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Journal of Insect Physiology

Lindsey J Gray, Stephen J Simpson, Michal Polak
Optimal life-history strategies are those that best allocate finite environmental resources to competing traits. We used the geometric framework for nutrition to evaluate life-history strategies followed by Drosophila melanogaster by measuring the condition-dependent performance of life-history traits, including the morphology of male secondary sexual characters, sex combs. We found that depending on their rearing environment flies faced different forms of trait trade-offs and accordingly followed different life-history strategies...
December 1, 2017: Journal of Insect Physiology
Jorge Mariano Collantes-Alegre, Florian Mattenberger, Miquel Barberà, David Martínez-Torres
Organisms exhibit a wide range of seasonal responses as adaptions to predictable annual changes in their environment. These changes are originally caused by the effect of the Earth's cycles around the sun and its axial tilt. Examples of seasonal responses include floration, migration, reproduction and diapause. In temperate climate zones, the most robust variable to predict seasons is the length of the day (i.e. the photoperiod). The first step to trigger photoperiodic driven responses involves measuring the duration of the light-dark phases, but the molecular clockwork performing this task is poorly characterized...
December 1, 2017: Journal of Insect Physiology
Fritz Prohaska, Karl H Joplin, Darrell Moore
In many animal species, circadian rhythms of behavior are not constant throughout the lifetime of the individual but rather exhibit at least some degree of plasticity. In the present study, we have examined the potential influences of gender, age, and nutrition (presence or absence of liver) on the expression of circadian locomotor activity rhythms in the flesh fly Sarcophaga crassipalpis. We found no significant differences in endogenous circadian period under constant dark conditions with respect to gender, nutrition, or age for the duration of our experiments...
November 21, 2017: Journal of Insect Physiology
Tommaso Manenti, Volker Loeschcke, Jesper Givskov Sørensen
Most research on thermal adaptation of ectotherms is based on experiments performed at constant temperatures. However, for short-lived insects daily fluctuations of temperature could be an important environmental parameter involved in evolutionary adaptation to thermal heterogeneity. In this study we investigated the mechanisms underlying evolutionary adaptation to daily fluctuating temperatures. We studied replicated selection lines of Drosophila simulans evolved in a constant or a daily fluctuating thermal regime...
November 21, 2017: Journal of Insect Physiology
Chun Chen, Sudan Ye, Huajun Hu, Chengmei Xue, Xiaoping Yu
A real-time qPCR method was developed, validated, and used to quantity the fungal pathogen, P. neoaphidis, within aphids at different times during infection; colonization rate fitted the Gompertz model well (R(b)=0.9356). Feeding behaviour of P. neoaphidis-infected and uninfected M. persicae were investigated, for the first time, using DC-electrical penetration graphs (DC-EPG) that characterized the waveforms made during different aphid stylet probing periods corresponding to epidermis penetration, salivation and ingestion...
November 10, 2017: Journal of Insect Physiology
Lauren E Des Marteaux, Joseph R Stinziano, Brent J Sinclair
Cold-acclimated insects maintain ion and water balance in the cold, potentially by reducing permeability or increasing diffusion distance across ionoregulatory epithelia such as the rectum. We explored whether cold acclimation induces structural modifications that minimize water and ion diffusion across the rectum and maintain rectal cell integrity. We investigated rectal structure and cytoskeletal stability in chill-susceptible adult Gryllus pennsylvanicus crickets acclimated for one week to either warm (25°C) or cold (12°C) conditions...
November 10, 2017: Journal of Insect Physiology
Shaohui Wu, Olga S Kostromytska, Fangsen Xue, Albrecht M Koppenhöfer
Diapausing adults of the annual bluegrass weevil, Listronotus maculicollis, were collected from their hibernating sites at different times in autumn and winter, and subjected to different conditions to observe diapause termination by dissecting and measuring the reproductive organs. When diapausing weevils were maintained under laboratory cold conditions (10 h light at 6°C:14 h dark at 4°C) from early December to late March, the sizes of reproductive organs of both sexes increased or fluctuated slightly, and very few females had developing oocytes, suggesting that most adults did not resume development during the chilling period...
