Head size and the foraging behaviour of animal-eating bats

1989 ◽  
Vol 67 (8) ◽  
pp. 2029-2035 ◽  
Author(s):  
M. Brock Fenton
Keyword(s):  
Regression Analysis ◽  
Body Size ◽  
Foraging Behaviour ◽  
Head Length ◽  
Analysis Of Covariance ◽  
Head Size ◽  
Linear Measurements ◽  
Maxillary Tooth ◽  
Forearm Length

Regression analysis and analysis of covariance on linear measurements of body size (forearm length), head length (condylo-canine length), and length of maxillary toothrow showed significant differences among 245 species of bats in 12 families. The linear measurements of the 194 animal-eating species, namely those in the Emballonuridae, Vespertilionidae, Phyllostominae, Rhinolophidae, Nycteridae, and Megadermatidae, showed that species of bats with longer heads had longer maxillary tooth-rows. The data also showed that some animal-eating bats which are presumed to forage from continuous flight have proportionally shorter heads than species that use sally foraging. Molossids, species specialized for rapid, efficient flight, had longer heads than expected, whereas sally-foraging hipposiderids had shorter heads. I use the data to predict that head length in animal-eating bats affects the size of prey selected.

Heads or tails? Sexual dimorphism in helodermatid lizards

2007 ◽  
Vol 85 (1) ◽  
pp. 92-98 ◽  
Author(s):  
C.M. Gienger ◽  
Daniel D. Beck
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Morphological Traits ◽  
Tail Length ◽  
Repeated Sequences ◽  
Analysis Of Covariance ◽  
Head Size ◽  
Heloderma Suspectum

We tested the hypothesis that helodermatid lizards (Gila monsters, Heloderma suspectum Cope, 1869, and beaded lizards, H. horridum (Wiegmann, 1829)) show sexual dimorphism in morphological traits related to male–male agonistic behaviors. Male–male combat in helodermatid lizards involves repeated sequences of ritualized grappling. Male Gila monsters use their heads in attempts to gain or maintain a superior position during repeated combat bouts that may last for hours. Pairs of fighting male beaded lizards form spectacular body arches, with abdomens adpressed and snouts, forelimbs, and tail tips contacting the ground. We measured body size, head size, and tail length in 208 preserved H. suspectum, and body size and tail length (but not head size) in 79 live H. horridum, then tested for sexual dimorphism using analysis of covariance. Male Gila monsters had proportionately larger heads than females but did not differ in tail length or body size. Male beaded lizards had proportionately longer tails than females and were larger in body size only when the largest individuals were included in the analysis. Differences in head dimensions (in H. suspectum) and tail length (in H. horridum) are likely the result of sexual selection acting through male–male agonistic behaviors in this unique lizard taxon.

Heads up: sexual dimorphism in house crickets (Acheta domesticus)

2008 ◽  
Vol 86 (4) ◽  
pp. 253-259 ◽  
Author(s):  
Sean E. Walker ◽  
J. Andrew Roberts ◽  
Israel Adame ◽  
Corey J. Collins ◽  
Daniel Lim
Keyword(s):  
Sex Differences ◽  
Body Size ◽  
Visual Display ◽  
Acheta Domesticus ◽  
Head Size ◽  
Visual Signal ◽  
Linear Measurements ◽  
Geometric Morphometric ◽  
Differential Selection ◽  
Males And Females

Many species are sexually dimorphic because of differential selection on each sex. In many species, males tend to have exaggerated traits or larger body size compared with females. In house crickets ( Acheta domesticus L., 1758), the males defend resources and compete for mates by engaging in a striking visual display sequence that includes mandible flaring, where males spread their mandibles wide open. This behavior presumably acts only in males as a visual signal of body size and as an indicator of the willingness to fight, as females do not exhibit this behavior. We tested the hypothesis that sex differences in the signals used for aggressive interactions will lead to sex differences in the morphology of the head in house crickets. To test this hypothesis we made linear measurements of body and head sizes on males and females and utilized geometric morphometric methods to reconstruct sex differences in shape. We also compared the total pigmented area of the faces of males and females. Males had larger heads with proportionally more pigmented area than females and there were significant shape differences. In addition, allometric relationships between head size and body size indicated that head size increases faster than body size in males. Geometric morphometric analysis indicated that the shape differences result in an exaggeration of the mandibular area in males compared with females. These data suggest that the differential selection acting on males and females can lead to differences in size, shape, and pigmentation related to signal structure and function.

scholarly journals Pattern and pace of morphological change due to variable human impact: the case of Japanese macaques

