Copulation, egg production and sex ratio inCydnodromella negevi andTyphlodromus athiasae (Acari, Phytoseiidae)

1997 ◽  
Vol 70 (2) ◽  
pp. 34-36 ◽  
Author(s):  
F. M. Momen
Keyword(s):  
Sex Ratio ◽  
Egg Production

The Life-History of Badumna-Candida (Araneae, Amaurobioidea)

1993 ◽  
Vol 41 (5) ◽  
pp. 441 ◽  
Author(s):  
MF Downes
Keyword(s):  
Sex Ratio ◽  
Egg Production ◽  
Production Cycle ◽  
Social Spider ◽  
Social Spiders ◽  
Primary Sex Ratio ◽  
The Social ◽  
The Status ◽  
History Of ◽  
Changes Over Time

A two-year study of the social spider Badumna candida at Townsville, Queensland, provided information on colony size and changes over time, maturation synchrony, temperature effects on development, sex ratio, dispersal, colony foundation, fecundity and oviposition. Key findings were that B. candida outbred, had an iteroparous egg-production cycle between March and October, had an even primary sex ratio and achieved maturation synchrony by retarding the development of males, which matured faster than females at constant temperature. There was no overlap of generations, the cohort of young from a nest founded by a solitary female in summer dispersing the following summer as subadults (females) or subadults and adults (males). These findings confirm the status of B. candida as a periodic-social spider (an annual outbreeder), in contrast to the few known permanent-social spider species whose generations overlap. Cannibalism, normally rare in social spiders, rose to 48% when spiders were reared at a high temperature. This may be evidence that volatile recognition pheromones suppress predatory instincts in social spiders.

When Less Is More: Sex Ratios for the Mass-Rearing of Anastrepha ludens (Diptera: Tephritidae)

2019 ◽  
Author(s):  
G I González-López ◽  
E Solís-Echeverría ◽  
F Díaz-Fleischer ◽  
D Pérez-Staples
Keyword(s):  
Sex Ratio ◽  
Egg Production ◽  
Sex Ratios ◽  
Pupal Stage ◽  
Mass Rearing ◽  
Anastrepha Ludens ◽  
Adult Density ◽  
Genetic Sexing ◽  
Male Harassment ◽  
Less Is More

Abstract Anastrepha ludens (Loew) is one of the most important pests of citrus and mango crops in Mexico. A method used to control this pest is the sterile insect technique, which consists in the mass production, irradiation, and release of insects in affected areas. The production of insects begins with the establishment of colonies to produce eggs, which must be highly fertile to ensure an adequate production of larvae. However, female fecundity and fertility can be affected by adult density and sex ratio, thus an optimal sex ratio in mass-rearing cages must be used. The genetic sexing strain of A. ludens (Tapachula-7) allows the identification of the sex at the pupal stage, making it possible to establish rearing cages with different sex ratios. We determined if different sex ratios have an effect on egg production. Two sex ratios (4♀: 1♂ and 1♀: 1♂) were compared. Fecundity, fertility and survival at different ages were also determined. Higher fertility and fecundity per female were observed at a ratio of 4:1. However, females with higher fecundity had reduced survival probabilities. In conclusion, maintaining colonies with a lower proportion of males in cages ensures a greater fecundity and fertility. Further research is necessary to understand whether results can be attributed to lower male harassment in cages.

scholarly journals Egg production of Baltic cod (Gadus morhua) in relation to variable sex ratio, maturity, and fecundity

2002 ◽  
Vol 59 (12) ◽  
pp. 1908-1920 ◽  
Author(s):  
Gerd Kraus ◽  
Jonna Tomkiewicz ◽  
Friedrich W Köster
Keyword(s):  
Sex Ratio ◽  
Egg Production ◽  
Gadus Morhua ◽  
Reproductive Potential ◽  
Relative Fecundity ◽  
Spawning Stock ◽  
Class Strength ◽  
The Difference ◽  
Eastern Baltic ◽  
Baltic Cod

