scholarly journals The biology of the limnephilid caddisfly Dicosmoecus gilvipes (Hagen) in Northern California and Oregon (USA) Streams

Zoosymposia ◽  
2011 ◽  
Vol 5 (1) ◽  
pp. 413-419 ◽  
Author(s):  
Vincent H. Resh ◽  
Morgan Hannaford ◽  
John K. Jackson ◽  
Gary A. Lamberti ◽  
Patina K. Mendez
Keyword(s):  
Aquatic Insects ◽  
Sex Pheromones ◽  
Model Organism ◽  
Biotic Interactions ◽  
Northern California ◽  
Large Size ◽  
Behavioral Studies ◽  
Negative Effect ◽  
Males And Females ◽  
Dicosmoecus Gilvipes

The limnephilid caddisfly Dicosmoecus gilvipies (Hagen) occurs in many streams of northwestern United States and British Columbia.  Because of the large size of the fully grown larva, its synchronous emergence pattern, and its frequent imitation by fly-fishing anglers, D. gilvipes is one of the best known North American aquatic insects. Egg masses are found at the bases of Carex sedges. Cases of early larval instars are made of organic material and detritus; 3rd and 4th instars incorporate pebbles into cases. The 5th-instar case is made entirely of mineral material. Larvae can travel up to 25 m per day, and are predominantly scraper-grazers. Fifth instars attach their cases to the underside of boulders in mid-summer and remain dormant until pupation in autumn.  All northern California populations known are univoltine. Adult females use sex pheromones to attract males; most males come to trapped females in the 1st hour after sunset.  In laboratory studies, males and females fly during the mate attraction period but generally not at other times.  Males but not females exhibit circadian rhythms that govern flight periodicity. In enclosures to study biotic interactions, the density of D. gilvipes larvae has a negative effect on the densities of sessile grazers. This species has been widely used in trophic and behavioral studies conducted in the laboratory and field, and may be a model organism for ecological studies of caddisflies and other benthic macroinvertebrates.

A new species of Buenoa (Hemiptera: Heteroptera: Notonectidae) fromColombia

Zootaxa ◽  
2010 ◽  
Vol 2487 (1) ◽  
pp. 61
Author(s):  
DORA N. PADILLA-GIL
Keyword(s):  
Aquatic Insects ◽  
Aquatic Ecosystems ◽  
First Record ◽  
Western Hemisphere ◽  
South American ◽  
South American Species ◽  
Large Size ◽  
The Pacific ◽  
Males And Females ◽  
A New Species

Key words aquatic insects, high-Andean, south-west ColombiaIntroduction The genus Buenoa Kirkaldy has approximately 63 species and is restricted to the Western Hemisphere. In Colombia there are 14 species of Buenoa, and five species are located on the Pacific coast of Colombia in Tumaco, Nariño (PadillaGil, 2010). Buenoa funensis is described; it is the first record of the genus in high-Andean aquatic ecosystems, in the department of Nariño. In the department of Cundinamarca, Padilla-Gil (2002) found four species of Buenoa up to 1800 m above sea level, and just two species, B. pallipes (Fabricius) and B. cucunubensis Padilla-Gil & Nieser, were found at 3000 m. Buenoa funensis constitutes the first recording in Colombia of a large-size species, whose males measure more 8 mm of length; for this reason it is included within the five South American species and B. distincta from Mexico, which present this characteristic; and a key is presented to differentiate males and females of these species based on Nieser et al. (1997).

scholarly journals Age-Related Alterations in the Behavior and Serotonin-Related Gene mRNA Levels in the Brain of Males and Females of Short-Lived Turquoise Killifish (Nothobranchius furzeri)

Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1421
Author(s):  
Valentina S. Evsiukova ◽  
Elizabeth A. Kulikova ◽  
Alexander V. Kulikov
Keyword(s):  
Locomotor Activity ◽  
Body Mass ◽  
Mrna Level ◽  
Model Organism ◽  
The Body ◽  
Suitable Model ◽  
Mrna Levels ◽  
Age Related ◽  
Nothobranchius Furzeri ◽  
Males And Females

