Let’s look for more spring oak galls this year!
Hi everyone!
Bisexual generation (sexgen) galls of most oak gall wasps are underobserved, so let’s keep our eye out for them this spring! The key is to look on the same trees you’ve seen lots of summer/fall galls, when new buds/leaves/flowers come out. If you’re interested, feel free to share this post or tag others in the comments.
@megachile posted this wonderfully detailed info on Forum (https://forum.inaturalist.org/t/spring-oak-gall-wasp-hunting/38630) so I highly recommend reading it to get ready.
I also wanted to share some examples of my own interest for our region, California.
Andricus kingi (Red Cone GW)
Common host: Quercus lobata (Valley Oak)
Red Cone galls are so common, yet there’s no observation of their sexgen galls to this day! This really blows my mind because I’ve seen some trees covered with thousands of Red Cones in summer. So I plan to revisit such trees this spring, and hope you can too. (The link above also has more tips how to look for these.)
Cynips douglasii (Spined Turban GW)
Common host: Quercus lobata (Valley Oak), Quercus douglasii (Blue Oak)
Another common galls in summer, but sexgen galls are still rarely observed. Here’s what they look like:
https://www.inaturalist.org/observations?place_id=any&taxon_id=469443&verifiable=any&field:Gall%20generation=bisexual
Andricus gigas (Saucer GW)
Common host: Quercus douglasii (Blue Oak)
Apparently there are many look-alike of this sexgen galls so we definitely need more observations. Again, look on the same trees where you’ve seen lots of Saucer galls in summer. For now, we don’t have much info other than this: https://www.gallformers.org/gall/1487
Andricus pattersonae (Plate GW)
Common host: Quercus douglasii (Blue Oak)
Similar to A. gigas, so look on the same trees where you’ve seen lots of Plate galls in summer. These tiny conical galls could also be sexgen galls of many other species but we don’t have enough data to compare at this moment:
https://www.gallformers.org/gall/1558
Cynips quercusechinus (Urchin GW)
Common host: Quercus douglasii (Blue Oak)
Another species with no sexgen gall observations, so who wants to be the first?
https://www.gallformers.org/gall/1725
Heteroecus pacificus (Beaked Spindle GW)
Common host: Quercus chrysolepis (Canyon Live Oak)
This one has a little more photo references so shouldn’t be hard to find, should it?
https://www.gallformers.org/gall/1961
https://www.inaturalist.org/observations?place_id=any&taxon_id=123507&verifiable=any&field:Gall%20generation=bisexual
https://joycegross.com/images.php?search=2&taxon=Heteroecus+pacificus&ordr=
Unknown Mini-Leaf GW
Common host: Quercus lobata (Valley Oak)
Last year, I found a tree with lots of “Mini-Leaf” galls (https://www.gallformers.org/gall/1944) in spring. Then in summer, I revisited the same tree and found lots of Rosette galls (Andricus wiltzae):
https://www.inaturalist.org/observations/119291719
It may be my wishful thinking that Mini-Leaf is the sexgen of Rosette (because they are both leafy green :)) but as you can read in the discussion above, I’m not confident with rearing adults so if anyone wants to try rearing adults from Mini-Leaf galls this spring, it’d be great!
This is just a tip of iceberg so if you know a spot with any particular galls abundant in summer, look for sexgen versions of them in this spring!
Noriko
