Article

Seasonal and nocturnal periodicities in ant nuptial flights in the Tropics (Hymenoptera: Formicidae)

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Abstract

Nocturnal nuptial flights of ants were studied at Guaynabo and Guanica in the tropical island of Puerto Rico. A great proportion of the species had a high frequency of flights during the year with little seasonality in the frequency of flights. Flights were less frequent during the dry season. Nuptial flights at Guaynabo occurred mostly during the post-sunset (18:30-22:30) and pre-dawn (04:00-06:00) hours. Few flights occurred between these two periods. The number of flights was fewer and flights on the average smaller in size in the Guanica dry forest than at Guaynabo. There was little differentiation in the flight patterns of species belonging to the same genus. All-male flights were more common than all-female flights, but in some species the pattern was reversed. One-sex flights were commoner than flights in which both sexes were present. Usually more males were captured on a nuptial flight than females, but in some months or in some species the pattern was reversed. The lack of flight synchronization between the sexes results in a great loss of reproductive effort in most species. This lack of synchronization implies that mating success cannot be estimated by the relative abundance of queens and males in nests.

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... The few long-term studies available on the flight phenology of tropical ants deal predominantly with seasonal patterns (Kaspari et al., 2001a,b). The exception is the work of Torres et al. (2001), which presents the nocturnal periodicities of ant nuptial flights in the tropical island of Puerto Rico, using light traps inspected regularly throughout the year. ...
... Previous studies suggest that a considerable proportion of the ant species presents nocturnal nuptial flights (Kaspari et al., 2001a;Nascimento et al., 2004), and that this behavior could be a strategy to avoid diurnal predators and the risk of desiccation caused by high temperatures (Nascimento et al., 2011;Torres et al., 2001). Also, the crepuscular hours would be less windy than daylight hours, and therefore more favorable to the flight of small insects, as Table 2 Clustering of time of flight activity based on all available data based on unweighted arithmetic average and Jaccard (binnary) coefficient. ...
... In addition, our results suggest that species with thickest integument (i.e., Dorylinae, Myrmicinae, and Ponerinae ants in this study) may extend the flight period for several hours along the day, including the hottest periods, which might possibly be related to a higher ability to reduce water loss. Torres et al. (2001) also found that queens start to fly earlier in the day than males, and that could explain the low number of males in the pre-dawn period (04:00 to 06:00 h). ...
Article
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In this study we document for the first time flight patterns along a 24h time range for an ant assemblage in one of the most diverse ecosystems on Earth, the Brazilian Atlantic Forest. Malaise traps were used to analyze the diurnal nuptial flights of a Neotropical ant assemblage during five days. Traps captured 802 individuals, revealing a remarkably high diversity (42 ant species), with samples strongly male biased (1:22). Contrariwise to similar studies, we found only a small proportion of species engaged in nocturnal nuptial flights, with diurnal flights accounting for an impressive 95% of all ant flight activity recorded. For the 18 most common species, three ant groups could be identified regarding flight period: sunrise, sunset, and continuous flight activity. Similarity analyses, however, suggest that closely related time ranges of flight activity may actually not be continuous. Further, three species showed pulsed flight activity, at varied hours of the day. Two species of Hypoponera showed flight activity at different periods of the day, suggesting congeneric staggered nuptial flights. Our results match long-term studies of ant assemblages showing high diversity of flight phenologies in hyperdiverse tropical ant assemblages and provide the first data on the reproductive phenology for several Neotropical ant species.
... Price & Waser, 1998 ) and birds (e.g. Tryjanowski et al. , 2005 ), few studies of annual reproductive phenologies of entire ant assemblages exist, and the most comprehensive of those studies are from the tropics or subtropics ( Tschinkel, 1991; Kaspari et al. , 2001a ,b; Torres et al. , 2001 ). Key to beginning to understand patterns and constraints on the timing and mode of reproduction in ants is an understanding of the distribution of ant reproductive flights across space, time and species (e.g. ...
... With a few interesting exceptions, ant reproductive flights in this temperate system were concentrated in the months from late spring to early fall. In contrast with results from Panama ( Kaspari et al. , 2001a ), but similar to results from the more seasonal Puerto Rico ( Torres et al. , 2001 ) and the Polish Carpathians ( Woyciechowski, 1987 ), strong peaks in reproductive flights were detected, with peaks in terms of numbers of individuals during the early and late summer months and a hump shaped pattern of diversity through time, with the most species flying during the end of summer or early fall. Freezing temperatures are common at nearly all elevations throughout the winter in the GSMNP, and such temperatures undoubtedly make reproductive flights in winter unlikely to succeed. ...
... However, the differences in flight times among species were not due to the staggering of flights by congeners. Instead, as in Panama ( Kaspari et al. , 2001a ) and Puerto Rico ( Torres et al. , 2001 ), congeneric species tended to fly at similar rather than different times, and differences in flying times were primarily attributable to differences among genera. All Camponotus species, for example, tended to fly at the beginning of the summer, whereas Myrmica species tended to fly at the end of summer or in early fall. ...
Article
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.
... The lower atmosphere is populated by a diverse and temporally variable ant community structured by body size, mating strategy, and potentially other ecological drivers. Dozens or even hundreds of ant species may fly over a single location each month 45,56,57 . Queens of different species vary by four orders of magnitude in body weight 35 , fly at different times throughout the day and night 57 , and occur at altitudes ranging from ground level to hundreds of meters into the atmosphere, providing a diverse menu for aerial predators. ...
... Dozens or even hundreds of ant species may fly over a single location each month 45,56,57 . Queens of different species vary by four orders of magnitude in body weight 35 , fly at different times throughout the day and night 57 , and occur at altitudes ranging from ground level to hundreds of meters into the atmosphere, providing a diverse menu for aerial predators. Ant mating flights represent a large and steady flow of readily available energy and biomass from colonies on the ground to predators in the sky, and thereby link terrestrial and aerial food webs. ...
Conference Paper
Purple Martins (Progne subis) are one of North America’s most abundant and high-flying aerial insectivores. Because of the difficulty of observing atmospheric animal communities, however, little is known about Purple Martin foraging altitudes and prey choice. We developed lightweight altitude loggers and deployed them on nesting Purple Martins in southeast Oklahoma to measure their foraging altitudes. At the same time we used nest collars to monitor the prey items that logged parents delivered to nestlings. By combining altitude data with prey identity and abundance, we not only determined what insect prey the young Purple Martins ate, but also mapped where in the atmosphere the prey species occurred. Nesting Purple Martins in this population fed predominantly on mating swarms of social insects, in particular the invasive Red Imported Fire Ant (Solenopsis invicta). Winged fire ant queens and males—by far the most abundant prey item—were captured on 32% of Purple Martin foraging trips and made up 56% of the total prey items and 27% of the total prey biomass delivered to nestlings. Other social insects captured in large numbers were exotic honeybees (Apis mellifera), subterranean termites (Reticulitermes sp.), and several native ant species (Camponotus pennsylvanicus, Dorymyrmex flavus, Crematogaster laeviuscula). Some potential agricultural pests were also heavily preyed on (Leptoglossus leaf-footed bugs, Melanoplus grasshoppers, Tabanus horseflies). Our method provides a novel way to study insect flight altitudes and atmospheric predator-prey networks. In addition, by quantifying Purple Martins’ consumption of exotic species and agricultural pests, we take a crucial step towards calculating the ecosystem service value of these abundant aerial predators. Finally, mapping how Purple Martins use the atmosphere may prove useful in guiding the design or placement of human structures such as wind turbines and communication towers.
... Such studies are important, because the timing of nuptial flights determines the ability of a species to reproduce, find nest sites, and found new colonies. Although Kaspari et al. (2001) and Torres et al. (2001) ________________________ studied alate nuptial flights in Panama and Puerto Rico, respectively, and Dunn et al. (2007) in the Great Smoky Mountains National Park, this seems to be the first study of the seasonality of alate nuptial flights in Texas. ...
