlantic_forest_01.jpg) (photo: Thomas Fuhrmann, CC BY-SA 4.0)
- [A Phengodes in Missouri: a female or a larva](https://commons.wikimedia.org/wiki/File:Glowworm_Phengodes_sp_(48043672568).jpg) (photo: Andy Reago & Chrissy McClarren, CC BY 2.0)
- [Female or larva? Experts check for the tiny egg opening](https://commons.wikimedia.org/wiki/File:Glow_Worm_(Phengodes_plumosa%3F)_(10700020145).jpg) (photo: Benjamin Smith, CC BY 2.0)
- [Western banded glowworm (Zarhipis integripennis)](https://commons.wikimedia.org/wiki/File:Glowworm_(4213020277).jpg) (photo: nancybeetoo, CC BY 2.0)
- [A winged male: note the feathery antennae](https://commons.wikimedia.org/wiki/File:Glowworm_beetle%2C_male_(Phengodidae%2C_Phengodes_sp.)_(27583893315).jpg) (photo: Insects Unlocked, CC0)
- [The European glow-worm is a firefly, not a railroad worm](https://commons.wikimedia.org/wiki/File:Lampyris_Noctiluca_Female_Firefly_1.jpg) (photo: Tero Keski-Valkama, CC0)
- [European glow-worm in the UK](https://commons.wikimedia.org/wiki/File:Glow_worm%2C_Lampyris_noctiluca_(18979089824).jpg) (photo: AJC1, CC BY-SA 2.0)

### Questions

- **What is the difference between a glowworm and a firefly?** Glowworm is a name, not one animal. Glowworm beetles of the Americas (Phengodidae) are their own beetle family. The European glow-worm is actually a firefly whose females have no wings. The New Zealand glowworm is a fly larva. [4][18][21]
- **Why is it called a railroad worm?** Its rows of glowing spots along the body look like the lit windows of a train at night. [4]
- **Why do glowworm beetles glow?** Scientists think the glow warns night-time predators that they taste bad. Males find females by scent, not light, so the glow is probably not a love signal. [4]
- **What do glowworm beetles eat?** The larvae and larva-shaped females hunt millipedes, paralysing them quickly with digestive juice from their hollow jaws. Adult males are short-lived and probably do not feed. [4][5][7]
- **Where do glowworm beetles live?** Almost all live in the Americas, from southern Canada to Chile, in places from dry parts of California to tropical forests. A small group lives in Turkey and the Middle East. [7][20][4][6]
- **Do male glowworm beetles glow?** Usually not, but males in the group that includes Phrixothrix glow all their adult life, and Stenophrixothrix males give off yellow light. [4][20]
- **Are glowworm beetles dangerous?** There is no sign that they are a danger to people: their jaws are made for millipedes. Still, don't pick them up. When handled, a railroad worm larva may release a reddish liquid that may taste bad or irritate. Watch without touching, and wash your hands if you do touch one. [5][10]
- **How can I see glowworm beetles in the wild?** Look on warm, damp nights on soil and leaf litter. Use a dim red light, which disturbed glow-worm mating less than white or blue light in experiments. Watch without touching and leave them where they are. [4][31]

### Glowworm beetle myths and facts

The word glowworm causes a lot of mix-ups. Test what you know.

