Newly developed polymorphic microsatellite markers in Job's tears (Coix lacryma‐jobi L.)

A microsatellite‐enriched library of Job's tears (Coix lacryma‐jobi L. var. Ma‐yuen Stapf) was constructed using a modified biotin–streptavidin capture method. After screening, 17 polymorphic microsatellites were used for diversity analysis among 30 Job's tears accessions. The number of alleles ranged from one to five alleles per locus with an average of 2.8 alleles. Expected heterozygosity (H_E) and polymorphism information content (PIC) ranged from 0 to 0.676 and from 0 to 0.666, respectively. The newly developed microsatellite markers are expected to be very valuable tools for evaluation of genetic diversity among large germplasm collection of Job's tears present in our Korean Gene Bank.     

Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance

Estimates of carbon leaching losses from different land use systems are few and their contribution to the net ecosystem carbon balance is uncertain. We investigated leaching of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and dissolved methane (CH₄), at forests, grasslands, and croplands across Europe. Biogenic contributions to DIC were estimated by means of its δ¹³C signature. Leaching of biogenic DIC was 8.3±4.9 g m^?2 yr^?1 for forests, 24.1±7.2 g m^?2 yr^?1 for grasslands, and 14.6±4.8 g m^?2 yr^?1 for croplands. DOC leaching equalled 3.5±1.3 g m^?2 yr^?1 for forests, 5.3±2.0 g m^?2 yr^?1 for grasslands, and 4.1±1.3 g m^?2 yr^?1 for croplands. The average flux of total biogenic carbon across land use systems was 19.4±4.0 g C m^?2 yr^?1. Production of DOC in topsoils was positively related to their C/N ratio and DOC retention in subsoils was inversely related to the ratio of organic carbon to iron plus aluminium (hydr)oxides. Partial pressures of CO₂ in soil air and soil pH determined DIC concentrations and fluxes, but soil solutions were often supersaturated with DIC relative to soil air CO₂. Leaching losses of biogenic carbon (DOC plus biogenic DIC) from grasslands equalled 5–98% (median: 22%) of net ecosystem exchange (NEE) plus carbon inputs with fertilization minus carbon removal with harvest. Carbon leaching increased the net losses from cropland soils by 24–105% (median: 25%). For the majority of forest sites, leaching hardly affected actual net ecosystem carbon balances because of the small solubility of CO₂ in acidic forest soil solutions and large NEE. Leaching of CH₄ proved to be insignificant compared with other fluxes of carbon. Overall, our results show that leaching losses are particularly important for the carbon balance of agricultural systems.     

Information parasitism in foraging Bar-tailed Godwits Limosa lapponica

Foraging behaviour of sympatric Bar-tailed Godwits Limosa lapponica and Whimbrels Numenius phaeopus was studied in the period prior to egg-laying. Godwit females preferred wet bogs, while godwit males and Whimbrels foraged on dry palsas in the bogs. Habitat overlap between godwit males and Whimbrels was larger than intersexual overlap in the godwits. Observations of scanning behaviour of foraging godwits showed that the vigilance level of males was not affected by the presence or absence of their mates. Female vigilance levels, however, dropped significantly when females fed near their mate, and—in the absence of the mate—near Whimbrels. While female godwits benefited from associating with Whimbrels, males seemed to avoid close proximity to this species. Whimbrels chased godwit males more often than females, presumably because they used the same foraging habitats.     

Changes in sperm stores, ejaculate size, fertilization success, and sexual motivation over repeated matings in the common toad, Bufo bufo (Anura: Bufonidae)

Fertilization is of central importance in the determination of reproductive success for both males and females. In species where males have the chance to mate repeatedly within a short period of time, sperm stocks may become depleted and males may have to carefully economize on their sperm reserves. Also, intensive intrasexual competition for females and repeated matings may lead to exhaustion on the behavioural level. To determine whether the reproductive potential of males is limited and if such a limitation is due to behavioural exhaustion or sperm depletion, we experimentally investigated changes in sperm stores, sperm expenditure, fertilization success, and sexual motivation over three repeated matings in the common toad, Bufo bufo , where the breeding season is short and sequential polygyny occurs. At the end of the breeding season, the number of sperm stored in the testes of males mated repeatedly was close to 50% lower than in testes of unmated males. Ejaculate size, which was estimated by applying a novel method allowing direct quantification, decreased by 88% from first to third matings. We also observed a drop in fertilization success from the first two to third matings by 65%, which was largest in males that had started the reproductive season in bad body condition. Some of these males also showed a decreased interest in females in the third mating round. Our results suggest that sperm depletion and loss of sexual motivation may together set a limit to the reproductive potential of common toad males. The present study draws attention to a limitation in reproductive potential, which may occur more often than currently anticipated and has the potential to strongly influence several aspects of reproductive behaviour.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 361–371.     

