scholarly journals MITE (ACARINA) POPULATIONS IN RING-BILLED GULL NESTS

1974 ◽  
Vol 106 (3) ◽  
pp. 319-327 ◽  
Author(s):  
R. Freitag ◽  
J. P. Ryder ◽  
P. Wanson
Keyword(s):  
Lake Superior ◽  
Egg Laying ◽  
Mite Population ◽  
Breeding Cycle ◽  
Nest Density ◽  
Population Densities ◽  
Egg Hatching ◽  
Northwestern Ontario ◽  
Larus Delawarensis ◽  
Nest Initiation

AbstractMites collected from 69 Larus delawarensis Ord nests on Granite Island, Lake Superior, northwestern Ontario, during the summers of 1972 and 1973 showed phenological relationships with the breeding cycle of the gulls. The populations of five selected mite genera varied in relation to nest initiation, egg laying, and egg hatching periods of the gulls. Moisture within the nests significantly affected mite population densities, whereas nest density did not.

An assessment of possible intraspecific brood parasitism in ring-billed gulls

1984 ◽  
Vol 62 (9) ◽  
pp. 1680-1684 ◽  
Author(s):  
Peter M. Fetterolf ◽  
Hans Blokpoel
Keyword(s):  
Brood Parasitism ◽  
Egg Laying ◽  
Present Evidence ◽  
Intraspecific Brood Parasitism ◽  
Egg Shape ◽  
Larus Delawarensis ◽  
Egg Colour ◽  
Lower Fertility ◽  
Nest Initiation

Ring-billed gull (Larus delawarensis) egg colour, egg dimensions, egg shape, egg-laying intervals, nest initiation dates, and fertility were documented at several different colonies over a 6-year period. Significantly greater variability in egg dimensions and egg shape, lower fertility, and atypical laying intervals in mixed-coloured clutches compared with even-coloured clutches suggest that more than one female laid eggs in mixed-coloured clutches. We present evidence that some odd-coloured eggs were laid by females that parasitized nests.

Female-Female Pairing in Ring-Billed Gulls

The Auk ◽  
1979 ◽  
Vol 96 (1) ◽  
pp. 1-5 ◽  
Author(s):  
John P. Ryder ◽  
Patricia Lynn Somppi
Keyword(s):  
Growth And Development ◽  
Hatching Success ◽  
Lake Superior ◽  
Adaptive Significance ◽  
Egg Laying ◽  
Egg Dumping ◽  
Larus Delawarensis

Abstract Female-female pairs of Ring-billed Gulls (Larus delawarensis) were recorded attending supernormal clutches (5-8 eggs) on Granite Island, northern Lake Superior in 1978. Female-female pairs complete their clutches usually before the peak of egg-laying in the colony. Supernormal clutches completed after the peak are thought to result from egg-dumping by several unpaired females. Compared to normal 3-egg clutches, laid early in the season, the average hatching success of supernormal clutches was lower (8-20% vs 80-90%) and over 50% of the embryos showed depressed growth and development. Although the phenomenon of homosexual pairing is likely not recent in Ring-billed Gulls, as compared to the situation in Western Gulls, the adaptive significance of such pairs is currently unknown.

Reproductive Performance of Female-female Pairs and Polygynous Trios of Ring-Billed Gulls

The Auk ◽  
1983 ◽  
Vol 100 (3) ◽  
pp. 658-669 ◽  
Author(s):  
Kit M. Kovacs ◽  
John P. Ryder
Keyword(s):  
Reproductive Success ◽  
Reproductive Performance ◽  
Similar Pattern ◽  
Hatching Success ◽  
Lake Superior ◽  
Nest Density ◽  
Nearest Neighbour ◽  
Neighbour Distance ◽  
Larus Delawarensis ◽  
Breeding Seasons

