A synopsis of fern galls in Brazil

Abstract

Galls are neo-formed plant structures induced by species-specific interaction between an inducing organism and a host plant. Lycophytes and ferns are two distinct plant lineages historically lumped together as pteridophytes. A number of authors suggest low gall frequency in lycophytes and ferns, compared to angiosperms. This study aimed at compiling an updated overview of fern galls in Brazil, providing information on hosts, gall-inducing organisms and associated fauna. The synopsis was compiled using existent data and by updating scientific names and gathering new information obtained by the authors in fieldwork. To date, galls have been recorded on 16 fern species but none on lycophytes. However, the inducer was identified at species level in only three gall morphotypes from three fern species, with a doubtful inducer for Pteridium sp. Galls are induced by mites (Eriophyidae) and insects of the orders Diptera, Lepidoptera, Thysanoptera, and Hemiptera, Cecidomyiidae (Diptera) being the most frequent galler insect. Keywords: Pteridophytes, lycophytes, galls, Neotropical, Cecidomyiidae. Sinopse de galhas em samambaias no BrasilResumo: Galhas são estruturas vegetais neoformadas induzidas por interações espécie-específicas entre um organismo indutor e uma planta hospedeira. Licófitas e samambaias são duas linhagens de plantas historicamente classificadas juntas como pteridófitas. Diversos autores sugerem que há uma baixa frequência de galhas em licófitas e samambaias, em comparação com as angiospermas. Este trabalho tem como objetivo fornecer um panorama atualizado sobre as galhas em samambaias no Brasil, disponibilizando informações sobre espécies hospedeiras, galhadores e fauna associada. A sinopse foi realizada compilando-se os dados existentes, atualizando os nomes científicos e agregando informações novas obtidas pelos autores em trabalhos de campo. Até o momento, foram registradas galhas em 16 espécies de samambaias e nenhum registro em licófitas. Contudo, em apenas três morfotipos de galhas, de três espécies de samambaias, o indutor foi identificado a nível de espécie, com um indutor duvidoso para Pteridium sp. As galhas são induzidas por ácaros (Eriophyidae) e insetos das ordens: Diptera, Lepidoptera, Thysanoptera, Hemiptera, sendo Cecidomyiidae (Diptera) o galhador mais frequente.

Galls on Brazilian ferns: new records and notes

“…Interestingly, in H. pulchellum, the galls are close to tuffs of leaves ( Figure 4C-E), which may be a source of nutrients to galling or only an error in the manipulation of plant systems. In Gleicheniaceae, galls induce a complete modification of leaf shape, the "witches' broom" (Table 1), already described by Santos and Maia (2018) on D. flexuosa ( Figure 1C-E) in Rio de Janeiro reported for angiosperms (e.g. Maia and Oliveira, 2010).…”

“…In consequence, basic information such as the identity of gall host ferns, the frequency and locations of the interaction are still poorly known. Until present, only 16 fern species have been recorded as galls hosts in Brazil (see synopsis in Santos and Maia, 2018). In this note, we catalog ten ferns hosting galling agents, including four new records of galls, and report new locations to some ferns recorded as hosts, and characterize the morphology of the galls.…”

“…Houard (1933) reports Diptera species as gallers of H. hirsutum and H. pulchellum. Santos and Maia (2018) suggested mites as inducers of the "witches' broom" galls on D. flexuosa, an assumption extended to D. nervosa and D. rufinervis. Efforts must be directed to identify all these organisms.…”

“…The other two records to Hymenophyllum fill the gap on the geographic distribution, not recorded in the seminal work performed byHouard (1933). The records of N. crassifolium (Figure 5A, B), C. nitidum(Figure 5C, D)and P. hirsutissima (Figure 5E, F)presented here were first obtained from tropical rain forests of Rio de Janeiro State(Santos and Maia, 2018), representing new locations to these gall host ferns. The galls observed in H. pulchellum (Figure 4C-F)and H. hirsutum (Figure 3A-F)were recorded in two locations in the South and Southeast region of São Paulo and Rio Grande do Sul States…”

Occurrence of galls in Microgramma mortoniana (Polypodiopsida: Polypodiaceae) from a subtropical forest, Brazil

“…Hanson & Gómez-Laurito (2005) recorded galling insects associated to 17 fern species only for the Costa Rica. Considering the Brazilian region, Santos & Maia (2018) reported galls for 16 fern species, including the first record of galls for the Cyatheaceae family, made by Farias et al (2018) for Cyathea phalerata Mart. in the northeastern region of Brazil.…”