Range and population observations on some of the more commonly reported cynipid galls in the Eastern US.

Was bored at work today waiting for a bioinformatic analysis to run, so decided to make some notes on the distribution of the more commonly reported oak gall wasps. Also included here are some remarks on the local populations of a few species that I have observed over several years.

Acraspis erinacei – generally more northern, present but less common in the south. In Ohio, one of the most common and most consistent year-to-year.
Acraspis quercushirta – Centered on Appalachians and East. Based on the map, looks to be most common on Q. montana, compared to its other hosts.
Acraspis macrocarpae – Northern distribution, also on Q. gambeli in the Rockies, has extended beyond the native range of its host to cultivated trees in Alberta, present in both Calgary and Edmonton as well as Missoula, Montana. Absent from the south.
Acraspis pezomachiodes – more northern as well. More compact distribution compared with A. erinacei, with which it is found often in Ohio. Very common in Ohio and consistent year-over-year populations.
Acraspis prinoides – interesting Midwest centered distribution, more reported on Q. muehlenbergii than Q. montana? Given the host specificity of Acraspis species and Andrew Hipp’s recent oak phylogeny, we should rear some of these to confirm they are the same species. Uncommon in Ohio, very rare to find a tree with more than a couple.
Amphibolips acuminata - Mid-Atlantic centered distribution, with scattered observations in the southern states. Commonly found on Q. imbricaria in swamps in NE Ohio.
Amphibolips citriformis – southern distribution consistent with the ranges of its hosts.
Amphibolips confluenta – widespread, eastern NA. Has exceeded natural range of host – credible observations in Lubbock TX and Albequerque NM on cultivated trees.
Amphibolips cookii – more common in the north, esp the NE. Very common in Ohio, rare to find a group of Q. rubra without one. Consistent population year-over-year.
Amphibolips gainesi - Texas-centered distribution. Its hosts are throughout the SE, so may be some sampling bias given the great gall hunters that we have in TX.
Amphibolips nublipennis – more common north and east. Not a common gall in NE Ohio, I have seen it most frequently on Q. imbricaria compared to its other hosts.
Amphibolips quercuscinerea – almost exclusively Florida. Supposedly hosted by Q. incana, which has a wider distribution, but is probably undersurveyed.
Amphibolips quercusinanis – widely distributed but not as far south as A. confluenta. Very common in Ohio and consistant year-over-year. In my area much more common than A. confluenta.
Amphibolips quercusjuglans – widely distributed in eastern NA, has exceeded natural range of hosts in at least one example – Abilene TX. Anecdotally, seems to have population fluctuations locally here in Ohio, a mega crop of these in some years and few and far between in others, related to mast years in their oak hosts?
Amphibolips quercusostensackenii – more common in north. Very common and consistent year-over-year in NE Ohio. On nearly every pin oak.
Amphibolips quercusracemaria – Southern coastal plain/piedmont. Especially along gulf coast. Hotspot in DFW.
Amphibolips quercusrugosa – Midwest/midatlantic-centered distribution, although might be some sampling bias bc this one is not particularly charismatic. In Ohio most common on Q. imbricaria on wetland sites.
Andricus aciculatus – Southern distribution. Were extremely common at one of the Q. lyrata sites that I visited in S. Illinois. Never observed on Q. stellata in Ohio.
Andricus biconicus – Scattered throughout eastern US on Q. stellata. Seems to be more common in Midwestern Q. stellata populations than southern ones, based on the relatively few reports from the DFW area. Very common on Ohio post oaks.
Andricus chinquapin – mid-Atlantic centered distribution, but very possible that there is sampling bias, given how subtle these are.
Andricus coronus – seems to be more common east of the Appalachians, scattered elsewhere. I have found at only one random site in NE Ohio, and have looked at 1000s of pin oaks.
Andricus dimorphus – Distribution centered on Midwest, somewhat mirrors the distribution of its most common host, Q. macrocarpa. Promiscuous, host-wise, and has consistent year-over-year populations.
Andricus ignotus – rare in SE, scattered elsewhere. Fairly common on bur oak in Ohio.
Andricus nigricens – Midwest-NE centered distribution. Extremely common on Q. bicolor in NE Ohio to the point of which I use it to ID the tree.
Andricus pattoni – more southerly distribution, but found wherever Q. stellata are. Very common on Q. stellata in Ohio.
Andricus quercusflocci – even distribution in E. NA. Seems to skew slightly more southern than other Q. alba galls given that is has only been observed once in Michigan, Minnesota or Ontario. Common in NE Ohio, though not as much as either of the Acraspis galls on Q. alba.
Andricus quercusfoliatus – Southern coastal plain and Texas.
Andricus quercusformosus – Eastern coastal plain-centered distribution. On my spring trip, this year was locally very common on Q.incana and Q. laevis in some Longleaf pine forests… seems to be rare elsewhere.
Andricus quercusfrondosus – Northern distribution (DFW hotspot). In Ohio, definitely more common on Q. macrocarpa than its other hosts and thus more common in the W. half of the state where that species is more concentrated.
Andricus quercuslanigera – Mostly southern coastal plain species, but has followed Q. virginiana wherever that species has been planted even to California.
Andricus quercuspeticola – widespread E. NA. Host promiscuous.
Andricus quercusstrobilanus – Midwest/midatlantic centered distribution, hot spot in Chicago (large bur oak concentration?). I have seen these by far most frequently on Q. macrocarpa compared to its other hosts.
Andricus quercusutriculus – Currently midwest/mid-atlantic centered distribution. But definitely suffers from sampling bias. Very subtle species.
