Showing papers by "Jocelyn G. Millar published in 2008"
TL;DR: A pheromone blend of this complexity, composed of alkanediols, terpenoids, and aromatic alcohols, is unprecedented for cerambycid species.
Abstract: Bioassays conducted with a Y-tube olfactometer provided evidence that both sexes of the cerambycid beetle Megacyllene caryae (Gahan) were attracted to odor produced by males. Odor collected from male M. caryae contained eight male-specific compounds: a 10:1 blend of (2S,3R)- and (2R,3S)-2,3-hexanediols (representing 3.2 ± 1.3% of the total male-specific compounds), (S)-(−)-limonene (3.1 ± 1.7%), 2-phenylethanol (8.0 ± 2.4%), (−)-α-terpineol (10.0 ± 2.8%), nerol (2.1 ± 1.5%), neral (63.3 ± 7.3%), and geranial (8.8 ± 2.4%). Initial field bioassays determined that none of these compounds was attractive as a single component. Further field trials that used a subtractive bioassay strategy determined that both sexes were attracted to the complete blend of synthetic components, but the elimination of any one component resulted in a decline in trap captures. Blends that were missing (2S,3R)-2,3-hexanediol, (2R,3S)-2,3-hexanediol, or citral (a 1:1 mixture of neral and geranial) attracted no more beetles than did controls. A pheromone blend of this complexity, composed of alkanediols, terpenoids, and aromatic alcohols, is unprecedented for cerambycid species.
70 citations
TL;DR: Odors from fresh chicken feces in water elicited upwind flight of host-seeking female Culex quinquefasciatus mosquitoes in a dual-choice olfactometer, the first reported example of avian fecal odor eliciting upwindFlight of female mosquitoes.
59 citations
TL;DR: In laboratory bioassays, insect-produced and synthetic murganiol attracted harlequin bugs of both sexes, suggesting that murgantiol is a male-produced aggregation pheromone, analogous to those found in a number of other phytophagous bug species.
Abstract: Sexually mature male harlequin bugs produced a sex-specific compound, identified as one of the stereoisomers of the sesquiterpene epoxyalcohol 4-[3-(3,3-dimethyloxiran-2-yl)-1-methylpropyl]-1-methylcyclohex-2-en-1-ol (henceforth murgantiol), a compound with four chiral centers and 16 possible stereoisomers Production of the compound was highest during the middle of the day Individual virgin male bugs in separate containers produced the compound at a higher rate than virgin males in groups The carbon skeleton was verified by synthesis of several mixtures which, in total, contained all possible isomers, one of which matched the insect-produced compound The relative and absolute configurations of the insect-produced compound remain to be determined In laboratory bioassays, insect-produced and synthetic murgantiol attracted harlequin bugs of both sexes, suggesting that murgantiol is a male-produced aggregation pheromone, analogous to those found in a number of other phytophagous bug species
47 citations
TL;DR: Observations of mating behavior and playback experiments showed that the abdominal vibration signals had both long range calling and short range recognition functions, and Tremulatory signals were essential for copulation to occur.
Abstract: Mating behaviors of the predaceous spined soldier bug, Podisus maculiventris (Say) (Pentatomidae: Asopinae), were observed, and vibrational signals used in intraspecific communication were recorded and analyzed. Only males produced vibrational signals, using three different vibrational modes: vibration of the abdomen, percussion with the front legs, or tremulation of the body. When recorded on a nonresonant substrate (a loudspeaker membrane), the mean dominant frequency of signals produced by abdominal vibration varied between 90 and 140 Hz, and of tremulatory signals between 8 and 22 Hz. Percussion signals were broad-band, with the dominant frequency ≈97 Hz and lower amplitude spectral peaks between 1,500 and 3,000 Hz. In the courtship phase of mating behavior, males emitted pulse trains composed of an abdominal vibration after a tremulatory pulse. Females stimulated by signals of abdominal vibration and composite signals expressed searching behavior and orientation toward the source of vibration, whereas no specific reaction to tremulatory signals was observed. Observations of mating behavior and playback experiments showed that the abdominal vibration signals had both long range calling and short range recognition functions. Tremulatory signals were emitted at close range and were essential for copulation to occur. The sequences of fast and repeated percussion signals were emitted both as individual signals during calling and courting or between vibratory and tremulatory pulses. However, unlike the other vibrational signals, percussion did not seem to be emitted in a particular behavioral context, and its possible function in eliciting responses from females is unclear.
39 citations
TL;DR: Big Island Laupala possessed a reduced number of alkenes as well as a reduction in the diversity of methyl-branch positions relative to species sampled from Maui (ancestral), thus supporting the hypothesis of a founder-induced loss of chemical diversity.
