Poison Gland Research Articles

Isolation of the trail pheromone of the ant Myrmica rubra

The trail pheromone of Myrmica rubra is a volatile substance, or substances of low polarity and moderately low molecular weight, in the poison gland contents. The pheromone can be separated and concentrated by the use of thin layer chromatography. The non-polar contents of the poison gland associated with the pheromone vary with caste, age of workers, and species.

Recruitment behavior, orientation, and the organization of foraging in the carpenter ant Camponotus pennsylvanicus degeer (Hymenoptera: Formicidae)

1. The recruitment process of Camponotus pennsylvanicus initiates and regulates foraging activities. Scout ants recruit nestmates to new food sources with alerting motor displays. Workers subsequently leave the nest and follow a recruitment trail that appears to be composed of hindgut material and poison gland secretion (formic acid) to the food. Hindgut material functions as a long-lasting olfactory orientation cue between the food source and the nest, whereas poison gland secretion makes the recruitment trail highly attractive to stimulated ants. Hindgut trails may also have a recruitment effect. 2. Although hindgut material is an important orientation cue during foraging, because ants make repeated foraging runs they may also make use of visual cues. 3. Mass foraging is organized by the behavioral activities of recruiting ants. Starvation intensifies the recruitment displays of scouts, which releases a strong recruitment response in the colony. The behavior of individual recruiters during the organization of foraging facilitates at first a quick mobilization of nestmates to the food; subsequently recruiter behavior changes. These changes the facilitate food transport to the colony. The amount of food brought into the colony along with the decrease in recruitment behaviors may account for the waning and eventual termination of foraging activity. Only ants of a particular age bracket respond to recruitment signals and participate in foraging, and of this group only a small proportion of workers are consistently active in foraging. 4. When compared to other formicine species, the recruitment behavior of Camponotus pennsylvanicus appears to illustrate some features of chemical mass communication while still retaining characteristics of the group recruitment technique.

The behavioral ecology of mating in harvester ants (Hymenoptera: Formicidae: Pogonomyrmex)

1. The four sympatric species of Pogonomyrmex (P. barbatus, P. desertorum, P. maricopa and P. rugosus) frequently conduct their nuptial flights on the same days; however the daily timing rhythms of their mating swarms differ strongly. 2. Mating takes place on species-specific, perennial mating sites. In our study area the mating sites of P. barbatus and P. rugosus were located on the ground, those of P. desertorum and P. maricopa on bushes and trees. 3. Males mark these mating sites with the secretions of their mandibular glands. Apparently additional males as well as females are attracted by these secretions. 4. During mating activities a strong male competition exists. In P. barbatus and P. rugosus an average of 4–5 males, in P. desertorum and P. maricopa an average of 2–3 males simultaneously, compete, for access to one female. 5. Multiple matings have been observed in all four Popogonomyrmex species. 6. Sexual behavior is regulated by a stimulation pheromone produced in the female's poison glands and apparently also by a species-specific surface pheromone which the males perceive only when they approach closely enough to make direct antennal contact. 7. The combination of distinct daily activity rhythms, partial mating site isolation together with the ability of males to discriminate conspecific females from females of the other species isolates the sympatric Pogonomyrmex species from each other. 8. The mating aggregations of Pogonomyrmex are compared with the lek behavior of vertebrates.

Recruitment behavior, home range orientation and territoriality in harvester ants, Pogonomyrmex

