Dietary Effect on Reproductive Interference in Aphidophagous Ladybird Beetles

The research highlights the significant role of diet in shaping heterospecific male reproductive behaviour and its impact on Propylea dissecta, with heterospecific males on nutrient-rich diets causing the greatest reproductive disruption. This study provides new insights into how dietary variations, particularly preferred (Aphis craccivora) and least preferred (Aphis nerii) foods, affect heterospecific male interference, demonstrating that males reared on preferred foods induce stronger reproductive interference.
To explore how the highly preferred (A. craccivora) and least preferred (A. nerii) diets of heterospecific males (C. sexmaculata) influence the mating and reproductive parameters of P. dissecta, four treatments were established: (1) a scarce diet of A. nerii, (2) an abundant diet of A. nerii, (3) a scarce diet of A. craccivora, and (4) an abundant diet of A. craccivora. In each treatment, pairs of P. dissecta and a C. sexmaculata male were placed in the same Petri dish, and mating and reproductive parameters were recorded. A total of 30 replicates were conducted per treatment.
Mating parameters, including the time to initiate mating (from mounting to aedeagus intromission) and mating duration (from intromission to dismounting), were documented. After mating, females were transferred to separate Petri dishes containing aphids. Reproductive parameters, such as the pre-oviposition period (the time before the first egg was laid), fecundity (total number of eggs laid), and egg viability, were monitored over the following seven days for 30 females per treatment.
The dataset, based on the effects of different diets of Cheilomenes sexmaculata males on Propylea dissecta, supports our findings and includes analyses of various variables, such as time to commence mating, mating duration, pre-oviposition period, average fecundity, and average percent egg viability. The results indicate that males reared on preferred diets led to higher incidences of heterospecific mating and reduced reproductive outcomes, emphasizing the substantial impact of diet on reproductive interactions between these species.