How can ants climb walls

Pharaoh Ants: Pharaoh ants build their nests in moist areas like kitchens and bathrooms near water sources, inner wall voids, beneath floors, under baseboards, and window sills, and feed on proteins and sugars. Indoor Ants : Indoors, tiny black ants may build nests in voids in walls, cabinets, and brick or stone veneer.

Citronella Ants: Citronella ants are winged ants that swarm indoors from cracks and crevices in floors and walls, as well as the basement and foundation: they feed on honeydew from aphids and mealy bugs living underground. In recent decades, studies of how insects walk on walls and ceilings have led to technological advances. Spinybot used lots of tiny spiky hairs, replicated from hairy adhesion pads of cockroaches, to create a wall-climbing robot that has applications in military and police operations.

Ants climb walls thanks to their liquid-producing pads that act like suction caps. When the liquid is excreted they get extra sticky. They use their claws to grip walls and detach their suction caps. Furthermore, Hairs on their feet and ankles help to sustain grip.

With a combination of these three biological capabilities, ants can walk on walls and ceilings. They can walk on glass, plastic, metal, and nearly every other surface. To prevent them from climbing, you either need to use a PTFE substance of spray the wall with an insect repellant surface spray.

I am the founder and owner of Fauna Facts. My mission is to write valuable and entertaining information about animals and pets for my audience. I hope you enjoy the site! Skip to content Ants climb walls using a combination of three features: claws, suction pads, and grippy hairs on their feet.

What You Will Learn show. The 3 Ways Ants Climb Walls 1. Claws for Grip. Hairs on Feet. How to Stop Ants from Climbing Walls. Curated, kid-friendly, independently-published.

Support this mission by becoming a sustaining member today. Get smart curated videos delivered to your inbox. Twitter Instagram. Primary Menu. Search for: Search. In addition to the recordings of ants climbing on a vertical surface, we filmed ants walking on horizontal and inverted glass surfaces without force measurement.

Force and video recordings were analysed frame by frame using custom-built Matlab scripts. Data were filtered using a 2 nd order Butterworth low-pass filter with a cut-off frequency of 20 Hz. From the smoothed data, we measured peak forces in both axes, as well as the contact area and 5 th tarsomere angle with the surface at the same time. When data are presented as box-plots, the median is shown by a line, and the 25 th and 75 th percentiles by the box. The whiskers extend to the most extreme data values that are not outliers values exceeding the 25 th or 75 th percentile by 1.

Throughout the paper, we use means for normally distributed data, and medians otherwise. In order to test friction forces of the hairy tarsomeres in a controlled way on different surfaces and in different directions, we used severed legs of freshly killed ants. The leg was mounted on a microscope slide such that the ventral side of the 3 rd and 4 th tarsomere formed the highest point and could be brought into contact with the surface of the force transducer. The 2D-force transducer was moved by a motorised XZ-stage.

Pads were first brought into contact with the surface allowing five seconds to adjust to the preload, followed by a pull and then a push. We further tested the effect of surface roughness by using either a smooth glass cover slip 0.

When weaver ants walked on a horizontal substrate average speed However, no evidence of a contact area was found in the recordings of the surface of the platform. This indicates that the claw flexor muscle controlling not only the claws, but also the last tarsomere and the adhesive pad [ 18 ] was mostly relaxed and the tarsomeres were in their raised default position.

A Level walking. B Inverted climbing. Here, the 5 th tarsomere angle of was mostly positive, allowing the adhesive pad arolium to make contact see also photo. In contrast, when ants walked on an inverted substrate average speed In these cases, ants possibly relied on their front and middle legs to adhere to the substrate.

When climbing on a vertical surface average speed On average, legs above the CoM produced negative normal forces of 0. A normal forces. The ants held their body weight mainly by pulling with legs above the CoM median 0.

Some legs below the CoM contributed to upward forces by pushing maxima up to 0. Some legs mainly hind legs produced forces opposite to those of the legs above the CoM, effectively pulling the ant downward during upward climbing negative values in Fig 3B and upward during downward climbing positive values in Fig 3B.

The largest anti-gravity forces were developed by legs that were pointing upward above the body CoM , whereas smaller anti-gravity forces or even downward pulls occurred in downward-pointing legs below the body CoM. For all legs with negative angles, the foot position was below the CoM, and positive angles corresponded to foot positions above the CoM.

We compared ground reaction forces produced by legs that used the adhesive pad with those that did not. In steps with adhesive pads the normal forces were mostly negative adhesive and the legs pulled toward the body lower left quadrant in Fig 5. In contrast, when the adhesive pad was not used, the legs mostly pressed onto the substrate positive normal forces and were used in a pushing direction upper right quadrant in Fig 5. This is in line with previous findings that force vectors are usually aligned approximately with the legs to minimize joint torques, and that pushing leads to a detachment of the arolium [ 3 ].

Only a few cases showed legs pulling and pressing lightly into the surface mostly with the arolium in contact, upper left quadrant in Fig 5. We never recorded any steps where the legs pushed and produced a negative normal force. Minimal adhesion during a push is probably critical for effortless and rapid detachment during locomotion, and may be a very widespread property of animal adhesive structures [ 19 ].

