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.     

Prey choice and raiding behaviour of the Ponerine ant Pachycondyla analis (Hymenoptera: Formicidae)

Termite raiding behaviour of the African poneromorph ant Pachycondyla analis was studied at Mpala, Kenya. In all, 330 raids were observed with the raiding activity showing peaks in the morning and evening. Time spent at the termite source was positively correlated with the numbers of termites taken. The sizes of foraging parties, number of termites taken, distance travelled and time spent at termite sources also showed a positive correlation. Pachycondyla analis preyed significantly more on Microtermes spp. than they did on Odontotermes spp. but no significant differences were found in terms of predator efficiency even though many ants were injured in raids on Odontotermes spp. compared with those on Microtermes spp. Our results indicate that P. analis seems to forage optimally, balancing the costs of energy with prey reward and prey choices were not only influenced by prey abundance, but also by the costs of foraging, as influenced by prey defences, size and foraging behaviour.     

A new Brazilian species of Heterothrips (Insecta: Thysanoptera) co-existing with ants in the flowers of Peixotoa tomentosa (Malpighiaceae)

Heterothrips peixotoa Del-Claro, Marullo and Mound is described as new. It has remarkably pale forewings, and lives in the flowers of a malpighiaceous shrub in Brazilian cerrado. The sepals of each flower are S-shaped and enclose a central cavity within which the thrips live and breed. Although some large ants are unable to penetrate this cavity, other ants are small enough to enter the space between the petals and sepals, and this leads to a reduction in thrips numbers. Several other members of this genus of thrips are known from the flowers of other species of Malpighiaceae.     

A new genus of dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) endemic to the Brazilian Atlantic Forest

ABSTRACT

A new genus of the tribe Deltochilini, Atlantemolanum new genus, endemic to the Atlantic Forest of Brazil, is proposed here to include two species formerly described in the genus Deltochilum based on the unique morphologic characters shared by Deltochilum riehli = Atlantemolanum riehli (Harold 1868) new combination and Deltochilum costalimai = Atlantemolanum costalimai (Pereira and D’Andretta 1955) new combination.

http://www.zoobank.org/urn:lsid:zoobank.org:act:7BBD89C3-2F23-4CEF-9560-C29695631E04     

Biogeographic analysis of the ant genus Gnamptogenys Roger in South-East Asia-Australasia (Hymenoptera: Formicidae: Ponerinae)

The distribution range of ants of the genus Gnamptogenys is analysed, with special reference to the Old World species, and two closely related genera: Rhytidoponera and Ectatomma. The study is based upon a cladistic biogeographic analysis, recognizing the following areas of endemism: Central America, South America, Philippine Islands, New Guinea, Australia, Solomons/Fiji and South-East Asia. These results are followed by a consensus of different information sources (phylogenetic, natural history, past and present distribution, palaeogeographical and palaeoclimatological) for explaining the present and past distribution of Gnamptogenys and related genera. The area cladogram shows repeated instances of sister relations between Old World and New World taxa at different depths within the tree. Subtree analysis further suggests a common sister relation between Gondwanan landmasses. The distribution of the Gnamptogenys is interpreted as a product of vicariance, starting with the separation of Gondwana, and subsequent dispersal into South-East Asia and Melanesia via rafting on the Australian craton. The desiccation of Australia during the Oligocene was detrimental to the presence of Gnamptogenys but favoured expansion of Rhytidoponera. The study illustrates that a cladistic biogeographic scenario may be supported by a consensus of data from various sources, and also suggests a pre-Tertiary diversification of ant fauna.     

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     

Polygyny,oviposition, life cycle and longevity of the three subspecies of leaf-cutting ants,Acromyrmex subterraneus (Hymenoptera: Formicidae)

ABSTRACT

Research related to the comparative biology of phylogenetically close ant species has received little attention, although it is the basis for understanding the systematics of some sibling groups. The objective was to study the polygyny, oviposition, life cycle and longevity of the three subspecies of leaf-cutting ants. For that, we studied: oviposition rate – queens from three colonies were individually placed in plastic containers, and at 24-hour intervals, the laid eggs were quantified over a period of 96 hours; the workers’ life cycle – the development of immature ants was observed every 24 hours and, as a result, the duration of each stage of development was determined; the workers’ longevity – newly emerged adults were tagged and returned to the fungus chamber of their respective nests, and daily observations were made in each of the nest’s chamber. Laying rates were variable in the three queens studied, with a mean of total eggs laid of 271 for Acromyrmex subterraneus brunneus, 113 for Acromyrmex subterraneus subterraneus and 119 for Acromyrmex subterraneus molestans.The incubation period was 21.2 days in A. s. brunneus, 22.8 days in A. s. subterraneus and 20.4 days in A. s. molestans. The larval phase and pupal phase lasted on average 22.5 and 21.2 days in A. s. brunneus, 22.8 and 15.8 days in A. s. subterraneus and 17.2 and 14.2 days in A. s. molestans, respectively. Life cycle was different in the studied taxa, from 62 to 77 days in A. s. brunneus, from 59–68 days in A. s. subterraneus and from 51 to 55 days in A. s. molestans. The workers’ longevity varied between subspecies A. s. brunneus, A. s. subterraneus and A. s. molestans.     

