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Body, M. J.

Publications and source records attributed to Body, M. J..

6 recordsLinked to original sources
bioRxiv2023

Population-specific responses to developmental temperature in the arboviral vector : implications for climate change

The increase of environmental temperature due to current global warming is not only favoring the expansion of the distribution range of many insect species, but it is also changing their phenology. Insect phenology is tightly linked to developmental timing, which is regulated by environmental temperatures. However, the degree to which effects of developmental temperatures extend across developmental stages and their inter-stage relationships have not been thoroughly quantified in mosquitoes. Here, we used the mosquito Aedes albopictus, which is an aggressive invasive species and an arboviral vector to study how developmental temperature influences fitness across developmental stages, thermal traits, energy reserves, transcriptome, and Wolbachia prevalence in populations from either temperate or tropical regions. We show that hatchability, larval and pupal viability, and developmental speed are strongly influenced by temperature and these effects extend to wing length, body mass, longevity, content of water, protein and lipids in adults, in a population-specific manner. On the contrary, neither adult thermal preference nor heat resistance significantly change with temperature. Development at 18{degrees}C revealed to be a limiting factor for the proliferation of Wolbachia in adults and transcriptome analysis showed enrichment for functions linked to stress responses (i.e. cuticle proteins and chitin, cytochrome p450, and heat shock proteins) in mosquitoes reared at both 18{degrees}C and 32{degrees}C. Our data showed an overall reduced vector fitness performance when mosquitoes were reared at 32{degrees}C, and the absence of isomorphy in the relationship between developmental stages and temperature in the temperate population. Altogether these results have important implications for reliable model projections of the invasion potentials of Ae. albopictus and its epidemiological impact.

ecology↗
bioRxiv2019

Field application of the geometric framework reveals a multistep strategy of nutrient regulation in a leaf-miner

Animals have evolved a vast array of behavioral and physiological strategies that allow them to achieve a nutritionally balanced diet. Plants as food for herbivores are often considered suboptimal, but phytophagous insects can employ pre- and post-ingestive mechanisms and/or symbiotic associations to help overcome food nutritional imbalances. This is particularly crucial for permanent multivoltine leaf-miner insects such as the caterpillar Phyllonorycter blancardella which completes development within a restricted area of a single leaf and use deciduous leaves to fuel growth and reproduction even under senescing autumnal conditions. Using the geometric framework for nutrition under natural field conditions, we show that this insect has multiple strategies to deal with inadequate food supply from the plant. First, larvae manipulate the protein-sugar content of both normal, photosynthetically active, and senescing, photosynthetically inactive, leaf tissues. Control of nutritional homeostasis of mined tissues is however higher for late instars, which differ from younger larval instars in their feeding mode (fluid-vs. tissue-feeder). Second, slight differences in the protein-sugar environment remain between mined tissues on green and yellow leaves despite this manipulation of the leaf physiology. This insect uses post-ingestive mechanisms to achieve similar body protein, sugar and lipid composition. This study demonstrates, for the first time under natural conditions, the ability of an insect herbivore to practice a combination of pre- and post-ingestive compensatory mechanisms to attain similar growth and metabolic outcomes in fundamentally different nutritional environments. Additionally, a comparison of larval nutritional requirements of 117 species from various insect groups further reinforces the hypothesis of a close association between P. blancardella and endosymbiotic bacteria for nutritional purposes.

ecology↗
bioRxiv2019

Manipulation of plant primary metabolism by leaf-mining larvae in the race against leaf senescence

Plants are often considered as suboptimal food for phytophagous insects, requiring them to employ various adaptive mechanisms to overcome food nutritional imbalances. This could include host-plant manipulation and/or symbiotic associations. The extensive reconfiguration of plant primary metabolism upon herbivory, as well as its impact on herbivores, have been largely overlooked, while studies investigating secondary metabolites is extensive. Here, we document how the apple leaf-mining caterpillar Phyllonorycter blancardella, a highly-specialized insect which completes development within a restricted area of a single Malus domestica leaf over successive different larval feeding modes, maintains nutrient-rich green tissues in its feeding area on green and senescent leaves. For this purpose, we quantified a large number of compounds involved in plant primary metabolism: starch, total soluble sugars, five individual sugars, twenty protein-bound amino acids and twenty free amino acids. Plant alteration can be observed not only on senescing (photosynthetically inactive) but also normal (photosynthetically active) leaf tissues of its host-plant to compensate for detrimental environmental variations. Our results show a differential control of the primary metabolism depending on the larva developmental stage, itself correlated to the fluid-feeding and tissue-feeding modes. Our results also suggest that leaf amino acid alterations favor a faster insect development. Finally, chemical scores indicate that the most growth-limiting essential amino acids are also common to other phytophagous insects and large herbivores, suggesting that these limitations are a general consequence of using plants as food source. We discuss the possible mechanisms responsible for these different manipulative capacities, as well as their ecological implications.

plant biology↗
bioRxiv2018

A galling insect activates plant reproductive programs during gall development

Some insects can redirect plant development to form unique organs called galls, which provide these insects with unique, enhanced food and protection from enemies and the elements. Many galls resemble flowers or fruits, suggesting that elements of reproductive development may be involved. We tested this hypothesis using RNA sequencing (RNAseq) to quantify the transcriptional responses of wild grapevine (Vitis riparia Michx.) leaves to a galling parasite, phylloxera (Daktulosphaira vitifolia (Fitch 1855)). If development of reproductive structures is part of gall formation, we expected to find significantly elevated expression of genes involved in flower and/or fruit development in developing galls as opposed to ungalled leaves. We found that reproductive gene ontology (GO) categories were significantly enriched in developing galls, and that expression of many candidate genes involved in floral development were significantly increased, particularly in later gall stages. The patterns of gene expression found in galls suggest that phylloxera exploits vascular cambium to provide meristematic tissue and redirects leaf development towards formation of carpels. The phylloxera leaf gall appears to be phenotypically and transcriptionally similar to the carpel, due to the parasite hijacking underlying genetic machinery in the host plant.

plant biology↗
bioRxiv2018

Underestimation of carbohydrates by sugar alcohols in classical anthrone-based colorimetric techniques compromises insect metabolic and energetic studies

Physiologically based metabolic studies usually search for easy, sensitive, and cheap techniques to rapidly estimate biological parameters such as nutrient content. Colorimetric methods to estimate carbohydrates have been extensively used (over 120,000 references). However, sugar alcohols are underestimated under conventionally used analytical conditions, in particular if using the popular van Handel method. This may lead to misinterpretations of sugar implications in biological systems. We determined the anthrone reaction with various sugar alcohols and non-alcohols individually under standard conditions (Van Handel 1985). We then manipulated the proportion of either sugar alcohols or non-alcohols in three different sugar mixtures in order to estimate the impact on the total sugar estimation. In the case of a mixture with over 50% of sugar alcohols, total sugars are underestimated by 50% when using glucose as standard.

ecology↗