Comparative biology and life tables of Trichogramma aurosum on Cydia pomonella at constant temperatures

Phytoparasitica (Impact Factor: 0.9). 04/2011; 39(2):109-119. DOI: 10.1007/s12600-010-0142-4


The influence of constant temperatures on biological parameters of German strains of Trichogramma aurosum Sugonjaev & Sorokina (Hymenoptera: Trichogrammatidae) was evaluated in the laboratory on eggs of Cydia pomonella L. (Lepidoptera: Tortricidae). Development time and longevity of all strains were decreased as temperature increased. Development
time of the strains differed significantly only when exposed to 15°, 20°, and 25°C. Cumulative fertility and longevity differed
significantly at 15° and 20°C. Realized fertility differed significantly at all constant temperatures. Emergence rates of
all strains were less than 65% and were decreased even further as temperature increased. Female-biased sex ratio ranged from
65% to 100% at all constant temperatures. The low temperature threshold for T. aurosum was 10°C and the mean number of degree-days at 15°, 20°, 25° and 30°C was 175, 183, 173 and 185, respectively. The Bavarian
strain tolerated high temperatures and had the highest parasitization capability, while the Hessian strain had the lowest
parasitization at all temperatures. Fertility life table analysis revealed a major effect of temperature on the population
growth parameters. Net reproductive rate was highest at intermediate constant temperatures in all strains, with the highest
rate recorded for the Bavarian strains at all constant temperatures. Mean cohort generation time, and population doubling
time decreased as temperature increased. The daily intrinsic rate of increase and finite rate of increase were positively
correlated with temperature. The relevance of our results is discussed in the context of climatic adaptation, intraspecific
variability and biological control.

KeywordsCodling moth–Cumulative fertility–Development time–Egg parasitoids–
Ephestia kuehniella
–Intrinsic rate of increase–Life time fertility–Longevity–Sex ratio

Download full-text


Available from: Rana Samara,
  • Source
    • "Species and strains of Trichogramma can differ in the extent to which they respond to temperature , which may contribute to their success as biocontrol agents (Thomson et al 2001). For example, variation on strains ability to survive and parasitize under different temperatures has been already recorded (Pak & Van Heiningen 1985, Pizzol et al 2010, Samara et al 2001). The thermal requirements and the temperature at which the maximum mortality was achieved were similar for T. pretiosum and T. atopovirilia. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Trichogramma pretiosum Riley and Trichogramma atopovirilia Oatman & Platner are natural enemies of Plutella xylostella (L.) in Southern Brazil. Laboratory studies to evaluate parasitoids performance under different conditions, such as temperature regimes, are necessary to assess their potential as biocontrol agents of P. xylostella. In most studies involving Trichogramma, parasitism rate is the main parameter used to evaluate parasitoid performance, ignoring that parasitoids can cause egg mortality by feeding on the host content and/or to multiple drilling without laying eggs. This study was conducted to investigate three main issues: how temperature affects T. pretiosum and T.atopovirilia development on eggs of P. xylostella, whether or not these species respond differently to temperature, and how important is the mortality they cause besides parasitism on P. xylostella. Temperature effects (from 10 to 30°C) on development, survival, parasitism rate, mortality, and total mortality caused by T. pretiosum and T. atopovirilia on eggs of P. xylostella were evaluated. Temperature affected the development time, female longevity, parasitism rate, mortality not directly related to parasitoid larval development, and total mortality caused on the host. No significant differences were recorded for the estimated thermal requirements for T. pretiosum and T. atopovirilia. However, the higher mortality caused by T. pretiosum indicates that this parasitoid is the most suitable to be used against P. xylostella. Also, the results suggest that the use of parasitism rate as the only parameter to evaluate the performance of T. pretiosum and T. atopovirilia may underestimate the potential of these parasitoids in regulating pest populations.
    Neotropical Entomology 06/2015; 44(3). DOI:10.1007/s13744-014-0263-4 · 0.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Egg parasitoids of the genus Trichogramma Westwood play an important role in the control of the velvetbean caterpillar Anticarisa gemmatalis Hübner in soybean crops in Southern Brazil. The effectiveness of Trichogramma species as biocontrol agents is dependent of several factors, but their adaptation to the climatic conditions of the region where they will be released is one of the most important. In this context, this study evaluated the effects of five constant temperatures ranging from 14 to 30°C on parasitism, age-specific survival, progeny production and longevity of Trichogramma pretiosum Riley, Trichogramma atopovirilia Oatman & Platner, Trichogramma acacioi Brun, Moraes & Soares, Trichogramma lasallei Pinto, and Trichogramma rojasi Nagaraja & Nagarkatti. We demonstrate that temperature differently affected the species of Trichogramma investigated when using eggs of the velvetbean caterpillar. We also demonstrate that T. pretiosum and T. atopovirilia are better adapted to a wide range of temperatures than the other species evaluated, and are therefore better suited as biocontrol agents for applied biological control programs of A. gemmatalis
    Neotropical Entomology 04/2014; 43(2):176-182. DOI:10.1007/s13744-013-0189-2 · 0.77 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The pupal development of Aethina tumida Murray (Coleoptera: Nitidulidae) was studied at various combinations of thermo-hygrometric soil conditions (temperatures of 16, 18, and 20 degrees C and soil water content levels of 0.37, 0.56, and 0.73 m3 water per cubic meter of dry soil) representative of southeastern Canada. Survivorship and development duration of A. tumida pupae, as well as sex ratio and life span of emerging adults, were assessed. Assays were conducted in growth chambers on an average of 50 third-instar larvae per thermo-hygrometric combination. Results show that survivorship of pupae decreased with lower temperature and higher soil water content. Pupal development time shortened as temperature increased (69-78 d at 16 degrees C, 47-54 d at 18 degrees C, and 36-39 d at 20 degrees C), but was longer in dryer soil. Optimal soil water content for pupal development was 0.56 m3 water per cubic meter of soil. We estimated that the minimum development temperature for pupae is between 10.2 and 13.2 degrees C, depending on soil water content. The sex ratio of emerging adults was influenced by soil water content. We measured one female to one male for dry and intermediately wet soils and three females to one male for wet soils. Higher soil water content reduced the life span of emerging adults by half. This study contributes to a better understanding of A. tumida population dynamics in eastern Canada.
    Journal of Economic Entomology 04/2014; 107(2):531-7. DOI:10.1603/EC13288 · 1.51 Impact Factor
Show more