上海崇明东滩须浮鸥繁殖期雏鸟生长初步研究及首次雏鸟环志和彩色旗标

2005年夏季,对在崇明东滩繁殖孵化的须浮鸥Chlidonias hybrida雏鸟生长进行了研究,发现雏鸟孵化后至具飞行能力之前体重日增重3.52 g,时间为21天。此外,对29只雏鸟进行了国内首次的环志和彩色旗标系放工作。     

Population‐level traits that affect,and do not affect,invasion success

What allows some species to successfully colonize a novel environment while others fail? Numerous studies in invasion biology have sought to answer this question, but those studies have tended to focus on traits of species or individuals (e.g. body size, seed size, seed number), and these traits have largely been found to be weak predictors of invasion success. However, characteristics of colonizing populations (e.g. genetic diversity, density, age structure) might also be important for successful establishment, as the authors of a study published in this issue of Molecular Ecology show ( Crawford & Whitney 2010 ). By experimentally manipulating the density and genetic diversity of colonizing populations of Arabidopsis thaliana, the authors found that genetic diversity, but not population density, increased colonization success. Importantly, the effects of genetic diversity on colonization success were both additive and non‐additive, suggesting that traits associated with particular genotypes and complimentarity among genotypes contribute to colonization success. This research highlights the importance of considering within‐species variation and characteristics of entire populations in predicting colonization success.     

Enrichment materials do not negatively affect reproductive success and offspring survival and weight in mice

Environmental enrichment is designed to improve the overall welfare of laboratory animals, including mice. Few studies have directly assessed the effects of different types of enrichment on mouse offspring survival and growth. The authors examined how survival and growth of C57BL/6 mouse pups are affected by three kinds of cage enrichment materials: compressed cotton squares, two-ply tissues and plastic igloos. During the last week of gestation and the first two weeks postpartum, the authors observed cages with litters and noted use of the enrichment materials, quality of nest construction, number of pups per litter and weight of pups. Both the first and second litters were evaluated for each dam. Dams and pups had continuous contact with the enrichment materials, especially cotton squares and tissues. Neither the presence nor the type of enrichment material influenced the survival and weight of offspring, suggesting that the use of such materials does not negatively impact reproductive success or offspring survival.     

Different diets and amino acid supplementation do not affect the voluntary consumption of ethanol by rats

The effects of four different diets (control diet: 19.5% protein, 60.5% carbohydrate, 10% fat; diet I: 65% protein, 10% carbohydrate, 10% fat; diet II: 5% protein, 76% carbohydrate, 10% fat; diet III: 20% protein, 69% carbohydrate, 1% fat; diet IV: 69% protein, 15% carbohydrate, 1% fat) and supplementation with 3 amino acids (tryptophan: 150 mg/kg/d; arginine: 400 mg/kg/d; taurine: 380 mg/kg/d) on the voluntary consumption of ethanol were investigated in rats using the 2 bottle method. First, rats received the control diet and diets I, II, III and IV for 20 days with a choice of ethanol for the last 6 days only. Ethanol consumption was similar in all dietary groups. Second, rats received the control diet for 8 days followed by diets I, II and IV for another 8 days. Ethanol was offered throughout both periods. The switch to the special diets did not affect ethanol consumption. Third, rats received a control diet with arginine, tryptophan or taurine added to the drinking fluids for 16 days with a choice of ethanol for the last 5 days; thereafter supplementation stopped but the ethanol choice remained. No difference in the voluntary intake of ethanol was noted but ethanol consumption fell after cessation of arginine supplementation. In conclusion, diets differing greatly in their composition or supplementation with these 3 amino acids did not affect the voluntary choice of ethanol by rats in a significant manner.     

