摘要:

The duration of poststrike elevation in tongue-flicking (PETF) in the savannah monitor,Varanus exanthematicus, is experimentally estimated to be at least 25 min, with some residual increase persisting for at least 30 min. This is by far the most prolonged PETF yet observed in a lizard, as predicted from the active foraging on mobile prey and the chemosensory specializations of the varanid tongue. PETF is shorter than in rattlesnakes, presumably because prolonged search is more likely to be successful when the prey has been envenomated. Strike-induced chemosensory searching, which consists of both PETF and searching movements, appears to be of shorter dutation than PETF because searching movements do not last as long as PETF. Individual lizards differ markedly in the duration of tongue-flicking and the degree of increase in tongueflicking attributable to biting prey. Individuals tongue-flick at their own highest rates in the first minutes after stimulus presentation, then show a decline, often to zero. Some individuals resume tongue-flicking, sometimes at high rates, after having stopped for one to several minutes. Such behavior may aid in relocation of escaped prey that has reemerged after the initial chemosensory search has failed or in location of similar prey likely to be in the vicinity if patchily distributed. Methods of analyzing data on duration of PETF are considered.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523112

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

FemaleMacrodactylus costulatus,sericinus, andsylphismated repeatedly while feeding on flowers and fruits as they matured eggs. Courtship in all species occurred both prior to and following intromission, with most courtship being performedafterthe male had achieved intromission. Females often prevented males from mounting, and often prevented mounted males from achieving intromission. They also probably often prevented male genitalia from penetrating past the vulva, even after they had allowed them into the genital chamber. Males at least sometimes pushed forcefully at structures both on the surface of the female and within her reproductive tract. Copulation probably involved a combination of force and persuasion. It often failed to result in complete transfer of sperm. Males displayed striking virtuosity in both the morphology and behavior of their genitalia, which assumed at least four different morphological configurations. At least five and perhaps up to eight different functions were performed by male genitalia. Small sacs near the tips of the male parameres were probably used by males as “foot-in-the-door” devices to gain access to the female's genital chamber, while the spiney collar and tongue may have helped open the vulva to allow deeper penetration. The energetic and persistent courtship which occurred after intromission was achieved may lunction at least partly to induce the female to allow the male to reach the deeper stage of penetration necessary for spermatophore formation, and perhaps to permit transfer of sperm to her spermathecal duct. Male courtship behavior included movements of his head, vibration and sweeping movements of his middle legs, rubbing with his abdominal bristles against the female's elytra, strong substrate vibrations of unknown origin in the male's body, and tapping and stroking with his genitalia on the external surface of the female's abdomen while he held her with his specialized front legs. Pairings in the field lasted up to several days, but there was no sign of size biases in either paired males or females. Males were more susceptible to predation by a common predator than were females when beetles were paired.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523113

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Six colony (CM) and six individually reared males (IM), aged 7 to 8 months, were singly introduced into unfamiliar colonies of conspecifics for a period of 30 days. CM easily adjusted to the new social situation: on the 1st day they explored the new environment but did not court any female thereby avoiding attacks from the male residents. In the course of the following days they gradually integrated into the social network of the established colonies and could even gain higher ranking social positions than those which they had had in their natal colonies. On the CM 1st, 3rd, 6th, 10th and 20th day in the new colonies, changes could not be determined in either their body weights or in their plasma concentrations of glucocorticoids, androgens and norepinephrine. In contrast, IM responded to the new situation with substantial decreases in body weight as well as with extreme increases in plasma glucocorticoid concentrations. We conclude that CM, in comparison to IM, can integrate well into strange colonies because they acquire appropriate behaviour through rearing in their natal colonies.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523114

