On the status of Arcitalitrus dorrieni (Crustacea: Amphipoda) on the island of Colonsay,Inner Hebrides

The presence of the landhopper Arcitalitrus dorrieni (Hunt) is reported on the island of Colonsay, Inner Hebrides. It is widely distributed there amongst deciduous leaf litter in forested areas but also occurs in bracken litter and scrub grassland. The species is an introduction from Australia, doubtless transported inadvertently among plants brought to the gardens at Colonsay House. It is, however, not restricted to the ornamental plantings but has colonized native woodland. Maximum population density recorded under leaf litter was 680 m². Amphipods avoid waterlogged or dry situations preferring to burrow in moist soil under litter from deciduous trees. Coniferous woodlands are more sparsely colonized. Rate of spread (minimum) from the original locus is calculated at c. 25 m/year. Arcitalitrus may prefer to eat sycamore leaves (cf. oak, beech). Ovigerous females are reported for May but no evidence exists for a release of young any earlier in the year. Immature amphipods seem to live more covert lives in the soil beneath the superficial litter layer. Eggs are relatively large and few in number. Amphipods may avoid ants but may have a mite living in phoretic or ectoparasitic association.     

Natural history of the terrestrial amphipod Cerrorchestia hyloraina Lindeman (Crustacea: Amphipoda; Talitridae) in a Costa Rican cloud forest

The field biology of the Costa Rican landhopper (Crustacea: Amphipoda: Talitridae) Cerrorchestia hyloraina Lindeman was investigated in the Monteverde Cloud Forest Reserve, Costa Rica. On the Pacific (leeward) side of the continental divide, local distribution follows a gradient of moisture, from densities of over 200 m^-2 in the elfin forest at 1600 m, to extremely low densities in drier forest types. Below 1400 m, the leaf litter is apparently too dry to support landhopper populations. On the Caribbean (windward) side of the continental divide, landhoppers occur well below 1400 m. A discussion of geographic distribution is included. Landhoppers prefer aged (microfaunally pre-processed) leaves as food, and move about only at night or in the mornings of heavily overcast days. Average female fecundity is seven eggs, with progressive loss of marsupium contents over time. The sex ratio is biased towards females. In cloud forest, breeding apparently is continuous throughout the year, with some increase after the beginning of the rainy season. There are 9–10 juvenile instars and 5–6 adult instars. The relationship of antennal segment number to total body length is linear.     

Intense inhabitation and relaxed host-leaf preference of aquatic chironomid leaf-miners in headwater streams in Asian lucidophyllous forests

Submerged leaf litter in headwater streams covered by Asian lucidophyllous (glossy broad-leaved evergreen) forests was found to be frequently processed by leaf-mining larvae of a chironomid, Stenochironomus okialbus. The larva gnaws plant tissue of the mine wall while swimming and undulating its body in the water-filled mine. To detect the level of the inhabitation and host-preference of the aquatic leaf-miner, extensive samplings of mined leaves were made in various headwater streams covered by lucidophyllous forests in the Japanese Island Arc. The chironomid showed significant preference for leaf texture (evergreen to deciduous leaves) and for specific taxonomic groups of the host plants (Fagaceae and Lauraceae), whereas diverse taxa of leaves were utilised. The relaxed host-leaf preference unique among herbivorous insects is suggested to be caused by the larval water-circulating behaviour in their porous mines and by leaching and microbial decomposition of plants’ secondary metabolites in submerged leaves.     

Environmental humidity and leaf-litter depth affecting ecological parameters of a leaf-litter frog community in an Atlantic Rainforest area

We studied a leaf-litter frog community from an Atlantic Rainforest area in the state of Espírito Santo, south-eastern Brazil. Frogs were sampled using 4 × 4-m plots. We recorded 348 individuals from 13 species. The estimated overall density of leaf-litter frogs in the study area was 6.6 frogs/100 m² with an estimated overall frog biomass of 0.04 g/ha. Brachycephalus didactylus was the species with the highest estimated density and highest abundance. Five of the litter frog species recorded are considered endemic to the Atlantic Forest and two species are endemic to the state of Espírito Santo, including Euparkerella robusta, which is considered threatened as the result of habitat loss. The overall abundance of leaf litter was positively related to relative humidity and depth of the leaf litter. The relationship between frog body mass and frog abundance was significant, suggesting that a general biological trend in this relationship occurs in our study area.     