1. Scouts of the harvester ant Pogonomyrmex barbatus, P. maricopa and P. rugosus which discovered a new rich foraging area recruit nestmates by laying a trail with poison gland contents from the feeding site to the nest. Laboratory experiments have shown that Pogonomyrmex workers are stimulated to follow the trail by the trail pheromone alone. 2. The biological significance of the recruitment behavior was analyzed in the mesquite-acacia desert in Arizona-New Mexico, where the three species occur sympatrically. P. maricopa recruits less efficiently to food sources than does P. barbatus and P. rugosus. Generally the recruitment activity depends on a number of parameters of the food source, such as distance to the nest, density of the seed fall and size of the grains. 3. The recruitment activity is also affected by the presence, absence or distance of hostile neighboring colonies. 4. The use of chemically and visually marked trunk trails which originate from recruitment trails, guarantees and efficient partitioning of foraging grounds. It could be demonstrated that trunk trails, used by P. barbatus and P. rugosus during foraging and homing, have the effect of avoiding aggressive confrontations between neighboring colonies of the same species. They channel the mass of foragers of hostile neighboring nests into diverging directions, before each ant pursues its individual foraging exploration. This channeling subtly partitions the foraging grounds and allows a much denser nest spacing pattern than a foraging strategy without trunk trails, such as that employed by P. maricopa. 5. The behavioral mechanisms which maintain overdispersion both within and between species of Pogonomyrmex were investigated. Aggressive confrontations at the colony level and aggressive expulsion of foundress queens from the nest territories of mature colonies play thereby a major role. Observational as well as experimental data led to the conclusion that the farther away from its nest the intruder is, the less vigorous are the aggressive confrontations with the defenders. Only when neighboring colonies are located too close together will increased aggressive interactions eventually lead to the emigration of the weaker colony. 6. P. barbatus and P. rugosus have a wide niche overlap, whereas P. maricopa seems to be more specialized in regard to food. This is consistent with the findings that interspecific territoriality between P. barbatus and P. rugosus is considerably more developed than between these species on the one side and P. maricopa on the other. 7. Although foundress queens, which venture into a territory of a conspecific mature colony are fiercely attacked, most of them are not injured, but rather dragged or carried to the territorial border and then released. 8. Nevertheless foraging areas, even of conspecific colonies, frequently overlap, but aggressive interactions there are usually less intense than at the core areas (trunk trails plus nest yards), which normally do not overlap and are vigorously defended.

The organization of colony defense in the ant Pheidole dentata mayr (Hymenoptera: Formicidae)

1. Colonies of Pheidole dentata employ a complex strategy of colony defense against invading fire ants. Their responses can be conveniently divided into the following three phases: (1) at low stimulation, the minor workers recruit nestmates over considerable distances, after which the recruited major workers (“soldiers”) take over the main role of destroying the intruders; (2) when the fire ants invade in larger numbers, fewer trails are laid, and the Pheidole fight closer to the nest along a shorter perimeter; (3) when the invasion becomes still more intense, the Pheidole abscond with their brood and scatter outward in all directions (Figs. 1, 4). 2. Recruitment is achieved by a trail pheromone emitted from the poison gland of the sting. Majors can distinguish trail-laying minors that have just contacted fire ants, apparently by transfer of the body odor, and they respond by following the trails with more looping, aggressive runs than is the case in recruitment to sugar water. Majors are superior in fighting to the minors and remain on the battleground longer. 3. The first phase of defense, involving alarm-recruitment, is evoked most strongly by fire ants and other members of the genus Solenopsis; the presence of a single fire ant worker is often sufficient to produce a massive, prolonged response (Figs. 2, 5, 6). In tests with Solenopsis geminata, it was found that the Pheidole react both to the odor of the body surface and to the venom, provided either of these chemical cues are combined with movement. Fire ants, especially S. geminata, are among the major natural enemies of the Pheidole, and it is of advantage for the Pheidole colonies to strike hard and decisively when the first fire ant scouts are detected. Other ants of a wide array of species tested were mostly neutral or required a large number of workers to induce the response. The alarm-recruitment response is not used when foragers are disturbed by human hands or inanimate objects. When such intrusion results in a direct mechanical disturbance of the nest, simulating the attack of a vertebrate, both minor and major workers swarm out and attack without intervening recruitment.

Communication and orientation during foraging and emigration in the antFormica fusca

