The Cerambycidae (longhorned, capricorn, or timber beetles) are a strictly herbivorous beetle group that predominantly spends its immature phase feeding inside plants. This family is morphologically diverse, but most species do have antennaeantenna:
in larval and adult insects, paired segmented appendages, borne one on each side of the head, functioning as sense organs and bearing a large number of sensilla
that are close to or exceeding the body length and arise on tubercles. There are usually five tarsomeres on each leg, with the fourth often much smaller, and some genera (like Monochamus) have tarsomeres 4+5 completely fused. The larvae, called roundheaded borers, are also very anatomically diverse but are most often pale-colored and elongateelongate:
much longer than wide
with an obvious head. The larval pronotal region is not much wider than the rest of the thoraxthorax:
the middle body segment in insects which bears the legs and wings, consists of the pro-, meso-, and meta- thorax
, in contrast to the often co-occurring Buprestidae which have a flattened wide pronotum.
The family Cerambycidae includes seven subfamilies (Svacha and Lawrence 2014Svacha and Lawrence 2014:
Svacha, P. amp; J.F. Lawrence. 2014. 2.1 Vesperidae Mulsant, 1839; 2.2 Oxypeltidae Lacordaire, 1868; 2.3 Disteniidae J. Thomson, 1861; 2.4 Cerambycidae Latreille, 1802. In Leschen R.A.B. amp; Beutel R. G. (eds.): Handbook of Zoology, Arthropoda: Insecta; Coleoptera, Beetles, Volume 3: Morphology and systematics (Phytophaga). Walter de Gruyter, Berlin/Boston, 16-177 pp.; Nie et al. 2020): Prioninae, Parandrinae, Spondylidinae, Lepturinae, Dorcasominae, Cerambycinae, and Lamiinae. As of 2023, there are 36,284 species, and 5063 genera (Titan database: http://titan.gbif.fr/). In the New World, 1,974 genera are recorded (http://bezbycids.com), with 908 in the Palearctic region (Danilevsky 2022: http://www.cerambycidae.net/catalog.pdf). The Cerambycidae are found worldwide and are more species rich in the tropics, especially the subfamily Lamiinae. However, the Lepturinae has a bipolar distribution being seemingly outcompeted in the tropics by other insects feeding in moist decaying wood. The larvae of cerambycids feed predominantly under bark and within the sap- and heartwood of living and dead woody plants, several are also known to feed in grasses and forbs. Larval feeding habits leave tunnels and pupal chambers in plants that are often diagnostic at the genus level.
There are several other beetle groups that are superficially similar to the Cerambycidae. The Anthribidae, Oedemeridae, Chrysomelidae, Cantharidae, and Stenotrachelidae can have a similar body shape and/or long antennaeantenna:
in larval and adult insects, paired segmented appendages, borne one on each side of the head, functioning as sense organs and bearing a large number of sensilla
. They are often found in similar environments as adults. The larvae of Oedemeridae, Stenotrachelidae, and Anthribidae can also be found in wood but have an exsertedexserted:
projecting; thrust forth
or protracted head, while the Cerambycidae mostly have the head extensible and retracted into the prothorax, except for the Lepturinae which have well-developed legs. See LongicornID if you need to confirm that you have a cerambycid.
To properly view all morphological characters, especially in small specimens, a dissecting scope with optics to 40x and a good light source are necessary. An eyepiece-based measuring device will help in measuring characters like antennomeresantennomere:
a subunit of the antenna, including the scape, pedicel, and flagellomeres
. In some cases, access to a DNA sequencing facility will be necessary, primarily to identify improperly eclosed specimens and larvae.
This tool allows for the identification of all known conifer-feeding genera of subfamilies Lamiinae, Cerambycinae, and Spondylidinae in the northern hemisphere. Some genera of other subfamilies are included if they have been intercepted in the USA. Our genetic data is not comprehensive but it does include common intercepts and many genera absent in public databases. If a specimen does not match any of the included genera, confirm first that it came from a conifer, and if yes, then it is possible that it is a new record for the region. This happens more often with decomposed wood feeders which would not be in solid packaging. If not from a conifer, this tool provides more of a starting point with high potential for diagnosing the usual suspects. If you think you possess a new record, please contact one of the content authors.
In addition to conifer feeding species, a key is provided to critical invasive genera from all host plant classifications. This key is to adults and larvae that have regularly been intercepted in the USA over the past 30 years (Haack 2006Haack 2006:
Haack, R.A. 2006. Exotic bark- and wood-boring Coleoptera in the United States: recent establishments and interceptions. Can. J. For. Res. 36, 269-288. https://doi.org/10.1139/X05-249, Eyre and Haack 2017Eyre and Haack 2017:
Eyre, D., R.A. Haack, 2017. Invasive Cerambycid Pests and Biosecurity Measures, in: Wang, Q. (Ed.), Cerambycidae of the World: Biology and Pest Management. Taylor amp; Francis, Boca Raton, pp. 563-607.; USDA APHIS personal communication). Most of these genera are also included in the genetic data for COI and CAD genes. Beyond the genera treated, others have been intercepted at low rates, and thousands more have the potential to invade, so confirm any identifications made.
In addition to the species level key to Monochamus, this tool can be used to identify some additional species. This can occur if the DNA sequences are queried, and a very close match (>99%COI)is made to a species in the database. Each sequence is derived from an individual species, and some genera have multiple species included in the dataset. Therefore, in some cases a species level identification can be made. Unfortunately, not all Holarctic genera can be separated into monophyletic groups, so a native vs. non-native distinction cannot be made at the genus level except in select genera like Monochamus and Megasemum.
