Beetle, scarabaeid

Liquid crystalline behavior occurs in the exocuticle of certain classes of beetles. The bright iridescent colors that are reflected from the surface of Scarabaeid beetles originates from a petrified chiral nematic stmctural arrangement of chitin crystaUites in the exocuticle (38). It is suggested that this chiral nematic texture forms spontaneously in a mobile, Hquid crystal phase that is present during the initial stages of the exocuticle growth cycle. 

Attractive Compounds. Though the first report on the identification of a pheromone from a scarabaeid beetle dates back more than 30 years - phenol as an attractant for males of the gras grub beetle Costelytra zealandica [135] which turned out to be produced by beetle associated bacteria [136] - most of the pheromone structures known today have been elucidated during the last decade [3,137,138]. 

Interestingly, Lepidoptera and aphids seem to avoid already infested plants, whereas Coleoptera are in general attracted to volatiles emitted by plants that are under attack by conspecifics. This has been shown for scarabaeid (Domek and Johnson, 1988 Harari etal., 1994 Loughrin etal., 1995b) and chrysomelid beetles (Peng and Weiss, 1992 Bolter et al., 1997 Kalberer et al., 2001). The Colorado... 

The sex pheromone of the scarabaeid beetle Popillia japonica is a chiral lactone (379) with a (Z)-unsaturated side chain 218). Optically active (/ )(—)-glutamic acid 357, which is converted by retention of configuration via three steps into the Wittig synthon 377, serves as the starting material. Reaction of the latter with the ylide 378 yields the lactone 379 with the desired (R)(Z)-configuration 218) (Scheme 67). 

Some nest parasites in social insects are protected because their cuticular chemistry is very similar to that of the hosts. The complex cuticle hydrocarbon blends of parasite and host are virtually identical and the hosts cannot distinguish the parasites from conspecifics (Stowe, 1988). Nest parasites of the genus Trichopsenius biosynthesize their hydrocarbon mixture the pattern matches the species-specific mixture of their termite hosts. In contrast, the scarabaeid beetle, Myr-mecaphodius excavatacollis, which associates with ants, acquires its hydrocarbons by association with the host and can invade the nests of several different species of ants with different hydrocarbon blends (Stowe, 1988). In another bizarre example, larvae of the neuropteran, Chrysopa slosso-nae, cover themselves with wax plucked from their wax-coated aphid prey. The ants that tend these aphids fail to recognize the neuropterans and do not attack them (Stowe, 1988). 

P. Holter, C. Sommer and J. Gronvold, Attractiveness of dung from ivermectin-treated cattle to Danish and afrotropical scarabaeid dung beetles, Vet. Parasitol., 1993, 48, 159-169. 

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