Academic literature on the topic 'Ant-mimicry'

Ant mimicry, i.e., the mimicking of ant workers by another organism, is a widespread phenomenon among different groups of Euarthropoda, including spiders and different insect species. One example of ant mimicry occurs among praying mantises (Mantodea); here the first stage nymphs have been recorded to perform ant mimicry. In this study, we investigated different nymphal instars of Miomantis binotata for possible morphological similarities to ants. The different instars were compared as stages supposed to perform ant mimicry would differ morphologically from those stages not supposed to resemble ants. The specimens were investigated under different microscopic settings and measurements were performed. Our results do not show significant differences concerning morphological measurements or shape of structures between the different nymphal instars of M. binotata. One prominent difference between stage one nymphs and later stages occurs in the colouration of the body, which is very dark in the earliest nymph. This difference might explain why young nymphs of Miomantis binotata are interpreted as ant-mimicking, despite the apparent lack of other morphological resemblances.

Mimicry is a fascinating topic, in particular when viewed in terms of selective forces and evolutionary strategies. Mimicry is a system involving a signaller, a signal receiver, and a model and has evolved independently many times in plants and animals. There are several ways of classifying mimicry based on the interactions and cost-benefit scenarios of the parties involved. In this review, I briefly outline the dynamics of the most common types of mimicry to then apply it to some of the spider-ant associative systems known to date. In addition, this review expands on the strategies that ant-associating (in particular ant-mimicking) spiders have developed to minimise the costs of living close to colonies of potentially dangerous models. The main strategy that has been noted to date is either chemical mimicry or actively avoiding contact with ants. If these strategies warrant protection for the spider (living close to potentially dangerous models), then the benefits of ant associations would outweigh the costs, and the association will prevail.

Myrmecotypus tahyinandu sp. n. is described from the Bolivian Chiquitano forest, and M. niger Chickering, 1937 is recorded from Bolivia for the first time. The morphological differentiation among the closely related M. tahyinandu sp. n. and M. iguazu Rubio & Arbino, 2009 is likely attributable to the selection for specific ant mimicry. Adults of M. tahyinandu sp. n. are accurate mimics of the ant Camponotus crassus Mayr, 1862, M. iguazu of C. sericeiventris (Guérin-Méneville, 1838), and M. niger of Dolichoderus bispinosus (Olivier, 1792). This study is the first to identify ant models for morphologically closely related Castianeirinae, providing a promising starting point for future research on ant mimicry.

Protective mimicry, in which a palatable species avoids predation by being mistaken for an unpalatable model, is a remarkable example of adaptive evolution. These complex interactions between mimics, models and predators can explain similarities between organisms beyond the often-mechanistic constraints typically invoked in studies of convergent evolution. However, quantitative studies of protective mimicry typically focus on static traits (e.g. colour and shape) rather than on dynamic traits like locomotion. Here, we use high-speed cameras and behavioural experiments to investigate the role of locomotor behaviour in mimicry by the ant-mimicking jumping spider Myrmarachne formicaria , comparing its movement to that of ants and non-mimicking spiders. Contrary to previous suggestions, we find mimics walk using all eight legs, raising their forelegs like ant antennae only when stationary. Mimics exhibited winding trajectories (typical wavelength = 5–10 body lengths), which resemble the winding patterns of ants specifically engaged in pheromone-trail following, although mimics walked on chemically inert surfaces. Mimics also make characteristically short (approx. 100 ms) pauses. Our analysis suggests that this makes mimics appear ant-like to observers with slow visual systems. Finally, behavioural experiments with predatory spiders yield results consistent with the protective mimicry hypothesis. These findings highlight the importance of dynamic behaviours and observer perception in mimicry.

Batesian and aggressive mimicry are united by deceit: Batesian mimics deceive predators and aggressive mimics deceive prey. This distinction is blurred by Myrmarachne melanotarsa , an ant-like jumping spider (Salticidae). Besides often preying on salticids, ants are well defended against most salticids that might target them as potential prey. Earlier studies have shown that salticids identify ants by their distinctive appearance and avoid them. They also avoid ant-like salticids from the genus Myrmarachne. Myrmarachne melanotarsa is an unusual species from this genus because it typically preys on the eggs and juveniles of ant-averse salticid species. The hypothesis considered here is that, for M. melanotarsa , the distinction between Batesian and aggressive mimicry is blurred. We tested this by placing female Menemerus sp. and their associated hatchling within visual range of M. melanotarsa , its model, and various non-ant-like arthropods. Menemerus is an ant-averse salticid species. When seeing ants or ant mimics, Menemerus females abandoned their broods more frequently than when seeing non-ant-like arthropods or in control tests (no arthropods visible), as predicted by our hypothesis that resembling ants functions as a predatory ploy.

