Biological notes on a fungus-growing ant, Trachymyrmex cf. zeteki (Hymenoptera, Formicidae, Attini) attacked by a diverse community of parasitoid wasps (Hymenoptera, Diapriidae)

A number of wasps in the family Diapriidae, subfamily Diapriinae (Proctotrupoidea), are parasitoids that specialize on ant larvae. These wasps are abundant and diverse in the Neotropics, but little is known about their biology. We studied parasitism rates by an array of diapriine wasps that attack the larvae of fungus-growing ants, Trachymyrmex cf. zeteki, in a single population (near Gamboa, Panamá). Relatively little is known about the biology and natural history of these ants, so we also present data on colony size and nest architecture. We excavated 136 colonies in central Panamá from June to September 2006, and 20 nests from July 2009. We reared six wasp morphotypes; two of them in the genus Mimopriella Masner and Garcia, one Oxypria Kieffer, two Szelenyiopria Fabritius and one Acanthopria Ashmead. The mean intensity of larval parasitism per ant colony was 33.9% (2006), and its prevalence across all ant populations was 27.2% (2006 and 2009). Parasitism rates were not positively correlated with host colony size. A single case of super-parasitism was documented in which two Oxypria males were reared from the same host larva.     

New species and record of the genus Petalomium (Acari: Heterostigmatina: Neopygmephoridae) associated with ants (Hymenoptera: Formicoidea) from Iran

The mite Petalomium camponoti Hajiqanbar & Khaustov sp. n. (Acari: Prostigmata: Neopygmephoridae) is described based on females recovered from ants Camponotus buddhae Forel (Hymenoptera: Formicidae) which were collected from a nest located on heights near Shirvan city, northeastern Iran. We also found Petalomium gottrauxi Mahunka, 1977 associated with Camponotus aethiops Latreille from the same locality. These findings present the first record of the genus Petalomium Cross from Iran. A key to species of the genus Petalomium associated with ant genus Camponotus Mayr is presented and host range of the Petalomium is discussed.     

Biology, immature and adult morphology, and molecular characterization of a new species of the genus Entedon (Hymenoptera: Eulophidae) associated with the invasive pest Specularius impressithorax (Coleoptera: Chrysomelidae, Bruchinae) on Erythrina plants

Entedon erythrinae sp. n. (Hymenoptera: Eulophidae), a gregarious egg-larval endoparasitoid of the Erythrina bruchine Specularius impressithorax, an invasive pest of the coral tree seeds (Erythrina spp.), is described from the Hawaiian Islands and Africa (South Africa, Tanzania and Mozambique). The biology and morphology of preimaginal stages of this new species are described in details.It is remarkable that the early embryo of the parasitoid represents a mass of undifferentiated cells surrounded by a peculiar membrane formed by the peripheral enlarged polygonal cells. The young larva developing inside this membrane corresponds morphologically to the second instar of congeneric species. Various peculiarities of the parasitoid-host relationships in gregarious and solitary Entedon parasitoids are discussed. The DNA sequences of 28S D2 (nuclear), Cytochrome Oxidase I (COI, mitochondrial) and Cytochrome B (CytB, mitochondrial) genes are provided for this new species and compared with the sequences of some other Afrotropical and Palearctic species of the genus.     

Ants that associate with Lycaeninae butterfly larvae: diversity, ecology and biogeography

Abstract. Field data on associations of butterfly larvae with ants were collated for 435 species of the subfamily Lycaeninae to analyse patterns in the identity, diversity and ecology of attendant ants. Worldwide, members of at least fifty-three ant genera from six subfamilies associate with Lycaeninae larvae. All these ant genera also forage for other liquid carbohydrate food sources. Species of Crematogaster and Camponotus constitute by far the most important ant associates of Lycaeninae larvae. Diversity of butterfly–ant associations, as measured by Hurlbert rarefaction, is highest in the Oriental, Australian and Nearctic faunal regions, and lower in Africa and the Palaearctic. The Neotropical region could not be assessed separately due to paucity of data. Multiple regression analyses revealed that the number of Lycaeninae species associated with a particular ant genus in a facultatively mutualistic manner is largely determined by the ecological prevalence and geographical distribution, but does not correlate with species richness, of an ant genus. This opportunism is suggested to be the key variable supporting the geographically and taxonomically widespread occurrence of ant–caterpillar mutualism in the Lycaeninae. Obligate interactions are much more specific and almost exclusively involve ecologically dominant ants with long-lived colonies. Neither species richness nor geographical distribution of an ant genus are significant predictors. In such associations, the role of ants shifts from visitors to hosts, and patterns of host use and specificity resemble those known from inquiline ant guests.     

