Increased ambient temperature alters the parental care behaviour and reproductive success of the three-spined stickleback (<Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis>)

The effects of environmental warming on aquatic poikilotherms, such as fish, are likely to be manifest during periods of high metabolic demand. For species that invest heavily in parental-care, such as the three-spined stickleback, Gasterosteus aculeatus L., their reproductive success may be adversely affected. In two separate experiments with temperatures raised by 2°C to 6°C above 16–17°C ambient over a whole breeding season, we quantified changes to parental-care behaviour and the resultant reproductive success of G. aculeatus. As temperature increased, male parental-care behaviour was altered, particularly the fanning of the fertilised eggs. Fanning behaviour was highly variable among individual fish however it increased over the course of incubation. Furthermore, all egg incubating fish consistently fanned at a faster rate in higher temperatures. The male fish responded to the increased temperature by putting more effort into fanning. The consequence was that these fish had a higher rate of incubation failure and an increased likelihood of mortality. The pattern of alteration to parental care behaviour and decreased reproductive success with higher temperature was remarkably consistent across the individual fish, which suggests consequences at the population level of increased ambient temperatures.     

δ18O‐derived incubation temperatures of oviraptorosaur eggs

In order to determine the incubation temperature of eggs laid by non‐avian dinosaurs, we analysed the oxygen isotope compositions of both eggshell carbonate (δ¹⁸O_c) and embryo bone phosphate (δ¹⁸O_p) from seven oviraptorosaur eggs with preserved in ovo embryo bones. These eggs come from the Upper Cretaceous Nanxiong Formation of Jiangxi Province, China. Oviraptorosaur theropods were selected because of their known brooding behaviour as evidenced by preserved adult specimens fossilized in brooding posture on their clutch. Incubation temperature of these embryos was estimated based on the following considerations: eggshell δ¹⁸O_c value reflects the oxygen isotope composition of egg water fluid; embryo bones precipitate from the same egg fluid; and oxygen isotope fractionation between phosphate and water is controlled by the egg temperature. A time‐dependent model predicting the δ¹⁸O_p evolution of the embryo skeleton during incubation as a function of egg temperature was built, and measured δ¹⁸O_c and δ¹⁸O_p values used as boundary conditions. According to the model outputs, oviraptorosaurs incubated their eggs within a 35–40°C range, similar to extant birds and compatible with the known active brooding behaviour of these theropod dinosaurs. Provided that both eggshell and embryo bones preserved their original oxygen isotope compositions, this method could be extended to investigate some reproductive traits of other extinct groups of oviparous amniotes.     

Beiträge zur Ethologie und Phylogenie der Familie Belontiidae (Anabantoidei,Pisces)

The behaviour of the dragonfly E. fatime was observed in the field in the Near East, in Turkey and on Rhodos in the summers of 1971 and 1973. A short ethogram of the species is given and its behaviour compared with that of other dragonflies. On this basis its phylogenetic position is discussed.     

Über den Einfluß sozialer Isolation auf die Rangordnungskämpfe männlicher Schwertträger (Xiphophorus helleri12

The question is, if intraspecific aggressive behaviour can be understood as a drive. If Xiphophorus helleri ♂♂ are kept in social isolation for 7–56 days, the fights for rank order position showed an increasing duration and intensity (S-curving, ramming, circling and mouth-fighting are registered by an event-recorder. These results are in contrast to the results on cichlids and anabantids. The results can be explained by the idea of a spontaneous accumulation of attack readiness or as recovery from habituation. It is supposed that the different influence of social isolation on aggressive behavior corresponds to different types of social organization and ecological adaptations.     

