A taxonomic review of the nivicolous species of myxomycetes described by Kowalski. I. Order Stemonitales

Five type specimens of species from the order Stemonitales proposed by Kowalski are re-examined. These are Comatricha fusiforme, Diacheopsis effusa, D. serpula, Lamproderma acanthosporum and L. disseminatum. SEM and LM micrographs of spores, capillitia and sporocarps are provided. Critical study of these type specimens supports Kowalski’s recognition of these taxa as good and valid species.     

The role of Rhytidoponera metallica (Hymenoptera,Formicidae) in facilitating post‐fire seed germination of three ant‐dispersed legume species

The fire avoidance hypothesis proposes that a benefit of seed dispersal by ants (myrmecochory) is to protect seeds from being killed during fire and to facilitate post‐fire germination of seeds that require heat shock to break their physical dormancy. The aim of this study was to quantify the effect of fire and seed burial by a predominant seed‐dispersing ant, Rhytidoponera metallica (subfamily: Ectatomminae) on germination levels of three ant‐dispersed legume species (Pultenaea daphnoides, Acacia myrtifolia and Acacia pycnantha). Experimental burial of seeds within aluminium cans at a site prior to being burnt and at an adjacent unburnt site showed that fire increased germination levels, particularly for seeds buried at 1‐ and 2‐cm deep and that overall, germination levels differed among the three plant species. To quantify seed burial depths and post‐fire germination levels facilitated by R. metallica ants, seeds were fed to colonies prior to fire at the burnt and unburnt sites. Of the seeds buried within nests that were recovered, between 45% and 75% occurred within the upper 6 cm of the soil profile, although unexpectedly, greater percentages of seeds were recovered from the upper 0–2 cm of nests in the unburnt site compared with nests in the burnt site. Germination levels of buried seeds associated with R. metallica nests ranged from 21.2% to 29.5% in the burnt site compared with 3.1–14.8% in the unburnt site. While increased seed germination levels were associated with R. metallica nests following fire, most seeds were buried at depths below those where optimal temperatures for breaking seed dormancy occurred during the fire. We suggest that R. metallica ants may provide fire avoidance benefits to myrmecochorous seeds by burying them at a range of depths within a potential germination zone defined by intra‐ and inter‐fire variation in levels of soil heating.     

Local population persistence as a pre-condition for large-scale dispersal of Idotea metallica(Crustacea, Isopoda) on drifting habitat patches

Idotea metallica establishes self-sustaining populations exclusively on objects drifting at the sea surface. Large-scale transport of drift material with surface currents results in an efficient dispersal of the species. Two types of drifting objects are utilised (biotic and abiotic), providing quite different conditions of life. Ephemeral biotic substrata (mainly uprooted macroalgae) may be used for transport and food, however, resulting habitat destruction from feeding must be a major threat for local population persistence of I. metallica. Abiotic substrata or wood represent efficient vectors for long-distance dispersal due to their resistance to biodegradation, but do not provide food for this herbivorous species. In laboratory experiments, the spatially-limited conditions of drifting substrata were simulated in microcosms. Idotea metallica established persistent populations on both types of substrata. On abiotic substrata, however, where the animals were fed only on Artemia larvae, high variations in density and a reduced intrinsic rate of population growth increased the risk of population extinction. Idotea metallica avoids habitat destruction by limited feeding on macroalgae. In contrast, the coastally distributed congener Idotea baltica destroyed algal habitats by feeding about 10 times faster than I. metallica.     

Intraguild predation, cannibalism, and microhabitat use in Calopteryx virgo and Somatochlora metallica larvae: a laboratory experiment

Intraguild predation (IGP) and cannibalism among co-occurring lotic odonate species was studied in Central Finland. A laboratory experiment was performed to assess the microhabitat use and cannibalism between intermediate and late instars of Calopteryx virgo larvae and predation by larger Somatochlora metallica larvae on the intermediate C. virgo instars. The experiment was run in small running-water aquaria where the larvae were able to divide their mutual habitat vertically by clinging onto artificial perches or crawling on the bottom. Life span of the small C. virgo larvae and attack rate on them were compared between the cannibalism and IGP treatments. The effect of predation on the activity, habitat use and spatial distribution of the small C. virgo larvae was examined. The IGP rate was 36%. The prey larvae spent the most of their time on the perches, whereas the S. metallica preferred the substrate. The large C.␣virgo larvae did not cannibalise smaller conspecifics. The presence of a predator (S. metallica) had no effect on the habitat use or activity of the prey (C. virgo) larvae. Habitat use differed more between those species than between conspecifics of different size classes of C. virgo. The spatial distribution between S.␣metallica and C. virgo showed a completely random pattern, whereas the two size classes of C. virgo aggregated in the vegetation. Absence of cannibalism and behavioural observations indicate that C. virgo may have a low tendency for intraspecific aggressions.     

