Ant mimicry

Animals that resemble ants

Ant mimicry or myrmecomorphy is mimicry of ants by other organisms; it has evolved over 70 times. Ants are abundant all over the world, and potential predators that rely on vision to identify their prey, such as birds and wasps, normally avoid them, because they are either unpalatable or aggressive. Some arthropods mimic ants to escape predation (Batesian mimicry), while some predators of ants, especially spiders, mimic them anatomically and behaviourally in aggressive mimicry. Ant mimicry has existed almost as long as ants themselves; the earliest ant mimics in the fossil record appear in the mid Cretaceous alongside the earliest ants. In myrmecophily, mimic and model live commensally together; in the case of ants, the mimic is an inquiline in the ants' nest. Such mimics may in addition be Batesian or aggressive mimics. To overcome ants' powerful defences, mimics may imitate ants chemically with ant like pheromones, visually, or by imitating an ant's surface microstructure to defeat the ants' tactile inspections.

[[File:Ant mimic predatory bug, Myrmecoris gracilis, dorsal view, on Ragwort (cropped). JPG|thumb|Thick waist of the Mirid ant bug, Myrmecoris gracilis is camouflaged with white markings. The mimicry can be extremely close: for instance, Dipteran flies in the genus Syringogaster, "strikingly" resemble Pseudomyrmex and are hard even for experts to distinguish "until they take flight". Insects that do not share the narrow waisted body plan of ants are sometimes elaborately camouflaged to improve their resemblance. For example, the thick waist of the Mirid ant bug Myrmecoris gracilis has white markings at the front of its abdomen and the back of its thorax, making it look ant waisted. Over 300 spider species mimic the social behaviours, morphological features and predatory behaviour of ants. Many genera of jumping spiders (Salticidae) mimic ants. Jumping spiders in the genus Myrmarachne are Batesian mimics which resemble the morphological and behavioural properties of ants to near perfection. These spiders mimic the behavioural features of ants such as adopting their zig zag locomotion pattern. Further, they create an antennal illusion by waving their first or second pair of legs in the air. The slender bodies of these spiders make them more agile, allowing them to easily escape from predators. Studies on this genus have revealed that the major selection force is the avoidance of ants by predators such as spider wasps and other larger jumping spiders. Ant mimicry has a cost, given the body plan of spiders: the body of spider myrmecomorphs is much narrower than non mimics, reducing the number of eggs per eggsac, compared to non mimetic spiders of similar size. They seem to compensate by laying more eggsacs over their lifetimes. Batesian mimicry of ants appears to have evolved even in certain plants, as a visual anti herbivory strategy. Passiflora flowers of at least 22 species, such as P. incarnata, have dark dots and stripes on their flowers for this purpose.

Aggressive mimics are predators which resemble ants sufficiently to be able to approach their prey successfully. Some spiders, such as the Zodariidae and those in the genus Myrmarachne, Among the many spiders which are aggressive mimics of ants, Aphantochilus rogersi mimics its sole prey, Cephalotini ants. Like many other ant mimicking spiders, it is also a Batesian mimic, gaining protection from predators such as spider hunting wasps.

Multiple groups of insects have evolved ant mimicry for their young, while their adults are protected in different ways, either being camouflaged or have conspicuous warning coloration. and Tarachodes afzelii are Batesian mimics of ants. Bigger instars and adults of these mantids are not ant mimics, but are well camouflaged predators, and in the case of Tarachodes, that eat ants. Young instars of some bush crickets in the genus Macroxiphus, have an "uncanny resemblance" to ants, extending to their black coloration, remarkably perfect antlike shape, and convincingly antlike behaviour. Their long antennae are camouflaged to appear short, being black only at the base, and they are vibrated like ant antennae. Larger instars suddenly change into typical looking katydids, and are entirely nocturnal, while the adult has bright warning coloration.