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Managing pests with insecticides is probably the most conventional available control method. However, insecticide overuse often results in resistance and subsequent pest resurgence, and often adversely affects the ecosystem. The physical management of insect pests by utilizing substrate-borne vibrations, sounds, or both is increasingly attracting attention as an alternative, as it has modest ecosystem impacts. This method exploits vibroacoustic insect communication used for mating and the perception of approaching enemies, provoking behavioral responses in an ingenious manner. We aimed to examine whether substrate-borne vibrations effectively drive away tobacco whiteflies [Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae)], which are serious agricultural pests. To do so, B. tabaci individuals were artificially introduced into greenhouses where tomato (Solanum lycopersicum L.) plants were reared. A substantial reduction in the average density of B. tabaci nymphs and adults was achieved by transmitting vibrational stimuli to the plants. At the same time, no obvious reduction was found in the number of tomato plant flowers. Although the performance of the vibrational device and transmission procedures requires further improvement, the present results shed light on the potential of substrate-borne vibrations as a promising alternative for pest management. [ABSTRACT FROM AUTHOR]

Many groups of insects utilize substrate-borne vibrations for communication. They display various behaviors in response to vibrations in sexual and social communication and in predator-prey interactions. Although the number of reports on communication and behaviors using vibrations has continued to increase across various insect orders, there are several studies of the exploitation of vibrations for pest management in Hemiptera and Coleoptera. Here, we review the studies of behaviors and communication using vibrations in hemipteran and coleopteran insects. For instance, pentatomid bugs display species- and sex-specific vibrational signals during courtship, whereas cerambycid beetles show startle responses to vibrations in the context of predator-prey interactions. Concepts and case studies in pest management using vibrations—especially regarding the disruption of communication and behavior—are also presented. [ABSTRACT FROM AUTHOR]

Sandy beach ecosystems are decreasing worldwide and organisms living there are becoming threatened. The burrowing wolf spider Lycosa ishikariana is one such example. To establish effective conservation strategies under habitat fragmentation, we examined population genetic structure of L. ishikariana from mitochondrial cytochrome oxidase I gene and 6 microsatellite loci. Mitochondrial sequence data revealed 6 population subgroups with very high fixation indices, indicating that L. ishikariana has a clear phylogeographic structure and that the level of differentiation among regions is considerable. In particular, one subgroup in the western Honshu mainland (clade G) has a highly distinct genetic structure, despite having no clear geographic barriers from its parapatric population. Moreover, the distribution ranges of the other two subgroups (clades D and E) were highly restricted, suggesting their vulnerability to local human impacts and highlighting their high conservation priorities. Microsatellite data revealed 10 subgroups that were compatible with the clades identified from the mitochondrial data. Fixation indices among these groups were very high, indicating a limited gene flow induced by male spiders. Based on these results, we proposed six conservation units of L. ishikariana and effective conservation/restoration strategies in the face of ongoing coastal armoring. [ABSTRACT FROM AUTHOR]

Euscepes postfasciatus (Fairmaire) is an invasive pest of the sweet potato ( Ipomoea batatas) and is also parasitic to other wild host plants of the Ipomoea genus. The population density of E. postfasciatus is sometimes greater in Ipomoea pes- caprae L. than in Ipomoea indica (Burm. f.). We investigated the desirability of I. pes- caprae as a host plant for E. postfasciatus in terms of reproductive and developmental potential. Females laid fewer eggs on I. pes- caprae, and the eclosion of their larvae was delayed compared with on I. indica. Furthermore, the larval growth rate was slower on I. pes- caprae than on I. indica. These results suggest that I. pes- caprae is not always the preferred host for egg laying and growth rate in the early developmental stages. However, the larval survival rate after the initial period of development was markedly better on I. pes- caprae than on I. indica. The present simulation study demonstrated that the population density of E. postfasciatus on I. pes- caprae overwhelmed that on I. indica over generations. Comparing the two wild host plant species, I. pes- caprae outweighs I. indica with respect to total population growth, but reproduction on I. indica may be advantageous for the colonization of the new habitat. [ABSTRACT FROM AUTHOR]

The sex pheromone of Herpetogramma submarginale (Swinhoe) was studied by gas chromatography (GC) with electroantennographic detection and GC coupled with mass spectrometry. Two pheromone candidates detected in the gland extracts of females were identified as ( Z)-13-hexadecenyl acetate (Z13-16:OAc) and ( E)-13-hexadecenyl acetate (E13-16:OAc) in a ratio of 87:13 by mass spectral analysis of the natural pheromone components and their dimethyldisulfide adducts. In field tests, Z13-16:OAc alone attracted H. submarginale males and caught significantly more males than live virgin females. Addition of E13-16:OAc did not enhance the attractiveness of Z13-16:OAc. Derivatives of Z13-16:OAc also were tested as potential pheromone components. Addition of ( Z)-13-hexadecen-1-ol significantly reduced the number of males captured, and (Z)-13-hexadecenal had no effect on the attractiveness of the lure. These results suggest that the female-produced sex pheromone of H. submarginale is Z13-16:OAc. This hexadecenyl acetate is a novel moth sex pheromone component. [ABSTRACT FROM AUTHOR]