- "Glowworms are a kind of worm." **Myth!** They are insects. A glowworm beetle is the larva, or the larva-shaped adult female, of a beetle in the family Phengodidae. [4]
- "Every animal called a glowworm is the same kind of creature." **Myth!** The name covers at least three unrelated groups: glowworm beetles of the Americas (Phengodidae), the European glow-worm, which is a firefly (Lampyris noctiluca), and the New Zealand glowworm, which is the larva of a fungus gnat, a kind of fly (Arachnocampa luminosa). [4][18][21][22]
- "Railroad worms flash on and off like fireflies." **Myth!** They glow steadily. Females often glow nonstop while curled around their eggs, and males of some groups glow all their adult life. [4]
- "The railroad worm's red head light is the only red light made by a land animal." **Fact!** Phrixothrix hirtus makes the only true red bioluminescence known on land, peaking at about 622–628 nm. [2][1][23]
- "Male glowworm beetles find females by following their glow." **Myth!** Males follow the female's scent (pheromone) with their feathery antennae. Her light does not seem to be the cue. [4]
- "Glowworm beetle larvae eat snails." **Myth!** As far as scientists know, they hunt millipedes. Snail-eating is what European glow-worm larvae do. [4][5][19]
- "Male glowworm beetles never glow." **Myth!** Many don't, but males in the group that includes Phrixothrix glow throughout their adult life, and Stenophrixothrix males give off yellow light. [4][20]
- "A female railroad worm is just a baby that never grew up." **Myth!** She is a full adult that mates and lays eggs. She simply keeps a larva's body shape and never grows wings. [4]

### Glowworm beetle records

Small beetles, big superlatives. Each one is backed by a study.

- Only red light on land: Phrixothrix hirtus, 622–628 nm (The only land animal known to make true red bioluminescence.) [2][1]
- Widest range of light colours: Railroad worms (Phengodidae), Green to red (Their enzymes make the widest range of colours of any beetle group, from about 542 nm green to 628 nm red.) [8][24][1]
- Biggest genome in its superfamily: Phrixothrix hirtus, ≈3.4 Gb (The largest genome described among the click beetles, fireflies and their relatives (Elateroidea).) [2]
- Oldest glowing relative: Cretophengodes azari, ≈99 million years (A male beetle in amber from Myanmar, with a light organ on its abdomen, linking glowworm beetles to harder-bodied relatives.) [11]
- First orange railroad-worm enzyme: Euryopa clarindae, 600 nm (In 2024 scientists described the first orange-glowing railroad worm luciferase, from males of a rare species of the Brazilian Cerrado.) [8]

### The railroad worm's red light

Why scientists study one small Brazilian beetle's head lamp.

- **628 nm** reddest beetle light. Measured from the head lights of Phrixothrix hirtus. The side lights of a related species glow green at 542 nm. [1]
- **71%** same enzyme recipe. The red and green luciferases share 71% of their building blocks. Small changes shift the colour. [1]
- **15 in 100** reactions make red light. The red enzyme is dimmer than green ones, which manage more than 40 in 100. [14]
- **9.8×** brighter in the lab. By changing a few building blocks, scientists made red enzymes up to 9.8 times brighter in cell extracts. [23]
- **Red** passes through tissue. Blood and skin absorb red light less than green, so researchers use red-glowing enzymes to follow infections and disease inside living animals. [15]

Railroad worm red light comes from the same luciferin fuel as a firefly's yellow-green; only the enzyme differs.

### Life of a glowworm beetle

From a glowing egg to a winged male or a larva-shaped mother. Timings come from the few species that have been studied.

- **Egg**: Laid in a group. A mother lays her eggs together on the ground, 53 in one record, and curls around them. [4]
- **Up to 1 month**: Eggs light up. The eggs glow, but it can take up to a month after laying before they become luminous. [4]
- **Larva**: Millipede hunter. The larva hunts millipedes in soil and leaf litter and grows to 15–65 mm. [4][5]
- **Pupa**: The big change. In the western banded glowworm, a female spends 12–13 days as a pupa and a male 20–35 days. [4]
- **Adult female**: Larva shape for life. She stays wingless and larva-like, glows, and gives off a scent that draws in males. [4]
- **Adult male**: Short night flights. The winged male follows her scent through the dark. Males are short-lived and probably do not feed. [4][7]
- **Mother**: Glowing guard. After mating she curls around her new eggs, often glowing continuously, perhaps until they hatch. [4]

### Railroad worm vs European glow-worm vs New Zealand glowworm

Three animals, one confusing name. Only the first is a glowworm beetle.

