Ecology and field biology of two dominant Camponotus ants (Hymenoptera: Formicidae) in the Brazilian savannah

Camponotus renggeri and C. rufipes are very abundant in Brazilian cerrado savannah, where they feed extensively on liquid rewards and commonly associate with plants bearing extrafloral nectaries and honeydew-producing insects. Here, we provide a qualitative and quantitative field account on the natural history and ecology of these two ant species. The study was carried out in a cerrado reserve in south-eastern Brazil across a rainy/hot season (summer) and a dry/cold season (winter). The ants were found in two vegetation physiognomies: all nests of C. rufipes were located in the cerrado sensu stricto (scrub of shrubs and trees, 3–8 m tall), whereas C. renggeri occurred mostly in the cerradão (forest with more or less merging canopy, 10–12 m tall). Both species nested in fallen or erect dead trunks, as well as underground. In addition, C. rufipes built nests using dead plant material arranged or not around shrub bases. Colonies of C. rufipes were generally more populous than those of C. renggeri, and both species had colonies with more than one dealated queen. Both species were active mainly at night and foraged for resources near their nests, mainly extrafloral nectar and hemipteran honeydew (aphids and mealybugs). The average size of the home ranges of C. renggeri in cerrado sensu stricto and cerradão varied from ≈ 2.8 to 4.0 m² and apparently were not affected by season. In C. rufipes, however, foraging grounds in cerrado sensu stricto showed a twofold increase from dry/cold (≈ 4.5 m²) to rainy/hot season (≈ 9.8 m²). Our study highlights the importance of natural history data to understand the foraging ecology and role of these ants in cerrado savannah.     

Ants feeding on anal exudate from tortricid larvae: a new type of trophobiosis

A new type of trophobiosis between tortricid larvae of a hitherto unknown genus and species, and various ant species of the subfamilies Formicinae, Dolichoderinae and Myrmicinae, was found in Malaysia. The larvae live in silken shelters fixed to the leaves of bamboo. In response to mechanical stimuli from the ants, they discharge from the anus a liquid containing sugar and amino acids and/or protein. The tortricid is described as Semutophila saccharopa gen. nov., sp. nov.; a second species, S. susurra sp. nov., is described from New Guinea.     

Natural history and ecology of foraging of the Camponotus crassus Mayr, 1862 (Hymenoptera: Formicidae)

ABSTRACT

Ants are abundant in terrestrial ecosystems, especially in the Brazilian Cerrado, where they can play several roles at different levels of the food chain, including protection of plants against herbivores. Although there are many studies that evaluate the ant–plant interaction in the Cerrado, little is known about the natural history of most species of ants. Camponotus crassus Mayr, 1862, for example, is considered one of the main agents of plant biotic defence in Cerrado. But there are no studies specifically focused on this species, which hinders the understanding of how arthropod–plant interactions are structured in Cerrado. Here, we describe the natural history and ecology of the foraging of the C. crassus. We conducted the study from January 2013 to December 2014 in 10 quadrants of 40 m² to measure: the abundance, density and distribution of nests, location of the nests, the internal structure of the nests, the daily foraging of workers out of the nest, the food items they collect and the existence of territoriality and dominance of the workers on the soil and vegetation. We found 18 nests, 13 in the soil and 5 in hollow trunks on the ground with variable internal structures. The distribution of nests is aggregate, with density of 0.045 nests/m² and average distance of 3.73 m between nests. The foraging activity occurs on the daytime during the rainy and dry season. Extrafloral nectar and honeydew were the resources most collected, comprising 83.33% of the resources in the rainy period and 30% in the dry period. Camponotus crassus is a dominant species, especially on vegetation, although it also forages on the soil. This is the first study to evaluate in detail the natural history and foraging ecology of C. crassus, a diurnal, aggressive and territorial ant that mainly forage climbing onto the plants.     

