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Butterflies in the family Lycaenidac are often the focus of conservation efforts. However, our understanding of lycaenid population dynamics has been limited to relatively few examples of long-term monitoring data that have been reported. Here, factors associated with population regulation are investigated using a complete record of a single population of the silvery blue, Glaucopsyche lygdamus Doubleday (Lepidoptera: Lycaenidae). Adults of G. lygdamus were first observed in an annual grassland near Davis, California, in 1982 and were last seen in 2003. Relationships between inter-annual variation in abundance and climatic variables were examined, accounting for density dependent effects. Significant effects of both negative density dependence and climatic variation were detected, particularly precipitation and temperature during winter months. Variation in precipitation, the strongest predictor of abundance, was associated directly and positively with butterfly abundance in the same year. Winter temperatures had a negative effect in the same year, but had a lagged, positive effect on abundance in the subsequent year. Mechanistic hypotheses are posed that include climatic effects mediated through both larval and adult plant resources.

Climate change and habitat destruction have been linked to global declines in vertebrate biodiversity, including mammals, amphibians, birds, and fishes. However, invertebrates make up the vast majority of global species richness, and the combined effects of climate change and land use on invertebrates remain poorly understood. Here we present 35 years of data on 159 species of butterflies from 10 sites along an elevational gradient spanning 0-2,775 m in a biodiversity hotspot, the Sierra Nevada Mountains of Northern California. Species richness has declined at half of the sites, with the most severe reductions at the lowest elevations, where habitat destruction is greatest. At higher elevations, we observed clear upward shifts in the elevational ranges of species, consistent with the influence of global warming. Taken together, these long-term data reveal the interacting negative effects of human-induced changes on both the climate and habitat available to butterfly species in California. Furthermore, the decline of ruderal, disturbance-associated species indicates that the traditional focus of conservation efforts on more specialized and less dispersive species should be broadened to include entire faunas when estimating and predicting the effects of pervasive stressors.

Florivory can have significant negative effects on plant fitness, driving selection for resistance traits in flowers. In particular, herbivory to leaves may induce resistance in flowers because herbivores on leaves often become florivores on flowers as plant ontogeny proceeds. The literature on inducible resistance in floral tissues is limited, so we used a series of experiments to determine whether prior leaf damage by Spodoptera exigua (Hubner) caterpillars affected florivore preference and performance on wild radish (Raphanus sativus L.). We found that Spodoptera exigua larvae preferred petals from control plants versus petals from plants exposed to prior leaf damage, and that larvae gained more mass on petals from control plants, although this depended on the presence of anthocyanins in the petals. Our results suggest that leaf damage can induce changes in petals that reduce Spodoptera exigua larval fitness. Keywords: anthocyanins, floral herbivory, florivory, induced resistance, Raphanus sativus. La florivorie peut avoir un effet négatif significatif sur la valeur adaptative de la plante, encourageant le développement de traits de résistance chez les fleurs. En particulier, l'herbivorie des feuilles peut induire une résistance chez les fleurs car les herbivores de feuilles deviennent souvent florivores au fur et à mesure de la progression de l'ontogénie. La littérature portant sur la résistance inductible dans les tissus floraux est limitée; les auteurs ont donc réalisé une série d'expériences afin de déterminer si un dommage antérieur causé aux feuilles par la chenille Spodoptera exigua (Hübner) affectait la préférence et la performance du florivore sur le radis sauvage (Raphanus sativus L.). Ils ont trouvé que les larves de Spodoptera exigua préféraient les pétales des plants contrôles comparativement aux pétales des plants exposés à un dommage antérieur aux feuilles, et que les larves prenaient davantage de poids avec les pétales des plants contrôles, quoi que ceci dépendait de la présence d'anthocyanines dans les pétales. Leurs résultats suggèrent que le dommage aux feuilles peut induire des changements dans les pétales qui réduisent la valeur adaptative des larves de Spodoptera exigua. [Traduit par la Rédaction] Mots-clés : anthocyanines, broutage floral, florivorie, résistance induite, Raphanus sativus., Introduction Many different types of herbivores may feed on a plant during its growth and development. Some of these herbivores specialize on particular parts of the plant, while others are [...]

Damage to flowers by herbivores, or florivory, can have direct impacts on gamete survival and can also indirectly affect fitness by reducing pollinator service. While recent studies have examined the impact of natural or artificial floral damage, very few researchers have manipulated both damage and pollen addition to see whether pollen limitation is enhanced by damage, and no workers, to my knowledge, have examined whether pollen limitation is dependent on the levels of florivory used. I used a pollen addition treatment and six levels of artificial floral damage to investigate whether damage increases pollen limitation and whether that pollen limitation becomes more severe with increasing numbers of petals damaged in Nemophila menziesii Hook. & Arn. 1 found that artificial floral damage that mimics natural florivore damage increases pollen limitation, and that this pollen limitation generally increased with increasing numbers of petals damaged. The treatment with the heaviest amount of damage did not suffer the most pollen limitation, perhaps because flowers in this treatment remained radially symmetric. These findings suggest that florivory may decrease pollen import through pollinator deterrence and could thus serve as a selective force on either floral or defense traits in outcrossing plant populations. Key words: florivory, floral herbivory, floral symmetry, pollen limitation, pollination. Les dommages aux fleurs par les herbivores ou florivorie, peuvent exercer des impacts directs sur la survie des gametes et peuvent aussi affecter indirectement l'adaptation en reduisant les services des pollinisateurs. Alors que de recentes etudes ont porte sur l'impact des dommages naturels et artificiels sur les fleurs, tres peu de chercheurs ont manipide a la fois l'addition de pollen ou leur dommage afin de verifier si ces dommages n'augmentent la limitation pollinique et aucun chercheur, a la connaissance de l'auteur, a cherche a savoir si la limitation pollinique depend des intensites de florivorie utilisees. L'auteur a effectue des additions de pollen ainsi que six degres de dommages floraux artificiels, afin de determiner si les dommages augmentent la limitation pollinique et si cette limitation devient plus severe avec une augmentation du nombre de petales endommagees, chez le Nemophila menziesii Hook. & Am, Il a constate que le dommage artificiel aux fleurs imitant le dommage naturel par florivorie augmente la limitation pollinique et que celle limitation du pollen augmente generalement avec une augmentation du nombre de petales endommagees. Le traitement imposant les plus forts dommages n'a pas conduit a la plus forte limitation pollinique. peut-etre parce que les fleurs ayant subi ce traitement sont demeurees radialement symetriques. Ces observations suggerent que la florivorie peut diminuer l'apport de pollen en eloignant les pollinisateurs, et pourrait ainsi agir comme force selective sur les caracteres floraux ainsi que de defense dans les populations vegetales a intercroisements. Mots-des: florivorie, herbivorie llorale, symetrie florale, limitation pollinique, pollinisation., Introduction Plants are subject to many different types of herbivory at different points in their growth and development. Most research on herbivory has focused on damage to leaves, although recent [...]

Studies done on adult corn-rootworm beetles, important pests of corn on sunflowers in prairie remnants in southeast Minnesota are presented. Diarbotica barberi feeding extensively on sunflower pollen and rarely on other flower parts, such as petals were observed.