Filled circles denote steps in which the arolium made visible surface contact, whereas steps with detached arolium are marked with open circles. Lines show standardised major axis regressions on both types of steps. In most steps where the adhesive pad made contact, the legs were pulling, whereas steps without visible arolium contact occurred mostly when legs pushed.

The drawings illustrate the direction of the normal forces F N and shear forces F S and the presence or absence of adhesive pad contact black or white filling of the pad. Both in the pushing and the pulling direction, there was an approximately linear relationship between peak normal forces and the corresponding shear forces, with a small intercept. This indicates a relatively constant angle between the force vector and the substrate.

When ants made steps without using the adhesive pad, the ventral side of the 4 th tarsomere, and sometimes of the 3 rd tarsomere, touched the surface. These tarsomeres are covered in fine pointed hairs that are oriented distally Fig 6A. The density of the hairs was approx. The pointed tips appear to be slightly flattened see Fig 6A , high magnification.

A Morphology of hairs on the underside of the tarsus. On the smooth surface, the friction forces generated by the tarsal hairs amounted to 3. The values correspond to a load-dependent effective friction coefficient ranging from 4. The dashed lines show the results of a linear regression on the median for each normal force level. Adhesive forces of the hair arrays were much smaller than friction forces on both substrates Fig 8. The contact area recordings revealed that the hairs buckled when subjected to a high enough shear force in the pushing direction Fig 9 ; see also S1 Video.

When buckling, the hairs re-orientated into the proximal direction and the contact area again increased. A SEM image showing the tarsal hairs of the 3 rd and 4 th tarsomeres the part in contact with the surface is outlined with a dashed line.

B Contact area of the hairs in pulling orientation using coaxial illumination on a stereo-microscope. C Hairs at the point of buckling. D Hairs re-orientated under pushing shear forces. E Force trace of tarsal hairs under different preloads and shearing directions on smooth and rough surfaces. Images in sub-figures B-D were taken at the points marked with squares in the raw trace curve.

Darker shaded regions indicate the time period during which the motorised stage moved the sample in the pushing direction. While on the smooth surface, the buckling force was smaller than the maximum friction, the kink in the force trace was less well-defined on the rough surface and no direct visualization of the contact zone was possible.

Nevertheless, it is likely that buckling on the rough surface occurred at a similar time after the start of the pushing movement Fig 9 , but the forces during steady-state pushing did not rise higher than the buckling force. As the surface contact of the tarsal hairs was often not clearly visible with the stereo microscope available during the force measurements, we used reflected-light microscopy with a x oil immersion objective to obtain higher resolution images.

The contacts were up to The total area covered was approx. A side contact of the hairs B tiny droplets left on the surface after pull-off. When the tarsomeres were moved toward the surface, equivalent to an increase in normal force, the length of the side contacts increased see S2 Video in the Supporting Information section. The length of individual hair contacts also increased when sheared in the pulling direction.

Similar to adhesive pads, pulling off the tarsal hairs left behind tiny footprint droplets Fig 10B. Our results show that weaver ants use different parts of their foot in different climbing situations. When walking upside down on a smooth surface, they used only their adhesive pads. When walking upright, they mostly kept their pads off the substrate and stood on their 3 rd and 4 th tarsal segments.

When climbing vertically, they engaged the adhesive pads for legs above the CoM, but mainly the 3 rd and 4 th tarsal segments for legs below the CoM. The much larger contribution to vertical forces by legs above the body CoM compared to legs below the CoM differs from previous results for cockroaches climbing on rough substrates, where forces were found to be relatively equally distributed between legs [ 20 ].

The pushing hind limbs may release constraints for the fore limbs which are in pulling orientation. A similar division of labour between proximal and distal parts of the tarsus for walking on horizontal, inverted and vertical surfaces has been found in other insect orders cockroaches [ 21 ], Mantophasmatodea [ 22 ] and stick insects [ 13 ].

As a result of the sprawled posture, the feet of an insect walking on the ceiling experience not only negative normal forces acting on the feet but also an inward pull. This inward pull may also be significant during vertical climbing, in particular for the two laterally oriented middle legs which produce lateral horizontal forces by pulling against one another.

Although the lateral forces usually cancel out, this inward pull is very important as it helps to reduce the angle of the force vector with the substrate, thereby increasing adhesion as predicted by peeling theory [ 23 , 24 ]. The increased adhesion via inward pulls may also explain why hind legs in ascending ants often pulled the ant down , even increasing the shear forces for the front legs.

Similarly, the legs of insects walking upright are not only pressing into the substrate but also pushing outward. In all insects studied, negative normal and pulling forces are resisted by distal adhesive pads, whereas pushing forces are produced by more proximal tarsal structures. For example, Clemente et al. While stick insect euplantulae lack such a direction-dependence, their contact is strongly dependent on normal load, thereby allowing them to generate high friction only when pressed onto the substrate [ 13 , 26 ].

Unlike cockroaches, mantophasmids and stick insects, ants lack specialised euplantulae, but their tarsal segments bear on the underside arrays of pointed hairs. Similar tarsal hairs are present in many other Hymenoptera [ 27 ], and these structures have thus far not been recognized as adhesive or frictional structures, nor have their properties been investigated.

Within the range of normal loads tested, shear forces increased approximately linearly. The increase in friction forces can be explained by the tendency of the tarsal hairs to make side contact.