Differences in the onset of laying between island and mainland Mediterranean Blue Tits Parus caeruleus: phenotypic plasticity or genetic differences?

Blue tits Parus caeruleus breeding in deciduous or in evergreen woodlands on the mainland of Europe start to lay 3–4 weeks earlier than Blue Tits on the island of Corsica breeding in evergreen woodlands. A similar difference in average laying date between the two Blue Tit populations has been found in a relatively small sample of captive birds held in outdoor aviaries on the mainland. To provide data on the habitat contrast in Corsica for comparison with that on the mainland, a new study area was started in one of the few deciduous woodlands on Corsica. In addition, new data on laying dates of captive Blue Tits were gathered to increase the sample size of independent pairs in aviaries. This study shows that the habitat effect (deciduous ν evergreen woodland) on the average laying date of Blue Tits is relatively small in comparison with the geography effect (European mainland ν Corsica). The laying date differences between mainland and insular Blue Tits persisted whatever the type of habitat (deciduous, evergreen or outdoor aviaries on the mainland). The data support the hypothesis that the observed differences in the onset of laying between the mainland and insular Blue Tits were mainly influenced by genetic effects and relatively little by non-genetic maternal effects of by genotype—environment interactions.     

Survival costs of reproduction in the blue tit (Parus caeruleus): a role for blood parasites?

One of the central tenets in life-history theory is that there is a trade-off between current and future reproduction (i.e. a cost of reproduction). The mechanism for this cost of reproduction is, however, largely unknown. One hypothesis is that the high workload during reproduction compromises resistance to parasites and that the resulting increase in parasitaemia has negative effects on the prospects of future survival. Although empirical evidence for a negative relationship between reproductive effort and parasite resistance exists, the causal relationships between reproductive effort, parasite resistance and future reproduction are still unclear. We use a path analytical approach to investigate whether a change in parasite resistance (as measured by intensities of infections by the blood parasite Haemoproteus) after manipulation of reproductive effort, translates into altered survival in female blue tits. Our results show a negative relationship between reproductive effort and parasite resistance, although evident only in first-year breeders. Moreover, we found survival costs of reproduction in first-year breeders. These costs were, however, not mediated by the blood parasite studied.     

Are island and mainland biotas different? Richness and level of generalism in parasitoids of a microlepidopteran in Macaronesia

Island communities are exposed to several evolutionary and ecological processes that lead to changes in their diversity and structure compared to mainland biotas. These phenomena have been observed for various taxa but not for parasitoids, a key group in terms of community diversity and functioning. Here we use the parasitoid communities associated with the moth Acroclita subsequana (Lepidoptera: Tortricidae) in the Macaronesian region, to test whether species richness differs between islands and mainland, and whether island parasitoid faunas are biased towards generalist species. Host larvae were collected on several islands and adjacent mainland, carefully searched for ectoparasitoid larvae and dissected to recover any endoparasitoids. Parasitoids were classified as idiobionts, which usually have a wide host range (i.e. generalists), or koinobionts that are considered specialists. Mainland species richness was lower than expected by chance, with most of the species being koinobionts. On the other hand, island communities showed a greater proportion of idiobiont species. Overall parasitism rates were similar between islands and mainland, but islands had higher rates of parasitism by idiobionts than expected by chance, and mainland areas showed the highest koinobiont parasitism rates. These results suggest that island parasitoid communities are dominated by generalists, in comparison to mainland communities. Several hypotheses may explain this pattern: (1) generalist parasitoids might have better dispersal abilities; (2) they may be less constrained by ‘sequential dependencies’; and (3) island parasitoids probably have fewer competitors and/or predators, thus favouring the establishment of generalists. New studies including multiple hosts, other habitats, and/or more islands are necessary to identify which of these processes shape island parasitoid communities.     

Contrasting levels of extra-pair paternity in mainland and island populations of the house sparrow (Passer domesticus): is there an 'island effect'?

