Animals’ personality traits are defined as consistent behavior tendencies and the function of them in life-history strategy and reproductive success has been given a lot of explanations in a large amount of research. However, the behavior consistency of individuals in different sexes, mating status and selection regimes is rarely mentioned. In this research, we were interested in personality traits and their consistency in inter-individuals and intra-individuals, and proposed that with the removal of fecundity selection males would evolve to be more female-like and decrease their locomotor activity, and copulation would change the physiological status of females and thus alter their levels of activity.   In the experiment, seed beetles (Callosobruchus maculatus) that were artificially selected in monogamy, polygamy and male-limited selection regimes were weighed, dropped in a designed arena and their behaviors were recorded with a camera for four minutes in the first day when they were newborn and virgin. In the next day, the virgin beetles were randomly paired to mate, weighed afterwards, and dropped in the arena again for videoing the same setting as yesterday. In data collection step, with these videos four behaviors types including walking, entering squares, time spent on roof and entering a new area were observed, scored and noted down. To process the data, we made correlation analysis and it was found that walking, entering square and a new area were positively correlated. After building the linear mixed effect models we found that sex together with mating significantly act in modifying beetles’ behaviors, males were more active than females but the difference was narrowed after mating, and copulation caused a significant increase in the level of locomotor activity in females. To our disappointment, selection regimes did not have any significant impact on locomotor activity. Our work gave an insight that copulation changed individuals’ behaviors more in females than in males and dimorphic expression of sex-biased genes differed due to mating effect.

All organisms live in environments that are variable across space and time. Variation in selection across these environments may lead to the evolution of generalist genotypes that express phenotypic plasticity, in which one genotype can alter their phenotype (e.g., morphology, behavior, physiology) to match changes in environmental conditions, so that they may survive across a range of environments. In many egg-laying organisms that lack parental care, choosing an oviposition site is critical. The egg is an immobile stage of an animal's life cycle and mothers must balance a complex set of risks in deciding where to place their eggs. Because many biotic and abiotic factors are sources of selection on offspring survival, there is an advantage for females to evolve strategies in oviposition site selection to improve survival. This dissertation focuses on phenotypic plasticity in an offspring protection strategy that is triggered by natural enemies. In the seed beetle Mimosestes amicus (Coleoptera: Chrysomelidae: Bruchinae), females lay eggs on the outside of seed pods of legume trees and beetle larvae bore into and develop in the limited and discrete tissue of the seed. While most eggs are laid singly, I documented that beetle females superimpose eggs atop each other ("egg stacking") in response to the presence of egg parasitoids or parasitized eggs. In my first chapter, I investigated whether egg stacking is a strategy for protecting eggs from parasitism. In my second chapter, I examined female responses to variation in the number and dispersion of parasitized eggs on seed pods. Lastly, I investigated whether the intensity of stacking was affected by egg limitation (the risk of depleting her eggs before utilizing all hosts) or time limitation (losing reproductive ability or dying before laying all of her eggs). This study is unique in that it extends life history theory on egg and time costs to explain variation in egg protection behavior. The insights gained from this dissertation provide a foundation upon which we can examine how interactions among trophic levels impact the behavioral decisions made by insects that allow them to increase offspring survival.

Seminal fluid proteins (SFPs) have been shown to affect the physiology,behaviour and immune responses of mated females in some species. Thisopen window for manipulation of female’s fitness allows the possibility forcomplex evolutionary dynamics between the SFPs and proteins of femalesthat would counter the effects of the former, the female reproductive proteins (FRPs). Also, the bean beetles of the Bruchinae subfamily are pests to pre-ferred species of plant hosts. The hosts have a great variety of secondary defensive metabolites between them and to detoxify those compounds, each beetle species is expected to have a well adapted arsenal of digestive proteinsfor a specific host. I carried out a comparative study with four species of bean beetles with the aim to identify patterns of selection in the proteins mentioned. Expression data for one of those species, Callosobruchus maculatus, has allowed to identify its SFPs, FRPs and digestive proteins and with orthology inference I identified their orthologues in the other three species. Then I estimated theratio of non-synonymous to synonymous substitution rates (ω) for each protein by using codeML of the PAML package and used them as a proxy for estimating selection. FRPs had about the same ω values as conserved genes found across the Arthropod phylum, while the SFPs and digestive proteins hadhigher ω values, indicating more relaxed purifying selection. I also performed tests of positive selection and have identified 92 digestive proteins, 9 FRPs and 26 SFPs as potential targets for future functional work. Finally, I examined the scenario of co-evolution between SFPs and FRPs because of direct interaction. By correlating branch-specific ω values for each possible pairs of proteins I found that SFPs are associated on average more with FRPs than with digestive or conserved genes, as expected. The same was true for the FRPs. Also I examined the possibility of factors contributing to the association such as expression levels, sex-biased expression and protein function. Using linear regression models I found that expression levels and proteinfunction do predict in some degree the ω estimates and could thus also affectthe correlations examined. High gene expression levels reduce the overall ωvalues of genes, also known as E-R anticorrelation. Sex-biased expression does not affect the overall ω values, but does affect the intensity of the E-R anticorrelation, with it being less prominent in male-biased genes and more prominent towards female-biased genes.