# Bronze Beetle (*Chrysolina bankii*)

The Bronze Beetle is a shiny little leaf beetle that loves to munch on plants. Its metallic bronze color makes it easy to spot in sunny, open places.

- **Category:** [Insects](https://www.snappit.app/explore/categories/insect)
- **Rarity:** Common
- **Danger:** 1/5 · Very low
- **Snaps:** 1
- **Habitat:** Sunny, open places with plantains and mints, often near the coast

![Bronze Beetle](https://commons.wikimedia.org/w/index.php?title=Special:Redirect/file/Chrysomelidae._Escaravello_en_Bastavales%252C_Brion._Marzo.jpg&width=800)

Photo: http://gl.wikipedia.org/w/index.php?title=Usuario:Xan_de_ningures, CC BY-SA 3.0 · [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Chrysomelidae._Escaravello_en_Bastavales%252C_Brion._Marzo.jpg)

## Appearance

The Bronze Beetle has a distinctive oval, dome-shaped body with a highly reflective, metallic sheen that often appears bronze, copper, or greenish. Its iridescent shell can shimmer with different colors depending on the light, making it stand out from duller leaf beetles.

## Taxonomy

- **Kingdom:** Animalia
- **Phylum:** Arthropoda
- **Class:** Insecta
- **Order:** Coleoptera
- **Family:** Chrysomelidae
- **Genus:** Chrysolina

## Bronze beetle, up close

The bronze beetle (Chrysolina bankii) is a metallic bronze leaf beetle, 8–10.7 mm long, with orange-brown to dark brown legs. It is native to western Europe, from southern England to Italy and Iberia, and to north-west Africa, the Canary Islands and Madeira, and it has been introduced to California. For its genus it eats an unusually wide range of plants, from ribwort plantain and mints to thistles and rosemary.

Also called: Chrysolina banksi, Chrysolina banksii.

A metallic leaf beetle with one of the widest menus in its genus. Spin it, tap it, then test yourself.

### Special abilities

- **Bronze Shine** (3 ways beetles make metallic colour): Its shell gleams bronze, copper or greenish depending on the light. In beetles, shine like this is made by structure, not paint. [3]
  - Scientists group beetle shine into three kinds: stacked thin layers (multilayer reflectors), crystal-like 3D patterns and fine ridges called diffraction gratings.
  - Beetles are sometimes called “living jewels” because of these effects.
  - No one has yet measured the bronze beetle’s shell, so which kind it uses is not known.
- **Wide Menu** (5 plant families eaten): Most Chrysolina beetles stick to one plant family. The bronze beetle eats from five. [6][2]
  - It eats plants from nine genera of the mint family, plus plantains and some daisy-family, buttercup-family and dock-family plants.
  - In Britain it is found especially on ribwort plantain and on mints and their relatives.
  - Rosemary and Dittrichia viscosa were added to the list in 2020, and both were confirmed in the lab.
  - Plant families eaten: Bronze beetle 5; Most Chrysolina species 1 (less often 2)
- **Chemical Shield** (Self-made defence chemicals (genus); still debated): Chrysolina leaf beetles give off defensive fluids. Whether the bronze beetle does the same has not been tested. [4][11][12]
  - Defensive fluids of Chrysolina beetles contain cardenolides (cardiac glycosides), chemicals that affect the heart.
  - A 1977 study found that the beetles make these chemicals themselves instead of collecting them from their food plants.
  - Other leaf beetles in the same subfamily borrow defence chemicals from their host plants instead.
  - In some of those relatives, the larvae push out little glands on their backs and release defensive fluid when disturbed.
- **Grip Pads** (45× body weight held (rosemary beetle)): Hairy pads on its feet let it climb leaves and hang on underneath. [7][8]
  - Chrysolina beetles have hairy adhesive pads on their feet. On waxy leaves, wax sticks to the hairs and grip drops sharply.
  - In the rosemary beetle, males have special disc-tipped hairs. Clinging to a female’s back, they held about 45 times their own body weight, females about 30 times.
  - No one has measured the bronze beetle’s grip yet.
- **Drop and Freeze** (Freeze a defence many insects use; still debated): When touched, many beetles drop from their plant and lie still. It is often said that the bronze beetle does this too, but it has not been studied. [13]
  - Playing dead (thanatosis) usually happens after a predator has already touched its prey.
  - Scientists think it can stop a predator from attacking further.
  - We found no study of this behaviour in the bronze beetle.
- **Winter Grub** (Larva usual winter stage in Britain): In Britain it usually gets through the winter as a larva. In warmer places adults keep going too. [2][14]
  - Records peak twice a year: in April and May, and again from September to November.
  - Few are recorded in July and August. Why has not been studied for this species.
  - In Britain, September and October have the most records of all.
  - Records in four months: May (peak) 2,937; October 2,581; January 303; August 285
- **Hidden Wings** (Unknown flight ability; still debated): Under the wing cases sit folded flight wings. Whether the bronze beetle uses them is not known. [1][5][15]
  - Most beetles have hard front wings (elytra) with the hind wings folded beneath.
  - California’s plant-health officials say it “presumably can fly”, but we found no record of it flying.
  - Losing flight has happened again and again in insects. Some Chrysolina species cannot fly, and experts disagree about whether the rosemary beetle can.

### Body parts

- **Wing cases** (Bronze metallic wing cases) [1][2][3]
  - The wing cases (elytra) are the beetle’s hardened front wings. The thin flight wings fold away underneath them.
  - They are metallic bronze, dotted with small pits scattered at random.
  - In shiny beetles, metallic colour is made by tiny structures in the shell that reflect light, not by metal-coloured pigment.
- **Thorax shield** [2][4]
  - The shield behind the head (the pronotum) is the same metallic bronze as the wing cases.
  - Chrysolina leaf beetles give off defensive fluids containing chemicals called cardenolides, which they make themselves rather than taking from their food plants.
  - These chemicals have not been tested in the bronze beetle itself.
- **Flight wings** (Unknown can it fly?) [1][5]
  - Most beetles fold their hind wings away under the wing cases.
  - Whether the bronze beetle flies is not well recorded. California’s plant-health officials say it “presumably can fly”.
  - Some relatives, such as Chrysolina sulcicollis and Chrysolina virgata, cannot fly at all.
- **Head and jaws** (5 plant families eaten) [6][2]
  - Adults and larvae both chew leaves.
  - Its food plants come from five families: the mint family (nine genera), plantains, the daisy family, the buttercup family and the dock family.
  - In Britain it is found especially on ribwort plantain and mint-family plants, including mints.
- **Legs and feet** (Orange-brown leg colour) [2][7][8]
  - Its legs are orange-brown to dark brown.
  - Chrysolina feet have pads of tiny hairs that cling to leaves. Waxy leaf surfaces make them slip.
  - In the rosemary beetle, a close relative, a male clinging to a female’s back holds on with about 45 times his own body weight.
- **Gut** [6][9]
  - Its gut copes with leaves from very different plants, from mints to thistles.
  - In a relative, the mint beetle Chrysolina herbacea, gut bacteria help the beetle deal with the strong-smelling chemicals of watermint.
  - No one has studied the bronze beetle’s gut bacteria yet.
- **Bitten leaf** (2 new food plants found in 2020) [6][5]
  - In 2020 a leaf-beetle expert reported two new food plants on Mallorca: rosemary, and the sticky yellow-flowered shrub Dittrichia viscosa.
  - Earlier records include milk thistle, cardoon, artichoke and a wild sage, Salvia verbenaca.
  - Rosemary is a common garden plant in California, one reason officials there think the beetle could spread widely.
- **Soil** (Larva usual winter stage in Britain) [2][10]
  - In Britain the bronze beetle usually spends the winter as a larva. In warmer places, adults are found in winter too.
  - In many leaf beetles, such as the Colorado potato beetle, the fully grown larva burrows into the soil to become a pupa.
  - Where and how the bronze beetle pupates has not been described in detail.

