Related Experiment Video
Updated: Aug 1, 2025
12:09
Building an Enhanced Flight Mill for the Study of Tethered Insect Flight
Published on: March 10, 2021
3.0K
Haemolymph viscosity in hawkmoths and its implications for hovering flight
Artis Brasovs1, Alexandre V Palaoro1, Pavel Aprelev1
1Department of Materials Science and Engineering, Clemson University, Clemson, SC 29634, USA.
Proceedings. Biological Sciences
|May 1, 2023
Summary
Insect haemolymph viscosity, crucial for flight, varies non-monotonically with hawkmoth wing size. Optimal viscosity balances fuel delivery and circulation energy for efficient flight.
Area of Science:
- Insect physiology
- Biophysics
- Aerodynamics
Background:
- Hemolymph viscosity is a critical physiological parameter for flying insects.
- It impacts flight performance by affecting fuel delivery, nutrient circulation, and waste removal.
- Higher viscosity necessitates greater metabolic energy for hemolymph circulation.
Purpose of the Study:
- To investigate the relationship between hawkmoth wing size and hemolymph viscosity.
- To understand how hemolymph viscosity changes non-monotonically with wing size and wingbeat frequency.
- To explore the implications of viscosity modulation for flight energetics and the evolution of flight.
Main Methods:
- Magnetic rotational spectroscopy utilizing nickel nanorods was employed.
- Hemolymph viscosity was measured in resting hawkmoths (Sphingidae).
- Measurements were correlated with wing size and wingbeat frequencies.
Main Results:
- Hawkmoth hemolymph viscosity exhibits a non-monotonic dependence on wing size.
- Viscosity increases in small hawkmoths, peaks in mid-sized hawkmoths, and decreases in large hawkmoths.
- Hemolymph viscosity ranged from near-water levels in small/large moths to over twofold higher in mid-sized moths.
Conclusions:
- Circulatory strategies, including hemolymph viscosity, are modulated to meet metabolic demands of flight.
- Evolution of hovering flight requires precise viscosity adjustments to optimize fuel transport and minimize circulatory energy loss.
- Fine-tuning hemolymph viscosity is essential for balancing energy supply and circulation efficiency in flying insects.
Related Concept Videos
01:17Viscosity
5.9K
When water is poured into a glass, it falls freely and quickly, whereas if honey or maple syrup is poured over a pancake, it flows slowly and sticks to the surface of the container. This difference in the flow of different kinds of liquids arises due to the fluid friction between the liquid layers and the liquid and the surrounding material. This property of fluids is called fluid viscosity. In this example, water has a lower viscosity than honey and maple syrup.
The SI unit of viscosity is...
The SI unit of viscosity is...
5.9K
02:57Surface Tension, Capillary Action, and Viscosity
28.2K
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
28.2K
01:20Stokes' Law
1.4K
Viscous forces, like friction, are intermolecular forces that resist the relative motion of molecules over each other. When a solid body moves through a liquid, viscous forces drag it in the opposite direction. The force's magnitude depends on the solid's shape and size, as well as its speed and the liquid's coefficient of viscosity, density and temperature.
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only...
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only...
1.4K
01:19Viscosity of Fluid
500
Viscosity measures the resistance a fluid offers to flow and deformation. It results from internal friction between layers of fluid moving relative to one another. Dynamic viscosity, denoted by the Greek letter mu (μ), quantifies the force needed to move one fluid layer over another. For Newtonian fluids like water and air, the relationship between the shearing stress and the rate of shearing strain is linear, meaning their viscosity remains constant regardless of the applied stress.
500
01:47Osmoregulation in Insects
16.6K
Malpighian tubules are specialized structures found in the digestive systems of many arthropods, including most insects, that handle excretion and osmoregulation. The tubules are typically arranged in pairs and have a convoluted structure that increases their surface area.
16.6K
01:07Cohesion
54.5K
Cohesion is the attraction between molecules of the same type, such as water molecules. Water molecules have an overall neutral charge but are polar molecule. An oxygen atom in one water molecule has a partial negative charge that can bind to a hydrogen atom with a partial positive charge in a second water molecule, forming a hydrogen bond. Each water molecule can form up to four hydrogen bonds with other water molecules. Hydrogen bonds are responsible for water's cohesive nature.
On a...
On a...
54.5K