Abstract We studied female-female pairs of Ring-billed Gulls (Larus delawarensis) on Granite Island, northern Lake Superior, during the breeding seasons of 1979 and 1980. In 1979 the colony consisted of approximately 2,400 nesting pairs, with a total of 99 nests containing 5-7 eggs (superclutches). In 1980 the colony had increased in size to 2,600 nests and contained a total of 71 superclutches. We discuss the difficulty of distinguishing nests in which superclutches have been laid by female-female pairs from single-cup nests used by polygynous groups or from nests receiving dump eggs. Nests containing superclutches were larger than those containing normal-sized clutches. They were not differentially located by substrate, nest density, or location within the colony. Nearest-neighbour distance was also similar for the two clutch types. Eggs laid in superclutches were slightly smaller than those from normal-sized clutches (1-4 eggs) but did not differ in shape. Significantly more eggs from superclutches rolled from the nest or were destroyed or abandoned than from normal-sized clutches. The proportion of nests that hatched at least one chick did not differ significantly between the two clutch types. Hatching success for superclutches was 34% in 1979 and 30% in 1980, whereas for normal-sized clutches it was 77% in 1979 and 61% in 1980. Chicks from superclutches had a higher rate of mortality during the week following hatching than did chicks from normal-sized clutches. Chicks from the former hatched at significantly lighter weights than did those from the latter during both years of study, but their weights did not differ after the first week posthatch. Tarsal and culmen measurements followed a similar pattern to that of weight. Chicks from normal-sized clutches had a significantly higher fledging success than did those from superclutches. The reproductive success of four polygynous groups is also reported.

Variation during breeding in parameters that influence blood oxygen carrying capacity in shearwaters

2000 ◽  
Vol 48 (4) ◽  
pp. 347 ◽  
Author(s):  
Cristina Davey ◽  
Alan Lill ◽  
John Baldwin
Keyword(s):  
Carrying Capacity ◽  
Energy Demand ◽  
Blood Parameters ◽  
Aerobic Metabolism ◽  
Egg Laying ◽  
Main Trend ◽  
Breeding Cycle ◽  
Blood Oxygen ◽  
Pattern Of Variation ◽  
Oxygen Carrying Capacity

Parameters that influence blood oxygen carrying capacity (whole-blood haemoglobin content, haematocrit and red blood cell count) were measured in samples of 30 breeding, adult short-tailed shearwaters (Puffinus tenuirostris) on Phillip Island, Victoria at seven key stages of their reproductive cycle. The aim of the investigation was to determine whether variation in blood oxygen carrying capacity during the birds’ 7-month breeding cycle was correlated with variation in the energy demands they experienced or was an incidental by-product of other physiological changes. All the blood parameters varied significantly during breeding, but the pattern of variation was only partly correlated with the likely pattern of changing energy demand imposed on parents by their schedule of breeding activities. The main trend conceivably related to energy demand was that significantly higher values were recorded for these blood parameters during the nestling stage than earlier in the breeding cycle. This could have reflected the high costs of the very long foraging trips undertaken by parents feeding nestlings, but it could also have occurred in preparation for the long migration undertaken soon after breeding finished. It involved an ~10% increase in blood oxygen carrying capacity above the lowest mean value recorded during the breeding cycle and so other mechanisms must also be employed to achieve the increase in aerobic metabolism likely to be required at this stage. The lack of adjustment of blood oxygen carrying capacity to energy demand early in the breeding cycle suggests that either oxygen delivery was not a rate-limiting process for aerobic metabolism at that time or that delivery was enhanced through other mechanisms. At egg laying, females had a lower haematocrit and erythrocyte count than males, which could be attributable to either estrogenic suppression of erythropoiesis or an increase in osmotic pressure of the blood associated with yolk synthesis. Immature, non-breeding birds attending the colony were of similar mass to adults, but did not show the increase in the parameters determining blood oxygen carrying capacity that occurred in adults later in the breeding cycle. Factors other than changing energy requirements (dehydration, burrow hypoxia and differential responsiveness to capture stress) that might have influenced the pattern of variation in blood oxygen carrying capacity of adults during breeding are discussed.

scholarly journals Sources of Variation in Survival of Breeding Female Wood Ducks

The Condor ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 201-210 ◽  
Author(s):  
Kevin M. Hartke ◽  
James B. Grand ◽  
Gary R. Hepp ◽  
Travis H. Folk
Keyword(s):  
Body Condition ◽  
Weight Of Evidence ◽  
Breeding Cycle ◽  
Breeding Period ◽  
Information Theoretic ◽  
Wood Ducks ◽  
Daily Survival ◽  
Radio Transmitters ◽  
Sources Of Variation ◽  
Nest Initiation

