ORCID Profile
0000-0002-2438-2352
Current Organisations
The University of Edinburgh
,
Royal Holloway University of London
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Publisher: Wiley
Date: 14-09-2011
Publisher: Wiley
Date: 14-08-2012
Publisher: Springer Science and Business Media LLC
Date: 18-03-2019
DOI: 10.1038/S41559-019-0839-9
Abstract: Organisms vary widely in size, from microbes weighing 0.1 pg to trees weighing thousands of megagrams - a 10
Publisher: Springer Science and Business Media LLC
Date: 15-05-2011
Publisher: The Royal Society
Date: 05-2023
DOI: 10.1098/RSOS.221023
Abstract: The eggs of avian obligate brood-parasitic species have multiple adaptations to deceive hosts and optimize development in host nests. While the structure and composition of the eggshell in all birds is essential for embryo growth and protection from external threats, parasitic eggs may face specific challenges such as high microbial loads, rapid laying and ejection by the host parents. We set out to assess whether eggshells of avian brood-parasitic species have either (i) specialized structural properties, to meet the demands of a brood-parasitic strategy or (ii) similar structural properties to eggs of their hosts, due to the similar nest environment. We measured the surface topography (roughness), wettability (how well surfaces repel water) and calcium content of eggshells of a phylogenetically and geographically erse range of brood-parasitic species (representing four of the seven independent lineages of avian brood-parasitic species), their hosts and close relatives of the parasites. These components of the eggshell structure have been demonstrated previously to influence such factors as the risk of microbial infection and overall shell strength. Within a phylogenetically controlled framework, we found no overall significant differences in eggshell roughness, wettability and calcium content between (i) parasitic and non-parasitic species, or (ii) parasitic species and their hosts. Both the wettability and calcium content of the eggs from brood-parasitic species were not more similar to those of their hosts' eggs than expected by chance. By contrast, the mean surface roughness of the eggs of brood-parasitic species was more similar to that of their hosts’ eggs than expected by chance, suggesting brood-parasitic species may have evolved to lay eggs that match the host nest environment for this trait. The lack of significant overall differences between parasitic and non-parasitic species, including hosts, in the traits we measured, suggests that phylogenetic signal, as well as general adaptations to the nest environment and for embryo development, outweigh any influence of a parasitic lifestyle on these eggshell properties.
Publisher: The Royal Society
Date: 03-07-2017
Abstract: Group living has been proposed to yield benefits that enhance fitness above the level that would be achieved through living as solitary in iduals. Dominance hierarchies occur commonly in these social assemblages, and result, by definition, in resources not being evenly distributed between group members. Determinants of rank within a dominance hierarchy can be associated with morphological characteristics, previous experience of the in idual, or personality traits such as exploration tendencies. The purpose of this study was to investigate whether greater exploration and positive responses to novel objects in homing pigeons ( Columba livia ) measured under laboratory conditions were associated with (i) greater initial exploration of the local area around the home loft during spontaneous exploration flights (SEF), (ii) faster and more efficient homing flights when released from further afield, and (iii) whether the traits of greater exploration and more positive responses to novel objects were more likely to be exhibited by the more dominant in iduals within the group. There was no relationship between laboratory-based novel object exploration and position within the dominance hierarchy. Pigeons that were neophobic under laboratory conditions did not explore the local area during SEF opportunities. When released from sites further from home, neophobic pigeons took longer routes to home compared to those birds that had not exhibited neophobic traits under laboratory conditions, and had spontaneously explored to a greater extent. The lack of exploration in the neophobic birds is likely to have resulted in the increased costs of homing following release: unfamiliarity with the landscape likely led to the greater distances travelled and less efficient routes taken. Birds that demonstrated a lack of neophobia were not the dominant in iduals inside the loft, and thus would have less access to resources such as food and potentially mates. However, a lack of neophobia makes the subordinate position possible, because subordinate birds that incur high travel costs would become calorie restricted and lose condition. Our results address emerging questions linking in idual variation in behaviour with energetics and fitness consequences. This article is part of the themed issue ‘Physiological determinants of social behaviour in animals’.
