Fungal Commensalists and Entomopathogens Flashcards
What are the three putative commensalist systems?
Labouls
Septobasidium
Fibulorhizoctonia
What are Laboulbeniales considered?
The fungal ticks of insects
What are the characteristics of Laboulbeniomycetes?
Determine growth
Lack an asexual state
Spores are sticky and attach to insect cuticles and send in a foot cell
Can be dioecious - male and female parts occur on different thalli
Spores are ejected by a trigger mechanism
Are Labouls harmful to their hosts?
Attachment is shallow; haustoria may or may not be formed
Infected insects tend not to live as long as uninfected; may be comorbidity factor with other fungal infections
Labouls are involved in which tripartite parasitism?
Bat - bat fly - laboul
What are septobasidium?
Scale insects live in pockets within the thalli and depend on the fungus for protection
The fungus has a network of tunnels connecting insect pockets
The parasitized insect individuals are immobile and sterile, and in a prolonged juvenile state
Sex differences within septobasidium?
Females are immobile and males can roam
When do the young in the septobasidium emerge?
In spring at the same time as basidiospores are formed, and disperse fungus elsewhere
What is a cuckoo fungus (fibularhizoctonia)?
A fungus that tricks termites into taking care of it
How does the cuckoo fungus trick the termite?
Not colour: termite balls and termite eggs are of a different color, but termites lack eyes anyway
Texture?
Chemical signals?
How does the cuckoo fungus use enzymes to trick termites?
They mimic termite eggs by producing the cellulose-digesting enzyme beta-glucosidase
What does the cuckoo fungus get out of the relationship?
Eggs and termite balls are groomed frequently; their saliva contains antibiotic substances that protect them from dryness and pathogens
The sclerotium is a tough ball of densely packed filaments that germinate into a fungal colony under favorable conditions
The relationship is facultative for the termites
No other fungi occur in the nest; no competitors
Is the cuckoo fungus pathogenic?
There are a small number of eggs in which the interior has been consumed and replaced by fungal hyphae
What does the termite get out of the relationship?
Under experimental conditions, the fungus improved survivorship of the eggs without native nest material
Fungal termite balls outnumber termite eggs in nests and yet are cared for, which costs energy
What are two parasitic fungal associations?
Cordyceps/Beauveria
Massospora
