New Zealand Journal of Zoology abstracts

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The natural history of Myrmarachne melanotarsa, a social ant-mimicking jumping spider

Robert R. Jackson^1,2

Ximena J. Nelson^1,3,*

Kathryn Salm¹

¹School of Biological Sciences
University of Canterbury
Private Bag 4800
Christchurch 8140, New Zealand

²International Centre of Insect Physiology and Ecology (ICIPE)
Thomas Odhiambo Campus
PO Box 30
Mbita Point, Kenya

³Centre for the Integrative Study of Animal Behaviour
Macquarie University
Sydney, NSW 2109, Australia

*Author for correspondence: ximena.nelson@canterbury.ac.nz.

Abstract Myrmarachne melanotarsa, an ant-like jumping spider (Salticidae) from East Africa, is an accurate mimic of Crematogaster sp. and associates unusually closely with its models. M. melanotarsa is remarkable in that it forms dense aggregations and builds large nest complexes (numerous individually-occupied nests connected to each other by silk). Other salticids (Pseudicius spp., Menemerus spp.) live with M. melanotarsa in the same nest complex. These aggregations, which can exceed 50 conspecific individuals per colony, are considerably larger than those few previously described, and seem to have primarily a protective function. We provide baseline information on the natural history of M. melanotarsa, paying particular attention to predatory behaviour and association with Crematogaster sp., and fit this within current theory on the function of sociality in spiders. Other unusual behaviour of M. melanotarsa includes “mouthing”, in which the spider opens and closes its chelicerae while pressing its mouthparts against nest silk. We investigated the role of prior presence of Crematogaster sp. on nest silk in eliciting this previously unreported behaviour.

Keywords Batesian mimicry; Crematogaster; Myrmarachne; Salticidae; social spiders

Z07052; Online publication date 1 July 2008; Received 23 October 2007; accepted 8 March 2008
New Zealand Journal of Zoology, 2008, Vol. 35: 225–235
0301–4223/08/3503–0225 © The Royal Society of New Zealand 2008

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