21,933 research outputs found

    An Overview of the Heteroptera of Illinois

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    A key to adults of all heteropteran families known to occur in Illinois is presented together with general information on the biologies of these families. Also included are general references on Heteroptera and on individual families, particularly if those references involve studies of fauna that were conducted in Illinois, adjacent states, or nearby parts of Canada

    Descriptions of Nymphal Instars of \u3ci\u3eAbedus Breviceps\u3c/i\u3e (Hemiptera: Belostomatidae)

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    The 1st-5th instars of Abedus breviceps Still, collected from a Texas population, are described and illustrated. They can be separated most easily by overall body length and width, and by the length of the mesonotal wing pads

    Life History and Laboratory Rearing of \u3ci\u3eCorythucha Juglandis\u3c/i\u3e (Hemiptera: Tingidae) With Descriptions of Immature Stages

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    The life history of Corythucha juglandis was investigated in Jackson and Alexander counties. Illinois. August 1981-December 1985 and the immature stages were described. The bug was also raised from egg to adult under controlled laboratory conditions. This apparently bivoltine species overwintered as adults that became active in late April-early May. began feeding on the undersides of black walnut leaflets, and reproduced shortly thereafter. The seasonal occurrence of the adults and subsequent immature stages is discussed. Adults were last observed in mid-October. C. juglandis was reared on black walnut leaflets under a 16L:8D photoperiod at ca. 23.9°C. The pre-ovipositional, ovipositionaL and post-ovipositional periods averaged 14.0, 50.3, and 11.9 days, respectively: average fecundity was 118.6. The incubation period, and 1st, 2nd, 3rd, 4th, and 5th stadia averaged 16.4,4.3,3.8,4.2,4.6, and 6.7 days, respectively

    New Larval Descriptions and Comparisons of North American \u3ci\u3eChoroterpes\u3c/i\u3e (Ephemeroptera: Leptophlebiidae)

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    Formal descriptions of larvae of the western North American species Choroterpes albiannulata and the eastern North American species Choroterpes fusca (Ephemeroptera: Leptophlebiidae) are given for the first time. Specimens, including reared adult and larval associations, of C. albiannulata were available from Nevada, Oregon, and Idaho, and rearings of C. fusca were made from the Huron Mountains in the Upper Peninsula of Michigan. Six of the nine species of North American Choroterpes (subgenus Choroterpes) are now known as larvae. Larval characteristics are compared, particularly with regard to similarities and differences between C. albiannulata and C. fusca, c. albiannulata and the western C. inornata. and C. fusca and the eastern C. basalis. Choroterpes albiannulata is distinct but shares gill morphology with C. inornata. Choroterpes fusca is quite similar to C. basalis, sharing . morphology and color patterning, but with some apparent differences that may prove to be consistent. Certain Choroterpes larvae from Arkansas are probably C. oklahomae (known only as adults from Oklahoma) but cannot be associated at this time. Distributions of species of subgenus Choroterpes are updated, and a revision of the entire genus based on cladistic analysis is recommended

    Digital dissection of the model organism Xenopus laevis using contrast-enhanced computed tomography

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    The African clawed frog, Xenopus laevis, is one of the most widely used model organisms in biological research. However, the most recent anatomical description of X. laevis was produced nearly a century ago. Compared with other anurans, pipid frogs – including X. laevis – exhibit numerous unusual morphological features; thus, anatomical descriptions of more ‘typical’ frogs do not detail many aspects of X. laevis skeletal and soft‐tissue morphology. The relatively new method of using iodine‐based agents to stain soft tissues prior to high‐resolution X‐ray imaging has several advantages over gross dissection, such as enabling dissection of very small and fragile specimens, and preserving the three‐dimensional topology of anatomical structures. Here, we use contrast‐enhanced computed tomography to produce a high‐resolution three‐dimensional digital dissection of a post‐metamorphic X. laevis to successfully visualize: skeletal and muscular anatomy; the nervous, respiratory, digestive, excretory and reproductive systems; and the major sense organs. Our digital dissection updates and supplements previous anatomical descriptions of this key model organism, and we present the three‐dimensional data as interactive portable document format (PDF) files that are easily accessible and freely available for research and educational purposes. The data presented here hold enormous potential for applications beyond descriptive purposes, particularly for biological researchers using this taxon as a model organism, comparative anatomy and biomechanical modelling

