Identification of the Tandem Running Pheromone in Diacamma sp. from Japan (Hymenoptera, Formicidae)

The Japanese queenless ponerine ant Diacamma sp. from Japan employs tandem running during nest relocation, in which a leader ant guides nestmate followers one at a time. We replicated this process by presenting one entire abdominal part of a leader, except for the petiole to followers. When the abdominal part had been rinsed with n-hexane, however, it attracted significantlyfewer followers. This suggests that chemicals on the leader’s abdominal part evoke tandem running. Dissection of abdominal major exocrine glands revealed that the Dufour’s gland was the source of this chemical signal. The chemicals were eluted in the hydrocarbon fraction by silica-gel column chromatography, and the quantitatively major component was estimated as heptadecene (C17:1) through gas chromatograph-mass spectrometer (GCMS) analysis. The position of the double bond was estimated to be between the 8th and 9th carbons through analysis of the epoxidized compound. Only (Z)-isomers of 8-heptadecene evoked tandem running in the followers. We identified the tandem running pheromone of this ant species to be (Z)-8- heptadecene. (163

Cuticular Hydrocarbon Content that Affects Male Mate Preference of Drosophila melanogaster from West Africa

Intraspecific variation in mating signals and preferences can be a potential source of incipient speciation. Variable crossability between Drosophila melanogaster and D. simulans among different strains suggested the abundance of such variations. A particular focus on one combination of D. melanogaster strains, TW1(G23) and Mel6(G59), that showed different crossabilities to D. simulans, revealed that the mating between females from the former and males from the latter occurs at low frequency. The cuticular hydrocarbon transfer experiment indicated that cuticular hydrocarbons of TW1 females have an inhibitory effect on courtship by Mel6 males. A candidate component, a C25 diene, was inferred from the gas chromatography analyses. The intensity of male refusal of TW1 females was variable among different strains of D. melanogaster, which suggested the presence of variation in sensitivity to different chemicals on the cuticle. Such variation could be a potential factor for the establishment of premating isolation under some conditions

GNSS Array Antenna for Mitigating Multipath Errors in Urban Environment

GNSS signal vulnerability has been a major concern especially for safety-of-life applications such as aircraft operations. Therefore, a GNSS array antenna technology was investigated focusing on beamforming to mitigate multipath errors in urban environment including airport surfaces. A commercial three-element GNSS antenna and RF-Front end were used to obtain digital IF data. The recorded In-phase/Quadrature IF data for three antennas were combined with proper weight to form beams towards satellites after so-called hardware biases were calibrated. Test results in multipath-rich environment demonstrated that 50-70% reduction of pseudorange errors due to multipath were possible if the beamforming algorithms were applied

Field-Induced Effects of Anisotropic Magnetic Interactions in SrCu2(BO3)2

We observed a field-induced staggered magnetization in the 2D frustrated dimer-singlet spin system SrCu2(BO3)2 by 11B NMR, from which the magnitudes of the intradimer Dzyaloshinsky-Moriya interaction and the staggered g-tensor were determined. These anisotropic interactions cause singlet-triplet mixing and eliminate a quantum phase transition at the expected critical field Hc for gap closing. They also provide a quantitative account for some puzzling phenomena such as the onset of a uniform magnetization below the and the persistence of the excitation gap above Hc. The gap was accurately determined from the activation energy of the nuclear relaxation rate.Comment: 8 pages, 5 figures, published versio

Nutritional analysis, volatile composition, antimicrobial and antioxidant properties of Australian green ants (Oecophylla smaragdina)

Edible green ants (Oecophylla smaragdina) are distributed in Asia, Australia, and the Pacific Islands, and are known for their pharmacological and nutritional applications, yet various properties are to be explored. Nutritional value, volatile compounds, antimicrobial and antioxidant potential were determined in four body regions [ant nest, whole ant, anterior part of the body, and gaster]. Proximate analysis revealed the anterior part have higher protein and fibre content, whilst fat content was higher in the gaster. GC–MS analysis revealed the complexity of ant nest with most compounds being organic acids, alcohols and alkanes. Antimicrobial activity was observed for whole ants (ZOI: 13.3 ± 0.8 mm) and anterior part (ZOI: 11.9 ± 0.5 mm) methanol extracted against Staphylococcus aureus (~104 CFU/ml). Whole ants methanol (813 ± 22.6 µg TROLOX eq/g of DW) and water (617.6 ± 59.2 µg TROLOX eq/g of DW) extracted exhibited higher free radical scavenging capacity amongst the four ant body regions. Whole ants water extracted (7 ± 0.4 mg GAE/g of DW) had the highest total phenolic content. In the methanol extracts, the gaster (6.2 ± 0.2 mg GAE/g of DW) exhibited the highest phenolic content. Whole ants exhibit good antioxidant and antimicrobial activity and considerable folate content

