Bootanomyia Girault, 1915

Ward, Anna K. G., Busbee, Robert W., Chen, Rachel A., Davis, Charles K., Driscoe, Amanda L., Egan, Scott P., Goldberg, Bailey A. R., Hood, Glen Ray, Jones, Dylan G., Kranz, Adam J., Meadely-Dunphy, Shannon A., Milks, Alyson K., Ott, James R., Prior, Kirsten M., Sheikh, Sofia I., Shzu, Shih-An, Weinersmith, Kelly L., Zhang, Linyi, Zhang, Y. Miles & Forbes, Andrew A., 2022, Borneosa aspera, Zoological Studies 61 (57), pp. 1-30 : 21-22

Bootanomyia Girault, 1915 ( Hymenoptera :

Chalchidoidea: Megastigmidae )

We reared 2,385 (mean = 596, range 1–2,307) wasps in genus Bootanomyia Girault from four gall types, all leaf galls on Quercus garryana on the Pacific coast. While several species from this genus are common parasites of oak galls wasps in the Palearctic (Doğanlar 2012; Askew et al. 2013), only one informal record exists of the genus in North America (photos #2020534-6 on BugGuide.org) and these are the first records we can find of Bootanomyia associated with oak gall wasps in the Nearctic. Though we did not key all of our collections to species, we keyed one to Bootanomyia dorsalis (Fabricius) using Doğanlar (2012). Molecular analysis of B. dorsalis in the western Palearctic found evidence for host-associated genetic differentiation among wasps reared from oak galls on trees in different oak subgenera ( Nicholls et al. 2018). Whether our collections represent an introduced population of B. dorsalis , another (or several) host-associated populations, or a combination of these two remains to be seen.

Ceraphronoidea ( Hymenoptera )

We reared 24 ceraphronoid wasps (mean = 8, range 2–11) from three different Belonocnema leaf galls. These were extremely uncommon, accounting for <0.15% of all associates reared from either gall type. The biology of most ceraphronoids is generally poorly known ( Johnson and Musetti 2004), but some have been reared from galls of cecidomyiid midges ( Loiácono and Margaría 2002).

Chalcididae ( Hymenoptera : Chalcidoidea)

We reared just two chalcidid wasps, one from each of two gall collections: Belonocnema fossoria and Neuroterus washingtonensis . Most Chalcididae are parasites of Lepidoptera or are sometimes hyperparasites of other Hymenoptera (though usually still in lepidopteran systems; Boucek and Halstead 1997). Our B. fossoria collections did have associated Lepidoptera . While we did not officially record lepidopterans from our N. washingtonensis collections, we observed larvae and moths emerging from these fleshy galls. Some chalcidids are known from Lepidoptera-induced galls (e.g., Prinsloo 1984), so these records may represent rare oviposition “mistakes.”

Crabronidae or Pemphredonidae ( Hymenoptera : Apoidea)

We r e a r e d t h r e e a p o i d w a s p s f r o m g a l l s of Andricus wheeleri Beutenmüller collected in Arizona and two more from galls of Disholcaspis quercusmamma collected in Minnesota. Some Apoid wasps create larval cells in hollow spaces associated with plants ( Ashmead 1894; Blommers 2008) and so these were likely occupying a gall emptied of its original inhabitants.

Encyrtidae ( Hymenoptera : Chalcidoidea)

We reared 22 encyrtid wasps (mean = 3.6, range 1–16) from six gall types. Encyrtidae are usually known as endoparasitoids and often are hyperparasitic on other hymenoptera ( Noyes et al. 1997). The rarity of these wasps among our collections leads us to believe that these were non-specific attacks on other gall associates.

Eumeninae ( Hymenoptera : Vespoidea: Vespidae )

We reared nine mason wasps (mean = 3, range 1–5) from three gall types. All three galls ( Disholcaspis quercusmamma , Andricus quercuscalifornicus , and Disholcaspis quercusglobulus ) were medium to large stem galls that are often retained on oak branches even after gall wasps and other insects have exited. While we did not identify the mason wasps in A. quercuscalifornicus , those in the two Disholcaspis galls were Bramble mason wasps ( Ancistrocerus adiabatus (de Saussure)) . Ancistrocerus adiabatus create larval cells of mud in existing cavities and provision cells with moth caterpillars. Bramble mason wasps are known to use abandoned homes of other insects, including galleries of cerambycid beetles, nests of other wasps, and empty galls ( Gosling 1978; Holm 2021). Joseph et al. (2011) previously recorded an unidentified species of vespid wasp in galls of Andricus quercuscalifornicus , and suggested it may be acting as a facultative predator.

