AbstractThe Diptera are the second most important order among flower-visiting (anthophilous) and flower-pollinating insects worldwide. Their taxonomic diversity ranges from Nematocera to Brachycera, including most families within the suborders. Especially important are Syrphidae, Bombyliidae, and Mu

AbstractPortions of the labyrinth or villi of placentas from late pregnancy from nine species in four orders of mammals were examined with the electron microscope. Pronounced patterns of layering of the trophoblast were found in these placentas which were all of the hemochorial type. The laboratory

An allocation framework is developed, which provides a template for conceptualizing the interactions among resource acquisition, allocation and life- history traits, and fosters a mechanistic understanding of life-history patterns, and the beginning of an understanding of the processes underlying th

Selfing by geitonogamy incurs a fitness cost of reduced pollen export, and recent reports show that seed set can suffer as well, even in self-incompatible species.

SignificanceWe present a conceptual framework for testing theories for the latitudinal gradient of species richness in terms of variation in functional diversity at the alpha, beta, and gamma scales. We compared ecological community theory with large-scale observational data of tree species richness

Despite broad consensus on the power of experiments, correlational studies are still important in ecology, and may become more so as spatial studies proliferate. Conventional correlation analysis, however, (1) fundamentally conflicts with the basic ecological concept of limiting factors, and (2) ign

The effects that below‐freezing temperature (frost) can have at times of year when it is unusual are an interesting ecological phenomenon that has received little attention. The physiological consequence of formation of ice crystals in plant tissue is often death of the plants, or at least of sensit

M ore than a century ago, Darwin (lg59) observed that number of bumblebees in any district depends in a great measure upon the number of fieldmice, which destroy their combs and nests ... che number of mice is largely Jependent, as everyone knows, on the number of cats .. .it is quite credible that

Paul J. CaraDonna,1,2,3,4* Whether species interactions are static or change over time has wide-reaching ecological and evo- William K. Petry,1,5,6 lutionary consequences. However, species interaction networks are typically constructed from tem- Ross M. Brennan,1,7 porally aggregated interaction dat

Using experimental manipulations, we examined pollen and resource limitations to seed production and their interaction in a natural population of a monocarpic plant, Ipomopsis aggregata. Our design cross two factors, pollen level (hand—pollinated or control) and resource level (water added, water an

A system comprising 2 species of bumblebess (Bombus appositus and Bombus flavifrons) and 2 species of flowers (Delphinium barbeyi and Aconitum columbianum) in Gothic, Colorado, USA, was manipulated to determine whether resource utilization by each bumblebee species was influenced by the presence of

Aging, often considered a result of random cellular damage, can be accurately estimated using DNA methylation profiles, the foundation of pan-tissue epigenetic clocks. Here, we demonstrate the development of universal pan-mammalian clocks, using 11,754 methylation arrays from our Mammalian Methylati

Understanding the functional impacts of pollinator species losses on plant populations is critical given ongoing pollinator declines. Simulation models of pollination networks suggest that plant communities will be resilient to losing many or even most of the pollinator species in an ecosystem. Thes

AbstractComparative analyses of survival senescence by using life tables have identified generalizations including the observation that mammals senesce faster than similar‐sized birds. These generalizations have been challenged because of limitations of life‐table approaches and the growing apprecia

Results of laboratory experiments suggest that a water‐soluble factor released into the environment by the predacious phantom midge larva Chaoborus americanus (Diptera: Chaoboridae) causes embryos of the waterflea Daphnia pulex Leydig 1860 emend. Richard 1896 (Crustacea: Cladocera) to develop into a

Analysis of life-history traits of 18 species of burrowing sciurids indicates that reproductive effort is determined by body-size energetics, and sociality in these species may have evolved through retention of daughters within the maternal home range as a means of continuing reproductive investment

Nectar robbers are birds, insects, or other flower visitors that remove nectar from flowers through a hole pierced or bitten in the corolla. This paper is a review of the effects of nectar robbers on pollinators, pollination, and fitness of the plants they rob. Charles Darwin assumed that nectar rob

The use of path analysis has grown rapidly in recent years, yet few studies employ recent advances in the field of structural equation modelling (SEM). Here I illustrate the capabilities of SEM for path analyses, using data from a study of hummingbird pollination. The main drawback to conventional p

Several recent studies have shown that males and females in some populations of dioecious plants are spatially segregated with respect to an environmental gradient. The inference is often made that such spatial segregation of the sexes (SSS) is favored by selection because it reduces competition bet

Data are given on the composition, temperature, pressure, and density of the hydrothermal fluids present in the central Cu-Mo core of the deposit at Bingham, Utah, and in its related but not necessarily coeval peripheral Pb-Zn deposits. These data are based on a study of primary and secondary fluid