... Likewise, Markin et al. (1973) reported that growth of colonies of S. invicta occurred only during the months of April through October in Southern Mississippi, and Rhoades and Davis (1967) noted that nuptial flights of S. invicta occurred only when air temperatures were 24 to 32°C, a temperature range that approximately coincided with the mean temperature during May through October in College Station in 1979. In contrast, there is little seasonality in flights of alate ants in tropical areas where temperatures are more uniform and, on average, warmer than in temperate zones, except when moisture is limited ( Kaspari et al. 2001, Torres et al. 2001); moisture being necessary for soil excavation and colony foundation. Thus, temperature seems to be the primary limiting factor in Central Texas; with peak nuptial flights occurring during the summer months when foraging and growth by a colony are maximum, unless rainfall is insufficient, making conditions unfavorable for foundation of a new colony. ...
Article
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The inquiline oak gall wasp fauna emerged from agamic galls of Andricus quercuslaurinus Melika and Pujade-Villar, 2009, a dangerous pest for Quercus affinis Scheidw. and Q. laurina Humb. et Bonpl. forests in Mexico, was studied for the first time. Three species in the genus Synergus Hartig, 1840 (Synergini) were obtained from these galls: Synergus davisi (Beutenmüller, 1907), previously known only from the United States of America; Synergus estradae Pujade-Villar and Lobato-Vila, 2016, described from the state of Morelos (Mexico); and Synergus pseudofilicornis Lobato-Vila and Pujade-Villar n. sp., so far determined as Synergus filicornis Cameron, 1883 (= Synergus furnessana Weld, 1913) and here considered as a new species. Synergus pseudofilicornis n. sp. is described and illustrated. A redescription and photographs of S. davisi, as well as new distributions and host associations of S. davisi and S. estradae, are given. The value of the inquilines as biological control agents for A. quercuslaurinus is discussed, and a preliminary list of parasitoids obtained from the galls is presented.
... The lower atmosphere is populated by a diverse and temporally variable ant community structured by body size, mating strategy, and potentially other ecological drivers. Dozens or even hundreds of ant species may fly over a single location each month 45,56,57 . Queens of different species vary by four orders of magnitude in body weight 35 , fly at different times throughout the day and night 57 , and occur at altitudes ranging from ground level to hundreds of meters into the atmosphere, providing a diverse menu for aerial predators. ...
... Dozens or even hundreds of ant species may fly over a single location each month 45,56,57 . Queens of different species vary by four orders of magnitude in body weight 35 , fly at different times throughout the day and night 57 , and occur at altitudes ranging from ground level to hundreds of meters into the atmosphere, providing a diverse menu for aerial predators. Ant mating flights represent a large and steady flow of readily available energy and biomass from colonies on the ground to predators in the sky, and thereby link terrestrial and aerial food webs. ...
Article
Full-text available
The atmosphere is populated by a diverse array of dispersing insects and their predators. We studied aerial insect communities by tracking the foraging altitudes of an avian insectivore, the Purple Martin (Progne subis). By attaching altitude loggers to nesting Purple Martins and collecting prey delivered to their nestlings, we determined the flight altitudes of ants and other insects. We then tested hypotheses relating ant body size and reproductive ecology to flight altitude. Purple Martins flew up to 1,889 meters above ground, and nestling provisioning trips ranged up to 922 meters. Insect communities were structured by body size such that species of all sizes flew near the ground but only light insects flew to the highest altitudes. Ant maximum flight altitudes decreased by 60% from the lightest to the heaviest species. Winged sexuals of social insects (ants, honey bees, and termites) dominated the Purple Martin diet, making up 88% of prey individuals and 45% of prey biomass. By transferring energy from terrestrial to aerial food webs, mating swarms of social insects play a substantial role in aerial ecosystems. Although we focus on Purple Martins and ants, our combined logger and diet method could be applied to a range of aerial organisms.
... Markin & Dillier 1971;Wuellner 2000), the Southeast Asian Camponotus gigas (Latreille, 1802) (Pfeiffer & Linsenmair 1997) and recently from Oecophylla smaragdina (Fabricius, 1775) in northern Australia (Nielsen et al. 2016). Some reports (mainly from the Neotropics) deal predominantly with flight phenology (e.g., Kaspari et al. 2001a, b;Torres et al. 2001;Feitosa et al. 2016), and revealed that the reproductive season of tropical ant species can vary from highly synchronous to nearly continuous throughout the year. In aseasonal perhumid tropical forests where the climate imposes no direct constraints on mating, the dispersal timing of queens may be related to the changing availability of nesting sites. ...
... Massive swarming flights perhaps occur due to the high predation risks during mating and dispersal of queens and/or to maximize mating success (Hölldober & Wilson 1990;Peters & Molet 2010). The advantage of year-long mating may come with the disadvantage of lower abundance of alates per swarming flight, requiring some common flight triggers (Torres et al. 2001). We did not find strict synchronization among our four directly observed study trees of M. bancana. ...
Article
Despite the great importance of nuptial flights for ants, little is known about the swarming processes from the highly diverse tropical regions, especially rainforests. This is particularly true for ants living in obligate symbiosis with myrmecophytic plants. Here we present the first direct observations of the swarming event in the association between Crematogaster captiosa and the pioneer tree Macaranga bancana in Southeast Asia. Nuptial flights of C. captiosa on M. bancana took place during the night, and alate females were seen to copulate with alate males on the tree. Data on C. captiosa from the Malay Peninsula as well as Borneo indicate that sexual production and colony founding occurs throughout the year. Despite episodic fruiting seasons of the host plants, Macaranga saplings for colony founding can also become available outside peak seasons from seed banks after disturbance. Therefore, continuous swarming might be a good strategy to avoid strong competition for limited nesting sites while still securing permanent colonisation of saplings - a prerequisite for their survival.
... At the extreme, mating opportunities are likely to be completely unpredictable in Dinoponera quadriceps Kempf, where females only start calling when the a-breeder (i.e., gamergate) has died or disappeared (Monnin & Peeters, 1998). Similar asynchronous phenologies are common among species in tropical forests (Kaspari et al., 2001a;Torres et al., 2001) and suggest either a continuous supply of free-living males searching for calling females, or continuous dispersal of ephemeral males from natal nests. ...
... (3) species where sexual workers (gamergates) attract foreign males to the nest (Haskins, 1978;Peeters & Crewe, 1986;Monnin & Peeters, 1998;Gobin et al., 2001); (4) colonies with non-flying (ergatoid) queens (Peeters & Molet, 2010;Peeters, 2012); and (5) species in tropical forests where asynchronous flight patterns are common (Kaspari et al., 2001b;Torres et al., 2001). It will be important to explore male trait convergence among FC species that have followed these varied evolutionary pathways. ...
Article
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An ant society, headed by a mated queen, can live for decades. Male ants, in contrast, are generally assumed to be ephemeral sperm delivery vessels programmed to die hours after leaving the nest to mate. However, the events from dispersal to mate location have rarely been studied, and the links between male traits and the ecological demands of diverse mating systems remain poorly understood. Here, we propose that interspecific variation in the length of mating flights has generated a life history continuum for male ants, and that the previously proposed ‘male aggregating’ and ‘female calling’ mating syndromes represent the endpoints. We also provide the first evidence for systematic divergence in pre-mating traits between males that attract females to brief nuptial swarms (Male aggregation syndrome) and those that must survive while searching for patchily distributed females that signal with pheromones (Female calling syndrome). Specifically, female-calling males tend to have larger eyes and mandibles, but the length of the basal antennal segment (scape) appears relatively constant across body sizes. After exploring these patterns, we review evidence that key components of fitness like mating frequency vary across a male life history continuum, and then explore links between male traits and a colony’s per capita reproductive investment. Systematic variation in pre-flight provisioning of males relative to mating systems may have important ecological implications, given that ants are dominant consumers on a global scale, and colonies ultimately use large fractions of harvested resources to fuel reproduction.
... Such studies are important, because the timing of nuptial flights determines the ability of a species to reproduce, find nest sites, and found new colonies. Although Kaspari et al. (2001) and Torres et al. (2001) ________________________ studied alate nuptial flights in Panama and Puerto Rico, respectively, and Dunn et al. (2007) in the Great Smoky Mountains National Park, this seems to be the first study of the seasonality of alate nuptial flights in Texas. ...
