Mating Flight Research Articles

Mating flight duration ofApis melliferaqueens: As short as possible, as long as necessary

Polyandry in queen honey bees (Apis mellifera) prolongs the duration of nuptial flights which increases costs and risks. Under conditions of limited drone numbers the hypothesis was tested whether or not there is a threshold for successful mating during mating flight. In 29 queens we found a significant negative correlation between mating flight duration and number of spermatozoa in the spermatheca (Pearson r = −0.38, P = 0.04). This negative correlation supports the idea that queens continuously get information on her mating success during flight and return to the colony as soon as they have met a sufficient number of drones. In case of normal availability of drones queens fly from 10 to 30 minutes, so we compared 2 groups of queens (flight duration less than 30 versus more than 30 minutes). Sperm numbers differed significantly between the two groups (3.0 ± 0.77 and 1.1 ± 1.04 million, Wilcoxon, P < 0.001). These results further indicate that queens monitor mating success during flight.

The role of storage proteins in colony-founding in termites

Hexameric storage proteins are widespread in insects and provide a source of amino acids when demand is high and intake is limited, such as during metamorphosis. We investigated the occurrence of storage protein levels in alates and in colony founding pairs in a dry-wood nesting species and two soil-nesting species of termites. Females and males contained similar quantities of storage protein at the time of the mating flight. Alates of soil-nesting species contained much higher levels of storage protein than the wood nesting species. After eggs hatched, protein stores plummeted in both sexes of both ecological types. Greater storage by alates of soil-nesting species is correlated with lack of access food during founding and the larger number of workers produced in their first broods.

A honey bee odorant receptor for the queen substance 9-oxo-2-decenoic acid

By using a functional genomics approach, we have identified a honey bee [Apis mellifera (Am)] odorant receptor (Or) for the queen substance 9-oxo-2-decenoic acid (9-ODA). Honey bees live in large eusocial colonies in which a single queen is responsible for reproduction, several thousand sterile female worker bees complete a myriad of tasks to maintain the colony, and several hundred male drones exist only to mate. The "queen substance" [also termed the queen retinue pheromone (QRP)] is an eight-component pheromone that maintains the queen's dominance in the colony. The main component, 9-ODA, acts as a releaser pheromone by attracting workers to the queen and as a primer pheromone by physiologically inhibiting worker ovary development; it also acts as a sex pheromone, attracting drones during mating flights. However, the extent to which social and sexual chemical messages are shared remains unresolved. By using a custom chemosensory-specific microarray and qPCR, we identified four candidate sex pheromone Ors (AmOr10, -11, -18, and -170) from the honey bee genome based on their biased expression in drone antennae. We assayed the pheromone responsiveness of these receptors by using Xenopus oocytes and electrophysiology. AmOr11 responded specifically to 9-ODA (EC50=280+/-31 nM) and not to any of the other seven QRP components, other social pheromones, or floral odors. We did not observe any responses of the other three Ors to any of the eight QRP pheromone components, suggesting 9-ODA is the only QRP component that also acts as a long-distance sex pheromone.

NEW PARISH RECORDS OF COPTOTERMES FORMOSANUS (ISOPTERA: RHINOTERMITIDAE) IN LOUISIANA

The Formosan subterranean termite (FST), Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), is 1 of 9 termite species currently present in Louisiana (Messenger 2002). The FST is a destructive, introduced pest species indigenous to Southeast China. Its transport from the Pacific theater following WWII resulted in the establishment of this economically important pest in multiple port cities, including New Orleans and Lake Charles, LA (Spink 1967). Since its original introduction, the distribution of the FST has increased both within the state of Louisiana and throughout the southern United States (Messenger et al. 2002; Woodson et al. 2001). Populations of FST have been reported to be established in Texas, Mississippi, Florida, Alabama, Georgia, North Carolina, South Carolina, California, and Tennessee (Su & Tamashiro 1987; Sponsler et al. 1988; Scheffrahn et al. 2001; Woodson et al. 2001; Messenger 2003). Although some increase in range is expected via seasonal nuptial flights (Messenger & Mullins 2005), human transport of infested materials has been implicated as the primary cause of its rapid increase in distribution (La Fage 1987; Scheffrahn et al. 2001; Messenger et al. 2002; Jenkins et al. 2002). In areas where it is established the FST is capable of supplanting native subterranean termites as the primary structural pest species (La Fage 1987). Formosan subterranean termites also routinely attack standing live trees and can cause extensive damage resulting in the weakening of the tree potentially to the point of failure (Osbrink et al. 1999). Because this insect poses an economic threat to wooden structures and live trees, it is imperative to document its increasing distribution throughout Louisiana and other southeastern states.