High Temperature Stimulates <Emphasis Type="Italic">DWARF4 (DWF4)</Emphasis> Expression to Increase Hypocotyl Elongation in <Emphasis Type="Italic">Arabidopsis</Emphasis>

Hypocotyl growth occurs as a result of an interaction between environmental factors and endogenous phytohormones. In Arabidopsis, high temperature promotes auxin synthesis to increase hypocotyl growth. We previously showed that exogenously provided auxin stimulates expression of the brassinosteroid (BR) biosynthetic gene DWARF4. To determine whether temperature-induced hypocotyl elongation depends on BR biosynthesis, we examined the morphological responses to high temperature and the expression pattern of DWF4pro:GUS in different genetic backgrounds, which are as follows: Ws-2 wild-type, iaa19/msg2, bri1-5, and dwf7-1. In contrast to the wild-type, growth of the three genotypes at 29°C did not significantly increase hypocotyl length; whereas, with the exception of iaa19/msg2, the roots were elongated. These results confirm that BR biosynthesis and signaling pathways are required for hypocotyl growth at high temperature. Furthermore, a GUS histochemical assay revealed that a temperature of 29°C greatly increased DWF4pro:GUS expression in the shoot and root tips compared to a temperature of 22°C. Quantitative measurements of GUS activity in DWF4pro:GUS revealed that growth at 29°C is similar to the level of growth after addition of 100 nM IAA to the medium. Our results suggest that temperature-dependent synthesis of free auxin stimulates BR biosynthesis, particularly via the key biosynthetic gene DWF4, and that the BRs thus synthesized are involved in hypocotyl growth at high temperature.     

Consequences of temperature and temperature variability on swimming activity,group structure,and predation of endangered delta smelt

相似文献   

The costs of keeping cool in a warming world: implications of high temperatures for foraging,thermoregulation and body condition of an arid‐zone bird

Recent mass mortalities of bats, birds and even humans highlight the substantial threats that rising global temperatures pose for endotherms. Although less dramatic, sublethal fitness costs of high temperatures may be considerable and result in changing population demographics. Endothermic animals exposed to high environmental temperatures can adjust their behaviour (e.g. reducing activity) or physiology (e.g. elevating rates of evaporative water loss) to maintain body temperatures within tolerable limits. The fitness consequences of these adjustments, in terms of the ability to balance water and energy budgets and therefore maintain body condition, are poorly known. We investigated the effects of daily maximum temperature on foraging and thermoregulatory behaviour as well as maintenance of body condition in a wild, habituated population of Southern Pied Babblers Turdoides bicolor. These birds inhabit a hot, arid area of southern Africa where they commonly experience environmental temperatures exceeding optimal body temperatures. Repeated measurements of individual behaviour and body mass were taken across days varying in maximum air temperature. Contrary to expectations, foraging effort was unaffected by daily maximum temperature. Foraging efficiency, however, was lower on hotter days and this was reflected in a drop in body mass on hotter days. When maximum air temperatures exceeded 35.5 °C, individuals no longer gained sufficient weight to counter typical overnight weight loss. This reduction in foraging efficiency is likely driven, in part, by a trade‐off with the need to engage in heat‐dissipation behaviours. When we controlled for temperature, individuals that actively dissipated heat while continuing to forage experienced a dramatic decrease in their foraging efficiency. This study demonstrates the value of investigations of temperature‐dependent behaviour in the context of impacts on body condition, and suggests that increasingly high temperatures will have negative implications for the fitness of these arid‐zone birds.     

Spawning behaviour of Sakhalin taimen, <Emphasis Type="Italic">Parahucho perryi</Emphasis>, from northern Hokkaido,Japan

A video camera mounted in an underwater housing and remotely operated was used to monitor the behaviour of five different Sakhalin taimen (Parahucho perryi), females and attendant males spawning in three coastal tributary streams in Northern Hokkaido, Japan. Based on three complete and two incomplete spawnings, we describe in detail for the first time the complete spawning behavioural repertoire of this species. The Sakhalin taimen was originally placed within Hucho, then removed from that genus based on morphological, life history and molecular data. Our study supports that removal—none of the behavioural traits we recorded clustered Parahucho with Hucho uniquely. Similarities between the two genera were all plesiomorphic traits that are widespread throughout the salmonines. The immediate behaviour right after spawning was found to be a major difference between Hucho and Parahucho. Like female Oncorhynchus and Salmo, Sakhalin taimen females cover their eggs by beats of their tails immediately after spawning. This is different from the “rest, then cover” behaviour shown by Siberian taimen (Hucho taimen) as well as lenok (Brachymystax lenok), supporting again that the Sakhalin taimen be removed from Hucho and placed in its own genus.     

