Biology subjects

Omkar, O.

Publications and source records attributed to Omkar, O..

4 recordsLinked to original sources

bioRxiv2026

Relatedness and last male sperm precedence in Cheilomenes sexmaculata: Implications for inbreeding avoidance

Avoidance to mate with relatives is a common evolutionary strategy, as it helps maintain genetic diversity and overall fitness within populations. Females often prefer unrelated males to mitigate the risks associated with inbreeding, such as the expression of deleterious recessive alleles. This preference can involve various post-copulatory mechanisms through which females bias paternity towards males with potentially better genes. The phenomenon of last male sperm precedence, where the last male to mate with a female tends to sire the majority of offspring, is well-documented in ladybird beetles. However, how relatedness affects this phenomenon remains unclear. This study aims to investigate whether paternity share is altered when the last male to mate with a female is related to her. By conducting double mating experiments with two different morphs (typical and intermediate) as phenotypic markers, we seek to determine if relatedness disrupts last male sperm precedence. It was hypothesised that females of Cheilomenes sexmaculata will prefer unrelated males over related ones, irrespective of mating order, potentially breaking down the last male sperm precedence. This preference for unrelated males was reflected in our results with unrelated males exhibiting enhanced reproductive success. Females were more fecund and exhibited higher egg viability with unrelated males. Greater paternity share was observed for unrelated males when the second male was related to the female. This study highlights the dynamic nature of sperm precedence and the role of mate quality in female mate choice, emphasizing the importance of inbreeding avoidance in sexual selection.

zoology↗

bioRxiv2023

Heterospecific physical interference modulates the reproductive attributes of a ladybird beetle

Propylea dissecta and Cheilomenes sexmaculata (Coleoptera: Coccinellidae), are similar sized, co-ocurring aphidophagous insects that share common resources. We conducted the current study to observe the phenomenon of reproductive interference and effect of presence of heterospecific adults (C. sexmaculata) on the reproductive output of P. dissecta. For this, we used two reciprocal mating combinations of heterospecifics. The first heterospecific combination used P. dissecta males with C. sexmaculata females and the second heterospecific mating combination used P. dissecta females with C. sexmaculata males. To further examine the effect of C. sexmaculata male on P. dissecta female, we used mixed mating treatments (C. sexmaculata male with conspecific pair of P. dissecta). Our results suggested that (1) in the first heterospecific mating combination, mating did not commence between P. dissecta male C. sexmaculata female, while in the second heterospecific mating combination, mating was recorded between P. dissecta female and C. sexmaculata male, (2) C. sexmaculata male interferes the conspecific mating in P. dissecta through multiple mating attempts which resulted in reduced fitness and reproductive success of P. dissecta. Overall, we illustrated the negative effects of reproductive interference caused by C. sexmaculata on the reproductive output (fecundity and egg viability) of P. dissecta.

zoology↗

bioRxiv2020

Mating system modulates mate selection in aphidophagous ladybird beetle, Menochilus sexmaculatus

ABSTRACTMate competition and selection of mates is strongly influenced by the organism’s mating system. Monogamous matings provide more benefits as compared to polygamous matings. However, it has been proven that in polygamous systems, females gain benefits from the males, therefore indulging in multiple mating, leading males to access maximum females. In zigzag ladybird, Menochilus sexmaculatus, mate choice has been studied on several pre-and postcopulatory factors. However, mate choice as a function of mating system is still remains untouched. In the present study, we hypothesised that the mating system modulates mate selection of beetles. Adults were held in different mating systems and then males and females were tested in mate choice trials. Polygynous males were more preferred over monogynous males. However, males preferred monandrous females over polyandrous females. In a second experiment, we also included relatedness as additional factor. In female mate choice trials, females preferred unrelated monogynous males which were earlier rejected over related polygynous and in male mate choice trials, males preferred unrelated polyandrous females over related monandrous females. The results were not confined only to mate choice but significant effect was also observed on time to commence mating, copulation duration, fecundity and percent egg viability.View Full Text

zoology↗

bioRxiv2020

Effect of egg cannibalism on mating preferences and reproductive fitness of Menochilus sexmaculatus Fabricius (Coleoptera: Coccinellidae)

Cannibalism has been reported in a large proportion of coccinellids in fields as well as in laboratories but studies involving mate preferences and potential benefits of cannibalism on reproduction in Menochilus sexmaculatus Fabricius (Coleoptera: Coccinellidae)have yet not been done. Thus, we assessed the effect of conspecific egg cannibalism on mate preferences and reproductive outputs including offspring development. Higher mate preferences were recorded for non-cannibal mates (fed on A. craccivora) than cannibal ones (fed on conspecific eggs). Mating parameters significantly influenced by cannibalism. Time to commence mating lasted less for homogeneous diet pairs than heterogeneous diet pairs. Longer copulation duration and higher fecundity were recorded when one of the individuals in mating pair or both was a non-cannibal. Egg viability did not differed significantly in all reciprocal crosses. Total developmental durations of offspring were similar for all mating pairs.

animal behavior and cognition↗