    Development of kelp rockfish, Sebastes atrovirens (Jordan and Gilbert 1880), and brown rockfish, S. auriculatus (Girard 1854), from birth to pelagic juvenile stage, with notes on early larval development of black-and-yellow rockfish, S. chrysomelas (Jordan and Gilbert 1880), reared in the laboratory (Pisces: Sebastidae).

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    Larval kelp (Sebastes atrovirens), brown (S. auriculatus), and blackand-yellow (S. chrysomelas) rockfish were reared from known adults, to preflexion stage, nine days after birth for S. chrysomelas, to late postflexion stage for S. atrovirens, and to pelagic juvenile stage for S. auriculatus. Larval S. atrovirens and S. chrysomelas were about 4.6 mm body length (BL) and S. auriculatus about 5.2 mm BL at birth. Both S. atrovirens and S. auriculatus underwent notochord flexion at about 6–9 mm BL. Sebastes atrovirens transform to the pelagic juvenile stage at about 14–16 mm BL and S. auriculatus transformed at ca. 25 mm BL. Early larvae of all three species were characterized by melanistic pigment dorsally on the head, on the gut, on most of the ventral margin of the tail, and in a long series on the dorsal margin of the tail. Larval S. atrovirens and S. auriculatus developed a posterior bar on the tail during the flexion or postflexion stage. In S. atrovirens xanthic pigment resembled the melanistic pattern throughout larval development. Larval S. auriculatus lacked xanthophores except on the head until late preflexion stage, when a pattern much like the melanophore pattern gradually developed. Larval S. chrysomelas had extensive xanthic pigmentation dorsally, but none ventrally, in preflexion stage. All members of the Sebastes subgenus Pteropodus (S. atrovirens, S. auriculatus, S. carnatus, S. caurinus, S. chrysomelas, S. dalli, S. maliger, S. nebulosus, S. rastrelliger) are morphologically similar and all share the basic melanistic pigment pattern described here. Although the three species reared in this study can be distinguished on the basis of xanthic pigmentation, it seems unlikely that it will be possible to reliably identify field-collected larvae to species using traditional morphological and melanistic pigmentation characters. (PDF file contains 36 pages.

    Life History and Laboratory Rearing of \u3ci\u3eGerris Argenticollis\u3c/i\u3e (Hemiptera: Gerridae) with Descriptions of Immature Stages

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    The life history of Gerris argenticollis was investigated in Jackson County, Illinois, March-June 1986, and the immature stages were described. The water strider also was reared from egg to adult under laboratory conditions. This univoltine species overwintered as adults that became active in early March, appearing on a temporary woodland pond after the air temperature exceeded 12°C. Seasonal occurrence of the adults and immatures is discussed. Adults were last observed in mid-June. Feeding records are given. G. argenticollis was reared on Drosophila melanogaster adults under a 10L: 14D photoperiod (ca. 2800 lux) at ca. 21°C. The incubation period averaged 12.5 days. The average durations of the five nymphal stadia were 9.0, 7.6, 8.0, 9.2, and 12.0 days. The total developmental period averaged 58.3 days

    Barbaetis: A New Genus of Eastern Nearctic Mayflies (Ephemeroptera: Baetidae)

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    The new genus Barbaetis Waltz and McCafferty, and new species Barbaetis benfieldi Kennedy are described from larvae collected from the New River, Virginia. Barbaetis is easily told from Baetis by the presence of procoxal osmobranchia. Cladistics of B. benfieldi, related Pseudocloeon species, and the lutheri and pavidus complexes of Baetis are presented and indicate the need for further taxonomic revision. The habitat of B. benfieldi is described in terms of several ecological parameters. The new species demonstrates a univoltine life history with postembryonic development restricted to a short springtime period
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