Phylogeny and systematics of the Pachychilidae of mainland South‐East Asia – novel insights from morphology and mitochondrial DNA (Mollusca,Caenogastropoda, Cerithioidea)

Pachychilid gastropods are a conspicuous element of the freshwater macro‐invertebrate fauna of South‐East Asia. In this region, three spatially separated groups of pachychilids can be differentiated mostly by means of their brooding strategy. The largest group comprises about 100 described species and displays an extended Sundaland distribution that ranges from north‐east India in the west to southern China in the east and Borneo in the south‐east. The most conspicuous synapomorphy shared by females is a subhaemocoelic brood pouch in which developing embryos are retained. Mitochondrial phylogenies based on partial sequences of the genes cytochrome oxidase C subunit I (COI) and 16S rRNA (16S) support the monophyly of this group of subhaemocoelic brooders. Amongst them, the two genera Brotia and Paracrostoma form a sister pair of clades both together forming the sister taxon of a third clade. This third clade itself is split into three subclades, which occupy separate ranges except for the overlap of two of them in Borneo. The subclades comprise species from (A) Thailand, Cambodia, and northern Borneo; (B) Java and south‐western Borneo; and (C) Vietnam and southern China. In contrast with their spatial structuring, all species share a widely corresponding anatomy. Characteristic key features are a pallial oviduct with a seminal receptacle and an embryonic shell with a smooth, dome‐like inflated apex. Differences in the histology of the pallial oviduct are not congruent with phylogenetic patterns as suggested by the mitochondrial trees. Given the lack of obvious distinguishing morphological characteristics, all species of the subclades A to C are assigned to a single genus, Sulcospira, with Adamietta as a junior synonym.     

Lineage diversification in a widespread species: roles for niche divergence and conservatism in the common kingsnake, Lampropeltis getula

Niche conservatism and niche divergence are both important ecological mechanisms associated with promoting allopatric speciation across geographical barriers. However, the potential for variable responses in widely distributed organisms has not been fully investigated. For allopatric sister lineages, three patterns for the interaction of ecological niche preference and geographical barriers are possible: (i) niche conservatism at a physical barrier; (ii) niche divergence at a physical barrier; and (iii) niche divergence in the absence of a physical barrier. We test for the presence of these patterns in a transcontinentally distributed snake species, the common kingsnake ( Lampropeltis getula ), to determine the relative frequency of niche conservatism or divergence in a single species complex inhabiting multiple distinct ecoregions. We infer the phylogeographic structure of the kingsnake using a range-wide data set sampled for the mitochondrial gene cytochrome b . We use coalescent simulation methods to test for the presence of structured lineage formation vs. fragmentation of a widespread ancestor. Finally, we use statistical techniques for creating and evaluating ecological niche models to test for conservatism of ecological niche preferences. Significant geographical structure is present in the kingsnake, for which coalescent tests indicate structured population division. Surprisingly, we find evidence for all three patterns of conservatism and divergence. This suggests that ecological niche preferences may be labile on recent phylogenetic timescales, and that lineage formation in widespread species can result from an interaction between inertial tendencies of niche conservatism and natural selection on populations in ecologically divergent habitats.     

Non-invasive determination of plant biomass with microwave resonators

Non-invasive and rapid determination of plant biomass would be beneficial for a number of research aims. Here, we present a novel device to non-invasively determine plant water content as a proxy for plant biomass. It is based on changes of dielectric properties inside a microwave cavity resonator induced by inserted plant material. The water content of inserted shoots leads to a discrete shift in the centre frequency of the resonator. Calibration measurements with pure water showed good spatial homogeneity in the detection volume of the microwave resonators and clear correlations between water content and centre frequency shift. For cut tomato and tobacco shoots, linear correlations between fresh weight and centre frequency shift were established. These correlations were used to continuously monitor diel growth patterns of intact plants and to determine biomass increase over several days. Interferences from soil and root water were excluded by shielding pots with copper. The presented proof of principle shows that microwave resonators are promising tools to quantitatively detect the water content of plants and to determine plant biomass. As the method is non-invasive, integrative and fast, it provides the opportunity for detailed, dynamic analyses of plant growth, water status and phenotype.     