1. Scout ants ofFormica fusca lay a hindgut trail from the newly discovered food source to the nest; however, the hindgut material does not have a recruitment effect on nestmates. 2. Inside the nest the recruiting ant performs a waggle motor display and food offerings when facing nestmates head-on. Nestmates are alerted by this behavior and subsequently follow the trail to the food source. 3. Experiments have shown that neither Dufour's gland secretions nor poison gland substance can release trail following behavior. Only ants stimulated by the recruitment performance of the scout ant would follow the hindgut trail. Orientation experiments demonstrated that the hindgut trail serves as an important orientation cue during foraging activities. 4. Also during nest emigrations recruiting ants lay chemical trails with hindgut contents, and again it could be demonstrated that the trails function only as orientation cues. Also in this case the alerting signal consists of a specific motor display. During nest emigrations most of the recruits, however, are carried to the target area by only a relatively small number of so-called “transporting specialists.” 5. The recruitment technique employed byFormica fusca, in regard to its organizational level, can be placed between “group recruitment” on the one side and “chemical mass communication” on the other. 6. Although the comparative analysis of the organizational levels of recruitment techniques employed by different formicine species does not necessarily provide direct evidence of the evolutionary pathways of recruitment behavior, it at least allows us to develop a model of the evolutionary steps leading to the highly sophisticated stage of mass communication.

Tandem calling: a new kind of signal in ant communication.

Leptothorax acervorum, L. muscorum, and L. nylanderi recruit nest mates to a new food source by tandem running, with only one nest mate being recruited at a time. This technique is initiated by a special "tandem calling" behavior; the recruiter slants its gaster upward and discharges poison gland secretions from the extruded sting. Nest mates are attracted, and as soon as one of them touches the calling ant, tandem running starts. Further details of the full recruitment sequence are provided. Evidence is presented to suggest that tandem running is the evolutionary precursor of odor-trail communication and sex attraction within certain phylogenetic lines of myrmicine ants.

Histology and Ultrastructure of the Recently Found Buccal Toxic Gland in the Fish Meiacanthus nigrolineatus (Blenniidae)

The buccal gland of Meiacanthus nigrolineatus is situated on the dentary bone, enveloping the base of specialized canine fangs. This gland is 1.2 to 1.5 mm long, and is divided into several lobes by sheets of connective tissue. Each lobe produces secreting cells that ripen, and by holocrinic secretion empty their products in the intercellular spaces. The gland is ductless and the secretion is pressed into the wound along grooves in the fang. Fish-genera related to Meiacanthus (Petroscirtes, Dasson) do not have poison glands in the mouth cavity.

Monoterpene Hydrocarbons in the Poison Gland Secretion of the Ant Myrmicaria natalensis (Hymenoptera: Formicidae)

The occurrence of the monoterpene hydrocarbons, d-limonene and Z-limonene, in the poison gland secretion of Myrmicaria natalensis F. Smith (Grunanger et al. 1960) has made this ant unique among the Formicidae. No other ant species so far investigated has been reported to contain any monoterpene hydrocarbons in an exocrine secretion. In a brief study to determine whether M. natalensis collected in Natal, South Africa, also contained limonene, we found that the poison gland secretion of this species contained a number of additional terpenoid constituents. This report concerns the identification of these other components as additional monoterpene hydrocarbons.

Chemical strategy during foraging in Solenopsis fugax Latr. and Monomorium pharaonis L.

1. Solenopsis fugax, a subterranean ant, lays odorous trails in the tunnels leading to the brood chambers of neighbouring ant species. The recruitment trail pheromone originates from the Dufour's gland. 2. In addition, when preying on the foreign brood, Solenopsis fugax discharges a highly effective and long lasting repellent substance from the poison gland. This prevents the brood keeping ants from defending their own larvae against the predators. 3. A very similar chemical foraging strategy is used by Monomorium pharaonis. A repellent substance enabling Monomorium to compete successfully with other ant species for food sources is discharged. The recruitment pheromone originates from the Dufour's gland; a repellent substance enabling Monomorium to compete successfully with other ant species is discharged from the poison gland.

Effect of parasitism by Cardiochiles nigriceps on food consumption and utilization by Heliothis virescens

