scholarly journals Effects of host age and size on clutch size and sex ratio of Oomyzus sokolowskii (Hymenoptera: Eulophidae), a larval-pupal parasitoid of Plutella xylostella (Lepidoptera: Yponomeutidae).

2002 ◽  
Vol 37 (2) ◽  
pp. 319-322 ◽  
Author(s):  
Akiko Nakamura ◽  
Takashi Noda
Keyword(s):  
Sex Ratio ◽  
Clutch Size ◽  
Plutella Xylostella ◽  
Host Age ◽  
Pupal Parasitoid

scholarly journals On the virulence of the entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae (Ascomycota: Hypocreales), against the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae)

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Muhammad Shehzad ◽  
Muhammad Tariq ◽  
Tariq Mukhtar ◽  
Asim Gulzar
Keyword(s):  
Sex Ratio ◽  
Beauveria Bassiana ◽  
Entomopathogenic Fungi ◽  
Plutella Xylostella ◽  
Metarhizium Anisopliae ◽  
Insect Pest ◽  
Diamondback Moth ◽  
Economic Damage ◽  
Offspring Sex Ratio ◽  
Development Of Resistance

Abstract Background The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a noxious pest of cruciferous crops all over the world causing serious economic damage. Management of insect pest generally depends on chemical control; however, due to development of resistance against all types of insecticides, alternative approaches especially utilization of a microbial agent is inevitable. Results Potential of 2 entomopathogenic fungi (EPF), viz., Beauveria bassiana and Metarhizium anisopliae, was evaluated against 2nd and 3rd larval instars of P. xylostella by adopting leaf dip and direct spraying methods under laboratory conditions. Significant mortality rate was achieved by each fungus under adopted methodologies. However, B. bassiana was found to be more effective in both conditions than M. anisopliae. Highest mean corrected mortality (77.80%) was recorded, when spores of B. bassiana were sprayed on the 2nd instar larvae (LC50=1.78×104/ml) after the 6th day of treatment. Similarly, incase of M. anisopliae LC50 for the 2nd instar at the same methodology was 2.78×104/ml with a mortality percentage of 70.0%. Offspring sex ratio was non-significantly related to treatment concentration and methodology, except for the control. Conclusion Beauveria bassiana and M. anisopliae had potential to suppress P. xylostella infestations when applied appropriately. Present findings suggested that B. bassiana and M. anisopliae when sprayed on immatures of host insect had more effect as compared to leaf dip procedure. Furthermore, no significant effect of concentrations was observed on sex ratio.

Clutch size: a major sex ratio determinant in fig pollinating wasps?

2005 ◽  
Vol 328 (5) ◽  
pp. 471-476 ◽  
Author(s):  
Finn Kjellberg ◽  
Judith L. Bronstein ◽  
Glen van Ginkel ◽  
Jaco M. Greeff ◽  
Jamie C. Moore ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Clutch Size

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.

Host location, survival and fecundity of the Oriental rat flea Xenopsylla cheopis (Siphonaptera: Pulicidae) in relation to black rat Rattus rattus (Rodentia: Muridae) host age and sex

2002 ◽  
Vol 92 (5) ◽  
pp. 375-384 ◽  
Author(s):  
S. Mears ◽  
F. Clark ◽  
M. Greenwood ◽  
K.S. Larsen
Keyword(s):  
Sex Ratio ◽  
Rattus Rattus ◽  
Host Choice ◽  
Host Age ◽  
Xenopsylla Cheopis ◽  
Black Rat ◽  
Host Seeking ◽  
Host Sex ◽  
Host Behaviour ◽  
Age And Sex

AbstractHost choice and fecundity are two factors that may contribute to the variation in flea counts observed when assessing the potential risk of flea-borne transmission of pathogens from rodents to humans. Using the black rat, Rattus rattus Linnaeus, as host the effects of age and sex on host choice and fecundity of the Oriental rat flea, Xenopsylla cheopis Rothschild, were examined experimentally at 25°C and 80% rh. During the first two days of emergence from cocoons, female fleas dominated the sex ratio by 4:1 but from the third day onwards this switched to a male-dominated sex ratio of 4:1. The sex of the flea did not influence their host-seeking behaviour. Newly emerged fleas of both sexes were not influenced by the rat‘s presence and at seven days old both sexes demonstrated similar levels of attraction toward the rat host. The sex of the rat did not affect flea host-seeking behaviour. There was a 50–70% decline in the initial number of adult fleas during the first week after their release onto a rat host, and this decline was greatest on juvenile rats. Flea fecundity was also significantly lower on juvenile rat hosts but no differences due to the sex of the rat were observed. This experimental study supports the hypothesis that differences in flea count due to host sex, reported in field surveys, result from sexual differences in host behaviour and not from discriminatory host-seeking behaviour by X. cheopis. Differences in flea count due to host age may be affected by differences in X. cheopis fecundity, which may itself be mediated by host behaviour such as grooming.

scholarly journals Selection of Trichogramma species for controlling the Diamondback moth

2008 ◽  
Vol 26 (2) ◽  
pp. 259-261 ◽  
Author(s):  
Dirceu Pratissoli ◽  
Ricardo A Polanczyk ◽  
Anderson M Holtz ◽  
Leandro P Dalvi ◽  
Alexandre F Silva ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Plutella Xylostella ◽  
Diamondback Moth ◽  
Egg Parasitoids ◽  
Biological Characteristics ◽  
Parasitism Rate ◽  
Trichogramma Species ◽  
The One ◽  
Selection Of

Biological characteristics of the egg parasitoids Trichogramma acacioi, T. atopovirilia, and T. bennetti were studied to select the one with better performance on the control of the Diamondback moth, Plutella xylostella. Parasitism rate, viability, and sex ratio were studied. Parasitism rate ranged from 1.67 to 41.33%. T. atopovirilia and T. acacioi were respectively the most and less aggressive species. The viability ranged from 6.20% for T. acacioi to 53.34% for T. atopovirilia. There were no differences on sex ratio (p<0.05) that remained above 0,88. T. atopovirilia was the species with best performance in the laboratory when rearing on the Diamondback moth eggs.

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