Low relatedness among cooperatively breeding workers of the greenhead ant Rhytidoponera metallica

The greenhead ant Rhytidoponera metallica has long been recognized as posing a potential challenge to kin selection theory, because it has large queenless colonies where apparently many of the morphological workers are mated and reproducing. However, this species has never been studied genetically and important elements of its breeding system and kin structure remain uncertain. We used microsatellite markers to measure the relatedness among nestmates, unravel the fine‐scale population genetic structure, and infer the breeding system of R. metallica. The genetic relatedness among worker nestmates is very low but significantly greater than zero (r=0.082 ± 0.015), which demonstrates that nests contain many distantly related breeders. The inbreeding coefficient is very close to and not significantly different from zero, indicating random mating and lack of microgeographic genetic differentiation. On average, closely located nests are not more similar genetically than distant nests, which is surprising, as new colonies form by budding and female dispersal is restricted. Lack of inbreeding and absence of population viscosity indicates high gene flow mediated by males. Overall, the genetic pattern detected in R. metallica suggests that a high number of moderately related workers mate with unrelated males from distant nests. This breeding system results in the lowest relatedness among nestmates reported for social insect species where breeders and helpers are not morphologically differentiated.     

Negative Effects of Conspecific Floral Density on Fruit Set of Two Neotropical Understory Plants

Plant reproductive success is usually positively related to conspecific floral density, but neutral or negative effects of floral density on reproduction have also been reported. Differences in the relationship between reproduction and floral density largely originate from a trade‐off between increasing attractiveness versus increasing competition for pollinators at high floral densities. Although floral densities strongly vary in the understory of tropical forests, for instance, due to variation in light availability, little is known about the density dependence of reproduction in tropical understory plants. We used path analyses to disentangle direct and indirect effects of canopy openness and floral density on fruit set and analyzed the relationship between pollen load and floral density for two Neotropical understory plants, Heliconia metallica and Besleria melancholica. In both species, fruit set was not directly related to canopy openness, but decreased with increasing floral density. In H. metallica, canopy openness had an indirect negative effect on reproduction mediated by its effects on floral density. Effects of floral density on pollen loads were species‐specific. In B. melancholica, pollen loads linearly decreased with increasing floral density, indicating competition for pollinators at high densities. In H. metallica, pollen loads were reduced at both low and high densities, indicating an interplay of facilitative and competitive effects of floral density on pollen deposition. In contrast to other studies, we found negative density dependence of reproduction in both understory species. Negative effects of floral density on reproduction appear to be related to pollinator‐mediated effects on reproduction rather than to variation in abiotic conditions.     

Metapopulation structure of the marine isopod <Emphasis Type="Italic">Idotea metallica</Emphasis>, a species associated with drifting habitat patches

The neustonic isopod Idotea metallica inhabits objects drifting at the sea surface. Animals found on floating patches represent not just ephemeral assemblages but persistent local populations. Drift material collected in the Mediterranean, the North Atlantic, and the North Sea harboured populations of up to about 50 animals including all developmental stages. In laboratory experiments the species proved to be able to establish populations on spatially limited, isolated substrates. The capacity of 5-litre-microcosms for I. metallica was about 130 animals. In the presence of the coastally distributed congener Idotea baltica, however, laboratory populations of I. metallica went extinct within 12 weeks. Even though high colonisation rates can be expected in coastal waters because of high patch densities, metapopulation persistence is mostly restricted to the open sea. In coastal waters extinction rate of local populations increases because of patch destruction and the species' inferiority to coastally distributed competitors. Due to high uncertainties in estimating patch densities, it is difficult to determine the parameters underlying metapopulation dynamics such as the migration rate and the rate of patch occupancy. Electronic Publication     

New species of <Emphasis Type="Italic">Dypsis</Emphasis> and <Emphasis Type="Italic">Ravenea</Emphasis> (Arecaceae) from Madagascar

