A Symmetrical Diester as the Sex Attractant Pheromone of the North American Click Beetle Parallelostethus attenuatus (Say) (Coleoptera: Elateridae)

Hexanoic acid, 1-octanol, 1,8-octanediol, octyl hexanoate, 1,8-octanediol monohexanoate, and 1,8-octanediol dihexanoate were identified in headspace volatiles collected from the crushed abdomen of a female click beetle of the species Parallelostethus attenuatus (Say) (Elaterinae, tribe Elaterini). In field trials carried out in Illinois, South Carolina, North Carolina, and Virginia, adult male beetles were strongly attracted to 1,8-octanediol dihexanoate alone. Blends of the dihexanoate with one or more of the other compounds proved to be less attractive than the dihexanoate alone, suggesting that the pheromone of this species may consist of a single compound. The symmetrical diester structure of the pheromone is a novel natural product and appears to be structurally unique among insect pheromones.

     

Defensive Chemistry of an Aposematic Bug, Pachycoris stallii Uhler and Volatile Compounds of Its Host Plant Croton californicus Muell.-Arg.

Volatile components of Pachycoris stallii scent gland secretions and the bug's host plant, Croton californicus, were identified by gas chromatography and mass spectroscopy. The predominant compounds isolated from C. californicus fruit and leaves were -myrcene and -caryophyllene. Metathoracic gland secretions of P. stallii contained mostly (E)-2-hexenal, (E)-4-oxo-2-hexenal, (E)-2-hexenyl acetate, and n-tridecane. In males, n-tridecane was present throughout the metathoracic gland, but in females this compound was found only in the median reservoir/accessory gland. (E)-2-Hexenal was present throughout the gland of female bugs, but in males was primarily present in the median reservoir/accessory gland. (E)-4-Oxo-2-hexenal and n-dodecane were isolated from the median reservoir/accessory gland of male and female bugs. Metathoracic glands were sexually monomorphic. Data from chemical analyses and anatomical observations suggest that dorsal abdominal glands of adults were apparently obsolescent. In nymphs, dorsal abdominal glands produced (E)-2-hexenal, (E)-4-oxo-2-hexenal, n-dodecane, n-tridecane, and tetradecanal. The proportion of the predominant constituent, (E)-4-oxo-2-hexenal, decreased from 72% in the first instar to 47% in the fourth instar. Proportions of tetradecanal and n-tridecane were greater in the fourth instar than in the first instar. Observations of dissected glands indicated that median and posterior dorsal abdominal glands of all nymphal instars were more developed than anterior dorsal abdominal glands. Scanning electron micrography revealed the presence of polygonal microsculpturing on the integument surrounding the ostioles of metathoracic and dorsal abdominal glands. Chemical, anatomical, and behavioral data indicated that P. stallii has a chemical defense system based on short-chain carbonyl compounds and that this system is directed against arthropods. The abundance of arthropod natural enemies apparently has forced P. stallii to maintain this defense system despite feeding on a toxic host plant.     

Deverbal Semantics and the Montagovian Generative Lexicon \Lambda \!\mathsf {Ty}_n

We propose a lexical account of event nouns, in particular of deverbal nominalisations, whose meaning is related to the event expressed by their base verb. The literature on nominalisations often assumes that the semantics of the base verb completely defines the structure of action nominals. We argue that the information in the base verb is not sufficient to completely determine the semantics of action nominals. We exhibit some data from different languages, especially from Romance language, which show that nominalisations focus on some aspects of the verb semantics. The selected aspects, however, seem to be idiosyncratic and do not automatically result from the internal structure of the verb nor from its interaction with the morphological suffix. We therefore propose a partially lexicalist approach view of deverbal nouns. It is made precise and computable by using the Montagovian generative lexicon, a type theoretical framework introduced by Bassac, Mery and Retoré in this journal in 2010. This extension of Montague semantics with a richer type system easily incorporates lexical phenomena like the semantics of action nominals in particular deverbals, including their polysemy and (in)felicitous copredications.     

Plant Volatiles Influence Electrophysiological and Behavioral Responses of <Emphasis Type="Italic">Lygus hesperus</Emphasis>