Deep sea swimming crabs of the Charybdis miles species group in the western Indian Ocean (Crustacea: Decapoda: Portunidae)

The deep-sea species of the Charybdis miles group occurring in the western Indian Ocean are revised on the basis of recent collections obtained by German and Russian expeditions. Two new species are described, Charybdis meteor sp. n. from the Straits of Bab el Mandeb and Charybdis crosnieri sp. n. from the insular margins and seamounts of the western Indian Ocean, which has been previously identified as Charybdis sagamiensis Parisi, 1916. The C. miles group represents a lineage with a probably relatively recent tendency for submergence which culminated in the formation of C. acutidens Türkay, 1986, a characteristic species of the deep Red Sea water mass.     

Breeding behaviour of Bokermannohyla nanuzae (Anura: Hylidae) at an Atlantic Forest site in southeastern Brazil

We studied the breeding activities of Bokermannohyla nanuzae at an Atlantic Forest site in southeastern Brazil from August 2010 to April 2012. We described courtship behaviour, acoustic parameters of calls, egg clutch features and the egg-laying site, and characterized the reproductive mode. We recorded calling males and gravid females almost year-round, except for a few months in the dry season. We observed the interaction of five male–female pairs that exhibited stereotyped behavioural sequences including visual and tactile signals. We identified three different types of calls that we considered as the advertisement call and two types of courtship calls. Egg clutches were placed in rocky crevices with water or in streamside puddles, among rocks, that would be likely to be flooded as stream water level raises, which characterizes a reproductive mode different from the one previously recognized for this species. The breeding biology of B. nanuzae is complex, with elaborate courtship behaviour and signalling.     

Observations on mermithid parasitism (Nematoda: Mermithidae) in two species of Lasius ants (Hymenoptera: Formicidae)

The morphological effects of nematode parasitism by Pheromermis myrmecophila were investigated in two species of ants, Lasius flavus and Lasius niger, collected on Clare Island, Ireland. Infected males and queens were found for L. flavus but only infected queens in L. niger. The numbers of nematodes present in each infected specimen were counted and their lengths were measured. Head width, femur length and wing measurements were made for infected and non-infected individuals of both species. In queens, the length of the nematodes decreased as the number per ant increased. When single nematodes were present their mean lengths were significantly greater in L. flavus than in L. niger. In addition to the reduction in wing size for all parasitized specimens, head widths and femur lengths of the queens were significantly different in both species. A log–log graph of radial cell length versus width suggested a linear reduction of wing size.     

Evolutionary trends in the reproductive biology of ponerine ants (Hymenoptera: Formicidae)

The colony sizes and ovariole numbers of eight ponerine, one cerapachyine and one doryline species are reported. The ergatoid queens of five of these species are described briefly. Workers of the Hypoponera, Leptogenys and Anochetus species entirely lack ovaries, the first report of obligate sterility in this subfamily. Three evolutionary trends in the reproductive biology of the Poneriae are discussed: an increase in ovariole numbers and specialization for reproduction in the queen caste; worker sterility and increasing reproductive differentiation between the castes; and the evolutionary loss of specialization for dispersal in ergatoid queens.     

Three new species of Laelaspis Berlese from Iran (Acari: Laelapidae), with a review of the species occurring in the Western Palaearctic Region

This paper reports on five species of mites of the genus Laelaspis associated with ants in Iran – Laelaspis astronomicus (Koch) from Tapinoma simrothi, Laelaspis equitans (Michael) from Messor sp. and Camponotus sp., Laelaspis kamalii Joharchi and Halliday sp. nov. from Tapinoma sp., Laelaspis pennatus Joharchi and Halliday sp. nov. from Tetramorium caespitum, and Laelaspis persicus Joharchi and Halliday sp. nov. from Pheidole pallidula. Laelaspis imitatus Reitblat has also been reported from Iran, in association with an unknown insect. A key to species of Laelaspis occurring in the Western Palaearctic Region is presented, with a summary of their host associations and biology.     

Microdistribution of juveniles and adults of the mud crab Panopeus americanus (Brachyura,Panopeidae) in a remnant mangrove area in the southwest Atlantic

The distribution and density of a population of the narrowback mud crab Panopeus americanus were evaluated, with emphasis on the different developmental stages (juveniles and adults) and sexes. Specimens were collected in a remnant human‐impacted mangrove at Araçá on the northern coast of São Paulo, Brazil, at two‐month intervals from January through July 2006, using 1 m×1 m sample plots randomly distributed in the intertidal zone. The population was abundant, with a mean density of 14.3±9.3 individuals/m². Larger individuals were more abundant in the upper and middle intertidal zones, whereas smaller crabs were predominant in the lower intertidal and thus remained submerged longer. Males and juveniles were homogeneously distributed. Females preferred regions farther from the waterline. A clustered distribution pattern suggested gregarious behaviour and settling of juveniles in the vicinity of the adults' habitats, in an adaptive process as a function of tidal rhythms.     