Determining colony densities in wild honeybee populations (Apis mellifera) with linked microsatellite DNA markers

Estimating the population size of social bee colonies in the wild is often difficult because nests are highly cryptic. Because of the honeybee (Apis mellifera) mating behaviour, which is characterized by multiple mating of queens at drone congregation areas (DCA), it is possible to use genotypes of drones caught at these areas to infer the number of colonies in a given region. However, DCAs are difficult to locate and we assess the effectiveness of an alternative sampling technique to determine colony density based on inferring male genotypes from queen offspring. We compare these methods in the same population of wild honeybees, Apis mellifera scutellata. A set of linked microsatellite loci is used to decrease the frequency of recombination among marker loci and therefore increase the precision of the estimates. Estimates of population size obtained through sampling of queen offspring is significantly larger than that obtained by sampling drones at DCAs. This difference may be due to the more extensive flying range of queens compared with drones on mating flights. We estimate that the population size sampled through queen offspring is about double that sampled through drones.

Reproductive phenologies in a diverse temperate ant fauna

Abstract 1. Ant nuptial flights are central to understanding ant life history and ecology but have been little studied. This study examined the timing of nuptial flights, the synchronicity of nuptial flights (as a potential index of mating strategy), and variation in nuptial flights with elevation and among years in a diverse temperate ant fauna.2. Flights occurred throughout the year, but were concentrated in the beginning of summer and in early fall (autumn). Relative to the entire flight season, closely related species tended to be more likely than expected by chance to fly at similar times, perhaps because of phylogenetic constraints on life history evolution.3. Flights were relatively synchronous within species for nearly all species considered, but synchronicity did not appear to be a robust estimate of overall mating strategy.4. Overall patterns in nuptial flights among species and the timing of flights for individual species varied with elevation, but did not vary greatly among years.5. Although this study is one of the most comprehensive on the reproductive flight phenologies of ants, much remains to be learned about the causes and consequences of such spatial and temporal variation in flight phenology.

Behavioral and Electroantennogram Responses of Phorid fly Pseudacteon tricuspis (Diptera: Phoridae) to Red Imported Fire Ant Solenopsis invicta Odor and Trail Pheromone

The phorid fly, Pseudacteon tricuspis is an introduced parasitoid of the red imported fire ant, Solenopsis invicta in the United States. Previous studies show that phorid flies are attracted to host ant workers at disturbed colonies, to colonies exhibiting aggressive interspecific interactions, and to fire ant mating flights. In a series of behavioral and electroantennogram (EAG) experiments, we confirm the possible use of fire ant odor as cues for host location by P. tricuspis. We tested the response of P. tricuspis of different sex and mating status to several host-related odor stimuli including live fire ant workers, extracts of worker whole body, head, thorax, and abdomen, and (E,E)-α-farnesene, a trail pheromone component of Solenopsis fire ants. Results from Y-tube olfactometer bioassays demonstrated the attraction of mated female P. tricuspis to live S. invicta workers. In addition, extracts of S. invicta worker whole body and thorax elicited strong olfactometer response in female flies (mated and unmated) and mated males, but not in unmated males. Pseudacteon tricuspis did not show significant attraction to extracts of S. invicta worker head and abdomen, or to (E,E)-α-farnesene, irrespective of sex and mating status. In EAG experiments, female and male P. tricuspis showed significant EAG response to extracts of worker whole body, head, and abdomen, and to a less extent, thorax extract, but not to (E,E)-α-farnesene. Females showed slightly greater EAG response than males, but EAG response was not affected by mating status. These results suggest that fire ant thorax is likely the source of kairomones used as host location cues by P. tricuspis, and support the hypothesis that fire ant worker trail pheromones are not likely used by P. tricuspis for host location.

Energy use and allocation in the Florida harvester ant, Pogonomyrmex badius: are stored seeds a buffer?

