The African weaver ant gets its name because of the way the ants use larval silk in order to "weave" leaves together to form their nests.
Oecophylla longinoda have developed at least 5 systems by which an individual ant can gather together a large group for the purpose of exploring new territory, attacking an enemy, or obtaining food. The first system of communication is used for the recruitment of ants to new terrain. For example, when weaver ants approach a gap in the ground, they will need to recruit other ants to help build a bridge with their bodies in order to cross the gap. A combination of chemical and tactile signals is used to recruit the other ants. The chemical signal is a secretion from one of two glands located near the anus. These secretions are laid down as a trail for the other ants to follow, which other ants then "smell" with their antennae.
The second system also recruits ants by means of an odor trail, but for the purpose of finding new food sources. Foraging communication includes odor trails, tactual stimuli functioning during mouth opening, antennation (moving the antennae), and head waggling.
The third type of communication leads to emigration to new sites. When ants encounter a new home range, they randomly place drops of fluid from the rectal vesicle. They can then distinguish their territory from a foreign colonies' by the odor of these spots.
The fourth system serves the purpose of short-range recruitment to defend against territorial intruders. This “alarm” pheromone is released when the terminal abdominal sternite is completely visible and hauled for a limited distance over surfaces to release an attractant from the sternal gland.
Finally, for long-range recruitment of defense against intruders, a combination of odor trails, as well as antennation and extreme "body jerking", are used.
Communication Channels: visual ; tactile ; chemical
Other Communication Modes: pheromones ; scent marks ; vibrations
Perception Channels: visual ; chemical
This species is in no danger and has no special status.
US Federal List: no special status
CITES: no special status
There are four stages to the life cycle of weaver ants: Egg; Larvae; Pupae; Adult. It takes approximately 30 days to develop from an egg into an adult worker. There are also at least three larval instars (larval growth periods) before the immature ant can pupate. O. longinoda pupates without enclosing itself in silk, as it spends its silk on nest construction. Instead, it remains exposed as it undergoes a complete metamorphosis from its larval, grub-like form into an adult ant.
Development - Life Cycle: metamorphosis
The African Weaver ant has no negative economic impact on humans.
Negative Impacts: injures humans (bites or stings)
African weaver ants can be used to protect cacao tree crops. The African weaver ant effectively controls certain species of Homoptera (an order of bugs), a common pest of the cacao. The mealy bug, one species of Homoptera, transmits Cacao Black Pod Disease as it moves from tree to tree feeding on the leaves. Utilizing African weaver ants to control populations of these insects can greatly reduce crop damages due to this disease.
Positive Impacts: controls pest population
The African weaver ants are primarily insectivorous, attacking and eating any ants or other insects that invade their nest. They will even attack and eat weaver ants from other colonies. Another main staple food for the weaver ant is the honeydew excrement from herds of scale insects colonies often maintain.
Animal Foods: body fluids
Primary Diet: carnivore (Insectivore )
The African weaver ant occupies the tropical rain forests of Sub-Saharan Africa.
Biogeographic Regions: ethiopian (Native )
Weaver ants are arboreal, living in heavily forested areas. The way in which weaver ants build their nests reduces spatial limitations to their colonies, and one colony may occupy several trees at one time.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest
Little is known about the lifespan of this species.
Oecophylla longinoda are relatively large ants, with the bodies of workers averaging 6 mm in length. The body of the ant is segmented and is divided into three main parts; the head, thorax, and abdomen. Like all insects, six legs are connected to the thoracic region. These ants range from orange to dark brown in color. Erect hairs cover the surface of the gaster while a finer pubescence encompasses the rest of its body. The eyes are well developed with eyespots. The clypeus, the large shield-like plate on the front of its head, is large and convex with the outer edges overhanging the basal borders of the mandibles. It has 12-segmented antennae with the first segment of the antennae longer than the second and the third put together. Its mandibles are extended, and have triangular elongated teeth that cross one another when at rest. The thorax is very constricted in the mesonotal region. The petiole between the thorax and abdomen is thin in dorsal view, but looks low and rounded in the side view. The gaster has a visible acidopore. On the ants' feet, there are powerful suction pads called arolia, allowing this ant to maintain heavier loads than other ants. Another important characteristic of the weaver ant is the presence of the rectal gland and the sternal gland, both of which are located near the anus and are used to secrete chemicals to recruit nestmates when circumstances arise that require the attention of a group of ants.
Average length: 6 mm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Certain species of caterpillars use chemical mimicry to enter nests and eat eggs and larvae, but little more is known of the predators of this species.
