Hind Leg Length Research Articles

The role of habitat shift in the evolution of lizard morphology: evidence from tropical Tropidurus.

We compared morphology of two geographically close populations of the tropical lizard Tropidurus hispidus to test the hypothesis that habitat structure influences the evolution of morphology and ecology at the population level. T. hispidus isolated on a rock outcrop surrounded by tropical forest use rock crevices for refuge and appear dorsoventrally compressed compared with those in open savanna. A principal components analysis revealed that the populations were differentially distributed along an axis representing primarily three components of shape: body width, body height, and hind-leg length. Morphological divergence was supported by a principal components analysis of size-free morphological variables. Mitochondrial DNA sequences of ATPase 6 indicate that these populations are closely related relative to other T. hispidus, the rock outcrop morphology and ecology are derived within T. hispidus, and morphological and ecological divergence has occurred more rapidly than genetic divergence. This suggests that natural selection can rapidly adjust morphology and ecology in response to a recent history of exposure to habitats differing in structure, a result heretofore implied from comparative studies among lizard species.

Gait, estimated net cost of transport and heat production at different speeds in Three‐day‐event horses

Heart rate and gait characteristics (stride length and frequency) were studied in 6 horses subjected to a standardised incremental exercise test, involving moving at the trot and increasing speeds up to a fast gallop and subsequently during the steeplechase phase of a 3-day-event. The studies were performed in hot conditions. Appropriate scaling, based on hindleg length (hh), stride length (L), stride frequency (f) and speed (Sp) for nondimensional stride length (lambda = (L/hh), nondimensional stride frequency (phi = f(hh/g)1/2) and nondimensional velocity (û = Sp/(ghh)1/2), where g is the gravitational acceleration, demonstrated that there were no major differences in characteristics over the full range studied lambda = 2.3 û0.68. However, there were subtle differences in some horses that could endow a benefit in locomotory efficiency when compared to others exercising at the same absolute speed. There were clear changes in the relationship between nondimensional stride length and frequency with increasing speed, from trot to canter (at û approximately 1.4) and to full gallop (at û approximately 2.3); when trotting, lambda was less than 2.2 and the transition from canter to gallop took place at lambda approximately 3.2. The cost of transport/kg/m, estimated from the heart rates measured continuously during each study, decreased with increasing speed and bodyweight. In some animals, there appeared to be a weak minimum around the canter-gallop transition speed. When interpreted as oxygen cost, using published values for the oxygen consumption-heart rate relationship, the cost fell from an average of 0.201 ml/kg/m at the trot to 0.161 mlO2/kg/m when galloping during the incremental exercise tests. During the steeplechase, the cost was approximately 7.5% higher than at the same speed in the exercise tests; this was probably due to jumping effort. Estimated power consumption increased linearly with speed. In the steeplechase, power consumption was also 7.5% higher than during the exercise tests at the same absolute speed; this was equivalent to an average rate of heat production of 346 kcal/min (24 kW) or 59.5 kcal/min/m2 of the measured body surface area.

Caste allometries in the soldier-producing aphidPseudoregma alexanderi (Hormaphididae: Aphidoidea)

Colonies of the aphidPseudoregma alexanderi produce morphologically-specialized first-instar larvae, termed soldiers, that defend the colony from predators. The environmental cues and physiological mechanisms governing soldier production are currently unknown. Here we present a morphometric study of soldiers and normal first-instar larvae ofP. alexanderi. Several morphological features (fore-leg length and width, hind-leg length, and horn length) plotted against body length display relationship that are similar to a sigmoidal curve. We found further support for an earlier finding that soldiers fall into two size categories, majors and minors, although both types of soldiers appear to follow the same allometry. The patterns of allometry in the soldier-producing aphids are very different from those found in other social insects and do not easily fit into the traditional categorization of allometries. We present two simple alternative models of soldier development as a framework for guiding future studies of the mechanisms of soldier production.

Neivamyrmex curvinotus n. sp. (HymenopteraL Formicidae: Ecitoninae) from South America.