Abstract In waterfowl, reproduction is physiologically demanding and females are exposed to varying risks of mortality at different periods of the breeding cycle. Moreover, differences among females may influence survival within breeding periods. We captured and fitted female Wood Ducks (Aix sponsa) with radio-transmitters before nest initiation during two breeding seasons to estimate survival and investigate sources of variation in survival. We partitioned the breeding season into three periods (preincubation, incubation, postnesting) according to breeding status of individual females, and used information-theoretic methods to compare models in which daily survival varied among periods, between successful and failed nesting females, and with parameters describing individual heterogeneity. Our analysis suggested that daily survival was best modeled as a function of breeding period, differences between successful and failed nesting females during postnesting, and early incubation body condition of successful females during postnesting. Model-averaged daily survival was 0.9988 (95% CL: 0.9963–0.9996) during preincubation and 1.0 during incubation. Postnesting daily survival was 1.0 for failed nesting females and 0.9948 (0.9773–0.9988) for successful females, suggesting a trade-off between current reproduction and survival. Female age, body condition at capture, nest initiation date, and brood size generally were not useful for explaining variation in survival. Only early incubation body condition was important for modeling survival of successful females during postnesting; however, weight of evidence was limited and the effect on survival was weak. Mortality was greatest for females during preincubation and for females that nested successfully. Results support the hypothesis that brood care is costly for females.

Breeding Cycle and Behavior of the Semipalmated Sandpiper at Barrow, Alaska

The Auk ◽  
1979 ◽  
Vol 96 (1) ◽  
pp. 56-67 ◽  
Author(s):  
Shoshana Ashkenazie ◽  
Uriel N. Safriel
Keyword(s):  
Home Range ◽  
Pair Formation ◽  
Egg Laying ◽  
Breeding Cycle ◽  
Male And Female ◽  
Semipalmated Sandpiper ◽  
The Family ◽  
Polygonal Area ◽  
Calidris Pusilla ◽  
And Behavior

Abstract Pair formation of Calidris pusilla near Barrow, Alaska occurs 3-6 days after the territory is established. The pair is then engaged in nest scraping displays during 2-3 days, in which 10-12 scrapes are made by the male and examined by the female. Eventually 2-3 scrapes are lined by the female, and in one of these the first egg is laid 4-6 days after pairing. During the egg-laying period further lining is performed by the female and partial incubation takes place by both sexes. Continuous incubation commences 8 h prior to laying of the 4th egg. Male and female alternate in incubation: in the first 2 days a turn lasts 3-5 h, and the duration gradually increases up to 13-14 h during the 2nd week. Long incubation turns reduce the number of approaches to the nest and may therefore reduce the chances of it being discovered by predators. The incubating bird is intermittently engaged in egg-rolling and in camouflaging the nest by bending adjacent grass blades over its back, and is constantly alert. The off-duty bird may feed 2-3 km away from the nest. The eggs hatch after 20 days of incubation, all within 1 day. Females desert the family 2-8 days after hatching: they desert late if hatching is early, and early if hatching is late in the season. After female departure the family moves from the nesting territory, typically in a high-centered polygonal area, to establish a home range as far as 2-3 km away, often in a low-centered polygonal area. During the first 6-8 days after hatching, the male prepares each evening a scrape for night brooding. After fledging, the male and young join wandering flocks.

Latrophilin mediates insecticides susceptibility and fecundity through two carboxylesterases, esterase4 and esterase6, in Tribolium castaneum

2019 ◽  
Vol 109 (4) ◽  
pp. 534-543 ◽  
Author(s):  
L. Wei ◽  
S. Gao ◽  
W. Xiong ◽  
J. Liu ◽  
J. Mao ◽  
...  
Keyword(s):  
Tribolium Castaneum ◽  
Molecular Mechanisms ◽  
Vital Role ◽  
Egg Laying ◽  
Egg Hatching ◽  
Compensatory Response ◽  
Physiological Processes ◽  
Similar Phenotype ◽  
G Protein Coupled ◽  
Insight Into

