Number of Pairs, Timing of Egg-Laying and Clutch Size in a Subalpine Sand Martin Riparia riparia Colony, 1968-1985

1986 ◽  
Vol 17 (3) ◽  
pp. 221 ◽  
Author(s):  
Soren Svensson

2008 ◽  
Vol 4 (6) ◽  
pp. 606-609 ◽  
Author(s):  
Dik Heg

Suppression by dominants of female subordinate reproduction has been found in many vertebrate social groups, but has rarely been shown experimentally. Here experimental evidence is provided for reproductive suppression in the group-living Lake Tanganyika cichlid Neolamprologus pulcher . Within groups of three unrelated females, suppression was due to medium- and small-sized females laying less frequently compared with large females, and compared with medium females in control pairs. Clutch size and average egg mass of all females depended on body size, but not on rank. In a second step, a large female was removed from the group and a very small female was added to keep the group size constant. The medium females immediately seized the dominant breeding position in the group and started to reproduce as frequently as control pairs, whereas clutch size and egg mass did not change. These results show that female subordinate cichlids are reproductively capable, but apparently suppressed with respect to egg laying. Nevertheless, some reproduction is tolerated, possibly to ensure continued alloparental care by subordinate females.



Author(s):  
E.N. Kondratyev ◽  

Today, global climate changes are taking place, leading to changes in the habitats of many species, including organisms of epidemiological importance. The transfer of such organisms will primarily involve the blood-sucking parasites of migratory birds. The sand martin (Riparia riparia Linnaeus, 1758) is one of many migratory birds nesting in the Saratov region. In order to understand how much the species is involved in the transmission of infection and the creation of a new focal point of infection, it is necessary to establish the taxonomic structure of the nidicol fauna.



2019 ◽  
Vol 161 (1) ◽  
pp. 243-255 ◽  
Author(s):  
Zoë Rohrer ◽  
Salvador Rebollo ◽  
Enrique Andivia ◽  
Carlos Rodríguez ◽  
Juan Franco


PLoS ONE ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. e0209737 ◽  
Author(s):  
Tibor Szép ◽  
János Dobránszky ◽  
Anders Pape Møller ◽  
Gareth Dyke ◽  
Ádám Z. Lendvai


1995 ◽  
Vol 73 (9) ◽  
pp. 1579-1587 ◽  
Author(s):  
Gregory J. Robertson

Annual variation in volumes of eggs laid by common eiders (Somateria mollissima sedentaria) nesting at La Pérouse Bay, Manitoba (58°43′N, 93°27′W), was studied over 3 years (1991–1993). Temperatures during the egg-laying period were higher in 1991 than in 1992 and 1993. However, the eiders began nesting in 1993 at the same time as in 1991, whereas in 1992 the eiders began laying approximately 2 weeks later. Eiders laid significantly smaller clutches in 1992 than in the other 2 years. Egg size did not correlate with clutch size or laying date in any year. However, eiders laid smaller eggs in 1992 and 1993 than in 1991. In five egg clutches, the pattern of intraclutch egg-size variation was different among years. The last laid eggs of five egg clutches were disproportionately smaller in 1992 and 1993 (cold years) than those laid in 1991. Minimum daily temperatures before the egg-laying period (during rapid yolk development) were positively correlated with egg size. However, this effect was not significant when year and egg sequence were controlled for. Egg-size variation was correlated with the overall ambient temperatures during the laying period, whereas annual clutch-size variation was correlated with laying date, suggesting that the proximate mechanisms affecting clutch and egg size are different.





The Condor ◽  
1987 ◽  
Vol 89 (2) ◽  
pp. 369 ◽  
Author(s):  
Douglas B. McNair
Keyword(s):  


2012 ◽  
Vol 58 (6) ◽  
pp. 820-827 ◽  
Author(s):  
Long-Hui Lin ◽  
Fei Mao ◽  
Ce Chen ◽  
Xiang Ji

Abstract We collected gravid gray rat snakes Ptyas korros from three geographically distinct populations in China, Chenzhou (CZ), Jiangshan (JS) and Dinghai (DH), to study geographical variation in female reproductive traits. Egg-laying dates differed among the three populations such that at the most northern latitude egg-laying was latest, and earliest at the most southern lati-tutde. Clutch size, clutch mass, egg mass, egg shape, within clutch variability in egg sizes and relative clutch mass differed among the three populations, whereas post-oviposition body mass did not. Except for egg-laying date, none of the traits examined varied in a geographically continuous trend. CZ and DH females, although separated by a distance of approximately 1100 km as the crow flies, were similar in nearly all traits examined. JS females were distinguished from CZ and DH females by their higher fecundity (clutch size), greater reproductive output (clutch mass) and more rounded eggs. Our data do not validate the prediction that larger offspring should be produced in colder localities. The absence of an egg size-number trade-off in each of the three populations presumably suggests that P. korros is among species where eggs are well optimized for size within a population.



Ibis ◽  
1997 ◽  
Vol 139 (3) ◽  
pp. 494-496 ◽  
Author(s):  
MARIA ALICE SANTOS ALVES
Keyword(s):  


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