Neivamyrmex curvinotus n. sp. (HymenopteraL Formicidae: Ecitoninae) from South America.

Allometry and the geometry of leaf-cutting in Atta cephalotes

This study considers the relationship of both leg length and the geometry of leaf-cutting to load-size determination by the highly polymorphic leaf-cutting ant Atta cephalotes. A. cephalotes workers anchor on the leaf edge by their hind legs and pivot around them while cutting arcs from leaves. I tested the hypothesis that, for an ant cutting a semicircular leaf fragment, fragment area is determined by a fixed “reach” while cutting. This “reach hypothesis” predicts that ants should cut the same fragment-area for at all leaf types. Also, if the radius of the semicircular fragment is proportional to hind leg length, this hypothesis predicts that leaf area should be proportional to hind-leg length squared. The field work was carried out in March–April 1990 and June 1991 in Heredia Province, Costa Rica. I measured hind-leg length for workers of different masses. I then measured leaf-fragment area and mass for workers cutting semicircular fragments from leaves of different densities (mass/area). The logarithmic relationship between ant mass (Ma) and hind-leg length L accelerated negatively (Fig. 1). As a result of this “complex” allometry, relative leg length (L/Ma0.33) increased with ant mass up to a mass of 7.4 mg. Above 7.4 mg, relative leg length decreased. For foragers cutting semicircular fragments, the area cut by an ant of a given size showed no significant difference among leaves of different densities (Fig. 2). Leaf area (A) increased as a function of leg length to the 1.9 power (Fig. 4), an exponent not significantly different from the square function expected if the radius of a fragment is determined by the ant's “reach”. As a result of this consistent mode of fragment-area determination, the mass of fragments cut by an ant of a given size was significantly greater when cutting denser leaves (Fig. 3) and relative area (A/Ma) cut decreased with increasing ant mass. However, because larger ants generally cut denser leaves (Table 1), the increased density of thick leaves was offset by the reduced relative area cut by the larger ants. Overall, 93% of the foragers cut fragments weighing between 1.5 and 6 times their own body mass (Table 1). Earlier studies found that this broad load-mass range maximized the biomass-transport rate (mass/distance/time) and transport efficiency (mass/distance/energy cost). Thus, A. cephalotes does not solve the problem of matching ant mass and load mass at leaves of different densities with flexibility in the leaf-cutting behavior of individual ants. Instead, individual ants employ a single simple behavioral rule, but workers of different sizes and body proportions tend to cut leaves of different densities.

Muscle: Bone ratios in beef rib sections

Thirty-eight steers and thirty heifers (14 to 17 months of age, from F 1 Hereford × Brahman cows bred to Angus or Hereford bulls), were either forage-fed for 123 days on millet-bermudagrass pasture or grain-fed for 90 days on a high-concentrate diet and were then commercially slaughtered. Warm carcass weights ranged from 167·8 kg to 324·3 kg. At 24 h post mortem, Texas Agricultural Experiment Station personnel (1) assigned scores or took measurements on each carcass for all factors used in yield grading and quality grading, (2) measured the length of hind leg (HL) and carcass length (CL) and (3) assigned a score for carcass muscling (MS) and, as appropriate, made an adjusted longissimus muscle area (ALA) evaluation. The 9th-10th-11th rib section from one side of each carcass was physically separated into longissimus muscle, fat, ‘other soft tissue’ and bone and ether extract determinations of the longissimus muscle and ‘other soft tissue’ components were made and used to adjust the yields of each of these components to a fat-free basis. Muscle to bone ratios ranged from 2·38 to 4·37. With both age and carcass weight held constant, diet, breed and sex explained only 35·8% of the variation in muscle to bone ratio. The best simple correlation with muscle to bone ratio was ALA/CL ( r = ·59). Other measures significantly correlated with muscle to bone ratio included ALA ( r = 0·55), MS ( r = 0·50) and carcass weight ( r = 0·49). Multiple regression analyses identified a three-variable subset comprised of ALA, carcass weight and CL which was related ( P < 0·01) to muscle to bone ratio R 2 = 0·41). Data suggest that muscle to bone ratios differ widely among beef carcasses of similar genetic-management history and that there are carcass measures useful for predicting muscle to bone ratio.