A comparative study of the relationship between host size and brood size in Apanteles spp. (Hymenoptera: Braconidae)

ABSTRACT. 1. Current models of insect oviposition predict that clutch size in parasitoids should correlate with host size, with a continuum from solitary species at one end to large gregarious broods at the other. This prediction is tested for the genus Apanteles (sensu lato).
2. The distribution of brood sizes in Apanteles is bimodal, with peaks at one (solitary species) and at about twenty (gregarious species).
3. Brood size of gregarious species correlates with host size, but when a measure of the total volume of a parasitoid brood is plotted against host size, solitary species do not lie on the same regression slope as gregarious species.
4. There is a relative shortage of gregarious species on small hosts, and a relative excess of solitary species on large hosts. Solitary species on large hosts do not fully consume the host resource.
5. The possible role of evolutionary constraints to adaptive progeny allocation in Apanteles is discussed.     

Do Herbivores Eavesdrop on Ant Chemical Communication to Avoid Predation?

Strong effects of predator chemical cues on prey are common in aquatic and marine ecosystems, but are thought to be rare in terrestrial systems and specifically for arthropods. For ants, herbivores are hypothesized to eavesdrop on ant chemical communication and thereby avoid predation or confrontation. Here I tested the effect of ant chemical cues on herbivore choice and herbivory. Using Margaridisa sp. flea beetles and leaves from the host tree (Conostegia xalapensis), I performed paired-leaf choice feeding experiments. Coating leaves with crushed ant liquids (Azteca instabilis), exposing leaves to ant patrolling prior to choice tests (A. instabilis and Camponotus textor) and comparing leaves from trees with and without A. instabilis nests resulted in more herbivores and herbivory on control (no ant-treatment) relative to ant-treatment leaves. In contrast to A. instabilis and C. textor, leaves previously patrolled by Solenopsis geminata had no difference in beetle number and damage compared to control leaves. Altering the time A. instabilis patrolled treatment leaves prior to choice tests (0-, 5-, 30-, 90-, 180-min.) revealed treatment effects were only statistically significant after 90- and 180-min. of prior leaf exposure. This study suggests, for two ecologically important and taxonomically diverse genera (Azteca and Camponotus), ant chemical cues have important effects on herbivores and that these effects may be widespread across the ant family. It suggests that the effect of chemical cues on herbivores may only appear after substantial previous ant activity has occurred on plant tissues. Furthermore, it supports the hypothesis that herbivores use ant chemical communication to avoid predation or confrontation with ants.     

Imprinting Effects on Host-selection Behavior of Slave-raiding Chalepoxenus muellerianus (Finzi) Workers (Hymenoptera: Formicidae)

Early experience is known to influence brood care behavior and to induce nesting preferences of several ant species. Scanty information is available with respect to imprinting effects on host selection of dulotic ants. In this paper we investigate host choice behavior of workers of the slave-making ant, Chalepoxenus muellerianus. As in a corresponding paper (Schumann & Buschinger 1994) on host specificity of C. muellerianus young queens during colony foundation, we demonstrate that a blend of innate factors and effects of early experience also influences host species selection of slave-raiding workers.     

First screening of bacterial communities of Microdon myrmicae and its ant host: do microbes facilitate the invasion of ant colonies by social parasites?

