scholarly journals Wolbachia promote successful sex with siblings

2019 ◽  
Author(s):  
Zeynab Bagheri ◽  
Ali Asghar Talebi ◽  
Sassan Asgari ◽  
Mohammad Mehrabadi

AbstractWolbachia are intracellular α-proteobacteria that have a wide distribution among various arthropods and nematodes. They affect the host reproduction favoring their maternal transmission, which sets up a potential conflict in inbreeding situations when the host avoids sexual reproduction preventing inbreeding depression, while Wolbachia pushes it. In this study, we used the wasp Habrobracon hebetor to test the hypothesis that Wolbachia modulate inbreeding avoidance behaviour and promote sib mating. To test this, we first cured wasps of Wolbachia using tetracycline treatment and produced infected and uninfected isolines. Then, we paired the uninfected and infected females with sibling (inbred) and non-sibling (outbred) males in choice and non-choice experiments. Our results showed no obvious precopulatory inbreeding avoidance in this wasp as brother-sister mating rates (in both choice and nonchoice experiments) were not significantly different form non-sibling pairs, regardless of Wolbachia infection. However, our results indicated that H. hebetor shows a strong postcopulatory inbreeding avoidance behaviour that results in a low fertilization rate of uninfected siblings and therefore high rate of production of male progeny was obtained. We observed higher rates of fertilization success in the Wolbachia-infected lines that resulted in significantly higher female progeny production compared to the uninfected sib mates. Since diploid females are the result of successful fertilization due to haplodiploidy sex determination system in this insect, our results indicate that Wolbachia promoted fertile sib mating in H. hebetor. Interestingly, the rate of adult emergence in the progeny of Wolbachia-infected sib mates were almost similar to the non-sib mate crosses and significantly more than those observed in the uninfected sib mate crosses. We support the idea that Wolbachia modulate inbreeding avoidance and promote sib mating and also mitigate inbreeding depression. The wasp Habrobracon hebetor siblings infected with Wolbachia show higher rates of fertilization success and higher adult emergence rates compared to the uninfected sib mates. By promoting successful sex with siblings and increasing the probability of female progeny, Wolbachia enhance their transmission to the next generation and also mitigate inbreeding depression. This is an undescribed effect of Wolbachia (symbiont) on the host reproduction.

Evolution ◽  
2015 ◽  
Vol 69 (11) ◽  
pp. 2846-2861 ◽  
Author(s):  
Jane M. Reid ◽  
Peter Arcese ◽  
Greta Bocedi ◽  
A. Bradley Duthie ◽  
Matthew E. Wolak ◽  
...  

Heredity ◽  
2016 ◽  
Vol 117 (5) ◽  
pp. 326-335 ◽  
Author(s):  
K E Harper ◽  
R K Bagley ◽  
K L Thompson ◽  
C R Linnen

1983 ◽  
Vol 6 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Pierre L. van den Berghe

AbstractMuch clinical and ethnographic evidence suggests that humans, like many other organisms, are selected to avoid close inbreeding because of the fitness costs of inbreeding depression. The proximate mechanism of human inbreeding avoidance seems to be precultural, and to involve the interaction of genetic predispositions and environmental conditions. As first suggested by E. Westermarck, and supported by evidence from Israeli kibbutzim, Chinese sim-pua marriage, and much convergent ethnographic and clinical evidence, humans negatively imprint on intimate associates during a critical period of early childhood (between ages 2 and 6).There is also much evidence that, like other social animals, humans do not seek to maximize outbreeding, but rather to maintain an optimal balance between outbreeding and inbreeding.Closeinbreeding reduces fitness through inbreeding depression, butsomeinbreeding brings the benefits of nepotism. For simple, stateless, horticultural societies, the optimal balance seems to be achieved by a combination of precultural inbreeding avoidance of relatives with anr≤·25 and cultural rules of preferential marriage with kin withr≥·25. Adjustment of the coefficient of inbreeding to other ecological settings seems to be largely cultural. An interactive model of “culture in nature” is presented, in which culture is seen as coevolving with genes to produce the maxiniization of individual inclusive fitness.


