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David R. Mercer - One of the best experts on this subject based on the ideXlab platform.
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Vertical Oviposition and Lambornella clarki (Ciliophora: Tetrahymenidae) Dispersal by Aedes sierrensis (Diptera: Culicidae) in California
Journal of vector ecology : journal of the Society for Vector Ecology, 2010Co-Authors: David R. Mercer, Jan O. Washburn, John R. AndersonAbstract:Vertical stratification of Treeholes used by mosquitoes may reflect resource quality or result from interspecific competition. Mosquitoes able to monopolize Treeholes with optimal resources may be over-represented in the community. Aedes sierrensis, which is well adapted for the Mediterranean climate of California, has evolved in the absence of interspecific competition, so oviposition should reflect resource quality to a large extent. Artificial oviposition traps mounted at four canopy heights facing north or south on trees in a mixed-oak forest at four elevations of the Pacific Coastal Range were used to assess vertical ovipositional preferences by the western Treehole mosquito. Natural dispersal of the ciliated protozoan parasite Lambornella clarki was similarly monitored. Gravid Ae. sierrensis showed no vertical stratification during egg laying in traps. Lambornella clarki were naturally dispersed at relatively low frequency into traps and persisted unless eliminated by larval predation. Aedes sierrensis is not currently constrained into occupying a subset of Treeholes. However, invasion of its native range by competitive species may alter oviposition patterns.
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Sexual differences in larval molting rates in a protandrous mosquito (Diptera: Culicidae) species, Aedes sierrensis.
Journal of medical entomology, 2008Co-Authors: David R. Mercer, Angela Schoergendorfer, Rhonda VandykeAbstract:Day-old larval Aedes sierrensis collected from six newly flooded Treeholes in northern California were reared individually in the laboratory under simulated field conditions to compare larval developmental rates of males and females. Time to adult eclosion ranged from 133 to 219 d for this generally univoltine, winter-developing species. Males experienced significantly shorter first, second, and third larval instars than females. Females spent significantly less time as fourth instars (whose endpoint is determined by photoperiod). Length of pupal stage was equal for males and females. Time to mean adult eclosion differed among Treeholes but was not determined by latitudinal position of Treehole. Wing lengths were shorter for males than females in this sexually dimorphic species and also differed significantly among Treeholes. Wing lengths were significantly correlated with total developmental time, but females spending more time in the fourth instar did not emerge as larger adults. In natural Treeholes, resource utilization during rapid development by Ae. sierrensis males may limit the size and number of females produced from the same cohort if resources are limiting.
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Correlation between colorimetric and protein-precipitation assays of tannins dissolved in Treehole water.
Journal of medical entomology, 1996Co-Authors: David R. MercerAbstract:There was a significant correlation between colorimetric and protein-precipitation assays of tannins dissolved in Treehole water. The protein-precipitation potential of early-season Treehole water was extremely low relative to total phenolics measured by colorimetry. The protein-precipitation method is recommended because it directly measures protein binding, the property of dissolved tannins relevant to mosquito development. Furthermore, the procedure is not affected by Treehole water color and does not produce dangerous wastes.
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Tannins in Treehole habitats and their effects on Aedes sierrensis (Diptera: Culicidae) production and parasitism by Lambornella clarki (Ciliophora: Tetrahymenidae).
Journal of medical entomology, 1994Co-Authors: David R. Mercer, John R. AndersonAbstract:Tannin concentration, measured as total phenolics, varied widely in natural Treehole water throughout the period of development for Aedes sierrensis (Ludlow), the western Treehole mosquito. Tannic acid induced a parasitic response in free-living populations of the protozoan Lambornella clarki Corliss & Coats, an effect not entirely explained by acidity. Tannic acid concentration influenced mosquito developmental rates, survival, size, and proportion females more than food level, L. clarki parasite exposure, or any interaction of treatments for Ae. sierrensis populations reared in artificial microcosms exposed to natural conditions.