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Males of the coreid bug,Margus obscurator(F.), were individually numbered in the field in southeastern Georgia (USA) and censused daily for the 6 weeks in spring from the initiation of mating activity until the complete decline of the adult population. Data was analyzed for the subset of males sighted at least 5 times since the relationship between number of observations and variance in mating success leveled off at five observations. Variance in male mating success exceeded that generated by null models, suggesting a phenotypic determinant of mating success. Body length was significantly positively correlated with male mating success. Longer males were more likely to retain a grasp on females which resist, by fleeing, most courting males. The intensity of sexual selection (standardized selection differential) on male size was greater in the second half of the season (0.43 versus 0.21) when both host plant abundance and the proportion of females in the population had declined. Consequently, male density and the number of intermale aggressive interactions increased. During fights, larger males were more likely to retain access to females or the flower heads on which mating occurred. The opportunity for sexual selection (= squared coefficient of variation for mating success) was also greater in the second half of the season (0.90 versus 0.20). The opportunity for sexual selection increased 2.5 times faster than the intensity of sexual selection on size between halves of the season, reflecting the greater male-bias in the operational sex ratio (proportion of males = 0.57 versus 0.49), a more patchy distribution of females and, perhaps, reflecting the operation of additional components of phenotypic selection.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523115

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The aim of this paper is the study of the inherited directional tendency in sandhoppers and its reaction norm, analyzing two of its components, the reaction to releasing stimuli and the phototactic response. Young experienced (wild) and inexperienced (laboratory-born) specimens ofTalitrus saltator(Montagu 1808) were tested singly and repeatedly in a test arena under the sun on dry and wet substrates, and in the laboratory with monochromatic artificial lights (blue and yellow-green). The directional tendency towards the home-sea of laboratoryborn individuals in response to a dry substrate improved with successive trials while wild sandhoppers responded promptly and were more concentrated seawards. On the other hand, the innate directional tendency towards land on a wet substrate, demonstrated here for the first time in Mediterranean talitrids, did not change with experience. Tested with monochromatic lights, the laboratory- born individuals reacted in the main photopositively, but tended to change their reactions after the first trial; wild individuals showed a stronger reaction to the light and, in some cases, tended to orient photomenotactically. The reaction of both laboratory-born and wild sandhoppers was stronger in respect to blue than to yellow-green light.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523116

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Sand goby males guarding eggs from one female without access to food lost 13.9% of their body weight over a caring period of 10 days. This was more than twice the body weight lost by non-guarding males, who had nests but no eggs (weight loss 5.8%). Caring for the eggs therefore imposes an energetic cost on the male. Egg losses in the field were on average 3.3% of the egg mass. Males with egg losses were on average smaller than males without losses and they also had smaller egg masses. If a male was removed and his nest taken by a new male, 31.0 to 100.0% of the original eggs were eaten within 24 hr. In guarding males we never observed hetero-cannibalism. The proportion of time a male spent fanning was positively correlated to his standard length, larger males spending more time fanning. It is concluded that larger males are better fathers.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523117

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

During the breeding seasons 1985–1986, we studied the daily activity of adult bee-eaters by direct observations at four nests and by automatic recordings of three nests. During the digging and incubation phases, the adults' movements were scarce and concentrated during the morning, but in the chick-rearing stage they were high and reached a peak at noon and in the early afternoon. Among nests there were significant differences in the amount of adults' movements during all the breeding phases. The start of daily activity and the rate of the adults' movements to the nests were strongly related to air temperature.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523118

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The present study investigates the prediction that, given the energy-intensive nature of male courtship and rutting behavior in mule deer, bucks will preferentially mate with those does most likely to breed successfully. Does without fawns in a given breeding season are in better physical condition and are more likely to rear fawns conceived in the current breeding season than are does with fawns. In those cases where both categories of females were present, significantly more courtship behaviors were directed towards does without fawns than towards does with fawns. The consequences of such a choice by bucks are discussed.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523119

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Groups of experimentally naive Swiss mice, 20 days old, were exposed to a varying quality of socially transmitted information needed to solve a food-finding problem. The problem consisted of opening a rotating door of an apparatus. Mice that lived with a demonstrator opening the apparatus and mice that lived with an adult manipulating but not opening the apparatus were the most efficient animals in solving the problem. In addition other groups of mice had different non-social experiences with the problem. The data indicate that these animals did not improve their ability in performing the task compared with control animals. In essence the present results suggest that mice were capable of learning aspects of the opening techinque by social learning rather than by trial and error.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523120

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Created from animals: the moral implications of Darwinism. By James Rachels. ISBN 0-19-117775-3, 1990, 145 pp., price £ 17.50 in UK.

ISSN:0394-9370    

DOI:10.1080/08927014.1993.9523121

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor