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18Cannibalism has been reported in a large proportion of coccinellids in fields as well as in 19 laboratories but studies involving mate preferences and potential benefits of cannibalism on 20 reproduction in Menochilus sexmaculatus Fabricius (Coleoptera: Coccinellidae)have yet not 21 been done. Thus, we assessed the effect of conspecific egg cannibalism on mate preferences 22 and reproductive outputs including offspring development. Higher mate preferences were 23 recorded for non-cannibal mates (fed on A. craccivora) than cannibal ones (fed on conspecific 24 eggs). Mating parameters significantly influenced by cannibalism. Time to commence mating 25 lasted less for homogeneous diet pairs than heterogeneous diet pairs. Longer copulation 26 duration and higher fecundity were recorded when one of the individuals in mating pair or both 27 was a non-cannibal. Egg viability did not differed significantly in all reciprocal crosses. Total 28 developmental durations of offspring were similar for all mating pairs. 29 Keywords: aphids, cannibal and non-cannibal, fecundity, egg viability, development. 30 31 109 simultaneous choice of males from both dietary regimes. Each mate preference treatment was 110 replicated 20 times. 111 The mating parameters, viz. time of commencement of mating and copulation durations of each 112 pair were recorded. In order to assess the effect of cannibalism on reproductive performance, 113 the following combinations obtained from both the female and male mate preference setup 114 were observed, Fnc × Mnc, Fnc × Mc, Fc × Mnc, Fc × Mc (F and M representing female and male 115 respectively; 'nc' and 'c' representing non-cannibal and cannibal, respectively). 116After the termination of mating, the male was removed and the females were maintained on 117 their pre-assigned diet. Daily oviposition and hatching were recorded for the next 5 days 118 Statistical analysis 119 The chi-square (χ2) goodness-of-fit analysis was used to test the null hypothesis of random 120 mating. Data on mating and reproductive outputs, i.e. time of commencement of mating, 121 copulation duration, fecundity, egg viability, and developmental durations were first tested for 122 normality (Kolmogorov-Smirnoff). On being found normally distributed, each of the previous 123 measurements was subjected to one-way analysis of variance (ANOVA) with diet as 124 independent factors. The analysis was followed by the comparison of means using post hoc 125 235 Avent, T.D., Price, T.A.R., Wedell, N., 2008. Age-based female preference in the fruit fly 236 Drosophila pseudoobscura. Anim.

Cannibalism is taxonomically widespread and has a large impact on the individuals fitness and population dynamics. Thus, identifying how the rates of cannibalism are affected by different ecological cues is crucial for predicting species evolution and population dynamics. In current experiment, we investigated how victim relatedness affects the cannibalistic tendencies of different life stages of ladybird, Menochilus sexmaculatus, which is highly cannibalistic. We provided larval instars and newly emerged adults of M. sexmaculatus with a choice of sibling, half-sibling and non-sibling conspecific eggs as victim of cannibalism. First victim cannibalised and latency to cannibalise were observed along with total number of victims cannibalised after 24 hours. First preference of victim did not differ with life stages of the cannibals though the number of victims cannibalized did increase with advancement in stage. Percentage of total eggs cannibalised also varied significantly with life stage and victim relatedness. First and second instars tend to cannibalise more percentage of siblings and non-sibling eggs while third instars cannibalised more percentage of non-sibling eggs; fourth instars and adults on the other hand cannibalised highest percentage of eggs irrespective of their relatedness. Insignificant effect of victim relatedness was observed on latency to cannibalise eggs, though it varied significantly with the cannibals life stage. Shortest latency to cannibalise was recorded for first instars and longest for adults and second instars. In conclusion, kin recognition and its avoidance is stage-specific, with fourth instar and newly emerged adults being less discriminatory as compared to early stages owing to increased evolutionary survival pressure.

Cannibalism has been widely reported across taxa. However, the heritability and expression of cannibalistic traits have been least explored. The variation in the expression of cannibalism is likely to exist amongst the population affecting the propensity of cannibalism. Thus, to know whether the mother has any role in the transgenerational transmission of this trait in a ladybird beetle, Menochilus sexmaculatus, we studied the interaction between maternal and offspring prey preferences and its effect on, development duration and body weight of offspring over generations. An insignificant effect of maternal dietary history on offspring prey preference was observed across generations except for the non-cannibalistic adults who significantly preferred aphids over eggs. The long-term detrimental effect of cannibalism was found in cannibals with increased developmental duration and decreased body weight of offspring over generations. In conclusion, the results show that maternal diet did not affect the offspring preferences in M. sexmaculatus but cannibalism had a profound generational effect on the cannibalistic propensity, development and body weight of offspring across generations shows that larval dietary history and nutritional composition of prey contribute to the expression of cannibalistic behaviour across generations.