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Effect of tannic acid concentration on development of the western Treehole mosquito,Aedes sierrensis (Diptera: Culicidae)
Journal of Chemical Ecology, 1993Co-Authors: David R. MercerAbstract:Populations of Aedes sierrensis (Ludlow) completed development in tannic acid solutions over a wide concentration range (i.e., 0–1.0 g/liter) in artificial microcosms exposed to field conditions. The most notable effects of high tannic acid concentration were to slow larval developmental rates and to reduce numbers of adults produced; adult size and sex ratio were minimally affected. Vector potential of the western Treehole mosquito is discussed in terms of tannin concentration.
Christopher J. Paradise - One of the best experts on this subject based on the ideXlab platform.
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Open Access Density-Dependent Predation of a Dominant Species does not Facilitate Increased Diversity in Treeholes
2016Co-Authors: Leslie M. Smith, Jarrod Blue, Jessica Carlson, Grace Metz, Joshua Haywood, Daniel Bush, Christopher J. ParadiseAbstract:Abstract: The effects of predation on water-filled Treehole communities in North Carolina were examined using mesocosm experiments and observations in natural Treeholes. The presence of the predator Toxorhynchites rutilus and leaf litter abundance were manipulated in mesocosms to examine interactions between resources and predation. Long-term examination of interactions in unmanipulated Treeholes provided data on natural variation in water volume and predator density. Toxorhynchites rutilus preys upon two common Treehole insects, Aedes triseriatus and Culicoides guttipennis. We predicted that T. rutilus would act as a keystone predator and reduce the density of these dominant species. This would allow other species to coexist and lead to an increase in diversity. We also predicted that effects of predation would be reduced in habitats with high levels of resources, due to either increased refugia or decreased competition. The results did not entirely support the predictions. In both mesocosms and Treeholes T. rutilus depressed densities of the most abundant prey type, A. triseriatus. In Treeholes, the presence of T. rutilus depressed densities of the midge C. guttipennis, and predator densities were positively associated with insect diversity in Treeholes. Strikingly, higher diversity was also associated with high densities of the dominant prey in Treeholes. In addition, mesocosms showed no relationship between T. rutilus presence and species diversity. The relationship between the predator and diversity in Treeholes appears to be unrelated to predation on the dominant competitors and is instead caused by some other habitat characteristic. While there were effects of resources on densities and diversity in both mesocosms and Treeholes, neither of the resources analyzed
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Density-Dependent Predation of a Dominant Species does not Facilitate Increased Diversity in Treeholes
The Open Ecology Journal, 2009Co-Authors: Leslie Smith, Jessica Carlson, Grace Metz, Joshua Haywood, Daniel Bush, Jarrod D Blue, Christopher J. ParadiseAbstract:The effects of predation on water-filled Treehole communities in North Carolina were examined using mesocosm experiments and observations in natural Treeholes. The presence of the predator Toxorhynchites rutilus and leaf litter abundance were manipulated in mesocosms to examine interactions between resources and predation. Long-term examination of interactions in unmanipulated Treeholes provided data on natural variation in water volume and predator density. Toxorhynchites rutilus preys upon two common Treehole insects, Aedes triseriatus and Culicoides guttipennis. We predicted that T. rutilus would act as a keystone predator and reduce the density of these dominant species. This would allow other species to coexist and lead to an increase in diversity. We also predicted that effects of predation would be reduced in habitats with high levels of resources, due to either increased refugia or decreased competition. The results did not entirely support the predictions. In both mesocosms and Treeholes T. rutilus depressed densities of the most abundant prey type, A. triseriatus. In Treeholes, the presence of T. rutilus depressed densities of the midge C. guttipennis, and predator densities were positively associated with insect diversity in Treeholes. Strikingly, higher diversity was also associated with high densities of the dominant prey in Treeholes. In addition, mesocosms showed no relationship between T. rutilus presence and species diversity. The relationship between the predator and diversity in Treeholes appears to be unrelated to predation on the dominant competitors and is instead caused by some other habitat characteristic. While there were effects of resources on densities and diversity in both mesocosms and Treeholes, neither of the resources analyzed, leaf litter or water, appear to be the sole characteristic that mutually allows for large populations of T. rutilus and high species diversity. We conclude that though T. rutilus is an aggressive predator, it does not cause an increase in prey species diversity as a keystone predator would. Further research is needed to determine the conditions that favor the presence of predator and high prey diversity.