... Likewise, Markin et al. (1973) reported that growth of colonies of S. invicta occurred only during the months of April through October in Southern Mississippi, and Rhoades and Davis (1967) noted that nuptial flights of S. invicta occurred only when air temperatures were 24 to 32°C, a temperature range that approximately coincided with the mean temperature during May through October in College Station in 1979. In contrast, there is little seasonality in flights of alate ants in tropical areas where temperatures are more uniform and, on average, warmer than in temperate zones, except when moisture is limited ( Kaspari et al. 2001, Torres et al. 2001); moisture being necessary for soil excavation and colony foundation. Thus, temperature seems to be the primary limiting factor in Central Texas; with peak nuptial flights occurring during the summer months when foraging and growth by a colony are maximum, unless rainfall is insufficient, making conditions unfavorable for foundation of a new colony. ...
Article
Full-text available
Three species of Agromyzidae were identified at three municipalities in northern Sinaloa, Mexico. Photographs of adults, lateral and ventral aedeagus, and ejaculatory pump, as well as characteristic damage by the agromyzids on host plants were presented. Species identified were: 1. Liriomyza sativae Blanchard 1938 associated with Calendula sp., Carthamus tinctorius L., Helianthus annuus L., Lactuca sativa L., Parthenium sp., Tagetes erecta L., and Taraxacum officinale L., 2. Melanagromyza minima (Malloch 1913) associated with Wedelia sp., and 3. Melanagromyza splendida Frick 1953 boring stems of Carthamus tinctorius L. © 2018 Southwestern Entomological Society. All Rights Reserved.
... In the temperate regions of the Northern Hemisphere, mating flight occurs mainly in the warmer months, especially between the months of June and October, showing high synchrony among populations of the same species (Kannowski, 1961;Hölldobler, 1976;Gomez and Abril, 2012;Cantone, 2017Cantone, , 2018 [18,15,5] . In tropical regions, mating flight can occur all year round or during certain months, depending on the species (Kusnezov, 1962;Pfeiffer and Linsenmair 1997;Torres et al. 2000;Kaspari et al., 2001;Cantone, 2017Cantone, , 2018 [20,33,40,44] . Mating flight may occur at different hours of the day or night and is species-specific. ...
... In the temperate regions of the Northern Hemisphere, mating flight occurs mainly in the warmer months, especially between the months of June and October, showing high synchrony among populations of the same species (Kannowski, 1961;Hölldobler, 1976;Gomez and Abril, 2012;Cantone, 2017Cantone, , 2018 [18,15,5] . In tropical regions, mating flight can occur all year round or during certain months, depending on the species (Kusnezov, 1962;Pfeiffer and Linsenmair 1997;Torres et al. 2000;Kaspari et al., 2001;Cantone, 2017Cantone, , 2018 [20,33,40,44] . Mating flight may occur at different hours of the day or night and is species-specific. ...
Article
Full-text available
In the ants colonies of most species, the mating flight is carried out once or several times during the year, depending on the reproductive strategy and the environmental characteristics. Winged females and males ants, after leaving the nest, are subject to dangers posed by adverse climatic conditions and predators. Therefore, the species of ants have developed, in the course of their evolution, different mating flight strategies to avoid these dangers and synchronize flight with other colonies, so that individuals of the opposite sex have greater opportunity to meet. The process of urbanization fragment, degrade and isolates natural areas, depending on the density and urban and economic development form, by generating different profiles of urban landscapes. The objective of this study is to understand whether the environmental conditions, generated by different urbanization profiles, influence the mating flight of ants. Winged ants were captured daily over a two year period at two urban sites in the city of São Paulo, using light traps. Approximately 113,000 individuals were captured and assigned to eight subfamilies and 44 genera. At São Paulo city, in January, I recorded the largest number of ant genera in mating flight, probably associated with the maximum mean temperature values and the rainfall. The periodicity analysis of mating flight at subfamily and genera level shows different patterns between the two urban sites. I hypothesize that the trophic structure of ant communities reflects the dynamics of the trophic availability in different urban microhabitats showing, as a result, plasticity in the mating flight periodicity.
... The timing of nuptial flights and mating differs from just a few days for some Formica species (Klimetzek & Faas 1994) to throughout the whole year (Torres et al. 2001). Within warm *biomgn@biology.au.dk bs_bs_banner Austral Entomology (2015) ••, ••-•• climates, nuptial flights occur predominantly during the rainy seasons, whereas in temperate regions nuptial flights always occur during summer (Noordijk et al. 2008). ...
Article
The aim of this study was to elucidate the mating strategy of Oecophylla smaragdina (Fabricius, 1775) and to clarify the factors that related to the nuptial flight. The nuptial flight was investigated over three seasons in the Darwin area, Australia, in which a total of 19 swarmings were observed. All swarmings were observed on days where no rain fell before 15:00 h, and with wind speed ≤18 km/h. On days of swarming air pressure was significantly higher (mean ± SD: 1009.3 ± 1.6 hPa) than on rainless days without swarming (mean ± SD: 1006.9 ± 1.2 hPa). Several swarmings took place during the season, and the production of alate queens occurred more or less continuously over a period of at least 2 months. Therefore, the number of individuals in each swarming depends on the time elapsed since the last swarming. Swarming commenced with males gathering on the external surfaces of nests at sunrise, and about 15 min later they started departing, which took about 10 min. When the males commenced flying the females came out of the nests. When most males had flown, the females started flying, which also took about 10 min. Both males and females flew straight up towards an opening in the canopy. After swarming, alate queens were observed coming down to the canopy after 15–20 min. No queens were found in artificial queen traps 2 h after swarming. A few queens were observed flying around 13:00 h, and later in the afternoon many fertilised queens were found in queen traps. From field observation and laboratory experiments, we conclude that it is most plausible that alate queens meet the males in the air, proceed to the tree canopy to conclude the mating, and then after midday the mated alate queens fly individually to find a nesting site.
... This hypothesis is corroborated by Ketterl et al. (2003), who noted the presence of three species Downloaded by [ Heavy rains in the region during early September (Minuzzi et al. 2007) may lead to increased tree falls and the death of entire colonies inhabiting the extremities of dry twigs (Nakano, personal observation). Because the increased rainfall is also an important stimulus for the synchronized release of winged ants (Torres et al. 2001; Santos and Del Claro 2009), it is possible that upon falling in the leaf litter, the colony already contains breeders as well as workers and immature ants. Hence, in the early spring, a colony is able to release breeders that will colonize other environments, increasing the dispersal of the colony. ...
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The nests of Myrmelachista are found in tree trunk cavities and branches. The biology of these arboreal ants is still relatively unknown. We investigated the nesting behaviour of this genus in fallen dry twigs in the Atlantic rainforest of southeastern Brazil. Physical characteristics of the nests, colony demographics, presence of breeders and ant worker sizes were recorded. Samples were collected weekly for 12 months, along open, sunny and undisturbed trails within forest remnants. In all, 202 nests were collected and six species were recorded. Myrmelachista ruszkii had the highest population of immatures and the greatest number of nests found. Myrmelachista nodigera had the smallest workers, was the least populous and the colony was housed in the finest branches. These results expand the current knowledge about the diversity and biology of Myrmelachista in the Brazilian Atlantic forest, and describe polydomic nests and competitive behaviour of M. ruszkii.
... In this context, it was often hypothesised that species could stagger their reproduction. However in ants, closely related species tend to fly during the same periods, without staggering (Kaspari et al., 2001a,b; Torres et al., 2001; Dunn et al., 2007). Here, we hypothesised that, as in ants, the swarming period of termites is principally influenced by environmental factors, while other mechanisms preclude hybridisation between closely related species. ...
