Male white grub beetles prefer the pheromone composition of young females in the field.

Females of the white grub beetle, Dasylepida ishigakiensis, release both (R)- and (S)-2-butanol as sex pheromones, but the males are only attracted to (R)-2-butanol. In laboratory-reared females, the proportion of the (R)-isomer decreased significantly as their calling opportunities increased and as they aged. We examined whether such qualitative changes also occur in field populations. We collected virgin females from the field and then trapped and analysed the volatiles emitted during their first and second callings. The ratio of (R)- to (S)-2-butanol (R/S) was 78:22 at the first calling, but shifted to 39:61 at the second calling. While investigating the composition of the female pheromones, the question arose as to whether the male preferences change in response to the shift in female pheromone composition. To answer this question, we observed the behaviour of young and old males in response to various R/S ratios as lures in the laboratory and in the field. In the flight tunnel assay of laboratory-reared individuals, young males touched female models with a 9:1 R/S ratio lure less than those with pure (R)-2-butanol; however, older males touched the two groups with equivalent frequency. In the field trap test, older males were much more attracted to (R)-2-butanol-scented lures. When we tested using lures with the same amount of (R)-2-butanol but added different amounts of the (S)-isomer, we found that increased levels of (S)-2-butanol resulted in lower attractiveness to males. (S)-2-butanol was confirmed to have an inhibitive activity in the attractiveness of (R)-2-butanol.

Age-dependent changes in the ratio of (R)- and (S)-2-butanol released by virgin females of Dasylepida ishigakiensis (Coleoptera: Scarabaeidae).

The females of the white grub beetle, Dasylepida ishigakiensis, release two enantiomers of 2-butanol, (R)-2-butanol and (S)-2-butanol. The ratio describing the relative proportions of these two enantiomers (R/S ratio) has not yet been investigated. (R)-2-Butanol has been shown to attract males in laboratory and field experiments, whereas (S)-2-butanol tends to inhibit them. To determine the R/S ratio of the 2-butanol emitted by virgin females, we collected 2-butanol from young (53 days old), mature (63 days old) and old females (73 days old) using water, extracted with an SPME fibre and subsequently injected into GC-MS. The major component of the 2-butanol emitted by the young females was (R)-2-butanol, but as the females aged, the component ratio favoured (S)-2-butanol. Young females released an 80:20 mixture of (R)- and (S)-2-butanol, whereas old females released a 45:55 mixture. The EAG response of male antennae to a 50:50 ratio (racemic mixture) showed a similar dose-response curve to that of (R)-2-butanol. The male orientation responses to (R)-2-butanol decreased when the relative proportion of (S)-2-butanol increased. An inhibitory and/or masking effect of (S)-2-butanol on male orientation behaviour was also observed in the flight tunnel assay. These results suggest that males are more strongly attracted to young females than to old females. We also discuss the possibility of using 2-butanol isomers as a control or monitoring agent for this insect.

Mating disruption by a synthetic sex pheromone in the white grub beetle Dasylepida ishigakiensis (Coleoptera: Scarabaeidae) in the laboratory and sugarcane fields.

A serious sugarcane pest, Dasylepida ishigakiensis, remains in the soil during most of its life cycle except for a short period for mating. Mating disruption by an artificial release of the sex pheromone (R)-2-butanol (R2B), therefore, may be a feasible method to control this pest. We examined the effects of artificial release of R2B and its related compounds, (S)-2-butanol (S2B) and the racemic 2-butanol (rac-2B), on the mating success of this beetle both in the laboratory and in the field. In flight tunnel experiments, almost all males orientated towards a R2B-releasing source and 40% of them landed on the source. When the atmosphere was permeated with R2B, the frequency of males landing on the model was significantly reduced. Both rac-2B and S2B were less effective, but substantial reduction in landing success by males was achieved at higher rac-2B concentrations. R2B released from polyethylene dispensers in sugarcane plots greatly reduced not only the proportion of females mated with males but also the number of males caught by R2B-baited traps, indicating that male mate-searching behaviour was strongly affected by the released R2B. Similar inhibitory effects on male behaviour were also observed when tube- or rope-type dispensers released high rac-2B concentrations in the field. These results indicate that it would be highly possible to control D. ishigakiensis through the disruption of the sexual communication by releasing either synthetic R2B or rac-2B.

Parasitism, development and adult longevity of the egg parasitoid Telenomus nawai (Hymenoptera: Scelionidae) on the eggs of Spodoptera litura (Lepidoptera: Noctuidae).

When Telenomus nawai Ashmead or Trichogramma ostriniae Pang & Chen (Hymenoptera: Trichogrammatidae) was inoculated into intact egg masses of Spodoptera litura (Fabricius) that were covered with a scale-hair layer, T. nawai emerged from 76% of the eggs, while emergence of T. ostriniae was from only 3% of the eggs. When the hair layer was removed before inoculation, the rate by the latter increased to 21%. These observations confirmed that the hair layer effectively protects S. litura egg masses from attack by T. ostriniae, and that T. nawai parasitism is more effective. In order to assess the feasibility of T. nawai as a biological control agent for S. litura, parasitism rate, development time and adult longevity were examined in the laboratory. Emergence of T. nawai was observed in more than 95% of 0- and 1-day-old separated eggs of S. litura, but the rate decreased to 60% and 0% for 2- and 3-day-old eggs, respectively. The emergence rates of T. nawai were near 95% for temperatures in a range from 25 degrees C to 35 degrees C, but decreased to 80% at 20 degrees C. No parasitoids emerged at 15 degrees C. The developmental periods decreased as temperature increased from 20 degrees C to 35 degrees C. The developmental threshold occurred at 13.7 degrees C and 13.9 degrees C, and the effective accumulative temperatures from egg to adult emergence were 149.3 and 147.1 degree-days for females and males, respectively. Mean longevity of the adult females decreased with increasing temperature; 87.0 days at 15 degrees C and 9.5 days at 35 degrees C. The feasibility of the use of T. nawai for controlling S. litura is discussed.

