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Moth Populations (moth + population)
Selected AbstractsCountryside Biogeography of Moths in a Fragmented Landscape: Biodiversity in Native and Agricultural HabitatsCONSERVATION BIOLOGY, Issue 2 2001Taylor H. Ricketts We sampled moth species richness within a 227-ha forest fragment and in four surrounding agricultural habitats (coffee, shade coffee, pasture, and mixed farms) in southern Costa Rica. We found no significant difference in moth species richness or abundance among agricultural habitats, but agricultural sites within 1 km of the forest fragment had significantly higher richness and abundance than sites farther than 3.5 km from the fragment. In addition, species composition differed significantly between distance classes ( but not among agricultural habitats), with near sites more similar to forest than far sites. These results suggest that (1) different agricultural production regimes in this region may offer similar habitat elements and thus may not differ substantially in their capacities to support native moth populations and (2) that the majority of moths may utilize both native and agricultural habitats and move frequently between them, forming "halos" of relatively high species richness and abundance around forest fragments. Correlations between species richness and the amount of nearby forest cover, measured over circles of various radii around the sites, suggest that halos extend approximately 1.0,1.4 km from the forest edge. The extent of these halos likely differs among taxa and may influence their ability to survive in fragmented landscapes. Resumen: Los estudios de paisajes fragmentados, especialmente en los trópicos, tradicionalmente se han enfocado en los fragmentos nativos per se, ignorando las distribuciones de especies en áreas agrícolas circundantes o en otras áreas dominadas por humanos. Muestreamos la riqueza de polillas dentro de un fragmento de bosque de 227 hectáreas y en cuatro hábitats agrícolas (café, café con sombra, pastizal y campos mixtos) en el Sur de Costa Rica. Encontramos que no hubo diferencias significativas en la riqueza de especies o en la abundancia de polillas entre los hábitats agrícolas, sin embargo, los sitios agrícolas cercanos (<1 km) al fragmento de bosque tuvieron una riqueza de especies y abundancia significativamente mayor que las de los sitios lejanos (>3.5 km) al fragmento. Además, la composición de especies fue significativamente diferente entre las clases de distancia ( pero no entre los hábitats agrícolas), siendo los sitios cercanos más similares al bosque que los sitios retirados. Estos resultados sugieren que (1) los diferentes regímenes de producción agrícola en esta región pueden ofrecer elementos de hábitat similares y por lo tanto pueden no diferir substancialmente en lo que se refiere a su capacidad para sostener poblaciones de polillas nativas y (2) que la mayoría de las polillas pueden utilizar tanto hábitatsnativos como agrícolas y mover frecuentemente entre ellos, formando "halos" con una riqueza de especies y una abundancia relativamente altas alrededor de los fragmentos del bosque. Las correlaciones entre la riqueza de especies y la cantidad de cobertura forestal circundante, medida en círculos de diferente radio alrededor de los sitios de estudio, sugiere que los halos se extienden aproximadamente 1.0,1.4 km del borde del bosque. La extension de estos halos posiblemente difiere entre taxones y puede influenciar sus habilidades para sobrevivir en paisajes fragmentados. [source] Is there a higher risk for herbivore outhreaks after cold mast years?ECOGRAPHY, Issue 6 2000An analysis of two plant/herbivore series from southern Norway Historical data on two plant-herbivore interactions from southern Norway were used to test the hypothesis that the degree of herbivore outbreaks in post-mast years is negatively related to summer temperatures in the mast year, because plants are more depressed after a high seed production if temperatures and thus the photosynthetic activity is low. The plant species were the sessile oak Quercus petraea and the bilberry Vaceinium myrtillus. For the former species post-mast years were identified from reports given by the local forest authorities for the period 1930,48, and from acorn export curves for the period 1949,98, For the latter species, post-mast years were identified mainly from bilberry export curves for the period 1920,31, from game reports for the period 1932,78. and from diary notes for the period 1979,87. The herbivore species used were the green oak leaf roller moth Tortrix viridana and the capercaillie Tetrao urogallus. Eight moth outbreaks on oak forests were reported by the forest authorities