Foraging behaviour at carcasses in an Asian vulture assemblage: towards a good restaurant guide

2015 ◽  
Vol 26 (3) ◽  
pp. 263-272 ◽  
Author(s):  
SABINE M. HILLE ◽  
FRÄNZI KORNER-NIEVERGELT ◽  
MAARTEN BLEEKER ◽  
NIGEL J. COLLAR
Keyword(s):  
Spatial Distribution ◽  
Body Size ◽  
Foraging Behaviour ◽  
Size Range ◽  
Individual Species ◽  
Interspecific Aggression ◽  
Critically Endangered Species ◽  
Size Number ◽  
Dominance Behaviour ◽  
Number Of Individuals

SummaryVulture populations are declining steeply worldwide. Vulture ‘restaurants’ or feeding stations are a tool for maintaining and monitoring numbers, but individual species may be disadvantaged by the effects of carcass distribution, carcass size and interspecific aggression. To test the degree to which restaurants give opportunities for each species to access the food provided, we studied behaviour and morphology in three Critically Endangered species of vulture in Cambodia: the gregariously breeding and feeding White-rumped Vulture Gyps bengalensis and Slender-billed Vulture G. tenuirostris, and the solitary Red-headed Vulture Sarcogyps calvus. We video-recorded attendance time, attendance order and dominance behaviour at different-sized carcasses. Interspecific aggression at carcasses was least frequently shown by the ‘small’ White-rumped Vulture. The relatively ‘large’ Slender-billed and ‘medium’ Red-headed Vultures showed aggression more regularly and at similar levels. However, the latter avoids conflict by waiting until Gyps vultures are no longer crowding at the carcass, although its arrival at carcasses was correlated with total number of vultures present. While more numerous than Red-headed, the two Gyps vultures are more dependent on large carcasses, which increases their vulnerability to further declines in wild large ungulate species. Body size, number of individuals, hunger levels and carcass size and availability all influence carcass attendance behaviour. An increase in the number and spatial distribution of restaurants as well as of carcass size range could boost numbers of all vulture species.

Age structure and body size of a critically endangered species, Acanthodactylus harranensis (Squamata: Lacertidae) and its demography

2019 ◽  
Vol 69 (4) ◽  
pp. 421-431
Author(s):  
Nurettin Beşer ◽  
Çetin Ilgaz ◽  
Yusuf Kumlutaş ◽  
Aziz Avcı ◽  
Kamil Candan ◽  
...  
Keyword(s):  
Body Size ◽  
Endangered Species ◽  
Age Structure ◽  
Critically Endangered ◽  
Age Group ◽  
Lizard Species ◽  
Critically Endangered Species ◽  
Area Of Occupancy ◽  
The Mean ◽  
Number Of Individuals

Abstract Within reptiles, lizards cover less area across the globe than snakes do. One out of every seven known species of lizards in the world is found only in its type locality. Acanthodactylus harranensis Baran, Kumlutaş, Lanza, Sindaco, Ilgaz, Avcı & Crucitti, 2005, is one of these species. It is an endemic lizard species in Turkey with a very small area of occupancy and is listed in the critically endangered category (CR) by the IUCN. Here we document the age structure and body size of A. harranensis using skeletochronological methods for the first time and aim to point out current problems and contribute to an understanding of its demography. The mean age of males was found to be significantly higher than that of females. The maximum life span was 10 years in males while it was 9 years in females. The 8-year-old age group contained a higher number of individuals than any other age group. The mean snout-vent length of specimens was not significantly different between the sexes. As in many other lizards, A. harranensis exhibits a low-level male-biased sexual dimorphism. Acanthodactylus harranensis also displayed a considerably bigger body size than other studied lacertids from Şanlıurfa province. The data presented in this study may contribute to future conservation efforts for this endangered species.

scholarly journals Foraging behaviour and performance of steers from two local breeds (Asturian Valley and Asturian Mountain) grazing in Cantabrian (N Spain) summer pastures

2019 ◽  
Vol 17 (1) ◽  
pp. e0601
Author(s):  
Alicia Román-Trufero ◽  
Antonio Martínez ◽  
Luis M. M. Ferreira ◽  
Valentín García-Prieto ◽  
Rocío Rosa-García ◽  
...  
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Diet Composition ◽  
Foraging Behaviour ◽  
Meat Production ◽  
Market Demand ◽  
Nutrient Requirements ◽  
Northern Spain ◽  
Sward Height ◽  
And Performance