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Local and regional factors influence the structure of Treehole metacommunities
BMC ecology, 2008Co-Authors: Christopher J. Paradise, Leslie Smith, Jarrod D Blue, John Q Burkhart, Justin Goldberg, Lauren Harshaw, Katherine D Hawkins, Benjamin Kegan, Tyler Krentz, Shawn VillalpandoAbstract:Abiotic and biotic factors in a local habitat may strongly impact the community residing within, but spatially structured metacommunities are also influenced by regional factors such as immigration and colonization. We used three years of monthly Treehole census data to evaluate the relative influence of local and regional factors on our study system. Every species responded to at least one of three local environmental factors measured: water volume, leaf litter mass, and presence of a top predator. Several species were affected by water volume, and a non-exclusive group of species were influenced by leaf litter mass. Relative abundance of Aedes triseriatus was higher in Treeholes with higher volumes of water, and relative abundances of three out of six other species were lower in Treeholes with higher volumes of water. Leaf litter mass positively affected densities of Aedes triseriatus and relative abundance of several dipteran species. The density of the top predator, Toxorhynchites rutilus, affected the relative abundance of the two most common species, A. triseriatus and Culicoides guttipennis. Treeholes with T. rutilus had an average of two more species than Treeholes without T. rutilus. We found little evidence of synchrony between pairs of Treeholes, either spatially or temporally. There were high levels of spatial and temporal turnover, and spatial turnover increased with distance between patches. The strong effects of water volume, leaf litter mass, and presence of a top predator, along with the high temporal turnover strongly suggest that species presence and density are determined by local factors and changes in those factors over time. Both low water volume and high predator densities can eliminate populations in local patches, and those populations can recolonize patches when rain refills or predators exit Treeholes. Population densities of the same species were not matched between pairs of Treeholes, suggesting variation in local factors and limited dispersal. Distance effects on spatial turnover also support limitations to dispersal in the metacommunity, and we conclude that the weight of evidence favors a strong influence of local factors relative to regional factors.
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BMC Ecology BioMed Central
2008Co-Authors: Christopher J. Paradise, Leslie Smith, Jarrod D Blue, John Q Burkhart, Justin Goldberg, Lauren Harshaw, Katherine D Hawkins, Benjamin Kegan, Tyler Krentz, Shawn VillalpAbstract:Research article Local and regional factors influence the structure of Treehole metacommunitie
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Prior occupation by scirtid beetles does not affect mosquito and midge populations in Treeholes
2007Co-Authors: Christopher J. Paradise, John Q Burkhart, Lauren Harshaw, Charlie Chrisawn, Benjamin Kittinger, Leslie SmithAbstract:The primary resource of temperate forest Treeholes is leaf litter, which exists along a continuum of decay states, with different insects specializing on particular states. Scirtid beetles ( Helodes pulchella ) take part in a processing chain interaction by shredding and processing leaf litter, thereby creating material for consumption by other detritivores. Variation in scirtid density and resource availability could thereby influence the distribution of resources and thus the abundance of the dominant eastern Treehole mosquito Aedes triseriatus . In addition, pupated or dead scirtid beetles typically leave behind processed or semi-processed leaf litter, particularly if the numbers of beetles is large, which potentially impacts insect communities after the beetles are gone. We tested the hypothesis that prior presence of scirtids has observable effects on the abundance of Treehole mosquito populations. We used a two-factor fully crossed design (3 leaf litter levels x 3 scirtid densities) with 4 replicate mesocosms per treatment to monitor larval insect abundance from April 2004 to June 2005. Scirtids did not persist in mesocosms to the first census of 2005. Abundance of A. triseriatus was unaffected in 2005 by either initial scirtid density or leaf litter availability. In addition, we detected no statistically significant effects of scirtids on the rate of leaf litter decay.