Many studies have highlighted how numerous bacteria provide their hosts essential nutrients or protection against pathogens, parasites and predators. Nevertheless, the role of symbiotic microorganisms in the interactions between social insects and their parasites is still poorly known. Microdon (Diptera, Syrphidae) is a peculiar fly genus whose larvae are able to successfully infiltrate ant colonies and feed upon the ant brood. Using high throughput 16S rRNA gene amplicon sequencing, we provide the first microbiome survey of Mi. myrmicae larvae and larvae and workers of its host, Myrmica scabrinodis, collected from two sites in England. We analyzed the microbiome of the external surface of the cuticle and the internal microbiome of the body separately. The results clearly show that the Mi. myrmicae microbiome significantly differs from that of its host, while no substantial dissimilarity was detected across the microbiome of ant workers and ant larvae. Microdon myrmicae microbiome varies across the two analyzed sites suggesting that bacteria communities of Mi. myrmicae are derived from the environment rather than by horizontal transmission between hosts and parasites. Families Streptococcaceae, Carnobacteriaceae and Rizhobiaceae are dominant in My. scabrinodis, and Spiroplasma is dominant in ant workers. Microbiome of Mi. myrmicae larvae is mainly characterized by the family Anaplasmataceae, with Wolbachia as predominant genus. Interestingly, we found Serratia within both Mi. myrmicae and Myrmica larvae. Bacteria of this genus are known to produce a family of pyrazines commonly involved in ant communication, which could play a role in Microdon/ant interaction.     

Molecular phylogenies reveal host-specific divergence of Ophiocordyceps unilateralis sensu lato following its host ants

Ophiocordyceps unilateralis (Hypocreales, Ascomycetes) is an entomopathogenic fungus specific to formicine ants (Formicinae, Hymenoptera). Previous works have shown that the carpenter ant Camponotus leonardi acts as the principal host with occasional infections of ants from the genus Polyrhachis (sister genus of Camponotus). Observations were made on the permanent plots of Mo Singto, Khao Yai National Park of Thailand according to which O. unilateralis was found to occur predominantly on three host species: C. leonardi, C. saundersi and P. furcata. Molecular phylogenies of the elongation factor 1-α and β-Tubulin genes indicate a separation of O. unilateralis samples into three clades, reflecting specificity to each of the three different ant species. Samples collected from P. furcata and from C. leonardi were found to form sister groups with samples from C. saundersi forming an outgroup to the latter. Additional samples collected from unidentified ant species of Camponotus and Polyrhachis were positioned as outgroups to those samples on identified species. These results demonstrate that O. unilateralis is clearly not a single phylogenetic species and comprises at least three species that are specific to different host ant species. These cryptic species may arise through recent events of speciation driven by their specificity to host ant species.     

Unexpected benefit of a social parasite for a key fitness component of its ant host

Numerous invertebrates inhabit social insect colonies, including the hoverfly genus Microdon, whose larvae typically live as brood predators. Formica lemani ant colonies apparently endure Microdon mutabilis infections over several years, despite losing a considerable fraction of young, and may even produce more gynes. We present a model for resource allocation within polygynous ant colonies, which assumes that whether an ant larva switches development into a worker or a gyne depends on the quantity of food received randomly from workers. Accordingly, Microdon predation promotes gyne development by increasing resource availability for surviving broods. Several model predictions are supported by empirical data. (i) Uninfected colonies seldom produce gynes. (ii) Infected colonies experience a short-lived peak in gyne production leading to a bimodal distribution in gyne production. (iii) Low brood : worker ratio is the critical mechanism controlling gyne production. (iv) Brood : worker ratio reduction must be substantial for increased gyne production to become noticeable.     

Effect of grazing intensity on the interaction between Shijimiaeoides divinus asonis (Matsumura, 1929) and its attendant ants

