biology

Metarhizium anisopliae

Metarhizium anisopliae is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Metarhizium anisopliae rather than just read about it. In short: Metarhizium anisopliae is a fungus, the type species in the Metarhizium genus. It grows naturally in soils throughout the world and causes disease in various insects by acting as a parasitoid.

Key takeaways

Metarhizium anisopliae belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Metarhizium anisopliae to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Metarhizium anisopliae from memory before moving on to harder problems.

Reference excerpt

Metarhizium anisopliae is a fungus, the type species in the Metarhizium genus. It grows naturally in soils throughout the world and causes disease in various insects by acting as a parasitoid. Ilya I. Mechnikov named it Entomophthora anisopliae after the insect species from which it was originally isolated – the beetle Anisoplia austriaca and from these early days, fungi such as this have been seen as potentially important tools for pest management. It is a mitosporic fungus with asexual reproduction.

Synonymy The taxonomy of the Metarhizium has been subject to many reviews since the 1990s, before which the genus consisted of less than ten "species", based on morphological characteristics only. Many isolates have long been recognised to be specific, and some were initially assigned variety status, with M. anisopliae sensu stricto, M.a. var. major, M.a. var. lepidiotae and M.a. var. acridum (the latter included important isolates used for locust control). However, they have now been assigned as new Metarhizium species in light of newer molecular evidence and subsequent work. The commercially important isolate M.a. 43 (or F52, Met52, etc.), which infects Coleoptera and other insect orders has now been assigned to Metarhizium brunneum.

Biology The disease caused by the fungus is sometimes called green muscardine disease because of the green colour of its spores. When these mitotic (asexual) spores (called conidia) of the fungus come into contact with the body of an insect host, they germinate and the hyphae that emerge penetrate the cuticle. The fungus then develops inside the body, eventually killing the insect after a few days; this lethal effect is very likely aided by the production of insecticidal cyclic peptides (destruxins). The cuticle of the cadaver often becomes red. If the ambient humidity is high enough, a white mould then grows on the cadaver that soon turns green as spores are produced. Most insects living near the soil have evolved natural defenses against entomopathogenic fungi like M. anisopliae. This fungus is, therefore, locked in an evolutionary battle to overcome these defenses, which has led to a large number of isolates (or strains) that are adapted to certain groups of insects.

Economic importance The previously described range of entomopathogenic fungus isolates known as M. anisopliae, before 2009, had been observed to infect over 200 insect pest species. M. anisopliae and its related species are used as biological insecticides to control a number of pests such as termites, thrips, etc. and its use in the control of malaria-transmitting mosquitoes is under investigation. A modified form was reported to kill 90% of females who mated with infected males in a study in Burkina Faso. M. anisopliae does not appear to infect humans but has been reported as a significant pathogen of reptiles. The microscopic spores are typically sprayed on affected areas. A possible technique for malaria control is to coat mosquito nets or cotton sheets attached to the wall with them. According to Paul Stamets, species such as this could prevent colony collapse disorder and catastrophic famine. A simplified method of microencapsulation has been demonstrated to increase the shelf-life of M. anisopliae spores commercialised for biological control of pest insects, potentially increasing its efficiency against red imported fire ants. The species has been shown to convert elemental lead, an environmental pollutant, into the much less toxic pyromorphite, thus showing its potential use in decontamination.

Important isolates Some isolates previously placed here have been assigned to Metarhizium robertsii; others may include:

The ex-neotype isolate of M. anisopliae is IMI 168777ii = ARSEF 7487 (also CSIRO FI-1029) from Schistocerca gregaria in Eritrea A.C. Rath's isolate F506 (= ARSEF 4556; DAT 506; IMI 384583) from Boophilus sp. (Acari: Ixodidae) in USA (Florida) M. anisopliae isolated from Dermolepida albohirtum (Coleoptera: Scarabaeidae) include: CSIRO FI-1358 (= ARSEF 7493) and FI 1045 which is the active ingredient of 'Biocane'.

See also LUBILOSA Beauveria bassiana, the fungus that causes white muscardine disease in various insects

References

External links [1] Fungi Make Biodiesel Efficiently at Room Temperature

Illustrations

Worked examples

Example 1 — a first encounter with Metarhizium anisopliae

Start with the simplest possible case. Write down what Metarhizium anisopliae claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Metarhizium anisopliae before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Metarhizium anisopliae ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Metarhizium anisopliae

In research: Metarhizium anisopliae appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Metarhizium anisopliae in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Metarhizium anisopliae is common in secondary-school and first-year university syllabi. It links to neighbouring topics Clavicipitaceae, Fungi described in 1879, Fungus species, so understanding it makes those chapters shorter.
In everyday life: Look for Metarhizium anisopliae outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Metarhizium anisopliae in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Metarhizium anisopliae means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Metarhizium anisopliae out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Metarhizium anisopliae in simple terms?

Metarhizium anisopliae is a fungus, the type species in the Metarhizium genus. It grows naturally in soils throughout the world and causes disease in various insects by acting as a parasitoid.

Why does Metarhizium anisopliae matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Metarhizium anisopliae?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Metarhizium anisopliae.