Hedgehog Gall Wasp (Acraspis erinacei)

Gall wasps are very interesting insects as they seem to have formed an odd way of reproducing. Additionally, their egg sacs, or "galls", are also fascinating to look at and study. So let's look at them and find out why they are so special.


Physical Description and Behavior


These wasps are generally black but can have a yellowish or brownish appearance. They are humpbacked with 2 segmented abdomens, with their hindquarters being larger than the chest and head combined. Their wings are transparent and you do not have to worry about them stinging you as they have no stinger.


Fun fact: Hedgehog gall wasps breed in generations. When a female mates and lays her eggs, the first generation is completed. This first generation consists only of females, who then later lay eggs of their own asexually. This second generation of eggs will then hatch into both male and female wasps, and then the whole loop starts all over again.


One of the most fascinating things about the gall wasp is its reproduction. During the sexual generation, they will insert their eggs inside the leaves of the white oak (their host tree that they are dependant on for their survival), which causes the leaf to break out, forming galls on the stems. During the asexual generation, the galls swell in size, forming what looks like a sickly yellow pustule covered in red hairs.


These galls are about 13mm in diameter (about the size of a dime) and contain about 3-5 larval cells. It is unclear why their reproduction is like this, or how it benefits them in the long term.


Habitat and Location


This wasp is generally found in central and eastern United States, such as in Indiana, Michigan, Illinois, and even as far south as Texas. They also can be seen in the lower portions of Quebec and Ontario as well.


If you want to know more about this and other species of gall wasp, check out the information in the video below:


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