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Elisabeth M Gross - One of the best experts on this subject based on the ideXlab platform.
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small scale variation in sexual size dimorphism and sex ratio in the aquatic moth acentria Ephemerella denis and schiffermuller 1775 lepidoptera crambidae
Aquatic Insects, 2014Co-Authors: Oliver Miler, Elisabeth M Gross, Dietmar StraileAbstract:The aquatic herbivorous and capital-breeding moth Acentria Ephemerella Denis and Schiffermuller, 1775 feeds on submerged pondweeds, Potamogeton spp., and is highly preyed upon by fish in the littoral zone. We studied the spatiotemporal within-lake variability of length, sexual size dimorphism (SSD) and sex ratio of A. Ephemerella pupae and of larval population densities. Population densities at three sampling sites strongly increased from July to August and were significantly higher at the Reichenau site in July. Acentria Ephemerella sex ratio was male-biased at the Guttingen and Hagnau sites, but showed unbiased or slightly biased sex ratios at Reichenau. The SSD was strongly female-biased. Female size and SSD declined during summer, possibly due to reduced food quantity/quality. The SSD was highest at Reichenau, with little to no differences between Hagnau and Guttingen. At Reichenau, the high population size in July coincided with an unbiased sex ratio, and large SSD/female size due to multiple, possib...
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erratum lau t f s gross e m meyer rochow v b 2007 sexual dimorphism and light dark adaptation in the compound eyes of male and female acentria Ephemerella lepidoptera pyraloidea crambidae eur j entomol 104 3 459 470
European Journal of Entomology, 2013Co-Authors: Ting Fan Lau, Elisabeth M Gross, V B MeyerrochowAbstract:ErratumIn our recent publication:Lau T.F.S., Gross E.M. & Meyer-Rochow V.B. 2007: Sexual dimorphism and light/dark adaptation in the compound eyes of male and female Acentria Ephemerella (Lepidoptera: Pyraloidea: Crambidae). Eur. J. Entomol. 104: 459-470.the referenceSchwind R. 1993: Reflection-polarization pattern at water surfaces and correction of a common representation of the polarization pattern of the sky. Naturwissenschaften 80: 82-83.fails to mention the co-author of that paper and, thus, should have beenSchwind R. & Horvath G. 1993: Reflection-polarization pattern at water surfaces and correction of a common representation of the polarization pattern of the sky. Naturwissenschaften 80: 82-83.We regret this oversight of ours and apologize to the authors.Ting Fan (Stanley) LAU, Elisabeth Maria GROSS and Victor Benno MEYER-ROCHOW
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sexual dimorphism and light dark adaptation in the compound eyes of male and female acentria Ephemerella lepidoptera pyraloidea crambidae
European Journal of Entomology, 2007Co-Authors: Ting Fan Stanley Lau, Elisabeth M Gross, V B MeyerrochowAbstract:In the highly sexual-dimorphic nocturnal moth, Acentria Ephemerella Denis & Schiffermuller 1775, the aquatic and win- gless female possesses a refracting superposition eye, whose gross structural organization agrees with that of the fully-winged male. The possession of an extensive corneal nipple array, a wide clear-zone in combination with a voluminous rhabdom and a reflecting tracheal sheath are proof that the eyes of both sexes are adapted to function in a dimly lit environment. However, the ommatidium of the male eye has statistically significantly longer dioptric structures (i.e., crystalline cones) and light-perceiving elements (i.e., rhab- doms), as well as a much wider clear-zone than the female. Photomechanical changes upon light/dark adaptation in both male and female eyes result in screening pigment translocations that reduce or dilate ommatidial apertures, but because of the larger number of smaller facets of the male eye in combination with the structural differences of dioptric apparatus and retina (see above) the male eye would enjoy superior absolute visual sensitivity under dim conditions and a greater resolving power and ability to detect movement during the day. The arrangement of the microvilli in the rhabdom of both genders suggests that their eyes are polarization-sensitive, an ability they would share with many aquatic insects that have to recognize water surfaces. Although sexual recognition in A. ephe- merella is thought to chiefly rely on pheromones, vision must still be important for both sexes, even if the females are wingless and never leave their watery habitat. Females swim actively under water and like their male counterparts, which fly above the surface of the water, they would have to see and avoid obstacles as well as potential predators. This, together with a small incidence of winged females, we believe, could be the reason why the eyes of female A. Ephemerella are less regressed than those of other sexually dimorphic moths, like for instance Orgyia antiqua. Another, but difficult to test, possibility is that male and female A. Ephemerella have diverged in their behaviour and habitat preferences less long ago than other sexually dimo rphic moths.