Structural features and life habits of described species of the extinct †Alienoptera are evaluated based on previously published studies on the group. Head structures and feedings habits are addressed, as are the locomotor organs, especially the wings and adhesive devices. Suggested pollen feeding habits and the possible role as pollinators are discussed, as well as hypothesized ant and wasp mimicry and myrmecophily. Species of †Alienoptera were likely predators, in the case of †Caputoraptor elegans Bai, Beutel et Wipfler, 2018 with a unique cephalo-prothoracic prey grasping mechanism. They were likely strong fliers with anatomical dipterism with functional hind wings. Wing joints protected by scale-like sclerotized fore wings probably allowed them to move very efficiently in dense foliage of trees or shrubs and to prey upon smaller insects. Ant mimicry, myrmecophily and “weevil mimicry” are rejected. †Meilia Vršanský et Wang, 2018 is a possible case of wasp mimicry but more evidence is required. Other suggested cases of mimicking wasps are unfounded.

Understanding the evolutionary transition from interspecific exploitation to cooperation is a major challenge in evolutionary biology. Ant–aphid relationships represent an ideal system to this end because they encompass a coevolutionary continuum of interactions ranging from mutualism to antagonism. In this study, we report an unprecedented interaction along this continuum: aggressive mimicry in aphids. We show that two morphs clonally produced by the aphid Paracletus cimiciformis during its root-dwelling phase establish relationships with ants at opposite sides of the mutualism–antagonism continuum. Although one of these morphs exhibits the conventional trophobiotic (mutualistic) relationship with ants of the genus Tetramorium, aphids of the alternative morph are transported by the ants to their brood chamber and cared for as if they were true ant larvae. Gas chromatography-mass spectrometry analyses reveal that the innate cuticular hydrocarbon profile of the mimic morph resembles the profile of ant larvae more than that of the alternative, genetically identical nonmimic morph. Furthermore, we show that, once in the brood chamber, mimic aphids suck on ant larva hemolymph. These results not only add aphids to the limited list of arthropods known to biosynthesize the cuticular chemicals of their deceived hosts to exploit their resources but describe a remarkable case of plastic aggressive mimicry. The present work adds a previously unidentified dimension to the classical textbook paradigm of aphid–ant relationships by showcasing a complex system at the evolutionary interface between cooperation and exploitation.

Many spiders possess myrmecomorphy, and species of the jumping spider genus Myrmarachne exhibit nearly perfect ant mimicry. Most salticids are diurnal predators with unusually high visual acuity that prey on various arthropods, including conspecifics. In this study, we tested whether predation pressure from large jumping spiders is one possible driving force of perfect ant mimicry in jumping spiders. The results showed that small non-ant-mimicking jumping spiders were readily treated as prey by large ones (no matter whether heterospecific or conspecific) and suffered high attack and mortality rates. The size difference between small and large jumping spiders significantly affected the outcomes of predatory interactions between them: the smaller the juvenile jumping spiders, the higher the predation risk from large ones. The attack and mortality rates of ant-mimicking jumping spiders were significantly lower than those of non-ant-mimicking jumping spiders, indicating that a resemblance to ants could provide protection against salticid predation. However, results of multivariate behavioural analyses showed that the responses of large jumping spiders to ants and ant-mimicking salticids differed significantly. Results of this study indicate that predation pressure from large jumping spiders might be one selection force driving the evolution of nearly perfect myrmecomorphy in spiders and other arthropods.

