Whitney R. Harris World Ecology Center

Early field work on naked mole-rats, Heterocephalus glaber, suggested that small colonies are rare and that colonies can only form by fissioning of existing colonies. Many researchers expected that this would result in extreme inbreeding and high relatedness within colonies and would thus explain the evolution of eusociality in naked mole-rats. Here I report evidence of dispersers and outbreeding in colonies of wild naked mole-rats that suggests that inbreeding is not the system of mating for this species and that outbreeding is probably frequent. Wild dispersers have the same morphology as was reported for dispersers in laboratory colonies. Low levels of genetic variation in previous molecular genetic studies of naked mole-rats probably result from the viscous population structure typical of fossorial rodents.

Among mammals generally and rodents particularly mean litter sizes usually are about onehalf the number of mammae, and maximum litter sizes approximate mammary numbers. Naked mole-rats (Heterocephalus glaber: Bathyergidae) are exceptions to both generalizations. Field-caught litters averaged 11.3 young 6.2 SD (n = 82), and captive-born litters averaged 11.4 5.6 young (n = 190). Similarly, numbers of mammae on breeding females averaged 11.6 . 1.1 (n = 43) in the field and 11.5 2.0 (n = 29) in captivity.

We compared survival of free-living naked mole-rats, Heterocephalus glaber, marked by toe-clipping and implantable transponder chips. Although survival was marginally higher for toe-clipped animals than for those with transponder chips in five of six colonies, no significant differences were found between the two marking techniques. Comparison of the costs and benefits of the two marking techniques suggests that toe-clipping is preferable for marking small fossorial mammals in remote areas.

Environmental heterogeneity resulting from human-modified landscapes can increase intraspecific trait variation. However, less known is whether such phenotypic variation is driven by plastic or adaptive responses to local environments. Here, we study five bumble bee (Apidae: Bombus) species across an urban gradient in the greater Saint Louis, Missouri region in the North American Midwest and ask: (1) Can urban environments induce intraspecific spatial structuring of body size, an ecologically consequential functional trait? And, if so, (2) is this body size structure the result of plasticity or adaptation? We additionally estimate genetic diversity, inbreeding, and colony density of these species-three factors that affect extinction risk. Using ≥ 10 polymorphic microsatellite loci per species and measurements of body size, we find that two of these species (Bombus impatiens, Bombus pensylvanicus) exhibit body size clines across the urban gradient, despite a lack of population genetic structure. We also reaffirm reports of low genetic diversity in B. pensylvanicus and find evidence that Bombus griseocollis, a species thought to be thriving in North America, is inbred in the greater Saint Louis region. Collectively, our results have implications for conservation in urban environments and suggest that plasticity can cause phenotypic clines across human-modified landscapes.

however the effect of this parasite on passerines has not been studied. We report on these findings because parasites can have large effects on individual host populations and on the ecology of a community, but may go undetected.

Livebearing fishes in the family Poeciliidae have been essential to testing life history theory. These species are remarkable because males internally inseminate females, and females give birth to free-swimming young, making these fishes amenable to investigating the evolution of a variety of life history traits, including the timing and nature of maternal reproductive investment, timing of maturity, strategies for maternal provisioning of embryos, and several other classic life history traits. However, researchers vary in the methods that they use to measure these traits, making it difficult to compare findings across studies. Here, I present a standardized approach to studying life history traits in livebearing fishes. I describe methods for preserving samples in the field, for collecting data on a standard set of life history traits, and for processing data in ways that will allow comparisons among studies. I highlight different options in preservation techniques and in data collection that are dependent on the specific questions being addressed. Finally, I argue for a standard approach moving forward to make it possible to complete large-scale comparative studies to reveal how life history traits have evolved in this important model system.

Environmental effects on learning are well known, such as cognition that is mediated by nutritional consumption. Less known is how seasonally variable environments affect phenological trajectories of learning. Here, we test the hypothesis that nutritional availability affects seasonal trajectories of population-level learning in species with developmentally plastic cognition. We test this in bumble bees (Apidae: Bombus), a clade of eusocial insects that produce individuals at different time points across their reproductive season and exhibit organ developmental plasticity in response to nutritional consumption. To accomplish this, we develop a theoretical model that simulates learning development across a reproductive season for a colony parameterized with observed life history data. Our model finds two qualitative seasonal trajectories of learning: (1) an increase in learning across the season and (2) no change in learning across the season. We also find these two qualitative trajectories revealed by empirical learning data; the proportion of workers successfully completing a learning test increases across a season for two bumble bee species (Bombus auricomus, Bombus pensylvanicus) but does not change for another three (Bombus bimaculatus, Bombus griseocollis, Bombus impatiens). This study supports the novel consideration that resources affect seasonal trajectories of population-level learning in species with developmentally plastic cognition.

To date, most studies on the management of invasive species have been done in nature reserves or national parks. Few published studies demonstrate how scientists and local communities might collaborate to develop science-based management programs in private forests. We present an example of such collaboration. The Congregational Summer Assembly (CSA) is a mixture of common and privately owned lots within old-growth beech-maple forest in Lower Michigan. The community is trying to conserve the forest and, thus, is interested in ecological variables that should be considered when designing a long-term ecosystem based management plan.In this base-line study we developed methods for volunteer-scientist teams to monitor 1) the abundance of established invasive species, 2) native species abundance, 3) local environmental conditions and 4) impacts of anthropogenic disturbances on the forest community composition. In July 2009 we constructed 30 permanent plots (20 m x 20 m), within which we counted and identified to species adult and juvenile trees. We counted and identified to species herbaceous plants and tree seedlings in five 2 m x 2 m quadrats nested within each plot. We measured environmental variables (% canopy, % bare soil, % woody debris and distance from road or building) in each quadrat.The CSA forest is under stress from anthropogenic disturbance and invasive species. Long-term monitoring of forest community composition could augment the efficacy of efforts to control invasive species at the CSA. The floristic quality index value (FQI), a unitless calculation of species per area, calculated for the CSA is 30 (based on 1.2-ha). FQI values calculated for the CSA in 2009 can be compared with those measured in later years to evaluate whether the plant community composition improves over time with management.Of 69 species found in plots, 9 were non-native, 3 of which were invasive. Invasive garlic mustard (Alliaria petiolata) and myrtle (Vinca minor) were the dominant understory species. Garlic mustard remains the priority for eradication efforts. With the exception of garlic mustard no invasive species were found in plots further than 20 m from roads and buildings. A volunteer-based monitoring program for early detection of “founder” populations of invasive species could be effective in controlling invasive species. The CSA acquired funds for the summer of 2010 to build demonstration plots to educate the community on invasive species removal. This study provides a template for scientists to collaborate with private communities interested in science-based management programs that promote conservation.

Abstract To date, most studies on the management of invasive species have been done in nature reserves or national parks. Few published studies demonstrate how scientists and local communities might collaborate to develop science-based management programs in private forests. We present an example of such collaboration. The Congregational Summer Assembly (CSA) is a mixture of common and privately owned lots within old-growth beech-maple forest in Lower Michigan. The community is trying to conserve the forest and, thus, is interested in ecological variables that should be considered when designing a long-term ecosystem based management plan.In this base-line study we developed methods for volunteer-scientist teams to monitor 1) the abundance of established invasive species, 2) native species abundance, 3) local environmental conditions and 4) impacts of anthropogenic disturbances on the forest community composition. In July 2009 we constructed 30 permanent plots (20 m x 20 m), within which we counted and identified to species adult and juvenile trees. We counted and identified to species herbaceous plants and tree seedlings in five 2 m x 2 m quadrats nested within each plot. We measured environmental variables (% canopy, % bare soil, % woody debris and distance from road or building) in each quadrat.The CSA forest is under stress from anthropogenic disturbance and invasive species. Long-term monitoring of forest community composition could augment the efficacy of efforts to control invasive species at the CSA. The floristic quality index value (FQI), a unitless calculation of species per area, calculated for the CSA is 30 (based on 1.2-ha). FQI values calculated for the CSA in 2009 can be compared with those measured in later years to evaluate whether the plant community composition improves over time with management.Of 69 species found in plots, 9 were non-native, 3 of which were invasive. Invasive garlic mustard (Alliaria petiolata) and myrtle (Vinca minor) were the dominant understory species. Garlic mustard remains the priority for eradication efforts. With the exception of garlic mustard no invasive species were found in plots further than 20 m from roads and buildings. A volunteer-based monitoring program for early detection of “founder” populations of invasive species could be effective in controlling invasive species. The CSA acquired funds for the summer of 2010 to build demonstration plots to educate the community on invasive species removal. This study provides a template for scientists to collaborate with private communities interested in science-based management programs that promote conservation.

In the decade since the last edition of this book much has changed. The world’s human population increased by almost 1 billion people, worldwide 13 million hectares of forests were cleared, the CO2 concentration of our atmosphere increased from 0.036% to 0.039%, oceans have become more acidic and sea levels have risen. These changes threaten tropical ecosystems in many ways and scientific interest in the ecology of this part of the world has increased significantly as a result. Over 45% of the references listed in this edition were published since the first edition appeared and, through these and many other studies, our understanding of tropical ecosystems has significantly improved. However, many gaps and challenges remain.