Development of <Emphasis Type="Italic">Cleruchoides noackae</Emphasis>, an egg-parasitoid of <Emphasis Type="Italic">Thaumastocoris peregrinus</Emphasis>, in eggs laid on different substrates,with different ages and post-cold storage

Cleruchoides noackae Lin and Huber (Hymenoptera: Mymaridae) is an egg parasitoid of Thaumastocoris peregrinus Carpintero and Dellapé (Hemiptera: Thaumastocoridae). The parasitism and development of C. noackae was studied in T. peregrinus eggs of different ages, laid on eucalyptus leaves or paper towel and stored at 5 °C. The emergence, sex ratio and development of C. noackae and hatched nymphs of T. peregrinus were evaluated. This parasitoid had an emergence rate higher than 60% from zero to one, one to two, and two to three-day old eggs and lower than 10% for those 3–4 and 4–5 days old. The female proportion was 78% and the egg-adult period for C. noackae was 19.5 days. The use of T. peregrinus eggs up to three days old, laid on paper towel and stored at 5 °C for 14 days did not affect the biological parameters of C. nockae and should be used for mass rearing of this parasitoid.     

Biological Data on <Emphasis Type="Italic">Anovia punica</Emphasis> Gordon (Coleoptera: Coccinellidae), a Predator of <Emphasis Type="Italic">Crypticerya multicicatrices</Emphasis> Kondo &amp; Unruh (Hemiptera: Monophlebidae)

The coccinellid beetle Anovia punica Gordon (Coleoptera: Coccinellidae: Noviini) is an important predator of the Colombian fluted scale, Crypticerya multicicatrices Kondo & Unruh (Hemiptera: Monophlebidae). In order to gather information on the biological traits of A. punica, we conducted a series of studies, including of the developmental time of each life history stage, estimation of life table parameters, and predation rates under laboratory conditions [25.1 ± 1.6°C, with 70.5 ± 7.3% RH, and natural light regime, approx. 12:12 (L:D) h]. Developmental stages of A. punica were categorized as follows: egg stage, four larval instars, prepupal instar, pupal instar, and adult. Developmental time from egg to adult emergence averaged 29.41 ± 1.85 days, and 47.6% of the eggs developed to adulthood. Female and male survival was 94.42 and 90 days, respectively. Life table parameters show that one female of A. punica is replaced by 86 females (R ₀), the intrinsic growth rate (r _m ) was 0.1115, the average generation time (T) was 40 days, and the doubling time (D _t ) was 6.2 days. The life table parameters suggest that A. punica can be used as a potential predator of C. multicicatrices and, more importantly, provided baseline information for a mass-rearing protocol. This is the first detailed study on the biology of A. punica that reports the potential of this predator as a biological control agent for scale insects of the tribe Iceryini.     

Maternal care,larviparous and oviparous reproduction of <Emphasis Type="Italic">Hypoaspis larvicolus</Emphasis> (Acari: Laelapidae) feeding on astigmatid mites

Hypoaspis larvicolus (Acari: Laelapidae) (first report from Turkey) occurred together with Sancassania polyphyllae (Acari: Acaridae) on the larvae of the scarab beetle, Polyphylla fullo (Coleoptera: Scarabaeidae), that were feeding on the roots of strawberry in Aydin, Turkey. Laboratory studies were conducted to (1) observe whether H. larvicolus feeds and completes its life cycle on the various stages of S. polyphyllae or other astigmatid mites, such as Acarus siro, Carpoglyphus lactis and Tyrophagus putrescentiae (Acaridae), and to determine its population growth when feeding on these prey, and (2) to determine development periods, longevity and fecundity of H. larvicolus feeding on C. lactis. Hypoaspis larvicolus females did not feed on S. polyphyllae, but fed, developed and reproduced when A. siro, C. lactis or T. putrescentiae were provided as prey. Hypoaspis larvicolus is larviparous as well as oviparous. The female lays eggs or gives birth to larvae. If a female gives birth to a larva, it is attached under the female’s venter for 1–2 days, a phenomenon recorded for the first time in Hypoaspis; in fact, for the first time in mites. The results of the population growth experiments revealed that H. larvicolus feeding on C. lactis produced the highest number of eggs, juveniles and adults. The developmental periods of H. larvicolus feeding on C. lactis at life-cycle path I (larva to adult) and II (egg to adult) were 12.2?±?0.3 and 15.6?±?0.6 days (females) and 19.5?±?0.2 and 20.9?±?0.4 days (males), respectively. Longevity of females versus males of H. larvicolus was 120.6?±?7.2 versus 91.6?±?13.1 days (life cycle I) and 110.0?±?27.7 versus 118.3?±?10.9 days (life cycle II), respectively.     

