Seasonal morphotypes of <i>Drosophila suzukii</i> differ in key life-history traits during and after a prolonged period of cold exposure

Seasonal polyphenism in Drosophila suzukii manifests itself in two discrete adult morphotypes, the “winter morph” (WM) and the “summer morph” (SM). These morphotypes are known to differ in thermal stress tolerance, and they co-occur during parts of the year. In this study, we aimed to estimate morph-specific survival and fecundity in laboratory settings simulating field conditions. We specifically analyzed how WM and SM D. suzukii differed in mortality and reproduction during and after a period of cold exposure resembling winter and spring conditions in temperate climates. The median lifespan of D. suzukii varied around 5 months for the WM flies and around 7 months for the SM flies. WM flies showed higher survival during the cold-exposure period compared with SM flies, and especially SM males suffered high mortality under these conditions. In contrast, SM flies had lower mortality rates than WM flies under spring-like conditions. Intriguingly, reproductive status (virgin or mated) did not impact the fly survival, either during the cold exposure or during spring-like conditions. Even though the reproductive potential of WM flies was greatly reduced compared with SM flies, both WM and SM females that had mated before the cold exposure were able to continuously produce viable offspring for 5 months under spring-like conditions. Finally, the fertility of the overwintered WM males was almost zero, while the surviving SM males did not suffer reduced fertility. Combined with other studies on D. suzukii monitoring and overwintering behavior, these results suggest that overwintered flies of both morphotypes could live long enough to infest the first commercial crops of the season. The high mortality of SM males and the low fertility of WM males after prolonged cold exposure also highlight the necessity for females to store sperm over winter to be able to start reproducing early in the following spring.</p

Erratum to: Non-crop plants used as hosts by Drosophila suzukii in Europe

n/

Radiofrequency for chronic lumbosacral and cervical pain:Results of a consensus study using the RAND/UCLA appropriateness method

Background: Despite the routine use of radiofrequency (RF) for the treatment of chronic pain in the lumbosacral and cervical region, there remains uncertainty on the most appropriate patient selection criteria. This study aimed to develop appropriateness criteria for RF in relation to relevant patient characteristics, considering RF ablation (RFA) for the treatment of chronic axial pain and pulsed RF (PRF) for the treatment of chronic radicular pain. Methods: The RAND/UCLA Appropriateness Method (RUAM) was used to explore the opinions of a multidisciplinary European panel on the appropriateness of RFA and PRF for a variety of clinical scenarios. Depending on the type of pain (axial or radicular), the expert panel rated the appropriateness of RFA and PRF for a total of 219 clinical scenarios. Results: For axial pain in the lumbosacral or cervical region, appropriateness of RFA was determined by the dominant pain trigger and location of tenderness on palpation with higher appropriateness scores if these variables were suggestive of the diagnosis of facet or sacroiliac joint pain. Although the opinions on the appropriateness of PRF for lumbosacral and cervical radicular pain were fairly dispersed, there was agreement that PRF is an appropriate option for well-selected patients with radicular pain due to herniated disc or foraminal stenosis, particularly in the absence of motor deficits. The panel outcomes were embedded in an educational e-health tool that also covers the psychosocial aspects of chronic pain, providing integrated recommendations on the appropriate use of (P)RF interventions for the treatment of chronic axial and radicular pain in the lumbosacral and cervical region. Conclusions: A multidisciplinary European expert panel established patient-specific recommendations that may support the (pre)selection of patients with chronic axial and radicular pain in the lumbosacral and cervical region for either RFA or PRF (accessible via https://rftool.org). Future studies should validate these recommendations by determining their predictive value for the outcomes of (P)RF interventions.</p

Overwintered <i>Drosophila suzukii</i> are the main source for infestations of the first fruit crops of the season

The mechanisms allowing the widespread invasive pest Drosophila suzukii to survive from early spring until the availability of the first fruit crops are still unclear. Seasonal biology and population dynamics of D. suzukii were investigated in order to better understand the contribution of the early spring hosts to the infestation of the first fruit crops of the season. We identified hosts available to D. suzukii in early spring and assessed their suitability for the pest oviposition and reproductive success under field and laboratory conditions. The natural infestation rate of one of these hosts, Aucuba japonica, was assessed over springtime and the morphology of the flies that emerged from infested A. japonica fruits was characterized under field conditions. Then, these findings were correlated with long-term monitoring data on seasonal reproductive biology and morphology of the pest, using a cumulative degree-days (DD) analysis. Field sampling revealed that overwintered D. suzukii females were physiologically able to lay eggs at 87 DD which coincided with the detection of the first infested early spring hosts. The latter were continuously and increasingly infested by D. suzukii eggs in nature from early spring until the end of May, in particular Aucuba japonica. Individuals emerged from most of these hosts were characterized by a poor fitness and a rather low success of emergence. In the field, only few summer morphs emerged from naturally infested A. japonica fruits around the end of May-beginning of June. However, field monitoring in orchards revealed that D. suzukii individuals consisted solely of winter morphs until mid-June. These observations indicate that overwintered D. suzukii females are the predominant source for the infestations in the first available fruit crops of the season. We discuss these findings in the context of possible pest control strategies

A review of the apple sawfly, hoplocampa testudinea (Hymenoptera tenthredinidae)

The apple sawfly (ASF), Hoplocampa testudinea Klug (Hymenoptera Tenthredinidae), attacks only one host plant, the apple tree (Malus domestica Borkh.). It is found in temperate regions of Europe as well as in Eastern North America. The flight of the ASF adults coincides with the bloom of apple trees and larvae develop in fruitlets. As the ASF spends approximately 11 months of its life cycle underground as a pre-pupa or pupa, management of the ASF is possible only during 1 month. The ASF is univoltine and has an obligatory diapause that can be extended to 2, 3 or rarely 4 years. Here key publications about the ASF have been selected for their relevance to the application of Integrated Pest Management programs. Because the ASF is dependent on living and developing tissues and because no oviposition or artificial diet is available for laboratory experimentations, research projects have to be conducted in field or semi-field conditions. The main natural mortality factors are the ichneumonid parasitoids Lathrolestes ensator (Brauns), present in Europe and introduced to Eastern Canada, and Aptesis nigrocincta (Gravenhorst) in Europe. The latter also acts as a hyperparasitoid of L. ensator. Management of the ASF can be based on monitoring adults with sticky traps and with use of a simulation model. Non-insecticidal methods that can be used deliberately in an ASF management program are reviewed, notably nematodes, entomopathogenic fungi, and physical control methods such as cellulose barriers and exclusion netting. The technical and economic reasons preventing widespread implementation of these approaches are discussed.</p

Replication Data for: Seasonal morphotypes of Drosophila suzukii differ in key life history traits during and after a period of cold exposure

R-scripts and corresponding .csv data files for statistical analyses. Abbreviations used in the csv. files: WM:Winter Morph SM:Summer Morph EM:Pre-cold mated LM:Post-cold mated V:Virgin F:Female M:Male </ul