Hypocreales » Ophiocordycipitaceae » Ophiocordyceps

Ophiocordyceps blattae

Ophiocordyceps blattae (Petch) Petch, Trans. Br. mycol. Soc. 16(1): 74 (1931)

Index Fungorum number: IF 431869; Facesoffungi number: FoF 13966

Parasitic on cockroach nymphs (Blattaria). Sexual morph: Stromata 1.5–3 (x̄ = 2, n = 5) μm, up to 460 μm in wide, multiple, cylindrical, white, unbranched, fragile. Perithecia 120–300 × 100–200 (x̄ = 206 × 151, n = 15) μm, occurring on middle and upper portions of stroma, pale yellow, ovoid, partly immersed. Peridium 10–22 (x̄ = 15, n = 20) μm, composed of yellow cells of textura angularis. Asci 70–110 × 10–20 (x̄ = 91 × 13, n = 20) μm, fusiform, with round caps. Ascospores 45–60 × 2.5–4 (x̄ = 52 × 3.2, n = 20) μm, hyaline, fusiform, 7-sepate, with the secondary cells near to the both ends swollen into subglobose, whole when mature. Asexual morph: Hymenium covering the stromata, white, co-occurring with perithecia. Conidiophores 6.5–11 × 4.5–8 (x̄ = 8.5 × 5.5, n = 15) μm, laterally developing from superficial cells of stromata, subglose, smooth-walled. Phialides 10–25 × 6–9 (x̄ = 18 × 7.3, n = 20) μm, polyphialidic, hyaline, oblong to cylindrical, with numerous, cylindrical conidiogenous loci on the apex. Conidia 9–12 × 4.5–6.5 (x̄ = 11 × 5.3, n = 20) μm, hyaline, broadly fusiform, aseptate, slightly guttulate.

Material examined – Thailand, Chiang Mai Province, Chiang Dao District, on cockroach nymph lying on leaf litter, 12 August 2020, De-Ping Wei, CD0802 (MFLU 22-0268).

Notes – Ophiocordyceps blattae initially was introduced as a Cordyceps by Petch (1921) wherein the author illustrated this fungus. Petch (1931) established Ophiocordyceps and selected Cordyceps blattae as the type species. This species shows preference to cockroach nymphs and fastens its host to the underside of living leaves in the forest. It has been reported from Sri Lanka and Thailand (Araújo et al. 2021). In a survey of entomopathogenic fungi in Chiang Mai Province, Thailand, we found a cockroach parasite attached to a decaying leaf on the forest floor. Our specimen shares similarity with O. blattae in the stalked stromata, partly immersed perithecia, cylindrical asci with inconspicuous apical cap and elongated-fusiform whole ascospores. The phylogenetic analysis also confirms its close affinity with O. blattae.

 

 

Ophiocordyceps blattae (MFLU 22-0268). a, b Stroma growing from cockroach nymphs (Blattaria). c, d Stromata showing perithecia and conidiophores (indicated with white arrows). f Perithecium. g, h Asci. i, j Ascospores. k Conidiophores. l, m Phialides bearing conidium. n–q Conidia. Scale bar: b = 5 mm, c = 2 mm, d = 500 μm, e–h = 50 μm, i–k = 20 μm, l, m = 10 μm, n–q = 5 μm. (k was mounted in Congo red solution).

 

Reference:

Wei DP, Gentekaki E, Wanasinghe DN, Tang SM, Hyde KD. Diversity, molecular dating and ancestral characters state reconstruction of entomopathogenic fungi. Mycosphere. 13(2): 281–351.

 

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