Communal Nesting in the Digger Wasp Cerceris australis (Hymenoptera : Sphecidae)

Study of 39 nests of Cerceris australis at nine localities in eastern Australia has demonstrated that most nests are occupied by two or three successive generations of wasps and may ultimately contain well over 100 cells. Nests are dug deep in the soil and are provisioned with scarab beetles, which are allowed to accumulate in the burrow before from two to six are placed in a cell. Nests are usually occupied by several females, some of which are provisioners, bringing in beetles day after day and each time leaving the nest usually after only a few seconds, and others are non-provisioners, leaving the nest for a short period once a day and returning without prey. During the day, nest entrances are occupied by females (believed to be usually non-provisioners) stationed facing out; they are effective in deterring the entry of ants and mutillids. The factors that determine what role a female will play remain obscure. Both provisioners and non-provisioners show progressive mandibular wear as well as essentially similar ovarian development; there are no consistent differences in body size between members of the two groups. In any one nest, considerable variation in the appearance of the ovaries is apparent, and oosorption appears to be common. More than one female often appears to be in egg-laying condition, and the fact that cooperating provisioners bring in enough beetles each day to provision several cells suggests that more than one female lays an egg each day. However, the presence of oocytes in various stages of resorption suggests that in some individuals oviposition is suppressed. No correlation was found between extent of oosorption and the provisioner-nonprovisioner dichotomy. The necessity to guard these large, multicellular nests from parasitoids and predators has evidently brought about selection for the development of a caste of guards which, however, continue to play a role in nest construction and presumably in laying eggs on beetles provided by other females.

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A uni- and multivariate analysis approach to reveal sexual size dimorphism in Iranian populations of Hypera postica (Coleoptera: Curculionidae)

Biologia ◽

10.1515/biolog-2015-0137 ◽

2015 ◽

Vol 70 (9) ◽

pp. 1228-1233 ◽

Cited By ~ 3

Author(s):

Ehsan Sanaei ◽

Marjan Seiedy ◽

Farzaneh Momtazi

Keyword(s):

Body Size ◽

Sexual Size Dimorphism ◽

Egg Laying ◽

Morphological Divergence ◽

High Fecundity ◽

Hypera Postica ◽

Size Dimorphism ◽

Female Body Size ◽

Divergence Pattern ◽

Iranian Populations

Abstract Body size dimorphism between genders is a commonly observed phenomenon in insects, usually manifested in larger female body size. Sexual Size Dimorphism (SSD) varies from species to species, the degree and direction influenced by certain evolutionary pressures. Intraspecific variation in SSD may also occur between populations. The Hypera postica (Gyllenhal, 1813) is a well-known alfalfa plant pest that shows a degree of morphological divergence in its populations. The female alfalfa weevils are very fecund and have a larger body size compared to males. To improve our knowledge on magnitude and direction of SSD in alfalfa weevil, we studied 200 specimens of H. postica from four Iranian populations (Karaj1, Karaj2, Tuyserkan and Jovein). 10 morphological variables from three external anatomic parts (pronotum, elytra and rostrum) and 45 ratio characters were statistically analyzed in order to determine the amount of SSD in Iranian populations. In addition we investigated for morphological divergence pattern in mentioned populations. The results of this study show that a low degree of morphological divergence occurs in Iranian populations. Measured variables indicate that the SSD pattern of H. postica is compatible with the Rensch’s rule, and is related to high fecundity of females and a lack of strong sexual selection. Also it is mentioned that the larger rostrum in females may correspond to its unique role in egg laying.

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Atmospheric Hypoxia Limits Selection for Large Body Size in Insects

PLoS ONE ◽

10.1371/journal.pone.0003876 ◽

2009 ◽

Vol 4 (1) ◽

pp. e3876 ◽

Cited By ~ 35

Author(s):

C. Jaco Klok ◽

Jon F. Harrison

Keyword(s):

Body Size ◽

Large Body ◽

Large Body Size ◽

Selection For

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Continued artificial selection for running endurance in rats is associated with improved lung function

Journal of Applied Physiology ◽

10.1152/japplphysiol.90419.2008 ◽

2009 ◽

Vol 106 (6) ◽

pp. 1810-1818 ◽

Cited By ~ 22

Author(s):

Scott D. Kirkton ◽

Richard A. Howlett ◽

Norberto C. Gonzalez ◽

Patrick G. Giuliano ◽

Steven L. Britton ◽

...