Publisher: Springer Science and Business Media LLC
Date: 07-2014
Publisher: The Company of Biologists
Date: 15-09-2009
DOI: 10.1242/JEB.034546
Abstract: Quantifying a relationship between heart rate (fH) and rate of oxygen consumption(V̇O2) allows the estimation of V̇O2from fH recordings in free-ranging birds. It has been proposed that this relationship may vary throughout an animal's annual cycle,due to changes in physiological status. Barnacle geese, Branta leucopsis, provide an ideal model to test this hypothesis, as they exhibit significant intra-annual variability in body mass, body composition and abdominal temperature, even in captivity. Heart rate data loggers were implanted in 14 captive barnacle geese, and at six points in the year the relationship between fH and V̇O2 was determined. The fH/V̇O2relationship was also determined in seven moulting wild barnacle geese to examine whether relationships from captive animals might be applicable to wild animals. In captive barnacle geese, the fH/V̇O2relationship was significantly different only between two out of the six periods when the relationship was determined (late September–early October and November). Accounting for changes in physiological parameters such as body mass, body composition and abdominal temperature did not eliminate this difference. The relationship between fH and V̇O2 obtained from wild geese was significantly different from all of the relationships derived from the captive geese, suggesting that it is not possible to apply calibrations from captive birds to wild geese. However, the similarity of the fH and V̇O2 relationship derived during moult in the captive geese to those during the remainder of the annual cycle implies it is not unreasonable to assume that the relationship between fH/V̇O2during moult in the wild geese is indicative of the relationship throughout the remainder of the annual cycle.
Publisher: The Royal Society
Date: 07-2023
Abstract: Many of the world's 10 000 bird species lay coloured or patterned eggs. The large ersity of eggshell patterning among birds, achieved through pigment, has been attributed to a few selective agents such as crypsis, thermoregulation, egg recognition, mate signalling, egg strength and protecting the embryo from UV. Pigmentation may influence the texture of eggshells, which in turn may be important for dealing with water and microbes. We measured surface roughness ( S a , nm), surface skewness ( S sk ) and surface kurtosis ( S ku ), which describe different aspects of surface texture, across 204 bird species with maculated (patterned) eggs and 166 species with immaculate (non-patterned) eggs. Using phylogenetically controlled analyses, we tested whether maculated eggshells have different surface topography between the foreground colour and background colour, and between the background colour of maculated eggshells and the surface of immaculate eggshells. Secondly, we determined to what extent variation in eggshell pigmentation of the foreground and background colour is determined by phylogenetic relatedness, and whether certain life-history traits are important predictors of eggshell surface structure. We show that the surface of maculated eggs consists of a rougher foreground pigment compared to the background pigment across 71% of the 204 bird species (54 families) investigated. Species that lay immaculate eggs showed no difference in surface roughness, kurtosis or skewness compared to background pigment of maculated eggs. The difference in eggshell surface roughness between foreground and background pigmentation was greater among species that occupied dense habitats, such as forests with closed canopies, compared to those that nest in open and semi-open habitats (e.g. cities, deserts, grasslands, open shrubland and seashores). Among maculated eggs, foreground texture was correlated with habitat, parental care, diet, nest location, avian group and nest type, while background texture was correlated with clutch size, annual temperature, development mode and annual precipitation. Surface roughness among immaculate eggs was greatest for herbivores, and species that have larger clutch sizes. Together, this suggests that multiple life-history traits have influenced the evolution of eggshell surface textures in modern birds.