Fourteen new species of palms (Arecaceae) from Madagascar are described and named, based on material collected over the last 15 years. Twelve species belong to the genus Dypsis, namely D. andilamenensis Rakotoarin. & J. Dransf., D. anjae Rakotoarin. & J. Dransf., D. betsimisarakae Rakotoarin. & J. Dransf., D. culminis Rakotoarin. & J. Dransf., D. dracaenoides Rakotoarin. & J. Dransf., D. gautieri Rakotoarin. & J. Dransf., D. gronophyllum Rakotoarin. & J. Dransf., D. jeremiei Rakotoarin. & J. Dransf., D. metallica Rakotoarin. & J. Dransf., D. reflexa Rakotoarin. & J. Dransf., D. sancta Rakotoarin. & J. Dransf. and D. vonitrandambo Rakotoarin. & J. Dransf. and two species belong to the genus Ravenea: R. beentjei Rakotoarin. & J. Dransf. and R. hypoleuca Rakotoarin. & J. Dransf. Despite the fact that most of these species have been recorded from protected areas that are difficult to access in the eastern region of Madagasacar, they are all threatened. Based on IUCN categories and criteria, seven are Critically Endangered and seven are Vulnerable.     

The recent arrival of the oceanic isopodIdotea metallica Bosc off Helgoland (German Bight, North Sea): an indication of a warming trend in the North Sea?

In 1988 a long-term study was started of the isopod fauna associated with surface drift material off Helgoland (German Bight, North Sea). In the summer of 1994 specimens ofIdotea metallica Bosc were recorded for the first time. There is no evidence that this species has ever been present in the German Bight before. The samples contained males, both gravid and non-gravid females, and juveniles, indicating that the species reproduced successfully in the Helgoland region. Interbreeding of specimens from Helgoland and the western Mediterranean produced fertile off-spring. As a neustonic species,I. metallica shows a high natural capacity for dispersal. It thus seems unlikely that the arrival of the species in the North Sea resulted from an accidental introduction by man. We are probably witnessing an extension of the species’ geographical range by natural means of dispersal, as a response to recent changes in the ecological conditions of the German Bight. Temperature data measured by the Biologische Anstalt Helgoland since 1962 show that the last decade (except 1996) was characterized by unusually mild winters. Following the severe winter of 1996,I. metallica was again absent from the Helgoland region. After the subsequent mild winters (1997 and 1998), however, the species reappeared in the summer of 1998 with higher numbers than ever before. This suggests that the observed phenomena are closely connected with the recent temperature anomalies.I. metallica can be regarded as a potential immigrant to a warmer North Sea, and may be useful as a sensitive indicator of the predicted long-term warming trend.     

Revision of the genera Nemotha Wood-Mason, 1884 and Tricondylomimus Chopard, 1930 stat. rev., with description of a new species (Dictyoptera: Mantodea)

The oriental species previously included in the rarely collected genus Nemotha Wood-Mason, 1884 (Mantodea: Iridopterygidae) are revised. N. coomani (Chopard, 1930) and N. mirabilis Beier, 1933 strongly differ from the type species N. metallica (Westwood, 1845) by family-level morphological features, but share a unique type of forefemoral armament with the genera Hapalopeza Stål, 1877 and Amantis Giglio-Tos, 1915, suggesting Nemotha is of a polyphyletic nature. The genus Tricondylomimus Chopard, 1930 is resurrected from synonymy to accommodate T. coomani, T. mirabilis n. comb. and the species which is newly described in this article, T. intermedius n. sp. The monotypic genus Pseudogousa Tinkham, 1937 and its species P. sinensis Tinkham, 1937 are synonymized with Tricondylomimus and T. mirabilis, respectively. The genus Tricondylomimus is placed in Iridopterygidae, while Nemotha is transferred to Hymenopodidae: Anaxarchini.     

Torus-shaped bands in polytene chromosomes of Drosophila. Relationship of toroidal structures and intercalary heterochromatin

Certain regions of the salivary gland polytene chromosomes of Drosophila auraria and its closely related species D. triauraria and D. quadraria, exhibit definite toroidal structures, as evidenced in routinely fixed and stained squash preparations under the light microscope. These toroids are associated with intercalary heterochromatin, as revealed by ectopic pairing and weak points. Similar observations on the giant chromosomes of D. melanogaster are discussed.     

Marine Isopoda of The Snares islands,New Zealand — 1. Gnathiidea,Valvifera, Anthuridea,and Flabellifera

Abstract

Twenty-four species of shallow-water marine non-asellote isopods are described or noted from collections made by University of Canterbury workers at The Snares islands (asterisks denote new records): Gnathia akaroensis* (Gnathiidae); Neastacilla antipadea n.sp., N. tuberculata* (Arcturidae); Crabyzos elongatus*, Euidotea peronii*, Idotea metallica* (ldoteidae); Mesanthura sp. (Anthuridae); Colanthura rima n.sp., Paranthura flagellata* (Paranthuridae); Cirolana rossi*, Cirolana sp. (Cirolanidae); Lironeca raynaudii* (Cymothoidae); Limnoria quadripunctata* (Limnoriidae); Plakarthrium typicum* (Plakarthriidae); Amphoroidea falcifer, A. longipes*, Dynamenella condita, D. huttoni, Scutuloidea maculata, Ciliacaea caniculata, Cymodoce allegra, Exosphaeroma obtusum, Isocladus calcareus, and Pseudosphaeroma campbellensis (Sphaeromatidae). Cymodoce australis has been recorded from The Snares but was not represented in the material examined. The genus Paradynamenopsis from Chile is made a junior synonym of Pseudosphaeroma.     

