There is a common and long‐standing belief that tropical butterflies are more striking in their coloration than those of cooler climates. It has been suggested that this is due to more intense biotic selection or mate selection in the tropics. We tested whether there were differences in coloration by examining the dorsal surface color properties of male butterflies from three regions of the western hemisphere: the Jatun‐Satcha Reserve in lowland Ecuador (tropical), the state of Florida, USA (subtropical) and the state of Maine, USA (cool temperate). We digitally photographed the dorsal wing and body surface of male butterfly specimens from Maine, Florida, and Ecuador. For each photograph, we analyzed the mean and variation for the color‐parameters that are thought to be related to colorfulness; namely Hue, saturation and intensity. Overall, the Ecuadorian sample exhibited more varied intensity, saturation, and Hue compared to the other regions. These results suggest a more complex assemblage of colors and patterns regionally and on a butterfly‐by‐butterfly basis in the tropics. The greater complexity of colors within each butterfly in our Ecuadorian sample suggests that tropical butterflies are indeed more ‘colorful’, at least by some measures. Possible reasons for this include stronger predation pressure selecting for aposematism, greater species diversity selecting for camouflage or warning coloration against potential predators, and easier recognition of potential mates in a species rich environment.

The aquarium trade has been shown to be a source for introductions of nonnative aquatic macrophyte species. Improvements are needed in identification, labeling, and retailer awareness of banned aquatic plants. In the state of Connecticut, United States, 20 nonnative macrophytes are banned from sale by state statute. At least 13 of these species are already established in the state's lakes, while the remainder are either present in near-shore wetlands or absent but thought to be capable of naturalizing. We documented the sale of banned plants in the Connecticut aquarium trade by visiting 23 retailers in 2008 and 47 retailers in 2010. Plants that resembled Connecticut's banned species were purchased and identified using standard morphological techniques. In 2010, we also employed DNA sequencing to aid in plant identification. We found that nearly 30% of stores sold banned aquatic plants including Cabomba caroliniana, Egeria densa, Myriophyllum aquaticum, and Myriophyllum heterophyllum. Cabomba caroliniana represented more than half of the banned species being sold; it was found in 17% of the stores in 2008 and 19% of the stores in 2010. Egeria densa was mislabeled 50% of the time as Egeria najas or Anacharis najas; it was sold in 11% of the stores in 2008 and 17% of the stores in 2010. In 2010, Myriophyllum specimens from 6 stores were unidentifiable using morphological characteristics. Using these techniques, one of the specimens was identified as Myriophyllum heterophyllum. Of the 29 chain stores surveyed, 7% sold banned species compared to 56% of the 27 independent stores.

No abstract

No abstract

The relative influences of fine and landscape scale factors on the structure of lentic plant assemblages. Lake Reserv Manage. 32:116-131. The process of plant community assembly has long been a topic of debate among ecologists. Aquatic plant assemblages and their structure may be the result of a series of abiotic and biotic filters that include transport (i.e., physical movement of species), water chemistry, sediment chemistry, basin structure, and competitive interactions. The influences of transport and water chemistry have been well investigated, but many questions persist about the interrelationships among water and sediment variables, including their combined influences on the structure of the aquatic plant assemblage. To understand how these abiotic conditions interact, we sampled 750 points in 30 lakes. Using these data, a split canonical correspondence design was used to evaluate the relative influences of regional and fine-scale conditions in structuring the plant assemblage. Additionally, multiple logistic regressions were employed to determine the individual species' abiotic preferences. The results suggest that the plant assemblage structure is principally determined by the lake-sediment characteristics. Sediment variables explained 28% of the total species-data variance and water chemistry accounted for 9% (total variance explained = 46%; 9% due to intercorrelation of water/sediment characteristics). There were also strong species-environmental relationships; nonnative species showed distinct correlations with sediment pH and lake water conductivity, which may be useful in lake management initiatives such as risk assessment and nonnative species monitoring. Finally, and as expected, the Shannon diversity index was strongly related to depth and light. Assembly theory views plant communities as aggregates of species present in an area due to their relationships with environmental conditions, successful recruitment, and competitive ability (Weiher and Keddy 1995, Wilson 1999). Plant assemblage structure and the inherent oscillations of species vary with abiotic conditions and disturbances but may result in an assemblage composed of species best suited to the local environment (Weiher and Keddy 1995, Wilson 1999). In this study, we examined the composition of rooted aquatic plant assemblages and the associated abiotic filters to better understand the mechanisms that structure these assemblages in lentic systems. In 2009, Capers et al. (2009a) examined the influences of lake location, water chemistry conditions, and the dispersal abilities of species on the structure of these