Fitness-related offspring sex allocation ofAnastatus disparis, a gypsy moth egg parasitoid, on different-sized host species

2017 ◽  
Vol 163 (3) ◽  
pp. 281-286 ◽  
Author(s):  
Peng-Cheng Liu ◽  
Jin Men ◽  
Bin Zhao ◽  
Jian-Rong Wei
Keyword(s):  
Gypsy Moth ◽  
Host Species ◽  
Sex Allocation ◽  
Egg Parasitoid ◽  
Offspring Sex

scholarly journals Host and symbiont genetic contributions to fitness in a Trichogramma–Wolbachia symbiosis

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4655 ◽  
Author(s):  
James E. Russell ◽  
Leonard Nunney ◽  
Michael Saum ◽  
Richard Stouthamer
Keyword(s):  
Host Species ◽  
Low Frequency ◽  
Female Offspring ◽  
Egg Parasitoid ◽  
Relative Influence ◽  
Offspring Sex Ratio ◽  
Offspring Production ◽  
Evolutionary Conflict ◽  
Offspring Sex ◽  
Parthenogenetic Reproduction

The fitness effects associated with Wolbachia infection have wide-ranging ecological and evolutionary consequences for host species. How these effects are modulated by the relative influence of host and Wolbachia genomes has been described as a balancing act of genomic cooperation and conflict. For vertically transmitted symbionts, like cytoplasmic Wolbachia, concordant host–symbiont fitness interests would seem to select for genomic cooperation. However, Wolbachia’s ability to manipulate host reproductive systems and distort offspring sex ratios presents an evolutionary conflict of interest with infected hosts. In the parthenogenesis-inducing (PI) form of Wolbachia found in many haplodiploid insects, Wolbachia fitness is realized through females and is enhanced by their feminization of male embryos and subsequent parthenogenetic reproduction. In contrast, as long as Wolbachia is not fixed in a population and sexual reproduction persists, fitness for the host species is realized through both male and female offspring production. How these cooperating and competing interests interact and the relative influence of host and Wolbachia genomes were investigated in the egg parasitoid Trichogramma kaykai, where Wolbachia infection has remained at a low frequency in the field. A factorial design in which laboratory cultures of Wolbachia-infected T. kaykai were cured and re-infected with alternative Wolbachia strains was used to determine the relative influence of host and Wolbachia genomes on host fitness values. Our results suggest fitness variation is largely a function of host genetic background, except in the case of offspring sex ratio where a significant interaction between host and Wolbachia genomes was found. We also find a significant effect associated with the horizontal transfer of Wolbachia strains, which we discuss in terms of the potential for coadaptation in PI-Wolbachia symbioses.

scholarly journals Parental host species affects behavior and parasitism by the pentatomid egg parasitoid, Trissolcus japonicus (Hymenoptera: Scelionidae)

2020 ◽  
Vol 149 ◽  
pp. 104324 ◽  
Author(s):  
Sean M. Boyle ◽  
Donald C. Weber ◽  
Judith Hough-Goldstein ◽  
Kim A. Hoelmer
Keyword(s):  
Host Species ◽  
Egg Parasitoid ◽  
Trissolcus Japonicus

scholarly journals Sperm sex ratio adjustment in a mammal: perceived male competition leads to elevated proportions of female-producing sperm

2020 ◽  
Vol 16 (6) ◽  
pp. 20190929
Author(s):  
Renée C. Firman ◽  
Jamie N. Tedeschi ◽  
Francisco Garcia-Gonzalez
Keyword(s):  
Sex Ratio ◽  
Sex Allocation ◽  
Sex Ratios ◽  
Female Offspring ◽  
Male Competition ◽  
Offspring Sex ◽  
Sex Ratio Adjustment ◽  
Adaptive Adjustment ◽  
Male House

Mammal sex allocation research has focused almost exclusively on maternal traits, but it is now apparent that fathers can also influence offspring sex ratios. Parents that produce female offspring under conditions of intense male–male competition can benefit with greater assurance of maximized grand-parentage. Adaptive adjustment in the sperm sex ratio, for example with an increase in the production of X-chromosome bearing sperm (CBS), is one potential paternal mechanism for achieving female-biased sex ratios. Here, we tested this mechanistic hypothesis by varying the risk of male–male competition that male house mice perceived during development, and quantifying sperm sex ratios at sexual maturity. Our analyses revealed that males exposed to a competitive ‘risk’ produced lower proportions of Y-CBS compared to males that matured under ‘no risk’ of competition. We also explored whether testosterone production was linked to sperm sex ratio variation, but found no evidence to support this. We discuss our findings in relation to the adaptive value of sperm sex ratio adjustments and the role of steroid hormones in socially induced sex allocation.

scholarly journals Sex allocation theory reveals a hidden cost of neonicotinoid exposure in a parasitoid wasp

2015 ◽  
Vol 282 (1807) ◽  
pp. 20150389 ◽  
Author(s):  
Penelope R. Whitehorn ◽  
Nicola Cook ◽  
Charlotte V. Blackburn ◽  
Sophie M. Gill ◽  
Jade Green ◽  
...  
Keyword(s):  
Sex Allocation ◽  
Evolutionary Ecology ◽  
Parasitoid Wasp ◽  
Reproductive Behaviour ◽  
Fitness Costs ◽  
Offspring Sex ◽  
Hidden Cost ◽  
Sex Allocation Theory ◽  
First Time ◽  
Fecundity Reduction

Sex allocation theory has proved to be one the most successful theories in evolutionary ecology. However, its role in more applied aspects of ecology has been limited. Here we show how sex allocation theory helps uncover an otherwise hidden cost of neonicotinoid exposure in the parasitoid wasp Nasonia vitripennis . Female N. vitripennis allocate the sex of their offspring in line with Local Mate Competition (LMC) theory. Neonicotinoids are an economically important class of insecticides, but their deployment remains controversial, with evidence linking them to the decline of beneficial species. We demonstrate for the first time to our knowledge, that neonicotinoids disrupt the crucial reproductive behaviour of facultative sex allocation at sub-lethal, field-relevant doses in N. vitripennis . The quantitative predictions we can make from LMC theory show that females exposed to neonicotinoids are less able to allocate sex optimally and that this failure imposes a significant fitness cost. Our work highlights that understanding the ecological consequences of neonicotinoid deployment requires not just measures of mortality or even fecundity reduction among non-target species, but also measures that capture broader fitness costs, in this case offspring sex allocation. Our work also highlights new avenues for exploring how females obtain information when allocating sex under LMC.

