H. C. Coppel

Trail-following pheromones of the rhinotermitidae: Approaches to their authentication and specificity

A method for determining the authenticity of subterranean termite trail pheromones is suggested and utilized to verify the presence of trail pheromones inReticulitermes virginicus, R. flavipes, andR. tibialis. In addition, a possible trail pheromone has been demonstrated forCoptotermes formosanus. A choice bioassay method shows that the above trail pheromones are species specific.

Identification of ant repellent allomone produced by social waspPolistes fuscatus (Hymenoptera: Vespidae)

Two active components were isolated from the ant repellent secretion produced by glandular cells on the sixth (terminal) gastral sternite ofPolistes fuscatus (F.) females. One of the components was identified as methyl palmitate. Field bioassays with synthetic methyl palmitate showed it had repellent activity againstSolenopsis geminata (F.)Forelius pruinosus (Roger), andPheidole sp. The effectiveness of the repellent was greater againstF. pruinosus andPheidole sp. than againstS. geminata. Four methyl ester homologs of methyl palmitate also were field tested for repellent activity: methyl myristate had repellent activity against all three ant species, whereas methyl stearate, methyl linoleate, and methyl linolenate exhibited no repellency.

Chiral specificity of the sex pheromone of the red-headed pine sawfly,Neodiprion lecontei

The stereospecificity of the sawfly pheromone 3,7-dimethyl-2-pentadecanol acetate againstNeodiprion lecontei was studied. Twoerythro and a 1∶1 mixture ofthreo isomers (C-2 and C-3) were synthesized for this purpose. It was found that only one isomer with (−)-erythro configuration (2S, 3S) had biological activity. The potency of this synthetic pheromone was roughly identical to the one shown by the naturally occurring pheromone in this species.

Synthetic analogues of the termite trail-following pheromone, structure and biological activity

Abstract Several synthetic analogues of the trail-following pheromone of a southern subterranean termite, Reticulitermes virginicus, were prepared to study the structural basis of the biological activity of the pheromone in this species. It appeared from the results of comparison that the pheromone-mimicking compounds owe their activities to two strategically situated cis or equivalent double bonds, adjacent to the hydroxy end of the alcohol to form a ∪-shape. Any deviation from this form or the lack of suitable double bonds results in a loss of the activity.

Preparation and use of sex attractants for four species of pine sawflies

Sex attractants were prepared for four species of diprionid sawflies,Neodiprion lecontei, N. swainei, N. sertifer, andDiprion similis, by esterification of both synthetic and naturally occurring alcohols. For the first two species totally synthetic (racemic) compounds were attractive to males in the field. For the latter two species, none of the synthetic compounds tested were consistently attractive. For these, effective attractants were prepared by saponification and reesterification of crude extracts from female insects.

Field evaluation of chiral isomers of the sex pheromone of the european pine sawfly,Neodiprion sertifer

Among optical isomers of 3,7-dimethylpentadecan-2-ol (diprionol) acetate or propionate tested as synthetic attractants, the 2S, 3S, and 7S isomers were most effective in attracting the males ofNeodiprion sertifer in the field. The 2S, 3S, and 7R isomers showed weak activity, but the other optical isomers were not attractive. Capillary GC analysis showed that the natural pheromone from body extracts of females was identical with the synthetic acetate of diprionol in its GC behavior. However, the natural pheromone was about 100-fold stronger than the most purified synthetic acetate of 2S,3S,7S-diprionol in the field. As a result of various isomer combination studies, it was found that the acetate of 2S,3R,7R-diprionol, when added to 2S,3S,7S-diprionol preparation at a low concentration, increased the catch by the latter. It was therefore concluded that the above combination of the optical isomers could account for the major sex attractancy in this species.

The susceptibility of Reticulitermes flavipes (Kollar) and other termite species to an experimental preparation of Bacillus thuringiensis Berliner

Abstract An experimental soluble toxin preparation derived from Bacillus thuringiensis Berliner is toxic to Reticulitermes flavipes (Kollar), Reticulitermes virginicus (Banks), Reticulitermes hesperus Banks, and Zootermopsis angusticollis (Hagen). Approximately 75 percent mortality is achieved by the soluble factor after 9 days. The soluble toxin in combination with spores and inclusion bodies results in greater than 90 percent mortality.

Field response and gas-liquid chromatograph separation of optically active synthetic and natural pheromones in two sympatric diprionid sawflies,Neodiprion nanulus nanulus andNeodiprion sertifer (Hymenoptera: Diprionidae).

The male red pine sawflyNeodiprion nanulus nanulus Schedl responds mainly to the (2S,3S,7S)-3,7-dimethylpentadecan-2-yl acetate (2S,3S,7S-A) in the field. No other isomer is as effective by itself or syner-gizes 2S,3S, 7S-A in this species. ForNeodiprion sertifer (Geoffroy), however, we confirmed our earlier report that males responded significantly to a 5∶0.003 mixture of 2S,3S,7S-A and either 2S,3R,7R-A or 2S,3R,7R/S-A. The 2S,3S,7S-A isomer was separated from 2S,3R,7R-A by capillary gas-liquid chromatographic (GLC) analysis using Carbowax 20 M and DB-5 columns. The latter column also separated 2S,3S,7S-A from 2S,3R,7S-A. Only 2S,3S,7S-A was found in the natural pheromones ofN. n. nanulus andN. sertifer by GLC analysis.

Pheromone-dependent species recognition mechanisms betweenNeodiprion pinetum andDiprion similis on white pine.

The sex pheromones ofNeodiprion pinetum (Norton) andDiprion similis (Hartig) consist of two isomers, 2S,3S,7S and 2S,3R,7R, in either the acetate orpropionate forms of 3,7-dimethylpentadecan-2-ol, respectively. The 2S,3S,7S acetate isomer is utilized byN. pinetum as the major pheromone component and the 2S,3R,7R acetate as a Synergist. ConverselyD. similis utilizes 2S,3R,7R as propionate the major pheromone component and 2S,3S,7S propionate as a Synergist. This was confirmed in the field in both Michigan and Wisconsin. Capillary gas-liquid chromatographie analyses revealed that these two isomers are present in the natural pheromones of both species at the ratios close to those predicted by artificial blending of the two optical isomers.

Field attractiveness of chirally defined synthetic attractants to males ofDiprion similis andGilpinia frutetorum

Field attractiveness of synthetic attractants toward males of two introduced species of sawflies was examined. It was first established that the esters of 2S,3S,7S-3, 7-dimethylpentadecan-2-ol (diprionol), which have been active toward males of manyNeodiprion species, were inactive toward males ofDiprion similis andGilpinia frutetorum, To determine the chiral combination of the alcohol moiety, four different isomers, each containing specific chirally defined carbons, were synthesized. As a result it was concluded that the most active chiral arrangement of diprionol for these species is 2S, 3R, 7R.