Short-lived turquoise killifish (Nothobranchius furzeri) have become a popular model organism for neuroscience. In the present paper we study for the first time their behavior in the novel tank diving test and the levels of mRNA of various 5-HT-related genes in brains of 2-, 4- and 6-month-old males and females of N. furzeri. The marked effect of age on body mass, locomotor activity and the mRNA level of Tph1b, Tph2, Slc6a4b, Mao, Htr1aa, Htr2a, Htr3a, Htr3b, Htr4, Htr6 genes in the brains of N. furzeri males was shown. Locomotor activity and expression of the Mao gene increased, while expression of Tph1b, Tph2, Slc6a4b, Htr1aa, Htr2a, Htr3a, Htr3b, Htr4, Htr6 genes decreased in 6-month-old killifish. Significant effects of sex on body mass as well as on mRNA level of Tph1a, Tph1b, Tph2, Slc6a4b, Htr1aa, 5-HT2a, Htr3a, Htr3b, Htr4, and Htr6 genes were revealed: in general both the body mass and the expression of these genes were higher in males. N. furzeri is a suitable model with which to study the fundamental problems of age-related alterations in various mRNA levels related with the brains 5-HT system.

scholarly journals Lagged Effect of Macroeconomic Variables on Stock Returns: A Case of Firm Size

2021 ◽  
Vol 19 (1) ◽  
Keyword(s):  
Stock Returns ◽  
Firm Size ◽  
Small Firms ◽  
Size Group ◽  
Negative Effects ◽  
Macroeconomic Factors ◽  
Large Size ◽  
Negative Effect ◽  
Positive Effect ◽  
Lagged Effect

The evidence of lagged effect regarding firm size between macroeconomic factors and stock returns is found with GARCH model for the UAE firms. More precisely, exchange rate showed a significant effect on stock returns irrespective of size group and lag level. However, a positive effect is observed at lag four and a negative effect is observed on lag five and two for small and large size firms respectively. For majority of the firms in small size, the risk-free rate showed a negative lagged effect on stock returns; however, for the majority of the firms in large size, it showed a positive lagged effect on stock returns. Inflation also showed a significant effect on stock returns on each lag level except for large firms where at lag five it is insignificant. Moreover, as the lags increase from 1- 4 and size from small to large, the negative effect of inflation converts to positive effect on stock returns. The lag effect of real activity showed both positive and negative effects on relatively larger stock returns of small firms than big firms. Money supply showed positive significant effect on stock returns of all firms irrespective of the size group; however, this relationship is even more prominent at lag five. Finally, the oil prices showed a positive effect on stock returns (large size) which further maximizes at lag two; whereas, a negative maximization takes place at lag three. Hence, investors can make informed and effective decisions and UAE policymakers developed effective measures to control and promote macroeconomic growth and stability.

Evidence for sex pheromones produced by males and females inBlatta orientalis (Dictyoptera, Blattidae)

1993 ◽  
Vol 19 (12) ◽  
pp. 2831-2853 ◽  
Author(s):  
Dehbia Abed ◽  
Remy Brossut ◽  
Jean -Pierre Farine
Keyword(s):  
Sex Pheromones ◽  
Males And Females

Mathematics anxiety and cognition: an integrated neural network model

2020 ◽  
Vol 31 (3) ◽  
pp. 287-296
Author(s):  
Ahmed A. Moustafa ◽  
Angela Porter ◽  
Ahmed M. Megreya
Keyword(s):  
Neural Network ◽  
Educational Outcomes ◽  
Mathematics Anxiety ◽  
Network Models ◽  
Neural Mechanism ◽  
Neural Network Models ◽  
Cognitive Studies ◽  
Behavioral Studies ◽  
Negative Effect ◽  
The Impact

AbstractMany students suffer from anxiety when performing numerical calculations. Mathematics anxiety is a condition that has a negative effect on educational outcomes and future employment prospects. While there are a multitude of behavioral studies on mathematics anxiety, its underlying cognitive and neural mechanism remain unclear. This article provides a systematic review of cognitive studies that investigated mathematics anxiety. As there are no prior neural network models of mathematics anxiety, this article discusses how previous neural network models of mathematical cognition could be adapted to simulate the neural and behavioral studies of mathematics anxiety. In other words, here we provide a novel integrative network theory on the links between mathematics anxiety, cognition, and brain substrates. This theoretical framework may explain the impact of mathematics anxiety on a range of cognitive and neuropsychological tests. Therefore, it could improve our understanding of the cognitive and neurological mechanisms underlying mathematics anxiety and also has important applications. Indeed, a better understanding of mathematics anxiety could inform more effective therapeutic techniques that in turn could lead to significant improvements in educational outcomes.

