The Great Labor Day Mosquito Count

Livdahl Lab, Biology, Clark University

Tree Holes

Tree holes can be found in many different tree species . These entrances serve as prime breeding grounds for mosquitoes by providing a nesting habitat that collects both water and nutrients. Since mosquito eggs tend to hatch in low oxygen environments tree holes can facilitate this hatching by collecting rain water that runs down the tree, and then sustain this level since evaporation will take place much slower in the sheltered environment. In addition to being great areas for eggs to hatch in, treeholes also serve to accommodate the mosquito larvae once the eggs hatch. The mosquito larvae are suspension feeders and hang from the surface of the water filtering nutrients out which get trapped within the tree hole. The area also serves to protect the eggs and larvae from predators during development.

Note that most tree holes are found on the ground at the base of the tree, but it is also common to find them in the nook where two large branches of the tree merge at the base. It is also possible to find them farther up on the tree within a protruding knot.

Here are some examples of what common tree holes may look like when you encounter them in the wild.

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