Transgenic Maize Pollen Affects Lady Beetle Fitness but with Trade-Offs

Strategic Insights -

Lady beetles, especially the Variegated Lady Beetle, are crucial aphid predators in the Mediterranean area, and their diet comprises mainly aphids but also plant pollen. A study conducted by researchers from the Alma Mater Studiorum - University of Bologna, with financial support from the European Commission Joint Research Centre, has explored the effects of transgenic maize pollen expressing Cry1Ab toxin on the fitness of H. variegata. The study demonstrates that the consumption of Bt-maize pollen by adults of H. variegata does not significantly affect their fitness, but it shows that this outcome is a result of a trade-off among vital rates such as age-specific fecundity and survival probability that are positively or negatively influenced.

Key Takeaways:

  • The Variegated Lady Beetle, Hippodamia variegata Goeze, is a common aphid predator in the Mediterranean area that feeds preferably on aphids but can use plant pollen as a supplemental food source.
  • The consumption of Bt-maize pollen by adults of H. variegata does not significantly affect their fitness.
  • However, demographic analyses showed that some effects of Bt pollen exposure occurred, such as a higher expected lifetime reproduction for Bt-pollen-fed females, but a reduced life expectancy for their offspring.
  • The study used an experimental methodology to provide pollen to the coccinellids and quantify the amount of pollen eaten.
  • Both standardized laboratory bioassays and demographic approach by means of an age-structured matrix population model were performed to evaluate the potential effects of Bt-maize pollen on the fitness of H. variegata.

Statistics:

  • The study was conducted by researchers from the Alma Mater Studiorum - University of Bologna, Italy.
  • Financial support for this research came from the European Commission Joint Research Centre.
  • The study concluded that the Bt-pollen-fed females had a higher expected lifetime reproduction, but a reduced life expectancy for their offspring.
  • The results showed that the consumption of Bt-maize pollen causes a lower increase in H. variegata population since a reduction of offspring survival seems only partially outweighed by increased female fecundity.

Sources:

  • NewsRx LLC, "Researchers at Alma Mater Studiorum - University of Bologna Release New Data on Agriculture (Dietary Effects of Transgenic Mon810 Bt-maize Pollen On Fitness of hippodamia Variegata Goeze)", Agriculture Week, 2025, p 402.
  • "Dietary Effects of Transgenic Mon810 Bt-maize Pollen On Fitness of hippodamia Variegata Goeze", Arthropod-Plant Interactions, 2025;19(4).