Publisher: The Royal Society
Date: 16-06-2021
Abstract: Embryo survival in birds depends on a controlled transfer of water vapour and respiratory gases through the eggshell, and this exchange is critically sensitive to the surrounding physical environment. As birds breed in most terrestrial habitats worldwide, we proposed that variation in eggshell conductance has evolved to optimize embryonic development under different breeding conditions. This is the first study to take a broad-scale macro-ecological view of avian eggshell conductance, encompassing all key avian taxonomic groups, to assess how life history and climate influence the evolution of this trait. Using whole eggs spanning a wide phylogenetic ersity of birds, we determine that body mass, temperature seasonality and whether both parents attend the nest are the main determinants of eggshell conductance. Birds breeding at high latitudes, where seasonal temperature fluctuations are greatest, will benefit from lower eggshell conductance to combat temporary periods of suspended embryo growth and prevent dehydration during prolonged incubation. The nest microclimate is more consistent in species where parents take turns incubating their clutch, resulting in lower eggshell conductance. This study highlights the remarkable functional qualities of eggshells and their importance for embryo survival in extreme climates.
Publisher: Public Library of Science (PLoS)
Date: 09-08-2010
Publisher: The Royal Society
Date: 16-11-2011
Abstract: Hypertrophy of the flight muscles is regularly observed in birds prior to long-distance migrations. We tested the hypothesis that a large migratory bird would increase flight behaviour prior to migration, in order to cause hypertrophy of the flight muscles, and upregulate key components of the aerobic metabolic pathways. Implantable data loggers were used to record year-round heart rate in six wild barnacle geese ( Branta leucopsis ), and the amount of time spent in flight each day was identified. Time in flight per day did not significantly increase prior to either the spring or the autumn migration, both between time periods prior to migration (5, 10 and 15 days), or when compared with a control period of low activity during winter. The lack of significant increase in flight prior to migration suggests that approximately 22 min per day is sufficient to maintain the flight muscles in condition for prolonged long-distance flight. This apparent lack of a requirement for increased flight activity prior to migration may be attributable to pre-migratory mass gains in the geese increasing workload during short flights, potentially prompting hypertrophy of the flight muscles.
Publisher: The Company of Biologists
Date: 15-09-2014
DOI: 10.1242/JEB.103291
Abstract: Carefully controlled gas exchange across the eggshell is essential for the development of the avian embryo. Water vapour conductance (GH2O) across the shell, typically measured as mass loss during incubation, has been demonstrated to optimally ensure the healthy development of the embryo while avoiding desiccation. Accordingly, eggs exposed to sub-optimal gas exchange have reduced hatching success. We tested the association between eggshell GH2O and putative life-history correlates of adult birds, ecological nest parameters and physical characteristics of the egg itself to investigate how variation in GH2O has evolved to maintain optimal water loss across a erse set of nest environments. We measured gas exchange through eggshell fragments in 151 British breeding bird species and fitted phylogenetically controlled, general linear models to test the relationship between GH2O and potential predictor parameters of each species. Of our 17 life-history traits, only two were retained in the final model: wet-incubating parent and nest type. Eggs of species where the parent habitually returned to the nest with wet plumage had significantly higher GH2O than those of parents that returned to the nest with dry plumage. Eggs of species nesting in ground burrows, cliffs and arboreal cups had significantly higher GH2O than those of species nesting on the ground in open nests or cups, in tree cavities and in shallow arboreal nests. Phylogenetic signal (measured as Pagel's λ) was intermediate in magnitude, suggesting that differences observed in the GH2O are dependent upon a combination of shared ancestry and species-specific life history and ecological traits. Although these data are correlational by nature, they are consistent with the hypothesis that parents constrained to return to the nest with wet plumage will increase the humidity of the nest environment, and the eggs of these species have evolved a higher GH2O to overcome this constraint and still achieve optimal water loss during incubation. We also suggest that eggs laid in cup nests and burrows may require a higher GH2O to overcome the increased humidity as a result from the confined nest microclimate lacking air movements through the nest. Taken together, these comparative data imply that species-specific levels of gas exchange across avian eggshells are variable and evolve in response to ecological and physical variation resulting from parental and nesting behaviours.
