Mastodawn

Colin Purrington Sep 7, 2025

Thread of the five types of galls I found yesterday. First up are oak rough bullet galls (Disholcaspis quercusmamma), protecting themselves from parasitic wasps by attracting ants with nectar. Swarthmore, PA, USA. 1/5 #GallWeek2025 #gall #galls #wasps #ants #oaks #cynipidae #inaturalist #nectar #nature #biology #quercus

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Colin Purrington

This is Andricus nigricens, another cynipid wasp that makes galls on oaks. Each lobe is home to a single larva (and possibly a parasite, because such is life). 2/5 #GallWeek2025 #gall #galls #wasps #oaks #cynipidae #inaturalist #quercus

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Colin Purrington Sep 7, 2025

This beautiful gall is made by the fungus, Rhytisma americanum. The common name is "American tar spot" to differentiate it from the other two members of the genus (in North America) that parasitize maples. The others are not nearly as pretty. 3/5 #GallWeek2025 #gall #galls #inaturalist #acer #maples #fungus #fungi

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Colin Purrington Sep 8, 2025

This gall is new to me so I hope I have identified it correctly. I think its a tupelo leaf edge gall (Aceria dina). If you squint you can see a mite walking on the upper right side of the upper fold, although I'm not sure if it is the eriophyid mite that makes the gall. 4/5 #GallWeek2025 #gall #galls #inaturalist #mites #arachnids #tupelo

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Colin Purrington Sep 8, 2025

Finally, here's another new-to-me gall that I've very, very tentatively ID'd as something made by Ophiomyia tiliae, a fly in the Agromyzidae. If I get a correction on iNaturalist I'll update this post. Possibly not even a gall! 5/5 #GallWeek2025 #gall #galls #inaturalist #mites #flies #diptera #tilia #basswood