Abstract: A previous investigation of cuticular hydrocarbon variation among Hawaiian swordtail crickets (genus Laupala) revealed that these species differ dramatically in composition of cuticular lipids. Cuticular lipid extracts of Laupala species sampled from the Big Island of Hawaii also possess a greatly reduced number of chemicals (as evidenced by number of gas chromatography peaks) relative to ancestral taxa sampled from the geologically older island of Maui. One possible explanation for this biogeographic pattern is that reduction in chemical diversity observed among the Big Island taxa represents the loss of ancestral hydrocarbons found on Maui. To test this hypothesis, we characterized and identified the structures of cuticular hydrocarbons for seven species of Hawaiian Laupala, two from Maui (ancestral) and five from the Big Island of Hawaii (derived) by using gas chromatography-mass spectrometry. Big Island Laupala possessed a reduced number of alkenes as well as a reduction in the diversity of methyl-branch positions relative to species sampled from Maui (ancestral), thus supporting our hypothesis of a founder-induced loss of chemical diversity. The reduction in diversity of ancestral hydrocarbons was more severe within one of the two sister lineages on the Big Island, suggesting that post-colonizing processes, such as drift or selection, also have influenced hydrocarbon evolution in this group.
30 citations
TL;DR: Life history parameters and reproductive behaviors of the harlequin bug, Murgantia histrionica Hahn, were determined and it was suggested that a primary reason for failure to copulate by virgin males was the incorrect rotation of their pygophores to the copulation position, so that successful alignment of the genitalia could not occur.
Abstract: Life history parameters and reproductive behaviors of the harlequin bug, Murgantia histrionica Hahn (Heteroptera: Pentatomidae), were determined. Total developmental time from egg to adult was48 d. After a sexual maturation period of7 d, both sexes mated repeatedly, with females laying multiple egg masses of 12 eggs at intervals of 3 d. Adult females lived an average of 41 d, whereas adult males lived an average of 25 d. Courtship and copulation activities peaked in the middle of the photophase. In mating experiments in which mixed sex pairs of virgin and previously mated bugs were combined in all possible combinations, the durations of courtship and copulation by virgin males were signiÞcantly longer with both virgin and previously mated females than the same behaviors for previously mated males. When given a choice between a virgin or previously mated female, previously mated males preferred to mate with virgin females, whereas virgin males showed no preference for virgin over previously mated females. Analyses of mating behaviors with ethograms and behavioral transition matrices suggested that a primary reason for failure to copulate by virgin males was the incorrect rotation of their pygophores to the copulation position, so that successful alignment of the genitalia could not occur.
25 citations
TL;DR: Several of the Chlorochroa spp.
Abstract: The substrate-borne vibrational songs produced by phytophagous stink bugs of the genus Chlorochroa (Heteroptera: Pentatomidae) were recorded and compared. Sex- and species-specific vibrational songs were recorded from both sexes of three stink bug species of agricultural importance, the congeners Chlorochroa uhleri Stal, Chlorochroa sayi (Stal), and Chlorochroa ligata (Say). The temporal and spectral characteristics of the songs were determined, along with the context in which they were produced relative to contact between signalers and receivers. Vibrational communication started with production of the calling song by C. ligata females (FS-1), and by males of C. uhleri (male song [MS]-1) and C. sayi (MS-1). Males of all three species produced courtship songs (MS-2), whereas only C. ligata and C. sayi produced rivalry songs. Copulatory songs were produced by all three species, but they could not be attributed to either sex. Several of the songs share similarities in their fine-scale time units th...
24 citations
TL;DR: Comparison of theoretical and experimental vibrational circular dichroism (VCD) spectra of an enantiopure synthetic sample of the obscure mealybug sex pheromone allowed the determination of the absolute configuration of the insect's phersomone.
22 citations
TL;DR: The highly unsaturated aldehyde (9Z)-9,13-tetradecadien-11-ynal and corresponding alcohol were identified as possible sex pheromone components of the avocado seed moth, Stenoma catenifer as mentioned in this paper.
17 citations
TL;DR: Findings indicate that there are two pheromone types of the pecan nut casebearer, and they have major implications for the direct use of these phersomones in pecan IPM.
