Effect of age and hunger on host-feeding behaviour by femaleTrichogramma euproctidis(Hymenoptera: Trichogrammatidae)

2013 ◽  
Vol 145 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Émilie Lessard ◽  
Guy Boivin
Keyword(s):  
Sex Ratio ◽  
Feeding Behaviour ◽  
Strategic Choice ◽  
Host Feeding ◽  
Feeding Frequency ◽  
Duration Distribution ◽  
Adult Parasitoid ◽  
Old Females ◽  
Effect Of Age

AbstractAdult parasitoid females can obtain proteins and lipid by consuming the haemolymph of their host. InTrichogrammaWestwood (Hymenoptera: Trichogrammatidae) species, host feeding on the host egg occurs after oviposition and leads to smaller offspring. We tested the effect of age and hunger on host-feeding behaviour of femaleTrichogramma euproctidisGirault. Young and old females, either starved, water fed, or honey fed, were observed and the host-feeding frequency, duration, distribution, and number of hosts used for nutrition were measured. The sex ratio (proportion of males) allocated to parasitised hosts where host feeding occurred and time taken to parasitise 10 hosts (indicator of female mobility) were also noted. The majority of females host fed on the first host encountered. Age had no impact on frequency, duration, number of hosts used, and mobility ofT. euproctidis. Starved females host fed longer and were less mobile. The sex ratio of the progeny emerging from the first host parasitised was more male biased when host feeding occurred. Host feeding had no effect on the sex ratio deposited elsewhere in the sequence of hosts encountered. Age of female had no effect on host feeding, possibly because host feeding incurs little cost for this species. To host feed on the first host parasitised, in which a male is allocated, is less costly in terms of fitness and represents a strategic choice for the female.

scholarly journals Real-Time Monitoring of Self-Fed Supplement Intake, Feeding Behaviour, and Growth Rate as Affected by Forage Quantity and Quality of Rotationally Grazed Beef Cattle

Animals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1129 ◽  
Author(s):  
José A. Imaz ◽  
Sergio García ◽  
Luciano A. González
Keyword(s):  
Growth Rate ◽  
Beef Cattle ◽  
Real Time ◽  
Temporal Variability ◽  
Feeding Behaviour ◽  
Nutritional Management ◽  
Feeding Frequency ◽  
High Feed ◽  
Supplement Intake

Supplement intake and liveweight (LW) data were collected daily and remotely by digital in-paddock technologies (electronic feeder (EF) and walk-over-weighing scale (WOW)) to study the effect of forage quantity and quality on the intake of a self-fed supplement (molasses-lick blocks (MLB)), LW, liveweight change (LWC), and feeding behaviour of grazing beef cattle. Fifty-two crossbred weaners were rotationally grazed or fed for 254 days on different forages: sudangrass (SG), autumn pastures (P), winter pastures with concentrate (P+C), oat crops (OC), lucerne hay (LH), and oaten hay (OH). Forage quantity and quality were measured on the day of entry (high feed availability) and exit (low feed availability) stages of grazing or hay delivery. The intake of MLB was 111% higher (p < 0.05) at low compared to high feed availability, and this was also reflected in the feeding behaviour of animals (e.g., greater feeding frequency and rate). Moreover, there was a large temporal variability of daily MLB intake (Coefficient of variation (CV) = 146.41%). Supplementing MLB improved LWC only with SG, P, or OH (p < 0.05). The behaviour of animals around MLB reflects changes in feed quantity and quality and could be used to enhance cattle grazing and nutritional management in real time.

Unequal sex ratios in longline catches

2001 ◽  
Vol 81 (1) ◽  
pp. 187-188 ◽  
Author(s):  
P. Wirtz ◽  
T. Morato
Keyword(s):  
Sex Ratio ◽  
Feeding Behaviour ◽  
Sex Ratios ◽  
The Other ◽  
Size Difference ◽  
Longline Fishery ◽  
Significant Bias ◽  
Different Response ◽  
The Given

There is sometimes a significant bias in the sex ratio of fish caught by longline. Usually, more females than males are caught. The possible reasons for unequal sex ratios in longline catches are listed and discussed. One sex could be more common in the area where the fishery takes place because there really is an unequal sex ratio in the population or because the other sex preferentially occurs in different places. Alternatively, longline fishery might preferentially catch one of the sexes. This could be a result of size difference between the sexes and thus a different response to the given hook size or bait size. Finally, sexes could differ in their feeding behaviour. There is growing evidence that females—not only of fish—are ‘energy maximizers’: they find food faster and spend more time feeding than do males. Thus, fishing methods using bait are likely to catch a higher proportion of females than fishing methods that do not use bait.

