Understanding why animals choose one food over another is one of the key questions underlying the fields of behaviour ecology. This study aims to test if ladybird beetle, Propylea dissecta Mulsant (Coleoptera: Coccinellidae) can forage selectively for nutrients in order to redress specific nutritional imbalances to maximise their fitness. We hypothesised that the presence of more food choices leads to bad decisions in terms of their food selection which ultimately negatively affects the mating and reproductive parameters of P. dissecta. To test this, we first manipulated the predator's nutritional status by rearing them in five separate dietary groups from first instar larvae to newly emerged adult stage. Thereafter, we tested their food choice between five different foods, i.e. Aphis craccivora Koch, Aphis nerii Boyer de Fonsclombe, conspecific eggs, heterospecific eggs and mixed pollen grains, equidistantly placed in a Petri dish. Based on the food choice of the newly emerged adults, they were reared on the chosen diet for 10 days. Thereafter, adults were paired with their opposite sex (collected from stock culture reared on A. craccivora) and mating and reproductive parameters were recorded. Our results suggested that the variety of food did not affect the food choice of ladybird beetle, P. dissecta. They tend to choose their natural diet, i.e. aphid in each dietary regime. We found that previous dietary regime, i.e. larval dietary regime, significantly influences the mating and reproductive parameters of both the male and female except for the time to commence mating by the male. Food choices of adult beetles were found to significantly influence the time to commence mating, average fecundity and per cent egg viability in males and only mating duration in females. Our findings suggest that P. dissecta consistently made optimal decisions when facing various food choices. They consistently preferred their natural and preferred food choice over others, indicating a strong food selection behaviour.

Jatropha (Jatropha curcas L.) is a shrub that produces non-food oil and can potentially be used for biodiesel production. An interspecific cross was made between J. curcas and peregrina (J. integerrima) to increase genetic diversity. Interestingly, male sterility was observed in the F2 population. Out of the 445 F2 plants, five, namely, ms-1 to ms-5, exhibited male sterility, characterized by unopened and distorted stamens without pollen. The parental jatropha, peregrina, F1 and F2 had fertile pollen grain rates of 90.61%, 96.39%, 81.46% and 75.39%, respectively. To verify the fertility of the pistils in the male sterile plants, they were pollinated through selfing, opening and hand crossing with fertile pollen. All of the ms lines experienced seed abortion with or without fruit, except for ‘ms-5’, which produced seed.

Abstract In seed formation the role of ethylene has received little attention. The data available on zygotic embryogenesis suggest an association of the ethylene biosynthetic pathway and seed maturation. Over the course of dicot embryogenesis, ACC-oxidase mRNA can be expressed in the cotyledons and embryonic axis. However, as maturation proceeds, cotyledonary ACC-oxidase expression disappears. In some seeds that develop primary dormancy, ethylene synthesis can be among the prerequisites for breaking dormancy. Moreover, the persistence of dormancy may be related to the difficulty of the embryonic axis to produce the necessary ethylene levels or to low tissue sensitivity. The use of inhibitors of ethylene biosynthesis or its action has provided data implicating an ethylene requirement for seed dormancy or germination in some species. However, the role of ethylene in germination remains controversial. Some authors hold that gas production is a consequence of the germination process, while others contend that ethylene production is a requirement for germination. Furthermore, among seeds that require ethylene, some are extremely sensitive to the gas, while others require relatively high levels to trigger germination. Recent studies with Xanthium pennsylvanicum seeds suggest that β-cyanoalanine-synthase is involved in ethylene-dependent germination. In addition, regulation of the partitioning of S-adenosyl-L-methionine (AdoMet) between the ethylene vs polyamine biosynthetic pathways may be a way of controlling germination in some seeds. Such regulation may also apply to the reversal of seed thermoinhibition, which can occur when polyamine synthesis is inhibited, thereby strongly channelling AdoMet towards ethylene. The biological models and approaches that may shed additional light on the role of ethylene during seed germination are presented.