An ecosystem model-based estimate of changes in water availability differs from water proxies that are commonly used in species distribution models

Aim  To assess whether the water availability measures commonly used in species distribution models might be misleading because they do not account for the hydrological effects of changes in vegetation structure and functioning.
Location  Europe.
Methods  We compared different methods for estimating water availability in species distribution models with the soil water content predicted by a process-based ecosystem model. The latter also accounted for the hydrological effects of dynamic changes in vegetation structure and functioning, including potential physiological effects of increasing CO₂.
Results  All proxies showed similar patterns of water availability across Europe for current climate, but when projected into the future, the changes in the simpler water availability measures showed no correlation with those projected by the more complex ecosystem model, even if CO₂ effects were switched off.
Main conclusions  Results from species distribution modelling studies concerning future changes in species ranges and biodiversity should be interpreted with caution, and more process-based representations of the water balance of terrestrial ecosystems should be considered within these models.     

SEX‐SPECIFIC CELL SURFACE STRUCTURE OF ANISOGAMETES: MORPHOLOGICAL CHANGES DURING FERTILIZATION OF BRYOPSIS MAXIMA (ULVOPHYCEAE,CHLOROPHYTA) REVEALED BY ULTRA–HIGH‐RESOLUTION FIELD EMISSION SEM1

Cell surfaces of biflagellate gametes and their morphological changes during fertilization of Bryopsis maxima Okamura were observed using a high‐resolution field emission scanning electron microscope. Male gametes have broad and narrow faces, which are divided into at least five morphologically distinct regions: 1) the apical plate is a plate‐like structure that is approximately 380–530 nm long and approximately 190 nm wide, in the center of the papilla and slightly protruded from the plasma membrane; 2) strips are smooth materials on ridges that originate from the basal part of the papilla and extend downward; 3) the lateral belt is a belt‐shaped structure on the center of the narrower faces; 4) the flagellar surface; and 5) the other region of the cell body has a fine‐grained appearance. In contrast, the entire female gamete surface is rough because of many granular or amorphous cell coats on the plasma membrane. When both gametes were mixed together, the initial fusion proceeded between the broader face of the male gamete and the anterior side of the female one near the basal bodies. Morphology of the male gamete's cell surface changed gradually as fusion proceeded and was covered by the granular materials; that surface closely resembled those of female gametes except for the apical plate. It was present until the planozygote attached itself to the substrate by the papilla. It finally disappeared after settlement. Therefore, these results indicate that gametes of B. maxima have sex‐specific surface structures that change their morphology during fertilization and settlement.     

Profitable self-superparasitism in an infanticidal parasitoid when conspecifics are present: self-superparasitism deters later attackers from probing for infanticide

Abstract.  1. To reveal the profitability of self-superparasitism when conspecifics are present, the total combined fitness returns from the first and second ovipositions under triple parasitism were compared with fitness returns from the first oviposition under double parasitism, using the small brown hopper Laodelphax striatellus and its semi-solitary infanticidal parasitoid Echthrodelphax fairchildii .
2. The total combined survival rate of the first and second comers under triple parasitism with oviposition intervals of 1/24 h (where 1 and 24 h represent the first-to-second and second-to-third oviposition intervals respectively) was nearly double the survival rate of the first comer under double parasitism with a 25-h oviposition interval, although there was no difference between these triple and double parasitisms in terms of head width and developmental time. Under the conditions of other oviposition intervals, self-superparasitism produced null (1/1- and 24/24-h intervals) or negative fitness returns (24/1-h intervals). This suggests that self-superparasitism on hosts that were self-parasitised 1 h previously is profitable when conspecifics are present.
3. When the female parasitoid laid an egg on a host harbouring the earlier comer(s) on the non-oviposition side, she often probed the non-oviposition side for infanticide, i.e. killing the first offspring. When the first and second comers were on different sides, the probing frequency at the third oviposition in triple parasitism with 1/24-h oviposition intervals was lower than that at the second oviposition in double parasitism with a 25-h oviposition interval. This difference was responsible for the above difference in survival rate between the triple and double parasitisms.     

Why is there no sperm competition in a pipefish with externally brooding males? Insights from sperm activation and morphology

Nerophis ophidion sperm activation and morphology were investigated with the aim of explaining the apparent lack of sperm competition in this syngnathid with externally brooding males. Nerophis ophidion sperm were activated by a mixture of ovarian fluid and sea water, but not by sea water alone. This indicated that sperm were not shed into the water but needed to be released near the eggs, which probably restrained sperm competition.     

Effect of nitrogen fertilization of corn on the development, survivorship, fecundity and body weight of Peregrinus maidis (Hom., Delphacidae)

Abstract:  Corn plants, Zea mays L. cv. Saccharata 'Guardian' fertilized with low (100 mg N/l), medium (300 mg N/l) and high (500 mg N/l) nitrogen doses at three times per week were used to study the effect of foliar nitrogen on the development, survivorship, reproduction, intrinsic rate of increase and adult body weight of Peregrinus maidis (Ashmead), a serious pest and the vector of maize stripe tenuvirus and maize mosaic rhabdovirus in tropical and subtropical areas. The results showed that the higher nitrogen treatments resulted in the higher nitrogen concentrations in the plants. The insects that developed on corn plants receiving more nitrogen had a significantly shorter development time and higher immature survival rate and laid significantly more eggs. Plants with higher nitrogen concentration also resulted in significantly greater adult mass. Heavier body weight is advantageous because heavier adult females have greater daily oviposition rates than lighter ones. These life history parameters as well as population intrinsic rate of increase were positively correlated with the nitrogen levels in the treated plants. The differences of adult longevity and preoviposition period among different nitrogen treatments were also significant; however, no significant correlation was found between the nitrogen fertilization rate and adult longevity, as well as preoviposition period.     

