Trail Substance Research Articles

Context is everything: mapping Cyphomyrmex-derived compounds to the fungus-growing ant phylogeny

Ants communicate using a suite of chemicals with a level of sophistication that is inextricably linked to their ecological dominance. The fungus-growing ants have been the focus of chemical ecology studies for decades, especially the leaf-cutting ants. Some create long, conspicuous foraging trails to harvest fresh vegetation used to sustain large farming systems that feed millions of workers. However, of the ca. 250 fungus-growing ant species, most feed detritus rather than fresh material to their gardens, and colony sizes are tens to hundreds of workers. Colonies within the attine genus Cyphomyrmex use distinct methods of agriculture (i.e., yeast and lower fungus agriculture). We compared compounds found in five species from the yeast-growing Cyphomyrmex rimosus group (C. rimosus and C. salvini) and the lower agriculture Cyphomyrmex wheeleri group (C. costatus, C. longiscapus, C. muelleri). Compounds identified were compared with those reported in the literature and mapped onto the attine-ant phylogeny, and glands of origin suggested. There were 10 compounds across five species and two are known alarm compounds, 1-octen-3-o1 and 3-octanol. Of the six farnesenes detected, the most notable was the diversity of gaster-derived compounds in C. salvini and the high abundance of (3Z, 6E)-α-7-ethylhomofarnesene and α-6-bishomofarnesene in the three C. wheeleri group species. We also found 2,5-dimethyl-3-isoamylpyrazine in the heads of yeast-growing species, an unexpected result because pyrazines are known trail substances in other attines. Our results expand our understanding of semiochemicals found in fungus-growing ants and provides a starting point to generate hypotheses for more extensive comparative studies.

Factors influencing release of hostmarking pheromone byRhagoletis pomonella flies

The effect of fly or fruit treatments on quality and/or quantity of host-marking pheromone (HMP) trail substance released by apple maggot flies (Rhagoletis pomonella) following oviposition was evaluated. Among flies, considerable variation existed in the amount of HMP substance deposited, but overall, the amount of substance released on successively offered fruit (over a day or a week) did not change appreciably. Fly diet did not influence pheromone activity. Older flies (28 days) or smaller flies released less or less active HMP trail substance than younger flies (14 days) or larger flies. Females deposited a similar amount of trail substance on large (18-19 mm diam.) or HMP-marked fruit as on small (12-13 mm) or unmarked fruit. Starvation reduced the amount of measurable trail substance deposited but resulted in a more active HMP deposition. Discrepancy between trail measurement and behavioral bioassay results for the starvation treatment indicated that trail measurement results may be misleading under conditions that reduce gut contents of the fly.

Individual specific trails in the antLeptothorax affinis (Formicidae: Myrmicinae)

Leptothorax affinis lays chemical trails during nest emigration. Workers which carried colony members during nest movement refused trails of nest mates and searched for their own trails. The origin of the individual specific trail substance could not be localized.

Morphology and ultrastructure of the abdominal glands in Dolichoderine ants (Hymenoptera, Formicidae)

Ants of the subfamily Dolichoderinae possess four major abdominal glands. The lack of a functional sting probably explains the rather moderate development of the sting associated poison and Dufour's glands. The extremely large pygidial gland has become the main source of the dolichoderine defensive secretions, while the Pavan's gland, when present, produces the trail substances. The large tergal gland between tergites 6 and 7, formerly called the anal gland, due to its anatomical position and general morphological characteristics, is homologous to the pygidial gland, which is found inaall other ant subfamilies. Pavan's gland, on the other hand, is apparently a peculiarity to the Dolichoderinae and Aneuretinae. The sac-like appearence of the Pavan's gland only represents the resevoir part, while the real secretory component of the gland is to be located in the thickened epithelium of the seventh abdominal sternite. Ultrastructural examination reveals a well-developed smooth endoplasmic reticulum along with numerous mitochondria as the major cytoplasmic constituents in the pygidial, Dufour's and Pavan's gland. Both characters can be related to the lipophilic secretion of these glands, while the moderately developed granular endoplasmic reticulum of the poison gland secretory cells may point to some protein synthesis. Both the pygidial and poison gland are comprised of individual secretory units with a glandular cell and its own duct cell, while the Dufour's and Pavan's gland correspond to the glandular epithelium type.