Untersuchungen zur Blütenaffinität der Schachbrettweibchen (Agapetes galathea L.)

Rhopaloceran butterflies are well known to visit distinct species of flowers in order to extract nectar, normally leaving again after a short time to continue their foraging flights. Females of Agapetes galathea, however, often show a different behaviour, which is the subject of the following analysis. The dynamics of sugar production by flowers and the foraging pattern of the galathea- ♂♂ have been studied under natural conditions. Special consideration is given to the aggressive behaviour of the females towards approaching insects during their flower resting periods.     

Territorial behaviour in corn mice, <Emphasis Type="Italic">Calomys musculinus</Emphasis> (Muridae: Sigmodontinae), with regard to mating system

We studied territorial behaviour of Calomys musculinus, a promiscuous-polygynous species, in order to test the predictions that during the breeding period, home-range-owner females are more aggressive than home-range intruders and that males do not display territorial behaviour. At the core of the breeding season, we conducted 136 intrasexual and 66 intersexual encounters. The study was carried out in four 0.25-ha enclosures, each containing one independent population. We studied territorial behaviour utilising focal animal sampling to record behaviour. Encounters were conducted in a circular opaque arena (COA) near the home-range’s activity mathematical centre (AMC). Amicable behaviour was not observed in any of the 78 trials among females. The rates of aggressive and submissive behaviour per female–female encounters varied in relation to whether they were home-range owners or intruders, the former being aggressive, the latter submissive. So we could link these drives to the territorial behaviour of C. musculinus. This result fits well with the already known territoriality of C. musculinus during the breeding season. In contrast, the 58 intrasexual male encounters did not show direct aggressive interactions between them. The rates of the different behaviours between males did not vary in relation to whether they were home-range owners or intruders. In our study, which took place during the breeding period, C. musculinus males were nonterritorial, and they never exhibited aggressiveness towards females.     

Haulout behaviour of High Arctic harbour seals (<Emphasis Type="Italic">Phoca vitulina vitulina</Emphasis>) in Svalbard,Norway

Haulout behaviour of harbour seals, living at the northern limit of their distributional range on Svalbard, Norway, was investigated from June to August 2000 using a combination of low-tide counts performed during boat surveys, hourly counts through 12- or 24-h cycles at specific haulout sites, and telemetric data from 37 VHF-tagged seals. The largest aggregations of seals were found at Skarvnes, a site where numbers increased steadily through the summer, reaching a peak during the moulting period in August. At this site, season/date, time of day, tidal state and temperature all significantly influenced the number of animals ashore. At the second most frequented haulout site, at Sørøya, season/date, time of day, temperature and cloud cover significantly affected the number of seals using the site. Pups were found predominantly at Sørøya (7.8 pups±6.3 SD, N=53 counts); they were less common at Skarvnes (1.0 pups±0.2 SD, N=95 counts). Haulout patterns varied by age and sex class in accordance with the demands of lactation, mating and moult. Our limited data on mother-pup pairs suggest that they are closely associated during the nursing period, spending approximately 50% of their time hauled out together. Post lactation, most adult females left haulout areas for periods of up to several days. The haulout behaviour of adult males suggested that they adjusted their behaviour to follow female distribution and movement patterns during the breeding period. Most juveniles and adults of both sexes stayed ashore for prolonged periods during moulting, which took place first in juveniles, then in adult females and finally in adult males. The results of our study show that the basic haulout behaviour patterns of harbour seals at Svalbard are similar to this species behaviour at lower latitudes.     

