Ferns are the second largest lineage of vascular plants, yet our understanding of their interactions with phytophagous insects is very limited. Which insects feed on ferns? Do insects prefer specific fern taxa? Which feeding habit is the most common on ferns? Is there any evidence for coevolution between insects and ferns? Is our current knowledge on fern-insect interactions biased? To answer these questions, we analyzed 2,318 records of fern-insect interactions from 122 literature sources, based on the feeding habit of insects, fern taxa, and geographic location. We found evidence for interactions comprising 809 insect species (mainly Hemiptera, Lepidoptera, and Coleoptera) and 382 fern species (mainly Dennstaedtiaceae, Dryopteridaceae, and Pteridaceae). Leaf chewers contributed over 50% of the species, followed by sap-sucking insects (29.1%) and spore feeders (6.5%). The overall interaction analyses revealed that the entire fern-insect network had medium levels of nestedness (NODF = 43.37) and relatively low levels of specialization (H2’ = 0.24). The interaction networks of fern-feeding Coleoptera were the most specialized at family (H2’ = 0.40) and genus level (H2’ = 0.65), whereas 6 out of 10 most specialized insect families were Lepidoptera (d’ ≥ 0.44). At the genus level, all networks had a fern-biased asymmetry. Although fern-feeding generalists were common, few cases of coevolutionary radiation have been documented. We discuss the possible biases of our dataset, which also highlight gaps to perform future research, and suggest that many more phytophagous insects on ferns remain to be discovered, especially sap-sucking, gall-forming, and spore-feeding insects on modern fern groups.

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Posted 19 Apr, 2021
On 29 Jun, 2021
Received 13 Apr, 2021
Invitations sent on 11 Apr, 2021
On 14 Mar, 2021
On 05 Mar, 2021
On 04 Mar, 2021
Posted 19 Apr, 2021
On 29 Jun, 2021
Received 13 Apr, 2021
Invitations sent on 11 Apr, 2021
On 14 Mar, 2021
On 05 Mar, 2021
On 04 Mar, 2021
Ferns are the second largest lineage of vascular plants, yet our understanding of their interactions with phytophagous insects is very limited. Which insects feed on ferns? Do insects prefer specific fern taxa? Which feeding habit is the most common on ferns? Is there any evidence for coevolution between insects and ferns? Is our current knowledge on fern-insect interactions biased? To answer these questions, we analyzed 2,318 records of fern-insect interactions from 122 literature sources, based on the feeding habit of insects, fern taxa, and geographic location. We found evidence for interactions comprising 809 insect species (mainly Hemiptera, Lepidoptera, and Coleoptera) and 382 fern species (mainly Dennstaedtiaceae, Dryopteridaceae, and Pteridaceae). Leaf chewers contributed over 50% of the species, followed by sap-sucking insects (29.1%) and spore feeders (6.5%). The overall interaction analyses revealed that the entire fern-insect network had medium levels of nestedness (NODF = 43.37) and relatively low levels of specialization (H2’ = 0.24). The interaction networks of fern-feeding Coleoptera were the most specialized at family (H2’ = 0.40) and genus level (H2’ = 0.65), whereas 6 out of 10 most specialized insect families were Lepidoptera (d’ ≥ 0.44). At the genus level, all networks had a fern-biased asymmetry. Although fern-feeding generalists were common, few cases of coevolutionary radiation have been documented. We discuss the possible biases of our dataset, which also highlight gaps to perform future research, and suggest that many more phytophagous insects on ferns remain to be discovered, especially sap-sucking, gall-forming, and spore-feeding insects on modern fern groups.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6
This is a list of supplementary files associated with this preprint. Click to download.
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