Despite the many studies that have investigated the genetic mating system of socially monogamous birds, very little is known about the underlying causes of extra-pair paternity and few studies have attempted to test those hypotheses which have been suggested. This study describes die analysis of die genetic mating system of two populations of the house sparrow [Passer domesticus) , and uses the results from four other populations to test existing hypodieses using an intra-specific comparative approach. The parentage analysis was conducted using a combination of published and newly presented microsatellite loci isolated from the house sparrow. One population in Kentucky, U.S.A. was found to contain what may be considered to be a typical level of extra-pair paternity for mis species (10.5%, 19/185 offspring). The second, a population on the island of Lundy, UK, exhibited a very low level (1.3%, 4/305 offspring), significandy lower dian that in all the other populations studied so far. The finding of such diverse rates of extra-pair paternity, along with the existing estimates from ofher populations, has allowed us to test the effects of breeding density and genetic variation on die level of extra-pair paternity. We found no effect of either factor on the frequency of extra-pair paternity in the house sparrow, leaving the cause of this variation open to fresh ideas.     

Traplining in bumblebees (Bombus impatiens): a foraging strategy’s ontogeny and the importance of spatial reference memory in short-range foraging

To test the relative importance of long-term and working spatial memories in short-range foraging in bumblebees, we compared the performance of two groups of bees. One group foraged in a stable array of six flowers for 40 foraging bouts, thereby enabling it to establish a long-term memory of the array, and adjust its spatial movements accordingly. The other group was faced with an array that changed between (but not within) foraging bouts, and thus had only access to a working memory of the flowers that had been visited. Bees in the stable array started out sampling a variety of routes, but their tendency to visit flowers in a repeatable, stable order (“traplining”) increased drastically with experience. These bees used shorter routes and converged on four popular paths. However, these routes were mainly formed through linking pairs of flowers by near-neighbour movements, rather than attempting to minimize overall travel distance. Individuals had variations to a primary sequence, where some bees used a major sequence most often, followed by a minor less used route, and others used two different routes with equal frequency. Even though bees foraging in the spatially randomized array had access to both spatial working memory and scent marks, this manipulation greatly disrupted foraging efficiency, mainly via an increase in revisitation to previously emptied flowers and substantially longer search times. Hence, a stable reference frame greatly improves foraging even for bees in relatively small arrays of flowers.     

What are the consequences of being a downy oak (quercus pubescens) or a holm oak (Q. ilex) for breeding blue tits (Parus caeruleus)?

By comparison with deciduous oaks, the lower yearly production of new leaves in sclerophyllous oaks is hypothesized to have several consequences on animal communities. In particular, the production of arthropod communities that feed upon the leaves should be lower in sclerophyllous than in deciduous oaks, this causing changes in breeding patterns and the demographic balance in insectivorous birds. Studies in both deciduous and sclerophyllous habitats in southern France have shown that: 1) the spring development of new leaves occurs later and more slowly in sclerophyllous than in deciduous oaks, 2) the biomass of caterpillars is much lower in sclerophyllous oak forests, and 3) there is a large variation in life history traits of the Blue Tit depending in which type of habitat they breed. Laying date occurs later and clutch size is lower in sclerophyllous habitats than in deciduous habitats. The evolution of life history traits is discussed according to whether poor sclerophyllous habitats are isolated (e.g. on Corsica) or are parts of landscapes including both habitat types.     

Effects of adaptive predatory and anti-predator behaviour in a two-prey—one-predator system

Summary Two prey populations that share a common predator can interact indirectly by causing changes in the predator's foraging behaviour. Previous work suggests that adaptive choice of prey by the predator usually has two related consequences: (i) the predation rate on a particular prey species increases with the relative and/or absolute abundance of that prey; and (ii) increases in either prey population produce a short-term increase in the fitness of the other prey (short-term indirect mutualism between prey). This paper investigates how these two consequences are changed if the prey exhibit adaptive anti-predator behaviour. In this case, the predation rate on a particular prey often decreases as the prey's density increases. The predator then usually exhibits negative switching between prey. However, the presence of adaptive antipredator behaviour does not change the short-term mutualism between prey. In this case, as a prey becomes less common, it achieves a larger growth rate by reducing its anti-predator effort. These results imply that observations of the relationship between prey density and predation rate cannot be used to infer the nature of the behavioural indirect effect between prey that share a predator.     

