sahara desert ant adaptations


[The] sky has a very low radiative temperature, Yu explains.

The sequence of swing and stance movements of the six legs was visualized by podograms (Fig. Morphometric comparisonof C. bombycina and C. fortis alitrunk and leg pair (Lp) lengths. All data (n=177 runs) were obtained during the summer months of 2015 and 2016. Yus teams models show that the structure of the micron-thick hairs gives them the heat shielding powers. The onset of swing (Fig. We expanded the range of recorded walking speeds in C. bombycina beyond the known limits (Wehner, 1983; Zollikofer, 1994), to more than 800mms1, and assessed the contribution of different spatial and temporal walking parameters to achieve such speeds and examined in detail gait and leg coordination patterns to gain a deeper understanding of the silver ant's walking behaviour. Depending on body length, walking speed and ambient temperature, Reynolds numbers for C. bombycina range from about 140 (for an 8mm ant walking at a medium speed of 300mms1 at 45C) to 570 (for an 11mm ant walking at the maximum speed of 840mms1 and a moderate temperature of 30C). Example videos are available from ResearchGate (doi:10.13140/RG.2.2.21093.45282 and doi:10.13140/RG.2.2.12704.84488) and an extracted single image for each video is shown in the supplementary information (Fig. Moreover, the fluid granular sand medium may impede locomotion and demands considerable energy to cross. But thats just the beginning. Morphologically, C. bombycina is well adapted through a number of features characteristic of the genus Cataglyphis. As for the two Cataglyphis species, different arthropod taxa appear to behave differently at high speeds, with some tending towards more metachronal patterns and some species strengthening the synchronization of leg swings (which might require specific features for elastic energy storage in the legs; Weihmann et al., 2017; Weihmann, 2018). In C. bombycina, the front and hind leg duty factor dropped below 0.5 at rather low walking speeds, below 100mms1. Further, each evaluated recording had to consist of at least three complete step cycles per leg. Movement of the COM was tracked to analyse its horizontal velocity and acceleration (see FigsS4 and S5). We averaged the values recorded in all six legs of an ant to obtain mean values that illustrate general relationships (see Fig. Duty factor is the duration of the stance phase of a leg divided by the entire duration of the respective step cycle, stance and swing phase together.

High-speed video equipment (Mikroton MotionBlitz Mini1 high-speed camera, Mikroton, Unterschleissheim, Germany) allowed sampling rates of 5001000imagess1. Levene's test, realized with Excel (Microsoft Corporation, Remond, WA, USA), was used to compare the variances in footprint positions. Already a subscriber? All measurements in C. bombycina were performed under a dissection microscope (Stemi SV6, Zeiss Microskopy GmbH, Jena, Germany) with a measurement eyepiece calibrated with a stage micrometre. Shorter leg lengths are compensated for by high stride frequencies, ranging beyond 40Hz. improve functionality and performance. The Monitor is a peculiar little publication thats hard for the world to figure out.

Ant-Mans cool. This is slightly below the minimum of 19ms in C. fortis. ; Writing - original draft: S.E.P., V.L.W. To analyse the characteristics of silver ant (Cataglyphis bombycina Roger 1859) locomotion, we compared its morphometry and walking behaviour with that of another desert ant species, Cataglyphis fortis (Forel 1902). In this JEB-sponsored episode, they discuss the concept of symmorphosis and the evolution of the oxygen cascade. Standard deviations of footfall positions were used to quantify the spread of footprint positions (footprint clustering in Fig. Stance and swing movements are repetitive events in the step cycle. Synchronization of legs can lead to aerial phases (as a classical definition for the walkrun transition; Hildebrand, 1985), appropriate to several arthropods such as Periplaneta americana (Full and Tu, 1991), ghost crabs (Burrows and Hoyle, 1973) or Hololena spiders (Spagna et al., 2011). The respective leg lengths were taken as the sum of femur, tibia and basitarsus measurements (e.g. Latest book reviews, author interviews, and reading trends. For all evaluated recordings, the mean walking speed was calculated as the distance covered from the start of the first step cycle to the end of the last step cycle in a given video sequence, divided by the time needed to cover that distance. After all, brief and fast movements in these small animals should occur at low Reynolds numbers and high substrate viscosity. For multiple comparisons of normally distributed data, we used a one-way ANOVA (with Holmidk method as post hoc test); for non-normally distributed data, we used an ANOVA on ranks (with Dunn's method as post hoc test). In summary, C. bombycina consistently employs gait patterns with at least three legs in the air, i.e. To survive, the ants must keep their bodies below a critical temperature of 53.6C. 4AD), particularly in cases where no significant differences were observed between leg pairs. They do this to a larger extent than C. fortis, a fact that was further demonstrated by measuring stride amplitude. A weekly digest of Monitor views and insightful commentary on major events. 6 legend; Fig. Phase plots show the onsets of swing (Fig. For discrimination, ants were marked individually with car paint (Motip Lackstift Acryl, MOTIP DUPLI GmbH, Hamersheim, Germany). The silver ants leave their nest and forage for about 10 minutes when predatory ant lizards retire to the shade, usually under full midday sun, when sand temperatures reach some 70 C. In C. fortis, these transitions occurred at much higher speeds, at about 170mms1 for front and hind legs, and at a remarkable speed of about 370mms1 for the middle legs. The relatively short legs may thus contribute to C. bombycina reaching a 40Hz stride frequency, while the longer-legged C. fortis achieves just about 30Hz. Intriguingly, COM movement can be described by a steady walking path with no apparent variation in speed or acceleration in the rhythm of the step cycle, either for longitudinal or for transverse horizontal COM movements (see Figs S4 and S5). Stride length was calculated for each leg as the distance between lift-off and touch-down positions on the ground (SL in Fig. ; Project administration: M.W.