Primates ◽  
2021 ◽  
Author(s):  
Madeleine Geiger
Keyword(s):  
Body Size ◽  
Human Impact ◽  
Morphological Variation ◽  
Japanese Macaques ◽  
Linear Measurements ◽  
Skull Shape ◽  
Rates Of Change ◽  
Animal Populations ◽  
Captive Populations ◽  
In Captivity

AbstractHuman impact influences morphological variation in animals, as documented in many captive and domestic animal populations. However, there are different levels of human impact, and their influence on the pattern and rate of morphological variation remains unclear. This study contributes to the ongoing debate via the examination of cranial and mandibular shape and size variation and pace of change in Japanese macaques (Macaca fuscata). This species is ideal for tackling such questions because different wild, wild-provisioned, and captive populations have been monitored and collected over seven decades. Linear measurements were taken on 70 skulls from five populations, grouped into three ‘human impact groups’ (wild, wild-provisioned, and captive). This made it possible to investigate the pattern and pace of skull form changes among the human impact groups as well as over time within the populations. It was found that the overall skull shape tends to differ among the human impact groups, with captive macaques having relatively longer rostra than wild ones. Whether these differences are a result of geographic variation or variable human impact, related to nutritional supply and mechanical properties of the diet, is unclear. However, this pattern of directed changes did not seem to hold when the single captive populations were examined in detail. Although environmental conditions have probably been similar for the two examined captive populations (same captive locality), skull shape changes over the first generations in captivity were mostly different. This varying pattern, together with a consistent decrease in body size in the captive populations over generations, points to genetic drift playing a role in shaping skull shape and body size in captivity. In the captive groups investigated here, the rates of change were found to be high compared to literature records from settings featuring different degrees of human impact in different species, although they still lie in the range of field studies in a natural context. This adds to the view that human impact might not necessarily lead to particularly fast rates of change.

Ituglanis compactus, a new species of catfish (Siluriformes: Trichomycteridae) from the rio Jari drainage, lower Amazon, Brazil 

Zootaxa ◽  
2017 ◽  
Vol 4244 (2) ◽  
pp. 207 ◽  
Author(s):  
ÍTHALO DA SILVA CASTRO ◽  
WOLMAR BENJAMIN WOSIACKI
Keyword(s):  
New Species ◽  
Body Size ◽  
Head Length ◽  
New Taxon ◽  
Pectoral Fin ◽  
Reduced Body ◽  
Weberian Apparatus ◽  
Fin Rays ◽  
A New Species ◽  
Pectoral Fin Rays

A new species of Ituglanis is described from rio Iratapuru, near the rio Jari, Amapá, Brazil. The new species is distinguished from all congeners by the reduced number of post-Weberian apparatus vertebrae (36 or 37); the low number of paired ribs (2); the low number of interopercular odontodes (12–15); the number of branchiostegal rays (7 or 8); the presence of elongated fontanel in parieto-supraoccipital; the pectoral-fin rays (i,5); head length (18.9–25.0); and the presence of pores supraorbital s1, infraorbitals i1 and i3 of the laterosensory system. The new taxon has a reduced body size and fully ossified skeleton, but does not display a large number of paedomorphic traits compared to congeners. Comments about taxonomy and intrageneric comparisons are made, and paedomorphic in Ituglanis is discussed. Thoughts about conservation of the new species are presented. 

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 Morphometric measurements for sexual dimorphism in the Campolina horse breed

2021 ◽  
Vol 56 ◽  
Author(s):  
Lisia Castro Krebs ◽  
Marina Monteiro de Moraes Santos ◽  
Maria Claudia Siqueira ◽  
Brennda Paula Gonçalves de Araujo ◽  
Leonardo Gomes Oliveira ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Discriminant Analysis ◽  
Sexual Differentiation ◽  
Analysis Of Covariance ◽  
Classification Error ◽  
Horse Breed ◽  
Linear Measurements ◽  
Morphometric Measurements ◽  
Classification Errors ◽  
Angular Measurements

Abstract: The objective of this work was to distinguish the sexual dimorphism of horses of the Campolina breed, by morphometric measurements, and to classify them according to sex, using discriminating functions. Two-hundred and fifteen horses were measured, and 39 morphometric measurements were evaluated. The analysis of covariance and the discriminant analysis were performed. Males were taller and showed a wider chest, a greater scapular-humeral angle, and a larger neck, both in length and circumference. Females had a larger heart girth, wider hips, and a greater opening of the coxal-ground and femorotibial angles. Regarding classification, circumference measurements (85.58%) were more accurate in sexual differentiation than the linear (83.26%) and angular (73.02%) ones. As to classification error, of the total animals measured, 10 to 20% of the females were categorized as males. In addition, 11 to 38% of the males were categorized as females. It can be concluded that of the 39 morphometric measurements evaluated, 22 are responsible for sexual dimorphism in the Campolina horse breed. Circumference and linear measurements provide a more assertive classification to determine sexual dimorphism. Angular measurements show greater classification errors regarding the gender of the horses.