Morphological and anatomical changes in the roots of apple seedlings treated with morphactin IT 3456 and α-naphthalene acetic acid (NAA)

On the roots of the unchilled apple seedlings treated with morphactin many deformed adventitious shoots were formed, whereas when the roots were dipped in the mixture of morphactin and NAA more adventitious roots were produced than when only NAA was used. The growth of these lateral roots was greatly inhibited. Similar interaction of NAA with morphactin in the development of roots was obtained when the chilled seedlings were treated with these growth regulators before the buds developed. The sections of the roots from all the treatments were made and the anatomy studied.     

Morphological evolution in the variable resin-producing Detarieae (Fabaceae): do morphological characters retain a phylogenetic signal?

Background and Aims

Previous molecular phylogenetic studies disagree with the informal generic-level taxonomic groups based on morphology. In this study morphological characters in the caesalpinioid clade Detarieae are evaluated within a phylogenetic framework as a means of better understanding phylogenetic relationships and morphological evolution.

Methods

Morphological characters were observed and scored for representative species of Detarieae focusing on the resin-producing genera. Phylogenetic analyses were carried out with morphological characters alone and then combined with DNA sequences.

Key Results

Despite a high level of homoplasy, morphological data support several clades corresponding to those recovered in molecular phylogenetic analyses. The more strongly supported clades are each defined by at least one morphological synapomorphy. Several characters (e.g. apetaly) previously used to define informal generic groups evolved several times independently, leading to the differences observed with the molecular phylogenetic analyses. Although floral evolution is complex in Detarieae some patterns are recovered.

Conclusions

New informal taxonomic groupings are proposed based on the present findings. Floral evolution in the diverse Detarieae clade is characterized by a repeated tendency toward zygomorphy through the reduction of lateral petals and toward complete loss of petals.Key words: Caesalpinioideae, Detarieae, floral evolution, Leguminosae, morphology, phylogeny, resins, taxonomy     

Nuclear and mitochondrial genetic variation in the Yanomamö: a test case for ancient DNA studies of prehistoric populations

Ancient DNA provides a potentially revolutionary way to study biological relationships in prehistoric populations, but genetic patterns are complex and require careful interpretation based on robust, well-tested models. In this study, nuclear and mitochondrial markers were compared in the Yanomam?, to assess how well each data set could differentiate among closely related groups. The villages selected for the study share a recent fission history and are closely related to each other, as would likely be the case among prehistoric peoples living in the same valley or region. The Yanomam? generally practice village-level endogamy, but some migration and gene flow are known to occur between villages. Nuclear and mitochondrial DNA data were compared using F-statistics and genetic distance analyses. The nuclear data performed as expected, males and females from the same village were similar, and the villages were genetically distinct, with the magnitude of genetic differences correlated with historical relationship. However, mtDNA analyses did not yield the expected results. The genetic distances between villages did not correlate with historical relationship, and the sexes were significantly different from each other in two villages. Both the Lane and Sublett and the Spence methods, used to test for archaeological residence patterns, were consistent with endogamy. Hence, ancient DNA can, in principle, provide us with a unique opportunity to study genetic structure and gene flow in archaeological populations. However, interpretations, particularly those based on single loci such as mitochondrial DNA, should be cautious because sex-specific migration and sampling issues may have dramatic effects.     

Loss of nervous system complexity – Morphological analyses shed light on the neuronal evolution in Myzostomida (Annelida)

Myzostomida are putatively nested within the errant Annelida and exhibit a unique morphology. The latter fact might possibly be related to their long host-dependent radiation. Hence, an incomplete segmentation, lack of prominent sensory structures in adults and a dorso-ventrally flattened body are just some examples. Although numerous investigations of the nervous system exist for myzostomids, detailed ultrastructural as well as histological examinations of neuronal structures are lacking so far. Therefore, we investigate the nervous system of Myzostoma cirriferum Leuckart, 1836 using a comparative approach including paraffin histology, serial semi-thin sections, immunohistochemistry and ultrastructural investigations. Our analyses reveal a lack of complexity within the anterior-most neuronal condensation (herein called brain) of adult specimens. Hence, prominent tracts or glomeruli are absent, and a glial layer surrounding the brain or radial-like glial cells are lacking. Nevertheless, the ultrastructure of the ventral nervous system is comparable to other Errantia. Therefore, our investigations hint towards a reduction of neuronal complexity in Myzostomida. Additionally, an ontogenetic simplification seems plausible, although further investigations are necessary to verify such a hypothesis. A simplification of neuronal structures due to a drastic change in lifestyle was so far mainly observed for basally branching annelid clades.     

