The conidiophores (Fig. 1) are erect, slender, hyaline, septate, unbranched, and 160-360 µm tall by 2.0-2.5 µm wide for most of their length and somewhat wider 3.5(4.0) µm at the base; conidiophores are scattered sparingly over the surface of captured animals and also develop from hyphae extending into the surrounding substrate. Conidiophores are not produced under water, and dead captured copepods must be exposed to air before conidiophores develop. Each conidiophore bears a solitary, terminal conidium at its apex. Conidia (Figs. 2, 6) are 56-97 µm long and 8.5-16 µm wide. They are very variable in size, shape, and number of septa. Septa vary from one to six, with most conidia having four septa. Conidia are more or less fusiform, broadest in the central region, and taper to a narrow connective at the attachment end and an acutely rounded apex at the distal end. In some conidia the apex of the conidium bifurcates about midway along its length to give a triradiate conidium. Frequently one of the central cells is markedly larger than the others. When conidia are transferred to copepod cultures they germinate overnight. In most cases conidia germinate from one or both ends to produce straight, unbranched, hyphal extensions. Sometimes the end cell dies and a hypha develops from the penultimate cell. After a short period of growth, usually less than the length of the conidium, the germ hypha enlarges, produces a series of several larger cells, and then terminates in a globose to subglobose adhesive BARI cell (Figs. 3, 7, 8). In this way a conidium gives rise to an adhesive cell at each end. Occasionally the germ hypha branches sparingly, and additional adhesive knobs are produced. The adhesive terminal cell attaches to the cuticle of a passing copepod, which moves around trailing the spore behind it (Figs. 9, 10). The cuticle of the copepod is penetrated, and the hyphae of the fungus colonize the interior. Infected copepods can be identified by their lack of ability to move normally and rapidly. They become moribund and succumb within 24 h, and hyphae then break out at a number of places through the cuticle to produce a proliferation of hyphae in the vicinity of the dead animal. A number of branches, with adhesive terminal cells, develop from the break-out hyphae. Branches are mostly 100-280 µm long. Some of these have the distinctive globose to subglobose adhesive terminal cell as described for the germinating spore. The adhesive cells are 7.2-8.0 µm wide and 7.2-10 µm long (Fig. 11). In other cases the branch produces an elongated, cylindrical, terminal portion 5.4-6.8 µm broad. This latter branch does not develop a swollen adhesive knob but apparently has an adhesive tip, as both types of branch can attach to larval or adult stages of the copepod. A proliferation of adhesive branches results in a number of captures at each site, and further growth takes place. Often, there is a weak zone in an adhesive branch, located in the narrow part of the hypha close to the point of origin (Fig. 5). The hypha is broken readily at the weakened section by a struggling copepod that then moves away with the branch attached to its body and disseminates the fungus.

HABITAT: Capturing and consuming larval and adult stages of copepods.

Conidiophora recta, subtilia, simplicia, 160-360 µm longa x 2.0-3.5 µm lata; conidia solitaria, phragmoseptata (1-) 4 (-6), hyalina, magna, fusiformia, 56-97 µm longa x 8.5-16 µm lata; rami tenaces ad 280 µm longi x 5.4-7.2 in latitudine maximo; cella globosa et tenax 7.2-10 µm longa x 7.2-8.0 µm lata.

No reproductive stages are produced under water. If a captured copepod breaks the surface, then conidiophores will grow up from the corpse. The easiest way to induce sporulation, therefore, is to drain excess liquid from the Petri dish. Within a day or two, conidiophores are found scattered sparingly over the surface of the colonized area.
In pure culture the fungus grows slowly on potato dextrose agar and malt extract agar. On these media the fungus is hyphal and very few conidia are produced. If a portion of such a colony is placed on water agar, however, it produces abundant conidia within a few days. Conidia produced in this way are more uniform in size and shape (Fig. 6) than those produced in association with the copepods. Such conidia are 90-104 µm long and 10.8-14.4 µm broad. Using Smith's rapid test for detecting cellulase production (Smith 1977), it was found that D. copepoddi was positive for cellulase.

TYPE: Slides and preserved material in Herbarium (OAC 10847); recovered from composted manure, Auckland, New Zealand, December 1988.