Formicidae ( Hymenoptera : Formicoidea)

We found 70 ants (mean = 14, range 1–28) in association with five of our collections: Tapinoma Foerster in Amphibolips confluenta (Harris) galls, Camponotus Mayr (a queen), Temnothorax Mayr , and Tetramorium Mayr in Callirhytis quercuscornigera (Osten-Sacken) galls, Camponotus (workers and a queen), Temnothorax (workers and a queen), and Crematogaster Lund in Disholcaspis quercusmamma galls, Temnothorax on Andricus quercusstrobilanus (Osten-Sacken) , Brachymyrmex patagonicus Mayr and Crematogaster ashmeadi Mayr in Bassettia pallida Ashmead (previously reported in Weinersmith et al. 2020).

All ants recovered here are almost certainly colonists of older galls that had already been hollowed out by their original inhabitants. Previous studies have reported other ant species in other galls, e.g., Camponotus nearcticus Emery and Lasius alienus (Foerster) in galls of C. quercuscornigera ( Eliason and Potter 2000) , and seven different ant genera in galls of Disholcaspis cinerosa (Bassett) ( Wheeler and Longino 1988) . Besides living inside oak galls, some ant species are known to act as mutualists, feeding on honeydew produced by some gall types while actively defending those galls from parasites and predators ( Washburn 1984; Fernandes et al. 1999). We have observed ants tending Disholcaspis eldoradensis (Beutenmuller) galls (which produces honeydew) in the Pacific northwest (KMP, pers. obs.) and Crematogaster ants both living inside and tending galls of D. cinerosa in the southeastern U.S. (SPE, pers. obs.).

Platygastridae ( Hymenoptera : Platygastroidea)

We reared 913 platygastrids (mean = 91.3, range 1–867) from 10 gall types. The vast majority (867) of these were reared from Neuroterus washingtonensis galls on the Pacific coast but other sporadic collections came from Eastern galls. Weinersmith et al. (2020) previously reported three platygastrid genera ( Telenomus Haliday , Calotelea Westwood , and Synopeas Förster ) all from the same gall type. Platygastridae are usually egg parasites and Synopeas are known to parasitize cecidomyiid midges ( Abram et al. 2012). Midges were reared from six of these 10 gall types ( Table S1), such that these rearing records might not reflect direct associations with the gall wasp or its parasites.

Trichogrammatidae ( Hymenoptera : Chalcidoidea)

We reared 64 trichogrammatid wasps (mean = 21.3, range 1–62) from three gall types (62 from Neuroterus vesicula (Bassett) , one each from two other gall types). Trichogrammatidae are parasites of insect eggs ( Pinto 1997). A preliminary identification of these wasps keyed them to genus Poropoea Förster , known for parasitizing eggs of leaf-rolling weevils. It seems likely that these represent accidental collections of insect eggs and not formal gall associates.

Occasional associates – other insect orders and non-insect arthropods.

Coleoptera : We collected 413 adult or larval beetles (mean = 10.9, range 1–123) from 38 gall types. We did not identify all beetle collections beyond the level of order, but recognized Curculionidae , Ptinidae , and Staphylinidae among families represented. Many different beetles have previously been found in association with Nearctic galls, including Buprestidae , Cerambycidae , Cleridae , Curculionidae , Latridiidae , and Ptinidae ( Eliason and Potter 2000; Joseph et al. 2011; Forbes et al. 2016; Weinersmith et al. 2020). Of these beetle families, all besides Latridiidae are known to bore into galls (or at least into wood) or use galls as shelters ( Arnett and Thomas 2000; Sugiura and Yamazaki 2009). When the fates of insects reared from individual galls have been tracked, galls with beetle emergents produce no other insects (e.g., Hall 2001), suggesting that they effectively function as direct or indirect predators of all other gall associates.