Publisher: American Geophysical Union (AGU)
Date: 02-2006
DOI: 10.1029/2005GC001060
Publisher: The Company of Biologists
Date: 2012
DOI: 10.1242/JEB.076554
Abstract: Animal-borne logging or telemetry devices are widely used for the measurements of physiological and movement data from free-living animals. For such measurements to be relevant, however, it is essential that the devices themselves do not affect the data of interest. A recent meta-analysis (Barron et al. 2010 Methods Ecol Evol. 1:180-187) reported an overall negative effect of these devices on the birds that bear them, i.e. on nesting productivity, clutch size, nest initiation date, offspring quality, body condition, flying ability, foraging behaviours, energy expenditure or survival rate. Method of attachment (Harness, Collar, Glue, Anchor, Implant, Breast-mounted, Tailmount) had no influence on the strength of these effects but anchored and implanted transmitters had the highest reported rates of device-induced mortality. Furthermore, external devices, but not internal devices, caused an increase in 'device-induced behaviour' (comfort behaviours such as preening, fluffing and stretching, and unrest activities including unquantifiable 'active' behaviours). These findings suggest that, with the exception of device-induced behaviour, external attachment is preferable to implantation. In the present study we undertake a meta-analysis of 183 estimates of device impact from 39 studies of 36 species of bird designed to explicitly compare the effects of externally-attached and surgically-implanted devices on a range of traits, including condition, energy expenditure, and reproduction. In contrast to Barron et al., we demonstrate that externally-attached devices have a consistent detrimental effect (i.e., negative influences on body condition, reproduction, metabolism, and survival), whereas implanted devices have no consistent effect. We also show that the magnitude of the negative effect of externally attached devices decreases with time. We therefore conclude that device implantation is preferable to external attachment, providing that the risk of mortality associated with the anaesthesia and surgery required for implantation can be mitigated. We recommend that studies employing external devices use devices that can be borne for long periods, and, wherever possible, deploy devices in advance of the time period of interest.
Publisher: University of Chicago Press
Date: 09-2006
DOI: 10.1086/505994
Abstract: Respirometry is a standard technique in comparative physiology laboratories, with measurements of rates of O(2) consumption and CO(2) production available for hundreds of species. A common recommendation when carrying out respirometry is that water vapor be removed from the air stream before entering the analyzer. Often, this is accomplished with the use of chemical desiccants, such as Drierite. However, here we show that Drierite has an affinity for CO(2) when new and completely anhydrous, and therefore it has an adverse effect on the washout characteristics of this gas. Exposing the Drierite to room air reduces this CO(2) affinity, and a 2-min exposure at 20 degrees Celsius and 50% relative humidity is sufficient to reduce the 99% washout time by almost a factor of 4, at the cost of only a 5% reduction in water vapor capacity. When Drierite is exhausted and then recharged according to the manufacturer's instructions, the CO(2) affinity is further reduced, and washout times are less than 60% greater than when no desiccant is used.
Publisher: The Royal Society
Date: 11-2018
Abstract: Waterfowl undergo an annual simultaneous flight-feather moult that renders them flightless for the duration of the regrowth of the flight feathers. In the wild, this period of flightlessness could restrict the capacity of moulting birds to forage and escape predation. Selection might therefore favour a short moult, but feather growth is constrained and presumably energetically demanding. We therefore tested the hypothesis that for birds that undergo a simultaneous flight-feather moult, this would be the period in the annual cycle with the highest minimum daily heart rates, reflecting these increased energetic demands. Implantable heart rate data loggers were used to record year-round heart rate in six wild barnacle geese ( Branta leucopsis ), a species that undergoes a simultaneous flight-feather moult. The mean minimum daily heart rate was calculated for each in idual bird over an 11-month period, and the annual cycle was ided into seasons based on the life-history of the birds. Mean minimum daily heart rate varied significantly between seasons and was significantly elevated during wing moult, to 200 ± 32 beats min −1 , compared to all other seasons of the annual cycle, including both the spring and autumn migrations. The increase in minimum daily heart rate during moult is likely due to feather synthesis, thermoregulation and the reallocation of minerals and protein.