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chemical defense in elodea nuttallii reduces feeding and growth of aquatic herbivorous lepidoptera
Journal of Chemical Ecology, 2007Co-Authors: Georg Pohnert, Daniela Erhard, Elisabeth M GrossAbstract:The submersed macrophyte Elodea nuttallii (Hydrocharitaceae) is invasive in Europe and frequently found in aquatic plant communities. Many invertebrate herbivores, such as larvae of the generalist aquatic moth, Acentria Ephemerella (Lepidoptera, Pyralidae), avoid feeding on E. nuttallii and preferably consume native species. First instar larvae exhibited a high mortality on E. nuttallii compared to the native macrophyte Potamogeton perfoliatus. Mortality of older larvae was also high when fed E. nuttallii exposed to high light intensities. Growth of older larvae was strongly reduced on E. nuttallii compared to pondweeds (Potamogeton lucens). Neither differences in nitrogen nor phosphorus content explained the different performance on these submerged macrophytes, but plants differed in their flavonoid content. To investigate whether plant-derived allelochemicals from E. nuttallii affect larval performance in the same way as live plants, we developed a functional bioassay, in which Acentria larvae were reared on artificial diets. We offered larvae Potamogeton leaf disks coated with crude Elodea extracts and partially purified flavonoids. Elodea extracts deterred larvae from feeding on otherwise preferred Potamogeton leaves, and yet, unknown compounds in the extracts reduced growth and survival of Acentria. The flavonoid fraction containing luteolin-7-O-diglucuronide, apigenin-7-O-diglucuronide, and chrysoeriol-7-O-diglucuronide strongly reduced feeding of larvae, but did not increase mortality. The concentrations of these compounds in our assays were 0.01-0.09% of plant dry mass, which is in the lower range of concentrations found in the field (0.02-1.2%). Chemical defense in E. nuttallii thus plays an ecologically relevant role in this aquatic plant-herbivore system.
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high abundance of herbivorous lepidoptera larvae acentria Ephemerella denis schiffermuller on submersed macrophytes in lake constance germany
Archiv Fur Hydrobiologie, 2002Co-Authors: Elisabeth M Gross, Claudia Feldbaum, Claudia ChoiAbstract:Seasonal changes in the abundance of the herbivorous moth larvae Acentria Ephemerella on submersed macrophytes in Lake Constance were studied between 1998 and 2000. Acentria were found feeding on many pondweeds (Potamogeton lucens, P. pectinatus, P. perfoliatus), Ceratophyllum demersum and Myriophyllum spicatum, but not on Chara spp., Najas marina ssp. intermedia or Elodea nuttallii. During the vegetated periods of 1998 and 2000 the abundance of larvae on P. perfoliatus and M. spicatum increased exponentially from approx. 10ind./m 2 to a maximum of 10,000 ind./m 2 or 20-165 ind./g dm. The much lower abundance in 1999 may be a result of the massive flooding of the lake in spring. Our data suggest that at least part of the Acentria population in Lake Constance may have two generations per year. Larvae use predominantly the upper shoot sections during the active feeding period and move to the lower stem sections for winter diapause. Herbivory caused substantial damage especially to the apical meristems of P. perfoliatus and M. spicatum. This study indicates that aquatic shredder-herbivores may have a stronger impact on submersed macrophytes than previously considered.
