REARING OF TRICHOSIROCALUS HORRIDUS (COLEOPTERA: CURCULIONIDAE) LARVAE IN ARTIFICIAL DIETS

1987 ◽  
Vol 22 (4) ◽  
pp. 330-335 ◽  
Author(s):  
Thomas J. McAvoy ◽  
Loke-Tuck Kok

Diet components of an initially acceptable diet for larvae of Trichosirocalus horridus (Panzer), an introduced weevil for thistle control, Carduus thoermeri Weinmann and C. acanthoides L., were systematically varied to determine if the yield of adult weevils could be improved. A total of 56 new diets were prepared and tested. Survival to the late third instar was slightly improved up to 39%, while larval development improved with additions of Vandersant Vitamin Supplement (8 g per 425 ml batch of diet), lyophilized thistle roots, ergosterol, or by transferring larvae to identical fresh diets after 4 weeks. However, larval survival decreased when excessive casein hydrolysate or 7-dehydrocholesterol was used. Sucrose did not improve larval growth. Of the six new diets that supported complete larval development, one diet yielded two adults, while the other five yielded one adult each. Only one of the diet-reared females oviposited eggs, and longevity of diet-reared adults was shorter than adults reared from its natural host, musk thistle.

1965 ◽  
Vol 13 (1) ◽  
pp. 1 ◽  
Author(s):  
DT Anderson

Embryonic development in I. quadrivalvis follows the typical cirripede pattern except for modifications of cleavage and of development of the gut, associated with a large yolky egg. The nauplius is free-swimming but lecithotrophic. It does not grow, and moults irregularly. The development of cypris features begins precociously and the second half of naupliar life is demersal. The cypris stage is unmodified. Settling was not observed. The maxillary segments develop as a delayed continuation of the naupliar segmental sequence, the thoracic segments from a growth zone of seven ectoteloblasts and eight mesoteloblasts. Each row of eight cells budded from the mesoteloblasts develops into the paired somites of a segment. The midgut develops independently of the yolk cells. In cirripedes, increased yolk results in modification of cleavage and gut development but otherwise has little influence on embryonic development. Larval modifications associated with lecithotrophy promote direct development of the cypris but do not include modification of the cypris. Irregularity of moulting is associated with lack of larval growth. Relative brood sizes suggest that increased yolk in cirripedes offers advantages in larval survival. Post-naupliar segment formation in cirripedes resembles in detail that of Malacostraca, indicating a possible phylogenetic affinity between Malacostraca and Maxillopoda which can be tested by further studies on segment formation in non- Malacostraca.


2020 ◽  
Vol 650 ◽  
pp. 289-308 ◽  
Author(s):  
V Raya ◽  
J Salat ◽  
A Sabatés

This work develops a new method, the box-balance model (BBM), to assess the role of hydrodynamic structures in the survival of fish larvae. The BBM was applied in the northwest Mediterranean to field data, on 2 small pelagic fish species whose larvae coexist in summer: Engraulis encrasicolus, a dominant species, and Sardinella aurita, which is expanding northwards in relation to sea warming. The BBM allows one to quantify the contribution of circulation, with significant mesoscale activity, to the survival of fish larvae, clearly separating the effect of transport from biological factors. It is based on comparing the larval abundances at age found in local target areas, associated with the mesoscale structures (boxes), to those predicted by the overall mortality rate of the population in the region. The application of the BBM reveals that dispersion/retention by hydrodynamic structures favours the survival of E. encrasicolus larvae. In addition, since larval growth and mortality rates of the species are required parameters for application of the BBM, we present their estimates for S. aurita in the region for the first time. Although growth and mortality rates found for S. aurita are both higher than for E. encrasicolus, their combined effect confers a lower survival to S. aurita larvae. Thus, although the warming trend in the region would contribute to the expansion of the fast-growing species S. aurita, we can confirm that E. encrasicolus is well established, with a better adapted survival strategy.