Steer meat production in northern Spain is deficient to attend market demand. This research aimed to compare the foraging behaviour and production of yearling steers from two local breeds differing in body weight (BW), Asturian Valley (AV, 372 kg) and Asturian Mountain (AM, 307 kg), grazing in summer pastures consisting of 70% grassland and 30% heathland. Bodyweight gains from a total of 42 steers were recorded during four grazing seasons (from June to October). In two years, in July and September, plant community selection and diet composition were estimated by direct observation and using faecal markers, respectively. Grazing time increased from July to September (488 vs. 557 min/day; p<0.001) as sward height in the grassland decreased. Although AV steers grazed proportionally for longer on herbaceous pastures than AM steers (81.3 vs. 73.3%; p<0.05), no differences between breeds were found in diet composition. AM steers showed greater mean daily BW gains than AV steers (252 vs. 133 g/day; p<0.01). From June to August, steers from both breeds gained BW (487 vs. 360 g/day for AM and AV, respectively; p<0.01), but thereafter BW gains decreased (120 vs. –12 g/day for AM and AV, respectively; p<0.05), because of reduced availability of grassland herbage. Yearling steers from AM breed seem to be better suited to mountain conditions than those from AV breed, probably because of their smaller body size and lower total nutrient requirements for maintenance.

scholarly journals Determinants of Spatial Distribution in a Bee Community: Nesting Resources, Flower Resources, and Body Size

PLoS ONE ◽  
2014 ◽  
Vol 9 (5) ◽  
pp. e97255 ◽  
Author(s):  
Anna Torné-Noguera ◽  
Anselm Rodrigo ◽  
Xavier Arnan ◽  
Sergio Osorio ◽  
Helena Barril-Graells ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Body Size ◽  
Nesting Resources ◽  
Flower Resources ◽  
Bee Community

Challenges and advances in the study of pterosaur flight

2015 ◽  
Vol 93 (12) ◽  
pp. 945-959 ◽  
Author(s):  
K.M. Middleton ◽  
L.T. English
Keyword(s):  
Body Size ◽  
Size Range ◽  
Flapping Flight ◽  
Flight Mechanics ◽  
Wing Membrane ◽  
Membrane Function ◽  
Aerodynamic Modeling ◽  
History Of ◽  
Bone Loading

Pterosaurs have fascinated scientists and nonscientists alike for over 200 years, as one of the three known clades of vertebrates to have evolved flapping flight. The smallest pterosaurs were comparable in size to the smallest extant birds and bats, but the largest pterosaurs were vastly larger than any extant flier. This immense size range, coupled with poor preservation and adaptations for flight unknown in extant vertebrates, have made interpretations of pterosaur flight problematic and often contentious. Here we review the anatomical, evolutionary, and phylogenetic history of pterosaurs, as well as the views, perspectives, and biases regarding their interpretation. In recent years, three areas of pterosaur biology have faced challenges and made advances: structure of the wing membrane, function of the pteroid, body size and mass estimates, as well as flight mechanics and aerodynamics. Comparative anatomical and fossil study, simulated bone loading, and aerodynamic modeling have all proved successful in furthering our understanding of pterosaur flight. We agree with previous authors that pterosaurs should be studied as pterosaurs, a diverse but phylogenetically, anatomically, and mechanically constrained clade that can offer new insights into the diversity of vertebrate flight.

scholarly journals Late Pleistocene glacial–interglacial shell-size–isotope variability in planktonic foraminifera as a function of local hydrography

2015 ◽  
Vol 12 (15) ◽  
pp. 4781-4807 ◽  
Author(s):  
B. Metcalfe ◽  
W. Feldmeijer ◽  
M. de Vringer-Picon ◽  
G.-J. A. Brummer ◽  
F. J. C. Peeters ◽  
...  
Keyword(s):  
Size Range ◽  
North Atlantic Ocean ◽  
Life Stage ◽  
Planktonic Foraminifera ◽  
Isotope Analysis ◽  
Past Research ◽  
Individual Species ◽  
Shell Size ◽  
Size Fractions ◽  
Water Column Stratification

