Phenotypic plasticity (PP) is the ability of an organism with the same genotype to produce a range of phenotypes in response to different environments. PP results from the interaction of the gene with environmental signals, so according to the concept of PP, nature and nurture cannot be separated from each other. Many factors can act as a cue or stimulus to initiate PP and can originate internally (e.g. presence of pathogens etc.) or externally (e.g. photoperiod etc.). Signals tend to be harmless stimuli (such as photoperiod) with no direct effect on the individual but induce adaptive plasticity by predicting future environmental conditions, while harmful agents such as toxins are considered stimuli, although the division between these two is blurred. Phenotypic plasticity has been shown to be adaptive for the organisms that express it. The environment is constantly changing and all living things are susceptible to the effects of abiotic and biotic factors. The only way an individual can adapt to a changing environment is to change their phenotype. This has been demonstrated in a variety of organisms and studied extensively in insects. Butterflies that have a shorter generation time and are found in a diverse seasonal environment are also phenotypically plastic for various traits, such as wing coloration, body size, and pupal coloration. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay However, studies on PP, especially on the initial stages (e.g., pupal coloration) of tropical butterflies are comparatively inferior to those of temperate butterflies. Studies have shown that most swallowtails show a plastic trait due to the dimorphic coloration of the pupa (green and brown), while pink and green pupae are reported in Danaus chrysippus. In nature the environment is heterogeneous depending on the seasons, for example in one season there is a lot of green (grass, leaves, etc.) and in another season there is much less green. Since the color of the pupal substrate (the background) is a decisive factor for the survival of the immobile pupa, i.e. a green pupa can match the green background very well and remain invisible to predators, while brown coloring can be advantageous where green is lower or on substrates that are not green (e.g., brown tree trunk, soil, and dead brown leaf). Therefore, this seasonally varying color dimorphism and heterogeneous background helps them survive the critical stage of life. Although there is a good amount of research work on environmental factors that influence phenotypes, the genetic basis of plasticity remains less explored. In my thesis, I will address pupal color plasticity of tropical butterflies and how it is related to environmental factors such as different pupal substrate (grasses), as well as underlying genetics. Project 1. Genetic basis of pupal color plasticity in Mycalesis mineusOverview: Pupal color variation does not depend completely on environmental factors. Many studies have demonstrated the hereditary nature of this phenomenon in different swallowtail butterflies such as P. zelicaon, P. polyxenes and so on. The offspring produced by artificial selection of the selected line is more similar in color to its parents. Some studies have suggested that pupal color plasticity is inherited as a threshold trait. According to this model, the ability of a larva to produce green or brown pupae depends largely on an underlying phenotypic variable that is heritable. The larva that is very sensitive to green coloration may be less influenced by the environmental signals they inducethe brown color and become a green pupa and vice versa. However, along with sensitivity, the intensity of the inducing stimuli is also an important factor and usually varies depending on the population and species since the ecological conditions are not uniform in every location. A tropical Nymphalidae butterfly, Mycalesis mineus, shows pupal plasticity in the form of green and brown coloration. Studies have shown that under conditions of low relative humidity they produce pupae that are 20% brown and 80% green, while under conditions of higher relative humidity (i.e. 85% RH) they are almost exclusively green. Under tested laboratory conditions they also demonstrated that green pupae can form under all types of environmental cues and substrates, but the brown coloration of pupae is limited exclusively to particular conditions such as, they do not form on leaf substrate (exclusively on substrate outside the leaf, i.e. everywhere except the leaf substrate) and their number is significantly low at high relative humidity. My question: is the "sensitivity" of the larvae to produce a particular color heritable in the butterfly Mycalesis mineus? Hypothesis 1: If “sensitivity” is hereditary, then selected lines of green and brown pupae should produce a greater proportion of green and brown pupae respectively in subsequent generations. Hypothesis 2: Green pupae from the non-leaf substrate will tend to produce more green pupae on the non-leaf substrate in subsequent generations than green pupae from the foliar substrate. Methodology: I am conducting a series of artificial selection experiments. For my "Hypothesis 1", I use a larval growth chamber where the relative humidity is set at 60%, where we get a significant number of brown pupae along with the usual green pupae. The brown and green pupae will be separated. Adults that hatch from brown and green pupae will be raised separately. Each generation will be filtered for pupal color relative to lineage (green or brown). The experiment will have to last at least ten generations. Work done and work in progress: For “Hypothesis 1”, I initially started with 25 brown pupae. I obtained 15 adults (F0) and the larvae produced by them are much fewer and subsequently I did not obtain brown pupae but all green ones in the next generation (F1). I currently have a large number of eggs from the stock and want to repeat the experiment with a large sample. For “Hypothesis 2,” I began the experiment by placing a single wandering stage larva in an empty round cage. For the first round, I placed 6 larvae, each inside a round cage of similar height and structure and placed those cages inside the growth chamber with 60% relative humidity. I obtained 3 green pupae formed on the net of the cages and 3 other dead larvae. I will test this again with a large sample size. Project 2. Effect of different host plants on pupal color plasticity. Overview: The structure, color, smoothness, and texture of the pupal substrate have been shown to affect pupal color plasticity. Previous studies on pupal color polymorphism of Mycalesis mineus were conducted on maize plants. Since corn is not found in the wild and natural state for pupation, I want to check pupation substrate patterns for commonly available grasses. Some of the local herbs have already been identified by the morphology of the flower seeds (e.g. Eleusine indica, Paspalum scrobiculatum, Oplismenus sp., Axonopus sp.). Other herbs to use for comparison are Ragi and Wheat. Some of these grasses grow horizontally while others grow vertically. Their leaves and stems are different from each other in various aspects such as shape, structure, smoothness, etc. Even the 8.