| | Railroad worm | European glow-worm | New Zealand glowworm |
|---|---|---|---|
| What it is [4][18][21][22] | A beetle (family Phengodidae) | A firefly beetle (family Lampyridae) | A fly: the larva of a fungus gnat (Keroplatidae) |
| Who glows [4][20][17][22] | Larvae, wingless females, and the males of some groups | Above all the wingless adult female | The larva |
| Light colour [3][1][18][25][9] | Green-yellow sides (535–565 nm), red head (600–628 nm) in Phrixothrix | Green, a little bluer than an American firefly's | Blue-green (about 488 nm in an Australian relative) |
| Why it glows [4][17][22] | Thought to warn predators it tastes bad | To attract flying males | To lure flying insects to its sticky threads |
| Larva's food [4][5][19][26][22] | Millipedes | Snails | Small flying insects caught on sticky silk lines |
| Where [7][20][17][25] | The Americas, from southern Canada to Chile (a few in Turkey and the Middle East) | Europe | New Zealand |
| Light chemistry [3][18][25] | Firefly-type luciferin | Firefly-type luciferin | A completely different luciferin |

Glowworm beetles and European glow-worms are both beetles, yet genome studies suggest beetles evolved light more than once.

### Are glowworm beetles endangered?

Nobody knows yet. Glowworm beetles are rarely seen, many species have not even been named, and none has been assessed for the IUCN Red List.

- **IUCN Red List:** Not Evaluated (NE) (Trend unknown). No glowworm beetle species has an IUCN assessment, so how they are doing is unknown. [27][4]
- Not on the IUCN Red List (checked October 2026)
- **Threat: Forest loss** (>80%): Many Brazilian railroad worms live in the Atlantic Forest and Cerrado. More than 80% of the Atlantic Forest's remaining patches are smaller than 50 ha. [20][28]
- **Threat: Light pollution** (15 nights): Artificial light at night harms many insects. In the European glow-worm, females near lights glowed for up to 15 nights without finding a mate. [29][30]
- **Threat: Too little known** (≈100): Around 100 species may be waiting in museum collections to be named. It is hard to protect animals nobody has described. [4]
- **Helping: Darker nights**: Switching off or dimming outdoor lights helps night insects. In glow-worm experiments, red and yellow lamps disturbed mating less than white or blue ones. [29][31]
- **Helping: Naming and studying**: Scientists are still describing species and using DNA to match larvae with their adults, which had been done for only one Brazilian species before 2025. [20]
- **Helping: Look, don't take**: Females cannot fly and move only short distances, so local groups depend on the females staying where they are. [6]
- **European glow-worm (Lampyris noctiluca)** (NT): Listed as Near Threatened. Artificial light makes it harder for females to attract mates. [27][17][30]
- **North American fireflies** (MIXED): Of 132 species assessed, at least 18 (14%) are threatened, mainly by habitat loss, light pollution and climate change. [32]

### Glowworm beetle light signals

- Steady glow: Normal for a railroad worm: the lights shine for long periods instead of flashing in a code. [4]
- Curled up and glowing: A reaction to being disturbed. The glow is thought to warn predators that it tastes bad. [4]
- Lights switched on suddenly: May startle a predator. This idea has not been well tested. [10]
- Curled around eggs: A mother guarding her eggs, often glowing continuously. [4]
- Male flying to a lamp: Males are active at night and are often drawn to lights and light traps. [4][20]

### Forms

- **Female (railroad worm)**: Larva-shaped for life: a long, soft, segmented body with green-yellow lights along the sides and, in Phrixothrix, red lights on the head. (Wingless adult · glows · lays eggs) [4][1]
- **Winged male**: A small brown-to-black beetle, about 6–35 mm long, with short wing covers and big feathery antennae. (Flies at night · follows scent · short-lived) [4][7]
- **Larva**: Almost identical to the female, but with no egg opening. It grows to 15–65 mm before turning into a pupa. (Hunts millipedes · glows) [4][5]
- **European glow-worm**: A different beetle: the wingless female of a firefly, Lampyris noctiluca. She glows steadily at night to attract flying males. (Firefly family (Lampyridae) · larvae eat snails) [17][18][19]

