Larval history influences post-metamorphic condition in a coral-reef fish

Upon settlement, many fishes undergo an energetically costly metamorphic period that requires substantial nutritional reserves. Larval growth and the accumulation of lipids prior to metamorphosis are likely to influence growth and survival following this critical period. On the Caribbean island of St. Croix, I investigated relationships between larval growth, early life-history characteristics, and post-metamorphic lipid content in the bluehead wrasse Thalassoma bifasciatum. Lipid reserves remaining after metamorphosis were positively related (r2 = 0.62) to the width of the metamorphic band; thus, this otolith-derived trait may be used to estimate the condition at emergence of survivors collected at some later time. In contrast, pelagic larval duration, average larval growth, and otolith size at settlement were negatively related to post-metamorphic lipid content. Interestingly, the trend for slower growth among fish in good condition was not consistent over the entire pelagic larval duration. Analyses of daily larval growth histories indicated that fish with high lipid reserves grew rapidly in the last week prior to settlement, but relatively slowly during the early phases of larval life; those emerging with low lipid concentrations, however, displayed strikingly opposite patterns. These contrasting patterns of growth and energy storage were consistent at two sites and over three recruitment events. Otolith chemistry data suggested that differences in growth histories and body condition were consistent with the hypothesis of larval development in distinct oceanic environments (characterized by Pb concentration); but, within a water mass, differences reflected life-history trade-offs between growth and energy storage. The results have implications for understanding the processes driving juvenile survival, which may be condition dependent.     

Do male mealworm beetles, <Emphasis Type="Italic">Tenebrio molitor</Emphasis>, sustain the honesty of pheromone signals under immune challenge?

Immune function is potentially costly and traded-off against the expression of sexual signals, thus, making sexual advertisement a condition-dependent and honest indicator of current immunocompetence. We conducted a series of laboratory experiments using mature mealworm beetles, Tenebrio molitor, to examine whether an immunological challenge (nylon implant(s), microbial lipopolysacharides, microlatex beads) could affect the attractiveness of male pheromones or male’s survival in ad libitum and ‘water-only’ food regimes or whether pheromones signal more long-term qualities of males. We treated another set of newly-emerged males with a single nylon implant and gave first ad libitum food but later only water. We used several immune challengers and feeding regimes to examine if the expected trade-off between immune function and sexual signaling would be expressed differently depending on the resource level and the type of the immune challenge. None of the treatments affected the female preference for male pheromones or the male longevity except for the acute mortality caused by two-implant treatments. However, males lost less body mass when immune challenged and given an opportunity to feed. We conclude that females seem to prefer certain males, and the effect of immune challenge in males cannot systematically override these preferences.     

苹果渣发酵生产饲料蛋白的工艺条件

采用经试验所筛选出的菌种组合,通过试验,获得了苹果渣发酵的适宜工艺条件：接种比例为１∶５-１∶１０,接种量１５-３０％ ,料水比１０∶７-１０∶８,ｐ Ｈ 值为６-７,发酵时间 ３-４ｄ,静止发酵料层厚度不超过３０ｍ ｍ 。发酵产物测定结果显示,粗蛋白含量达到２９３０％ ,提高了４５７７％ ,蛋白质含量达到２７５６％ ,提高了８２８８％ ,粗纤维含量降低了２３２７％ 。测定结果还进一步显示,所选菌种具有明显的脱毒作用,棉酚含量降低９０６３％ 。大部分氨基酸含量较发酵原料显著增加,蛋白质营养价值明显提高。     

产木聚糖酶的沿海红树林真菌筛选及其培养与酶活测定条件优化

从香港海岸红树林分离到的 77株真菌中有 34株可产生木聚糖酶 ,从中选出CY2 80 9(Staganosporasp .)、CY4 786和CY5 0 4 0等 3菌株与已知陆生产酶菌株HU5 0 4 8(Aspergillusawamori)进行产木聚糖酶的比较研究。根据培养液中菌丝生物量、木聚糖酶活力和木糖等价还原糖含量等指标的测定 ,菌株CY4 786在起始pH 7 8的木聚糖 酵母膏 海盐液体培养基中 2 5℃下震荡 (10 0r min)培养 7d产酶最佳 ;粗酶液在 5 0℃和pH 4 6的优化条件下进行测定 ,木聚糖酶活力达到 1 0 7× 10 4 U mL。结果表明 ,红树林真菌起着半纤维素降解者的作用 ,沿海红树林环境中存在着可资利用的木聚糖酶产生菌。作者讨论了利用发酵液中木糖等价还原糖含量的动态变化作为快速筛选产木聚糖酶菌株的指标的可能性     

