scholarly journals A hymenopteran odorant alerts flies to bury eggs

2021 ◽  
Author(s):  
Shaun M Davis ◽  
Gregory T Chism ◽  
Megan M Maurer ◽  
Julio E Trejo ◽  
Ricardo J Garcia ◽  
...  
Keyword(s):  
Selective Pressure ◽  
Paper Wasps ◽  
Defensive Responses ◽  
Ant Predation ◽  
Avoidance Behaviors ◽  
Vinegar Fly ◽  
Long Chain Alcohol ◽  
Oviposition Strategies ◽  
Food Substrate ◽  
Better Than

Ants are ubiquitous and consume insects at all life stages, presumably creating a strong selective pressure for ant avoidance behaviors across insects. The insect egg stage can be especially defenseless against predation given that eggs are usually immobile and unguarded, suggesting insect mothers may have evolved oviposition strategies to minimize the ant predation risk to their offspring. Given the lack of parental care in most insects, these oviposition strategies would likely be innate rather than learned, since insect mothers are not usually present to assess predation of their eggs. Here, we use the vinegar fly Drosophila melanogaster as a model system for examining parental defensive responses to ant presence. Flies usually lay eggs partially inserted into the food substrate, although some are laid on top of the food and a few are inserted deeply into the food. We found that exposure to ants significantly alters fly oviposition depth: the proportion of eggs on the food surface decreased while the proportion of buried eggs increased. Buried eggs survive ant foraging bouts better than surface eggs, showing that this oviposition depth behavior is adaptive. This induced behavior is conserved across the genus Drosophila and is dependent on the fly olfactory system: anosmic mutant flies fail to bury their eggs in the presence of ants, and ant odor extracts are sufficient to induce egg burying. By fractionating ant body washes and using GC-MS to identify fraction constituents, we identified the saturated, long-chain alcohol 1-octadecanol as the odorant flies use to sense ant presence. To further delineate the ant lineages to which flies respond, we exposed flies to the odors from numerous species of ants and other insects. Surprisingly, flies buried their eggs in response to the odors of nearly all hymenopterans tested, including hymenopteran groups that flies rarely interact with in nature like bees and paper wasps. Our data suggest that 1-octadecanol is a conserved and ancient hymenopteran odorant, and that drosophilids evolved a mechanism for sensing this odorant early in their evolution as a means of protecting their offspring from ant predation. This study sheds light on the ecology and mechanisms underlying a common biotic interaction in nature, that between insect parents and the ants that would consume their offspring.

scholarly journals A neural circuit for competing approach and avoidance underlying prey capture

2020 ◽  
Author(s):  
Daniel Rossier ◽  
Violetta La Franca ◽  
Taddeo Salemi ◽  
Cornelius T. Gross
Keyword(s):  
Lateral Hypothalamus ◽  
Neural Circuit ◽  
Prey Capture ◽  
Gabaergic Neurons ◽  
Approach And Avoidance ◽  
Periaqueductal Grey ◽  
Defensive Responses ◽  
Avoidance Behaviors ◽  
Avoidance Responses

AbstractPredators must frequently balance competing approach and avoidance behaviors elicited by a moving and potentially dangerous prey. Several brain circuits supporting predation have recently been localized. However, the mechanisms by which these circuits balance the conflict between approach and avoidance responses remain unknown. Laboratory mice initially show alternating approach and avoidance responses toward cockroaches, a natural prey, but with repeated exposure become avid hunters. Here we used in vivo neural activity recording and cell-type specific manipulations in hunting mice to identify neurons in the lateral hypothalamus and periaqueductal grey that encode and control predatory approach and avoidance. We found a subset of GABAergic neurons in lateral hypothalamus that specifically encoded hunting behaviors and whose stimulation triggered predation, but not feeding. This population projects to the periaqueductal grey and stimulation of these projections promoted predation. Neurons in periaqueductal grey encoded both approach and avoidance behaviors, but only initially when the mouse showed high levels of fear of the prey. Our findings allow us to propose that GABAergic neurons in lateral hypothalamus facilitate predation in part by suppressing defensive responses to prey encoded in the periaqueductal grey. Our findings reveal a neural circuit mechanism for controlling the balance between conflicting approach and avoidance behaviors elicited by the same stimulus.

scholarly journals Cultivating Moina macrocopa Straus in different media using carotenogenic yeast Rhodotorula

