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

Author(s):  
K. Kubo ◽  
K. Shimoda ◽  
A. Tamaki

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.

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.


2006 ◽  
Vol 84 (11) ◽  
pp. 1540-1544 ◽  
Author(s):  
Shin-ichi Kudo

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.


1993 ◽  
Vol 71 (6) ◽  
pp. 1146-1152 ◽  
Author(s):  
Todd W. Arnold

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.


The Auk ◽  
1984 ◽  
Vol 101 (4) ◽  
pp. 685-697 ◽  
Author(s):  
Tore Slagsvold ◽  
Jostein Sandvik ◽  
Gunnar Rofstad ◽  
Öystein Lorentsen ◽  
Magne Husby

AbstractUsing data from the field and the literature on 67 species of birds, we analyzed intraclutch variation in egg size, especially the deviation of the last egg from the clutch mean (D). Values of D are closer to zero in precocial than in altricial species; D is negatively correlated with body size in interspecific comparisons, i.e. large birds, including precocial species, lay small final eggs; and D is higher in open-nesting passerines (on average D = +3.56%, 17 species) than in hole-nesting species (on average D = -0.05%, 13 species). Within populations of birds, a negative relationship exists between D and clutch size, particularly in species that have a generally low value of D. The results support the view that intraclutch variation in egg size has an ultimate, adaptive value. We suggest that birds adopting the "brood-reduction strategy" have a small final egg, particularly those birds with large clutches, whereas birds adopting the "brood-survival strategy" have a relatively large final egg, particularly those birds with large clutches.


2000 ◽  
Vol 78 (9) ◽  
pp. 1544-1551 ◽  
Author(s):  
G S McIntyre ◽  
R H Gooding

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.


Ornis Svecica ◽  
2010 ◽  
Vol 20 (2) ◽  
Author(s):  
Marcin Polak

The main aim of this study was to examine how clutch size and season influenced egg size in a population of Marsh Harriers Circus aeruginosus in eastern Poland. The Marsh Harriers nested in small, isolated patches of reed belts surrounding fish ponds. A total of 328 eggs from 70 clutches were measured during four nesting seasons (2005–2008). Average clutch size was 4.69 ± 0.71 eggs and did not vary between years; the modal clutch size was 5 eggs. Mean values of the egg dimensions were: egg length = 48.60 ± 1.78 mm; egg breadth = 38.36 ± 1.13 mm; egg volume = 36.53 ± 2.99 cm3. There was a strong correlation between egg length and egg breadth. The number of eggs in a clutch had no effect on the egg size.


2017 ◽  
Vol 38 (4) ◽  
pp. 425-434
Author(s):  
Priscila Silva Lucas ◽  
Alex Bager

Reproductive traits and the level of parental investment in offspring varies between individuals and species. These are central issues in life history theory and evolutionary biology. Maternal body size plays an important role in reproduction, and we usually observe variable investment in offspring by females. Thus, optimal egg size may not be reached in some populations or species. In this study, we tested if reproductive traits differed between populations of D’Orbigny’s slider in a specific geographical area in Brazil. We evaluated the relationship between reproductive traits to maternal body size and clutch size to egg size to determine possible trade-offs across populations. At the population level, maternal body size and reproductive traits of D’Orbigny’s slider were different even in geographically nearby areas. Maternal body size had a positive effect on clutch size, but not on egg size, except in the Arroio Grande population. Nevertheless, we did not observe a negative correlation between clutch and egg size in any population. Although maternal body size had effects in the different populations explaining most of the variation of clutch size, variation in egg size may be the result of decreased survival chances in unpredictable environments and possibly morphological constraints. The trade-off between egg size and number was not observed and this could be expected if resource availability and reproductive allocation by females vary greatly among individuals.


1985 ◽  
Vol 16 (2) ◽  
pp. 88 ◽  
Author(s):  
Kjell Einar Erikstad ◽  
Hans Chr. Pedersen ◽  
Johan B. Steen

The Auk ◽  
2001 ◽  
Vol 118 (2) ◽  
pp. 500-503 ◽  
Author(s):  
Paul L. Flint ◽  
Robert F. Rockwell ◽  
James S. Sedinger

Abstract Measures of repeatability have long been used to assess patterns of variation in egg size within and among females. We compared different analytical approaches for estimating repeatability of egg size of Black Brant. Separate estimates of repeatability for eggs of each clutch size and laying sequence number varied from 0.49 to 0.64. We suggest that using the averaging egg size within clutches results in underestimation of variation within females and thereby overestimates repeatability. We recommend a nested design that partitions egg-size variation within clutches, among clutches within females, and among females. We demonstrate little variation in estimates of repeatability resulting from a nested model controlling for egg laying sequence and a nested model in which we assumed laying sequence was unknown.


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