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Journal of Insect Physiology

Daniela Römer, Martin Bollazzi, Flavio Roces
Social insects show temperature and humidity preferences inside their nests to successfully rear brood. In underground nests, ants also encounter rising CO2 concentrations with increasing depth. It is an open question whether they use CO2 as a cue to decide where to place and tend the brood. Leaf-cutting ants do show CO2 preferences for the culturing of their symbiotic fungus. We evaluated their CO2 choices for brood placement in laboratory experiments. Workers of Acromyrmex lundii in the process of relocating brood were offered a binary choice consisting of two interconnected chambers with different CO2 concentrations...
May 17, 2018: Journal of Insect Physiology
Ting-Ting Chen, Li-Rong Tan, Nan Hu, Zhan-Qi Dong, Zhi-Gang Hu, Ya-Ming Jiang, Peng Chen, Min-Hui Pan, Cheng Lu
Lysozymes is a ubiquitous immune effector that is widely distributed in both vertebrates and invertebrates. Previous reports have shown that lysozymes significantly inhibit viral infections in vertebrates. However, the antiviral effects of lysozymes in invertebrates remain unclear. Here, we investigated the role of lysozymes in Bombyx mori (B. mori) response to viral infection by overexpressing B. mori C-lysozyme (BmC-LZM) in larvae and cells. We found that BmC-LZM was up-regulated in cells in response to viral infection...
May 17, 2018: Journal of Insect Physiology
Juan Pedro Wulff, Natalia Capriotti, Sheila Ons
Ecdysis is a vital process for insects, during which they shed the old cuticle in order to emerge as the following developmental stage. Given its relevance for survival and reproduction, ecdysis is tightly regulated by peptidic hormones that conform an interrelated neuromodulatory network. This network was studied in species that undergo a complete metamorphosis, but not in hemimetabola. In a recent work, we demonstrated that orcokinin neuropeptides are essential for ecdysis to occur in the kissing bug Rhodnius prolixus...
May 17, 2018: Journal of Insect Physiology
Fabien J Démares, Christian W W Pirk, Susan W Nicolson, Hannelie Human
For two decades, neonicotinoid insecticides have been extensively used worldwide. Targeting neuronal receptors, they have deleterious effects on the behaviour and physiology of many of many beneficial as well as harmful insects. Bees are exposed to these insecticides in pollen and nectar while providing pollination services to agricultural crops, and neonicotinoids have been shown to impair navigation by bees and to decrease their foraging activity. We have previously reported the effect of dietary thiamethoxam on sucrose responsiveness of young worker bees...
May 15, 2018: Journal of Insect Physiology
Louise Walderdorff, Philippe Laval-Gilly, Antoine Bonnefoy, Jaïro Falla-Angel
Insect hemocytes play an important role in insects' defense against environmental stressors as they are entirely dependent on their innate immune system for pathogen defense. In recent years a dramatic decline of pollinators has been reported in many countries. The drivers of this declines appear to be associated with pathogen infections like viruses, bacteria or fungi in combination with pesticide exposure. The aim of this study was thus to investigate the impact of imidacloprid, a neonicotinoid insecticide, on the cellular immune response of two pollinators (Apis mellifera and Bombus terrestris) during simultaneous immune activation with LPS (lipopolysaccharide) of Escherichia coli...
May 11, 2018: Journal of Insect Physiology
Daniel Knebel, Yaniv Assaf, Amir Ayali
BACKGROUND: Monitoring neuronal activity in the intact behaving animal is most desired in neuroethological research, yet it is rarely straightforward or even feasible. Here we present the use of manganese enhanced magnetic resonance imaging (MEMRI), a technique allowing monitoring the activity of an animal's nervous system during specific behavioral patterns. Using MEMRI we were able to show activity in different ganglia of the central nervous system of intact locusts during walking RESULTS: We injected two groups of locusts with manganese, which serves as a magnetic contrast agent...
May 11, 2018: Journal of Insect Physiology
Susan M Villarreal, Sylvie Pitcher, Michelle E H Helinski, Lynn Johnson, Mariana F Wolfner, Laura C Harrington
Aedes aegypti is a vector of medically important viruses including those causing Zika, dengue, and chikungunya. During mating, males transfer a number of proteins and other molecules to the female and these components of the male ejaculate are essential in shifting female post-mating behaviors in a number of insect species. Because these molecules are highly variable by species, and female post-mating behavior by species is also varied, behavioral assays testing the function of the ejaculate are necessary before we can develop control strategies targeting the mating system to reduce mosquito populations...
