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Ant thread? Ant thread! Thanks for making this happen, GAG. I've been enjoying reading through the past couple pages; what with excellent Q/A, setup photos, and discussion of ants in media. I was particularly pleased to see mention of Bernard Werber's bizarre novel Empire of the Ants (AKA Watership Down with ants), and agree that everyone should experience that book at some point! Also, the fact that every other book/documentary/game having to do with ants is named "Empire of the Ants" never fails to be amusing and/or confusing.  ----- ninjewtsu posted:iirc i once heard/read that there's tons of ants living under the ocean (underwater? or merely subterranean beneath the seabed?), potentially more than exist on land. i can't find anything backing this up on google so maybe it doesn't exist and i'm full of poo poo, but in any case do ants have any interesting interactions with large bodies of water? i know there's the famous antrafts but is that all there is to it, or is there more to ants and water than that? Ants and the ocean?!  GAG already covered how the rafts work and the ability of ants to "hold their breath" in water, but there actually are instances of marine ants! Well, quasi-marine: There are several species that make their homes in the tidal zone, and have developed various adaptations to survive the daily inundations by the tide. One such species, Polyrhachis sokolova, inhabits the tidal mangrove mudflats of Australia and New Guinea, which are submerged by seawater twice daily. Their light bodies are able to walk on the surface tension, but they will also sometimes dip their front legs beneath the surface to "swim", steering with their trailing back legs. What's more shocking is that the nests of these ants actually lie below the high-tide line, meaning that twice a day, the entire nest is submerged by the sea! The nest entrance is constructed in a manner so as to collapse and prevent the water from pouring straight in, and certain chambers are built to trap air even as less air-tight passages slowly fill. https://www.youtube.com/watch?v=Er-OnJCn1gg While P. sokolova has taken the sink trap / diving bell approach to surviving the tide in their mud nests, another tidal species in Australia (Colobopsis anderseni) actually blocks up the narrow entrance to their mangrove tree-twig nest with a plug-headed individual:  During the periods in which a tidal ant nest is submerged, CO2 levels can become very elevated, and there are studies that have found some tidal species can enter into anaerobic respiration, still continuing to produce CO2 while no longer consuming the trace oxygen in the trapped pockets of the nest. So there you have it! The truth about the colony of Antlantis, which sinks beneath the waves twice daily. It only goes to support GAG's declaration that the ants of Australia are those of another world. Thank you for permitting my geekery of ants and the ocean to overlap! 
Alehkhs fucked around with this message at 18:35 on Jul 15, 2020 |
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StrixNebulosa posted:Holy cow, I didn't think I'd see an ant swim today. How the hell do they do that?  The more serious answer is that there are many species beyond just those in the tidal zone that demonstrate water-walking and/or swimming behaviors, and they all seem to have slightly different methods - but the underlying mechanics are still not fully understood. The above figure actually comes from a paper examining the methods of a couple of species found in Kentucky: https://academic.oup.com/aesa/article/111/6/319/5054178 Gripshover et al. posted:Some F. subsericea workers walked across the water surface (i.e., with the body elevated above the surface and legs supported by surface tension), whereas others ‘swam’ (i.e., with the ventral surface of the body in contact with the water surface and legs penetrating the surface film). Despite this conspicuous behavioral difference (walking vs swimming), ants in the two groups did not differ conspicuously in morphology or swimming performance. The average body length and hind leg tarsus length of walking workers were somewhat shorter than those of swimming workers (Table 4). However, no other individual legs or leg parts differed between them (t < 1.83, df ≥ 27, P = 0.08). Mass also was similar between the groups, and overall morphometrics were only marginally different between them (Fig. 4; pseudo-F = 2.66, df = 1, 52, P = 0.054). In terms of swimming performance, walking workers exhibited higher maximum velocity, but walking and swimming individuals had similar overall velocity, maximum acceleration, and efficiency (Table 4). ----- Edit: Here's another great shot of a swimming ant, courtesy of a different study comparing the swimming abilities of 35 species (https://jeb.biologists.org/content/217/12/2163): https://www.youtube.com/watch?v=41fALZbG5Wk quote:In real time, this ant (Odontomachus bauri) is moving about eight times faster across a pan of water than the video shows. This species moves quickly to rescue itself, but about half the species in a recent test just flailed and struggled. The background grid is composed of 1-by-1 centimeter squares. There's several other videos and some photo breakdowns in the article, so check it out: https://jeb.biologists.org/content/217/12/2163 Alehkhs fucked around with this message at 18:15 on Jul 15, 2020 |
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Jul 15, 2020 17:36
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