R. L. Escher - One of the best experts on this subject based on the ideXlab platform.
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Testing Predictions of Displacement of Native Aedes by the Invasive Asian Tiger Mosquito Aedes Albopictus in Florida, USA
Biological Invasions, 2001Co-Authors: L. P. Lounibos, R. L. Escher, G.f. O'meara, N. Nishimura, M. Cutwa, T. Nelson, R.e. Campos, S.a. JulianoAbstract:The Asian Tiger Mosquito Aedes albopictus arrived in the USA in 1985 in used automobile tires from Japan and became established in Texas. This species has since spread to become the most abundant container-inhabiting mosquito in the southeastern USA, including Florida, where it has reduced the range of another non-indigenous mosquito, Aedes aegypti . To assess the accuracy of predictions that A. albopictus would competitively exclude the native Eastern Treehole Mosquito Aedes triseriatus from tires but not from Treeholes (Livdahl and Willey (1991) Science 253: 189–191), we extensively monitored the abundances of mosquito immatures before and after the Asian Tiger invaded these habitats in south Florida. These field data failed to demonstrate exclusion of A. triseriatus from Treeholes following the establishment of A. albopictus in this microhabitat in 1991. However, A. albopictus had significantly higher metamorphic success and showed a significant increase in mean crowding on A. triseriatus in Treeholes monitored from 1991 to 1999. In urban and suburban sites, A. triseriatus was uncommon in abandoned tires even before the arrival of A. albopictus . In some wooded sites, there is evidence for a decline in numbers of A. triseriatus in used tires and cemetery vases, but the native species has not been excluded from these habitats. Overall, the negative effect of A. albopictus on A. triseriatus has been less severe than that on A. aegypti . Experiments outdoors in surrogate Treeholes showed that A. albopictus was more successful than A. triseriatus in survival to emergence in the presence of predatory larvae of the native mosquito Toxorhynchites rutilus when first instar predators encountered both prey species shortly after their hatch. Eggs of A. albopictus also hatched more rapidly than those of A. triseriatus , giving larvae of the invasive species an initial developmental advantage to escape predation. Biological traits that may favor A. albopictus are offset partly by greater Treehole occupancy by A. triseriatus and the infrequency of the invasive mosquito species in undisturbed woodlands, which mitigates against displacement of the native mosquito in these habitats.
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Daylength and Temperature Control of Predation, Body Size, and Rate of Increase in Toxorhynchites rutilus (Diptera: Culicidae)
Annals of the Entomological Society of America, 1998Co-Authors: L. P. Lounibos, D Duzak, E A Martin, R. L. EscherAbstract:Subtropical Toxorhynchites rutilus (Coquillett) frequently overwinter as 4th instars in Treeholes of peninsular Florida. Exposure from hatch to short daylengths induced 4th instar diapause in over 50% of wild T. rutilus from southern Florida. Short daylengths and lower temperatures significantly reduced prey consumption rates. At a low frequency, diapausing larvae killed prey without consuming, which behavior increased with time in the 4th instar and was distinct from killing by prepupae. Termination of diapause by transfer of 4th instars to long daylengths was accompanied by an increase in prey consumption rate prior to pupation. Mean pupal masses were significantly affected by photoperiod and temperature treatments, confirming a correlation between heavier pupae and colder temperatures in the field. At 25°C and 21°C, female pupae were significantly larger than males, in contrast to no sexual size difference observed for continuous development at 27°C. The composite index of performance (r’), an analog of the per capita rate of increase, for diapausing cohorts was one-half to two-thirds of that estimated for non-diapausing cohorts, but temperature alone did not affect r’ between 25 and 21°C. Low rates of prey consumption during winter diapause may contribute to the relatively modest, albeit significant, effect of T. rutilus predation on mosquito abundance as estimated from long-term censuses of Treeholes.
