Understanding variation in resource specialization is important for progress on issues that include coevolution, community assembly, ecosystem processes, and the latitudinal gradient of species richness. Herbivorous insects are useful models for studying resource specialization, and the interaction between plants and herbivorous insects is one of the most common and consequential ecological associations on the planet. However, uncertainty persists regarding fundamental features of herbivore diet breadth, including its relationship to latitude and plant species richness. Here, we use a global dataset to investigate host range for over 7,500 insect herbivore species covering a wide taxonomic breadth and interacting with more than 2,000 species of plants in 165 families. We ask whether relatively specialized and generalized herbivores represent a dichotomy rather than a continuum from few to many host families and species attacked and whether diet breadth changes with increasing plant species richness toward the tropics. Across geographic regions and taxonomic subsets of the data, we find that the distribution of diet breadth is fit well by a discrete, truncated Pareto power law characterized by the predominance of specialized herbivores and a long, thin tail of more generalized species. Both the taxonomic and phylogenetic distributions of diet breadth shift globally with latitude, consistent with a higher frequency of specialized insects in tropical regions. We also find that more diverse lineages of plants support assemblages of relatively more specialized herbivores and that the global distribution of plant diversity contributes to but does not fully explain the latitudinal gradient in insect herbivore specialization.

Sixteen years ago, a schoolteacher from New Jersey collected a caterpillar in a Costa Rican rainforest. When a parasitoid emerged several days later, it became the first data point of a long-term volunteer–mediated study on tritrophic interactions across the Americas. The teacher was an Earthwatch Institute scientist and the project an ongoing ecological investigation of caterpillars, host plants, and the wasps and flies (parasitoids) that kill them (Fig. 1). Over the course of 16 years, 1,200 volunteers have contributed to the project, including adult and youth citizen scientists from Earthwatch, teachers, and a number of other volunteers who have offered their time for months or years. With the help of these citizen scientists, we have created a robust data set on plant-herbivore-enemy interactions in order to test specific hypotheses about how the diversity of trophic interactions varies across major environmental gradients. Well over half the described organisms in the world are involved in plant-insect-enemy interactions, and research on these diverse interactions has provided the basis of our understanding of fundamental issues in ecology and evolutionary biology. Nevertheless, most biodiversity studies still rely heavily on static species lists, and prominent theories of diversity do not yet include quantification or discussion of the interaction diversity that shapes ecosystems. This interaction diversity approach to ecological research contributes to all major theoretical and applied issues in biodiversity research, including the latitudinal diversity gradient, neutral theory, diversity-stability relationships, biodiversity and ecosystem function, specialization, latitudinal and elevational range size, and effects of climate change on biodiversity. In addition to the focus on basic ecology and natural history, the project contributes to systematics of our study organisms and prioritizes work with teachers, students, local communities, and the general public to increase awareness of the importance of biodiversity.

through the accumulated work of others, and scanned the Internet for photographic evidence of the tallow leaf roller. We also invited a widespread community of entomology enthusiasts to actively assist us by contributing specimens or photographic vouchers. A single photographic record, if reliable, can expand the known range of our target species by thousands of square kilometers, and take the place of an expensive and lengthy series of collecting trips. Also, if we know the date of the photo, it can serve as a definitive temporal reference point when trying to trace the history of an expanding population (much like a dated fossil). The acquisition of such data is a necessary first step in determining the population dynamics and potential for future growth of this specialist herbivore, an effort which is of particular importance in the context of the undesirable, wildly proliferating tree upon which it feeds.

Citizen science is becoming in an integral part of entomological research and education. Large-scale, long-term research projects, vital to the study of ecological interactions, are often prohibitively expensive and difficult to manage without input from citizen scientists (Silvertown 2009). For educators and students, involvement in entomology research can provide a valuable educational opportunity by incorporating professional development for teachers and a hands-on, social learning environment (Krasny 2005). Considering the importance placed on the educational benefits of outreach efforts in scientific research, it is surprising that little is known about its actual impact on education. Although participation in citizen science research has been correlated with communication that reflects scientific thought processes, it is unclear whether this change was a result of the participation itself, or the result of having a forum for engaging these thought processes (Trumball et al. 2000). For example, in a study of citizen participants in an avian study, it was clear that volunteers had increased their basic knowledge about bird biology, but showed no significant change in their actual understanding of scientific processes or in their attitudes toward the environment and science in general (Brossard et al. 2005). However, efforts to explicate scientific issues and address misunderstandings about scientific processes by the professionals leading citizen science-based research projects could significantly enhance the educational impact of volunteer–scientist interactions (Trumball et al. 2000; Brossard et al. 2005). The highly competitive funding environment in the sciences often means that trained professionals, such as research assistants, graduate students, and postdoctoral fellows, are not available to assist with the field and laboratory work that is necessary to address hypotheses at appropriate temporal and spatial scales (Cohn 2008). Volunteer researchers can fill this gap, if protocols are straightforward and the necessary training is not overly complex (Cohn 2008; Silvertown 2009). A multitude of ecological studies have utilized citizen scientists to achieve large amounts of publishable data (see articles by Dyer et al., Losey et al., and Oberhauser in this issue). Furthermore, public funding agencies accountable to citizen taxpayers are increasingly interested in supporting research with a broader educational impact (Cohn 2008; Silvertown 2009). Therefore, the benefits of incorporating volunteer efforts, especially those of teachers and students, into entomological studies may reach beyond the databases compiled by these efforts by making research projects more appealing to the funding agencies that support them. The benefits of citizen scientist projects are multifaceted and far-reaching. Ideally, the interaction should benefit both the citizens (e.g., education) and the professional scientists (e.g., quality data) participating in the project (Silvertown 2009). In this article, we will discuss how citizen scientist participation in our study has impacted the educational goals of teacher participants and had sustained effects on the students they teach. We will also illustrate an example of how student volunteers can demonstrate progressive mastery of scientific processes while taking part in a research project. Additionally, we will highlight some of the benefits our research team has derived from this interaction. Considering the relatively small effort invested in training them, we argue that incorporating teacher and student volunteers into scientific research can yield cascading effects on science education.

The New World species of the brachypterous wasp genus Olixon Cameron are revised and five species are recognized: Olixon atlanticum Fernandez & Sarmiento-M., O. banksii (Brues), O. bicolor Roig Alsina & Martinez, O. melinsula sp. n. and O. testaceum Cameron. The new species and the previously unknown female of O. bicolor are described. An identification key and a distribution map for the New World Olixon are provided. The genus Olixon is more widely distributed throughout the New World than previously thought and here newly recorded from Belize, Bolivia, Canada, Ecuador, Guatemala, Paraguay, Peru, Suriname, Trinidad and Tobago and Venezuela. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)