Energy allocation during the maturation of adults in a long-lived insect: implications for dispersal and reproduction

2015 ◽  
Vol 105 (5) ◽  
pp. 629-636 ◽  
Author(s):  
G. David ◽  
B. Giffard ◽  
I. van Halder ◽  
D. Piou ◽  
H. Jactel
Keyword(s):  
Egg Production ◽  
Model Organism ◽  
Energy Allocation ◽  
Dispersal Ability ◽  
Trade Off ◽  
Capital Breeder ◽  
Flight Capacity ◽  
Reproduction Process ◽  
Negative Effect ◽  
Investment In Reproduction

AbstractEnergy allocation strategies have been widely documented in insects and were formalized in the context of the reproduction process by the terms ‘capital breeder’ and ‘income breeder’. We propose here the extension of this framework to dispersal ability, with the concepts of ‘capital disperser’ and ‘income disperser’, and explore the trade-off in resource allocation between dispersal and reproduction. We hypothesized that flight capacity was sex-dependent, due to a trade-off in energy allocation between dispersal and egg production in females. We used Monochamus galloprovincialis as model organism, a long-lived beetle which is the European vector of the pine wood nematode. We estimated the flight capacity with a flight mill and used the number of mature eggs as a proxy for the investment in reproduction. We used the ratio between dry weights of the thorax and the abdomen to investigate the trade-off. The probability of flying increased with the adult weight at emergence, but was not dependent on insect age or sex. Flight distance increased with age in individuals but did not differ between sexes. It was also positively associated with energy allocation to thorax reserves, which increased with age. In females, the abdomen weight and the number of eggs also increase with age with no negative effect on flight capacity, indicating a lack of trade-off. This long-lived beetle has a complex strategy of energy allocation, being a ‘capital disperser’ in terms of flight ability, an ‘income disperser’ in terms of flight performance and an ‘income breeder’ in terms of egg production.

Effects of Water Absorption and Size of Superabsorbent Polymers on Internal Curing of Cement Paste

2013 ◽  
Vol 743-744 ◽  
pp. 193-197 ◽  
Author(s):  
Wen Bin Wang ◽  
Ji Ping Liu ◽  
Qian Tian ◽  
Yu Jiang Wang ◽  
Lei Li
Keyword(s):  
Water Absorption ◽  
Cement Paste ◽  
Autogenous Shrinkage ◽  
High Water ◽  
Internal Curing ◽  
Superabsorbent Polymers ◽  
Large Size ◽  
Negative Effect ◽  
The Relationship ◽  
Positive Effect

In recent years, superabsorbent polymers (SAPs) are considered as promising material for internal curing of cement-based materials, however, the relationship between SAPs structure and its performance are still unclear. In this paper, SAPs with different water absorption and size were selected to discuss their effect on autogenous deformation of cement paste and strength of mortars. Results indicated that SAPs with large-size and high-water absorption had positive effect on autogenous shrinkage reduction. The influence of SAPs on mortar mechanical properties revealed that SPAs seemed to have no negative effect on the strength of cement past. The increase of the strength might be from the decreased water/cement (w/c) ratio due to the water absorption by SAPs.

scholarly journals Desert mammal populations are limited by introduced predators rather than future climate change

2017 ◽  
Vol 4 (11) ◽  
pp. 170384 ◽  
Author(s):  
Aaron C. Greenville ◽  
Glenda M. Wardle ◽  
Chris R. Dickman
Keyword(s):  
Climate Change ◽  
Structural Equation ◽  
Regional Scale ◽  
Biotic Interactions ◽  
Future Climate Change ◽  
Introduced Predators ◽  
Negative Effect ◽  
Remote Camera ◽  
Rodent Prey

