Oogenesis of the mayfly Habrophlebia eldae: Synthesis of vitelline and chorionic envelopes

The ultrastructure of developing ovarian follicles inside the panoistic ovarioles of Habrophlebia eldae were examined to observe the events occurring during egg maturation up to the full formation of the chorionic envelopes. The early vitellogenic follicles are coupled by gap junctions and are extensively interlocked with the oocyte plasma membrane via microvilli. With the onset of vitellogenesis, coated pits and coated vesicles are precursors to yolk deposition and are visible at the follicle cell-oocyte interface. Postvitellogenic development entails the deposition of the egg envelopes. The vitelline envelope arises from the coalescence of rectangular plaques whose precursors are visible in Golgi complexes as heterogeneous electron-opaque granules. A chorionic pattern of ridges on the egg surface characterizes the shell of H. eldae. The fully developed chorion shows three distinct regions with differently organized patterns. A fine layer of fibrous material (a secretion of the follicle cells, Ephemeroptera devoid of accessory glands) adheres to the egg chorion and is probably involved in attachment to the substrate.     

Yoraperla altaica,a New Species of Peltoperlidae (Plecoptera) from East Kazakhstan (Central Asia)

A new species of peltoperlid, Yoraperla altaica sp. n., from East Kazakhstan is described as adult male, adult female, mature nymph and egg stages. The new species is compared with related congeneric species.     

Reproductive biology of caridean decapods from the Weddell Sea

Summary Data on reproductive biology are presented for five benthic caridean shrimps from the high Antarctic (Chorismus antarcticus, Notocrangon antarcticus, Nematocarcinus lanceopes, Lebbeus antarcticus and Eualus kinzeri). The first three species were very common on the Weddell Sea shelf and upper slope, whereas only a few individuals of the other two species were caught-but these did include some ovigerous females. Our measurements include size at first maturity, fecundity (total number and mass of eggs), individual egg mass, egg length, ovary indices, maximum size encountered and documentation of the reproductive cycle in spring and summer. Egg number generally increases with female size, and the largest species (N. lanceopes) also carries the highest number of eggs. The eggs of all high Antarctic species are large, the extreme being L. antarcticus with an egg length of up to 3.3 mm. For C. antarcticus and N. antarcticus, which have wide geographic distributions, a comparison is made with older published and unpublished data from the Subantarctic (South Georgia). High Antarctic representatives of these two species grow to a larger maximum size, attain sexual maturity later in their life cycle, and produce fewer and larger eggs in relation to both carapace length and female mass, than their Subantarctic counterparts.Data presented here were collected during the European Polarstern Study (EPOS) sponsored by the European Science Foundation     

Mating Behavior of Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae): Potential for Outbreeding in a Predominantly Inbreeding Species

The mating behavior of the quasi-gregarious egg parasitoid Trissolcus basalis (Wollaston) was investigated under field conditions. Trissolcus basalis has female-biased sex ratios and is a protandrous species, with males emerging 1–2 days before females. Males competed aggressively for control of the egg mass, with one male assuming dominance and control of the egg mass, although changes in dominance occurred at least once on each egg mass observed. Typical mating behavior involved the dominant male mating his sisters immediately upon their emergence from the egg mass. These behaviors are characteristic of an inbreeding species that manifests local mate competition. However, several aspects of the mating behavior of T. basalis are inconsistent with that of an inbreeding species. Over 18% of emerging females were not mated by the dominant male upon emergence, 13% of females were not observed to be mated at all and may have left their natal site as virgins, 25% of females were mated multiple times and sometimes by multiple males, females remained near the natal site for up to several hours after emergence before emigrating, and males dispersed away from the natal site during female emergence. Trissolcus basalis may be a predominantly inbreeding species but its emergence and mating behavior suggest that low-frequency outbreeding is also likely to occur.     