Treeline shifts in the Ural mountains affect soil organic matter dynamics

Historical photographs document that during the last century, forests have expanded upwards by 60–80 m into former tundra of the pristine Ural mountains. We assessed how the shift of the high‐altitude treeline ecotone might affect soil organic matter (SOM) dynamics. On the gentle slopes of Mali Iremel in the Southern Urals, we (1) determined the differences in SOM stocks and properties from the tundra at 1360 m above sea level (a.s.l.) to the subalpine forest at 1260 m a.s.l., and (2) measured carbon (C) and nitrogen (N) mineralization from tundra and forest soils at 7 and 20 °C in a 6‐month incubation experiment. C stocks of organic layers were 3.6±0.3 kg C m^?2 in the tundra and 1.9±0.2 kg C m^?2 in the forest. Mineral soils down to the bedrock stored significantly more C in the forest, and thus, total soil C stocks were slightly but insignificantly greater in the forest (+3 kg C m^?2). Assuming a space for time approach based on tree ages suggests that the soil C sink due to the forest expansion during the last century was at most 30 g C m^?2 yr^?1. Diffuse reflective infrared spectroscopy and scanning calorimetry revealed that SOM under forest was less humified in both organic and mineral horizons and, therefore, contained more available substrate. Consistent with this result, C mineralization rates of organic layers and A horizons of the forest were two to four times greater than those of tundra soils. This difference was similar in magnitude to the effect of increasing the incubation temperature from 7 to 20 °C. Hence, indirect climate change effects through an upward expansion of forests can be much larger than direct warming effects (Δ0.3 K across the treeline). Net N mineralization was 2.5 to six times greater in forest than in tundra soils, suggesting that an advancing treeline likely increases N availability. This may provide a nutritional basis for the fivefold increase in plant biomass and a tripling in productivity from the tundra to the forest. In summary, our results suggest that an upward expansion of forest has small net effects on C storage in soils but leads to changes in SOM quality, accelerates C cycling and increases net N mineralization, which in turn might stimulate plant growth and thus C sequestration in tree biomass.     

Rapid changes in fish community structure and habitat distribution following the precipitation of lake phosphorus with aluminium

1. Fish community structure and habitat distribution of the abundant species roach, perch and ruffe were studied in Lake Nordborg (Denmark) before (August 2006) and after (August 2007) aluminium treatment to reduce internal phosphorus loading. 2. Rapid changes in fish community structure, abundance and habitat distribution occurred following a decline in in‐lake phosphorus concentrations from 280 to 37 μg P L^?1 and an increase in Secchi depth transparency from 1.1 to 1.9 m (August). The proportion of perch in overnight gill net catches increased, whilst roach decreased, and the average weight of all key species increased. 3. The habitat distribution of perch and roach changed from a high proportion in the upper pelagic and littoral zones in 2006, towards enhanced proportions in the deeper pelagic and profundal zone in 2007. The abundance of large‐bodied zooplankton increased and the abundance of benthic invertebrates decreased in the same period, suggesting that the habitat shift was not induced by food limitation. 4. Ruffe shifted from the littoral and upper profundal zones towards the deep profundal zone, likely reflecting an increased predation risk in the littoral zone and better oxygen conditions in the deep profundal. 5. Our results indicate that enhanced risk of predation in the upper pelagic and the littoral zones and perhaps improved oxygen concentrations in the deeper profundal zone at decreasing turbidity are responsible for the observed habitat shift. The results indicate that fish respond rapidly to changes in nutrient state, both in terms of community structure and habitat use.     

The impact of an ant–aphid mutualism on the functional composition of the secondary parasitoid community

1. Mutualistic and antagonistic interactions, although often studied independently, may affect each other, and food web dynamics are likely to be determined by the two processes working in concert. 2. The structure, and hence dynamics, of food webs depends on the relative abundances of generalist and specialist feeding guilds. Secondary parasitoids of aphids can be divided into two feeding guilds: (i) the more specialised endoparasitoids, which attack the primary parasitoid larvae in the still living aphid, and (ii) the generalist ectoparasitoids, which attack the pre‐pupa of the primary or secondary parasitoid in the mummified aphid. 3. We studied the effect of an ant–aphid mutualism on the relative abundance of these two functional groups of secondary parasitoids. We hypothesised that generalists will be negatively affected by the presence of ants, thus leading to a greater dominance of specialists. 4. We manipulated the access of ants (Lasius niger) to aphid colonies in which we placed parasitised aphids. Aphid mummies were collected and reared to determine the levels of endo‐ and ecto‐secondary parasitism. 5. When aphids were attended by L. niger the proportion of secondary parasitism by ectoparasitoids dropped from 26 to 8% of the total number of parasitised aphids, with Pachyneuron aphidis most strongly affected, while endoparasitoids as a group did not respond. However, among these Syrphophagus mamitus profited from ant attendance becoming the dominant secondary parasitoid, while parasitisation rates of Alloxysta and Phaenoglyphis declined. 6. The shift to S. mamitus as dominant secondary parasitoid in ant‐attended aphid colonies is likely due to the behavioural plasticity of this species in response to ant aggression, and a release from tertiary parasitism by generalist ectoparasitoids. 7. The reduction of secondary parasitism by generalist ectoparasitoids reduces the potential for apparent competition among primary parasitoids with consequences for the dynamics of the wider food web.     