Capture and blood sampling do not affect foraging behaviour, breeding success and return rate of a large seabird: the black-browed albatross

During the last decades, eco-physiological studies have usually relied on the collection of blood from wild organisms in order to obtain relevant physiological measures. However, accurate estimates of the impact of capture and blood collection on performances of Polar seabird species have rarely been conducted. We investigated for the first time the effects of a blood sampling process on subsequent foraging behaviour, reproductive performance and return rate of black-browed albatrosses (Thalassarche melanophris) at Kerguelen Islands. We did not find any evidence that the blood sampling process as conducted in our study had detrimental effects on the breeding or foraging strategies or performance of black-browed albatrosses. Because blood collection can be performed in several different ways, we recommend that eco-physiologists conduct pilot studies to test whether their blood sampling process affects the performances of their study species.     

The slug parasitic nematode Phasmarhabditis hermaphrodita associates with complex and variable bacterial assemblages that do not affect its virulence

Phasmarhabditis hermaphrodita is a nematode parasite of slugs that is commercially reared in monoxenic culture with the bacterium Moraxella osloensis and sold as a biological molluscicide. However, its bacterial associations when reared in vivo in slugs are unknown. We show that when reared in vivo in slugs, P. hermaphrodita does not retain M. osloensis and associates with complex and variable bacterial assemblages that do not influence its virulence. This is in marked contrast to the entomopathogenic nematodes that form highly specific mutualistic associations with Enterobacteriaceae that are specifically retained during in vivo growth.     

Different seasonal rearing conditions do not affect pheromone-sensitive receptor neurons of the adult cabbage looper moth, Trichoplusia ni

Abstract. In southern parts of the United States the cabbage looper moth, Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), is multivoltine, and therefore successive generations experience different environmental conditions during development from larvae to adults.Since environmental conditions are thought to influence pheromone communication, we tested the effects of two different temperature and light regimes (selected to mimic those occurring in the spring and summer growing seasons in the south) during rearing on the response characteristics of the adult male olfactory receptor neurons responsible for detecting the major component of the female pheromone.The dose-response functions of receptor neurons from the warm- and cold-reared insects were similar in both their slopes and thresholds to stimulation with the major component of the female-emitted pheromone, (Z)-7, dodecen-1-ol acetate and (Z)-7, dodecen-1-ol, a behavioural inhibitor.In double pulse experiments, designed to emulate the temporal dispersion of pheromone in nature, neurons were stimulated with short pulses (200 ms) of (Z)-7, dodecen-1-ol acetate separated by varying intervals.Intervals as short as 30 ms reduced the response to a second pulse by over 50%.When the intervals between pulses were longer than 2 s, significant differences were not seen between the responses to the first and to the second pulse.These temporal response patterns were similar in both warm- and cold-reared animals.     

Colored plastic and metal leg bands do not affect survival of Piping Plover chicks

ABSTRACT Leg bands are commonly used to mark shorebird chicks as young as 1‐d old, but little is known about the possible impacts of bands on survival of prefledging shorebirds. We used a mark‐recapture framework to assess the impact of bands and banding‐related disturbance on prefledging survival in a federally endangered population of Piping Plovers (Charadrius melodus) breeding in the Great Lakes region from 2000 to 2008. We banded approximately 96% of all surviving chicks hatched prior to fledging, typically between 5 and 15 d of age. We used a multistate approach in program MARK whereby individuals contributed data as unbanded chicks before capture (N= 1073) and as banded chicks afterward (N= 780). The cumulative probability of surviving through 24 d of age was 0.63 and did not differ between banded and unbanded chicks. In addition, we found a positive effect of banding‐related disturbance on survival up to 3 d following banding (β= 0.60 CI: 0.17–1.02), possibly due to increased postbanding vigilance on the part of chicks and adults. Our results indicate that banding has no detrimental effect on survival of Piping Plover chicks prior to fledging and that current capture and banding methods are appropriate for this endangered species.     

Bioreactor magnetic fields do not affect growth and antibody productivity of GAP-A3 hybridomas

Summary GAP-A3 hybridoma cells grown in T-flasks exposed to the rotating magnetic field of a spinner flask stirrer base show no effect of stirrer speed in the range 0–150 rpm on their growth rate or antibody productivity. Similarly mechanically and magnetically driven spinner flasks at 48 and 70 rpm show no difference in these rates that may be attributed to the magnetic field.     

