Reproductive interference and its impact on species interactions in two coexisting ladybird beetles

Area of Science:

• Ecology
• Behavioral Ecology
• Conservation Biology

Background:

• Interspecies interactions influence reproductive success, especially with heterospecific mating.
• Cheilomenes sexmaculata (Fabricius) mating status affects Propylea dissecta (Mulsant) reproductive traits.
• Previous research indicated age-dependent heterospecific male behavior towards P. dissecta.

Purpose of the Study:

• To investigate how the mating status of Cheilomenes sexmaculata males (unmated, once mated, multiply mated) affects reproductive outcomes in Propylea dissecta.
• To understand the impact of heterospecific mating on the fecundity and egg viability of P. dissecta.
• To explore the selective pressures driving reproductive strategies in coexisting biocontrol agents.

Main Methods:

• Experimental manipulation of C. sexmaculata male mating status (unmated, once mated, five times mated).
• Observation of conspecific and heterospecific mating interactions between C. sexmaculata and P. dissecta.
• Quantification of reproductive outcomes in P. dissecta, including fecundity and egg viability.

Main Results:

• Multiply mated C. sexmaculata males caused greater mating disruption in conspecific interactions but showed reduced post-mating responsiveness.
• Unmated and once-mated C. sexmaculata males induced more reproductive interference, increasing heterospecific mating with P. dissecta females.
• Heterospecific mating significantly reduced P. dissecta female fecundity and egg viability, likely due to behavioral disruption.

Conclusions:

• Male mating history in C. sexmaculata influences reproductive interference and heterospecific mating success.
• These interactions impose significant costs on P. dissecta reproduction, potentially driving selection for trait evolution.
• Understanding these dynamics is vital for optimizing biocontrol agent compatibility and integrated pest management strategies.