Gall Week 2024

Hi Everyone!

With Gall Week quickly approaching this Saturday, I'd thought I would make a post highlighting some specific taxa that I am seeking to enhance my study on the diversity of the gall wasps in the tribe Diastrophini.

For a quick refresher, the Diastrophini are gall inducing and gall usurping wasps associated with the plant family Rosaceae. Diastrophini currently has 5 genera:

Diastrophus (19 species described)- gall inducers on brambles (Rubus) and cinquefoils (Potentilla, Drymocallis, Horkelia, Horkeliella[?], and possibly other closely related genera). Found in Nearctic, Palearctic, Neotropics

Xestophanes (3 species described)- gall inducers on Potentilla. Restricted to Palearctic.

Periclistus (18 species described)- gall usurpers of Diplolepis rose galls. Found in Nearctic and Palearctic.

Synophromorpha (4 species described)- gall usurpers of Diastrophus galls on Rubus. Found in Nearctic

Of these taxa my studies are primarily focused on uncovering the diversity of Diastrophus and Synophromorpha in the Nearctic and revealing how all these taxa are related through phylogenetics. Our lab here at Penn State is gearing up to do genome scale sequencing of these wasps, and we would love to receive specimens contributed from iNaturalist's rich community of explorers and enthusiasts.

This year I am especially interested in getting access to more galls and insects associated with cinquefoils from the Western US and Rubus from Southern US.

The Western US is a treasure cove for undiscovered biodiversity in the gall world. The bulk of Diastrophus's biodiversity is described from eastern US, and the western states have an even greater diversity of cinquefoils that could serve as potential hosts for these wasps. Of the described taxa I am particularly interested in figuring out the biology of Diastrophus fusiformans. This species was described in the 1890s from an unspecified species of cinquefoil, and I have yet to find/ rear wasps that match the type specimens perfectly. Many naturalists and I have fund undescribed galls on Potentilla, Horkelia, Drymocallis, and Horkeliella; and any of these hosts could be the host plant for D. fusiformans. These galls typically occur as swellings on the stem and petioles of their hosts but some even form cryptic galls that are hidden in the stem.

Horkelia is an endemic genus with its diversity concentrated in California and western Oregon. I have received/ reared specimens from 2 different Horkelia species that were distinct from each other morphologically and genetically. I would be elated to get even more samples from this genus, as I believe I have only scratched the surface of the species that utilize this host lineage.

Horkeliella is another genus of cinquefoil found in California. A couple years ago, Matt Purdy found these galls on Horkeliella congdonis (https://www.inaturalist.org/observations/130700577), and it is incredibly likely that these galls are caused by wasps in the genus Diastrophus.

Another diverse group of cinquefoils with Diastrophus galls is Drymocallis. So far I have found at least 5 different species of gallers associated with this genus. There is higher diversity of this genus in western US than in the east where there is predominantly one species, Drymocallis arguta. So far, each new host I have sequenced/ reared wasps from has been a different species.

In addition to these galls on cinquefoils, I would also love to get Rubus galls from southern regions North American. I am working on describing a new species of Synophromorpha reared from root galls on Rubus trivialis, which is one of the dominant species of Rubus in the southern US. I currently only have one specimen of the inquiline, and I would like to get more for a type series. I am also curious if there are other types of galls on this host besides the roots and would be interested in seeing if they are separate species from the root gallers. Synophromorpha kaulbarsi is described from a single specimen from Mexico, and its unknown what Diastrophus sp this wasp attacks or what host it is from, so any Rubus galls found in that region or further south in the US could help solve this puzzle.

If you find any galls that you would be willing to send, I can handle the rearing efforts on my end. If you could package the galls in a ziploc bag with airholes to prevent them from drying out and include the collection information on a note card alongside the galls in the ziploc as well that would be wonderful . The best package to put them in is probably a small box with some sort of padding inside or a padded envelope.

You can send them to the following address:

Charles Davis

112 Merkle Laboratory

Department of Entomology

Penn State University

University Park, PA, 16802

Let me know if you have any further questions and I am looking forward to seeing what galls we find in the coming weeks!

Posted on Σεπτέμβριος 03, 2024 0351 ΜΜ by