High-speed videos of Cataglyphis bombycina and Cataglyphis fortis locomotion are available from ResearchGate: doi:10.13140/RG.2.2.21093.45282 and doi:10.13140/RG.2.2.12704.84488. One reason why silver ants may have evolved their peculiar locomotor behaviour is the Saharan dune habitat, as opposed to the hard-baked clay in salt pans habitat of C. fortis. (A,C) Sample podograms (top) recorded in C. bombycina (A) and C. fortis (C) at similar walking speeds (about 350360mms1), and the corresponding colour (middle) and number indices (bottom) plotted along the same time axis. Known as thermophilic scavengers, these ants collect corpses of other insects [mostly flies] that have succumbed to the heat stress, says Rdiger Wehner, a professor at the Brain Research Institute at the University of Zrich, Switzerland, whos been studying heat-tolerant ant species for nearly four decades. These values were higher than TCS values recorded in C. fortis, especially at slow walking speeds. 4B) increased following a power function, although with different slopes in the two species (power functions for C. bombycina: y=1.43x0.52; C. fortis: y=0.81x0.59). If you have questions about your account, please For morphometric analyses (Fig. Channel walls were painted with matt grey varnish to avoid distracting reflections. At ant height, the air temperature can be 27F lower than the sizzling sand, he says. 2) are reflected in the smaller maximum stride amplitude. 5C,D graphs intersecting 0.5duty factor line). This is achieved by overlapping swing movements of the two tripod groups, partly as a result of the high synchrony of the leg movements within a tripod. Although clear tripod coordination was obvious in both ant species, there were small differences regarding the relative timing of the different legs within the step cycle. But theyre much smaller than mid-infrared wavelengths of light, which means they form a dull surface that can glow and emit light instead of reflecting it. In C. bombycina, TCS values were remarkably constant across the whole walking speed range. We Take our geography quiz. (The researchers still arent sure what role the corrugation on the two sides of each hair plays.). The middle legs were lifted together with the front and hind legs of their tripod group, but they started the transition towards stance phase slightly earlier (1.7ms) than the front and hind legs. With increasing walking speed, duty factor decreased in all three leg pairs, although in a somewhat different manner in the two ant species (Fig. ; Data curation: V.L.W. Bob is a news reporter for Science in Portland, Oregon,covering chemistry, materials science, and energy stories. The shorter legs, and resulting smaller stride lengths, of C. bombycina appear to be compensated for in this way.