The effect on reproduction and morphometrics of females ofCulex pipiensL. of treatment of larvae with six insect growth regulators

SUMMARYSix compounds which show juvenile-hormone-like (JH) activity (TH6040, JH-25, Altosid, Altozar, ZR-777 and ZR-619) were tested on larvae ofCulex pipiens. The reproduction potential of the females obtained during two successive generations was not affected greatly, but there was a decline in pupation rate with some compounds. There seemed to be a direct relationship between the size of females of this species and treatment with JH compounds tested in the present investigation, since treatment with concentrations to inhibit the emergence of 10% or 50% of adults caused significant changes in the width of head, wing dimensions or length of hind legs.

A note on the response of wether lambs to treatment with trenbolone acetate combined with oestradiol-17β or zeranol

ABSTRACTTwenty-five Greyface wether lambs were allocated at approximately 40 kg live weight to be slaughtered, to be untreated controls, or to be implanted with 57·5 mg trenbolone acetate plus 8·1 mg oestradiol-17β (treatment To8), 60mg trenbolone acetate plus lOmg oestradiol-17β (treatment To10) or 70mg trenbolone acetate plus 12 mg zeranol (treatment TZ). The control and treated lambs were slaughtered after 63 days. Effects on live-weight gain were small and not significant. On average, hormonal treatments resulted in: (a) significant increases in dressing percentage, gain in carcass weight and carcass protein, kidney weight (g/kg live weight), depth of thorax and in the activity of liver tyrosine amino transferase; and (b) variable reductions in hind leg length, concentration of plasma urea and (g/kg live weight) kidney fat, mesenteric fat and fleece. Significant differences recorded between treatments included the conversion of food into carcass protein (treatments To8 and TO10 v. TZ) and mesenteric fat (g/kg live weight) and fat cover at the 12th rib (treatment To8v To10).

Differences between groups of lamb carcasses chosen for good and poor conformation

SUMMARYNinety-six lamb carcasses drawn from six batches of lambs commercially consigned to an abattoir were analysed for characteristics which may affect their economic value. From each batch carcasses were selected in equal numbers into two classes of ‘good’ or ‘poor’ conformation according to traditional standards. Carcasses selected for ‘good’ conformation were heavier (P&lt;0·05) and fatter (P&lt;0·05), slightly shorter in carcass length and hind leg length (P&lt;0·05), greater in circumference (P&lt;0·001) and width (P&lt;0·001) of the hind leg, slightly greater in muscle weight (P&lt;0·05) but no greater in bone weight than those of poor conformation. The yield of prime retail joints was similar in the two conformation classes but the ‘good’ conformation class had a higher proportion of loin and rib joints and lower proportion of hind leg joint (P &lt; 0·01) although these differences were not considered to be of commercial importance. There was a lower proportion of the carcass fatty tissue in the hind leg joint of the ‘good’ conformation class (P &lt; 0·05). Muscle-to-bone ratio and area of ‘eye muscle’ (M. longissimus thoracis) appeared to be little affected by selecting for conformation differences. Depth of fleshing as indicated by the weight of muscle in the hind leg per 10 cm length, was 40 g (6%) heavier in the carcasses of the ‘good’ conformation class. This contrasted with the much greater differences, between batches, of 290 g (40 to 50%). Between batches there were significant differences for all the measures taken except the yield of preferred retail cuts. In the main the batch differences were greater and commercially more important than the conformation class differences.