Limitation of a necessary resource can affect an organism’s investment into growth and reproduction. Pogonomyrmex harvester ants store vast quantities of seeds in their nests that are thought to buffer the ants when external resources are not available. This research uses externally controlled food availability to examine how resource shortage affects colony investment, resource use, and resource distribution within the nest. Colonies were either starved or supplemented with resources for 2 months, beginning at the onset of reproductive investment and ending immediately before nuptial flights. Fed colonies invested more in overall production, proportionally more in reproduction relative to growth and in female reproductives relative to males. Stored seeds in starved colonies did not buffer production in this study. However, worker fat reserves were depleted in starved colonies, indicating that fat reserves fuel the spring bout of production. In starved colonies, worker fat reserves were depleted evenly throughout the nest, distributing the burden of starvation on all workers regardless of caste and age. A reallocation of diploid eggs into female workers rather than reproductives best explains the observed change in sex ratio investment between treatments. The redistribution of resources into growth relative to reproduction in starved colonies is consistent with life history theory for long-lived organisms, switching from current to future reproduction when resources are scarce.

Mating Flight Activity as Dealation Factors for Red Imported Fire Ant (Hymenoptera: Formicidae) Female Alates

Queens of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), release a primer pheromone that inhibits dealation (wing removal) of nestmate female alates by presumably suppressing endogenous concentrations of juvenile hormone (JH). Alates cast their wings once separated from the queen; however, the point of initiating dealation varies upon conditions. Alates are stimulated to shed their wings after several days of the death or removal of the queen, whereas newly mated alates dealate within 1 h after the mating flight. We found no single premating behavior or combination of behaviors associated with the nuptial flight that induces dealation rates comparable with that of newly mated queens. Copulation by itself or in conjunction with other behavioral signals and environmental prompts seems to be critical in causing rapid dealation in newly inseminated alates. In addition, colonies containing alates treated with precosene would not initiate mating flights nor could they be induced to fly. We suggest that precosene treatment affects the corpora allata (CA), but CA products other than juvenile hormone (JH) or in combination with JH are responsible for rapid dealation after mating. Dealation in the two contexts, within the colony and after mating flights, seems to occur via separate mechanisms.

First Recorded Mating Flight of the Hypogeic Ant,Acropyga epedana,with its Obligate Mutualist Mealybug,Rhizoecus colombiensis

On 26-July, 2005 a mating aggregation of Acropyga epedana Snelling (Hymenoptera: Formicidae) was observed in the Chiricahua Mountains in south-eastern Arizona. This is the first record of a mating flight of A. epedana, the only nearctic member of this pantropical genus. Mating behavior was observed, newly mated queens were collected, and a complete colony was excavated. New information is reported on the natural history and mating behavior of the species. The identity of a mealybug mutualist, Rhizoecus colombiensis (Homoptera: Rhizoecinae) is confirmed. Reproductive females participating in flights all carried mealybugs between their mandibles, indicating a vertical transfer of mealybugs with their ant hosts. No captured foundresses survived long in captivity, most likely due to the death of their mealybugs. The colony excavated had a single queen, though polygyny is common in the genus. Nearly all workers within the nest were heavily parasitized by mites, although males or gynes were not parasitized. These natural history observations are discussed with regard to this poorly understood mutualistic relationship between Acropyga ants and their mealybug partners.

Prevalence of Thelohania solenopsae infected Solenopsis invicta newly mated queens within areas of differing social form distributions

Newly mated queens (NMQs) originating from monogyne red imported fire ant ( Solenopsis invicta) colonies and following a mating flight, initiate new colonies by sealing themselves in a nuptial chamber and relying solely on their own fat and crop reserves, as well as no longer needed wing muscles to rear their first workers (claustral colony foundation). This method of colony-founding is rarely successful for polygyne-derived NMQs, whose low weight critically limits the number of first workers they are able to produce. However, this observation may be confounded by the parasitic microsporidium, Thelohania solenopsae, thus far found to persist only in association with polygyne colonies. Infections of this microsporidium reduce the weight of female alates and may explain why polygyne NMQs are unlikely to successfully found colonies claustrally. NMQs collected following mating flights in Gainesville and Ocala, Florida were sorted by weight, checked for insemination and T. solenopsae infection. Insemination levels were greater than 90% for all weight classes at both collection sites and were not related to infection. Infection levels were lower in Gainesville than Ocala, averaging 1.67% and 14.14%, respectively. Polygyne-derived NMQs collected in Ocala, defined here as weighing ⩽12 mg (social form correctly assigned in 85% of samples examined by PCR), had the highest infection levels, 25.37% (17/67) in 2003 and 21.43% (6/28) in 2004. We conclude that infection by T. solenopsae cannot be completely responsible for the inability of polygyne NMQs to claustrally establish colonies.

