The Spotted Barbtail (Premnoplex brunnescens): male and female parental effort during the nestling period

2015 ◽  
Vol 127 (1) ◽  
pp. 87-91 ◽  
Author(s):  
Jeff Port ◽  
Harold F. Greeney
1997 ◽  
Vol 75 (4) ◽  
pp. 576-581 ◽  
Author(s):  
Lesley J. Evans Ogden ◽  
Bridget J. M. Stutchbury

We followed family groups of Hooded Warblers (Wilsonia citrina) from hatching through to fledgling independence to determine (i) the duration and extent of parental care of fledglings, (ii) the extent of brood division, and (iii) whether male parental effort in caring for nestlings predicts male effort in caring for fledglings. The 9-day nestling period of Hooded Warblers was followed by 4 – 6 weeks of further parental care of fledged young. Parental feeding rates increased from hatching to when the young fledged from the nest, and males fed nestlings significantly more than females did. At the fledgling stage feeding rates to fledglings were significantly higher than at the nestling stage, but there was no difference in feeding rates between the parents. Parents usually divided the brood of fledglings equally, so that each parent assumed full and exclusive care of a subset of the brood. However, many females (45%) initiated a second brood and the male assumed care of the entire first brood at the time when his mate began incubating. The proportion of feeding trips to nestlings made by the male was not predictive of his subsequent effort in the care of fledglings. Exclusion of the fledgling care period in studies of parental investment may give a biased picture of overall investment on the part of both male and female parents.


1992 ◽  
Vol 11 (1) ◽  
pp. 63-80 ◽  
Author(s):  
Bobbi S. Low

Broadly defined, political activity normally involves some form of coalition, usually centering upon resource acquisition, and is not restricted to humans. Male and female mammals appear to have evolved to seek and use resources differently—males to get mates (mating effort) and females to raise healthy, successful offspring (parental effort). Because the return curves for these two types of effort differ in shape, several predictions follow about sex differences in political activity. These predictions are tested using the 93 odd-numbered societies of the Standard Cross-Cultural Sample. Results offer insights into current patterns of male and female political activity in Western societies.


The Auk ◽  
1988 ◽  
Vol 105 (3) ◽  
pp. 553-564 ◽  
Author(s):  
Dianne H. Brunton

Abstract The reproductive investment strategies of the sexes during the breeding season are detailed for Killdeer (Charadrius vociferus), a monogamous plover. I measured the energy investments of the sexes in reproductive, mating, and parental effort. As predicted, males expend more mating effort than females; however, the sexes expend equal amounts of parental effort. Total energy expenditure in reproductive effort (mating and parental effort) during a successful nesting attempt was also equal for the sexes. However, early parental effort expenditures by females, early mating effort expenditures by males, and high rates of nest failure combine to result in female reproductive energy expenditures being significantly higher over the breeding season. This suggests that energy expenditure alone is not adequate for accurate comparisons of the relative investments of the sexes. Studies investigating male and female investments need to consider the degree and pattern of nest failures along with patterns of energy expenditure. The advantages to male and female Killdeer of sharing parental care is demonstrated using adult removal experiments. In general, a deserted parent expends more energy in parental effort than a bi-parental parent and has significantly lower reproductive success. However, males are able to hatch chicks, whereas females lose or abandon their nests within a few days of mate removal. Thus, monogamy in Killdeer appears to result from high nest failure rates, the necessity of two parents for any reproductive success, and the generalizable nature of Killdeer parental care.


The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 205-210 ◽  
Author(s):  
Eduardo T. Mezquida ◽  
Luis Marone

Abstract We present information from 75 nests of Gray-crowned Tyrannulet (Serpophaga griseiceps) found in open Prosopis woodlands of the central Monte desert between 1995 and 1997 and compare it with information corresponding to other species of the genus. Breeding occurred from October to January. Nests are small open cups. Both parents participated in nest building, which lasted 4–7 days. In the Prosopis woodland, 98% of the nests were built in chañar (Geoffroea decorticans), which also is commonly used as a nest plant by S. subcristata in east-central Argentina. Mean clutch size did not vary among years nor within the breeding season, and it was similar to that observed in other Serpophaga. Both male and female shared the 13–15 day incubation period. Hatching was asynchronous. Nestling period lasted 13–14 days, during which both parents reared the chicks. Nesting success (26%) appeared to be less than that previously reported for Nearctic open-nesters (50–60%), and Neotropical open-nesters in dry (50%) and wet tropics (35%). Egg and nestling predation were the main cause of nest failure.


