International audience1.Insects are highly dependent on ambient temperatures to ensure their biological functions. Their persistence in the environment and their resistance to unfavorable temperatures are governed by their physiological thermal tolerance.2.Global change extends beyond climatic conditions to encompass modifications to the landscape. However, studies of climate change and landscape composition effects on ecosystem services, such as biological control, are commonly performed independently. Moreover, coarse scales are not always relevant when assessing climate change’s impacts on ectotherms. We aimed to better understand the ecological relationships that may exist between microclimatic variation and insect thermal tolerance across a landscape composition gradient. 3.To determine how landscape composition may impact insect thermal tolerance, parasitic wasps (Hymenoptera: Braconidae: Aphidiinae) of aphids were sampled along a landscape gradient from “closed” to “open” habitats. Sampling was performed during the winter 2013/14 and spring 2014 in cereal fields of Brittany, France. Meteorological data were recorded along this gradient. 4.First, our results show an influence of landscape composition on local microclimate. Additionally, parasitoids from open landscapes had a higher tolerance to low temperatures, leading to higher physiological costs, compared to parasitoids from closed landscapes. This trend was stronger in winter than in spring. 5.These results have numerous implications in the context of climate change, suggesting that targeted landscape management practices could create sheltered microclimatic areas that reduce the physiological costs of thermal tolerance, and promote the persistence of biological control agents

International audienceIn agrosystems, the increase in non-crop plant diversity by habitat management in or around arable fields contributes to improved Conservation Biological Control. During winter, plant flower are often used as monospecific ground cover and are expected to die before flowering as a result of recurrent frost events. Decreases in minimal temperature due to climate change offers new possibilities for plants used in such sown cover crops to mature and flowers. Changes in plant phenology thus constitute an important environmental change with expected consequences for ecosystem functioning, such as biological control. In Brittany, where winter agricultural landscape is dominated by a mosaic of cereal and sown cover crops, we assessed the consequences of mustard (Synapis alba) flowering cover crops (MFCC) on aphid parasitism and food web structure in plots adjoining cereal crops, in contrast to plots close to spontaneous non-crop plants (SNCP) of the same field. Overall, aphid parasitism rate at the field scale was strong (60–70%), being 13% higher adjacent to the MFCC than closer to SNCP. In addition, there was no change in food web structure between the two distinct zones, enabling us to hypothesize that MFCC mostly constituted an alimentary patch. The positive effect on parasitism rate was significant but weak, as floral nectar of mustard is known to be of poor quality for parasitoids. Results highlight the potential advantages of adapting practices in response to actual changes in agrosystems. Increase floral diversity in sown cover crops could constitute a complementary method in management programs, by providing more alternative food resources, alternative hosts, and climatic refuge to enhance the Conservation Biological Control of parasitoid populations

BACKGROUND Neuropeptides are regulators of critical life processes in insects and, due to their high specificity, represent potential targets in the development of greener insecticidal agents. Fundamental to this drive is understanding neuroendocrine pathways that control key physiological processes in pest insects and the screening of potential analogues. The current study investigated neuropeptide binding sites of kinin and CAPA (CAPA‐1) in the aphids Myzus persicae and Macrosiphum rosae and the effect of biostable analogues on aphid fitness under conditions of desiccation, starvation and thermal (cold) stress. RESULTS M. persicae and M. rosae displayed identical patterns of neuropeptide receptor mapping along the gut, with the gut musculature representing the main target for kinin and CAPA‐1 action. While kinin receptor binding was observed in the brain and VNC of M. persicae , this was not observed in M. rosae . Furthermore, no CAPA‐1 receptor binding was observed in the brain and VNC of either species. CAP2b/PK analogues (with CAPA receptor cross‐activity) were most effective in reducing aphid fitness under conditions of desiccation and starvation stress, particularly analogues 1895 ( 2Abf ‐ Suc ‐FGPRLa) and 2129 ( 2Abf ‐ Suc ‐ A TPRIa), which expedited aphid mortality. All analogues, with the exception of 2139‐Ac, were efficient at reducing aphid survival under cold stress, although were equivalent in the strength of their effect. CONCLUSION In demonstrating the effects of analogues belonging to the CAP2b neuropeptide family and key analogue structures that reduce aphid fitness under stress conditions, this research will feed into the development of second generation analogues and ultimately the development of neuropeptidomimetic‐based insecticidal agents. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Insect pests of agricultural crops have establish immunological tolerance against fungal infection caused by pathogens via different humoral and cellular processes. Fungal infection can be prevented by insect antioxidant and detoxifying enzymes, but there is no clear understanding of how they physiologically and biochemically interact. Our study aims to examine the antioxidant and detoxifying enzyme defense systems of the pest insect Spodoptera litura in response to infection by Metarhizium flavoviride. At 48 h following exposure to M. flavoviride, antioxidant enzyme levels were modified, and phenoloxidase and total hemocyte count were decreased significantly. The amount of detoxifying enzymes increased significantly. M. flavoviride appears to directly affect the S. litura immune system and results in decreased immunity. In a bioassay, M. flavoviride was found to be harmful to S. litura larvae in their third and fourth instar stage. M. flavoviride may be an effective tool in the control of S. litura larvae. Such entomopathogenic fungi represent cheaper, pollution free, target specific, promising alternatives to synthetic chemical tools in the for control insect pests.

