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Changes In Absorptive Surfaces Of Rat Visceral Yolk Sac With Increasing Gestational Age, W. P. Jollie May 1986

Changes In Absorptive Surfaces Of Rat Visceral Yolk Sac With Increasing Gestational Age, W. P. Jollie

Scanning Electron Microscopy

The free surface of the endodermal epithelial lining of the rat visceral yolk sac was examined by scanning electron microscopy at three stages of pregnancy, viz., 12, 17 and 22 days (birth typically occurring on the 23rd day). Additionally, by ultrasonic vibration of tissues that had been subjected to prolonged osmium fixation, the epithelium was removed and such microdissected membranes similarly were examined.

With increasing gestational age the free surface of the epithelium. underwent a relative increase in absorptive area by three mechanisms: formation of increasingly complex villous projections of the visceral yolk sac as a whole, a doming of …


Weighted Silks Observed Using Energy Dispersive X-Ray Spectrometry, M. Ballard, R. J. Koestler, N. Indictor May 1986

Weighted Silks Observed Using Energy Dispersive X-Ray Spectrometry, M. Ballard, R. J. Koestler, N. Indictor

Scanning Electron Microscopy

A group of modern silk fabrics was treated with various weighting agents as standards. These standards were observed using energy dispersive x-ray spectrometry. The standards were compared to untreated samples and to museum specimens of weighted silks. In all prepared specimens the elements expected from treatment were observed; weighting treatments could be distinguished. The analytical procedures are discussed and compared to recent work on mordant analysis using the same techniques.


Elemental And Ultrastructural Characteristics Of The Egg Capsules Of Nautilus Pompilius, R. J. Koestler, E. D. Santoro, G. Dingerkus May 1986

Elemental And Ultrastructural Characteristics Of The Egg Capsules Of Nautilus Pompilius, R. J. Koestler, E. D. Santoro, G. Dingerkus

Scanning Electron Microscopy

Six pearly nautili (Nautilus pompilius) raised in captivity produced nonviable egg capsules which were examined using scanning electron microscopy ( SE M) and energy dispersive x-ray spectrometry (EDS). Macro and microscopic observations revealed two distinct and separate walls encircling the yolk sac. Both walls exhibited a porous appearance in cross-section. Protein analysis demonstrated the proteinaceous nature of nidimental gland secretions and egg capsule walls.

EDS analysis of each wall shows the elemental composition to be identical in both, with each wall containing similar proportions of S, CI, Mg, Na, K, and trace amounts of Ca. X-ray mapping of Na and …


Application Of Scanning Electron Microscopy To The Study Of Shark Dermal Denticles, G. Dingerkus, R. J. Koestler May 1986

Application Of Scanning Electron Microscopy To The Study Of Shark Dermal Denticles, G. Dingerkus, R. J. Koestler

Scanning Electron Microscopy

Clear, high resolution scanning electron micrographs of shark dermal denticles are essential to allow the study of their morphology and micro-relief. Various techniques were tried to remove mucus and adventitious debris, including KOH, trypsin enzyme, and ultrasonication. In most species examined the best results were obtained with enzyme treatment followed by ultrasonication. For scanning electron microscopic examination it was found that 15 nm gold coating, or more, and 10 kV, or less, had to be employed to reduce charging of the denticles.


Urolithiasis In A Patient Ingesting Pure Silica: A Scanning Electron Microscopy Study, D. B. Leusmann, J. Pohl, G. Kleinhans May 1986

Urolithiasis In A Patient Ingesting Pure Silica: A Scanning Electron Microscopy Study, D. B. Leusmann, J. Pohl, G. Kleinhans

Scanning Electron Microscopy

A patient who repeatedly produced urinary calculi, had consumed about 3g of cristobalite (SiO2) per day for many years. Investigations using scanning electron microscopy revealed minute particles containing silicon in the core of the stone as well as in urine sediment. A mechanism similar to that proposed for the effect of silicon-containing drugs against gastric ulcer, may play a role in this formation of silicon-containing urinary stones.