Alate differentiation and compound-eye development in the dry-wood termite Neotermes koshunensis (Isoptera, Kalotermitidae)

In social insects, caste-specific characters develop in the postembryonic differentiation processes. However, the mechanisms of caste-specific organ development have yet to be elucidated. In order to obtain insights into the relationship between caste differentiation and the regulation of organ development, we determined the caste-developmental pathway and observed compound-eye development accompanying alate differentiation in the dry-wood termite, Neotermes koshunensis. As previously reported in other Neotermes, this species has a linear caste-developmental pathway, comprising six larval- and two nymphal-instar stages. Although the apparent eye formation occurs during the last nymphal stages, just prior to the imaginal molt, individuals possess eye primordia from the first larval-instar stage. The outer morphological structure of the eye was observed from the third larval-instar stage. The detailed differentiation of cells constituting ommatidia appeared to occur in relatively young larval instars (fourth stage), although the pigmentation of pigment cells and detailed structural formation of ommatidia occurred during the final stage of alate development, i.e., during the late second nymphal-instar stage. This suggests that eye development is arrested in the larval stages, and then resumed during the late nymphal stage to complete functional eye formation, which is required for nuptial flight. In comparison to major hemimetabolous insects, which possess functional compound eyes even at the first instar larva, this termite species shows the heterochronic shift in terms of compound-eye development.

Evidence for reproductive isolation between two colour morphs of cavity nesting honey bees (Apis) in south India

In south India there are two distinct colour morphs of cavity nesting honey bees: the yellow ‘Plain’ morph and the black ‘Hill’ morph which are collectively known as Apis cerana. We show that the Hill morph is associated with a widely distributed mitochondrial haplotype that is present throughout mainland populations of south east Asian A. cerana. In contrast, the Plain morph, which is apparently confined to low to moderate elevations in India and Sri Lanka, is associated with a unique mitochondrial haplotype that is not present in other cavity nesting honey bees. We further show that in a region of sympatry (Bangalore, Karnataka State) the drone mating flight times of the two colour morphs barely overlap. Combined, drone flight data and the complete separation of mitochondrial haplotypes suggest that the two morphs are reproductively isolated. The Plain morph is distinguished from the Hill morph by the first three abdominal tergites of the worker, which are completely yellow in the Plain morph, whereas in the Hill morph they are black or black with yellow patches. Although the two morphs are generally distinguishable in the field by overall colouration, microscopic examination of the first 3 abdominal tergites is preferred.

Energetics of newly‐mated queens and colony founding in the fungus‐gardening ants Cyphomyrmex rimosus and Trachymyrmex septentrionalis (Hymenoptera: Formicidae)

Abstract The energetics of colony founding is investigated in the fungus gardening ants (Attini) Trachymyrmex septentrionalis and Cyphomyrmex rimosus. Similar to most ants, inseminated queens of these two species found nests independently unaccompanied by workers (haplometrosis). Whereas most ant founding queens seal themselves in a chamber and do not feed when producing a brood entirely from metabolic stores (claustral founding), the majority of fungus gardening ants must forage during the founding phase (semiclaustral founding). Laboratory‐reared T. septentrionalis individuals comprise 84 dealate females collected after mating flights in June 2004. Twenty are immediately killed to obtain values for queen traits and another 20 after worker emergence for queen, fungus garden and worker traits. Cyphomyrmex rimosus comprise 22 dealate females collected in June 2005; ten of which are immediately killed and similarly prepared. Newly‐mated T. septentrionalis queens have 25% of their dry weight as fat; whereas newly‐mated C. rimosus queens contain 11% fat. These amounts are 50–75% less than most independently founding ant species. Trachymyrmex septentrionalis queens lose merely 5% of their energetic content during colony founding, whereas the total energetic content of their brood is more than three‐fold the amount lost by the queen. Incipient T. septentrionalis colonies produce approximately half as much ant biomass per gram of fungus garden as do mature colonies. Similar to most ants, T. septentrionalis produces minim workers that are approximately 40% lighter than workers from mature colonies. Regardless of their size, T. septentrionalis workers contain much lower fat than do workers of claustral species. These data indicate that fungus gardening is adaptive because colonies can produce much cheaper offspring, making colony investment much lower.

