Effects of stimuli emanating from the nest on the reproductive cycle in the ring dove. I: Pre-laying behaviour

The course of several behavioural patterns could be influenced by controlling the state of the nest available to a pair of ring doves (Streptopelia risoria). These patterns were: wing-flipping, handling of nesting material, nest bowl occupancy, and nervous activities. In groups having to build nests, the onset of wing-flipping by the female occurred at a predictable time before egg-laying. It is argued that during nest-building a female influences the male to carry material to her by sitting in the nest bowl and wing-flipping. In pairs provided with a completed nest, the course of the pre-laying cycle was changed and the ‘typical’ sex roles did not emerge. The relationships between the male and female are discussed.     

Effects of stimuli emanating from the nest on the reproductive cycle in the ring dove. III: building in the postlaying period and effects on the success of the cycle.

Nest-building as a functional activity is shown to continue well into the incubation period of the ring dove (Streptopelia risoria), its intensity depending on the state of the nest. The presence of a nest has profound consequences on breeding success: pairs with no nests did not incubate well and did not hatch their eggs. Pre-laying disruption of the nest or of the usual roles of the male and female had no effect on incubation as long as a nest was present when the eggs were laid. It is concluded that the presence of a nest is necessary for the proper establishment of incubation. The possible role of the nest in incubation is discussed.     

Plasma luteinizing hormone during the breeding cycle of the female ring dove

Plasma luteinizing hormone (LH) levels in serial blood samples of female ring doves (Streptopelia risoria) were measured by radioimmunoassay method. Our findings indicate the following pattern of LH levels: LH increases during early courtship which reaches a peak (5.43 ± 0.79 ng/ml) during the nesting period. LH declines following egg-laying (3.77 ± 0.33 ng/ml) and again after hatching (2.23 ± 0.28 ng/ml). It remains high in females which laid infertile eggs initially and subsequently showed a further laying. The results are compared with published data on plasma estrogens and progesterone in the dove's breeding cycle.     

Effects of nest-box density on the behavior of Tree Swallows during nest building

ABSTRACT.   In territorial species, increased density is often linked to an increase in aggressive interactions, which may result in trade-offs between competitive behavior and nest construction. We examined the impact of nesting in areas of high-density versus low-density nest boxes on conspecific interactions and nest-building effort in a population of Tree Swallows ( Tachycineta bicolor ). We also examined whether expected differences in behavior related to variation in nest quality and reproductive success in high-density and low-density areas. No differences in either nest-building behavior or reproductive success were observed between areas of high-density and low-density boxes, but there was a tendency of more frequent behavioral interactions at high density. Similarly, there was a significant difference between pairs defending single nest boxes and those defending multiple nest boxes in the number of interactions with conspecifics. These results suggest that although there may be more competition with conspecifics for Tree Swallows nesting at high density, this does not appear to affect either nest quality or reproductive success.     

Changes in aromatase activity in the brain of the male ring dove (Streptopelia risoria) during the breeding cycle

Aromatase activity was measured in striatal and hypothalamic regions of the brain of the male ring dove throughout its breeding cycle. The enzyme activity in the anterior hypothalamus and hyperstriatum was significantly reduced in broody birds. A reduction in plasma LH and the number of spermatogonia per tubule cross-section were also observed at this time. The results support the view that testosterone is involved in the control of aromatase activity in the anterior hypothalamus and hyperstriatum. The enzyme activity in the posterior hypothalamus, paleostriatum and archistriatum showed no changes throughout the breeding cycle, indicating that other factors in addition to testosterone are involved in controlling the enzyme in these tissues.     

Effects of furazolidone on some reproductive hormones during oestrous cycle in the goat

In non-pregnant goat luteolysis is characterized by a decline in peripheral plasma progesterone level and increased peripheral plasma concentrations of testosterone (T) and 5 alpha-dihydrotestosterone (DHT). Daily oral doses of furazolidone (80 mg/kg) between days 10 and 16 delayed luteolysis and suppressed both the decline in progesterone concentrations and the increase in T and DHT level.     

Diagnostic irradiation of women during the reproductive period.

The date of onset of the last menstrual period should be given on radiographic requisitions for all women of reproductive age. Every effort should be made to avoid unnecessary irradiation of any woman who might be pregnant. Radiation damage in the first 2 weeks of pregnancy, however, should be "all or none", resulting in either a miscarriage or a normal child. Diagnostic radiology procedures are not indications for therapeutic abortion. Ultrasound has now replaced ionizing radiation in most examinations of the fetus and placenta. Pelvimetry should be done only when the decision to do a cesarean section hinges on precise knowledge of measurements of the bony pelvis. On the rare occasion when a radiograph of the fetus is necessary the woman should be prone for the examination. All such examinations are best ordered after consultation with a radiologist. Radiography of distant areas with the beam directed away from the woman''s abdomen can be done without concern at any stage of pregnancy.     