Climate change is predicted to place up to one in six species at risk of extinction in coming decades, but extinction probability is likely to be influenced further by biotic interactions such as predation. We use structural equation modelling to integrate results from remote camera trapping and long-term (17–22 years) regional-scale (8000 km 2 ) datasets on vegetation and small vertebrates (greater than 38 880 captures) to explore how biotic processes and two key abiotic drivers influence the structure of a diverse assemblage of desert biota in central Australia. We use our models to predict how changes in rainfall and wildfire are likely to influence the cover and productivity of the dominant vegetation and the impacts of predators on their primary rodent prey over a 100-year timeframe. Our results show that, while vegetation cover may decline due to climate change, the strongest negative effect on prey populations in this desert system is top-down suppression from introduced predators.

Trichodorus arasbaranensis n. sp. (Nematoda: Trichodoridae) from a natural forest in Arasbaran, north-west Iran

Nematology ◽  
2009 ◽  
Vol 11 (2) ◽  
pp. 243-252 ◽  
Author(s):  
Gholamreza Niknam ◽  
Akbar Karegar ◽  
Ebrahim Zahedi ◽  
Wilfrida Decraemer
Keyword(s):  
New Species ◽  
Excretory Pore ◽  
Large Body ◽  
Lateral View ◽  
Large Body Size ◽  
Pharyngeal Bulb ◽  
North West ◽  
Large Size ◽  
Cervical Papilla ◽  
Males And Females

AbstractTrichodorus arasbaranensis n. sp. is described from the rhizosphere of Carpinus betulus growing in forests in Arasbaran, north-west Iran. The new species is characterised by its large body length (1020-1520 μm in males; 1100-1500 μm in females), cuticle abnormally swollen upon fixation, onchiostyle medium-sized (41-66 μm in males; 49-65 μm in females) and secretory-excretory pore at level of pharyngeal bulb. Males have a single ventromedian cervical papilla varying in position from anterior to posterior to secretory-excretory pore, sperm cells with sausage-shaped nucleus, large (74-110 μm), smooth, ventrally curved spicules, manubrium wide, not offset from lamina, lamina narrowed in mid-region and with a distal ventral velum, and gubernaculum 25.5-34.5 μm long. Females have a short, but well developed, rounded vagina with large, rounded, triangular to oval-shaped, sclerotised vaginal pieces in lateral view. Because of its large body size, the new species most closely resembles T. magnus, T. elegans, T. obtusus, T. californicus and T. nanjingensis, from which the female can be differentiated by the short vagina length in relation to the corresponding body diam. and large size of the vaginal sclerotised pieces, and the male by the longer and differently shaped spicule which bears a velum. A key to the males and females of the Trichodorus spp. recorded from Iran is provided.

scholarly journals Fruit Flies (Drosophila spp.) Collection, Handling, and Maintenance: Field to Laboratory

2021 ◽  
Author(s):  
Pragya Topal ◽  
Divita Garg ◽  
Rajendra S. Fartyal
Keyword(s):  
Developmental Biology ◽  
Reproductive Biology ◽  
Cancer Biology ◽  
Life Sciences ◽  
Model Organism ◽  
Model Organisms ◽  
Chemical Studies ◽  
Males And Females ◽  
Species Specific ◽  
Food Media

As drosophilids are versatile, low maintenance and non-harming model organisms, they can be easily used in all fields of life sciences like Genetics, Biotechnology, Cancer biology, Genomics, Reproductive biology, Developmental biology, Micro chemical studies, ecology and much more. For using such a model organism, we need to learn capturing, rearing and culturing their progeny along with basic identification and differentiation between males and females. This chapter is being emphasized on techniques of capturing these flies with different and effective techniques. Along with it, most species-specific baits are discussed to catch more yield. Culture food media, a set measurement of different ingredients is used to rear the collected sample. The reasons for using each ingredient are also discussed in this chapter. At last, this chapter highlights the basic clues to identify different species in the field and lab along with learning distinguishing characteristics of males and females easily and effectively.

Sign in / Sign up

Export Citation Format

Share Document