Amblyosporidae

The Amblyosporidae are a family of microsporidian fungi from the order Amblyosporida.^[1] They are obligate intracellular parasites known for infecting insects, particularly mosquitoes, and crustaceans such as copepods, with complex life cycles involving multiple hosts and transmission strategies.

Amblyosporidae
Scientific classification
Kingdom:	Fungi
Division:	Microsporidia
Class:	Microsporea
Order:	Amblyosporida
Family:	Amblyosporidae Weiser, 1977

Description

Amblyosporidae are microsporidia, a group of unicellular, spore-forming fungi classified within the Rozellomycota.^[1] They are characterized by their polymorphic development, producing morphologically distinct spores adapted for different hosts and transmission modes. Their life cycles often include both vertical (parent-to-offspring) and horizontal transmission (between individuals), making them significant in host-parasite ecology.^[2]

Hosts and life cycle

Amblyosporidae primarily parasitize mosquitoes (e.g., Aedes, Culex) and copepods (e.g., Mesocyclops, Acanthocyclops). Their life cycle is complex, involving multiple developmental stages and hosts:

• In copepods: Infections occur in female ovaries, producing orally infectious spores through binary and multiple fission, often leading to host death.^[3] Infection rates in copepods can range from 15.0% to 57.1% annually.
• In mosquitoes: Both sexes are infected, with development in testes (males) and ovaries (females). Vertical transmission occurs via infected eggs, while horizontal transmission involves spore consumption. Prevalence in mosquitoes varies, with vertically acquired infections in Aedes communis ranging from 1.6% to 3.6%, and horizontally acquired infections reaching up to 69.0% in males.^[3]

The life cycle includes haplophasic and diplokaryotic stages, with sporogony producing distinct spore types, such as binucleate spores for vertical transmission and meiospores in male mosquito larvae.^[3]

Ecological and applied significance

Amblyosporidae play a significant role in the ecology of their hosts, particularly in regulating copepod and mosquito populations. Their high prevalence in natural populations, such as over 50% weekly infection rates in copepods from May to September, can impact host reproduction and survival.^[4] Their infection of mosquitoes, vectors of human diseases, makes them of interest for biological control strategies, although their complex life cycles pose challenges for practical application.

Phylogeny

Phylogenetic studies suggest that Amblyosporidae exhibit cospeciation with their hosts, with species like Amblyospora forming monophyletic groups with mosquito hosts.^[5] However, the genus Amblyospora is paraphyletic, with some species, such as Amblyospora californica, forming sister taxa to others.^[5] This complexity highlights the evolutionary adaptability of Amblyosporidae to diverse host environments.

Genera

• Aedispora
• Amblyospora
• Andreanna
• Becnelia
• Crepidulospora
• Cristulospora
• Culicospora
• Culicosporella
• Dimeiospora
• Edhazardia
• Hyalinocysta
• Intrapredatorus
• Novothelohania
• Parastempellia
• Parathelohania
• Trichoctosporea
• Tricornia