Despite a common misconception, most ants lack painful bites being too small to have any effect on human skin. Usually ant "bites" are actually the venomous stings of ants in certain subfamilies most commonly the Myrmicinae, but also members of the Ponerinae , Myrmeciinae , Pseudomyrmecinae , and others, and perhaps most notoriously the bullet ant, Paraponera clavata.
Perhaps more important generally is the role of mandibles in defense against smaller predators and competitors, such as other ants. Many ants have a major worker caste "soldiers" with large body size and massive mandibles e. Eciton and Pheidole , described below. Such major workers can be truly formidable adversaries to their opponents. Some ants have evolved mandibles specialized for offense against other ants, including Polyergus , a genus of slave-making ants which uses its sickle-like mandibles to maim or kill Formica workers defending their brood see below.
The basic mouthparts of insects include from anterior to posterior the labrum upper lip , paired mandibles, paired maxillae, and the labium lower lip Chapman, Both the maxillae and labium have sensory palps; the number of palp articles "segments" are important characters in the identification of ant genera. The primitive condition in ants is believed to be 6-segmented maxillary palps and 4-segmented labial palps written "6, 4" , but this number has frequently become reduced during the evolution of various ant lineages Bolton, In addition, in some ants e.
Myrmecocystus certain palp articles have become greatly elongated. Like all pterygote insects, ant mandibles have two points of articulation with the head such mandibles are termed "dicondylic" and are thus constrained to move transversely Triplehorn and Johnson, A typical ant mandible is illustrated in Fig.
It is characterized by an outer, external margin Fig. From the masticatory margin arise a variable number of teeth and denticles Fig. Figure 1. Mandible of Hagensia havilandi Ponerinae; South Africa , illustrating the basic external morphology of an ant mandible points of articulation with the head not shown. Note the long transverse groove extending much of the length of the mandible; similar grooves and pits occur on the mandibles of many ants.
Note also the row of setae along the masticatory border, another common feature of ant mandibles. Image copyright Chris A. Ants primitively had short, curved mandibles with two teeth apical and pre-apical Bolton, While many modern ants have basically this same mandibular morphology although usually with additional teeth , a more typical groundplan is for the mandible to have an elongated masticatory margin and a prominent basal angle, giving the mandible a distinctive triangular shape.
These are also found in silver fish, termites, earwigs, beetles, some hymenopterans and in caterpillars of Lepidoptera.
This type of mouth parts are modified for collecting the nectar and pollen from flowers and also for moulding the wax, as is found in honeybees, wasps, etc. They consist of the labrum, epipharynx, mandibles, first pair of maxillae and second pair of maxillae. The labrum lies below the clypeus, below the labrum is a fleshy epipharynx which is an organ of taste. Mandibles are short, smooth and spatulated, situated one on either side of the labrum; used in moulding wax and making the honeycomb.
The labium second pair of maxillae has reduced paraglossae, the glossae are united and elongated to form the so called retractile tongue, at its tip is a small labellum or honey spoon.
The labial palps are elongated. The glossa is used for gathering honey and it is an organ of touch and taste. The first pair of maxillae are placed at the sides of labium, they bear small maxillary palps, lacinia is very much reduced but galea are elongated and blade-like.
The galea and labial palps form a tube enclosing the glossae which moves up and down to collect nectar from flower nectaries. The nectar is sucked up through the tube, so formed, by the pumping action of the pharynx. The labrum and mandibles help in chewing the food. This type of mouth parts are adapted for piercing the tissues of animals and plants to suck blood and plant juice, and found in dipteran insects like mosquitoes and hemipteran insects like bugs, aphids, etc.
They usually consist of labium, labrum and epipharynx, mandibles, maxillae 1st pair and hypo pharynx. However, for the sake of easy description, this type of mouth parts can be discussed in the following two headings:.
The labium is modified to form a long, straight, fleshy tube, called proboscis. It has a deep labial groove on its upper side.
The labial palps are modified to form two conical lobes at the tip of the proboscis, called labella which bear tactile bristles. The labrum is long needle-like. The epipharynx is fused with the labrum. The labrum-epipharynx, thus, covers the labial groove dorsally from inside. These structures appear C- shaped in transverse section having a groove, called food channel. Mandibles, maxillae and hypo pharynx are modified to form needle-like stylets which are placed in the labial groove.
In male mosquitoes, the mandibles are absent. The mandibles are finer than the maxillae, but both have saw-like edges on their tips. Piercing sucking mouthparts on a plant feeding bug. Why is this important? Knowing the type of mouthparts is important to entomologists because mouth design provides a clue to the ancestry or taxonomy of the insect. We use mouthparts as a clue, for example, to know which basic insect group Order an insect belongs to.
Major insect groups that have chewing mouthparts include the cockroaches and grasshoppers, most wasps, beetles, termites and caterpillars. Insects with piercing-sucking mouthparts include some flies think mosquitoes , fleas, true bugs and their relatives. Another time it is useful to know something about insect mouthparts is when trying to diagnose plant damage.
The metal appears to be incorporated within the biological matrix, possibly bonding with proteins. However, the comparative advantage of metal inclusion has not been tested. This question has direct bearing on the significance of metal hardening. In the present article, we compare across mandibles from six termite species, including samples with major zinc concentration, minor manganese, and no metals.
Nanoindentation, electron microscopy, and electron microanalysis are used to assess metal concentration, form, and mechanical properties. The data demonstrate that termite mandibles lacking metals when fully developed have lower values for hardness and elastic modulus. The similar transition metal, manganese, found in minor concentrations, is not linked to any significant increase in these mechanical properties.
This raises the question of the function of manganese, which is as commonly found in insect mandibles as zinc and often located in the same mandibles. This is a preview of subscription content, access via your institution.
Rent this article via DeepDyve. ChemBioChem — Arthropod Struct Dev — Cell Biol Int — Article Google Scholar. J Entomol Soc Brit Columbia — Google Scholar.
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