Mating habits of the rockfishSebastes inermis

Synopsis Underwater observations were conducted on the mating habits of rockfish,Sebastes inermis, southwest of Kyushu Island, Japan, in 1984–1986. The reproductive season of the fish lasted from October to January, when most males over 1 year of age established territories ranging from 12 to 70 m². Home ranges of females overlapped with male territories. Males performed courtship behaviors when females approached the territories. Principal motor patterns of courtship were characterized by ‘lateral display’ and ‘rushing and turning’ movements. The mating pair formed about 30 min before copulation. As the mating pair ascended to 1.5–2.0 m above the bottom, the male suddenly coiled around the female's body to copulate. In spite of frequent courtship behavior [14.8 (±10.7 SD)×15 min⁻¹, December 1985] of males, only seven copulations were observed, occurring mostly at dusk in December. In December and January, more than half of the males had accumulated urine, some large volume of it. It was assumed that the male attracted the female by releasing substances via urine during the ‘lateral display’ movements, which were performed just in front of the female, near the snout. Other functional aspects of courtship behavior are discussed.     

Ontogenetic timing as a condition‐dependent life history trait: High‐condition males develop quickly,peak early,and age fast

Within‐population variation in ageing remains poorly understood. In males, condition‐dependent investment in secondary sexual traits may incur costs that limit ability to invest in somatic maintenance. Moreover, males often express morphological and behavioral secondary sexual traits simultaneously, but the relative effects on ageing of investment in these traits remain unclear. We investigated the condition dependence of male life history in the neriid fly Telostylinus angusticollis. Using a fully factorial design, we manipulated male early‐life condition by varying nutrient content of the larval diet and, subsequently, manipulated opportunity for adult males to interact with rival males. We found that high‐condition males developed more quickly and reached their reproductive peak earlier in life, but also experienced faster reproductive ageing and died sooner than low‐condition males. By contrast, interactions with rival males reduced male lifespan but did not affect male reproductive ageing. High‐condition in early life is therefore associated with rapid ageing in T. angusticollis males, even in the absence of damaging male–male interactions. Our results show that abundant resources during the juvenile phase are used to expedite growth and development and enhance early‐life reproductive performance at the expense of late‐life performance and survival, demonstrating a clear link between male condition and ageing.     

Biology of the rainbowfish,Glossolepis multisquamatus (Melanotaeniidae), from the Sepik River floodplains,Papua New Guinea

Synopsis G. multisquamatus is abundant in the Sepik River, preferring floodplain lakes and marginal areas of floodplain with moderate turbidity. It is the only rainbowfish documented to inhabit river floodplains. Migrations onto and off the floodplain occur in response to changes in flood conditions. Seasonality is evident in reproduction, condition factor and fat deposit and stomach fullness indices; all increasing in the flood season. Fecundity is high compared with stream dwelling rainbowfish species mainly due to decreased egg size. The reproductive strategy ofG. multisquamatus is interpreted as a response to increased adult mortalities encountered on floodplains in comparison to more stable stream habitats occupied by related species.G. multisquamatus is carnivorous, its diet being similar to other rainbowfishes, consisting of a variety of small invertebrates taken from mid-water or the water surface. The ecology and behaviour ofG. multisquamatus is explained as a partial colonisation of newly developed floodplains in this river.     