Observed fluctuations in relative fecundity of Eastern Baltic cod (Gadus morhua L.) were related to food availability during the main feeding period and were used to develop a predictive model that explained 72% of the interannual variations in fecundity. Time series of sex ratios, maturity ogives, and relative fecundity were combined with mean weights-at-age and stock sizes from an analytical multispecies model to estimate the potential egg production (PEP). Relationships between PEP and independent estimates of realized daily and seasonal egg production from egg surveys were highly significant. The difference between estimates of potential and realized seasonal egg production was of a magnitude corresponding to the expected loss of eggs as a result of atresia, fertilization failure, and early egg mortality. The removal of interannual variability in sex ratio, maturity, and fecundity on estimates of PEP deteriorated the relationships in all three cases. PEP proved to be superior to spawning stock biomass as measure of the reproductive potential in a stock-recruitment relationship of Eastern Baltic cod. PEP in combination with the reproductive volume explained 61% of the variation in year-class strength at age 2.

Effects of Adult Sex Ratio and Stocking Rate on Viable Egg Production of Anopheles Albimanus (Diptera: Culicidae)1

1980 ◽  
Vol 17 (6) ◽  
pp. 563-566 ◽  
Author(s):  
Donald L. Bailey ◽  
Ronald E. Lowe ◽  
Joyce E. F. Fowler ◽  
Dana A. Focks
Keyword(s):  
Sex Ratio ◽  
Egg Production ◽  
Stocking Rate ◽  
Anopheles Albimanus ◽  
Adult Sex Ratio

COPULATION, EGG PRODUCTION AND SEX-RATIO IN PHYTOSEIULUS PERSIMILIS AND AMBLYSEIUS BIBENS (ACARI: PHYTOSEIIDAE)

1978 ◽  
Vol 24 (2) ◽  
pp. 145-153 ◽  
Author(s):  
G. G. M. SCHULTEN ◽  
R. C. M. ARENDONK ◽  
V. M. RUSSELL ◽  
F. A. ROORDA
Keyword(s):  
Sex Ratio ◽  
Egg Production ◽  
Phytoseiulus Persimilis

scholarly journals QUAIL EGG PRODUCTION WHEN SUPPLEMENTING THE DIET WITH BIOACTIVE SUBSTANCE

2021 ◽  
pp. 60-65
Author(s):  
P.I. Baryshnikov ◽  
◽  
L.V. Rastopshina ◽  
N.A. Novikov ◽  
V.M. Zhukov ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Egg Production ◽  
Economic Effect ◽  
Control Group ◽  
Optimal Dosage ◽  
Trial Group ◽  
Egg Weight ◽  
Bioactive Substance ◽  
Feed Costs ◽  
Experimental Findings

This paper discusses the experimental findings on lay-ing quails when their diets were supplemented with iodine and starch mixture. Five groups of 120 comparable quails bred in the Omsk Region were formed; the sex ratio was 1:4. The first group was the control; the birds were fed the main diet without the iodine supplement; the 2nd, 3rd, 4th and 5th groups were trial groups where the main diet was supplemented with iodine (potassium iodide) + starch (1:4) immediately before feeding. The dosages of the tested product in the trial groups were as following (in terms of iodine, mg per 100 g of feed): the 2nd group -0.05; 3rd -0.075; 4th -0.10; 5th -0.125. The experiment lasted for 180 days. Throughout the experiment, the largest number of eggs was obtained in the 3rd trial group -15240 eggs, more by 18.1% than in the control group (P ≥ 0.99). The laying quail day egg production in the 3rd trial group was 25.4 eggs, more by 13.0% than that in the control group. In the 2nd, 3rd, 4th, and 5th trial groups, the average egg weight was less than in the control, respectively, by 4.5; 7.1 and 8.0%. The number of produced eggs in the 3rd trial group was more than in the control group by 17.0% (P ≥ 0.95), and the intensity of egg production -by 10.0%. The feed costs were lower in the trial groups by 0.16-15.57% for the production of 10 eggs; and for the production of 1 kg of eggs in the 3rd and 4th trial groups -by 9.08 and 3.12% than in the control. The profitability in the 3rd trial group made 54.2%; that was by 1.59% higher than in the control group. The optimal dosage of iodine as much as 0.075 mg per 100 g of complete feed was determined which contrib-uted to obtaining a greater economic effect in quail egg production.

Sign in / Sign up

Export Citation Format

Share Document