scholarly journals Nutrition and ontogeny influence weapon development in a long-lived mammal

2018 ◽  
Vol 96 (9) ◽  
pp. 955-962 ◽  
Author(s):  
P.D. Jones ◽  
B.K. Strickland ◽  
S. Demarais ◽  
G. Wang ◽  
C.M. Dacus
Keyword(s):  
Body Mass ◽  
Lifetime Reproductive Success ◽  
Positive Allometry ◽  
Selective Pressures ◽  
Antler Growth ◽  
Competing Demands ◽  
Weapon Development ◽  
Antler Size ◽  
Allocation Decisions ◽  
Older Males

Selection in male cervids should optimize allocation of nutritional resources to the competing demands of body growth versus weapon development. We investigated allocation decisions of growing and mature male white-tailed deer (Odocoileus virginianus (Zimmerman, 1780)) from three regions of low, moderate, and high diet quality. We tested (i) if deer under greater nutritional limitations would allocate proportionally less to antler growth, (ii) if antler and body mass became less variable with age, and (iii) if antler size consistently exhibited positive allometry with body mass across age classes and nutritional planes. Greater nutrition increased antler allocation in 2.5 to 4.5 year olds but not in yearlings or prime-aged males. Variability of antler mass decreased with age and was generally less in more fertile regions, but body mass was equally variable across all ages and regions. Antler mass was positively allometric with body mass for all combinations of age class and region but exhibited age- and region-related differences. Our results suggest that accruing body mass is more important to lifetime reproductive success than increasing weapon size. Reduced allometric coefficients in older males likely stem from increasing use of skeletal mineral reserves, selective pressures favoring greater body mass, and possible selection for optimal weapon strength and structure.

scholarly journals Mechanics of evolutionary digit reduction in fossil horses (Equidae)

2017 ◽  
Vol 284 (1861) ◽  
pp. 20171174 ◽  
Author(s):  
Brianna K. McHorse ◽  
Andrew A. Biewener ◽  
Stephanie E. Pierce
Keyword(s):  
Body Mass ◽  
Bone Geometry ◽  
Continuous Measure ◽  
Positive Allometry ◽  
Load Bearing ◽  
Beam Analysis ◽  
Body Sizes ◽  
Major Trend ◽  
The Cost

Digit reduction is a major trend that characterizes horse evolution, but its causes and consequences have rarely been quantitatively tested. Using beam analysis on fossilized centre metapodials, we tested how locomotor bone stresses changed with digit reduction and increasing body size across the horse lineage. Internal bone geometry was captured from 13 fossil horse genera that covered the breadth of the equid phylogeny and the spectrum of digit reduction and body sizes, from Hyracotherium to Equus . To account for the load-bearing role of side digits, a novel, continuous measure of digit reduction was also established—toe reduction index (TRI). Our results show that without accounting for side digits, three-toed horses as late as Parahippus would have experienced physiologically untenable bone stresses. Conversely, when side digits are modelled as load-bearing, species at the base of the horse radiation through Equus probably maintained a similar safety factor to fracture stress. We conclude that the centre metapodial compensated for evolutionary digit reduction and body mass increases by becoming more resistant to bending through substantial positive allometry in internal geometry. These results lend support to two historical hypotheses: that increasing body mass selected for a single, robust metapodial rather than several smaller ones; and that, as horse limbs became elongated, the cost of inertia from the side toes outweighed their utility for stabilization or load-bearing.

scholarly journals Ontogenetic scaling patterns and functional anatomy of the pelvic limb musculature in emus (Dromaius novaehollandiae)

2014 ◽  
Author(s):  
Luis P Lamas ◽  
Russell P Main ◽  
John R. Hutchinson
Keyword(s):  
Body Mass ◽  
Functional Anatomy ◽  
Major Axis ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Positive Allometry ◽  
Dromaius Novaehollandiae ◽  
Pelvic Limb

Emus (Dromaius novaehollandiae) are exclusively terrestrial, bipedal and cursorial ratites with some similar biomechanical characteristics to humans. Their growth rates are impressive as their body mass increases eighty-fold from hatching to adulthood whilst maintaining the same mode of locomotion throughout life. These ontogenetic characteristics stimulate biomechanical questions about the strategies that allow emus to cope with their rapid growth and locomotion, which can be partly addressed via scaling (allometric) analysis of morphology. In this study we have collected pelvic limb anatomical data (muscle architecture, tendon length, tendon mass and bone lengths) and calculated muscle physiological cross sectional area (PCSA) and average tendon cross sectional area from emus across three ontogenetic stages (n=17, body masses from 3.6 to 42 kg). The data were analysed by reduced major axis regression to determine how these biomechanically relevant aspects of morphology scaled with body mass. Muscle mass and PCSA showed a marked trend towards positive allometry (26 and 27 out of 34 muscles respectively) and fascicle length showed a more mixed scaling pattern. The long tendons of the main digital flexors scaled with positive allometry for all characteristics whilst other tendons demonstrated a less clear scaling pattern. Finally, the two longer bones of the limb (tibiotarsus and tarsometatarsus) also exhibited positive allometry for length and the two others (femur and first phalanx of digit III) had trends towards isometry. These results indicate that emus experience a relative increase in their muscle force-generating capacities, as well as potentially increasing the force-sustaining capacities of their tendons, as they grow. Furthermore, we have clarified anatomical descriptions and provided illustrations of the pelvic limb muscle-tendon units in emus.

scholarly journals Ontogenetic scaling patterns and functional anatomy of the pelvic limb musculature in emus (Dromaius novaehollandiae)

2014 ◽  
Author(s):  
Luis P Lamas ◽  
Russell P Main ◽  
John R. Hutchinson
Keyword(s):  
Body Mass ◽  
Functional Anatomy ◽  
Major Axis ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Positive Allometry ◽  
Dromaius Novaehollandiae ◽  
Pelvic Limb

Emus (Dromaius novaehollandiae) are exclusively terrestrial, bipedal and cursorial ratites with some similar biomechanical characteristics to humans. Their growth rates are impressive as their body mass increases eighty-fold from hatching to adulthood whilst maintaining the same mode of locomotion throughout life. These ontogenetic characteristics stimulate biomechanical questions about the strategies that allow emus to cope with their rapid growth and locomotion, which can be partly addressed via scaling (allometric) analysis of morphology. In this study we have collected pelvic limb anatomical data (muscle architecture, tendon length, tendon mass and bone lengths) and calculated muscle physiological cross sectional area (PCSA) and average tendon cross sectional area from emus across three ontogenetic stages (n=17, body masses from 3.6 to 42 kg). The data were analysed by reduced major axis regression to determine how these biomechanically relevant aspects of morphology scaled with body mass. Muscle mass and PCSA showed a marked trend towards positive allometry (26 and 27 out of 34 muscles respectively) and fascicle length showed a more mixed scaling pattern. The long tendons of the main digital flexors scaled with positive allometry for all characteristics whilst other tendons demonstrated a less clear scaling pattern. Finally, the two longer bones of the limb (tibiotarsus and tarsometatarsus) also exhibited positive allometry for length and the two others (femur and first phalanx of digit III) had trends towards isometry. These results indicate that emus experience a relative increase in their muscle force-generating capacities, as well as potentially increasing the force-sustaining capacities of their tendons, as they grow. Furthermore, we have clarified anatomical descriptions and provided illustrations of the pelvic limb muscle-tendon units in emus.

Gill and Body Surface Areas of the Carp in relation to Body Mass, With Special Reference To The Metabolism-Size Relationship

1985 ◽  
Vol 117 (1) ◽  
pp. 1-14 ◽  
Author(s):  
SHIN OIKAWA ◽  
YASUO ITAZAWA
Keyword(s):  
Special Reference ◽  
Body Mass ◽  
Body Surface ◽  
Larval Stage ◽  
The Body ◽  
Positive Allometry ◽  
Surface Areas ◽  
Gill Area ◽  
Resting Metabolism ◽  
The Relationship

The relationships of resting metabolism per unit mass of body to gill and body surface areas were examined by measuring gill, body surface and fin areas of carp ranging from 0.0016 to 2250g. There was a triphasic allometry for the relationship between gill area and body mass: during the prelarval (0.0016–0.003 g) and postlarval (0.003–0.2g) stages there was a positive allometry (slopes of 7.066 and 1.222, respectively), during the juvenile and later stages (0.2–2250 g) there was a negative allometry with a slope of 0.794. There was a diphasic negative allometry for the relationship between surface area of the body or the fins and body mass, with a slope of 0.596 or 0.523 during the larval stage and 0.664 or 0.724 during the juvenile and later stages, respectively. Except for the 3rd phase (juvenile to adult) of gill area, these slopes were significantly different (P<0.01) from the slope for the relationship between resting metabolism and body mass of intact carp (0.84; value from Winberg, 1956). It is considered, therefore, that gill, body surface and fin areas do not directly regulate the resting metabolism of the fish, in the larval stage at least.

Body mass influences maternal allocation more than parity status for a long-lived cervid mother

2019 ◽  
Vol 100 (5) ◽  
pp. 1459-1465 ◽  
Author(s):  
Eric S Michel ◽  
Stephen Demarais ◽  
Bronson K Strickland ◽  
Jerrold L Belant ◽  
Larry E Castle
Keyword(s):  
Reproductive Success ◽  
Body Mass ◽  
Litter Size ◽  
Reproductive Value ◽  
Lifetime Reproductive Success ◽  
Reproductive Tactics ◽  
High Quality ◽  
Maternal Body ◽  
Individual Offspring ◽  
Maternal Allocation

Abstract Mothers should balance the risk and reward of allocating resources to offspring to optimize the reproductive value of both offspring and mother while maximizing lifetime reproductive success by producing high-quality litters. The reproductive restraint hypothesis suggests maternal allocation should peak for prime-aged mothers and be less for younger mothers such that body condition is not diminished to a level that would jeopardize their survival or future reproductive events. We assessed if reproductive tactics varied by maternal body mass and parity status in captive female white-tailed deer (Odocoileus virginianus) to determine if prime-aged mothers allocate relatively more resources to reproduction than primiparous mothers. Maternal body mass, not parity status, positively affected maternal allocation, with heavier mothers producing both heavy litters and heavy individual offspring. Conversely, maternal body mass alone did not affect litter size, rather the interaction between maternal body mass and parity status positively affected litter size such that maternal body mass displayed a greater effect on litter size for primiparous than multiparous mothers. Our results suggest that heavy white-tailed deer mothers allocate additional resources to current year reproduction, which may be an adaptation allowing mothers to produce high-quality litters and increase their annual reproductive success because survival to the next reproductive attempt is not certain.

scholarly journals Arachnid aloft: directed aerial descent in neotropical canopy spiders

2015 ◽  
Vol 12 (110) ◽  
pp. 20150534 ◽  
Author(s):  
Stephen P. Yanoviak ◽  
Yonatan Munk ◽  
Robert Dudley
Keyword(s):  
Surface Area ◽  
Body Mass ◽  
Tropical Rainforest ◽  
Wing Loading ◽  
Tree Crowns ◽  
Selective Pressures ◽  
Terrestrial Arthropods

The behaviour of directed aerial descent has been described for numerous taxa of wingless hexapods as they fall from the tropical rainforest canopy, but is not known in other terrestrial arthropods. Here, we describe similar controlled aerial behaviours for large arboreal spiders in the genus Selenops (Selenopidae). We dropped 59 such spiders from either canopy platforms or tree crowns in Panama and Peru; the majority (93%) directed their aerial trajectories towards and then landed upon nearby tree trunks. Following initial dorsoventral righting when necessary, falling spiders oriented themselves and then translated head-first towards targets; directional changes were correlated with bilaterally asymmetric motions of the anterolaterally extended forelegs. Aerial performance (i.e. the glide index) decreased with increasing body mass and wing loading, but not with projected surface area of the spider. Along with the occurrence of directed aerial descent in ants, jumping bristletails, and other wingless hexapods, this discovery of targeted gliding in selenopid spiders further indicates strong selective pressures against uncontrolled falls into the understory for arboreal taxa.

Scaling of anaerobic energy metabolism during tail flipping behaviour in the freshwater crayfish, Cherax destructor

1999 ◽  
Vol 50 (2) ◽  
pp. 183 ◽  
Author(s):  
J. Baldwin ◽  
A. Gupta ◽  
X. Iglesias
Keyword(s):  
Intracellular Ph ◽  
Body Mass ◽  
Arginine Kinase ◽  
Anaerobic Capacity ◽  
Glycolytic Enzyme ◽  
Time To Exhaustion ◽  
Freshwater Crayfish ◽  
Positive Allometry ◽  
Ph Buffering ◽  
Cherax Destructor