### Stats

| Stat | Value | Notes |
|---|---|---|
| Length | 8–10.7 mm | adult beetle; Up to about 1½ times as long as a rosemary beetle [2][16] |
| Plant families eaten | 5 | mint, plantain, daisy, buttercup and dock families; Most Chrysolina species eat from just 1 [6] |
| Mint-family genera eaten | 9 | genera of the Lamiaceae [6] |
| Species in its genus | 400+ | Chrysolina, split into 65 subgenera [17][18] |
| Leaf beetle species | 36,000+ | family Chrysomelidae, worldwide [19] |
| GBIF records | 14,927 | from 17 countries, checked October 2026 [14] |
| Busiest month | May | 2,937 GBIF records; October is next with 2,581 [14] |
| California counties | 5 | where it was established by 2022 [5] |
| Earliest US record | 2008 | research-grade iNaturalist photo, UC Berkeley campus [20] |
| Year named | 1775 | described by Johan Christian Fabricius [14] |

### Photos

- [Céret, in the French Pyrenees, May 2019](https://commons.wikimedia.org/wiki/File:20190522_C%C3%A9ret_-_Chrysolina_bankii_2.jpg) (photo: Fabricio Cardenas, CC BY-SA 4.0)
- [Feeding on a plantain leaf, Alicante, Spain](https://commons.wikimedia.org/wiki/File:Leaf_Beetle_eating_Common_Plantain_-_Flickr_-_treegrow.jpg) (photo: Katja Schulz, CC BY 2.0)
- [Els Poblets, Alicante, Spain](https://commons.wikimedia.org/wiki/File:Another_Chrysolina_bankii_-_Flickr_-_treegrow.jpg) (photo: Katja Schulz, CC BY 2.0)
- [Out and about in February](https://commons.wikimedia.org/wiki/File:Chrysolina_bankii_16-02-10_01_(24875772202).jpg) (photo: liesvanrompaey, CC BY 2.0)
- [In Spanish it is called crisomélido de Bank](https://commons.wikimedia.org/wiki/File:Chrysolina_bankii_-_Crisom%C3%A9lido_de_Bank_(6702025173).jpg) (photo: jacilluch, CC BY-SA 2.0)
- [Jimena, Andalucía, Spain](https://commons.wikimedia.org/wiki/File:Chrysolina_banksi_._Chrysomelidae_-_Flickr_-_gailhampshire.jpg) (photo: gailhampshire, CC BY 2.0)
- [Its relative the rosemary beetle](https://commons.wikimedia.org/wiki/File:Chrysolina_americana_003.jpg) (photo: Iurie Nistor, CC BY-SA 4.0)
- [Rosemary beetle, Aragon, Spain](https://commons.wikimedia.org/wiki/File:Chrysolina_americana_-_Flickr_-_S._Rae.jpg) (photo: S. Rae, CC BY 2.0)

### Questions

- **What do bronze beetles eat?** Leaves. Adults and larvae eat plants from five families, including ribwort plantain, mints and other mint-family plants, rosemary, and thistles such as milk thistle and artichoke. That is an unusually wide menu for a Chrysolina beetle. [2][6]
- **Is the bronze beetle a garden pest?** It is not known to be one. California, where it was introduced, lowered its pest rating to C in 2022 because it does not appear to be a significant pest. [5]
- **Can bronze beetles fly?** Nobody seems to know for sure. It has folded hind wings under its wing cases, and California officials say it “presumably can fly”, but some of its Chrysolina relatives cannot fly at all. [5][1]
- **Where do bronze beetles live?** In western Europe from southern England to France, Italy and Iberia, in north-west Africa from Morocco to Tunisia, and on the Canary Islands and Madeira. It has also been introduced to California. In Britain it is mostly found near the coast in the south-west. [6][5][2]
- **When is the best time to see a bronze beetle?** Spring and autumn. Records peak in April and May and again from September to November, with few in July and August. Look on plantains and mint-family plants in sunny, open places. [14][2]
- **Why is the bronze beetle so shiny?** Metallic beetle colours come from tiny structures in the shell that reflect light, which is why the colour shifts from bronze to copper or green as you move. Which structure the bronze beetle uses has not been measured. [3]
- **What is the difference between a bronze beetle and a rosemary beetle?** Both are Chrysolina leaf beetles. The bronze beetle is larger (8–10.7 mm) and plain metallic bronze. The rosemary beetle is 6–7 mm with purple and green stripes and feeds on rosemary, lavender, sage and thyme. [2][16]
- **Is it safe to touch a bronze beetle?** We found no reports of bronze beetles harming people. Still, it is best to watch it on its plant rather than pick it up: small beetles are easily hurt, and Chrysolina beetles can give off defensive fluids. If you do touch one, wash your hands. [4]

### Bronze beetle myths and facts

Some popular bronze beetle claims hold up. Others don’t, or have never been tested.