Olfactory detection of prey by the termite-raiding ant Pachycondyla analis

The African termite-raiding ant Pachycondyla analis Latreille (Hymenoptera: Formicidae) organizes group raids on termites of the sub-family Macrotermitinae. Termites and ants occupy and share similar habitats, resulting in a co-evolutionary arms race between termites as prey and ants as predators. The present study explored whether P. analis uses semiochemical signaling cues to detect potential termite prey prior to and during raids. Ants’ responses to odors emitted from termites alone, termite gallery soil, and termites inside their galleries were tested using Y-tube olfactometer assays. The results showed that P. analis detected odors of termites and those of their galleries, and odors from termites inside their galleries were more attractive to both minor and major ant workers than odors from termites alone. The composition of these odor sources was identified using gas chromatography- mass spectrometry analysis. While the odors from termite gallery soils were compositionally richer (containing 13 compounds rather than nine from termites alone), those from the termites alone were quantitatively richer, releasing about six times more odors than gallery soil. Most of the compounds in the odor profiles were identified as hydrocarbons. Naphthalene, previously identified as an insect repellent, was also identified as a component of the odors from the gallery soil. These results demonstrate that odors play an important role in prey detection by P. analis.This research was funded in part by the Dutch SII through project 2004/09 Activity No. 10799 to icipe, The National Research Foundation (NRF), and a DAAD fellowship to AAY.http://www.insectscience.orgam201

Differences in Male Mate Recognition between the Invasive <i>Anoplophora glabripennis</i> (Coleoptera: Cerambycidae) and Japanese Native <i>A. malasiaca</i>

The Asian longicorn beetle Anoplophora glabripennis is a recently arrived invasive species to Japan. The Japanese native A. malasiaca shows an extensive overlap with A. glabripennis with host plants, niches, and emergence season. Hybridization between these two species is suspected in Japan. The surface of the female is covered with contact sex pheromones that elicit male mating behavior within species. We evaluated the contact pheromonal activity of crude extract and fractions of female A. glabripennis coated on a black glass model and revealed a hydrocarbon fraction and a blend of fractions to show activity but relatively weak, suggesting the presence of other unknown active compounds. Few male A. glabripennis showed mating behavior when they were exposed to a crude extract of female A. malasiaca. However, a considerable number of A. malasiaca males mounted and showed abdominal bending behavior when presented with glass models that were coated with each extract of female A. glabripennis and A. malasiaca. Gomadalactones are essential contact pheromone components that elicit mating behavior in male A. malasiaca; however, we could not detect them in female A. glabripennis extract. Here, we investigated the possible reasons for this phenomenon and the difference in male mate recognition systems between these two species

Musty odor of entomopathogens enhances disease-prevention behaviors in the termite Coptotermes formosanus.

Termites often eliminate pathogens directly through mutual grooming, and are thereby prevent infections from entomopathogenic fungi. Our previous study confirmed that the antennae of Coptotermesformosanus sensitively responded to the musty odor of entomopathogenic fungi. However, it is unclear if this odor has any effect on termite behavior. The purpose of this study was to clarify the effects of fungal odor on termite behavior, especially on conidia removal. The musty odor was prepared as an aqueous solution by immersing conidia in distilled water. When untreated termites were mixed with fungal-odor-treated termites at a ratio of 4:1, mutual grooming and attack of treated termites were frequently observed. This indicated that the fungal odor triggered these behavioral responses. While some components of the fungal odor were found in all of the entomopathogenic fungi tested, the odor profiles differed among the isolates

Behavioral changes in the termite, Coptotermes formosanus (Isoptera), inoculated with six fungal isolates.

The studies of pathogen-prevention behaviors of termites have focused on hygiene behavior directed only against highly virulent pathogens. Therefore, we compared behavioral changes in the subterranean termite Coptotermes formosanus following contact with entomopathogenic fungi with different levels of virulence. The fungal virulence was inferred from the daily mortality and the LD(50) value in previous data. When untreated termites were allowed to contact their fungus-inoculated nestmates, mutual grooming was frequent during 30min after inoculation. The inoculated termites were often attacked and eaten by their uninoculated nestmates, and then buried after death. Notably, there was no influence of fungal virulence on these pathogen-prevention behaviors. However, the fungal isolates and genera affected not only the frequency of the behaviors but also the horizontal transmission pattern, the number of dead individuals and the survival period before the first death following infection