Hiromi Uno - One of the best experts on this subject based on the ideXlab platform.
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lifetime eurythermy by seasonally matched thermal performance of developmental stages in an annual aquatic insect
Oecologia, 2020Co-Authors: Hiromi Uno, Jonathon H StillmanAbstract:Organisms with annual life cycles are exposed to life stage specific thermal environments across seasons. Seasonal variation in thermal environments can vary across years and among sites. We investigated how organisms with annual life cycles respond to predictable seasonal changes in temperature and unpredictable thermal variation between habitats and years throughout their lives. Field surveys and historical records reveal that the spatially and temporally heterogeneous thermal environments inhabited by the annual mayfly Ephemerella maculata (Ephemerellidae) shift the date for transition to the next, life stage, so that the thermal phenotype of each life stage matches the thermal environment of the specific habitat and year. Laboratory studies of three distinct life stages of this mayfly reveal that life stage transitions are temperature dependent, facilitating timing shifts that are synchronized with the current season's temperatures. Each life stage exhibited specific thermal sensitivity and performance phenotypes that matched the ambient temperature typically experienced during that life stage. Our study across the whole life cycle reveals mechanisms that allow organisms to achieve lifetime eurythermy in a dynamic seasonal environment, despite having narrower thermal ranges for growth and development in each life stage.
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migratory life cycle of Ephemerella maculata traver 1934 ephemerellidae
Aquatic Insects, 2019Co-Authors: Hiromi UnoAbstract:In this paper, I describe for the first time the migratory life cycle of an univoltine mayfly, Ephemerella maculata (Traver, 1934), between mainstems and tributaries of stream networks in Californi...
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Accepted Manuscript
2016Co-Authors: George Poinar, Larissa Walder, Hiromi UnoAbstract:A new nematode, Anomalomermis ephemerophagis n. g., n. sp. (Nematoda: Mermithidae) is described from the mayfly, Ephemerella maculata Traver,1934 (Ephermeroptera: Ephermerellidae), in California. The new species is characterized by 6 cephalic papillae and 4 additional disk papillae located on the head between the cephalic papillae and stoma. Additional diagnostic characters are: mouth opening terminal, absence of X-fibers in the cuticle of both postparasitic juveniles and adults, paired, curved, medium-sized spicules, a straight barrow-shaped vagina and large eggs. Two infectious agents were present in some specimens. This is the first description of an adult nematode from a mayfly. optera
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spatial and temporal linkage of stream riparian food webs by seasonal migration of mayfly Ephemerella maculata
2016Co-Authors: Hiromi UnoAbstract:Author(s): Uno, Hiromi | Advisor(s): Sousa, Wayne P. | Abstract: Stream environments are spatially and temporally heterogeneous. Mainstem rivers are often wide, sunlit, warm and productive, while tributaries are shaded by riparian trees, unproductive, and remain cool in summer. Within mainstem rivers themselves there is substantial spatial heterogeneity in habitat structure and physical conditions, such as water temperature. River environments also change dramatically with season. Organisms that live in the riverine environment respond to and take advantage of such heterogeneous environments by moving between microhabitats or shifting their phenology. I studied the life cycle of a riverine mayfly, Ephemerella maculata (Ephemerellidae), in a northern California river system, its responses to spatial and temporal heterogeneity, and how its movements connect stream and riparian food webs in space and time. I discovered that E. maculata migrates between the mainstem and tributaries of rivers during its life cycle, thereby linking food webs in these two habitats, and enhancing predator growth in unproductive tributaries. The resource subsidy from productive but warm rivers to cool, unproductive tributaries associated with the mayfly migration increase the growth of stenothermic predators like juvenile salmonids in otherwise food-limited, cool thermal refuges, and increase their resilience to future warming. Furthermore, I examined the resilience of E. maculata to changes in water temperature using field surveys and lab rearing experiments. I discovered that different life stages of E. maculata have different thermal responses, and they shift their phenology depending on the water temperature, allowing each life stage to occur in the most desirable thermal condition. Therefore, as long as the natural seasonal pattern of the water temperature is sustained, E. maculata can resist temperature changes by shifting their phenology. Finally, I have shown that thermal spatial heterogeneity of rivers desynchronizes mayfly emergence timing, prolonging the subsidy period to riparian predators, and changing the predators’ responses to this subsidy.
