Cynipid gall-wasps and associated parasitoids
mushroomgall.jpg (57417 bytes)
This mushroom shaped gall is a Disholcaspis prehensa gall on a scrub oak. Like several other galls in this genus, it exudes sugary droplets from the top surface and is tended by ants. 
Clicking on the small pictures to the left should bring up a larger version of the photos.

One of my projects with Cynipid gall wasps involves the ant-tended galls made by Disholcaspis eldoradensis (second picture down).  In a collaboration with Anurag Agrawal, we showed that the tending Argentine ants decrease parasitism by a suite of 7 parasitoid species, and significantly alter the parasitoid community emerging from the galls and the response of the parasitoids to local gall density (Inouye & Agrawal 2004). In an on-going independent project I am comparing the effects of native ants and the invasive Argentine ant on the parasitoid community attacking these galls.

The leaf galls made by Andricus kingi are attacked by a different suite of parasitoid species than the woody Disholcaspis galls. I've found that A. kingi galls that happen to be close to D. eldoradensis galls being tended by ants (like the ones in the picture of D. eldoradensis) are also afforded some protection from parasitoids (Inouye in prep). I'm also looking for patterns of density dependent attack by the parasitoids of A. kingi, at scales of leaf (0 to ~50 galls/leaf), branch, and tree.

Using a common garden in California, I've found that different oak genotypes accumulate different cynipid gall communities. The gall communities are influenced by tree phenology, tree height, and foliar chemistry as well (Inouye, Hunter, & McBride in prep).

In addition to exploring the Cynipid galls on oak trees in California, I've also worked with Cynipid galls on oaks at high elevations in Costa Rica, on Gamble oaks in the Rocky Mountains, and I am starting to learn some of the species here in Florida. 

Dish eld with ants.JPG (87685 bytes)
The stem gall made by Disholcaspis eldoradensis on a Valley Oak (Quercus lobata), shown here with Argentine ants (Linepithema humile) tending the galls.
waspandgall.jpg (69899 bytes)
The leaf gall made by Andricus kingi on valley oaks (also seen above with D. eldoradensis). This is one about 5 parasitoid species that attack these galls, caught in this photo just after ovipositing in the gall.
fuzzylumpgall.jpg (90715 bytes)
Two kinds of leaf galls common on blue oaks in the Central coast range of California.
beakgall.jpg (51830 bytes)
The gall of Disholcaspis plumbella, the "beaked twig gall".
threadgall.jpg (62211 bytes)
This amazing gall belongs to a Dros pedicillatum, which induces these galls out on the ends of thin stalks on blue oak leaves..