Mating System: eusocial
After her nuptual (copulatory) flight, the new queen will find a protected area on the outer regions of a tree. She chooses the outer regions probably because other queens may have chosen the same tree and the farther away they are from eachother the safer their brood are from the others' workers. The single queen is responsible for all the reproductive needs of the colony. She lays one hundred eggs per day, which are carried to brood piles to be cared for by the minor workers.
Average time to independence: 30 days.
Key Reproductive Features: iteroparous ; year-round breeding ; sexual ; fertilization (Internal ); oviparous ; sperm-storing ; delayed fertilization
Like all ants, the very first brood is cared for by the queen. She feeds the larvae regurgitated body fluids and unfertalized eggs, often losing up to 60% of her body weight in the process, as she will not leave her brood during this time to go out and forage. After the first workers develop, they take over brood care and the queen devotes the rest of her time and energy to egg laying. In addition to caring for eggs and larvae, workers care for the queen by feeding and cleaning her.
Although minor workers are the primary nursemaids, once the larvae reach their maximum size they are cared for equally by the major and minor workers.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female)
Extant: 7 valid subspecies
Formica longinoda Latreille, 1802a PDF: 184, pl. 11, fig. 72 (w.) SENEGAL. Afrotropic. AntCat AntWiki HOLTaxonomic history
Emery, 1892f PDF: 564 (q.); Forel, 1913b PDF: 339 (m.).Combination in Oecophylla: Mayr, 1863a PDF: 439.Junior synonym of Oecophylla virescens: Smith, 1858a PDF: 29.Subspecies of Oecophylla smaragdina: Emery, 1892f PDF: 564; Forel, 1907h PDF: 15; Santschi, 1914b PDF: 128; Santschi, 1919a PDF: 345; Emery, 1925d PDF: 52; Prins, 1965b: 77.Status as species: Dalla Torre, 1893 PDF: 176; Emery, 1921g: 102; Wheeler, 1922: 227; Santschi, 1928f PDF: 211; Bolton, 1995b: 298.Senior synonym of Oecophylla brevinodis: Wheeler, 1922: 945.See also: Gotwald, 1973 PDF: 72; Hölldobler & Wilson, 1978 PDF: 19.Plate XX, Figures 1 and 2; Text Figures 58 and 59
Faradje, [[worker]], [[queen]], [[male]]; Malela, [[worker]]; San Antonio, [[worker]] (Lang and Chapin); Katala, [[worker]]; Leopoldville, [[worker]] (J.Bequaert).
The following differences between this species and smaragdina may be noted. In the worker the polymorphism is greater, for not only do the individuals of the same colony show a greater range in size (from 3 to 9 mm.) but the minimae differ more from the mediae and maximae in the shape of the thorax and petiole. The head of the worker longinoda is distinctly more triangular than that of smaragdina , being broader behind, with less convex sides; the eyes are distinctly larger, the mandibles shorter, the clypeus more nearly subcarinate behind, its anterior border sometimes feebly and sinuately emarginate in the middle, the pronotum less convex, the petiole decidedly stouter, more thickened behind, with the stigmata much less prominent when the segment is viewed from above and its ventral surface much more convex anteriorly on the ventral side, when viewed in profile. The sculpture, pilosity, and color are very similar in the two species, but in longinoda the integument is more decidedly opaque, the mandibles are somewhat more coarsely striated, always darker, being concolorous with the posterior portion of the head, at least in the large workers and especially in the dark varieties. The transverse furrow on the second and succeeding gastric segments just behind the anterior border is more pronounced in longinoda .
The female of this species measures 12 to 14 mm. (wings 16 mm.) and is, therefore, distinctly smaller than the corresponding sex of smaragdina , which measures 15 to 17 mm. (wings 18 to 19 mm.). The body of the African species is much more opaque throughout, the wing-veins more heavily bordered with dark brown, and the transverse bands at the bases of the second and following gastric segments are broader, darker, and more sharply marked off from the remainder of the segments. The green portions of the typical longinoda female are slightly more olivaceous and less pea-green, and the basal bands of the gaster are more exposed and brownish; the appendages are more brownish.
The male longinoda is scarcely smaller than that of smaragdina , and measures 6 to 6.5 mm., but the head, thorax, and petiole are darker and more blackish; the head is decidedly broader, especially behind, the mandibles, petiole, antennal scapes, and wings are decidedly shorter and the integument is less shining.
Fig. 58. Oecophylla longinoda (Latreille) , a, body of worker major in profile; b, head of same: c, body of worker minima in profile; d, head of same.
