Effect of fluid viscosity on the liquid-feeding flow phenomena of a female mosquito

Abstract

SUMMARYLiquid-sucking phenomena by the two-pump system of female mosquitoes were investigated to understand the feeding mechanism. In most previous experimental studies on liquid-feeding insects, the net increase of mass was divided by the feeding time and fluid density to evaluate the intake rate. However, this weighting method is not so precise for mosquitoes, because they are too lightweight to measure the gain of mass accurately. In this study, the intake rate of female mosquitoes feeding on various sucrose solutions was estimated using a micro-particle image velocimetry technique. As the sucrose concentration increased from 1% to 50%, the intake rate decreased from 17.3 to 5.8nls -1. In addition, the temporal volume variations of the two pump chambers were estimated based on the velocity and acceleration information of the flow at the center of the food canal of the proboscis. One pumping period was divided into four elementary phases, which are related to the different operational modes of the two pumps. According to the hypothetical model established in this study, the phase shift (α) between the two pump chambers increases from 14 to 28ms and the percentage of reverse flow to forward flow in a pumping period decreases from 7.6% to 1.7% with increasing viscosity. The developed analytical methodology thus aids in the study of an insect's feeding mechanism.

Experimental analysis of the liquid-feeding mechanism of the butterfly Pieris rapae

“…The intake flow rate Q can be estimated by the product of the feeding frequency f and the volume of the cibarial pump V cp , so Q≈V cp ×f (Lee et al, 2009). The feeding frequency is relatively constant based on the experimental results of Kim et al (Kim et al, 2013), so Q~V cp . Therefore, the relationship between the radius and the volume of the cibarial pump is derived as r 3~V cp , when the minimum power consumption for feeding occurs.…”

“…The butterflies were fed with artificial nectar using a cotton rod soaked in 10% sucrose. In this experiment, the butterflies were evaluated at 4 days post-emergence (Lee et al, 2009;Lee et al, 2014;Kim et al, 2011a;Kim et al, 2013).…”

“…The micro-PIV system comprises a vertical epi-fluorescence microscope (Eclipse 50i, Nikon, Tokyo, Japan), a continuous Nd:YAG laser (λ=532 nm, SLOC, Shanghai, China) as a light source, a high-speed CMOS camera (Photron ultima APX, Fujimi, Tokyo, Japan), and a personal computer for data processing and control (Lee et al, 2009;Lee et al, 2014;Kim et al, 2011a;Kim et al, 2013). Fluorescent particles (Molecular Probes, Eugene, OR, USA) with a mean diameter of ~1.0 μm were mixed with DI water (~2.5×10 9 beads ml −1…”

Comparison of the functional features of the pump organs of Anopheles sinensis and Aedes togoi

“…However, the mouthparts of blood-feeding arthropods have different morphological structures and functional mechanisms 5 . Mosquitoes regulate blood feeding by controlling the two pump organs the cibarial dilator pump (CP) and the pharyngeal dilator pump (PP) 7 . The valve-like organ (Vap) positioned between the two pumps appears to prevent backflow in the conduit connecting the two pumps (C-P) 7 .…”

“…Mosquitoes regulate blood feeding by controlling the two pump organs the cibarial dilator pump (CP) and the pharyngeal dilator pump (PP) 7 . The valve-like organ (Vap) positioned between the two pumps appears to prevent backflow in the conduit connecting the two pumps (C-P) 7 . The two pump organs assist in the feeding of liquid food and in the effective regulation of the blood-sucking process.…”