May 3, 2018: Journal of Insect Physiology
Julie A Mustard, Valerie Alvarez, Sofy Barocio, Jamie Mathews, Alexander Stoker, Kashif Malik
Honey bees will learn to respond to an odor when their antennae are stimulated with sucrose, even if they are not fed during the conditioning phase. However, if they are not fed, the memory of this association is significantly reduced 24 h after conditioning. These results suggest that stimulation of proboscis with sucrose and/or the nutritional quality of the reward plays an important role in establishing a long lasting memory. Three sugars, xylose, sorbitol and mannitol, are used to investigate the relationship among learning, sensory perception and nutritional value...
May 2, 2018: Journal of Insect Physiology
M Lukas Seehausen, Paul-Henri Naumann, Catherine Béliveau, Véronique Martel, Michel Cusson
Encapsulation and melanisation are innate immune reactions of insects against foreign intruders such as parasitoids. In an earlier study, we observed that immature life stages of the endoparasitoid Tranosema rostrale (Hymenoptera: Ichneumonidae) parasitizing Choristoneura fumiferana (Lepidoptera: Tortricidae) larvae experienced higher mortality due to encapsulation and melanisation when reared at high (30°C) than at lower (10°C, 20°C) temperatures. Downregulation of T. rostrale polydnavirus genes in parasitized hosts and upregulation of two genes involved in the spruce budworm's melanisation process were identified as likely contributors to parasitoid mortality at high temperature...
April 25, 2018: Journal of Insect Physiology
Paula F Zermoglio, Marcela K Castelo, Claudio R Lazzari
The increase in body temperature over that of the environment has been frequently reported in insects, in particular in relation with flight activity. Scarab beetles of the genus Cyclocephala living in tropical areas are known to exploit the heat produced by thermogenic plants, also producing heat by endothermy. Here, we report the first case of endothermy in a species of this genus living in a temperate region, Cyclocephala signaticollis. We characterised the phenomenon in this beetle using infrared thermography and exposing them to different thermal conditions...
April 20, 2018: Journal of Insect Physiology
Anthony J Zera, Neetha Nanoth Vellichirammal, Jennifer A Brisson
The functional basis of life history adaptation is a key topic of research in life history evolution. Studies of wing-polymorphism in the cricket Gryllus firmus have played a prominent role in this field. However, prior in-depth investigations of morph specialization have primarily focused on a single hormone, juvenile hormone, and a single aspect of intermediary metabolism, the fatty-acid biosynthetic component of lipid metabolism. Moreover, the role of diurnal variation in life history adaptation in G. firmus has been understudied, as is the case for organisms in general...
April 12, 2018: Journal of Insect Physiology
Martín M Pérez, Pablo A Bochicchio, Alejandro Rabossi, Luis A Quesada-Allué
After the emergence of the Ceratitis capitata imago, the pale and folded wings are expanded and sclerotized to acquire the definitive form and to stabilize the cuticle. The wings of this fly show a specific pattern of brownish and black spots. Black spots are pigmented by melanin, whereas there was scarce information about the development of the brownish spots. N-beta-alanydopamine (NBAD) is the main tanning precursor in C. capitata body cuticle, and we hypothesized that it may be responsible for the colouration of the brownish spots...
April 12, 2018: Journal of Insect Physiology
Emmanuel Kamba Mebourou, Balázs Bernáth, Dominique Schenker, Patrick M Guerin
Organisms respond to environmental stimuli in ways that optimize survival and reproduction. Tsetse fly life-history is characterized by high investment in progeny by the pregnant female and low birth rate. This places constraints on tsetse populations across the sub-Saharan biotopes they colonize where extreme climatic conditions militate against survival. Controlling metabolic rate is crucial in biotopes where daily swings in temperature can exceed 20 o C. Tsetse acquire their nutrient requirements from the blood meal...
April 9, 2018: Journal of Insect Physiology
Manolis Lirakis, Marlies Dolezal, Christian Schlötterer
Organisms regularly encounter unfavorable conditions and the genetic adaptations facilitating survival have been of long-standing interest to evolutionary biologists. Winter is one particularly stressful condition for insects, during which they encounter low temperatures and scarcity of food. Despite dormancy being a well-studied adaptation to facilitate overwintering, there is still considerable controversy about the distribution of dormancy among natural populations and between species in Drosophila. The current definition of dormancy as developmental arrest of oogenesis at the previtellogenic stage (stage 7) distinguishes dormancy from general stress related block of oogenesis at early vitellogenic stages (stages 8 - 9)...
