Head Capsule Width of Larval Populations of the Gypsy Moth (Lepidoptera: Lymantriidae) in Quebec, with Reference to Dyar's Hypothesis

Jobin, Luc; Hébert, Christian; Bourassa, J.-P.

doi:10.1093/ee/21.1.89

Cited by 17 publications

(10 citation statements)

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“…Also, the successive larval instars of a given species show more or less regular geometrical progres sion in the growth of head capsule. However, Dyar's hypothesis applies in some cases (Fox et al 1972), but not in others (Jobin et al 1992). Dyar's hypothesis that proposes a con stant growth ratio throughout larval development in Lepidop tera disagrees with our results for last instar both for those completed 5 or 6 instars.…”

Section: Resultsmentioning

confidence: 99%

Determination of Helicoverpa armigera (Lepidoptera: Noctuidae) larval instars and age based on head capsule width and larval weight

Stavridis

Katarachias

et al. 2017

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Larνae of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) were reared in laboratory conditions (26°C, 16:8 L:D) and measurements of larval head capsule width, and body weight, were used in order to determine the boundaries of larval instars. Larvae of Η. armigera completed development in 5 to 7 instars. Head capsule width could predict the larval instar only for Ll. The upper boundary of head width for L1 was 0.4mm. Body weight could predict both L1 and L2 larval instars. Boundaries between L1-L2 instars were found to be 1 mg and for L2-L3 5,5 mg. Correlation and regression analysis suggest that a combination of head capsule width and body weight can predict both larval instars and chronological age under constant conditions in the laboratory.

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Section: Resultsmentioning

confidence: 99%

Determination of Helicoverpa armigera (Lepidoptera: Noctuidae) larval instars and age based on head capsule width and larval weight

Stavridis

Katarachias

et al. 2017

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“…Such prolonged larval development has been reported earlier by Ishikubo (1967) when reared with fresh inner bark in test tubes. For many insect species, variation in the number of instars occurs frequently due to shortage of food quality (Jobin et al 1992, Esperk et al 2007, Calvo and Molina 2008). Calvo and Molina (2008) have reported that the number of instars of moth Streblote panda Hubner (Lepidoptera: Lasiocampidae) varies from 5 to 8 depending on host plants.…”

Section: Discussionmentioning

confidence: 99%

The Developmental Characteristics for the Head Capsule Width ofMonochamus alternatus(Coleoptera: Cerambycidae) Larvae and Determination of the Number of Instars

Kwon

Kim

et al. 2019

Journal of Insect Science

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The objective of this study was to determine the number of instars of Monochamus alternatus Hope (Coleoptera: Cerambycidae) larvae by comparing their head capsule widths (HCW) published in previous studies, as well as additional laboratory experiments. Larvae of M. alternatus showed repeated molting in the laboratory. Most larvae ceased their development at the 10th instar stage. Frequency distributions of HCW for the first, second, and third instar larvae were clearly separated while those of the fourth through 11th instar larvae largely overlapped between successive instars in our results. The HCW values for the first, second, and third instar larvae directly measured for each instar in our study indicated that they were more precise than those of previous reports based on field-collected HCW which might have missed HCW of the first instar larvae or wrongly determined HCW for some instars. Unlike the reports of four instars of previous studies, M. alternatus larvae passed five instars in the field, which was confirmed by the discovery of five pairs of mandibles in the feeding gallery and pupal chamber. Also, the comparative study for the frequency distributions of HCW revealed that most M. alternatus larvae passed five instars. Consequently, the average sizes of HCW for their first, second, and third instar larvae are newly suggested to be 0.896 ± 0.069, 1.291 ± 0.131, and 1.707 ± 0.165 mm (mean ± SD) .

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“…The so called Dyar's rule has been confirmed for a lot of arthropods (Taylor, 1931;Elliott, 2009) and it has occasionally been used to determine the number of instars of some species (Gaines and Campbell, 1935). Several authors, however, have reported deviations from Dyar's rule ( Drooz, 1965;Hoxie and Wellso, 1974;Jobin et al, 1992;Andersson, 1976Andersson, , 1978bAndersson, , 1980Albert, 1982, Cole, 1980. Dyar (1890) also found that the factor by which caterpillars grow in successive moult is the same for all species, about 1.26 when body length (BL) and about 2 when weight is considered.…”

Section: Introductionmentioning

confidence: 97%

Deviation of Dyar’s rule in the post-embryonic development in millipedes – a comprehensive analysis

Bhakat¹

2020

Preprint

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Dyar’s value on the basis of length and width of nine polydesmid and 15 non-polydesmid millipede species were calculated. The value of polydesmid millipede ranged from 1.50 to 1.78 and that of non-polydesmid millipede ranged from 1.08 to 1.45. Weight progression factor was determined for nine species of millipede (two polydesmid and seven non-polydesmids). The result showed that the mean weight progression factor in polydesmid is 2.54 while that of non-polydesmid is 1.95. Both the results showed that Dyar’s value in polydesmida is significantly higher compared to that of non-polydesmida. In polydesmida, the number of stadium is only eight with higher Dyar’s value (mean 1.61) while in non-polydesmida, where number of stadium is more than eight have lower Dyar’s value (mean 1.23). As in other arthropods, Dyar’s value is inversely proportional to the number of stadium in millipede.The present study also affirmed Enders’ hypothesis in favour of adaptive importance of Dyar’s rule. Deviations from Dyar’s constant in these two group also support Crossby’s growth rule. The variation of Dyar’s value in these two groups of millipede is related to the development time and habitat utilization. The variation of weight progression factor in these two groups is also linked to the development time as observed in other arthropods.

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Head Capsule Width of Larval Populations of the Gypsy Moth (Lepidoptera: Lymantriidae) in Quebec, with Reference to Dyar's Hypothesis

Cited by 17 publications

References 0 publications

Determination of Helicoverpa armigera (Lepidoptera: Noctuidae) larval instars and age based on head capsule width and larval weight

Determination of Helicoverpa armigera (Lepidoptera: Noctuidae) larval instars and age based on head capsule width and larval weight

The Developmental Characteristics for the Head Capsule Width ofMonochamus alternatus(Coleoptera: Cerambycidae) Larvae and Determination of the Number of Instars

Deviation of Dyar’s rule in the post-embryonic development in millipedes – a comprehensive analysis

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