Author(s):  
Cynthia D. Trowbridge

The stenophagous ascoglossan (=sacoglossan) opisthobranch Elysia viridis has long been a model organism for the study of endosymbiosis or kleptoplasty as well as one of the few herbivores to consume the introduced green macroalga Codium fragile on European shores. Larval and post-larval dynamics of the ascoglossan were investigated. Planktotrophic larvae of E. viridis grew at 5–10 μm d−1 (shell length) at 15°C on a unicellular algal diet (the cryptophyte Rhodomonas baltica); larvae became competent one month post-hatching. Effective feeding and chloroplast acquisition typically started within 2–3 d of metamorphosis. Slugs grew about 8 mm in the first month of post-larval life. During this period, juveniles held in the light did not grow faster or survive better than conspecifics held in the dark; thus, functional kleptoplasty did not occur during first three weeks of benthic life. While larval growth rates and the nature of metamorphic cues are consistent with those of many other opisthobranch species with planktotrophic larvae, measures of post-larval growth—particularly as it pertains to kleptoplasty—is a new contribution to opisthobranch biology.


Genetics ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 227-237 ◽  
Author(s):  
Lowell Y M Rayburn ◽  
Holly C Gooding ◽  
Semil P Choksi ◽  
Dhea Maloney ◽  
Ambrose R Kidd ◽  
...  

Abstract Biosynthesis of most peptide hormones and neuropeptides requires proteolytic excision of the active peptide from inactive proprotein precursors, an activity carried out by subtilisin-like proprotein convertases (SPCs) in constitutive or regulated secretory pathways. The Drosophila amontillado (amon) gene encodes a homolog of the mammalian PC2 protein, an SPC that functions in the regulated secretory pathway in neuroendocrine tissues. We have identified amon mutants by isolating ethylmethanesulfonate (EMS)-induced lethal and visible mutations that define two complementation groups in the amon interval at 97D1 of the third chromosome. DNA sequencing identified the amon complementation group and the DNA sequence change for each of the nine amon alleles isolated. amon mutants display partial embryonic lethality, are defective in larval growth, and arrest during the first to second instar larval molt. Mutant larvae can be rescued by heat-shock-induced expression of the amon protein. Rescued larvae arrest at the subsequent larval molt, suggesting that amon is also required for the second to third instar larval molt. Our data indicate that the amon proprotein convertase is required during embryogenesis and larval development in Drosophila and support the hypothesis that AMON acts to proteolytically process peptide hormones that regulate hatching, larval growth, and larval ecdysis.


Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 225
Author(s):  
Stephen Seaton ◽  
George Matusick ◽  
Giles Hardy

The attack patterns, infestation success and larval development of woodborers within living trees are complex and are largely shaped by host tree characteristics. Following a severe drought in a native eucalypt forest where outbreak densities of a native Australian beetle, the eucalyptus longhorned borer (Phoracantha semipunctata), occurred, a tree dissection study was conducted in Australia. This involved felling 40 trees each of jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) that were cut into 1-m sections and neonate larval galleries, larvae in pupal cells and adult borer emergence were measured and added to give total numbers per tree to determine the within-tree distribution and survival of P. semipunctata. There was a significant impact on larval survival in both species, in contrast, pupal survival remained high. Within-tree distribution of P. semipunctata was directional with borer emergence and incidence of larval galleries both negatively associated with tree section height above the ground and positively associated with section diameter and bark thickness, reaching a maximum towards the base of trees. High incidence and survival in lower thicker tree sections indicate a more conducive environment for larval development, in contrast to poor larval survival in smaller thinner sections at the top of trees. The dependence of larval survival on tree characteristics controlling the within-tree distribution of borer emergence is emphasized, and needs to be considered when estimating the spread of borer populations during outbreaks.


2005 ◽  
Vol 3 (3) ◽  
pp. 319-328 ◽  
Author(s):  
Sandra E. Favorito ◽  
Angela M. Zanata ◽  
Maria I. Assumpção

Synbranchus lampreia, new species, is described from rio Goiapi, Marajó Island, Pará, northern Brazil. It differs from the other two described species of the genus by its color pattern, which consists of large roundish black blotches scattered over a light brown or yellowish ground pigmentation and presence of inconspicuous brown small spots distributed among the large dark spots. The species is further distinguished from S. marmoratus by a higher number of vertebrae and from S. madeira by a shorter postanal length. Information about reproductive aspects is provided and larval stages are described and illustrated.