April 9, 2018: Journal of Insect Physiology
Jin-Cheng Zheng, Shao-Lei Sun, Xiao-Rong Yue, Tong-Xian Liu, Xiangfeng Jing
Sterols are essential nutrients for eukaryotes. Insects are obligate sterol auxotrophs and must acquire this key nutrient from their diets. The digestive tract is the organ for absorbing nutrients as well as sterols from food. In mice, the Niemann-Pick type C1 Like 1 (NPC1L1) gene is highly expressed in the intestine and is critical for cholesterol absorption. In contrast, the molecular mechanisms for the absorption of dietary sterols in insects have not been well studied. We annotated NPC1 genes in 39 insects from 10 orders using available genomic and transcriptomic information and inferred phylogenetic relationships...
April 9, 2018: Journal of Insect Physiology
Allie B Cohen, Mariana F Wolfner
The ejaculatory bulb of Drosophila melanogaster males produces proteins and pheromones that play important roles in reproduction. This tissue is also the final mixing site for the ejaculate before transfer to the female. The ejaculatory bulb's dynamics remain largely unstudied. By microscopy of the ejaculatory bulb in maturing adult males, we observed that the ejaculatory bulb expands in size as males age. Moreover, we document that when males mate, their ejaculatory bulb expands further as ejaculate transfer begins, and then contracts halfway through the course of mating as ejaculate transfer finishes...
April 7, 2018: Journal of Insect Physiology
Yufang Deng, Fan Hu, Lili Ren, Xiwu Gao, Yuejin Wang
The oriental fruit fly (Bactrocera dorsalis) larvae may commonly experience a hypoxia microenvironment and have evolved the ability to survive in the low oxygen condition with some physiological and biochemical mechanisms. However, little is known about the response of B. dorsalis to hypoxia or anoxia. In this study, the effect of anoxia on the survival of B. dorsalis was investigated. The results showed that the B. dorsalis larvae were quite tolerant to anoxia conditions and can tolerate up to 24 h of anoxia exposure without a significant reduction in survival, 100% mortality was reached after 84 h of anoxia exposure...
April 7, 2018: Journal of Insect Physiology
Emad Ibrahim, Pavel Dobeš, Martin Kunc, Pavel Hyršl, Dalibor Kodrík
This study examined how adipokinetic hormone (AKH) and adenosine affect defense responses in Drosophila melanogaster larvae infected with entomopathogenic nematodes (EPN, Steinernema carpocapsae and Heterorhabditis bacteriophora). Three loss-of-function mutant larvae were tested: Akh1 , AdoR1 (adenosine receptor), and Akh1 AdoR1 . Mortality decreased in all mutants post-EPN infection compared with the control (w1118 ). Additionally, co-application of external AKH with EPN significantly increased mortality beyond rates observed in EPN-only treatment, while also elevating carbon dioxide production, a measure of metabolism...
April 5, 2018: Journal of Insect Physiology
Luisa Woestmann, Melanie Gibbs, Helen Hesketh, Marjo Saastamoinen
Infections represent a constant threat for organisms and can lead to substantial fitness losses. Understanding how individuals, especially from natural populations, respond towards infections is thus of great importance. Little is known about immunity in the Glanville fritillary butterfly (Melitaea cinxia). As the larvae live gregariously in family groups, vertical and horizontal transmission of infections could have tremendous effects on individuals and consequently impact population dynamics in nature. We used the Alphabaculovirus type strain Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and demonstrated that positive concentration-dependent baculovirus exposure leads to prolonged developmental time and decreased survival during larval and pupal development, with no sex specific differences...
April 5, 2018: Journal of Insect Physiology
Ze-Hua Wang, Rong-Min Hu, Xi-Qian Ye, Jian-Hua Huang, Xue-Xin Chen, Min Shi
Laccase (EC is a phenoloxidase found in many insect species. The Laccase 1 gene from Plutella xylostella (PxLac1) was cloned, and its expression patterns and functions were determined using qPCR and RNAi methods. The results showed that the expression levels of PxLac1 were consistently high in all larval stages, and the most abundant was in the midgut during the 4th instar stage. Moreover, the expression of PxLac1 was up-regulated in response to bacterial infection, and decreased 24 h after being parasitized by Cotesia vestalis...
April 4, 2018: Journal of Insect Physiology
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