scholarly journals SEX RATIO, BODY SIZE AND SEASONALITY IN A SOLITARY BEE, OSMIA LIGNARIA PROPINQUA CRESSON (HYMENOPTERA: MEGACHILIDAE)

Evolution ◽  
1980 ◽  
Vol 34 (5) ◽  
pp. 993-1003 ◽  
Author(s):  
P. F. Torchio ◽  
V. J. Tepedino
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Solitary Bee ◽  
Osmia Lignaria

II.—Hidden Divergence in Laboratory Strains of Drosophila pseudo-obscura

1944 ◽  
Vol 62 (1) ◽  
pp. 9-19 ◽  
Author(s):  
Rowena Lamy
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Genetic Constitution ◽  
Low Grade ◽  
Testis Size ◽  
Hybrid Female ◽  
Back Cross ◽  
Pure Race ◽  
Range Of Variation

The Race A/Race B hybrid females of D. pseudo-obscura have a high percentage of fertility, comparable with that of females of pure race. The number and viability of their offspring, however, are largely affected by the genetic constitution of the hybrid female as well as by that of the male to which she is mated in the backcross. Hence the performance of any given hybrid is determined in the first instance by the actual strains of the pure races which are used in making the P1 racial cross. Generally speaking the results are of the same order whenever the same strains are used. The progenies of hybrid females of different genetic constitution may differ in three main aspects: (1) The total number of offspring may be comparable with that usually obtained in a pure race cross; it may be reduced to any extent; in certain matings it is consistently at zero. (2) The sex ratio may be completely normal or male-deficient or female-deficient in any degree; completely uni-sexual progenies are sometimes obtained. (The above observations are mainly in agreement with reports of earlier writers; cf. Lancefield, 1929, Dobzhansky, 1936, Mampell, 1941, Sturtevant, 1937.) (3) “Viability characters,” i.e. those affecting general vigour and physical normality, may be of a high or a low grade; some progenies are comparable in this respect with the pure race, the only exception being that they show a much greater range of variation in body-size of both sexes, and in the testis size of males, abnormalities which are common to all back-cross progenies whatever the genetic constitution of the mother or father. Some progenies show in addition deformities of a peculiar type usually affecting the abdomen and occasionally the legs and wings.

Variation in Weight, Size, and Sex Ratio of Coccinellid Adults (Coleoptera: Coccinellidae)

1966 ◽  
Vol 98 (6) ◽  
pp. 639-644 ◽  
Author(s):  
B. C. Smith
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Water Content ◽  
Food Supply ◽  
Sexual Differences ◽  
Intraspecies Variation ◽  
Food Scarcity ◽  
Food Requirement ◽  
Males And Females

AbstractThe weight and size of coccinellid adults varied with species, sex, and feeding. Intraspecies variation in weight was generally similar in the eight species studied. Females were more variable than males in body size. Females of some species were heavier and larger than males, and species can be classified on a basis of difference in the weight and size of the sexes.An increase in the food supply after a period of food scarcity affected the sex ratio, as the minimum food requirement of females was greater than males. Females increased in weight more rapidly than males after feeding. The availability of food in the field affected the weight and size of some species. Adult water content was influenced by feeding but not by sex or the quantity of food given to the larva.Males were more abundant in species with small sexual differences in weight and size. The degree of difference in weight and size between males and females may be used as a criterion to select species that are best adapted to survive when food is scarce.

scholarly journals Emergence ecology of the critically endangered Urothemis edwardsii in a new colonized site in El Kala National Park (Algeria): conservation implications

2019 ◽  
pp. 137-142
Author(s):  
Baaloudj Affef
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Sexual Size Dimorphism ◽  
The Body ◽  
Microhabitat Selection ◽  
Conservation Implications ◽  
And Behavior ◽  
The Relationship ◽  
The Vertical Distribution ◽  
Dragonfly Species

Urothemis edwardsii is one of the most threatened dragonfly species in the Mediterranean. Recent investigations and conservation efforts have increased the local geographic distribution of the species in Northeast Algeria, where a new population (named El Graeate) has been discovered. In the absence of information about the biology and behavior of U. edwardsii in this new site, a study was conducted on the emergence ecology of the species taking into account the temporal pattern of emergence, sex ratio, body size and microhabitat selection. Emergence, which was quite asynchronous, lasted for 50 days, with 50% of the population emerging within the first half of the period. Sex ratio at emergence was slightly female biased despite the absence of sexual size dimorphism, suggesting that size is not the only driving force behind mortality bias during the larval stage. There was a slight seasonal increase in the body size of exuviae (exoskeletons) in both sexes. Microhabitat selection, assessed as the vertical stratification of exuviae at ecdysis, was positively correlated with the height of supporting plants, but the relationship reached a plateau suggesting that there are predetermined limits to the vertical distribution of exuviae. These data will be essential for the future species protection, restoration and management attempts in the region.

