Advancing breeding phenology in response to environmental change in a wild red deer population

Most evidence for advances in phenology of in response to recent climate warming in wild vertebrate populations has come from long‐term studies of birds. Few studies have either documented phenological advances or tested their climatic causes and demographic consequences in wild mammal systems. Using a long‐term study of red deer on the Isle of Rum, Scotland, we present evidence of significant temporal trends in six phenological traits: oestrus date and parturition date in females, and antler cast date, antler clean date, rut start date and rut end date in males. These traits advanced by between 5 and 12 days across a 28‐year study period. Local climate measures associated with plant growth in spring and summer (growing degree days) increased significantly over time and explained a significant amount of variation in all six phenological traits, largely accounting for temporal advances observed in some of the traits. However, there was no evidence for temporal changes in key female reproductive performance traits (offspring birth weight and offspring survival) in this population, despite significant relationships between these traits and female phenology. In males, average antler weights increased over time presumably as a result of improved resource availability and physiological condition through spring and summer. There was no evidence for any temporal change in average male annual breeding success, as might be expected if the timing of male rutting behaviour was failing to track advances in the timing of oestrus in females. Our results provide rare evidence linking phenological advances to climate warming in a wild mammal and highlight the potential complexity of relationships between climate warming, phenology and demography in wild vertebrates.     

The Damaging Effect of Water on Dry Pea Embryos During Imbibition

When pea seeds were imbibed in water without their seed coats,vital staining revealed that cells on the abaxial surface ofthe cotyledons were dead. No damage occurred on the surfaceof cotyledons when the seeds were imbibed intact, or beneaththe testa when only half of the testa was removed. Cell deathoccurred as a result of rapid water uptake within the first2 min of imbibition, since reducing the rate of imbibition insolutions of Carbowax 4000 lessened the damage. Cell death wasrestricted to the outer layers of the cotyledons; inner tissuesremained alive. These observations supported the hypothesisthat rapid early leakage during imbibition of dry embryos resultedfrom the death of cells caused by the physical disruption ofmembranes. Imbibition damage resulted in reduced respirationand germination, a decline in the rate of food reserve transferfrom the cotyledons to the growing axis, and a lower growthrate in the seedlings produced. Greater sensitivity of embryosto imbibition damage at low temperature, and similarities betweenfeatures of imbibition damage and chilling injury led to thesuggestion that so-called chilling injury is the result of imbibitiondamage rather than the effects of low temperature.     

Plant and insect genetic variation mediate the impact of arbuscular mycorrhizal fungi on a natural plant–herbivore interaction

1. While both arbuscular mycorrhizal (AM) fungi and plant and insect genotype are well known to influence plant and herbivore growth and performance, information is lacking on how these factors jointly influence the relationship between plants and their natural herbivores. 2. The aim of the present study was to investigate how a natural community of arbuscular mycorrhizal fungi affects the growth of the perennial herb Plantago lanceolata L. (Plantaginaceae), as well as its interaction with the Glanville fritillary butterfly [Melitaea cinxia L. (Nymphalidae)]. For this, a multifactorial experiment was conducted using plant lines originating from multiple plant populations in the Åland Islands, Finland, grown either with or without mycorrhizal fungi. For a subset of plant lines, the impact of mycorrhizal inoculation, plant line, and larval family on the performance of M. cinxia larvae were tested. 3. Arbuscular mycorrhizal inoculation did not have a consistently positive or negative impact on plant growth or herbivore performance. Instead, plant genetic variation mediated the impact of arbuscular mycorrhizal fungi on plant growth, and both plant genetic variation and herbivore genetic variation mediated the response of the herbivore. For both the plant and insect, the impact of the arbuscular mycorrhizal community ranged from mutualistic to antagonistic. Overall, the present findings illustrate that genetic variation in response to mycorrhizal fungi may play a key role in the ecology and evolution of plant–insect interactions.     