- "Bronze beetles only eat mint." **Myth!** Mints are on the menu, but so are ribwort plantain, milk thistle, artichoke, rosemary and plants in the buttercup and dock families. That is five plant families, one of the widest menus in its genus. [2][6]
- "A beetle’s metallic shine comes from metal-coloured pigment." **Myth!** Metallic beetle colours are made by tiny structures in the shell that reflect light: stacked thin layers, crystal-like patterns or fine ridges. That is why the colour shifts as you move. [3]
- "Bronze beetles are dangerous garden pests." **Myth!** California checked after the beetle settled there. Officials found it is not known to be a pest and lowered its pest rating to C in 2022. [5]
- "When disturbed, a bronze beetle drops and plays dead." **Not proven!** Many insects drop and freeze when touched, and it is often said that this beetle does too. But we found no study of the behaviour in the bronze beetle. [13]
- "Every beetle with wings can fly." **Myth!** Flight has been lost again and again in insects. Some Chrysolina beetles cannot fly at all. For the bronze beetle, officials only say it “presumably can fly”. [1][5]
- "Leaf beetles have been used to fight weeds." **Fact!** Its relative Chrysolina quadrigemina was released to control St John’s wort and succeeded in California, and Chrysolina hyperici helped in New Zealand. But C. quadrigemina also damages some native St John’s worts. [21][22][23]
- "The rosemary beetle, Chrysolina americana, comes from America." **Myth!** Despite its name, the rosemary beetle is native to Mediterranean countries in southern Europe and North Africa. It has spread across Britain since the mid-1990s. [15][19][16]
- "The bronze beetle is an endangered species." **Myth!** It has never been assessed for the IUCN Red List, and a leaf-beetle expert calls it a very common species. [14][24][6]

### Bronze beetle records

Record-breakers from the bronze beetle and its leaf beetle family.

- One of the widest menus in its genus: Bronze beetle, 5 plant families (most Chrysolina species stick to one family, less often two) [6]
- A giant family: Leaf beetles (Chrysomelidae), 36,000+ species (plant-eating beetles found worldwide) [19]
- A big genus: Chrysolina, 400+ species (sorted into 65 subgenera) [17][18]
- Weed-busting relative: Chrysolina quadrigemina, St John’s wort (successfully controlled this invasive weed in California) [21]
- Super grip: Rosemary beetle (male), ≈45× body weight (grip on a female’s wing cases, measured in a lab) [8]
- Most records: Spain, 4,189 records (of 14,927 on GBIF; France is next with 3,525) [14]

### A bronze beetle’s life

From egg to shiny adult. Some stages are still poorly known for this species.

- **Egg**: A little-known start. Little has been published about this species’ eggs. Related leaf beetles, such as the Colorado potato beetle, lay small clusters of yellow-orange eggs under leaves. [10]
- **Larva**: A leaf-chewing grub. Larvae chew leaves like the adults. On Mallorca, a few were found feeding on the sticky shrub Dittrichia viscosa, and they ate it in the lab too. [6]
- **Winter**: Winter as a grub. In Britain it usually spends the winter as a larva. In warmer places, adults are found in winter too. [2]
- **Pupa**: A change underground?. In many leaf beetles the fully grown larva burrows into the soil to become a pupa. This has not been described in detail for the bronze beetle. [10]
- **Spring**: Spring peak. Records climb in April and peak in May, with 2,937 GBIF records in that month. [14]
- **Summer**: A quiet summer. Few are recorded in July and August. Why has not been studied for this species. [14]
- **Autumn**: Second peak. Records rise again from September to November. In Britain, September and October are the busiest months. [14]
- **Adult**: Finding a mate. Adults, sometimes in mating pairs, have been found on rosemary bushes. [6]

### Bronze beetle vs Colorado potato beetle vs rosemary beetle

Three leaf beetles, three very different reputations.

| | Bronze beetle | Colorado potato beetle | Rosemary beetle |
|---|---|---|---|
| Scientific name [14][10][16] | Chrysolina bankii | Leptinotarsa decemlineata | Chrysolina americana |
| Length [2][10][16] | 8–10.7 mm | about 10 mm (3/8 inch) | 6–7 mm |
| Colours [2][10][16] | Metallic bronze, orange-brown legs | Yellowish-white wing cases with 10 black stripes | Metallic purple and green stripes |
| Main food [2][6][10][16] | Plantains, mints and other mint-family plants, some thistles | Potato, eggplant, tomatillo | Rosemary, lavender, sage, thyme |
| Pest? [5][10][25][16] | Not known to be a pest | Major potato pest that quickly evolves resistance to insecticides | Garden pest of herbs |
| Winter [2][10][16] | Usually as a larva (Britain) | Adults 13–25 cm underground | Adults present all year |

The bronze beetle and the rosemary beetle are in the same genus, Chrysolina.

