NESTING OF THE PURPLE-THROATED CARIB HUMMINGBIRD

We present data on certain parts of the nesting biology of the Purple-throated Carib Humming- bird Eulampis jugularis on the island of Dominica, British West Indies. We watched two nests with eggs and young and a single nest under construction. Incubation was in short periods averaging about six minutes. Females at both nests with eggs continued adding material to the nest until the end of incubation. We suggest that this common practice among hummingbirds may insure that a limited amount of energy at the time of initial nest-building and egg-production is optimally apportioned between the two activities. Brooding ceased in one nest when the young were about 13 days old. Feeding rates stayed relatively constant at one to two per hour throughout the nearly complete nestling period in one nest. Average time per feeding declined, apparently as the female-young interaction became more efficient with maturation of the young. Nesting females foraged on both insects and nectar. We could not be sure what they were feeding the young. Defence of the nest varied with the position of the female and the type of intruder. The aggressive behaviour associated with defence varied according to the size and type of intruder. We concluded that for the one nest of Eulampis for which we had the most complete data, had there been three young, the female would have been unable to provide sufficient food to nourish them. However, the universal clutch size of two and nearly universal promiscuity in humming- birds is strong evidence that factors other than the ability of adults to feed more than two young are important in determining clutch size.     

Die Nachwirkung von Produkten resistenter interspezifischer Reben-Arthybriden in unbehandelten Nachzuchtgenerationen (dargestellt in Versuchen mit Hühnern)

Zusammenfassung (Zum besseren Verständnis der zitierten genealogischen Zusammenhänge wird auf Tab. 1 S. 353 (Material und Methodik) verwiesen.)Durch eine 6–8 Wochen anhaltende Verfütterung der Produkte — Weine wie (alkoholfreie) Säfte — von relativ resistenten Reben-Arthybriden, die aus Kreuzungen sensitiver Vitis vinifera-Varietäten mit ± resistenten amerikanischen Wildreben (F₁, F₂R) hervorgegangen waren, ließ sich bei Hühnern eine Prägung auslösen, die bei ihren unbehandelten F₁-Nachkommen in über 40% der Fälle zu Mißbildungen hauptsächlich der Ständer und des Gefieders führte. Diese Effekte hatten sich mehrfach reproduzieren lassen.Normal gehaltene F₁-Geschwister behandelter Eltern, miteinander verpaart, ergaben in der F₂ wiederum, einen gewissen Prozentsatz (8–11%) der gleichen Aberrationen an Ständern und Gefieder wie bei der F₁. Dabei spielte es keine Rolle, ob Normale, Anomale oder Krüppel miteinander gekreuzt worden waren.Wurden F₂-Geschwister miteinander verpaart, so reduzierte sich der Effekt in der F₃ auf 0,9–2,2% an Mißbildungen. Dem zahlenmäßigen Rückgang der Häufigkeit von Aberranten entsprach ebenso ein allgemein verminderter Grad der betreffenden Schädigung.Normale aus der F₃ brachten mit normalen Individuen ihrer Elterngeneration verpaart (F₃ × F₂) keine mißbildeten Nachkommen hervor, während bei der reziproken Kreuzung (F₂- × F₃-) aus den Eiern dieser anomalen F₂- noch 4,7% der Tiere mit mißbildeten Ständern und 21,9% mit defekten Federn schlüpften.In der F₅, hervorgegangen aus miteinander verpaarten Normalen der F₄R, traten weitere 4,6% an Beinmißbildungen und 6,9% an Feder-Anomalien auf.Dagegen fanden sich keine Anomalien mehr, wenn Standard- mit einem aberranten F₄- verpaart worden waren. In den Kontrollen traten keine Mißbildungen auf.Die einmal in der p₁ durch die Versuchstränken gesetzte Prägung erwies sich in 5 Generationen zwar sowohl nach der Zahl der in der Folge entstandenen Anomalien als auch hinsichtlich des Schweregrades ihrer Ausprägung als regressiv, ohne daß in diesem Zeitraum jedoch ein völliges Abklingen des Einflusses bei allen Tieren zu verzeichnen gewesen wäre.Es wird vermutet, daß die Effekte vorwiegend aufgrund latent vorhandener Veränderungen im weiblichen Keimplasma ausgelöst werden, die — möglicherweise durch Umweltfaktoren begünstigt — die Entwicklung der Embryonen individuell beeinflussen.Die Wirkungen im Erscheinungsbild gleichen etwa den durch Vitamin B₂-Mangel hervorgerufenen Anomalien, so daß möglicherweise auch in unserem Fall etwa eine stoffliche Blockierung im Vitaminhaushalt der Embryonen als Ursache der beobachteten Mißbildungen nicht auszuschließen ist. Die weitgehende Normalisierung der Feder-Defekte anläßlich der ersten echten Mauser, zeitlich mit der beendeten Resorption des (mütterlich geprägten) Dotters im Küken und mit der Autonomisierung des Vitaminhaushaltes im Jungtier einhergehend, deutet in diese Richtung. Eine Rehabilitierung der Beinmißbildungen ließ sich in keinem Fall feststellen.Die zweimalige Behandlung derselben Hühner und Hähne in zwei aufeinanderfolgenden Jahren scheint sich im Effekt nicht additativ auszuwirken. Vielmehr gestattet offenbar die zwischenzeitlich normale Haltung, durch den relativ hohen physiologischen Umsatz besonders bei den weiblichen Tieren (Eiproduktion, Mauser) begünstigt, eine weitgehende Normalisierung des Keimplasmas.