The allometry of anaerobic metabolism during escape behaviour was examined in the freshwater crayfish, Cherax destructor. Exercise time to exhaustion, and the total number of tail flips, increased with body mass. Concentrations of arginine phosphate and glycogen in the tail musculature of resting-state animals were independent of body mass, as was glycogen concentration following exercise to exhaustion. Lactate produced during exhaustive exercise, and intracellular pH buffering capacity, showed positive allometry. Activities of phosphorylase, phosphofructokinase and lactate dehydrogenase in the tail musculature showed positive allometry, while arginine kinase activity was independent of body mass. The positive allometry of anaerobic scope, reflected in the scaling of glycolytic enzyme activities, scales with the increased power required by larger animals to overcome drag during locomotion through water. The increased capacity for anaerobic muscle work in larger animals scales with anaerobic glycolytic capacity, while the contribution from phosphagen hydrolysis remains constant. Limits to anaerobic capacity are not set by fuel stores, but may involve inhibition of glycolytic enzymes at low pH, and the scaling of intracellular pH buffering. The positive allometry of anaerobic capacity observed for enforced exercise may not be used routinely in nature because of metabolic constraints imposed during recovery.

scholarly journals Weapons Evolve Faster Than Sperm in Bovids and Cervids

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1062
Author(s):  
Charel Reuland ◽  
Leigh W. Simmons ◽  
Stefan Lüpold ◽  
John L. Fitzpatrick
Keyword(s):  
Sexual Selection ◽  
Evolutionary Rates ◽  
Comparative Approach ◽  
Relative Importance ◽  
Reproductive Competition ◽  
Evolutionary Patterns ◽  
Fitness Consequences ◽  
Competing Demands ◽  
Before And After ◽  
Weapon Development

In polyandrous species, males face reproductive competition both before and after mating. Sexual selection thus shapes the evolution of both pre- and postcopulatory traits, creating competing demands on resource allocation to different reproductive episodes. Traits subject to strong selection exhibit accelerated rates of phenotypic divergence, and examining evolutionary rates may inform us about the relative importance and potential fitness consequences of investing in traits under either pre- or postcopulatory sexual selection. Here, we used a comparative approach to assess evolutionary rates of key competitive traits in two artiodactyl families, bovids (family Bovidae) and cervids (family Cervidae), where male–male competition can occur before and after mating. We quantified and compared evolutionary rates of male weaponry (horns and antlers), body size/mass, testes mass, and sperm morphometrics. We found that weapons evolve faster than sperm dimensions. In contrast, testes and body mass evolve at similar rates. These results suggest strong, but differential, selection on both pre- and postcopulatory traits in bovids and cervids. Furthermore, we documented distinct evolutionary rates among different sperm components, with sperm head and midpiece evolving faster than the flagellum. Finally, we demonstrate that, despite considerable differences in weapon development between bovids and cervids, the overall evolutionary patterns between these families were broadly consistent.

scholarly journals Population Density and Temperature Influence the Return on Maternal Investment in Wild House Mice

2021 ◽  
Vol 8 ◽  
Author(s):  
Nina Gerber ◽  
Yannick Auclair ◽  
Barbara König ◽  
Anna K. Lindholm
Keyword(s):  
Population Density ◽  
Body Mass ◽  
Early Life ◽  
Maternal Investment ◽  
The Body ◽  
Lifetime Reproductive Success ◽  
House Mice ◽  
Mus Musculus Domesticus ◽  
Sexual Competition ◽  
Survival And Reproduction

In mammals, reproduction is influenced by sexual competition, temperature and food availability and these factors might be crucial already during early life. Favorable early life environment and high maternal investment are expected to improve survival and reproduction. For example, in mammals, maternal investment via lactation predicts offspring growth. As body mass is often associated with fitness consequences, females have the potential to influence offspring fitness through their level of investment, which might interact with effects of population density and temperature. Here, we investigate the relationship between house mouse (Mus musculus domesticus) pup body mass at day 13 (used as approximation for weaning mass) and individual reproductive parameters, as well as longevity, under natural variation in population density and temperature (as approximation for season). Further, we assessed the extent to which mothers influence the body mass of their offspring until weaning. To do so, we analyzed life data of 384 house mice from a free-living wild commensal population that was not food limited. The mother’s contribution accounted for 49% of the variance in pup body mass. Further, we found a complex effect of population density, temperature and maternal investment on life-history traits related to fitness: shorter longevity with increasing pup body mass at day 13, delayed first reproduction of heavier pups when raised at warmer temperatures, and increased lifetime reproductive success for heavier pups at high densities. Our study shows that the effects of maternal investment are not independent of the effects of the environment. It thus highlights the importance of considering ecological conditions in combination with maternal effects to unravel the complexity of pup body mass on fitness measures.

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