### Is the bronze beetle endangered?

No. It has never been assessed by the IUCN, but it is described as very common.

- **IUCN Red List:** Not Evaluated (NE) (Trend unknown). A leaf-beetle expert calls it very common. In Britain it is widespread in the south-west, usually near the coast, and can be locally common. [14][24][6][2]
- Not evaluated by the IUCN Red List (checked October 2026).
- **Threat: Threats not studied**: We found no study of threats to the bronze beetle. Nobody has measured whether its numbers are rising or falling. [14]
- **Threat: Moved by people**: Beetles can travel with plants. California has intercepted it on plant material from Texas and in parcels from Oregon. Officials say it might have effects on native plants that nobody has spotted yet. [5]
- **Helping: Recording it** (15,429): Photos on iNaturalist and records sent to UK Beetle Recording show where it lives and when it is active. [20][2]
- **Helping: Watching the newcomers**: California’s plant-health officials track where it turns up. In 2022 it was known from five counties. [5]

### Family

- **Adult bronze beetle**: Oval and domed, 8–10.7 mm long, metallic bronze all over with orange-brown to dark brown legs. (Usually near the coast in Britain; very common in south-west Europe) [2][6]
- **Rosemary beetle (Chrysolina americana)**: Smaller, 6–7 mm, with metallic purple and green stripes on its wing cases and thorax. (A garden pest of rosemary, lavender, sage and thyme) [16]
- **Larva**: A soft, leaf-chewing grub. We found no detailed published description of its colours, so the model shows a generic leaf-beetle larva. (In Britain, usually the stage that gets through winter) [2][6]
- **Eggs**: Little has been published about this species’ eggs. Related leaf beetles, such as the Colorado potato beetle, lay small clusters of yellow-orange eggs under leaves. (Shown for comparison with a relative) [10]

### Bronze beetle quiz

1. How long is an adult bronze beetle? **8–10.7 mm.** Adults are 8–10.7 mm long. [2]
2. How many plant families does the bronze beetle eat from? **5.** Five: the mint, plantain, daisy, buttercup and dock families. [6]
3. Which plant is a favourite of bronze beetles in Britain? **Ribwort plantain.** In Britain it is found especially on ribwort plantain and mint-family plants. [2]
4. How does the bronze beetle usually spend the winter in Britain? **As a larva.** Usually as a larva. In warmer places adults are found in winter too. [2]
5. What is the bronze beetle’s IUCN Red List status? **Not evaluated.** It has never been assessed by the IUCN. [14][24]
6. Where in the USA has the bronze beetle settled? **California.** By 2022 it was established in five California counties. [5]
7. Which relative was used to control the weed St John’s wort in California? **Chrysolina quadrigemina.** Chrysolina quadrigemina successfully controlled St John’s wort in California. [21]
8. What colour are the rosemary beetle’s stripes? **Purple and green.** Rosemary beetles have metallic purple and green stripes. [16]
9. About how many species of leaf beetle are there? **More than 36,000.** There are more than 36,000 leaf beetle species worldwide. [19]
10. What makes a beetle’s metallic shine? **Tiny structures that reflect light.** Stacked thin layers, crystal-like patterns or fine ridges in the shell reflect light. [3]
11. What are a beetle’s elytra? **Hardened front wings.** The elytra are hardened front wings that cover the folded flight wings. [1]
12. When are bronze beetles recorded most often? **Spring and autumn.** Records peak in April–May and again in September–November. [14]