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body size sexual receptivity and larval cannibalism in relation to protandry among toxorhynchites mosquitoes
Oikos, 1996Co-Authors: L. P. Lounibos, D Duzak, R. L. Escher, E A MartinAbstract:Males of Toxorhynchites rutilis and T. amboinensis emerge as adults significantly sooner than females, the difference between sexes more pronounced in the latter species. In contrast to other protandrous mosquitoes, male and female T. rutilus do not differ in mean body mass and T. amboinensis females are only slightly larger than males. Protandry in the context of size similarity of the sexes is maintained by significantly faster growth of males. Sexual maturity is attained in both sexes approximately one day after adult eclosion. which occurs primarily in the late afternoon. Predatory fourth instar T. rutilus that co-occurred in Treeholes were far more similar in body mass than individuals of that same stage that occupied different Treeholes. In surrogate Treeholes set experimentally in nature, the rate of cannibalism was significantly higher among T. rutilus fourth instars that differed in body mass. We propose that the size similarity which minimizes larval cannibalism selects against sexual size dimorphism in adults of these species.
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Fitness of a Treehole mosquito : influences of food type and predation
Oikos, 1993Co-Authors: L. P. Lounibos, N. Nishimura, R. L. EscherAbstract:Leaves and flowers, the two main components of oak litter, were compared in the laboratory as growth substrates for larval Aedes triseriatus. Time to pupation was significantly faster and adult size significantly greater when flowers were the resource. Fitness, as measured by a composite index of performance (r'), was significantly higher among cohorts reared on flowers. A subsequent field experiment compared r' of cohorts developing in water-holding automobile tires, a common alternative habitat for Treehole mosquitoes
L. P. Lounibos - One of the best experts on this subject based on the ideXlab platform.
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Surplus Killing by Predatory Larvae of Corethrella appendiculata: Prepupal Timing and Site-Specific Attack on Mosquito Prey
Journal of Insect Behavior, 2008Co-Authors: L. P. Lounibos, S. Makhni, Barry W. Alto, B. KesavarajuAbstract:Surplus or ‘wasteful’ killing of uneaten prey has been documented in the fourth larval instar of various species of the mosquito genus Toxorhynchites that occur in Treeholes and other phytotelmata. Here we document surplus killing by the predatory midge Corethrella appendiculata , which in Florida cohabits Treeholes and artificial containers with larvae of Toxorhynchites rutilus . Provided with a surfeit of larval mosquito prey, surplus killing was observed only in the fourth instar of C. appendiculata , peaking in intensity in the final 24 h prior to pupation, as observed for Toxorhynchites spp. Attack sites identified from videotaped encounters with mosquito prey were divided among head, thorax, abdomen, and siphon. Consumed mosquito larvae ( n = 70) were attacked primarily on the head (46%) or siphon (34%), but surplus-killed prey ( n = 30) were attacked predominantly on the thorax (83%). Despite its independent evolution among different insect species in aquatic container habitats, the functional significance of prepupal surplus killing remains unclear.
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PREDATOR IDENTITY AND ADDITIVE EFFECTS IN A Treehole COMMUNITY
Ecology, 2006Co-Authors: Marcus W. Griswold, L. P. LounibosAbstract:Multiple predator species can interact as well as strongly affect lower trophic levels, resulting in complex, nonadditive effects on prey populations and community structure. Studies of aquatic systems have shown that interactive effects of predators on prey are not necessarily predictable from the direct effects of each species alone. To test for complex interactions, the individual and combined effects of a top and intermediate predator on larvae of native and invasive mosquito prey were examined in artificial analogues of water-filled Treeholes. The combined effects of the two predators were accurately predicted from single predator treatments by a multiplicative risk model, indicating additivity. Overall survivorship of both prey species decreased greatly in the presence of the top predator Toxorhynchites rutilus. By itself, the intermediate predator Corethrella appendiculata increased survivorship of the native prey species Ochlerotatus triseriatus and decreased survivorship of the invasive prey species Aedes albopictus relative to treatments without predators. Intraguild predation did not occur until alternative prey numbers had been reduced by approximately one-half. Owing to changes in size structure accompanying its growth, T. rutilus consumed more prey as time progressed, whereas C. appendiculata consumed less. The intermediate predator, C. appendiculata, changed species composition by preferentially consuming A. albopictus, while the top predator, T. rutilus, reduced prey density, regardless of species. Although species interactions were in most cases predicted from pairwise interactions, risk reduction from predator interference occurred when C. appendiculata densities were increased and when the predators were similarly sized.