2015 ◽  
Vol 23 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Olga Kushniryk ◽  
Oleksii Khudyi ◽  
Lidiia Khuda ◽  
Ryszard Kolman ◽  
Mykhailo Marchenko
Keyword(s):  
Rhodotorula Glutinis ◽  
Standard Medium ◽  
Fish Food ◽  
Moina Macrocopa ◽  
Live Feed ◽  
Recirculating Aquaculture ◽  
Production Water ◽  
Food Substrate ◽  
Better Than ◽  
Improved Characteristics

Abstract The possibility of using carotenogenic yeast from the genus Rhodotorula as food substrate was studied during the cultivation of Moina macrocopa. The results showed that replacing traditional food substrates during the cultivation of the live fish food M. macrocopa resulted in improved characteristics that were superior to the alternative. Using carotenogenic yeast Rhodotorula glutinis (Fres.) Harrison to stimulate carotenoid accumulation in live feed is better than R. rubra (Demme) Lodder. The optimal duration of enriching M. macrocopa with carotenoids was four days when using various types of yeast capable of carotenogenesis. Replacing the standard medium for culturing M. macrocopa with the alternative medium was less expensive. Breeding live feed on recirculating aquaculture system (RAS) post-production water was proven to be effective.

scholarly journals Component Thermodynamical Selection Based Gene Expression Programming for Function Finding

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Zhaolu Guo ◽  
Zhijian Wu ◽  
Xiaojian Dong ◽  
Kejun Zhang ◽  
Shenwen Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Machine Learning ◽  
Selective Pressure ◽  
Gene Expression Programming ◽  
Population Diversity ◽  
Minimal Free Energy ◽  
Slow Convergence ◽  
Benchmark Datasets ◽  
Function Finding ◽  
Better Than

Gene expression programming (GEP), improved genetic programming (GP), has become a popular tool for data mining. However, like other evolutionary algorithms, it tends to suffer from premature convergence and slow convergence rate when solving complex problems. In this paper, we propose an enhanced GEP algorithm, called CTSGEP, which is inspired by the principle of minimal free energy in thermodynamics. In CTSGEP, it employs a component thermodynamical selection (CTS) operator to quantitatively keep a balance between the selective pressure and the population diversity during the evolution process. Experiments are conducted on several benchmark datasets from the UCI machine learning repository. The results show that the performance of CTSGEP is better than the conventional GEP and some GEP variations.

scholarly journals Energetics of tent roosting in bats: the case of Ectophylla alba and Uroderma bilobatum (Chiroptera: Phyllostomidae).

2015 ◽  
Vol 97 (1) ◽  
pp. 246-252 ◽  
Author(s):  
Bernal Rodríguez-Herrera ◽  
Luis Víquez-R ◽  
Eugenia Cordero-Schmidt ◽  
Jean M. Sandoval ◽  
Armando Rodríguez-Durán
Keyword(s):  
Energy Expenditure ◽  
Heat Source ◽  
Ambient Temperature ◽  
Selective Pressure ◽  
Cocos Nucifera ◽  
Measured Temperature ◽  
Existing Structures ◽  
Roost Selection ◽  
Different Temperatures ◽  
Better Than

Abstract Roost selection in mammals is an important selective pressure, and many animals find shelter in previously existing structures. Furthermore, the microclimate of roosts is a crucial element for bat survival, and modified leaves are used for roosting (“tents”) by 22 species of bats. Our objective was to determine whether the inverted boat tents used by Ectophylla alba and pinnate tents used by Uroderma bilobatum provide energetic benefits. We measured the ambient temperature under modified and unmodified leaves (UMLs) of Heliconia imbricata and Cocos nucifera . We also measured temperature with (simulated bat presence) and without a heat source, and finally we measured bat energy expenditure at different temperatures. Our results show that when a heat source is present tents conserve heat better than a UML. The energy expenditure of E. alba and U. bilobatum increased up to 55% and 48%, respectively, with a decrease of temperature from 25°C to 20°C. We concluded that since the temperature at our study site drops below 25°C every night and remains that way until mid-morning, using a “tent” that maintains a temperature higher than ambient temperature, or close to 25°C degrees, provides an energetic advantage. La selección del refugio en los mamíferos es una presión selectiva importante y muchos animales encuentran refugio en estructuras ya existentes. El microclima del refugio es un elemento crucial para la sobrevivencia de los murciélagos. Las hojas modificadas (tiendas) son utilizadas por 22 especies de murciélagos. Nuestro objetivo era determinar si la tienda de bote invertido utilizada por Ectophylla alba y tiendas pinnadas utilizadas por Uroderma bilobatum brindan un beneficio energético a los murciélagos. Se midió la temperatura bajo hojas modificadas y no modificadas de Heliconia imbricata y Cocos nucifera . Además se midió la temperatura con fuente (simulando la presencia de murciélagos) y sin fuente de calor, finalmente se midió el gasto energético de los murciélagos a diferentes temperaturas. Los resultados muestran que cuando hay una fuente de calor presente, la tienda conserva el calor mejor que una hoja no modificada. El gasto energético de E. alba y U. bilobatum puede incrementarse hasta 55% y 48%, respectivamente, cuando la temperatura decrece entre 25°C y 20°C. Concluimos que como la temperatura en este sitio de estudio baja de los 25°C cada noche y hasta media mañana, utilizar una tienda que mantiene la temperatura arriba o cerca de los 25°C, provee una ventaja energética.

