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Floral scents act as long-distance signals to attract pollinators, but volatiles emitted from the vegetation and neighboring plant community may modify this mutualistic communication system. What impact does the olfactory background have on pollination systems and their evolution? We consider recent behavioral studies that address the context of when and where volatile backgrounds influence a pollinator's perception of floral blends. In parallel, we review neurophysiological studies that show the importance of blend composition and background in modifying the representation of floral blends in the pollinator brain, as well as experience-dependent plasticity in increasing the representation of a rewarding odor. Here, we suggest that the efficacy of the floral blend in different environments may be an important selective force shaping differences in pollinator olfactory receptor expression and underlying neural mechanisms that mediate flower visitation and plant reproductive isolation.

Circadian patterns of activity are considered ubiquitous and adaptive, and are often invoked as a mechanism for temporal niche partitioning. Yet, comparisons of rhythmic behavior in related animal species are uncommon. This is particularly true of Lepidoptera (butterflies and moths), in which studies of whole-animal patterns of behavior are far outweighed by examinations of tissue-specific molecular clocks. Here, we used a comparative approach to examine the circadian patterns of flight behavior in Manduca sexta and Hyles lineata, two distantly related species of hawkmoth (Sphingidae). By filming isolated, individual animals we were able to examine rhythmic locomotor (flight) activity at the species level as well as at the level of the individual sexes, and in the absence of interference from social interaction. Our results confirm classic descriptions of strictly nocturnal behavior in M. sexta and demonstrate a dramatically different activity pattern in H. lineata. Furthermore, we show distinct species and sex-specific differences in the maintenance of the endogenous rhythm under conditions of constant darkness. In both species, female activity peaks in advance of males, whereas male activity coincides with periods of female sexual receptivity. This suggests a role for circadian patterns of locomotor activity in synchronizing periods of sexual receptivity between the sexes.

Herbivory is viewed as a major driver of plant evolution and the most important energy pathway from plants to higher trophic levels. Therefore, understanding patterns of herbivory on plants remains a key focus in evolution and ecology. The evolutionary impacts of leaf herbivory include altering plant fitness, local adaptation, the evolution of defenses, and the diversification of plants as well as natural enemies. Leaf herbivory also impacts ecological processes such as plant productivity, community composition, and ecosystem nutrient cycling. Understanding the impact of herbivory on these ecological and evolutionary processes requires species-specific, as opposed to community-level, measures of herbivory. In addition, species-specific data enables the use of modern comparative methods to account for phylogenetic non-independence. Although hundreds of studies have measured natural rates of leaf consumption, we are unaware of any accessible compilation of these data. We created such a data set to provide the raw data needed to test general hypotheses relating to plant–herbivore interactions and to test the influence of biotic and abiotic factors on herbivory rates across large spatial scales. A large repository will make this endeavor more efficient and robust. In total, we compiled 2641 population-level measures for either annual or daily rates of leaf herbivory across 1145 species of vascular plants collected from 189 studies. All damage measures represent natural occurrences of herbivory that span numerous angiosperm, gymnosperm, and fern species. To enable researchers to explore the causes of variation in herbivory and how these might interact, we added information about the study sites including: geolocation, climate classification, habitat descriptions (e.g., seashore, grassland, forest, agricultural fields), and plant trait information concerning growth form and duration (e.g., annual vs. perennial). We also included extensive details of the methodology used to measure leaf damage, including seasons and months of sampling, age of leaves, and the method used to estimate percentage area missing. We anticipate that these data will make it possible to test important hypotheses in the plant–herbivore literature, including the plant apparency hypothesis, the latitudinal-herbivory defense hypothesis, the resource availability hypothesis, and the macroevolutionary escalation of defense hypothesis.