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After-effects in untreated progenies from chickens treated with the products from resistant interspecific grape-vine hybrids

Summary Feeding hens and cocks for 6–8 weeks with the products — wines and juices — from ± resistant interspecific grapevine varieties (F₁, F₂R), i.e. from crosses between sensitive types of Vitis vinifera and ± resistant American wild types, led to physiological changes of the treated animals. These changes became evident by more than 40% of malformations, especially of legs and plumage, among the individuals of their untreated F₁ progeny. These effects proved to be reproducable.Among the F₂-individuals from crosses between untreated F₁ brothers and sisters 8–11 % of the chickens again carried anomalies of the same kind as found in F₁. No relation could be observed between the number of F₂ malformations and the types of F₁-parents: both of them had been either normal, slightly anomalous or crippled.In the following generation (F₃) from F₂ brothers and sisters, again selected for equal types (normals, slightly anomalous or crippled ones) and crossed among themselves or to standard-, the number of malformations became reduced to 0,9–2,2%. From this generation on severely crippled types were almost lacking and only slightly anomalous ones showed up, characterized by crippled toes and/or plumage defects.The following crosses between F₃ and F₂ did not give rise to anomalies among the progeny of the next generation, as was the case when normal (F₂ 1966) were crossed to standard-, while from the reciprocal combination (F₂ × F₃) again 4,7% of the F₄R chickens hatched with moderately or slightly deformed feet besides 21,9% of individuals with defective feathers.Among the chickens of the following generation (F₅) from crosses between normal F₄R brothers and sisters there resulted another 4,6% and 6,9% of individuals with crippled toes (slight type) and defective wing feathers, respectively. On the other hand only normal chickens hatched from the eggs of standard- crossed to an anomalous from F₄R. The controls were free from anomalies.Thus the effects of experimental beverages fed once to the P₁, had caused in the following generations (F₁– F₅) certain numbers of individuals with malformations, developing in declining numbers and with gradually reduced severity. The 5 generations observed did not suffice for a complete rehabilitation.It is suggested that the effects were caused by latent though increasingly reduced changes within the female germ plasm, coming about by some unknown substance(s) immanent to the relatively resistant grape-vine cultivars used. Individually acting upon the embryological development, environmental influences are supposed to add to the effects.Since the types of malformations of legs and plumage can easily be compared to those observed in cases of vitamin B₂-deficiency in the diet of chicks, the substance(s) applied with the beverages possibly reduce(s) the embryonic exploitation rate of vitamins, too. Another hint in that direction could be the more or less complete normalization of the plumage defects at the time of the first moulting, i.e. when the maternal egg yolk probably has become fully absorbed by the growing chicken and the exploitation of vitamins has turned autonomous. Rehabilitation of crippled legs never has been found.Treating the same animals in two successive years, with some months of water-feeding in between, does not seem to give an additive effect as to the number of anomalies developing in both F₁-generations. During the interval of normal feeding the relatively high turnover, especially in hens, by the building up of eggs and by moulting, apparently causes a general normalization within the germ plasm before the second treatment.Nothing is known about the type of substance (s) fed with the products from resistant grape-vines, nor do we know anything about the pattern of their action and reaction, leading to changes within the germ plasm and finally reducing the utilization of vitamins in chick embryos from individuals once treated in some former generation.

