The bloody-nosed beetle (Timarcha tenebricosa), also called blood spewer or blood-spewing beetle, is a leaf beetle native to Europe.[1][2]

Bloody-nosed beetle
Dorsal view
Lateral view
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Chrysomelidae
Genus: Timarcha
Species:
T. tenebricosa
Binomial name
Timarcha tenebricosa
(Fabricius, 1775)

Description

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T. tenebricosa measures 15–20 mm in length, is blue-black in colour and is both larger and more constricted on the base of its pronotum than the visually similar T. goettingensis (the lesser bloody-nosed beetle).[1][2] The body is strongly curved, and elytra smooth and finely punctuated. Its antennae are thick and well segmented, its legs have long tarsi and terminate with a double hook.

 
Larva

Diet and behaviour

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Timarcha tenebricosa is monophagous; the larvae feed exclusively on bedstraws, especially species with tender leaves (such as Galium verum and Galium mollugo). The adult beetles usually move slowly on the ground, in the grass and herbaceous plants, mainly at night.

As a defensive behaviour, they exude droplets of their bright red-orange hemolymph by breaking thin membranes in their mouth,[3] which is foul-tasting to predators. This phenomenon of reflex bleeding exists in some other insects, such as ladybugs. [4]

Lifestyle

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Eggs are laid in spring on bedstraw. Larvae may measure up to 20 mm and are blue-black in colour. The pupae overwinter.

 
A bloody-nose beetle exuding a drop of noxious red liquid.

Distribution

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The beetle can be found in southern and central Europe, and is common in Britain and Ireland.[2]

References

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  1. ^ a b "Timarcha tenebricosa (Fabricius, 1775)". Coleoptera.org.uk. Retrieved 7 October 2017.
  2. ^ a b c Hubble, D. (2012). Keys to the Adults of Seed and Leaf Beetles of Britain and Ireland. Field Studies Council. p. 53. ISBN 9781908819086.
  3. ^ Robertson, Matthew. "Staying Alive." Insects and spiders. Pleasantville, New York: Reader's Digest Children's Books, 2000. 43.
  4. ^ Knapp, M; Řeřicha, M; Židlická, D (9 June 2020). "Physiological costs of chemical defence: repeated reflex bleeding weakens the immune system and postpones reproduction in a ladybird beetle". Scientific Reports. 10 (1): 9266. Bibcode:2020NatSR..10.9266K. doi:10.1038/s41598-020-66157-9. PMC 7283328. PMID 32518323.
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