Showing papers on "Larva published in 1983"
TL;DR: In this system community structure is affected by a gape-limited predator, Notophthalmus, that acts early in the anuran larval period, probably before competition occurs, which means the survivors of predation probably have enhanced success as terrestrial juveniles compared to the sur- vivors of competition in communities where there is a low risk ofpredation.
Abstract: Replicated pond communities were established in 27 tanks 1.52 m in diameter and 0.62 m deep. The communities included a sample from a pooled mixture of zooplankton from nine small ponds, 20 stems of the aquatic perennial Myriophyllum heterophyllum, and 300 hatchlings of the toad Bujo woodhousei fowleri. All nine combinations of three densities of a predator (0, 4, or 8 adult Notophthalmus viridescens in an equal sex ratio) and three densities of prey (larvae of the frogs: Rana sphenocephala, Bufo terrestris, and Scaphiopus holbrooki, in constant relative abundance) were randomly represented in each of three blocks arranged in a Graeco-Latin square design. In the absence of predators, the anurans had density-dependent survival, lengths of larval period, and sizes at metamorphosis. There was evidence of competition among, as well as within, species. Rana sphenocephala had wintering tadpoles only in the highest-density populations. In this system community structure is affected by a gape-limited predator, Notophthalmus, that acts early in the anuran larval period, probably before competition occurs. In the presence of Notophthalmus all anurans had low survival, large mean size at metamorphosis, and short mean larval period. The survivors of predation probably have enhanced success as terrestrial juveniles compared to the sur- vivors of competition in communities where there is a low risk of predation.
145 citations
TL;DR: Both a higher rate of growth and longer duration of larval development contribute to the larger adult size of females than males.
43 citations
TL;DR: The high tolerance of the midge larva to acute Cadmium exposure was not explainable by induction of the cadmium-binding proteins and this protein was a mixture of four isoproteins and showed the characteristic properties of metallothionein.
42 citations
TL;DR: Calculated durations of different developmental stages starting on each day of the year and the period in which pupal diapause is necessary were consistent with light-trap data and other observations published elsewhere.
Abstract: Previously published information on effects of constant temperatures on development by Heliothis spp. was used with long-term temperature records for the Namoi Valley to calculate the durations of different developmental stages starting on each day of the year. Calculations of the number of generations per year and the period in which pupal diapause is necessary were consistent with light-trap data and other observations published elsewhere. A figure showing times taken from oviposition to egg hatch and to one third-grown larva in different months indicates numbers of days available after oviposition in which insecticides must be applied for maximum effect.
23 citations
01 Jan 1983
20 citations
TL;DR: Ophiodromus flexuosus is an important faunal element of the polluted Oslofjord, but its life history was previously unknown and a complete series of developmental stages is illustrated and described based on wild-caught planktonic and benthic larvae and larvae reared in the laboratory.
Abstract: Ophiodromus flexuosus is an important faunal element of the polluted Oslofjord, but its life history was previously unknown. A complete series of developmental stages is illustrated and described based on wild-caught planktonic and benthic larvae and larvae reared in the laboratory. Ophiodromus flexuosus carries 20 000 eggs (O= 108 µm) and spawns in autumn. Larval development is planktotrophic for 1–2 months. The benthic larva grows c. 1 segment per month and increases from c. 0.5 mm (young bottom living larva) to 2–3 mm (juvenile) in the first year. A further year of growth elapses before spawning takes place. After spawning the adult starts to produce new genital products. The larvae can be separated from other hesionids by their red eyes and lack of ventral cirri on the second and third segments. They have fewer segments in relation to their length than other hesionid larvae from Oslofjorden. The presence of only 1–2 capillary setae without spines on each segment separates Ophiodromus flexuosus larvae ...
16 citations
TL;DR: Larvae of the red-backed alder sawfly in all instars except the last, exhibit external accumulations of wax, and one feature peculiar to cuticle lining the craters is the presence of vast numbers of epicuticular filaments which may represent channels for the transport of wax.
Abstract: Larvae of the red-backed alder sawfly, Eriocampa ovata, in all instars except the last, exhibit external accumulations of wax. Approximately 93% of the hexane-extractable wax consists of primary al...
16 citations
TL;DR: Rate of growth of larvae was constant between 2 and 10 DAI followed by a period of rapid growth from 10 to 16 DAI and Nematodes were largely restricted to the first 6 m of gut with 71% of worms occurring in the first 3 m.
13 citations
TL;DR: It is the first time the adult stage in this genus has been reared, and the first record in the Western Hemisphere of a species of Callidosoma from a geometrid.
Abstract: A new species of erythraeid mite, Callidosoma metzi , is described. As a larva, this mite is parasitic on adults of Anacamptodes vellivolata (Hulst) and some other geometrids, and as a deutonymph and adult, it is predaceous on eggs of Lepidoptera. The following stages are described: larva, pupa I, deutonymph, pupa II, and adult. The stages other than larva were reared in the laboratory. It is the first time the adult stage in this genus has been reared, and the first record in the Western Hemisphere of a species of Callidosoma from a geometrid.
