3.3. Allometric relationships of the suction pump
In P. rostrata, both cibarial and pharyngeal pump muscles displayed a significant positive relationship with proboscis length. Regarding the cibarial pump, the main dilator and both suspension muscles showed a significant positive relationship with increasing proboscis length (Fig. 6A). Furthermore, volumes of the pharyngeal dilator and compressor muscles significantly increased with proboscis length (Fig. 6B).