Species recognition and phylogenetic relationships of European <Emphasis Type="Italic">Porodaedalea</Emphasis> (Basidiomycota,Hymenochaetales)

The genus Porodaedalea is a taxonomically difficult complex of morphologically similar species that inhabit conifers. The evolutionary relationships of European species were examined using sequences of the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA and of translation elongation factor 1 alpha (tefa). Our results confirm the occurrence of Porodaedalea chrysoloma, P. pini and P. laricis in Europe. P. laricis is newly reported in Fennoscandia on Picea and in the Central European mountains (Alps, High Tatras, and Bohemian forest) on Larix and Pinus spp. These specimens had been previously identified as Porodaedalea chrysoloma or Phellinus vorax (an invalidly described species). Although frequently confused, P. chrysoloma and P. laricis can be distinguished on the basis of pore morphology. We also report our finding of P. pini on Larix. In general, the tefa sequences are more variable than the ITS sequences and reveal the remarkable affinity of some Scandinavian and Central European specimens of P. laricis to those from Central Asia. Furthermore, we discovered evidence of interspecific hybridisation between P. pini and P. laricis. In addition, our study revealed the presence of an undescribed species in Morocco. Our results are compared with the results of compatibility tests in this genus that have been published previously.     

Species identity of geographically distinct populations of the glassy-winged sharpshooter parasitoid Gonatocerus ashmeadi: morphology, DNA sequences, and reproductive compatibility

Gonatocerus ashmeadi is a common and seemingly widespread egg parasitoid of Homalodisca coagulata, the glassy-winged sharpshooter (GWSS). Location records for G. ashmeadi indicate its natural range to be the southeastern USA and northeastern Mexico (which coincides with the presumed native range of GWSS), and possibly southern and central California (CA) (the adventive range of GWSS). The purpose of our work was to determine whether G. ashmeadi in the USA and northeastern Mexico is one species or a complex of reproductively incompatible sibling species. We used three approaches to determine the species identity of different G. ashmeadi populations: (1) reassessment of key morphological features using scanning electron microscopy (SEM) to determine if subtle morphological differences exist between G. ashmeadi populations which could indicate species differences; (2) to determine if molecular differences exist between G. ashmeadi populations collected from different regions by comparing mitochondrial and ribosomal DNA sequences; (3) mating compatibility studies to determine if different populations of G. ashmeadi are reproductively isolated, or if mating occurs, whether offspring are viable thereby defining species groups on the basis of successful interbreeding. Results from these three areas (morphology, DNA sequences, and reproductive compatibility) have been evaluated collectively; leading us to the conclusion that G. ashmeadi as it is currently viewed is a valid species and not an aggregate of morphologically indistinguishable cryptic species.     

Species richness, area and climate correlates

Aim Species richness–area theory predicts that more species should be found if one samples a larger area. To avoid biases from comparing species richness in areas of very different sizes, area is often controlled by counting the numbers of co‐occupying species in near‐equal area grid cells. The assumption is that variation in grid cell size accrued from working in a three‐dimensional world is negligible. Here we provide a first test of this idea. We measure the surface area of c. 50 × 50 km and c. 220 × 220 km grid cells across western Europe. We then ask how variation in the area of grid cells affects: (1) the selection of climate variables entering a species richness model; and (2) the accuracy of models in predicting species richness in unsampled grid cells. Location Western Europe. Methods Models are developed for European plant, breeding bird, mammal and herptile species richness using seven climate variables. Generalized additive models are used to relate species richness, climate and area. Results We found that variation in the grid cell area was large (50 × 50 km: 8–3311 km²; 220 × 220: 193–55,100 km²), but this did not affect the selection of variables in the models. Similarly, the predictive accuracy was affected only marginally by exclusion of area within models developed at the c. 50 × 50 km grid cells, although predictive accuracy suffered greater reductions when area was not included as a covariate in models developed for c. 220 × 220 km grid cells. Main conclusions Our results support the assumption that variation in near‐equal area cells may be of second‐order importance for models explaining or predicting species richness in relation to climate, although there is a possibility that drops in accuracy might increase with grid cell size. The results are, however, contingent on this particular data set, grain and extent of the analyses, and more empirical work is required.     