12 citations
TL;DR: Analysis of the host-vector cycles of the agents in the particular zones enables appropriate control measures to be devised and in endemic areas this would involve importation and vaccination of introduced animals at the appropriate time.
Abstract: The disease agents under discussion include viruses and protozoans that undergo a cycle in animals as hosts and in insects as vectors. Such agents are found in climatic zones ranging from tropical rains to cool. Outside the tropical rain forests there are periods during which conditions are unsuitable for the cycle of infection to continue, because the activity of the insects is inhibited at temperatures above 35 °C and below 15 °C. During this ‘overwintering’ period the virus may survive by persistence in the host, or in the adult insect, larva or egg, or the virus may be introduced or reintroduced into the area by movement or migration of the host or by carriage of infected insects on the wind. Examples are given of the introduction of disease or infection by insects carried on the wind. Such examples include (i) between the southerly and northerly limits of the Inter-Tropical Convergence Zone, the wind carriage or possible wind carriage of insects infected with bluetongue or yellow fever in West Africa and Sudan and with Rift Valley fever in Egypt, (ii) the wind carriage of midges infected with bluetongue in the eastern Mediterranean and (iii) the introduction of Japanese encephalitis to Japan on monsoon winds by infected mosquitoes. Analysis of the host-vector cycles of the agents in the particular zones enables appropriate control measures to be devised. In endemic areas this would involve importation and vaccination of introduced animals at the appropriate time. In epidemic and sporadic areas, the uncertainty of the timing of outbreaks has to be recognized and the times of breeding of animals and the need for vaccination of animals assessed. During an epidemic the questions of eliminating insect breeding sites, and dipping and spraying of animals have to be considered in relation to possible reintroduction of infection at a later date.
11 citations
TL;DR: The purpose here is to call attention to another extraordinary ability of this larva: the capture of bombardier beetles.
Abstract: While collecting bombardier beetles (Brachinus spp.) on the evening of August 27, 1982, by a pond near Portal, Cochise County, Arizona, a group of us, including Rodger Jackman of the British Broadcasting Corporation and Maria Eisner, came upon an unusual phenomenon. Thousands of young adults of the spadefoot toad, Scaphiopus multiplicatus, were active beside the pond on that night, having just emerged from the water after metamorphosis. On close observation we noted a number of these toads that were dead or dying and in various stages of partial submergence in the mud. Each had been grasped from beneath by a larva of the horsefly Tabanus punct([’er, a mud-dwelling predator, which had seized it with its hooked mouthparts, had pulled it partly into the substrate, and was embibing its body fluids. Details of this first known occurrence of predation by a fly larva on an adult amphibian will be published elsewhere. Our purpose here is to call attention to another extraordinary ability of this larva: the capture of bombardier beetles. We transported several of the larvae to our Cornell laboratories and established them individually in mud-filled enclosures, where they quickly buried themselves, leaving only their mouthparts exposed at the surface (Fig. A). We maintained the larvae on young spadefoot toads, which they captured as they had in the field, and also on insects, which judging from published accounts on tabanid larvae (Webb and Wells, 1924; Oldroyd, 1964; Burger, 1977), must be a principal staple of their diet. They proved capable even of capturing large crickets (Teleogryllus oceanicus), which they hooked by a leg, drew partly into the mud, and then held for hours while sucking out their body contents.
TL;DR: The mechanism through which the brain controls the secretion of diapause hormone from the suboesophageal ganglion can be modified by photoperiodic conditions during the larval stages.
TL;DR: The Anaphrotenia larva stands out as the most plesiomorphic chironomid larva as yet known; and it comes probably rather close to the larva of the dipteran ancestor.
Abstract: Two as yet unknown larvae of the circum-Antarctic subfamily Aphroteniinae, one belonging to Paraphrotenia cf. excellens Brundin, the other representing the new genus and species Anaphrotenia lacustis, are described. While the other members of the subfamily are confined to mountain streams, the larva of anaphrotenia has been found in the littoral zone of a shallow subtropical lake on Fraser Island off the coast of Queensland. Besides some peculiar specializations this larva attracts interest because of the primitive construction of the head capsule where the genae ventrally are widely separated and the wide medial interspace is occupied by a longitudinal postmental plate that is not fused with the genal margins. In these respects the Anaphrotenia larva stands out as the most plesiomorphic chironomid larva as yet known; and it comes probably rather close to the larva of the dipteran ancestor. With its closed head capsule and specialized mouth parts the predatory Paraphrotenia larva appears much more apomorphic. But it retains several comparatively plesiomorphous characters, and among the predatory species of the chironomid larvae it represents a very remarkable type. In both genera the crop is developed as a diverticulum from the oesophagus. The presence of a special, sac-like grinding mill at the caudal end of the crop in both genera seems to be unique. — The paper ends with a discussion on a comparative basis of some aphrotenian larval characters and their anagenetic status. Special attention is paid to the mentum and the development of ventromental and dorsomental teeth within Chironomidae. Also discussed is the independent development of predatory habits and their combination with special morphological traits within different monophyletic groups. Of special interest is the comparatively late occurrence of such habits and corresponding morphological traits high up in the chironomid hierarchy within the Harnischia-group, a phenomenon that is believed to be a case of evolutionary reversal.