Feeding behaviour in the Antarctic fairy shrimp, <Emphasis Type="Italic">Branchinecta gaini</Emphasis>

Direct observations of feeding behaviour in Branchinecta gaini are described. B. gaini possess sophisticated food manipulation behaviours, using their abdominal appendages to ‘scrape’ at and carry away food items. Scraping behaviour was employed by animals for both detrital feeding and the cannibalisation of dead conspecifics. In the absence of like observations from other non-raptatory species of Branchinecta, it appears that adults of B. gaini occupy an intermediary position between species that feed exclusively on vegetative and detrital material and those (e.g. B. gigas, B. ferox, B. raptor) that are known to be carnivorous. In an Antarctic context, particularly, specialisation towards carnivory would have little adaptive value, while expansion of diet breadth via increased manipulative and digestive flexibility would, on the other hand, be advantageous. These behaviours, moreover, mean that B. gaini plays an active role in the breakdown and recycling of its own nutrient base.     

Pathogénie comparée de 4 espèces d'Helminthosporium Obtenues à Partir des Plantes Malades du Riz au Maroc

A comparative study into the pathogenicity of four Helminthosporiumspp. towards rice cultivars in Marocco In this paper, the behaviour of four Helminthosporium species on nine rice cultivars widely cultivated in Morocco, permit the classification of this species according to their virulence. Helminthosporium oryzae and Helminthosporium sativum are the most virulent and the best equipped to sporule on all varieties of tested lesions. The level of pathogenicity of Helminthosporium spiciferum and Helminthosporium australiensis and their capacity to sporule on host plant depend on the rice variety used. At the same time, each Helminthosporium induces characteristics symptoms on rice leaves.     

Behaviour‐related DRD4 polymorphisms in invasive bird populations

It has been suggested that individual behavioural traits influence the potential to successfully colonize new areas. Identifying the genetic basis of behavioural variation in invasive species thus represents an important step towards understanding the evolutionary potential of the invader. Here, we sequenced a candidate region for neophilic/neophobic and activity behaviour – the complete exon 3 of the DRD4 gene – in 100 Yellow‐crowned bishops (Euplectes afer) from two invasive populations in Spain and Portugal. The same birds were scored twice for activity behaviour while exposed to novel objects (battery or slice of apple) in captivity. Response to novel objects was repeatable (r = 0.41) within individuals. We identified two synonymous DRD4 SNPs that explained on average between 11% and 15% of the phenotypic variance in both populations, indicating a clear genetic component to the neophilic/neophobic/activity personality axis in this species. This consistently high estimated effect size was mainly due to the repeated measurement design, which excludes part of the within‐individual nongenetic variance in the response to different novel objects. We suggest that the alternative alleles of these SNPs are likely introduced from the original population and maintained by weak or antagonistic selection during different stages of the invasion process. The identified genetic variants have not only the potential to serve as genetic markers of the neophobic/neophilic/activity personality axis, but may also help to understand the evolution of behaviour in these invasive bird populations.     

Effect of abiotic factors on the foraging strategy of the orb‐web spider Argiope keyserlingi (Araneae: Araneidae)

Abstract Environmental conditions such as light level, background contrast and temperature might influence a spider's prey capture success and risk of predation. Thus it may often be advantageous for spiders to adjust web‐building behaviour in response to variation in these environmental conditions. This hypothesis was examined in a study of the construction of webs and web decorations (conspicuous strands of silk at the hub of the web) of the orb‐web spider Argiope keyserlingi. Web decorations are thought to have one or more separate functions. They may attract prey, deter predators or advertise the web to oncoming birds, thus preventing web damage. In this series of experiments, relationships between weather parameters and the construction of webs and web decorations were considered. In complementary laboratory experiments, A. keyserlingi spiders were exposed to two different light levels (700 and 90 lx), background contrasts (black and white) and temperature conditions (20 and 26°C). Of the available weather parameters, only temperature was significantly related to web decorating behaviour but not to web size. In the laboratory, temperature also influenced web‐decorating behaviour, and spiders in dim light (700 lx) constructed larger webs and longer decorations. Background contrast did not significantly alter web size or web decorations. These data suggest that when prey availability is reduced at low temperatures, spiders may use web decorations to attract prey to the web. Similarly, in dim light, spiders may build more and larger decorations to increase the visual signal to approaching prey or to advertise the web to oncoming birds.     

