Comparison of attractants for monitoring Drosophila suzukii in sweet cherry orchards in Italy

The invasiveness of Drosophila suzukii Matsumura is causing sizable damage to soft fruits and cherry. In order to define a targeted strategy for D. suzukii management, it is important to have access to highly sensitive trapping tools for detection, monitoring and control that are also selective, practical in use, economic, and with low environmental impact. The aim of this study was to compare different combinations of traps and lures to define a best practice approach for D. suzukii monitoring in Italy, extended over a wide elevational gradient and landscape complexity. The high attractiveness was not always combined with high selectivity, as in some cases up to 95% of the Drosophila spp. captured were belonging to species different from D. suzukii. The commercial Droso‐Trap was very efficient providing high capture ability. Overall, the most attractive lure was Droskidrink while Suzukii Trap was the most selective one. Lure attractiveness and selectivity, however, changed during the season in relation to environmental temperatures and phenological developmental stages, suggesting the need for implementing different lures in different periods and for the different purposes (monitoring or mass trapping). In terms of trap management, Droskidrink showed the problem of bacterial‐gel formation, while Suzukii Trap and Pherocon SWD were easier to handle as they did not need to be checked at weekly interval. Finally, these results were gathered to convey the most efficient combination of trap and bait able to efficiently perform mass trapping and attract and kill technique.     

Occurrence of some Glomales in Finland

By using trap plants, 17 species of arbuscular mycorrhizal fungi (AMF) belonging to the order Glomales were identified in 266 soil samples collected in the period 1987–1989. Of the identified isolates, 87.1% belonged to the genus Glomus Tulasne & Tulasne, 8.5% to Acaulospora Gerdemann & Trappe, 4.1% to Scutellospora Walker & Sanders and 0.3% to Entrophospora. Of the individual species identified, Glomus hoi Berch & Trappe was the most frequently identified, followed by G. fistulosum Skou & Jakobsen and G. mosseae (Nicol. & Gerd.) Gerdemann & Trappe. Only small differences in AMF trapping ability were observed between the four trap plants used, Trifolium pratense L., Zea mays L., Allium cepa L. var. cepa and Fragaria x ananassa Duch. T. pratense was chosen for further study because it had the highest AMF sporulation index in trap cultures and it also performed better than the other plants when grown in soils with different physical and chemical properties. The proportion of soil samples where AMF were identified decreased from close to 100% in the southern and central parts of Finland to about 50% in northern Finland.     

Revisiting within-tree trap positioning for apple maggot fly (Dipt., Tephritidae) behavioural control

Abstract:  Aiming to minimize visual competition between large red apples and red sphere traps from influencing effectiveness of traps for apple maggot fly (AMF) control, we compared AMF captures by red spheres in standard recommended position (no fruit within 15 cm), red spheres in similar position but with all fruit removed within a 30-cm radius (fruitless), red spheres with additional visual competition provided by three plastic red spheres hung 15 cm from sphere traps, and yellow panels. Traps were coated with adhesive, baited with synthetic fruit odour, and hung on trees of an apple cultivar bearing red fruit (Akeene) and trees of an apple cultivar bearing pale yellow fruit (Golden Delicious). On Akeene trees, red spheres in recommended position and fruitless red spheres caught more AMF than red spheres surrounded by plastic spheres and than yellow panels. Towards harvest, effectiveness of red spheres in recommended position decreased as reflectance of the surface of Akeene apples approached that of red spheres. By contrast, effectiveness of fruitless spheres increased over time. On Golden Delicious trees, fruitless spheres were the most effective, followed by spheres surrounded by uncoated plastic spheres and red spheres in recommended position. We conclude that removing all fruit within a 30-cm radius around red sphere traps results in similar or increased trap effectiveness relative to red spheres in recommended position.     

Rapid turnover of traps in Utricularia vulgaris L.

Summary Utricularia vulgaris growing at Wicken Fen, England, showed rapid turnover of the trapping apparatus. New groups of leaves, each bearing many traps, were produced at a rate of 1.4–2.8 groups per day from April to September, 1987. Old leaves decayed at a comparable rate, so that individual leaves survived for less than 50 days. In July, trapping efficiency of individual bladders was greatest between 1 and 6 days of age and then declined rapidly. Very few traps more than 19 days old could capture prey and most were lost from the leaves within 32 days. The lifespan of traps was closely related to their size and position on the leaves. Because of the rapidity of changes in trap condition with age, trap age is a vital consideration in any studies of the functional ecology of U. vulgaris     

Comparison of life tables between the solitary eumenid waspAnterhynchium flavomarginatum and the subsocial eumenid waspOrancistrocerus drewseni to evaluate the adaptive significance of maternal care

I compared life tables between the solitary eumenid wasp Anterhynchium flavomarginatumSmith and the subsocial eumenid wasp Orancistrocerus drewseniSaussure in Kyoto, Japan, during 1980–1983. The subsocial eumenid is parthenogenetic in this study area. There were 9 identified mortality factors in the solitary eumenid and 7 in the subsocial eumenid, 6 of which were common to the two eumenids. The important differences of mortality between the two eumenids were seen in the egg, larval, and prepupal stages. In the egg stage, mortality by the phorid fly Megaselia sp. was much lower in the subsocial eumenid (1.4%) than in the solitary eumenid (15.0%) likely because of the matenal care of the subsocial eumenid (progressive provisioning and other related behavior), which reduced predation pressure. In the larval stage, mortality by the miltogrammine fly Amobia distorta was also lower in the subsocial eumenid (8.1%) than in the solitary eumenid (23.8%) also probably because of the maternal care of the subsocial eumenid. A comparison of mortality in the two eumenids between the stable, long continuing natural nest sites and the additional temporal ones showed that the phorid fly remained near its birth place and parasitized stable nest sites. The miltogrammine fly followed returning eumenid wasps and parasitized those nest sites that have a high host density. In the prepupal stage, mortality by endogenous death was higher in the subsocial eumenid than in the solitary eumenid. Mortality due to the rhipiphorid beetle was also higher in the subsocial eumenid probably due to more frequent flower-visits by the subsocial eumenid. The defense mechanism of the subsocial eumenid was discussed in relation to the evolution of subsociality.     

