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The balance between risk and benefit of exploiting resources drives life‐history evolution in organisms. Predators are naturally recognized as major drivers of the life‐history evolution of their prey. Although prey may also influence the life‐history evolution of their predators in the context of an evolutionary arms race, there is far more evidence of the role of predators than of prey.The goal of this study was to investigate the role of prey in life‐history evolution of predators using ladybird beetle predators of aphids and coccids. These particular ladybirds and their prey were chosen because literature shows that the pace of life of aphids is faster than that of coccids and this difference is reflected in the life histories of the ladybirds that specialize on feeding on aphids or coccids.Thirty‐four species of ladybird predators of aphids and eight of coccids belonging to five different tribes were collected and reared in the laboratory. The females were weighed as well as their eggs, and their reproductive investment estimated as the number of ovarioles. Phylogenetic relatedness was controlled for in the statistical analyses.Controlling for female mass revealed that ladybird predators of aphids lay bigger eggs than ladybird predators of coccids. This difference is not influenced by phylogenetic relatedness but only by the type of prey eaten. We suggest that ladybird predators of coccids lay smaller eggs because neonate larvae do not have to search, catch, and subdue prey. Both types of ladybirds have a similar reproductive investment relative to their body mass when phylogeny is controlled for.Recognizing the influence of prey on the life‐history evolution of predators is important for understanding food web dynamics. From an applied perspective, this fine evolutionary tuning of prey–predator relationships should be used to guide and increase the efficiency of biological control programs. [ABSTRACT FROM AUTHOR]

Changes in the weekly abundance in two natural populations of the Turkey-oak aphid, Myzocallis boerneri, from 1975 to 1992, were analyzed using autoregression methodology to determine the nature of dynamic processes. Seasonality forms the basis of aphid population dynamics. Analysis of time series of weekly and monthly data indicate statistically detectable seasonality in density changes. The monthly data statistically adjusted for seasonal effects (deseasoned) show that density fluctuates around a seasonally changing equilibrium value. Bulmer's test of density dependence applied to the seasonally adjusted monthly data reveals density dependence. The partial autocorrelation function (PACF) plots of smoothed deseasoned monthly density indicate time-lagged density-dependent processes operating between seasons and possibly on a shorter time scale of between 2 wk and 2 mo. The PACFs of smoothed deseasoned data provide statistical evidence for the existence of a 'see-saw' relationship between density in spring, autumn, and the following spring. Analysis of annual abundances calculated from the weekly data suggests that overall abundance in any year is influenced by abundance the previous year. The pattern of changes in abundance between years is most likely the consequence of the see-saw effect operating between seasons. It is argued that aphid population density is regulated by means of density-dependent processes acting within years, which is reflected in the year-to-year changes in overall abundance. Key words: aphids; autocorrelation; density dependence; Myzocallis boerneri; population dynamics; see-saw effect., INTRODUCTION Persistence of natural populations over long periods of time implies some form of regulation (Royama 1977, 1981). In recent years long-term census data on various insect and vertebrate species [...]

Employees from outsourcing company face a unique situation affiliated at both employing and client organizations while many literatures have confirmed that the level of employee's organizational commitment is highly associated with their job performance, This study will provide evidence that contingent employees' job performance in outsourcing should be considered by their commitments to both employing organization and the client organization (i.e., intercollege athletics marketing departments). Therefore, this study would provide better understanding of contingent employee's dual commitment to the organizations on their job performance and to confirm the causal relationship between organizational affective commitment and job performance. Two sets of six items on affective commitment were used to measure both organizational commitments toward to employing organization (i.e. marketing organization) and the client organization (i.e. intercollegiate athletics departments). Additionally, in-role behavior, organizational citizenship behavior benefiting an individual within the organization, and organizational citizenship behavior benefiting the organization were used to measure contingent employees' task performance in his/her specific working place. With total 121 contingent employees from a major outsourcing marketing company, this study firstly resulted that the commitment from the outsourcing company did not have a direct effect on employee' job performance. However, the employees' affective commitment to the client organization positively increases the level of their job performance. Second, the group low-affective commitments to both organizations had the minimized job performance while highaffective commitment to both groups had the maximized job performance. In addition, unbalanced-affective commitment resulted different level of job performances. Finally, this study contributes to the literature that it is necessary to examine employees' dual commitments to fully understand their dual employments. Additionally, this study would help marketing managers in both organizations to have better understanding of the wellbalanced dual commitments to maximize job performance in the temporary working environment because the employees' higher performance in outsourcing relationships are entered into organizational success. [ABSTRACT FROM AUTHOR]