Population and Mortality Assessment During the Egg and Larval Stages of the Larch Sawfly, Pristiphora erichsonii (Htg.)

1962 ◽  
Vol 94 (3) ◽  
pp. 256-268 ◽  
Author(s):  
W. G. H. Ives

This contribution is the eighth in a series of papers on sampling techniques used in population studies of the larch sawfly (Ives, 1955; Ives and Prentice, 1958; Buckner, 1959; Ives, 1959; Ives and Prentice, 1959; Ives and Turnock, 1959; and Turnock, 1960). Although the greatest proportionate mortality usually occurs in the cocoon stage of this insect, the largest amount of mortality in terms of absolute numbers occurs between oviposition and the completion of larval feeding. This paper presents a method for estimating seasonal increments to the egg and larval populations and alternative methods for estimating mortality during these stages. Examples are also provided of the integration of these methods with previously developed techniques for estimating egg populations and foliage weight.

1959 ◽  
Vol 91 (8) ◽  
pp. 513-519 ◽  
Author(s):  
W. G. H. Ives

This paper is one in a series on sampling techniques used in population studies of the larch sawfly (Ives, 1955; Ives and Prentice, 1958). The technique has been developed to provide bases for comparing the intensity of sawfly infestations in stands of different compositions, and for studying the effect of the insect upon its host. A preliminary study demonstrated the feasibility of developing a sampling method for estimating foliage weight, but also indicated that the foliage weight increased as the season progressed (Ives, 1958). Foliage sampling in stands infested by the larch sawfly must be completed before defoliation becomes prevalent, and the foliage weight may increase considerably after sampling. In 1956 an intensive sampling program was carried out on tamarack in the Whiteshell Forest Reserve, Manitoba, to determine the sample size needed to obtain statistically acceptable estimates of foliage production and to study the nature of changes in foliage weight during the season.


1968 ◽  
Vol 100 (5) ◽  
pp. 470-475 ◽  
Author(s):  
R. J. Heron

AbstractLarvae of the larch sawfly, Pristiphora erichsonii (Htg.), were fed foliage of tamarack, Larix laricina (Du Roi) K. Koch, treated with solutions of the vital dyes, Nile blue sulphate, rhodamine B, and coriphosphine O, to determine their suitability as markers. Coriphosphine O was highly toxic at the concentrations administered but successful tagging was obtained with the other two dyes. Optimal dye retention and survival were obtained when larvae were fed for 3 days early in the last stadium using Nile blue sulphate and throughout the last stadium using rhodamine B.Both dyes persisted throughout development and were incorporated in the cocoons and the oviposited eggs. They could be readily seen in all stages except for the cocoons and for eggs that contained rhodamine B. The dyes could be detected in cocoons by treating them with cold KOH followed by ethanol. The presence of rhodamine B in the eggs could be ascertained by its yellow fluorescence in ultraviolet.The dyes incorporated in the cocoons are relatively stable and laboratory tests indicate they probably can withstand weathering under normal field conditions over a 1-year period.The use of these dyes for internal marking should prove useful in studying adult dispersal and flight range and as a technique for use in population studies of the larch sawfly.


1955 ◽  
Vol 87 (10) ◽  
pp. 417-427 ◽  
Author(s):  
R. J. Heron

Larvae of the larch sawfly, Pristiphora erichsonii (Htg.), feed on the foliage of conifers of the genus Larix. In Manitoba and Saskatchewan, where the studies described here were conducted, the native host is tamarack, L. laricina (Du Roi) K. Koch. At outbreak population levels larval feeding commonly causes complete defoliation. Trees show a marked reduction in foliage production after three or four successire vears af severe defoliation (6). As a consequence, larval starvation is commonly associated with declining host vigour. Starvation reduces the population size directly by causing larval mortality and indirectly by reducing the reproductive capacity of the partially starved survivors. This paper deals primarily with the measurement of the sub-lethal effects of starvation during the last larval stadium as studied in laboratory-reared and field-collected insects.