Ecology of the Iguanid Lizard Callisaurus draconoides

Various aspects of the life history of Callisaurus are described and discussed, including: movements, microhabitat, foraging behavior, diet, size, growth, age, population structure, reproduction, sexual dimorphism, sex ratio, abundance, thermoregulation, time of activity, tail loss and predation, and leg length. Callisaurus hatchlings emerge from mid-July through November and grow rapidly, with most individuals attaining minimum adult size at ages of less than a year. Mean distance between captures was 20.3 m in seven immatures and 31.9 m in six adults. Mean growth rate of nine first-year lizards was 6.5 mm per month. One or more clutches of two to eight eggs are laid annually (mean of 73 clutches: 4.42). Oviducal eggs, and presumably egg deposition as well, occur from early June through at least late August. Males have enlarged testes from April through mid-August on southern areas, whereas on northern areas testes are reduced in size during late July and August, suggesting a shorter breeding season in the north. Clutch size is not correlated with female snout-vent length or with any of several measures of precipitation. Estimates of abundance vary from about .02 to 1.75 lizards per hectare, but are not correlated with the percentage of open ground, or with any of several precipitation statistics. There are latitudinal shifts in diet and percentage of females with broken and regenerated tails, and it is likely that the available prey and the level of predation differ within the geographic range. The frequency of broken tails increases with size, perhaps reflecting increased numbers of contacts with predators as the lizards age. Both the forelegs and the hindlegs of Callisaurus, expressed as percentages of snout-vent length, are significantly longer than the same measurements on eight other species of North American desert iguanids. Hindleg length is correlated with the frequency of use of open spaces in North American flatland desert lizards. Various aspects of the ecology of Callisaurus are briefly compared with those of some related and/or ecologically similar species of lizards.

Morphometric Characterization And Relationship Of Body Weight With Linear Body Measurements In Black Bengal Buck

The present study was conducted at the Artificial Insemination Center, Bangladesh Agricultural University, Mymensingh to record the Black Bengal bucks morphology and to relate body weight with different body measurements. A total of 22 Black Bengal bucks of different ages were taken and were divided into six age groups (0, 3, 6, 9, 12 and 15 months). The body weight of Black Bengal bucks at 0, 3, 6, 9, 12 and 15 months of age were 1.21 ± 0.12, 4.26 ± 0.25, 7.68 ± 0.31, 12.76 ± 0.42, 16.56 ± 0.57 and 21.82 ± 0.70 kg respectively. Age had a significant effect (P&lt;0.05) on heart girth, body length and height at wither (P&lt;0.05) except the measurement of height at wither at 0 and 3 months. The measurement of fore and hind leg length, head length and width, ear length and breadth and also tail length differed significantly (P&lt;0.05) between the age groups. The average scrotal circumferences (SC) were recorded as 4.85 ± 0.22, 10.35 ± 0.39, 15.42 ± 0.34, 18.05 ± 0.24, 19.72 ± 0.33 and 20.83 ± 0.41 cm at 0, 3, 6, 9, 12 and 15 months of age, respectively and differed significantly (P&lt;0.05) with the advancement of age. Animals of the same age group supposed to be similar in conformation. Body weight was highly correlated (P&lt;0.01) with heart girth (0.94), body length (0.95) and height at wither (0.96). DOI: http://dx.doi.org/10.3329/bjas.v37i2.9876 BJAS 2008; 37(2): 8-16

Characterization of Black Bengal goat

Characterization of Black Bengal bucks and does was performed in this study. A total of 50 goats of different aged were studied. The experiment was performed in Black Bengal bucks and does at 1&lt;sup&gt;st&lt;/sup&gt; day and at 3, 6, 9 and 12 months of age for measuring different parameters such as body length, heart girth, wither height, hip height, fore and hind leg length, head length and width, head length and width, ear length and ear breath, scrotal length and scrotal circumference. In a single parameter as body weight of Black Bengal bucks and does at 1&lt;sup&gt;st&lt;/sup&gt; day and at 3, 6, 9 and 12 months of age were found to be 1.08±0.06, 5.22±0.33, 8.95±0.34, 12.05±0.47 and 14.20±0.20; and 1.01±0.23, 3.93±0.19, 7.41±0.27, 9.53±0.38 and 12.40±0.41 kg respectively. Whereas all the finding where gradually increased for all parameters according to their specific age periods. Body weight has a strong positive relationship with heart girth, body length, height at wither, scrotal length and scrotal circumference in Black Bengal goat. All the parameters studied found comparatively higher in bucks than does. Keywords: Black Bengal goat; Characterization; Body parts; Analysis DOI: http://dx.doi.org/10.3329/jbau.v9i1.8745 JBAU 2011; 9(1): 61-66