A review of the history of research and control of <Emphasis Type="Italic">Rhipicephalus</Emphasis> (<Emphasis Type="Italic">Boophilus</Emphasis>) <Emphasis Type="Italic">microplus</Emphasis>, babesiosis and anaplasmosis in Uruguay

The effect of five constant temperatures (16, 20, 24, 28 and 32 °C) on the development, survival and reproduction of Tetranychus cinnabarinus (Boisduval) [=?Tetranychus urticae Koch (red form)] fed on cassava leaves was examined in the laboratory at 85% relative humidity. Development time of various immature stages decreased with increasing temperature, with total egg-to-adult development time varying from 27.7 to 6.7 days. The lower thermal threshold for development was 10.8 °C and the thermal constant from egg to adult was 142.4 degree-days. Pre- and post-oviposition period and female longevity all decreased as temperature increased. The longest oviposition period was observed at 20 °C with 20.4 days. Under different temperatures, mated females laid, on average, 1.0, 2.9, 4.7, 4.7 and 4.9 eggs per day, respectively. The maximum fecundity (81.5 eggs per female) was at 28 °C and the intrinsic rate of increase (r _m ) was highest (0.25) at 32 °C. The results of this study indicate that T. cinnabarinus population could increase rapidly when cassava leaves serve as a food source. At the appropriate temperature T. cinnabarinus could seriously threaten growth of cassava.     

A novel thermostable and organic solvent-tolerant lipase from <Emphasis Type="Italic">Xanthomonas oryzae</Emphasis> pv. <Emphasis Type="Italic">oryzae</Emphasis> YB103: screening,purification and characterization

Thermostable lipases offer major biotechnological advantages over mesophilic lipases. In this study, an intracellular thermostable and organic solvent-tolerant lipase-producing strain YB103 was isolated from soil samples and identified taxonomically as Xanthomonas oryzae pv. oryzae. The lipase from X. oryzae pv. oryzae YB103 (LipXO) was purified 101.1-fold to homogeneity with a specific activity of 373.9 U/mg. The purified lipase showed excellent thermostability, exhibiting 51.1 % of its residual activity after incubation for 3 days at 70 °C. The enzyme showed optimal activity at 70 °C, suggesting it is a thermostable lipase. LipXO retained 75.1–154.1 % of its original activity after incubation in 20 % (v/v) hydrophobic organic solvents at 70 °C for 24 h. Furthermore, LipXO displayed excellent stereoselectivity (e.e._p >99 %) toward (S)-1-phenethyl alcohol in n-hexane. These unique properties of LipXO make it promising as a biocatalyst for industrial processes.     

Expression of ethylene biosynthetic and signaling genes in relation to ripening of banana fruit after cold storage

Banana fruit are highly sensitive to chilling injury (CI), while the effect of different degrees of CI on the subsequent fruit ripening is largely unknown. In the present work, ripening characteristic of banana fruit after storage at 7 °C for 3 days or for 8 days, and expression levels of eight genes associated with ethylene biosynthetic and signaling, including MaACS1, MaACO1, MaERS1, MaERS3, and MaEIL1–4, were investigated. The results showed that banana fruit stored at 7 °C for 8 days exhibited more severe chilling symptoms than those at 7 °C for 3 days. Compared with banana fruit stored at 7 °C for 8 days, which showed abnormal ripening, more decrease in fruit firmness, while higher increase in ethylene production and hue angle were observed in banana fruit stored at 7 °C for 3 days, which could ripening normally. Moreover, gene expression profiles during ripening revealed that ethylene biosynthetic and signaling genes were differentially expressed in peel and pulp of banana fruit after storage at 7 °C for 3 days and 7 °C for 8 days. In the peel of fruit storage at 7 °C for 3 days, expression levels of MaACS1, MaACO1, MaEIL1, and MaEIL2 increased remarkably while MaERS3, MaEIL1, and MaEIL4 were enhanced in the fruit after storage at 7 °C for 8 days. In the pulp, with the exception of MaACO1 and MaERS3, expression levels of other genes did not exhibit a significant difference, between the banana fruit storage at 7 °C for 3 days and 7 °C for 8 days. Taken together, our results suggest that differential expression of ethylene biosynthetic and signaling genes such as MaERS3, MaACO1, and MaEIL2, may be related to ripening behavior of banana fruit with different degrees of CI after cold storage.     