Previous laboratory studies have shown that the mirid Lygus hesperus is attracted to volatiles emitted from alfalfa; feeding damage increases the amounts of several of these volatiles, and visual cues can enhance attraction further. The present study tested single plant volatiles in electrophysiological and behavioral trials with L. hesperus. Electroantennogram (EAG) analyses indicated that antennae responded to most plant volatiles included in the test, and that when gender differences were observed, males usually were more responsive than females. Antennal responses to the alcohols ((E)-3-hexenol, (Z)-3-hexenol, 1-hexanol), the acetate (E)-2-hexenyl acetate, and the aldehyde (E)-2-hexenal were among the strongest. Moderate responses were observed for (E)-β-ocimene, (E,E)-α-farnesene, (±)-linalool, and methyl salicylate. A dose dependent response was not observed for several terpenes (β-myrcene, β-caryophyllene, (+)-limonene, or both (R)-(+)- and (S)-(−)-α-pinenes). EAG responses, however, were not always consistent with behavioral assays. In Y-tube bioassays, males did not exhibit a positive behavioral response to any of the compounds tested. Instead, males were repelled by (E)-2-hexenyl acetate, (±)-linalool, (E,E)-α-farnesene, and methyl salicylate. In contrast, female L. hesperus moved upwind towards (R)-(+)-α-pinene, (E)-β-ocimene, and (E,E)-α-farnesene, and showed a negative response towards (Z)-3-hexen-1-ol, (S)-(−)-α-pinene, and methyl salicylate. This study emphasizes the use of multiple approaches to better understand host plant finding in the generalist herbivore L. hesperus.     

Increased axon number in the anterior commissure of mice lacking a corpus callosum

Relatively few behavioral deficits are apparent in subjects with hereditary absence of the corpus callosum (CC). The anterior commissure (AC) has been suggested to provide an extracallosal route for the transfer of interhemispheric information in subjects with this congenital defect. Anterior commissure size, axon number, axon diameter, and neuronal distribution were compared between normal mice and those with complete CC absence. No difference in midsagittal AC area was found between normals and acallosals, nor were differences found in the numbers or diameters of myelinated axons. However, axon counts indicated an 17% increase or about 70,000 more unmyelinated axons in the AC of acallosal mice, and the mean diameter of unmyelinated axons was slightly less than in normal mice (0.24 vs 0.26 microm). This decrease in axon diameter enabled more axons to pass through the AC without increasing its midsagittal area. The topographical distribution of neurons sending axons through the AC, assessed with lipophilic dyes, was qualitatively similar for almost all the known regions of origin of the anterior commissure in normal and acallosal mice. There was a pronounced deficit of AC cells in the anterior piriform cortex of BALB/c mice, but this occurred whether or not the mouse suffered absent CC. Although the increase in AC axon number is far smaller than the number of CC axons that fail to reach the opposite hemisphere, the higher number of axons present in the AC of acallosal mice may contribute to the functional compensation for the loss of the CC.     

EAG-Active Herbivore-Induced Plant Volatiles Modify Behavioral Responses and Host Attack by An Egg Parasitoid

Volatiles emitted by plants in response to feeding by Lygus species were tested in neurophysiological, behavioral, and parasitism trials with Anaphes iole, an egg parasitoid of Lygus. Electroantennogram analyses indicated that A. iole antennae responded to most herbivore-induced plant volatiles (HIPVs) tested and that females were usually more responsive than males. Antennal responses to (Z)-3-hexenyl acetate and methyl salicylate were among the strongest. Behavioral assays in a four-arm olfactometer demonstrated that response of female wasps to (Z)-3-hexenyl acetate varied greatly depending on preconditioning regime. Preconditioning wasps to complex host-plant odors led to stronger preference than did a single preconditioning stimulus, i.e., (Z)-3-hexenyl acetate. In a horizontal wind tunnel, female wasps were attracted by methyl salicylate and alpha-farnesene. Parasitism of Lygus lineolaris eggs by A. iole in a cotton field was greater when the eggs were associated with (Z)-3-hexenyl acetate or alpha-farnesene than with controls. Overall, the results of this study show that A. iole can perceive a variety of plant volatiles released after its host damages plants, that the degree of associative learning in A. iole can be manipulated based on preconditioning regime, and that single synthetic HIPVs are attractive to A. iole and can be used to increase attack rates on host eggs. Therefore, it appears that HIPVs have potential for use in suppression of Lygus population densities.     

Allelochemicals produced during glucosinolate degradation in soil

A variety of plant pests are suppressed by the incorporation of cruciferous plant material into soil. Although this effect is attributed to decomposition of glucosinolates into toxic products, little is known concerning glucosinolate degradation in the soil environment. Arenas (30 × 18 × 8 cm) that contained soil amended with 30 g defatted winter rapeseed meal (Brassica napus L.)/kg soil on one half and unamended soil on the other were constructed. Isothiocyanate concentrations in the soil were measured using infrared analysis of CC1₄ extracts, and ionic thiocyanate (SCN^–) using ion chromatography on aqueous extracts. Quantities were monitored during a 100-hr time period in conjunction with a wireworm bioassay. Isothiocyanate production reached a maximum of 301 nmol/g soil at 2 hr, but decreased by 90% within 24 hr. Production of SCN^– reached a maximum of 180 nmol/g soil at 8 hr but persisted longer than isothiocyanate. Separate late instar wire-worms (Limonius infuscatus Mots.) were repelled by the presence of rapeseed meal in less than 24 hr even though the meal was shown in separate experiments not to be toxic. We propose that rapidly produced isothiocyanates are responsible for this repellency, but other products such as SCN^– may play a role.     