Tadpole deposition behaviour in male stream frogs Mannophryne trinitatis (Anura: Dendrobatidae)

Male Mannophryne trinitatis transport their larvae on their backs to predator‐free pools and deposit them there. The experiments reported here investigated M. trinitatis male deposition behaviour in containers placed near a heavily fish‐populated stream at Mount Saint Benedict, northern Trinidad. Choice of deposition site was not related to height above or distance from the stream. The low mean number of tadpoles deposited in each container in the field and in a laboratory experiment indicated that most males tended not to deposit complete clutches in single pools. Deposition experiments in the laboratory with a choice of different‐sized containers showed that deposition was pool size dependent, with more tadpoles deposited in larger containers. Deposition behaviour when given a choice of containers with leaf litter (a source of food and shelter) and with no leaf litter showed no significant preference. Tadpoles grown in different water volumes with different food sources revealed that tadpole growth was best in larger water volumes containing leaf litter. Regular tadpole inspections at a pool in the field established that most tadpoles present were the result of downstream movement.     

Some new and known species of Tylencholaimoidea (Nematoda: Dorylaimida) from Korea

A lineal “island” theory is proposed to account for the dispersal of marine/estuarine, supralittoral talitrid populations, both to and from isolated shore “islands” on continental and true oceanic islands. Evolution may occur following dispersal to shores that are contiguous with ecologically open habitats, inclusive of sub-tropical forest litter and caves. Specific hypotheses of the lineal “island” theory are therefore: the conventional wrack hypothesis 1 – direct from marine supralittoral wrack to subtropical forest litter; the driftwood hypothesis 2(a) – direct from marine supralittoral driftwood to subtropical forest litter; the driftwood hypothesis 2(b) – direct from the marine supralittoral driftwood to caves opening on a marine supralittoral; and the driftwood hypothesis 2(c) – direct from the marine supralittoral driftwood via caves to subtropical forest litter. Circumstantial evidence supporting each hypothesis is presented using the ecology and distribution data of the talitrid fauna of the northeast Atlantic islands, north of 25°N and south of 40°N, including the Canaries, Madeira and the Azores archipelagos. The currently known talitrid fauna of all these islands includes 15 species: seven endemic, subtropical landhoppers, two synanthropically introduced landhoppers, three wrack generalists, one sand-burrowing specialist, one specialist cavehopper, and one specialist driftwood hopper. Based on distributional data from the northeastern Atantic islands, specialist driftwood hoppers have a long distance dispersal capability, which makes them potential colonizers of distant oceanic islands. Talitrids provide an excellent model of dispersal and speciation, whose evolutionary pathways can be solved by modern genetic methods.     

Co-existence of myxomycetes and beetles in an Atlantic Rainforest remnant of Pernambuco,Brazil, with emphasis on staphylinids (Coleoptera: Staphylinidae)

The relationship between myxomycetes and insects was investigated in a fragment of the Brazilian Atlantic Rainforest located in the city of Recife, Pernambuco, north-eastern Brazil. Sixteen excursions into the Dois Irmãos State Ecological Reserve (7°55′43′′ to 8°09′17′′ S, 34°52′05′′ to 35°00′59′′ W, 387.4 ha) were carried out during different seasons between August 2005 and August 2007 for observations and collections of myxomycetes and insects on decomposing trunks and leaf litter. A total of 196 specimens of myxomycetes was obtained, representing 31 species, 16 genera and six families. Baeocera sp. (Coleoptera, Staphylinidae) individuals predominated (86%) in the sample, found on the sporocarps of four species of Trichiales (Arcyria cinerea, Arcyria denudata, Hemitrichia calyculata, Hemitrichia serpula) and two species of Liceales (Lycogala epidendrum, Tubulifera microsperma). No preference was observed for type of sporocarp. No seasonal influence was found for the establishment of these associations, recorded for the first time in this forest environment.     