Quantitative Vascular Casting Of The Post-Ischemic Hydronephrotic Kidney, Vincent H. Gattone Ii, Robert D. Sale May 1986

Quantitative Vascular Casting Of The Post-Ischemic Hydronephrotic Kidney, Vincent H. Gattone Ii, Robert D. Sale

Scanning Electron Microscopy

The renal microvasculature (afferent arteriole) and glomeruli were examined and quantitated by two methods in the post-ischemic hydronephrotic (PIH) kidney. The methods used were: 1) an in vivo examination and 2) controlled perfusion-fixation, quantitative vascular casting examined by scanning electron microscopy. The second method was also applied to the vasculature of the contralateral, functional kidney. The goals of the study were to: 1) validate the quantitative vascular casting method by comparing PIH renal microvascular data from the casting method with in vivo values and 2) determine the extent of microvascular dimensional difference of the PIH kidney from its contralateral functional …


Lack Of Regional Surface Differences In Mouse Bladder Urothelium: A Scanning Electron Microscopic Study, Kari Feren, Jon B. Reitan May 1986

Lack Of Regional Surface Differences In Mouse Bladder Urothelium: A Scanning Electron Microscopic Study, Kari Feren, Jon B. Reitan

Scanning Electron Microscopy

The surface structures of mouse urinary bladder epithelium, the urothelium, were examined in SEM. The entire surface area of both a moderately and a well stretched bladder were studied. No regional differences were found in either case. The moderately stretched bladder showed deep folds, while the well stretched bladder had only small folds giving the bladder an accordion-like appearance. In both bladders the typical surface structures were microridges arranged in a honeycomb-like pattern. The present study indicates that focal or regional differences found in bladders treated with chemicals or exposed to radiation are a result of the treatment itself, and …


Scanning Electron Microscopy Of The Irradiated Mouse Bladder Urothelium, Jon B. Reitan, Kari Feren May 1986

Scanning Electron Microscopy Of The Irradiated Mouse Bladder Urothelium, Jon B. Reitan, Kari Feren

Scanning Electron Microscopy

The luminal surface of mouse bladder urothelium was studied by scanning microscopy 1 year after irradiation with 0, 10 and 20 Gy respectively. The controls that were anaesthetized only displayed surface characteristics indistinguishable from normal urothelium.

Irradiation with 10 Gy did not result in marked overall changes in the scanning electron microscopic features of the luminal aspect, but in some areas alterations comparable to the alterations after 20 Gy were observed. After irradiation with 20 Gy focal hyperplastic areas, superficial early ulceration and dedifferentiation of cover cells were seen. The dedifferentiation to featureless cells is probably not associated with increased …


Effect Of Ethanol On Thermoregulation In The Goldfish Carassius Auratus, Candace Sharon O'Connor May 1986

Effect Of Ethanol On Thermoregulation In The Goldfish Carassius Auratus, Candace Sharon O'Connor

Dissertations and Theses

In an attempt to elucidate the mechanism by which ethanol affects vertebrate thermoregulation, the effect of ethanol on temperature selection was studied in the goldfish, Carassius auratus. Ethanol was administered to 10 to 15 g fish by mixing it in the water of a temperature gradient. The dose response curve was very steep between 0.5% (v/v) ethanol (no response) and 0.7% (significant lowering of selected temperature in treated fish). Fish were exposed to concentrations of ethanol as high as 1.7%, at which concentration most experimental fish lost their ability to swim upright in the water. At concentrations higher than …


Preparation Methods For Quantitative Electron Probe X-Ray Microanalysis Of Rat Exocrine Pancreas: A Review, N. Roos, T. Barnard May 1986

Preparation Methods For Quantitative Electron Probe X-Ray Microanalysis Of Rat Exocrine Pancreas: A Review, N. Roos, T. Barnard

Scanning Electron Microscopy

Pancreatic acinar cells are thought to secrete a fluid containing digestive enzymes and electrolytes and use e,g, calcium as a second messenger upon stimulation, Together with their pronounced morphological polarity, they provide a model system to study the effect of different preparation methods for quantitative biological electron probe X-ray microanalysis (EPXMA) of ultrathin sections, Several preparation methods i,e,, freeze-drying and plastic-embedding, freeze-substitution (2 days) and freeze-drying of ultrathin cryosections have been applied to examine the retention of sodium, magnesium, phosphorus, sulfur, (chlorine), potassium and calcium in subcellular compartments (basal cytoplasm, apical cytoplasm, mitochondria and zymogen granules), In freeze-substituted samples the …