Early Emergence of Males in the Termite &lt;I&gt;Reticulitermes speratus&lt;/I&gt; (Isoptera: Rhinotermitidae): Protandry as a Side Effect of Sexual Size Dimorphism

The early emergence (protandry) of males is common in a variety of insects. Most studies to date have explained protandry as an adaptive reproductive strategy. Sexual selection favors males that emerge before females because this maximizes the number of encounters with females. However, protandry may be a side effect of female-biased sexual size dimorphism (SSD) because larger females need a longer developmental time than males. Despite the plausibility of the adaptive protandry hypothesis, determining whether protandry is adaptive or incidental is difficult because size and developmental time are interdependent. Female-biased SSD is a common trend among insects and has been most frequently attributed to fecundity selection favoring large females. Reticulitermes speratus Kolbe alates showed significant SSD with female alates that were consistently heavier than male alates. A significant tendency was observed that SSD increased as body size increased among the colonies. A sexual difference in eclosion timing should be disadvantageous in this termite species because male and female alates perform swarming (nuptial flight) synchronously. Alates of an early emerging sex must use reserve nutrition while they wait for eclosion of the other sex in the colony. Nevertheless, significant protandry was found in R. speratus, and this tendency was detected even at the molt of the earlier nymphal stage. Therefore, the early emergence of males in this termite species is clearly incidental protandry due to the SSD. The occurrence of incidental protandry or protogyny as a side effect of sexual size dimorphism may be as common as adaptive protandry.

Mating Flight Initiation and Nutritional Status (Protein and Lipid) of &lt;I&gt;Solenopsis invicta&lt;/I&gt; (Hymenoptera: Formicidae) Alates Infected with &lt;I&gt;Thelohania solenopsae&lt;/I&gt; (Microsporidia: Thelohaniidae)

Female alates of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), infected with Thelohania solenopsae Knell, Allen, and Hazard (Microsporidia: Thelohaniidae) were found to be significantly less likely to be among the early alates to initiate a mating flight. If a flight was initiated, the infected females were significantly more likely to initiate the flight later in comparison with uninfected alates. In addition, many infected female alates seemed not to fly as a significantly greater proportion of the remaining females. Furthermore, infected females exhibited a significantly reduced body weight and a significantly reduced lipid titer, in comparison with uninfected individuals. However, there was no difference between the infected and uninfected alates in the amount of soluble protein. These results suggest that the low-weight, late flying-infected females may be less likely to reach a male mating swarm and less likely to outcompete uninfected females in mating and dispersing. Last, if mated or not, upon landing, the infected females may less likely have the needed energy to initiate a colony.

Genetic caste determination in Pogonomyrmex harvester ants imposes costs during colony founding

Some populations of Pogonomyrmex harvester ants comprise genetically differentiated pairs of interbreeding lineages. Queens mate with males of their own and of the alternate lineage and produce pure-lineage offspring which develop into queens and inter-lineage offspring which develop into workers. Here we tested whether such genetic caste determination is associated with costs in terms of the ability to optimally allocate resources to the production of queens and workers. During the stage of colony founding, when only workers are produced, queens laid a high proportion of pure-lineage eggs but the large majority of these eggs failed to develop. As a consequence, the number of offspring produced by incipient colonies decreased linearly with the proportion of pure-lineage eggs laid by queens. Moreover, queens of the lineage most commonly represented in a given mating flight produced more pure-lineage eggs, in line with the view that they mate randomly with the two types of males and indiscriminately use their sperm. Altogether these results predict frequency-dependent selection on pairs of lineages because queens of the more common lineage will produce more pure-lineage eggs and their colonies be less successful during the stage of colony founding, which may be an important force maintaining the coexistence of pairs of lineages within populations.