Publisher: Wiley
Date: 30-06-2011
Publisher: Oxford University Press (OUP)
Date: 03-05-2012
Publisher: Wiley
Date: 29-07-2014
Publisher: The Royal Society
Date: 08-2020
Abstract: Dominance hierarchies confer benefits to group members by decreasing the incidences of physical conflict, but may result in certain lower ranked in iduals consistently missing out on access to resources. Here, we report a linear dominance hierarchy remaining stable over time in a closed population of birds. We show that this stability can be disrupted, however, by the artificial mass loading of birds that typically comprise the bottom 50% of the hierarchy. Mass loading causes these low-ranked birds to immediately become more aggressive and rise-up the dominance hierarchy however, this effect was only evident in males and was absent in females. Removal of the artificial mass causes the hierarchy to return to its previous structure. This interruption of a stable hierarchy implies a strong direct link between body mass and social behaviour and suggests that an in idual's personality can be altered by the artificial manipulation of body mass.
Publisher: Wiley
Date: 04-05-2021
Abstract: Climate affects all aspects of biology. Physiological traits play a key role in mediating these effects, because they define the fundamental niche of each organism. Climate change is likely to shift environmental conditions away from physiological optima. The consequences for species are significant: they must alter their physiology through plasticity or adaptation, move, or decline to extinction. The ability to understand and predict such organismal responses to global change is, however, only as good as the geographical coverage of the data on which these predictions are based. Geographical biases in the state of physiological knowledge have been identified, but it has not been determined if these geographical biases are likely to limit our capacity to predict the outcomes of global change. We show that current knowledge of physiological traits is representative of only a limited range of the climates in which terrestrial animals will be required to operate, because data for animals from only a limited range of global climates have been incorporated in existing compilations. We conclude that geographical bias in existing datasets limits our capacity to predict organismal responses in the vast areas of the planet that are unstudied, and that this geographical bias is a much greater source of uncertainty than the difference between the current climate and the projected future climate. Addressing this bias is urgent to understand where impacts will be most profound, and where the need for intervention is most pressing. A free Plain Language Summary can be found within the Supporting Information of this article.
Publisher: Wiley
Date: 08-11-2021
Abstract: Animal‐borne logging devices are now commonly used to record and monitor the movements, physiology and behaviours of free‐living animals. It is imperative that the impacts these devices have on the animals themselves are minimised. One important consideration is the interaction between the body mass of the animal and the mass of the device. Using captive homing pigeons, we demonstrate that birds lose the equivalent amount of body mass compared to that of the logging device attached. With our experiments, we calculated that the compensatory mass loss because of the logging device equates to a total loss of 1,140 kJ of energy to the bird, over the 25‐day period. This equates to 32% per day of their total daily energy budget. We suggest that practitioners of biologging give due consideration to the possibility of a device‐induced decrease in body mass when making decisions regarding device size, and when considering the period of the time of the year at which devices are attached. It appears, based on the results of the present study, that device attachment is likely to be most disruptive during periods of regulated mass change, especially when periods of mass gain precede periods in which stored energy reserves are extensively utilised. These findings have significant consequences for anyone using biologging technology on both wild and captive volant animals. Further studies utilising captive birds are now needed to fully understand how context‐ and species‐dependent physiological responses to externally attached devices are.