Eyespot behavior during the fertilization of gametes in Ulva arasakii Chihara (Ulvophyceae, Chlorophyta)

Behavior of the eyespots during the fertilization of Ulva arasakii Chihara was studied using field emission scanning electron microscopy (FE‐SEM). FE‐SEM enabled the visualization of the eyespot of biflagellate male and female gametes. The smaller male gamete has one protruded smaller (1.3 ± 0.15 μm× 1.0 ± 0.29 μm) eyespot and the larger female gamete has a larger (1.6 ± 0.2 μm× 1.1 ± 0.13 μm) one on a posterior position of the cell. The cell membrane over the eyespot region is relatively smooth compared to other parts of the cell body and exhibits hexagonal arranged lipid globules. Because the size of the cell and the morphology of the eyespot are different between male and female gametes, we could follow the fate of the eyespots during the fertilization. The initial cytoplasmic contact and fusion of the gametes takes place at their anterior end, slightly posterior to the flagellar base. The morphology of the fusing gametes followed two clearly distinguishable patterns. About half the gamete pairs lie side‐by‐side with their longitudinal axes nearly parallel, while the rest are oriented anti‐parallel to each other. In all cases, the larger female gamete fused along the same side as the eyespot, while the smaller male gamete fused along the side away from its eyespot. As fusion proceeds, the gamete pair is transformed into the quadriflagellate planozygote, in which the eyespots are positioned side‐by‐side on the region of cell fusion. These observations indicated that the opposite positioning of the eyespot relative to the cell fusion site in male and female gametes is important for the proper arrangement of the eyespots in the planozygote. The significance of this feature in advanced green algae is briefly discussed.     

Biomass and compositional responses of ectomycorrhizal fungal hyphae to elevated CO2 and nitrogen fertilization

The extramatrical mycelia (EMM) of ectomycorrhizal fungi make up a large proportion of the microbial diversity and biomass in temperate forest soils. Thus, their response to elevated CO(2) can have large effects on plant nutrient acquisition and carbon movement through forests. Here, the effects of CO(2) and nitrogen (N) fertilization on EMM biomass and community structure in Pinus taeda forest plots were examined using sand-filled mesh bags buried in the field, the contents of which were analyzed by phospholipid fatty acid (PLFA) and DNA sequencing. A total of 2138 sequences comprising 295 taxa were recovered; most (83.5%) were from ectomycorrhizal fungal taxa. No biomass increase was detected in elevated CO(2) plots relative to control plots, but individual taxa responded to both CO(2) and N fertilization, four of the six most abundant taxa were less frequent in N-fertilized plots. Thelephoroid and athelioid taxa were both frequent and abundant as EMM, and thelephoroid richness was extremely high. Russula and Cortinariaceae taxa were less abundant and boletoid taxa were more abundant as EMM relative to ectomycorrhizas. The EMM community, sampled across seasons and years, was dynamic with a high degree of interspecific variation in response to CO(2) enrichment and N fertilization.     

Early predictors of self-biting in socially-housed rhesus macaques (Macaca mulatta)

The development of self-biting behavior in captive monkeys is little understood and poses a serious risk to their well-being. Although early rearing conditions may influence the expression of this behavior, not all animals reared under similar conditions self-bite. The purpose of this study was to examine the effects of three rearing conditions on biting behavior and to determine whether early infant behavior can predict later self-biting. The subjects were 370 rhesus macaques born at the National Institutes of Health (NIH) Animal Center between 1994 and 2004. They were reared under three conditions: mother-reared in social groups (n=183), peer-reared in groups of four (n=84), and surrogate-peer-reared (n=103). Significantly more surrogate-peer-reared animals self-bit compared to peer-only or mother-reared animals. There was no sex difference in self-biting, but this result may have been affected by a sex bias in the number of observations. The durations of behaviors exhibited by the surrogate-peer-reared subjects were recorded in 5-min sessions twice a week from 2 to 6 months of age while the animals were in their home cages and play groups. In the play-group situation, surrogate-peer-reared subjects who later self-bit were found to be less social and exhibited less social clinging than those that did not self-bite. Home-cage behavior did not predict later self-biting, but it did change with increasing age: surrogate clinging and self-mouthing decreased, while environmental exploration increased. Our findings suggest that surrogate rearing in combination with lower levels of social contact during play may be risk factors for the later development of self-biting behavior.     

Self-organization versus Watchmaker: ambiguity of molecular recognition and design charts of cellular circuitry

A large body of experimental evidence indicates that the specific molecular interactions and/or chemical conversions depicted as links in the conventional diagrams of cellular signal transduction and metabolic pathways are inherently probabilistic, ambiguous and context-dependent. Being the inevitable consequence of the dynamic nature of protein structure in solution, the ambiguity of protein-mediated interactions and conversions challenges the conceptual adequacy and practical usefulness of the mechanistic assumptions and inferences embodied in the design charts of cellular circuitry. It is argued that the reconceptualization of molecular recognition and cellular organization within the emerging interpretational framework of self-organization, which is expanded here to include such concepts as bounded stochasticity, evolutionary memory, and adaptive plasticity offers a significantly more adequate representation of experimental reality than conventional mechanistic conceptions do. Importantly, the expanded framework of self-organization appears to be universal and scale-invariant, providing conceptual continuity across multiple scales of biological organization, from molecules to societies. This new conceptualization of biological phenomena suggests that such attributes of intelligence as adaptive plasticity, decision-making, and memory are enforced by evolution at different scales of biological organization and may represent inherent properties of living matter.