Oak Apple Galls

We’ve been finding new treasures around the Wild Woods. In an effort to discover what they are, I turned to Google and discovered they’re called Oak Apple Galls. It’s so fun to learn new things in the Wild Woods - I was blown away that something like this exists. It’s also been interesting to discuss the galls with the children and to hear their thoughts. If you’re interested in these cool galls, I included an excerpt from an online source below.

”“Oak apple galls” are leaves that have developed into a thin sphere because wasps have laid eggs inside of the leaf. Inside the gall is a tiny wasp larva. Most galls, especially on leaves, do not hurt the oak tree, and the wasps aren’t harmful to people either. In fact, like many insects, the wasps inside these galls are a beneficial source of food for our native wildlife, including many species of birds, as well as mammals such as opossums and raccoons. Galls have much to teach us about the complexity of the natural world around us, and demonstrate the importance of native tree species, such as oaks, for supporting biodiversity.

Oak apple wasps (Amphibolips confluent) are one of many insect species that rely only on oak trees, and have evolved a very specific method for living on oak trees. The entire life cycle of an oak apple gall wasp, spread over two years, happens on one single oak tree. The life cycle of the wasp begins underground, in the roots of the oak. Here, wasp larvae hatch and feed on roots of the oak tree. They develop into pupae, and then wingless adult females hatch from the pupae. In spring of the second year of the life cycle, the female adult wasps emerge from the ground and climb up the oak tree to the leaves. Then, they inject an egg into the veins of a newly growing leaf, and the gall begins to form.

As the egg hatches, chemicals and hormones released through fluid alter the leaf’s typical growth. Instead of developing into a typical leaf, the leaf develops these round balls to create the perfect tiny home for one wasp larva. The larva is in the center of the gall, and fibers extend from the center to the walls of the gall to keep the larvae safe and secure. When the larva reaches the right size, in June or July, it turns into a pupa, and then, finally, an adult wasp. The adult wasp exits the gall by making a hole, and the galls turn brown and sometimes drop to the ground. Males and females mate, and females burrow into the ground to lay eggs and begin the cycle again.”

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