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Ectatomma opaciventre Roger is a species of ant whose prey includes species of flies, however, the behaviors employed by workers in their predation were not known. In this article, an ethogram of predation on larvae and adults of the fly Hermetia illucens L. by workers of E. opaciventre was elaborated. Individuals were collected from three E. opaciventre nests and later transferred to artificial nests. For each of them, live fly larvae and adults were offered. From the observations, in a context of predation, observed behaviors that had similar functions were grouped into categories, with four of them having been observed in predation on larvae and all eight in predation on adults. The larvae were not actually preyed on (the aggressive behavior performed by the ants appears to be related to nest defense), but the adult flies, in fact, served as food. [ABSTRACT FROM AUTHOR]

A diversity of arthropods (myrmecophiles) thrives within ant nests, many of them unmolested though some, such as the specialized Eucharitidae parasitoids, may cause direct damage to their hosts. Ants are known to discriminate between nestmates and non-nestmates, but whether they recognize the strength of a threat and their capacity to adjust their behavior accordingly have not been fully explored. We aimed to determine whether Ectatomma tuberculatum ants exhibited specific behavioral responses to potential or actual intruders posing different threats to the host colony and to contribute to an understanding of complex ant-eucharitid interactions. Behavioral responses differed significantly according to intruder type. Ants evicted intruders that represented a threat to the colony’s health (dead ants) or were not suitable as prey items (filter paper, eucharitid parasitoid wasps, non myrmecophilous adult weevils), but killed potential prey (weevil larvae, termites). The timing of detection was in accordance with the nature and size of the intruder: corpses (a potential source of contamination) were detected faster than any other intruder and transported to the refuse piles within 15 min. The structure and complexity of behavioral sequences differed among those intruders that were discarded. Workers not only recognized and discriminated between several distinct intruders but also adjusted their behavior to the type of intruder encountered. Our results confirm the previously documented recognition capabilities of E. tuberculatum workers and reveal a very fine-tuned intruder discrimination response. Colony-level prophylactic and hygienic behavioral responses through effective removal of inedible intruders appears to be the most general and flexible form of defense in ants against a diverse array of intruders. However, this generalized response to both potentially lethal and harmless intruders might have driven the evolution of ant-eucharitid interactions, opening a window for parasitoid attack and allowing adult parasitoid wasps to quickly leave the natal nest unharmed. [ABSTRACT FROM AUTHOR]

Social insect colonies are high-value foraging targets for insectivores, prompting the evolution of complex colony defensive adaptations as well as specialized foraging tactics in social insect predators. Predatory ants that forage on other social insects employ a diverse range of behaviors targeted at specific prey species. Here, we describe a solitary foraging strategy of the ant Ectatomma tuberculatum, on nest guards of the stingless bee Tetragonisca angustula. We observed multiple instances of E. tuberculatum ambushing and successfully capturing the hovering and standing guards of T. angustula near nest entrances. The unique hovering behavior of the guard caste of this bee species, an adaptation to frequent cleptoparasitism by other stingless bees, may make these guards particularly vulnerable to ground-based, ambush attacks by E. tuberculatum. Likewise, the behavior of the foraging ants appears to adaptively exploit the defensive formations and activity patterns of these bees. These observations suggest an adaptive and targeted predatory strategy aimed at gathering external guard bees as prey from these heavily fortified nests. [ABSTRACT FROM AUTHOR]

Ectatomma tuberculatum has one of the most toxic venoms known among ants but there is no detailed study on its characteristics. In light of this, knowing the venom’s chemical composition is of paramount importance in order to obtain information about the mechanisms of its components. Several bioactive molecules have already been identified in Hymenoptera venoms, i.e., proteins such as phospholipases, hyaluronidases, and proteinases, as well as peptides. Protein databases show that information on protein components of ant venoms has been recently growing exponentially. In this study, we have identified proteins from the venom of Ectatomma tuberculatum by means of 2D PAGE, followed by tandem nanochromatography with mass spectrometry. A total of 48 proteins were identified, of which 42 are involved in metabolic processes, transport, and structural support. Moreover, six of them show similarity with not yet characterized proteins. Nine proteins are related to the attack/defense or maintenance process of the colony (colony asepsis, conservation of venom constituents, venom diffusion on prey, paralysis of prey, alteration of homeostasis, and cellular toxicity). Our findings may contribute to the identification of new natural prototypes of molecules to be synthesized and used in several areas of pharmacology. [ABSTRACT FROM AUTHOR]

