Within a population of the butterfly Euphydryas editha that oviposits predominantly on two host species, heritable variation in postalighting oviposition preference was found. In a separate experiment, oviposition preference of adult females was found to be correlated with offspring performance (growth). There was a significant tendency for offspring to perform better on the host species that their female parent preferred. Analysis of the data showed that no single factor, neither maternal preference nor the host species on which the offspring were raised, accounted for any significant variation in larval performance. However, the effect of the interaction between host species and maternal preference on offspring performance was highly significant. These findings imply specialization in both oviposition preference and offspring performance by individuals within a single population. With present evidence, this preference-performance correlation is likely to be genetic. However, as in previous studies, other interpretations cannot be excluded.

Populations of the butterfly Euphydryas editha living within a 30 times 100-km region on the eastern slope of the Sierra Nevada range were compared for oviposition preference and ability of larvae to grow and survive on two host plants, Collinsia parviflora and Plantago lanceolata. Since its introduction approximately 100 years ago, P. lanceolata has been incorporated in the diet of E. editha in one of the study populations. The populations differed in oviposition preference; only the population that uses P. lanceolata contains some individuals that prefer P. lanceolata. Larvae from two populations, one using both P. lanceolata and C. parviflora, the other using only C. parviflora, were not found to differ in relative abilities to grow or survive on P. lanceolata. The potential for E. editha to use P. lanceolata appears in populations that have had no prior exposure to this plant, while oviposition preference for this plant has evolved in the population in which the plant now grows.

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We analyze the social and private learning at the symmetric equilibria of a queueing game with strategic experimentation. An infinite sequence of agents arrive at a server that processes them at an unknown rate. The number of agents served at each date is either a geometric random variable in the good state or zero in the bad state. The queue lengthens with each new arrival and shortens if the agents are served or choose to quit the queue. Agents can observe only the evolution of the queue after they arrive; they, therefore, solve a strategic experimentation problem when deciding how long to wait to learn about the probability of service. The agents, in addition, benefit from an informational externality by observing the length of the queue and the actions of other agents. They also incur a negative payoff externality, as those at the front of the queue delay the service of those at the back. We solve for the long-run equilibrium behavior of this queue and show there are typically mass exits from the queue, even if the server is in the good state.Cripps thanks the Cowles Foundation for its hospitality. Thomas gratefully acknowledges support from Deutsche Bank through IAS Princeton. We are grateful to V. Bhaskar, Max Stinchcombe, and Tom Wiseman for their comments. We thank four remarkably constructive referees for their comments and suggestions.Finally, in our equilibria, information can aggregate "in waves": in between informational cascades and ensuing herds, there will be periods of relative inactivity during which learning occurs gradually. Our model shares this feature with Bulow and Klemperer (1994), Toxvaerd (2008), and Murto and Välimäki (2011). The modelTime is discrete, doubly infinite, and indexed by τ ∈ Z. At each date τ, one new agent arrives at the queue. 7 The state of the server of our queue is either good or bad. The server is selected by nature once and for all at the outset of the game: nature selects the good server with probability μ ∈ (0 1). A bad server never produces service capacity, 8 and g τ = 0 for all τ, where g τ ∈ N 0 = {0 1 } denotes the service capacity produced by the server at date τ. Only a good server produces service. In this state g τ is an independent and identically distributed (i.i.d.) geometric 9 random variable with commonly known parameter α ∈ (0 1):Let n τ ∈ N 0 be the number of agents in the queue at the beginning of period τ. The queue discipline is first-come-first-served (FCFS), that is, agents are served in the order of the queue. At each date τ, we distinguish three consecutive stages: service (S), exit (E), and arrival (A). The S, E, and A stages proceed as follows.Service. If n τ > g τ , then the agents at the first g τ positions in line are served at the service stage of date τ and disappear from the queue. Each remaining agent observes this and advances by g τ positions. If n τ ≤ g τ , the entire queue is served and the excess service capacity, g τ − n τ , disappears. (It cannot be stored for use in subsequent periods.)Exit. This is the only stage of date τ...