On the genus Penthesilenula Rossetti and Martens, 1998 (Crustacea,Ostracoda, Darwinulidae) from (semi-) terrestrial habitats in São Paulo State (Brazil), with the description of a new species

Three species of darwinulid ostracods, belonging to the genus Penthesilenula, are reported from terrestrial and semi-terrestrial habitats in São Paulo State (Brazil). Penthesilenula reidae n. sp. is here described as new to science. It belongs to the africana-group in the genus and was found exclusively in bromeliad pouches. Penthesilenula aotearoa (in the incae-group) was previously known from New Zealand only and is here reported for the first time from South America. The third species, Penthesilenula brasiliensis, is here described from leaf litter in forests, constituting the first darwinulid taxon to be found in fully terrestrial habitats. The morphological diversity within P. brasiliensis s. l. is discussed and various lineages on different continents are retained within this species. The evolutionary significance of the high incidence of teratologies in the Darwinulidae is discussed. A tentative homology for the apical chaetotaxy of A2 between Darwinulidae and Cyprididae is offered.     

Foraging mode of Australolacerta rupicola (FitzSimons, 1933) (Sauria: Lacertidae): evidence of seasonal variation in an extremely active predator?

Foraging mode of the endemic Soutpansberg rock lizard (Australolacerta rupicola) was determined by (1) measuring the number of movements per minute (MPM) and the percentage time spent moving (PTM); and (2) analysing faecal samples. Furthermore, these criteria were related to diet composition, proportion of attacks initiated while moving and foraging substrate. The results are discussed in comparison to the foraging modes of 20 other lacertid species. Values for MPM and PTM as well as faecal analysis indicate an active foraging strategy for A. rupicola. Although rock living, this species mostly forages in leaf litter where it is well camouflaged while actively searching for sedentary prey. Even in comparison to other active foragers of the family Lacertidae, A. rupicola displays the prototypic behaviour of a widely foraging lizard with very high PTM and very low MPM.     

A comparison of the structure and function of the cerotegument in two species of Cryptostigmata (Acarina)

Cerotegument plastron structure and function are compared in two species of non-related Cryptostigmata from different families in two environments prone to flooding, namely soil and leaf litter, as represented by Euzetes globulus (Nicolet) (Euzetidae), and the intertidal zone by Ameronothrus marinus (Banks) (Ameronothridae). Differences in cerotegument structure reflect the degree of exposure to mechanical stresses and hydrostatic pressure encountered in these two environments. Cerotegument plastrons communicate with the tracheal system in heavily armoured species, e.g. E. globulus, but gas transfer may occur across the cuticle in those species having a lightly sclerotized leathery cuticle, e.g. A. marinus.     

Habitat use and diet of the endemic lizard Ameivula nigrigula (Squamata: Teiidae) in Caatinga domain,Northeastern Brazil

ABSTRACT

The lizard Ameivula nigrigula is endemic to Caatinga vegetation and the transition zone between the Caatinga and Cerrado domains in Brazil. It was recently described, but little is known about its biology. We analysed microhabitat use and the diet of this species in Caatinga vegetation in Santo Inácio, Bahia State. Its diet consisted mainly of arthropods and plant material, and in particular aggregate (e.g. termites) and large preys (e.g. Coleoptera, insect larvae and spiders), reflecting their nutritional and energy values and high water contents. With regard to habitat use, we found A. nigrigula using microhabitats with tall vegetation over accumulated leaf litter, which could potentially contribute to temperature regulation. Together, those characteristics contribute to the survival of lizards in environments with low water availability and high temperatures, such as the Caatinga domain.     

A comparative study of the gill area relationships in some talitrid amphipods

The total gill area and gill distribution of seven talitrid species taken from a variety of habitats have been studied. In the sandhoppers, Talitrus and Talorchestia, and in the landhopper, Arcitalitrus dorrieni, the greatest gill area is invested in the posterior gills (G6) whereas in the beachflea, Orchestia spp., G2 has the greatest area. Gills 3, 4 and 5 are characteristically small and G7 is consistently absent in all the species studied. Gill structure and deployment patterns are, in general, quite conservative within the Talitridae. The gills of A. dorrieni are, however, complex in shape and are more convoluted than in the other species studied.

Gill area/body dry weight relationships were established for each species and are compared with previously published data. The Talitridae show a reduction in total gill area compared with most aquatic amphipods. It was observed, however, that the slopes of the calculated regression lines were significantly different between the sandhopper and beachflea genera studied. The reduction in gill area within the Talitridae is discussed in relation to their colonization of land.     