This study was carried out in the natural herbaceous grassland of Mt. Aso, which had been almost completely grazed, and which is subjected to routine grassland burning every spring (February or March) to conserve Shijimiaeoides divinus asonis (Matsumura, 1929). We clarify that ants protect the larvae of this butterfly and evaluate the effects of grazing intensity on the attendant ant population. The results obtained are summarized as follows: (i) Five species of attendant ant were identified, with the dominant species being Formica japonica (Motschulsky, 1866) and Camponotus japonicus (Mayr, 1866). (ii) The number of attendant ants decreased at night time; however, only one or two ants attended the larva until the following morning. (iii) Ten species of insect excluding ants and three species of spiders that approached the larva were recorded on the larval host‐plant. Formica japonica and C. japonicus fought off most newcomers of other insects including the natural enemies of these butterfly larvae. (iv) The number of ants in this butterfly habitat under regular grazing intensity was significantly higher than during low grazing intensity and non‐grazing periods. (v) A positive correlation was found between the number of attendant ants and the number of butterfly larvae on the host‐plant. We concluded that the interaction between this butterfly and attendant ants is one of facultative mutualism because the attendant ants protect the butterfly larva. Therefore, the numbers of this butterfly species may decrease if the number of attendant ants decreases due to the cessation of pasturage.     

Behavioral strategy of a lycaenid (Lepidoptera) caterpillar against aggressive ants in a Brazilian savanna

Myrmecophily is widespread in lycaenid butterflies, in which ants receive food resources and, in turn, protect caterpillars against natural enemies. This interaction ranges from obligate myrmecophily, in which immatures are invariably associated with ants and are dependent on ants for survival, and facultative myrmecophily, in which larvae are not dependent on ants for survival, but the presence of the latter may increase larvae survival. Lycaenids also include non-myrmecophilous butterflies, which do not have positive associations with ants and have developed strategies to avoid being attacked or preyed upon by them. In this study, we examined the relationship between the lycaenid Michaelus ira and two ant species associated with Distictella elongata (Bignoniaceae). This plant has extrafloral nectaries and is patrolled by Camponotus crassus and Ectatomma tuberculatum. Morphological analyses revealed that M. ira larvae have ant organs, such as dorsal nectary organs and perforated cupolas, structures associated with myrmecophily. We performed larval exposure experiments in the field, predicting that, in the absence of myrmecophily, the butterfly larva would present strategies to avoid ant attack. Results showed that larvae were attacked by both ant species. To escape ant molestation, larvae lived and fed inside silk-sealed D. elongata flower buds. We concluded that the M. ira bud-sheltering behavior was a defensive strategy against these ant species, while the dorsal nectary organs were apparently nonfunctional. Nonetheless, myrmecophily, in general, cannot be excluded in M. ira since relationships with other ant species may exist.     

Distribution,host specificity,and the potential for cryptic speciation in hoverfly Microdon myrmicae (Diptera: Syrphidae), a social parasite of Myrmica ants

1. In 2002 Microdon myrmicae, a social parasite of Myrmica ants, was taxonomically separated from Microdon mutabilis. The original study in the U.K. found Microdon myrmicae to be specific to one ant species, Myrmica scabrinodis, yet it became apparent that the range of Microdon myrmicae includes at least the western Palaearctic. 2. Current knowledge of the European distributions of both Microdon myrmicae and Microdon mutabilis in Europe is reviewed. Also, in detailed studies of two Polish populations, Microdon myrmicae was found to survive equally well with two Myrmica ant species. We examine, however, the possibility that this reflects the presence of two separate Microdon species, each connected to one species of Myrmica. 3. Forty populations of Microdon myrmicae and 37 populations of Microdon mutabilis are currently known in Europe. All the populations in central and southern Europe that were visited after the separation of the two species were identified as Microdon myrmicae, while Microdon mutabilis’ recognised range is now restricted to the British Isles and Scandinavia. Myrmica scabrinodis was found to host Microdon myrmicae in 26 out of 31 populations investigated. Four other Myrmica species were identified to the host Microdon myrmicae: Myrmica gallienii (eight populations), Myrmica rubra (four), Myrmica vandeli (one), and Myrmica sabuleti (one). Microdon myrmicae occurs in waterlogged grassland habitats, mainly of the ‘Molinietum’ type, resulting in a patchy distribution relative to its host ants. 4. In two populations Myrmica scabrinodis and Myrmica gallienii are both abundant and rear Microdon myrmicae in equal proportions. Microdon myrmicae pupae from Myrmica gallienii nests were heavier and the anterior respiratory organs were of significantly different shape. In contrast, the comparisons of Microdon myrmicae pupae among all other populations showed no significant differences, suggesting only one species throughout the European range.     