Short-Lived Tree Species and Their Role as Indicators for Plant Diversity in the Restoration of Natural Forests

Anthropogenic forests, particularly conifer monocultures, today constitute a large proportion of Central European woodland. Conversion of such forest stands into abundantly structured mixed‐species woodland is within the focus of ecosystem restoration and is considered to affect forest biodiversity. Short‐lived tree species play an important role in such conversion processes and may serve as focal species. However, not much is known about their relationship with forest biodiversity. In this study, the short‐lived tree species, European mountain ash (Sorbus aucuparia L.), European white birch (Betula pendula Roth), Downy birch (B. pubescens Ehrh.), and Glossy buckthorn (Frangula alnus P. Mill.), commonly occurring throughout Central Europe, are investigated with regard to their relationship with plant diversity. The focus is on their occurrences in Scots pine (Pinus sylvestris L.)–dominated forests in the Northeast German lowlands. A significant increase in vascular plant diversity is revealed in stands with the selected species’ presence, in comparison to stands without them. Increase in plant species numbers is highest where the respective species occurs in the tree and/or shrub layer, compared with their presence only in the herb layer. For bryophyte species, there is a less strong inverse relationship. An analysis of different species groups, such as threatened, woody, and typical forest species of higher plants, reveals no decrease in species numbers in these groups if short‐lived tree species are present. It is concluded that short‐lived tree species can be indicators for plant diversity assessment within forest restoration processes. As to causal explanations, effects of differing site conditions, assessed by use of Ellenberg indicator values, are discussed as well as possible active effects of the tree species changing their environment.     

Selective Acceptance of Alien Host Species Pupae by Slaves of the Dulotic Ant,Harpagoxenus sublaevis (Hymenoptera,Formicidae, Myrmicinae)

The European slave-making ant, Harpagoxenus sublaevis, has up to three host species which occasionally are found all together in one colony. Colonies with only Leptothorax acervorum slaves, or with both L. acervorum and L. muscorum, are frequent, whereas colonies with only L. muscorum slaves are rare, although young H. sublaevis queens found their colonies about equally frequently with either of the two main host species. We demonstrate here, that the two host species exhibit an asymmetric acceptance behavior towards each other's pupae: L. muscorum workers accept L. acervorum pupae, both in non-enslaved colonies and as slaves in H. sublaevis nests, whereas L. acervorum never accepted L. muscorum pupae. Origin and meaning of this behavioral difference are unknown. The findings, however, might be very important with respect to host specificity and host-parasite interactions also in other slave-making ants.     

Description of the Nymphs and Eggs of Acentrella almohades sp. n. from Morocco and Southern Spain (Ephemeroptera: Baetidae)

The nymph and egg of Acentrella almohades sp. n. are described and illustrated on the basis of material collected in southern Spain (in the upper reaches of the Guadalquivir River Basin) and Morocco (Rif Mountains and Atlas Mountains). Features distinguishing the new species from other European species are discussed and keyed.     

Geographic variation in reproductive success of the parasitoid Asobara tabida in larvae of several Drosophila species

Abstract.

• 1 Asobara tabida is a parasitoid of Drosophila larvae in fermenting substrates. Because it is a widespread species, it may encounter different biotic and abiotic circumstances in various parts of its range.
• 2 The species composition of the host population varies over the parasitoid's range: D.obscura-group species (especially D.subobscura) are the main hosts for northwestern and central European parasitoids; D.melanogaster is the main host for southern European parasitoids.
• 3 D.melanogaster larvae can defend themselves against A.tabida by encapsulating the parasitoid egg, and survival in D.melanogaster is always lower than in D.subobscura.
• 4 Parasitoids from southern European populations are much better able to survive in D.melanogaster than their northwestern and central European conspecifics; parasitoids from different populations are equally well able to survive in D.subobscura.
• 5 The lower survival in D.melanogaster may be partly compensated for by the larger size of parasitoids emerging from this host species compared to parasitoids emerging from D.subobscura.
• 6 Within population groups, larger A.tabida females have more eggs in their ovarioles. Additionally, southern European females have more eggs and less fat than northern and western/central European females. The relationship between size and longevity is ambiguous.
• 7 It is concluded that parasitoids from different populations are adapted to region-specific circumstances.

