摘要:

Abstract and SummaryThe hypothesis that blacknose daceRhinichthys atratulusdiscriminate between piscivorous creek chubSemotilus atromaculatusand nonpiscivorous common suckersCatostomus commersoniwas tested in a seminatural, artificial stream. Dace avoided the nonpredatory suckers less than they did the predatory chub, which they avoided during both day and night. However, dace significantly avoided the nonpredator at night. Further, experienced and inexperienced dace avoided the nonpredator similarly, suggesting that they had not learned to discriminate predator from nonpredator in their natural habitat. These results are consistent with two hypotheses (1) that individuals varied in ability to discriminate predatory from nonpredatory fishes, and (2) that the predator was more active than the nonpredator, thereby “frightening” the dace more. At temperatures of<6°C the nonpredator was inactive and dace no longer avoided it at night, but continued to avoid the active chub, suggesting that movement constituted part of the avoidance‐releasing stimulus. Because dace avoided nonpredators, they may waste time in natural streams avoiding harmless fish. It is suggested that the dace cannot afford the risk of a mistaken identity, which may be high in the stream environment, and selection favors those that avoid all large, movin

ISSN:0044-3573    

DOI:10.1111/j.1439-0310.1984.tb01358.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract and SummaryWe examined the extent to which parental investment, as measured by brood defence, is determined by selection via life history in a short‐lived bird, the great tit (Parus major). Great tit parents tending 1st and 2nd broods of the season were used to test five predictions of a cost/benefit model of brood defence based on the species average demography. Thebenefitwas envisaged as the brood's contribution to a parent's fitness, and thecostas the potential loss if the defender dies in the act of defence; this loss was mirrored by Residual Reproductive Value plus a fraction of the brood dying as a consequence of the defender's death. Univariate and multivariate procedures were applied to six measures of defence response in 221 experimentally naive great tit pairs with nestlings. Stimuli consisted of a live raptor and a multi‐species taped mobbing chorus (both of which triggered strong alarm), the latter alone, and a novel, visual stimulus inhibiting nest visits for some time. As predicted by the model, response strength and associated risk increased with (1) advancing time in the breeding season, (2) the age of young, and (3) the number of young in 2nd broods. The last finding, being non‐trivial, is the strongest and the only unequivocal support for the notion that life‐history has moulded parental investment also in a short‐lived species; findings (1) and (2) could be alternatively accounted for by simply assuming that parents tailor their defence to environmental conditions permitting a new breeding episode. The model failed to predict the change of defence behaviour between 1st and 2nd broods. Instead, proximate factors coupled to the precise breeding area proved to be of prime importance in determining defence level, thereby falsifying the idea of a rigidly preprogrammed change of response level based on population parameter means. Instead, parents might gauge their defence to quality of young, as also allowed for in the model, or they may sometimes be constrained to display the full defence.As a by‐product, the experiments permit us to narrow down the range of selective agents producing the male parent's stronger defence. The sex difference, being prevalent in 1st broods and abating in 2nd broods, indicates that the male, by its defence behaviour, not only invests in its offspring but also in its home range and/or its mate. The latter interpretation is supported most directly by the male's defence behaviour in

ISSN:0044-3573    

DOI:10.1111/j.1439-0310.1984.tb01359.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract and SummaryThe functional significance of the wide variation between bird species in the sizes of individual song repertoires is not understood. We have studied the effects of song repertoires on females. Song triggers copulation solicitation display in female sparrows treated with estradiol. Song sparrow males (Melospiza melodia) have repertoires of about 10 song types, and female song sparrows display significantly more to presentations of large repertoires than to a single song type. By contrast, male field sparrows (Spizella pusilla) and white‐throated sparrows (Zonotrichia albicollis) each have only one song type, and their females show no significant increment in responsiveness to repertoires of several song types over a single song type. Swamp sparrows (Melospiza georgiana) fall in between, with male repertoires of three song types. Female swamp sparrows behave in intermediate fashion, responding more to several song types than to one, but the response increment is less than in song sparrows. Thus species differences that males exhibit in song repertoires are paralleled by differences in female responsiveness to multiple song types, implicating variations in female reactivity in the evolution of song repertoires. Female song sparrows respond preferentially to repertoires programmed in eventual variety rather than immediate variety, while field sparrows and white‐throated sparrows show no discriminat