Nuclear mitochondrial (mt) paralogues ( numts) are non-functional fragments of mt DNA integrated into the nuclear genome that can overestimate the number of species in analyses based on mt DNA sequences. As numts have relatively slow mutation rates, they can pass undetected by conventional procedures such as inspecting for internal stop codons, indels or apparent polymorphism in chromatograms. Species boundaries based on mt DNA markers therefore require a thorough assessment of numts, especially in insects, where this phenomenon appears to be relatively frequent. Ectatomma ruidum is a widely distributed Neotropical ant species that is distributed from northern Mexico to northern Brazil. Previous behavioural and molecular evidence suggests that this species actually represents a composite taxon. Here we assessed the species boundaries in E. ruidum based on two mt ( COI, cyt b) and one nuclear (H3) marker, as well as on external morphology. Ancient and recent mt paralogues were detected in several specimens, although pre- PCR dilution of DNA template helped to recover most of the mt orthologues. Based on the congruence found between our species delineation obtained from the mt genealogies and the discriminated morphospecies, we propose that E. ruidum is actually composed of at least three species. Two of these species have a wide geographical distribution in the Neotropics, whereas the remaining one was restricted to localities situated near the Pacific coast in south-east Mexico. We also found extensive intra- and interspecific variation in the barcoding locus. Moreover, the nuclear evidence suggests the existence of hybrids between two of these species in Oaxaca, south-east Mexico. This study agrees with previous studies of other closely related animal taxa, which have revealed a complex evolutionary history and overlooked species diversity in the latter region. [ABSTRACT FROM AUTHOR]

A new list of ant species from the state of Oaxaca, southern Mexico, is presented. Eighteen species are reported for the first time from the state. The genera are: Acromyrmex Mayr, 1865; Atta Fabricius 1818; Camponotus Mayr, 1861; Cephalotes Latreille, 1802; Dorymyrmex Mayr, 1866; Ectatomma Smith 1858; Monomorium Mayr, 1855; Neoponera Emery, 1901; Odontomachus Latreille, 1804; Pheidole Westwood, 1839; Tapinoma Föerster, 1850; and Tetramorium (Pergande 1896). After this study, the total number of ant species recorded for Oaxaca was 108. [ABSTRACT FROM AUTHOR]

In the ant Ectatomma tuberculatum (Olivier 1792), workers have active ovaries and lay trophic eggs that are eaten by the queen and larvae. Vitellogenins are the main proteins found in the eggs of insects and are the source of nutrients for the embryo in the fertilized eggs and for adults in the trophic eggs. In social insects, vitellogenin titres vary between castes and affect reproductive social status, nursing, foraging, longevity, somatic maintenance, and immunity. In most insects, vitellogenin synthesis is mainly regulated by juvenile hormone. However, in non-reproductive worker ants, this relationship is poorly characterized. This study determined the effects of juvenile hormone on vitellogenin synthesis in non-reproductive E. tuberculatum workers. Juvenile hormone was topically applied onto workers, and the effect on vitellogenin synthesis in the fat body and vitellogenin titres in the haemolymph were analysed by ELISA and qPCR. Juvenile hormone downregulated protein synthesis and reduced vitellogenin titres in the haemolymph, suggesting that in workers of E. tuberculatum, juvenile hormone loses its gonadotrophic function. [ABSTRACT FROM AUTHOR]

Venoms from three poneromorph ant species ( Paraponera clavata , Ectatomma quadridens and Ectatomma tuberculatum ) were investigated for the growth inhibition of Gram-positive and Gram-negative bacteria. It was shown that the venom of E . quadridens and its peptide fraction in particular possess marked antibacterial action. Three linear antimicrobial peptides sharing low similarity to the well-known ponericin peptides were isolated from this ant venom by means of size-exclusion and reversed-phase chromatography. The peptides showed antimicrobial activity at low micromolar concentrations. Their primary structure was established by direct Edman sequencing in combination with mass spectrometry. The most active peptide designated ponericin-Q42 was chemically synthesized. Its secondary structure was investigated in aqueous and membrane-mimicking environment, and the peptide was shown to be partially helical already in water, which is unusual for short linear peptides. Analysis of its activity on different bacterial strains, human erythrocytes and chronic myelogenous leukemia K562 cells revealed that the peptide shows broad spectrum cytolytic activity at micromolar and submicromolar concentrations. Ponericin-Q42 also possesses weak toxic activity on flesh fly larvae with LD 50 of ∼105 μg/g. [ABSTRACT FROM AUTHOR]

Insect societies are characterized by a relatively sophisticated division of labor; they form tightly knit groups that must effectively exclude non-members from the colony. However, the Neotropical predatory ant Ectatomma tuberculatum can harbor several specific myrmecophiles and, in particular, various eucharitid parasitoid wasp species. Adult wasps eclose in the host nests and are removed by worker ants without harm. Previous observations suggest that only a few workers perform this task. To test this hypothesis, we introduced different types of intruders, live and dead, pentane-washed broad-nosed grain weevil individuals ( Caulophilus oryzae) and dead, pentane-washed eucharitids ( Dilocantha lachaudii), into laboratory colonies containing individually marked workers. We recorded all encounters and behaviors until the intruders were removed. Certain workers removed intruders more frequently than expected by chance. The number of encounters with an intruder was positively correlated with the number of removals performed by the workers. For each nest, a small group of workers was identified as specialized in intruder removal. A subset of very committed workers in the specialists group that performed up to 57% of removals qualified as hyperspecialists or elite workers. The behavioral sequences differed based on the type and condition of the intruder: the sequence was more complex and included numerous aggressive behaviors (mandibular strikes and attempts at stinging) when workers encountered a live weevil. In contrast, the behavioral sequences with dead, pentane-washed insects were characterized by numerous detections through contact that did not lead to rejection and by the intruders simply being seized and removed from the nest. Overall, the data show that the ants discriminated between live and pentane-washed intruders and adjusted their behavior accordingly. This is the first demonstration in ants of both behavioral specialization and hyperspecialization in intruder removal. [ABSTRACT FROM AUTHOR]

Cognitive abilities used by arthropods, particularly predators, when interacting in a natural context have been poorly studied. Two neotropical sympatric predators, the golden silk spider Nephila clavipes and the ectatommine ant Ectatomma tuberculatum, were observed in field conditions where their interactions occurred regularly due to the exploitation of the same patches of vegetation. Repeated presentations of E. tuberculatum workers ensnared in their web triggered a progressive decrease in the capture response of N. clavipes. All the spiders that stopped trying to catch the ant on the second and/or third trial were individuals that had been bitten during a previous trial. Behavioural tests in natural field conditions showed that after a single confrontation with ant biting, spiders were able to discriminate this kind of prey more quickly from a defenceless prey (fruit flies) and to selectively and completely suppress their catching response. This one-trial aversive learning was still effective after 24 h. Likewise, E. tuberculatum workers entangled once on a N. clavipes web and having succeeded in escaping, learned to escape more quickly, breaking through the web by preferentially cutting spiral threads (sticky traps) rather than radial threads (stronger structural unsticky components) or pursuing the cutting of radials but doing it more quickly. Both strategies, based on a one-trial learning capability, obviously minimize the number of physical encounters between the two powerful opponents and may enhance their fitness by diminishing the risk of potential injuries resulting from predatory interactions. [ABSTRACT FROM AUTHOR]

Among social parasites, workerless inquilines entirely depend on their host for survival and reproduction. They are usually close phylogenetic relatives of their host, which raises important questions about their evolutionary history and mechanisms of speciation at play. Here we present new findings on Ectatomma parasiticum, the only inquiline ant described in the Ectatomminae subfamily. Field data confirmed its rarity and local distribution in a facultative polygynous population of E. tuberculatum in Mexico. Genetic analyses demonstrated that the parasite is a sibling species of its host, from which it may have diverged recently. Polygyny is suggested to have favored the evolution of social parasite by sympatric speciation. Nevertheless, host workers from this population were able to discriminate parasites from their conspecifics. They treated the parasitic queens either as individuals of interest or as intruders, depending on their colonial origin, probably because of the peculiar chemical profile of the parasites and/or their reproductive status. We suggest that E. parasiticum could have conserved from its host sibling species the queen-specific substances that produce attracting and settling effect on workers, which, in return, would increase the probability to be detected. This hypothesis could explain the imperfect social integration of the parasite into host colonies. [ABSTRACT FROM AUTHOR]

Abstract: Workers of the ant species Ectatomma tuberculatum (Ectatomminae) have active ovaries and lay eggs that are eaten by the queen and larvae (trophic eggs). Vitellogenins are the main proteins found in the eggs of insects and are a source of nutrients. The aim of this study was to characterize the period of vitellogenin production in workers of E. tuberculatum. The vitellogenin was identified from queen and worker eggs by SDS-PAGE. Anti-vitellogenin antibodies were obtained and used to detect this protein in the fat body and haemolymph of workers at different ages. Vitellogenin from E. tuberculatum consists of two polypeptides of 31 and 156kDa. In the eggs of queens, the 156kDa polypeptide is cleaved into two subunits of 36 and 123kDa. The analysis of the haemolymph of workers showed that the secretion of vitellogenin varies with age. The secretion is initiated around the fifth day after emergence, with peak production from days 20 to 60, and stops around day 100. The variation in production is related to the different activities performed by the workers within the colony, suggesting that vitellogenin may have an important role in maintaining age polyethism. [Copyright &y& Elsevier]

Abstract: Composition and dynamics of ant communities may be influenced by highly specialized, specific parasitoids such as eucharitids. Yet, little is known about their prevalence in ant societies. Through systematic monthly excavation of ant nests, we evaluated the impact on the Neotropical ant Ectatomma tuberculatum of two eucharitid parasitoid species, Dilocantha lachaudii and Isomerala coronata, which simultaneously attack the same host populations in southern Mexico. Nearly 90% of all the nests collected through the year were parasitized, with an average of 13% ant pupae and 6.7% ant larvae parasitized by eucharitids, and an annual loss of 17% of the ant brood. Eucharitid prevalence among host nests was, however, very variable, and only some E. tuberculatum nests were severely weakened (100% of ant brood parasitized). Parasitism was highest during the dry season (January–March), just when the production of ant pupae was minimum: up to 50.6% of the ant pupae were destroyed in March. However, production of E. tuberculatum males and females occurred later (June–July), and the reproductive potential of the host colonies did not ultimately seem to be heavily affected by eucharitid parasitism. Differences in the seasonal timing of eucharitid attack and ant reproduction thus have the potential to modulate the impact of eucharitids on ants. Our results are discussed in the context of the impact of eucharitids upon E. tuberculatum colonies and their possible effect on the community structure of this potential biocontrol agent ant. [Copyright &y& Elsevier]

Inquilines, workerless social parasites, frequently show advanced adaptations to their parasitic life style that indicate a long co-evolutionary history with their host. Ectatomma parasiticum, the first inquiline described in the poneromorph group, usurps established colonies of E. tuberculatum and produces only sexuals. In laboratory colonies, parasites were specifically attacked by the host workers, showing a failure in their social integration. Social interactions were frequent between parasites and their hosts, especially antennation, interpreted as attempts to promote colonial odor transfer. Inquilines destroyed eggs laid by the other queens (67 out of 209 eggs laid), including conspecific parasites, which is unusual. Such partial integration into the host colony and potential parasite virulence argue for a recent evolution of social parasitism in E. tuberculatum. [ABSTRACT FROM AUTHOR]

Abstract  The question of the occurrence of nepotism in insect societies is central to inclusive fitness theory. Here we investigated the existence of nepotism in the facultative polygynous ant Ectatomma tuberculatum because various characteristics of this species may have favored the evolution of nepotistic behavior toward queens. We thus studied worker–queen care toward their mother queen vs. an unrelated unfamiliar queen, to determine if workers cared preferentially for their mother. Although we tried to facilitate the expression of nepotistic behaviors, we did not detect significant nepotism confirming the general trend of an absence of nepotism in social insects. We discuss about the specific causes that can explain the absence of nepotism in E. tuberculatum regarding the particular social organization of this species and its ecological dominance in the mosaic of arboreal ants. [ABSTRACT FROM AUTHOR]

Policing, i.e. all behaviours that prevent a nestmate from reproducing, is currently observed in social insects. It is presumed to have evolved to regulate potential conflicts generated by genetic asymmetries or to enhance colony efficiency by avoiding surplus reproductives and brood. In the ant, Ectatomma tuberculatum, individual queen fecundity was similar in monogynous and polygynous colonies issued from a Mexican population. Egg cannibalism, however, occurred in the polygynous colonies. The stealing and destruction of reproductive queen-laid eggs involved only nestmate queens, even if they were highly related. No queen appeared to monopolize reproduction in the polygynous colonies. But, the observed value of relatedness among workers differed from the expected value, suggesting an unequal sharing of reproduction between queens. We discussed whether the cannibalism of queen-laid eggs in E. tuberculatum results from a competition for reproduction among queens or if this phenomenon is related to constraints on nutritional resources. [ABSTRACT FROM AUTHOR]

The boll weevil (Anthonomus grandis Boheman) remains a devastating insect pest on cotton (Gossypium hirsutum C. Linnaeus), particularly where it has not been eradicated. Identifying and understanding the survival of overwintered boll weevils, when cotton is not available, is important in designing mitigation programs and controlling this insect pest, especially in areas where boll weevils are active all year. Many non-malvaceous taxa have been listed as possible overwintering adult food sources. The purpose of this research was to determine if pollen from three non-malvaceous taxa could be used as food sources for overwintering boll weevils in the Lower Rio Grande Valley of Texas, where weevils are active year-round and during cotton-free periods. The taxa are almond [Prunus dulcis (Mill.) D.A. Webb], melon (Cucumis melo C. Linnaeus subsp. melo), and pigweed (Amaranthus sp.), Furthermore, it was intended to determine the retention of these pollen types in the boll weevil gut. More weevils (84%) contained almond pollen when they had additional water than those (30%) that did not have additional water. Almond pollen was found in 100% of the examined weevils after 72 hours, and in 80% after 96 hours. Pigweed and melon pollen were never found after 48 hours. Overall, almond pollen was found in more weevils (96%) than pigweed (40%), or melon (12%). In addition, a greater number of almond pollen grains (539) were found than pigweed (41), or melon (21). This shows that these types of pollen were consumed, and could play a part in the survival of overwintering weevils. However, more research is needed to examine the nutritional value of these, and other, pollen grains for overwintering boll weevil survival, and to determine the length of time weevils can survive feeding on these pollen types. [ABSTRACT FROM AUTHOR]

Social parasites exploit the worker force of colonies of other social insects to rear their own young. Social parasitism occurs in several Hymenoptera and is particularly common in several tribes of the ant subfamilies Myrmicinae and Formicinae. Here, we document the occurrence of miniaturized queens (microgynes) in colonies of Ectatomma tuberculatum, an ant belonging to the subfamily Ectatomminae. Behavioral observations and genetic analyses show that microgynes concentrate their reproductive efforts almost exclusively on the production of sexual offspring (microgynes and males), whereas the regular, large queens (macrogynes) produce workers in addition to sexuals. According to mitochondrial and nuclear markers, gene flow between microgynes and macrogynes is extremely limited. Whereas the co-occurrence of microgynes and macrogynes in the related species Ectatomma ruidum constitutes an intraspecific polymorphism associated with alternative dispersal tactics, microgynes found in colonies of E. tuberculatum appear to be a distinct species and to represent the first case of social parasitism in the poneromorph subfamilies of ants. [ABSTRACT FROM AUTHOR]