Article
During the last decade, many studies have focused on the diversity of termite species and their ecological function, but these have been mostly based on transect protocols not designed to sample canopy-dwelling and subterranean species. Additionally, all these studies relied upon collections of foraging parties composed of workers and soldiers in the soil or in pieces of wood. 2. We hypothesised that alate-based protocols could disclose spatial and temporal patterns of termite flights and provide a more balanced picture of assemblages for ecological and biodiversity surveys. 3. Our study took place in the framework of the IBISCA-Panama project, which used numerous trapping methods to give a multifaceted overview of a complex tropi- cal rainforest arthropod community. Two methods, flight interception traps and light traps, were efficient at collecting termite alates. All collected specimens were assigned to morphospecies which were later identified to the genus or species level, when possible. 4. Our results highlighted that: (i) alate trapping represents a powerful comple- ment to ground-based standardised sampling protocols by allowing the documenta- tion of the whole termite assemblage. (ii) Canopy dwellers fly preferentially in the upper strata, whereas no vertical stratification was found for ground dwellers, sug- gesting that height of flight is dictated by a pressure for long distance dispersal as well as the need to find a suitable site for colony-founding. (iii) Alates from closely related species do not stagger their flight period to avoid hybridisation but rather synchronise their flights according to environmental factors.
... Winged female and male sexuals were indeed found in P. cf. inversa colonies in our study population in March, September and November (unpublished observation), and whereas some founding colonies collected in March contained only eggs, others already had worker pupae or callows. Furthermore, several recent studies have documented that, in contrast to ants from boreal or temperate habitats, nuptial flights of many tropical ant species are not restricted to a short period of the year but may occur almost year-round (KASPARI et al. 2001, TORRES et al. 2001. Little is known of the reproductive biology of P. cf. inversa. ...
Article
Queens of the neotropical ponerine Pachycondyla cf. inversa may found their colonies co-operatively (pleometrosis) and still co-exist when the colony becomes mature (primary polygyny). We investigated the genetic structure of colonies from a Brazilian population by using microsatellites. In both queens and workers, inbreeding coefficients were significantly different from zero. No evidence for a geographical substructuring of the population was found. Heterozygote deficiency can probably be explained by a temporal substructure of the population, i.e. mating in temporally distinct mating swarms. Nestmate queens were typically not related. A comparison of the microsatellite genotypes of queens and workers indicated that some queens were multiply inseminated.
... Imposition or alteration of a periodic stimulus, such as a regular light-dark cycle, can cause the insect to rapidly adjust its activity cycle to resonate with the stimulus cycle (Fig. 3). A variety of animals can actively modify their temporal dynamics so that certain ecological events, such as egg hatch (Visser et al., 1998), migration (Froy et al., 2003), diapause (Musolin and Numata, 2003), foraging (Rydell et al., 1996) or mating (Torres et al., 2001), are more likely to occur at optimal times. Animals modify their cyclical patterns in response to specific, proximate cues from the environment, which are either directly associated or at least temporally synchronized with the ultimate events the animal is ''targeting.'' ...
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Agroecosystems contain complex networks of interacting organisms and these interaction webs are structured by the relative timing of key biological and ecological events. Recent intensification of land management and global changes in climate threaten to desynchronize the temporal structure of interaction webs and disrupt the provisioning of ecosystem services, such as biological control by natural enemies. It is therefore critical to recognize the central role of temporal dynamics in driving predator-prey interactions in agroecosystems. Specifically, ecological dynamics in crop fields routinely behave as periodic oscillations, or cycles. Familiar examples include phenological cycles, diel activity rhythms, and crop-management cycles. The relative timing and the degree of overlap among ecological cycles determine the nature and magnitude of the ecological interactions among organisms, and ultimately determine whether ecosystem services, such as biological control, can be provided. Additionally, the ecological dynamics in many cropping systems are characterized by a pattern of frequent disturbances due to management actions such as harvest, sowing and pesticide applications. These disturbance cycles cause agroecosystems to be dominated by dispersal and repopulation dynamics. However, they also serve as selective filters that regulate which animals can persist in agroecosystems over larger temporal scales. Here, we review key concepts and examples from the literature on temporal dynamics in ecological systems, and provide a framework to guide biological control strategies for sustainable pest management in a changing world.
... This dispersal strategy is corroborated by observations in the laboratory of intranidal mating and by the fact that queens were unable to establish new colonies in the absence of workers ( Ulloa-Chacón & Cherix 1990 ). Furthermore, workers have been observed moving winged queens on Santa Cruz Island in the Galápagos (Clark et al. 1982), and until recently nuptial flights of W. au-ropunctata had never been observed either in the field or laboratory (Spencer 1941; Sielberglied 1972; Lubin 1984;). Mating flights have been reported, however, among W. auropunctata populations in Puerto Rico (Torres et al. 2001). It is evident that there are still many gaps in our knowledge of the population biology of W. auropunctata, highlighting the need for continued monitoring in Marchena and further studies in its native and introduced range to better understand the mechanisms used for colony reproduction. ...
Article
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El desarrollo de técnicas efectivas para erradicar poblaciones de hormigas invasoras es esencial para la conservación de la biodiversidad nativa. Un programa intensivo fue iniciado en 2001 para erradicar la hormiga colorada invasora Wasmannia auropunctata (Roger), de un área de 21 ha en la Isla Marchena, Galápagos. Transectos lineales de aproximadamente 10 m entre cada uno, fueron hechos dentro de la vegetación del área infestada y en una zona de amortaguimiento de 6 ha. Amdro® (Hydramethylnon) fue aplicado manualmente hasta tres veces en el área de tratamiento a intervalos de tres meses entre marzo y octubre 2001. Hasta la fecha, se ha realizado cinco monitoreos para evaluar la eficacia del programa de erradicación colocando palitos pintados con mantequilla de maní en cuadriculas de 3-4 m. En abril y octubre 2002 se detectaron dos poblaciones pequeñas (0.1% del área ocupada originalmente por W. auropunctata) las cuales fueron tratados con Amdro®. No se encontró a W. auropunctata en Mayo 2003 y Abril 2004. Tampoco se encontró a la hormiga de fuego en cinco monitoreos nocturnos realizados en la zona de introducción de la hormiga. Los monitoreos continuarán por dos años adicionales para asegurar que no existen parches de hormigas y para verificar el éxito del programa. En este articulo se discute los procedimientos para erradicar W. auropunctata y para evaluar la eficacia de los métodos utilizados, los costos del programa y su aplicabilidad en otros ecosistemas isleños. Translation provided by the authors.
... In the 20 years since it was first collected in Florida, Technomyrmex difficilis has quickly expanded its range across a large portion of the state, and is now spreading across the West Indies. Torres et al. (2001) reported the earliest record of Technomyrmex (presumably T. difficilis ) from the West Indies, males collected in 1996 and 1997 in Guánica, Puerto Rico. Warner & Scheffrahn (2004) reported Technomyrmex collected in 2003 on Grand Cayman Island. ...
Article
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El Technomyrmex difficilis Forel es una hormiga del Mundo Antiguo que a menudo es mal identificada como la hormiga de patas blancas, Technomyrmex albipes (Smith). Los registros mas viejos de T. difficilis son del condado de Miami-Dade, Florida, recolectadas en el principio de 1986. Desde entonces, la hormiga ha sido encontrada en por lo menos 22 condados de la Florida. Aquí, informo de la presencia de T. difficilis en 5 islas del Caribe: Antigua, Nevis, Puerto Rico, St. Croix y St. Thomas. Las colonias solamente fueron muy exparcidas en St. Croix. Es probable que la importancia de T. difficilis como plaga va a aumentar durante los proximos años en la Florida y el Caribe.
... Furthermore, workers have been observed moving winged queens on Santa Cruz Island in the Galápagos (Clark et al. 1982), and until recently nuptial flights of W. au-ropunctata had never been observed either in the field or laboratory (Spencer 1941;Sielberglied 1972;Lubin 1984;Ulloa-Chacón 1990). Mating flights have been reported, however, among W. auropunctata populations in Puerto Rico (Torres et al. 2001). It is evident that there are still many gaps in our knowledge of the population biology of W. auropunctata, highlighting the need for continued monitoring in Marchena and further studies in its native and introduced range to better understand the mechanisms used for colony reproduction. ...
