#hirsutella

[nerdyguy94]

Ophiocordyceps unilateralis - The Zombie Ant fungus

So I’m kicking off my geeky biology facts with an old favourite. This was one of the first things that blew my mind at university and I still find it fascinating and exciting to this day. This is Ophiocordyceps unilateralis…

Ophiocordyceps unilateralis is a fungal pest that infects insects and changes the behavioural patterns of the host. Using ants as an example (as they are the most common insect to be infected by this fungus) the infected ant will leave its canopy nests and foraging trails for the forest floor, an area with a temperature and humidity suitable for fungal growth, here the ant will fix its mandibles into the vein of a leaf and stay there till death (1). The death of the ant is not a quick process however, it can take up to 4 - 10 days for the ant to die, within this time the fungus undergoes a fruiting and reproductive phase. Here the fungus grows and “blossoms” (for want of a better word) by erupting from the ants head and/or thorax! At this time, O. unilateralis releases spores to the surrounding area, to then infect another insect.

If you were born in the 90’s or a bid nerd like me you might think “that sounds familiar” and that's because it is the basis of this Pokemon line …

Yep even back when Pokemon started, they used this concept to design one of the original pokemon, it is literally an insect with a parasite in it and as the parasite grows it takes over the mind and zombifies it - hence the white eyes on Parasect.

Back to the ants, as this is such a destructive parasite to an ant colony, the ants have developed a way to detect or sense when a member is infected, the healthy ants then carry the infected ant away from the colony and the normal paths the ants take, as to not infect any more of the colony when the fungus erupts and spreads spores around the colony (2,3)

Finally it’s not just the ant that has to fight through this infection, the fungus also has to put in a lot of work to get to the fruiting stage. The fungus must first attach securely to the arthropod exoskeleton and penetrate it—avoiding or suppressing host defenses—then, control the behavior of the host before killing it; and finally, it must protect the carcass from microbial and scavenger attack(4). To me this is very fascinating fungus and was one of the things that made me go “wow” at University because it can show you how much of a horror nature can be.

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So I’m thinking of doing these every monday, i feel like it should have a title to it or a hashtag to it but for now I’ll just call it a geek out for now as that is what it is. Let me know if you like these and want to see more or if you have any topics you want me to cover.

References

1) Mongkolsamrit, S., Kobmoo, N., Tasanathai, K., Khonsanit, A., Noisripoom, W., Srikitikulchai, P., Somnuk, R., Luangsa-ard, J. J. (2012). "Life cycle, host range and temporal variation of Ophiocordyceps unilateralis/Hirsutella formicarum on Formicine ants". Journal of Invertebrate Pathology. 111 (3): 217–24

2) Pontoppidan, M. B., Himaman, W., Hywel-Jones, N. L., Boomsma, J. J., Hughes, D. P. (2009). "Graveyards on the move: The spatio-temporal distribution of dead Ophiocordyceps-infected ants". PLoS ONE. 4 (3): e4835.

3) Sung, G. H., Hywel-Jones N. L., Sung, J. M., Luangsa-Ard, J. J., Shrestha, B., Spatafora, J. W. (2007) "Phylogenetic classification of Cordyceps and the clavicipitaceous fungi". Studies in Mycology. 57 (1): 5–59.

4) Evans, H. C., Elliot, S. L., Hughes, D. P. (2011) "Ophiocordyceps unilateralis – A keystone species for unraveling ecosystem functioning and biodiversity of fungi in tropical forests?". Communicative Integrative Biology. 4 (5): 598–602

Pictures obtained from google.

[bookpiofficial]

Analysis of Technology Gaps on Integrated Management of Major Pests of Jasmine (Jasminum sambac L.) of Tamil Nadu | Chapter 01 | Emerging Issues and Development in Economics and Trade Vol. 2

Investigations were conducted during 2015-2016, in major jasmine growing districts of Tamil Nadu, for assessing the distribution, infestation level and the relative importance of the major pests of jasmine viz., blossom midge, Contarinia maculipennis, budworm, Hendecasis duplifascialis, leaf webworm, Nausinea geometralis and two spotted mite of jasmine, Tetranychus urticae. Majority of respondents were aware of the major jasmine pests, among which 53 per cent respondents ranked budworm as the most important pest, 16 per cent as blossom midge, 9 per cent as two spotted mite and 7 per cent as leaf webworm as major pest. The incidence of major pests of jasmine viz., blossom midge, budworm, leaf web worm and two spotted mite were observed in all the surveyed districts of Tamil Nadu in varying intensity. The incidence of these pests was higher in Madurai district recording 34.27, 35.18, and 28.75 per cent of midges, budworm, leaf webworm and 10.25 two spotted mites per 2 cm2 leaf area, followed by Tirunelveli district recording 33.19, 31.35 and 25.36 per cent incidence of midge, budworm, leaf webworm and 9.47 two spotted mites per 2 cm2 of leaf area. Regarding the temporal incidence of the major jasmine pests, jasmine growers perceived the maximum incidence from May - August for budworm/mites and September-November for midges/leaf webworm. The least incidence was from February-April. Cultural control measures like pruning of bushes and field sanitation was followed by majority of jasmine growers, thus recorded lower technology gap index (TGI) of 9 and 14 per cent. Other cultural practices like collection and destruction of fallen and discoloured buds/flowers, setting of light traps, setting of yellow sticky traps, regular weeding, regular tilling or raking of soil to destroy pupae, non-planting of alternate hosts around main cropped area, planting inter/border crops recorded maximum TGI of 82, 73, 79, 59, 85 and 87 per cent respectively indicating their unawareness. Regarding the usage of bio-control agents, only 8 per cent respondent’s attempted Chrysoperla eggs which is a common natural enemy for all major jasmine pests with a TGI of 92 per cent. Usage of entomopathogenic fungi, Metarrhizium anisopliae for midges, Beauveria bassiana for lepidopterans and mites, Hirsutella thompsonii for mites recorded higher TGI of 90, 87 and 90 per cent projecting the unawareness of the growers. Bacterial biopesticide, Bt was used by only 16 per cent respondents and Trichogramma egg cards was used by only 14 per cent respondents recording higher TGI of 84 and 86 per cent. With regard to the use of synthetic chemical insecticides/acaricides, respondents recorded medium TGI showing their awareness but the right frequency in application of chemical pesticides recorded very high TGI of 91 per cent showing the indiscriminate usage of chemicals in jasmine ecosystem. Thus, efforts should be taken to create awareness among jasmine growers for the use of eco-friendly bio-control methods against major pests of jasmine.

Author(s) Details

I. Merlin Kamala Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore -641003 Tamil Nadu, India.

I. Isaac Devanand Department of Agricultural Extension, Annamalai University, Chidambaram-608001, Tamil Nadu, India.

View Books: http://bp.bookpi.org/index.php/bpi/catalog/book/96

[eurekamag--com]

Lack of per os toxicity or pathogenicity in rats fed the fungus Hirsutella thompsonii

http://dlvr.it/NsS1X3

[eurekamag--com]

Hirsutella thompsonii a fungal parasite of the Citrus rust mite Phyllocoptruta oleivora in the Rio Grande Vall

http://dlvr.it/NbnkcX

[eurekamag--com]

A liquid medium for the large-scale production of Hirsutella thompsonii in submerged culture

http://dlvr.it/NNXfcb