The workers of the various subspecies and varieties of the two species may be separated by means of the following key.
1. Petiole very slender, its stigmata seen from above very prominent, its ventral surface nearly straight or very feebly convex in profile ( smaragdina )....2.
Petiole stouter and higher, its stigmata seen from above not prominent, its ventral surface strongly convex in profile ( longinoda )..................7.
2. Body ferruginous or testaceous.........................................3.
Gaster and sometimes the head pea-green, head more rounded and less truncated behind; size smaller, petiole somewhat shorter (Queensland, New Guinea, Islands Aru and Key).................subspecies virescens (Fabricius) .
3. Integument opaque or subopaque.......................................4.
Integument more or less distinctly shining..............................5.
4. Color ferruginous (India, Ceylon, Cochin China, Indonesia). smaragdina (typical).
Smaller and more testaceous, mesonotum and petiole a little narrower (Java). variety gracilior Forel.
5. Large forms, integument slightly shining (Papua, Philippines, Melanesia). subspecies subnitida Emery. Smaller forms, integument more shining................................6.
6. Body very shining and slender, color testaceous, head rather elongate (Island of Batjan)..................................... variety gracillima Emery.
Less shining and less slender, head shorter (Celebes). variety selebensis Emery.
7. Ferruginous or testaceous throughout...................................8.
Brown or black........................................................9.
8. Color ferruginous (West Africa)........................ longinoda (typical).
Color paler, more testaceous, petiole shorter, head slightly broader, apical tooth
of mandibles shorter (Zanzibar)............... variety textor (Santschi). 9. At least the thorax and mandibles black................................10.
Body rather uniformly brown (Belgian Congo). variety annectens , new variety .
10. Head dull red, gaster often brownish (Belgian Congo).. variety rubriceps (Forel).
Head and gaster black or dark brown (Belgian Congo, Nigeria, Liberia, Cameroon, Spanish Guinea)................... variety fusca (Emery).
Oe. fusca was originally described by Emery as an independent species, but Forel reduced it to subspecific rank on finding the variety rubriceps , which shows some color variation in the direction of the typical longinoda . The discovery of another variety, annectens described below, connecting rubriceps and longinoda is additional evidence that fusca cannot be maintained as a species. In my opinion it is merely an extreme melanic variety, for I am unable to detect in it any morphological characters of even subspecific value. All of the varieties of longinoda are equally polymorphic in the worker caste and the smallest individuals all agree with the description of Andre's brevinodis , except in color.
The ethological observations of Chun1 and Father Kohl2 refer to this species.
Mr. Lang's photographs reproduced on Pl. XX, figs. 1 and 2, show two of the nests of the typical longinoda from Malela, consisting of the leaflets of a bush skillfully folded and united with the white silk spun by the young larvae. He found that the nests of longinoda and its varieties are most often constructed on bushes and are sometimes only a few feet from the ground. Text Fig. 59 shows a nest of this ant placed in a coffee tree at Avakubi. The habits seem to be the same in all essential particulars as those of smaragdina .
[[ worker ]]. - D'un roux ferrugineux legerement plus fonce que le type; le gastre un peu plus brunatre. Differe surtout du type par ses mandibules d'un jaune roussatre beaucoup plus clair que la tete et comme les appendices y compris le scape qui est concolore.
[[ queen ]]. - - Taille de la [[ queen ]] type dont elle differe par la couleur d'un vert plus tendre, comme chez smaragdina , tandis que chez longinoda le vert est plus sombre, surtout sur le gastre. Chez claridens le bord des segments n'est pas obscurci mais plutot un peu roussatre. Le milieu de l'epistome, l'aire centrale et les angles posterieurs de la tete, trois bandes bordant les sillons du mesonotum, sutures thoraciques pedicule du petiole et appendices d'un jaune roussatre plus clair que chez le type. Aile longue de 15 mm.
Cote d'Ivoire: Grand Bassam (Lohier leg.).
Plate XX, Figures 1 and 2; Text Figures 58 and 59
Faradje, [[worker]], [[queen]], [[male]]; Malela, [[worker]]; San Antonio, [[worker]] (Lang and Chapin); Katala, [[worker]]; Leopoldville, [[worker]] (J.Bequaert).