Article
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The development of effective techniques to eradicate populations of invasive ant species is crucial to the conservation of native biodiversity. An intensive program was initiated in 2001 to eradicate the invasive little fire ant, Wasmannia auropunctata (Roger) from approximately 21 ha on Marchena Island in the Galápagos Archipelago. Linear transects, approximately 10 m apart, were cut through the vegetation of the infested area and a buffer zone of 6 ha. Amdro (Hydramethylnon) was applied manually up to three times in the treatment area at three-month intervals between March and October 2001. To date, five follow-up monitoring surveys have placed sticks painted with peanut butter in a grid 3-4 m apart. Two small populations (0.1% of the area originally occupied by W. auropunctata) were detected in April and October 2002 and were subsequently treated with Amdro®. No W. auropunctata ants were found in May 2003 and April 2004. Five nocturnal surveys carried out in the immediate area of introduction of W. auropunctata did not detect any individuals. Monitoring surveys will continue for an additional two years to ensure eradication of any remaining populations and verify the success of this program. This paper discusses the procedures used to kill W. auropunctata and monitor the efficacy of the eradication methods, the program's costs, and its applicability to other island ecosystems.
... Cet auteur apporta des éléments de clarification pour séparer T. difficilis de T. albipes et considéra que tous les travaux publiés auparavant aux États-Unis faisaient référence au taxon T. difficilis. Dans les Caraïbes, elle avait été signalée pour la première fois en 2001 à Porto Rico (ToRRes et al., 2001) avec du matériel qui datait de 1996 et 1997. Par la suite, sa présence a été mentionnée dans les îles de Saint-Thomas, Sainte-Croix, Nevis et Antigua (WetteReR, 2008). ...
Article
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Nous mentionnons pour la première fois la Fourmi Technomyrmex difficilis (Forel, 1892) aux Antilles françaises, dans l'île de Saint-Barthélemy. Des caractères de diagnose morphologique permettant son identification d'après les critères définis par Bolton en 2007 sont présentés. Le séquençage d'une région de 650 paires de bases du gène mitochondrial codant pour la cytochrome oxidase 1 (CO1), proposée comme barcode standard chez les animaux, confirme l'identification spécifique des spécimens. Abstract. – Presence of Technomyrmex difficilis (Forel, 1892) in Saint-Barthélemy, French West Indies (Hymeno-ptera, Formicidae, Dolichoderinae). We report here for the first time the occurrence of the ant Technomyrmex difficilis (Forel, 1892) in Saint-Barthélemy, French West Indies. Morphological diagnostic characters which allow its identification according to the criteria defined by Bolton in 2007 are presented. Sequencing of a 650 base pairs region of the mitochondrial gene coding for cytochrome oxidase 1 (CO1), proposed as a standard barcode for the animal kingdom, confirms the specific identification of specimens.
... Finally, the time of day can play a significant role -for example, in many representatives of the genus Formica, nuptial flight occurs in the morning (with the exception of F. rufa, F. pratensis) (Ayre 1957;Ito & Imamura 1974;Kannowski 1959;Ueda & Komatsu 2014). In the tropics, the nuptial flight in many ant species are shifted to the dawn and pre-dawn hours (Torres et al. 2001); in nocturnal ant species, queens and males have a greater number of ommatidia compared to diurnal species, as was shown in leaf cutter ants (Moser et al. 2004). Nuptial flight in temperate latitudes can occur almost continuously, for at least a month (Myrmica rubra, M. scabrinodis -Woyciechowski 1987;Formica rufa, F. polyctena, F. lugubris, F. pratensis -Klimetzek & Faas 1994), with more or fewer winged alates, or for shorter periods (Myrmica lobicornis, Leptothorax nigriceps) (Woyciechowski 1987). ...
Article
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Based on the collected data set (758 observations for the period 2007-2021) on the dates of the nuptial flight for 73 species of ants, an analysis of possible time shifts due to global climate changes has been carried out. It was found that for Eastern Europe and Asia, for most species of ants, the dates of nuptial flight were shifted by at least two weeks earlier in comparison with the data for Western Europe. In a cold climate, there are significant changes, towards earlier dates, in the phenology of nuptial flight for two species: Lasius flavus (P<0.05) and Polyergus rufescens (P<0.01). The corresponding rates of change are 3.9 and 6.25 days per year. In other types of climate, no significant changes in the phenology of the nuptial flight were found. Taking into account the boundaries of future climatic zones in temperate and arid zones, such changes were recorded for several species. Solenopsis fugax in temperate climates shows a tendency to delay flight at a rate of 6 days per year (P<0.05). Within the predicted boundaries of the arid climate, the flight phenology delay was recorded for Lasius niger (5.8 days per year; P<0.01) and Messor sp. (4.4 days per year; P<0.05). At the same time, for Polyergus rufescens, there is a tendency to an earlier flight at a rate of eight days per year (P<0.05). No connection was found between the date of nuptial flight and the geographic distance between populations (or locations). ABSTRAK Berdasarkan set data yang dikumpulkan (758 pemerhatian dalam tempoh 2007-2021) ke atas masa penerbangan untuk pengawanan bagi 73 spesies semut, analisis perubahan masa yang disebabkan oleh isu pemanasan global telah dijalankan. Didapati kebanyakkan masa untuk Serangga 2022, 27(1): 152-179 Stukalyuk et al. ISSN 1394-5130 153 penerbangan pengawanan spesies semut dari Eropah Timur dan Asia telah berubah sekurang-kurangnya awal dua minggu berbanding dengan spesies dari Eropah Barat. Pada musim sejuk, terdapat perubahan signifikan terhadap tempoh masa awal ke atas fenologi untuk penerbangan pengawanan ke atas dua spesies; Lasius flavus (P<0.05) dan Polyergus rufescens (P<0.01). Kadar perubahan tersebut adalah 3.9 dan 6.25 hari per tahun. Pada musim lain, tiada perbezaan signifikan ke atas fenologi penerbangan pengawanan didapati. Dengan mengambil kira faktor sempadan pada zon iklim sederhana dan zon iklim gersang, beberapa perubahan direkodkan untuk beberapa spesies. Solenopsis fugax di zon iklim sederhana menunjukkan keupayaan untuk melewatkan penerbangan pada kadar enam hari per tahun (P<0.05). Dalam jangkaan sempadan pada zon iklim gersang, fenologi penerbangan direkodlan lewat ke atas Lasius niger (5.8 hari per tahun; P<0.01) dan Messor sp. (4.4 hari per tahun; P<0.05). Pada masa yang sama, Polyergus rufescens, berupaya untuk mempercepatkan penerbangannya pada kadar lapan hari per tahun (P<0.05). Tiada hubungan didapati di antara penerbangan pengawanan dan jarak geografi antara populasi (atau lokasi).
... It is an alternative for species for which the available nesting space seems to limit growth, but it is also related to an increase in foraging area (Santos and Del-Claro, 2009;Schmolke, 2009;Lanan et al., 2011) or to polygyny (Walin et al., 2001), which has been verified in P. gracilis and Nylanderia sp.1. The rains represent an important stimulus for the synchronized release of winged species (Torres et al., 2001;Santos and Del-Claro, 2009), but despite the field expeditions being conducted in months considered rainy (Minuzzi et al., 2007), few species were recorded as winged. The results indicate that Nylanderia sp.1 has a longer period of winged production, which can be a cause of the abundance of the genus in the tropics (LaPolla et al., 2011). ...
Article
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Ants can use twigs from fragments of tree branches as a nesting resource. The present study analyzed gatherings of ants in twigs of Albizia niopoides, a Fabaceae native to the Atlantic Forest that is used in landscaping in parks and squares in Brazil. Expeditions were performed in an urban park located in Atlantic Forest areas between February and June 2014. A total of 70 twigs with ants were collected and included 9357 workers, 2309 broods ants, 68 winged ants and 19 queens. Four subfamilies, 10 genera and 17 species/morphospecies were recorded. The species with the largest number of nests were Nylanderia sp.1, Hypoponera sp.4, and Wasmannia auropunctata. Ants of different species were found coexisting in the same twig, and Pheidole gr. tristis was the most common species found sharing a nest. Among the species recorded, only Pseudomyrmex gracilis and Pseudomyrmex phyllophilus are arboreal; the others also live in litter. For some species, our results indicate that the twig occupation in the litter can be structured and not by chance. No correlation was found between the twig structure and the colony components.
