Carpophilus

Attractive Compounds. The male-produced pheromones of sap beetles, known so far, show the rather stereotypic structures 125-147 (Scheme 15) methyl- and ethyl-branched hydrocarbons with three or four (T)-configured conjugated double bonds [4]. Up to now, 23 compounds could be identified, forming species specific mixtures. Major components in the bouquets are (2E,4E,6E)-5-ethyl-3-methyl-2,4,6-nonatriene, 128, in Carpophilus davidsoni [268] as well as in C.freemani [269], (2 ,4 ,6 )-4,6-dimethyl-2,4,6-nonatriene, 129,in C. truncatus [270], (3 ,5 ,7 )-5-ethyl-methyl-3,5,7-undecatetraene, 132, in C. mutillatus [271],(2 ,4 ,6 ,8 )-3,5,7-trimethyl-2,4,6,8-decatetraene, 134,in C. hemipterus [272] as well as C. brachypterus [273], (2 ,4 ,6 ,8 )-3,5,7-tri-... 

Bartelt, R. J. and Weisleder, D. (1996). Polyketide origin of pheromones of Carpophilus davidsoni and C. mutilatus (Coleoptera Nitidulidae). Bioorganic and Medicinal Chemistry 4 429 138. 

Nardi J. B., Dowd P. F. and Bartelt R. J. (1996) Fine structure of cells specialized for secretion of aggregation pheromone in a nitidulid beetle Carpophilus freemani (Coleoptera Nitidulidae). Tissue Cell 28, 43-52. 

Figure 6.6 Structures of 2,3-dihydro-2,3,5-trimethyl-6-(1 -methyl-2 -oxobutyl)-4H-pyran-4-one (stegobinone), pheromone of Stegobium paniceum (L.) (Anobiidae) (Kuwahara et al., 1978) and (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-decatetraene, pheromone component of Carpophilus hemipterus (L.) (Nitidulidae) (Bartelt et al., 1991). The carbon skeletons are identical, and likely derived through similar pathways (see text).

The assembly of the carbon skeletons of these unusual hydrocarbons was first studied in Carpophilus freemani Dobson, through careful GC-MS and Nuclear Magnetic Resonance (NMR) studies of the incorporation of 2H or 13C-labeled precursors (Petroski et al., 1994). Assembly of the carbon skeleton of the aggregation pheromone of C. freemani, (2 , 4 , 6ii)-5-ethyl-3-methyl-2,4,6-nonatriene, involves initiation with acetate elongation with first propionate (to provide the methyl branch), then butyrate (to provide the ethyl branch) and chain termination with a second butyrate (Figure 6.7). At some point, loss of C02 from one of the butyrate units occurs to yield the appropriate hydrocarbon, but Petroski et al. (1994) were unable to determine which of the butyrate units loses its carboxyl group. Bartelt and Weisleder (1996) studied the biosynthesis of 15 additional methyl- and/or ethyl-branched, tri- and tetraenes in the related... 

Bartelt R. J., Dowd P. F. and Plattner R. D. (1991) Aggregation pheromone of Carpophilus lugubris new pest management tools for the nitidulid beetles. In Naturally Occurring Pest Bioregulators, ed P. A. Hedin, pp. 27 -0. ACS Symposium Series No. 449, American Chemical Society, Washington, DC. 

Petroski R. J. and Vaz R. (1995) Insect aggregation pheromone response synergized by host type volatiles. Molecular modeling evidence for close proximitiy binding of pheromone and coattractant in Carpophilus hemipterus (L.) (Coleoptera Nitidulidae). In Computer-Aided Molecular Design, eds C. H. Reynolds, M. K. Holloway and H. K. Cox, pp. 197-210. ACS Symposium Series 589, American Chemical Society, Washington, DC. 

Petroski R. J., Bartelt R. J. and Weisleder D. (1994) Biosynthesis of (2 ,4 ,6 )-5-ethyl-3-methyl-2,4,6-nonatriene the aggregation pheromone of Carpophilus freemani (Coleoptera Nitidulidae). Insect Biochem. Molec. Biol. 24, 69-78. 