     

Barcodes Reveal 48 New Species of Tetrahymena,Dexiostoma, and Glaucoma: Phylogeny,Ecology, and Biogeography of New and Established Species

Tetrahymena mitochondrial cox1 barcodes and nuclear SSUrRNA sequences are particularly effective at distinguishing among its many cryptic species. In a project to learn more about Tetrahymena natural history, the majority of >1,000 Tetrahymena‐like fresh water isolates were assigned to established Tetrahymena species with the remaining assigned to 37 new species of Tetrahymena, nine new species of Dexiostoma and 12 new species of Glaucoma. Phylogenetically, all but three Tetrahymena species belong to the well‐established “australis” or “borealis” clades; the minority forms a divergent “paravorax” clade. Most Tetrahymena species are micronucleate, but others are exclusively amicronucleate. The self‐splicing intron of the LSUrRNA precursor is absent in Dexiostoma and Glaucoma and was likely acquired subsequent to the “australis/borealis” split; in some instances, its sequence is diagnostic of species. Tetrahymena americanis, T. elliotti, T. gruchyi n. sp., and T. borealis, together accounted for >50% of isolates, consistent with previous findings for established species. The biogeographic range of species found previously in Austria, China, and Pakistan was extended to the Nearctic; some species show evidence of population structure consistent with endemism. Most species were most frequently collected from ponds or lakes, while others, particularly Dexiostoma species, were collected most often from streams or rivers. The results suggest that perhaps hundreds of species remain to be discovered, particularly if collecting is global and includes hosts of parasitic forms.     

Living Apart Together: On the Biology of two Sympatric Leuctra Species (Plecoptera,Leuctridae) in an Apenninic Stream,Italy

Leuctridae is the richest stonefly family on the European continent, with many species of Leuctra often coexisting in sympatry in the same lotic environment. In this work we studied the life cycle and feeding habits of two species, Leuctra fusca and L. hippopus, coexisting in a small Italian Apennine stream. The life cycles of the two species are non‐overlapping, i.e., periods of nymphal growth and adult emergence are separated. Nymphs of both species feed mainly on detritus, but quantities of coarse particulate organic matter (CPOM) and diatoms are also ingested. Larger nymphs of both species ingest more CPOM and fewer diatoms. This suggests a similar trophic behaviour through their development. For example, they act as collector‐gatherers in their earlier instars and as collector‐gatherers or as shredders in their later instars (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The effect of temperature,darkness, starvation and various food types on growth,survival and reproduction of Helisoma duryi,Biomphalaria alexandrina and Bulinus truncatus (Gastropoda: Planorbidae)

Helisoma duryi has been proposed as a biological control agent in schistosomiasis due to its superiority in laboratory competition experiments with various species of the intermediate host snails. Therefore it was considered important to evaluate the response of this snail species and the intermediate host species, Biomphalaria alexandrina and Bulinus truncatus, to various physical, chemical and biological factors under laboratory conditions in order to obtain information on the similarities in the ecological niches of these species. The factors considered in the present paper are: temperature, darkness, starvation and food. All three species had optimal growth and egg laying at 26–28 °C. Only H. duryi survived for a longer period at 33°C and it was capable of starting egg laying at this temperature although the onset was delayed. However, low temperature (18°C) caused a relatively larger decrease in egg laying of H. duryi than in the other two species. Growth and egg laying was reduced for H. duryi and B. truncatus kept under darkness and B. alexandrina could not tolerate maintenance under darkness. A few days of starvation of juvenile snails had no effect on later growth and egg laying capacity of the survivors, although mortality in B. truncatus was increased. B. alexandrina had a lower tolerance to starvation than the other two species. Egg laying of snails fed only one of the three laboratory food types decreased for all three species in the order: Vov-vov (dog food in dry pellets), Tetramin (fish food) and lettuce. Combinations of lettuce and one or more proteinaceous food types gave optimal growth and egg laying for all three species.     