Amphipods, isopods and surface currents: a case for passive dispersal in the Bay of Fundy, Canada

Six species of isopods and 18 species of amphipods were collectedin the neuston of the Bay of Fundy and adjacent waters. Collectionswere made over a grid of stations covering 2.4x10⁴ km² duringthree spring, three summer and two autumn surveys. No isopodsand only five species of amphipods were found in spring surveys.Isopods and amphipods were diverse and plentiful in the neustonin summer and autumn. Dominant isopods were Idotea baltica andI.metallica, and dominant amphipods were Calliopius laeviusculusand Parathemisto gaudichaudi. Amphipods and isopods reach theneuston of the Bay of Fundy in three ways. Idotea metallica,the only euneustonic species present, was probably advectedinto the Bay of Fundy from southern waters in summer, and didnot appear to overwinter in the Bay. Most species, includingI.baltica, were collected with drifting littoral vegetation,and we suggest that transport by surface currents is an importantfactor in dispersal of some shoreline crustaceans. Midwaterplankton, such as Parathemisto gaudichaudi, reached the neustoneither by advection in upwelling waters or by an extension oftheir normal diel vertical distribution.     

A molecular phylogeny of the north‐east Atlantic species of the genus Idotea (Isopoda) with focus on the Baltic Sea

Today, the marine isopods of the genus Idotea Fabricius, 1798 consist of 26 accepted species. Most species can be found in the Northern Hemisphere. While some species have a cosmopolitan distribution, others are endemic to a few coastlines. In the Baltic Sea, Idotea species have a key role as important meso‐grazers. Only three species can be found in this brackish environment, I. balthica, I. chelipes and I. granulosa, while nine species are described from the whole European coast. The goal of the present study was to reconstruct the phylogeny of the genus Idotea and to test whether the Baltic low‐salinity tolerant species represent a single lineage within the genus. The phylogeny of north‐east Atlantic Idotea species was investigated based on a fragment of the nuclear gene 28S and the mitochondrial gene COI for eight Idotea species. The phylogenetic reconstructions showed that the genus Idotea might not be monophyletic. Neither I. linearis nor I. urotoma did belong to the separated and well‐supported Idotea clade of I. balthica, I. chelipes, I. emarginata, I. granulosa, I. metallica and I. pelagica. The three Idotea species found in the Baltic belonged to different lineages, with estimated COI‐based divergence time older than 7 Myr. This suggests that the tolerance to low salinity has likely evolved in the genus Idotea more than once.     

Interspecific interactions between feral pigs and native birds reveal both positive and negative effects

In tropical Australian rainforests, predators and scavengers aggregate beneath emergent trees that house large colonies of metallic starlings (Aplonis metallica), feeding in the nutrient‐rich open areas below. Analysis of camera‐trap records shows that the presence of feral pigs (Sus scrofa) is associated with an absence of birds (cockatoos and brush turkeys), presumably reflecting behavioural avoidance (pigs pose a direct danger to birds). However, bird numbers increase as soon as pigs depart, then fall if pigs are absent for long periods. Feral pigs thus displace native birds from these resource hotspots; but by turning over the soil and enhancing the birds' access to food, the pigs also have a positive impact on food availability for the avifauna. Thus, although invasive species have caused irreparable environmental damages worldwide, they may also provide positive benefits for certain species. The net benefit of such interspecific interactions will depend on the outcome of both positive and negative effects.     

New synonymies for <Emphasis Type="Italic">Ruellia</Emphasis> (Acanthaceae) of Costa Rica and notes on other neotropical species

As part of our study of the Acanthaceae of Costa Rica and from a phylogenetic study of Ruellia as a whole, we place R. barbillana and R. metallica in synonymy with R. terminalis. We discuss species limits of R. terminalis and provide a key that distinguishes it from close relatives including R. grantii, R. oaxacana, and R. phyllocalyx. Ruellia puri is put into synonymy with R. jussieuoides, and R. standleyi is synonymized with R. ochroleuca. Disjunct distributions characterize R. terminalis, R. jussieuoides, and R. ochroleuca, although this pattern is most extreme in R. ochroleuca. Phylogenetic analysis of DNA sequence data lends support to our synonymy decisions. New lectotypifications are provided for Arrhostoxylum achimeniflorum, Dipteracanthus puri, Dipteracanthus puri β angustifolius, Dipteracanthus puri γ gymnocladus, Lychniothyrsus ochroleucus, and Otacanthus pearcei .     