in the period 1930,98, and they all started in a post-mast year of the sessile oak. There were however also eleven post-mast years without moth outbreaks. According to game reports, observations and autumn counts, all increases in the autumn population size of capercaillie during 1920 88 occurred in or after a year with high bilberry production. Among i8 post-mast years, there were seven with strong increase, seven with slight or moderate increase, and four with no increase. For both herbivore species, post-mast years with marked population increases had significantly lower summer temperatures in the preceding (mast) year than had post-mast years with no or slight increases. For moth populations there also was a negative effect of high temperatures in April, possibly because moth eggs tend to hatch too early relative lo budburst if spring temperatures are high. For the capercaillie, high amount of precipitation in June , July seemed to have some negative impact on the autumn population sizes, as also found in previous studies. [source] Species-specific differences in oak foliage affect preference and performance of gypsy moth caterpillarsENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2003L. K. Foss Abstract The gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), is an introduced defoliator that preferentially feeds on oaks, Quercus spp. (Fagaceae) in the north-eastern USA. As the gypsy moth expands its geographic range, the extensive oak component in forests and urban environments of the USA assure its successful establishment. Given their economic and ecological importance, and the gypsy moth's potential to cause mortality, we evaluated caterpillar preference and performance on various oaks prevalent in the central hardwoods region. Most of the physical and chemical characteristics we measured, from budbreak phenology to foliar chemistry, varied significantly among the oak species tested. Similarly, insect preference and performance varied significantly, though not always in predictable ways. Caterpillar preference was compared for black, Q. velutina Lamarck, burr, Q. macrocarpa Michaux, cherrybark, Q. pagoda Rafinesque, northern red, Q. rubra L., pin, Q. palustris Muenchhausen, swamp white, Q. bicolor Willdenow, white, Q. alba L., and willow, Q. phellos L., oaks. Gypsy moth preference was greatest for black and burr, and least for northern red, pin, and willow oaks. We assessed foliar characteristics and caterpillar performance on foliage from burr, cherrybark, northern red, pin, and willow oaks. Caterpillar preference did not always correlate with performance. Gypsy moth consumption and growth were highest, and development most rapid, on pin oak, which had high nitrogen and tannin levels, and was among the least preferred. Northern red and willow oaks were also among the least preferred and were the least suitable tested, producing caterpillars with moderate to low consumption and growth rates, as well as the longest development. Northern red oak contained the lowest foliar tannins; willow oak foliage was lowest in carbohydrates and nitrogen. Our results suggest that a combination of foliar characteristics may be responsible for gypsy moth preference and performance, and that an optimal combination of foliar components serves to maximize host suitability. These data will provide information useful for planning and managing urban forests in the presence of expanding gypsy moth populations. [source] Effect of weather factors on populations of Helicoverpa armigera moths at cotton-based agro-ecological sitesENTOMOLOGICAL RESEARCH, Issue 1 2009Ghulam Mustafa AHEER Abstract Pheromone trapping was used to monitor populations of the moth Helicoverpa armigera at five cotton-based agro-ecological sites , river, vegetable, orchard, forest and clean cultivation (areas under only cotton cultivation) , in the Bahawalpur district, Pakistan. Three locations at each site were chosen and three pheromone traps at each location were installed in cotton fields. Moth catches were recorded at 15,20 day intervals from 24 October 2004 to 19 December 2006. In 2004, the river sites showed the maximum trapped population of H. armigera (0.22/trap) followed by 0.165 per trap at the vegetable sites. Orchard, clean cultivation and forest sites had zero moth catches. In 2005, the river sites again showed the highest trapped population (0.57/trap), followed by clean cultivation (0.45/trap), vegetable (0.44/trap), orchard (0.40/trap) and forest (0.29/trap). The moths appeared during July to December and March to May. In 2006, sites showed non-significant difference, with a population range of 0.47 to 0.97 moths per trap. On average, river sites peaked at 0.49 per trap, followed by