Review and reclassification of Cataglyphis (Hymenoptera,Formicidae)

Exactly 100 years ago Forel made a misidentification of Cataglyphis viaticus as C. megalocolus, one of the most characteristic insects of North Africa. This farreaching error has influenced the systematics of the genus ever since. What really are the species of Cataglyphis? Cataglyphis is unique among formicine ants in that the morphology of the male genitalia is highly diverse: their characteristics are used for the differentiation of species groups and as a basis for postulated phylogenetic relationships within the genus. A synopsis, a key to the species-groups, and a full catalogue of all the available names are given. Of the 104 taxa currently recognized as valid, Cataglyphis albicans var. mixtus is a new combination, Cataglyphis cursor ssp. flavicornis is transferred to Alloformica, and Cataglyphis mauritanicus and Cataglyphis nigripes are given a new status. Camponotus phaenogaster is a new synonym, and Cataglyphis hispidus is a nomen nudum. A lectotype has been fixed for Cataglyphis savignyi.     

Effects of different ant species on the attendance of neighbouring hemipteran colonies and the outcomes for the host plant

Ants commonly participate simultaneously in mutualisms with honeydew-producing hemipterans and extrafloral nectar-bearing host plants. These interactions are based on the exchange of resources (honeydew and extrafloral nectar) for ant protection against natural enemies. The benefits may vary according to the species of ant interacting, and the outcomes for the host plant and hemipteran will depend on the results of the ant-plant-hemipteran relationship as a whole. We studied a plant-mealybug association with Camponotus crassus Mayr (Formicinae) and Ectatomma tuberculatum Olivier (Ectatomminae) in a Brazilian tropical savanna. We aimed to elucidate whether the frequency of visitation by different species of ants can be affected by neighbouring colonies of mealybugs, and whether these ant species influence the number of hemipterans in a different way. Furthermore, we intended to find out whether the interaction between ant and hemipteran has any effect on the proportion of fruit production or on the abundance of trophobiont and non-trophobiont herbivores, also influenced by the ant species. Our results show that neighbouring aggregations of mealybugs influenced the frequency of ant visitation and the ants affected the number of nymphs over time, with both positive results only for C. crassus. We also detected an indirect negative effect on proportion of fruit production and an increase in abundance of trophobiont and non-trophobiont herbivores in the presence of C. crassus-mealybug interaction. Thus, we provide further evidence that colonies of hemipterans interacting with ants can be beneficial for these herbivorous insects, but they are quite harmful to the host plant. Nevertheless, the outcomes can be highly conditional in relation to ant species.     

Comparison of natural histories and karyotypes of two closely related ant‐eating spiders,Zodarion hamatum and Z. italicum (Araneae,Zodariidae)

Based on morphological characters, two species of the genus Zodarion, Z. hamatum and Z. italicum, were placed into the italicum group. The aim of this study was to evaluate similarity of these two species in respect of various aspects of their natural history and karyotypes. Both species had similar phenological patterns, being univoltine, but some specimens reached adulthood the same year before winter. Both representatives had nocturnal activity and were able to capture various ant species. Zodarion hamatum seems to be specialized on Myrmicinae ants, and Z. italicum on Formicinae ants. Zodarion hamatum showed more agile predatory behaviour than Z. italicum presumably due to specialization on Myrmicinae ants, which have lower population density. Both species are generalized mimics of bicoloured (orange‐dark brown) ants, such as Lasius emarginatus; they performed similar courtship and mating. The two study species exhibited contrasting reproductive strategies. Zodarion hamatum spiders had higher fecundity than Z. italicum as a result of larger body size but Z. italicum had larger eggs than Z. hamatum. This is presumably an adaptation to different availability of prey ants. Both species had the same diploid chromosome number, sex chromosome system and pattern of X chromosome heteropycnosis in testes. Results support a very close relationship between these two Zodarion species.     

Ant–herbivore interactions in an extrafloral nectaried plant: are ants good plant guards against curculionid beetles?