Nomadic behaviour and colony fission in a cooperative spider: life history evolution at the level of the colony?

The concept of colony-level life history evolution is introduced for the cooperative spiders by describing the life cycle and demography of Atbuhna binotata (Araneae: Dictynidae), a species living in groups containing up to several dozen adult females plus their offspring. In a life cycle remarkably similar to that of army ants, the colonies of A binotata were found to reproduce by fission and to alternate nomadic and sedentary phases in tight association with their internal demography. Colonies of other cooperative spiders, on the other hand, remain stationary as they grow for a number of generations before producing propagules that are relatively small subsets of the maternal colony. It is suggested that A. binotata!% peculiar life cycle may have unfolded as a consequence of the two-dimensional architecture of its nests. Expanding two-dimensional nests may fragment more easily than the three-dimensional nests characteristic of other species. A long distance group migration or nomadic phase, described here for the first time for a spider, may have followed as a mechanism to cope with potential disadvantages of fission while selecting for strict synchronization of individual life cycle stages within the nests. It is shown, however, that, as in other cooperative spiders, A. binotatd% sex ratio is also highly female biased. The theoretical implications of biased sex ratios in a species with fissioning colonies are briefly discussed.     

Terrigenous sediment-dominated reef platform infilling: an unexpected precursor to reef island formation and a test of the reef platform size–island age model in the Pacific

Low-lying coral reef islands are considered highly vulnerable to climate change, necessitating an improved understanding of when and why they form, and how the timing of formation varies within and among regions. Several testable models have been proposed that explain inter-regional variability as a function of sea-level history and, more recently, a reef platform size model has been proposed from the Maldives (central Indian Ocean) to explain intra-regional (intra-atoll) variability. Here we present chronostratigraphic data from Pipon Island, northern Great Barrier Reef (GBR), enabling us to test the applicability of existing regional island evolution models, and the platform size control hypothesis in a Pacific context. We show that reef platform infilling occurred rapidly (~4–5 mm yr⁻¹) under a “bucket-fill” type scenario. Unusually, this infilling was dominated by terrigenous sedimentation, with platform filling and subsequent reef flat formation complete by ~5000 calibrated years BP (cal BP). Reef flat exposure as sea levels slowly fell post highstand facilitated a shift towards intertidal and subaerial-dominated sedimentation. Our data suggest, however, a lag of ~1500 yr before island initiation (at ~3200 cal BP), i.e. later than that reported from smaller and more evolutionarily mature reef platforms in the region. Our data thus support: (1) the hypothesis that platform size acts to influence the timing of platform filling and subsequent island development at intra-regional scales; and (2) the hypothesis that the low wooded islands of the northern GBR conform to a model of island formation above an elevated reef flat under falling sea levels.

     

The phylogeny and evolution of thePterygodium—Corycium complex (Coryciinae,Orchidaceae)

The leaf-anatomy, palynology, seed-morphology, vegetative morphology and especially the highly complicated floral morphology of theCoryciinae s. str. (Diseae: Orchidoideae: Orchidaceae) are described and illustrated in detail. On the basis of these characters the presumed phylogeny, based on a rigorous cladistic analysis, is presented. The cladistic biogeographical analysis of theCoryciinae s. str. shows that it is a member of the Afrotemperate Track, with a pattern of vicariance events typical of the members of this track. An analysis of the patterns of speciation shows that allopatric speciation appears to be rare, and that parapatric speciation across edaphic boundaries may be the most important factor. Proceeding from the information presented, a new classification of the group is proposed in which we recognize the four generaCeratandra, Evotella, Pterygodium andCorycium. The new monotypic genusEvotella comprises a species originally described asPterygodium rubiginosum. The three species of the genusAnochilus are transferred toCorycium andPterygodium. P. magnum, which was originally described asPterygodium but was transferred toCorycium lately, is placed in a monotypic section ofPterygodium.     