Changes in the immune response of the ring dove (Streptopelia risoria) during incubation

Changes in immune parameters following antigen administration were evaluated in non-breeding and incubating, male and female ring doves. The time course in the changes in immune parameters in response to antigen agrees closely with earlier studies on the domestic fowl. Incubating doves possessed phagocytes with increased activity, although there was no increase in cell number. These results suggest that in the incubating bird, with high levels of plasma prolactin, there is an antigen-independent increase in immune cell activity but no antigen-dependent action on cell number. The biological significance of the changes in the immune system during incubation awaits further study.     

Artificial nest box use by the North Island saddleback: Effects of nest box design and mite infestations on nest site selection and reproductive success

Abstract

The pests and weeds that can affect conservation values in New Zealand are mostly introduced species, including 31 species of mammals, a small number of birds, a few fish and amphibians, an unknown number of invertebrate species (but particularly two wasps), and at least 75 introduced plants capable of permanently altering native ecosystems.     

Effects of preoptic and hypothalamic lesions in female turkeys during a photoinduced reproductive cycle

Prolactin (Prl) is released by electrical stimulation in the turkey hypothalamus and preoptic area (POA). Possible trajectories for POA efferents to the median eminence (ME) were tested by placing lesions in the POA, the lateral hypothalamus (LHy), or the ventromedial nucleus of the hypothalamus (VMN) of reproductively quiescent turkey hens, then subjecting them to long photoperiods while monitoring their blood Prl levels and nesting activities. In addition, lesions were made in the VMN of a group of incubating hens to learn whether the lesions would cause the elevated Prl levels to fall or interfere with incubation behavior. Lesions in medial POA, LHy, or VMN prevented the onset of incubation and prevented the large rise in Prl associated with it. However, these lesions did not interfere with the initial, more gradual Prl rise caused by increasing daylengths. Lesions in LHy or VMN appeared to interfere with a pathway lying laterally from POA to ME. Electrical stimulation in medial POA, which caused an increase in circulating Prl, failed to do so in hens with LHy or VMN lesions. Lesions in the VMN of incubating hens caused them to leave the nest and suffer a large decline in Prl, both within 48 h. It is tentatively suggested that incubation behavior and its associated elevated Prl are prevented by the POA lesions and that lesions in LHy or VMN, which mimic POA lesion effects, interfere with POA efferents projecting to ME.     

The transition from sitting on eggs to sitting on young in ring doves, Streptopelia risoria: squab-egg preferences during the normal cycle.

Ring doves of both sexes sit on young squabs after hatching in much the same manner as they sit on eggs before hatching, but this study demonstrates that the preferred stimulus varies with the state of the animal. A simultaneous, squab-egg choice test was given on days 1, 4, 10, and 13 of incubation and on the day following hatching in normal reproductive cycles of experienced and naïve male and female ring doves. Naïve doves were more likely than experienced doves to choose eggs throughout the cycle (P<0·005) and, overall, eggs were more likely to be chosen during early incubation and squabs posthatching (P<0·005).     

Temperament and ovarian reproductive hormones in women: evidence from a study during the entire menstrual cycle

Personality and temperament were hypothesized to function as important factors affecting life history strategies. Recent research has demonstrated the association between temperamental traits and reproduction in humans, however, the underlying mechanisms are still poorly understood. This study presents evidence for an association between temperamental traits and woman's fecundity, as indicated by levels of ovarian steroid hormones during the menstrual cycle. On a large sample of urban, reproductive age women (n = 108) we demonstrated that activity, endurance and emotional reactivity are associated with levels of estrogen and with a pattern of change of progesterone levels. Women high in activity, high in endurance and low in emotional reactivity had up to twice as high estradiol levels and more favorable progesterone profiles as women low in activity, low in endurance and high in emotional reactivity. The temperamental traits we measured highly overlap with extraversion, neuroticism and negative emotionality that were reported to correlate with reproductive success. Our findings thus suggest a possible explanation for these relationships, linking personality and women's reproductive success through a hormonal pathway.     

Alteration of glutathione reductase expression in the female reproductive organs during the estrous cycle.

The enzyme glutathione reductase (GR) recycles oxidized glutathione (GSSG) by converting it to the reduced form (GSH) in an NADPH-dependent manner. A specific antibody raised against recombinant rat GR was used to localize the protein in the female reproductive organs during the estrous cycle in the rat. In the ovary, the strongest reactivity to the antibody was observed in oocytes, followed by granulosa cells, corpus luteum, and interstitial cells. A strongly positive reaction was also observed mainly in the oviduct epithelia, uterine epithelia, and endometrial gland in the reproductive tract. Oviducts contained the highest GR activity. The GR activity of uterus during metestrus was about twice as high as that for other stages of the cycle. The levels of GR proteins in the tissues roughly matched the activities. The expression of the GR mRNA was highest during metestrus. Because GSH is known to increase gamete viability and the efficiency of fertility, GR, which is expressed in these tissues, is predicted to play a pivotal role in the reproduction process as a source of GSH.