Extrafloral nectary drinking ants are known as effective plant guards, but some herbivores may circumvent ant attacks by foraging on different plant parts or presenting adaptations to avoid ant predation. Here we experimentally investigated the effect of Camponotus blandus on the florivory of the extrafloral nectaried shrub Banisteriopsis malifolia; and a possible spatial segregation between ants and herbivores (leaves and flowers). Flower buds are attacked by Anthonomus weevils. Results revealed no significant influence of C. blandus on the reduction of florivory. Adult Anthonomus are hard-bodied and were immune to ant bites; larvae are endophytic, so protected from ants. Ants and adult beetles were concentrated in different plant parts (leaves and flowers, respectively) so restraining the probability of encounters. Our results indicate that the system C. blandus–Anthonomus–B. malifolia is not stable, as ants receive extrafloral nectar, but are unable to protect the plant against weevils.     

Aquatic Coleoptera from Pakistan: faunistic and zoogeographical contribution (Coleoptera: Gyrinidae: Dytiscidae: Hydrophilidae)

Records of 19 species and one subspecies of water beetles of four families: Gyrinidae (two species), Dytiscidae (seven species), Hydrophilidae (10 species), and Spercheidae (one subspecies) from Pakistan are listed, based on collected material. Four genera and 10 species are recorded from Pakistan for the first time. The newly recorded genera are: Patrus, Helochares, Sternolophus and Coelostoma. The newly recorded species are: Dineutus spinosus (Fabricius, 1781), Patrus haemorrhous (Régimbart, 1891), Copelatus freudei Guignot, 1955, Copelatus sp1, Copelatus sp2, Enochrus ater (Kuwert, 1888), Helochares anchoralis Sharp, 1890, Sternolophus rufipes (Fabricius, 1792), Paracymus aeneus (Germar, 1824) and Coelostoma stultum (Walker, 1858). Zoogeographic affinities of the recorded species are discussed. According to their current distribution, the 18 species known from Pakistan can be classified into five zoogeographical categories.     

The life cycle and natural history of the tropical aphid Cerataphis fransseni (Homoptera: Aphididae: Hormaphidinae), with reference to the evolution of host alternation in aphids

We describe the life cycle and general biology of the tropical cerataphidine aphid Cerataphis fransseni. We demonstrate that this aphid migrates between trees of Styrax benzoin and various species of palms; palm-feeding populations have previously been known as C. variabilis and C. palmae, which now become synonyms of C. fransseni. On S. benzoin the fundatrix induces a relatively simple gall which can contain >6000 aphids at maturity with a large number of reproductively sterile soldiers that protect the gall from predators. These galls are apparently produced throughout the year. Colonies on the secondary host plants, palms, are apparently obligately tended by ants whereas colonies within galls on Styrax are never tended by ants. We discuss the life cycle of this tropical aphid with respect to hypotheses for the evolution and maintenance of host alternation.     

Bionomics of the myrmecophilous oribatid mite Protoribates myrmecophilus (Acari: Oribatida) in the Oriental tropics

Behavioural interactions between the myrmecophilous oribatid mite Protoribates myrmecophilus and the host ant Myrmecina spp. are described and compared to those of Aribates javensis which shows a very specialized myrmecophily. The behaviour of P. myrmecophilous is similar to free-living oribatids: they can walk by themselves and can survive without ant attendance. In the ant nests, the mites are sometimes cared for by ants and they are brought by ants into a new nest site. Protoribates myrmecophilus is eaten by non-host species of Myrmecina. Protoribates myrmecophilus is a less specialized myrmecophilous oribatid species.     

Phoretic behaviour of Attacobius attarum (Roewer, 1935) (Araneae: Corinnidae: Corinninae) dispersion not associated with predation?

Attacobius attarum spiders exhibit a phoretic behaviour on the winged sexual of Atta leaf-cutting ants during their mating flight. However, it is unclear if this behaviour is for dispersion or to facilitate the predation of ants in the new colonies. A nest of Atta sexdens was monitored on the day of the mating flight, and the winged ants, as well as the spiders, were collected. The results obtained corroborate the hypothesis that phoretic behaviour is commonly used for dispersion of the spider A. attarum, predominantly females. Of these spiders, 64 individuals of A. attarium were collected, of which 62 were females (96.9%) and two were males (3.1%). Regarding the winged leaf-cutting ants sampled, 378 females and 361 males were collected, totaling 739 individuals. Of these, 64 individuals (8.7%) had a spider attached to its back for phoretic dispersal and none was observed on the queens after the nuptial flight. In our study, A. attarum females perform phoretic dispersal into the environment on winged leaf-cutting ants but do not settle in the new nests.     