The effect of inoculating flowers and developing fruits with Botrytis cinerea on post-harvest grey mould of red raspberry

Raspberry flowers were inoculated in the glasshouse and field with dry conidia of Botrytis cinerea and the fruits derived from them subjected to post-harvest rot tests at c. 20°C and high humidity. Apparently healthy fully-ripe picked fruits derived from inoculated flowers developed grey mould faster than those from non-inoculated flowers in all tests. In the glasshouse experiments, fruits from inoculated tightly closed flower buds rotted more slowly than those from inoculated open flowers or those at later developmental stages. Fruits from inoculated whole flowers rotted more rapidly than those from emasculated flowers; the addition of pollen to emasculated flowers had little effect on post-harvest grey mould. In the dry summer of 1984 no fruits in the field from inoculated whole flowers rotted before ripening, but in the wet season of 1985 pre-harvest grey mould was common and the surviving healthy fruits rotted in c. 1 day after picking. Only minor differences were detected in host susceptibility to post-harvest grey mould in both glasshouse and field tests, the ranking of genotypes varied depending on whether or not flowers had been inoculated. The susceptibility of pistils of 40 Rubus genotypes to infection was examined 7 and 28 days after inoculation of stigmas with dry conidia. Conidia germinated on the stigmas and produced hyphae which grew through transmitting tissues of the styles to infect carpels symptomlessly in 17 red raspberries, one blackberry, two Rubus spp. and one hybrid. No germination occurred on stigmas of cv. Carnival and New York Selection 817.     

Exploring the consequences of climate‐induced changes in cloud cover on offspring of a cool‐temperate viviparous lizard

Historically, studies on the response of ectotherms to anthropogenic climate change have emphasized predicted changes in temperature, with few examining responses associated with additional climatic changes. Basking behaviour is an absolute requirement for lizards from temperate regions because elevated body temperatures are needed for processes such as digestion and embryogenesis. Given that predicted cloud‐cover changes will alter basking opportunities in many locations, we measured the phenotypic consequences of an increase or reduction in basking opportunity during pregnancy on the offspring of a viviparous temperate skink. The sex, size, growth, survival, emergence behaviour, morphotype, pigmentation, and locomotor performance of offspring were measured up to 3 months of age. Most offspring characteristics (e.g. sex) were not influenced by maternal basking regime. However, maternal pregnancy success was lower, and female offspring were slower growing, and thus smaller, when from regimes mimicking high cloud cover, suggesting potential long‐term influences on population dynamics. Although a link between basking regime and phenotype has been reported in viviparous lizards, this is the first study to explore possible negative implications of changes in cloud cover on offspring production and phenotype (other than sex). © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 844–851.     

Early fish growth varies in response to components of the flow regime in a temperate floodplain river

1. The biological productivity of floodplain rivers is intimately related to their flow regimes and it has been proposed that fish production should be linked to components of the flow regime in productivity models. To assess applicability of existing models of productivity in floodplain rivers, we tested predictions about growth during the early life stages of a common, short‐lived fish (Australian smelt Retropinna semoni) in a non‐flow‐altered, temperate Australian floodplain river. 2. The morphometric condition of larval and juvenile fish measured over a five‐year period was positively related to annual discharge, but the highest average seasonal growth rates occurred in two years of contrasting hydrology, one with early spring flooding and the other with predominantly low flows and a late season (within channel) flow pulse. 3. Analysis of daily growth measures indicated that timing, river height, the duration of in‐channel flow events and antecedent flood events are all significant factors influencing the early growth of Australian smelt. The flexible manner in which fish growth responds to these factors appears to be an effective early life history strategy for a short‐lived species occupying a highly variable environment. 4. Growth rates conformed to some predictions of the Flood Pulse Concept (in particular the Extended Flood Pulse Concept), but specific growth responses suggest that the Riverine Productivity Model and tenets of the Low Flow Recruitment Hypothesis best describe the production of Australian smelt in this system. We suggest that none of the existing conceptual models adequately describes fish productivity in temperate Australian floodplain rivers but that aspects of each are likely to be relevant under different flow conditions.     

Nitrogen oxide gas emissions from temperate forest soils receiving long-term nitrogen inputs

From spring 2000 through fall 2001, we measured nitric oxide (NO) and nitrous oxide (N₂O) fluxes in two temperate forest sites in Massachusetts, USA that have been treated since 1988 with different levels of nitrogen (N) to simulate elevated rates of atmospheric N deposition. Plots within a pine stand that were treated with either 50 or 150 kg N ha^?1 yr^?1 above background displayed consistently elevated NO fluxes (100–200 µg N m^?2 h^?1) compared to control plots, while only the higher N treatment plot within a mixed hardwood stand displayed similarly elevated NO fluxes. Annual NO emissions estimated from monthly sampling accounted for 3.0–3.7% of N inputs to the high‐N plots and 8.3% of inputs to the Pine low‐N plot. Nitrous oxide fluxes in the N‐treated plots were generally < 10% of NO fluxes. Net nitrification rates (NRs) and NO production rates measured in the laboratory displayed patterns that were consistent with field NO fluxes. Total N oxide gas flux was positively correlated with contemporaneous measurements of NR and concentration. Acetylene inhibited both nitrification and NO production, indicating that autotrophic nitrification was responsible for the elevated NO production. Soil pH was negatively correlated with N deposition rate. Low levels (3–11 µg N kg^?1) of nitrite () were detected in mineral soils from both sites. Kinetic models describing NO production as a function of the protonated form of (nitrous acid [HNO₂]) adequately described the mineral soil data. The results indicate that atmospheric deposition may generate losses of gaseous NO from forest soils by promoting nitrification, and that the response may vary significantly between forest types under similar climatic regimes. The lowering of pH resulting from nitrification and/or directly from deposition may also play a role by promoting reactions involving HNO₂.     

