91
authors conclude that the fungus was parasitic based on the presence of conidia budding along with smaller secondary conidia adjacent to the main mycelial mat, a
characteristic of modern Entomophthorales (Prasertphon 1963). In addition, a fossil
member of the Laboulbeniales, which are obligate ectoparasites, has been discovered on the thorax of a fossil stalk-eyed fly (Prosphyracephala succini) in Eocene
Baltic amber (Rossi et al. 2005). An enigmatic fossil from Myanmar amber,
Spheciophila adercia, also attributed to the Laboulbeniales, consists of a thallus
with numerous perithecia and antheridia that is attached to the abdominal tergite of
a primitive wasp (Poinar 2016b). This author suggests that S. adercia belongs to an
extinct lineage because there are no other extant thallus-forming ectoparasitic fungi.
Finally, an example of a special form of fungal parasitism, predation (carnivory),
has also been fossilized in amber (Schmidt et al. 2007). Several specimens of a
fungus that used hyphal rings as trapping devices occur in Late Cretaceous amber
from France together with the fungus’ prey, small nematodes. The fossil nematodetrapping fungus cannot be assigned to any recent taxon of carnivorous fungi, but
rather suggests that different groups occupied this ecological niche in the Cretaceous
and that trapping devices evolved independently multiple times in the course of
Earth history. Predatory fungi catch microorganisms using a remarkable array of
trapping devices; however, their primary ecosystem function appears to be that of
wood decay, and hence they are saprotrophs that attack other organisms as sources
of nitrogen to supplement a primarily carbohydrate (woody) diet (Barron 2003).
3.3.4.3 Cordycipitaceae Interactions with Arthropods
Fungi in the family Cordycipitaceae (Ascomycota) enter into several types of fascinating parasitic interrelationships with insects and other arthropods that usually, but
not always, result in the death of the arthropod host (Sung et al. 2007). For example,
Ophiocordyceps unilateralis enters ants and eventually takes control over the host’s
brain activities (commonly named ‘zombie’ infection) and manipulates its behavior.
The manipulated ant, which becomes a so-called parasite-extended phenotype
(Hughes 2014), is forced by the fungus to move to so-called death locations (usually
plant parts) that represent ideal spots for fungal spore dispersal (de Bekker et al.
2014, 2015; Shang et al. 2015). Arrived at its death location, the fungus forces the
ant to bite into the substrate (e.g., a leaf or small plant axis) and remain in that position until death arrives. These bites leave a characteristic scar in the plant known as
the ‘death-grip’ (Anderson et al. 2009). Although it is exceedingly rare to capture
multiple stages of fungal life histories in the fossil record, there are three documented examples of fossils displaying stages of the Cordycipitaceae life cycle. One
includes an ant preserved in Dominican amber that is covered in a fungus morphologically similar to certain present-day species in Beauveria (Cordycipitaceae),
which are obligate endoparasites (Poinar and Thomas 1984). The sexual stages (or
teleomorphs) of Beauveria, where known, are species of Cordyceps (Rehner et al.
2011). The second example is a spectacular specimen of a fungus formally described
as Paleoophiocordyceps coccophagus, which is a parasite of Cretaceous scale
3 Fungi as Parasites: A Conspectus of the Fossil Record
authors conclude that the fungus was parasitic based on the presence of conidia budding along with smaller secondary conidia adjacent to the main mycelial mat, a
characteristic of modern Entomophthorales (Prasertphon 1963). In addition, a fossil
member of the Laboulbeniales, which are obligate ectoparasites, has been discovered on the thorax of a fossil stalk-eyed fly (Prosphyracephala succini) in Eocene
Baltic amber (Rossi et al. 2005). An enigmatic fossil from Myanmar amber,
Spheciophila adercia, also attributed to the Laboulbeniales, consists of a thallus
with numerous perithecia and antheridia that is attached to the abdominal tergite of
a primitive wasp (Poinar 2016b). This author suggests that S. adercia belongs to an
extinct lineage because there are no other extant thallus-forming ectoparasitic fungi.
Finally, an example of a special form of fungal parasitism, predation (carnivory),
has also been fossilized in amber (Schmidt et al. 2007). Several specimens of a
fungus that used hyphal rings as trapping devices occur in Late Cretaceous amber
from France together with the fungus’ prey, small nematodes. The fossil nematodetrapping fungus cannot be assigned to any recent taxon of carnivorous fungi, but
rather suggests that different groups occupied this ecological niche in the Cretaceous
and that trapping devices evolved independently multiple times in the course of
Earth history. Predatory fungi catch microorganisms using a remarkable array of
trapping devices; however, their primary ecosystem function appears to be that of
wood decay, and hence they are saprotrophs that attack other organisms as sources
of nitrogen to supplement a primarily carbohydrate (woody) diet (Barron 2003).
3.3.4.3 Cordycipitaceae Interactions with Arthropods
Fungi in the family Cordycipitaceae (Ascomycota) enter into several types of fascinating parasitic interrelationships with insects and other arthropods that usually, but
not always, result in the death of the arthropod host (Sung et al. 2007). For example,
Ophiocordyceps unilateralis enters ants and eventually takes control over the host’s
brain activities (commonly named ‘zombie’ infection) and manipulates its behavior.
The manipulated ant, which becomes a so-called parasite-extended phenotype
(Hughes 2014), is forced by the fungus to move to so-called death locations (usually
plant parts) that represent ideal spots for fungal spore dispersal (de Bekker et al.
2014, 2015; Shang et al. 2015). Arrived at its death location, the fungus forces the
ant to bite into the substrate (e.g., a leaf or small plant axis) and remain in that position until death arrives. These bites leave a characteristic scar in the plant known as
the ‘death-grip’ (Anderson et al. 2009). Although it is exceedingly rare to capture
multiple stages of fungal life histories in the fossil record, there are three documented examples of fossils displaying stages of the Cordycipitaceae life cycle. One
includes an ant preserved in Dominican amber that is covered in a fungus morphologically similar to certain present-day species in Beauveria (Cordycipitaceae),
which are obligate endoparasites (Poinar and Thomas 1984). The sexual stages (or
teleomorphs) of Beauveria, where known, are species of Cordyceps (Rehner et al.
2011). The second example is a spectacular specimen of a fungus formally described
as Paleoophiocordyceps coccophagus, which is a parasite of Cretaceous scale
3 Fungi as Parasites: A Conspectus of the Fossil Record