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Habitat complexity and sex-dependent predation of mosquito larvae in containers
Oecologia, 2005Co-Authors: Barry W. Alto, Marcus W. Griswold, L. P. LounibosAbstract:Studies in aquatic systems have shown that habitat complexity may provide refuge or reduce the number of encounters prey have with actively searching predators. For ambush predators, habitat complexity may enhance or have no effect on predation rates because it conceals predators, reduces prey detection by predators, or visually impairs both predators and prey. We investigated the effects of habitat complexity and predation by the ambush predators Toxorhynchites rutilus and Corethrella appendiculata on their mosquito prey Aedes albopictus and Ochlerotatus triseriatus in container analogs of Treeholes. As in other ambush predator-prey systems, habitat complexity did not alter the effects of T. rutilus or C. appendiculata whose presence decreased prey survivorship, shortened development time, and increased adult size compared to treatments where predators were absent. Faster growth and larger size were due to predator-mediated release from competition among surviving prey. Male and female prey survivorship were similar in the absence of predators, however when predators were present, survivorship of both prey species was skewed in favor of males. We conclude that habitat complexity is relatively unimportant in shaping predator-prey interactions in this Treehole community, where predation risk differs between prey sexes.
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Testing Predictions of Displacement of Native Aedes by the Invasive Asian Tiger Mosquito Aedes Albopictus in Florida, USA
Biological Invasions, 2001Co-Authors: L. P. Lounibos, R. L. Escher, G.f. O'meara, N. Nishimura, M. Cutwa, T. Nelson, R.e. Campos, S.a. JulianoAbstract:The Asian Tiger Mosquito Aedes albopictus arrived in the USA in 1985 in used automobile tires from Japan and became established in Texas. This species has since spread to become the most abundant container-inhabiting mosquito in the southeastern USA, including Florida, where it has reduced the range of another non-indigenous mosquito, Aedes aegypti . To assess the accuracy of predictions that A. albopictus would competitively exclude the native Eastern Treehole Mosquito Aedes triseriatus from tires but not from Treeholes (Livdahl and Willey (1991) Science 253: 189–191), we extensively monitored the abundances of mosquito immatures before and after the Asian Tiger invaded these habitats in south Florida. These field data failed to demonstrate exclusion of A. triseriatus from Treeholes following the establishment of A. albopictus in this microhabitat in 1991. However, A. albopictus had significantly higher metamorphic success and showed a significant increase in mean crowding on A. triseriatus in Treeholes monitored from 1991 to 1999. In urban and suburban sites, A. triseriatus was uncommon in abandoned tires even before the arrival of A. albopictus . In some wooded sites, there is evidence for a decline in numbers of A. triseriatus in used tires and cemetery vases, but the native species has not been excluded from these habitats. Overall, the negative effect of A. albopictus on A. triseriatus has been less severe than that on A. aegypti . Experiments outdoors in surrogate Treeholes showed that A. albopictus was more successful than A. triseriatus in survival to emergence in the presence of predatory larvae of the native mosquito Toxorhynchites rutilus when first instar predators encountered both prey species shortly after their hatch. Eggs of A. albopictus also hatched more rapidly than those of A. triseriatus , giving larvae of the invasive species an initial developmental advantage to escape predation. Biological traits that may favor A. albopictus are offset partly by greater Treehole occupancy by A. triseriatus and the infrequency of the invasive mosquito species in undisturbed woodlands, which mitigates against displacement of the native mosquito in these habitats.
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body size sexual receptivity and larval cannibalism in relation to protandry among toxorhynchites mosquitoes
Oikos, 1996Co-Authors: L. P. Lounibos, D Duzak, R. L. Escher, E A MartinAbstract:Males of Toxorhynchites rutilis and T. amboinensis emerge as adults significantly sooner than females, the difference between sexes more pronounced in the latter species. In contrast to other protandrous mosquitoes, male and female T. rutilus do not differ in mean body mass and T. amboinensis females are only slightly larger than males. Protandry in the context of size similarity of the sexes is maintained by significantly faster growth of males. Sexual maturity is attained in both sexes approximately one day after adult eclosion. which occurs primarily in the late afternoon. Predatory fourth instar T. rutilus that co-occurred in Treeholes were far more similar in body mass than individuals of that same stage that occupied different Treeholes. In surrogate Treeholes set experimentally in nature, the rate of cannibalism was significantly higher among T. rutilus fourth instars that differed in body mass. We propose that the size similarity which minimizes larval cannibalism selects against sexual size dimorphism in adults of these species.