Foraging ecology of the giant Amazonian ant Dinoponera gigantea (Hymenoptera,Formicidae, Ponerinae): activity schedule,diet and spatial foraging patterns

This study provides a detailed account of the natural history and foraging biology of the ponerine ant Dinoponera gigantea in a rainforest in north Brazil. The species nests on the ground and the colonies contain 70–96 workers. Ant activity is negatively correlated with temperature, and is more intense at dawn and dusk. Foragers leave the nest independently and search for food individually on the leaf litter, within ca 10 m around the nest. Workers are opportunistic feeders that collect seeds and fruits, and hunt for live prey as well as scavenge for dead animal matter. The dry weight of food items ranges from <10 mg (spiders, insect parts) to >400 mg (seeds, fruits). There is no nestmate recruitment during the search for or retrieval of food, irrespective of food type and size. Foragers have a high directional fidelity, and ants from neighbouring colonies may engage in ritualized territorial contests at the border of their foraging areas. The foraging ecology of D. gigantea is compared with other ponerine species living in tropical forests, as well as with other ant groups showing similar behavioural patterns.     

Ecological aspects of the pumpkin toadlet,Brachycephalus garbeanus Miranda-Ribeiro, 1920 (Anura: Neobatrachia: Brachycephalidae), in a highland forest of southeastern Brazil

Brachycephalus garbeanus is an aposematic toadlet, endemic to the Atlantic Forest in the mountains of the state of Rio de Janeiro, southeastern Brazil. Information regarding the ecology of species in this genus is scarce, with no information on most species, including B. garbeanus. We provide ecological information about B. garbeanus, in particular regarding microhabitat use, sexual dimorphism in body size, and feeding habits. Our study was conducted in a montane area of the Parque Estadual dos Três Picos, the largest State park in Rio de Janeiro. Most of the B. garbeanus in the study area were found on the forest floor leaf litter. Females were larger on average than males. Brachycephalus garbeanus consumed a wide array of prey, comprising exclusively invertebrates and predominantly arthropods. There were seasonal differences in the diet composition, but mites and ants were important in both wet and dry seasons.     

Zoogeography and evolutionary ecology of the genus Platorchestia (Crustacea,Amphipoda, Talitridae)

ABSTRACT

Species of the genus Platorchestia occur both in the northern hemisphere (18 species) and southern hemisphere (three species plus a synanthropically introduced species in South America and South Africa). The greater number of endemic Platorchestia species in the North Pacific Ocean suggests that it could be the epicentre of evolution for this genus. North-western Pacific Platorchestia includes 15 species which occupy five ecotopes: wrack (seven species), terrestrial leaf litter (five species), freshwater (one species), marsh (one species) and tentatively present in caves (one species). North-eastern Pacific Platorchestia includes only one putative driftwood specialist, with no other species found in North American coastal habitats. This compares with three good endemic Platorchestia species (plus two putative additional species) and only two ecotopes: wrack (three species) and freshwater (two species) from the North Atlantic Ocean, inclusive of the Gulf of Mexico and Mediterranean Sea. Insufficient data is available to consider Platorchestia zoogeography for the Arabian Sea and Bay of Bengal. Synanthropic dispersal involving Platorchestia in Polynesian outrigger canoes, or in solid ballast carried in the holds of wooden sailing ships has been identified as a potential complicating factor in the zoogeography of this genus. Platorchestia is proposed to have arisen on Laurasia and is therefore basically a northern hemisphere genus. Questions concerning Platorchestia zoogeography and evolutionary ecology are posed and two methods (more intensive field sampling and molecular genetics) are suggested to be the way to solve them.     

Ecological studies on Aechmea bracteata (Swartz) (Bromeliaceae)

In the Yucatan peninsula, Mexico, Aechmea bracteata is more frequent in the low inundated forest than in hummocks or the semi-evergreen forest. Due to its flat smooth, ovoid seeds disseminated by birds, this epiphyte generally develops on rough-barked trees at the point where a large branch forks out. The presence of a rhizome permits the formation of groups of ramets comprising different levels of development from young shoots to blossoms and the differential rotting of dead dry ramets. In green mature ramets, an amphora-shaped leaf develops around the inflorescence, delimiting a central watertight cavity. Around this central cavity, inter-leaf spaces correspond to peripheral cavities where rainwater may accumulate. This structure permits the plant to be both a phytotelm and a myrmecophytic epiphyte, with green ramets sheltering a large diversity of both aquatic (mostly Diptera larvae) and terrestrial animals (mostly ants, cockroaches, mites, and springtails). Concerning ants, peripheral cavities sheltered small Myrmicinae (31·3% of the ramets), central cavities Pachycondyla villosa (Ponerinae) or Dolichoderus bispinosus (Dolichoderinae) (91·9%; N = 248). Rotting dry ramets sheltered only terrestrial animals, mostly detritivores which are classically present in the leaf litter and ants such as Cyphomyrmex minutus, a primitive Attini and numerous Ponerinae, predators of the detritivores. Both green and dry ramets constituted good shelters for incipient colonies.     

