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The inter-tidal ant, Polyrhachis sokolova swims using its first pair of legs similar to the way we use our arms. Pallarenda, Townsville, QLD

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The mudflat habitats of these ants in Townsville, Queensland, are possibly one of the only places on Earth where one finds ants, mudskippers and fiddler crabs foraging in the same location.

Workers of the inter-tidal ant Polyrhachis sokolova feed on a dead crab, Townsville, QLD

A male fiddler crab in the mudflats. Townsville, QLD

A mudskipper during high tides in the mudflats, Townsville, QLD

These ants of course love sea food, and dead crabs are much appreciated by them. However we found that in addition to the dead crabs they really dig the maggots found within the crabs.  On more than one occasion, individual workers dragged live maggots out of the dead crabs and took them home. This was the only occasion where ants carried live prey back home (I presume maggots can only be food for these ants).

A worker of the inter-tidal ant, Polyrhachis sokolva captures a live maggot found within a dead fiddler crab. Townsville, QLD

Workers of the inter-tidal ant, Polyrhachis sokolva capture a live maggot they found within a dead fiddler crab. Townsville, QLD

The mudskippers, though cute, were an annoyance a times. We had trained ants to a food source, which were delicious clams. Often the mudskippers were bold enough to skip and take over the clam, much to the ants (and our) surprise and dismay. The perplexed ants would be then left searching for their lost food source, whose location they were most certain until their neighbour came over.

Ant gallery gets an update with the inter-tidal ant, Polyrhachis sokolova. Go check it out.

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Drove up from Canberra all the way to Townsville a few days ago. Stopped along the way at several places hunting and photographing ants along inland Australia. This was my first road trip along this route and it was thoroughly entertaining. Found a stunning Myrmecia Jack Jumper Queen in the Floral garden of Gilgandra. Also found in the same place the super cool Opisthopsis ants, which have their large eyes placed at the posterior region of the head.

enroute to Townsville

Somewhere along the way from Canberra to Townsville

Myrmecia Queen (jack jumper)

Queen of a Jack Jumper, Myrmecia species, Floral Garden – Gilgandra, NSW

Strobe ant, Opisthopsis species, Floral Garden – Gilgandra, NSW

Mission Townsville: The world’s only inter-tidal ant, Polyrhachis sokolova calls Townsville home and so have I for a few weeks. The plan is to identify the homing strategies of these ants. The challenge for these ants is not only to find the tiny little nest entrance at the base of the mangroves, but to also get there often by swimming, yes that’s right, by swimming. First and foremost, I am hoping to tackle the foraging strategies on the ground and will then attempt to unravel the swimming part of the story. Have had five fantastic days of fieldwork so far and its getting better by the day. Now if someone could only get rid of the sandflies…

The inter-tidal ant, Polyrhachis sokolova, tears apart a dead crab. Townsville, QLD

Workers of the inter-tidal ant, Polyrhachis sokolova, transfer maggots found in a dead crab. Townsville, QLD

Oecophylla smaragdina, Townsville, QLD

An angry worker of the green tree ant, Oecophylla smaragdina agitated by the intruding photographer

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New Pictures: Myrmecia

The ant gallery gets updated with males and workers of a bunch of Myrmecia ants, the renowned Australian bullants and jackjumpers. The large eyes and ocelli (simple eyes), especially in the male ants are worth drooling.

Worker of the bull ant Myrmecia tarsata bares its jaws at the intruding photographer

The handsome males of Myrmecia pyriformis fly during the day in search of a mate, whereas its own workers are exclusively nocturnal foragers

Have a look here

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Image

Photo credit: Jurgen Otto

Read this story about how an amateur photographer spots a cool Peacock spider, posts it on Flickr and it turns out to be a new species! Very cool.

In Canberra times

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Here is a cool Trap jaw ant, Orectognathus. These are Dacetine ants, known from Australia and Southeast Asia. They typically nest is soil. One of our recent visitors in the lab, Marc Seid, found and collected a colony of these ants with their brood and a queen from Murramarang National Park, NSW. Strangely enough, the workers did not feed on collembolans that I provided them, but only fed on maple syrup. With just this food source, the colony has survived over the last 2 months with no fatalities.

Update: More pictures of Orectognathus here.

Photo: 

Minor worker of Orectognathus species with its larvae, photographed in the lab.

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After having spent several days of nocturnal lifestyle studying the Bull ant, Myrmecia pyriformis in Canberra, I am quite pleased to report that one of our findings has been published. Our earlier discovery that these ants exhibit strong bursts of inbound and outbound activity in evening and morning twilight respectively in the summer, prompted us to ask whether the onset activity of these ants is restricted to the twilight period for the whole year and if so how do they determine the time of the day in such a dim-lit temporal niche.

By regular monitoring of activity schedules at different nests it became clear that temperature does not play a major role in this – a factor thought to play a major role in regulating ant foraging. Of course when surface temperature dropped to 6.5°C the ants decided to take a break (thankfully for us!), which indicated that this might be close to their critical minima – that’s another story.

The interesting bit here was that in overcast conditions (determined by measuring light levels) ants began their activity much earlier relative to sunset time and conversely under clear skies began activity much later. This indicated that light intensity might play a role in the timing of foraging and that the setting sun alone was not a cue to begin activity.

Inspired by Edward Hodgson’s observations in 1955 on leaf cutter ants3 we set about modifying light intensity during twilight. The challenge of was to make the twilight brighter ensuring no point light sources would be available for orientation. We did this by using a dome shaped diffuser and suspending it above the nest entrance. This also ensured that if the ants came close to the nest entrance the visual panorama was still available for them to navigate. Keeping the lights on for the first 60 minutes of the twilight did not result in ant activity. As soon as the lights were turned off, activity began within a few minutes. The necessary controls were carried out and replication at three nests provided very similar results.

Publications in Proceedings B is currently available for free download as they are celebrating their 350th anniversary. So go on and download this paper.

Narendra A, Reid SF & Hemmi JM. 2010. The twilight zone: light intensity triggers activity in primitive ants. Proceedings of the Royal Society, Biological Sciences. doi: 10.1098/rspb.2009.2324

Hodgson ES 1955. An ecological study of the behaviour of the leaf-cutting ant Atta cephalotes. Ecology 36: 293-304

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