The following differences between this species and smaragdina may be noted. In the worker the polymorphism is greater, for not only do the individuals of the same colony show a greater range in size (from 3 to 9 mm.) but the minimae differ more from the mediae and maximae in the shape of the thorax and petiole. The head of the worker longinoda is distinctly more triangular than that of smaragdina , being broader behind, with less convex sides; the eyes are distinctly larger, the mandibles shorter, the clypeus more nearly subcarinate behind, its anterior border sometimes feebly and sinuately emarginate in the middle, the pronotum less convex, the petiole decidedly stouter, more thickened behind, with the stigmata much less prominent when the segment is viewed from above and its ventral surface much more convex anteriorly on the ventral side, when viewed in profile. The sculpture, pilosity, and color are very similar in the two species, but in longinoda the integument is more decidedly opaque, the mandibles are somewhat more coarsely striated, always darker, being concolorous with the posterior portion of the head, at least in the large workers and especially in the dark varieties. The transverse furrow on the second and succeeding gastric segments just behind the anterior border is more pronounced in longinoda .
The female of this species measures 12 to 14 mm. (wings 16 mm.) and is, therefore, distinctly smaller than the corresponding sex of smaragdina , which measures 15 to 17 mm. (wings 18 to 19 mm.). The body of the African species is much more opaque throughout, the wing-veins more the typical form of the species. I am unable to say, therefore, whether Oe. smaragdina , actually occurs on the African continent.
According to Emery, longinoda is the most primitive of the existing forms of Oecophylla , because most closely allied to Oe. sicula , which he described from the Miocene amber of Sicily. In the Baltic amber I have recognized two species of the genus, Oe. brischkei Mayr and brevinodis Wheeler . As the latter name is preoccupied by brevinodis Andre , which was based, as I have shown, on the minima worker of longinoda , I suggest that the fossil species be called crassinoda (new name). In the shape of the petiole both of the Baltic amber forms, being of Lower Oligocene age and therefore older than sicula , are also more like longinoda , and especially its smaller workers, than the Oriental smaragdina .
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Oecophylla longinoda (common name weaver ant) is a species of arboreal ant found in the forested regions of tropical Africa. They are one of only two extant species of the genus Oecophylla, the other being O. smaragdina. They make nests in trees made of leaves stitched together using the silk produced by their larvae.
The worker is a fairly large ant with a length of 6 mm (0.24 in). The antennae have twelve segments, the first segment exceeding in length the second and third combined. The clypeus, at the front of the head, is large and convex and overhangs the outer edge of the mouthparts. The large mandibles have long triangular teeth which cross over one another when the ant is at rest. This ant ranges in colour from orangeish-brown to dark brown; the thorax is clad in fine pubescence while the abdomen is covered with short erect hairs. The tip of the abdomen has glands that produce pheromones. The feet have suction pads which enables these ants to cling to surfaces with a firm grip.[2]
This weaver ant is widely distributed across the rainforests of sub-Saharan Africa. It is found high in the canopy and one colony can dominate the crown of one tree or spread across several trees.[2]
After her nuptial flight, a newly mated queen founds a colony in an out of the way part of the canopy. At first she guards the eggs and cares for the growing larvae herself, feeding them out of her bodily reserves, and not going out to forage. She may lose 60% of her body weight during this period. When fully grown the larvae pupate, finally emerging as adult workers about thirty days after the eggs were laid. The workers now take over the building of nests and the care of the young, and the queen devotes herself to the laying of eggs, producing some hundred a day.[2]
A weaver ant colony consists of a large number of nests between which ants move at will. The nests are made by binding leaves together using silk produced by the final stage larvae. The queen inhabits one of these nests while the others are used by the worker ants to live in and care for the brood. The ants occupy a three dimensional territory in the treetops, driving off other ants of their own or other species aggressively, and usually creating a "no-ants-land" where the territory abuts on that of another colony. They are voracious predators, foraging on the ground as well as in the trees for insects and other arthropods, and co-operating with each other to tackle large prey.[3] They also feed on the honeydew produced by scale insects, and the ants maintain herds of scale insect for this purpose.[2]
O. longinoda is a natural enemy of the coconut bug (Pseudotheraptus wayi), a pest that has caused up to 67% of the coconut crop in Tanzania to be lost. The weaver ant competes with other species of ant living among the coconut palms, and is sometimes displaced by the ground-based Pheidole megacephala. However, the weaver ant is considerably more effective as a biological pest control agent, and baits are used to selectively control P. megacephala, allowing the weaver ants to flourish and control the coconut bugs.[4][5]
Nest in Ghana Oecophylla longinoda (common name weaver ant) is a species of arboreal ant found in the forested regions of tropical Africa. They are one of only two extant species of the genus Oecophylla, the other being O. smaragdina. They make nests in trees made of leaves stitched together using the silk produced by their larvae.