Changes in Body Wall of Sea Cucumber (<Emphasis Type="Italic">Stichopus japonicus</Emphasis>) during a two-Step Heating Process Assessed by Rheology,LF-NMR,and Texture Profile Analysis

Sea cucumber (Stichopus japonicus) is regarded as a highly priced delicacy in Japan and China owing to its unique elasticity and palatability. Heating is an essential step to process sea cucumber with desired texture. In the present study, sea cucumber body wall was pre-heated at 40 °C, followed by post-heating at 80 °C. Changes in body wall were assessed by rheology, LF-NMR, and texture profile analysis. The small strain rheological analysis indicated that there were significant structural changes of body wall at about 40 °C during pre-heating. Large strain texture profile analysis and the storage modulus showed a good correlation. LF-NMR analysis displayed only one water population in samples pre-heated at 40 °C for up to 120 min, and the population did not change significantly with the heating duration. This demonstrated that structural changes and moisture loss from the inter collagen fibrils were not significant. As for samples post-heated at 80 °C, three distinct peaks were found and the T ₂ relaxation time and area of the bulk water decreased significantly, revealing significant changes of internal structures and loss of water-holding capacity. T ₂ parameters had a good correlation to texture profile analysis parameters for samples after both pre-heating and post-heating.     

Cold tolerance and invasive potential of the redbay ambrosia beetle (<Emphasis Type="Italic">Xyleborus glabratus</Emphasis>) in the eastern United States

Native Lauraceae (e.g. sassafras, redbay) in the southeastern USA are being severely impacted by laurel wilt disease, which is caused by the pathogen Raffaelea lauricola T. C. Harr., Fraedrich and Aghayeva, and its symbiotic vector, the redbay ambrosia beetle (Xyleborus glabratus Eichhoff). Cold temperatures are currently the only viable limitation to the establishment of X. glabratus in northern populations of sassafras. The observed lower lethal temperature of X. glabratus (? 10.0 °C) is warmer than its supercooling point (? 22.0 °C), indicating the beetle is a freeze intolerant and chill susceptible species. Empirically derived X. glabratus lower lethal temperature thresholds were combined with host distribution and microhabitat-corrected climate data to produce species distribution models for X. glabratus in the eastern USA. Macroclimate data (30-year mean annual minimum temperature) were corrected (? 1.2 °C) to account for thermal buffering afforded to X. glabratus while living inside sassafras trees. Only 0.1% of the current US sassafras spatial extent experiences sufficiently harsh winters (locales where mean annual minimum winter temperatures ≤ ? 6.2 °C for ≥ 12 h) to exclude X. glabratus establishment in our species distribution model. Minimum winter temperatures will likely cause some X. glabratus mortality in ~ 52% of the current spatial extent of sassafras, although current data do not allow a quantification of X. glabratus mortality in this zone. Conversely, ~ 48% of the current spatial extent of sassafras is unlikely to experience sufficiently cold winter temperatures to cause any significant impediment to X. glabratus spread or establishment. A modest climate change scenario (RCP4.5) of + 1.4 °C would result in 91% of the current spatial extent of sassafras in the eastern USA occurring where winter minimum temperatures are unlikely to cause any mortality to X. glabratus.     

Fertility Life Table of <Emphasis Type="Italic">Tetranychus palmarum</Emphasis> Flechtmann &amp; Noronha (Acari: Tetranychidae) in Oil Palm

Some species of spider mites belonging to the Tetranychidae family are known to associate with oil palm (Elaeis guineensis Jacq. – Arecaceae). The occurrence of Tetranychus palmarum Flechtmann & Noronha (Acari, Tetranychidae) was verified on oil palm seedlings under greenhouse conditions in the State of Pará in Northern Brazil. Plants with colonies of T. palmarum presented yellowish spots on leaflets and leaves with chlorosis. The objective of this study was to access the biology and fertility life table of T. palmarum in E. guineensis leaves. The experiment was conducted under four constant temperatures, 22, 25, 28, and 31°C, at 70 ± 10% RH under a 12:12 LD photoperiod. The duration of the egg-to-adult period was 18.4 and 9.8 days, at 22 and 31°C, respectively. The parameters of the fertility life table showed that 28°C is most suitable for the development and reproduction of T. palmarum, with higher values for reproductive parameters (R _o , r _m , and λ) and lower values for duplicating the population (TD). Therefore, it is apparent that the best temperature conditions for the development of T. palmarum are found in the warmer regions of Brazil, such as those observed in northern Brazil.     

High-yield expression,purification, characterization,and structure determination of tag-free <Emphasis Type="Italic">Candida utilis</Emphasis> uricase

We report the successful high-yield expression of Candida utilis uricase in Escherichia coli and the establishment of an efficient three-step protein purification protocol. The purity of the recombinant protein, which was confirmed to be C. utilis uricase by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometer analysis, was >98% and the specific activity was 38.4 IU/mg. Crystals of C. utilis uricase were grown at 18°C using 25% polyethylene glycol 3350 as precipitant. Diffraction by the crystals extends to 1.93 Å resolution, and the crystals belong to the space group P2₁2₁2₁ with unit cell parameters a?=?69.16 Å, b?=?139.31 Å, c?=?256.33 Å, and α?=?β?=?γ?=?90°. The crystal structure of C. utilis uricase shares a high similarity with other reported structures of the homologous uricases from other species in protein database, demonstrating that the three-dimensional structure of the protein defines critically to the catalytic activities.     

Effect of Temperature on Development and Reproduction of <Emphasis Type="Italic">Epilachna dodecastigma</Emphasis> (Wied.) (Coleoptera: Coccinellidae)

The effect of five constant temperatures of 21, 24, 27, 30 and 33 °C on adult life span, reproduction, oviposition behavior and larval developmental time of a bitter gourd inhabited coleopteran insect Epilachna dodecastigma (Wied.) (Coccinellidae) was determined in laboratory conditions under 70 ± 5 % relative humidity and a photoperiod of 12 L : 12 D. Larval developmental time of E. dodecastigma decreased as temperature increased from 21 to 33 °C. Life table data revealed that overall mortality was lowest at 27 °C and highest at 21 °C. Females lived longer than males at all temperatures; but longevity decreased with increase in temperature. Pre-oviposition period decreased significantly with increase in temperature up to 27 °C and thereafter increased at a slower rate; whereas oviposition period decreased significantly with increase in temperature. Fecundity and egg viability increased significantly with an increase in temperature up to 27 °C and thereafter decreased at a slower rate. The intrinsic rate of increase (r _m ) was 0.1703, 0.1984, 0.2235, 0.2227 and 0.2181 day^?1 at 21, 24, 27, 30 and 33 °C, respectively. The net reproductive rate and finite rate of increase was highest at 27 °C (R _o  = 112.05; λ = 1.4233) and lowest at 21 °C (R _o  = 51.23; λ = 1.2581).     

Biology and Thermal Requirements of <Emphasis Type="Italic">Fopius arisanus</Emphasis> (Sonan, 1932) (Hymenoptera: Braconidae) Reared on <Emphasis Type="Italic">Ceratitis capitata</Emphasis> Eggs (Wiedemann) (Diptera: Tephritidae)

Fopius arisanus (Sonan) is a solitary parasitoid of eggs and the first instar larvae of Tephritidae. Due to the occurrence of Ceratitis capitata (Wiedemann) in various regions and under several climatic conditions, this study aimed to evaluate the effect of different temperatures on the embryonic development (egg–adult) and determine thermal requirements and the number of annual generations F. arisanus on eggs of C. capitata. In the laboratory, eggs of C. capitata (24 h) were submitted to parasitism of F. arisanus during 6 h. Later, the eggs were placed in plastic containers (50 mL) (50 eggs/container) on a layer of artificial diet and packed in chambers at temperatures 15, 18, 20, 22, 25, 28, 30, and 32 ± 1°C, RH 70 ± 10%, and a photophase of 12 h. The largest number of offspring, emergence rate, and weight of adults of F. arisanus were observed at 25°C. The highest sex ratios (sr > 0.75) were recorded at 15 and 18°C, being statistically higher than the temperatures 20°C (0.65), 22°C (0.64), 25°C (0.65), 28°C (0.49), and 30°C (0.47). At 32°C, there was no embryonic development of F. arisanus. The egg–adult period was inversely proportional to temperature. Based on the development of the biological cycle (egg–adult), the temperature threshold (T _t) was 10.3°C and thermal constant (K) of 488.34 degree-days, being the number of generations/year directly proportional to the temperature increase. The data show the ability of F. arisanus to adapt to different thermal conditions, which is important for biological control programs of C. capitata.     

Compatibility and efficacy of the lady beetle <Emphasis Type="Italic">Thalassa montezumae</Emphasis> and the entomopathogenic fungus <Emphasis Type="Italic">Isaria fumosorosea</Emphasis> for biological control of the green croton scale: laboratory and greenhouse investigations

The lady beetle Thalassa montezumae and the entomopathogenic fungus Isaria fumosorosea (Ifr) were assessed alone and in combination to suppress green croton scale, Phalacrococcus howertoni, populations on croton plants using laboratory bioassays and greenhouse cage studies. The acquisition of Ifr blastospores by beetle larvae (3rd instar) and adults during contamination in well plates was used to simulate exposure to direct spraying and subsequent possible fungal infection was assessed. Spore dispersal by the insects was determined after the blastospore-contaminated T. montezumae life stages roamed on agar plates for 24 h by counting the number of colony-forming units (CFUs) produced in the plates. There were no significant differences in survival times at 14 days post-treatment between beetle larvae and adults exposed to Ifr and those exposed to water only. Mean survival time of larvae exposed to Ifr was 14 days and water 12 days, whereas for adults it was 13 days compared to 13 days, respectively. Plates with Ifr blastospore-contaminated T. montezumae adults roaming on the agar surface displayed significantly more fungal trails as CFUs compared to plates with larvae. In greenhouse cage studies, the mean mortality rates of the scale exposed to beetle larvae, either alone (80.8%) or in combination with Ifr (89.1%), were not significantly different. Scale mortality rates in the fungus-only (60.5%) and beetle larvae-only treatments were statistically similar. The treatment with both biocontrol agents had a significantly higher scale mortality rate compared to the treatment with Ifr only. Therefore, spraying Ifr prior to releasing T. montezumae is an effective and compatible biological control strategy for management of the green croton scale on croton plants.     

Using hydrothermal time concept to describe sesame (<Emphasis Type="Italic">Sesamum indicum</Emphasis> L.) seed germination response to temperature and water potential

To quantify both temperature (T) and water potential (ψ) effects on sesame (Sesamum indicum L.) seed germination (SG) and also to determine the cardinal T _s for this plant, a laboratory experiment was carried out using hydrothermal time model (HTT). For this purpose, four sesame cultivars (‘Asbomahalleh’, ‘Darab’, ‘Dashtestan’ and ‘Yellowhite’) were germinated at seven constant T _s (20, 25, 30, 35, 37, 39 and 43 °C) at each of the following ψ _s (0, ? 0.12, ? 0.24 and ? 0.36 MPa; provided by PEG 8000). Germination rate (GR) and germination percentage (GP) significantly influenced by ψ, T and their interactions in all cultivars (P ≤ 0.01). There was no significant difference, based on the confidence intervals of the model coefficients, between cultivars, so an average of cardinal T _s was 14.7, 35.4 and 47.2 °C for the minimum (T _b), optimum (T _o) and maximum (T _c) T _s, respectively, in the control condition (0 MPa). Hydrotime values in all cultivars decreased when T was increased to T _o and then remained constant at T _s > T _o (15 MPa h^?1). An average value of ψ _b(50) was estimated to be ? 1.23 MPa at T _s ≤ T _o and then increased linearly (0.1041 MPa°Ch^?1, the slope of the relationship between ψ _b(50) and supra-optimal T _s) with T when T _s increased above T _o and finally reached to zero at T _c. The T _b and T _o values were not influenced by ψ, but T _c value decreased (from 47.2 for zero to 43.5 °C for ? 0.36 MPa) at supra-optimal T _s as a result of the effect of ψ on GR. Based on our findings, this model (as a predictive tool) and or the estimated parameter values in this study can easily be used in sesame SG simulation models to quantitatively characterize the physiological status of sesame seed populations at different T _s and ψ _s.     

Thermal factors affecting egg development in the wandering glider dragonfly, <Emphasis Type="Italic">Pantala flavescens</Emphasis> (Odonata: Libellulidae)

The wandering glider dragonfly, Pantala flavescens (Fabricius), arrives in Japan from tropical regions every spring. The offspring colonize areas throughout Japan, with rapid increases in populations in the autumn, but all individuals die in the winter, suggesting low tolerance to low temperatures. However, few quantitative data on egg development and water temperature have been reported for this species. Females at the reproductive stage were collected from fields throughout the flying season and their eggs released using an artificial oviposition technique. Almost all of the eggs were fertilized. Egg size was stable throughout the seasons. Most eggs hatched within a period of 5 days at high water temperatures (35 and 30 °C), which were recorded in the shallow ponds and rice paddy fields from summer to early autumn. However, the egg-stage duration increased with declining water temperature. All eggs in water at 15 °C had failed to hatch by 90 days. The calculated critical temperature of water was determined to be approximately 14.3 °C; the total effective temperature for the egg stage was about 80 degree-days. Thus, low water temperatures in winter may prevent P. flavescens overwintering in Japan.     

Expression and characterization of glutamate decarboxylase from <Emphasis Type="Italic">Lactobacillus brevis</Emphasis> HYE1 isolated from <Emphasis Type="Italic">kimchi</Emphasis>

A putative gene (gadlbhye1) encoding glutamate decarboxylase (GAD) was cloned from Lactobacillus brevis HYE1 isolated from kimchi, a traditional Korean fermented vegetable. The amino acid sequences of GADLbHYE1 showed 48% homology with the GadA family and 99% identity with the GadB family from L. brevis. The cloned GADLbHYE1 was functionally expressed in Escherichia coli using inducible expression vectors. The expressed recombinant GADLbHYE1 was successfully purified by Ni–NTA affinity chromatography, and had a molecular mass of 54 kDa with optimal hydrolysis activity at 55 °C and pH 4.0. Its thermal stability was determined to be higher than that of other GADs from L. brevis, based on its melting temperature (75.18 °C). Kinetic parameters including K_m and V_max values for GADLbHYE1 were 4.99 mmol/L and 0.224 mmol/L/min, respectively. In addition, the production of gamma-aminobutyric acid in E. coli BL21 harboring gadlbhye1/pET28a was increased by adding pyridoxine as a cheaper coenzyme.     

Low Temperature Storage of <Emphasis Type="Italic">Telenomus remus</Emphasis> (Nixon) (Hymenoptera: Platygastridae) and its Factitious Host <Emphasis Type="Italic">Corcyra cephalonica</Emphasis> (Stainton) (Lepidoptera: Pyralidae)

We conducted three bioassays to evaluate the effect of low-temperature storage of eggs (host) and pupae and adults (parasitoid) on the biology and parasitism capacity of the egg parasitoid Telenomus remus (Nixon) (Hymenoptera: Platygastridae). Viable stored Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) eggs were parasitized to the same degree or even higher than fresh eggs when stored until 14 days at 5°C or until 21 days at 10°C. In contrast, the percentage of parasitized sterilized eggs was equal to the control only when stored for 7 and 14 days. Survival of T. remus pupae declined with storage time at both studied temperatures (5 and 10°C). However, after 7 days of storage, survival of pupae was still 86.3 and 64.9% at 10 and 5°C, respectively. The number of adult male survivors remained similar until the fourth storage day at both 5 and 10°C. In contrast, female survival did not differ until day 8 at 10°C or day 6 at 5°C. Parasitism capacity of stored adults was not altered by storage compared with the control. Therefore, we conclude that the maximal storage time at 10°C is 21 days for viable C. cephalonica eggs and 7 days for T. remus pupae, while parasitoid adults should not be stored for more than 4 days at either 5 or 10°C.     

Genetic population structure and low genetic diversity in the over-exploited sea cucumber <Emphasis Type="Italic">Holothuria edulis</Emphasis> Lesson, 1830 (Echinodermata: Holothuroidea) in Okinawa Island

Understanding genetic connectivity is fundamental for ecosystem-based management of marine resources. Here we investigate the metapopulation structure of the edible sea cucumber Holothuria edulis Lesson, 1830 across Okinawa Island, Japan. This species is of economic and ecological importance and is distributed from the Red Sea to Hawai‘i. We examined sequence variation in fragments of mitochondrial cytochrome oxidase subunit I (COI) and 16S ribosomal RNA (16S), and nuclear histone (H3) at six locations across Okinawa Island. We found higher haplotype diversity for mtDNA (COI: Hd = 0.69 and 16S: Hd = 0.67) and higher heterozygosity of nDNA (H3: H _E = 0.39) in populations from the west coast of Okinawa compared to individuals from populations on the east coast (COI: Hd = 0.40; 16S: Hd = 0.21; H3: H _E = 0.14). Overall population structure was significant (AMOVA results for COI: Φ _ST = 0.49, P < 0.0001; 16S: Φ _ST = 0.34, P < 0.0001; H3: Φ _ST = 0.12, P < 0.0001). One population in the east, Uruma, showed elevated pairwise Φ _ST values in comparisons with all other sites and a marked reduction of genetic diversity (COI: Hd = 0.25 and 16S: Hd = 0.24), possibly as a consequence of a shift to a more dominant asexual reproduction mode. Recent reports have indicated that coastal development in this area influences many marine organisms, and ecosystem degradation in this location could cause the observed decrease of genetic diversity and isolation of H. edulis in Uruma. Our study should provide valuable data to help with the urgently needed management of sea cucumber populations in Okinawa, and indicates particular attention needs to be paid to vulnerable locations.     

Bacterial metabolites from intra- and inter-species influencing thermotolerance: the case of <Emphasis Type="Italic">Bacillus cereus</Emphasis> and <Emphasis Type="Italic">Geobacillus stearothermophilus</Emphasis>

Bacterial metabolites with communicative functions could provide protection against stress conditions to members of the same species. Yet, information remains limited about protection provided by metabolites in Bacillus cereus and inter-species. This study investigated the effect of extracellular compounds derived from heat shocked (HS) and non-HS cultures of B. cereus and Geobacillus stearothermophilus on the thermotolerance of non-HS vegetative and sporulating B. cereus. Cultures of B. cereus and G. stearothermophilus were subjected to HS (42 or 65 °C respectively for 30 min) or non-HS treatments. Cells and supernatants were separated, mixed in a combined array, and then exposed to 50 °C for 60 min and viable cells determined. For spores, D values (85 and 95 °C) were evaluated after 120 h. In most cases, supernatants from HS B. cereus cultures added to non-HS B. cereus cells caused their thermotolerance to increase (D ₅₀ 12.2–51.9) when compared to supernatants from non-HS cultures (D ₅₀ 7.4–21.7). While the addition of supernatants from HS and non-HS G. stearothermophilus cultures caused the thermotolerance of non-HS cells from B. cereus to decrease initially (D ₅₀ 3.7–7.1), a subsequent increase was detected in most cases (D ₅₀ 18–97.7). In most cases, supernatants from sporulating G. stearothermophilus added to sporulating cells of B. cereus caused the thermotolerance of B. cereus 4810 spores to decline, whereas that of B. cereus 14579 increased. This study clearly shows that metabolites in supernatants from either the same or different species (such as G. stearothermophilus) influence the thermotolerance of B. cereus.     

Range expansion and increasing impact of the introduced wasp <Emphasis Type="Italic">Aphidius</Emphasis><Emphasis Type="Italic">matricariae</Emphasis> Haliday on sub-Antarctic Marion Island

Despite the significance of biological invasions in the Antarctic region, understanding of the rates of spread and impact of introduced species is limited. Such information is necessary to develop and to justify management actions. Here we quantify rates of spread and changes in impact of the introduced wasp Aphidius matricariae Haliday, which parasitizes the invasive aphid Rhopalosiphum padi (L.), on sub-Antarctic Marion Island, to which the wasp was introduced in ca. 2001. Between 2006 and 2011, the wasp had colonised all coastal sites, with an estimated rate of spread of 3–5 km year^?1. Adult abundance doubled over the period, while impact, measured as mean percentage parasitism of R. padi, had increased from 6.9 to 30.1 %. Adult wasps have thermal tolerances (LT50s) of between ?18 and 33.8 °C, with a crystallization temperature of ?22.9 °C, and little tolerance (ca. 37 h) of low humidity at 10 °C. Desiccation intolerance is probably limiting for the adult wasps, while distribution of their aphid host likely sets ultimate distributional limits, especially towards higher elevations where R. padi is absent, despite the presence of its host grass on the island, Poa cookii (Hook. f.). Rising temperatures are benefitting P. cookii, and will probably do the same for both R. padi and A. matricariae. Our study shows that once established, spread of introduced species on the island may be rapid, emphasizing the importance of initial quarantine.