### Glowworm beetle quiz

1. What kind of animal is a glowworm beetle? **A beetle.** Despite the name, it is a beetle in the family Phengodidae. [4]
2. Why are they called railroad worms? **Their lights look like lit train windows.** The rows of lights along the body look like the windows of a train at night. [4]
3. What colour is the head light of a Phrixothrix railroad worm? **Red.** It glows red, peaking at about 628 nm. [1]
4. How many pairs of side lights does Phrixothrix have? **11.** Phrixothrix has 11 pairs of side lights and 2 head lights. [1]
5. What do glowworm beetle larvae mainly eat? **Millipedes.** They hunt millipedes. Snails are the food of European glow-worm larvae. [4][5]
6. How do males find females? **By following her scent.** Males follow the female's pheromone with their feathery antennae. [4]
7. Which form of the glowworm beetle has wings? **The male.** Only males have wings. Females keep a larva's shape all their lives. [4]
8. How does a larva stop a millipede releasing its defence chemicals? **It paralyses it fast with digestive juice from its hollow jaws.** The millipede stops moving almost at once, so its chemicals stay locked in their glands. [5]
9. What is the New Zealand glowworm? **The larva of a fungus gnat, a kind of fly.** It is a fly larva that lures insects to sticky threads. Same name, very different animal. [21][22]
10. How does a railroad worm's light usually behave? **It glows steadily.** Railroad worms glow steadily instead of flashing. [4]
11. What does a mother glowworm beetle do after laying her eggs? **Curls her body around them.** She curls around her eggs, often glowing, perhaps until they hatch. [4]
12. Why do medical researchers like the railroad worm's red enzyme? **Red light passes through blood-rich tissue better.** Blood and skin absorb red light less, so red glows can be seen from deeper inside the body. [15]

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15. [Viviani VR, Bevilaqua VR, de Souza DR, Pelentir GF, Kakiuchi M, Hirano T (2020). A very bright far-red bioluminescence emitting combination based on engineered railroad worm luciferase and 6'-amino-analogs for bioimaging purposes. International Journal of Molecular Sciences 22:303.](https://doi.org/10.3390/ijms22010303)
16. [Viviani VR (2002). The origin, diversity, and structure function relationships of insect luciferases. Cellular and Molecular Life Sciences 59:1833–1850.](https://doi.org/10.1007/PL00012509)
17. [Elgert C, Hopkins J, Kaitala A, Candolin U (2020). Reproduction under light pollution: maladaptive response to spatial variation in artificial light in a glow-worm. Proceedings of the Royal Society B 287:20200806.](https://doi.org/10.1098/rspb.2020.0806)
18. [Sala-Newby GB, Thomson CM, Campbell AK (1996). Sequence and biochemical similarities between the luciferases of the glow-worm Lampyris noctiluca and the firefly Photinus pyralis. Biochemical Journal 313:761–767.](https://doi.org/10.1042/bj3130761)
19. [Krämer J, Hölker P, Predel R (2024). How to overcome a snail? Identification of putative neurotoxins of snail-feeding firefly larvae (Coleoptera: Lampyridae, Lampyris noctiluca). Toxins 16:272.](https://doi.org/10.3390/toxins16060272)
20. [Roza AS, Souza DR, Pelentir GF, Barbosa FF, Mermudes JRM, Viviani VR (2025). Bioluminescence, morphology, biological aspects and molecular association of larvae and adults of Stenophrixothrix (Coleoptera: Phengodidae). Zootaxa 5689(3).](https://doi.org/10.11646/zootaxa.5689.3.4)
21. [von Byern J, Chandler P, Merritt D, et al. (2019). Biomechanical properties of fishing lines of the glowworm Arachnocampa luminosa (Diptera; Keroplatidae). Scientific Reports 9:3082.](https://doi.org/10.1038/s41598-019-39098-1)
22. [Merritt DJ, Patterson R (2018). Environmental influences on the bioluminescence display of the glow-worm, Arachnocampa flava. Austral Entomology 57:107–117.](https://doi.org/10.1111/aen.12274)
23. [Li X, Nakajima Y, Niwa K, Viviani VR, Ohmiya Y (2010). Enhanced red-emitting railroad worm luciferase for bioassays and bioimaging. Protein Science 19:26–33.](https://doi.org/10.1002/pro.279)
24. [Arnoldi FG, da Silva Neto AJ, Viviani VR (2010). Molecular insights on the evolution of the lateral and head lantern luciferases and bioluminescence colors in Mastinocerini railroad-worms (Coleoptera: Phengodidae). Photochemical & Photobiological Sciences 9:87–92.](https://doi.org/10.1039/b9pp00078j)
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## Measurements & details