This study reports new information on interactions between Ectatomma tuberculatum (Ponerinae) and Crematogaster limata parabiotica (Myrmicinae). Workers of these sympatric arboreal ant species forage on the same pioneer trees. Diurnally, Ectatomma preyed on Crematogaster workers that avoided overt aggression by respecting a ‘safe distance’. At night, Crematogaster initiated raids within the Ectatomma nests that they apparently left with their abdomen empty, then remained near the nest entrances where they successfully intercepted 75.2% of the returning Ectatomma foragers (N=322). Certain intercepted workers rapidly resumed their return trip. Others (39.1%) were stopped, explored and licked during a long time by the Crematogaster. Most of them were carrying between their mandibles a droplet of liquid food that was stolen. This relationship, that appears to be a typical case of interspecific cleptobiosis, whose expression varies during the daytime, demonstrates for the first time sugary-food robbing, instead of prey robbing, in ants. To cite this article: F.-J. Richard et al., C. R. Biologies 327 (2004). [Copyright &y& Elsevier]

Presents a study that examined the effects of routine late-season field operations on numbers of boll weevils captured in large-capacity pheromone traps. Comparison of the flat and cylindrical adhesive boll weevil, Anthonomus grandis grandis Boheman, pheromone traps with the Hercon trap during the late cotton-growing season; Materials and methods used; Results of the study.

Studies the foraging behavior in two species of Ectatomma. Orientation and timing of foraging; Spatiotemporal distribution of resources; Directional and temporal adjustments made by Ectatomma in response to differential foraging success.

Analyzes the effect of Ectatomma tuberculatum toxin on cell membranes. Containment of homologous polypeptide chains; Intracellular distribution of ectatomin; Determination of the amino acid sequence and spatial structure of the toxin.

Investigates the capacity of the primitive ant Ectatomma tuberculatum to discriminate between nestmate and alien conspecific larvae in choice situations in relation to worker's age, social status and early experience. Methodology of the study; Results; Discussion.

Social insects exhibit a great variability in their social organization, and this affects colony kin structure, relatedness among nest mates, and population genetic structure. In the mosaic of arboreal ants of neotropical habitats, mutually exclusive dominant ant species occupy different territories, and their nest distribution is spatially aggregated in patches influencing patterns of population genetic structure. In this study, we performed an analysis of the population and colony genetic structure of the facultative polygynous ant Ectatomma tuberculatum to investigate how the particular breeding and social system of this species can explain its ecological dominance in the mosaic. Within-nest genetic analysis revealed that relatedness between nest mate workers was significantly greater than zero (r = 0.30) with an effective number of queens per nest of Ne = 2.5–3, indicating that polygyny is functional in this species. Moreover, we found that queen number was highly variable, probably due to queen adoption events, leading to the prevalence of polygyny over monogyny. Finally, the strong population genetic structure and the significant isolation by distance suggested that both budding and polydomy take place in this species. The respective role of secondary polygyny, budding, and polydomy are then discussed in the context of the mosaic of arboreal ants, and we propose that this particular social organization ensures the ecological dominance of E. tuberculatum by optimizing the colonization of new available nesting sites and by increasing territory size. [ABSTRACT FROM AUTHOR]

The article presents an abstract of a research study that discusses the effect of the venom of ant toxins on cell membranes. The study was conducted particularly on two toxins called ectatomins (Et-1 and Et-2) obtained from the venom of Ectatomma tuberculazum ants. This study revealed that Et-1 more efficiently binds with Ca+2-channels compared to ectatomin Et-2.