The larval head of Nevrorthidae and the phylogeny of Neuroptera (Insecta)

External and internal head structures of larvae of Nevrorthidae were described in detail. The results were compared to conditions found in other representatives of Neuroptera and the other two neuropterid orders. The cladistic analysis supported the monophyly of Neuroptera, Neuroptera exclusive of Nevrorthidae, Hemerobiiformia, and Myrmeleontiformia. Neuroptera exclusive of Nevrorthidae are supported by the formation of an undivided postmentum and the presence of cryptonephric Malpighian tubules. The highly specialized articulation of the neck (Rollengelenk) and the absence of a salivary duct are autapomorphies of Nevrorthidae. Ithonidae and Polystoechotidae form a clade and are the sister group of the remaining Hemerobiiformia, which are characterized by the complete lack of a gula and a terminal filament of the antenna. Within this lineage, a clade comprising Mantispidae, Dilaridae, Berothidae, and Rhachiberothidae is well supported. Larvae of Myrmeleontiformia are characterized by a complex transformation of head structures, with a hypostomal bridge, a small triangular gula, largely reduced maxillary grooves, and anteriorly shifted posterior tentorial grooves. The slender finger‐like mid‐dorsal apodeme is another autapomorphy of the group. Psychopsidae are placed as the sister group of the remaining Myrmeleontiformia, which are characterized by a conspicuous, protruding ocular region (often less distinct or even absent in Nemopteridae). Ascalaphidae are the sister group of Myrmeleontidae. Larvae of both families share the fusion of the tibia and tarsus in the hind leg. The larval characters analysed were not sufficient for full resolution of the myrmeleontiform and hemerobiiform lineages. The position of several families such as Osmylidae, Sisyridae, and Coniopterygidae remains uncertain. The results are in agreement with an aquatic ancestor of Neuroptera and secondarily acquired terrestrial habits within the lineage (Neuroptera exclusive of Nevrorthidae), and another invasion of the aquatic environment by Sisyridae. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 533–562.     

The female postabdomen and internal genitalia of the basal moth genus Agathiphaga (Insecta: Lepidoptera: Agathiphagidae): morphology and phylogenetic implications

The female postabdomen of Agathiphaga vitiensis terminates in a telescope‐type extensible oviscapt with an apial ‘oviscapt probe’ composed of fused segments behind VIII. Exceptionally within the Lepidoptera two pairs of long ‘anterior apophyses’ arise from segment VIII, from the dorsum and venter. Agathiphaga has the most elaborate postabdominal musculature recorded from female Lepidoptera, comprising 24 muscle sets of which nine may be family autapomorphies. Apophysis musculature does not permit unambiguous homologizing of the single anterior apophysis in Lepidoptera–Glossata with either the dorsal or ventral pair in Agathiphaga, but is compatible with an interpretation of the glossatan anterior apophyses as a composite formation. Nine muscle sets shared with rhyacophilid caddisflies are ascribed to the amphiesmenopteran ground plan. The spermathecal duct represents an intermediate stage between the simple type present in Micropterigidae and the ‘two‐compartment type’ characteristic of almost all other Lepidoptera. The spermatheca has no lagena. The bursa copulatrix is small and simple. Accessory glands are very large, simple sacs. There are 40 + ovarioles per ovary. A terminal cloaca is extremely short. The numerous ovarioles potentially support a sister‐group relationship between Agathiphagidae and all other Lepidoptera, whereas the spermathecal duct histology supports the alternative conservative placement of the family as sister group of all nonmicropterigid Lepidoptera. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 159 , 905–920.     

Biogeography meets conservation: the genetic structure of the endangered lycaenid butterfly Lycaena helle (Denis & Schiffermüller, 1775)

Cold‐adapted species are thought to have had their largest distribution ranges in central Europe during the glacial periods. Postglacial warming caused severe range shifts of such taxa into higher latitudes and altitudes. We selected the boreomontane butterfly Lycaena helle (Denis & Schiffermüller, 1775) as an example to demonstrate the genetic effects of range changes, and to document the recent status of highly fragmented remnant populations. We analysed five polymorphic microsatellite loci in 1059 individuals sampled at 50 different localities scattered over the European distribution area of the species. Genetic differentiation was strong among the mountain ranges of western Europe, but we did not detect similarly distinct genetic groups following a geographical pattern in the more eastern areas. The Fennoscandian populations form a separate genetic group, and provide evidence for a colonization from southern Finland via northern Scandinavia to south‐central Sweden. Species distribution modelling suggests a large extension of the spatial distribution during the last glacial maximum, but highlights strong retractions to a few mountain areas under current conditions. These findings, combined with our genetic data, suggest a more or less continuous distribution of L. helle throughout central Europe at the end of the last ice age. As a consequence of postglacial warming, the species retreated northwards to Fennoscandia and escaped increasing temperatures through altitudinal shifts. Therefore, the species is today restricted to population remnants located at the mountain tops of western Europe, genetically isolated from each other, and evolved into genetically unique entities. Rising temperatures and advancing habitat destruction threaten this wealth of biodiversity. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 155–168.