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mainstem tributary linkages by mayfly migration help sustain salmonids in a warming river network
Ecology Letters, 2015Co-Authors: Hiromi Uno, Mary E PowerAbstract:Animal migrations can link ecosystems across space. We discovered an aquatic insect that migrates between a river mainstem and its tributaries, and provides an important trophic subsidy for tributary predators. A mayfly, Ephemerella maculata, rears in a warm, sunlit productive river mainstem, then migrates as adults to cool, shaded unproductive tributaries where they oviposit and die. This migration tripled insect flux into a tributary for 1 month in summer. A manipulative field experiment showed that this E. maculata subsidy nearly tripled the growth of the young of the year steelhead trout (Oncorhynchus mykiss) in the recipient tributary over the summer months, and was more important than terrestrial invertebrate subsidies, which have been considered the primary food source for predators in small, forested creeks. By delivering food subsidies from productive but warming river mainstems to cool but food-limited tributaries, aquatic insect migrations could enhance resilience to cool-water predators in warming river networks.
W P Mccafferty - One of the best experts on this subject based on the ideXlab platform.
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revision of ephemerellidae genera ephemeroptera
Transactions of The American Entomological Society, 2008Co-Authors: Luke M Jacobus, W P MccaffertyAbstract:Abstract The generic classification of Ephemerellidae Klapalek (Ephemeroptera) is reviewed and revised. Taxonomic status quo is maintained for the subfamily Timpanoginae Allen, except that Melanameleus Tiensuu (Ameletidae McCafferty) is not synonymous with Eurylophella Tiensuu. Data from the external morphology of eggs, larvae and adults of Ephemerellinae, s.s., species are coded into a data matrix and analyzed via the parsimony criterion of PAUP* to construct phylogenetic trees. A higher classification of Ephemerellinae is proposed based on the naming of groups from these trees. Two tribes are recognized and redefined: Ephemerellini, s.s., and Hyrtanellini Allen. Ephemerellini contains eleven genera: Drunella Needham [= Eatonella Needham, new synonym; = Myllonella Allen, new synonym; = Tribrochella Allen, new synonym; = Unirhachella Allen, new synonym], Caurinella Allen, Ephemerella Walsh, Matriella, new genus, Tsalia, new genus, Caudatella Edmunds, Notacanthella, new genus, Spinorea, new genus, Adoranex...
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revisionary contributions to north american Ephemerella and serratella ephemeroptera ephemerellidae
Journal of The New York Entomological Society, 2003Co-Authors: Luke M Jacobus, W P MccaffertyAbstract:Abstract The study of population variability and the reexamination of type material of certain Ephemerellidae species has revealed changes in status and new synonyms. Ephemerella dorothea Needham, 1908 [=E. infrequens McDunnough, 1924, new synonym, =E. mollitia Seemann, 1927, new synonym] is divided into two subspecies: E. d. dorothea, new status, and E. d. infrequens new status [=E. mollitia, new synonym]. New synonyms were discovered for the following: Ephemerella excrucians Walsh, 1862 [=E. inermis Eaton, 1884, new synonym, =E. argo Burks, 1947, new synonym, =E. crenula Allen and Edmunds, 1965, new synonym, =E. lacustris Allen and Edmunds, 1965, new synonym, =E. rossi Allen and Edmunds, 1965, new synonym, =E. rama Allen, 1968, new synonym], E. invaria Walker, 1853 [=E. rotunda Morgan, 1911, new synonym, =E. vernalis Banks, 1914, new synonym, =E. feminina Needham, 1924, new synonym, =E. fratercula McDunnough, 1925, new synonym, =E. inconstans Traver, 1932, new synonym, =E. choctawhatchee Berner, 1946, n...
