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Fern mirid - Felisacus elegantulus

By N A Martin (2015, revised 2017)

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Click to collapse Classification Info





Felisacus elegantulus (Reuter, 1904)

Click to collapse Common names Info

Fern mirid

Click to collapse Synonyms Info

Hyaloscytus elegantulus Reuter, 1904

Click to collapse Biostatus and distribution Info

This native mirid is widespread in the North Island, while it is found only in the Marlborough Sounds and Nelson in the South Island. It is also present in Australia. It occurs on its fern host plants in city gardens and parks as well as native ecosystems.

Conservation status: Widespread, not threatened.

Click to collapse Life stages and annual cycle Info

Adults and nymphs of this insect can be found at all times of the year in Auckland.

Adults tend to be found on host ferns that have sporangia (groups of spores) present. The female has a pointed end to her abdomen that houses the ovipositor, while the male genitalia are contained in a bulbous structure, called the genital capsule, at the end of the abdomen. The female uses her ovipositor to insert eggs into fern fronds.

Nymphs hatch from the eggs. There are five nymphal stages, each called an instar. Nymphs go from one stage to the next by moulting. During moulting, the skin on the dorsal side splits and the next stage pulls itself out of the old skin. First instar nymphs are like small, green, wingless adults. Later instars have red marks on their body, and the last two instars have wing buds. Nymphs have a pointed anal tube at the end of the abdomen that is particularly obvious in the later instars. Adults emerge from fifth instar nymphs.

Walking and flying

The nymphs and adults have three pairs of legs. The adults have two pairs of wings held over their body. The wings are transparent with dark veins.


Like other Hemiptera, the fern mirid has piercing and sucking mouth parts. The long stylets, special shaped rods, are held in the rostrum. When it wishes to feed, the bug moves the tip of the rostrum to a suitable part of the plant. The stylets are then gradually pushed into the plant. The stylets form two tubes, one through which saliva is injected into the plant and a second through which plants juices are sucked up into the insect. Feeding of the fern mirid has not been studied, but it probably can use its saliva to digest the tissues of the plant.

Click to collapse Recognition Info

The fern mirid is the only mirid that breeds on New Zealand ferns. The only other hemipterans (sucking bug) that breed on New Zealand ferns are aphids. The fern aphid, Idiopterus nephrelepidis Davis, 1909 (Hemiptera: Aphididae) is black. Two of the other aphid species are green and may be confused with the fern mirid, especially when they may occur on the same species of fern. The adult mirid looks quite different, being long and thin with wings held horizontally over the body, while aphids are more globular and the winged aphids hold their wings vertically above their body. The fern mirid nymphs are also quite different in appearance to fern aphids, the mirid being long and thin with antennae held out front while wingless aphids tend to be shorter and have two siphuncles at the back.

Click to collapse Natural enemies Info

There are no reports of natural enemies of the fern mirid, but it is likely that they are preyed on by birds, insect predators, and spiders.

Click to collapse Host plants Info

Host plants are native fern species from five families. Adults and juveniles feed by inserting their stylets into the plant. It is assumed that they inject saliva into plant cells and then suck out partly digested cell contents. They may also feed on unripe spores.

Table: Host plants of the Fern mirid, Felisacus elegantulus (Hemiptera: Miridae) from Plant-SyNZ database (24 July 2017). The reliability score shows the quality of evidence for the host association (1-10, 10=high).
Common Name(s)Scientific NameFamilyReliability IndexBiostatus
Shining spleenwort, Huruhuruwhenua, Parenako, Paretao, Pānako, Paranako, Paretao, Urūru whenuaAsplenium oblongifolium ColensoAspleniaceae10endemic
Sickle spleenwort, Petako, PeretaoAsplenium polyodon G.Forst.Aspleniaceae10indigenous, non-endemic
Rasp fern, PukupukuBlechnum parrisiae Christenh.Blechnaceae10indigenous, non-endemic
Japanese lady fernDeparia petersenii (Kunze) M.KatoDryopteridaceae9indigenous, non-endemic
 Diplazium australe (R.Br.) N.A.Wakef.Dryopteridaceae10indigenous, non-endemic
Water fern, Histiopteris, Mātā, MātātāHistiopteris incisa (Thunb.) J.Sm.Dennstaedtiaceae10indigenous, non-endemic
 Hypolepis ambigua (A.Rich.) Brownsey & ChinnockDennstaedtiaceae10endemic
Giant hypolepisHypolepis dicksonionioides (Endl.) Hook.Dennstaedtiaceae10indigenous, non-endemic
Hounds tongue, Hound's tongue fern, Strap fern, kōwaowao, pāraharaha, kōwaowao, Maratata, Pāraha, pāraharaha, RaumangaMicrosorum pustulatum (G.Forst.) Copel.Polypodiaceae10indigenous, non-endemic
Coastal brake, Netted brakePteris comans G.Forst.Pteridaceae10indigenous, non-endemic
Sweet fernPteris macilenta A. Rich.Pteridaceae10indigenous, non-endemic
 Pteris saxatilis (Carse) CarsePteridaceae10endemic
Shaking brake, Tender brake, Australian bracken, Tarawera, TuraweraPteris tremula R.Br.Pteridaceae10indigenous, non-endemic
Leather-leaf fern, PyrrosiaPyrrosia eleagnifolia (Bory) HovenkampPolypodiaceae10endemic

Click to collapse Control Info

Fern mirids may be found on ferns in gardens. Ferns are not known to exhibit feeding damage so control is not necessary.

Click to collapse Additional information Info

Mirid opportunists

Mirids are opportunists (Wheeler 2001) and it is possible that the fern mirid will prey on fern aphids and other small insects on ferns.

Click to collapse Information sources Info

Eyles AC, Schuh RT 2003. Revision of New Zealand Bryocorinae and Phylinae (Insecta: Hemiptera: Miridae). New Zealand Journal of Zoology 30: 263-325.

Lariviere M-C, Larochelle A 2004. Heteroptera (Insecta: Hemiptera): catalogue. Fauna of New Zealand 50: 1-326.

Plant-SyNZ: Invertebrate herbivore-host plant association database.

Wheeler AG 2001. Biology of the plant bugs (Hemiptera: Miridae): pests, predators, opportunists. New York, Cornell University Press. 506 p.

Click to collapse Acknowledgements Info

The New Zealand Plant & Food Research Institute Limited (Plant & Food Research) for permission to use photographs.

Click to collapse Update history Info

1 August 2017. NA Martin. Host plant table updated.

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