AbstractLatrophilin (LPH) is known as an adhesion G-protein-coupled receptor which involved in multiple physiological processes in organisms. Previous studies showed that lph not only involved the susceptibility to anticholinesterase insecticides but also affected fecundity in Tribolium castaneum. However, its regulatory mechanisms in these biological processes are still not clear. Here, we identified two potential downstream carboxylesterase (cce) genes of Tclph, esterase4 and esterase6, and further characterized their interactions with Tclph. After treatment of T. castaneum larvae with carbofuran or dichlorvos insecticides, the transcript levels of Tcest4 and Tcest6 were significantly induced from 12 to 72 h. RNAi against Tcest4 or Tcest6 led to the higher mortality compared with the controls after the insecticides treatment, suggesting that these two genes play a vital role in detoxification of insecticides in T. castaneum. Furthermore, with insecticides exposure to Tclph knockdown beetles, the expression of Tcest4 was upregulated but Tcest6 was downregulated, indicating that beetles existed a compensatory response against the insecticides. Additionally, RNAi of Tcest6 resulted in 43% reductions in female egg laying and completely inhibited egg hatching, which showed the similar phenotype as that of Tclph knockdown. These results indicated that Tclph affected fecundity by positively regulating Tcest6 expression. Our findings will provide a new insight into the molecular mechanisms of Tclph involved in physiological functions in T. castaneum.

scholarly journals Seasonal Patterns of Singing Activity Vary With Time of day in The Nightingale (Luscinia Megarhynchos)

The Auk ◽  
2004 ◽  
Vol 121 (1) ◽  
pp. 110-117 ◽  
Author(s):  
Valentin Amrhein ◽  
Hansjoerg P. Kunc ◽  
Marc Naguib
Keyword(s):  
Seasonal Pattern ◽  
Time Of Day ◽  
Egg Laying ◽  
Breeding Cycle ◽  
Seasonal Patterns ◽  
Singing Behavior ◽  
The Social ◽  
Luscinia Megarhynchos ◽  
Singing Activity ◽  
Late Stages

Abstract Seasonal patterns of singing activity of male birds have been thoroughly studied, but little is known about how those patterns vary with time of day. Here, we censused mated and unmated male Nightingales (Luscinia megarhynchos) at four different hours of the day throughout the breeding cycle. In unmated males, singing activity increased until the young hatched in their neighborhood, and the seasonal variation was similar at each of the four hours of the day. In mated males, however, the seasonal patterns of singing activity differed between hours of the day. In morning (about the hour of egg-laying) and during the dusk chorus, the singing activity of mated males was strongly influenced by the females' reproductive state: singing activity was low before egg-laying and during incubation, but high during the egg-laying period. In the dawn chorus, however, singing activity showed a similar seasonal pattern in mated and unmated males and was high until late stages of the breeding cycle. Our results suggest that the social context influences singing behavior to a varying degree across the season, and that this variation also depends on time of day. The hour of data collection thus is an important but often neglected factor when seasonal changes of singing activity are studied.

Opposite Changes in Plasma Testosterone and Corticosterone Levels Following a Simulated Territorial Challenge in Male Great Tits

Behaviour ◽  
2004 ◽  
Vol 141 (4) ◽  
pp. 451-467 ◽  
Author(s):  
Rianne Pinxten ◽  
Lutgarde Arckens ◽  
Els van Duyse ◽  
Marcel Eens ◽  
Veerle Darras
Keyword(s):  
Parus Major ◽  
Time Of Day ◽  
Behavioural Response ◽  
Egg Laying ◽  
Plasma Testosterone ◽  
Breeding Cycle ◽  
Territorial Defence ◽  
Breeding Stage ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion

AbstractThe apparent ability of plasma testosterone (T) and corticosterone (B) levels to fluctuate rapidly in response to agonistic interactions, suggests that these hormones may play an important role in an animal's acute behavioural response during such interactions. In the present study, free-living male great tits, Parus major, were subjected to a simulated territorial intrusion (STI) during the egg laying, incubation and nestling stage of first broods. Plasma T and B levels of challenged males were compared to those of control males matched for breeding stage, day in breeding stage, and time of day. Plasma B levels were significantly higher in challenged males compared to control males during the egg laying and incubation stage but not during the nestling stage. On the other hand, challenged males had significantly lower plasma T levels than control males throughout the breeding cycle. While having low plasma T and elevated plasma B levels, challenged males showed a vigorous and unrelenting territorial response to the STI. Plasma T and B levels of challenged males did not correlate with the intensity of the behavioural response to the STI. These findings do not agree with the predictions of the 'challenge hypothesis' that males exposed to a territorial challenge while having breeding baseline T levels will respond with an increase in T or that T correlates with the intensity of aggression during a challenge. Together, our findings suggest a role for B rather than T in the regulation of territorial defence in male great tits.

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