Leaf domatia do not affect population dynamics of the predatory mite Iphiseiodes zuluagai

Leaves of plants of several families possess small cavities or tufts of hair where leaf veins bifurcate. These so-called acarodomatia are usually inhabited by predatory and fungivorous mites, which utilize domatia as shelter against adverse conditions or against other predators and cannibals. Plants may benefit from the presence of the mites through reduced densities of herbivores or plant-pathogenic fungi. It has therefore been suggested that domatia mediate a mutualistic interaction between plants and mites. We tested the hypothesis that cavity-like domatia on coffee plants benefit the predatory mite Iphiseiodes zuluagai through providing protection against adverse weather conditions and other predators in three field experiments. We manipulated plant domatia by blocking all on one group of plants, whereas a second group of plants with open natural domatia served as a control. Predatory mite populations were provided with pollen as a food source during part of two experiments. Experiments were done in the dry and rainy season to test the effects of adverse weather conditions and with or without an insect glue barrier on the plant to prevent access of ground-dwelling hyperpredators. High temperatures had a significant negative effect on predator densities in all experiments, whereas rainfall and humidity affected densities in one and two experiments respectively. None of the experiments showed a significant effect of domatia manipulation on mite numbers, or a significant interaction between weather parameters and domatia, suggesting that domatia did not protect against these adverse weather conditions. Nevertheless, predatory mites were frequently observed inside the domatia, suggesting that the mites benefit from using domatia. Perhaps domatia offer protection against hyperpredators, which were rarely observed during our experiments.     

Unlike thrombin, protein C and activated protein C do not affect vascular tone

Because plasma levels of protein C (PC) or activated protein C (APC) are altered in certain diseases associated with vascular dysfunction, and APC has therapeutic potential in preventing microvascular coagulation in severe sepsis, potential vascular effects of PC and APC were compared to those of the vasoactive peptide, thrombin. Thrombin was a more potent relaxant agonist than contractile agonist in aorta. Unlike thrombin, cumulatively administered APC (10(-9)-10(-7) M) did not exert vascular effects in rat or rabbit aorta. Noncumulative challenge of PC (10(-7) M) and APC (8 x 10(-8) M) also did not contract rat or rabbit aortae, either with or without endothelium. Likewise, the same concentrations of PC and APC also did not relax norepinephrine-induced (10(-7) M) vascular tone in either rat or rabbit aortae. Thus, in contrast to thrombin, PC and APC failed to modulate vascular tone, suggesting that the therapeutic use of APC is unlikely to be accompanied by any direct effects on vascular motility.     

Externally attached radio transmitters do not affect the parental care behaviour of rock bass

Turning, pectoral fin and caudal fin rates and time spent on the nest of male rock bass Ambloplites rupestris , engaged in parental care, were not affected after the attachment of external radio transmitters. Reproductive success was similar between treatment and control fish. Micro external radio transmitters can be used on small fishes for studying parental care duration and post-care movement without altering their behaviour.     

Photoperiod and pinealectomy do not affect cold-induced deposition of brown adipose tissue in the long-evans rat

Brown adipose tissue is a major thermogenic effector of cold-induced nonshivering thermogenesis. Previous studies indicate that melatonin and/or short photo-period are involved in the increase in brown fat deposition seen in certain cold-acclimated rodents. The present study was undertaken, in part, to determine whether the pineal is a necessary component in the cold-induced increase in thermogenic capacity characteristic of the cold-acclimated laboratory rat. Under a 12L:12D light cycle, pinealectomized rats did not differ from sham-operated rats in their ability to increase brown fat deposition in the cold (5 °C). Moreover, in a subsequent set of experiments performed at 9 °C, intact rats maintained at a short photoperiod (9L:15D) exhibited the same degree of brown fat hypertrophy/hyperplasia as did those kept at a long photoperiod (15L:9D). These data thus indicate that: (a) the intact pineal is not necessary for the cold-induced increase in brown adipose tissue occurring in the cold-acclimated rat; and (b) photoperiod does not significantly modulate the magnitude of this increase.     