     

Persistence of maternal isoenzyme patterns of the lactate dehydrogenase and phosphoglucomutase system during early development of hybrid trout

Developmental changes in the isoenzyme patterns of LDH and PGM during early embryogenesis (until hatching) in two trout species (Salmo trutta and Salmo irideus) as well as in their reciprocal interspecific hybrids are reported, completing a previous study which had commenced from hatching onward (Hitzeroth et al., 1968). Isoenzymes of both systems occur in unfertilized eggs and in embryos from fertilization onward. Until about the Augenpunkt stage, the isoenzyme patterns remain unchanged and are identical to the patterns of unfertilized eggs; the reciprocal hybrids correspond to the respective maternal species. Additional isoenzymes appearing for the first time at about the Augenpunkt stage in the interspecific hybrids show the same electrophoretic mobility as those in the animals of the respective maternal species at this developmental stage. It is discussed whether the appearance of additional isoenzymes characterizes the activation of maternally derived alleles of the embryonic genome, or whether maternally derived cytoplasmic factors are responsible for the occurrence of these additional bands.Supported by the Deutsche Forschungsgemeinschaft.     

Interspecific hybridization betweenDaphnia hyalina,D. galeata,andD. cucullata and seasonal abundances of these species and their hybrids

The three cladoceran speciesDaphnia hyalina, D. galeata, andD. cucullata frequently coexist in the lakes of northern Germany. Although there are some problems in distinguishing them morphologically, they are easily determined by gelelectrophoresis: each species carries a different allele at the glutamate oxaloacetate transaminase (GOT) locus. Animals morphologically intermediate between two species are heterozygous for the alleles carried by the species they resemble. This pattern is in agreement with the findings at other loci, where also diagnostic alleles exist. These findings are most easily explained by interspecific hybridization between the three species. No evidence is found for backcrosses involving hybrids ofD. cucullata, whereas some backcrosses betweenD. hyalina, D. galeata, and their hybrids are found in some lakes. In four lakes the seasonal abundances of the three species and their hybrids are determined.     

Changes in sperm plasma membrane lipid diffusibility after hyperactivation during in vitro capacitation in the mouse

We have used the technique of fluorescence recovery after photobleaching to measure the diffusibility of the fluorescent lipid analogue, 1,1'-dihexadecyl 3,3,3',3'-tetramethylindocarbocyanine perchlorate on the morphologically distinct regions of the plasma membranes of mouse spermatozoa, and the changes in lipid diffusibility that result from in vitro hyperactivation and capacitation with bovine serum albumin. We found that, as previously observed on ram spermatozoa, lipid analogue diffusibility is regionalized on mouse spermatozoa, being fastest on the flagellum. The bovine serum albumin induced changes in diffusibility that occur with hyperactivation are also regionalized. Specifically, if we compare serum incubated in control medium, which maintains normal motility, with those hyperactivated in capacitating medium, we observe with hyperactivation an increase in lipid analogue diffusion rate in the anterior region of the head, the midpiece, and tail, and a decrease in diffusing fraction in the anterior region of the head.     

Rules of evidence in psychophysiological investigations

Conventional rules encourage an investigator to focus primarily on quantifiable data. In psychophysiological studies, however, the most relevant data may be nonquantifiable, at least at the present time. Behavior, visceral or general, does not necessarily depend on the quantity of a particular stress, but rather is the result of a complex interactive central processing of afferent signals, reflecting more the relevance of actuating factors than their quantitative features. Thus, the rules of evidence must ask not only for measurement, when possible, but for context as well and for data on related intangibles that determine the significance of an experience to an affected individual. Such an inquiry requires the perspicacity of a skilled and disciplined observer. As the practiced ear of a well-trained cardiologist can draw reliable anatomical inferences from listening to the heartbeat, so the eyes and ears of an educated physician should be able to determine the significance of events to his patient with a fair degree of reliability. Both the physician and the cardiologist, however, must deal with the potential distortion brought on by their own biases. Despite problems of bias, lack of replicability, and the need to persist in efforts toward precise measurement, progress continues in understanding the contribution of psychosocial stresses to a variety of gastrointestinal, cardiovascular, respiratory, cutaneous, and other bodily disturbances and the pathways and neurohumoral mechanisms whereby they are mediated. The agenda now calls for developing new strategies for dealing with the powerful intangibles that activate the mechanisms. Meanwhile, as Robert Morrison once cautioned, "We must not expect a science to know more than it does."