Hind Body Research Articles

PERIPHERAL RESISTANCE RESPONSE TO OCCLUSION OF VISCERAL ARTERIES.

AbstractIn order to compare the effect of visceral and carotid sinus hypotension on the resistance vessels the peripheral resistance in 3 areas (hind body, kidneys and head) in the cat has been investigated by means of the constant perfusion rate technique during occlusion and desocclusion of visceral (coeliac, superior mesenteric and renal) arteries and of the carotid arteries. In all 3 areas clamping of the visceral arteries provoked a vasodilatation whereas a vasoconstriction in the hind body and kidney was observed during carotid artery occlusion. The clampings always produced significant rises in the general arterial blood pressure. The pressor response caused by visceral artery occlusion thus is produced in spite of a widespread dilatation of the resistance vessels—not as a consequence of a constriction in the same vessels. Denervation of the carotid sinuses plus section of the vago‐sympathetic trunks nearly always abolished the vasodilatation. Stabilising the blood pressure by means of a compensating device always abolished the vasodilatation during visceral artery occlusion. Under these circumstances the vasodilatation was not replaced by a vasoconstriction in the periphery. It has thus not been possible to demonstrate baroreceptor activity in the visceral arteries even under circumstances where the activity of the sino‐cardio‐aortic baroreceptor reflexes was eliminated.

On the functional morphology of a new fauna of Monogenoidea on fishes from Trivandrum and environs Part II. Opisthogynidae fam.nov. (Gastrocotyloidea) and Abortipedinae subfam.nov. (Protomicrocotyloidea)

On the functional morphology of a new fauna of Monogenoidea on fishes from Trivandrum and environs Part II. Opisthogynidae fam.nov. (Gastrocotyloidea) and Abortipedinae subfam.nov. (Protomicrocotyloidea)

Aggressiveness, Territoriality, and Sexual Behavior in Field Crickets (Orthoptera: Gryllidae)

AbstractMost contacts between adult male field crickets involve aggressive behavior by one or both individuals and terminate with the obvious retreat of one individual. Aggressive behavior consists of one or more of several actions: in mild encounters there is either rearing of the forebody, lashing of the antennae, and shaking of the body, or else rearing of the hind body, kicking with the hind legs, and shaking of the body; in intense encounters, antennal lashing and rearing of the forebody are followed by spreading the mandibles, stridulating distinctively, rushing forward, sparring with the forelegs, butting with the head, and grappling, wrestling, or biting with the mandibles. A male is often flipped back or thrown sideways, but mutilation as a result of fighting is rare, and only in the most intense encounters is the winner determined by what seems to be superior strength or fighting ability. The outcomes of most encounters are determined by the relative tenacity of the two males, and the intensity of aggression exhibited is correlated with the length of the fight, continued aggressive activity developing into increasingly severe combat until one male finally retreats. Groups of adult male field crickets caged in small arenas form essentially linear dominance hierarchies which are stable for short periods of time and which can be described in terms of several characteristics: (1) each male dominates all or nearly all of his encounters with males below him in the hierarchy, (2) the total number of encounters by individual males decreases gradually toward the bottom of the hierarchy, (3) the intensity of aggression exhibited during encounters decreases more or less gradually toward the bottom of the hierarchy and the numbers of no-decision and no-aggression encounters and actively homosexual contacts increase, and (4) encounters between males which rank next to each other are usually more intense than encounters between males which are far apart in the hierarchy.

A METHOD FOR THE ASSESSMENT OF THE NUTRITIONAL STATUS OF WILD UNGULATES

A study has been made of the relationship existing between heart girth and body weight and hind foot length and body weight of growing Columbian black-tailed deer (Odocoileus hemionus columbianus). From the results obtained, a method has been proposed for the assessment of the nutritional status of wild ungulates. This method involves a comparison of ratios of body weight estimated from heart girth to body weight estimated from hind foot length.

The Determination of Age of Nestling and Sub-Adult Gray Squirrels in West Virginia

The inspection of den trees, boxes and leaf nests in order to ascertain the peak parturition period of the gray squirrel, Sciurus carolinensis, has been undertaken by almost every investigator studying this species. Due to the difficulty in finding litters, none has published any work that can be used as a basis for age determination. The writer has found, however, the work of Monica Shorton (1951) in Great Britain to be outstanding. Table 1 is based on her work and the additional data on 68 nestling squirrels of varying ages collected during the present study. All data pertaining to nestling squirrels were collected on Seneca State Forest, located in the Allegheny Plateau Region of West Virginia. Data on the sub-adults (squirrels over 10 weeks old) were collected on Seneca and six other state forests and refuges located throughout the State. Fifty-one nestlings (19 litters) were checked once, nine (three litters) twice, six (two litters) four times and two (one litter) six times. The checks were made at intervals of one to three weeks. Repeated visits were made to all litter sites, but in the majority of cases the litters were not present the second time. Data were also collected from nestlings born in captivity. In these cases the mother usually devoured her young after they had been handled several times. Notes were taken on the condition of the pelage, eyes, ears and teeth at each examination. Measurements of the hind foot, body and tail length were also taken and each squirrel was weighed. While the key was developed on the basis of the data obtained from the squirrels found in the spring and summer of 1953, it was applied again to the squirrels found during the spring of 1954. Some corrections and additions were made after the latter check. It was found that the key applied in the majority of cases, but occasionally one of the characteristics would not fall in the same age class as the others; however, in most instances, five of the seven criteria were valid. Spring litters in 1954 were larger than in 1953. It was found that one runt was present in the majority of cases where there were four squirrels in the litter. Data on these runts were not used in devel-