Analytical studies of light trap records in the Hokuriku district,II the green rice leafhopper,Nephotettix cincticeps

Light-trap records on the green rice leafhopper, Nephotettix cincticeps, were dealt with to study its population fluctuations in the Hokuriku district. Crude data were modified for distinguishing years of the low intensity of infestation by the insect from the rest of years. It is then clearly demonstrated that the low intensity of infestation were ordinarily preceded by heavy snowfall, although heavy snowfall could not be regarded as the only factor checking the vigorous multiplication of the populations.     

Behavioural and chemical ecology underlying the success of turnip rape (Brassica rapa) trap crops in protecting oilseed rape (Brassica napus) from the pollen beetle (Meligethes aeneus)

There is increasing interest in the use of trap crops as components of integrated pest management (IPM) strategies. Understanding the mechanisms underlying host plant preferences of herbivorous pests can lead to improved effectiveness and reliability of the trap crop. We investigated the behavioural and chemical ecology underlying the success of turnip rape, Brassica rapa, trap crops in protecting oilseed rape, Brassica napus, from the pollen beetle, Meligethes aeneus, which feeds in the flowers and lays its eggs in the buds causing yield loss. Using a semi-field arena bioassay, plant growth stage was found to be a major factor in the preference of this pest for B. rapa over B. napus. Plants at early-flowering growth stages were preferred over plants in the bud stage, irrespective of species. No preference was found when both species were flowering. As B. rapa develops faster than B. napus in the field, this could explain part of the mechanism of its success as a trap crop. However, B. rapa was preferred over B. napus when both species were in the bud stage, indicating some inherent preferences for B. rapa. Responses of M. aeneus in olfactometer tests to the odours of B. napus and B. rapa at the bud and flowering growth stages, reflected those of the semi-field arena bioassay. These behavioural responses can be explained by volatile compounds associated with the flowering stage. Phenylacetaldehyde, indole and (E,E)-α-farnesene were found to be present in air entrainment samples of both plant species at the flowering growth stage, but only in those of B. rapa at the bud stage. The former two compounds were behaviourally-active in olfactometer tests. These compounds are likely to be involved in host location by M. aeneus, and, at least partially, responsible for the attractiveness of B. rapa and its success as a trap crop to protect B. napus from this pest.     

Single Nucleotide Polymorphism that Accompanies a Missense Mutation (Gln488His) Impedes the Dimerization of Hsp90

A single nucleotide polymorphism (SNP) that causes a missense mutation of highly conserved Gln488 to His of the α isoform of the 90-kDa heat shock protein (Hsp90α) molecular chaperone is observed in Caucasians. The mutated Hsp90α severely reduced the growth of yeast cells. To investigate this molecular mechanism, we examined the domain–domain interactions of human Hsp90α by using bacterial 2-hybrid system. Hsp90α was expressed as a full-length form, N-terminal domain (residues 1–400), or middle (residues 401–617) plus C-terminal (residues 618–732) domains (MC domain/amino acids 401–732). The Gln488His substitution in MC domain did not affect the intra-molecular interaction with N-terminal domain, whereas the dimeric interaction-mediated by the inter-molecular interaction between MC domains was decreased to 32%. Gln488Ala caused a similar change, whereas Gln488Thr, which exceptionally occurs in mitochondrial Hsp90 paralog, fully maintained the dimeric interaction. Therefore, the SNP causing Gln488His mutation could abrogate the Hsp90 function due to reduced dimerization.     

Actin Cross-link Assembly and Disassembly Mechanics for α-Actinin and Fascin

Self-assembly of complex structures is commonplace in biology but often poorly understood. In the case of the actin cytoskeleton, a great deal is known about the components that include higher order structures, such as lamellar meshes, filopodial bundles, and stress fibers. Each of these cytoskeletal structures contains actin filaments and cross-linking proteins, but the role of cross-linking proteins in the initial steps of structure formation has not been clearly elucidated. We employ an optical trapping assay to investigate the behaviors of two actin cross-linking proteins, fascin and α-actinin, during the first steps of structure assembly. Here, we show that these proteins have distinct binding characteristics that cause them to recognize and cross-link filaments that are arranged with specific geometries. α-Actinin is a promiscuous cross-linker, linking filaments over all angles. It retains this flexibility after cross-links are formed, maintaining a connection even when the link is rotated. Conversely, fascin is extremely selective, only cross-linking filaments in a parallel orientation. Surprisingly, bundles formed by either protein are extremely stable, persisting for over 0.5 h in a continuous wash. However, using fluorescence recovery after photobleaching and fluorescence decay experiments, we find that the stable fascin population can be rapidly competed away by free fascin. We present a simple avidity model for this cross-link dissociation behavior. Together, these results place constraints on how cytoskeletal structures assemble, organize, and disassemble in vivo.