Genetic Analysis of Colony and Population Structure of Three Introduced Populations of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae) in the Continental United States

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a major invasive pest species in many parts of the world. We compared the colony breeding system and population genetic structure in three introduced populations in the continental United States: Charleston, SC; City Park, New Orleans, LA; and Rutherford County, NC. Based on worker genotypes at 12 microsatellite loci, we found that colonies were mainly genetically distinct entities consisting of either simple families headed by monogamous pairs of reproductives or extended families containing multiple neotenic (replacement) reproductives descended from simple families. Populations varied from 48% simple families in Charleston to 82% simple families in City Park. Extended family colonies in all three populations were likely headed by <10 neotenic reproductives. There was no significant isolation by distance in any of the populations, suggesting that colonies reproduce by relatively long-range mating flights and/or human-mediated dispersal within each population. The Charleston population showed evidence of a recent genetic bottleneck and most likely was founded by very few colonies. Cluster analysis indicated that the Charleston and City Park populations are quite genetically distant from each other and most likely originated from different source populations. The more recently introduced Rutherford County population was genetically most similar to City Park. These findings, together with results from other infested sites, indicate considerable variation in the genetic structure and breeding system of introduced populations of this species, making it unlikely that there is a simple genetic or behavioral explanation for the success of C. formosanus as an invasive species.

Fundamental difference in life history traits of two species of Cataglyphis ants

BackgroundThe two sympatric species of Tunisian desert ants, Cataglyphis bicolor and C. mauritanica, do not exhibit any differences in their foraging ecology, e.g. in food preferences and in their spatial and temporal activity patterns. Here we show that instead the two species markedly differ in their life histories.ResultsWe analysed mtDNA of specimens that were collected along a 250-km transect. C. bicolor exhibited a genetically unstructured population (with the genetic and geographic distances among colonies not being correlated). On the contrary the populations of the polygynous C. mauritanica were clearly structured, i.e. exhibited a strong correlation between genetic and geographic distances. This difference is in accordance with large queen dispersal distances due to far-reaching mating flights in C. bicolor and small queen dispersal distances due to colony foundation by budding in C. mauritanica. Furthermore, wherever we found populations of both species to coexist within the same habitat, the habitat was used agriculturally. Mapping nest positions over periods of several years showed that plowing dramatically decreased the nest densities of either species.ConclusionWe conclude that owing to its greater queen dispersal potential C. bicolor might be more successful in quickly re-colonizing disturbed areas, while the slowly dispersing C. mauritanica could later out-compete C. bicolor by adopting its effective nest-budding strategy. According to this scenario the observed sympatry of the two species might be an intermediate stage in which faster colonization by one species and more powerful exploitation of space by the other species have somehow balanced each other out. In conclusion, C. bicolor and C. mauritanica represent an example where environmental disturbances in combination with different life histories might beget sympatry in congeneric species with overlapping niches.

Biological characterization of the obligate symbiosis between Acropyga sauteri Forel (Hymenoptera: Formicidae) and Eumyrmococcus smithii Silvestri (Hemiptera: Pseudococcidae: Rhizoecinae) on Okinawa Island, southern Japan

The ant Acropyga sauteri Forel has an obligate, mutualistic symbiosis with a mealybug, Eumyrmococcus smithii Silvestri, on Okinawa Island, southern Japan. The mealybugs live inside ant nests nearly all their lives, and the ants depend on them for food. Alate foundress queens carry mealybugs during their nuptial flights, using them to establish new colonies at new sites. However, important aspects of the symbiosis have not yet been elucidated. The present study characterizes the basic biology of the symbiosis and describes for the first time the morphologies of all growth stages of E. smithii. Our study suggests that E. smithii has only one nymphal stage, followed by a female pupal stage or male prepupal stage. Intensive sampling of ant nests across seasons showed that A. sauteri prefers nest sites 5–20 cm underground. Acropyga sauteri produced reproductive stages mainly in mid‐March or early April, and numbers of both ant workers and mealybugs increased from spring to summer. Experimental determination of colony identity with a method using nestmate recognition by ants suggested that each ant colony rarely has a perimeter greater than 30 cm, that the ants are monogynous, and that different ant colonies are densely aggregated along the root system of a plant, adjacent to each other but not interflowing. Both symbiotic partners were vulnerable to attacks by several common subaerial ant species following physical disturbance to their nests.