Female reproductive behaviour,ovarian hormones and vaginal cytology of the induced ovulator, <Emphasis Type="Italic">Ctenomys talarum</Emphasis>

In the present study, we evaluated whether reproductive condition affects female reproductive behaviour in the induced ovulator Ctenomys talarum. We also explored the effect of the interaction with a male on the reproductive condition of females. To evaluate this, we arranged mating trials and evaluated female reproductive behaviour. Reproductive status of females was evaluated using a combined approach of vaginal smears, urinary progesterone and oestradiol, and ovarian histology. Behaviours denoting attraction (‘male sniff’ and ‘mount attempts’) and mutual courtship behaviours (‘spin’ and copula) were correlated with vaginal cytology before and oestradiol and progesterone levels in urine 12 h after male–female encounter. After 24 h of the interaction, oestradiol levels and vaginal epithelization increased while progesterone levels decreased in soliciting females. C. talarum females’ reproductive behaviour was related to its physiological reproductive state and vaginal cytology. The kind of male interaction, whether couples copulated or remained indifferent affected the later status of females. Females are induced ovulators by mating but male presence and interaction also affected other components of their reproductive physiology such as ovarian hormones and vaginal cytology.     

Temporal plasticity in thermal‐habitat selection of burbot Lota lota a diel‐migrating winter‐specialist

In this study, animal‐borne telemetry with temperature sensors was coupled with extensive habitat temperature monitoring in a dimictic reservoir, to test the following hypotheses: behavioural thermoregulation occurs throughout the year and temperature selection varies on a diel and seasonal basis, in a winter‐specialist diel‐migrating fish. Burbot Lota lota demonstrated nightly behavioural thermoregulation throughout the year, with a large seasonal shift between selection for very cold temperatures (<2° C) optimal for reproduction during the spawning period and selection for warmer temperatures (12–14° C) optimal for hunting and feeding during non‐reproductive periods. During daylight hours, while L. lota avoided habitats warmer than optimal for reproduction and feeding during the spawning and non‐reproductive periods, respectively, active selection was limited to selection for 4–6° C habitat during the prespawning period. Although behavioural thermoregulation explained the night‐time migration, behavioural thermoregulation only partially explained daytime behaviour, indicating that diel migration is best explained by a combination of factors. Thus, thermal‐habitat selection was a good predictor of night‐time habitat occupancy in a diel‐migrating species. Together, these results show that thermal‐habitat selection by fishes may be important throughout the year and a more seasonally plastic behaviour than previously recognized.     

Effect of varying environments on photosynthetic parameters of C3, C3-C4 and C4 species of Panicum

Summary CO₂ exchange characteristics and the activity of the carboxylating enzymes phosphoenolpyruvate carboxylase (PEP-C, E.C. 4.1.1.31) and ribulose 1,5-bisphosphate carboxylase (RuBP-C, E.C. 4.1.1.39) during one year in the greenhouse and at two levels of light and temperature in growth chambers were determined in the C₃-C₄ intermediate species P. milioides Nees ex. Trin. These results were compared with those of P. bisulcatum Thumb. (C₃) and P. maximum Jacq. (C₄). Under all tested conditions, and even when the influence of leaf surface temperature on photosynthetic rates and CO₂ compensation points were measured, the biochemical and physiological behaviour of the C₃-C₄ intermediate was more similar to that of the C₃ plant than the C₄ species. The C₄ plant P. maximum, however, responded positively, mainly in terms of PEP-C activity and photosynthetic rate, to the regime of high light and temperature. The results presented indicate that in the C₃-C₄ Panicum grown in high light and temperature no direct relationships between a low CO₂ compesation point and superior growth are evident. It has still to be clarified why in nature a photosynthetic-photorespiratory pathway leading to an intermediate CO₂ compensation value has evolved in P. milioides.