Effect of temperature of storage and age of fowl eggs on hatchability and sex ratio, growth, and viability of the chickens

1960 ◽  
Vol 11 (4) ◽  
pp. 664 ◽  
Author(s):  
MW McDonald
Keyword(s):  
Relative Humidity ◽  
Sex Ratio ◽  
Storage Temperature ◽  
Lower Number ◽  
The Other ◽  
Effect Of Temperature ◽  
White Leghorn ◽  
Rapid Fall ◽  
Cent Relative Humidity ◽  
Effect Of Age

Fertile White Leghorn eggs were stored for periods ranging from 24 hr to 7 days in environments controlled at 40, 60, or 80°F and 70 per cent. relative humidity. The eggs were then incubated, and observations on numbers of incubator clears and dead embryos at 10 days and again at 17 days, numbers of chickens hatched, weight at hatching, sex ratio, weight of pullets at 14 days of age, and mortalities were recorded. Eggs stored at 40 and 60°F showed no effect of age of egg on number of clears, dead embryos, or number of chickens hatched. Eggs stored at 80°F showed a rapid fall in number of chickens hatched with age of egg before incubation, this effect being produced by increases in number of clears and dead embryos. Storage at 40°F produced a lower number of chickens hatched than at 60°F, owing to a higher number of incubator clears. There was no difference in sex ratio between chickens hatched from eggs stored at 60 and 80°F, neither departing significantly from 50 per cent. pullets. However, storage at 40°F produced significantly more pullets than cockerels, 54.6 per cent. of the chickens being pullets. Storage temperature and age of egg did not affect the hatching weight of the chickens, but when 14 days old, pullets from the eggs stored at 80°F were significantly heavier than pullets from the other groups.

IRRADIATION OF SPERM AND OOCYTES IN ONCOPELTUS FASCIATUS (HEMIPTERA: LYGAEIDAE): SEX RATIO, FERTILITY, AND CHROMOSOME ABERRATIONS IN THE F1 PROGENY

1973 ◽  
Vol 15 (4) ◽  
pp. 713-721 ◽  
Author(s):  
L. E. LaChance ◽  
R. D. Richard
Keyword(s):  
Sex Ratio ◽  
Gamma Irradiation ◽  
Chromosome Aberrations ◽  
Oncopeltus Fasciatus ◽  
X Rays ◽  
Virtual Absence ◽  
Chromosome Translocations ◽  
F1 Progeny ◽  
Old Females

Adult Oncopeltus fasciatus were irradiated as 7- to 8-day-old males, and as 3- to 4- or 10- to 12-day-old females with doses of 8 and 20 krad of gamma irradiation and 200 R of X-rays, respectively. Treated bugs were outcrossed to untreated bugs, and F1 progeny derived from irradiated sperm and from prophase and metaphase oocytes were studied. All treated bugs were less fertile than the controls, but none of the treatments produced full sterility. Among the F1 generation from the three types of crosses, there was no significant deviation from a 50:50 sex ratio.When F1 males were outcrossed to untreated females, only the males derived from irradiated sperm were semisterile; F1 males derived from the treated oocytes were as fertile as the controls. The semisterility of the F1 males was correlated with chromosome translocations and fragments in the spermatocytes. The virtual absence of these aberrations in the testes of F1 males derived from irradiated oocytes suggests that these aberrations are not induced in oocytes, are repaired, or are not included in the maternal pronucleus after irradiation of meiotic oocytes.

scholarly journals Feeding frequency on growth and male percentage during sexual reversion phase of Nile tilapia

2012 ◽  
Vol 13 (4) ◽  
pp. 1133-1142 ◽  
Author(s):  
Fábio Meurer ◽  
Robie Allan Bombardelli ◽  
Patrícia Santana da Paixão ◽  
Lilian Carolina Rosa da Silva ◽  
Lilian Dena dos Santos
Keyword(s):  
Sex Ratio ◽  
Nile Tilapia ◽  
Sex Reversal ◽  
Feeding Frequency ◽  
Randomized Design ◽  
Nile Tilapia Oreochromis Niloticus ◽  
Reversal Phase ◽  
Commercial Breeding ◽  
Suitable Index ◽  
Effect Of Feeding

The sex reversal is one of the most important stages for the commercial breeding of Nile tilapia in relation to the problems arising from early breeding of this species in cultivation tanks. The objective was to determine the effect of feeding frequency on growth and sex ratio of Nile tilapia (Oreochromis niloticus) during the sex reversal phase. Five hundred Nile tilapia fry were used and stocked in twenty-five plastic aquaria (36L) in a completely randomized design with five treatments and five replicates. The treatments were: one feeding (10h), two feeding (09h and 17h), three feeding (09h; 13h and 17h), four feeding (07h; 10h; 13h and 17h), and five feeding (07h; 09h; 11h; 15h and 17h). The feeding frequency affected sex ratio of male fingerlings, where the treatments with four and five feedings provided similar values, but higher (P<0.01) than other treatments. It is recommended feeding frequency at least four times a day to provide lots with suitable index of sex reversal for cultivation.