Keyword(s):

Body Size ◽

Lung Volume ◽

Maximal Oxygen Consumption ◽

Endurance Capacity ◽

Endurance Running ◽

Body Frame ◽

Cardiopulmonary Function ◽

Muscle Adaptations ◽

Selection For ◽

Seven Generations

Previous studies found that selection for endurance running in untrained rats produced distinct high (HCR) and low (LCR) capacity runners. Furthermore, despite weighing 14% less, 7th generation HCR rats achieved the same absolute maximal oxygen consumption (V̇o2max) as LCR due to muscle adaptations that improved oxygen extraction and use. However, there were no differences in cardiopulmonary function after seven generations of selection. If selection for increased endurance capacity continued, we hypothesized that due to the serial nature of oxygen delivery enhanced cardiopulmonary function would be required. In the present study, generation 15 rats selected for high and low endurance running capacity showed differences in pulmonary function. HCR, now 25% lighter than LCR, reached a 12% higher absolute V̇o2max than LCR, P < 0.05 (49% higher V̇o2max/kg). Despite the 25% difference in body size, both lung volume (at 20 cmH2O airway pressure) and exercise diffusing capacity were similar in HCR and LCR. Lung volume of LCR lay on published mammalian allometrical relationships while that of HCR lay above that line. Alveolar ventilation at V̇o2max was 30% higher, P < 0.05 (78% higher, per kg), arterial Pco2 was 4.5 mmHg (17%) lower, P < 0.05, while total pulmonary vascular resistance was (insignificantly) 5% lower (30% lower, per kg) in HCR. The smaller mass of HCR animals was due mostly to a smaller body frame rather than to a lower fat mass. These findings show that by generation 15, lung size in smaller HCR rats is not reduced in concert with their smaller body size, but has remained similar to that of LCR, supporting the hypothesis that continued selection for increased endurance capacity requires relatively larger lungs, supporting greater ventilation, gas exchange, and pulmonary vascular conductance.

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Testing for Asymmetrical Gene Flow in aDrosophila melanogasterBody-Size Cline

Genetics ◽

10.1093/genetics/165.2.667 ◽

2003 ◽

Vol 165 (2) ◽

pp. 667-673 ◽

Cited By ~ 7

Author(s):

W Jason Kennington ◽

Julia Gockel ◽

Linda Partridge

Keyword(s):

Drosophila Melanogaster ◽

Gene Flow ◽

Body Size ◽

Genetic Parameter ◽

Good Evidence ◽

Microsatellite Data ◽

Eastern Australia ◽

The Difference ◽

Two Populations ◽

Private Alleles

AbstractAsymmetrical gene flow is an important, but rarely examined genetic parameter. Here, we develop a new method for detecting departures from symmetrical migration between two populations using microsatellite data that are based on the difference in the proportion of private alleles. Application of this approach to data collected from wild-caught Drosophila melanogaster along a latitudinal body-size cline in eastern Australia revealed that asymmetrical gene flow could be detected, but was uncommon, nonlocalized, and occurred in both directions. We also show that, in contrast to the findings of a previous study, there is good evidence to suggest that the cline experiences significant levels of gene flow between populations.

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Relationship between circadian period and body size in the tau-mutant golden hamster

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2013-0276 ◽

2014 ◽

Vol 92 (1) ◽

pp. 27-33

Author(s):

Roberto Refinetti

Keyword(s):

Body Size ◽

Single Gene ◽

Pleiotropic Effect ◽

Circadian Period ◽

Golden Syrian Hamster ◽

Casein Kinase 1 ◽

Reduced Body ◽

Short Period ◽

Casein Kinase 1 Epsilon ◽

Tau Mutation

The tau mutation in the golden (Syrian) hamster is a single gene mutation that drastically affects the speed of the circadian clock, in such a way that homozygous mutants have an endogenous circadian period of 20 h (compared with 24 h for wild-type hamsters). While studying the circadian system of tau-mutant hamsters during the past 25 years, several authors have noted an apparent relationship between circadian period and body size in these animals. This study, based on 181 hamsters from 24 litters, confirmed previous observations that a shorter circadian period is associated with smaller body size, documented a sex difference in this association, and evaluated several mechanisms that might explain the phenomenon (such as different organ sizes, body composition, and metabolic rate). The obtained evidence suggests that the reduced body size of short-period hamsters is likely a pleiotropic effect of the tau allele (an allele of the casein kinase 1 epsilon gene) rather than a consequence of the shortened circadian period.