Fecundity and longevity of Argentine ant (Hymenoptera: Formicidae) queens in response to irradiation

Irradiation is a post‐harvest quarantine treatment option to control ants and other hitchhiker pests on fresh horticultural products traded between countries. As little is known about irradiation effects on ants, radiotolerance of the Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae: Dolichoderinae), was studied to determine a dose sufficient for its control. Queens collected from Buenos Aires, Argentina, were irradiated with 30, 60, 90 Gy or left untreated as controls, and then followed for 8 weeks to evaluate their survival and fecundity. Overall queen survival and brood viability decreased with increasing irradiation dose. The number of eggs was reduced by 50%, 69% and 56% in the 30, 60 and 90 Gy doses, respectively, compared with untreated control queens. The percentage of eggs that developed into larvae decreased from 41.1% in the control to 22.5%, 1.4%, and 0% in the 30, 60, and 90 Gy treatments, respectively. Thus, the number of larvae was reduced by 69% in the 30 Gy treatment compared with the control, only one larva was observed in the 60 Gy treatment, and none in the 90 Gy treatment. Only one pupa was observed in the 30 Gy treatment and none in the 60 and 90 Gy treatments during the 8‐week experiment. Queens irradiated with 60 and 90 Gy had significantly reduced longevity compared with queens treated with lower doses or untreated queens. Radiation dose ≥90 Gy stopped brood development in Argentine ant queens and should be sufficient as a phytosanitary treatment. The radiotolerance of Argentine ant appears to be similar to that of two other important invasive ants.     

Azteca Ants as Antiherbivore Agents of Tococa formicaria (Melastomataceae) in Brazilian Cerrado

Several ant species have been found associated with domatia of plant species of the genus Tococa (Melastomataceae). In the present study we investigated the relationships between Tococa formicaria Mart. and ants in the Cerrado (savanna-like vegetation) from central Brazil. We addressed questions about the utilisation of domatia by different ant species and their efficiency in reducing herbivory. We found 8 ant species in the domatia, with Azteca sp. 1 being present in 47.2% of the sampled individuals. The other species found were: Azteca sp. 2, Camponotus sp., Dolichoderus gr. diversus, Dolichoderus lutosus, Leptothorax sp., Oligomyrmex sp. and Linepithema sp. The dominance of Azteca sp. 1 was significantly higher in the larger individuals, with about 85% of individuals in the highest size class being occupied by this species. We performed experiments of attack to live baits (termites) on T. formicaria leaves and on leaves of control species (any other neighbouring plant species of similar size). The recruitment rates were significantly higher on T. formicaria leaves. We also showed that herbivory was significantly lower in T. formicaria individuals occupied by Azteca sp. 1 than in individuals occupied by other ant species. The results of this study may be considered as evidence to support the assumption of a mutualistic relationship through defence against herbivory between Azteca ants and T. formicaria.     

Formicitylenchus oregonensis n. g., n. sp. (Allantonematidae: Nematoda), the first tylenchid parasite of ants,with a review of nematodes described from ants

The first tylenchid parasite of ants, Formicitylenchus oregonensis n. g., n. sp., is described from a queen carpenter ant Camponotus vicinus Mayr in Western Oregon, USA. The new genus is characterised by the excretory pore anterior to the nerve-ring and rounded tails in the free-living adults, a stylet bearing basal thickenings in the free-living female, a smaller stylet lacking basal thickenings in the male and a short, crenulate leptoderan bursa. The mature parasitic female is light yellow and ovoviviparous. F. oregonensis n. sp. is closely related to members of Metaparasitylenchus Wachek, 1955, with species parasitising beetles living under bark or in rotten wood, a habitat similar to that of carpenter ants. However, males of Metaparasitylenchus are characterised by a fairly long tail with a broad peloderan bursa. It is suggested that this case of tylenchid parasitism in ants is an example of environmental host selection. A review of the described nematode parasites of ants is presented.     