... The earliest record of T. difficilis in the West Indies was from Puerto Rico in 1996 (Torres & al. 2001 as Technomyrmex sp.). Since then, this species has quickly expanded its known range to sites scattered broadly across the entire West Indies region (Fig. 1). ...
... In consequence, males are selected to have longer reproductive lifespans than when mating occurs synchronously during one or a few days. Female sexuals may be present year-round in tropical ants [41,42] and over several weeks in many temperate Hymenoptera [43]. Individual males may leave their natal nest to search for and copulate with mating partners for several days or even weeks [25,37 ]. ...
Article
Perennial social insects are famous for the extraordinary longevity of their queens. While the lifespan of termite kings matches those of queens, males of social Hymenoptera are usually considered to die after one or a few copulations. While this is true in species with highly synchronized nuptial flights, in others males mate over much longer periods. Male longevity is not correlated with the life span of queens but appears to be adapted to mating opportunities. This is demonstrated by the extreme life span of Cardiocondyla ant males, which monopolize mating with virgin queens over many months. Cardiocondyla offers the opportunity to investigate why male longevity varies even among closely related taxa and how male age affects sperm and offspring quality.
... A produção de alados começa quando a colônia possui uma quantidade ótima de operárias para manter a alimentação extra aos imaturos que vão originar os reprodutores (KASPARI, 2003). Isso ocorre normalmente em períodos chuvosos (TORRES et al., 2001;KASPARI, 2003;DEL CLARO, 2009), o que é corroborado também para a região de estudo, exceto pelo mês de agosto (MINUZZI et al., 2007). Mas, neste mês ocorreu a menor liberação de alados. ...
... A produção de alados começa quando a colônia possui uma quantidade ótima de operárias para manter a alimentação extra aos imaturos que vão originar os reprodutores (KASPARI, 2003). Isso ocorre normalmente em períodos chuvosos (TORRES et al., 2001;KASPARI, 2003;DEL CLARO, 2009), o que é corroborado também para a região de estudo, exceto pelo mês de agosto (MINUZZI et al., 2007). Mas, neste mês ocorreu a menor liberação de alados. ...
... Newly emerged queens and males have wings and Torres et al. (2001) collected large numbers of W. auropunctata in light traps on Puerto Rico. However, such flights of males and females seem to occur only in the native range of W. auropunctata. ...
Technical Report
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There is a need to provide evidence-based assessments of the risks posed by invasive alien species (IAS) to underpin policies and prioritise action. Here we present the risk assessment for Wasmannia auropunctata. The risk assessments and associated management annexes were produced alongside tasks to develop and maintain a risk assessment template and to collect evidence on management techniques, implementation costs and cost-effectiveness. A two-day workshop was held to finalise the risk assessments following peer-review. The risk assessments will be used as evidence to inform whether the target species should be considered for inclusion on the list of invasive alien species of Union concern under Regulation (EU) 1143/2014 on the prevention and management of the introduction and spread of invasive alien species (the IAS Regulation).
... vironments, which they enter in vast numbers (markIn & al. 1971, morrIll 1974, kasParI & al. 2001a, torres & al. 2001, and where they are eaten by predators and thereby transfer energy, nutrients, and contaminants to aerial food webs (WHItComb & al. 1973, Helms & al. 2016a, Helms & tWeeDy 2017. I therefore supplement the terrestrial view by looking upward and emphasizing the roles ants play in the air above our heads. ...
Article
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Most of the world's ant species rely on flight for reproduction and dispersal, during a solitary phase in which colony fitness depends only on the survival of individual queens. Flight-related selection shapes ant physiology, such that queens and males fly for short durations but carry heavy loads due to the nutrient demands of mating and colony founding. Ants vary by four orders of magnitude in flight distance, with larger ants or those with lighter abdomens flying farther than smaller or heavier ones. Flight tradeoffs explain much variation in ant life history, including the temporal segregation of flight and egg production, the continuum of ant mating systems from male aggregation to female calling syndromes, and the evolution of alternate colony founding strategies. Flight performance also constrains range expansions or shifts in response to invasions or climate change. Flying queens and males act as dispersal vectors for pathogenic or symbiotic organisms, and are eaten in large numbers by aerial insectivores. By entering aerial food webs, flying ants help mediate the flow of energy and materials through ecosystems. They are also model systems for addressing several questions, including nutrient allocation tradeoffs and the evolution of reproductive polymorphisms.
... Fifth, in a study of ant nuptial flights in dry and moist environments, Torres et al. (2001) found that between 60 and 78 percent of over 30 species at the study locations engaged in nuptial flights, and do so often (average of four flights per night for all sites, time of day, and species combined), but those flights are generally dominated by a single sex, which raises issues about the reproductive strategies of the species involved. They found that flights were most common post sunset and pre-dawn with little activity between. ...
Article
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Juan A. Torres-Negron (Juan Torres) studied ants, wasps, termites and other insect groups. I reviewed 34 of his publications and grouped them into six subjects: ecological theory, taxonomy, chemistry, ecology, synthesis, and commentaries. Juan Torres used empirical fieldwork, keen observations, and experimentation to advance the understanding of ant taxonomy and ecology in Puerto Rico. His taxonomic work involved the description of new species and genera of various insect groups, as well as revisions of taxonomic groups, and other observations of the ecology and behavior of rare taxa. Juan Torres also published several taxonomic keys in English and Spanish for various insect groups and localities. His work with ant communities advanced ecological niche theory and island biogeography highlighting the non-equilibrium and stochastic nature of ant community dynamics in Puerto Rico and adjacent islands. He also published synthesis summaries of the ants of Puerto Rico, Mona Island, and the Luquillo Mountains. His ecological studies of ants ranged from descriptions of biotic interactions among ants and with other animal species, to the quantification of the role of insects in wood decomposition and nutrient cycling. The research spanned from dry to wet forest and non-forest conditions in Puerto Rico and adjacent islands and cays.
... Few species are totally arboreal. In addition, we did not detect the influence of dry or rainy months on the presence of winged in twigs, although the release of winged is related to the wetter season since rain is considered an important stimulus (Torres et al. 2001, Santos & Del-Claro 2009. ...
Article
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In the leaf litter, ants have various nesting resources available, such as live or dead trunks, twigs, leaves, fruits and seeds. On the twigs, there are adults and immature individuals, but also the queen and winged. The production of wings requires time and energy from the colony. The objective of this study was to investigate the presence of winged in ant colonies in twigs on the leaf litter. Our prediction is that the richness and abundance of winged in twigs are the greatest in rainy months. We collected all twigs with ants in 552 plots with 16 m2, totaling 8,832 m2 of leaf litter, in areas located in the Brazilian Atlantic Domain. We compared the species richness and the number of colonies with and without winged, as well as the number of winged over a year. In total, we collected 1,521 twigs with colonies belonging to 92 species of ants. The rate of twigs with winged was low, about 12%. In colonies with winged, the total number of twigs, species and amount of winged does not differ between the months considered dry and rainy. The majority of winged species are leaf litter dwellers, such as Linepithema neotropicum, recorded with the highest amount of winged irrespective of the period. Arboreal species colonized 15% of the twigs and, in 1/3 of these species, winged were recorded as part of the composition of the colony. Although winged represent a small percentage of the colony in twigs, our results indicate that this feature is important for the life cycle of 44% of the species that occupy twigs, considering that winged are fundamental for the dispersion of the colony.
Article
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Sexual reproduction can lead to major conflicts between sexes and within genomes. Here we report an extreme case of such conflicts in the little fire ant Wasmannia auropunctata. We found that sterile workers are produced by normal sexual reproduction, whereas daughter queens are invariably clonally produced. Because males usually develop from unfertilized maternal eggs in ants and other haplodiploid species, they normally achieve direct fitness only through diploid female offspring. Hence, although the clonal production of queens increases the queen's relatedness to reproductive daughters, it potentially reduces male reproductive success to zero. In an apparent response to this conflict between sexes, genetic analyses reveal that males reproduce clonally, most likely by eliminating the maternal half of the genome in diploid eggs. As a result, all sons have nuclear genomes identical to those of their father. The obligate clonal production of males and queens from individuals of the same sex effectively results in a complete separation of the male and female gene pools. These findings show that the haplodiploid sex-determination system provides grounds for the evolution of extraordinary genetic systems and new types of sexual conflict.
