EFFECTS OF MATERNAL DENSITY AND AGE ON THE DAILY FECUNDITY AND OFFSPRING SEX RATIO IN TETRANYCHUS URTICAE KOCH

1993 ◽  
Vol 125 (3) ◽  
pp. 633-635 ◽  
Author(s):  
S.Y. Li ◽  
R. Harmsen
Keyword(s):  
Sex Ratio ◽  
Tetranychus Urticae ◽  
Female Offspring ◽  
Spider Mites ◽  
Offspring Sex Ratio ◽  
Factors Affecting ◽  
Offspring Sex ◽  
Biased Sex Ratio ◽  
Two Spotted Spider Mite ◽  
Tetranychus Urticae Koch

The two-spotted spider mite, Tetranychus urticae Koch, is an arrhenotokous species (Helle and Bolland 1967). Mated females produce both male and female offspring; unmated females produce only sons. Although there is no “normal” sex ratio for spider mites, a ratio of one male to approximately three females is often found in many tetranychid species (Wrensch 1985). The exact mechanism of the female-biased sex ratio is not fully understood, but previous studies have demonstrated several factors affecting the sex ratio in spider mites. In this report, we analyze the effects of maternal density, age, and the interaction between these factors on female daily fecundity and offspring sex ratio in T. urticae.

Adjustment of fecundity and sex ratio in response to social environments in a haplodiploid mite

2022 ◽  
Author(s):  
Nuwan Weerawansha ◽  
Qiao Wang ◽  
Xiong Zhao He
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Population Size ◽  
Local Population ◽  
Female Offspring ◽  
Social Environments ◽  
Positive Interaction ◽  
Offspring Sex Ratio ◽  
Offspring Sex ◽  
Large Populations

Animals can adjust reproductive strategies in favour of corporation or competition in response to local population size and density, the two key factors of social environments. However, previous studies usually focus on either population size or density but ignore their interactions. Using a haplodiploid spider mite, Tetranychus ludeni Zacher, we carried out a factorial experiment in the laboratory to examine how ovipositing females adjust their fecundity and offspring sex ratio during their early reproductive life under various population size and density. We reveal that females laid significantly more eggs with increasing population size and significantly fewer eggs with increasing population density. This suggests that large populations favour cooperation between individuals and dense populations increase competition. We demonstrate a significant negative interaction of population size and density that resulted in significantly fewer eggs laid in the large and dense populations. Furthermore, we show that females significantly skewed the offspring sex ratio towards female-biased in small populations to reduce the local mate competition among their sons. However, population density incurred no significant impact on offspring sex ratio, while the significant positive interaction of population size and density significantly increased the proportion of female offspring in the large and dense populations, which will minimise food or space competition as females usually disperse after mating at crowded conditions. These results also suggest that population density affecting sex allocation in T. ludeni is intercorrelated with population size. This study provides evidence that animals can manipulate their reproductive output and adjust offspring sex ratio in response to various social environments, and the interactions of different socio-environmental factors may play significant roles.

scholarly journals Maternal Diet and Other Factors Affecting Offspring Sex Ratio: A Review

2004 ◽  
Vol 71 (4) ◽  
pp. 1063-1070 ◽  
Author(s):  
Cheryl S. Rosenfeld ◽  
R. Michael Roberts
Keyword(s):  
Sex Ratio ◽  
Maternal Diet ◽  
Offspring Sex Ratio ◽  
Factors Affecting ◽  
Offspring Sex

Skewed Sex-Ratio, Monogeny, and Maternal Sex Determination in Two Geographical Populations of Asellus Aquaticus (L., 1758) (Isopoda)

Crustaceana ◽  
1996 ◽  
Vol 69 (4) ◽  
pp. 455-475 ◽  
Author(s):  
Giovanna Vitagliano ◽  
Enzo Marchetti ◽  
Eleonora Vitagliano
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
The Other ◽  
Italian Population ◽  
Asellus Aquaticus ◽  
Offspring Sex Ratio ◽  
New Born ◽  
Offspring Sex ◽  
Geographical Populations ◽  
Biased Sex Ratio

AbstractFor the great majority of the amphipods and isopods a biased sex ratio is attributed to photoperiod or to micro-organisms present in the cytoplasm of the oocytes. Since monogenous pairs are found in orders and species phylogenetically very far from each other, in order to try and clarify this phenomenon, two geographical populations of Asellus aquaticus (Isopoda) were collected in the Netherlands and in Italy, where the duration of the cold season and the photoperiods are very different. From these parental (P) populations, 200 females and 200 males per population were randomly subsampled and bred under standard conditions of temperature and nutrition. One half of each P generation was subjected to 18 hours light per day, the other to 14 hours light per day. New-born of each pair (laboratory F1) were grown up to differentiation of external sexual characters under the same photoperiod experienced by the parents. Also, hybrid F1 generation, born from mating between the two populations, was conceived in both photoperiods, but, after birth, one half of the new-born was maintained in the same photoperiod in which they were conceived, the other half was grown under the other photoperiod. No significant difference between the sex ratios was found in the two photoperiods, neither between Italian nor between Dutch Asellus. The sex ratio of Dutch F1 is female biased, while it is male biased in Italian Asellus. The female- or male-biased sex ratio can be ascribed to the high proportion of monogenous pairs in which offspring sex ratio is significantly biased towards females (in the Dutch population) and/or in which offspring sex ratio is significantly biased towards males (in the Italian population). On the basis of these results we can rule out the influence of photoperiod in sex determination for this species. The results shown by the hybrids suggest some form of maternal inheritance. In fact, the hybrids' sex ratio as indeed the frequency of pairs breeding one sex alone, was skewed towards the same sex for which the maternal population showed a bias. We therefore consider the possibility of sex determination associated with a cytoplasmic factor (a mitochondrial DNA?), which would inactivate only one of the two sets of genes governing sex determination.

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.

Repellency and Repulsiveness of Selected Agrichemicals to the Two-Spotted Spider Mite (Tetranychus urticae) on Grape Foliage

2005 ◽  
Vol 6 (1) ◽  
pp. 1 ◽  
Author(s):  
Douglas B. Walsh ◽  
Gary G. Grove
Keyword(s):  
Bacillus Thuringiensis ◽  
Tetranychus Urticae ◽  
Spider Mite ◽  
Spatial Dynamics ◽  
Spider Mites ◽  
Leaf Disk ◽  
Plant Canopies ◽  
Two Spotted Spider Mite ◽  
Tetranychus Urticae Koch ◽  
Spray Adjuvants

Leaf disk and whole leaf bioassays were conducted to evaluate the repellency and repulsiveness of selected fungicides, insecticides, spray adjuvants, and petroleum-derived spray oils (PDSO) to the two-spotted spider mite, Tetranychus Urticae Koch (Acari: Tetranychidae). Compounds were evaluated for their ability to stimulate the movement of T. urticae from treated to nontreated grape tissue (repellency) and to inhibit their movement from untreated to treated tissue (repulsiveness). All insecticides other than Bacillus thuringiensis and some fungicides were highly repellent. Several insecticides and fungicides, and all spray adjuvants, were highly repulsive. We conclude that many agrichemicals are irritating to two-spotted spider mites and may impact their spatial dynamics within plant canopies. Accepted for publication 7 November 2005. Published 28 December 2005.

scholarly journals Maternal corticosterone exposure has transgenerational effects on grand-offspring

2016 ◽  
Vol 12 (11) ◽  
pp. 20160627 ◽  
Author(s):  
Nicola Khan ◽  
Richard A. Peters ◽  
Emily Richardson ◽  
Kylie A. Robert
Keyword(s):  
Reproductive Success ◽  
Sex Ratio ◽  
Hatching Success ◽  
First Record ◽  
Female Offspring ◽  
Adaptive Mechanism ◽  
Offspring Sex Ratio ◽  
Sex Ratio Bias ◽  
Offspring Sex ◽  
Unstable Environment

The hormone fluctuations that an animal experiences during ovulation can have lifelong effects on developing offspring. These hormones may act as an adaptive mechanism, allowing offspring to be ‘pre-programmed’ to survive in an unstable environment. Here, we used a transgenerational approach to examine the effects of elevated maternal corticosterone (CORT) on the future reproductive success of female offspring. We show that female zebra finches ( Taeniopygia guttata ) exposed to embryonic CORT produce daughters that have equal reproductive success (clutch sizes, fertility, hatching success) compared with the daughters produced from untreated mothers, but their offspring had accelerated post-hatching growth rates and were significantly heavier by nutritional independence. Although there was no significant effect on primary offspring sex ratio, females from CORT-treated mothers produced significantly female-biased clutches by nutritional independence. To the best of our knowledge, this is the first record of a transgenerational sex ratio bias in response to elevated maternal CORT in any avian species.

scholarly journals Transgenerational cues about local mate competition affect offspring sex ratios in the spider mite Tetranychus urticae

2017 ◽  
Author(s):  
Alison B. Duncan ◽  
Cassandra Marinosci ◽  
Céline Devaux ◽  
Sophie Lefèvre ◽  
Sara Magalhães ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Tetranychus Urticae ◽  
Sex Allocation ◽  
Spider Mite ◽  
Sex Ratios ◽  
Mate Competition ◽  
Maternal Environment ◽  
Offspring Sex Ratio ◽  
Offspring Sex ◽  
Local Mate

ABSTRACTThis preprint has been reviewed and recommended by Peer Community In Evolutionary Biology (https://doi.org/10.24072/pci.evolbiol.100051). In structured populations, competition for mates between closely related males, termed Local Mate Competition (LMC), is expected to select for female-biased offspring sex ratios. However, the cues underlying sex allocation decisions remain poorly studied. Here, we test for several cues in the spider mite Tetranychus urticae, a species that was previously found to adjust the sex ratio of its offspring in response to the number of females within the local population, i.e. a patch. We here investigate whether the offspring sex ratio of T. urticae females changes in response to 1) the current number of females in the same patch, 2) the number of females in the patches of their mothers and 3) their relatedness to their mate. Single females on patches produced similar sex ratios to those of groups of 15 females; their mothers had been in identical conditions of panmixia. The offspring sex ratios of females mated with their brother did not differ from those of females mated with an unrelated male. Females however produced a more female-biased offspring sex ratio if their mothers were alone on a patch compared to 15 other females. Thus, maternal environment is used as a cue for the sex allocation of daughters. We discuss the conditions under which the maternal environment may be a reliable predictor of LMC experienced by grand-sons.

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