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

Localization of immunolabels by electron microscopy and image averaging

1983 ◽  
Vol 41 ◽  
pp. 282-283
Author(s):  
J. Frank ◽  
P.-Y. Sizaret ◽  
A. Verschoor ◽  
J. Lamy
Keyword(s):  
Electron Microscopy ◽  
Single Particle ◽  
Attachment Site ◽  
Uranyl Acetate ◽  
Limulus Polyphemus ◽  
Resolution Limit ◽  
Electron Microscopic ◽  
Image Averaging ◽  
Top View ◽  
Better Than

The accuracy with which the attachment site of immunolabels bound to macromolecules may be localized in electron microscopic images can be considerably improved by using single particle averaging. The example studied in this work showed that the accuracy may be better than the resolution limit imposed by negative staining (∽2nm).The structure used for this demonstration was a halfmolecule of Limulus polyphemus (LP) hemocyanin, consisting of 24 subunits grouped into four hexamers. The top view of this structure was previously studied by image averaging and correspondence analysis. It was found to vary according to the flip or flop position of the molecule, and to the stain imbalance between diagonally opposed hexamers (“rocking effect”). These findings have recently been incorporated into a model of the full 8 × 6 molecule.LP hemocyanin contains eight different polypeptides, and antibodies specific for one, LP II, were used. Uranyl acetate was used as stain. A total of 58 molecule images (29 unlabelled, 29 labelled with antl-LPII Fab) showing the top view were digitized in the microdensitometer with a sampling distance of 50μ corresponding to 6.25nm.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Electron Microscopic Observation of the Longitudinal Organization of Poly (p-Phenylene Terephthalamide) Fibers

1982 ◽  
Vol 40 ◽  
pp. 680-681
Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Microscopic Observation ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Aromatic Polyamides ◽  
Radial Arrangement ◽  
Scanning Electron ◽  
Better Than

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.

A High Angle, Double Tilting Cold Stage for the AEI EM7

1974 ◽  
Vol 32 ◽  
pp. 450-451
Author(s):  
P.R. Swann ◽  
A.E. Lloyd
Keyword(s):  
Habit Plane ◽  
Temperature Control ◽  
Tilt Angle ◽  
Cooling System ◽  
Thermal Drift ◽  
High Angle ◽  
Cold Stage ◽  
High Degree ◽  
Better Than

Figure 1 shows the design of a specimen stage used for the in situ observation of phase transformations in the temperature range between ambient and −160°C. The design has the following features a high degree of specimen stability during tilting linear tilt actuation about two orthogonal axes for accurate control of tilt angle read-out high angle tilt range for stereo work and habit plane determination simple, robust construction temperature control of better than ±0.5°C minimum thermal drift and transmission of vibration from the cooling system.

Thermal Considerations in Lens Regulator Systems

1970 ◽  
Vol 28 ◽  
pp. 358-359
Author(s):  
K.C. Newton
Keyword(s):  
Electron Microscope ◽  
Thermal Effects ◽  
Environmental Control ◽  
Reference Networks ◽  
Better Than

Thermal effects in lens regulator systems have become a major problem with the extension of electron microscope resolution capabilities below 5 Angstrom units. Larger columns with immersion lenses and increased accelerating potentials have made solutions more difficult by increasing the power being handled. Environmental control, component choice, and wiring design provide answers, however. Figure 1 indicates with broken lines where thermal problems develop in regulator systemsExtensive environmental control is required in the sampling and reference networks. In each case, stability better than I ppm/min. is required. Components with thermal coefficients satisfactory for these applications without environmental control are either not available or priced prohibitively.

Sign in / Sign up

Export Citation Format

Share Document