The cuckoo bee genus Kelita : its systematics, biology, and larvae. American Museum novitates ; no. 2631

24 p. : ill., map ; 26 cm.Includes bibliographical references (p. 23-24)."Three new species (toroi, penai, and tuberculata) are added to the Chilean cuckoo bee genus Kelita heretofore thought to be monotypic (type species: chilensis Friese). Presented are descriptions of adults of all taxa, comparative illustrations of the male genitalia and other taxonomic features, a key to species, and a distribution map of the species. The anatomical parts of the complicated male genitalia are homologized. An attempt to analyze the phylogenetic relationships of Kelita to other Nomadini indicates that it is most closely related to Paranomada, Triopasites, Melanomada, Brachynomada, and Hesperonomada. Kelita tuberculata and chilensis are reported to be parasitic on small panurgines. Details of adult and larval activity and larval development indicate that the biology of Kelita is not substantially different from that of other Nomadini. Taxonomic descriptions of the first and last larval instars of tuberculata reveal that these stages are similar in most respects to those of other Nomadinae although the mature larva, unlike the larvae of most members of the subfamily, bears paired dorsal body tubercles"--P. [1]

Effects of exotic plant invasions on soil nutrient cycling processes.

ABSTRACT Although it is generally acknowledged that invasions by exotic plant species represent a major threat to biodiversity and ecosystem stability, little attention has been paid to the potential impacts of these invasions on nutrient cycling processes in the soil. The literature on plant-soil interactions strongly suggests that the introduction of a new plant species, such as an invasive exotic, has the potential to change many components of the carbon (C), nitrogen (N), water, and other cycles of an ecosystem. I have reviewed studies that compare pool sizes and flux rates of the major nutrient cycles in invaded and noninvaded systems for invasions of 56 species. The available data suggest that invasive plant species frequently increase biomass and net primary production, increase N availability, alter N fixation rates, and produce litter with higher decomposition rates than co-occurring natives. However, the opposite patterns also occur, and patterns of difference between exotics and native species show no trends in some other components of nutrient cycles (for example, the size of soil pools of C and N). In some cases, a given species has different effects at different sites, suggesting that the composition of the invaded community and/or environmental factors such as soil type may determine the direction and magnitude of ecosystem-level impacts. Exotic plants alter soil nutrient dynamics by differing from native species in biomass and productivity, tissue chemistry, plant morphology, and phenology. Future research is needed to (a) experimentally test the patterns suggested by this data set; (b) examine fluxes and pools for which few data are available, including whole-site budgets; and (c) determine the magnitude of the difference in plant characteristics and in plant dominance within a community that is needed to alter ecosystem processes. Such research should be an integral component of the evaluation of the impacts of invasive species