Developmental Time, Sex Ratio, and Longevity of Amitus fuscipennis MacGown & Nebeker (Hymenoptera: Platygasteridae) on the Greenhouse Whitefly

2000 ◽  
Vol 18 (2) ◽  
pp. 94-100 ◽  
Author(s):  
Maria R Manzano ◽  
Joop C van Lenteren ◽  
Cesar Cardona ◽  
Yvonne C Drost
Keyword(s):  
Sex Ratio ◽  
Developmental Time ◽  
Greenhouse Whitefly ◽  
Amitus Fuscipennis

Host Age Effects on Ovipositional and Developmental Biology of Baryscapus chrysopae (Hymenoptera: Eulophidae), a Parasitoid of Chrysopid Larvae

1995 ◽  
Vol 30 (2) ◽  
pp. 287-293
Author(s):  
John R. Ruberson ◽  
Timothy J. Kring
Keyword(s):  
Developmental Biology ◽  
Sex Ratio ◽  
Developmental Time ◽  
Age Effects ◽  
Host Age ◽  
Larval Stages ◽  
Chrysoperla Rufilabris ◽  
Host Stage ◽  
Gregarious Parasitoid

The parasitoid, Baryscapus (=Tetrastichus) chrysopae (Crawford), is a widely-distributed gregarious parasitoid of chrysopid larvae. The ovipositional and developmental biology of this parasitoid in relation to the stage of its host, Chrysoperla rufilabris (Burmeister), was examined. Female B. chrysopae attacked all larval stages of the host tested (instars 1 to 3), and paralyzed all hosts soon after mounting and stinging. During the host's paralysis, females oviposited in and fed on hosts. The time females spent on hosts was directly related to host stage. All hosts recovered from paralysis. Parasitoid developmental time was inversely related to host stage and ranged from 27.5 d in 1-d-old hosts to 20.5 d in 10-d-old hosts. Most development of parasitoid larvae appears to occur after the host has spun its pupal cocoon. The number of parasitoids produced per host was unrelated to host stage, ranging from 10.5 (in 1-d-old hosts) to 14.2 (in 7-d-old hosts) parasitoids per host. The sex ratio was skewed toward females (81.6% pooled across host stages) and was unrelated to host stage. The developmental biology of B. chrysopae appears to be well synchronized with that of its host.

Environmental regulation of sex determination in reptiles

1988 ◽  
Vol 322 (1208) ◽  
pp. 19-39 ◽  
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Growth And Development ◽  
Incubation Temperature ◽  
Sex Differentiation ◽  
Developmental Time ◽  
Alligator Mississippiensis ◽  
Phylogenetic Implications ◽  
History Of ◽  
Determining Factor

The various patterns of environmental sex determination in squamates, chelonians and crocodilians are described. High temperatures produce males in lizards and crocodiles but females in chelonians. Original experiments on the effects of incubation at 30 °C (100% females) or 33 °C (100% males) on development in Alligator mississippiensis are described. These include an investigation of the effect of exposing embryos briefly to a different incubation temperature on the sex ratio at hatching, and a study of the effects of 30 °C and 33 °C on growth and development of alligator embryos and gonads. A 7-day pulse of one temperature on the background of another was insufficient to alter the sex ratio dramatically. Incubation at 33 °C increased the rate of growth and development of alligator embryos. In particular, differentiation of the gonad at 33 °C was enhanced compared with 30 °C. A hypothesis is developed to explain the mechanism of temperature-dependent sex determination (TSD) in crocodilians. The processes of primary sex differentiation are considered to involve exposure to a dose of some male-determining factor during a specific quantum of developmental time during early incubation. The gene that encodes for the male- determining factor is considered to have an optimum temperature (33 °C). Any change in the temperature affects the expression o f this gene and affects the dose or quantum embryos are exposed to. In these cases there is production of females by default. The phylogenetic implications of TSD for crocodilians, and reptiles in particular, are related to the life history of the animal from conception to sexual maturity. Those animals that develop under optimal conditions grow fastest and largest and become male. A general association between the size of an animal and its sex is proposed for several types of vertebrate.

Life table parameters and development of Neoseiulus longispinosus (Acari: Phytoseiidae) reared on citrus red mite, Panonychus citri (Acari: Tetranychidae) at different temperatures

2017 ◽  
Vol 22 (9) ◽  
pp. 1316 ◽  
Author(s):  
Nguyen Duc Tung ◽  
LUONG THI HUYEN ◽  
DANG HUONG LAN ◽  
CAO VAN CHI ◽  
PATRICK DE CLERCQ ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Intrinsic Rate ◽  
Developmental Time ◽  
Predatory Mite ◽  
Intrinsic Rate Of Increase ◽  
Panonychus Citri ◽  
Citrus Red Mite ◽  
Rate Of Increase ◽  
Red Spider Mite ◽  
Neoseiulus Longispinosus