A striking characteristic of the silver ant's locomotion is the high synchrony of the step cycles in the legs within a tripod group. ; Supervision: M.W., H.W. Cameraless photography creates lockdown 'supernovae' at home, Top 10 search results from Google and Bing differ by up to 75 per cent, Astronomers are mapping millions of hidden galaxies, We don't actually know what 'growing pains' are, How lab-grown 'mini-brains' could help prevent motor neurone disease, Watch the moment bison were released into the UK, Rock pool science with marine biologist Helen Scales, James Webb Space Telescope images reveal dazzling view of the universe, Images of extinct species highlight culprits of biodiversity loss, Fast way of making pufferfishs neurotoxin may lead to new pain drugs. Thank you for helping us continue making science fun for everyone. Wolfgang Mader deserves sincere thanks for his help with statistical evaluations, and Alexander Lindt and Andrea Kubitz for their support in animal care. The insects live in one of the hottest deserts on Earth, where temperatures on the surface of the desert sands can reach 70C. If you were to come up with a punchline to a joke about the Monitor, that would probably be it. you are agreeing to our, One month free trial to theMonitorDaily, Courtesy of Norman Nan Shi and Nanfang Yu, Are you scientifically literate? subscription. Leg lengths in C. bombycina were even smaller compared with those of C. fortis. A steeper decline of stance phase duration compared with swing phase duration with increasing walking speed is commonly observed in walking animals (e.g. Created by Bluecadet. Journal reference: Science, DOI: 10.1126/science.aab3564, JWST has found the oldest galaxy we have ever seen in the universe, Coronavirus may enter the brain by building tiny tunnels from the nose, No link between depression and serotonin, finds major analysis, Stunning JWST image turns dust in a distant galaxy into a purple swirl, What lab-grown 'mini-brains' are revealing about this mysterious organ. Video recordings were made by mounting the camera above the channel, providing a top view of the walking animals (see Fig. 4EH; stride amplitude, swing speed and angular velocity). Call it the ultimate sunshade. The reversal point, with phase durations being about equal, was at a walking speed of about 100mms1 in C. bombycina and about 180mms1 in C. fortis. And Im going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in. The researchers then used spectrometers to measure light reflection in ant specimens with their hairs intact, as well as specimens whose hair had been removed. 5C,D). Walking behaviour of C. bombycina (Fig. And the ants have another trick up their sleeve: they are hairy on their top and sides, but not underneath, where their hair would be detrimental as it would absorb the infrared radiation from the hot sand that it normally emits towards the cooler sky. A typical low-speed walking pattern is pentapod coordination, also termed wave gait, with one leg in swing and five legs on the ground. Different from stride length, stride amplitude was defined as the distance covered by a swing movement of the leg in body coordinates (Wosnitza et al., 2013). Maybe one day you will have a fur coat with silver hairs, muses Wehner. 6A shows an example of a podogram and corresponding gait indexing for C. bombycina; Fig. For example, in a given video frame, L1, R2, L3 may be in swing phase, and R1, L2, R3 in stance phase. Saharan silver ants have hair that both reflects and refracts sunlight, say scientists, to withstand temperatures over 120 F. For humans, silver hair can add a touch of sophistication. For pairwise comparisons of normally distributed data, we used the t-test; for non-normally distributed data, we used the MannWhitney U-test (U-test). Stride amplitude increased linearly with walking speed, from 2.5mm at 73mms1 to 8mm at 742mms1 in C. bombycina, and from 2.0mm at 74mms1 to 10.4mm at 433mms1 in C. fortis. Considering the TCS values reported above, it was not surprising to observe a clear anti-phase relationship between the two tripod groups, L1, R2, L3 and R1, L2, R3. The deviation of the petiole from this regression line was measured in the middle frame. Extra-long legs keep their bodies as far as possible from the hot sand, and special heat shock proteins allow them to withstand temperatures up to 128 degrees F. But these adaptations can only do so much any more than 10 minutes in the sun means certain death for the silver ant, so they must hunt quickly, sprinting 70 times their body length every second. For a quantitative analysis, each frame of the video was assigned an index number and a colour code marking the leg coordination in the particular video frame (see Fig. Can noxious beetle bursts make better engines? Ting et al., 1994). The shorter leg lengths of C. bombycina (cf. But they must be swift the ants die if their body temperatures climbs above 53.6 C. Hear about special editorial projects, new product information, and upcoming events. That reflection also lends the hairs their metallic sheen. Podograms illustrate the footfall patterns of the six legs; black bars indicate swing and white bars indicate stance phases (L, left; R, right body side; 1, 2 and 3, front, middle and hind legs). Scaling stride frequency and gait to animal size: mice to horses, Belknap Press of Harvard University Press, Flightlessness and rapid terrestrial locomotion in tiger beetles of the Cicindela L. subgenus Rivacindela van Nidek from saline habitats of Australia (Coleoptera: Cicindelidae), Cataglyphis desert ants: a good model for evolutionary biology in Darwins anniversary year - a review, Sensitive dependence of the motion of a legged robot on granular media, Ventilation and respiratory metabolism in the thermophilic desert ant, Cataglyphis bicolor (Hymenoptera, Formicidae), Quantification of gait parameters in freely walking wild type and sensory deprived Drosophila melanogaster, How to find home backwards? The ant looks like a ball of mercury rolling on the ground, cause theyre really glittering, says Wehner. We want to bridge divides to reach everyone.

