One or two eggs: what underlies clutch size variation within a gecko species?

SummaryThe Raso Lark Alauda razae is a single island endemic confined to the island of Raso in the Cape Verde islands. It has been studied via short (11–20 day), similarly-timed visits every year from 2001 to 2017. These November/December visits have occurred towards the end of the main rainy period (August–October) in the Cape Verdes. Average clutch size ranged from zero (no nests found) to 3.57 in different years and was strongly correlated with rainfall in the three months preceding the year’s visit, but not with population size, which varied 25-fold during the study period. Since the nomadic pursuit of rain is not an option for the Raso Lark, the species adjusts clutch size according to conditions prevailing on Raso.

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Annual variation in common eider egg size: effects of temperature, clutch size, laying date, and laying sequence

Canadian Journal of Zoology ◽

10.1139/z95-188 ◽

1995 ◽

Vol 73 (9) ◽

pp. 1579-1587 ◽

Cited By ~ 24

Author(s):

Gregory J. Robertson

Keyword(s):

Clutch Size ◽

Egg Size ◽

Annual Variation ◽

Size Variation ◽

Egg Laying ◽

Laying Date ◽

Somateria Mollissima ◽

Ambient Temperatures ◽

Common Eiders ◽

N 93

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.

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Egg size and clutch size in three species of Nihonotrypaea (Decapoda: Thalassinidea: Callianassidae) from western Kyushu, Japan

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315406012902 ◽

2006 ◽

Vol 86 (1) ◽

pp. 103-111 ◽

Cited By ~ 12

Author(s):

K. Kubo ◽

K. Shimoda ◽

A. Tamaki

Keyword(s):

Clutch Size ◽

Egg Size ◽

Relative Size ◽

Size Variation ◽

Middle Part ◽

Reproductive Period ◽

Late Winter ◽

Estuarine System ◽

Ariake Sound ◽

Interspecific Comparisons

Three species of the callianassid genus Nihonotrypaea occur in the Ariake Sound estuarine system, southern Japan; they consist of two tidal-flat species (N. harmandi; N. japonica) and one boulder-beach species (N. petalura), with maximum population densities of 1440, 343, and 12 ind m−2, respectively. Nihonotrypaea harmandi and N. petalura are distributed along the coastline from the outermost part of the sound to the open sea, while N. japonica occurs in the middle part of the sound. Nihonotrypaea japonica has an extended reproductive period from late winter to autumn, while those of the other species are from late spring or summer to autumn. Interspecific comparisons were made for recently laid egg size (as volume) and clutch size (as number of eggs per female). Only in N. japonica was a seasonal egg size variation observed, being significantly larger in winter to spring (mean=0.106 mm3) than in summer (0.080 mm3). By contrast, clutch size was significantly smaller in winter to spring, resulting in nearly the same clutch volume per female (product of the mean egg volume and clutch size) between the seasons. Among the three species, the egg size was ordered as N. japonica (overall mean volume through the seasons=0.092 mm3)>>N. petalura (0.057 mm3)>N. harmandi (0.054 mm3). The clutch size was ordered as N. harmandi>N. petalura≈N. japonica. The clutch volume was ordered as N. japonica≈N. harmandi>N. petalura. The smallest clutch volume value for N. petalura female showed an opposite trend to the relative size of the major cheliped found in a previous study.

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Within-clutch egg-size variation in a subsocial bug: the positional effect hypothesis

Canadian Journal of Zoology ◽

10.1139/z06-163 ◽

2006 ◽

Vol 84 (11) ◽

pp. 1540-1544 ◽

Cited By ~ 11

Author(s):

Shin-ichi Kudo

Keyword(s):

Predation Risk ◽

Clutch Size ◽

Egg Size ◽

Size Variation ◽

Instar Nymph ◽

Offspring Size ◽

Egg Mass ◽

Female Body Size ◽

Positional Effect ◽

Effect Hypothesis

If there are differences in predation risk among the offspring within a clutch, parents should allocate less resources to the offspring facing higher risk. Predation risk, and thus offspring size, may depend on the spatial position of individual offspring within a clutch. To test this positional effect hypothesis, I examined egg-size (egg-mass) variation in the subsocial bug Elasmucha signoreti Scott, 1874 (Hemiptera: Acanthosomatidae). In subsocial insects, including Elasmucha , in which females guard their clutches against predators by covering the clutch with their bodies, there are large differences in survival between offspring at the centre and at the periphery of the clutch. There was considerable variation in reproductive output among females; female body size was positively correlated with egg mass but not with clutch size. Females laid significantly lighter eggs in the peripheral, and thus more vulnerable, part of the clutch. No phenotypic trade-off between egg mass and clutch size was detected. Egg mass was positively correlated with hatched first-instar nymph mass. Thus, E. signoreti females seem to allocate their resources according to the different predation risks faced by the offspring within a clutch. I suggest that the positional effect hypothesis can generally be applicable to species whose females lay eggs in clutches and that the eggs suffer different mortality rates which depend on their spatial positions within the clutch.

