Fig. 3.

Larval and adult hemolymph flow velocity. (A) Diagrammatic representation (dorsal view; anterior on top) of intracardiac hemolymph flow in larvae (left) and the adult abdomen (middle and right). Hemolymph inside the larval heart is only propelled in the anterograde direction (AG; red arrow) whereas hemolymph is propelled across the adult heart in both anterograde (red arrow) and retrograde (RG; blue arrow) directions. (B) Diagrammatic representation (ventral view) of extracardiac hemolymph flow in the larval ventral abdomen, showing that hemolymph only moves in the retrograde direction (blue arrows). (C) Hemolymph velocity in the heart of larvae and adults, as determined by the tracking of neutral density fluorescent microspheres. Intracardiac (anterograde) hemolymph in larvae travels significantly more slowly than intracardiac (anterograde and retrograde) hemolymph in adults. (D) Extracardiac retrograde hemolymph flow in the ventral abdomen of larvae. In larvae, extracardiac flow is significantly slower than intracardiac flow. For box plots, the center line marks the median, the box marks 50% of the data, and the whiskers mark 90% of the data.