1958 ◽  
Vol 90 (6) ◽  
pp. 331-338 ◽  
Author(s):  
W. G. H. Ives ◽  
R. M. Prentice

Sequential sampling methods have been developed for population surveys of a number of forest insects (4, 6, 7, 9). These methods permit rapid classification of populations into broad infestation classes with predetermined accuracy and a minimum of sampling, and are useful for mapping and recording widespread infestations.The method of assessing egg populations of the larch sawfly, Pristiphora erichsonii (Htg.), developed by Ives (3) for intensive population studies, was not suitable for surveys because of the large sample size required. A sequential plan for the larch sawfly using hypothetical infestation classes was briefly reviewed by Ives (2). This plan is modified in the present paper in accordance with new data that have accumulated from observations on plots in the Whiteshell Forest Reserve and other stands in Manitoba and Saskatchewan.


1997 ◽  
Vol 48 (5) ◽  
pp. 401 ◽  
Author(s):  
Jesse D. Ronquillo ◽  
Toshio Saisho

Gravid females of Metapenaeopsis barbata spawned in the laboratory by natural means and the larvae were reared from hatching to postlarval stage at 27·0–29·8˚C and 33·5–34·5 g kg -1 salinity. The larvae metamorphosed into first postlarvae, with a survival rate of up to 98·4%, after about 10 days following hatching and subsistence on only an algal diet of Tetraselmis tetrathele and Chaetoceros gracilis. Six naupliar stages, three protozoeal stages, three mysis stages and the first postlarval stage are described and illustrated. On the basis of morphological characteristics, larval stages of M. barbata can be distinguished from similar stages of closely related species in the family Penaeidae. As inferred from the morphology of the larval feeding apparatus, M. barbata is still a filter-feeder even at the first postlarval stage.


Author(s):  

Abstract A new distribution map is provided for Pristiphora erichsonii (Htg.) (Hymenopt., Tenthredinoidea) (Larch Sawfly). Hosts: Larix spp. Information is given on the geographical distribution in EUROPE (excl. USSR), Austria, Britain, Czechoslovakia, Denmark, Finland, France, Germany, Ireland, Netherlands, Norway, Poland, Rumania, Sweden, ASIA (excl. USSR), Japan, USSR, NORTH AMERICA, Canada, U.S.A.


2011 ◽  
Vol 83 (4) ◽  
pp. 1269-1278 ◽  
Author(s):  
Fernando A. Abrunhosa ◽  
Darlan J.B. Simith ◽  
Joely R.C. Monteiro ◽  
Antonio N. de Souza Junior ◽  
Pedro A.C. Oliva

Feeding is an important factor for the successful rearing of larvae of the crab species. Further information on the morphological features of the foregut may to reveal larval feeding behaviour and or/whether there is a lecithotrophy in some or even in all stages of the larval cycle. In the present study, the structural development of the foregut and their digestive functions were examined in larvae of two brachyurans, Uca vocator and Panopeus occidentalis, reared in the laboratory. During larval development, the foreguts of the larvae in the first and last zoeal stages and in the megalopa stage were microscopically examined, described and illustrated. The zoeal foreguts of both species were well developed, showing specialization with a functional cardiopyloric valve and a filter press. The megalopa stage had a complex and specialized gastric mill similar to that found in adult crabs with the appearance of rigidly calcified structures. These results support the hypothesis that the feeding behaviour of each larval stage is directly related to the morphological structure of the foregut. Such facts strongly indicate that all larval stages of both . vocator and P occidentalis need an external food source before completing the larval development in a planktonic environment.


1959 ◽  
Vol 91 (8) ◽  
pp. 496-500 ◽  
Author(s):  
W. G. H. Ives ◽  
R. M. Prentice

The Forest Insect Survey at the Forest Biology Laboratory, Winnipeg, has been compiling records for a number of years on the percentage of cocoons of the larch sawfly, Pristiphora erichsonii (Htg.), parasitized by the tachinid Bessa harveyi Tnsd. Sawfly cocoons were collected each fall from the soil in infested stands, and those containing living larvae were dissected to determine the percentage of parasitism by B. harveyi. These estimates have been used to provide an index of parasitism (Lejeune and Hildahl, 1954), but are of limited value for a number of reasons: (1) estimates can be expressed only as percentage of sound cocoons parasitized; (2) total parasitism cannot be estimated because a portion of the parasites emerge from the cocoons before collection; and (3) estimates of parasitism may not be representative of the stand because there is a tendency to collect cocoons where they are easiest to find; hence all the cocoons in a collection may be from one or two small areas. If the proportion of cocoons containing B. harveyi varies within a stand such collections may give unreliable estimates of parasitism.


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