John R. Anderson - One of the best experts on this subject based on the ideXlab platform.
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Vertical Oviposition and Lambornella clarki (Ciliophora: Tetrahymenidae) Dispersal by Aedes sierrensis (Diptera: Culicidae) in California
Journal of vector ecology : journal of the Society for Vector Ecology, 2010Co-Authors: David R. Mercer, Jan O. Washburn, John R. AndersonAbstract:Vertical stratification of Treeholes used by mosquitoes may reflect resource quality or result from interspecific competition. Mosquitoes able to monopolize Treeholes with optimal resources may be over-represented in the community. Aedes sierrensis, which is well adapted for the Mediterranean climate of California, has evolved in the absence of interspecific competition, so oviposition should reflect resource quality to a large extent. Artificial oviposition traps mounted at four canopy heights facing north or south on trees in a mixed-oak forest at four elevations of the Pacific Coastal Range were used to assess vertical ovipositional preferences by the western Treehole mosquito. Natural dispersal of the ciliated protozoan parasite Lambornella clarki was similarly monitored. Gravid Ae. sierrensis showed no vertical stratification during egg laying in traps. Lambornella clarki were naturally dispersed at relatively low frequency into traps and persisted unless eliminated by larval predation. Aedes sierrensis is not currently constrained into occupying a subset of Treeholes. However, invasion of its native range by competitive species may alter oviposition patterns.
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Tannins in Treehole habitats and their effects on Aedes sierrensis (Diptera: Culicidae) production and parasitism by Lambornella clarki (Ciliophora: Tetrahymenidae).
Journal of medical entomology, 1994Co-Authors: David R. Mercer, John R. AndersonAbstract:Tannin concentration, measured as total phenolics, varied widely in natural Treehole water throughout the period of development for Aedes sierrensis (Ludlow), the western Treehole mosquito. Tannic acid induced a parasitic response in free-living populations of the protozoan Lambornella clarki Corliss & Coats, an effect not entirely explained by acidity. Tannic acid concentration influenced mosquito developmental rates, survival, size, and proportion females more than food level, L. clarki parasite exposure, or any interaction of treatments for Ae. sierrensis populations reared in artificial microcosms exposed to natural conditions.
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Parasitism of newly-hatched Aedes sierrensis (Diptera: Culicidae) larvae by Lambornella clarki (Ciliophora: Tetrahymenidae) following habitat flooding.
Journal of invertebrate pathology, 1991Co-Authors: Jan O. Washburn, John R. Anderson, David R. MercerAbstract:Host-parasite interactions between Lambornella clarki (Ciliophora: Tetrahymenidae) and its natural host, Aedes sierrensis (Diptera: Culicidae), were studied in newly flooded Treeholes in northern California between 1986 and 1989. First instar host larvae hatched within 1 to 4 hr of flooding, while free-living trophonts of L. clarki appeared between 7 and 24 hr. As early as 24 hr after flooding, ciliates initiated the first parasite cycle by forming cuticular cysts on first instar larvae; by 64 hr, cysts were observed on larvae collected from all positive holes during all years. While larvae with as many as 12 cysts were observed, most supported only 1 cyst, and successful infections were established by the entry of a single ciliate into the host's hemocoel. Among Treehole populations, the proportion of larvae with L. clarki cysts ranged from 2 to 100% at 48 hr indicating that enzootics and epizootics develop rapidly in newly flooded Treeholes. Average attack rates from all holes by year ranged between 17.0 and 44.4%. Ciliates began entering hosts 48 to 72 hr after flooding, but some larvae escaped parasitization by molting to the second instar before ciliates penetrated the cuticle. In some Treeholes, opportunistic microorganisms entered larvae with the invading ciliates and killed both the host and parasite.
