Abner M. Hammond

Trapping Phyllophaga spp. (Coleoptera: Scarabaeidae: Melolonthinae) in the United States and Canada using sex attractants.

Abstract The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified. Three major findings included: (1) widespread use of the two compounds [of the 147Phyllophaga (sensu stricto) species found in the United States and Canada, males of nearly 40% were captured]; (2) in most species intraspecific male response to the pheromone blends was stable between years and over geography; and (3) an unusual pheromone polymorphism was described from P. anxia. Populations at some locations were captured with L-valine methyl ester alone, whereas populations at other locations were captured with L-isoleucine methyl ester alone. At additional locations, the L-valine methyl ester-responding populations and the L-isoleucine methyl ester-responding populations were both present, producing a bimodal capture curve. In southeastern Massachusetts and in Rhode Island, in the United States, P. anxia males were captured with blends of L-valine methyl ester and L-isoleucine methyl ester. Resumen La feromona sexual del escarabajo, Phyllophaga anxia, es una mezcla de los ésteres metílicos de dos aminoácidos, L-valina y L-isoleucina. Se condujo un estudio de campo usando diferentes mezclas de los dos componentes en 59 sitios de Estados Unidos y Canada. Más de 57,000 machos de 61 especies dePhyllophaga fueron capturados e identificados. Tres de los resultados más importantes incluyen: (1) el extenso uso de los dos componentes [de las 147 especies de Phyllophaga (sensu stricto), en Estados Unidos y Canada, fueron capturados machos de cerca del 40% de ellas.]; (2) para la mayoría de las especies, la respuesta intraespecífica de los machos a las combinaciones de los dos aminoácidos fue consistente entre años diferentes, y en todos los sitios geográficos; y (3) un inusual polymorfismo de la feromona fue descrito para P. anxia. Poblaciones de algunos sitios fueron atrapados sólo con valina, mientras que poblaciones de otros sitios fueron atrapados sólo con isoleucina. También se encontraron sitios donde las poblaciones responden a ambos componentes, valina e isoleucina, produciendo una curva de captura bimodal. En el sureste del estado de Massachusetts y en Rhode Island, en Estados Unidos, machos de P. anxia fueron atrapados en trampas con mezclas de valina e isoleucina.

Specificity of male response to multicomponent pheromones in noctuid mothsTrichoplusia ni andPseudoplusia includens.

The response of male cabbage looper (CL) and soybean iooper (SBL) moths was observed in the flight tunnel and measured in field tests to the six-component CL pheromone, the five-component SBL pheromone, and toZ7–12: OAc, the major component common to each pheromone. In both the flight tunnel and the field, male CL exhibited significantly greater levels of response to their six-component blend than toZ7–12: OAc alone. A low level of cross-attraction of male CL to the SBL pheromone was observed in both the flight tunnel and the field, but it was quantitatively and qualitatively similar to their response toZ7–12: OAc alone. Thus the minor components of the SBL blend did not appear to disrupt the flight behavior of male CL. With respect to SBL, in the flight tunnel males also exhibited a greater level of response to the five-component blend compared toZ7–12: OAc, but in the field their response was not significantly different to either treatment. There was also a low level of cross-attraction of male SBL to the CL blend, but this appeared to involve a significant arrestment effect on the upwind flight of males, as well as a difference in male sensitivity to the blend of components compared withZ7–12: OAc alone. The observed arrestment effect may have been due to male perception of one or more minor components of the CL pheromone. The results show that the multicomponent pheromones of these species function effectively as specific mating signals and that discrimination of odor quality by male moths can occur as the result of minor components affecting male sensitivity or their upwind flight response to the pheromone.

Purification and kinetics of juvenile hormone esterase from the cabbage looper, Trichoplusia ni (Hubner)

Abstract A method for purifying juvenile hormone esterase from the haemolymph of Trichopulsia ni (Hubner) was developed. The procedure resulted in a single protein band when electrophoresed on SDS-polyacrylamide gels. The enzyme consisted of a single polypeptide chain of mol. wt 48,000 as determined by gel electrophoresis and gel filtration chromatography. Enzyme activity was stable in 40% sucrose for more than 5 months, and unstable when exposed to charged environments at low enzyme concentration. The enzyme possessed apparent K m values of 1.13 × 10 −6 and 0.402 × 10 −6 M for JH I and JH III, respectively.

Characterization of the plasma juvenile hormone esterase in synchronous last stadium female larvae of the sugar cane borer, Diatraea saccharalis (F.)