Abstract. So-called "vital effects" are a collective term for a suite of physiologically and metabolically induced variability in oxygen (δ18O) and carbon (δ13C) isotope ratios of planktonic foraminifer shells that hamper precise quantitative reconstruction of past ocean parameters. Correction for potential isotopic offsets from equilibrium or the expected value is paramount, as too is the ability to define a comparable life stage for each species that allows for direct comparison. Past research has focused upon finding a specific size range for individual species in lieu of other identifiable features, thus allowing ocean parameters from a particular constant (i.e. a specific depth or season) to be reconstructed. Single-shell isotope analysis of fossil shells from a mid-latitude North Atlantic Ocean piston core covering Termination III (200 to 250 ka) highlight the advantage of using a dynamic size range, i.e. utilising measurements from multiple narrow sieve size fractions spanning a large range of total body sizes, in studies of palaeoclimate. Using this methodology, we show that isotopic offsets between specimens in successive size fractions of Globorotalia inflata and Globorotalia truncatulinoides are not constant over time, contrary to previous findings. For δ18O in smaller-sized globorotalids (212–250 μm) it is suggested that the offset from other size fractions may reflect a shallower habitat in an early ontogenetic stage. A reduction in the difference between small and large specimens of G. inflata between insolation minima and maxima is interpreted to relate to a prolonged period of reduced water column stratification. For the shallow-dwelling species Globigerina bulloides, no size–isotope difference between size fractions is observed, and the variability in the oxygen isotopic values is shown to correlate well with the seasonal insolation patterns. As such, patterns in oxygen isotope variability of fossil populations may be used to reconstruct past seasonality changes.

Reproductive biology of the false coral snake Oxyrhopus guibei (Colubridae) from southeastern Brazil

2002 ◽  
Vol 23 (4) ◽  
pp. 495-504 ◽  
Author(s):  
Otavio Marques ◽  
Lígia Pizzatto
Keyword(s):  
Body Size ◽  
Reproductive Biology ◽  
Rainy Season ◽  
Reproductive Activity ◽  
Climatic Conditions ◽  
Southeastern Brazil ◽  
Coral Snake ◽  
Males And Females ◽  
Reproductive Cycles ◽  
Number Of Individuals

AbstractThe reproductive biology of the false coral snake, Oxyrhopus guibei, was studied through dissection of 496 specimens, combined with observations on captive individuals. Males mature with smaller body size than females, females attain much larger body size, and male-male combat is not expected. Clutch size ranged from 3 to 20, and was correlated with female length. Reproductive cycles in both males and females seem to be continuous, with vitellogenesis and spermatogenesis occurring throughout the year. Reproductive activity in both sexes decreased at the end of the rainy season possibly due to previous intense reproductive activity in more favorable climatic conditions. The smaller number of individuals collected at the end of the rainy season apparently occurs due to the decrease of reproductive activity of this snake.

Size-related foraging behaviour of the leaf-cutting ant Atta colombica

1991 ◽  
Vol 69 (6) ◽  
pp. 1530-1533 ◽  
Author(s):  
Dave Shutler ◽  
Adele Mullie
Keyword(s):  
Body Size ◽  
Leaf Litter ◽  
Tree Species ◽  
Foraging Behaviour ◽  
Foraging Theory ◽  
Costa Rican ◽  
Leaf Cutting ◽  
Foraging Trail ◽  
Atta Colombica ◽  
Load Mass

In a Costa Rican forest adjacent to cattle pasture, larger individuals of the leaf-cutting ant Atta colombica carried heavier loads and foraged farther from the colony, as predicted by foraging theory. Counter to foraging theory, individual ants did not increase their load mass if they foraged farther from the colony. However, the colony avoided this apparent inefficiency by sending larger ants to more distant trees. The colony harvested simultaneously from several individuals of the same tree species, even though distant trees were twice as far from the colony as nearby trees. The reasons for this behaviour require further investigation. In a wide foraging trail, larger ants travelled faster than their smaller counterparts. In addition, ant velocity was reduced when loads were experimentally supplemented, and increased when loads were experimentally reduced. Ants using narrow trails in the leaf litter may all be constrained to travel at the same speed, irrespective of load or body size, simply because they get in each other's way.