The jumping spider genus Myrmarachne (Salticidae) contains many different morphological ant mimics that resemble a wide variety of ant species. This mimicry enables Myrmarachne to evade ant-averse predators that confuse the spiders with ants. A conspicuous trait of Myrmarachne, which is frequently mentioned in the literature but has been overlooked experimentally, is locomotory mimicry. In this thesis, I quantified, for the first time, the locomotory pattern of non-ant-like salticids, Myrmarachne, and their presumed models. Indeed, I found that the locomotion of the mimics resembles that of ants, but not of other salticids. I then attempted to identify whether this behavioural mimicry enhances the morphological component of the mimicry signal. The locomotion component was tested by modelling a 3D computer animation based on the morphology of Myrmarachne, and then applying either non-ant-like salticid motion characteristics or ant-like locomotion to the models. These animations were presented to ant-eating salticid predators, which are known to have acute vision, in order to identify any differences in how the predators reacted to each virtual prey type based solely on differences in locomotory behaviour. No significant effect was identified for enhancing the deception, but there was a non-significant trend that hinted at an enhancement of the mimicry signal, suggesting that a more robust finding would be found with a larger sample size. Additionally, ant mimics are unusual in their relationship to their model organism, as the ant models are also potential predators of the mimic. Predation by visual ant species may exert selection pressure on Myrmarachne across some aspects of morphological or behavioural mimicry. In turn, this may select for traits that improve Myrmarachne’s survival in close proximity to their highly aggressive models. Consequently, I investigated whether ant-like locomotion is salient to a visual ant species, Oecophylla smaragdina. I found that the locomotion typical of ants and Myrmarachne is more attractive to ants than non-ant-like salticid locomotion. This suggests that the trade-off of increased resemblance to ants is not just towards being categorised as prey by ant-eating species, but also by being more attractive to ant species. This may place them at greater risk of predation by the model. As a whole, these results suggest that there is selection pressure on Myrmarachne for increased resemblance to a model by locomotory mimicry, despite associated costs when faced with ant-eating predators and when living in proximity to models that are both aggressive and visual.

Mimicry in arthropods is seen as an example of evolution by natural selection through predation pressure. The aggressive nature of ants, and their possession of noxious chemicals, stings and strong mandibles make them unfavourable prey for many animals. The resemblance of a similar-sized arthropod to an ant can therefore also protect the mimic from predation. Myrmarachne is an ant-mimicking salticid spider genus, whose species associate closely with their model ant species. The behavioural reactions of Myrmarachne to ants were analysed, including instances when there was contact between the spider and the ant. In Townsville the salticid Cosmophasis bitaeniata and one Myrmarachne species associate with Oecophylla smaragdina workers. The Myrmarachne mimics the ant visually, and Cosmophasis bitaeniata mimics the cuticular hydrocarbons of the O. smaragdina worker ants. Cosmophasis and Myrmarachne also mimic ants through certain types of behaviour, such as the “antennal illusion” and bobbing the opisthosoma up and down. The behaviour of both salticids to O. smaragdina was compared. This Myrmarachne was also studied with a hemipteran mimic of O. smaragdina, Riptortus serripes, to see whether the salticid could discriminate between the potentially dangerous ant and its hemipteran mimic. The history of the evolutionary dynamics between Myrmarachne and the model ant species were studied by analysing molecular phylogenies of the two animal taxa. In a confined space, Myrmarachne species displayed versatile reactions to sympatric ants that depended on factors such as the position of the ant and the distance between the Myrmarachne and the ant. Myrmarachne also show interspecific differences in their reactions to ants. All Myrmarachne species avoided contact with the ants whenever possible. Even when there was contact between the two, Myrmarachne managed to avoid being attacked by the ant. Cosmophasis bitaeniata also avoids contact with ants. C. bitaeniata and Myrmarachne had the same reaction types to ants, but actions occurred at different frequencies. Overall, there were more similarities than differences between the ways these two salticids interacted with O. smaragdina worker ants, even though Myrmarachne and C. bitaeniata have different methods of mimicking the ants. As for the types of behavioural mimicry, there was a significant difference between Myrmarachne species, as well as between the two salticid genera. When Myrmarachne was presented with another morphological ant mimic (the alydiid bug Riptortus serripes), the spiders’ reactions differed from those displayed towards the ants. These differences indicate that Myrmarachne can distinguish the ant and the bug using visual cues (perhaps through the structure of the mouthparts, or the way the two insects move around). So behaviourally, Myrmarachne is a versatile genus apparently under strong selection pressure and showing a high rate of differentiation and speciation. The phylogenetic study also reflects strong selection pressure, resulting in highly polymorphic species. Myrmarachne species have undergone adaptive radiation and speciation as they evolved towards resembling their different model ant species. Therefore the behavioural and evolutionary dynamics of these salticids and their model ants represents a case of plasticity and versatility by the salticids.