Behaviour ◽  
2019 ◽  
Vol 156 (1) ◽  
pp. 79-107 ◽  
Author(s):  
Carlos de la Cruz ◽  
Mónica Expósito-Granados ◽  
Juliana Valencia

Abstract In many species of cooperative breeding birds, breeders and helpers participate in the parental care with different food provision rules. Normally, helpers feed nestlings less frequently and with smaller quantities of food than breeders. But studies analysing the reaction of feeders to nestling demand are scarce and rarely measure the quantity of food that is actually delivered. In this study, we analysed the provisioning effort of breeders and helpers in the Iberian Magpie, Cyanopica cooki, and how this effort varies with brood demand. We did so by measuring the nestling feeding rate and the biomass supply of each individual. In this way, we obtained a more accurate measurement of the investment assumed by each individual belonging to each status. We found that breeding males visited the nest more often than both breeding females and helpers (mean = 2.24; 0.85 and 1.58, respectively). Furthermore, breeding males delivered more biomass in each feeding visit to the nest than those from other statuses. Breeders, both male and female, increased their parental effort (i.e., provisioning rate and biomass) when brood demand was higher (i.e., more siblings and older nestlings), whereas helpers contributed differently to the nest, but depending on the two types of helpers occurring in this species. Differences in the possible benefits obtained by breeders and helpers may explain these different strategies. In addition, male and female breeders (but not helpers) reduce the feeding rate throughout the breeding season. Thus, in the Iberian magpie, breeders and helpers reveal different patterns of investment depending on nestling food demand.


2019 ◽  
Vol 30 (4) ◽  
pp. 1062-1068 ◽  
Author(s):  
Marwa M Kavelaars ◽  
Luc Lens ◽  
Wendt Müller

Abstract In species with biparental care, individuals only have to pay the costs for their own parental investment, whereas the contribution of their partner comes for free. Each parent hence benefits if its partner works harder, creating an evolutionary conflict of interest. How parents resolve this conflict and how they achieve the optimal division of parental tasks often remains elusive. In this study, we investigated whether lesser black-backed gulls (Larus fuscus) divide parental care during incubation equally and whether this correlates with the extent of vocalizations between pair-members during incubation. We then investigated whether pairs showing more evenly distributed incubation behavior had a higher reproductive success. To this end, we recorded incubation behavior and vocalizations for 24-h time periods. Subsequently, we experimentally increased or decreased brood sizes in order to manipulate parental effort, and followed offspring development from hatching till fledging. Although incubation bouts were, on average, slightly longer in females, patterns varied strongly between pairs, ranging from primarily female incubation over equal sex contributions to male-biased incubation. Pairs contributing more equally to incubation vocalized more during nest relief and had a higher reproductive output when brood sizes were experimentally increased. Thus, vocalizations and a more equal division of parental care during incubation may facilitate higher levels of care during the nestling period, as suggested by a greater reproductive success when facing high brood demand, or they indicate pair quality.


1993 ◽  
Vol 71 (2) ◽  
pp. 227-232 ◽  
Author(s):  
Jeffrey G. Kopachena ◽  
J. Bruce Falls

We studied parental care in White-throated Sparrows (Zonotrichia albicollis) during the last 4 days of the nestling period and the first 4 days of the fledgling period. Both parents made more provisioning trips and delivered more food to fledglings than to nestlings. Though male and female parents provided nestlings with equal amounts of food, female parents provided fledglings with more food than did male parents. Fledglings received fewer items per trip than did nestlings. This suggests that fledging was associated with a change in parental foraging strategies. Postfledging parental care did not differ between broods from late nests and broods that were to be followed by a second nesting attempt.


Author(s):  
R. F. Bils ◽  
W. F. Diller ◽  
F. Huth

Phosgene still plays an important role as a toxic substance in the chemical industry. Thiess (1968) recently reported observations on numerous cases of phosgene poisoning. A serious difficulty in the clinical handling of phosgene poisoning cases is a relatively long latent period, up to 12 hours, with no obvious signs of severity. At about 12 hours heavy lung edema appears suddenly, however changes can be seen in routine X-rays taken after only a few hours' exposure (Diller et al., 1969). This study was undertaken to correlate these early changes seen by the roengenologist with morphological alterations in the lungs seen in the'light and electron microscopes.Forty-two adult male and female Beagle dogs were selected for these exposure experiments. Treated animals were exposed to 94.5-107-5 ppm phosgene for 10 min. in a 15 m3 chamber. Roentgenograms were made of the thorax of each animal before and after exposure, up to 24 hrs.


Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs

Gonadotroph cell adenomas of the pituitary are infrequent in human patients and are not invariably associated with altered gonadal function. To date, no animal model of this tumor type exists. Herein, we describe spontaneous gonadotroph cell adenomas in old male and female Sprague-Dawley rats by histology, immunocytology and electron microscopy.The material consisted of the pituitaries of 27 male and 38 female Sprague Dawley rats, all 26 months of age or older, removed at routine autopsy. Sections of formal in-fixed, paraffin-embedded tissue were stained with hematoxylin-phloxine-saffron (HPS), the PAS method and the Gordon-Sweet technique for the demonstration of reticulin fibers. For immunostaining, sections were exposed to anti-rat β-LH, anti-ratβ-TSH, anti-rat PRL, anti-rat GH and anti-rat ACTH 1-39. For electron microscopy, tissue was fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4 and embedded in epoxy-resin. Tissue fixed in 10% formalin, embedded in epoxy resin without osmification, was used for immunoelectron microscopy.


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