The reproductive biology of an endemic cyprinid,Zacco pachycephalus,in Taiwan

Synopsis Reproductive parameters including body weight-length relationship, condition factor, gonadosomatic index (GSI) and fecundity of an endemic cyprinid,Zacco pachycephalus, were studied from October 1991 to January 1993. Although the condition factor was similar between both sexes, GSI values of female (3.72 to 14.24%) were significantly larger than that of males (0.21 to 2.23%) during the major breeding season. The number of yolky eggs per fish ranged from 459 to 2059. Ovum size distribution, annual GSI value, and recruitment of juvenile fish indicated thatZ. pachycephalus conducted two major spawning activities in spring (February to April) and summer (June to August). The larger GSI value and number of yolky eggs in spring compared to those in summer implies thatZ. pachycephalus has evolved a reproductive style by investing more energy in spring to avoid the damage of summer freshet on its recruitment success. The mating behavior ofZ. pachycephalus is similar to that of otherZacco fishes.     

阻塞性睡眠呼吸暂停低通气综合征血压变异性及运动心肺功能与病情的相关性分析

目的:探讨阻塞性睡眠呼吸暂停低通气综合征(OSAHS)血压变异性及运动心肺功能与病情的相关性分析。方法:选取2017年2月～2018年11月期间我院收治的OSAHS患者119例为研究对象,根据每小时睡眠呼吸暂停次数(AHI)将患者分为轻度组(AHI:5～20次/h,n=45)、中度组(AHI:21～40次/h,n=39)、重度组(AHI:40次/h,n=35),检测所有研究对象的血压变异性及运动心肺功能,并作组间比较。采用Pearson积矩相关分析OSAHS患者血压变异性及运动心肺功能与病情的相关性。结果:OSAHS患者收缩压(SBP)昼、舒张压(DBP)夜以及中度组、重度组SBP夜均高于对照组(P0.05);重度组DBP夜以及中度组、重度组SBP昼、SBP夜高于轻度组(P0.05);重度组SBP夜、SBP昼、DBP夜高于中度组(P0.05);而各组DBP昼整体比较差异无统计学意义(P0.05)。OSAHS患者最大摄氧量占预计值百分比(VO2max%pred)、最大摄氧量峰值占预计值百分比(peak VO2%pred)、无氧阈值(AT)、摄氧量功率比值(VO2/WR)、呼吸储备(VEmax/MVV)均低于对照组,且随病情严重程度的增加而降低(P0.05),OSAHS患者二氧化碳通气当量(VE/VCO2)高于对照组,且随病情严重程度的增加而升高(P0.05)。Pearson积矩相关分析结果显示,OSAHS患者病情严重程度与SBP昼、SBP夜、DBP夜、VE/VCO2呈正相关(P0.05),与VO2max%pred、peakVO2%pred、AT、VEmax/MVV、VO2/WR呈负相关(P0.05),与DBP昼无相关性(P0.05)。结论:血压变异性及运动心肺功能指标可反映OSAHS患者病情严重程度,可考虑作为早期监测指标并参考指导治疗。     

Body condition threshold for breeding in a viviparous snake

One major goal of physiological ecology is to seek links between life history traits. Identification of a body condition threshold for breeding (e.g. critical level of body reserves) provides a link between the physiological process involved in storage of body reserves and the ability to reproduce. One hundred and twenty-nine freeranging adult female Vipera aspis, a viviparous snake, were marked with electronic identification tags and/or by scale clipping, weighed, and measured at the onset of vitellogenesis, and immediately released in the field in western central France (47°03N; 02°00W). The 129 snakes were recaptured 2–6 months later between ovulation and parturition, and individual reproductive status was then determined. Eighty-four females (65%) captured at the onset of vitellogenesis became vitellogenic, 45 did not. There was no difference in mean body length between reproductive and non-reproductive females. Initial body condition influenced reproductive outcome: we found a precise threshold in body condition necessary for the induction of vitellogenesis. Almost all females (88%) with a body condition greater than the observed threshold became vitellogenic, 12% did not, and no female with a body condition under the threshold became vitellogenic. Body reserves were estimated in the 129 living females using data gathered on 69 autopsied females. Females which became vitellogenic had large body reserves, but females which did not were not particularly emaciated (whilst postparturiant females had few body reserves remaining). This precise condition threshold for breeding is discussed in terms of the reproductive ecology of this species.