TL;DR: Larvae of Stilpnonotus postsignatus Fairmaire, 1889 were collected inside a hard log in Peruibe, Sao Paulo, Brazil; reared adults were identified.
Abstract: Larvae of Stilpnonotus postsignatus Fairmaire, 1889 were collected inside a hard log in Peruibe, Sao Paulo, Brazil; reared adults were identified. A description of the larva, pre-pupa and pupa are provided with ilustrations.
TL;DR: The larva of Melanotus indistinctus Quate is described and characters that distinguish the larva from those of other known species of MelAnotus are discussed and illustrated.
Abstract: The larva of Melanotus indistinctus Quate is described. Characters that distinguish the larva from those of other known species of Melanotus are discussed and illustrated, and the larva is incorporated into an existing key.
TL;DR: Comparison of the life cycle of C. mansioni with life cycles of other Habronemid Nematodes parasitizing birds, points out an evolution of larvae from primitive forms of large size and slow development to evolved forms of small size and rapid development.
Abstract: A habronemid nematode in birds of prey, Milvus migrans Bonaparti and Accipiter badius Linne, in Togo, is identified as Cyrnea (Procyrnea) mansioni (Seurat, 1914). Larval development is experimentally studied in the orthopteran Acrididae Tylotropidius patagiatus Karsch. The first three larval stages are described and illustrated. The biology of this spiruroid nematode is distinguished by the unusual rapidity of larval development (infective larvae at 10 days). Comparison of the life cycle of C. mansioni with life cycles of other Habronemid Nematodes parasitizing birds, points out an evolution of larvae from primitive forms of large size and slow development to evolved forms of small size and rapid development. Observations concerning the encapsulation of infective larvae in the intermediate host confirm this larval evolution.
TL;DR: The larval morphology of Agabus striolatus (Gyllenhal, 1808) is described from specimens from the Netherlands and Sweden and information is given on the natural history and characters are presented for the separation of this larva from other described larvae of European Agabus.
Abstract: The larval morphology of Agabus striolatus (Gyllenhal, 1808) is described from specimens from the Netherlands and Sweden. Descriptions are given of all three larval instars based on specimens taken together with adults. Information is given on the natural history of the species and characters are presented for the separation of this larva from other described larvae of European Agabus.
TL;DR: Larva of Coelambus novemlineatus is very similar to that of C. marklini (Gyllenhal), both being characterized by the presence of swimming hairs on tibiae and tarsi in combination with long cerci that only have seven primary setae.
Abstract: Descriptions are given of all three larval instars of Coelambus novemlineatus (Stephens, 1829) based on reared specimens from northern Sweden. A key to third‐instar larvae of six European species of Coelambus is provided. Larva of C. novemlineatus is very similar to that of C. marklini (Gyllenhal), both being characterized by the presence of swimming hairs on tibiae and tarsi in combination with long cerci that only have seven primary setae. In addition, information is offered on the distribution and habitat of the species.
01 Jan 1983
TL;DR: This document summarizes current capabilities, research and operational priorities, and plans for further studies that were established at the 2015 USGS workshop on quantitative hazard assessments of earthquake-triggered landsliding and liquefaction.
Abstract: ........................................................v
Journal Article•
01 Jan 1983
TL;DR: There was a significant difference in the weight and longevity of female flies treated, at the third larval instar stage, with different doses of malathion, and a similar weight difference was noted between pupae treated at the larval stage.
Abstract: The effects of sub-lethal doses of malathion on the weight, fecundity and longevity of Ischiodon
scutellaris Fabr. were studied. The LDso values for malathion, applied topically to the third instar larvae,
were 26.9 X 10-2 (24h) and 18.7 x 10-2 (48h) /lg/larva; the LD9S values were 146 X 10-2 (24h) and
127.6 X 10-2 (48h) /lg/larva.
There was a significant difference (at 5% level) in the weight and longevity of female flies treated,
at the third larval instar stage, with different doses of malathion. A similar weight difference (at 5% level)
was noted between pupae treated at the larval stage.
Measurable latent toxicity was evident for malathion. The LDso for direct toxicity was 41.7 X
10- 2 /lg/larva and for total toxicity it was 21.4 X 10-2 /lg/larva.