Lymexylidae

The Lymexylidae, or ship-timber beetles, 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. Lymexylidae, a wood-boring beetle, possibly first beetles to evolve agriculture. They are fungus farmers of Endomyces hylecoeti and Ascoides spp.

Habitat & Behavior

Symbiotic association: Fungus grows in a sheltered environment 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.

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

There are 37 species in 7 genera, including:

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

Reproduction in Hylecoetus dermestoides

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 make and it is this the young eat rather than the wood. The fungi requires a good flow of air, so the larvae keep their tunnel free of any debris.

Genera

Lymexylidae contains the following genera:

• Arractocetus Kurosawa, 1985
• Atractocerus Palisot de Beauvois, 1801
• Australymexylon Wheeler, 1986
• Elateroides Schaeffer, 1766
• Fusicornis Philippi, 1866
• Lymexylon Fabricius, 1775
• Melittomma Murray, 1867
• Melittommopsis Lane, 1955
• Protomelittomma Wheeler, 1986
• Urtea Paulus, 2004

Morphology

Adult morphology: 5â€"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 (Hylecoetus). 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

Taxonomic & Phylogenetic Classification

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

External links

• L. Watson and M. J. Dallwitz, Lymexylidae
• Lymexylidae on ITIS
• A video of Atractocerus brasiliensis, a ship timber beetle in Costa Rica

See also

• Forest pathology

References

1. ^ 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.
2. ^ Casari, S.A. and Albertoni, F.F., (2013). First Instar Larva of Atractocerus Brasiliensis (Lepeletier & Audinet-Serville, 1825)(Lymexylidae, Atractocerinae). Volume 53(27): 359â€'372.
3. ^ Kundrata, R., Bocakova, M., & Bocak, L. (2014). The comprehensive phylogeny of the superfamily Elateroidea (Coleoptera: Elateriformia). Molecular phylogenetics and evolution, 76, 162-171.
4. ^ 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.
5. ^ Wheeler, Q. D. (1986). Revision of the genera of Lymxylidae (Coleoptera: Cucujiformia). Bulletin of the American Museum of Natural History, 183:113-210.