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Effects of ova transfer on the birthcoats of lambs

The Journal of Agricultural Science ◽

10.1017/s002185960008761x ◽

1972 ◽

Vol 78 (1) ◽

pp. 1-6 ◽

Cited By ~ 9

Author(s):

Marca Burns

Keyword(s):

Growth Rate ◽

Meat Production ◽

Transfer Experiment ◽

Primary Follicle ◽

Skin Expansion ◽

Foetal Growth ◽

Short Period ◽

Selection For ◽

Almost All ◽

Size At Birth

SUMMARYBirthcoat samples from Lincoln and Welsh Mountain lambs born in an ova transfer experiment (Weiner & Slee, 1965) were examined to determine the fibre type arrays and any effect of ova transfer on manifestation of the prenatal check or the base (Dry, 1965).In the Lincoln breed arrays were Truncated Ravine or Truncated Valley thus showing central checking. Pre-curly tip fibres were mainly confined to central primary follicles. Post-natal medullation was plentiful, especially in peak curly-tips, but kemp was absent. In the Welsh lambs all identifiable arrays were either Plateau or Saddle, with the lateral primary fibres more checked than the centrals. Pre-curly tip fibres occupied almost all the primary follicles, with only a few curly-tips in primary laterals. Post-natal medullation was strongest in pre-curly tips and their successors.The effect of ova transfer was to decrease the manifestation of check in Lincoln-in-Welsh and increase it in Welsh-in-Lincoln, without affecting the base. Although this, in each case, changed the check of the lamb in the direction of that of the foster breed, it is suggested that this may not be due to any influence of maternal check on foetal check. The effect on pre-natal check may be due to foetal size, and in particular skin expansion, during a short period immediately following completion of primary follicle initiation. As compared to their respective controls, the Welsh transfer lambs had a higher S/P ratio at birth, whilst that of the transferred Lincolns was reduced.If increased prenatal fibre check is associated with increased foetal growth rate at the relevant period, it may also be correlated with increased lamb size at birth and therefore have been favoured in selection for meat production, at least in some breeds.

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Social modulation of oogenesis and egg-laying in Drosophila melanogaster

10.1101/2021.09.13.460109 ◽

2021 ◽

Author(s):

Bailly Tiphaine ◽

Philip Kohlmeier ◽

Rampal Etienne ◽

Bregje Wertheim ◽

Jean-Christophe Billeter

Keyword(s):

Drosophila Melanogaster ◽

Social Context ◽

Social Systems ◽

Fruit Fly ◽

Egg Laying ◽

Physiological Adaptation ◽

Group Members ◽

Selection For ◽

Underlying Mechanisms ◽

Gravid Females

Being part of a group facilitates cooperation between group members, but also creates competition for limited resources. This conundrum is problematic for gravid females who benefit from being in a group, but whose future offspring may struggle for access to nutrition in larger groups. Females should thus modulate their reproductive output depending on their social context. Although social-context dependent modulation of reproduction is documented in a broad range of species, its underlying mechanisms and functions are poorly understood. In the fruit fly Drosophila melanogaster, females actively attract conspecifics to lay eggs on the same resources, generating groups in which individuals may cooperate or compete. The tractability of the genetics of this species allows dissecting the mechanisms underlying physiological adaptation to their social context. Here, we show that females produce eggs increasingly faster as group size increases. By laying eggs faster in group than alone, females appear to reduce competition between offspring and increase their likelihood of survival. In addition, females in a group lay their eggs during the light phase of the day, while isolated females lay them during the night. We show that responses to the presence of others are determined by vision through the motion detection pathway and that flies from any sex, mating status or species can trigger these responses. The mechanisms of this modulation of egg-laying by group is connected to a lifting of the inhibition of light on oogenesis and egg-laying by stimulating hormonal pathways involving juvenile hormone. Because modulation of reproduction by social context is a hallmark of animals with higher levels of sociality, our findings represent a protosocial mechanism in a species considered solitary that may have been the target of selection for the evolution of more complex social systems.