Orientation and recruitment behavior in the ponerine ant Pachycondyla tesserinoda (Emery): laying of individual-specific trails during tandem running

Tandem leaders of Pachycondyla tesserinoda mark their way during nest moving. While scouting and foraging for food in an unknown area, chemical orientation is used as well. The origin of the trail substance could not be identified. Secretions of gastral exocrine glands did not induce trail following behavior. Nor do these secretions elicit tandem-following reactions; rather the latter is released by the general body surface odor. The trail substance and the substance used for marking the nest entrance are colony-specific. Moreover, individual tandem leaders recognize and show a preference for their own trails. This extraordinary effect is independent of the age of the trail. P. tesserinoda workers search individually for food and new nest sites. Targets which are important for the colony are directly shown to nestmates by tandem running. Due to this type of foraging and scouting individual-specific trails may be advantageous for this ant.

Tandem Recruitment and Trail Laying in the Ponerine Ant Diacamma rugosum: Signal Analysis1

AbstractDuring nest emigration, Diacamma rugosum scouts recruit female nestmates to the new nest site by tandem running. ♂♂, brood and prey objects are carried.The tandem leaders stimulate their nestmates to follow them by pushing or, more rarely, pulling them with the mandibles.The signals releasing the following behaviour are mainly chemical. Only 15–30% of motivated followers react positively to an odourless paper or wax dummy. The ♀♀ follow cut‐off thoraces, legs and gasters plugged at the end or without hind gut and sting apparatus, just as well as a leading ant. The ants even follow a dummy consisting of body parts if they are not in direct mechanical contact with it. The leading effect of the body surface is not reduced by intensive cleaning with water or by extraction in solvents of different polarity. Only maceration in potash lye eliminates the leading effectiveness of the cuticula. None of the secretions of the tested abdominal glands release following behavior. Only the hind gut fluid possesses leading signal qualities. No distribution of faeces over the bodies of the leading ants can be observed before or during tandem running. The faecal pheromone responsible for this leading effect does not seep into the superficial layer of a leader dummy made from bee wax but it can be washed off with water. These results show that the actual signal releasing tandem following is an unspecific odour substance of the cuticula surface. The presence of the hind gut fluid is not necessary for the tandem following response. It may be an additional signal. During nest emigration the hind gut fluid is scattered patchily in the form of small droplets by the nest finders on their way to the new nest. No increased deposition of faecal droplets could be observed on the way to repeatedly visited rich food sources.The hind gut fluid serves as a long lasting trail substance and has an exclusively orienting effect. The secretions of the other abdominal glands are not trail pheromones. The nest entrance is marked colony‐specifically.

Food recruitment strategies of the ants Myrmica sabuleti and Myrmica ruginodis

The food-gathering systems of Myrmica sabuleti and Myrmica ruginodis are analysed and compared to those, previously described, of M. rubra and M. scabrinodis. Workers of the two species studied in this paper collect pure water or small dead prey without actively recruiting congeners. Collecting ants of M. ruginodis lay down a trail pheromone from their poison gland only when returning to the nest, while foragers of M. sabuleti deposit a trail on their way both to the nest and back to the food but almost only in darkness. Collecting ants of both species are not followed by the few workers which, excited by them in the nest, individually reach the food. In the two species studied, an active recruitment of workers occurs when a large dead prey or a source of sugared water is presented to a colony. After having deposited their trail on their way to the nest, recruiting ants ‘invite’, by tactile signals, congeners to leave the nest. Then the recruiting ants return to the food, laying down their attractive Dufour's gland content along distances varying with the species and the food stimuli considered. Recruiting ants of M. ruginodis generally emit their Dufour's gland secretion along longer distances than M. sabuleti foragers, after which they secrete nothing more, while M. sabuleti workers go on their way to the food laying down their trail substance again. The food-gathering technique of the two species studied includes group recruitment, performed on longer distances in M. ruginodis than in M. sabuleti, followed by mass recruitment. The number of ants finally recruited onto food is generally excessive in M. ruginodis, and in M. sabuleti the site is only just saturated. A comparison of these food-collection techniques with those of different species of Myrmica, together with a chemical and an ethological study of these species' pheromones would provide information for a better understanding of these species' ecology, as well as taxonomic and phylogenetic positions.

Trail substance in larvae of Eriogaster lanestris L.

Trail substance in larvae of Eriogaster lanestris L.

Weaver ants: social establishment and maintenance of territory.

Workers of the African weaver ant Oecophylla longinoda recruit nestmates to previously unoccupied space by means of odor trails laid from the rectal gland, a hitherto unrecognized musculated organ located at the rear of the rectal sac. When enemy ants and other intruders are encountered on the territory, the Oecophylla assemble nestmates into small resting clusters by dispensing an attractant-arrestant pheromone from the sternal gland, a second newly discovered organ located on the last abdominal sternite. Under prolonged stress, additional forces are recruited to the combat area with the aid of the rectal-gland trail substance.

