Lymexylidae

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Ship-timber beetles
Lymexylon navale.jpg
Lymexylon navale
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga
Infraorder: Cucujiformia
Superfamily: Lymexyloidea
Family: Lymexylidae
Fleming, 1821

The Lymexylidae, or ship-timber beetles (historically often spelled Lymexylonidae), are a family of wood-boring beetles, and the sole member of the superfamily Lymexyloidea.

They are 5 to 40 mm long. The larvae bore into living and decaying wood (chestnut, poplar, and oaks) where they eat the fungi that grow in their tunnels (Ascoidea hylecoeti). Lymexylidae are considered to possibly be the first beetles to evolve agriculture.[citation needed]

Habitat and behavior[edit]

Lymexylidae have a symbiotic association with certain types of fungus. The fungus grows in sheltered environments and are tended to by the larvae. In return, the larvae flourish and feed on the fungal farms.

Wood boring activities occur primarily in the larval stage, larvae found in both sapwood and heartwood.

Lymexylon, Elateroides, and Melittomma are pestiferous to forest trees such as Chestnut, Poplar, and Oaks. Some species are pests, killing live trees and damaging timber structures such as houses and ships.

Reproduction in Elateroides dermestoides[edit]

Elateroides dermestoides lays eggs into boreholes of bark beetles on a fallen beech

This species has evolved a very interesting relationship with the yeast-like fungus, Endomyces hylecoeti. Every egg the female lays is coated with fungal spores from a pouch near her ovipositor. The larvae hatch and collect some of the spores by staying close to their egg shells for a while before tunnelling into the wood. The fungi grows on the walls of the tunnel the larvae makes and it is what the larvae consume rather than the wood itself. The fungi requires a good flow of air, so the larvae keep their tunnel free of any debris.[1]

Species and Genera[edit]

There are nearly 50 species in 8 genera, including:

  • The ship timber beetle, Lymexylon navale
  • 2 species located in Eastern US and Canada: the sapwood timberworm Elateroides lugubris (Say) and the chestnut timberworm, Melittomma sericeum

Lymexylidae contain the following genera:[2]

Morphology[edit]

Adult morphology:

  • 5–40 mm long; elongate to slender, parallel-sided, vestiture consisting of fine setae; conspicuously necked to not necked; somewhat waisted.
  • Head short, typically narrowed behind large protruding eyes forming a slight neck; surface punctate, with or without epicranial pit.
  • Antennae short 11-segmented, filiform/serrate, often sexually dimorphic.
  • Maxillary palpi 4-segmented, simple in most females, and with apical segment modified into a complex flabellate or plumose organ in males-palporgan.
  • Tarsi 5-5-5 with legs slender, moderately long.
  • Hind-leg coxae extending laterally to meet the elytra (Lymexylon), or not markedly extended laterally (Elateroides).
  • Elytra individually tapered to their apices to not individually tapered; fairly short, exposing several terminal abdominal 1-3 tergites; all articulated and moveable.
  • Wings with fairly complete venation, radial cell short or absent

Immature Morphology:

  • Whitish-yellow, elongate, thin, cylindrical with short but well developed legs.
  • Prognathous, stemmata absent or present, may have eye spots.
  • Abdominal modifications found in older larvae.

Classification[edit]

The Superfamily Lymexyloidea is currently within Series Cucujoidea. The internal phylogeny has not been clearly understood/completed by experts. Morphological data puts it inside Tenebrionoidea, and molecular data as sister to Tenebrionoidea, and polyphyletic.

See also[edit]

Notes[edit]

  1. ^ Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press.
  2. ^ Lymexylidae Species List at Joel Hallan’s Biology Catalog. Texas A&M University. Retrieved on 17 May 2012.

References[edit]

  • Arnett, Ross H., et al., eds. American Beetles: Polyphaga: Scarabaeoidea through Curculionoidea. Vol. 2. CRC Press, 2002: 261-262. EBSCO printed on Sept. 21,2013.
  • Casari, S.A. and Albertoni, F.F., (2013). First Instar Larva of Atractocerus brasiliensis (Lepeletier & Audinet-Serville, 1825) (Lymexylidae, Atractocerinae). Volume 53(27): 359‑372.
  • Kundrata, R., Bocakova, M., & Bocak, L. (2014). The comprehensive phylogeny of the superfamily Elateroidea (Coleoptera: Elateriformia). Molecular phylogenetics and evolution, 76, 162-171.
  • Triplehorn, Charles A., Norman F. Johnson, and Donald J. Borror. Borror and DeLong's Introduction to the Study of Insects. Belmont, CA: Thompson Brooks/Cole, 2005.
  • Wheeler, Q. D. (1986). Revision of the genera of Lymexylidae (Coleoptera: Cucujiformia). Bulletin of the American Museum of Natural History, 183:113-210.

External links[edit]