Andricus weldi – Midwest/midatlantic. I suspect this is more common than reported bc it is somewhat subtle. Very common in NE. Ohio, esp on mature trees.
Atrusca quercuscentricola –An odd Missouri/Arkansas centered distribution – conspicuously rare from the very well reported DFW area. Has some color variation across the range, with the reds that are apparent in the Missouri/Arkansas populations not encountered as much farther east. Very common on Q. stellata in Ohio, esp at the darby plains sites.
Belonocnema kinseyi - Texas-centered distribution.
Belonocnema treatae – Florida-centered distribution.
Callirhytis clavula – more common north and east. Very common on Q. alba in NE Ohio, have not encountered elsewhere in Ohio.
Callirhytis favosa – Northern distribution, have noticed population dynamics in this species, common some years and rare in others.
Callirhytis furva – eastern US, in NE Ohio undergos extreme population fluctuations, anecdotally have noticed an every other year pattern, with this sometimes being the single most common gall and being much lower in alternate years – one of the most common galls in NE Ohio in summer 2020 and have only seen a couple times 2021.
Callirhytis gallaestriatae -- Seems to be northerly distributed but could be sampling bias given that these are extremely subtle. Fairly common in Ohio, very early in spring (before leaf out).
Callirhytis infuscata – interesting distribution mostly on a diagonal line from Toronto ON, to DFW, probably sampling bias. Not common in Ohio.
Callirhytis lanata – more common north and east. Very common in NE Ohio, hard to find a Q. rubra without one.
Callirhytis piperoides – northeast centered distribution. Not common in Ohio.
Callirhytis quercusbatatoides – S. Coastal plain and Texas.
Callirhytis quercuscornigera – Midwest/north Atlantic centered distribution. Probably most common on Q. imbricaria in NE Ohio, but fairly host-promiscuous.
Callirhytis quercusfutilis – Mid-atlantic centered distribution. Common in NE Ohio and most frequently seen on Q. alba and Q. bicolor.
Callirhytis quercusgemmaria – scattered E NA. Not common in NE Ohio, but subtle and so probably underreported.
Callirhytis quercusoperator – common on the east coast, scattered elsewhere (rare in NE Ohio).
Callirhytis quercusventricosa – Scattered distribution E NA. Very local populations in my experience. Anecdotally, seems to like less disturbed spots than many other species. Massive host list but I have only observed on Q. imbricaria in NE Ohio. Unlike other Q. imbricaria galls, I have found this one more frequenly on dry sites.
Callirhytis seminator – Widely distributed across E NA but more common East of the Appalachians (uncommon in NE Ohio). So showy as to be relatively over-reported.
Callirhytis vaccinii – Exclusively in Texas.
Disholcaspis cinerosa – Texas-centered distribution.
Disholcaspis globosa – More common Appalachians and east. Rare in Ohio.
Disholcaspis pruniformis – Texas-centered distribution.
Disholcaspis quercusglobulus – Wide distribution in Eastern NA. Very common and consistent populations year-over-year in NE Ohio.
Disholcaspis quercusmama – Somewhat northern distribution, where its two most frequent hosts (Q. macrocarpa and Q. bicolor) are more common.
Disholcaspis quercusvirens – E coastal plain and Texas, especially common in Florida.
Disholcaspis spongiosa – Southern distribution
Dryocosmus floridensis – Scattered distribution in E. US. Very common in NE Ohio on Q. imbricaria.
Dryocosmus quercuspalustris – more common north and east, but a hot spot in DFW as well. Extremely common in NE Ohio, and consistant year-over-year.
Kokkocynips decidua – NE centered distribution, Minnesota also a hot spot. Rare in Ohio (never personally observed).
Kokkocynips difficilis – Piedmont/coastal plain species. One of the few that looks to be more in the piedmont than the coastal plain, but could just be sampling bias.
Kokkocynips imbricariae – wide distribution E. NA, in NE Ohio most common on Q. rubra, but have seen on other host species as well.
Kokkocynips rileyi – more common in parts North and East, but a hot spot in DFW... might be some samping bias given that these are fairly tiny. In NE Ohio most common on Q. imbricaria and velutina, but have seen on most of the red oak group. Might have a couple of flushes in a year, seem to see fresh ones in June and again in late August/September.
Melikaiella tumifica – NE centered distribution. Present in Ohio, but not super common, easy to overlook
Neuroterus quercusirregularis - Seems like a trend to be more southern in distribution (but needs more sampling).
Neuroterus quercusbatatus – NE/Mid-Atlantic centered distribution. Scattered in NE. Ohio.
Neuroterus quercusvarrucarum – Scattered distribution in E. NA with hot spots (DFW, DC). Have noticed population fluxutions in this species, some years extremely common, some years rare in NE Ohio. On Ohio States main campus in Columbus was one of the single most common galls.
Neuroterus saltarius – Northern distribution, certainly more common than reported.
Neuroterus tantalus – Northern distribution, more common than reported. On nearly every Q. alba in NE Ohio.
Neuroterus umbilicatus – Midwest/mid-atlantic centered distribution, could be sampling bias as these are subtle. Easy to find, but not overly common in NE Ohio. Some year-to-year flux in populations.
Neuroterus vesicula – Midwest/mid-atlantic centered at the moment, but almost certainly subject to sampling bias.
Philonix nigra – more northern distribution. Some flux in populations, 2021 a low year in my experience.
Phylloteras nigrum – Midwest/midatlantic centered distribution, certainly some sampling bias here as they occur at a season (late September-October) when fewer people are looking. Not hard to find in NE Ohio, but not common either.
Phylloteras poculum – Midwest/mid-atlantic centered distribution. Common in NE Ohio but not as much as the Acraspis galls on Q. alba. Definitely more common on older trees in my experience.

