Material is arranged taxonomically in BugGuide, however in some cases it is useful or interesting to see material that belongs together for other reasons, ecologically, physiologically, etc. such as the members of an ecosystem.
Goldenrod galls are an example. About 50 species of gall makers have been reported (Zootaxa 2152: 1–35. 2009
) from goldenrods (Solidago
species). About two thirds of the gall makers are midges, family Cecidomyiidae
. More information on some goldenrod gall residents in Invertebrate Cold Hardiness
It is important to know the different species of goldenrod
as some gall makers are specialists while others attack a range of species (I confess my ignorance in this area). There are at least two genera which are called goldenrods, Solidago
In addition to the gall makers we should consider all the parasitoids, predators and inquilines. The total numbers must be quite substantial. In some cases more than fifty percent of galls are parasitized; furthermore, it seems that for each species of gall maker there are at least three or more different species of parasitoids, inquilines, etc. So, if you start studying goldenrod galls be prepared for many surprises. Probably the same could be said for other types of galls.
I will try to bring together all the goldenrod gall fauna that we have accumulated in BugGuide until now, September, 2009. Many IDs are tentative; corrections and suggestions are welcome. You can find additional information and links under the images shown here or on the respective information pages.
(The Solidago Eurosta Gall Homepage
). Let us start with the most familiar stem gall, easy to recognize, the round gall and its maker the tephritid fly or fruit fly Eurosta solidaginis
: galls of different sizes.
Round Gall Maker
: larva in its chamber, larva, puparium, emerging adult; adult ♀
and adult ♂
Apparently smaller galls are parasitized more often than larger ones; but the largest ones are eaten more often by chickadees and wood peckers.
Other Round Gall Residents
There are two species of parasitoid Eurytoma
wasps: E. gigantea
and E. obtusiventris
Larva; adult ♀
and adult ♂E. gigantea
; puparium induced prematurely by E. obtusiventris
Other parasitic wasps: Braconids, subfamily Doryctinae
An inquiline and predator of the goldenrod fly, the tumbling flower beetle, Mordellistena convicta
, larva and adult.
Gall Flies, Inquilines, and Goldenrods: A Model for Host-race Formation and Sympatric Speciation
Cornell Institute for Biology Teachers
. Goldenrod Gall Size as a Result of Natural Selection.
There are at least two types of elliptical stem galls and two different moth gall makers belonging to two different families. We have only one image of elliptical galls. We have no images of immature stages of the moths. We also lack images of the different parasitoids although a good number have been identified and although parasitized galls occur frequently. (The Goldenrod Elliptical-gall Moth Gnorimoschema gallaesolidaginis (Riley) and its Parasites in Ohio
Elliptical gall, Goldenrod Elliptical-Gall Moth
Parasitoid of Goldenrod Elliptical-Gall Moth
Goldenrod Gall Moth
Goldenrod bunch galls
or rosette galls have a very characteristic shape, with a cluster of leaves at the top of a stem. They can be very numerous in some fields. They are caused by a Cecidomyiid midge Rhopalomyia solidaginis
. This gall maker is considered an ecosystem engineer, a species that creates habitats for other species by providing food or shelter to them.
This gall and its inhabitants
1. Bunch gall, 2. Pupa, 3. Adult male
Gall with some inquilines, close up of inquiline beetle Microrhopala vittata (Goldenrod Leaf Miner)
, parasitic wasps, Platygaster sp.
, close up of wasp
Another Type of “Bunch” galls
The bunch maker is a moth. Bunch of leaves, close-up, unidentified caterpillar
A few leaves bunched together, in the tips of Euthamia graminifolia
. The maker is the midge Dasineura carbonaria
Stem borer moth
This may not be a gall, but it is close enough that I am including it here. It is also somewhat similar to the third type of “bunch galls”. It is made by the moth Dichomeris inserrata
Pupa inside stem, pupa, adult moth
They are smaller than all the other galls that we have seen so far, shaped like a long stemmed goblet and they can grow on leaves, stems or flowers. This goldenrod belongs to another genus, Euthamia graminifolia
, and it is sometimes called goldentop because the inflorescences are flat topped rather than arranged in a spike. The galls are caused by another Cecidomyiid midge Rhopalomyia pedicellata
Gall on leaf, close-up, midge pupa; gall on flower
Other Pedicellate Gall Residents
Clusters of 5 or 6 cocoons and pupae inside galls. Platygaster
, a parasitic wasp.
Pupa of unidentified parasitic wasp
Small galls, 3-7 mm, made by several twisted leaves and a blister made of two or three of such leaves.
A solitary gall, a cluster of galls, close-up of one gall
Blister Gall Maker
The gall maker is the midge Asphondylia solidaginis
Other Blister Gall Residents
These pupae are presumably parasitoids of the midge. There are at least two different species. IDs on this parasitoids are hard to obtain.
These adults emerged from the galls and may correspond to some of the pupae above. They are all parasitic Apocrita.
, probably two or more different species.
, at least two different species.
♀ ♂ ♂
, genus Blacus
Some larvae, probably a Hymenopteran parasitoid, awaiting identification
And the Eulophid Galeopsomyia
Solidago flower Galls
Other Gall Residents
Updated on 7/2/2010 to incorporate the Solidago
flower gall and its insects (Photos provided by MJHatfield)
Thanks to Charley Eiseman, Ross Hill and Dr. Netta Dorchin who have helped with identifications and references.