Parasitism of Heliothis virescens larvae by the endoparasitoid Cardiochiles nigriceps resulted in a reduction in the amount of food consumed by parasitized larvae. This effect was attributed in part to inoculation of material from the accessory reproductive glands of the female at the time of oviposition. Injection of solutions of either the calyx fluid or the poison gland (0·04 gl/larva) into non-parasitized larvae resulted in a reduction in the amount of food consumed by these larvae. A 1 : 1 mixture of these glands (total of 0·04 gl/larva) appeared to be more active than either of the two glands alone. Both of these glands were essential for total activity since larvae parasitized by females lacking the poison gland (poi gl − female) continued to eat and consumed more food than did those parasitized by a normal female. Parasitism resulted in a slower rate of crop-emptying. This effect was, however, shown to be a result of the quantity of food consumed. Inhibition of gut movement was therefore not considered the cause for the reduction in the amount of food consumed by parasitized larvae. The effect of parasitism on the ability of H. virescens larvae to utilize ingested food was partially reduced by parasitism. Larvae parasitized by a normal female were less efficient than non-parasitized larvae in digesting food. Those larvae parasitized by a poi gl − female did not convert as much of their food to body substance as did non-parasitized larvae. Injection of solutions of accessory glands into non-parasitized larvae did not cause these effects.

Phéromones agrégeant les ouvrières de Myrmica rubra

The workers of Myrmica rubra aggregate around a source of one of their secretions, which can be called ‘alarm pheromone’, and also around workers of Lasius flavus. The mechanism of these aggregations differ. Both L. flavus workers and a solution in liquid paraffin of 3-octanol, one of the mandibular gland compounds, act as an arrestant for the workers of M. rubra. Both Dufour's gland secretion and a source of 3-octanone, the major compound of the mandibular gland secretion, are true attractants. The poison gland secretion, a mixture of 3-octanone and 3-octanol in liquid paraffin and a solution in liquid paraffin of 3-nonanone, a minor mandibular gland compound, all induce klinokinesis. The secretion of the mandibular glands and the secretion of the venom apparatus both cause positive klinokinesis and taxis. These locomotory reactions increase the probability that an object, marked by nest mates with these secretions, will be detected by several workers. When presented alone, 3-octanone is the only attractive compound in the mandibular gland secretion. However, a mixture of 3-octanone and 3-octanol (15 per cent of 3-octanol in the vapour phase) is detected more easily by the ants. The diffusion coefficients of the two compounds are different, and a mixture of these substances creates not only a quantitative but also a qualitative odour gradient. This may explain the synergy of the mixture.

Estrogen and brood pouch formation in the marsupial frog, Gastrotheca riobambae.

AbstractImmature female Gastrotheca riobambae were treated with either 1 μg or 10 μg estradiol daily for 24 days. Both estrogen dosages elicited formation of the brood pouch, a dorsal integumentary structure which contains eggs or larvae during the breeding season. A decrease or loss of epidermal keratin, dermal chromatophore units and dermal poison glands occurred during both normal and estrogen‐induced pouch formation. Also, pouch skin exhibited dermal hypervascularity and connective tissue hyperplasia. The epidermis lining the pouch lumen possessed crypts. The importance of these changes is discussed in relation to pouch function.

Synergistic bio-effects of oil and irradiation in an aquatic organism, Taricha granulosa.

One group of newts was irradiated but not exposed to oil; a second group was exposed to oil but not irradiated; a third group was exposed to oil and radiation; and the control group received neither oil or radiation. X radiation was administered in doses of 1,000; 2,500; 5,000; or 10,000 rads. The behavior, physical appearances, and mortality of the newts were observed. Histological examinations were made of tissues following death of the ainmals. Graphs are presented to show survival time of newts. The cause of death of irradiated newts was anemia and lesions of the skin and other tissues. High concentrations of oil without irradiation resulted in dilatation of poison glands and skin denudation, and radiosensitivity was increased by exposure to oil. (HLW)

The rôle of the calyx and poison gland of Cardiochiles nigriceps in the host-parasitoid relationship