vegetable (0.38), clean cultivation (0.47), orchard (0.35) and forest (0.25) sites. The peak was observed on 3 April 2006, and moths appeared during February to July and October to December. The minimum temperature in river, forest and clean cultivation sites; the maximum temperature in orchard sites; and the average temperature in river, orchard, forest and clean cultivation sites showed significant positive correlations with trapped moth populations. Relative humidity showed significant negative correlation with population at the orchard sites in 2005. All weather factors during 2004 and 2006 showed non-significant correlations with the moth populations. No model was found to be best fit by multiple linear regression analysis; however, relative humidity, minimum temperature, maximum temperature, minimum temperature and maximum temperature contributed 8.40, 10.23, 2.43, 4.53 and 2.53% to the population fluctuation of the moth at river, vegetable, orchard, forest and clean cultivation sites, respectively. [source] Identification and analysis of Lydia, a LTR retrotransposon from Lymantria disparINSECT MOLECULAR BIOLOGY, Issue 4 2000T. A. Pfeifer Abstract Degenerative PCR primers to conserved amino acid motifs were used to identify an LTR retrotransposon from Lymantria dispar. The isolated retrotransposon, Lydia, is 6655 base pairs (bp) in length and contains perfect 300 bp terminal repeats. The identified gag and pol related ORFs have a high degree of similarity to the corresponding regions of the retrotransposon Ted from Trichoplusia ni, although several reading frameshifts and missense mutations are evident. The high degree of similarity between Lydia and Ted LTRs lends support for a family of lepidopteran retrotransposons. Southern blot analysis of individuals from two geographically distinct gypsy moth populations demonstrates that Lydia is found in both populations and the position of this element within the genome of these isolated populations is variable. [source] Host behaviour and exposure risk in an insect,pathogen interactionJOURNAL OF ANIMAL ECOLOGY, Issue 4 2010Benjamin J. Parker Summary 1.,Studies of variability in host resistance to disease generally emphasize variability in susceptibility given exposure, neglecting the possibility that hosts may vary in behaviours that affect the risk of exposure. 2.,In many insects, horizontal transmission of baculoviruses occurs when larvae consume foliage contaminated by the cadavers of virus-infected conspecific larvae; so, host behaviour may have a strong effect on the risk of infection. 3.,We studied variability in the behaviour of gypsy moth (Lymantria dispar) larvae, which are able to detect and avoid virus-contaminated foliage. 4.,Our results show that detection ability can be affected by the family line that larvae originate from, even at some distance from a virus-infected cadaver, and suggest that cadaver-detection ability may be heritable. 5.,There is thus the potential for natural selection to act on cadaver-detection ability, and thereby to affect the dynamics of pathogen-driven cycles in gypsy moth populations. 6. We argue that host behaviour is a neglected component in studies of variability in disease resistance. [source] Spatial population structure of a specialist leaf-mining mothJOURNAL OF ANIMAL ECOLOGY, Issue 4 2008Sofia Gripenberg Summary 1The spatial structure of natural populations may profoundly influence their dynamics. Depending on the frequency of movements among local populations and the consequent balance between local and regional population processes, earlier work has attempted to classify metapopulations into clear-cut categories, ranging from patchy populations to sets of remnant populations. In an alternative, dichotomous scheme, local populations have been classified as self-sustaining populations generating a surplus of individuals (sources) and those depending on immigration for persistence (sinks). 2In this paper, we describe the spatial population structure of the leaf-mining moth Tischeria ekebladella, a specialist herbivore of the pedunculate oak Quercus robur. We relate moth dispersal to the distribution of oaks on Wattkast, a small island (5 km2) off the south-western coast of Finland. 3We build a spatially realistic metapopulation model derived from assumptions concerning the behaviour of individual moths, and show that the model is able to explain part of the variation in observed patterns of occurrence and colonization. 4While the species was always present on large trees, a considerable proportion of the local populations associated with small oaks showed extinction,recolonization dynamics. The vast majority of moth individuals occur on large trees. 