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Myrmarachne smaragdina Ceccarelli, 2010

A small to medium-sized, slender spider in rainforest and open woodland in northern Australia. The female nearly perfectly mimics the green ant, Oecophylla smaragdina. It is an example of Batesian mimicry where the mimic has evolved to resemble relatively unpalatable animals to appear unpleasant to predators. This spider lives near colonies of green ants, when it gets too close it may be attacked - if so, it flees. The species names come from the ant it mimics, which in turn refers to the yellow-green colour of the ant's gaster. The hugely elongated chelicerae of the male, thought to resemble a food parcel or larvae, as an ant would carry them, are about the same length as its carapace. To our eyes the male is not as successful in its mimicry, but it is not known whether its predators are capable of spotting it more easily than the female. Males used their englarged, spiny chelicerae in combat, which may be selecting for larger chelicerae if victory in combat leads to mating success. Retreats are usually built on the upper surface of leaves, the males building sheet-like retreats, and the females building woolly-looking ones. (Ceccarelli, 2010, 2009, 2008) ♀ 6mm ♂ 6mm

Female, Darwin


Myrmarachne smaragdina Ceccarelli, 2010
Photo: Dr Greg Anderson

Female, Darwin GJA-6706


Myrmarachne smaragdina Ceccarelli, 2010
Photo: Dr Greg Anderson

Male adult from above facing left, Cairns IRM-117


Myrmarachne smaragdina Ceccarelli, 2010
Photo: Robert Whyte

Male adult from above facing right, Cairns IRM-117


Myrmarachne smaragdina Ceccarelli, 2010
Photo: Robert Whyte

Male adult from below with palp, Cairns IRM-117


Myrmarachne smaragdina Ceccarelli, 2010
Photo: Robert Whyte

Penultimate male with final moult AUS-2171


The penultimate male looks exactly like the female - the change to the adult form being massive and dramatic. It begs the question, where does all this new material hide during the final moult? Does it grow rapidly, unfold, inflate?

Salticidae Myrmarachne smaragdina
Photos: Iain R. Macaulay

Female Darwin 19/01/13 AUS-0667


Salticidae Myrmarachne smaragdina
Photo: Robert Whyte

Female AUS-0667 Darwin 19/01/13 waving front legs like antennae


Salticidae Myrmarachne smaragdina
Photo: Robert Whyte

Male Crystal cascades, Nr Cairns 23/02/13 AUS-0872


Salticidae Myrmarachne smaragdina
Photo: Iain R. Macaulay

References


Cecarelli, 2010 New species of ant-mimicking jumping spiders of the genus Myrmarachne MacLeay, 1839 (Araneae: Salticidae) from north Queensland, F Sara Ceccarelli, School of Marine and Tropical Biology, James Cook University, Townsville, Qld 4811, Australia.Australian Journal of Entomology (2010) 49, 245-255

Ceccarelli, 2009 Ant-mimicking spider, Myrmarachne species (Araneae : Salticidae), distinguishes its model, the green ant, Oecophylla smaragdina, from a sympatric Batesian O. smaragdina mimic, Riptortus serripes (Hemiptera : Alydidae) Fadia Sara Ceccarelli School of Marine and Tropical Biology, James Cook University, Townsville, Qld 4811, Australia.CSIRO PUBLISHING www.publish.csiro.au/journals/ajz Australian Journal of Zoology, 2009, 57, 305-309

Ceccarelli, 2008 Behavioral mimicry in Myrmarachne species (Araneae, Salticidae) from North Queensland, Australia Fadia Sara Ceccarelli: School of Tropical Biology, James Cook University, Townsville, QLD 4811, Queensland, Australia. 2008. The Journal of Arachnology 36:344-351

 

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