In the cultivated cranberry (Vaccinium macrocarpon), reproductive stems produce 1-3 fruit even though they usually have 5-7 flowers in the spring. We undertook experiments to test the hypothesis that this was an adaptive life history strategy associated with reproductive effort rather than simply the result of insufficient pollination. We compared fruit production on naturally pollinated plants with those that were either manually pollinated or that were caged to exclude insects. Clearly, insects are necessary for the effective pollination of cranberry plants, but hand pollination of all flowers did not result in an increase in fruit number. Most of the upper flowers, which had significantly fewer ovules than did the lower flowers, aborted naturally soon after pollination. However, when the lower flower buds were removed, the upper flowers produced fruit. This suggests that the upper flowers may serve as a backup if the earlier blooming lower ones are lost early in the season. Furthermore, the late-blooming flowers may still contribute to the plant's reproductive success as visiting pollinators remove the pollen, which could serve to sire fruit on other plants. These results are discussed in the context of their possible evolutionary and proximate causes.

In a 3-yr study, we examined the pollinator guild and intersexual floral characteristics of the dioecious, perennial cloudberry (Rubus chamaemorus), which flowers in early spring. The findings contribute to our general understanding of pollination ecology at high latitudes and provide important information for the commercialization of cloudberry. Female flowers were smaller than males but provided more nectar, although this resource was low in both sexes. Insects from 43 families visited cloudberry flowers, yet four families (Apidae, Halictidae, Muscidae, Syrphidae) represented ca. 87% of all visitors observed. Introduction experiments revealed that apids and muscids are significantly poorer pollinators (based on fruit production) than halictids and syrphids, but when fruit mass or seed set was considered, there were no significant differences between families. Pollinator importance, a product of flower visitation frequency and seed set effectiveness, revealed that the dipterans were of paramount importance to the pollination of cloudberry. Furthermore, they are limited to cloudberry because their lapping mouthparts exclude them from accessing the nutritional rewards of competing Ericaceae flowers. While the total number of pollinator families observed suggest a generalist pollination system, if one considers the dominant pollinators (flies) as a functional group, then this insect-flower relationship could be considered a specialized one.

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Cloudberry (Rubus chamaemorus L.), a dioecious perennial plant of boreal circumpolar distribution, is greatly prized for its berries. We crossed two treatments, pollinator exclusion and supplementary hand‐pollination, to determine i) the relative importance of insects as pollinators, ii) if pollinator activity was a limiting factor for the sexual reproduction of the plant, and iii) the relative contribution of diurnal vs. nocturnal visitors to pollination. The activity of natural pollinators resulted in 97.5 and 88.5% fruit set, along with 76.7 and 62.5% seed set in 1998 and 1999, respectively. When insects were excluded, fruit‐set dropped significantly to 18.4 (1998) and 12.8% (1999) and seed‐set to 5.4 (1998) and 5.0% (1999) showing the importance of mid‐ and large‐sized insects as pollinators. Natural levels of insect activity were sufficient to ensure complete pollination in both years as supplementary hand‐pollination did not significantly increase either parameter in plots where pollinators had free access. Nocturnal insects may serve as pollinators (fruit‐set = 41%), although they were less effective than diurnal pollinators (fruit‐set = 93%).

Although the practice of giving examples is central to the effective teaching and learning of science, it has been the object of little educational research. The present study attends to this issue by systematically examining the exemplification practices of a university professor and his students' learning experiences during a biology lecture on animal behavior. It is reported that the science instructor provided students with a series of procedural, conceptual, and analytical examples. Each type of exemplification was characterized by a unique focus, form and degree of dialogism. These examples promoted student acquisition of specialized scientific language and engagement in varied types of argumentation: inductive reasoning by parallel cases, inductive reasoning by causation, inductive generalization, and deductive reasoning. Furthermore, students' experiences learning from examples were contingent upon their performance of parallel instructional activities such as text reading and note-taking. Based on these findings, we argue for the importance of promoting student development of exemplification literacy (the ability to critically assess the use of examples in scientific communication) and the need for science instructors to provide students with opportunities not only to learn science concepts through examples but also to learn about the nature of scientific exemplification itself. # 2016 Wiley Periodicals, Inc. J Res Sci Teach 53: 737-767, 2016 Keywords: science exemplification; learning science from examples; tertiary science instruction; inductive reasoning; deductive reasoning; active learning; dialog Giving examples is a practice central to the effective teaching of science. More than mere illustration of particular science concepts, exemplification is commonly used by science instructors for a variety of pedagogical ends, including developing and clarifying important concepts, explaining natural phenomena, giving supportive details to general and abstract ideas, engaging learners, and persuading students. D 'Alessandro, Sorensen, Homoelle, and Hodun (2014) use annotated examples (worked examples wherein key physical concepts are fleshed out and applied) as a means to foster student reading comprehension of science texts. Dong (2013) provides English language learners with culturally familiar examples (teaching examples adapted to students' specific cultural backgrounds) to promote conceptual understanding as well as language acquisition. These varied pedagogical forms and functions of exemplification show how Correspondence to: Alandeom