Parasitism of Heliothis virescens by Cardiochiles nigriceps reduced the growth of the host. Both the poison gland and the calyx of the female parasitoid were important in reducing the growth of the parasitized host. Injections of poison gland contents (0·04 gl/larva) or calyx fluid (0·04 gl/larva) into H. virescens larvae did not affect their growth. However, a mixture of the two glands (1:1) at this low dosage significantly reduced the weight gained by Heliothis larvae. Heliothis larvae parasitized by parasitoids from which the poison gland was removed (poi gl − females) grew significantly larger than those larvae parasitized by either a normal female or by a female from which the alkaline gland was removed (alk gl − female). The injection of poison gland material (0·04 gl/larva) into larvae which were parasitized by poi gl − females reduced the weight of these larvae to within the limits of larvae parasitized by normal females. The development of larval parasitoids which hatched from eggs of poi gl − females is abnormal. The time of larval development for the parasitoids from poi gl − females is significantly longer than that for the parasitoids from normal females or from alk gl − females. In addition 34 per cent of parasitoids from poi gl − females did not successfully complete development whereas only 10 per cent of the parasitoids from normal and alk gl − females failed to complete development. Injection of poison gland contents into a host parasitized by poi gl − females allowed normal larval development of the parasitoid. These results suggest that the poison gland material and the calyx fluid act synergistically to regulate the growth of parasitized H. virescens larvae. It is speculated that the reason for abnormal development of the larval parasitoids from poi gl − females is because of the lack of control of the host development in the absence of the poison gland material.

Digestive and reproductive systems of Eriborus molestae Uchida (Hymenoptera : Ichneumonidae)

The digestive tract and internal reproductive systems of adult Eriborus molestae Uchida are described. The foregut consists of a short pharynx, a long narrow oesophagus extending into the abdomen beyond the petiole, an expandable, thin-walled crop, and proventriculus. The midgut is simple and surrounded by circular muscles. The hindgut has 3 divisions: ileum, colon, and a rectum with 2 regions. The 24–32 malpighian tubules lie free in the abdominal cavity. The female reproductive system consists of a pair of ovaries, lateral oviducts, a common oviduct, spermatheca, vagina, and 2 accessory glands. There are 14 polytrophic ovarioles per ovary. The distal end of the lateral oviduct is enlarged into an elongate calyx for the storage of 30 or more sausage-shaped ova. Dufour's gland and a poison gland consisting of a poison sac and free filaments are present. The male reproductive system is simple and typical of parasitic Hymenoptera, consisting of a pair of fused testes, vasa deferentia, seminal vesicles, a common ejaculatory duct, and 1 accessory gland.

Phéromones stimulant et inhibant l'agressivité chez Myrmica rubra

The aggressiveness of Myrmica rubra workers is stimulated by their poison gland secretion. On the other hand, the major compound of the mandibular gland, 3-octanone, markedly suppresses their aggressiveness. The inhibitory activity of 3-octanone is still effective when dissolved in liquid paraffin at a concentration of 10 −9 vol./vol. At a concentration 100 times greater in liquid paraffin, 3-nonanone may also suppress the aggressiveness of the ants. This substance however represents only a trace of the mandibular secretion. Neither 6-methyl-3-octanone, nor 3-octanol, possesses an inhibitory effect on the aggressiveness of the ants even when present in liquid paraffin at a concentration 10 4 times greater than the lowest effective dilution of 3-octanone. The relative proportions of 3-octanol and 3-octanone vary greatly in the mandibular gland secretion of the workers from the same nest or from different nests of the same species. The proportions of 3-octanol in the mixture of octanol+octanone present in the vapour released by one crushed worker head range from 4·6 to 38·0 per cent. The histogram of these proportions is unimodal, with the mode situated near 15 per cent of 3-octanol. A mixture of 3-octanol and 3-octanone in liquid paraffin, releasing a vapour containing 15 per cent of 3-octanol, has no more activity than a solution containing only 3-octanone. There is no reason to believe so far that a mixture of 3-octanol and 3-octanone of precise composition has any particular meaning for the ants. We suggest that the ants when attacked emit the inhibitory and stimulative pheromones in such a way that the aggressiveness of the alarmed workers is directed toward the enemy without their being themselves the victims of this aggressiveness.

Cytochemical studies on the poison gland of honey-bee sting.

Cytochemical studies on the poison gland of honey-bee sting.

THE BIOLOGY OF THE SOCIAL WASPS (HYMENOPTERA, VESPIDAE)

THE BIOLOGY OF THE SOCIAL WASPS (HYMENOPTERA, VESPIDAE)

Sex pheromone in the ant Xenomyrmex floridanus

During nuptial flights males of the ant Xenomyrmex floridanus are chemically attracted to females. The female sex pheromone is produced in the poison gland and in addition to being an attractant releases copulatory behaviour in males. This is the first proof of an occurrence and source of a female sex pheromone in an ant.