Offspring sex ratio response to host size in the parasitoid wasp Spalangia endius

1999 ◽  
Vol 46 (5) ◽  
pp. 325-332 ◽  
Author(s):  
M. E. Napoleon ◽  
B. H. King
Keyword(s):  
Sex Ratio ◽  
Parasitoid Wasp ◽  
Host Size ◽  
Offspring Sex Ratio ◽  
Spalangia Endius ◽  
Offspring Sex ◽  
Ratio Response

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 Offspring sex ratio shifts of the solitary parasitoid wasp, Trichopria drosophilae (Hymenoptera: Diapriidae), under local mate competition

2018 ◽  
Vol 29 (2) ◽  
pp. 97-104 ◽  
Author(s):  
Jing Li ◽  
Yu Wang ◽  
Cheng-Jie Zhu ◽  
Min Zhang ◽  
Hao-Yuan Hu
Keyword(s):  
Sex Ratio ◽  
Parasitoid Wasp ◽  
Female Offspring ◽  
Mate Competition ◽  
Offspring Sex Ratio ◽  
Pupal Parasitoid ◽  
Offspring Sex ◽  
Local Mate ◽  
Solitary Parasitoid ◽  
Single Foundress

Localmate competition (LMC) models predict a female-biased offspring sex ratio when a single foundress oviposits alone in a patch and an increasing proportion of sons with increasing foundress number. We tested whether the solitary pupal parasitoid, Trichopria drosophilae (Hymenoptera: Diapriidae), adjusted offspring sex ratio with foundress number when parasitizing Drosophila melanogaster pupae. Mean number of female offspring was higher than that of males, with a male proportion of 26 ± 16% when only one foundress oviposited. However, male proportion reached 58 ± 26%, 48 ± 22%, and 51 ± 19% in three-, five and seven-foundress cohorts. That the male proportion of offspring increased with foundress number is consistent with LMC models.

scholarly journals Age-Dependent Constraints of Sex Allocation in a Parasitoid Wasp

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
Takatoshi Ueno
Keyword(s):  
Sex Ratio ◽  
Sex Ratios ◽  
Parasitoid Wasp ◽  
Maternal Control ◽  
Offspring Sex Ratio ◽  
Female Age ◽  
Physiological Constraints ◽  
Offspring Sex ◽  
Age Dependent ◽  
Control Failure

The offspring sex ratios of parasitoid wasps often depend on the age of ovipositing females. Physiological constraints such as sperm depletion and senescence are a likely cause. Also, maternal control in response to female age may be an alternative explanation. Here valvifer or abdominal tip movements were used to assess whether age-dependent sex ratio was due to physiological constraints or maternal control with an ichneumonid wasp,Pimpla nipponica; the offspring sex ratio at the time of wasp emergence was compared with the sex ratio predicted from abdominal tip movements. When the female was relatively young, there was little difference between the sex ratios examined. However, as the age of the females increased, the realized offspring sex ratio at wasp emergence was more male-biased than the sex ratio predicted at the time of oviposition. Thus, there was an inconsistency between the sex ratios. Curiously, the predictions of continuous movements for male egg deposition were always perfect, regardless of maternal age; fertilization control failure was detected when the females had decided to lay female eggs. Thus, physiological constraints are a likely explanation for the inconsistency in relation to female age forP. nipponica.

Offspring sex ratio in moose Alces alces in relation to paternal age: an experiment

2004 ◽  
Vol 10 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Bernt-Erik Sæther ◽  
Erling J. Solberg ◽  
Morten Heim ◽  
John E. Stacy ◽  
Kjetill S. Jakobsen ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Alces Alces ◽  
Paternal Age ◽  
Offspring Sex Ratio ◽  
Offspring Sex
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