Corrosion Cast Technique Applied In Lymphatic Pathways, A. Castenholz May 1986

Corrosion Cast Technique Applied In Lymphatic Pathways, A. Castenholz

Scanning Electron Microscopy

The paper deals with methods and results of the microcorrosion cast technique in lymph angiology. For the representation of the special organization of the lymph vascular system including the initial vascular structures, intranodal pathways, bigger collectors, and lymph trunks, the application of various injection techniques is necessary. The interstitial injection of Mercox proves to be suitable to show the initial lymphatics and prelymphatic spaces. Similarly, the intranodal injection makes visible the system of the lymph sinuses and the spaces of the reticular tissue in this organ. Casts of bigger collecting vessels, lymph trunks, and thoracic duct can be obtained by …


The Study Of Biominerals By High Resolution Transmission Electron Microscopy, Stephen Mann May 1986

The Study Of Biominerals By High Resolution Transmission Electron Microscopy, Stephen Mann

Scanning Electron Microscopy

This paper presents an overview of the study of the ultrastructure of biogenic inorganic solids (biominerals) using high resolution transmission electron microscopy (HRTEM). A range of biominerals have been studied including iron oxides, calcium phosphates, calcium carbonates and silica. The studies have revealed information concerning the structural complexity of these materials and have identified crystallographic order and disorder at the nanometre level. In addition, the results have aided the elucidation of the mechanisms of nucleation and growth of biogenic minerals.


Bird Use Of Lakes In The Claremont-Upland Area, Valerie Banschbach May 1986

Bird Use Of Lakes In The Claremont-Upland Area, Valerie Banschbach

Pomona Senior Theses

I studied water bird use of two lakes in the Claremont-Upland area to determine what physical, chemical, and biological aspects of these lakes provide suitable water bird habitat and food resources. I censused the Bernard Field Station Lake in Claremont and a gravel pit freshwater area in Upland from 10/85 to 3/86 for water bird use. I also mapped these sites, noted their water surface area and water depth changes, monitored their water chemistry, and censused their vegetation. The results of this work showed more total water birds per hour of observation time, and more birds per hour of observation …


Life History And Production Of Three Species Of Isopods In Beargrass Creek Louisville, Ky, James A. Eckstein May 1986

Life History And Production Of Three Species Of Isopods In Beargrass Creek Louisville, Ky, James A. Eckstein

Electronic Theses and Dissertations

The life history and annual production of the aquatic isopods L. fontinalis, C. intermedia and C. brevicaudus in a spring stream, Beargrass Creek, Louisville, Kentucky was studied. Reproductive activity was observed with the greatest intensity in the spring months from March to May. Smaller secondary peaks for recruitment of young were seen in the fall months for L. fontinalis and C. intermedia. Brood size for the three isopods was compared by linear regression. The mean annual biomass for the three isopods ranged from 0.67 g/m2 for C. intermedia, 0.83 g/m2 for C. brevicaudus to 2.1 g/m2 for L. fontinalis. Annual …


Effect Of High-Intensity Exercise Training On Functional Capacity Of Limb Skeletal Muscle, John Patrick Troup, Joseph Mark Metzger, Robert H. Fitts May 1986

Effect Of High-Intensity Exercise Training On Functional Capacity Of Limb Skeletal Muscle, John Patrick Troup, Joseph Mark Metzger, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The purpose of this study was to determine whether a program of regular sprint exercise training alters the functional properties or protects against the development of fatigue in fast- and slow-twitch rat skeletal muscle. The training program consisted of 6 sprints of 4.5-min duration at 40 m/min and 15% slope with 2.5-min rest intervals, performed 5 days/wk for 6 wk. The exercise program significantly increased (P-1·min-1) in the predominantly type I soleus (SOL) from 28 ± 2 to 44 ± 2; the type IIb superficial region of the vastus lateralis (SVL) from 10 ± 1 to 16 ± …


Contractile And Biochemical Properties Of Diaphragm: Effects Of Exercise Training And Fatigue, Joseph Mark Metzger, Robert H. Fitts May 1986

Contractile And Biochemical Properties Of Diaphragm: Effects Of Exercise Training And Fatigue, Joseph Mark Metzger, Robert H. Fitts

