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Flight Season (flight + season)
Selected AbstractsParasitism by the mite Trombidium breei on four U.K. butterfly speciesECOLOGICAL ENTOMOLOGY, Issue 6 2002L. Conradt Abstract 1. The incidence of parasitism by larvae of the mite species Trombidium breei was reported in one population of the lycaenid butterfly Polyommatus icarus, four populations of the satyrine butterfly Maniola jurtina, one population of the satyrine butterfly Aphantopus hyperanthus, and two populations of the satyrine butterfly Pyronia tithonus, as well as on one specimen of the dipteran Alophorus hemiptera. A considerable proportion of butterflies (11-50%) was infested in all study populations. 2. The pattern of infestation was examined in detail in M. jurtina. Males had a significantly higher incidence of infestation than females, and middle-aged butterflies had a higher incidence of infestation than old or young butterflies. The incidence of infestation peaked in the middle of the flight season, and this seasonal effect was independent of the effect of butterfly age. 3. Using a model based on capture-recapture data, it was estimated that a hypothetical ideal male M. jurtina that lives exactly the mean expected lifespan of 9-10 days has an approximately 75% chance of becoming infested with mites at least once during its lifetime, a mean time to first infestation of 3-4 days, and an average infestation persistence time of 2-3 days. 4. Capture-recapture data failed to show any effect of mite infestation on the lifespan or within-habitat movement rate of M. jurtina. 5. In experiments in which individual butterflies were taken out of their normal habitat and released, M. jurtina and P. tithonus that were infested with mite larvae did not differ from uninfested individuals in the efficiency with which they returned to suitable habitat. Thus, parasitism by T. breei larvae had no detectable effects on flight performance or orientation ability. 6. The results suggest that trombidiid mite larvae have limited potential in the biological control of insect pests. [source] Difference in the time of mating activity between host-associated populations of the rice stem borer, Chilo suppressalis (Walker)ENTOMOLOGICAL SCIENCE, Issue 3 2006Hideki UENO Abstract Mating activities of the rice stem borer, Chilo suppressalis, were compared between rice- and wateroat-feeding populations, and two potential temporal factors that may act as reproductive barriers were examined. Seasonal data of the number of moths attracted to pheromone traps showed that the peak of emergence at the rice field was approximately 10 days earlier than that at the wateroat vegetation in the first flight season, although there was a broad overlap of emergence at the two locations. Both field observations and a laboratory experiment showed that moths from the rice field started mating earlier than those from the wateroat vegetation. However, whereas the difference was distinctive in the laboratory experiment, mating activity at the wateroat vegetation shifted significantly to an earlier time phase than that observed in the laboratory. Body size data showed that the male moths attracted to the pheromone traps at the wateroat vegetation were significantly larger than those at the rice field, suggesting that the traps at the two locations mainly attracted moths originating from different host plants. However, pheromone-trapped males at the rice field were significantly larger than those reared from overwintering samples. These results support the idea that males from the wateroat vegetation migrate to the rice field. The differences in seasonal and temporal mating activity and their effects on development of reproductive isolation between host-associated populations are discussed. [source] Voltinism flexibility of a riverine dragonfly along thermal gradientsGLOBAL CHANGE BIOLOGY, Issue 3 2008ERIK BRAUNE Abstract Potential effects of future warming should be reflected in life history patterns of aquatic organisms observed in warmer climates or in habitats that are different in ambient temperature. In the special case of the dragonfly Gomphus vulgatissimus (L.) (Odonata: Gomphidae) previous research suggests that voltinism decreases from south to north. We analysed data on voltinism from 11 sample sites along a latitudinal gradient from about 44°N to 53°N, comprising small streams to medium-sized rivers. Furthermore, to simulate different conditions and to allow projections for future climate change scenarios, we developed a population dynamic model based on a projection matrix approach. The parameters of the model are dependent on temperature and day length. Our field results indicate a decrease in voltinism along the latitudinal gradient from southern to northern Europe and a corresponding increase of voltinism with higher temperatures. An increase in voltinism with width of the running water implies an effect of varying habitat temperature. Under the impact of global warming, our model predicts an increased development speed, particularly in the northern part of the latitudinal gradient, an extension of the northern range limit and changes in phenology of G. vulgatissimus, leading to an extension of the flight season in certain regions along the gradient. [source] Sirex noctilio in North America: the effect of stem-injection timing on the attractiveness and suitability of trap treesAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010Kelley E. Zylstra 1Sirex noctilio Fabricius, an invasive woodwasp responsible for severe economic damage to pine industries in the southern hemisphere, is now established in the northeastern U.S.A. and portions of eastern Canada. 2Parts of North America are considered to be high risk for S. noctilio invasion. Effective detection tools, including trap trees, are needed to monitor and survey S. noctilio populations. 3The present study was conducted to determine the optimal time to chemically stress a tree when aiming to attract the most S. noctilio to the host substrate, as well as to determine which timing produced the most adult progeny. Both of these measures (host attraction and host suitability for development) support the main objectives of the study by offering improved methods for monitoring and management of S. noctilio. 4Red pine (Pinus resinosa) and Scots pine (Pinus sylvestris) were treated with Dicamba at three time intervals. Multiple funnel lindgren traps were placed on these trees and, at the end of the flight season, the treatment trees were felled and brought into the laboratory. The number of S. noctilio caught in the traps (host attraction) and the number of S. noctilio emerged from the treated trees (host suitability) were determined. 5Optimal timing of the chemical girdle was dependent on host species. Significantly more female S. noctilio were captured on trap trees prepared 1 month before flight (red pine and Scots pine) or prepared at flight (Scots pine) compared with other treatments. There were also significantly more females reared from Scots pine trap trees prepared at flight and red pine trap trees prepared 1 month before and/or at flight. 6By the beginning of August, most (79%) of the S. noctilio for the flight season were caught in the traps at the trap trees. The sex ratio (males : females) was closer to 1 : 1 than previously reported in studies from other countries. 7The results obtained in the present study demonstrate that timing is important when creating a trap tree with herbicide in North America, whether for the purpose of detection or as part of a biological control effort. [source] Using age grading by wing injuries to estimate size-dependent adult survivorship in the field: a case study of the yellow dung fly Scathophaga stercorariaECOLOGICAL ENTOMOLOGY, Issue 5 2002Dieter U. Burkhard Abstract 1. Studies of natural selection depend on estimates of longevity and mortality in the wild. In small and mobile species such as insects, direct, mark,recapture (resight), studies are difficult to perform because individuals cannot be tracked easily. 2. It was investigated whether age grading based on wing injuries alone can be used to estimate size-specific survivorship in the field in the yellow dung fly Scathophaga stercoraria (L.) (Diptera: Scathophagidae). 3. The accumulation of different types of wing injury throughout the spring and autumn flight seasons for both sexes was recorded: tears, notches (both reflecting regular wear), and large missing areas (probably due to intra- and inter-specific interactions). 4. Female longevity increased with body size in both spring and autumn, whereas male longevity increased slightly with size in spring but decreased in autumn. 5. The two sexes and males of different size classes accumulated the various types of wing injury differentially, presumably due to differential patterns of intraspecific interactions. Additionally, body size exhibited a seasonal pattern, complicating interpretation of the relationship between body size and wing injuries. 6. It is therefore concluded that estimating adult viability selection on body size using wing injuries is problematic in dung flies, and potentially also in other species. It is suggested that before this method is applied in any particular species, pilot studies should be conducted to verify whether wing injuries accumulate equally in all classes of individuals of interest. In addition, it is necessary to investigate the causes of different types of wing injury. [source] | ||||||||||