Diachus auratus (Fabricius)

Clark, Shawn M., Lillrose, Tiffany & Belo Neto, Luiz A., 2013, Leaf Beetles of the Cayman Islands (Coleoptera: Chrysomelidae), Insecta Mundi 2013 (279), pp. 1-41 : 35-36

Diachus auratus (Fabricius)

( Figure 30)

Cryptocephalus auratus Fabricius 1801b: 57 .

Eumolpus aeneus Olivier 1808: 916 .

Cryptocephalus chalconatus Mannerheim 1843: 312 .

Monachus viridis Melsheimer 1847: 174 .

Diachus aeneolus LeConte 1880: 197 [nomen nudum].

Melixanthus hisamatsui Takizawa 1975: 56 .

Diagnosis. The subcylindrical body shape and small body size (normally less than 2 mm long) are sufficient to distinguish this species from all other chrysomelids known to occur in the Cayman Islands. The appendiculate, rather than simple, tarsal claws further distinguish it from the genus Cryptocephalus that shares many of the same characteristics. The dorsal color is mostly dark brown, the pronotum being somewhat paler than the elytra and with yellowish lateral margins, and the surface is strongly alutaceous. The eyes are more than twice as long as broad. Triachus cerinus LeConte is a cryptocephaline chrysomelid that is widespread in the West Indies. It has not yet been found in the Cayman Islands but may eventually be discovered there. It is even smaller than D. auratus , the color is mostly yellow, the surface is strongly polished, and the eyes are nearly round.

Material examined. Cayman Islands, Grand Cayman , Georgetown, UCCI, 19-V-2009, M. Thomas (1, FSCA) ; Cayman Islands, Grand Cayman, Governor Gore’s Pond , 28-V-2009, R. Turnbow (1, RHTC) .

Extralimital distribution. This species is widespread throughout much of the New World, and it has spread to many localities in the Old World ( Riley et al. 2003).

Plant associations. This species has been associated with numerous plants in diverse plant families ( Clark et al. 2004).

Comments. As a whole, the genus Diachus is in need of taxonomic study. Within the genus, D. auratus seems to be quite distinctive, but future study may reveal that there is actually a complex with several cryptic species.