Characterization of Particle Size, Number, and Mass Emissions From a Diesel Powered Generator

2006 ◽  
Author(s):  
Imad A. Khalek
Keyword(s):  
Particle Size ◽  
Solid Particle ◽  
Particle Distribution ◽  
Size Range ◽  
Number Concentration ◽  
Solid Particles ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Engine Operation ◽  
Size Number

Total (volatile plus solid) and solid particle size, number, and mass emitted from a 3.8 kW diesel powered generator were characterized using a Scanning Mobility Particle Sizer (SMPS) that measures the size distribution of particles, and a catalytic stripper that facilitates the measurement of solid particles. The engine was operated at a constant speed for six steady-state engine operations ranging from idle to rated power. The solid particle size distributions were mainly monomodal lognormal distributions in nature reflecting a typical soot agglomerate size distribution with a number mean diameter in the size range from 98 nm to 37 nm as the load decreases from high to low. At idle, M6, however, the solid particle distribution was bimodal in nature with a high number of solid nanoparticles in the sub-20 nm size range. It is likely that these solid particles nucleated later in the combustion process from metallic ash typically present in the lube oil. The total particle size distributions exhibited a bimodal structure only at light load, M5, engine operation, where a high number of volatile nanoparticles were observed. The rest of the operating conditions exhibited monomodal distributions although the nature of the particles was vastly different. For the medium load modes, M2, M3, and M4, the particles were mainly solid particles. For the rated power, M1, and idle, M6, modes of engine operation, significant number of volatile particles grew to a size nearing that of soot particles making the distribution monomodal, similar to that of a solid particle distribution. This shows that monomodal distributions are not necessarily solid particle but they can be strongly dominated with volatile particles if significant particle growth takes place like the case at M1, and M6. The total number and mass concentration were extremely high at engine rated power. The number concentration exceeded 1.2 billion particles per cubic centimeter and the mass exceeded 750 milligrams per cubic meter. The number concentration is more than five orders of magnitude higher than a typical ambient level concentration, and the mass concentration is more than four orders of magnitude higher. It is important to indicate, however, that if the engine power rating is lowered by 35 percent from its designated level, both particle mass and number emissions will be reduced by two orders of magnitude. By measuring total and solid particle size and number concentration of particles, one can calculate other metrics such as surface area and mass to provide detail information about particle emissions. Such information can serve as an important database where all metrics of particle emissions are captured.

A new skink fauna from Caribbean islands (Squamata, Mabuyidae, Mabuyinae)

Zootaxa ◽  
2012 ◽  
Vol 3288 (1) ◽  
pp. 1 ◽  
Author(s):  
S. BLAIR HEDGES ◽  
CAITLIN E. CONN
Keyword(s):  
Body Size ◽  
South America ◽  
Reproductive Traits ◽  
Morphological Characters ◽  
Critically Endangered ◽  
Glacial Cycles ◽  
Critically Endangered Species ◽  
Caribbean Islands ◽  
Island Species ◽  
Degree Of Convergence