Biological Sciences Faculty Research and Publications

The effect of high-intensity trained (6 X 4.5 min at 40 m/min, 15% grade, 2.5-min rest between bouts, 5 days/wk, for 6 wk) on contractile, biochemical, and fatigue properties of the rat diaphragm were examined. The exercise program produced significant elevations in the mitochondrial marker enzyme citrate synthase (µmol·X·g-1·X min-1) in the soleus (SOL) (27.2 ± 1.5 vs. 46.7 ± 2.4; mean ± SE), deep vastus lateralis (DVL) (40.8 ± 2.6 vs. 58.3 ± 2.8), and superficial vastus lateralis (SVL) (8.5 +/- 0.6 vs. 11.4 +/- 0.7). No significant differences were observed in the crural (CRU) …


Viruses In Water, Nasrin Mohammadpour Daryaee May 1986

Viruses In Water, Nasrin Mohammadpour Daryaee

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The use of water by man, plants and animals is universal. Without it there can be no life. Every living thing requires water. Man can live nearly two months without food, but can live only three or four days without water. In our homes, whether in the city or in the country, water is essential for cleanliness and health. Water can be considered as the principal raw material and the lowest cost raw material from which most of our farm produce is made. It is essential for the growth of crops and animals and is a very important factor in …


Purification Of Anthrax Toxin Protective Antigen Component And Characterization Of Its Binding Interaction With Bovine Kidney Cells, Daniel Dalton Martin May 1986

Purification Of Anthrax Toxin Protective Antigen Component And Characterization Of Its Binding Interaction With Bovine Kidney Cells, Daniel Dalton Martin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Protective antigen component of B. anthracis toxin was produced and purified to the >99% level. Toxin was purified from culture supernatant utilizing concentration and liquid chromatography techniques. Purity was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

The purified protective antigen retained biological and antigenic activity as evidenced respectively by lethality in Fischer 344 rats when injected in combination with lethal factor, and by positive results on the Ouchterlony double diffussion assay.

Radioiodinated protective antigen was used both in the in vivo and the in vitro experiments.

In vivo distribution of labelled protective antigen was determined in Fischer 344 rats. Assay …


Functional Aspects Of Renal Glomeruli Based On Scanning Electron Microscopy Of Corrosion Casts, With Special Emphasis On Reptiles And Birds, H. Ditrich, H. Splechtna Apr 1986

Functional Aspects Of Renal Glomeruli Based On Scanning Electron Microscopy Of Corrosion Casts, With Special Emphasis On Reptiles And Birds, H. Ditrich, H. Splechtna

Scanning Electron Microscopy

The glomerular complexity of several species of birds and reptiles is investigated in this study by scanning electron microscopy of vascular corrosion casts. Comparing these results with those of a freshwater teleost and a mammalian species, a trend towards small, simple glomeruli of the avian type, beginning with large, well vascularized glomeruli resembling the type found in fish, can be observed in reptiles.

A close correlation between glomerular size and habitat can be established comparing related species having a similar physiological mode of renal function.

Entirely different from this sauropsidian evolutionary line of development is the highly complex, large differentiation …


Technical Parameters Of Plastics (Mercox Cl-2b And Various Methylmethacrylates) Used In Scanning Electron Microscopy Of Vascular Corrosion Casts, T. Weiger, A. Lametschwandtner, P. Stockmayer Apr 1986

Technical Parameters Of Plastics (Mercox Cl-2b And Various Methylmethacrylates) Used In Scanning Electron Microscopy Of Vascular Corrosion Casts, T. Weiger, A. Lametschwandtner, P. Stockmayer

Scanning Electron Microscopy

The most frequently used resins for vascular corrosion casting Mercox Cl-2B, Mercox Cl-2B diluted with methylmethacrylate (MMA) monomer and various self prepared MMA and hydroxyproyl-methacrylate mixtures were tested with regard to their thermostability, shrinkage, viscosity and replication quality. It was found that tempering of the plastics improves their thermostability with the exception of Mercox Cl-2B and that shrinkage depends on the amount of monomers a resin contains. In detail; Mercox Cl-2B has the lowest shrinkage (8.018%) whereas a hydroxypropyl-methacrylate mixture possessed the highest (20.408%). But, on the other hand, viscosity decreases with the quantity of monomers. All resins tested were …