November 10, 2017: Journal of Insect Physiology
Robert Potts, Rebecca M Clarke, Sophie E Oldfield, Lisa K Wood, Natalie Hempel de Ibarra, James E Cresswell
For bumble bees (genus Bombus), the capacity for non-flight thermogenesis is essential for two fundamental processes undertaken by adult workers, namely recovery from torpor after chilling and brood incubation. Farmland bees can be widely exposed to dietary residues of neurotoxic neonicotinoid insecticides that appear in the nectar and pollen of treated bee-attractive crops, which may harm them. An earlier study shows that dietary neonicotinoids cause complex alterations to thermoregulation in honey bees, but their effects on the thermogenic capabilities of individual bumble bees has been untested previously...
November 10, 2017: Journal of Insect Physiology
John M VandenBrooks, Gregory Gstrein, Jason Harmon, Jessica Friedman, Matthew Olsen, Anna Ward, Gregory Parker
Atmospheric oxygen is one of the most important atmospheric component for all terrestrial organisms. Variation in atmospheric oxygen has wide ranging effects on animal physiology, development, and evolution. This variation in oxygen has the potential to affect both respiratory systems (the supply side) and mitochondrial networks (the demand side) in animals. Insect respiratory systems supplying oxygen to tissues in the gas phase through blind ended tracheal systems are particularly susceptible to this variation...
November 6, 2017: Journal of Insect Physiology
Michala Korandová, Tomáš Krůček, Klára Szakosová, Dalibor Kodrík, Ronald P Kühnlein, Jindřiška Tomášková, Radmila Čapková Frydrychová
It has been proposed that oxidative stress, elicited by high levels of reactive oxygen species, accelerates telomere shortening by erosion of telomeric DNA repeats. While most eukaryotes counteract telomere shortening by telomerase-driven addition of these repeats, telomeric loss in Drosophila is compensated by retrotransposition of the telomeric retroelements HeT-A, TART and TAHRE to chromosome ends. In this study we tested the effect of chronic exposure of flies to non-/sub-lethal doses of paraquat, which is a redox cycling compound widely used to induce oxidative stress in various experimental paradigms including telomere length analyses...
November 6, 2017: Journal of Insect Physiology
Ken Sasaki, Hinako Matsuyama, Naruaki Morita, Masato Ono
A society of bumble bees is primitively eusocial, with an annual life cycle, and can be used as a physiological model of social bees for comparative studies with highly eusocial hymenopterans. We investigated the dynamics of biogenic amine levels in the brain, meso-metathoracic ganglia, terminal abdominal ganglion, and hemolymph in queens 1 day after mating (1DAM), during diapause (Dp), and during colony founding (CF) in the bumble bee, Bombus ignitus. Dopamine levels in the brain of CF queens were significantly lower than in 1DAM and Dp queens, and the levels in the thoracic ganglia and hemolymph in CF queens were lower than in 1DAM queens, but did not differ from other groups in the abdominal ganglion...
November 2, 2017: Journal of Insect Physiology
Travis L Calkins, Andrew DeLaat, Peter M Piermarini
In adult dipteran insects (flies), the crop is a diverticulum of the esophagus that serves as a food storage organ. The crop pumps stored contents into the alimentary canal for digestion and absorption. The pumping is mediated by peristaltic contractions of the crop musculature. In adult female mosquitoes, the crop (ventral diverticulum) selectively stores sugar solutions (e.g., nectar); proteinaceous blood meals by-pass the crop and are transferred directly to the midgut for digestion. The mechanisms that regulate crop contractions have never been investigated in mosquitoes...
October 28, 2017: Journal of Insect Physiology
Zhong-Jian Shen, Song-Dou Zhang, Yan-Jun Liu, Xiao-Ming Liu, Zhen Li, Qing-Wen Zhang, Xiao-Xia Liu
Glutaredoxins play crucial roles in maintaining intracellular redox homeostasis via scavenging of excess reactive oxygen species. In this study, a glutaredoxin domain-containing cysteine-rich gene from Helicoverpa armigera, named HaGdccr, was characterized. Sequence analysis revealed that it contains a glutaredoxin domain and a conserved cysteine and shares high sequence identity with other insect genes. HaGdccr mRNA expression was highest in molting larvae of the 3rd instar and was mainly detected in the central nervous system of larvae and the wings of adults...