Neotropical skinks are unique among lizards and other vertebrates in their degree of convergence, in reproductive traits,with eutherian mammals. They have also been famously difficult to classify into species, largely because of a conservativebody plan and paucity of conventional diagnostic characters. Currently there are 26 recognized species, six of which occuronly on Caribbean islands. All are placed in a single genus, Mabuya. We conducted a systematic revision of Neotropicalskinks using both conventional and unconventional morphological characters, supplemented by DNA sequence analyses.We define 61 species grouped into 16 clades, recognized here as genera. They include three available generic names(Copeoglossum, Mabuya, and Spondylurus) and 13 new genera: Alinea gen. nov., Aspronema gen. nov., Brasiliscincusgen. nov., Capitellum gen. nov., Exila gen. nov., Manciola gen. nov., Maracaiba gen. nov., Marisora gen. nov., Noto-mabuya gen. nov., Orosaura gen. nov., Panopa gen. nov., Psychosaura gen. nov., and Varzea gen. nov. These 16 generaof skinks form a monophyletic group and are placed in the Subfamily Mabuyinae of the skink Family Mabuyidae. Sixother skink families are recognized: Acontidae, Egerniidae, Eugongylidae, Lygosomidae, Scincidae, and Sphenomorphi-dae. We describe three new subfamilies of Mabuyidae: Chioniniinae subfam. nov., Dasiinae subfam. nov., and Trachyl-epidinae subfam. nov. We describe 24 new species of mabuyines: Capitellum mariagalantae sp. nov., Capitellumparvicruzae sp. nov., Copeoglossum aurae sp. nov., Copeoglossum margaritae sp. nov., Copeoglossum redondae sp.nov., Mabuya cochonae sp. nov., Mabuya desiradae sp. nov., Mabuya grandisterrae sp. nov., Mabuya guadeloupae sp.nov., Mabuya hispaniolae sp. nov., Mabuya montserratae sp. nov., Marisora aurulae sp. nov., Marisora magnacornaesp. nov., Marisora roatanae sp. nov., Spondylurus anegadae sp. nov., Spondylurus culebrae sp. nov., Spondylurus caico-sae sp. nov., Spondylurus haitiae sp. nov., Spondylurus magnacruzae sp. nov., Spondylurus martinae sp. nov., Spondy-lurus monae sp. nov., Spondylurus monitae sp. nov., Spondylurus powelli sp. nov., and Spondylurus turksae sp. nov. Wealso resurrect 10 species from synonymies: Alinea lanceolata comb. nov., Alinea luciae comb. nov., Capitellum metalli-cum comb. nov., Mabuya dominicana, Marisora alliacea comb. nov., Marisora brachypoda comb. nov., Spondylurusfulgidus comb. nov., Spondylurus nitidus comb. nov., Spondylurus semitaeniatus comb. nov., and Spondylurus spilonotuscomb. nov. Of the 61 total species of mabuyine skinks, 39 occur on Caribbean islands, 38 are endemic to those islands,and 33 of those occur in the West Indies. Most species on Caribbean islands are allopatric, single-island endemics, al-though three species are known from Hispaniola, three from St. Thomas, and two from Culebra, St. Croix, Salt Island,Martinique, the southern Lesser Antilles, Trinidad, and Tobago. Co-occurring species typically differ in body size and be-long to different genera. Three ecomorphs are described to account for associations of ecology and morphology: terrestri-al, scansorial, and cryptozoic. Parturition occurs at the transition between the dry and wet seasons, and the number ofyoung (1–7) is correlated with body size and taxonomic group. Molecular phylogenies indicate the presence of many un-named species in Middle and South America. A molecular timetree shows that mabuyines dispersed from Africa to SouthAmerica 18 (25–9) million years ago, and that diversification occurred initially in South America but soon led to coloni-zation of Caribbean islands and Middle America. The six genera present on Caribbean islands each represent separate dis-persals, over water, from the mainland during the last 10 million years. Considerable dispersal and speciation alsooccurred on and among Caribbean islands, probably enhanced by Pleistocene glacial cycles and their concomitant sea lev-el changes. Based on IUCN Redlist criteria, all of the 38 endemic Caribbean island species are threatened with extinction.Twenty-seven species (71%) are Critically Endangered, six species (16%) are Endangered, and five species (13%) are Vul-nerable. Sixteen of the Critically Endangered species are extinct, or possibly extinct, because of human activities duringthe last two centuries. Several of the surviving species are near extinction and in need of immediate protection. Analysisof collection records indicates that the decline or loss of 14 skink species can be attributed to predation by the Small IndianMongoose. That invasive predator was introduced as a biological control of rats in sugar cane fields in the late nineteenthcentury (1872–1900), immediately resulting in a mass extinction of skinks and other reptiles. The ground-dwelling and diurnal habits of skinks have made them particularly susceptible to mongoose predation.

Factors driving sexual dimorphism and colour variability in the Achala Copper Lizard (Pristidactylus achalensis), an endemic species to the highland mountains in central Argentina

2020 ◽  
Vol 98 (6) ◽  
pp. 377-389
Author(s):  
S. Naretto ◽  
M. Chiaraviglio
Keyword(s):  
Sex Differences ◽  
Spatial Distribution ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Endemic Species ◽  
Morphological Changes ◽  
Head Size ◽  
Head Width ◽  
Temporal And Spatial Distribution ◽  
Central Argentina

The intensity of mating competition varies according to the temporal and spatial distribution of individuals. Measuring sexual dimorphism over time and interpreting the association between individuals is therefore important if we aim to understand how sexual traits are influenced. We examined sex differences in the Achala Copper Lizard (Pristidactylus achalensis (Gallardo, 1964)), an endemic species from the highest part of mountains of central Argentina. Over 4 years, we explored sex-specific variation in body size, head size, interlimb length, and body colouration. Furthermore, we evaluated how these traits varied temporally, and we also explored whether the spatial distribution of individuals is explained by variation in these traits. We found that P. achalensis is a species with sexual dimorphism in multiple characters, including body size, head size, and colouration. Interestingly, some traits related to mating, such as head width, show a temporal variability in both sexes, whereas other traits, such as colouration, varies seasonally only in males. Our results underline the intriguing possibility of seasonal morphological changes related to mating, and more broadly that sex differences are influenced by sexual selection pressures mediated by temporal variation in mate competition.

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