Chapter 19 by Bartelt is devoted to the pheromonal role of short-chain hydrocarbons, especially short i n etli y l/etli y I - branched and unsaturated components in beetles. The most abundant components in Carpophilus hemipterus (Coleoptera, Nitidulidae) have been identified as (2/ ,4/ ,6/ ,8/ )-3,5,7-(rimc(hyl-2,4,6,8-decatetracnc and (2E,4E,6E,SE)-3,5,7-trimethyl-2,4,6,8-undecatetraene (Bartelt et al., 1990). Later studies showed that male C. hemipterus emit nine all-E tetraene hydrocarbons and one all-E triene hydrocarbon in addition to the two previously reported pheromonally active tetraenes (Bartelt et al., 1992). In their review of biologically active compounds in beetles, Francke and Dettner (2005) fisted only a few dozen of those pheromonal compounds, most of which were identified by Bartelt. 

Bartelt, R. J., Weisleder, D., Dowd, P.F. and Plattner, R.D. (1992). Male-specific tetraene and triene hydrocarbons of Carpophilus hemipterus Structure and pheromonal activity. J. Chem. Ecol., 18, 379 102. 

Hinton (1945) and Connell (1956,1991). Williams et al. (1983) compiled a useful bibliography for Carpophilus. 

Effects of pheromone dose on trap catch have been studied. The usual amount of pheromone per septum was 500 pg. In California, all doses of Ca. hemipterus pheromone from 15 to 15 000 pg per septum were significantly active in the field, and for Ca. mutilatus, all doses from 50 to 15 000 pg were active (Bartelt et al., 1994a). Attractiveness increased with pheromone dose throughout the range for both species. Similar trends were noted for these species in Australia when 500 - and 5000 -pg doses were compared (James et al., 1994). With Carpophilus beetles, high pheromone doses never became repellent. 

The most intensive effort to use pheromones in insect management has been in Australia, where an attract-and-kill strategy has been developed for protecting stone fruit crops. Historically, the Oriental fruit moth, Grapholita molesta Busck, was the major stone fruit pest, and heavy insecticide applications kept both this moth and, coincidentally, the Carpophilus beetles at acceptable levels. However, the widespread adoption of pheromone-based mating disruption for G. molesta control released the Carpophilus beetles from insecticide pressure, and these beetles, Ca. davidsoni in particular, became the dominant stone fruit pests (James et al., 1994). Late applications of broad-spectrum insecticides often... 

Bartelt, R. J Dowd, P.F., Shorey, H.H. and Weisleder, D. (1990b). Aggregation pheromone of Carpophilus freemani (Coleoptera Nitidulidae) a blend of conjugated triene and tetraene hydrocarbons. Chemoecology, 1,105-113. 

Bartelt, R. J., Dowd, P. F., Vetter, R. S., Shorey, H. H. and Baker, T. C. (1992a). Responses of Carpophilus hemipterus (Coleoptera Nitidulidae) and other sap beetles to the pheromone of C. hemipterus and host-related coattractants in California field tests. Environ. Entomol., 21,1143-1153. 

Bartelt, R. J. and Hossain, M. S. (2006). Development of synthetic food-related attractant for Carpophilus davidsoni and its effectiveness in the stone fruit orchards in southern Australia../. Chem. Ecol., 32, 2145-2162. 

Bartelt, R. J., Kyhl, J. F Amboum, A.K., Juzwik, J. and Seybold, S. J. (2004). Male-produced aggregation pheromone of Carpophilus sayi, a nitidulid vector of oak wild disease, and pheromonal comparison with Carpophilus lugubris. Agric. For. Entomol., 6, 39—46. 

Carpophilus antiquus (Coleoptera Nitidulidae) and kairomonal use of C. lugubris pheromone by C. antiquus. J. Chem. Ecol., 19, 2203-2216. 

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