Phenotypic Characteristics Of Indigenous Sheep Of Bangladesh

This experiment was undertaken to know the phenotypic characteristics of native sheep. The study was conducted to investigate morphometric characters of sheep in three different field sites (Naogaon, Noakhali and Tangail) and Bangladesh Livestock Research Institute (BLRI) nucleus flock through close observation, measuring and record keeping. Characteristics of body weight, body length, heart girth, wither height, fore leg length, hind leg length, head length, ear length, ear width, horn length etc were collected from mature sheep. The results indicate that the average litter size, birth weight, weaning weight and body weight gain were comparatively higher in sheep of BLRI nucleus flock than those of other three regions. The average numbers of service/conception, post partum heat period (days), age at first heat (days), age at first lambing (days), lambing interval (days) were 1.30, 34.13, 266.50, 432.72, 192.17 respectively in BLRI nucleus flock which were comparatively better than the other three regions. The average litter size, birth weight (kg), weaning weight (kg) and body weight gain (g) in nucleus flock were 1.80, 1.19, 6.74 and 60.70 consequently. The overall performance of the sheep of BLRI nucleus flock were comparatively better than the others which may be due to the result of selective breeding, improve feeding, housing, health management etc. DOI: http://dx.doi.org/10.3329/bjas.v38i1-2.9906 BJAS 2009; 38(1-2): 1-6

The effect of rate of gain during the growing and finishing periods on the feed efficiency and carcass composition of the pig: II. Contrasting patterns of growth produced by different rates of gain from 20 to 55 kg and 55 to 87 kg live weight

SUMMARYPigs were grown at controlled rates of live-weight gain from 20 to 55 kg and from 55 to 87 kg live weight, at which weight they were slaughtered. Six growth-rate treatments were compared and were referred to as High-High (HH), High-Moderate (HM), High-Low (HL), Moderate-High (MH), Moderate-Moderate (MM) and Low-High (LH). The right-hand side of each carcass was divided into the four primary jointsand each joint was physically dissected into bone, skin, subcutaneous fat and lean meat. The boneless tissue of each joint was analyzed for moisture, ether extractable fat and nitrogen.It was found that an increase in the rate of live-weight gain in the first growth period, tended toimprove the efficiency with which feed was converted into live weight. In the second growth period the efficiency of feed conversion was dependent on the rate of gain both in that period and in the preceding period. Restricted growth in the first period improved the efficiency of feed conversion both in the second period and over the entire experimental period compared with rapid early growth. The implications of compensatory growth are discussed.There was no treatment effect on carcass length, but hindleg length and ham circumference measurements showed that the proportion of gammon in the side was lower in the HH pigs compared with the other five treatments. This was confirmed by the weight of the gammon joint expressed as a percentage of the trimmed side. There was also a decrease in the proportion of shoulder and an increase in the proportion of middle in the HH pigs. Differences between the other five treatments were small. The changes in conformation were due largely to the effect on fat distribution throughout the side particularly in the gammon and back regions.The HH treatment resulted in a significant increase in the percentage fat in the side compared witheach of the other five treatments. Within these five treatments there was no significant difference in the percentage fat in the side. This suggests that equal importance may be attached to the rate of live-weight gain in both the growing (20–55 kg) and finishing (55–87 kg) periods in determining the fatnessof the bacon weight carcass.The treatments had little effect on the chemical composition of the fat-free boneless meat.The results are discussed in relation to current growth theory.

Assay of thyroid-stimulating hormone, thyroid and thyroid-like substances on Xenopus tadpoles.