Foraging decisions of individual workers vary with colony size in the greenhead ant Rhytidoponera metallica (Formicidae, Ectatomminae)

Summary. The ability of worker ants to adapt their behaviour depending on the social environment of the colony is imperative for colony growth and survival. In this study we use the greenhead ant Rhytidoponera metallica to test for a relationship between colony size and foraging behaviour. We controlled for possible confounding ontogenetic and age effects by splitting large colonies into small and large colony fragments. Large and small colonies differed in worker number but not worker relatedness or worker/brood ratios. Differences in foraging activity were tested in the context of single foraging cycles with and without the opportunity to retrieve food. We found that workers from large colonies foraged for longer distances and spent more time outside the nest than foragers from small colonies. However, foragers from large and small colonies retrieved the first prey item they contacted, irrespective of prey size. Our results show that in R. metallica, foraging decisions made outside the nest by individual workers are related to the size of their colony.Received 23 March 2004; revised 3 June 2004; accepted 4 June 2004.     

Multiphase myrmecochory: the roles of different ant species and effects of fire

Seed dispersal by ants (myrmecochory) can be influenced by changes to ant assemblages resulting from habitat disturbance as well as by differences in disperser behaviour. We investigated the effect of habitat disturbance by fire on the dispersal of seeds of a myrmecochorous shrub, Pultenaea daphnoides. We also investigated the consequence of the seed relocation behaviours of two common dispersers (Pheidole sp. A and Rhytidoponera metallica) for the redispersal of seeds. Pheidole sp. A colonies did not relocate seeds outside their nests. In contrast, R. metallica colonies relocated 43.6 % of seeds fed to them, of which 96.9 % had residual elaiosome that remained attached. On average, R. metallica relocated seeds 78.9 and 60.7 cm from the nest entrances in burned and unburned habitat, respectively. Seeds were removed faster in burned than in unburned habitat, and seeds previously relocated by R. metallica were removed at similar rates to seeds with intact elaiosomes, but faster than seeds with detached elaiosomes. Dispersal distances were not significantly different between burned (51.3 cm) and unburned (70.9 cm) habitat or between seeds with different elaiosome conditions. Differences between habitat types in the frequency of seed removal, the shape of the seed dispersal curve, and the relative contribution of R. metallica and Pheidole sp. A to seed dispersal were largely due to the effect of recent fire on the abundance of Pheidole sp. A. Across habitat types, the number of seeds removed from depots and during dispersal trials most strongly related to the combined abundances of R. metallica and Pheidole. Our findings show that myrmecochory can involve more than one dispersal phase and that fire indirectly influences myrmecochory by altering the abundances of seed-dispersing ants.     

Further observations on the genus Didymosphaenia M. Schmidt—D. Sibirica (Grun.) M. Schm.

Maintenance of Didymosphaenia M. Schmidt as a distinct diatom genus is supported by an examination of D. sibirica (Grun.) M. Schm. with the scanning electron microscope. This investigation of D. sibirica reveals features similar to those of D. geminata (Lyngb.) M. Schm. and substantiates the existence of the genus separate from Gomphonema. D. sibirica is, however, a quite distinct species.     

<Emphasis Type="Italic">Metarhizium taii var. chongqingensis</Emphasis> Nov., Anamorph of <Emphasis Type="Italic">Cordyceps</Emphasis><Emphasis Type="Italic">chongqingensis</Emphasis> sp. Nov. Isolated from a Low Altitude Area in Chongqing,China

Previously, a new Cordyceps species was isolated from a low altitude area in Chongqing, China, and named Cordyceps chongqingensis sp. nov. In this study, its anamorph was isolated and designated CQM1^T. It grew optimally on Czapek medium supplied with 0.5% silkworm flour and 0.5% soybean oil meal at 25°C, pH 5.0–5.5. The phenotypic and molecular characteristics were investigated for its identification and typing. Morphological observations under a microscope revealed that this anamorph of Cordyceps chongqingensis sp. nov. was a new species of Metarhizium. Moreover, it was identified as one of the variants of Metarhizium taii based on sequences of 26S rDNA D1/D2 and ITS regions, and thus named Metarhizium taii var. chongqingensis nov.