1967 ◽  
Vol 15 (2) ◽  
pp. 303 ◽  
Author(s):  
MA Bateman ◽  
FJ Sonleitner

The ecology of a natural population of Dacus tryoni is being studied at an orchard near Sydney, N.S.W. Changes in numbers observed during a single year are described and discussed. Estimates of pupal numbers were based on the weekly total pupal production of a random sample of the fruit trees in the orchard. Parameters of the adult population were measured by means of mark-recapture sampling and analysed by means of three mathematical models. Discrepancies between some of the estimates of numbers given by these models are explained by extensive adult emergence at those times, and the lower survival factors of the young adults. Evidence for the random sampling of adults is presented. The decline of the population towards the end of the season was brought about mainly by (1) high pupal mortality, (2) cessation of pupal production due to diminution and disappearance of larval food, (3) a marked decline in the number of gravid females, apparently in response to diminishing oviposition sites, and (4) a high rate of loss of young adults, presumably by emigration. There was no evidence of overcrowding.


1966 ◽  
Vol 8 (2) ◽  
pp. 261-266 ◽  
Author(s):  
J. M. Doney

Four Scottish Blackface rams were mated with a group of their own daughters and a similar number of non-related ewes. The matings were made in three successive years. All ewes were maintained under normal hill conditions. Female progeny from the matings entered the ewe flock unculled. Records of birth type, birth weight, fleece and live-weights throughout life were obtained.Inbred lambs had lower mean values for all measured characters than did their non-inbred half-sibs and there was a greater number of apparently barren ewes amongst the flock ewes which were expected to produce inbred lambs. The inbred progeny, also maintained in the normal hill flock, showed a higher incidence of barrenness and lower lamb survival rates at all ages than did their non-inbred contemporaries in the same environment. In the final year of the observations, when the standard of nutrition during late pregnancy was raised, the neo-natal mortality rate in both groups was reduced.


2010 ◽  
Vol 277 (1699) ◽  
pp. 3483-3491 ◽  
Author(s):  
Łukasz Michalczyk ◽  
Oliver Y. Martin ◽  
Anna L. Millard ◽  
Brent C. Emerson ◽  
Matthew J. G. Gage

As populations decline to levels where reproduction among close genetic relatives becomes more probable, subsequent increases in homozygous recessive deleterious expression and/or loss of heterozygote advantage can lead to inbreeding depression. Here, we measure how inbreeding across replicate lines of the flour beetle Tribolium castaneum impacts on male reproductive fitness in the absence or presence of male–male competition. Effects on male evolution from mating pattern were removed by enforcing monogamous mating throughout. After inbreeding across eight generations, we found that male fertility in the absence of competition was unaffected. However, we found significant inbreeding depression of sperm competitiveness: non-inbred males won 57 per cent of fertilizations in competition, while inbred equivalents only sired 42 per cent. We also found that the P 2 ‘offence’ role in sperm competition was significantly more depressed under inbreeding than sperm ‘defence’ (P 1 ). Mating behaviour did not explain these differences, and there was no difference in the viability of offspring sired by inbred or non-inbred males. Sperm length variation was significantly greater in the ejaculates of inbred males. Our results show that male ability to achieve normal fertilization success was not depressed under strong inbreeding, but that inbreeding depression in these traits occurred when conditions of sperm competition were generated.


Ethology ◽  
2010 ◽  
Vol 116 (5) ◽  
pp. 448-457 ◽  
Author(s):  
Ashley M. Johnson ◽  
Grace Chappell ◽  
Anna C. Price ◽  
F. Helen Rodd ◽  
Robert Olendorf ◽  
...  

1967 ◽  
Vol 10 (1) ◽  
pp. 73-80 ◽  
Author(s):  
J. C. McCarthy

Twenty-four lines were bred from a base population of outbred Q mice by continued full-sib mating. Inbreeding depression in litter size at birth was observed. This decline in litter size was analysed in terms of ovulation rate, the incidence of preimplantation mortality and the incidence of postimplantation mortality. Pregnant females were dissected at 17½ days' gestation and the numbers of corpora lutea, or eggs, and of live and dead embryos were counted. Matings were arranged so that separate estimates of the effects of inbreeding in the mother and in the litter on the components of litter size could be obtained.In the first generation of inbreeding when the inbreeding coefficient of the litter was raised from 0 to 25% decline in litter size was attributable to an increased incidence of preimplantation mortality.In the second and fourth generations decline in litter size was attributable to (1) a reduction in the number of eggs ovulated by the inbred mothers, (2) an increased incidence of preimplantation mortality which resulted from inbreeding in the mother. No evidence of significant effects on mortality of inbreeding in the litter was obtained in the later generation of inbreeding.These findings are discussed in the context of previous work on the effects of inbreeding and crossing on litter size and its components in mice and pigs.


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