DIAPAUSE INDUCTION AND OVERWINTERING STAGE IN THE FIR CONEWORM (LEPIDOPTERA: PYRALIDAE)

1999 ◽  
Vol 131 (6) ◽  
pp. 779-786 ◽  
Author(s):  
Richard Trudel ◽  
Éric Bauce ◽  
Claude Guertin ◽  
Jean Cabana

AbstractA laboratory experiment was conducted to identify the overwintering stage of the fir coneworm, Dioryctria abietivorella (Grote), in eastern Canada and determine the influence of photoperiod on diapause induction. In another experiment, different developmental stages were exposed to field conditions to evaluate their capacity to survive the overwintering period. Insects were either placed in the duff or exposed to ambient (above ground) conditions to assess the importance of overwintering site on winter survival. Exposure of the fir coneworm to constant short-days or a daily decreasing photoperiod during larval development induced almost all insects to initiate diapause at the fifth instar. Third-, fourth-, and fifth-instar larvae survived the overwintering period when placed in the duff. Because the fir coneworm must leave its host tree and drop to the ground to avoid rigorous winter conditions, we concluded that only fifth-instar larvae could resume development in spring using such a strategy.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fang Li ◽  
Zaichao Zheng ◽  
Hongyu Li ◽  
Rongrong Fu ◽  
Limei Xu ◽  
...  

AbstractDespite the central role of hemocytes in crustacean immunity, the process of hemocyte differentiation and maturation remains unclear. In some decapods, it has been proposed that the two main types of hemocytes, granular cells (GCs) and semigranular cells (SGCs), differentiate along separate lineages. However, our current findings challenge this model. By tracking newly produced hemocytes and transplanted cells, we demonstrate that almost all the circulating hemocytes of crayfish belong to the GC lineage. SGCs and GCs may represent hemocytes of different developmental stages rather than two types of fully differentiated cells. Hemocyte precursors produced by progenitor cells differentiate in the hematopoietic tissue (HPT) for 3 ~ 4 days. Immature hemocytes are released from HPT in the form of SGCs and take 1 ~ 3 months to mature in the circulation. GCs represent the terminal stage of development. They can survive for as long as 2 months. The changes in the expression pattern of marker genes during GC differentiation support our conclusions. Further analysis of hemocyte phagocytosis indicates the existence of functionally different subpopulations. These findings may reshape our understanding of crustacean hematopoiesis and may lead to reconsideration of the roles and relationship of circulating hemocytes.


1997 ◽  
Vol 129 (1) ◽  
pp. 197-198 ◽  
Author(s):  
Richard Trudel ◽  
Éric Bauce ◽  
Jean Cabana ◽  
Claude Guertin

The fir coneworm, Dioryctria abietivorella (Grote), is a major insect pest in seed orchards across Canada and the adjoining eastern and western United States. Larvae feed principally on cones, but they can also feed on needles and occasionally on the bark of young tree trunks (Hedlin et al. 1980; Ruth 1980; Martineau 1985). The potential for a population of D. abietivorella to build up in seed orchards may be greater than in natural stands (Hedlin et al. 1980; Ruth et al. 1982). The use of entomopathogen in the management of fir coneworm could be an adequate measure to reduce the impact of this insect. Moreover, Bacillus thuringiensis ssp. kurstaki has a specific effect on Lepidoptera (Aronson et al. 1986; Gill et al. 1992). The purpose of our study was to determine the activity of the HD-1 strain of B. thuringiensis ssp. kurstaki (serotype H-3a:3b) to larvae D. abietivorella. Bioassays were conducted with first-, third-, and fifth-instar larvae of fir coneworm to determine whether or not the insect's vulnerability to B. thuringiensis varies with larval age.


2020 ◽  
Vol 21 (4) ◽  
pp. 1230
Author(s):  
Gangqiao Kuang ◽  
Wenjing Tao ◽  
Shuqing Zheng ◽  
Xiaoshuang Wang ◽  
Deshou Wang

Ribosomal proteins (RPs) are indispensable in ribosome biogenesis and protein synthesis, and play a crucial role in diverse developmental processes. In the present study, we carried out a comprehensive analysis of RPs in chordates and examined the expression profiles of the complete set of 92 cytoplasmic RP genes in Nile tilapia. The RP genes were randomly distributed throughout the tilapia genome. Phylogenetic and syntenic analyses revealed the existence of duplicated RP genes from 2R (RPL3, RPL7, RPL22 and RPS27) and 3R (RPL5, RPL19, RPL22, RPL41, RPLP2, RPS17, RPS19 and RPS27) in tilapia and even more from 4R in common carp and Atlantic salmon. The RP genes were found to be expressed in all tissues examined, but their expression levels differed among different tissues. Gonadal transcriptome analysis revealed that almost all RP genes were highly expressed, and their expression levels were highly variable between ovaries and testes at different developmental stages in tilapia. No sex- and stage-specific RP genes were found. Eleven RP genes displayed sexually dimorphic expression with nine higher in XY gonad and two higher in XX gonad at all stages examined, which were proved to be phenotypic sex dependent. Quantitative real-time PCR and immunohistochemistry ofRPL5b and RPL24 were performed to validate the transcriptome data. The genomic resources and expression data obtained in this study will contribute to a better understanding of RPs evolution and functions in chordates.


1978 ◽  
Vol 110 (12) ◽  
pp. 1351-1353 ◽  
Author(s):  
D. G. R. McLeod

AbstractGrowth rate, diapause incidence, and diapause intensity were different in two strains of corn borers found in southwestern Ontario. Crosses between these two strains demonstrated that growth rate was female sex linked while diapause incidence was male sex linked. The effect of these two characteristics on hybridization is discussed.