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contribution to the biology and systematics of Ephemerella alleni ephemeroptera ephemerellidae
Pan-pacific Entomologist, 2003Co-Authors: Luke M Jacobus, Boris C Kondratieff, M D Meyer, W P MccaffertyAbstract:The adult stages of the western Nearctic species Ephemerella alleni Jensen & Edmunds are described for the first time based on reared specimens from Mount Rainier National Park, Washington, USA. Male adults are distinguished by having ganglionic marks on the abdominal sterna, genital forceps segment 2 with a distal expansion, penes with short apical projections, and spinulelike setae medially near the outer margin and along the inner margin of the medioapical cleft. Eggs have a smooth chorion. Larvae are distinguished from congeners by having a smooth frons and abdominal terga with distinctive paired spines. Morphological variability in these and other structures can confound identification of single specimens or short series of specimens. Our collection data represent the first new records of the species since its original description in 1966.
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first adult description for Ephemerella hispida ephemeroptera ephemerellidae
Entomological News, 2002Co-Authors: Luke M Jacobus, W P Mccafferty, S SpichigerAbstract:Reared material from Tennessee and South Carolina provide the bases for the first adult description of Ephemerella hispida. Structural characters associated with the male genitalia, such as the number and placement of ventral spines on the penes, differentiate this species from sympatric congeners.
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adult descriptions and commentary for two species of southeastern nearctic Ephemerella ephemeroptera ephemerellidae
Entomological News, 2001Co-Authors: Luke M Jacobus, W P MccaffertyAbstract:Reared and associated materials from Florida and the Great Smoky Mountains provide the bases for the first adult descriptions of Ephemerella choctawhatchee and E. rossi. Male adults of the two species are shown to be morphologically distinctive among congeners, based on characters associated with the male genitalia. The relatively similar larvae of E. choctawhatchee and E. invaria are possibly ecologically and geographically distinct. The first records of E. rossi from Georgia are provided.
Claudia Choi - One of the best experts on this subject based on the ideXlab platform.
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high abundance of herbivorous lepidoptera larvae acentria Ephemerella denis schiffermuller on submersed macrophytes in lake constance germany
Archiv Fur Hydrobiologie, 2002Co-Authors: Elisabeth M Gross, Claudia Feldbaum, Claudia ChoiAbstract:Seasonal changes in the abundance of the herbivorous moth larvae Acentria Ephemerella on submersed macrophytes in Lake Constance were studied between 1998 and 2000. Acentria were found feeding on many pondweeds (Potamogeton lucens, P. pectinatus, P. perfoliatus), Ceratophyllum demersum and Myriophyllum spicatum, but not on Chara spp., Najas marina ssp. intermedia or Elodea nuttallii. During the vegetated periods of 1998 and 2000 the abundance of larvae on P. perfoliatus and M. spicatum increased exponentially from approx. 10ind./m 2 to a maximum of 10,000 ind./m 2 or 20-165 ind./g dm. The much lower abundance in 1999 may be a result of the massive flooding of the lake in spring. Our data suggest that at least part of the Acentria population in Lake Constance may have two generations per year. Larvae use predominantly the upper shoot sections during the active feeding period and move to the lower stem sections for winter diapause. Herbivory caused substantial damage especially to the apical meristems of P. perfoliatus and M. spicatum. This study indicates that aquatic shredder-herbivores may have a stronger impact on submersed macrophytes than previously considered.
