Desmocerini Blanchard, 1845

The monotypic tribe Desmocerini was erected by Blanchard (1845) to hold the North American genus Desmocerus, the species of which bore exclusively into the living roots and stems of elderberry (Sambucus). Although originally isolated for its relatively short maxillary palps, modern systematists have maintained Desmocerini primarily based on the structure of the Desmocerus mandibles, which are broad and lack the internal pubescent fringe common to the rest of the Lepturinae. Desmocerini was recognized by North American authors beginning with LeConte (1873), and followed by LeConte and Horn (1883), Leng (1890), Boppe (1921), Linsley (1940), Arnett (1962), Linsley and Chemsak (1972) and Arnett et al. (2002), among others. Some authors have treated Desmocerus within the Dorcosomini (e.g., Lacordaire, 1869, Bradley, 1930; Saalas, 1936; and Dillon and Dillon, 1961), however Dorcasominae Lacordaire, 1869 is now considered a separate subfamily in the Cerambycidae (see Özdikmen, 2008).

The unique mouthparts of Desmocerus are probably due the divergence of the genus’ life history habits from those of the typical flower-visiting lepturines. Although emergence of Desmocerus adults in the summer is often coordinated with the blooming of its species-specific elderberry host plants, and despite the hefty racemes of the Sambucus apparently being palpable to other lepturine genera (see Bond and Philips, 1999), the adult lives of Desmocerus species are spent on the leaves of the elderberry plants. The relatively sedentary adult females are occasionally observed to feed on leaves, but never the flowers, and no reports exist for males feeding at all.

    
Fig. 1. An early plate by Cuvier et al. (1836), shows the mandibles and palpi of Desmocerus palliatus compared to several other lepturines, demonstrating the lack of internal pubescent fringe.

The primary utility of Desmocerini seems to be as an indicator that there is still not enough information available to confidently assess the evolutionary relatedness of Desmocerus to its lepturine relatives worldwide. The structure of the pronotum in Desmocerus, which is expanded at the base with pointed lateral angles, suggests an affinity with the Lepturini, and this has been at least partially supported by a recent phylogenetic analysis of the Lepturinae by Sýkorová (2008), albeit with just one gene, mitochondrial 16s rDNA, from a single specimen of D. palliatus.  Another notable feature is the first tarsal segment of the hind leg, which is stout with a thick pubescent sole, a common feature of the Rhagiini. In their review of the cerambycoid larvae of Europe and the Soviet Union, Švácha and Danilevsky (1989) remark (p.15) that Desmocerus is "undoubtedly" part of Rhagiini based on a shared unique larval character with Pseudogaurotina  (see also Švácha and Danilevsky 1986, pp. 14-15), in addition to the shared life history traits of the two genera, which both bore into living wood.

References

1. Arnett, R. H. 1962. The beetles of the United States. 1112 pp. Univ. Amer. Press, Washington, D.C.
2. Arnett, R. H., C. T. Michael, P. E. Skelly, and J. H. Frank. 2002. American Beetles. Volume 2. Polyphaga: Scarabaeoidea through Cuculionoidea. CRC Press. Washington, D.C.
3. Blanchard, C.E. 1845. Histoire des insectes, traitant de leurs moeurs et de leurs métamorphoses en général, et comprenant une nouvelle classification fondée sur leurs rapports naturels.2:163. <http://archive.org/details/histoirenaturell02blan> <PDF> <p.163>
4. Bond, W.B. and T.K. Philips. 1999. Diversity, phenology, and flower hosts of anthophilous long-horned beetles (Coleoptera: Cerambycidae) in a southeastern Ohio forest. Entomological News. 110: 267-278. 
5. Boppe, P. L. 1921. Genera insectorum, fam. Cerambycidae: subfam. Disteniinae Lepturinae, fasc. 178, 119 pp., 8 pls. 
6. Bradley, J. C. 1930. A manual of the genera of beetles of America north of Mexico. Ithaca, New York. 360 pp. 
7. Cuvier, G., 1836. Le règne animal distribué d'après son organisation,pour servir de base à l'histoire naturelle des animaux, et d'introduction à l'anatomie compare. v. 6-7. Pt. 1. Atlas. Paris :Fortin, Masson et cie,[1836-49].
8. Dillon, L. S. and E. S. Dillon. 1961. A manual of common beetles of eastern North America. 884 pp. Evanston, Ill., Row Peterson. 
9. Lacordaire, T. 1869. Histoire Naturelle des Insectes. Genera des coléoptères, vol. 8, 552 pp.
10. LeConte, J. L. 1873. Classification of the Coleoptera of North America. Prepared for the Smithsonian Institution. Part II. Smithsonian Miscellaneous Collections.  11(265): 279-348. <Biodiversity Heritage Library> 
11. LeConte, J. L. & G. H. Horn. 1883. Classification of the Coleoptera of North America. Prepared for the Smithsonian Institution. Smithson. Misc. Coll’ns., 26(507): xxxvii + 1-567.
12. Leng, C. W. 1890. Synopses of Cerambycidae. Entomol. Amer., 6: 9-13, 65-69, 97-98, 104-110, 156-160, 185-200, 213-214. 
13. Linsley, E. G. 1940. A revision of the North American Necydalini (Coleoptera, Cerambycidae). Ann. Entomol. Soc. Amer., 33: 269-281. 
14. Linsley, E. G., and J. A. Chemsak. 1972. Cerambycidae of North America. Part VI. No. 1. Taxonomy and Classification of the Subfamily Lepturinae. University of California Publications in Entomology 69,  xiii+138 pp, 2 pl.
15. Özdikmen, H. 2008. A nomenclatural act: Some nomenclatural changes on Palaearctic Longhorned beetles (Coleoptera: Cerambycidae). Munis Entomology & Zoology 3 (2): 707- 715
16. Saalas U., 1936 - Über das Flügelgeäder und die phylogenetische Entwicklung der Cerambyciden - Annales Zoologici Societatis Zoologicae-Botanicae Fennicae Vanamo 4 (1): 1-193.Švácha P. and Danilevsky M.L., 1986. Cerambycoid larvae of Europe and Soviet Union (Coleoptera, Cerambycoidea). Part I. Acta Univ. Carolinae, 30, 1-176. PDF.
17. Švácha P. and Danilevsky M.L., 1989. Cerambycoid larvae of Europe and Soviet Union (Coleoptera, Cerambycoidea). Part III. Acta Univ. Carolinae, 32, 1-2: 1-205. PDF.
18. Sýkorová, M. 2008. Molecular phylogeny of the subfamilies Spondylidinae and Lepturinae (Coleoptera: Cerambycidae) based on mitochondrial 16S rDNA. Bachelor’s thesis, Faculty of Natural Sciences, South Bohemian University, Ceske Budejovice.