Article
A significant relatedness is of fundamental importance for the evolution and maintenance of social life (kin selection theory, Hamilton 1964a,b). Not only kin selection itself, but also more complex evolutionary theories make predictions on the occurrence of conflict and co-operation in animal societies. They all depend on the genetic relationships among individuals. Therefore, the study of unrelated, co-operating individuals provides a unique opportunity to critically test predictions based on these evolutionary theories. Using allozyme electrophoresis, the study species Pachycondyla villosa was found to represent three different species. Young queens in one of these species, provisionally called Pachycondyla cf. inversa, may co-operate during colony founding (pleometrosis). Approximately 50 per cent of all founding colonies collected near Itabuna, Brazil, consisted of two to five founding queens. Queens of P. cf. inversa have to forage for food (semi-claustral founding), and in founding associations only one queen specialised for this risky task. A microsatellite study showed that nestmate queens were typically not related. How can a division of labour be achieved, where one individual performs risky tasks to the favour of another individual to which it is not related? In contrast to the predictions made by group selectionists, this study provided clear evidence that the division of labour among co-foundresses of P. cf. inversa results from social competition: Co-foundresses displayed aggressive interactions and formed dominance hierarchies which predominantly served to force subordinates to forage. The frequency of queen antagonism increased with the duration since food was last added to the foraging arena. The social status was not, or only weakly associated with the reproductive status: As predicted by the reproductive skew theory, all foundresses laid eggs at similar rates, though the subordinate may be harassed during egg laying and occasionally, some of her eggs may be eaten by the dominant. The differential oophagy presumably was also reflected in a microsatellite study of foundress associations, which was conducted shortly after the first workers emerged: Here, the co-foundresses occasionally contributed unequally to the colony’s workers. Conflicts among workers or between workers and queens, e.g. over the division of labour or sex ratio, strongly depend on the genetic relationships among members of a colony. The number of two to five co-founding queens in polygynous colonies of P. cf. inversa, and the lack of relatedness among them, should lead to a decrease in the relatedness of workers. However, nestmate workers were closely related. Furthermore, worker relatedness may decrease as several queens were found to be multiply inseminated. Inbreeding coefficients were significantly different from zero in both queens and workers. No evidence for a geographical substructuring of the population was found. The deviation from random mating presumably was probably due to small, localised nuptial flights. Virgin queens do not mate near their natal nest and disperse before founding colonies. The analysis of cuticular hydrocarbons obtained from live queens revealed consistent differences between the patterns of cuticular hydrocarbons of queens with high vs. low rank: only high-ranking queens showed considerable amounts of cuticular pentadecane (n-C15) and heptadecene (n-C17:1). The presence of the two substances apparently was not associated with reproductive status. It is not yet known, if the two substances indeed serve to communicate high social status in P. cf. inversa. In experimentally assembled associations of two founding queens, queens engaged in aggressive interactions which already within one to twenty minutes resulted in stable dominance hierarchies. The queens attacking first usually won the contest and became dominant. Nest ownership at least for a couple of days did not influence the outcome of dominance interactions in the laboratory experiments, whereas queen body size apparently played an important role: In all eight trials, the larger queen became dominant. However, dominant queens from natural foundress associations were on average not larger than subordinates, suggesting that in the field, resident asymmetries might override size asymmetries only after a more prolonged period of nest ownership. Sequencing of the COI/COII region of mitochondrial DNA displayed sufficient variability for the study of the sociogenetic structure of the secondarily polygynous ant Pachycondyla obscuricornis: Six different haplotypes could be distinguished among six workers of different colonies from one study population in Costa Rica. The variability of other methods which were established (RFLPs, microsatellites, allozymes, and multilocus DNA fingerprinting) was too low for a further study on the genetic structure in P. obscuricornis. Die Verwandtschaft zwischen Individuen ist von fundamentaler Bedeutung für die Entstehung und Erhaltung sozialen Lebens (Verwandtenselektionstheorie, Hamilton 1964a,b). Nicht nur die Verwandtenselektionstheorie, sondern auch darauf aufbauende Modelle, die Vorhersagen über das Auftreten von Kooperation und Konflikten treffen, basieren auf den genetischen Beziehungen zwischen Individuen. Die Untersuchung von unverwandten, kooperierenden Individuen stellt somit eine einzigartige Möglichkeit dar, Vorhersagen dieser grundlegenden evolutionsbiologischen Modelle kritisch zu überprüfen. Mit Hilfe der Allozym-Elektrophorese wurde die neotropische Ameise Pachycondyla villosa in drei verschiedene Arten aufgeteilt. Bei einer dieser Arten, vorläufig als Pachycondyla cf. inversa bezeichnet, können Jungköniginnen nach dem Hochzeitsflug bei der Koloniegründung kooperieren. Die Hälfte aller Gründungs-kolonien, die in der Nähe von Itabuna, Bahia, in Brasilien gesammelt wurden, enthielten zwischen zwei und fünf Königinnen. P. cf. inversa Königinnen müssen in der Koloniegründungsphase auf Futtersuche gehen, wobei sich in Gründungsassoziationen immer eine Königin auf diese gefährliche Tätigkeit spezialisierte. Eine genetische Analyse von kooperierenden Königinnen mittels Mikrosatelliten konnte zeigen, dass diese nicht miteinander verwandt sind. Wie kann es zu einer Arbeitsteilung zwischen unverwandten Tieren kommen, bei denen ein Individuum sich zum Vorteil eines anderen verhält, mit dem es nicht verwandt ist? Im Unterschied zu Vorhersagen von Gruppenselektionisten, konnte in dieser Studie gezeigt werden, dass die Arbeitsteilung bei kooperierenden Königinnen auf Konkurrenz basiert: Aggressive Interaktionen führten zu der Ausbildung von Dominanzhierarchien, die vor allem die Arbeitsteilung beeinflussten. Dominante Individuen zwangen unterlegene, auf Futtersuche zu gehen. Der soziale Status eines Individuums war nicht, bzw. nur geringfügig mit dem reproduktiven Status assoziiert: Wie von der „reproductive skew“ Theorie postuliert, legten in den einzelnen Kolonien alle Gründungsköniginnen zu gleichen Anteilen Eier. Allerdings wurden unterlegene Tiere auch während der Eiablage attackiert, und in einigen Fällen wurden die Eier der unterlegenen Königin gefressen. Dieser selektive Eifraß spiegelte sich auch in einer Analyse der Genotypen von Arbeiterinnen und Königinnen mittels Mikrosatelliten wieder, die kurz nach dem Schlüpfen der ersten Arbeiterinnen durchgeführt wurde: In einigen Fällen produzierten kooperierende Königinnen eine unterschiedliche Anzahl von Nachkommen (Arbeiterinnen). Konflikte zwischen Arbeiterinnen oder zwischen Arbeiterinnen und Königinnen, z.B. über Arbeitsteilung bei den Arbeiterinnen oder die sex ratio, basieren auf den genetischen Beziehungen zwischen den einzelnen Individuen einer Kolonie. In P. cf. inversa müsste es durch die Anzahl von zwei bis fünf Königinnen in Gründungsassoziationen und deren fehlender Verwandtschaft zu einer ausgeprägten Reduktion des Verwandtschaftsgrades zwischen Arbeiterinnen kommen. Allerdings waren Arbeiterinnen recht eng miteinander verwandt. Zu einer Reduktion des Verwandtschaftsgrades zwischen Arbeiterinnen (in diesem Fall sogar innerhalb einzelner Matrilinien) führte außerdem, dass einzelne Königinnen mehrfach verpaart waren. In dieser Studie konnte ebenfalls gezeigt werden, dass die Inzuchtkoeffizienten (berechnet aus den Allelfrequenzen aus Königinnen und Arbeiterinnen) signifikant von Null unterschiedlich waren, wobei eine geographische Substrukturierung, Wahlund Effekte, oder Null-Allele als mögliche Ursachen ausgeschlossen wurden. Die positiven Inzuchtkoeffizienten sind wahrscheinlich eine Konsequenz von kleinen, örtlich begrenzten Paarungsflügen. Königinnen verpaaren sich dabei nicht in der Nähe des Mutternestes. Die Analyse kutikulärer Kohlenwasserstoffe lebender Königinnen