BACKGROUNDNeuropeptides are central to the regulation of physiological and behavioural processes in insects, directly impacting cold and desiccation survival. However, little is known about the control mechanisms governing these responses in Drosophila suzukii. The close phylogenetic relationship of D. suzukii with Drosophila melanogaster allows, through genomic and functional studies, an insight into the mechanisms directing stress tolerance in D. suzukii.RESULTSCapability (Capa), leucokinin (LK), diuretic hormone 44 (DH44) and DH31 neuropeptides demonstrated a high level of conservation between D. suzukii and D. melanogaster with respect to peptide sequences, neuronal expression, receptor localisation, and diuretic function in the Malpighian tubules. Despite D. suzukii's ability to populate cold environments, it proved sensitive to both cold and desiccation. Furthermore, in D. suzukii, Capa acts as a desiccation‐ and cold stress‐responsive gene, while DH 44 gene expression is increased only after desiccation exposure, and the LK gene after nonlethal cold stress recovery.CONCLUSIONThis study provides a comparative investigation into stress tolerance mediation by neuroendocrine signalling in two Drosophila species, providing evidence that similar signalling pathways control fluid secretion in the Malpighian tubules. Identifying processes governing specific environmental stresses affecting D. suzukii could lead to the development of targeted integrated management strategies to control insect pest populations. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Traits of physiological thermotolerance are commonly measured in the laboratory as predictors of the field success of ectotherms at unfavourable temperatures (e.g. during harsh winters, heatwaves, or under conditions of predicted global warming). Due to being more complicated to measure, behavioural thermoregulation is less commonly studied, although both physiology and behaviour interact to explain the survival of ectotherms. The aphids Metopolophium dirhodum, Rhopalosiphum padi and Sitobion avenae are commercially important pests of temperate cereal crops. Although coexisting, these species markedly differ in winter success, with R. padi being the most abundant species during cold winters, followed by S. avenae and lastly M. dirhodum. To better understand the thermal physiology and behavioural factors contributing to differential winter success, the lethal temperature (physiological thermotolerance) and the behaviour of aphids in a declining temperature regime (behavioural thermotolerance) of these three species were investigated. Physiological thermotolerance significantly differed between the three species, with R. padi consistently the least cold tolerant and S. avenae the most cold tolerant. However, although the least cold tolerant of the study species, significantly more R. padi remained attached to the host plant at extreme sub-zero temperatures than S. avenae and M. dirhodum. Given the success of anholocyclic R. padi in harsh winters compared to its anholocyclic counterparts, this study illustrates that behavioural differences could be more important than physiological thermotolerance in explaining resistance to extreme temperatures. Furthermore it highlights that there is a danger to studying physiological thermotolerance in isolation when ascertaining risks of ectotherm invasions, the establishment potential of exotic species in glasshouses, or predicting species impacts under climate change scenarios.

1 Aphids, similar to all insects, are ectothermic and, consequently, are greatly affected by environmental conditions. The peach potato aphid Myzus persicae (Sulzer) has a global distribution, although it is not known whether populations display regional adaptations to distinct climatic zones along its distribution and vary in their ability to withstand and acclimate to temperature extremes. In the present study, lethal temperatures were measured in nine anholocyclic clones of M . persicae collected along a latitudinal cline of its European distribution from Sweden to Spain. The effects of collection origin and intra-and intergenerational acclimation on cold and heat tolerance, as determined by upper and lower lethal temperatures (ULT 50 and LLT 50 , respectively), were investigated. 2 Lethal temperatures of M. persicae were shown to be plastic and could be altered after acclimation over just one generation. Lower lethal temperatures were significantly depressed in eight of nine clones after acclimation for one generation at 10 • C (range: −13.3 to −16.2 • C) and raised after acclimation at 25 • C (range: −10.7 to −11.6 • C) compared with constant 20 • C (range: −11.9 to −12.9 • C). Upper lethal temperatures were less plastic, although significantly increased after one generation at 25 • C (range: 41.8-42.4 • C) and in five of nine clones after acclimation at 10 • C. There was no evidence of intergenerational acclimation over three generations. 3 Thermal tolerance ranges were expanded after acclimation at 10 and 25 • C compared with constant 20 • C, resulting in aphids reared at 10 • C surviving over a temperature range that was approximately 2-6 • C greater than those reared at 25 • C. 4 There was no clear relationship between lethal temperatures and latitude. Large scale mixing of clones may occur across Europe, thus limiting local adaption in thermal tolerance. Clonal type, as identified by microsatellite analysis, did show a relationship with thermal tolerance, notably with Type O clones being the most thermal tolerant. Clonal types may respond independently to climate change, affecting the relative proportions of clones within populations, with consequent implications for biodiversity and agriculture.

27Landscape changes are known to exacerbate the impacts of climate change. As such, 28 understanding the combined effect of climate and landscape on agro-ecosystems is vital if we 29 are to maintain the function of agro-ecosystems. The present study aimed to elucidate the 30 effects of agricultural landscape complexity on the microclimate and thermal tolerance of an 31 aphid pest to better understand how landscape and climate may interact to affect the thermal 32 tolerance of pest species within the context of global climate change. Meteorological data 33 were measured at the landscape level, and cereal aphids (Sitobion avenae, Metopolophium 34 dirhodum and Rhopalosiphum padi) sampled, from contrasting landscapes (simple and 35 complex) in winter 2013/14 and spring 2014 in cereal fields of Brittany, France. Aphids were 36 returned to the laboratory and the effect of landscape of origin on aphid cold tolerance (as 37 determined by CTmin) was investigated. Results revealed that local landscape complexity 38 significantly affected microclimate, with simple homogenous landscapes being on average 39 warmer, but with greater temperature variation. Landscape complexity was shown to impact 40 aphid cold tolerance, with aphids from complex landscapes being more cold tolerant than 41 those from simple landscapes in both winter and spring, but with differences among species. 42This study highlights that future changes to land use could have implications for the thermal 43 tolerance and adaptability of insects. Furthermore, not all insect species respond in a similar 44 way to microhabitat and microclimate, which could disrupt important predator-prey 45 relationships and the ecosystem service they provide. 46 47