5According to model predictions, the dominance of local vs. regional processes in tree-specific moth dynamics varies drastically across the landscape. Most local populations may be defined broadly as ,sinks', as model simulations suggest that in the absence of immigration, only the largest oaks will sustain viable moth populations. Large trees in areas of high oak density will contribute most to the overall persistence of the metapopulation by acting as sources of moths colonizing other trees. 6No single ,metapopulation type' will suffice to describe the oak,moth system. Instead, our study supports the notion that real populations are often a mix of earlier identified categories. The level to which local populations may persist after landscape modification will vary across the landscape, and sweeping classifications of metapopulations into single categories will contribute little to understanding how individual local populations contribute to the overall persistence of the system. [source] Comparative effects of deltamethrin and Neem kernel solution treatments on Diamondback moth and Cotesia plutellae (Hym., Braconidae) parasitoid populations in the Cotonou peri-urban area in BeninJOURNAL OF APPLIED ENTOMOLOGY, Issue 3-4 2000A. E. Goudegnon A comparison between deltamethrin and Neem kernel solution treatments on Plutella xylostella (L.) populations was made in the Cotonou peri-urban area. Diamondback moth populations were 10 times larger in deltamethrin plots, than in Neem plots after treatment. The number of marketable cabbages from Neem-treated plots was 1.5 times greater than the number from deltamethrin-treated plots. There was no apparent effect of either treatments on Cotesia plutellae (Kurdjumov) populations, the only parasitoid of the pest that was present in the area. [source] Local outbreaks of Operophtera brumata and Operophtera fagata cannot be explained by low vulnerability to pupal predationAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 1 2010Annette Heisswolf 1One of the unresolved questions in studies on population dynamics of forest Lepidoptera is why some populations at times reach outbreak densities, whereas others never do. Resolving this question is especially challenging if populations of the same species in different areas or of closely-related species in the same area are considered. 2The present study focused on three closely-related geometrid moth species, autumnal Epirrita autumnata, winter Operophtera brumata and northern winter moths Operophtera fagata, in southern Finland. There, winter and northern winter moth populations can reach outbreak densities, whereas autumnal moth densities stay relatively low. 3We tested the hypothesis that a lower vulnerability to pupal predation may explain the observed differences in population dynamics. The results obtained do not support this hypothesis because pupal predation probabilities were not significantly different between the two genera within or without the Operophtera outbreak area or in years with or without a current Operophtera outbreak. 4Overall, pupal predation was even higher in winter and northern winter moths than in autumnal moths. Differences in larval predation and parasitism, as well as in the reproductive capacities of the species, might be other candidates. [source] Local adaptation in a plant herbivore interaction depends on the spatial scaleBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2009RODRIGO COGNI Local adaptation has central importance in the understanding of co-evolution, maintenance of sexual reproduction, and speciation. We investigated local adaptation in the alkaloid-bearing legume Crotalaria pallida and its seed predator, the arctiid moth Utetheisa ornatrix, at different spatial scales. When we studied three populations from south-east Brazil (150 km apart), we did not find evidence of local adaptation, although we did find interpopulational differences in herbivore performance, and a significant interaction between herbivore sex and plant population. These results indicate that both moth and plant populations are differentiated at the regional scale. In a comparison of populations from Brazil and Florida, the herbivore showed local adaptation to its host plant; for both moth populations, the pupae were heavier when the larvae ate the sympatric than the allopatric host population. We discuss the scale dependence of our results and the possible causes for the lack of local adaptation at the regional scale, even in the presence of plant and moth differentiation. The results obtained demonstrate the importance of studying co-evolution and local adaptation at different geographical scales. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 494,502. [source] | ||||||||||