zeigte eindeutige Unterschiede zwischen dominanten und unterlegenen Königinnen aus Gründungs-assoziationen von P. cf. inversa. Nur die Kutikula hochrangiger Königinnen wies größere Mengen an zwei Substanzen, Pentadecan (n-C15) und Heptadecen (n-C17:1), auf. Das Vorhandensein dieser Substanzen war dabei nicht vom reproduktiven Status des Tieres abhängig. Es konnte bislang noch nicht geklärt werden, ob die beiden Substanzen tatsächlich einen hohen sozialen Status mitteilen. In Kolonien, bei denen experimentell zwei Königinnen von P. cf. inversa zusammengesetzt wurden, kam es zu heftigen aggressiven Interaktionen. Innerhalb von 1 bis 20 Minuten waren stabile Dominanzverhältnisse erkennbar. Die Königin, die mit der ersten Attacke begonnen hatte, wurde das dominante Tier. Für die Ausbildung der Dominanzhierarchie spielte es keine Rolle, ob ein Individuum schon einige Tage länger in dem Nest war als das andere. Vielmehr war die Größe der Königinnen wichtig: in allen acht Versuchen wurde immer die größere dominant. Allerdings waren dominante Königinnen aus natürlichen Kolonien nicht signifikant größer als unterlegene. Im Freiland ist wahrscheinlich der Besitz eines Nestes für den Ausgang von Dominanzinteraktionen wichtiger als die Körpergröße der Königinnen. So könnten Königinnen, die bereits über einen längeren Zeitraum ein Nest bewohnen, dominant über neuankommende, frisch vermählte Weibchen werden. Für die Untersuchung der soziogenetischen Struktur einer sekundär polygynen Ameisenart, Pachycondyla obscuricornis, erwiesen sich Sequenzen mitochondrialer DNA (COI/COII) als ausreichend variabel: Sechs unterschiedliche Haplotypen konnten bei sechs Arbeiterinnen aus unterschiedlichen Kolonien einer Population unterschieden werden. Alle anderen Methoden, die für diese Art innerhalb dieser Doktorarbeit etabliert wurden (RFLPs, Mikrosatelliten-Analysen, Multilocus DNA Fingerprinting und Allozym-Elektrophorese) waren für eine weitere Untersuchung nicht ausreichend variabel.
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The 102 species of ants known to occur on the Archbold Biological Station in Highlands Co., Florida are listed with annotations on their habitat and microhabitat preferences and timing of nuptial flights. The diversity of the fauna results from the confluence of several biogeographic groups of ants. Several species are endemic to the xeric scrub of central Florida, which was an insular refugium during Pleistocene or Pliocene flooding. About 20 species are exotic, of which 6 have invaded scrub habitats. The invasibility of south Florida to exotic ants and the biogeographic affinities of native ants are discussed. /// Se registran las 102 especies de hormigas ya conocidas de la Estación Biológica Archbold en el condado Highlands en la Florida. Se presentan informaciones sobre el habitat y el microhabitat preferidos y sobre la sazón del vuelo nupcial. La diversidad de esa fauna resulta de la confluencia de varios grupos biogeográficos de hormigas. Algunas especies son endemicas del matorral xérico de la Florida central, que era un refugio insular durante inundaciones de la Pleistocene o Pliocene. Approximadamente 20 especies de esta fauna son exóticas, de las cuales 6 han colonizado el matorral xérico. Se trata de la invasibilidad de la Florida meridional por hormigas exoticas y de las afinides des biogeográficas de las hormigas nativas.
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Ants were studied on Puerto Rico and 44 islands surrounding Puerto Rico. Habitat diversity was the best predictor of the number of species per island and the distributions of species followed a nested subset pattern. The number of extinctions per island was low, approximately 1–2 extinctions per island in a period of 18 years, and the rates of colonization seem to be greater than the extinction rates. Ant dynamics on these islands do not seem to support the basic MacArthur and Wilson model of island biogeography. The MacArthur and Wilson equilibrium is based on the notion that species are interchangeable, but some extinctions and colonizations can change the composition and number of species drastically.
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In 1977, 1978, and 1979 nuptial flights of Lasius niger L., Lasius flavus F., Myrmica rubra L., and Myrmica scabrinodis Nyl. were observed on the island of Schiermonnikoog and in the area around Amsterdam. Weather conditions during these flights were determined using data from meteorological stations at Schiermonnikoog and Schiphol Airport. Significant differences were found concerning daytime, global radiation and relative humidity at the beginning of flights of Lasius niger, Lasius flavus, and Myrmica rubra; Myrmica scabrinodis had no defined preferences for these parameters. Wind velocity at 2 m of height was less than 1.7 m.s−1 during all flights before 20 August. After that date all species tended to fly at higher wind velocities as well. The calculated ranges for daytime, temperature, global radiation, relative humidity, and wind velocity appeared to be sufficient to characterize all nuptial flight occasions at Schiermonnikoog. Micrometeorological measurements in typical habitats of different ant species revealed that during flights the air temperature at 20 cm above ground and the soil temperature at 5 to 7 cm below ground were about equal in the habitat of the flying species, but unequal in the neighbouring habitats of coexisting ants.
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Alate broods are reared without worker broods in lower cavities of nests in winter, and with worker broods in upper cavities of nests in spring. Winged adults appear in early April, but swarming does not occur until late May. Flights issue yearly from most large nests. The alate sex ratio is about 1∶1. Before swarming will occur, nest surfaces must be soaked with at least 7 mm of rain; flights continue as long as nests remain wet and temperatures exceed 16°. A circadian rhythm triggers swarming at about 3∶55 a.m., and most alates leave the nest surface within 2 minutes. Fertilized females contain from 69 to 186 million spermatozoa. Seminal vesicles of males contain 65 to 130 million spermatozoa.
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Agricultural and grassland ants eat grain, liquid food or insects, or grow fungus; only liquid drinking and insectivorous ants occurred in the forest. Some species within food groups in the agricultural and grassland ants differed in size of food consumed or daily activity. Some species from agricultural land were restricted to different crops, but spatial microhabitat utilization contributed little to species separation. Forest species differed in their use of litter depths, daily activity and microhabitat. Results of interspecific aggression were influenced by priority effects and microclimate. Some species coexist by nonequilibrium processes or by stochastic events. -from Author
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Several species of the ant genus Cardiocondyla produce dimorphic males, which exhibit sharply different mating strategies. Winged males typically disperse to mate outside the nest, whereas wingless, ergatoid males stay in the nest and aggressively employ their mandibles against competing ergatoid males to monopolize the virgin queens eclosing in the nest. Such aggressive mating strategy would only be adaptive if the males had unlimited sperm supply. Histological studies showed that, contrary to the rule in the Hymenoptera order, the ergatoid Cardiocondyla males are indeed able to produce sperm during their entire adult life. Winged males, on the other hand, have only a limited sperm supply since spermatogenesis ceases in the late pupal stage.
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An extensive literature shows that astrocytes exhibit metabotropic glutamate receptor 5 (mGluR5)–dependent increases in cytosolic calcium ions (Ca2+) in response to glutamatergic transmission and, in turn, modulate neuronal activity by their Ca2+-dependent release of gliotransmitters. These findings, based on studies of young rodents, have led to the concept of the tripartite synapse, in which astrocytes actively participate in neurotransmission. Using genomic analysis, immunoelectron microscopy, and two-photon microscopy of astrocytic Ca2+ signaling in vivo, we found that astrocytic expression of mGluR5 is developmentally regulated and is undetectable after postnatal week 3. In contrast, mGluR3, whose activation inhibits adenylate cyclase but not calcium signaling, was expressed in astrocytes at all developmental stages. Neuroglial signaling in the adult brain may therefore occur in a manner fundamentally distinct from that exhibited during development.