Abstract: The sex pheromone of the monophagous Acrobasis nuxvorella Neunzig (Lepidoptera: Pyralidae) was reported as (9E,11Z)-hexadecadienal (9E,11Z-16:Ald) (Biorg. Med. Chem. 4: 331-339, 1996), and it has since been an effective integrated pest management (IPM) tool for monitoring this pest in the United States, but not in Mexico. Field and laboratory studies were conducted to confirm that the species in Mexico was indeed A. nuxvorella and to investigate the pheromone chemistry of the Mexican populations of this species. Initial field trials testing compounds structurally related to the known pheromone component, and blends thereof, indicated that a 100 microg:100 microg blend of (9E,11Z)-hexadecadien-1-yl acetate (9E,11Z-16:Ac):9E,11Z-16:Ald in rubber septa was effective in attracting male moths in Mexico. Coupled gas chromatography-electroantennogram analyses confirmed the presence of these compounds in extracts of pheromone glands of females, and antennae of male moths also responded to the alcohol analog (9E,11Z)-hexadecadien-1-ol (9E,11Z-16:OH). Subsequent field trials of various blends of these three compounds in Mexico showed that 1) both the acetate and aldehyde components were required for optimal attraction of male moths of the Mexican populations, and 2) addition of the alcohol suppressed attraction of males in a dose-dependent manner. Tests with the 1:1 9E,11Z-16:Ac:9E,11Z-16:Ald blend at various sites in the United States showed that this blend attracted some moths, but that moths attracted to 9E,11Z-16:Ald alone were predominant in the population. Furthermore, in preliminary studies the latter seemed not to respond to the blend. These findings indicate that there are two pheromone types of the pecan nut casebearer, and they have major implications for the direct use of these pheromones in pecan IPM.
15 citations
TL;DR: In this paper, a short and completely stereospecific synthesis of (E )-2-isopropyl-5-methyl-2,4-hexadienyl acetate, the very recently identified sex pheromone of the passionvine mealybug Planococcus minor, is described.
TL;DR: A successful strategy is presented for the collection of a strain of the egg parasitoid Avetianella longoi Siscaro, that parasitizes eggs of the longhorned borer Phoracantha recurva Newman (Coleoptera: Cerambycidae).
Abstract: Selectively collecting a single natural enemy species that parasitizes one member of a guild of herbivores that attack the same host plants can be a challenging problem during development of biological control programs. We present here a successful strategy for the collection of a strain of the egg parasitoid Avetianella longoi Siscaro (Hymenoptera: Encyrtidae), that parasitizes eggs of the longhorned borer Phoracantha recurva Newman (Coleoptera: Cerambycidae). This cerambycid is one member of a large guild of woodborers that simultaneously infest dying and fallen Eucalyptus in Australia, and it has become a major pest of Eucalyptus in many areas of the world where Eucalyptus has been introduced. Adult P. recurva of both sexes were caged on freshly cut Eucalyptus logs, and the resulting egg masses were marked and then left exposed to natural parasitization in the field. Parasitized egg masses were then harvested and held in the laboratory until adult parasitoids emerged. Parasitoids were identified as A. longoi by morphological comparisons with reference specimens, and with molecular markers. This strain of A. longoi readily accepted and had high survival rates in eggs of P. recurva. In contrast, the strain of A. longoi that has been used for biological control of P. semipunctata in California since the 1990s strongly prefers eggs of eucalyptus longhorned borer, Phoracantha semipunctata (F.) (Coleoptera: Cerambycidae), and has relatively low rates of survival to adulthood in eggs of P. recurva. The causes of these behavioral and physiological differences between the two strains are not yet known.
TL;DR: Similarities between the sex pheromone of H. burnsi and that of the allopatric Hemileuca electra electra support a case for reproductive character displacement in the phersomone communication channel ofH.
Abstract: The sex pheromone blend of Hemileuca burnsi (Lepidoptera: Saturniidae) from the western Mojave Desert was determined to be a combination of (10E,12Z)-hexadecadien-1-yl acetate (E10,Z12-16:Ac), (10E,12Z)-hexadecadien-1-ol (E10,Z12-16:OH), (10E,12E)-hexadecadien-1-yl acetate (E10,E12-16:Ac), and hexadecyl acetate (16:Ac). (10E,12Z)-Hexadecadienal (E10,Z12-16:Ald) was tentatively identified in pheromone gland extracts based on electroantennographic responses and, when added to the above blend, it enhanced trap captures at low doses. The mean ratio of the compounds in extracts of pheromone glands was 100:23:232:14:0.4 (E10,Z12-16:Ac: E10,E12-16:Ac: 16:Ac: E10,Z12-16:OH: E10,Z12-16:Ald). Field trials indicated that although E10,Z12-16:Ac and E10,Z12-16:OH were essential for attraction, the two-component blend was not attractive by itself. Addition of the three other compounds was necessary for maximum attraction, rendering this the most complicated pheromone blend described for a Hemileuca species to date. Similarities between the sex pheromone of H. burnsi and that of the allopatric Hemileuca electra electra and differences between the blends of H. burnsi and that of the sympatric H. electra mojavensis support a case for reproductive character displacement in the pheromone communication channel of H. electra.