DEVELOPMENT OF TIPHODYTES GERRIPHAGUS (HYMENOPTERA: SCELIONIDAE) IN LIMNOPORUS DISSORTIS EGGS (HEMIPTERA: GERRIDAE)

1999 ◽  
Vol 131 (2) ◽  
pp. 219-228 ◽  
Author(s):  
João M. Sousa
Keyword(s):  
Sex Ratio ◽  
Larval Stage ◽  
Host Feeding ◽  
Larval Instars ◽  
Pupal Period ◽  
Laboratory Conditions ◽  
Total Length ◽  
Preimaginal Development ◽  
First Instar ◽  
Mandible Length

AbstractInvestigations of preimaginal development in Tiphodytes gerriphagus Marchal reveal two larval instars, based on counting exuviae and comparing mandible length during development within Limnoporus dissortis Drake & Harris eggs. Tiphodytes gerriphagus eggs are stalked, as is typical of scelionids, and are 282.6 ± 3.48 μm (mean ± SE) long. The chorion ruptures at 8–9 h postoviposition and releases a nonfeeding embryo into the host. Feeding begins at 18–20 h postoviposition, after the embryonic cuticle is shed and a fully differentiated and active larva is released. The first larval stage is teleaform and lasted up to 5 days postoviposition, and its total length increased from 183.6 ± 3.35 to 517.0 ± 14.67 μm. The second larval stage is hymenopteriform and lasted from 5 to 13 days postoviposition, and grew from 920.2 ± 24.65 to 1352.4 ± 11.89 μm total length before pupating. The pupal period lasted about 11 days, with male pupae being shorter and thinner than female pupae. These findings differ from previous descriptions of T. gerriphagus, and it is suspected that the first instar was mistakenly divided into two stadia. The sex ratio under laboratory conditions was female biased (22% males), and males were smaller but did not emerge significantly earlier than females.

scholarly journals The suitability of biotypes Q and B ofBemisia tabaci(Gennadius) (Hemiptera: Aleyrodidae) at different nymphal instars as hosts forEncarsia formosaGahan (Hymenoptera: Aphelinidae)

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1863 ◽  
Author(s):  
Xin Liu ◽  
Youjun Zhang ◽  
Wen Xie ◽  
Qingjun Wu ◽  
Shaoli Wang
Keyword(s):  
Biological Control ◽  
Feeding Rate ◽  
Trialeurodes Vaporariorum ◽  
Host Feeding ◽  
Encarsia Formosa ◽  
Greenhouse Crops ◽  
Commercial Strain ◽  
Promising Tool ◽  
Adult Parasitoid ◽  
Biotype B

Encarsia formosaGahan (Hymenoptera: Aphelinidae) is a solitary endoparasitoid that is commercially reared and released for augmentative biological control of whiteflies infesting greenhouse crops. In most areas in China, the invasive and destructive whiteflyBemisia tabaci(Gennadius) (Hemiptera: Aleyrodidae) biotype Q has replacedB. tabacibiotype B and has become dominant between the two. A better understanding of the suitability of different nymphal instars ofB. tabacibiotypes Q and B as hosts forE. formosais needed to improve the use of this parasitoid for biological control. Parasitism of the four nymphal instars ofB. tabacibiotypes Q and B by the commercial strain ofE. formosamass reared onTrialeurodes vaporariorum(Westwood) (Hemiptera: Aleyrodidae) was assessed in the laboratory. The results indicated thatE. formosaparasitized and successfully developed on all instars of both biotypes but performed best on the 3rd instar ofB. tabacibiotype B and on the 2nd, 3rd, and 4th instars ofB. tabacibiotype Q. The host-feeding rate of the adult parasitoid was generally higher on nymphal instars ofB. tabacibiotype Q than on the corresponding nymphal instars of biotype B and was significantly higher on the 2nd and 3rd instars. For both whitefly biotypes, the parasitoid’s immature developmental period was the longest on the 1st instar, intermediate on the 2nd and 3rd instars, and the shortest on the 4th instar. The parasitoid emergence rate was significantly lower on the 1st instar than on the other three instars and did not significantly differ betweenB. tabacibiotype B and biotype Q. Offspring longevity was greater on the 3rd and 4th instars than on the 1st instar and did not significantly differ between the twoB. tabacibiotypes. The results indicate that commercially-producedE. formosacan parasitize all instars ofB. tabacibiotypes B and Q, making this parasitoid a promising tool for the management of the two biotypes ofB. tabacipresent in China.

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