Publisher: Wiley
Date: 20-06-2012
Publisher: Wiley
Date: 25-01-2017
DOI: 10.1111/IBI.12447
Publisher: Wiley
Date: 14-05-2018
Publisher: Frontiers Media SA
Date: 25-07-2017
Publisher: The Royal Society
Date: 10-2021
Abstract: Complex and at times extreme environments have pushed many bird species to develop unique eggshell surface properties to protect the embryo from external threats. Because microbes are usually transmitted into eggs by moisture, some species have evolved hydrophobic shell surfaces that resist water absorption, while also regulating heat loss and the exchange of gases. Here, we investigate the relationship between the wettability of eggshells from 441 bird species and their life-history traits. We measured the initial contact angle between sessile water droplets and the shell surface, and how far the droplet spread. Using phylogenetic comparative methods, we show that body mass, annual temperature and eggshell maculation primarily explained variance in water contact angle across eggshells. Species nesting in warm climates were more likely to exhibit highly hydrophobic eggshells than those nesting in cold climates, potentially to reduce microbial colonization. In non-passerines, immaculate eggs were found to have more hydrophobic surfaces than maculate eggshells. Droplets spread more quickly on eggshells incubated in open nests compared to domed nests, likely to decrease heat transfer from the egg. Here, we identify clear adaptations of eggshell wettability across a erse range of nesting environments, driven by the need to retain heat and prevent microbial adhesion.
Publisher: CSIRO Publishing
Date: 2011
DOI: 10.1071/RD10138
Abstract: The avian embryo resorbs most of the calcium for bone formation from the calcite eggshell but the exact mechanisms of the resorption are unknown. The present study tested whether this process results in variable fractionation of the oxygen and carbon isotopes in shell calcium carbonate, which could provide a detailed insight into the temporal and spatial use of the eggshell by the developing embryo. Despite the uncertainty regarding changes in stable isotope composition of the eggshell across developmental stages or regions of the shell, eggshells are a popular resource for the analysis of historic and extant trophic relationships. To clarify how the stable isotope composition varies with embryonic development, the δ13C and δ18O content of the carbonate fraction in shells of black-headed gull (Larus ridibundus) eggs were s led at four different stages of embryonic development and at five eggshell regions. No consistent relationship between the stable isotope composition of the eggshell and embryonic development, shell region or maculation was observed, although shell thickness decreased with development in all shell regions. By contrast, in idual eggs differed significantly in isotope composition. These results establish that eggshells can be used to investigate a species’ carbon and oxygen sources, regardless of the egg’s developmental stage.
Publisher: The Royal Society
Date: 26-09-2016
Abstract: While some migratory birds perform non-stop flights of over 11 000 km, many species only spend around 15% of the day in flight during migration, posing a question as to why flight times for many species are so short. Here, we test the idea that hyperthermia might constrain flight duration (FD) in a short-distance migrant using remote biologging technology to measure heart rate, hydrostatic pressure and body temperature in 19 migrating eider ducks ( Somateria mollissima ), a short-distance migrant. Our results reveal a stop-and-go migration strategy where migratory flights were frequent (14 flights day −1 ) and short (15.7 min), together with the fact that body temperature increases by 1°C, on average, during such flights, which equates to a rate of heat storage index (HSI) of 4°C h −1 . Furthermore, we could not find any evidence that short flights were limited by heart rate, together with the fact that the numerous stops could not be explained by the need to feed, as the frequency of es and the time spent feeding were comparatively small during the migratory period. We thus conclude that hyperthermia appears to be the predominant determinant of the observed migration strategy, and suggest that such a physiological limitation to FD may also occur in other species. This article is part of the themed issue ‘Moving in a moving medium: new perspectives on flight’.
Publisher: Wiley
Date: 09-2017
DOI: 10.1111/JFB.13357
Abstract: The anabantoids are a group of c. 137 species of air-breathing freshwater fishes found in Africa and southern Asia. All anabantoids have a pair of suprabranchial chambers that each house an air-breathing organ known as the labyrinth apparatus: a complex bony structure lined with thin, highly vascularised respiratory epithelium. The labyrinth apparatus allows anabantoids to extract oxygen from air and is a morpho-physiological innovation that has had a dramatic influence on the behaviour of these fishes. Air-breathing influences a wide range of anabantoid behaviours, including territorial displays, courtship and breeding and parental care and also equips these fishes to persist in hypoxic and polluted water. These traits also make anabantoids successful invaders of novel habitats, a global problem compounded by their popularity in the aquarium trade. By reviewing the functionality and evolution of air breathing in anabantoids, this review aims to examine the role of the labyrinth apparatus in modulating behaviour within this group. The anabantoids are a fascinating group and have often been cited as a model organism due to the stereotypical and easily identifiable behaviours that they adopt during social interactions. They also provide a unique opportunity to further our understanding about how fishes adapt their behaviour in response to an extreme environment, whilst limited by their own physiological constraints.