British species of the parasitic cynipid-wasp genus Aegilips (Hymenoptera: Cynipoidea,Anacharitinae)

The British species of Aegilips are revised and a key to species is provided. Of the eight species previously described from Britain seven are synonymized under the name A. nitidula (Dalman). Three new species (A. atricornis, A. romseyensis and A. vena) are described. A neotype is designated for A. nitidula (Dalman) and lectotypes are designated for A. rufipes (Westwood), A fumipennis (Westwood) and A. dalmani Reinhard.     

A revision of the ant-like sac spider genus Apochinomma Pavesi 1881 (Araneae: Corinnidae) in the Afrotropical Region

The genus Apochinomma Pavesi, 1881 is revised in the Afrotropical Region. The male and female of the type species, A. formicaeforme Pavesi, 1881, are redescribed. Five new species are described: A. malkini sp. nov. (♂ ♀) from Nigeria, A. parva sp. nov. (♂) from Guineé, and A. tuberculata sp. nov. (♀) from the Ivory Coast in the A. formicaeforme species group, and A. decepta sp. nov. (♂ ♀) from South Africa and Mozambique, and A. elongata sp. nov. (♂) from Botswana, Malawi and Tanzania in the A. decepta species group. Another undescribed species, known only from juveniles, belongs to the latter species group. Members of the A. formicaeforme species group mimic Polyrhachis ants and are thought to be primarily arboreal, whereas the A. decepta species group has ground-dwelling or grass-dwelling representatives that mimic large ground-dwelling ponerine ants. A single case of A. formicaeforme feeding on its model, Polyrhachis gagates, is noted. http://www.zoobank.org/urn:lsid:zoobank.org:pub:04116235-B195-48B0-B27E-076DAF4F51FD     

A preliminary study of nest structure and composition of the weaver ant Polyrhachis (Cyrtomyrma) delecta (Hymenoptera: Formicidae)

Polyrhachis weaver ants build their nests from vegetation bound together using silk produced by their larvae. Here we provide a pilot study of the composition and the physical structure of three arboreal silk nests of Polyrhachis (Cyrtomyrma) delecta based on examination of three colonies. We found broadly similar nest architecture and size of the nests with each containing six or seven identifiable chambers, and describe the distribution of ants of different castes and life stages between them. We also note the construction of silk ‘girder’ structures, which spanned larger chambers, and we hypothesize that these provide additional strength to the internal nest structure. This study highlights the importance of more detailed investigation of the internal nest structure and composition in Polyrhachis, and other weaver ant species, which will help to develop our understanding of this specialized form of nest construction and nesting habits in a diverse group of ants.     

Predation on eggs of Schneider’s dwarf caiman,Paleosuchus trigonatus (Schneider, 1807), by armadillos and other predators

Nests of Schneider’s dwarf caiman, Paleosuchus trigonatus, were located in the forests around three streams that drain into the Xingu River, Brazilian Amazonia, in October 2014. Camera traps were installed at the edge of four nests to document predators and female parental care. At two nests, females unsuccessfully defended their nests against one or more giant armadillos, Priodontes maximus, and nine-banded armadillos, Dasypus novemcinctus. Both armadillo species responded to the attack by fleeing and returning on the opposite side of the nest by going around the tree under which the nest was located. Giant armadillos have never before been recorded consuming caiman eggs and their diet has been described as consisting mostly of ants and termites. Another species of armadillo, Cabassous unicinctus, was also registered digging into a nest and probably consuming eggs, though it is generally considered to be primarily insectivorous. A tayra (Eira barbara), lizard (Tupinambis teguixin) and coati (Nasua nasua) were also registered taking eggs from nests during the day, but we obtained no registers of nest defence by caimans during the day. The three nests were attacked after 60 days of incubation, when the eggs were well developed.     