Contrasting levels of genetic diversity between the historically rare orchid Cypripedium japonicum and the historically common orchid Cypripedium macranthos in South Korea

Many terrestrial orchids are historically rare and occur in small, spatially isolated populations. Theory predicts that such species will harbour low levels of genetic variation within populations and will exhibit a high degree of population genetic divergence, primarily as a result of genetic drift. If the origin of the present‐day populations is relatively recent from the same genetically depauperate source population, a complete lack of genetic differentiation between conspecific populations is expected. If a terrestrial orchid was historically common with moderate or high levels of genetic diversity, but has experienced more recent anthropogenic disturbance as a result of over‐collection, it would still exhibit initial levels of genetic variation within populations and a low degree of genetic divergence between populations. To test these predictions, we examined the genetic diversity in six populations (N = 131) of the historically and currently rare Cypripedium japonicum and in four populations (N = 94) of the historically common but now rare C. macranthos from South Korea. Fourteen putative allozyme loci resolved from eight enzyme systems revealed no variation either within or among populations of C. japonicum, which supports the first prediction. In contrast, populations of C. macranthos harboured high levels of genetic variation (mean percentage of polymorphic loci %P = 46.7; mean expected heterozygosity H_e = 0.185) and exhibited a low degree of population genetic divergence (G_ST = 0.059), supporting the second prediction. The lack of genetic variation both within and among conspecific populations of C. japonicum may suggest that populations originated from the same genetically depauperate ancestral population. The high levels of genetic diversity maintained in populations of C. macranthos suggest that the collection‐mediated decrease in the number of individuals is still too recent for long‐term effects on genetic variation. Based on current demographic and genetic data, in situ and ex situ conservation strategies should be provided to preserve genetic variation and to ensure the long‐term survival of the two species in the Korean Peninsula. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 160 , 119–129.     

Gustatory mechanisms and sugar-feeding in the mosquito, Culiseta inornata

ABSTRACT. Gustatory hairs on the legs and mouthparts of the mosquito, Culiseta inornata , were stimulated with sucrose solutions to determine their role in the finding and consuming of nectar by females. Stimulation of tarsi initiated probing, which continued without subsequent stimulation of tarsal hairs. Turning in response to tarsal stimulation depended on which leg was stimulated. Once gustatory hairs on the labella were stimulated, turning and probing were discontinued. Stimulation of the hairs on the external surface of the labella apparently initiates the labellar opening response, while stimulation of hairs on the oral surface of the labella maintains the labellar response. Electrophysiologically recorded activity of cibarial and pharyngeal pumps was used to assess the influence of the five relevant sets of gustatory hairs on initiation of sucking. None of the sets alone were capable of initiating sucking. Sucking was initiated when the hairs on the oral surface of the labella were stimulated simultaneously with sensory hairs on the tip of the labrum. The gustatory hairs on the oral surface of the labella exerted considerable influence in determining the amount of sugar or water imbibed.     

Implications of Woodrats and Other Scavengers for Avian Telemetry Studies

Abstract: During 2 years of radiotelemetry research on chukars (Alectoris chukar) in western Utah, USA, we found 28% of retrieved radios (n = 78) in rubbish nests of woodrats (Neotoma spp.). Such movement and disturbance of carcasses and radios by woodrats and other species has implications for radiotelemetry studies. We evaluated spatio-temporal movement of 51 radiocollars attached to chukar carcasses in western Utah. Most (80%) carcasses were scavenged within one week and by the end of 3 weeks 25 (50%) had been retrieved from woodrat middens. Scavenging activity can both obscure important clues needed to identify causes of mortality and bias telemetry studies by delaying onset of mortality signals.     

Speciation problems in the Papilio machaon group of butterflies (Lepidoptera: Papilionidae)

Abstract. The taxonomic and genetic relationships between P.machaon rathjensi Warnecke from the west side of southern Arabia and P.machaon muetingi Seyer from the east are discussed, together with suggestions of their relationship to P.machaon saharae Oberthiir from the northern Hejaz, Sinai and desert North Africa. It is concluded that though P.m.rathjensi and P.m.saharae are subspecifically distinct, they are very closely related to each other, and both should be regarded as specifically distinct from the rest of the machaon complex.
The remainder of the machaon complex in its turn presents a somewhat similar problem. Thus P.machaon gorganus Fruhstorfer and P.hospiton Géné are normally regarded as good species, but Fl caterpillars have been found in the wild and the cross can be readily produced in captivity with no upset in the sex ratio. Furthermore, recently we have obtained sparse F2 offspring between the two species.
We therefore suggest that the entire P.machaon complex is in a labile state as regards speciation throughout its range and the relationships between the various forms are not easily expressed through the traditional species and subspecies concepts. Our tentative conclusions are that the status of P.machaon and P.hospiton as distinct species probably remains valid. The saharaelrathjensi complex might be considered distinct from P.machaon using the biological species concept, while their genetics indicate a more conservative approach. However, more important than the exact status of the taxa in question is the fact that the P.machaon complex illustrates evoluton in action, the end result of which cannot be predicted.