Publisher: Wiley
Date: 21-05-2014
DOI: 10.1111/JZO.12144
Publisher: Wiley
Date: 12-02-2016
DOI: 10.1002/ECE3.1960
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.CBPA.2012.11.012
Abstract: Air-breathing fish of the Anabantoidei group meet their metabolic requirements for oxygen through both aerial and aquatic gas exchange. Siamese fighting fish Betta splendens are anabantoids that frequently engage in aggressive male-male interactions which cause significant increases in metabolic rate and oxygen requirements. These interactions involve opercular flaring behaviour that is thought to limit aquatic oxygen uptake, and combines with the increase in metabolic rate to cause an increase in air-breathing behaviour. Air-breathing events interrupt display behaviour and increase risk of predation, raising the question of how Siamese fighting fish manage their oxygen requirements during agonistic encounters. Using open-flow respirometry, we measured rate of oxygen consumption in displaying fish to determine if males increase oxygen uptake per breath to minimise visits to the surface, or increase their reliance on aquatic oxygen uptake. We found that the increased oxygen requirements of Siamese fighting fish during display behaviour were met by increased oxygen uptake from the air with no significant changes in aquatic oxygen uptake. The increased aerial oxygen uptake was achieved almost entirely by an increase in air-breathing frequency. We conclude that limitations imposed by the reduced gill surface area of air-breathing fish restrict the ability of Siamese fighting fish to increase aquatic uptake, and limitations of the air-breathing organ of anabantoids largely restrict their capacity to increase oxygen uptake per breath. The resulting need to increase surfacing frequency during metabolically demanding agonistic encounters has presumably contributed to the evolution of the stereotyped surfacing behaviour seen during male-male interactions, during which one of the fish will lead the other to the surface, and each will take a breath of air.
Publisher: University of Chicago Press
Date: 11-2010
DOI: 10.1086/656287
Abstract: Typically, eggshell water vapor conductance is measured on whole eggs, freshly collected at the commencement of a study. At times, however, it may not be possible to obtain whole fresh eggs but rather egg fragments or previously blown eggs. Here we evaluate and describe in detail a technique for modern laboratory analysis of eggshell conductance that uses fragments from fresh and museum eggs to determine eggshell water vapor conductance. We used fresh unincubated eggs of domesticated chickens (Gallus gallus domesticus), ducks (Anas platyrhynchos domesticus), and guinea fowl (Numida meleagris) to investigate the reliability, validity, and repeatability of the technique. To assess the suitability of museum s les, museum and freshly collected black-headed gull eggs (Larus ridibundus) were used. Fragments were cut out of the eggshell from the blunt end (B), equator (E), and pointy end (P). Eggshell fragments were glued to the top of a 0.25-mL micro test tube (Eppendorf) filled with 200 μL of distilled water and placed in a desiccator at 25°C. Eppendorfs were weighed three times at 24-h intervals, and mass loss was assumed to be a result of water evaporation. We report the following results: (1) mass loss between weighing sessions was highly repeatable and consistent in all species (2) the majority of intraspecific variability in eggshell water vapor conductance between different eggs of the same species was explained through the differences in water vapor conductance between the three eggshell parts of the same egg (B, E, and P) (3) the technique was sensitive enough to detect significant differences between the three domestic species (4) there was no overall significant difference between water vapor conductance of museum and fresh black-headed gull eggs (5) there was no significant difference in water vapor conductance for egg fragments taken from the same egg both between different trials and within the same trial. We conclude, therefore, that this technique is an effective way of measuring interspecific water vapor conductance from eggshell fragments and that museum eggs are a suitable resource for such work.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Steven Portugal.