WELCOME

Apart from biological processes such as

protein biosynthesis or tissue but also

does…

EXTENDED PHENOTYPE

Architectural constructions Action at a distance of the parasite on its host.

Host parasitic interaction.

Host Parasitic interactions

Cymothoa exigua Sacculina

Guinea WormFilarial Worm

ANT

FUNGUS

ZOMBIE ANTS – A DEATH RIDE

Ant: Camponotus leonardi

• Found in Thailand evergreen forests

• Canopy dwelling ant

• Diurnal insects - 9.30 am – 12.45 pm

Fungus : Ophiocordyceps unilateralis

Kingdom: Fungi

Division: Ascomycota

Class: Sordariomycete

Order: Hypocreales

Family: Ophiocordycipitaceae

Genus: Ophiocordyceps

Species: O. unilateralis

• Obligate parasite• High humidity and low temperature• O. unilateralis targets a specific host species, the Camponotus leonardi ant• Parasite that requires ants for reproduction

Steps towards death ride…

(Pontoppidan et al., 2009)

Leaves out of the trail

(Andersen et al., 2009)

Infected ants - average of 99 leaves (range 52-239, 8 focal ants)

Trail ants - average 51 (range 8-140, 13 focal ants)

DEATH GRIP

(Andersen et al., 2009)

Little bit exciting on death grip …

• Timing - 9.30am to 12.45pm

• Location of on plant – North-Northwest side

• Abaxial surface of the leaf (98%)

• Abaxial leaf surface - Midrib (63%) Side vein (35%)

Margin (2%)

(Andersen et al., 2009)DEATH GRIP = 25 ± 3 cm

Focal animal observation periodogram of ants infected by Ophiocordyceps unilateralis

David et al., 2011

Synchronized manipulation of ants by fungus: A sun position chart of the death grip

David et al., 2011

In search of WHY???

• Why fungus directs the ant to moves towards saplings rather than tree canopy?

(Andersen et al., 2009)

In search of WHY???

• Why fungus does not infect directly to whole colony?

Worker ant quickly remove the dead mates

• Why death grip is seen always at lower surface of leaf?

To increase the parasitic transmission

(Andersen et al., 2009)

(Hughes et al., 2009)

In search of WHY???

• Why Cordyceps targets the insects?

• Fungi have Osmotrophic growth, where excreted enzymes mediate the external breakdown of the substrate by secondary metabolites followed by uptake of sugars and amino acids.

• This ability facilitates the shift in O. unilateralis from using live tissue to dead tissue, and such a parasite strategy requires exploitation strategies in living hosts that ultimately maximize fitness returns from dead hosts.

(Andersen et al., 2009)

Post – Death grip stage

• Ants could remain alive for as long as six hours after biting.

• Fungus affected ant – non aggressive compared to normal ant of same species

• After biting into leaves infected ants always died as this is a developmental necessity for the subsequent growth of the fungus.

(Andersen et al., 2009)

Rise of the fungus… Fall of an ant…

• Within 24 h after death Hyphal growth – Unsclerotized parts and tarsi Pluffy appearance

• 3 days – 3 weeks Stroma length 3–5 mm Entire ants were covered in a dense mat of hyphae Later turned brown, a characteristic color for Ophiocordyceps species Later complete stromal development takes within 2 – 4 weeks

• 3 weeks later Stroma had reached a length of 10 mm∼ Development of a unilateral perithecial plate on the stroma – Sexual spore discharge

(Andersen et al., 2009)

What happens inside the ant?

• After 48 hours of death - high density of fungal tissue with a combination of hyphal growth and yeast like cells.

• No evidence of cuticle degradation - both the exoskeleton and the head tentorium were undamaged.

• Immediately after the death grip – fungus changes the internal texture of the mandibles.

(Pontoppidan et al.,2009)

Muscular atrophy: Head is filled with fungal cells

What happens inside the ant?

• The fungal cells, called hyphal bodies - found between the muscle fibers and surrounding the brain and post pharyngeal gland but not inside muscles, brains or glands.

Heads of manipulated ants colonized by fungi.

(Sylvia et al., 2009)

• Muscles of the mandibles were atrophied within 48 hours of the infection.

Mandibular atrophy: Most prominent sign of infection inside the head capsuleM

andi

bula

r mus

cles

HEALTHY

INFETED

Intrafibrular space

Muscle fiber

Fungal hyphal bodies

Mandibular atrophy: Mandibular opening and closing muscles

Infected Healthy

• Once the ant has become attached, the muscles apparently atrophy rapidly inducing the characteristic lock-jaw followed by the death of the host.

• Thus while energy and ions for normal functioning are not present the atrophy likely functions to imbed the mandibles deep into the plant tissue due to this atrophy

(Sylvia et al., 2009)

Sections of entire ant after 4 – 5 weeks of dead grip

Its time to emerge out…

(Sylvia et al., 2009)

Fossils, a window to the past…

Fossil leaf (SM.B.Me 10167), 47 mya from Messel(David et al., 2011)

Year Price/kg (Rs.)

1980s 18,300

1997 85,500

2004 3,66,800

2005 6,11,400

2013 50,95,500

Cordyceps, the most precious…

Cordyceps sp. : A drug for many…

Anti - agingHypoglycemicAphrodisiacKidney and lung problemsCancerHyperglycemiaHyperlipidemia

Other heart diseases and liver disease

(Sung et al., 2009)

Medicinal products

CONCLUSION…

Thank you...