Today’s letter H is for Heart. Do bees even have a heart? You may be surprised to learn that they sorta do, and sorta don’t. Like all insects, bees do not have a central circulatory system with a single heart pumping blood throughout the body. Instead, like most insects (really, most anthropods), bees have an open circulatory system that moves hemolymph throughout the body.

Bees and other anthropods have multiple “hearts” in a tubular heart structure throughout their body, as illustrated in the following image from misfitanimals.com. Humans and other mammals have a closed circulatory system with veins carrying oxygen and nutrients directly to muscles and organs throughout the body. In the open system of anthropods, the hemolymph floats within the body (openly) as shown by the arrows in the diagram.

The hemolymph is pumps by the hearts in the body as well as by general movement of the animal. These actions are dependent on acetylcholine receptors in the body that are activated by nicotine. This is one reason why neonicotinoids can be so deadly to insects. Such receptors in humans are less critical and thus these pesticides have a more limited impact on mammals. For a nice discussion of these effects, see this honey bee hearts discussion on the National Institues of Health website.

May you prosper and find honey.