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impact of polyphenols on growth of the aquatic herbivore acentria Ephemerella
Journal of Chemical Ecology, 2002Co-Authors: Claudia Choi, Oliver Walenciak, Christa Bareiss, Elisabeth M GrossAbstract:Larvae of Acentria Ephemerella live fully submerged, feeding on submersed aquatic angiosperms such as pondweeds (Potamogeton spp.) and Myriophyllum spicatum. Only the latter contains high concentrations of hydrolyzable tannins known to interfere with the growth of insect herbivores. We tested whether larvae grow faster on Potamogeton perfoliatus or M. spicatum and whether this is due to polyphenols in their food source. Larvae originating from the same egg clutch grew faster and larger on P. perfoliatus than on M. spicatum. The same growth response was observed with larvae that spent winter diapause on either P. perfoliatus or M. spicatum. These larvae were fed either with their host plant or the other macrophyte. No prior feeding effect was found, but growth of larvae reared on M. spicatum was less than when grown on P. perfoliatus. Larvae from another egg-clutch reared on M. spicatum, either from lake or cultivated in aquaria, exhibited reduced growth on the lake plants. P. perfoliatus contained less than 1% and M. spicatum (aquarium or field material) between 5 and 9% phenolic compounds. No differences in nitrogen content of leaves were found, but apical shoot sections of M. spicatum exhibited a significantly higher nitrogen content than P. perfoliatus. Our results indicate that hydrolyzable tannins are responsible for the reduced growth of Acentria when fed with M. spicatum.
Oliver Walenciak - One of the best experts on this subject based on the ideXlab platform.
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impact of polyphenols on growth of the aquatic herbivore acentria Ephemerella
Journal of Chemical Ecology, 2002Co-Authors: Claudia Choi, Oliver Walenciak, Christa Bareiss, Elisabeth M GrossAbstract:Larvae of Acentria Ephemerella live fully submerged, feeding on submersed aquatic angiosperms such as pondweeds (Potamogeton spp.) and Myriophyllum spicatum. Only the latter contains high concentrations of hydrolyzable tannins known to interfere with the growth of insect herbivores. We tested whether larvae grow faster on Potamogeton perfoliatus or M. spicatum and whether this is due to polyphenols in their food source. Larvae originating from the same egg clutch grew faster and larger on P. perfoliatus than on M. spicatum. The same growth response was observed with larvae that spent winter diapause on either P. perfoliatus or M. spicatum. These larvae were fed either with their host plant or the other macrophyte. No prior feeding effect was found, but growth of larvae reared on M. spicatum was less than when grown on P. perfoliatus. Larvae from another egg-clutch reared on M. spicatum, either from lake or cultivated in aquaria, exhibited reduced growth on the lake plants. P. perfoliatus contained less than 1% and M. spicatum (aquarium or field material) between 5 and 9% phenolic compounds. No differences in nitrogen content of leaves were found, but apical shoot sections of M. spicatum exhibited a significantly higher nitrogen content than P. perfoliatus. Our results indicate that hydrolyzable tannins are responsible for the reduced growth of Acentria when fed with M. spicatum.
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influence of myriophyllum spicatum derived tannins on gut microbiota of its herbivore acentria Ephemerella
Journal of Chemical Ecology, 2002Co-Authors: Oliver Walenciak, Walter Zwisler, Elisabeth M GrossAbstract:The submerged living larvae of Acentria Ephemerella were fed in the laboratory with either M. spicatum or Potamogeton perfoliatus, two of their host plants. Larvae exhibited a reduced growth when fed M. spicatum, a freshwater angiosperm that contains high concentrations of tannins, secondary metabolites known for their herbivore-deterrent and antimicrobial properties. In this study, we investigated the influence of food-derived tannins on gut microbiota. Bacterial densities in the guts did not differ between the food regimes, ranging from 2.8 to 13.3 × 106cells per gut. Gut bacteria were characterized with cultivation techniques and subsequent identification of the strains by molecular methods. We isolated 17 bacterial strains belonging to all subdivisions, i.e., we identified α-, β- and γ-proteobacteria, Cytophyaga/Flavobacteria (CF) and several Gram-positive bacteria. All except one Gram-positive strain were found in the guts of larvae fed with P. perfoliatus. Gram-positive bacteria and bacteria of the CF cluster were more sensitive to polyphenol-containing extracts of M. spicatum in an agar diffusion assay than strains of the α- or γ-proteobacteria subdivision. Our results suggest an influence of food-derived tannins on gut microbiota in A. Ephemerella.