XV.—Information respecting botanical travellers

Summary

A new species of mysid, Parvimysis pisciscibus, is described from leaf litter banks in the Igarapé Tarumazinho, a freshwater side stream of the Rio Negro, Brazil. This small species is the first freshwater mysid to be described from the Amazon basin.     

Two new species of the genus Pseudolaelaps Berlese, 1916 (Acari: Mesostigmata: Pseudolaelapidae) from Europe,with an updated key to known species

Pseudolaelaps calvescens sp. nov. and Pseudolaelaps schweizeri sp. nov. (Acari: Pseudolaelapidae) are described based on female specimens from leaf litter and soil of forest habitats in Italy (surroundings of Bergamo) and Switzerland (surroundings of Basel), respectively. The British specimens referred to Pseudolaelaps doderoi are revised, and considered to be a misidentification of P. schweizeri sp. nov. An identification key to known species of the genus Pseudolaelaps is provided.

www.zoobank.org/urn:lsid:zoobank.org:pub:92F3907A-9C0A-4309-8D1E-BC5F3E7D937B     

Spatial and temporal distributions of juvenile horseshoe crabs (Arthropoda: Chelicerata) approaching extirpation along the northwestern shoreline of the New Territories of Hong Kong SAR,China

Juvenile horseshoe crabs, Tachypleus tridentatus and Carcinoscorpius rotundicauda, with prosomal widths of between 11.5 and 102.5 mm, occur along Hong Kong's northwestern shoreline abutting Deep Bay where dissolved oxygen (DO) has been identified as the principal factor determining distribution and survival. Unreported upon hitherto, however, Tachypleus tridentatus occurred consistently in association with sea-grass (Halophila beccarii) beds, with DO concentrations of 8–14 mg·L^?1, a median grain size of >180 μm, interstitial water contents of <36% (sediment wet weight) and organic contents of <3.2% (sediment dry weight). Most individuals occurred between 60 and 120 m down from the shoreline although there appeared to be a trend of down-shore migration in summer, possibly to alleviate thermal stress. No individuals were found at sediment temperatures ≤20°C, i.e. in sub-tropical Hong Kong's winter, when they adopt buried repose. Abundances of emerged T. tridentatus, peaking in November, were synchronized with interstitial salinities of 22–26‰ and averaged 1–2 individuals per 100 m². Mean population density of T. tridentatus was 4–9 individuals per 100 m². Only four individuals of C. rotundicauda were found in August and September, suggesting a recent dramatic decline in numbers. The natal crèche environment for juvenile horseshoe crabs in Hong Kong is deteriorating and threatening their survival.     

Seasonal cycle of zooplankton abundance and biomass in Hamsilos Bay,Sinop, Southern Black Sea,Turkey

In this investigation, zooplankton was studied between July 2015 and June 2016 in Hamsilos Bay to examine spatial and temporal variations in abundance, biomass and taxonomic composition. The recorded mean zooplankton abundance and biomass were 3770.35 ind. m^?3 and 25.06 mg m^?3 in the inner station, 3928.11 ind. m^?3 and 28.19 mg m^?3 in the middle station and 3948.22 ind. m^?3 and 28.74 mg m^?3 in the outer station, respectively. The high abundance and biomass values observed in September 2015 were attributed to Oithona davisae (4575 ind. m^?3 at the inner station) and Penilia avirostris (33.4 mg m^?3 at the outer station), respectively. Copepoda was the most abundant during the entire period of the survey. In terms of abundance and biomass, Copepoda was followed by meroplankton and Cladocera. Most species within the zooplankton community exhibited evident seasonality throughout the year in Hamsilos Bay. This was particularly apparent for O. davisae, Centropages ponticus, Cladocera and meroplankton, which were abundant in summer–autumn, and for Pseudocalanus elongatus, which was more abundant during winter and spring. It has been determined that O. davisae, which is a non-indigenous cyclopoid copepod species of the Black Sea, has successfully inhabited southern Black Sea and has established a permanent population in this area.