Hemolymph circulation in insect flight appendages: physiology of the wing heart and circulatory flow in the wings of the mosquito,Anopheles gambiae

Abstract

The wings of insects are composed of membranes supported by interconnected veins. Within these veins are epithelial cells, nerves and tracheae, and their maintenance requires the flow of hemolymph. For this purpose, insects employ accessory pulsatile organs (auxiliary hearts) that circulate hemolymph throughout the wings. Here, we used correlative approaches to determine the functional mechanics of hemolymph circulation in the wings of the malaria mosquito Anopheles gambiae. Examination of sectioned tissues and intravital videos showed that the wing heart is located underneath the scutellum and is separate from the dorsal vessel. It is composed of a single pulsatile diaphragm (indicating that it is unpaired) that contracts at 3 Hz and circulates hemolymph throughout both wings. The wing heart contracts significantly faster than the dorsal vessel, and there is no correlation between the contractions of these two pulsatile organs. The wing heart functions by aspirating hemolymph out of the posterior wing veins, which forces hemolymph into the wings via anterior veins. By tracking the movement of fluorescent microspheres, we show that the flow diameter of the wing circulatory circuit is less than 1 µm, and we present a spatial map detailing the flow of hemolymph across all the wing veins, including the costa, sub-costa, ambient costa, radius, media, cubitus anterior, anal vein and crossveins. We also quantified the movement of hemolymph within the radius and within the ambient costa, and show that hemolymph velocity and maximum acceleration are higher when hemolymph is exiting the wing.

Physical and behavioral adaptations to prevent overheating of the living wings of butterflies

“…The functional morphology of wings has been described in a number of insect orders [43][44][45][46] , but the relationship between the circulatory and tracheal systems in wings has only been explored in detail for a few groups 11 . In V. cardui, we observed that wing veins provide pathways for the tidal flow of air and hemolymph ( Fig.…”

Structural and functional characterization of the contractile aorta and associated hemocytes of the mosquito Anopheles gambiae

“…The circulation of hemolymph in areas that are distant from the dorsal vessel is aided by accessory pulsatile organs. These auxiliary hearts are located at the base of the antennae, in the scutellum, and in the ventral abdomen (Clements, 1956;Andereck et al, 2010;Boppana and Hillyer, 2014;Chintapalli and Hillyer, 2016).…”

Classification and Selection of Cellular Materials in Mechanical Design: Engineering and Biomimetic Approaches

“…In-plane gravity loads, seasonal variation in weight [54,61] Toughness under compressive and impact loading [7] Flexural rigidity [62], fracture toughness [63] Biological Storage of brood, pollen and nectar; minimization of material (effort) [61] Storage for bone marrow, nerves and blood vessels [64] Circulation of hemolymph through wing [65] Radiolarian shell Aulonia hexagona…”