### Sources (checked 2026-10-16)

1. [Liu S, Liu X, Wang X, Li W, Liu X, Ge S (2025). The thoracic anatomy of two flightless Chrysolina species (Coleoptera: Chrysomelidae). Insects 16:618.](https://doi.org/10.3390/insects16060618)
2. [UK Beetle Recording. Chrysolina banksi (Fabricius, 1775): species account.](https://www.coleoptera.org.uk/species/chrysolina-banksi)
3. [Seago AE, Brady P, Vigneron JP, Schultz TD (2009). Gold bugs and beyond: a review of iridescence and structural colour mechanisms in beetles (Coleoptera). Journal of the Royal Society Interface 6:S165–S184.](https://doi.org/10.1098/rsif.2008.0354.focus)
4. [Pasteels JM, Daloze D (1977). Cardiac glycosides in the defensive secretion of chrysomelid beetles: evidence for their production by the insects. Science 197:70–72.](https://pubmed.ncbi.nlm.nih.gov/867051/)
5. [California Department of Food and Agriculture (2022). California Pest Rating Profile for Chrysolina bankii (Fabricius): a leaf beetle. Pest rating C.](https://blogs.cdfa.ca.gov/Section3162/?p=10574)
6. [Petitpierre E (2020). Two new host-plants for Chrysolina bankii (Fabricius, 1775) (Coleoptera: Chrysomelidae). Arquivos Entomolóxicos 22:393–394.](http://www.aegaweb.com/arquivos_entomoloxicos/ae22_2020_petitpierre_two_new_host_plants_chrysolina_bankii_coleoptera_chrysomelidae.pdf)
7. [Gorb EV, Gorb SN (2024). Insect attachment on waxy plant surfaces: the effect of pad contamination by different waxes. Beilstein Journal of Nanotechnology 15:385–395.](https://doi.org/10.3762/bjnano.15.35)
8. [Voigt D, Tsipenyuk A, Varenberg M (2017). How tight are beetle hugs? Attachment in mating leaf beetles. Royal Society Open Science 4:171108.](https://doi.org/10.1098/rsos.171108)
9. [Pizzolante G, Cordero C, Tredici SM et al. (2017). Cultivable gut bacteria provide a pathway for adaptation of Chrysolina herbacea to Mentha aquatica volatiles. BMC Plant Biology 17:30.](https://doi.org/10.1186/s12870-017-0986-6)
10. [University of Minnesota Extension. Colorado potato beetle.](https://extension.umn.edu/yard-and-garden-insects/colorado-potato-beetles)
11. [Termonia A, Hsiao TH, Pasteels JM, Milinkovitch MC (2001). Feeding specialization and host-derived chemical defense in Chrysomeline leaf beetles did not lead to an evolutionary dead end. PNAS 98:3909–3914.](https://doi.org/10.1073/pnas.061034598)
12. [Kuhn J, Pettersson EM, Feld BK et al. (2004). Selective transport systems mediate sequestration of plant glucosides in leaf beetles. PNAS 101:13808–13813.](https://doi.org/10.1073/pnas.0402576101)
13. [Humphreys RK, Ruxton GD (2018). A review of thanatosis (death feigning) as an anti-predator behaviour. Behavioral Ecology and Sociobiology 72:22.](https://doi.org/10.1007/s00265-017-2436-8)
14. [GBIF. Chrysolina bankii (Fabricius, 1775), taxon 4460057: occurrences, vernacular names and IUCN category.](https://www.gbif.org/species/4460057)
15. [Hadjiconstantis M, Zoumides C (2021). First records of the pest leaf beetle Chrysolina (Chrysolinopsis) americana (Linnaeus, 1758) in Cyprus. Biodiversity Data Journal 9:e61349.](https://doi.org/10.3897/BDJ.9.e61349)
16. [Royal Horticultural Society. Rosemary beetle (Chrysolina americana): RHS advice.](https://www.rhs.org.uk/biodiversity/rosemary-beetle)
17. [Garin CF, Juan C, Petitpierre E (1999). Mitochondrial DNA phylogeny and the evolution of host-plant use in Palearctic Chrysolina (Coleoptera, Chrysomelidae) leaf beetles. Journal of Molecular Evolution 48:435–444.](https://doi.org/10.1007/PL00006488)
18. [Jurado-Rivera JA, Petitpierre E (2015). New contributions to the molecular systematics and the evolution of host-plant associations in the genus Chrysolina (Coleoptera, Chrysomelidae, Chrysomelinae). ZooKeys 547:165–192.](https://doi.org/10.3897/zookeys.547.6018)
19. [Bieńkowski AO, Orlova-Bienkowskaja MJ (2018). Alien leaf beetles (Coleoptera, Chrysomelidae) of European Russia and some general tendencies of leaf beetle invasions. PLoS ONE 13:e0203561.](https://doi.org/10.1371/journal.pone.0203561)
20. [iNaturalist. Bronze Beetle (Chrysolina bankii), taxon 318965.](https://www.inaturalist.org/taxa/318965)
21. [Tingle JL, Cook-Patton SC, Agrawal AA (2016). Spillover of a biological control agent (Chrysolina quadrigemina) onto native St. Johnswort (Hypericum punctatum). PeerJ 4:e1886.](https://doi.org/10.7717/peerj.1886)
22. [Mills NJ (2018). An alternative perspective for the theory of biological control. Insects 9:131.](https://doi.org/10.3390/insects9040131)
23. [Suckling DM, Sforza RFH (2014). What magnitude are observed non-target impacts from weed biocontrol? PLoS ONE 9:e84847.](https://doi.org/10.1371/journal.pone.0084847)
24. [Wikidata. Chrysolina bankii (Q1943906).](https://www.wikidata.org/wiki/Q1943906)
25. [Pélissié B, Chen YH, Cohen ZP, Crossley MS, Hawthorne DJ, Izzo V, Schoville SD (2022). Genome resequencing reveals rapid, repeated evolution in the Colorado potato beetle. Molecular Biology and Evolution 39:msac016.](https://doi.org/10.1093/molbev/msac016)