We investigated the interspecific variation of silver nanoparticle (SNP) sensitivity in common cladocerans ( Daphnia magna, D. galeata, and Bosmina longirostris) and the exact cause of both acute and chronic toxicity focusing on the form of silver (NPs and ions). Materials tested were non-surface-coated silver nanocolloids (SNCs) and AgNO. The results of the acute toxicity tests support the theory that the effects of SNPs on aquatic organisms is mainly due to Ag released from SNPs. Among the three cladocerans, D. galeata was more sensitive to silver (as Ag) than both D. magna and B. longirostris. Moreover, the chronic toxicity of SNCs was also derived from dissolved silver (especially Ag). SNCs (as total silver concentration) showed far lower chronic compared with acute toxicity to daphnids because the amount of dissolved silver decreased in the presence of prey algae. The chronic end-point values (EC values for net reproductive rate and the probability of survival to maturation) did not differ largely from acute ones (48-h EC obtained from acute toxicity tests and 48-h LC estimated by the biotic ligand model) when the values were calculated based on Ag concentration. The α value (concentration at which intrinsic population growth rate is decreased to zero) estimated by a power function model was a reliable parameter for assessing the chronic toxicity of silver. [ABSTRACT FROM AUTHOR]

While 11 species in the family Saturniidae are found in Japan, no sex pheromones of the native species had been investigated previously. We collected larvae of Rhodinia fugax in Nagano and Tottori Prefecture, and of Loepa sakaei in Okinawa Prefecture, and extracted sex pheromones of these two species from virgin female moths. In gas chromatography-electroantennogram detection (GC-EAD) analyses, male antennae of each species responded to one component in the respective pheromone extracts of conspecific females. Chemical analyses of the extracts by GC/mass spectrometry revealed that the EAD-active compounds of R. fugax and L. sakaei were a hexadecadienal and a tetradecadienyl acetate, respectively. The two species belong to the subfamily Saturniinae, and the mass spectra of both were similar to that of the 6,11-hexadecadienyl acetate identified from Antheraea polyphemus, classified in the same subfamily, suggesting the same 6,11-dienyl structure for the C aldehyde and a 4,9-dienyl structure for the C acetate. Based on this assumption, four geometrical isomers of each dienyl compound were stereoselectively synthesized via acetylene intermediates, compared to the natural products, and tested in the field. Male catches confirmed the pheromone structures of the two Japanese saturniid species as (6 E,11 Z)-6,11-hexadecadienal for R. fugax and (4 E,9 Z)-4,9-tetradecadienyl acetate for L. sakaei. The compounds have a characteristic 1,6-dienyl motif common to the pheromones of Saturniinae species. [ABSTRACT FROM AUTHOR]

We present a novel framework for estimating site-specific effects of pollutants on natural populations. Our method is based on fitness optimization and uses observed differences in tolerance (sensitivity) to a particular pollutant between populations at contaminated and uncontaminated sites (i.e., target and reference populations). In addition, the method uses laboratory estimates of the fitness cost of tolerance, that is, the reduction of population growth rate (fitness) of a target population compared to that of a reference population when both are maintained in uncontaminated conditions. As a case study, we applied this framework to analyze observed genetic differentiation in tolerance to the pyrethroid insecticide fenvalerate between Daphnia galeata populations in Lake Kasumigaura and an adjacent agricultural pond. The estimated exposure level at the contaminated site was about 0.015 μg/L, and the population-level risk corresponded to about a 24 % reduction of the intrinsic rate of natural increase. [ABSTRACT FROM AUTHOR]

Cyclosa spiders attach prey carcasses as decorations to their webs, but the functions of the carcasses are unclear and controversial. We investigated distinctive features of these webs in the field and conducted prey-capture experiments in the lab using the orb-web spider Cyclosa mulmeinensis. Webs with attached decoration had a significantly narrower mesh width than those without decoration and a higher degree of vertical asymmetry in the web's shape. In the laboratory, webs without decorations trapped significantly more prey, even though other features of the webs were nearly identical. These results suggest that web decorations do not attract prey in this species, but might play other roles such as blinding predators to the spider's presence. [ABSTRACT FROM AUTHOR]