tripod, bipod, monopod or aerial phases, across most of its walking speed range. Its very interesting to see that the same mechanism [engineered] by humans is also used by animals to deal with harsh weather.. Its kind of remarkable and pretty cool no pun intended that theres an analogue in nature to the way were thinking about these problems, Raman says. Thus, only at the highest speeds was the gait pattern composition similar to that of C. bombycina. The ants walked through a linear aluminium channel with a width of 7cm and a wall height of 7cm. For comparative purposes, the same procedures were followed for C. fortis (n=305 runs) (Fig. A weekly update on music, movies, cultural trends, and education solutions. New York, NY 10004. 6A,C). The team is also interested in applying what theyve learned about the silver hairs to developing optical coatings that could be used to passively cool down objects and materials. Cataglyphisfortis is a thermophilic scavenger (Wehner, 2016), much like C. bombycina, although it lives in North African salt pan habitats that typically exhibit baked salty clay substrates in the summer months, as opposed to the sand dune habitat of C. bombycina. Select stories from the Monitor that empower and uplift. Mendes et al., 2013; Pfeffer and Wittlinger, 2016). Please make a tax-deductible gift today. For indoor illumination, fibre optic cold light sources (Schott KL 1500LCD, 150W, Schott AG, Mainz, Germany) were used, while outdoor conditions in Tunisia provided sufficient light for video recordings. Martha Muoz is an Assistant Professor at Yale University, investigating the evolutionary biology of anole lizards and lungless salamanders. far lower than in C. fortis, where aerial phases occur at about 370mms1 and above. Silver ants make the most of this phenomenon by getting highthat is, moving to elevations on top of stones or vegetation where the air is even cooler, and heat can be transferred more effectively. Although these ants are known for their distinctive shiny coat, it was unclear before now whether the hairs played a role in temperature regulation. 5A) and clearly revealed in phase plot analyses (Fig. To emphasize and explicate particularities of the silver ants' locomotion, we compared their walking behaviour with that of another fast (though not quite as fast) running desert ant species, C. fortis. The length of the mean phase vector indicates the variance of data points. Ursula Seifert helped with editing and correcting the English in the manuscript. 6D). Calculating relative walking speed, typically in body lengths per second, appears more adequate when analysing parameters related to body size such as stride length or stride amplitude. We change lives. The petiole can be regarded as the centre of mass (COM) of an ant (see Reinhardt and Blickhan, 2014). It seems that these proteins accumulate prior to heat exposure, enabling C. bombycina to tolerate a critical thermal maximum of a body temperature of 53.60.8C (Gehring and Wehner, 1995). On desert sands they remind him of a droplet of mercury, he says. Both aspects were observed in the present comparison of ant species. Your tax-deductible contribution plays a critical role in sustaining this effort. The unique triangular hairs radiate heat away (Image: Norman Nan Shi and Nanfang Yu, Columbia Engineering). In their Review, Ateah Alfakih, Penelope Watt and Nicola Nadeau discuss the energetic cost of colour change and highlight how this can be avoided or lessened in animals that change colour rapidly or slowly. For example, when you get out of the bath in the morning, you feel cold.

It thus indicates by how much a leg's swing movement exceeds the respective body movement during the swing. In other words, the hairs arent just for style. Most morphological data for C. fortis were kindly provided by S. Sommer and R. Wehner. This is illustrated by the rather constant TCS values of around 0.8 (Fig. 1C) was recorded near Douz, Tunisia (33.44N, 9.04S), and at Ulm University, Germany (48.42N, 9.95S), under laboratory conditions. (B) The spread of footprints was quantified by calculating standard deviations the of footprint clusters shown in A. Footprint positions show similar spreads in C. bombycina and C. fortis [Levene's-test, Fvalue AEP=1.3<1.5 (critical value) and F-value PEP=1.4<1.5 (critical value)]. S2A,B). 6 legend). For morphometric measurements, both ant species were obtained from colonies in their natural habitats. But for one species of desert ant, it means the difference between life and death. Delays in homing may have serious consequences, making an excellent navigation ability and fast and efficient locomotion for straight and rapid homing important survival skills. Forward velocity (walking speed along the longitudinal axis) was calculated by measuring the distance between the petiole images in two consecutive video frames, and dividing that distance by 1ms, the frame rate. 2022 The Company of Biologists. But at mid-infrared wavelengths, those same hairs allow excess heat to be re-emitted in a process called black body radiation effectively cooling the ants by radiating away heat. These high frequencies are achieved by very short stance phases and fast swing speeds. This is mainly achieved by a combination of short stance phases (down to 7ms) and fast leg swing movements (up to 1400mms1). honey ant pot desert

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