## Measurements & details

- **Size:** 8-10.7 mm
- **Leg Count:** 6

## Diet & Feeding

These beetles are plant-eaters. Adults and larvae chew the leaves of many plants, such as ribwort plantain, mints and thistles.

- **Age differences:** Larvae and adults both feed on the leaves of their host plants.
- **Primary Foods:** Plantago lanceolata, Mentha spicata, Silybum marianum, Lamiaceae plants
- **Foraging Method:** Foraging

## Ecological connections

- **Eaten by:** [Great Tit](https://www.snappit.app/explore/great-tit) (*Parus major*) — Adult beetles are a food source for insectivorous birds.
- **Eaten by:** Garden Cross Spider (*Araneus diadematus*) — Spiders can capture adult beetles in their webs.
- **Eats:** Spearmint (*Mentha spicata*) — The beetles feed on the leaves of spearmint plants.
- **Eats:** [Ribwort Plantain](https://www.snappit.app/explore/ribwort-plantain) (*Plantago lanceolata*) — In Britain the beetles are found especially on ribwort plantain.

## Traits

- [Solitary](https://www.snappit.app/explore/traits/solitary): Solitary animals live alone for most of their lives, only interacting with others for mating or parental care.
- [Colorful](https://www.snappit.app/explore/traits/colorful): Colorful describes organisms or objects displaying a wide range of bright and distinct colors.
- [Herbivorous](https://www.snappit.app/explore/traits/herbivorous): This trait characterizes organisms whose diet consists entirely or primarily of plant material.
- [Diurnal](https://www.snappit.app/explore/traits/diurnal): Diurnal animals are primarily active during daylight hours, typically resting or sleeping at night.
- [Miniature](https://www.snappit.app/explore/traits/miniature): Pertaining to species that are significantly smaller than typical or average for their kind.

## Collections

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

## Safety

**Danger:** 1/5 · Very low

Watch beetles on their plants and do not pick them up. They are easily hurt, and leaf beetles can give off defensive fluids. If you touch one, wash your hands.

## Frequently Asked Questions

### How to identify Bronze 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 Bronze Beetle?

8-10.7 mm

### What does Bronze Beetle eat?

These beetles are plant-eaters. Adults and larvae chew the leaves of many plants, such as ribwort plantain, mints and thistles.

### Where is Bronze Beetle usually found?

Sunny, open places with plantains and mints, often near the coast

### How many legs does Bronze Beetle have?

6

## Where to spot

- [San Juan Bautista State Historic Park](https://www.snappit.app/guides/places/san-juan-bautista-state-historic-park) — California, US · State Park
- [Coast Dairies State Park](https://www.snappit.app/guides/places/coast-dairies-state-park) — California, US · State Park

## 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: [Bronze Beetle: Facts & Places to See — Snappit](https://www.snappit.app/explore/bronze-beetle)