‘Photography’ as a useful method for estimating the density, sex-ratio and body size of the surface-active Austruca perplexa (H. Milne Edwards, 1852) (Brachyura, Ocypodidae)

Crustaceana ◽  
2021 ◽  
Vol 94 (11-12) ◽  
pp. 1429-1440
Author(s):  
Kanitta Keeratipattarakarn ◽  
Fahmida Wazed Tina ◽  
Rattapon Sangngam ◽  
Ketsanee Thongsri ◽  
Arreeya Suphap
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Fiddler Crab ◽  
Body Sizes ◽  
Crab Density ◽  
Surface Active ◽  
Non Destructive ◽  
Photography Method

Abstract Estimations of crab density, sex-ratio, and body sizes are difficult. Though the ‘burrow excavation’ method is widely used to estimate these parameters in surface-active crabs, it is destructive to crab populations. Therefore, an alternative, non-destructive method is desirable. This study compared the non-destructive ‘photography’ method with the ‘burrow excavation’ method in a fiddler crab (Austruca perplexa (H. Milne Edwards, 1852)) population. Twenty 0.25 m2 quadrats were set out and 4 photos were taken of the surface-active crabs in each quadrat. All crab burrows were then excavated, and the crabs were collected to estimate their numbers, sexes, and body and claw sizes. Afterward, the photographs were analysed to estimate the same parameters by using the GIMP program. These parameters were then compared between the two methods. The results showed that these parameters were not different between the methods compared. This study thus reveals that the ‘photography’ method could safely be used instead of the ‘burrow excavation’ method, and yield the same results.

Size-dependent seasonal activity for males of the dung beetle Copris acutidens (Coleoptera: Scarabaeidae)

2019 ◽  
Vol 151 (6) ◽  
pp. 757-767 ◽  
Author(s):  
Mayumi Akamine
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Dung Beetle ◽  
Threshold Value ◽  
Reproductive Period ◽  
Seasonal Activity ◽  
Size Dependent ◽  
Horn Length ◽  
Female Bias ◽  
Early Activity

AbstractThis study aimed to determine differences in activities between two male morphs of the dung beetle Copris acutidens Motschulsky (Coleoptera: Scarabaeidae) during the reproductive period and to examine the size distribution of reproductive males that stayed in nests. The activities of two male morphs distinguished by a threshold value of body size were compared with those by horn length. Regardless of body size or horn length, earlier activity of minor males was observed during the reproductive period. The sex ratio showed the greatest female bias when minor males were the more abundant than major males, indicating that minor males were the most active when competition was the weakest and these could avoid direct combat with major males. In morphs distinguished by horn length, more major males than minor males stayed in nests with females although the major males became the most active from the middle of the reproductive period. Thus, longer horns may directly confer a competitive advantage to males, enabling them to stay in nests with females, whereas early activity of minor males does not always indicate the effect of horn length directly. Therefore, this behaviour may occur regardless of whether the morphs differ in body size or horn length.

Body size variation in hybrids among populations of European water frogs (Pelophylax esculentus complex) with different breeding systems

2020 ◽  
Vol 41 (3) ◽  
pp. 361-371
Author(s):  
Adam Hermaniuk ◽  
Magdalena Czajkowska ◽  
Anetta Borkowska ◽  
Jan R.E. Taylor
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Parental Species ◽  
Size Variation ◽  
Breeding Systems ◽  
European Water ◽  
Water Frogs ◽  
Population Type ◽  
Pelophylax Esculentus ◽  
European Water Frogs