October 21, 2017: Journal of Insect Physiology
Joanna K Konopka, Jeremy N McNeil
While pheromone traps have been effectively used to monitor the recent range expansion of the western bean cutworm (WBC), very little is known about the pheromone mediated reproductive biology of this species. The age at which females initiated calling (the behaviour associated with the release of the sex pheromone), and the pattern of calling on the first three nights following sexual maturation were determined for virgin females held under four temperature regimes (25:20; 25:15; 20:15; 20:10 °C L:D and 16L:8D photoperiod), and two RH (60 and 80%)...
October 20, 2017: Journal of Insect Physiology
Ning Li, Yaohua Li, Shize Zhang, Yongliang Fan, Tongxian Liu
A rise in atmospheric carbon dioxide concentration ([CO2]) and a warming climate are two of the most conspicuous characteristics of global climate change in this century. However, studies addressing the combined impact of rising [CO2] and temperature on herbivore insect physiology are still limited. In this study we investigated the combined effects of elevated [CO2] and temperature on major antioxidative enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidases (POD) and detoxification enzymes of glutathione-S-transferases (GST) and acetylcholinesterase (AChE) in three consecutive generations of Bemisia tabaci Middle East-Asia Minor 1 (MEAM1, commonly known as B biotype) adults...
October 19, 2017: Journal of Insect Physiology
Fanny Vogelweith, Susanne Foitzik, Joël Meunier
Immunity is a crucial but costly trait. Individuals should therefore adjust their investment into immunity to their condition and infection risks, which are often determined by their age, sex, mating status and social environment. However, whether and how these four key factors can interact to shape basal immunity remains poorly understood. Here, we tested the simultaneous effects of these factors on hemocyte concentration and phenoloxidase activity in adults of the European earwig. We found that hemocyte concentration increased with age, and that this increase was stronger in males...
October 14, 2017: Journal of Insect Physiology
Lucy Alford, Hossein Kishani Farahani, Jean-Sébastien Pierre, Françoise Burel, Joan van Baaren
For generalist parasitoids such as those belonging to the Genus Aphidius, the choice of host species can have profound implications for the emerging parasitoid. Host species is known to affect a variety of life history traits. However, the impact of the host on thermal tolerance has never been studied. Physiological thermal tolerance, enabling survival at unfavourable temperatures, is not a fixed trait and may be influenced by a number of external factors including characteristics of the stress, of the individual exposed to the stress, and of the biological and physical environment...
October 14, 2017: Journal of Insect Physiology
Didi Tarmadi, Tsuyoshi Yoshimura, Yuki Tobimatsu, Masaomi Yamamura, Toshiaki Umezawa
We investigated the effects of lignins as diet components on the physiological activities of a lower termite, Coptotermes formosanus Shiraki. Artificial diets composed of polysaccharides with and without purified lignins (milled-wood lignins) from Japanese cedar (softwood), Japanese beech (hardwood), and rice (grass), were fed to C. formosanus workers. The survival and body mass of the workers as well as the presence of three symbiotic protists in the hindguts of the workers were then periodically examined...
October 14, 2017: Journal of Insect Physiology
Leigh Boardman, Katherine A Mitchell, John S Terblanche, Jesper G Sørensen
While single stress responses are fairly well researched, multiple, interactive stress responses are not-despite the obvious importance thereof. Here, using D. melanogaster, we investigated the effects of simultaneous exposures to low O2 (hypoxia) and varying thermal conditions on mortality rates, estimates of thermal tolerance and the transcriptome. We used combinations of 21 (normoxia), 10 or 5kPa O2 with control (23°C), cold (4°C) or hot (31°C) temperature exposures before assaying chill coma recovery time (CCRT) and heat knock down time (HKDT) as measures of cold and heat tolerance respectively...
October 13, 2017: Journal of Insect Physiology
Bartosz W Schramm, Agnieszka Gudowska, Andrzej Antoł, Anna Maria Labecka, Ulf Bauchinger, Jan Kozłowski, Marcin Czarnoleski
The rate at which organisms metabolize resources and consume oxygen is tightly linked to body mass. Typically, there is a sub-linear allometric relationship between metabolic rates and body mass (mass-scaling exponent b<1). The origin of this pattern remains one of the most intriguing and hotly debated topics in evolutionary physiology. A decrease in mass-specific metabolic rates in larger organisms might reflect disproportionate increases in body components with low metabolic activity, such as storage and skeletal tissues...
October 12, 2017: Journal of Insect Physiology
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