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Metacarpals and manual phalanges

Hominin Postcranial Remains from Sterkfontein, South Africa, 1936-1995 ◽

10.1093/oso/9780197507667.003.0009 ◽

2020 ◽

pp. 106-143

Author(s):

Tracy L. Kivell ◽

Kelly R. Ostrofsky ◽

Brian G. Richmond ◽

Michelle S.M. Drapeau

Keyword(s):

Body Size ◽

South African ◽

Index Finger ◽

External Morphology ◽

Australopithecus Africanus ◽

Fossil Evidence ◽

Frequent Use ◽

Selection For ◽

Locomotor Behaviors ◽

Fossil Hominin

This chapter presents description and analysis of the metacarpals and manual phalanges from Sterkfontein. Although the morphology is generally similar across the sample where there are duplicates of the same element, there are differences in size that are quite remarkable within the context of all South African hominins. Some very large specimens suggest the presence of individuals at Sterkfontein with much larger hands, and presumably larger body size, at Sterkfontein than those of A. sediba MH2, H. naledi and the Swartkrans hominins. Australopithecus africanus had human-like proportions, but this may be plesiomorphic within the hominoid clade. The potentially less mobile trapezium-Mc1 joint, absence of a fully developed palmar pulp on the distal thumb, more limited pronation of the index finger, and potentially more wedge-shaped trapezoid inferred from the preserved external morphology, is consistent with lower manipulative loading of the thumb than is typical of later Homo. As for other forelimb elements, moderately curved manual phalanges suggests a greater reliance on forelimb-dominated locomotor behaviors and perhaps selection for more frequent use of an arboreal environment in A. africanus than is found in A. afarensis. Thus, within this broader context, the Sterkfontein fossil hominin remains are not unusual. The Sterkfontein hand fossils suggest an overall manipulative and locomotor loading regime that was more similar to that of other South African australopiths and distinct from that of later Homo, but more refined functional interpretations require additional fossil evidence, particularly from associated hand skeletons

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FERTILITY OF BARLEY AUTOTETRAPLOIDS: I. FERTILITY IN SUCCESSIVE GENERATIONS OF FOUR AUTOTETRAPLOID BARLEY VARIETIES AND THE EFFECT OF SELECTION FOR FERTILITY IN THE O.A.C. 21 AUTOTETRAPLOID

Canadian Journal of Plant Science ◽

10.4141/cjps59-016 ◽

1959 ◽

Vol 39 (1) ◽

pp. 98-107 ◽

Cited By ~ 3

Author(s):

E. Reinbergs ◽

L. H. Shebeski

Keyword(s):

Promising Method ◽

Low Fertility ◽

Fertility Level ◽

Seed Setting ◽

The Mean ◽

Selection For ◽

Successive Generations ◽

Subsequent Selection

The differences in fertility of four colchicine-induced autotetraploid barley varieties (Brant, Montcalm, O.A.C. 21 and York) were determined and compared in four successive generations following the induction of tetraploidy. Despite a wide fertility range within each autotetraploid, the varieties tested varied considerably in their mean per cent fertility. Within each variety the mean per cent fertility remained relatively constant from generation to generation. The Montcalm tetraploid had the lowest mean fertility, fluctuating from generation to generation within a range of 6.0 to 10.1 per cent. The O.A.C. 21 tetraploid had the highest mean fertility, fluctuating within a range of 40.0 to 51.3 per cent.Significant differences in fertility of the four autotetraploid varieties were interpreted as indicating that seed-setting ability may be genetically controlled and, therefore, hybridization and subsequent selection could be a promising method for increasing fertility.Continuous selection for either high or low fertility from the C1 to C4 generation did not change the mean per cent fertility level in the O.A.C. 21 tetraploid.

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