- **Size:** 6-65 mm
- **Lifespan:** 200-700 days
- **Leg Count:** 6

## Diet & Feeding

Glowworm larvae are tiny hunters. As far as scientists know, they hunt millipedes.

- **Age differences:** Adult males generally do not eat, while larvae are active predators.
- **Primary Foods:** Millipedes

## Ecological connections

- **Hunts:** American Millipede (*Narceus americanus*) — Glowworm larvae prey on these millipedes on the forest floor.
- **Eaten by:** Masked Shrew (*Sorex cinereus*) — Shrews might eat glowworm larvae that live in leaf litter, but this has not been confirmed.
- **Eaten by:** [American Robin](https://www.snappit.app/explore/american-robin) (*Turdus migratorius*) — Ground-feeding birds like robins might eat glowworm larvae, but this has not been confirmed.

## Traits

- [Wildlife](https://www.snappit.app/explore/traits/wildlife): Wildlife encompasses all undomesticated animal and plant life existing in their natural habitats.
- [Forest](https://www.snappit.app/explore/traits/forest): Forest habitats are terrestrial environments dominated by dense tree cover, supporting a high diversity of plant and animal life.
- [Glowing](https://www.snappit.app/explore/traits/glowing): Pertaining to organisms that emit light through bioluminescence or fluorescence.
- [Nocturnal](https://www.snappit.app/explore/traits/nocturnal): Nocturnal animals are primarily active during the nighttime hours, typically resting or sleeping during the day.

## Collections

- [Insects](https://www.snappit.app/explore/collections/insects)

## Safety

**Danger:** 1/5 · Very low

Avoid touching or disturbing glowworms in their natural habitat to ensure they can continue their important role in the ecosystem.

## Frequently Asked Questions

### How to identify Glowworm beetle?

Look for hard wing covers meeting in a line down the back, then compare the antennae, body shape, legs and markings. Metallic colors shift a lot with lighting. Beetle Identifier: upload a photo and compare the visible details.

### How big is Glowworm beetle?

6-65 mm

### How long does Glowworm beetle live?

200-700 days

### What does Glowworm beetle eat?

Glowworm larvae are tiny hunters. As far as scientists know, they hunt millipedes.

### Where is Glowworm beetle usually found?

Forests and dry areas

### How many legs does Glowworm beetle have?

6

## More Insects

- [Common Eastern Bumble Bee](https://www.snappit.app/explore/common-eastern-bumble-bee) (*Bombus impatiens*)
- [Spotted Lanternfly](https://www.snappit.app/explore/spotted-lanternfly) (*Lycorma delicatula*)
- [Brown-belted Bumble Bee](https://www.snappit.app/explore/brown-belted-bumble-bee) (*Bombus griseocollis*)
- [Eastern Carpenter Bee](https://www.snappit.app/explore/eastern-carpenter-bee) (*Xylocopa virginica*)

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Source: [Glowworm beetle: Facts & Places to See — Snappit](https://www.snappit.app/explore/glowworm)