1984 ◽  
Vol 39 (6) ◽  
pp. 553-558 ◽  
Author(s):  
Michael Wink

Polyphagous molluscs such as Helix pomatia and Arion rufus generally do not feed on plants containing alkaloids. Of 19 species tested 10 species were totally avoided, the other 9 species were less attacked than Lactuca sativa, which was readily taken. Plants containing quinolizidine alkaloids were studied in detail. Those species with the α-pyridone alkaloids cytisine and N-methylcytisine were avoided to a higher extent than plants with lupanine as the major alkaloid. Since the repellency observed could be due to other natural products present in the plants besides the alkaloids, the feeding response of Helix pomatia was tested on artificial diets containing quinolizidine alkaloids in various concentrations as the only variable. If the snails had the choice they clearly preferred alkaloid-free food or a diet with only low alkaloid concen­trations. Half-maximal repellency of cytisine is less than 2 mᴍ, of sparteine 1-5 mᴍ, and of lupanine 1-8mᴍ. Since the in vivo concentrations of sparteine, cytisine, and lupanine are equal to or higher than the inhibitory concentrations required it is concluded that quinolizidine alkaloids constitute a potential antimolluscan principle of legumes.


Zootaxa ◽  
2019 ◽  
Vol 4623 (2) ◽  
pp. 364-380
Author(s):  
MARIA EUGENIA GONZALEZ-CANALES ◽  
JOSE A. CUESTA ◽  
JUAN IGNACIO GONZÁLEZ-GORDILLO

The complete larval development of Petrolisthes tuberculatus (including two zoeal stages and the megalopa) is described and illustrated in detail for the first time, based on laboratory-reared material. In order to allow the differentiation of specimens from plankton samples, the larval stages of P. tuberculatus are compared with those known for other porcellanid crabs from Chilean waters (Allopetrolisthes angulosus, Petrolisthes granulosus, P. laevigatus and P. violaceus). As expected, this comparison lead to the inclusion of P. tuberculatus within the “sección Porcellanina” together with the other Chilean species of porcellanids. 


1983 ◽  
Vol 115 (9) ◽  
pp. 1109-1117 ◽  
Author(s):  
G. T. Harvey

AbstractLaboratory studies of the mean weights of initial eggs (Ei) of the spruce budworm, Choristoneura fumiferana (Clem.), show that this value is determined by the genetic constitution of the female moth and is relatively independent of environmental control. Dietary differences experienced by the female during larval development, and originating from different hosts or from reduced nutrient levels in artificial diets, did not affect Ei values; however, depletion of nutrients sufficient to reduce fertility greatly did reduce Ei. Temperature conditions during the ultimate larval and pupal stages influence Ei values which vary inversely. Mean egg weights are strongly heritable and are readily selected for, thereby demonstrating the presence of strong genetic control.


2020 ◽  
Vol 8 (3) ◽  
pp. 213 ◽  
Author(s):  
Il-Kweun Oh ◽  
Seung-Woo Lee

Deiratonotus japonicus (D. japonicus) inhabits isolated locations and upstream brackish waters from Kanagawa Prefecture to Okinawa Prefecture in Japan. This species faces the threat of extinction because of changing habitat conditions. Our previous studies have shown that its complete larval development from hatching to metamorphosis consists of five zoeal stages and one megalopal stage. In this study, the effect of temperature on the survival and growth of larval development in D. japonicus under controlled laboratory conditions of 13, 18, 23, 24, 25, and 26 °C was investigated by rearing larvae (30 PSU; 12:12 h light/dark cycle; fed a diet of Brachionus plicatilis rotundiformis and Artemia sp. nauplii). The survival rates and developmental periods were measured for each larval stage. The highest survival rates were obtained at 18–24 °C. Metamorphosis to megalopa occurred at 23–25 °C. There were rapid and synchronous developments at 25–26 °C but delayed and extended developments at 13 °C. The molting period decreased with increasing temperature. With decreasing temperature, the beginning of the development and duration of molting was prolonged. In addition, there were very low survival rates at 13 °C and 26 °C in all zoeal stages. Our results indicate that the early larval stages of D. japonicus are well adapted to 18–24 °C, the range observed in the estuarine marine environment of the Kita River during the breeding season. Optimum larval survival and growth were obtained at 23 °C. Temperature significantly affected the survival rate, developmental period, and molting of the larvae. The relationship between the cumulative periods of development from hatching through individual larval stages (y) and temperatures (T) was described as a power function (y = a × Tb).


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