Phylloteras vollutellae – Northern distribution, definitely more common in areas where host is common (Present in W. Ohio, have not found in NE Ohio). Seems to be very common in Chicagoland where Q. macrocarpa is king.
Trigonaspis polita – Disjunct peaks in population in Texas and Florida, scattered observations up the E coast.
Trigonaspis quercusforticorne – Far northern distribution. Chicagoland and Massachusetts the farthest south observations. Majority of observations in Canada.
Zopheroteras compressum – more northern distribution, although sampling bias definitely probable. Another late season gall.
Zapatella quercusphellos – NE/Mid-Atlantic centered distribution. Infrequent in NE Ohio, most common on Q imbricaria here.
Zopheroteras guttatum – more common North and East, with a hot spot in DFW, more common than reported (tiny size). Flucuates in population, in sync with C. furva.
Zopheroteras sphaerula – NE/midwest centered distribution, sampling bias a possibility as this is another tiny one.

Overall trends and questions
Many Q. alba galls (with the notable exception of DQG, A. quercusflocci and C. seminator) are more common in the north, Q alba rarer or more scattered in the South?
Several red oak galls are focused more north and east as well, again with a few notable exceptions. Does this just represent sampling error, is it a factor of tree density or something else?
Post oak galls tend to be southerly distributed, which makes perfect sense, but many are underreported in areas other than Texas… if you live in an area with post oaks go out and take a look. I think one of the problems here is that in areas other than TX/OK post oaks are not common in cultivation, and thus you need to go to rural areas to find them.
What drives population fluctuations in some species? Is it just simply that they emerge every other year? Do these fluctuations represent an adaptation to reduce parasitoid pressure?
How are some species able to expand their range beyond the range of their host while others stay quite local? Are some species more adaptable to wind distribution or hitching a ride on nursery plants?

Surveying of common but less charismatic species, particularly small bud galls and integral leaf galls.
Surveying of the less populated southern states - Northern Louisiana across through South Carolina.
Surveying of non-summer species - spring and fall species are less well surveyed.
Surveying of less common oak species that may be strong hosts for some of these "rare" species

Anyone with any thoughts on any of these species? Do your local populations match these observations or contradict them?

Αναρτήθηκε από calconey calconey, Σεπτέμβριος 16, 2021 0822 ΜΜ


Thank you for providing these extensive notes. I am not yet prepared to answer your questions but will bear them in mind.