scholarly journals Body size information in large-scale acoustic bat databases

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5370 ◽  
Author(s):  
Caterina Penone ◽  
Christian Kerbiriou ◽  
Jean-François Julien ◽  
Julie Marmet ◽  
Isabelle Le Viol
Keyword(s):  
Body Size ◽  
Large Scale ◽  
Principal Component ◽  
Acoustic Signals ◽  
Species Traits ◽  
Climatic Variables ◽  
Characteristic Frequencies ◽  
Acoustic Data ◽  
Forearm Length ◽  
Broad Scale

Background Citizen monitoring programs using acoustic data have been useful for detecting population and community patterns. However, they have rarely been used to study broad scale patterns of species traits. We assessed the potential of acoustic data to detect broad scale patterns in body size. We compared geographical patterns in body size with acoustic signals in the bat species Pipistrellus pipistrellus. Given the correlation between body size and acoustic characteristics, we expected to see similar results when analyzing the relationships of body size and acoustic signals with climatic variables. Methods We assessed body size using forearm length measurements of 1,359 bats, captured by mist nets in France. For acoustic analyses, we used an extensive dataset collected through the French citizen bat survey. We isolated each bat echolocation call (n = 4,783) and performed automatic measures of signals, including the frequency of the flattest part of the calls (characteristic frequency). We then examined the relationship between forearm length, characteristic frequencies, and two components resulting from principal component analysis for geographic (latitude, longitude) and climatic variables. Results Forearm length was positively correlated with higher precipitation, lower seasonality, and lower temperatures. Lower characteristic frequencies (i.e., larger body size) were mostly related to lower temperatures and northern latitudes. While conducted on different datasets, the two analyses provided congruent results. Discussion Acoustic data from citizen science programs can thus be useful for the detection of large-scale patterns in body size. This first analysis offers a new perspective for the use of large acoustic databases to explore biological patterns and to address both theoretical and applied questions.

scholarly journals Convergence in reduced body size, head size, and blood glucose in three island reptiles

2018 ◽  
Vol 8 (12) ◽  
pp. 6169-6182 ◽  
Author(s):  
Amanda M. Sparkman ◽  
Amanda D. Clark ◽  
Lilly J. Brummett ◽  
Kenneth R. Chism ◽  
Lucia L. Combrink ◽  
...  
Keyword(s):  
Body Size ◽  
Blood Glucose ◽  
Head Size ◽  
Reduced Body

Calibration of Test Diameter and Area As Proxies For Body Size in the Planktonic Foraminifer Globoconella Puncticulata

2018 ◽  
Vol 48 (3) ◽  
pp. 241-245 ◽  
Author(s):  
Anieke Brombacher ◽  
Leanne E. Elder ◽  
Pincelli M. Hull ◽  
Paul A. Wilson ◽  
Thomas H. G. Ezard
Keyword(s):  
Body Size ◽  
Morphological Change ◽  
Statistical Power ◽  
Three Dimensional ◽  
Body Volume ◽  
Test Diameter ◽  
Linear Measurements ◽  
Cross Sectional ◽  
Test Volume ◽  
Computed Tomography Scanning

Abstract Body size is one of the most commonly measured traits in ecology and evolution because it covaries with environmental (e.g., temperature, latitude, degree of population isolation) and life-history (e.g., metabolic rate, generation time) traits. However, the driving mechanisms of body size variation in the distant geological past are poorly known and complicated by partial specimen recovery, limited population-level sampling, and the use of linear measurements as proxies for three-dimensional volumetric-size data. How much information are we missing by using approximate metrics of body size? Here we examine this question in an evolving lineage of planktonic foraminifera. We measure test diameter and surface area of over 500 individuals of the species Globoconella puncticulata using two-dimensional images. These results are compared with measurements of test volume of the same individuals as measured by a recently developed high-throughput method for analysing three-dimensional morphometrics as well as high-resolution three-dimensional computed tomography scanning. Our results show that even in a lineage showing substantial morphological change, a cross-sectional test area can provide a consistent proxy for body volume. Approximating body volume with one-dimensional (linear) size measurements is more problematic as it systematically over- and underestimates the smallest and largest tests, respectively. In our study, shape (here measured as shell-aspect ratio) only explained marginally more variation when included in the regressions. The use of 3D light microscopy introduces a small degree of scatter in the data, but the number of individuals necessary to detect trends in body size with sufficient statistical power is comparable to the sample size required for other traits. These results imply that even in an evolving lineage undergoing substantial morphological change, cross-sectional area can provide a consistent proxy for body size.

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