A facile noncatalytic methyl ester production from waste chicken tallow using single step subcritical methanol: Optimization study

In this modern era, an increase in urbanization causes the escalating trend of fuel demand as well as environmental pollution problems. Various biofuels research with the respect of climate change and emission reduction recently intensifies, particularly in biodiesel. In Indonesia, diesel oil currently in use contains 20% of biodiesel. Utilizing waste‐based resources such as rendered chicken tallow as the feedstock could be the solution to both energy and environmental challenges. However, chicken tallow contains a significant amount of free fatty acid (FFA) which will obstruct the production yield of biodiesel. In this study, catalyst‐free subcritical methanol has been employed to convert waste chicken tallow (WCT) with high FFA into biodiesel. Design of experiment was conducted to study the effect of temperature, time, and the molar ratio of methanol to fats on the purity and recovery of fatty acid methyl esters (FAMEs). Based on the optimization study performed by response surface methodology (RSM), all three independent variables gave a significant effect on the recovery of FAME. From the experimental results, the maximum FAME yield obtained was 98.43 ± 0.22% with the optimum condition as follows: 167°C, 36.8 minutes, and 42.7:1 (methanol/WCT, mol/mol), while the predicted FAME yield obtained using RSM was 97.76%. The methyl ester composition of WCT‐based biodiesel ranges from C13 to C24.     

Lygus hesperus feeding and salivary gland extracts induce volatile emissions in plants

Induction of plant volatiles by leaf-chewing caterpillars is well documented. However, there is much less information about volatile induction by insects with different feeding habits. We studied the induction of plant volatiles by a piercing–sucking insect, the western tarnished plant bug Lygus hesperus Knight. Adults of both genders and nymphs of Lygus induced the local emission of a blend of volatiles from both cotton and maize. Feeding by Lygus also induced the systemic emission of volatiles that was similar but less complex than the blend emitted at the site of feeding. Infestation by mated, mature adult females (>4 days old), but not by nymphs or mature males, caused detectable emission of -pinene, myrcene, and (E)--caryophyllene, compounds that are stored in the glands of cotton tissue. This indicated that damage to glands in the petiole and leaf by the female ovipositor, rather than feeding, contributed significantly to the emission of these volatiles. Girdling the plant stem to disrupt phloem transport markedly decreased the movement of ¹⁴C-labeled photosynthetic products to the apex of the plant, and this treatment also markedly reduced the amount of systemically induced volatiles caused by Lygus feeding. Lygus salivary gland extracts were capable of inducing emission of the same volatile blend as measured for plants infested by feeding insects or treated with volicitin, an elicitor isolated from caterpillar regurgitant. The results indicate that L. hesperus is capable of inducing the emission of plant volatiles and that induction is caused by an elicitor that is contained in the insect salivary gland.     

Different food sources affect the gustatory response of Anaphes iole,an egg parasitoid of Lygus Spp

The gustatory response of female Anaphes iole wasps to naturally occurring carbohydrates, a commercial food source, and host (Lygus lineolaris) frass was determined. Wasps responded to all 14 of the sugars at the highest concentration tested (2 M). At this concentration, sucrose, glucose, maltose, melezitose, fructose, and erlose all elicited <90% acceptance. The lowest concentration that evoked a response (=acceptance threshold) for these sugars was >1/256 M, with the exception of glucose, which was 1/16 M. Raffinose, trehalose, mannose, galactose, melibiose, rhamnose, stachyose, and lactose led to >50% gustatory response by the wasps at 2 M, and were categorized as moderately stimulatory sugars. The acceptance threshold for these sugars was <1/4 M, with the exception of raffinose, which was 1/256 M. In trials with moderately stimulatory sugars combined with either sucrose or maltose, only the rhamnose+maltose mixture significantly inhibited the gustatory response of A. iole. Food and water deprived parasitoids readily accepted the moderately stimulatory sugars. Eliminade^TM, a commercial food supplement, was readily accepted (92%) by A. iole. Conversely, the wasps did not feed on host frass. Chemical analysis of L. lineolaris frass demonstrated the presence of glucose, sucrose, fructose, trehalulose, and melezitose, apparently at concentrations below those perceived by A. iole. The latter two compounds were previously known only from homopteran honeydew (trehalulose and melezitose) and bacteria (trehalulose). With respect to gustatory response to nectar and honeydew sugars, A. iole differs markedly from other hymenopterans that have been studied in that this parasitoid accepted all the naturally occurring sugars with which it was tested. Moreover, this parasitoid had lower acceptance thresholds than other hymenopterans for many of the sugars. This broad and sensitive range of gustatory perception might be helpful in the development of a food source for the wasp that is not exploited by the host.