An exotic parasitoid provides an invasional lifeline for native parasitoids

The introduction of an exotic species may alter food webs within the ecosystem and significantly affect the biodiversity of indigenous species at different trophic levels. It has been postulated that recent introduction of the brown marmorated stinkbug (Halyomorpha halys (Stål)) represents an evolutionary trap for native parasitoids, as they accept H. halys egg masses as a host but produce no viable progeny. Interspecific interactions between European egg parasitoid, Trissolcus cultratus (Mayr), and an Asian parasitoid, Trissolcus japonicus (Ashmead), were assessed by providing egg masses to T. cultratus at various time intervals following the initial parasitization by T. japonicus. The suitability of the host for the parasitoid development was re‐assessed by providing T. cultratus with fresh and frozen egg masses of various ages. The likelihood of T. cultratus being able to attack previously parasitized egg masses was determined by assessing the duration of egg mass guarding behavior by T. japonicus following parasitization. The results of experiments examining the interspecific interactions between a native European egg parasitoid, T. cultratus, and an Asian parasitoid, T. japonicus (a candidate for the biological control of H. halys), showed that the native species can act as facultative hyperparasitoid of the exotic one. Although this is only possible during certain stages of T. japonicus development, the presence of the introduced parasitoid may reduce the impact of the evolutionary trap for indigenous parasitoid species. There is a possibility that the occurrence of facultative hyperparasitism between scelionid parasitoids associated with stinkbugs is common. This resulting intraguild predation could promote conservation and stabilization of natural communities by impacting the diversity and population dynamics of native stinkbugs and their parasitoids (e.g., by allowing native parasitoids to avoid wasting reproductive effort on unsuitable hosts), or reduce success of biological control programs (e.g., by reducing the population size of the exotic parasitoids).     

Three New Species of Gelechiid Moths (Lepidoptera,Gelechiidae) from the Southeastern Regions of the European Part of Russia

Three new species of gelechiid moths (Gelechiidae) are described from the arid regions of the southeastern European part of Russia (Astrakhan and Orenburg provinces): Bryotropha satschkovisp. n., Monochroa aenigmasp. n., and Scrobipalpa achtubicasp. n.

     

The influence of temperature on life history traits in the Iberian slug,Arion lusitanicus

The slug Arion lusitanicus is an invasive species which has recently become established in many European countries and is considered a serious pest, both in agriculture and private gardens. The effect of temperature on growth rate, survival, egg developmental time and hatchability of the slug are reported. The growth rate was positively correlated with temperatures up to 20°C and A. lusitanicus continued (on average) to grow until they die. A model describing how growth depends on temperature was developed, and a field survey found that the predicted growth matched the observed with reasonable accuracy. This study confirms the assumption that A. lusitanicus die after egg laying. Free‐ranging A. lusitanicus has an annual life cycle, but our data show that slugs also possess the ability to live for up to 3 years. The egg developmental time was, like growth, positively correlated with temperature and was shortest at 20°C, but the optimum temperature for egg development, when regarded as the temperature with highest hatchability was found to be 10°C. In conclusion, this study has shown that growth and the life‐history traits, egg developmental time and hatchability, of A. lusitanicus are highly influenced by temperature. However, data also show that temperatures within the range 2–20°C did not influence survival rates to any large degree, and that A. lusitanicus can quickly adjust to changes in temperature. The study provides a number of basic parameters which contribute to the understanding of the population dynamics of A. lusitanicus.