Scanning Electron Microscopic Studies On Microvascular Architecture Of Human Coronary Vessels By Corrosion Casts: Normal And Focal Necrosis, T. Ono, Y. Shimohara, K. Okada, S. Irino Apr 1986

Scanning Electron Microscopic Studies On Microvascular Architecture Of Human Coronary Vessels By Corrosion Casts: Normal And Focal Necrosis, T. Ono, Y. Shimohara, K. Okada, S. Irino

Scanning Electron Microscopy

Microvascular architecture of the normal human heart and myocardial focal necrosis were studied by scanning electron microscopy of corrosion casts. Casts macroscopically identical in form to the left ventricular posterior wall were prepared.

The following results were obtained in the normal human heart. (I) Most of the arterioles communicated with capillary plexuses smoothly and straight forwardly in the left ventricular posterior free wall. (2) Arterioles which branched from the arteries ran in various directions and continued into capillaries either at right angles or obliquely in the trabeculae carneae. (3) capillaries running parallel with the cardiac muscle fibers ran in different …


A Summary Of Ion Beam Etching Of Biological Material With Special Reference To The Saddle Field Source, D. Claugher Apr 1986

A Summary Of Ion Beam Etching Of Biological Material With Special Reference To The Saddle Field Source, D. Claugher

Scanning Electron Microscopy

A brief review of etching of biological materials using radio frequency, ion beam and electrostatic focused sources. Results of experiments using fast atom sources to dissect pollen, diatoms, protozoa and small arthropods, indicate that they produce a much smoother result which enables investigations to be carried out at high magnifications with the SEM.


Surface Studies Of Duodenal Lesions Induced By Thoracic Irradiation, K. E. Carr, S. Ellis, A. Michalowski Apr 1986

Surface Studies Of Duodenal Lesions Induced By Thoracic Irradiation, K. E. Carr, S. Ellis, A. Michalowski

Scanning Electron Microscopy

Acute duodenal ulcers are produced in mice as a remote ("abscopal") effect of irradiation to the lower mediastinum. Such lesions have been examined with scanning electron microscopy at 5, 8 and 28 days after irradiation with 18 Gy of X-rays. All the ulcers occur within the first 1 cm long segment of the duodenum which is endowed with Brunner's glands. The single lesions vary in size, shape and position. The damaged area often includes much of the duodenal circumference and is distinguished by conical or rudimentary villi, or even by the complete absence of villi. In contrast, around the periphery …


Exocytosis From Large Dense Cored Vesicles As A Mechanism For Neuropeptide Release In The Peripheral And Central Nervous System, Asa Thureson-Klein, Richard L. Klein, Pei-Chun Zhu Apr 1986

Exocytosis From Large Dense Cored Vesicles As A Mechanism For Neuropeptide Release In The Peripheral And Central Nervous System, Asa Thureson-Klein, Richard L. Klein, Pei-Chun Zhu

Scanning Electron Microscopy

Nerve terminals often contain morphological-distinct populations of large (75-110 nm) and small (45-55 nm) vesicles. The small vesicles are speculated to account for release of transmitter quanta as they accumulate at presynaptic membranes. Large vesicles can co-store neuropeptides and classical transmitters but their function in neurotransmission has been disputed because they do not appear to accumulate at chemical synapses. However, there is now evidence that the large vesicles play a role in neuro-transmission or its modulation even though they may not be eminently involved in synaptic release. Thus, exocytosis occurs along the synapse-lacking membranes of peripheral noradrenergic varicosities. Large vesicles …


Quantifying Spatial Patterns Of Overgrowth In Epibenthic Communities, David S. Wethey, Linda J. Walters Mar 1986

Quantifying Spatial Patterns Of Overgrowth In Epibenthic Communities, David S. Wethey, Linda J. Walters

Faculty Publications

A method is presented that allows rapid and accurate measurement of changes in the spatial pattern of space occupation in encrusting organisms. The boundaries of organisms are represented as polygons, and geometric difference calculations are used to establish the perimeters of the areas gained or vacated between sampling dates. The influence of interspecific interactions on occupation of space is also quantified: geometric intersection calculations are used to define the perimeters of the areas gained or lost in overgrowth interactions. A method is presented for estimating the sampling frequency necessary for detection of significant changes in occupation of space. The method …


Calcium And Cystic Fibrosis, Godfried M. Roomans Mar 1986

Calcium And Cystic Fibrosis, Godfried M. Roomans

Scanning Electron Microscopy

Cystic fibrosis (CF) is a generally lethal, congenital, genetic disease of unknown etiology. It is likely that a defective regulation of ion and water transport in exocrine glands and possibly also in other epithelial cells has a central role in the pathogenesis of this disease. Calcium has been implicated in the basic defect underlying CF because of findings of abnormally high calcium levels in some secreted fluids and some cells of CF patients.