Abstract A peak in the plasma juvenile hormone esterase (JHE) activity occurred near the time when female last stadium sugar cane borers reached their maximum weight, and a second peak of plasma JHE activity and a peak in the plasma α-naphthyl acetate esterase (α-NAE) activity occurred at the prepupal stage. Two JHEs were resolved by high pressure liquid chromatography (HPLC), gel filtration, and isoelectric focusing. Their apparent mol. wts were 40,000 and 34,000 and their isoelectric points 6.9 and 6.3. Juvenile hormone I was metabolized by JHE at about twice the rate of JH III. The apparent K m of prepupal JHE and the V max were also greater for JH I (3.29 μM and 8.38 nM min−1 ml−1, respectively) than for JH III (3.04 μM and 3.75 nM min−1 ml−1, respectively). The last stadium JHE and α-NAE activity pattern, the inhibition profile, the enzyme thermal stability pattern, isoelectric focusing pattern, gel filtration profile, and HPLC analysis indicated that JH I and JH III were metabolized by the same JHEs, that were physiochemically distinct from general esterase activity (α-NAE activity). General esterase was relatively unimportant in the metabolism of unbound JH in the plasma of last stadium sugar cane borers.

Chemosterilant and insecticidal activity of mixed aflatoxins against Anthonomus grandis (Coleoptera).

Abstract A mixture of the four major aflatoxins at 0.06 ppm in food supplied to adult boll weevils, Anthonomus grandis , was an effective chemosterilant.

Sex Pheromone Components of the Buck Moth Hemileuca maia

The sex attractant pheromone blend of Hemileuca maia (Lepidoptera: Saturniidae) from the vicinity of Baton Rouge, Louisiana, has been identified. The major component of the blend is (E10,Z12)-hexadeca-10,12-dienal (E10,Z12–16:Ald), in combination with the minor components (E10,Z12)-hexadeca-10,12-dien-1-ol (E10,Z12–16:OH), and (E10,Z12)-hexadeca-10,12-dien-1-yl acetate (E10,Z12–16:Ac). Ratios of the compounds in extracts of female pheromone glands varied around a mean of 100:7.4:6.3. None of the three components were attractive to male moths when tested as single components. Several other compounds were tentatively identified from female pheromone gland extracts, including E10,E12–16:Ald, E10,E12–16:OH, and E10,E12–16:Ac, but addition of these components, either alone or in combination, at biologically relevant rates, did not significantly increase the attractiveness of lures. The saturated analogs, hexadecanal, hexadecanol, and hexadecyl acetate, also were identified in gland extracts, but had no apparent effect as pheromone components.

Identification of unique pheromone components for soybean looper mothPseudoplusia includens.

Analysis of sex pheromone glands from individual female soybean looper moths showed that in addition to the previously identified main component (Z)-7-dodecenyl acetate, the compounds dodecyl acetate, 11-dodecenyl acetate, (Z)-7-dodecenyl propionate, and (Z)-7-dodecenyl butanoate were also produced. Two of the components, 12∶OAc and 11–12∶OAc, were not detected in a single analysis of female effluvium. Flight-tunnel tests showed that the five-component and three-component blends were equal to each other and to a female extract (> 80% source contacts) and that the mixtures were superior toZ7–12∶OAc alone. Field tests indicated that the five-component blend was significantly more attractive thanZ7–12∶OAc alone at a dosage of 1 mg, but that the blend was only slightly better at 3 mg.

Photoperiodically induced delayed insect metamorphosis: a larval oligopause inDiatraea saccharalis

Sugarcane borers enter a state of delayed metamorphosis when exposed to a 12-h photophase at 21°C. Larval feeding, growth, and molting continues but pupation is suppressed under these conditions.

Looplure efficacy and electrophysiological responses in three plusiinae species.

Source concentration differences of (Z)-7-dodecen-1-ol acetate, or looplure, were evaluated for field trapping efficiency and electrophysiological responses with malePseudoplusia includens (Walker),Trichoplusia ni (Hubner) andRachiplusia ou (Guenné) (Lepidoptera: Noctuidae). Sticky traps baited with 1000 μg of the lure captured a significantly greater (P < 0.05) number of maleP. includens andT. ni than any other concentration;R. ou males were caught at a greater rate in traps baited with 100 μg of looplure, significantly more (P < 0.05) than with 1000 μg. Electroantennogram (EAG) studies demonstrated that antennae of maleP. includens have a lower response threshold to looplure than eitherT. ni orR. ou antennae, the latter demonstrating the highest significant threshold of response. No differences in the stimulus-response functions of the three species were detected.