Parasitoid secretions provoke ant warfare.

Insect social parasites are extreme specialists that typically use mimicry or stealth to enter ant colonies to exploit the rich, but fiercely protected, resources within their nests. Here we show how a parasitic wasp (parasitoid) contrives to reach its host, itself an endangered species of social parasite that lives inside the brood chambers of ant nests, by releasing semiochemicals to induce in-fighting between worker ants, locking the colony in combat and leaving it underprotected. Four of these chemicals are new to biology and have the potential to control pest species by inducing different agonistic behaviours in ants.

Synthesis and characterization of diepoxyalkenes derived from (3Z,6Z,9Z)-trienes: lymantriid sex pheromones and their candidates.

All stereoisomers of three diepoxyalkenes derived from (3Z,6Z,9Z)-trienes with a C21, C19, or C18 straight chain, lymantriid sex pheromones and their candidates, were synthesized by MCPBA oxidation of optically active epoxyalkadienes. Their chromatographic behaviors were examined with GC and LC equipped with achiral and chiral columns. Detailed inspection of the mass spectra of these epoxides indicated the following diagnostic ions for determining the chemical structures: m/z 128, 167, M-87 and M-85 for (Z)-cis-3,4-cis-6,7-diepoxy-9-enes; m/z 111, M-125 and M-69 for (Z)-cis-6,7-cis-9,10-diepoxy-3-enes; and m/z M-125 and M-139 for (Z)-cis-3,4-cis-9,10-diepoxy-6-enes. Mass chromatographic analysis that monitored these fragment ions revealed the existence of a new pheromonal compound with a C21 chain in an extract from virgin females of a lymantriid species, Perina nuda F. The three diepoxyalkenes were converted into the corresponding DMDS adducts, which showed characteristic ions from fragmentation between the two thiomethyl groups, reflecting the position of an original double bond.

Phoretic egg parasitoid,Telenomus euproctidis (Hymenoptera: Scelionidae), uses sex pheromone of tussock mothEuproctis taiwana (Lepidoptera: Lymantriidae) as a kairomone.

The phoretic egg parasitoid,Telenomus euproctidis Wilcox (Hymenoptera: Scelionidae) was found more frequently on virgin than on mated female moths ofEuproctis taiwana (Shiraki) (Lepidoptera: Lymantriidae), when virgin and mated moths were exposed concurrently in the field for 24 hr. A synthetic component of the moth's sex pheromone. (Z)-16-methyl-9-heptadecenyl isobutyrate, attracted both the wasp,T. euproctidis, and maleE. taiwana. These findings suggest thatT. euproctidis uses the sex pheromone of the female moth,E. taiwana, as a kairomone to locate a host female moth and through her the host eggs.

Reproductive biology of the yellow-spotted longicorn beetle,Psacothea hilaris (pascoe) (Coleoptera: Cerambycidae). III. Identification of contact sex pheromone on female body surface.

A major component of female contact sex pheromone of the yellow-spotted longicorn beetle,Psacothea hilaris (Pascoe), was isolated from the elytra and identified as (Z)-21-methyl-8-pentatriacontene. The synthetic compound released the typical mating behavior including holding, mounting, and abdominal bending in males, although its activity was considerably lower than the extract of female elytra when treated on a gelatin capsule as an artificial female model.

Identification of sex attractant pheromone components of the tussock moth,Euproctis taiwana (Shiraki) (Lepidoptera: Lymantriidae).

Two compounds were isolated and identified from abdominal tips of the female tussock moth,Euproctis taiwana (Shiraki), by a combination of gas chromatography-electroantennographic detection, coupled gas chromatography-mass spectrometric analysis, microreaction, and synthesis. These compounds were (Z)-16-methyl-9-heptadecenyl isobutyrate (74.8%) and 16-methylheptadecyl isobutyrate (25.2%). Their total amount was determined to be ca. 29.8 ng/female. Field bioassays showed that (Z)-16-methyl-9-heptadecenyl isobutyrate is a sex attractant for the male moths. These chemical compounds had not previously been found as the sex pheromone components in the genusEuproctis.

Absolute configuration of sex pheromone for tea tussock moth,Euproctis pseudoconspersa (strand)via synthesis of (R)- and (S)-10, 14-dimethyl-1-pentadecyl isobutyrates.

(R)- and (S)-10,14-dimethyl-1-pentadecyl isobutyrates were synthesized from (S)- and (R)-citronellols, respectively. TheR enantiomer was as active as the natural pheromone but theS enantiomer was less active in the electrophysiological analyses, which provided conclusive proof that the absolute configuration of the natural pheromone isR.

A self-controllable mask with helmet to prevent self finger-mutilation in the Lesch-Nyhan syndrome.

Self-mutilation is a characteristic symptom of Lesch-Nyhan syndrome. We report a newly developed orthosis for managing self-mutilation of the fingers through biting. The orthosis has a plastic mask attached to a helmet; the patient can manage the mask with one hand to stop biting fingers on the other hand. This is a report of a 6-year-old boy who was able to control finger biting by using the orthosis. Eighteen months later he has stopped biting his fingers and no longer wears the orthosis.