Winter might not seem like a good time of year to go checkout wildflowers. On the contrary, they can be just as much fun to observe and photograph in winter as in spring/summer. Winters lack of dense foliage can reveal things which are easy to overlook otherwise. Galls and Oothecas are two prime examples. the following photographs were taken along the Great Marsh trail in the Indiana Dunes National Park.
(Click on an image to view it full size.)
Galls
Galls are growths which appear on plants in response to an irritation, usually the result of an insect laying eggs inside a leaf or stem. You can think of it kinda like how our bodies produce scar tissue to cover up and protect a wound. Galls take many different forms, but in the winter there are several types which are easy to find.
Ball galls like this one are quite common in areas where goldenrod flourish. This particular gall is most likely associated with a fly called a Gall Fly. Inside is a single larvae which will emerge as a new fly in the spring by burrowing a small hole.Elliptical galls like this one house a moth larvae. The hole near the top of the gall is likely the result of the insect having matured and bored its way out. The protection provided by the hard outer surface of the gall is not complete however. Sometimes the hole is a sign that a bird drilled its way in and make a meal of the larvae. Seems like in nature just about everything is food for something else.This is a Bunch Gall. It is formed by a little midge, Rhopalomyia solidaginis. The presence of the midge stunts the growth of leaf stems, causing the leaves to curl in and form a tight ball.
Although Galls are typically formed as safe havens for certain insects, it is not uncommon for other insects and spiders to occupy them as winter homes.
Oothecas
Oothecas are the egg sacs’s of Praying Mantis’s. They appear similar to galls. But whereas galls are the result of plant growth around an irritant, Oothecas are created by secretions from the female mantis which harden around the stem of the plant. The Ootheca simply wraps partway around the stem, and you can easily remove it from the plant. But keep in mind that the papery ball can contain 100 or more mantis eggs/larvae.
This Ootheca has ruptured, releasing the juvenile mantis’s from within. It would be very cool to come across one while a hundred or so mantis’s come crawling out. Alas, some of the young mantis’s existence is brief as they quickly become a meal for one of their siblings. As I noted in another post, to a Praying Mantis everything in the world is either prey or another predator, including other mantis’s.The way that this Ootheca has been opened up makes me wonder if the Mantis’s inside became a meal for something else. Look closely and you can see what appear to be a column of grooves. I am guessing that these were where individual mantis eggs were located and where the larvae formed.This is a closeup of the grooves mentioned above. It was taken with a microscope at a magnification of about 50x.
I have heard stories of people bringing one of these papery balls home, where the warm temperature causes them to hatch. Suddenly you have a hundred or so little Praying Mantis’s running around the house.