IN 1941, Landgrebe and Purser1 showed that larvae of Xenopus laevis can be obtained in the laboratory all the year round, and suggested that they could be used for assay of thyroid and thyroid stimulating hormone. In 19452, Deanesly and Parkes published a method for assay of thyroid-like activities by oral administration, using these tadpoles at an early stage. Such animals, however, vary a great deal in sensitivity and are too small for satisfactory injection and operative surgery. In the past few years, the anatomy, feeding mechanism, growth, food requirements, development and metamorphosis of the larvae have been thoroughly investigated. Methods for routine thyroidectomy and injection of extracts have been worked out using larger tadpoles. Methods of husbandry have been devised which reduce individual variation to a minimum, and produce large metamorphically retarded larvae suitable for assay work (c. 400 mgm. with length of hind leg c. 0.3 cm.).

A Case of Hermaphroditism in Rana catesbeiana Shaw

A CASE OF HERMAPHRODITISM IN RANA CA TESBEIANA SHAW.-The records of hermaphroditism in the Anura are not rare in the literature but very few instances of such a condition have been recorded for American species (Evans, 1931). This fact may be considered of some significance in view of the large number of specimens which are examined yearly in this country. The writer is aware of only three records of hermaphroditism in Rana catesbeiana, the form most commonly used in laboratory studies (Clemens, 1921; Chidester, 1926; Behney, 1933). The individual concerned in the present report was obtained from a biological supply house in Dallas, Texas. No record of the date or place of collection could be found, It is of medium size: the length from anus to tip of snout, 12.8 cm.; length of right hind leg from anus to tip of fourth digit, 18.2 cm.; diameter of tympanic membrane, 1.3 cm.; length across the mouth at the angle of the jaws, 4.8 cm. There are no external secondary sex characters present. Vocal sacs and thumb pads are totally absent. The external condition of the sex organs is shown in the figure. On the right side there is an almost spherical testis with a single pigmented groove on the ventral surface. The diameter of this testis is .6 cm. There are seven vasa efferentia present in the mesorchium. There is a medium sized ovary (5.4 cm. along outside margin) on the left side. This tissue is thin and apparently underdeveloped. There is no evidence of the presence of an oviduct in the body cavity. Histological sections were made of the testis and ovary. The sections of the testis appeared normal and were filled with mature spermatozoa. No ova were found in the organ as has been reported in other cases. The ovary contained a large number of follicles, each of which possessed several small follicular cells. No developing or mature ova were found in the female organ.

Pigmentary Reaction in Rana Clamitans Larvae Following Treatments With X-Rays.

Incidental to experiments on the effects of x-rays on the sex-glands of Rana clamitans tadpoles, our attention was drawn to certain conspicuous changes in the dorsal skin, especially the formation of whirls by the epidermal melanophores preceding their disintegration. The animals, after being narcotized in a 1:10,000 solution of water-soluble anesthesin, were placed on water-soaked cellucotton and exposed to unfiltered x-rays. A Victor Snook unit, with a universal air-cooled broad focus Coolidge tube was used to produce x-rays of different qualities. In the normal skin we find 2 types of brown melanophores: first, the asterisk-shaped pigment cells of the stratum corium (Figs. 2 and 6c), which are distributed evenly over the back and flanks of the larvae. To them is due the general slate color of the dorsal skin (Fig. 1). Secondly, we find the filiform melanophores of the epidermis (Figs. 4 and 6e). They exhibit a remarkable tendency to form aggregations thus giving rise to the characteristic black spots on the back of the clamitans tadpole. It is well known that the so-called experimental albinism obtained upon hypophysectomy is largely due to the extreme contraction of the epidermal melanophores. We describe here only 2 stages of the pigmentary reaction following x-ray treatment. In the first case 10 tadpoles, of 43-45 mm. body length, and 8-10 mm. hind leg length, were given 8 treatments of 92 kilovolts 5 milliamperes, at 10 inches from the cathode. The animals were exposed for 10 minutes every other day and killed 6 days after the last treatment. Towards the end of the treatment the previously round pigment dots become streaky or comma-shaped. Later they begin to converge towards one or several centers which most often are located in the scapular and pelvic regions (Fig. 3, 22 days after the beginning of treatment).