Using X-ray microanalysis, we have demonstrated elevated calcium concentrations in cultured fibroblasts and in goblet cells of the bronchial epithelium of CF patients. A factor produced by …


Quantitative Renal Vascular Casting In Nephrology Research, Vincent H. Gattone Ii, Andrew P. Evan Mar 1986

Quantitative Renal Vascular Casting In Nephrology Research, Vincent H. Gattone Ii, Andrew P. Evan

Scanning Electron Microscopy

The present paper describes the use of a quantitative renal vascular casting method to study the changes associated with kidney disease. Several animal models of hypertension (spontaneously hypertensive rat, SHR, with its normotensive rat the Wistar Kyoto, WKY; Dahl salt sensitive DS - hypertensive, and salt resistant DR -normotensive) were examined at time points when the systemic blood pressure was rising (6 and 12 weeks of age) and following renal denervation (in SHR-WKY rats). The SHR appears to have a smaller caliber afferent arteriole at both 6 and 12 weeks of age. This difference is probably not entirely due to …


Plant Ultrastructure In The Scanning Electron Microscope, Susan H. Barnes, Stephen Blackmore Mar 1986

Plant Ultrastructure In The Scanning Electron Microscope, Susan H. Barnes, Stephen Blackmore

Scanning Electron Microscopy

Preparative techniques which have been used to study internal details of plant cells in the scanning electron microscope are reviewed. A number of methods have previously been described which involve selective extraction of materials from freeze-fractured surfaces and can be referred to as freeze-fracture and cytoplasmic maceration. One of these techniques which involves an extended period of cytoplasmic maceration with dilute osmium tetroxide has been applied to the study of Cichorium intybus (chicory) pollen ontogeny. The results obtained, including changes in the numbers of mitochondria and the form of endoplasmic reticulum during the course of development demonstrate the value of …


Atp-Dependent Formation And Motility Of Aster-Like Structures With Isolated Calf Brain Microtubule Proteins., Richard C. Weisenberg, Robert D. Allen, Shinya Inoue Mar 1986

Atp-Dependent Formation And Motility Of Aster-Like Structures With Isolated Calf Brain Microtubule Proteins., Richard C. Weisenberg, Robert D. Allen, Shinya Inoue

Dartmouth Scholarship

Microtubule proteins isolated from calf brain will undergo gelation-contraction in the presence of ATP. We have now examined this process by video-enhanced contrast microscopy. After ATP addition to steady-state microtubules, slow (1-5 micron/min), linear movements of particles and microtubules toward aggregation centers occur. The resulting structures resemble mitotic spindle asters. During the time when gel contraction occurs, asters move (at 1-5 micron/min) toward other nearby asters. This is accompanied by the apparent shortening of the microtubules running between the asters. This is the first example of isolated microtubules undergoing a process that has similarities to half-spindle shortening during anaphase A. …


Prezygotic Male Reproductive Effort In Insects: Why Do Males Provide More Than Sperm, James S. Quinn, Scott K. Sakaluk Mar 1986

Prezygotic Male Reproductive Effort In Insects: Why Do Males Provide More Than Sperm, James S. Quinn, Scott K. Sakaluk

Faculty Publications – Biological Sciences

Males' incentives for providing benefits to females and/or their offspring are ambiguous during the period prior to zygote formation. The benefits may function to increase the number of available eggs fertilized by a male and/or enhance the production and survival of his offspring. In some cases, male prezygotic investment may be an adaptation to secure fertilizations despite the fact that it incidentally benefits the female or her offspring. More often, the benefits to offspring production and survival are not simply incidental and probably account, in part, for the magnitude of the male investment. Regardless of the adaptive significance of male …