Development time, survival, reproduction, and sex ratio were determined for the predatory mite Neoseiulus longispinosus (Evans) at six constant temperatures (20, 25, 27.5, 30, 32.5 and 35 oC) reared on citrus red spider mite Panonychus citri (McGregor). No predatory mite reached adulthood at 35oC. All female and male immature stages of N. longispinosus developed significantly faster as the temperature increased from 20to 30 oC, but development slowed down as the temperature exceeded 30 oC. The mean total developmental time of females was longest at 20 °C (9.73 days), followed by 25oC (5.67 days), 27.5oC (4.46 days), and 32.5 oC (4.55 days) and was shortest at 30oC (3.69 days). The oviposition rate and lifetime fecundity were highest at 27.5 oC (2.80 eggs/female/day and 43.76 eggs/female, respectively) and lowest at 20 oC (0.78 eggs/female/day and 21.64 eggs/female, respectively). However, temperature had no influence on the sex ratio of offspring with the proportion of females ranging from 0.62 to 0.65. The intrinsic rate of increase (r) of N. longispinosus averaged 0.323, 0.303, 0.267, 0.189 and 0.107 females female−1 day−1 at 30, 27.5, 32.5, 25, and 20°C, respectively. These values suggested that the most optimal temperatures for the population growth of N. longispinosus were between 27.5 and 30oC. 

Developmental time, longevity, reproductive capacity and sex ratio of the mealybug parasitoidAnagyrussp. nr.pseudococci(Girault) (Hymenoptera: Encyrtidae)

2012 ◽  
Vol 22 (7) ◽  
pp. 737-745 ◽  
Author(s):  
Pompeo Suma ◽  
Ramzi Mansour ◽  
Ivan La Torre ◽  
Abdalbaset A. Ali Bugila ◽  
Zvi Mendel ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Developmental Time ◽  
Reproductive Capacity

scholarly journals Proximate mechanisms of drought resistance in Phytoseiulus persimilis eggs

2019 ◽  
Vol 79 (3-4) ◽  
pp. 279-298
Author(s):  
Sophie Le Hesran ◽  
Thomas Groot ◽  
Markus Knapp ◽  
Jovano Erris Nugroho ◽  
Giuditta Beretta ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Chemical Composition ◽  
Sex Ratio ◽  
Water Loss ◽  
Compatible Solutes ◽  
Phytoseiulus Persimilis ◽  
Developmental Time ◽  
Gas Chromatography Mass Spectrometry ◽  
External Structure ◽  
Drought Resistant

AbstractUnder drought stress, Phytoseiulus persimilis females are able to lay drought-resistant eggs through an adaptive maternal effect. The mechanisms making these eggs drought resistant still remain to be investigated. For this purpose, we studied the physiological differences between drought-resistant and drought-sensitive eggs. We compared the volume and the surface-area-to-volume ratio (SA:V) of the eggs, their sex ratio, their chemical composition (by gas chromatography-mass spectrometry), their internal and external structure [by scanning electron microscope (SEM) and transmission electron microscope (TEM) images], and their developmental time. Our results show that drought-resistant and drought-sensitive eggs have a different chemical composition: drought-resistant eggs contain more compatible solutes (free amino acids and sugar alcohols) and saturated hydrocarbons than drought-sensitive eggs. This difference may contribute to reducing water loss in drought-resistant eggs. Moreover, drought-resistant eggs are on average 8.4% larger in volume, and have a 2.4% smaller SA:V than drought-sensitive eggs. This larger volume and smaller SA:V, probably the result of a higher water content, may make drought-resistant eggs less vulnerable to water loss. We did not find any difference in sex ratio, internal or external structure nor developmental time between drought-resistant and drought-sensitive eggs. These results mark the first step in the understanding of the strategies and the energetic costs involved in the production of drought-resistant eggs in P. persimilis females.

scholarly journals Effect of Air Humidity on Sex Ratio and Development of LadybirdHarmonia axyridis(Coleoptera: Coccinellidae)

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Oldřich Nedvěd ◽  
Plamen Kalushkov
Keyword(s):  
Sex Ratio ◽  
Acyrthosiphon Pisum ◽  
Harmonia Axyridis ◽  
Survival Rates ◽  
Developmental Time ◽  
Food Type ◽  
Air Humidity ◽  
Strong Trend ◽  
Relative Air Humidity ◽  
Adult Mass

Length of development of larvae and pupae of the invasive alien ladybird beetleHarmonia axyridis, their survival rates, sex ratio, and fresh mass of the emerged adults were measured at three contrasting levels of relative air humidity: 30, 60, and 90%, 25°C and photoperiod 16L : 8D. Overall sex ratio was 51%, but there was a strong trend for higher proportion of males at low humidity and higher proportion of females at high humidity. Survival rate, larval developmental time, and adult mass were all differently influenced by air humidity depending on the food type. In individuals fed with aphidAcyrthosiphon pisumthere was a trend for better survival, shorter development, and higher mass gained at higher humidity. These trends were opposite or nonsignificant in individuals fed with frozen eggs of mothEphestia kuehniella.

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