The influence of brood type on activity cycles inLeptothorax allardycei (Hymenoptera: Faruicidae)

We investigated the effect that different categories of brood had on the production of periodic activity within artificial aggregates of the ant,Leptothorax allardycei. Colonies of this species exhibit periodic patterns of movement activity with a period of approximately 20–30 min. Artificial aggregates of this species show that periodic activity appears gradually as the number of workers in the aggregate increases to 15 workers. In addition, it has been noted that the presence of brood with the workers makes the periodic activity more pronounced. In this paper we investigate the effect that four categories of brood had on the periodic activity of worker ants. Eggs, small larvae, large larvae, and pupae were tested with four different-sized aggregates of workers. We hypothesized that brood care is responsible for the increase in periodic activity and therefore that larvae (which require more tending) would be more effective at increasing periodic activity than eggs or pupae. Contrary to our expectations, eggs and both size categories of larvae were equally effective in enhancing periodicity in our experimental aggregates. Pupae, in contrast, were completely ineffective at enhancing periodic activity. We discuss some possible reasons for the differential effects of eggs, larvae, and pupae on the behavior of worker ants.     

Nylanderia deceptrix sp. n., a new species of obligately socially parasitic formicine ant (Hymenoptera,Formicidae)

Obligately socially parasitic ants are social parasites that typically lack the sterile worker caste, and depend on the host species for survival and brood care. The genus Nylanderia has over 130 described species and subspecies, none of which, until this study, were known social parasites. Here we describe the first social parasite known in the genus, Nylanderia deceptrix. Aspects of the biology of the host species, Nylanderia parvula (Mayr 1870), and Nylanderia deceptrix are examined. The data from both the host and the parasite species are combined to better understand the host-parasite relationship.     

Effect of collect time on communities of epigaeic ants (Hymenoptera: Formicidae) in areas of Eucalyptus cloeziana and cerrado

This study aimed at evaluating the effect of collect time (day and night) on ant fauna attracted to baits in areas of Eucalyptus cloeziana (Myrtaceae) and cerrado. The ants were collected in Fazenda Boa Vista, Mannesmann Fi - El Florestal Ltda, Paineiras, Minas Gerais State. Eigthteen sample units were collected: 12 in E. cloezina and six in cerrado. Each sample unit consisted of three plots (25 x 35 m each). The plot consisted of 34 baits distributed in a grid pattern at 5 m intervals. The sampling was carried out in the diurnal and nocturnal period. The results obtained revealed that both type of vegetation (cerrado x Eucalyptus) and the collect time (day x night) had a significative influence on the epigaeic ant fauna. The ordination (DCA) indicated that collect time effect was more important to fauna structuration than the vegetation effect. Brachymyrmex sp.1, Brachymyrmex sp.2, Camponotus crassus Mayr, Camponotus rufipes (Fabricius), Cephalotes pusillus (Klug) and Ectatomma brunneum Smith were indicator species of nocturnal period, and Camponotus renggeri-Emery, Camponotus atriceps (Smith), Camponotus melanoticus Emery and Paratrechina sp.1 were indicators of nocturnal period.     

Gustatory synergism in ants mediates a species-specific symbiosis with lycaenid butterflies

Here we show that larvae of the lycaenid butterfly Niphanda fusca secrete droplets containing trehalose and glycine. These droplets attract the larva's host ants Camponotus japonicus, which collect and protect the larvae. We comparatively investigated gustatory preference for trehalose, glycine or a mixture of the two between host (C. japonicus) and non-host (Camponotus obscuripes) species of ants in behavioral and electrophysiological experiments. Glycine itself induced no taste sensation in either host or non-host ants. The mixture of trehalose plus glycine was chosen as much as pure trehalose by non-host ants. However, the host ants clearly preferred the mixture of trehalose plus glycine to trehalose alone. When we used sucrose instead of trehalose, the mixture of sucrose plus glycine was chosen as much as sucrose alone, in both species. These behavioral data are supported by the electrophysiological responsiveness to sugars and/or glycine in the sugar-taste receptor cells of the ants. Considering that lycaenid butterflies' secretions have species-specific compositions of sugar and amino acid; our results clearly showed that such species-specific compositions of larval secretions are precisely tuned to the feeding preferences of their host ant species, in which the feeding preferences are synergistically enhanced by amino acid.