2001 ◽  
Vol 11 (03n04) ◽  
pp. 125-131 ◽  
Author(s):  
Y. WATANABE ◽  
S. HOMMA-TAKEDA ◽  
M. YUKAWA ◽  
Y. NISHIMURA ◽  
H. IMASEKI

Micro-PIXE and inductively coupled plasma mass spectrometry (ICP-MS) were applied to elemental distribution analyses in plant root apex which is composed of various types of tissues and cells in different developmental stages. ICP-MS was so sensitive that a large number of elements including Na, Mg, P, S, K, Ca, Mn, Fe, Cu, Zn, Se, Rb, Sr and Cs could be determined quantitatively. These fourteen elements included almost all the essential elements for plant growth. Only a rough estimation, however, could be obtained by ICP-MS for the elemental distribution at the tissue level, by analyzing sections from the root apex. On the other hand, micro-PIXE was effective for detailed mappings of elemental distributions. The images of elemental distributions were obtained for Na, Mg, P, S, K, Ca, Mn, Fe and Zn, corresponding to the microscopic images of the root structures. The localizations of P, K and Zn in some tissues were observed by the mappings. These results indicated that micro-PIXE and ICP-MS have different, but complementary abilities for the investigation of elemental distributions in plant tissues.


1959 ◽  
Vol 91 (9) ◽  
pp. 596-599 ◽  
Author(s):  
N. R. Brown ◽  
R. C. Clark

Aphidecta obliterata (L.) is a common predator on conifer-infesting adelgids and aphids in Western Europe, including Scandinavia and the British Isles (Wylie, 1958b). The life cycle in Europe and descriptions of the various stages have been published (Weise, 1892; Portevin, 1931; Van Emden, 1949; Van Dinther, 1951; Wylie, 1958a). Beginning in 1941 several attempts have been made to introduce this species into Eastern Canada against the balsam woolly aphid, Adelges piceae (Ratz.). The initial liberations from England and Germany were apparently unsuccessful due to the inability of the insect to survive the Canadian winter conditions. Later collections were made in Sweden, Czechoslovakia, and Switzerland (Table I) from areas where the winter conditions more closely resemble those in Canada. These liberations also proved unsuccessful. The present paper brings together all available information on the liberations and related experiments olbtained during the liberation years.


1974 ◽  
Vol 106 (9) ◽  
pp. 969-978 ◽  
Author(s):  
Maurice J. Tauber ◽  
Catherine A. Tauber

AbstractThe adults of Chrysopa harrisii Fitch, which are not predaceous, overwinter in a state of reproductive diapause. During both the dormant and the reproductive periods they remain dark green, a colour apparently adapted to the species’ occurrence on conifers. Two to three generations per season are possible in the Ithaca, N.Y., area.At 75°F, which is the optimum constant temperature for development and survival, the time from oviposition to adult eclosion is 29 days. Theoretical thresholds for development of all stages are relatively high, between 50° and 57°F, and development from egg to adult requires 566 heat degree days.In the laboratory, the critical photoperiod for diapause induction is between LD 13:11 and LD 14:10; short days maintain diapause for approximately 45 days (at 75°F); long days terminate diapause. Both newly-emerged and reproductively-active adults are extremely sensitive to diapause-inducing photoperiods. In the field, all adults emerging on 5 September or later enter diapause and it appears that diapause induction in the Ithaca population begins in the latter part of August. Short days maintain diapause until the end of December, and neither long days, increasing day lengths, nor low temperatures play a role in hastening diapause termination in nature.In timing its vernal reproduction, C. harrisii has evolved a strategy that combines an early-ending diapause with an apparently relatively high temperature threshold for post-diapause development. Therefore, although diapause ends around the winter solstice, heat accumulation is prevented until much later, when temperatures are relatively high.


2021 ◽  
Vol 6 (4) ◽  
pp. 459-468
Author(s):  
Suleyman CAGIR ◽  
Yakup Onur KOCA

Due to the different agricultural practices such as second cropping or more for the increase product obtained from the areas of suitable climate, some differences in harvesting stages of plants have been occurred. The study was carried out in the Menemem location of Izmir in the coastal Aegean region of Turkey under Mediterranean climate in 2018 and 2019 to determine the performance of corn cultivars in different maturity stages. Seven varieties of corn (Everest, Aga, Kilowatt, Burak, Samada-07, P30B74 and P31Y43) were harvested at 3 different growth stages (silking, end of milk and dough stages) to determine the changes in some parameters of growing, forage quantity and quality. The highest average of dry forage yield (24159 kg ha-1 average of years) was determined at the third harvest date. The maximum cob rate was also measured at the third harvest date, but the maximum leaf and stalk rates were measured at the first harvest date. The average protein rate decreased throughout the growing period while ADF and NDF increased. Almost all of the varieties were found to have large leaf areas. The Burak variety came to the fore due to its long length and relatively thick stalk features and high green and dry yields. Moreover, P31Y43 was determined to have a high quality in addition to high green and dry grass yields. Therefore, the Burak and P31Y43 can be suggested in terms of high parameters both quantity and quality under different crop conditions for increase production.


2017 ◽  
Vol 40 (2) ◽  
pp. 151-154
Author(s):  
N. Roychoudhury ◽  
◽  
P.B. Meshram ◽  
Ashish Pandey ◽  
Neha Prajapati ◽  
...  

The present paper reports the occurrence of leaf roller, Sylepta derogata Fabricius (Lepidoptera : Pyralidae) on back mangrove, Hibiscus tiliaceus Linn. (family Malvaceae), exists in Bhitarkanika National Park, Rajnagar (Mangrove) Forest Division, Kendrapara, Odisha. Some biological observations and morphometric data on developmental stages of leaf roller has been studied and reported.


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