Description of the biology and immature stages of Pagyris ulla (Hewitson) (Lepidoptera: Nymphalidae: Ithomiini) in the Colombian Andes

The biology and immature stages of Pagyris ulla (Hewitson, [1857]) (Lepidoptera: Nymphalidae: Ithomiini) are described for the first time. The species’ host plant is established to be Brugmansia candida Pers. (Solanaceae). The life cycle from eggs to adult under laboratory conditions and ambient temperature took approximately 47 days, and the larvae passed through five instars. The larvae are gregarious, feed at night, and rest during the day in nests made by joining leaves near the apex of the plant stem.     

A note on manna feeding by ants (Hymenoptera: Formicidae)

The production of manna is often associated with the feeding injuries of the coreid, Amorbus obscuricornis (Westwood) (Hemiptera: Coreidae). The manna produced as a result of the injuries caused by A. obscuricornis is extremely attractive to ants and it is often taken right from underneath feeding bugs. Observations of a number of Tasmanian ant species feeding upon eucalpyt manna, suggest that this substance is an important source of carbohydrate for the ants. The possible significance of manna secretion is considered.     

New species and records of Flabellifera from the Indian Ocean (Crustacea: Peracarida: Isopoda)

In this study of flabelliferan Isopoda from the Indian Ocean, 19 species are described as new, in 11 genera and two families: family Cirolanidae, Baharilana koloura, B. lira, Cirolana aldabrensis, C. mimulus, C. somalia, C. undata, Eurydice paxilli, and Metacirolana chemola; family Sphaeromatidae, Cassidinidea clarkae, Cymodoce fuscina, C. lirella, Dynamenella alveolata, D. remex, Heterodina (new genus), H. mccaini, Oxinasphaera brucei, O. furcata, O. tetrodon, Paracilicaea stauros, and Sphaeromopsis sulcifera. Diagnoses of the genera and species are provided, and keys to the Indian Ocean species of most of the genera are provided. The material comes primarily from Aldabra Atoll, the granitic Seychelles islands, Zanzibar Island, and Phuket in Thailand. A few miscellaneous samples from the South African Museum collections, and from the International Indian Ocean Expedition carried out in the mid‐1960s are included.     

Studies on the predatory biology of Oriental dacetine ants (Hymenoptera: Formicidae) II. Novel prey specialization in Pyramica benten

The predatory biology of the ant Pyramica benten, a short‐mandibulate form in the tribe Dacetini, Myrmicinae, was studied in the field and laboratory. Pyramica benten prefers disturbed habitats, where they hunt predominantly collembolans of Entomobryidae. Laboratory observation and experiments revealed that this ant hunted such entomobryids more efficiently than collembolans of Tomocelidae and Isotomidae. The hunting behaviour of the ants is characterized by their grabbing the prey near the mouthparts and ambushing without approaching the prey. Success in this stealthy hunting is most probably enhanced by luring the prey with body smearing using organic material. Strumigenys are closely related to Pyramica but they are long‐mandibulate forms. Both genera are speciose and specialized predators on Collembola. Coleoptera is another group that has evolved specialized predators on Collembola so these dacetines and the coleopterans are compared for their hunting tactics and species diversity.     

New information about the third stage larva and larval habitat of Microdon (Chymophila) bruchi Shannon, 1927 (Diptera,Syrphidae) from Argentina

ABSTRACT

In this paper, we provide new biological information about Microdon(Chymophila) bruchi Shannon, 1927. We present new records of M. bruchi in nests of Camponotus mus Roger, 1863 built inside Vitis vinifera L. plants from Argentina (Mendoza Province) and records of this species for Catamarca and Entre Ríos, Argentina. DNA barcodes and data on morphology and locomotion for third-stage larvae are provided. An identification key is also given to distinguish M. bruchi from other Neotropical species of Chymophila. We designate a lectotype for Microdon bruchi Shannon, 1927, and we consider Microdon argentinae Hull, 1937 a junior synonym of M. bruchi.

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