Abstract In some populations, hybrids reproduce with a parental species by eliminating the genome of this species from their own germline and produce gametes that only contain the genome of the other parental species (sexual host). This mode of reproduction, known as hybridogenesis, leads to a conflict of interest between the two parties because the sexual host should avoid mating with the hybrid to prevent a reduction in reproductive success, whereas the hybrid depends on such matings for survival. We investigated European water frogs (Pelophylax esculentus complex), including hybrids (P. esculentus, genotype LR) and two sexual host species (P. lessonae, LL and P. ridibundus, RR). We hypothesized that to maximize fitness, hybrid males should be morphologically more similar to the sexual host that is preferred by females for successful reproduction. To test this hypothesis, we compared hybrid males in two different population types, L-E (hybrids coexist with LL) and L-E-R (hybrids coexist with both LL and RR). The latter was described in terms of genome composition, sex ratio, and mate choice preferences; the sex ratio of hybrids was significantly male-biased. We found that LR males from the L-E-R populations were significantly larger than those from the L-E, which makes them more similar to P. ridibundus, the largest species within the P. esculentus complex. We suggest that a larger body size of hybrid males may provide a reproductive advantage in the L-E-R population type, where the most common type of pair caught in the breeding season was LR males × RR females.

scholarly journals Brood Sex Ratios are Related to Male Size but not to Attractiveness in Common Yellowthroats (Geothlypis Trichas)

The Auk ◽  
2007 ◽  
Vol 124 (1) ◽  
pp. 176-184 ◽  
Author(s):  
Betsy Abroe ◽  
Julia C. Garvin ◽  
Marc C. Pedersen ◽  
Linda A. Whittingham ◽  
Peter O. Dunn
Keyword(s):  
Body Size ◽  
Sex Ratio ◽  
Reproductive Value ◽  
Male Body ◽  
Male Size ◽  
Common Yellowthroat ◽  
Geothlypis Trichas ◽  
The Common ◽  
Fitness Benefits ◽  
Male Ornament

Abstract When the reproductive value of sons differs from that of daughters, selection will favor broods biased toward the sex that can provide greater fitness benefits. In species where female choice is based on male ornamentation, females mated to highly ornamented males may experience a reproductive advantage by skewing the brood sex ratio toward sons. In the Common Yellowthroat (Geothlypis trichas), males with larger black facial masks are more likely to gain a social mate and sire extrapair young and, as a result, have increased seasonal reproductive success. Females mated to larger-masked males could benefit if they produced more sons. Given that larger- masked males are preferred as extrapair sires, females may also benefit by producing more extrapair sons. We tested these hypotheses during a five-year study of Common Yellowthroats in Wisconsin. Contrary to our predictions, females did not produce more sons when mated to males with larger masks, and extrapair young were not more likely to be male. However, sons were more likely to be sired by males with longer tarsi, which suggests that females may respond to male body size rather than to male ornament size. El Cociente de Sexos en las Nidadas Está Relacionado con el Tamaño de los Machos pero no con el Atractivo en Geothlypis trichas

scholarly journals Reproductive potential and nesting effects of Osmia rufa (syn. bicornis) female (Hymenoptera: Megachilidae)

2016 ◽  
Vol 60 (1) ◽  
pp. 75-86 ◽  
Author(s):  
Karol Giejdasz ◽  
Monika Fliszkiewicz ◽  
Andrea Bednárová ◽  
Natraj Krishnan
Keyword(s):  
Sex Ratio ◽  
Reproductive Potential ◽  
Female Offspring ◽  
Male Offspring ◽  
Nesting Behavior ◽  
Solitary Bee ◽  
Male And Female ◽  
Individual Female ◽  
The Family ◽  
Number Of Cells

Abstract The red mason bee Osmia rufa is a solitary bee belonging to the family Megachilidae, and is prone to nest in aggregations. Each female builds a nest separately in pre-existing cavities such as holes in wood and walls or empty plant stems. This is done by successively setting the cells in a linear series. In this study, we elucidate the nesting behavior and the reproductive potential of a single O. rufa female. The reproductive potential of nesting females was evaluated after the offspring finished development. We observed that an individual female may colonize up to five nest tubes and build 5-34 cells in them (16 on an average). During the nesting time the number of cells decreased with the sequence of nest tubes colonized by one female, which built a maximum of 11 cells in the first occupied nest and 5 cells in the last (fifth nest). Our observations indicated that 40% of nesting females colonized one nest tube as compared to 7% colonizing five nest tubes. Furthermore, in subsequent nest tubes the number of cells with freshly emerged females gradually decreased which was the reverse with males. Thus, the sex ratio (proportion of male and female offspring) may change during the nesting period. The female offspring predominated in the first two nesting tubes, while in the subsequent three tubes male offspring dominated. We also cataloged different causes of reduction in abundance of offspring in O. rufa females such as parasitization or problem associated with moulting.

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