Host size-dependent sex allocation behaviour in a parasitoid: implications forCatolaccus grandis(Hymenoptera: Pteromalidae) mass rearing programmes

1998 ◽  
Vol 88 (1) ◽  
pp. 37-45 ◽  
Author(s):  
K.M. Heinz
Keyword(s):  
Biological Control ◽  
Sex Ratio ◽  
Sex Allocation ◽  
Sex Ratios ◽  
Boll Weevil ◽  
Mass Rearing ◽  
Host Size ◽  
Offspring Sex Ratio ◽  
Offspring Sex ◽  
Control Programmes

AbstractAn often encountered problem associated with augmentative and inundative biological control programmes is the high cost of producing sufficient numbers of natural enemies necessary to suppress pest populations within the time constraints imposed by ephemeral agroecosystems. In many arrhenotokous parasitoids, overproduction of males in mass-rearing cultures inflates costs (per female) and thus limits the economic feasibility of these biological control programmes. Within the context of existing production technologies, experiments were conducted to determine if the sex ratio ofCatolaccus grandis(Burks), an ectoparasitoid of the boll weevilAnthonomous grandisBoheman, varied as a function of boll weevil larval size. Results from natural and manipulative experiments demonstrate the following behavioural characteristics associated with C.grandissex allocation behaviour: (i) femaleC. grandisoffspring are produced on large size hosts and male offspring are produced on small hosts; (ii) whether a host is considered large or small depends upon the overall distribution of host sizes encountered by a female parasitoid; and (iii) female parasitoids exhibit a greater rate of increase in body size with host size than do male parasitoids. The observed patterns cannot be explained by sex-specific mortality of immature parasitoids developing on the different host size categories. In subsequent experiments, laboratory cultures ofC. grandisexposed daily to successively larger sizes ofA. grandislarvae produced successively greater female biased offspring sex ratios, cultures exposed daily to successively smaller sizes of host larvae produced successively greater male biased offspring sex ratios, and cultures exposed daily to equivalent host size distributions over time maintained a uniform offspring sex ratio. By increasing the average size ofA. grandislarval hosts exposed toC. grandisby 2.5 mg per day in mass rearing cultures, the percentage of male progeny can be reduced from 33% to 23% over a period of four consecutive exposure days.

scholarly journals Evidence of capacitation in the parasitoid wasp, Nasonia vitripennis and its potential role in sex allocation

2019 ◽  
Author(s):  
A.R.C. Jones ◽  
E.B. Mallon
Keyword(s):  
Alternative Splicing ◽  
Sperm Motility ◽  
Sex Allocation ◽  
Potential Role ◽  
Parasitoid Wasp ◽  
Published Data ◽  
Allocation Of Resources ◽  
Nasonia Vitripennis ◽  
Offspring Sex ◽  
Show Evidence

AbstractThe allocation of resources to the production of one sex or another has been observed in a large variety of animals. Its theoretical basis allows accurate predictions of offspring sex ratios in many species, but the mechanisms by which sex allocation is controlled are poorly understood. Using previously published data we investigated if alternative splicing, combined with differential expression, were involved with sex allocation in the parasitoid wasp, Nasonia vitripennis. We found that sex allocation is not controlled by alternative splicing but changes in gene expression, that were identified to be involved with oviposition, were shown to be similar to those involved in sperm motility, and capacitation. Genes involved in Cholesterol efflux, a key component of capacitation, along with calcium transport, trypsin and MAPKinase activity were regulated in ovipositing wasps. The results show evidence for regulation of sperm motility and of capacitation in an insect which, in the context of the physiology of the N. vitripennis spermatheca, could be important for sex allocation.

scholarly journals Breeding ecology and bias in offspring sex ratio in little grassbirds (Megalurus gramineus)

2003 ◽  
Vol 51 (5) ◽  
pp. 505 ◽  
Author(s):  
Rebecca R. McIntosh ◽  
Romke Kats ◽  
Mathew Berg ◽  
Jan Komdeur ◽  
Mark A. Elgar
Keyword(s):  
Sex Ratio ◽  
Breeding Season ◽  
Salt Marshes ◽  
Sex Allocation ◽  
Breeding Ecology ◽  
Offspring Sex Ratio ◽  
Reed Beds ◽  
Primary Sex Ratio ◽  
Sex Ratio Bias ◽  
Offspring Sex

Little grassbirds (Megalurus gramineus) are small, sexually monomorphic passerines that live in reed beds, lignum swamps and salt marshes in southern Australia. The breeding biology and patterns of sex allocation of the little grassbird were investigated over a single breeding season. Our observations of this species in the Edithvale Wetland Reserve revealed a highly male-biased population sex ratio, with some breeding territories containing several additional males. Nevertheless, there was little compelling evidence that little grassbirds breed cooperatively. The growth rates of male and female nestlings were similar and, as predicted by theory, there was no overall primary sex ratio bias. However, the primary sex ratio was female-biased early in the breeding season and became increasingly male-biased later in the breeding season.

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