Behavioral Observations on African Army Ants of the Genus Aenictus (Hymenoptera: Formicidae)

Behavioral Observations on African Army Ants of the Genus Aenictus (Hymenoptera: Formicidae)

Measurements of diatom adhesion and their relationship with movement

Adhesive and tractive forces of diatoms have been measured by the bending of a glass fibre. The results show that motility depends on attachment to the substrate. Movement on girdle bands occurs when the raphe acts against lumps of trail substance. Resistance to shear stress in laminar flow through a capillary tube is found to be particularly high in large epipsammic spp., e.g. Amphora ovalis, and is related to strong adhesion. The mechanism of movement is discussed in relation to the physical properties of the raphe and trail.

Purification of the Fire Ant Trail Substance

THE fire ant, Solenopsis saevissima (Fr. Smith), utilizes a trail substance as an aid in effective foraging1. Workers secrete a substance from the Dufour's gland which is deposited from the sting in the form of minute streaks. These mark a trail from a suitable food source to the nest. Workers are strongly attracted to this substance and follow the trail outward to the food source. The newly recruited workers in turn lay trails to the nest, reinforcing the original trail. The appropriate properties for effective trail substances have been discussed by Bossert and Wilson2.

The Anatomical Source of Trail Substances in Formicine Ants

The Anatomical Source of Trail Substances in Formicine Ants

Chemical communication among workers of the fire ant Solenopsis saevissima (Fr. Smith) 1. The Organization of Mass-Foraging

1. 1. Recruitment in mass foraging is organized almost exclusively by the use of the trail substance, which is secreted by Dufpur's gland and released through the extruded sting. The secretion is a powerful attractant, which excites workers and draws them out of the nest in the direction indicated by the trail. No other stimuli are required to induce this behaviour. The initial build-up of workers at food masses is exponential. The build-up decelerates towards a limit as workers become crowded on the food mass because (1) workers unable to reach the mass turn back without laying trails, and (2) the trail deposits of single workers evaporate within a few minutes. As a result, the number of workers at food masses tends to stabilize at a level which is a function of the area of the food mass. But the nature of the communication requires that the feed-back system have a lag of up to several minutes. The lag is measurable in the “overshoot” of numbers of approaching workers and is a function of the distance of the food mass from the nest. 2. 2. Trail-laying, as measured by the extrusion of the sting, is an all-or-none response of individual workers; hence individual trails do not communicate quantity or quality of the food find. Quantity of food is communicated in the mass response by means of the negative feedback control of build-up just described. Quality is communicated by means of an “electorate” mass response, in which individuals choose whether to lay trails after inspecting the food find. The more desirable the food find, the higher the percentage of positive responses, the more the trail substance presented to the colony, and hence the more the newcomer ants that emerge from the nest. 3. 3. The trail substance is highly species-specific. In transposition experiments utilizing the fire ant species Solenopsis saevissima, S. geminata, and S. xyloni, it was found that the geminata secretion is certainly different from that of the other two species. The secretions of saevissima and xyloni are more interchangeable but appear to differ somewhat. The thief-ant S. molesta and members of other myrmicine genera tested also do not share the saevissima trail substances. Curiously, the Dufour's gland secretion of the dolichoderine species Monacis bispinosa causes a full response in saevissima workers, but M. bispinosa uses another substance for its trails. 4. 4. The foraging and homing behaviour of individual workers is partially analysed. An unexpected response, in which workers are attracted and lay trails to unexplored areas near the nest, is described.

Chemical communication among workers of the fire ant Solenopsis saevissima (Fr. Smith) 3. The experimental induction of social responses

1. 1. The following categories of social behaviour among fire ant workers are known to be mediated principally by chemical releasers: recruitment in mass-foraging, recruitment in colony emigration, alarm, grooming, and elementary attraction leading to clustering. Each behaviour pattern can be induced, wholly or in part, by the experimental presentation of chemical substances removed from the bodies of the workers. 2. 2. Colony emigration is organized by odour trails in a manner nearly identical to that employed in mass-foraging. Incipient emigration has been induced with massive doses of extracted trail substance. 3. 3. Alarm behaviour is released principally by a volatile cephalic substance and intensified secondarily by the attractant component of Dufour's gland secretion. 4. 4. Grooming behaviour is characterized as glossal licking of objects unaccompanied by trail-laying. It has been induced artificially with certain fractions of fat-soluble extracts made from whole worker bodies. 5. 5. Workers separated from the nest can be induced to orient toward the air removed from around other groups of workers. Indirect evidence has been obtained that one or more simple gaseous excretory products are adequate to produce the response. Carbon dioxide has been used to produce it artificially.