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Factors affecting egg viability and incubation time in prairie dabbling ducks

Canadian Journal of Zoology ◽

10.1139/z93-156 ◽

1993 ◽

Vol 71 (6) ◽

pp. 1146-1152 ◽

Cited By ~ 43

Author(s):

Todd W. Arnold

Keyword(s):

Clutch Size ◽

Incubation Time ◽

Egg Size ◽

Hatching Success ◽

Size Variation ◽

Negative Effects ◽

Factors Affecting ◽

Ambient Temperatures ◽

Weak Support ◽

Anas Clypeata

I determined hatching success for 328 dabbling duck (Anas spp.) eggs that were experimentally subjected to varying lengths of preincubation delay and then artificially incubated. Hatchability declined as unincubated eggs were exposed to longer preincubation delays. This effect was more pronounced at higher ambient temperatures and later in the nesting season, but did not vary with egg size or among duck species. These results are largely consistent with observed patterns of clutch-size variation among prairie-nesting waterfowl. Clutch size may be smaller later in the year and at lower latitudes owing to the negative effects of date and temperature on the ability of eggs to withstand preincubation delay. The timing of embryo mortality was bimodal, with peaks occurring during early development (<6 d) and just before hatching (>22 d); however, only early mortality was affected by preincubation delay. Eggs lost up to 2.6% of their initial mass as water vapor during preincubation delay, but the amount of water loss did not affect hatching success. Eggs subjected to preincubation delay required about 1 additional day to hatch. Incubation time was related to egg size in northern shovelers (Anas clypeata) and in all species combined, but not in blue-winged teal (Anas discors) or mallards (Anasplatyrhynchos). These data provide only weak support for the hypothesis that large eggs are costly because they take longer to hatch.

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Clutch Size Variation of Birds in Relation to Nest Predation: On the Cost of Reproduction

Journal of Animal Ecology ◽

10.2307/4669 ◽

1984 ◽

Vol 53 (3) ◽

pp. 945 ◽

Cited By ~ 113

Author(s):

Tore Slagsvold

Keyword(s):

Clutch Size ◽

Nest Predation ◽

Size Variation ◽

Cost Of Reproduction ◽

The Cost

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Clutch size variation and morphology in a cyclomorphic Bosmina population

Journal of Plankton Research ◽

10.1093/plankt/24.7.653 ◽

2002 ◽

Vol 24 (7) ◽

pp. 653-659 ◽

Cited By ~ 6

Author(s):

R. Lagergren

Keyword(s):

Clutch Size ◽

Size Variation

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Egg size, contents, and quality: maternal-age and -size effects on house fly eggs

Canadian Journal of Zoology ◽

10.1139/z00-086 ◽

2000 ◽

Vol 78 (9) ◽

pp. 1544-1551 ◽

Cited By ~ 35

Author(s):

G S McIntyre ◽

R H Gooding

Keyword(s):

Clutch Size ◽

Size Effects ◽

Maternal Age ◽

Egg Size ◽

Egg Quality ◽

Size Variation ◽

House Fly ◽

Egg Volume ◽

Hatch Rate ◽

Maternal Size

Egg size is generally regarded as a good predictor of egg quality. However, in phenotypic studies it is difficult to separate the effects of egg-size variation from the effects of the underlying cause of the differences in egg size. We examined the relationships between the size, shape, hatch rate, and biochemical and energy contents of house fly (Musca domestica L.) eggs using two distinct sources of egg-size variation: maternal age and maternal size. By comparing relationships among egg parameters between manipulations we were able to distinguish some maternal effects from pure egg-size effects. Maternal age was negatively correlated with clutch size, egg volume, hatch rate, and lipid content, but was not correlated with protein, carbohydrate, or energy content. Female size did not affect hatch rate or biochemical and energy contents, but was positively correlated with clutch size and egg volume. Partial correlation analyses revealed that egg-size variation due to maternal-age effects was unrelated to hatch rate, but that egg-size variation due to maternal-size effects was weakly negatively correlated with hatch rate. The results suggest that large and small house fly eggs differ primarily in size and that within size classes there is significant variation in other egg parameters. Size is not a useful predictor of egg quality in this system.

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