ISSN:0044-3573    

DOI:10.1111/j.1439-0310.1984.tb01360.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract and SummaryThe simultaneously hermaphroditic fish,Hypoplectrus nigricans, engages in a form of reciprocal spawning called “egg trading”, where one partner gives up eggs for fertilization in exchange for the opportunity to fertilize those of the partner. Since egg trading appears to be important in the evolutionary maintenance of hermaphroditism inH. nigricans, an attempt was made to determine if another species,Serranus tortugarum, behaved in a similar fashion.S. tortugarumdo trade eggs, and the phenomenon seems to be widespread in simultaneously hermaphroditic serranids. However, the cues for spawning are much subtler than inH. nigricansand other simultaneously hermaphroditic serranids. This trait appears to be an evolutionary response to the occurrence of heavy sperm competition in the form of streak

ISSN:0044-3573    

DOI:10.1111/j.1439-0310.1984.tb01361.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract and SummaryA three‐year field‐study of Richardson's ground squirrels was conducted to assess whether alarm calling functions to warn close relatives (“kin selection” hypothesis) or manipulate conspecifics (a “selfish” hypothesis).S. richardsoniihad distinct calls for terrestrial and aerial predators, and the responses of squirrels varied appropriately according to the context of calls, implying that calling conveyed correct information concerning the nature of the danger. Alarm calling elicited by naturally occurring encounters with potential predators during 454 h of observation, and by a thrown frisbee in 70 experimental trials, was not equally probable for all age/sex classes. Squirrels were most likely to call when they had offspring or siblings nearby, which is supportive of the hypothesis that alarm calling is maintained by kin selection. Adult males, residing in the vicinity of either their probable progeny or their nonlittermate half‐siblings, were the most likely age/sex class to call during the lactation period when young were below ground and were most vulnerable. I conclude that alarm calling by Richardson's ground squirrels is nepotistic rather than

ISSN:0044-3573    

DOI:10.1111/j.1439-0310.1984.tb01362.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Book reviewed in this article:Motte, I. de la, und D. Burkhardt (1983): Portrait of an Asian stalk‐eyed fly (Portrait einer asiatischen Stielaugenfliege).Burkhardt, D., und I. de la Motte (1983): How stalk‐eyed flies eye stalk‐eyed flies: Observations and measurements of the eyes ofCyrtodiopsis whitei(Diopsidae, Diptera) (Wie Stielaugenfliegen ihresgleichen sehen: Beobachtungen und Messungen an den Augen vonC. w.).Kaiser, W., und J. Steiner‐Kaiser (1983): Neuronal correlates of sleep, wakefulness and arousal in a diurnal insect (Schlaf und Wachsein bei einem tagaktiven Insekt).Tobler, I. (1983): Effect of forced locomotion on the rest‐activity cycle of the cockroach (Einfluß erzwungener Bewegung auf den Ruhe‐Aktivitäts‐Zyklus von Schaben).Tobler, I. (1984): Evolution of the sleep process: a phylogenetic approach (Zur Stammesgeschichte des Schlafverhaltens).Monnier, M., ed. (1980): Biology of sleep. An interdisciplinary survey (Biologie des Schlafes.Jovanovic, U. J., ed. (1973): The nature of sleep (Die Natur des Schlafes.Karacan, J., ed. (1981): Psychophysiological aspects of sleep (Psychophysiologie des Schlafes).Mayes, A., ed. (1983): Sleep mechanisms and functions in humans and animals — an evolutionary perspective (Mechanismen und Funktionen des Schlafs).Aschoff, J., S. Daan, G. A. Groos, eds. (1982): Vertebrate circadian systems: structure and physiology (Struktur und Funktion circadianer Systeme: bei Wirbeltieren).Low, R. (1983): Das Papageienbuch (Parrots — Their care and breeding, übe

ISSN:0044-3573    

DOI:10.1111/j.1439-0310.1984.tb01363.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY