Understanding the mismatch between behaviour and development in a novel host-parasitoid association

Area of Science:

• Ecology
• Evolutionary Biology
• Entomology

Background:

• Foraging parasitoid females aim to maximize fitness by selecting optimal hosts for progeny.
• Introduction of invasive species can create evolutionary traps, where cues signal suitability but development fails.
• Egg parasitoids (Scelionidae) encountering the invasive brown marmorated stink bug (Halyomorpha halys) exhibit this mismatch.

Purpose of the Study:

• To investigate the factors influencing host selection and progeny development in the native parasitoid Trissolcus euschisti when encountering the invasive Halyomorpha halys.
• To determine the relative importance of host species, egg age, egg status, and surface wash on parasitoid behavior and offspring development.

Main Methods:

• Utilized an L9 orthogonal array design for efficient assessment of multiple factors.
• Assessed and ranked the influence of host resource characteristics on parasitoid behavior (acceptance, patch residence, patch exploitation).
• Evaluated the impact of these factors on the developmental success of the progeny.

Main Results:

• Host egg age was the most significant factor influencing parasitoid behavior.
• Host egg age had the least influence on progeny development.
• The relative importance of factors assessed simultaneously shapes parasitoid decision-making.

Conclusions:

• A mismatch exists between the cues parasitoid females use for host selection and the actual suitability for progeny development.
• This mismatch can lead to maladaptive oviposition decisions, trapping parasitoids in unsuitable invasive hosts.
• Understanding the interplay of multiple cues is crucial for explaining parasitoid-host interactions and evolutionary dynamics.