The questionable affinities of Corsia (Corsiaceae): evidence from floral anatomy and pollen morphology

The floral anatomy and pollen morphology of Corsia are described in the context of its systematic relationships. Flowers of Corsia are epigynous, lack septal nectaries and possess a large labellum formed from the outer median tepal (sepal). The labellum is highly vascularized and has a prominent outgrowth (callus) that is apparently nectiiferous in some species of section Sessilis , although not in section Unguiculatis . The six fertile stamens are proximally fused to the style, forming a gynostemium. This combination of labellum and gynostemium is otherwise found only in Orchidaceae (Asparagales), but the orchid labellum is formed from the opposite median inner tepal, and is therefore not homologous with that of Corsia . The three genera of Corsiaceae ( Corsia , Arachnitis and Corsiopsis ) are markedly different in some respects; e.g. only Corsia has a gynostemium. However, they share a unique synapomorphy in the presence of a labellum formed from the outer median tepal (sepal). Corsia and Arachnitis are also similar in pollen sexine sculpturing. Among other putative relatives, the range of morphological similarities between Corsia and Campynemataceae (Liliales) tends to support recent preliminary inferences from molecular data that they are closely related, but a relationship with Thismia (Dioscoreales) cannot be discounted. Both Campynemataceae and Thismia share similarities with Corsia , including epigyny, absence of septal nectaries, presence of tepal nectaries, and pollen morphology. © 2002 Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 315–324.     

A new species of the catfish Nigerium from the Palaeogene of the Tilemsi Valley,Republic of Mali

Abstract: The phosphate deposits of the Tilemsi Valley, Republic of Mali, West Africa, are well known for their rich fossil vertebrate fauna including fishes, crocodilians, snakes and mammals. Despite this, the exact age of the deposits has been in some doubt. Here, a new species of catfish, Nigerium tamaguelense sp. nov., is described from the phosphate deposits at Tamaguélelt, Tilemsi Valley, based on a large collection of 29 well‐preserved crania. The crania are compared with the known species of Nigerium, N. wurnoense White and N. gadense White. The genus Nigerium is reviewed and now placed in the family Claroteidae based on a combination of three derived characters. Nigerium is compared with other African fossil catfish genera and the fossil record of catfish families in Africa is reviewed. The new evidence presented here shows the Claroteidae to be the earliest occurring catfish family in Africa. Evidence is also presented for an Early Eocene age for the phosphate deposits at Tamaguélelt.     

Agouti Protein Inhibits the Production of Eumelanin and Phaeomelanin in the Presence and Absence of α-Melanocyte Stimulating Hormone

Melanocytes synthesise two types of melanin: the brown-black eumelanin and the red-yellow phaeomelanin. In mice, the relative proportions of these two melanins are regulated by α-MSH, which preferentially increases the synthesis of eumelanin and by the Agouti protein (AP), the expression of which correlates with the growth of yellow phaeomelanin-containing hair. It has been proposed that AP acts by antagonizing the action of α-MSH at the MCI receptor, although it has been suggested that it may also act independently of α-MSH. In the present study we show that AP inhibits melanogenesis in B16F1 melanoma cells in the presence and absence of α-MSH and also causes dose-related decreases in the synthesis of both eumelanin and phaeomelanin. In the presence of α-MSH AP had a greater effect on eumelanin production and this is consistent with an antagonistic action at the MCI receptor. In the absence of α-MSH however, AP produced similar reductions in the synthesis of both melanins. These changes were not seen in B16G4F cells which lack the MCI receptor, suggesting that even in the absence of α-MSH AP acts at the MCI receptor. How this action is mediated at the intracellular level is not yet clear, although it appears to be associated with a decrease in tyrosinase activity.