Progressive changes in the structure and dynamics of the phytoplankton community along a pollution gradient in a lowland river — a multivariate approach

The phytoplankton of the River Lujan (Buenos Aires, Argentina) was studied for a period of 18 months, together with physical and chemical variables, in relation to a pollution gradient. 167 taxa were recorded within a seasonal succession characterized by dominance of diatoms with a brief summer green algae facies. A combination of several biotic indices and multivariate analysis was employed to assess the impact of pollution on the phytoplankton community. The biotic indices used were species diversity and richness, algal quotients (green algae/diatom ratio, Centrales/Pennales ratio) and the SD succession rate index. Multivariate procedures included cluster analysis and ordination by PCA of both species and samples, stepwise discriminant analysis and multiple discriminant analysis of variance (MANOVA). Results indicate that community dynamism is attenuated at the more polluted sites, concomitant with an increased predominance of a broad-tolerance algal assemblage, co-dominated by Cyclotella meneghiniana and Nitzschia stagnorum. The changes in the community structure and dynamics described herein involved alterations in the distribution and relative proportions of the algae, rather than modifications in the basic species composition. These changes may not be readily detectable by methods which over-simplify the ecological information, such as systems of indicator species and biotic indices, designed to assess the degree of pollution. The suitability of multivariate analysis and biotic indices in river phytoplankton studies is further discussed.     

Analysis and evolution of water quality of the upper Váh River (northern Slovakia) by long-term changes in the community structure of ciliates (Protista: Ciliophora)

A long-term monitoring of the upper Váh River was carried out in order to evaluate evolution of water quality by means of ciliate taxocoenoses. One sampling station (Lisková) was located upstream of the pulp and paper mill in the town of Ru?omberok, while two stations (Bystrá and Stankovany) were situated downstream of Ru?omberok. Benthic samples were collected three times a year at each station during 2004–2011. This long-term study enabled us to assemble a comprehensive checklist of ciliates recorded in the upper Váh, and to characterize and compare the ciliate communities in the investigated watercourse. The saprobic index and valency analysis of the ciliate communities allowed us to quantify organic input and to evaluate changes in the saprobity of the upper Váh. The saprobic index ranged from 2.45 to 3.66 corresponding to the quality classes II–IV. Further, there was a prevalence of the α- and β-mesosaprobic levels, but during some periods the polysaprobic level increased along with the decrease of the β-mesosaprobic level. Beside the organic pollution, toxic contaminations were also noticed several times in the studied watercourse. This was documented by a significant drop in the species diversity and abundance of ciliates as well as by various morphological malformations and movement disorders of ciliates and other microorganisms. However, the negative effect of toxic and/or organic pollution wore off relatively quickly, indicating a good self-purification capability of the river.     

Palaeoecological evolution of a spring-fed fen in Pawłów (eastern Poland)

A continuous record of sedimentation in spring-fed fens makes them suitable for detailed palaeoenvironmental studies. A newly investigated cupola spring-fed fen (Paw?ów site), located in the Lublin chalkland, eastern Poland, was the object of our study. This special karst region is characterised by the occurrence of Upper Cretaceous carbonate rocks in the substratum. Sedimentological observations indicated strong variability of biogenic-carbonate series in the deposits (=peat-tufa rhythmite), reflects changes of accumulation conditions (oxidising versus reducing), resulting from alternate occurrence of warmer and cooler periods. Difficulties in pollen analysis due to oxidising conditions necessitate a multidisciplinary approach for palaeoenvironmental reconstruction. We used a multidisciplinary approach (sedimentological, palaeobotanical, geochemical analyses and radiocarbon dating) to determine the main evolutionary stages of this unique fen ecosystem and to discuss the role of local or/and regional factors in its development. Pollen and plant macrofossil analyses, supported by radiocarbon dating, proved that the bottom part of the cores represents the Late Glacial–Early Holocene stages of the fen development. A comparative analysis of palaeoenvironmental data showed close resemblance between the Paw?ów fen and the earlier studied fens in eastern Poland and Central-Eastern Europe, and the connection between their development and supraregional hydrological-climatic factors. The results indicated also the influence of the morphological position of such a type of ecosystem on the development of a continuous deposit succession. The occurrence of a river valley in close proximity of the Paw?ów site resulted in the lack of tufa deposits from the Atlantic period, because of an erosional phase in the river valley.