Estrogen and gender do not affect fatigue resistance of extensor digitorum longus muscle in rats.

The effects of estrogen on skeletal muscle fatigue are controversial. To determine the effects of estrogen and gender on rat extensor digitorum longus (EDL) muscle, we either injected 40 microg beta-estradiol 3/benzoate.kg BW(-1) to female rats or sham injected male or female rats for 14 days. Subsequently a 90 min fatigue protocol consisting of electrical stimulation at 10 Hz delivered in 500 ms trains was administered. Force was recorded for a 5 s period at the start of the protocol (0 min) and at 5 min intervals until completion following 90 min of stimulation. After 90 min, EDL force generation at 10 Hz stimulation declined in all groups to between 50-60 % of initial values. However, no significant difference in fatigue rate or final 10 Hz stimulated force was seen between females administered estrogen, sham injected females or males. Hence, estrogen administration and gender did not significantly affect EDL muscle fatigue in this model.     

Studies of Pseudomonas aeruginosa azurin mutants: cavities in beta-barrel do not affect refolding speed

Pseudomonas aeruginosa azurin is a blue-copper protein with a Greek-key fold. Removal of copper produces an apoprotein with the same structure as holoazurin. To address the effects on thermodynamic stability and folding dynamics caused by small cavities in a beta-barrel, we have studied the behavior of the apo-forms of wild-type and two mutant (His-46-Gly and His-117-Gly) azurins. The equilibrium- and kinetic-folding and unfolding reactions appear as two-state processes for all three proteins. The thermodynamic stability of the two mutants is significantly decreased as compared with the stability of wild-type azurin, in accord with cavities in or near the hydrophobic interior having an overall destabilizing effect. Large differences are also found in the unfolding rates: the mutants unfold much faster than wild-type azurin. In contrast, the folding-rate constants are almost identical for the three proteins and closely match the rate-constant predicted from the native-state topology of azurin. We conclude that the topology is more important than equilibrium stability in determining the folding speed of azurin.     

Biological control as an invasion process: disturbance and propagule pressure affect the invasion success of Lythrum salicaria biological control agents

Understanding the mechanisms behind the successful colonization and establishment of introduced species is important for both preventing the invasion of unwanted species and improving release programs for biological control agents. However, it is often not possible to determine important introduction details, such as date, number of organisms, and introduction location when examining factors affecting invasion success. Here we use biological control introduction data to assess the role of propagule pressure, disturbance, and residence time on invasion success of four herbivorous insect species introduced for the control of the invasive wetland plant, Lythrum salicaria, in the Columbia River Estuary. Two sets of field surveys determined persistence at prior release sites, colonization of new sites, and abundance within colonized sites. We quantified propagule pressure in four ways to examine the effect of different measurements. These included three measurements of introduction size (proximity to introduction site, introduction size at a local scale, and introduction size at a regional scale) and one measure of introduction number (number of introduction events in a region). Disturbance was examined along a tidal inundation gradient (distance from river mouth) and as habitat (island or mainland). Statistical models and model averaging were used to determine which factors were driving invasion success. In this study we found: (1) sparse evidence for the positive influence of propagule pressure on invasion success; (2) disturbance can negatively affect the invasion success of herbivorous insects; (3) the effects of disturbance and propagule pressure are species specific and vary among invasion stages, and (4) not all measures of propagule pressure show the same results, therefore single measures and proxies should be used cautiously.     

Nest orientation and hatching success of Black Kites Milvus migrans in Spain

An analysis of the orientation of 182 nest sites of the Black Kite Milvus migrans in two areas in south and central Spain found that orientations toward the east were preferred. In southern Spain an analysis of the relationship between nest orientation and hatching success showed that success was lower among the nests located in non-preferred orientations, with some inter-annual variation. The tendency to orientate nests toward the east was greater among the early nesting pairs and the effect that the orientation had on the hatching success was also greater than in late nesting pairs. The data suggest that rainfall and prevailing winds were the main factors conditioning nest orientation.