Two new species of miniature psammophilic sarcoglanidine catfishes of the genus Microcambeva from the Atlantic Forest of eastern Brazil (Siluriformes: Trichomycteridae)

ABSTRACT

Trichomycterid catfishes of the Sarcoglanidinae, which includes small-sized species living in sandy river substratum, have been poorly represented in collections. We herein describe two new species of the sarcoglanidine genus Microcambeva, endemic to river basins draining the Brazilian Atlantic Forest. The presence of a distal widening on the posterior process of the autopalatine and a rudimentary anterior autopalatine ossification shared by the two new species, M. mucuriensis sp. nov. from the Rio Mucuri and M. jucuensis sp. nov. from the Rio Jucu basin, and M. draco from the Rio Jucuruçu basin indicates that these three species are more closely related to each other than to other congeners. Microcambeva mucuriensis seems to be more closely related to M. draco than to M. jucuensis in that the first two species share the presence of a well-developed anterior process of the interopercle. The two new species are also distinguished from congeners by the number of opercular odontodes and premaxillary teeth, and the relative size of the sesamoid supraorbital. Available evidence taken from this study and previous reports indicates that different sarcoglanidine lineages have adapted to live in distinct riverine habitats, with species of Atlantic Forest Microcambeva inhabiting clearwater streams and Amazonian sarcoglanidines found in tea-stained acidic-water streams.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:8CFF9C88-1CEC-44AF-AD26-1D4A56F3D946     

A taxonomic and zoogeographical census of the extant ant taxa (Hymenoptera: Formicidae)

The numbers of extant ant taxa in the world are analysed taxonomically and zoogeographically. A table detailing numbers of subfamilies, tribes and genera, and the numbers of species they contain, and one analysing the number of species per genus per zoogeographical region, are presented. Subfamilies are analysed by number and percentage of genera and species; the most speciose genera are isolated and listed in terms of absolute size and speciosity per subfamily. Tables detailing total numbers of genera and species per subfamily per region, and endemic genera per subfamily per region are given, and the endemicity and speciosity of genera are tabulated on a regional basis.     

Action of the saproxylic scarab larva Cetonia aurataeformis (Coleoptera: Scarabaeoidea: Cetoniidae) on woody substrates

The saproxylic beetle Cetonia aurataeformis Curti (Scarabaeoidea: Cetoniidae) is a common Iberian species, whose larvae develop in tree cavities feeding on wood and litter. The aim of this paper is to analyse how the larvae of this cetonid modify the woody substrate by feeding and what the ecological implications on their microhabitat could be. Thermal analysis and infrared spectroscopy have been used to study the changes suffered by different substrates, litter and wood of Betula alba and Quercus pyrenaica, after digestion by the larvae. Results show that larvae of C. aurataeformis are able to digest polysaccharides and lignin producing a residue richer in nutrients than the original substrate and with an organic structure that contains a fraction of lignin that is easier to decompose. The main conclusion is that the action of cetonid larvae on woody substrates could facilitate their use by other saproxylic organisms in natural ecosystems.     

Carton nest building and trophobiont manipulation in the south-east Asian ant Dolichoderus sulcaticeps (Mayr 1870) (Hymenoptera: Formicidae)

Dolichoderus sulcaticeps, a rare canopy living dolichoderine ant, was studied in the rainforest of Malaysia. It forms large polycalyc colonies comprising partial nests on trees and climbers. The three dimensional multichambered partial nests are situated on the leaf underside. Fibrous nest material is gathered from the surface of the nesting plants and soaked with water from the plant surface. Building activity, therefore, is strictly dependent on the presence of rainfall or dew. Within the cell with plant leaf surface contact, as well as on free feeding sites, non specific coccid and membracid throphobionts, are tended. Free feeding sites are permanently protected. Mealybugs are transported between existing and new free feeding sites, as well as to and from nest pavilions, especially during their construction or destruction. Prey hunting has not been observed in D. sulcaticeps. The workers, however, recruit to offered dead prey, and scavenged. During the day they were permanently on the surface of plants around their nests and feeding sites.     

Maintenance of colour polymorphism in the leaf beetle Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae: Paropsini)

Intra-specific colour differences in insects may occur as a result of environmental factors such as food type, temperature and humidity, or may be under genetic control. These colour polymorphisms may result in fitness differences through several mechanisms, including mate selection, camouflage from or warning to natural enemies, and heat absorption. Two colour morphs of adult Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae: Paropsini) are present in the field in mainland Australia and Tasmania: a common green-brown form, and a rare black form. Tasmanian populations were sampled to assess the frequency of each morph at eight localities. The black form represented less than 3% of beetles (N=1724), with the proportion not significantly different between localities. Crossing tests using the two colour morphs of C. agricola showed that the black form was genetically dominant over the common form. To assess whether colour morphs had any fitness differences, we measured pre-oviposition period, fecundity, longevity, adult size and egg hatch rate, which each showed no significant difference between colour morphs. Field sampling of mating pairs and rearing the offspring of field-collected females showed no evidence of non-random mating. Modelling the population over 100 generations confirmed that for this species, melanism is controlled by a dominant but neutral allele, and, thus, is maintained at a constant low level in the population.