Αναρτήθηκε από kimcwren περίπου 1 μήνας πριν (Αναφορά)

Here in Northern VA Calliryhtis furva is in a major boom cycle as compared to last year. Philonix nigra seems about the same this year as last. Andricus weldi is nearly absent here whereas last year they were everywhere. Time will tell though, as I think that the majority of these are high in mature trees and not seen until they start to fall later in the Fall.

I did not have a good source of Q stellata last year but I am seeing Atrusca carolina in numbers from one location that I found this year and it is hardly reported from anywhere else. Also Andricus robustus is abundant.

I am seeing a lot fewer Kokkocynips galls this year (I figured maybe they do not like their new names 😁).

For a super rare species, Andricus apiarum on Q alba seems to have a bumper crop here this year. All constrained to one area, but I have found at least a dozen whereas last year I found maybe 3 or 4 total.

I have yet to find a single instance of a leaf with > 1 Phylloteras poculum on it, they are scattered in singles, whereas last year I recall seeing leaves covered in them.

Like you Andricus nigrum is on every Q bicolor. I also see Andricus quercusstrobilanus on pretty much every Q bicolor.

Other than C furva as mentioned above, the most common gall I am seeing on various oaks in the Red Oak section is the "q-velutina-fuzzy-vein-globs". I seem to find at least one set of them on almost every Red Oak section oak I look at. Some trees have dozens of sets.

Neuroterus tantulus has got to be the single most abundant gall in my area. Every single Q alba has at least some scars on them and many have thousands (if not millions). This pic from backyard earlier in the year gives an idea: https://www.inaturalist.org/observations/80025680

I have to mention Zopheroteras cuneatum, it was great to find more this year and for someone else to find it in the DC area and then for @megachile to find it in Michigan was awesome. I think the challenge with these is how small (many < 0.5mm) and ephemeral (maybe 2 weeks from visible to gone) they are.

As for general trends, I have spent a lot of time IDing Oaks and Cynipids (Eastern NA) here on iNat over the past year and I have noticed that as a whole, the SE US seems under-sampled on iNat for these 2 categories. Even the large population centers like Atlanta, Charlotte, Birmingham, Nashville, etc. have surprisingly few observations as compared to the population sizes. Given the sheer diversity of oaks throughout the south I would definitely expect more gall observations from that region. While IDing Oaks I often see galls on the trees and through some spot checking I would say that it is not common that those galls are submitted as separate observations. So there is definitely under-reporting going on for galls because they are simply not recognized as distinct or something other than detritus.

Thanks for the post and prompting my stream-of-conscious rambling response.

Αναρτήθηκε από jeffdc περίπου 1 μήνας πριν (Αναφορά)

Agreed that undersampling in the southeast US is a huge gap. Just a few observers have revealed tons of new and undescribed species down there in their first year of really looking. Hopefully we can keep that momentum up and pick up some new observers around that area next year. There are also pockets of introduced galls that seem to be underobserved, perhaps because they occur on street trees naturalists might not typically spend much time on? Eg pachypsylla celtidisvesicula has one observation in Colorado. It's been interesting to see more bur oak galls from across Canada this year too--the great plains is even more underobserved and I think there are some new species to be found there.

The one major part of the literature I don't think any of us have spent any time with yet is Kinsey's books, and those focus heavily on range as a defining trait for subspecies and varieties. It will be interesting to look at those alongside some of these more fleshed out sets of observations and see if we can corroborate any of the patterns he identified. I think eg A q centricola is likely one of these cases.

In terms of observation bias, the year to year growth in iNat use probably swamps any potential year-to-year gall abundance effect so far.

A few of the species you mentioned I'm fairly suspicious our current IDs are overinclusive on and likely should be split or reassigned. C infuscata, Amphibolips in general, but specifically racemaria/nubilipennis, confluenta/quercusspongifica, juglans/fuliginosa/gainesi, cookii/tinctoriae. A ignotus and frondosus/stropus seem suspect to me as well.

In terms of annual fluctuations, I see a lot of old N quercusbatatus galls on white oak and one particular Q bicolor but no fresh ones this year. I checked for them a lot and saw no signs.

Αναρτήθηκε από megachile περίπου 1 μήνας πριν (Αναφορά)

Fantastic list. I'm not a gall person but appreciate this kind of effort and sharing.

Αναρτήθηκε από bkatzenberg περίπου 1 μήνας πριν (Αναφορά)

Q. alba does seem to be less widespread in the south. The only ones I ever seem to find were planted, which is unfortunate given the widespread gall diversity on this host. I'll have to make a trip north to look specifically for galls on this host.

Αναρτήθηκε από kemper περίπου 4 ώρες πριν (Αναφορά)

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