Introduction to Fungi, Third Edition

676 ANAMORPHIC FUNGI
Fig 25.2 Scanning electron micrograph of the adhesive net of
Arthrobotrys oligospora, showing the glue covering the hyphal
surface. Reproduced from Nordbring-Hertz (1972) by
copyright permission of Physiologia Plantarum.Original
photograph kindly provided by B. Nordbring-Hertz.
Fig 25.1 Gamsylella sp.Hyphae showing short lateral branches
modified as sticky knob traps, with nematodes attached at
several points.This species would be called Monacrosporium sp.
in traditional nomenclature because of the single conidium
produced at the end of the conidiophore.
producing traps of this kind in the genus
Arthrobotrys. Adhesive nets are illustrated for
A eudermata (syn. Monacrosporium eudermatum,
Duddingtonia flagrans) in Fig. 25.3 and for
A. robusta (Fig. 25.4). Arthrobotrys oligospora
(Fig. 25.2) is by far the most thoroughly investigated
member of the genus.
Non-constricting rings. A number of predatory
fungi ensnare their prey by three-celled
rings which are formed by recurvature of the tip
of a lateral branch, followed by its anastomosis
with itself. Non-constricting rings have a sticky
inner surface. A nematode thrusting its body
into such a loop may become tightly wedged
inside it, and may find it impossible to
retract. The point of junction of the loop to
the subtending hypha is often weak, and the
struggling nematode may detach the loop.
Occasionally, a single nematode bearing several
loops may be seen. The detached loops are still
capable of penetrating and killing the nematode.
The action of this trap is passive, i.e. there is
no inflation of the ring. Fungi producing
non-constricting rings also form stalked
adhesive knobs and are included in
Dactylellina (Scholler et al., 1999). An example is
D. haptotyla (syn. Dactylaria candida), shown in
Fig. 25.5.
Constricting rings. The most dramatic type of
trap is the constricting ring trap, which develops